TY - JOUR A1 - Kirchler, Matthias A1 - Konigorski, Stefan A1 - Norden, Matthias A1 - Meltendorf, Christian A1 - Kloft, Marius A1 - Schurmann, Claudia A1 - Lippert, Christoph T1 - transferGWAS BT - GWAS of images using deep transfer learning JF - Bioinformatics N2 - Motivation: Medical images can provide rich information about diseases and their biology. However, investigating their association with genetic variation requires non-standard methods. We propose transferGWAS, a novel approach to perform genome-wide association studies directly on full medical images. First, we learn semantically meaningful representations of the images based on a transfer learning task, during which a deep neural network is trained on independent but similar data. Then, we perform genetic association tests with these representations. Results: We validate the type I error rates and power of transferGWAS in simulation studies of synthetic images. Then we apply transferGWAS in a genome-wide association study of retinal fundus images from the UK Biobank. This first-of-a-kind GWAS of full imaging data yielded 60 genomic regions associated with retinal fundus images, of which 7 are novel candidate loci for eye-related traits and diseases. Y1 - 2022 U6 - https://doi.org/10.1093/bioinformatics/btac369 SN - 1367-4803 SN - 1460-2059 VL - 38 IS - 14 SP - 3621 EP - 3628 PB - Oxford Univ. Press CY - Oxford ER - TY - THES A1 - Lorson, Annalena T1 - Understanding early stage evolution of digital innovation units in manufacturing companies T1 - Verständnis der frühphasigen Entwicklung digitaler Innovationseinheiten in Fertigungsunternehmen N2 - The dynamic landscape of digital transformation entails an impact on industrial-age manufacturing companies that goes beyond product offerings, changing operational paradigms, and requiring an organization-wide metamorphosis. An initiative to address the given challenges is the creation of Digital Innovation Units (DIUs) – departments or distinct legal entities that use new structures and practices to develop digital products, services, and business models and support or drive incumbents’ digital transformation. With more than 300 units in German-speaking countries alone and an increasing number of scientific publications, DIUs have become a widespread phenomenon in both research and practice. This dissertation examines the evolution process of DIUs in the manufacturing industry during their first three years of operation, through an extensive longitudinal single-case study and several cross-case syntheses of seven DIUs. Building on the lenses of organizational change and development, time, and socio-technical systems, this research provides insights into the fundamentals, temporal dynamics, socio-technical interactions, and relational dynamics of a DIU’s evolution process. Thus, the dissertation promotes a dynamic understanding of DIUs and adds a two-dimensional perspective to the often one-dimensional view of these units and their interactions with the main organization throughout the startup and growth phases of a DIU. Furthermore, the dissertation constructs a phase model that depicts the early stages of DIU evolution based on these findings and by incorporating literature from information systems research. As a result, it illustrates the progressive intensification of collaboration between the DIU and the main organization. After being implemented, the DIU sparks initial collaboration and instigates change within (parts of) the main organization. Over time, it adapts to the corporate environment to some extent, responding to changing circumstances in order to contribute to long-term transformation. Temporally, the DIU drives the early phases of cooperation and adaptation in particular, while the main organization triggers the first major evolutionary step and realignment of the DIU. Overall, the thesis identifies DIUs as malleable organizational structures that are crucial for digital transformation. Moreover, it provides guidance for practitioners on the process of building a new DIU from scratch or optimizing an existing one. N2 - Die digitale Transformation produzierender Unternehmen geht über die bloße Veränderung des Produktangebots hinaus; sie durchdringt operative Paradigmen und erfordert eine umfassende, unternehmensweite Metamorphose. Eine Initiative, den damit verbundenen Herausforderungen zu begegnen, ist der Aufbau einer Digital Innovation Unit (DIU) (zu deutsch: digitale Innovationseinheit) – eine Abteilung oder separate rechtliche Einheit, die neue organisationale Strukturen und Arbeitspraktiken nutzt, um digitale Produkte, Dienstleistungen und Geschäftsmodelle zu entwickeln und die digitale Transformation von etabliertenUnternehmen zu unterstützen oder voranzutreiben. Mit mehr als 300 Einheitenallein im deutschsprachigen Raum und einer wachsenden Zahl wissenschaftlicher Publikationen sind DIUs sowohl in der Forschung als auch in der Praxis ein weit verbreitetes Phänomen. Auf Basis einer umfassenden Längsschnittstudie und mehrerer Querschnittsanalysen von sieben Fertigungsunternehmen und ihren DIUs untersucht diese Dissertation den Entwicklungsprozess von DIUs in den ersten drei Betriebsjahren. Gestützt auf theoretische Perspektiven zu organisatorischem Wandel, Zeit und sozio-technischen Systemen bietet sie Einblicke in die Grundlagen, die zeitlichen Dynamiken, die sozio-technischen Interaktionen und die Beziehungsdynamiken des Entwicklungsprozesses von DIUs. Die Dissertation erweitert somit das dynamische Verständnis von DIUs und fügt der oft eindimensionalen Sichtweise auf diese Einheiten und ihre Interaktionen mit der Hauptorganisation eine zweidimensionale Perspektive entlang der Gründungs- und Wachstumsphasen einer DIU hinzu. Darüber hinaus konstruiert die Dissertation ein Phasenmodell, das die frühen Phasen der DIU-Entwicklung auf der Grundlage dieser Erkenntnisse und unter Einbeziehung von Literatur aus der Wirtschaftsinformatikforschung abbildet. Es veranschaulicht die schrittweise Intensivierung der Zusammenarbeit zwischen der DIU und der Hauptorganisation. Nach ihrer Implementierung initiiert die DIU die anfängliche Zusammenarbeit und stößt Veränderungen innerhalb (von Teilen) der Hauptorganisation an. Im Laufe der Zeit passt sich die DIU bis zu einem gewissen Grad dem Unternehmensumfeld an und reagiert auf sich verändernde Umstände, um zu einer langfristigen Veränderung beizutragen. Zeitlich gesehen treibt die DIU vor allem die frühen Phasen der Zusammenarbeit und Anpassung voran, während die Hauptorganisation den ersten großen Entwicklungsschritt und die Neuausrichtung der DIU auslöst. Insgesamt identifiziert die Dissertation DIUs als anpassungsfähige Organisationsstrukturen, die für die digitale Transformation entscheidend sind. Darüber hinaus bietet sie Praktikern einen Leitfaden für den Aufbau einer neuen oder die Optimierung einer bestehenden DIU. KW - digital transformation KW - digital innovation units KW - evolution of digital innovation units KW - manufacturing companies KW - digitale Transformation KW - digitale Innovationseinheit KW - Entwicklung digitaler Innovationseinheiten KW - Fertigungsunternehmen Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-639141 ER - TY - JOUR A1 - Cseh, Agnes A1 - Faenza, Yuri A1 - Kavitha, Telikepalli A1 - Powers, Vladlena T1 - Understanding popular matchings via stable matchings JF - SIAM journal on discrete mathematics N2 - An instance of the marriage problem is given by a graph G = (A boolean OR B, E), together with, for each vertex of G, a strict preference order over its neighbors. A matching M of G is popular in the marriage instance if M does not lose a head-to-head election against any matching where vertices are voters. Every stable matching is a min-size popular matching; another subclass of popular matchings that always exists and can be easily computed is the set of dominant matchings. A popular matching M is dominant if M wins the head-to-head election against any larger matching. Thus, every dominant matching is a max-size popular matching, and it is known that the set of dominant matchings is the linear image of the set of stable matchings in an auxiliary graph. Results from the literature seem to suggest that stable and dominant matchings behave, from a complexity theory point of view, in a very similar manner within the class of popular matchings. The goal of this paper is to show that there are instead differences in the tractability of stable and dominant matchings and to investigate further their importance for popular matchings. First, we show that it is easy to check if all popular matchings are also stable; however, it is co-NP hard to check if all popular matchings are also dominant. Second, we show how some new and recent hardness results on popular matching problems can be deduced from the NP-hardness of certain problems on stable matchings, also studied in this paper, thus showing that stable matchings can be employed to show not only positive results on popular matchings (as is known) but also most negative ones. Problems for which we show new hardness results include finding a min-size (resp., max-size) popular matching that is not stable (resp., dominant). A known result for which we give a new and simple proof is the NP-hardness of finding a popular matching when G is nonbipartite. KW - popular matching KW - stable matching KW - complexity KW - dominant matching Y1 - 2022 U6 - https://doi.org/10.1137/19M124770X SN - 0895-4801 SN - 1095-7146 VL - 36 IS - 1 SP - 188 EP - 213 PB - Society for Industrial and Applied Mathematics CY - Philadelphia ER - TY - THES A1 - Huegle, Johannes T1 - Causal discovery in practice: Non-parametric conditional independence testing and tooling for causal discovery T1 - Kausale Entdeckung in der Praxis: Nichtparametrische bedingte Unabhängigkeitstests und Werkzeuge für die Kausalentdeckung N2 - Knowledge about causal structures is crucial for decision support in various domains. For example, in discrete manufacturing, identifying the root causes of failures and quality deviations that interrupt the highly automated production process requires causal structural knowledge. However, in practice, root cause analysis is usually built upon individual expert knowledge about associative relationships. But, "correlation does not imply causation", and misinterpreting associations often leads to incorrect conclusions. Recent developments in methods for causal discovery from observational data have opened the opportunity for a data-driven examination. Despite its potential for data-driven decision support, omnipresent challenges impede causal discovery in real-world scenarios. In this thesis, we make a threefold contribution to improving causal discovery in practice. (1) The growing interest in causal discovery has led to a broad spectrum of methods with specific assumptions on the data and various implementations. Hence, application in practice requires careful consideration of existing methods, which becomes laborious when dealing with various parameters, assumptions, and implementations in different programming languages. Additionally, evaluation is challenging due to the lack of ground truth in practice and limited benchmark data that reflect real-world data characteristics. To address these issues, we present a platform-independent modular pipeline for causal discovery and a ground truth framework for synthetic data generation that provides comprehensive evaluation opportunities, e.g., to examine the accuracy of causal discovery methods in case of inappropriate assumptions. (2) Applying constraint-based methods for causal discovery requires selecting a conditional independence (CI) test, which is particularly challenging in mixed discrete-continuous data omnipresent in many real-world scenarios. In this context, inappropriate assumptions on the data or the commonly applied discretization of continuous variables reduce the accuracy of CI decisions, leading to incorrect causal structures. Therefore, we contribute a non-parametric CI test leveraging k-nearest neighbors methods and prove its statistical validity and power in mixed discrete-continuous data, as well as the asymptotic consistency when used in constraint-based causal discovery. An extensive evaluation of synthetic and real-world data shows that the proposed CI test outperforms state-of-the-art approaches in the accuracy of CI testing and causal discovery, particularly in settings with low sample sizes. (3) To show the applicability and opportunities of causal discovery in practice, we examine our contributions in real-world discrete manufacturing use cases. For example, we showcase how causal structural knowledge helps to understand unforeseen production downtimes or adds decision support in case of failures and quality deviations in automotive body shop assembly lines. N2 - Kenntnisse über die Strukturen zugrundeliegender kausaler Mechanismen sind eine Voraussetzung für die Entscheidungsunterstützung in verschiedenen Bereichen. In der Fertigungsindustrie beispielsweise erfordert die Fehler-Ursachen-Analyse von Störungen und Qualitätsabweichungen, die den hochautomatisierten Produktionsprozess unterbrechen, kausales Strukturwissen. In Praxis stützt sich die Fehler-Ursachen-Analyse in der Regel jedoch auf individuellem Expertenwissen über assoziative Zusammenhänge. Aber "Korrelation impliziert nicht Kausalität", und die Fehlinterpretation assoziativer Zusammenhänge führt häufig zu falschen Schlussfolgerungen. Neueste Entwicklungen von Methoden des kausalen Strukturlernens haben die Möglichkeit einer datenbasierten Betrachtung eröffnet. Trotz seines Potenzials zur datenbasierten Entscheidungsunterstützung wird das kausale Strukturlernen in der Praxis jedoch durch allgegenwärtige Herausforderungen erschwert. In dieser Dissertation leisten wir einen dreifachen Beitrag zur Verbesserung des kausalen Strukturlernens in der Praxis. (1) Das wachsende Interesse an kausalem Strukturlernen hat zu einer Vielzahl von Methoden mit spezifischen statistischen Annahmen über die Daten und verschiedenen Implementierungen geführt. Daher erfordert die Anwendung in der Praxis eine sorgfältige Prüfung der vorhandenen Methoden, was eine Herausforderung darstellt, wenn verschiedene Parameter, Annahmen und Implementierungen in unterschiedlichen Programmiersprachen betrachtet werden. Hierbei wird die Evaluierung von Methoden des kausalen Strukturlernens zusätzlich durch das Fehlen von "Ground Truth" in der Praxis und begrenzten Benchmark-Daten, welche die Eigenschaften realer Datencharakteristiken widerspiegeln, erschwert. Um diese Probleme zu adressieren, stellen wir eine plattformunabhängige modulare Pipeline für kausales Strukturlernen und ein Tool zur Generierung synthetischer Daten vor, die umfassende Evaluierungsmöglichkeiten bieten, z.B. um Ungenauigkeiten von Methoden des Lernens kausaler Strukturen bei falschen Annahmen an die Daten aufzuzeigen. (2) Die Anwendung von constraint-basierten Methoden des kausalen Strukturlernens erfordert die Wahl eines bedingten Unabhängigkeitstests (CI-Test), was insbesondere bei gemischten diskreten und kontinuierlichen Daten, die in vielen realen Szenarien allgegenwärtig sind, die Anwendung erschwert. Beispielsweise führen falsche Annahmen der CI-Tests oder die Diskretisierung kontinuierlicher Variablen zu einer Verschlechterung der Korrektheit der Testentscheidungen, was in fehlerhaften kausalen Strukturen resultiert. Um diese Probleme zu adressieren, stellen wir einen nicht-parametrischen CI-Test vor, der auf Nächste-Nachbar-Methoden basiert, und beweisen dessen statistische Validität und Trennschärfe bei gemischten diskreten und kontinuierlichen Daten, sowie dessen asymptotische Konsistenz in constraint-basiertem kausalem Strukturlernen. Eine umfangreiche Evaluation auf synthetischen und realen Daten zeigt, dass der vorgeschlagene CI-Test bestehende Verfahren hinsichtlich der Korrektheit der Testentscheidung und gelernter kausaler Strukturen übertrifft, insbesondere bei geringen Stichprobengrößen. (3) Um die Anwendbarkeit und Möglichkeiten kausalen Strukturlernens in der Praxis aufzuzeigen, untersuchen wir unsere Beiträge in realen Anwendungsfällen aus der Fertigungsindustrie. Wir zeigen an mehreren Beispielen aus der automobilen Karosseriefertigungen wie kausales Strukturwissen helfen kann, unvorhergesehene Produktionsausfälle zu verstehen oder eine Entscheidungsunterstützung bei Störungen und Qualitätsabweichungen zu geben. KW - causal discovery KW - causal structure learning KW - causal AI KW - non-parametric conditional independence testing KW - manufacturing KW - causal reasoning KW - mixed data KW - kausale KI KW - kausale Entdeckung KW - kausale Schlussfolgerung KW - kausales Strukturlernen KW - Fertigung KW - gemischte Daten KW - nicht-parametrische bedingte Unabhängigkeitstests Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-635820 ER - TY - JOUR A1 - Casel, Katrin A1 - Fernau, Henning A1 - Ghadikolaei, Mehdi Khosravian A1 - Monnot, Jerome A1 - Sikora, Florian T1 - On the complexity of solution extension of optimization problems JF - Theoretical computer science : the journal of the EATCS N2 - The question if a given partial solution to a problem can be extended reasonably occurs in many algorithmic approaches for optimization problems. For instance, when enumerating minimal vertex covers of a graph G = (V, E), one usually arrives at the problem to decide for a vertex set U subset of V (pre-solution), if there exists a minimal vertex cover S (i.e., a vertex cover S subset of V such that no proper subset of S is a vertex cover) with U subset of S (minimal extension of U). We propose a general, partial-order based formulation of such extension problems which allows to model parameterization and approximation aspects of extension, and also highlights relationships between extension tasks for different specific problems. As examples, we study a number of specific problems which can be expressed and related in this framework. In particular, we discuss extension variants of the problems dominating set and feedback vertex/edge set. All these problems are shown to be NP-complete even when restricted to bipartite graphs of bounded degree, with the exception of our extension version of feedback edge set on undirected graphs which is shown to be solvable in polynomial time. For the extension variants of dominating and feedback vertex set, we also show NP-completeness for the restriction to planar graphs of bounded degree. As non-graph problem, we also study an extension version of the bin packing problem. We further consider the parameterized complexity of all these extension variants, where the parameter is a measure of the pre-solution as defined by our framework. KW - extension problems KW - NP-hardness KW - parameterized complexity Y1 - 2022 U6 - https://doi.org/10.1016/j.tcs.2021.10.017 SN - 0304-3975 SN - 1879-2294 VL - 904 SP - 48 EP - 65 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Coupette, Corinna A1 - Hartung, Dirk A1 - Beckedorf, Janis A1 - Böther, Maximilian A1 - Katz, Daniel Martin T1 - Law smells BT - defining and detecting problematic patterns in legal drafting JF - Artificial intelligence and law N2 - Building on the computer science concept of code smells, we initiate the study of law smells, i.e., patterns in legal texts that pose threats to the comprehensibility and maintainability of the law. With five intuitive law smells as running examples-namely, duplicated phrase, long element, large reference tree, ambiguous syntax, and natural language obsession-, we develop a comprehensive law smell taxonomy. This taxonomy classifies law smells by when they can be detected, which aspects of law they relate to, and how they can be discovered. We introduce text-based and graph-based methods to identify instances of law smells, confirming their utility in practice using the United States Code as a test case. Our work demonstrates how ideas from software engineering can be leveraged to assess and improve the quality of legal code, thus drawing attention to an understudied area in the intersection of law and computer science and highlighting the potential of computational legal drafting. KW - Refactoring KW - Software engineering KW - Law KW - Natural language processing KW - Network analysis Y1 - 2022 U6 - https://doi.org/10.1007/s10506-022-09315-w SN - 0924-8463 SN - 1572-8382 VL - 31 SP - 335 EP - 368 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Tang, Mitchell A1 - Nakamoto, Carter H. A1 - Stern, Ariel Dora A1 - Mehrotra, Ateev T1 - Trends in remote patient monitoring use in traditional Medicare JF - JAMA Internal Medicine N2 - This cross-sectional study uses traditional Medicare claims data to assess trends in general remote patient monitoring from January 2018 through September 2021. Y1 - 2022 U6 - https://doi.org/10.1001/jamainternmed.2022.3043 SN - 2168-6106 SN - 2168-6114 VL - 182 IS - 9 SP - 1005 EP - 1006 PB - American Veterinary Medical Association CY - Chicago ER - TY - JOUR A1 - Cseh, Ágnes A1 - Juhos, Attila T1 - Pairwise preferences in the stable marriage problem JF - ACM Transactions on Economics and Computation / Association for Computing Machinery N2 - We study the classical, two-sided stable marriage problem under pairwise preferences. In the most general setting, agents are allowed to express their preferences as comparisons of any two of their edges, and they also have the right to declare a draw or even withdraw from such a comparison. This freedom is then gradually restricted as we specify six stages of orderedness in the preferences, ending with the classical case of strictly ordered lists. We study all cases occurring when combining the three known notions of stability-weak, strong, and super-stability-under the assumption that each side of the bipartite market obtains one of the six degrees of orderedness. By designing three polynomial algorithms and two NP-completeness proofs, we determine the complexity of all cases not yet known and thus give an exact boundary in terms of preference structure between tractable and intractable cases. KW - Stable marriage KW - intransitivity KW - acyclic preferences KW - poset KW - weakly KW - stable matching KW - strongly stable matching KW - super stable matching Y1 - 2021 U6 - https://doi.org/10.1145/3434427 SN - 2167-8375 SN - 2167-8383 VL - 9 IS - 1 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Cseh, Ágnes A1 - Kavitha, Telikepalli T1 - Popular matchings in complete graphs JF - Algorithmica : an international journal in computer science N2 - Our input is a complete graph G on n vertices where each vertex has a strict ranking of all other vertices in G. The goal is to construct a matching in G that is popular. A matching M is popular if M does not lose a head-to-head election against any matching M ': here each vertex casts a vote for the matching in {M,M '} in which it gets a better assignment. Popular matchings need not exist in the given instance G and the popular matching problem is to decide whether one exists or not. The popular matching problem in G is easy to solve for odd n. Surprisingly, the problem becomes NP-complete for even n, as we show here. This is one of the few graph theoretic problems efficiently solvable when n has one parity and NP-complete when n has the other parity. KW - Popular matching KW - Complexity KW - Stable matching Y1 - 2021 U6 - https://doi.org/10.1007/s00453-020-00791-7 SN - 0178-4617 SN - 1432-0541 VL - 83 IS - 5 SP - 1493 EP - 1523 PB - Springer CY - New York ER - TY - JOUR A1 - Genske, Ulrich A1 - Jahnke, Paul T1 - Human observer net BT - a platform tool for human observer studies of image data JF - Radiology N2 - Background: Current software applications for human observer studies of images lack flexibility in study design, platform independence, multicenter use, and assessment methods and are not open source, limiting accessibility and expandability. Purpose: To develop a user-friendly software platform that enables efficient human observer studies in medical imaging with flexibility of study design. Materials and Methods: Software for human observer imaging studies was designed as an open-source web application to facilitate access, platform-independent usability, and multicenter studies. Different interfaces for study creation, participation, and management of results were implemented. The software was evaluated in human observer experiments between May 2019 and March 2021, in which duration of observer responses was tracked. Fourteen radiologists evaluated and graded software usability using the 100-point system usability scale. The application was tested in Chrome, Firefox, Safari, and Edge browsers. Results: Software function was designed to allow visual grading analysis (VGA), multiple-alternative forced-choice (m-AFC), receiver operating characteristic (ROC), localization ROC, free-response ROC, and customized designs. The mean duration of reader responses per image or per image set was 6.2 seconds 6 4.8 (standard deviation), 5.8 seconds 6 4.7, 8.7 seconds 6 5.7, and 6.0 seconds 6 4.5 in four-AFC with 160 image quartets per reader, four-AFC with 640 image quartets per reader, localization ROC, and experimental studies, respectively. The mean system usability scale score was 83 6 11 (out of 100). The documented code and a demonstration of the application are available online (https://github.com/genskeu/HON, https://hondemo.pythonanywhere.com/). Conclusion: A user-friendly and efficient open-source application was developed for human reader experiments that enables study design versatility, as well as platform-independent and multicenter usability. Y1 - 2022 U6 - https://doi.org/10.1148/radiol.211832 SN - 0033-8419 SN - 1527-1315 VL - 303 IS - 3 SP - 524 EP - 530 PB - Radiological Society of North America CY - Oak Brook, Ill. ER - TY - JOUR A1 - Puri, Manish A1 - Varde, Aparna S. A1 - Melo, Gerard de T1 - Commonsense based text mining on urban policy JF - Language resources and evaluation N2 - Local laws on urban policy, i.e., ordinances directly affect our daily life in various ways (health, business etc.), yet in practice, for many citizens they remain impervious and complex. This article focuses on an approach to make urban policy more accessible and comprehensible to the general public and to government officials, while also addressing pertinent social media postings. Due to the intricacies of the natural language, ranging from complex legalese in ordinances to informal lingo in tweets, it is practical to harness human judgment here. To this end, we mine ordinances and tweets via reasoning based on commonsense knowledge so as to better account for pragmatics and semantics in the text. Ours is pioneering work in ordinance mining, and thus there is no prior labeled training data available for learning. This gap is filled by commonsense knowledge, a prudent choice in situations involving a lack of adequate training data. The ordinance mining can be beneficial to the public in fathoming policies and to officials in assessing policy effectiveness based on public reactions. This work contributes to smart governance, leveraging transparency in governing processes via public involvement. We focus significantly on ordinances contributing to smart cities, hence an important goal is to assess how well an urban region heads towards a smart city as per its policies mapping with smart city characteristics, and the corresponding public satisfaction. KW - Commonsense reasoning KW - Opinion mining KW - Ordinances KW - Smart cities KW - Social KW - media KW - Text mining Y1 - 2022 U6 - https://doi.org/10.1007/s10579-022-09584-6 SN - 1574-020X SN - 1574-0218 VL - 57 SP - 733 EP - 763 PB - Springer CY - Dordrecht [u.a.] ER - TY - JOUR A1 - Bonnet, Philippe A1 - Dong, Xin Luna A1 - Naumann, Felix A1 - Tözün, Pınar T1 - VLDB 2021 BT - Designing a hybrid conference JF - SIGMOD record N2 - The 47th International Conference on Very Large Databases (VLDB'21) was held on August 16-20, 2021 as a hybrid conference. It attracted 180 in-person attendees in Copenhagen and 840 remote attendees. In this paper, we describe our key decisions as general chairs and program committee chairs and share the lessons we learned. Y1 - 2021 SN - 0163-5808 SN - 1943-5835 VL - 50 IS - 4 SP - 50 EP - 53 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Hagedorn, Christiane A1 - Serth, Sebastian A1 - Meinel, Christoph T1 - The mysterious adventures of Detective Duke BT - how storified programming MOOCs support learners in achieving their learning goals JF - Frontiers in education N2 - About 15 years ago, the first Massive Open Online Courses (MOOCs) appeared and revolutionized online education with more interactive and engaging course designs. Yet, keeping learners motivated and ensuring high satisfaction is one of the challenges today's course designers face. Therefore, many MOOC providers employed gamification elements that only boost extrinsic motivation briefly and are limited to platform support. In this article, we introduce and evaluate a gameful learning design we used in several iterations on computer science education courses. For each of the courses on the fundamentals of the Java programming language, we developed a self-contained, continuous story that accompanies learners through their learning journey and helps visualize key concepts. Furthermore, we share our approach to creating the surrounding story in our MOOCs and provide a guideline for educators to develop their own stories. Our data and the long-term evaluation spanning over four Java courses between 2017 and 2021 indicates the openness of learners toward storified programming courses in general and highlights those elements that had the highest impact. While only a few learners did not like the story at all, most learners consumed the additional story elements we provided. However, learners' interest in influencing the story through majority voting was negligible and did not show a considerable positive impact, so we continued with a fixed story instead. We did not find evidence that learners just participated in the narrative because they worked on all materials. Instead, for 10-16% of learners, the story was their main course motivation. We also investigated differences in the presentation format and concluded that several longer audio-book style videos were most preferred by learners in comparison to animated videos or different textual formats. Surprisingly, the availability of a coherent story embedding examples and providing a context for the practical programming exercises also led to a slightly higher ranking in the perceived quality of the learning material (by 4%). With our research in the context of storified MOOCs, we advance gameful learning designs, foster learner engagement and satisfaction in online courses, and help educators ease knowledge transfer for their learners. KW - gameful learning KW - storytelling KW - programming KW - learner engagement KW - course design KW - MOOCs KW - content gamification KW - narrative Y1 - 2023 U6 - https://doi.org/10.3389/feduc.2022.1016401 SN - 2504-284X VL - 7 PB - Frontiers Media CY - Lausanne ER - TY - THES A1 - Halfpap, Stefan T1 - Integer linear programming-based heuristics for partially replicated database clusters and selecting indexes T1 - Auf ganzzahliger linearer Optimierung basierende Heuristiken für partiell-replizierte Datenbankcluster und das Auswählen von Indizes N2 - Column-oriented database systems can efficiently process transactional and analytical queries on a single node. However, increasing or peak analytical loads can quickly saturate single-node database systems. Then, a common scale-out option is using a database cluster with a single primary node for transaction processing and read-only replicas. Using (the naive) full replication, queries are distributed among nodes independently of the accessed data. This approach is relatively expensive because all nodes must store all data and apply all data modifications caused by inserts, deletes, or updates. In contrast to full replication, partial replication is a more cost-efficient implementation: Instead of duplicating all data to all replica nodes, partial replicas store only a subset of the data while being able to process a large workload share. Besides lower storage costs, partial replicas enable (i) better scaling because replicas must potentially synchronize only subsets of the data modifications and thus have more capacity for read-only queries and (ii) better elasticity because replicas have to load less data and can be set up faster. However, splitting the overall workload evenly among the replica nodes while optimizing the data allocation is a challenging assignment problem. The calculation of optimized data allocations in a partially replicated database cluster can be modeled using integer linear programming (ILP). ILP is a common approach for solving assignment problems, also in the context of database systems. Because ILP is not scalable, existing approaches (also for calculating partial allocations) often fall back to simple (e.g., greedy) heuristics for larger problem instances. Simple heuristics may work well but can lose optimization potential. In this thesis, we present optimal and ILP-based heuristic programming models for calculating data fragment allocations for partially replicated database clusters. Using ILP, we are flexible to extend our models to (i) consider data modifications and reallocations and (ii) increase the robustness of allocations to compensate for node failures and workload uncertainty. We evaluate our approaches for TPC-H, TPC-DS, and a real-world accounting workload and compare the results to state-of-the-art allocation approaches. Our evaluations show significant improvements for varied allocation’s properties: Compared to existing approaches, we can, for example, (i) almost halve the amount of allocated data, (ii) improve the throughput in case of node failures and workload uncertainty while using even less memory, (iii) halve the costs of data modifications, and (iv) reallocate less than 90% of data when adding a node to the cluster. Importantly, we can calculate the corresponding ILP-based heuristic solutions within a few seconds. Finally, we demonstrate that the ideas of our ILP-based heuristics are also applicable to the index selection problem. N2 - Spaltenorientierte Datenbanksysteme können transaktionale und analytische Abfragen effizient auf einem einzigen Rechenknoten verarbeiten. Steigende Lasten oder Lastspitzen können Datenbanksysteme mit nur einem Rechenknoten jedoch schnell überlasten. Dann besteht eine gängige Skalierungsmöglichkeit darin, einen Datenbankcluster mit einem einzigen Rechenknoten für die Transaktionsverarbeitung und Replikatknoten für lesende Datenbankanfragen zu verwenden. Bei der (naiven) vollständigen Replikation werden Anfragen unabhängig von den Daten, auf die zugegriffen wird, auf die Knoten verteilt. Dieser Ansatz ist relativ teuer, da alle Knoten alle Daten speichern und alle Datenänderungen anwenden müssen, die durch das Einfügen, Löschen oder Aktualisieren von Datenbankeinträgen verursacht werden. Im Gegensatz zur vollständigen Replikation ist die partielle Replikation eine kostengünstige Alternative: Anstatt alle Daten auf alle Replikationsknoten zu duplizieren, speichern partielle Replikate nur eine Teilmenge der Daten und können gleichzeitig einen großen Anteil der Anfragelast verarbeiten. Neben niedrigeren Speicherkosten ermöglichen partielle Replikate (i) eine bessere Skalierung, da Replikate potenziell nur Teilmengen der Datenänderungen synchronisieren müssen und somit mehr Kapazität für lesende Anfragen haben, und (ii) eine bessere Elastizität, da Replikate weniger Daten laden müssen und daher schneller eingesetzt werden können. Die gleichmäßige Lastbalancierung auf die Replikatknoten bei gleichzeitiger Optimierung der Datenzuweisung ist jedoch ein schwieriges Zuordnungsproblem. Die Berechnung einer optimierten Datenverteilung in einem Datenbankcluster mit partiellen Replikaten kann mithilfe der ganzzahligen linearen Optimierung (engl. integer linear programming, ILP) durchgeführt werden. ILP ist ein gängiger Ansatz zur Lösung von Zuordnungsproblemen, auch im Kontext von Datenbanksystemen. Da ILP nicht skalierbar ist, greifen bestehende Ansätze (auch zur Berechnung von partiellen Replikationen) für größere Probleminstanzen oft auf einfache Heuristiken (z.B. Greedy-Algorithmen) zurück. Einfache Heuristiken können gut funktionieren, aber auch Optimierungspotenzial einbüßen. In dieser Arbeit stellen wir optimale und ILP-basierte heuristische Ansätze zur Berechnung von Datenzuweisungen für partiell-replizierte Datenbankcluster vor. Mithilfe von ILP können wir unsere Ansätze flexibel erweitern, um (i) Datenänderungen und -umverteilungen zu berücksichtigen und (ii) die Robustheit von Zuweisungen zu erhöhen, um Knotenausfälle und Unsicherheiten bezüglich der Anfragelast zu kompensieren. Wir evaluieren unsere Ansätze für TPC-H, TPC-DS und eine reale Buchhaltungsanfragelast und vergleichen die Ergebnisse mit herkömmlichen Verteilungsansätzen. Unsere Auswertungen zeigen signifikante Verbesserungen für verschiedene Eigenschaften der berechneten Datenzuordnungen: Im Vergleich zu bestehenden Ansätzen können wir beispielsweise (i) die Menge der gespeicherten Daten in Cluster fast halbieren, (ii) den Anfragedurchsatz bei Knotenausfällen und unsicherer Anfragelast verbessern und benötigen dafür auch noch weniger Speicher, (iii) die Kosten von Datenänderungen halbieren, und (iv) weniger als 90 % der Daten umverteilen, wenn ein Rechenknoten zum Cluster hinzugefügt wird. Wichtig ist, dass wir die entsprechenden ILP-basierten heuristischen Lösungen innerhalb weniger Sekunden berechnen können. Schließlich demonstrieren wir, dass die Ideen von unseren ILP-basierten Heuristiken auch auf das Indexauswahlproblem anwendbar sind. KW - database systems KW - integer linear programming KW - partial replication KW - index selection KW - load balancing KW - Datenbanksysteme KW - Indexauswahl KW - ganzzahlige lineare Optimierung KW - Lastverteilung KW - partielle Replikation Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-633615 ER - TY - JOUR A1 - Bläsius, Thomas A1 - Friedrich, Tobias A1 - Lischeid, Julius A1 - Meeks, Kitty A1 - Schirneck, Friedrich Martin T1 - Efficiently enumerating hitting sets of hypergraphs arising in data profiling JF - Journal of computer and system sciences : JCSS N2 - The transversal hypergraph problem asks to enumerate the minimal hitting sets of a hypergraph. If the solutions have bounded size, Eiter and Gottlob [SICOMP'95] gave an algorithm running in output-polynomial time, but whose space requirement also scales with the output. We improve this to polynomial delay and space. Central to our approach is the extension problem, deciding for a set X of vertices whether it is contained in any minimal hitting set. We show that this is one of the first natural problems to be W[3]-complete. We give an algorithm for the extension problem running in time O(m(vertical bar X vertical bar+1) n) and prove a SETH-lower bound showing that this is close to optimal. We apply our enumeration method to the discovery problem of minimal unique column combinations from data profiling. Our empirical evaluation suggests that the algorithm outperforms its worst-case guarantees on hypergraphs stemming from real-world databases. KW - Data profiling KW - Enumeration algorithm KW - Minimal hitting set KW - Transversal hypergraph KW - Unique column combination KW - W[3]-Completeness Y1 - 2022 U6 - https://doi.org/10.1016/j.jcss.2021.10.002 SN - 0022-0000 SN - 1090-2724 VL - 124 SP - 192 EP - 213 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Schlosser, Rainer A1 - Chenavaz, Régis Y. A1 - Dimitrov, Stanko T1 - Circular economy BT - joint dynamic pricing and recycling investments JF - International journal of production economics N2 - In a circular economy, the use of recycled resources in production is a key performance indicator for management. Yet, academic studies are still unable to inform managers on appropriate recycling and pricing policies. We develop an optimal control model integrating a firm's recycling rate, which can use both virgin and recycled resources in the production process. Our model accounts for recycling influence both at the supply- and demandsides. The positive effect of a firm's use of recycled resources diminishes over time but may increase through investments. Using general formulations for demand and cost, we analytically examine joint dynamic pricing and recycling investment policies in order to determine their optimal interplay over time. We provide numerical experiments to assess the existence of a steady-state and to calculate sensitivity analyses with respect to various model parameters. The analysis shows how to dynamically adapt jointly optimized controls to reach sustainability in the production process. Our results pave the way to sounder sustainable practices for firms operating within a circular economy. KW - Dynamic pricing KW - Recycling investments KW - Optimal control KW - General demand function KW - Circular economy Y1 - 2021 U6 - https://doi.org/10.1016/j.ijpe.2021.108117 SN - 0925-5273 SN - 1873-7579 VL - 236 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Thienen, Julia von A1 - Weinstein, Theresa Julia A1 - Meinel, Christoph T1 - Creative metacognition in design thinking BT - exploring theories, educational practices, and their implications for measurement JF - Frontiers in psychology N2 - Design thinking is a well-established practical and educational approach to fostering high-level creativity and innovation, which has been refined since the 1950s with the participation of experts like Joy Paul Guilford and Abraham Maslow. Through real-world projects, trainees learn to optimize their creative outcomes by developing and practicing creative cognition and metacognition. This paper provides a holistic perspective on creativity, enabling the formulation of a comprehensive theoretical framework of creative metacognition. It focuses on the design thinking approach to creativity and explores the role of metacognition in four areas of creativity expertise: Products, Processes, People, and Places. The analysis includes task-outcome relationships (product metacognition), the monitoring of strategy effectiveness (process metacognition), an understanding of individual or group strengths and weaknesses (people metacognition), and an examination of the mutual impact between environments and creativity (place metacognition). It also reviews measures taken in design thinking education, including a distribution of cognition and metacognition, to support students in their development of creative mastery. On these grounds, we propose extended methods for measuring creative metacognition with the goal of enhancing comprehensive assessments of the phenomenon. Proposed methodological advancements include accuracy sub-scales, experimental tasks where examinees explore problem and solution spaces, combinations of naturalistic observations with capability testing, as well as physiological assessments as indirect measures of creative metacognition. KW - accuracy KW - creativity KW - design thinking KW - education KW - measurement KW - metacognition KW - innovation KW - framework Y1 - 2023 U6 - https://doi.org/10.3389/fpsyg.2023.1157001 SN - 1664-1078 VL - 14 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Belaid, Mohamed Karim A1 - Rabus, Maximilian A1 - Krestel, Ralf T1 - CrashNet BT - an encoder-decoder architecture to predict crash test outcomes JF - Data mining and knowledge discovery N2 - Destructive car crash tests are an elaborate, time-consuming, and expensive necessity of the automotive development process. Today, finite element method (FEM) simulations are used to reduce costs by simulating car crashes computationally. We propose CrashNet, an encoder-decoder deep neural network architecture that reduces costs further and models specific outcomes of car crashes very accurately. We achieve this by formulating car crash events as time series prediction enriched with a set of scalar features. Traditional sequence-to-sequence models are usually composed of convolutional neural network (CNN) and CNN transpose layers. We propose to concatenate those with an MLP capable of learning how to inject the given scalars into the output time series. In addition, we replace the CNN transpose with 2D CNN transpose layers in order to force the model to process the hidden state of the set of scalars as one time series. The proposed CrashNet model can be trained efficiently and is able to process scalars and time series as input in order to infer the results of crash tests. CrashNet produces results faster and at a lower cost compared to destructive tests and FEM simulations. Moreover, it represents a novel approach in the car safety management domain. KW - Predictive models KW - Time series analysis KW - Supervised deep neural KW - networks KW - Car safety management Y1 - 2021 U6 - https://doi.org/10.1007/s10618-021-00761-9 SN - 1384-5810 SN - 1573-756X VL - 35 IS - 4 SP - 1688 EP - 1709 PB - Springer CY - Dordrecht ER - TY - GEN A1 - Benson, Lawrence A1 - Makait, Hendrik A1 - Rabl, Tilmann T1 - Viper BT - An Efficient Hybrid PMem-DRAM Key-Value Store T2 - Zweitveröffentlichungen der Universität Potsdam : Reihe der Digital Engineering Fakultät N2 - Key-value stores (KVSs) have found wide application in modern software systems. For persistence, their data resides in slow secondary storage, which requires KVSs to employ various techniques to increase their read and write performance from and to the underlying medium. Emerging persistent memory (PMem) technologies offer data persistence at close-to-DRAM speed, making them a promising alternative to classical disk-based storage. However, simply drop-in replacing existing storage with PMem does not yield good results, as block-based access behaves differently in PMem than on disk and ignores PMem's byte addressability, layout, and unique performance characteristics. In this paper, we propose three PMem-specific access patterns and implement them in a hybrid PMem-DRAM KVS called Viper. We employ a DRAM-based hash index and a PMem-aware storage layout to utilize the random-write speed of DRAM and efficient sequential-write performance PMem. Our evaluation shows that Viper significantly outperforms existing KVSs for core KVS operations while providing full data persistence. Moreover, Viper outperforms existing PMem-only, hybrid, and disk-based KVSs by 4-18x for write workloads, while matching or surpassing their get performance. T3 - Zweitveröffentlichungen der Universität Potsdam : Reihe der Digital Engineering Fakultät - 20 KW - memory Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-559664 SN - 2150-8097 IS - 9 ER - TY - GEN A1 - Kruse, Sebastian A1 - Kaoudi, Zoi A1 - Contreras-Rojas, Bertty A1 - Chawla, Sanjay A1 - Naumann, Felix A1 - Quiané-Ruiz, Jorge-Arnulfo T1 - RHEEMix in the data jungle BT - a cost-based optimizer for cross-platform systems T2 - Zweitveröffentlichungen der Universität Potsdam : Reihe der Digital Engineering Fakultät N2 - Data analytics are moving beyond the limits of a single platform. In this paper, we present the cost-based optimizer of Rheem, an open-source cross-platform system that copes with these new requirements. The optimizer allocates the subtasks of data analytic tasks to the most suitable platforms. Our main contributions are: (i) a mechanism based on graph transformations to explore alternative execution strategies; (ii) a novel graph-based approach to determine efficient data movement plans among subtasks and platforms; and (iii) an efficient plan enumeration algorithm, based on a novel enumeration algebra. We extensively evaluate our optimizer under diverse real tasks. We show that our optimizer can perform tasks more than one order of magnitude faster when using multiple platforms than when using a single platform. T3 - Zweitveröffentlichungen der Universität Potsdam : Reihe der Digital Engineering Fakultät - 22 KW - cross-platform KW - polystore KW - query optimization KW - data processing Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-519443 IS - 6 ER - TY - THES A1 - Limberger, Daniel T1 - Concepts and techniques for 3D-embedded treemaps and their application to software visualization T1 - Konzepte und Techniken für 3D-eingebettete Treemaps und ihre Anwendung auf Softwarevisualisierung N2 - This thesis addresses concepts and techniques for interactive visualization of hierarchical data using treemaps. It explores (1) how treemaps can be embedded in 3D space to improve their information content and expressiveness, (2) how the readability of treemaps can be improved using level-of-detail and degree-of-interest techniques, and (3) how to design and implement a software framework for the real-time web-based rendering of treemaps embedded in 3D. With a particular emphasis on their application, use cases from software analytics are taken to test and evaluate the presented concepts and techniques. Concerning the first challenge, this thesis shows that a 3D attribute space offers enhanced possibilities for the visual mapping of data compared to classical 2D treemaps. In particular, embedding in 3D allows for improved implementation of visual variables (e.g., by sketchiness and color weaving), provision of new visual variables (e.g., by physically based materials and in situ templates), and integration of visual metaphors (e.g., by reference surfaces and renderings of natural phenomena) into the three-dimensional representation of treemaps. For the second challenge—the readability of an information visualization—the work shows that the generally higher visual clutter and increased cognitive load typically associated with three-dimensional information representations can be kept low in treemap-based representations of both small and large hierarchical datasets. By introducing an adaptive level-of-detail technique, we cannot only declutter the visualization results, thereby reducing cognitive load and mitigating occlusion problems, but also summarize and highlight relevant data. Furthermore, this approach facilitates automatic labeling, supports the emphasis on data outliers, and allows visual variables to be adjusted via degree-of-interest measures. The third challenge is addressed by developing a real-time rendering framework with WebGL and accumulative multi-frame rendering. The framework removes hardware constraints and graphics API requirements, reduces interaction response times, and simplifies high-quality rendering. At the same time, the implementation effort for a web-based deployment of treemaps is kept reasonable. The presented visualization concepts and techniques are applied and evaluated for use cases in software analysis. In this domain, data about software systems, especially about the state and evolution of the source code, does not have a descriptive appearance or natural geometric mapping, making information visualization a key technology here. In particular, software source code can be visualized with treemap-based approaches because of its inherently hierarchical structure. With treemaps embedded in 3D, we can create interactive software maps that visually map, software metrics, software developer activities, or information about the evolution of software systems alongside their hierarchical module structure. Discussions on remaining challenges and opportunities for future research for 3D-embedded treemaps and their applications conclude the thesis. N2 - Diese Doktorarbeit behandelt Konzepte und Techniken zur interaktiven Visualisierung hierarchischer Daten mit Hilfe von Treemaps. Sie untersucht (1), wie Treemaps im 3D-Raum eingebettet werden können, um ihre Informationsinhalte und Ausdrucksfähigkeit zu verbessern, (2) wie die Lesbarkeit von Treemaps durch Techniken wie Level-of-Detail und Degree-of-Interest verbessert werden kann, und (3) wie man ein Software-Framework für das Echtzeit-Rendering von Treemaps im 3D-Raum entwirft und implementiert. Dabei werden Anwendungsfälle aus der Software-Analyse besonders betont und zur Verprobung und Bewertung der Konzepte und Techniken verwendet. Hinsichtlich der ersten Herausforderung zeigt diese Arbeit, dass ein 3D-Attributraum im Vergleich zu klassischen 2D-Treemaps verbesserte Möglichkeiten für die visuelle Kartierung von Daten bietet. Insbesondere ermöglicht die Einbettung in 3D eine verbesserte Umsetzung von visuellen Variablen (z.B. durch Skizzenhaftigkeit und Farbverwebungen), die Bereitstellung neuer visueller Variablen (z.B. durch physikalisch basierte Materialien und In-situ-Vorlagen) und die Integration visueller Metaphern (z.B. durch Referenzflächen und Darstellungen natürlicher Phänomene) in die dreidimensionale Darstellung von Treemaps. Für die zweite Herausforderung – die Lesbarkeit von Informationsvisualisierungen – zeigt die Arbeit, dass die allgemein höhere visuelle Unübersichtlichkeit und die damit einhergehende, erhöhte kognitive Belastung, die typischerweise mit dreidimensionalen Informationsdarstellungen verbunden sind, in Treemap-basierten Darstellungen sowohl kleiner als auch großer hierarchischer Datensätze niedrig gehalten werden können. Durch die Einführung eines adaptiven Level-of-Detail-Verfahrens lassen sich nicht nur die Visualisierungsergebnisse übersichtlicher gestalten, die kognitive Belastung reduzieren und Verdeckungsprobleme verringern, sondern auch relevante Daten zusammenfassen und hervorheben. Darüber hinaus erleichtert dieser Ansatz eine automatische Beschriftung, unterstützt die Hervorhebung von Daten-Ausreißern und ermöglicht die Anpassung von visuellen Variablen über Degree-of-Interest-Maße. Die dritte Herausforderung wird durch die Entwicklung eines Echtzeit-Rendering-Frameworks mit WebGL und akkumulativem Multi-Frame-Rendering angegangen. Das Framework hebt mehrere Hardwarebeschränkungen und Anforderungen an die Grafik-API auf, verkürzt die Reaktionszeiten auf Interaktionen und vereinfacht qualitativ hochwertiges Rendering. Gleichzeitig wird der Implementierungsaufwand für einen webbasierten Einsatz von Treemaps geringgehalten. Die vorgestellten Visualisierungskonzepte und -techniken werden für Anwendungsfälle in der Softwareanalyse eingesetzt und evaluiert. In diesem Bereich haben Daten über Softwaresysteme, insbesondere über den Zustand und die Evolution des Quellcodes, keine anschauliche Erscheinung oder natürliche geometrische Zuordnung, so dass die Informationsvisualisierung hier eine Schlüsseltechnologie darstellt. Insbesondere Softwarequellcode kann aufgrund seiner inhärenten hierarchischen Struktur mit Hilfe von Treemap-basierten Ansätzen visualisiert werden. Mit in 3D-eingebetteten Treemaps können wir interaktive Softwarelagekarten erstellen, die z.B. Softwaremetriken, Aktivitäten von Softwareentwickler*innen und Informationen über die Evolution von Softwaresystemen in ihrer hierarchischen Modulstruktur abbilden und veranschaulichen. Diskussionen über verbleibende Herausforderungen und Möglichkeiten für zukünftige Forschung zu 3D-eingebetteten Treemaps und deren Anwendungen schließen die Arbeit ab. KW - treemaps KW - software visualization KW - software analytics KW - web-based rendering KW - degree-of-interest techniques KW - labeling KW - 3D-embedding KW - interactive visualization KW - progressive rendering KW - hierarchical data KW - 3D-Einbettung KW - Interessengrad-Techniken KW - hierarchische Daten KW - interaktive Visualisierung KW - Beschriftung KW - progressives Rendering KW - Softwareanalytik KW - Softwarevisualisierung KW - Treemaps KW - Web-basiertes Rendering Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-632014 ER - TY - CHAP A1 - Corazza, Giovanni Emanuele A1 - Thienen, Julia von ED - Glăveanu, Vlad Petre T1 - Invention T2 - The Palgrave encyclopedia of the possible N2 - This entry addresses invention from five different perspectives: (i) definition of the term, (ii) mechanisms underlying invention processes, (iii) (pre-)history of human inventions, (iv) intellectual property protection vs open innovation, and (v) case studies of great inventors. Regarding the definition, an invention is the outcome of a creative process taking place within a technological milieu, which is recognized as successful in terms of its effectiveness as an original technology. In the process of invention, a technological possibility becomes realized. Inventions are distinct from either discovery or innovation. In human creative processes, seven mechanisms of invention can be observed, yielding characteristic outcomes: (1) basic inventions, (2) invention branches, (3) invention combinations, (4) invention toolkits, (5) invention exaptations, (6) invention values, and (7) game-changing inventions. The development of humanity has been strongly shaped by inventions ever since early stone tools and the conception of agriculture. An “explosion of creativity” has been associated with Homo sapiens, and inventions in all fields of human endeavor have followed suit, engendering an exponential growth of cumulative culture. This culture development emerges essentially through a reuse of previous inventions, their revision, amendment and rededication. In sociocultural terms, humans have increasingly regulated processes of invention and invention-reuse through concepts such as intellectual property, patents, open innovation and licensing methods. Finally, three case studies of great inventors are considered: Edison, Marconi, and Montessori, next to a discussion of human invention processes as collaborative endeavors. KW - invention KW - creativity KW - invention mechanism KW - cumulative culture KW - technology KW - innovation KW - patent KW - open innovation Y1 - 2023 SN - 978-3-030-90912-3 SN - 978-3-030-90913-0 U6 - https://doi.org/10.1007/978-3-030-90913-0_14 SP - 806 EP - 814 PB - Springer International Publishing CY - Cham ER - TY - JOUR A1 - Hiort, Pauline A1 - Schlaffner, Christoph N. A1 - Steen, Judith A. A1 - Renard, Bernhard Y. A1 - Steen, Hanno T1 - multiFLEX-LF: a computational approach to quantify the modification stoichiometries in label-free proteomics data sets JF - Journal of proteome research N2 - In liquid-chromatography-tandem-mass-spectrometry-based proteomics, information about the presence and stoichiometry ofprotein modifications is not readily available. To overcome this problem,we developed multiFLEX-LF, a computational tool that builds uponFLEXIQuant, which detects modified peptide precursors and quantifiestheir modification extent by monitoring the differences between observedand expected intensities of the unmodified precursors. multiFLEX-LFrelies on robust linear regression to calculate the modification extent of agiven precursor relative to a within-study reference. multiFLEX-LF cananalyze entire label-free discovery proteomics data sets in a precursor-centric manner without preselecting a protein of interest. To analyzemodification dynamics and coregulated modifications, we hierarchicallyclustered the precursors of all proteins based on their computed relativemodification scores. We applied multiFLEX-LF to a data-independent-acquisition-based data set acquired using the anaphase-promoting complex/cyclosome (APC/C) isolated at various time pointsduring mitosis. The clustering of the precursors allows for identifying varying modification dynamics and ordering the modificationevents. Overall, multiFLEX-LF enables the fast identification of potentially differentially modified peptide precursors and thequantification of their differential modification extent in large data sets using a personal computer. Additionally, multiFLEX-LF candrive the large-scale investigation of the modification dynamics of peptide precursors in time-series and case-control studies.multiFLEX-LF is available athttps://gitlab.com/SteenOmicsLab/multiflex-lf. KW - bioinformatics tool KW - label-free quantification KW - LC-MS KW - MS KW - post-translational modification KW - modification stoichiometry KW - PTM KW - quantification Y1 - 2022 U6 - https://doi.org/10.1021/acs.jproteome.1c00669 SN - 1535-3893 SN - 1535-3907 VL - 21 IS - 4 SP - 899 EP - 909 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Wittig, Alice A1 - Miranda, Fabio Malcher A1 - Hölzer, Martin A1 - Altenburg, Tom A1 - Bartoszewicz, Jakub Maciej A1 - Beyvers, Sebastian A1 - Dieckmann, Marius Alfred A1 - Genske, Ulrich A1 - Giese, Sven Hans-Joachim A1 - Nowicka, Melania A1 - Richard, Hugues A1 - Schiebenhoefer, Henning A1 - Schmachtenberg, Anna-Juliane A1 - Sieben, Paul A1 - Tang, Ming A1 - Tembrockhaus, Julius A1 - Renard, Bernhard Y. A1 - Fuchs, Stephan T1 - CovRadar BT - continuously tracking and filtering SARS-CoV-2 mutations for genomic surveillance JF - Bioinformatics N2 - The ongoing pandemic caused by SARS-CoV-2 emphasizes the importance of genomic surveillance to understand the evolution of the virus, to monitor the viral population, and plan epidemiological responses. Detailed analysis, easy visualization and intuitive filtering of the latest viral sequences are powerful for this purpose. We present CovRadar, a tool for genomic surveillance of the SARS-CoV-2 Spike protein. CovRadar consists of an analytical pipeline and a web application that enable the analysis and visualization of hundreds of thousand sequences. First, CovRadar extracts the regions of interest using local alignment, then builds a multiple sequence alignment, infers variants and consensus and finally presents the results in an interactive app, making accessing and reporting simple, flexible and fast. Y1 - 2022 U6 - https://doi.org/10.1093/bioinformatics/btac411 SN - 1367-4803 SN - 1367-4811 VL - 38 IS - 17 SP - 4223 EP - 4225 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Omolaoye, Temidayo S. A1 - Omolaoye, Victor Adelakun A1 - Kandasamy, Richard K. A1 - Hachim, Mahmood Yaseen A1 - Du Plessis, Stefan S. T1 - Omics and male infertility BT - highlighting the application of transcriptomic data JF - Life : open access journal N2 - Male infertility is a multifaceted disorder affecting approximately 50% of male partners in infertile couples. Over the years, male infertility has been diagnosed mainly through semen analysis, hormone evaluations, medical records and physical examinations, which of course are fundamental, but yet inefficient, because 30% of male infertility cases remain idiopathic. This dilemmatic status of the unknown needs to be addressed with more sophisticated and result-driven technologies and/or techniques. Genetic alterations have been linked with male infertility, thereby unveiling the practicality of investigating this disorder from the "omics" perspective. Omics aims at analyzing the structure and functions of a whole constituent of a given biological function at different levels, including the molecular gene level (genomics), transcript level (transcriptomics), protein level (proteomics) and metabolites level (metabolomics). In the current study, an overview of the four branches of omics and their roles in male infertility are briefly discussed; the potential usefulness of assessing transcriptomic data to understand this pathology is also elucidated. After assessing the publicly obtainable transcriptomic data for datasets on male infertility, a total of 1385 datasets were retrieved, of which 10 datasets met the inclusion criteria and were used for further analysis. These datasets were classified into groups according to the disease or cause of male infertility. The groups include non-obstructive azoospermia (NOA), obstructive azoospermia (OA), non-obstructive and obstructive azoospermia (NOA and OA), spermatogenic dysfunction, sperm dysfunction, and Y chromosome microdeletion. Findings revealed that 8 genes (LDHC, PDHA2, TNP1, TNP2, ODF1, ODF2, SPINK2, PCDHB3) were commonly differentially expressed between all disease groups. Likewise, 56 genes were common between NOA versus NOA and OA (ADAD1, BANF2, BCL2L14, C12orf50, C20orf173, C22orf23, C6orf99, C9orf131, C9orf24, CABS1, CAPZA3, CCDC187, CCDC54, CDKN3, CEP170, CFAP206, CRISP2, CT83, CXorf65, FAM209A, FAM71F1, FAM81B, GALNTL5, GTSF1, H1FNT, HEMGN, HMGB4, KIF2B, LDHC, LOC441601, LYZL2, ODF1, ODF2, PCDHB3, PDHA2, PGK2, PIH1D2, PLCZ1, PROCA1, RIMBP3, ROPN1L, SHCBP1L, SMCP, SPATA16, SPATA19, SPINK2, TEX33, TKTL2, TMCO2, TMCO5A, TNP1, TNP2, TSPAN16, TSSK1B, TTLL2, UBQLN3). These genes, particularly the above-mentioned 8 genes, are involved in diverse biological processes such as germ cell development, spermatid development, spermatid differentiation, regulation of proteolysis, spermatogenesis and metabolic processes. Owing to the stage-specific expression of these genes, any mal-expression can ultimately lead to male infertility. Therefore, currently available data on all branches of omics relating to male fertility can be used to identify biomarkers for diagnosing male infertility, which can potentially help in unravelling some idiopathic cases. KW - male infertility KW - omics KW - genomics KW - transcriptomics KW - proteomics KW - metabolomics Y1 - 2022 U6 - https://doi.org/10.3390/life12020280 SN - 2075-1729 VL - 12 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Gamage, Dilrukshi A1 - Staubitz, Thomas A1 - Whiting, Mark T1 - Peer assessment in MOOCs BT - Systematic literature review JF - Distance education N2 - We report on a systematic review of the landscape of peer assessment in massive open online courses (MOOCs) with papers from 2014 to 2020 in 20 leading education technology publication venues across four databases containing education technology-related papers, addressing three research issues: the evolution of peer assessment in MOOCs during the period 2014 to 2020, the methods used in MOOCs to assess peers, and the challenges of and future directions in MOOC peer assessment. We provide summary statistics and a review of methods across the corpus and highlight three directions for improving the use of peer assessment in MOOCs: the need for focusing on scaling learning through peer evaluations, the need for scaling and optimizing team submissions in team peer assessments, and the need for embedding a social process for peer assessment. KW - MOOC KW - peer assessment KW - peer evaluation KW - peer review KW - literature review KW - social interaction Y1 - 2021 U6 - https://doi.org/10.1080/01587919.2021.1911626 SN - 0158-7919 SN - 1475-0198 VL - 42 IS - 2 SP - 268 EP - 289 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Chandran, Sunil L. A1 - Issac, Davis A1 - Lauri, Juho A1 - van Leeuwen, Erik Jan T1 - Upper bounding rainbow connection number by forest number JF - Discrete mathematics N2 - A path in an edge-colored graph is rainbow if no two edges of it are colored the same, and the graph is rainbow-connected if there is a rainbow path between each pair of its vertices. The minimum number of colors needed to rainbow-connect a graph G is the rainbow connection number of G, denoted by rc(G).& nbsp;A simple way to rainbow-connect a graph G is to color the edges of a spanning tree with distinct colors and then re-use any of these colors to color the remaining edges of G. This proves that rc(G) <= |V (G)|-1. We ask whether there is a stronger connection between tree-like structures and rainbow coloring than that is implied by the above trivial argument. For instance, is it possible to find an upper bound of t(G)-1 for rc(G), where t(G) is the number of vertices in the largest induced tree of G? The answer turns out to be negative, as there are counter-examples that show that even c .t(G) is not an upper bound for rc(G) for any given constant c.& nbsp;In this work we show that if we consider the forest number f(G), the number of vertices in a maximum induced forest of G, instead of t(G), then surprisingly we do get an upper bound. More specifically, we prove that rc(G) <= f(G) + 2. Our result indicates a stronger connection between rainbow connection and tree-like structures than that was suggested by the simple spanning tree based upper bound. KW - rainbow connection KW - forest number KW - upper bound Y1 - 2022 U6 - https://doi.org/10.1016/j.disc.2022.112829 SN - 0012-365X SN - 1872-681X VL - 345 IS - 7 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Hölzle, Katharina A1 - Björk, Jennie A1 - Boer, Harry T1 - Light at the end of the tunnel JF - Creativity and innovation management Y1 - 2021 U6 - https://doi.org/10.1111/caim.12427 SN - 0963-1690 SN - 1467-8691 VL - 30 IS - 1 SP - 3 EP - 5 PB - Wiley-Blackwell CY - Oxford [u.a.] ER - TY - JOUR A1 - Navarro, Marisa A1 - Orejas, Fernando A1 - Pino, Elvira A1 - Lambers, Leen T1 - A navigational logic for reasoning about graph properties JF - Journal of logical and algebraic methods in programming N2 - Graphs play an important role in many areas of Computer Science. In particular, our work is motivated by model-driven software development and by graph databases. For this reason, it is very important to have the means to express and to reason about the properties that a given graph may satisfy. With this aim, in this paper we present a visual logic that allows us to describe graph properties, including navigational properties, i.e., properties about the paths in a graph. The logic is equipped with a deductive tableau method that we have proved to be sound and complete. KW - Graph logic KW - Algebraic methods KW - Formal modelling KW - Specification Y1 - 2021 U6 - https://doi.org/10.1016/j.jlamp.2020.100616 SN - 2352-2208 SN - 2352-2216 VL - 118 PB - Elsevier Science CY - Amsterdam [u.a.] ER - TY - JOUR A1 - de Paula, Danielly A1 - Marx, Carolin A1 - Wolf, Ella A1 - Dremel, Christian A1 - Cormican, Kathryn A1 - Uebernickel, Falk T1 - A managerial mental model to drive innovation in the context of digital transformation JF - Industry and innovation N2 - Industry 4.0 is transforming how businesses innovate and, as a result, companies are spearheading the movement towards 'Digital Transformation'. While some scholars advocate the use of design thinking to identify new innovative behaviours, cognition experts emphasise the importance of top managers in supporting employees to develop these behaviours. However, there is a dearth of research in this domain and companies are struggling to implement the required behaviours. To address this gap, this study aims to identify and prioritise behavioural strategies conducive to design thinking to inform the creation of a managerial mental model. We identify 20 behavioural strategies from 45 interviewees with practitioners and educators and combine them with the concepts of 'paradigm-mindset-mental model' from cognition theory. The paper contributes to the body of knowledge by identifying and prioritising specific behavioural strategies to form a novel set of survival conditions aligned to the new industrial paradigm of Industry 4.0. KW - Strategic cognition KW - mental models KW - industry 4.0 KW - digital transformation KW - design thinking Y1 - 2022 U6 - https://doi.org/10.1080/13662716.2022.2072711 SN - 1366-2716 SN - 1469-8390 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Ihde, Sven A1 - Pufahl, Luise A1 - Völker, Maximilian A1 - Goel, Asvin A1 - Weske, Mathias T1 - A framework for modeling and executing task BT - specific resource allocations in business processes JF - Computing : archives for informatics and numerical computation N2 - As resources are valuable assets, organizations have to decide which resources to allocate to business process tasks in a way that the process is executed not only effectively but also efficiently. Traditional role-based resource allocation leads to effective process executions, since each task is performed by a resource that has the required skills and competencies to do so. However, the resulting allocations are typically not as efficient as they could be, since optimization techniques have yet to find their way in traditional business process management scenarios. On the other hand, operations research provides a rich set of analytical methods for supporting problem-specific decisions on resource allocation. This paper provides a novel framework for creating transparency on existing tasks and resources, supporting individualized allocations for each activity in a process, and the possibility to integrate problem-specific analytical methods of the operations research domain. To validate the framework, the paper reports on the design and prototypical implementation of a software architecture, which extends a traditional process engine with a dedicated resource management component. This component allows us to define specific resource allocation problems at design time, and it also facilitates optimized resource allocation at run time. The framework is evaluated using a real-world parcel delivery process. The evaluation shows that the quality of the allocation results increase significantly with a technique from operations research in contrast to the traditional applied rule-based approach. KW - Process Execution KW - Business Process Management KW - Resource Allocation KW - Resource Management KW - Activity-oriented Optimization Y1 - 2022 U6 - https://doi.org/10.1007/s00607-022-01093-2 SN - 0010-485X SN - 1436-5057 VL - 104 SP - 2405 EP - 2429 PB - Springer CY - Wien ER - TY - JOUR A1 - Combi, Carlo A1 - Oliboni, Barbara A1 - Weske, Mathias A1 - Zerbato, Francesca T1 - Seamless conceptual modeling of processes with transactional and analytical data JF - Data & knowledge engineering N2 - In the field of Business Process Management (BPM), modeling business processes and related data is a critical issue since process activities need to manage data stored in databases. The connection between processes and data is usually handled at the implementation level, even if modeling both processes and data at the conceptual level should help designers in improving business process models and identifying requirements for implementation. Especially in data -and decision-intensive contexts, business process activities need to access data stored both in databases and data warehouses. In this paper, we complete our approach for defining a novel conceptual view that bridges process activities and data. The proposed approach allows the designer to model the connection between business processes and database models and define the operations to perform, providing interesting insights on the overall connected perspective and hints for identifying activities that are crucial for decision support. KW - Conceptual modeling KW - Business process modeling KW - BPMN KW - Data modeling KW - Data warehouse KW - Decision support Y1 - 2021 U6 - https://doi.org/10.1016/j.datak.2021.101895 SN - 0169-023X SN - 1872-6933 VL - 134 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Rüther, Ferenc Darius A1 - Sebode, Marcial A1 - Lohse, Ansgar W. A1 - Wernicke, Sarah A1 - Böttinger, Erwin A1 - Casar, Christian A1 - Braun, Felix A1 - Schramm, Christoph T1 - Mobile app requirements for patients with rare liver diseases BT - a single center survey for the ERN RARE-LIVER JF - Clinics and research in hepatology and gastroenterology N2 - Background: More patient data are needed to improve research on rare liver diseases. Mobile health apps enable an exhaustive data collection. Therefore, the European Reference Network on Hepatological diseases (ERN RARE-LIVER) intends to implement an app for patients with rare liver diseases communicating with a patient registry, but little is known about which features patients and their healthcare providers regard as being useful. Aims: This study aimed to investigate how an app for rare liver diseases would be accepted, and to find out which features are considered useful. Methods: An anonymous survey was conducted on adult patients with rare liver diseases at a single academic, tertiary care outpatient-service. Additionally, medical experts of the ERN working group on autoimmune hepatitis were invited to participate in an online survey. Results: In total, the responses from 100 patients with autoimmune (n = 90) or other rare (n = 10) liver diseases and 32 experts were analyzed. Patients were convinced to use a disease specific app (80%) and expected some benefit to their health (78%) but responses differed signifi-cantly between younger and older patients (93% vs. 62%, p < 0.001; 88% vs. 64%, p < 0.01). Comparing patients' and experts' feedback, patients more often expected a simplified healthcare pathway (e.g. 89% vs. 59% (p < 0.001) wanted access to one's own medical records), while healthcare providers saw the benefit mainly in improving compliance and treatment outcome (e.g. 93% vs. 31% (p < 0.001) and 70% vs. 21% (p < 0.001) expected the app to reduce mistakes in taking medication and improve quality of life, respectively). KW - Primary sclerosing cholangitis KW - Primary biliary cholangitis KW - Autoimmune KW - hepatitis KW - European reference networks KW - Mobile applications KW - Patient KW - reported out-come measures Y1 - 2021 U6 - https://doi.org/10.1016/j.clinre.2021.101760 SN - 2210-7401 SN - 2210-741X VL - 45 IS - 6 PB - Elsevier Masson CY - Amsterdam ER - TY - JOUR A1 - Koorn, Jelmer Jan A1 - Lu, Xixi A1 - Leopold, Henrik A1 - Reijers, Hajo A. T1 - From action to response to effect BT - mining statistical relations in work processes JF - Information systems : IS ; an international journal ; data bases N2 - Process mining techniques are valuable to gain insights into and help improve (work) processes. Many of these techniques focus on the sequential order in which activities are performed. Few of these techniques consider the statistical relations within processes. In particular, existing techniques do not allow insights into how responses to an event (action) result in desired or undesired outcomes (effects). We propose and formalize the ARE miner, a novel technique that allows us to analyze and understand these action-response-effect patterns. We take a statistical approach to uncover potential dependency relations in these patterns. The goal of this research is to generate processes that are: (1) appropriately represented, and (2) effectively filtered to show meaningful relations. We evaluate the ARE miner in two ways. First, we use an artificial data set to demonstrate the effectiveness of the ARE miner compared to two traditional process-oriented approaches. Second, we apply the ARE miner to a real-world data set from a Dutch healthcare institution. We show that the ARE miner generates comprehensible representations that lead to informative insights into statistical relations between actions, responses, and effects. KW - Process discovery KW - Statistical process mining KW - Effect measurement Y1 - 2022 U6 - https://doi.org/10.1016/j.is.2022.102035 SN - 0306-4379 SN - 0094-453X VL - 109 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Freitas da Cruz, Harry A1 - Pfahringer, Boris A1 - Martensen, Tom A1 - Schneider, Frederic A1 - Meyer, Alexander A1 - Böttinger, Erwin A1 - Schapranow, Matthieu-Patrick T1 - Using interpretability approaches to update "black-box" clinical prediction models BT - an external validation study in nephrology JF - Artificial intelligence in medicine : AIM N2 - Despite advances in machine learning-based clinical prediction models, only few of such models are actually deployed in clinical contexts. Among other reasons, this is due to a lack of validation studies. In this paper, we present and discuss the validation results of a machine learning model for the prediction of acute kidney injury in cardiac surgery patients initially developed on the MIMIC-III dataset when applied to an external cohort of an American research hospital. To help account for the performance differences observed, we utilized interpretability methods based on feature importance, which allowed experts to scrutinize model behavior both at the global and local level, making it possible to gain further insights into why it did not behave as expected on the validation cohort. The knowledge gleaned upon derivation can be potentially useful to assist model update during validation for more generalizable and simpler models. We argue that interpretability methods should be considered by practitioners as a further tool to help explain performance differences and inform model update in validation studies. KW - Clinical predictive modeling KW - Nephrology KW - Validation KW - Interpretability KW - methods Y1 - 2021 U6 - https://doi.org/10.1016/j.artmed.2020.101982 SN - 0933-3657 SN - 1873-2860 VL - 111 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Marx, Carolin Valerie T1 - Escalation of commitment in information systems projects: a cognitive-affective perspective T1 - Eskalation des Commitments in Wirtschaftsinformatik Projekten: eine kognitiv-affektive Perspektive N2 - While information systems (IS) projects are pivotal in guiding organizational strategies and sustaining competitive advantages, they frequently overrun budgets, extend beyond timelines, and experience high failure rates. This dissertation delves into the psychological micro-foundations of human behavior – specifically cognition and emotion – in relation to a prevalent issue in IS project management: the tendency to persist with failing courses of action, also called escalation of commitment (EoC). Through a mixed-methods research approach, this study investigates the emotional and cognitive bases of decision-making during IS project escalation and its evolution over time. The results of a psychophysiological laboratory experiment provide evidence for the predictions on the role of negative and complex situational integral emotions of Cognitive Dissonance over Coping Theory and add to a better understanding of how escalation tendencies change during sequential decision-making due to cognitive learning effects. Using psychophysiological measures, including data triangulation between electrodermal and cardiovascular activity and AI-based analysis of facial micro-expressions, this research reveals physiological markers of behavioral escalation tendencies. Complementing the experiment, a qualitative analysis using free-form narration during decision-making simulations shows that decision-makers employ varied cognitive reasoning patterns to justify escalating behaviors, suggesting a sequence of four distinct cognitive phases. By integrating both qualitative and quantitative findings, this dissertation offers a comprehensive theoretical framework of how cognition and emotion shape behavioral EoC over time. I propose that escalation is a cyclical adaptation of mental models, distinguished by shifts in cognitive reasoning patterns, temporal cognition mode variations, and interactions with situational emotions and their anticipation. The primary contribution of this dissertation lies in disentangling the emotional and cognitive mechanisms that drive IS project escalation. The findings provide the basis for developing de-escalation strategies, thereby helping to improve decision-making under uncertainty. Stakeholders involved in IS projects that get “off track” should be aware of the tendency to persist with failing courses of action and the importance of the underlying emotional and cognitive dynamics. N2 - Projekte im Bereich der Wirtschaftsinformatik (IS-Projekte) sind von zentraler Bedeutung für die Steuerung von Unternehmensstrategien und die Aufrechterhaltung von Wettbewerbsvorteilen, überschreiten jedoch häufig das Budget, sprengen den Zeitrahmen und weisen eine hohe Misserfolgsquote auf. Diese Dissertation befasst sich mit den psychologischen Grundlagen menschlichen Verhaltens - insbesondere Kognition und Emotion - im Zusammenhang mit einem weit verbreiteten Problem im IS-Projektmanagement: der Tendenz, an fehlgehenden Handlungssträngen festzuhalten, auch Eskalation des Commitments (Englisch: “escalation of commitment” - EoC) genannt. Mit einem kombinierten Forschungsansatz (dem Mix von qualitativen und quantitativen Methoden) untersuche ich in meiner Dissertation die emotionalen und kognitiven Grundlagen der Entscheidungsfindung hinter eskalierendem Commitment zu scheiternden IS-Projekten und deren Entwicklung über die Zeit. Die Ergebnisse eines psychophysiologischen Laborexperiments liefern Belege auf die Vorhersagen bezüglich der Rolle von negativen und komplexen situativen Emotionen der kognitiven Dissonanz Theorie gegenüber der Coping-Theorie und trägt zu einem besseren Verständnis dafür bei, wie sich Eskalationstendenzen während sequenzieller Entscheidungsfindung aufgrund kognitiver Lerneffekte verändern. Mit Hilfe psychophysiologischer Messungen, einschließlich der Daten-Triangulation zwischen elektrodermaler und kardiovaskulärer Aktivität sowie künstliche Intelligenz-basierter Analyse von Gesichtsmikroexpressionen, enthüllt diese Forschung physiologische Marker für eskalierendes Commitment. Ergänzend zu dem Experiment zeigt eine qualitative Analyse text-basierter Reflexionen während der Eskalationssituationen, dass Entscheidungsträger verschiedene kognitive Begründungsmuster verwenden, um eskalierende Verhaltensweisen zu rechtfertigen, die auf eine Sequenz von vier unterschiedlichen kognitiven Phasen schließen lassen. Durch die Integration von qualitativen und quantitativen Erkenntnissen entwickelt diese Dissertation ein umfassendes theoretisches Model dafür, wie Kognition und Emotion eskalierendes Commitment über die Zeit beeinflussen. Ich schlage vor, dass eskalierendes Commitment eine zyklische Anpassung von Denkmodellen ist, die sich durch Veränderungen in kognitiven Begründungsmustern, Variationen im zeitlichen Kognitionsmodus und Interaktionen mit situativen Emotionen und deren Erwartung auszeichnet. Der Hauptbeitrag dieser Arbeit liegt in der Entflechtung der emotionalen und kognitiven Mechanismen, die eskalierendes Commitment im Kontext von IS-Projekten antreiben. Die Erkenntnisse tragen dazu bei, die Qualität von Entscheidungen unter Unsicherheit zu verbessern und liefern die Grundlage für die Entwicklung von Deeskalationsstrategien. Beteiligte an „in Schieflage geratenden“ IS-Projekten sollten sich der Tendenz auf fehlgeschlagenen Aktionen zu beharren und der Bedeutung der zugrundeliegenden emotionalen und kognitiven Dynamiken bewusst sein. KW - information systems projects KW - escalation of commitment KW - emotional cognitive dynamics KW - emotional kognitive Dynamiken KW - eskalierendes Commitment KW - Wirtschaftsinformatik Projekte Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-626969 ER - TY - THES A1 - Alhosseini Almodarresi Yasin, Seyed Ali T1 - Classification, prediction and evaluation of graph neural networks on online social media platforms T1 - Klassifizierung, Vorhersage und Bewertung graphischer neuronaler Netze auf Online-Social-Media-Plattformen N2 - The vast amount of data generated on social media platforms have made them a valuable source of information for businesses, governments and researchers. Social media data can provide insights into user behavior, preferences, and opinions. In this work, we address two important challenges in social media analytics. Predicting user engagement with online content has become a critical task for content creators to increase user engagement and reach larger audiences. Traditional user engagement prediction approaches rely solely on features derived from the user and content. However, a new class of deep learning methods based on graphs captures not only the content features but also the graph structure of social media networks. This thesis proposes a novel Graph Neural Network (GNN) approach to predict user interaction with tweets. The proposed approach combines the features of users, tweets and their engagement graphs. The tweet text features are extracted using pre-trained embeddings from language models, and a GNN layer is used to embed the user in a vector space. The GNN model then combines the features and graph structure to predict user engagement. The proposed approach achieves an accuracy value of 94.22% in classifying user interactions, including likes, retweets, replies, and quotes. Another major challenge in social media analysis is detecting and classifying social bot accounts. Social bots are automated accounts used to manipulate public opinion by spreading misinformation or generating fake interactions. Detecting social bots is critical to prevent their negative impact on public opinion and trust in social media. In this thesis, we classify social bots on Twitter by applying Graph Neural Networks. The proposed approach uses a combination of both the features of a node and an aggregation of the features of a node’s neighborhood to classify social bot accounts. Our final results indicate a 6% improvement in the area under the curve score in the final predictions through the utilization of GNN. Overall, our work highlights the importance of social media data and the potential of new methods such as GNNs to predict user engagement and detect social bots. These methods have important implications for improving the quality and reliability of information on social media platforms and mitigating the negative impact of social bots on public opinion and discourse. N2 - Die riesige Menge an Daten, die auf Social-Media-Plattformen generiert wird, hat sie zu einer wertvollen Informationsquelle für Unternehmen, Regierungen und Forscher gemacht. Daten aus sozialen Medien können Einblicke in das Verhalten, die Vorlieben und die Meinungen der Nutzer geben. In dieser Arbeit befassen wir uns mit zwei wichtigen Herausforderungen im Bereich der Social-Media-Analytik. Die Vorhersage des Nutzerinteresses an Online-Inhalten ist zu einer wichtigen Aufgabe für die Ersteller von Inhalten geworden, um das Nutzerengagement zu steigern und ein größeres Publikum zu erreichen. Herkömmliche Ansätze zur Vorhersage des Nutzerengagements stützen sich ausschließlich auf Merkmale, die aus dem Nutzer und dem Inhalt abgeleitet werden. Eine neue Klasse von Deep-Learning-Methoden, die auf Graphen basieren, erfasst jedoch nicht nur die Inhaltsmerkmale, sondern auch die Graphenstruktur von Social-Media-Netzwerken. In dieser Arbeit wird ein neuartiger Graph Neural Network (GNN)-Ansatz zur Vorhersage der Nutzerinteraktion mit Tweets vorgeschlagen. Der vorgeschlagene Ansatz kombiniert die Merkmale von Nutzern, Tweets und deren Engagement-Graphen. Die Textmerkmale der Tweets werden mit Hilfe von vortrainierten Einbettungen aus Sprachmodellen extrahiert, und eine GNN-Schicht wird zur Einbettung des Nutzers in einen Vektorraum verwendet. Das GNN-Modell kombiniert dann die Merkmale und die Graphenstruktur, um das Nutzerengagement vorherzusagen. Der vorgeschlagene Ansatz erreicht eine Genauigkeit von 94,22% bei der Klassifizierung von Benutzerinteraktionen, einschließlich Likes, Retweets, Antworten und Zitaten. Eine weitere große Herausforderung bei der Analyse sozialer Medien ist die Erkennung und Klassifizierung von Social-Bot-Konten. Social Bots sind automatisierte Konten, die dazu dienen, die öffentliche Meinung zu manipulieren, indem sie Fehlinformationen verbreiten oder gefälschte Interaktionen erzeugen. Die Erkennung von Social Bots ist entscheidend, um ihre negativen Auswirkungen auf die öffentliche Meinung und das Vertrauen in soziale Medien zu verhindern. In dieser Arbeit klassifizieren wir Social Bots auf Twitter mit Hilfe von Graph Neural Networks. Der vorgeschlagene Ansatz verwendet eine Kombination aus den Merkmalen eines Knotens und einer Aggregation der Merkmale der Nachbarschaft eines Knotens, um Social-Bot-Konten zu klassifizieren. Unsere Endergebnisse zeigen eine 6%ige Verbesserung der Fläche unter der Kurve bei den endgültigen Vorhersagen durch die Verwendung von GNN. Insgesamt unterstreicht unsere Arbeit die Bedeutung von Social-Media-Daten und das Potenzial neuer Methoden wie GNNs zur Vorhersage des Nutzer-Engagements und zur Erkennung von Social Bots. Diese Methoden haben wichtige Auswirkungen auf die Verbesserung der Qualität und Zuverlässigkeit von Informationen auf Social-Media-Plattformen und die Abschwächung der negativen Auswirkungen von Social Bots auf die öffentliche Meinung und den Diskurs. KW - graph neural networks KW - social bot detection KW - user engagement KW - graphische neuronale Netze KW - Social Bots erkennen KW - Nutzer-Engagement Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-626421 ER - TY - JOUR A1 - Aa, Han van der A1 - Rebmann, Adrian A1 - Leopold, Henrik T1 - Natural language-based detection of semantic execution anomalies in event logs JF - Information systems : IS ; an international journal ; data bases N2 - Anomaly detection in process mining aims to recognize outlying or unexpected behavior in event logs for purposes such as the removal of noise and identification of conformance violations. Existing techniques for this task are primarily frequency-based, arguing that behavior is anomalous because it is uncommon. However, such techniques ignore the semantics of recorded events and, therefore, do not take the meaning of potential anomalies into consideration. In this work, we overcome this caveat and focus on the detection of anomalies from a semantic perspective, arguing that anomalies can be recognized when process behavior does not make sense. To achieve this, we propose an approach that exploits the natural language associated with events. Our key idea is to detect anomalous process behavior by identifying semantically inconsistent execution patterns. To detect such patterns, we first automatically extract business objects and actions from the textual labels of events. We then compare these against a process-independent knowledge base. By populating this knowledge base with patterns from various kinds of resources, our approach can be used in a range of contexts and domains. We demonstrate the capability of our approach to successfully detect semantic execution anomalies through an evaluation based on a set of real-world and synthetic event logs and show the complementary nature of semantics-based anomaly detection to existing frequency-based techniques. KW - Process mining KW - Natural language processing KW - Anomaly detection Y1 - 2021 U6 - https://doi.org/10.1016/j.is.2021.101824 SN - 0306-4379 SN - 1873-6076 VL - 102 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Benson, Lawrence T1 - Efficient state management with persistent memory N2 - Efficiently managing large state is a key challenge for data management systems. Traditionally, state is split into fast but volatile state in memory for processing and persistent but slow state on secondary storage for durability. Persistent memory (PMem), as a new technology in the storage hierarchy, blurs the lines between these states by offering both byte-addressability and low latency like DRAM as well persistence like secondary storage. These characteristics have the potential to cause a major performance shift in database systems. Driven by the potential impact that PMem has on data management systems, in this thesis we explore their use of PMem. We first evaluate the performance of real PMem hardware in the form of Intel Optane in a wide range of setups. To this end, we propose PerMA-Bench, a configurable benchmark framework that allows users to evaluate the performance of customizable database-related PMem access. Based on experimental results obtained with PerMA-Bench, we discuss findings and identify general and implementation-specific aspects that influence PMem performance and should be considered in future work to improve PMem-aware designs. We then propose Viper, a hybrid PMem-DRAM key-value store. Based on PMem-aware access patterns, we show how to leverage PMem and DRAM efficiently to design a key database component. Our evaluation shows that Viper outperforms existing key-value stores by 4–18x for inserts while offering full data persistence and achieving similar or better lookup performance. Next, we show which changes must be made to integrate PMem components into larger systems. By the example of stream processing engines, we highlight limitations of current designs and propose a prototype engine that overcomes these limitations. This allows our prototype to fully leverage PMem's performance for its internal state management. Finally, in light of Optane's discontinuation, we discuss how insights from PMem research can be transferred to future multi-tier memory setups by the example of Compute Express Link (CXL). Overall, we show that PMem offers high performance for state management, bridging the gap between fast but volatile DRAM and persistent but slow secondary storage. Although Optane was discontinued, new memory technologies are continuously emerging in various forms and we outline how novel designs for them can build on insights from existing PMem research. N2 - Die effiziente Verwaltung großer Zustände ist eine zentrale Herausforderung für Datenverwaltungssysteme. Traditionell wird der Zustand in einen schnellen, aber flüchtigen Zustand im Speicher für die Verarbeitung und einen persistenten, aber langsamen Zustand im Sekundärspeicher für die Speicherung unterteilt. Persistenter Speicher (PMem), eine neue Technologie in der Speicherhierarchie, lässt die Grenzen zwischen diesen Zuständen verschwimmen, indem er sowohl Byte-Adressierbarkeit und geringe Latenz wie DRAM als auch Persistenz wie Sekundärspeicher bietet. Diese Eigenschaften haben das Potenzial, die Leistung von Datenbanksystemen grundlegend zu verändern. Aufgrund der potenziellen Auswirkungen, die PMem auf Datenverwaltungssysteme hat, untersuchen wir in dieser Arbeit ihre Verwendung von PMem. Zunächst evaluieren wir die Leistung von echter PMem-Hardware in Form von Intel Optane in einer Vielzahl von Konfigurationen. Zu diesem Zweck stellen wir PerMA-Bench vor, ein konfigurierbares Benchmark-Framework, mit dem Benutzer die Leistung von anpassbaren datenbankbezogenen PMem-Zugriffen untersuchen können. Auf der Grundlage der mit PerMA-Bench erzielten experimentellen Ergebnisse diskutieren wir unsere Erkenntnisse und identifizieren allgemeine und implementierungsspezifische Aspekte, die die PMem-Leistung beeinflussen und in zukünftigen Arbeiten berücksichtigt werden sollten, um PMem-fähige Designs zu verbessern. Anschließend präsentieren wir Viper, einen hybriden PMem-DRAM Key-Value-Store. Basierend auf PMem-bewussten Zugriffsmustern zeigen wir, wie PMem und DRAM effizient genutzt werden können, um eine wichtige Datenbankkomponente zu entwickeln. Unsere Evaluierung zeigt, dass Viper bestehende Key-Value-Stores bei Einfügungen um 4- bis 18-mal übertrifft, während er gleichzeitig vollständige Datenpersistenz bietet und ähnliche oder bessere Lookup-Leistung erzielt. Als nächstes zeigen wir, welche Änderungen vorgenommen werden müssen, um PMem-Komponenten in größere Systeme zu integrieren. Am Beispiel von Datenstromverarbeitungssystemen zeigen wir die Einschränkungen aktueller Designs auf und stellen einen Prototyp eines Systems vor, das diese Einschränkungen überwindet. Dadurch kann unser Prototyp die Leistung von PMem für die interne Zustandsverwaltung voll ausnutzen. Schließlich erörtern wir angesichts der Abkündigung von Optane, wie Erkenntnisse aus der PMem-Forschung am Beispiel von Compute Express Link (CXL) auf künftige mehrstufige Speicher-Setups übertragen werden können. Insgesamt zeigen wir, dass PMem eine hohe Leistungsfähigkeit für die Zustandsverwaltung bietet und die Lücke zwischen schnellem, aber flüchtigem DRAM und beständigem, aber langsamem Sekundärspeicher schließt. Obwohl Optane eingestellt wurde, entstehen ständig neue Speichertechnologien in verschiedenen Formen, und wir skizzieren, wie neuartige Entwürfe für sie auf den Erkenntnissen aus der bestehenden PMem-Forschung aufbauen können. KW - persistent memory KW - pmem KW - database KW - data management KW - state management KW - Datenverwaltung KW - Datenbank KW - persistenter Speicher KW - pmem KW - Zustandsverwaltung Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-625637 ER - TY - THES A1 - Ghahremani, Sona T1 - Incremental self-adaptation of dynamic architectures attaining optimality and scalability T1 - Inkrementelle Selbstanpassung dynamischer Architekturen zum Erreichen von Optimalität und Skalierbarkeit N2 - The landscape of software self-adaptation is shaped in accordance with the need to cost-effectively achieve and maintain (software) quality at runtime and in the face of dynamic operation conditions. Optimization-based solutions perform an exhaustive search in the adaptation space, thus they may provide quality guarantees. However, these solutions render the attainment of optimal adaptation plans time-intensive, thereby hindering scalability. Conversely, deterministic rule-based solutions yield only sub-optimal adaptation decisions, as they are typically bound by design-time assumptions, yet they offer efficient processing and implementation, readability, expressivity of individual rules supporting early verification. Addressing the quality-cost trade-of requires solutions that simultaneously exhibit the scalability and cost-efficiency of rulebased policy formalism and the optimality of optimization-based policy formalism as explicit artifacts for adaptation. Utility functions, i.e., high-level specifications that capture system objectives, support the explicit treatment of quality-cost trade-off. Nevertheless, non-linearities, complex dynamic architectures, black-box models, and runtime uncertainty that makes the prior knowledge obsolete are a few of the sources of uncertainty and subjectivity that render the elicitation of utility non-trivial. This thesis proposes a twofold solution for incremental self-adaptation of dynamic architectures. First, we introduce Venus, a solution that combines in its design a ruleand an optimization-based formalism enabling optimal and scalable adaptation of dynamic architectures. Venus incorporates rule-like constructs and relies on utility theory for decision-making. Using a graph-based representation of the architecture, Venus captures rules as graph patterns that represent architectural fragments, thus enabling runtime extensibility and, in turn, support for dynamic architectures; the architecture is evaluated by assigning utility values to fragments; pattern-based definition of rules and utility enables incremental computation of changes on the utility that result from rule executions, rather than evaluating the complete architecture, which supports scalability. Second, we introduce HypeZon, a hybrid solution for runtime coordination of multiple off-the-shelf adaptation policies, which typically offer only partial satisfaction of the quality and cost requirements. Realized based on meta-self-aware architectures, HypeZon complements Venus by re-using existing policies at runtime for balancing the quality-cost trade-off. The twofold solution of this thesis is integrated in an adaptation engine that leverages state- and event-based principles for incremental execution, therefore, is scalable for large and dynamic software architectures with growing size and complexity. The utility elicitation challenge is resolved by defining a methodology to train utility-change prediction models. The thesis addresses the quality-cost trade-off in adaptation of dynamic software architectures via design-time combination (Venus) and runtime coordination (HypeZon) of rule- and optimization-based policy formalisms, while offering supporting mechanisms for optimal, cost-effective, scalable, and robust adaptation. The solutions are evaluated according to a methodology that is obtained based on our systematic literature review of evaluation in self-healing systems; the applicability and effectiveness of the contributions are demonstrated to go beyond the state-of-the-art in coverage of a wide spectrum of the problem space for software self-adaptation. N2 - Die Landschaft der Software-Selbstanpassungen ist von der Notwendigkeit geprägt, zur Laufzeit und angesichts dynamischer Betriebsbedingungen kosteneffizient (Software-)Qualität zu erreichen und aufrechtzuerhalten. Optimierungsbasierte Lösungen führen eine umfassende Suche im Anpassungsraum durch und können daher Qualitätsgarantien bieten. Allerdings machen diese Lösungen das Erreichen optimaler Anpassungspläne zeitintensiv und behindern dadurch die Skalierbarkeit. Umgekehrt führen deterministische regelbasierte Lösungen nur zu suboptimalen Anpassungsentscheidungen, da sie typischerweise an Annahmen zur Entwurfszeit gebunden sind. Sie bieten jedoch eine effiziente Verarbeitung und Implementierung, Lesbarkeit und Ausdruckskraft einzelner Regeln und unterstützen so eine frühzeitige Überprüfung der Korrektheit. Um den Kompromiss zwischen Qualität und Kosten anzugehen, sind Lösungen erforderlich, die gleichzeitig die Skalierbarkeit und Kosteneffizienz des regelbasierten Strategieformalismus und die Optimalität des optimierungsbasierten Strategieformalismus als explizite Artefakte für die Anpassung berücksichtigen. Utility-Funktionen, d.h. Spezifikationen auf abstrakter Ebene, die Systemziele erfassen, unterstützen die explizite Behandlung des Qualität-Kosten-Kompromisses. Dennoch sind Nichtlinearitäten, komplexe dynamische Architekturen, Black-Box-Modelle und Laufzeitunsicherheit, die das Vorwissen überflüssig macht, einige der Quellen von Unsicherheit und Subjektivität, die die Utility-Erhöhung nicht trivial machen. Diese Arbeit schlägt eine zweifältige Lösung für die inkrementelle Selbstanpassung dynamischer Architekturen vor. Zunächst stellen wir Venus vor, eine Lösung, die in ihrem Design einen regel- und optimierungsbasierten Formalismus kombiniert und so eine optimale und skalierbare Anpassung dynamischer Architekturen ermöglicht. Venus enthält regelartige Konstrukte und nutzt die Utility-Theorie für die Entscheidungsfindung. Mithilfe einer graphbasierten Darstellung der Architektur erfasst Venus Regeln als Graphmuster, die Architekturfragmente darstellen, und ermöglicht so die Erweiterbarkeit zur Laufzeit und damit die Unterstützung dynamischer Architekturen. Die Architektur wird bewertet, indem den Fragmenten Utility-Werte zugewiesen werden. Die graphbasierte Definition von Regeln und Utility ermöglicht die inkrementelle Berechnung von Änderungen der Utility, die sich aus Regelausführungen ergeben, anstatt die gesamte Architektur zu bewerten, was die Skalierbarkeit verbessert. Des weiteren stellen wir HypeZon vor, eine Hybridlösung zur Laufzeitkoordination mehrerer Standardanpassungsstrategien, die typischerweise nur eine partielle Erfüllung der Qualitäts- und Kostenanforderungen bieten. HypeZon wurde auf der Grundlage der meta-selbstwahrnehmenden Architekturen umgesetzt und ergänzt Venus durch die Wiederverwendung bestehender Strategien zur Laufzeit, um den Kompromiss zwischen Qualität und Kosten auszubalancieren. Die zweifältige Lösung aus dieser Dissertation ist in eine Anpassungs-Engine integriert, die zustands- und ereignisbasierte Prinzipien für die inkrementelle Ausführung nutzt und daher für große und dynamische Softwarearchitekturen mit wachsender Größe und Komplexität skalierbar ist. Die Herausforderung der Erhöhung der Utility wird durch die Definition einer Methodik gelöst, die zum Trainieren von Modellen zur Vorhersage von Utility-Änderungen verwendet wird. Die Dissertation befasst sich mit dem Qualität-Kosten-Kompromiss bei der Anpassung dynamischer Softwarearchitekturen durch Entwurfszeitkombination (Venus) und Laufzeitkoordination (HypeZon) von regel- und optimierungsbasierten Strategieformalismen und bietet gleichzeitig unterstützende Mechanismen für optimale, kosteneffektive, skalierbare und robuste Anpassung. Die Lösungen werden nach einer Methodik bewertet, die auf unserer systematischen Literaturrecherche zur Bewertung von selbstheilenden Systemen basiert. Die Anwendbarkeit und Wirksamkeit der Lösungen geht nachweislich über den Stand der Technik hinaus und deckt ein breites Spektrum des Problembereichs der Software-Selbstanpassung ab. KW - self-healing KW - self-adaptive systems KW - architecture-based software adaptation KW - utility functions KW - prediction models KW - meta self-adaptation KW - model-driven engineering KW - scalable KW - architekturbasierte Softwareanpassung KW - Meta-Selbstanpassung KW - modellgesteuerte Entwicklung KW - Vorhersagemodelle KW - skalierbar KW - selbstanpassende Systeme KW - selbstheilende Systeme KW - Utility-Funktionen Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624232 ER - TY - THES A1 - Vitagliano, Gerardo T1 - Modeling the structure of tabular files for data preparation T1 - Modellierung der Struktur von Tabellarische Dateien für die Datenaufbereitung N2 - To manage tabular data files and leverage their content in a given downstream task, practitioners often design and execute complex transformation pipelines to prepare them. The complexity of such pipelines stems from different factors, including the nature of the preparation tasks, often exploratory or ad-hoc to specific datasets; the large repertory of tools, algorithms, and frameworks that practitioners need to master; and the volume, variety, and velocity of the files to be prepared. Metadata plays a fundamental role in reducing this complexity: characterizing a file assists end users in the design of data preprocessing pipelines, and furthermore paves the way for suggestion, automation, and optimization of data preparation tasks. Previous research in the areas of data profiling, data integration, and data cleaning, has focused on extracting and characterizing metadata regarding the content of tabular data files, i.e., about the records and attributes of tables. Content metadata are useful for the latter stages of a preprocessing pipeline, e.g., error correction, duplicate detection, or value normalization, but they require a properly formed tabular input. Therefore, these metadata are not relevant for the early stages of a preparation pipeline, i.e., to correctly parse tables out of files. In this dissertation, we turn our focus to what we call the structure of a tabular data file, i.e., the set of characters within a file that do not represent data values but are required to parse and understand the content of the file. We provide three different approaches to represent file structure, an explicit representation based on context-free grammars; an implicit representation based on file-wise similarity; and a learned representation based on machine learning. In our first contribution, we use the grammar-based representation to characterize a set of over 3000 real-world csv files and identify multiple structural issues that let files deviate from the csv standard, e.g., by having inconsistent delimiters or containing multiple tables. We leverage our learnings about real-world files and propose Pollock, a benchmark to test how well systems parse csv files that have a non-standard structure, without any previous preparation. We report on our experiments on using Pollock to evaluate the performance of 16 real-world data management systems. Following, we characterize the structure of files implicitly, by defining a measure of structural similarity for file pairs. We design a novel algorithm to compute this measure, which is based on a graph representation of the files' content. We leverage this algorithm and propose Mondrian, a graphical system to assist users in identifying layout templates in a dataset, classes of files that have the same structure, and therefore can be prepared by applying the same preparation pipeline. Finally, we introduce MaGRiTTE, a novel architecture that uses self-supervised learning to automatically learn structural representations of files in the form of vectorial embeddings at three different levels: cell level, row level, and file level. We experiment with the application of structural embeddings for several tasks, namely dialect detection, row classification, and data preparation efforts estimation. Our experimental results show that structural metadata, either identified explicitly on parsing grammars, derived implicitly as file-wise similarity, or learned with the help of machine learning architectures, is fundamental to automate several tasks, to scale up preparation to large quantities of files, and to provide repeatable preparation pipelines. N2 - Anwender müssen häufig komplexe Pipelines zur Aufbereitung von tabellarischen Dateien entwerfen, um diese verwalten und ihre Inhalte für nachgelagerte Aufgaben nutzen zu können. Die Komplexität solcher Pipelines ergibt sich aus verschiedenen Faktoren, u.a. (i) aus der Art der Aufbereitungsaufgaben, die oft explorativ oder ad hoc für bestimmte Datensätze durchgeführt werden, (ii) aus dem großen Repertoire an Werkzeugen, Algorithmen und Frameworks, die von den Anwendern beherrscht werden müssen, sowie (iii) aus der Menge, der Größe und der Verschiedenartigkeit der aufzubereitenden Dateien. Metadaten spielen eine grundlegende Rolle bei der Verringerung dieser Komplexität: Die Charakterisierung einer Datei hilft den Nutzern bei der Gestaltung von Datenaufbereitungs-Pipelines und ebnet darüber hinaus den Weg für Vorschläge, Automatisierung und Optimierung von Datenaufbereitungsaufgaben. Bisherige Forschungsarbeiten in den Bereichen Data Profiling, Datenintegration und Datenbereinigung konzentrierten sich auf die Extraktion und Charakterisierung von Metadaten über die Inhalte der tabellarischen Dateien, d.h. über die Datensätze und Attribute von Tabellen. Inhalts-basierte Metadaten sind für die letzten Phasen einer Aufbereitungspipeline nützlich, z.B. für die Fehlerkorrektur, die Erkennung von Duplikaten oder die Normalisierung von Werten, aber sie erfordern eine korrekt geformte tabellarische Eingabe. Daher sind diese Metadaten für die frühen Phasen einer Aufbereitungspipeline, d.h. für das korrekte Parsen von Tabellen aus Dateien, nicht relevant. In dieser Dissertation konzentrieren wir uns die Struktur einer tabellarischen Datei nennen, d.h. die Menge der Zeichen in einer Datei, die keine Datenwerte darstellen, aber erforderlich sind, um den Inhalt der Datei zu analysieren und zu verstehen. Wir stellen drei verschiedene Ansätze zur Darstellung der Dateistruktur vor: eine explizite Darstellung auf der Grundlage kontextfreier Grammatiken, eine implizite Darstellung auf der Grundlage von Dateiähnlichkeiten und eine erlernte Darstellung auf der Grundlage von maschinellem Lernen. In unserem ersten Ansatz verwenden wir die grammatikbasierte Darstellung, um eine Menge von über 3000 realen CSV-Dateien zu charakterisieren und mehrere strukturelle Probleme zu identifizieren, die dazu führen, dass Dateien vom CSV-Standard abweichen, z.B. durch inkonsistente Begrenzungszeichen oder dem Enthalten mehrere Tabellen in einer einzelnen Datei. Wir nutzen unsere Erkenntnisse aus realen Dateien und schlagen Pollock vor, einen Benchmark, der testet, wie gut Systeme unaufbereitete CSV-Dateien parsen. Wir berichten über unsere Experimente zur Verwendung von Pollock, in denen wir die Leistung von 16 realen Datenverwaltungssystemen bewerten. Anschließend charakterisieren wir die Struktur von Dateien implizit, indem wir ein Maß für die strukturelle Ähnlichkeit von Dateipaaren definieren. Wir entwickeln einen neuartigen Algorithmus zur Berechnung dieses Maßes, der auf einer Graphen-basierten Darstellung des Dateiinhalts basiert. Wir nutzen diesen Algorithmus und schlagen Mondrian vor, ein grafisches System zur Unterstützung der Benutzer bei der Identifizierung von Layout Vorlagen in einem Datensatz, d.h. von Dateiklassen, die die gleiche Struktur aufweisen und daher mit der gleichen Pipeline aufbereitet werden können. Schließlich stellen wir MaGRiTTE vor, eine neuartige Architektur, die selbst- überwachtes Lernen verwendet, um automatisch strukturelle Darstellungen von Dateien in Form von vektoriellen Einbettungen auf drei verschiedenen Ebenen zu lernen: auf Zellebene, auf Zeilenebene und auf Dateiebene. Wir experimentieren mit der Anwendung von strukturellen Einbettungen für verschiedene Aufgaben, nämlich Dialekterkennung, Zeilenklassifizierung und der Schätzung des Aufwands für die Datenaufbereitung. Unsere experimentellen Ergebnisse zeigen, dass strukturelle Metadaten, die entweder explizit mit Hilfe von Parsing-Grammatiken identifiziert, implizit als Dateiähnlichkeit abgeleitet oder mit Machine-Learning Architekturen erlernt werden, von grundlegender Bedeutung für die Automatisierung verschiedener Aufgaben, die Skalierung der Aufbereitung auf große Mengen von Dateien und die Bereitstellung wiederholbarer Aufbereitungspipelines sind. KW - data preparation KW - file structure KW - Datenaufbereitung KW - tabellarische Dateien KW - Dateistruktur KW - tabular data Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624351 ER - TY - JOUR A1 - Despujol Zabala, Ignacio A1 - Alario Hoyos, Carlos A1 - Turró Ribalta, Carlos A1 - Delgado Kloos, Carlos A1 - Montoro Manrique, Germán A1 - Busquets Mataix, Jaime T1 - Transforming Open Edx into the next On-Campus LMS BT - an ongoing project N2 - Open edX is an incredible platform to deliver MOOCs and SPOCs, designed to be robust and support hundreds of thousands of students at the same time. Nevertheless, it lacks a lot of the fine-grained functionality needed to handle students individually in an on-campus course. This short session will present the ongoing project undertaken by the 6 public universities of the Region of Madrid plus the Universitat Politècnica de València, in the framework of a national initiative called UniDigital, funded by the Ministry of Universities of Spain within the Plan de Recuperación, Transformación y Resiliencia of the European Union. This project, led by three of these Spanish universities (UC3M, UPV, UAM), is investing more than half a million euros with the purpose of bringing the Open edX platform closer to the functionalities required for an LMS to support on-campus teaching. The aim of the project is to coordinate what is going to be developed with the Open edX development community, so these developments are incorporated into the core of the Open edX platform in its next releases. Features like a complete redesign of platform analytics to make them real-time, the creation of dashboards based on these analytics, the integration of a system for customized automatic feedback, improvement of exams and tasks and the extension of grading capabilities, improvements in the graphical interfaces for both students and teachers, the extension of the emailing capabilities, redesign of the file management system, integration of H5P content, the integration of a tool to create mind maps, the creation of a system to detect students at risk, or the integration of an advanced voice assistant and a gamification mobile app, among others, are part of the functionalities to be developed. The idea is to transform a first-class MOOC platform into the next on-campus LMS. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-625122 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Dietz, Michael A1 - Roth, Dennis ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Student-centered re-design of an online course with card sorting BT - how to quickly get a mental model of students JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - “How can a course structure be redesigned based on empirical data to enhance the learning effectiveness through a student-centered approach using objective criteria?”, was the research question we asked. “Digital Twins for Virtual Commissioning of Production Machines” is a course using several innovative concepts including an in-depth practical part with online experiments, called virtual labs. The teaching-learning concept is continuously evaluated. Card Sorting is a popular method for designing information architectures (IA), “a practice of effectively organizing, structuring, and labeling the content of a website or application into a structuref that enables efficient navigation” [11]. In the presented higher education context, a so-called hybrid card sort was used, in which each participants had to sort 70 cards into seven predefined categories or create new categories themselves. Twelve out of 28 students voluntarily participated in the process and short interviews were conducted after the activity. The analysis of the category mapping creates a quantitative measure of the (dis-)similarity of the keywords in specific categories using hierarchical clustering (HCA). The learning designer could then interpret the results to make decisions about the number, labeling and order of sections in the course. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624843 SP - 339 EP - 350 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Thomas, Max A1 - Staubitz, Thomas A1 - Meinel, Christoph ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Preparing MOOChub metadata for the future of online learning BT - optimizing for AI recommendation services JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - With the growing number of online learning resources, it becomes increasingly difficult and overwhelming to keep track of the latest developments and to find orientation in the plethora of offers. AI-driven services to recommend standalone learning resources or even complete learning paths are discussed as a possible solution for this challenge. To function properly, such services require a well-defined set of metadata provided by the learning resource. During the last few years, the so-called MOOChub metadata format has been established as a de-facto standard by a group of MOOC providers in German-speaking countries. This format, which is based on schema.org, already delivers a quite comprehensive set of metadata. So far, this set has been sufficient to list, display, sort, filter, and search for courses on several MOOC and open educational resources (OER) aggregators. AI recommendation services and further automated integration, beyond a plain listing, have special requirements, however. To optimize the format for proper support of such systems, several extensions and modifications have to be applied. We herein report on a set of suggested changes to prepare the format for this task. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624830 SP - 329 EP - 338 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Shlaka, Souhad A1 - Ouahib, Sara A1 - Berrada, Khalid ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - A retrospective feedback of MOOCS in Morocco BT - what is the best scenario for the Moroccan higher education? JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The integration of MOOCs into the Moroccan Higher Education (MHE) took place in 2013 by developing different partnerships and projects at national and international levels. As elsewhere, the Covid-19 crisis has played an important role in accelerating distance education in MHE. However, based on our experience as both university professors and specialists in educational engineering, the effective execution of the digital transition has not yet been implemented. Thus, in this article, we present a retrospective feedback of MOOCs in Morocco, focusing on the policies taken by the government to better support the digital transition in general and MOOCs in particular. We are therefore seeking to establish an optimal scenario for the promotion of MOOCs, which emphasizes the policies to be considered, and which recalls the importance of conducting a delicate articulation taking into account four levels, namely environmental, institutional, organizational and individual. We conclude with recommendations that are inspired by the Moroccan academic contex that focus on the major role that MOOCs plays for university students and on maintaining lifelong learning. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624826 SP - 317 EP - 327 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Wasilewski, Julie A1 - Khaneboubi, Mehdi A1 - Bruillard, Éric ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - How to detect At-Risk learners in professional finance MOOCs BT - step one JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - “Financial Analysis” is an online course designed for professionals consisting of three MOOCs, offering a professionally and institutionally recognized certificate in finance. The course is open but not free of charge and attracts mostly professionals from the banking industry. The primary objective of this study is to identify indicators that can predict learners at high risk of failure. To achieve this, we analyzed data from a previous course that had 875 enrolled learners and involve in the course during Fall 2021. We utilized correspondence analysis to examine demographic and behavioral variables. The initial results indicate that demographic factors have a minor impact on the risk of failure in comparison to learners’ behaviors on the course platform. Two primary profiles were identified: (1) successful learners who utilized all the documents offered and spent between one to two hours per week, and (2) unsuccessful learners who used less than half of the proposed documents and spent less than one hour per week. Between these groups, at-risk students were identified as those who used more than half of the proposed documents and spent more than two hours per week. The goal is to identify those in group 1 who may be at risk of failing and those in group 2 who may succeed in the current MOOC, and to implement strategies to assist all learners in achieving success. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624818 SP - 305 EP - 316 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Kennedy, Eileen A1 - Laurillard, Diana A1 - Zeitoun, Samar ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - The Comooc model for global professional collaboration on sustainability JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - This paper presents a new design for MOOCs for professional development of skills needed to meet the UN Sustainable Development Goals – the CoMOOC or Co-designed Massive Open Online Collaboration. The CoMOOC model is based on co-design with multiple stakeholders including end-users within the professional communities the CoMOOC aims to reach. This paper shows how the CoMOOC model could help the tertiary sector deliver on the UN Sustainable Development Goals (UNSDGs) – including but not limited to SDG 4 Education – by providing a more effective vehicle for professional development at a scale that the UNSDGs require. Interviews with professionals using MOOCs, and design-based research with professionals have informed the development of the Co-MOOC model. This research shows that open, online, collaborative learning experiences are highly effective for building professional community knowledge. Moreover, this research shows that the collaborative learning design at the heart of the CoMOOC model is feasible cross-platform Research with teachers working in crisis contexts in Lebanon, many of whom were refugees, will be presented to show how this form of large scale, co-designed, online learning can support professionals, even in the most challenging contexts, such as mass displacement, where expertise is urgently required. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624803 SP - 291 EP - 303 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Utunen, Heini A1 - Attias, Melissa ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - xMOOCs BT - modality for mass reach during the pandemic for the World Health Organization JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The World Health Organization designed OpenWHO.org to provide an inclusive and accessible online environment to equip learners across the globe with critical up-to-date information and to be able to effectively protect themselves in health emergencies. The platform thus focuses on the eXtended Massive Open Online Course (xMOOC) modality – contentfocused and expert-driven, one-to-many modelled, and self-paced for scalable learning. In this paper, we describe how OpenWHO utilized xMOOCs to reach mass audiences during the COVID-19 pandemic; the paper specifically examines the accessibility, language inclusivity and adaptability of hosted xMOOCs. As of February 2023, OpenWHO had 7.5 million enrolments across 200 xMOOCs on health emergency, epidemic, pandemic and other public health topics available across 65 languages, including 46 courses targeted for the COVID-19 pandemic. Our results suggest that the xMOOC modality allowed OpenWHO to expand learning during the pandemic to previously underrepresented groups, including women, participants ages 70 and older, and learners younger than age 20. The OpenWHO use case shows that xMOOCs should be considered when there is a need for massive knowledge transfer in health emergency situations, yet the approach should be context-specific according to the type of health emergency, targeted population and region. Our evidence also supports previous calls to put intervention elements that contribute to removing barriers to access at the core of learning and health information dissemination. Equity must be the fundamental principle and organizing criteria for public health work. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624788 SP - 279 EP - 289 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Moura Santos, Ana A1 - Corti, Paola A1 - Felipe Coimbra Costa, Luis ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - How to reuse inclusive stem Moocs in blended settings to engage young girls to scientific careers JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The FOSTWOM project (2019–2022), an ERASMUS+ funding, gave METID (Politecnico di Milano) and the MOOC Técnico (Instituto Superior Técnico, University of Lisbon), together with other partners, the opportunity to support the design and creation of gender-inclusive MOOCs. Among other project outputs, we designed a toolkit and a framework that enabled the production of two MOOCs for undergraduate and graduate students in Science, Technology, Engineering and Maths (STEM) and used them as academic content free of gender stereotypes about intellectual ability. In this short paper, the authors aim to 1) briefly share the main outputs of the project; 2) tell the story of how the FOSTWOM approach together with 3) a motivational strategy, the Heroine’s Learning Journey, proved to be effective in the context of rural and marginal areas in Brazil, with young girls as a specific target audience. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624756 SP - 271 EP - 278 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Lorenz, Anja A1 - Bock, Stefanie A1 - Schulte-Ostermann, Juleka ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Challenges and proposals for introducing digital certificates in higher education infrastructures JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Questions about the recognition of MOOCs within and outside higher education were already being raised in the early 2010s. Today, recognition decisions are still made more or less on a case-by-case basis. However, digital certification approaches are now emerging that could automate recognition processes. The technical development of the required machinereadable documents and infrastructures is already well advanced in some cases. The DigiCerts consortium has developed a solution based on a collective blockchain. There are ongoing and open discussions regarding the particular technology, but the institutional implementation of digital certificates raises further questions. A number of workshops have been held at the Institute for Interactive Systems at Technische Hochschule Lübeck, which have identified the need for new responsibilities for issuing certificates. It has also become clear that all members of higher education institutions need to develop skills in the use of digital certificates. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624701 SP - 263 EP - 270 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Neuböck, Kristina A1 - Linschinger, Nadine ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Central elements of knowledge and competence development with MOOCs BT - using the example of the OER-MOOC JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - To implement OERs at HEIs sustainably, not just technical infrastructure is required, but also well-trained staff. The University of Graz is in charge of an OER training program for university staff as part of the collaborative project Open Education Austria Advanced (OEAA) with the aim of ensuring long-term competence growth in the use and creation of OERs. The program consists of a MOOC and a guided blended learning format that was evaluated to find out which accompanying teaching and learning concepts can best facilitate targeted competence development. The evaluation of the program shows that learning videos, self-study assignments and synchronous sessions are most useful for the learning process. The results indicate that the creation of OERs is a complex process that can be undergone more effectively in the guided program. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624668 SP - 255 EP - 262 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Concia, Francesca A1 - Distler, Petr A1 - Law, Gareth A1 - Macerata, Elena A1 - Mariani, Mario A1 - Mossini, Eros A1 - Negrin, Maddalena A1 - Štrok, Marko ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - An experience in developing models to use MOOCs in teaching and to advocate OERs JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Loss of expertise in the fields of Nuclear- and Radio-Chemistry (NRC) is problematic at a scientific and social level. This has been addressed by developing a MOOC, in order to let students in scientific matters discover all the benefits of NRC to society and improving their awareness of this discipline. The MOOC “Essential Radiochemistry for Society” includes current societal challenges related to health, clean and sustainable energy for safety and quality of food and agriculture. NRC teachers belonging to CINCH network were invited to use the MOOC in their teaching, according to various usage models: on the basis of these different experiences, some usage patterns were designed, describing context characteristics (number and age of students, course), activities’ scheduling and organization, results and students’ feedback, with the aim of encouraging the use of MOOCs in university teaching, as an opportunity for both lecturers and students. These models were the basis of a “toolkit for teachers”. By experiencing digital teaching resources created by different lecturers, CINCH teachers took a first meaningful step towards understanding the worth of Open Educational Resources (OER) and the importance of their creation, adoption and sharing for knowledge progress. In this paper, the entire path from MOOC concept to MOOC different usage models, to awareness-raising regarding OER is traced in conceptual stages. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624609 SP - 239 EP - 254 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Alario Hoyos, Carlos A1 - Delgado Kloos, Carlos A1 - Kiendl, Doris A1 - Terzieva, Liliya ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Innovat MOOC BT - teacher training on educational innovation in higher education JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The COVID-19 pandemic has revealed the importance for university teachers to have adequate pedagogical and technological competences to cope with the various possible educational scenarios (face-to-face, online, hybrid, etc.), making use of appropriate active learning methodologies and supporting technologies to foster a more effective learning environment. In this context, the InnovaT project has been an important initiative to support the development of pedagogical and technological competences of university teachers in Latin America through several trainings aiming to promote teacher innovation. These trainings combined synchronous online training through webinars and workshops with asynchronous online training through the MOOC “Innovative Teaching in Higher Education.” This MOOC was released twice. The first run took place right during the lockdown of 2020, when Latin American teachers needed urgent training to move to emergency remote teaching overnight. The second run took place in 2022 with the return to face-to-face teaching and the implementation of hybrid educational models. This article shares the results of the design of the MOOC considering the constraints derived from the lockdowns applied in each country, the lessons learned from the delivery of such a MOOC to Latin American university teachers, and the results of the two runs of the MOOC. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624560 SP - 229 EP - 237 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Khlaisang, Jintavee A1 - Duangchinda, Vorasuang A1 - Thammetar, Thapanee A1 - Theeraroungchaisri, Anuchai ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Instructional design for work-based skill MOOCs BT - challenges for workforce development in Thailand JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - As Thailand moves towards becoming an innovation-driven economy, the need for human capital development has become crucial. Work-based skill MOOCs, offered on Thai MOOC, a national digital learning platform launched by Thailand Cyber University Project, ministry of Higher Education, Science, Research and Innovation, provide an effective way to overcome this challenge. This paper discusses the challenges faced in designing an instruction for work-based skill MOOCs that can serve as a foundation model for many more to come. The instructional design of work-based skill courses in Thai MOOC involves four simple steps, including course selection, learning from accredited providers, course requirements completion, and certification of acquired skills. The development of such courses is ongoing at the higher education level, vocational level, and pre-university level, which serve as a foundation model for many more work-based skill MOOC that will be offered on Thai MOOC soon. The instructional design of work-based skills courses should focus on the development of currently demanded professional competencies and skills, increasing the efficiency of work in the organization, creativity, and happiness in life that meets the human resources needs of industries in the 4.0 economy era in Thailand. This paper aims to present the challenges of designing instruction for work-based skill MOOCs and suggests effective ways to design instruction to enhance workforce development in Thailand. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624318 SP - 221 EP - 227 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Ulrich, Jens-Uwe A1 - Lutfi, Ahmad A1 - Rutzen, Kilian A1 - Renard, Bernhard Y. T1 - ReadBouncer BT - precise and scalable adaptive sampling for nanopore sequencing JF - Bioinformatics N2 - Motivation: Nanopore sequencers allow targeted sequencing of interesting nucleotide sequences by rejecting other sequences from individual pores. This feature facilitates the enrichment of low-abundant sequences by depleting overrepresented ones in-silico. Existing tools for adaptive sampling either apply signal alignment, which cannot handle human-sized reference sequences, or apply read mapping in sequence space relying on fast graphical processing units (GPU) base callers for real-time read rejection. Using nanopore long-read mapping tools is also not optimal when mapping shorter reads as usually analyzed in adaptive sampling applications. Results: Here, we present a new approach for nanopore adaptive sampling that combines fast CPU and GPU base calling with read classification based on Interleaved Bloom Filters. ReadBouncer improves the potential enrichment of low abundance sequences by its high read classification sensitivity and specificity, outperforming existing tools in the field. It robustly removes even reads belonging to large reference sequences while running on commodity hardware without GPUs, making adaptive sampling accessible for in-field researchers. Readbouncer also provides a user-friendly interface and installer files for end-users without a bioinformatics background. Y1 - 2022 U6 - https://doi.org/10.1093/bioinformatics/btac223 SN - 1367-4803 SN - 1460-2059 VL - 38 IS - SUPPL 1 SP - 153 EP - 160 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Nohr, Magnus A1 - Haugsbakken, Halvdan ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - A taxonomy of video genres as a scaffolding strategy for video making in education JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - This research paper aims to introduce a novel practitioner-oriented and research-based taxonomy of video genres. This taxonomy can serve as a scaffolding strategy to support educators throughout the entire educational system in creating videos for pedagogical purposes. A taxonomy of video genres is essential as videos are highly valued resources among learners. Although the use of videos in education has been extensively researched and well-documented in systematic research reviews, gaps remain in the literature. Predominantly, researchers employ sophisticated quantitative methods and similar approaches to measure the performance of videos. This trend has led to the emergence of a strong learning analytics research tradition with its embedded literature. This body of research includes analysis of performance of videos in online courses such as Massive Open Online Courses (MOOCs). Surprisingly, this same literature is limited in terms of research outlining approaches to designing and creating educational videos, which applies to both video-based learning and online courses. This issue results in a knowledge gap, highlighting the need for developing pedagogical tools and strategies for video making. These can be found in frameworks, guidelines, and taxonomies, which can serve as scaffolding strategies. In contrast, there appears to be very few frameworks available for designing and creating videos for pedagogica purposes, apart from a few well-known frameworks. In this regard, this research paper proposes a novel taxonomy of video genres that educators can utilize when creating videos intended for use in either video-based learning environments or online courses. To create this taxonomy, a large number of videos from online courses were collected and analyzed using a mixed-method research design approach. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624294 SP - 201 EP - 220 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Thirouard, Maria A1 - de la Villèsbrunne, Marie A1 - Bernaert, Oliver ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - From MOOC to “2M-POC” BT - an approach to transform a traditional MOOC to an efficient multi-modal learning path for companies JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - IFP School develops and produces MOOCs since 2014. After the COVID-19 crisis, the demand of our industrial and international partners to offer continuous training to their employees increased drastically in an energy transition and sustainable mobility environment that finds itself in constant and rapid evolution. Therefore, it is time for a new format of digital learning tools to efficiently and rapidly train an important number of employees. To address this new demand, in a more and more digital learning environment, we have completely changed our initial MOOC model to propose an innovative SPOC business model mixing synchronous and asynchronous modules. This paper describes the work that has been done to transform our MOOCs to a hybrid SPOC model. We changed the format itself from a standard MOOC model of several weeks to small modules of one week average more adapted to our client’s demand. We precisely engineered the exchanges between learners and the social aspect all along the SPOC duration. We propose a multimodal approach with a combination of asynchronous activities like online module, exercises, and synchronous activities like webinars with experts, and after-work sessions. Additionally, this new format increases the number of uses of the MOOC resources by our professors in our own master programs. With all these actions, we were able to reach a completion rate between 80 and 96% – total enrolled –, compared to the completion rate of 15 to 28% – total enrolled – as to be recorded in our original MOOC format. This is to be observed for small groups (50–100 learners) as SPOC but also for large groups (more than 2500 learners), as a Massive and Multimodal Private Online Course (“2M-POC”). Today a MOOC is not a simple assembly of videos, text, discussions forums and validation exercises but a complete multimodal learning path including social learning, personal followup, synchronous and asynchronous modules. We conclude that the original MOOC format is not at all suitable to propose efficient training to companies, and we must re-engineer the learning path to have a SPOC hybrid and multimodal training compatible with a cost-effective business model. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624268 SP - 187 EP - 200 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Ebner, Martin A1 - Edelsbrunner, Sarah A1 - Hohla-Sejkora, Katharina A1 - Mair, Bettina A1 - Schön, Sandra A1 - Lipp, Silvia A1 - Steinkellner, Iris A1 - Stojcevic, Ivana A1 - Zwiauer, Charlotte ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Impact assessment of a MOOC platform BT - considerations, development, and results JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - In 2020, the project “iMooX – The MOOC Platform as a Service for all Austrian Universities” was launched. It is co-financed by the Austrian Ministry of Education, Science and Research. After half of the funding period, the project management wants to assess and share results and outcomes but also address (potential) additional “impacts” of the MOOC platform. Building upon work on OER impact assessment, this contribution describes in detail how the specific iMooX.at approach of impact measurement was developed. Literature review, stakeholder analysis, and problem-based interviews were the base for developing a questionnaire addressing the defined key stakeholder “MOOC creators”. The article also presents the survey results in English for the first time but focuses more on the development, strengths, and weaknesses of the selected methods. The article is seen as a contribution to the further development of impact assessment for MOOC platforms. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624222 SP - 171 EP - 186 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Theeraroungchaisri, Anuchai A1 - Thammetar, Thapanee A1 - Duangchinda, Vorasuang A1 - Khlaisang, Jintavee ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Thai MOOC academy BT - extending the platform towards a sandbox for the National Credit Bank System in Thailand JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Thai MOOC Academy is a national digital learning platform that has been serving as a mechanism for promoting lifelong learning in Thailand since 2017. It has recently undergone significant improvements and upgrades, including the implementation of a credit bank system and a learner’s eportfolio system interconnected with the platform. Thai MOOC Academy is introducing a national credit bank system for accreditation and management, which allows for the transfer of expected learning outcomes and educational qualifications between formal education, non-formal education, and informal education. The credit bank system has five distinct features, including issuing forgery-prevented certificates, recording learning results, transferring external credits within the same wallet, accumulating learning results, and creating a QR code for verification purposes. The paper discusses the features and future potential of Thai MOOC Academy, as it is extended towards a sandbox for the national credit bank system in Thailand. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624212 SP - 163 EP - 169 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Staubitz, Thomas A1 - Serth, Sebastian A1 - Thomas, Max A1 - Ebner, Martin A1 - Koschutnig-Ebner, Markus A1 - Rampelt, Florian A1 - von Stetten, Alexander A1 - Wittke, Andreas ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - A metastandard for the international exchange of MOOCs BT - the MOOChub as first prototype JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The MOOChub is a joined web-based catalog of all relevant German and Austrian MOOC platforms that lists well over 750 Massive Open Online Courses (MOOCs). Automatically building such a catalog requires that all partners describe and publicly offer the metadata of their courses in the same way. The paper at hand presents the genesis of the idea to establish a common metadata standard and the story of its subsequent development. The result of this effort is, first, an open-licensed de-facto-standard, which is based on existing commonly used standards and second, a first prototypical platform that is using this standard: the MOOChub, which lists all courses of the involved partners. This catalog is searchable and provides a more comprehensive overview of basically all MOOCs that are offered by German and Austrian MOOC platforms. Finally, the upcoming developments to further optimize the catalog and the metadata standard are reported. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-624154 SP - 147 EP - 161 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Giannatelli, Ada A1 - Tomasini, Alessandra ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Descriptors and EU Standards to support the recognition of MOOCs JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Digital technologies have enabled a variety of learning offers that opened new challenges in terms of recognition of formal, informal and non-formal learning, such as MOOCs. This paper focuses on how providing relevant data to describe a MOOC is conducive to increase the transparency of information and, ultimately, the flexibility of European higher education. The EU-funded project ECCOE took up these challenges and developed a solution by identifying the most relevant descriptors of a learning opportunity with a view to supporting a European system for micro-credentials. Descriptors indicate the specific properties of a learning opportunity according to European standards. They can provide a recognition framework also for small volumes of learning (micro-credentials) to support the integration of non-formal learning (MOOCs) into formal learning (e.g. institutional university courses) and to tackle skills shortage, upskilling and reskilling by acquiring relevant competencies. The focus on learning outcomes can facilitate the recognition of skills and competences of students and enhance both virtual and physical mobility and employability. This paper presents two contexts where ECCOE descriptors have been adopted: the Politecnico di Milano MOOC platform (Polimi Open Knowledge – POK), which is using these descriptors as the standard information to document the features of its learning opportunities, and the EU-funded Uforest project on urban forestry, which developed a blended training program for students of partner universities whose MOOCs used the ECCOE descriptors. Practice with ECCOE descriptors shows how they can be used not only to detail MOOC features, but also as a compass to design the learning offer. In addition, some rules of thumb can be derived and applied when using specific descriptors. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-623967 SP - 133 EP - 146 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Khaneboubi, Mehdi ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Visualizing students flows to monitor persistence JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Founded in 2013, OpenClassrooms is a French online learning company that offers both paid courses and free MOOCs on a wide range of topics, including computer science and education. In 2021, in partnership with the EDA research unit, OpenClassrooms shared a database to solve the problem of how to increase persistence in their paid courses, which consist of a series of MOOCs and human mentoring. Our statistical analysis aims to identify reasons for dropouts that are due to the course design rather than demographic predictors or external factors.We aim to identify at-risk students, i.e. those who are on the verge of dropping out at a specific moment. To achieve this, we use learning analytics to characterize student behavior. We conducted data analysis on a sample of data related to the “Web Designers” and “Instructional Design” courses. By visualizing the student flow and constructing speed and acceleration predictors, we can identify which parts of the course need to be calibrated and when particular attention should be paid to these at-risk students. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-623906 SP - 121 EP - 131 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Dixon, Fred A1 - Trabucchi, Stefania ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Using analytics in a large virtual classroom for Open edX JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The main aim of this article is to explore how learning analytics and synchronous collaboration could improve course completion and learner outcomes in MOOCs, which traditionally have been delivered asynchronously. Based on our experience with developing BigBlueButton, a virtual classroom platform that provides educators with live analytics, this paper explores three scenarios with business focused MOOCs to improve outcomes and strengthen learned skills. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-623895 SP - 113 EP - 120 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Egloffstein, Marc A1 - Hünemohr, Holger A1 - Ifenthaler, Dirk ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Modularization of open online courses on the eGov-Campus BT - prospects and challenges JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Modularization describes the transformation of MOOCs from a comprehensive academic course format into smaller, more manageable learning offerings. It can be seen as one of the prerequisites for the successful implementation of MOOC-based micro-credentials in professional education and training. This short paper reports on the development and application of a modularization framework for Open Online Courses. Using the example of eGov-Campus, a German MOOC provider for the public sector linked to both academia and formal professional development, the structural specifications for modularized MOOC offerings and a methodology for course transformation as well as associated challenges in technology, organization and educational design are outlined. Following on from this, future prospects are discussed under the headings of individualization, certification and integration. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-623888 SP - 105 EP - 112 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Morales-Chan, Miguel A1 - Amado-Salvatierra, Héctor R. A1 - Hernández-Rizzardini, Rocael ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Optimizing the design, pedagogical decision-making and development of MOOCs through the use of Ai-Based tools JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - This work explores the use of different generative AI tools in the design of MOOC courses. Authors in this experience employed a variety of AI-based tools, including natural language processing tools (e.g. Chat-GPT), and multimedia content authoring tools (e.g. DALLE-2, Midjourney, Tome.ai) to assist in the course design process. The aim was to address the unique challenges of MOOC course design, which includes to create engaging and effective content, to design interactive learning activities, and to assess student learning outcomes. The authors identified positive results with the incorporation of AI-based tools, which significantly improved the quality and effectiveness of MOOC course design. The tools proved particularly effective in analyzing and categorizing course content, identifying key learning objectives, and designing interactive learning activities that engaged students and facilitated learning. Moreover, the use of AI-based tools, streamlined the course design process, significantly reducing the time required to design and prepare the courses. In conclusion, the integration of generative AI tools into the MOOC course design process holds great potential for improving the quality and efficiency of these courses. Researchers and course designers should consider the advantages of incorporating generative AI tools into their design process to enhance their course offerings and facilitate student learning outcomes while also reducing the time and effort required for course development. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-623870 SP - 95 EP - 103 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Xiaoxiao, Wang A1 - Shuangshuang, Guo ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Promoting global higher education cooperation BT - taking global MOOC and online education alliance as an example JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The massive growth of MOOCs in 2011 laid the groundwork for the achievement of SDG 4. With the various benefits of MOOCs, there is also anticipation that online education should focus on more interactivity and global collaboration. In this context, the Global MOOC and Online Education Alliance (GMA) established a diverse group of 17 world-leading universities and three online education platforms from across 14 countries on all six continents in 2020. Through nearly three years of exploration, GMA has gained experience and achieved progress in fostering global cooperation in higher education. First, in joint teaching, GMA has promoted in-depth cooperation between members inside and outside the alliance. Examples include promoting the exchange of high-quality MOOCs, encouraging the creation of Global Hybrid Classroom, and launching Global Hybrid Classroom Certificate Programs. Second, in capacity building and knowledge sharing, GMA has launched Online Education Dialogues and the Global MOOC and Online Education Conference, inviting global experts to share best practices and attracting more than 10 million viewers around the world. Moreover, GMA is collaborating with international organizations to support teachers’ professional growth, create an online learning community, and serve as a resource for further development. Third, in public advocacy, GMA has launched the SDG Hackathon and Global Massive Open Online Challenge (GMOOC) and attracted global learners to acquire knowledge and incubate their innovative ideas within a cross-cultural community to solve real-world problems that all humans face and jointly create a better future. Based on past experiences and challenges, GMA will explore more diverse cooperation models with more partners utilizing advanced technology, provide more support for digital transformation in higher education, and further promote global cooperation towards building a human community with a shared future. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-623865 SP - 85 EP - 93 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Ebner, Martin A1 - Edelsbrunner, Sarah A1 - Hohla-Sejkora, Katharina A1 - Lipp, Silvia A1 - Schön, Sandra ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Role of MOOCs and Imoox for Austrian Universities BT - analysis of performance agreements and activities at imoox JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - This research paper provides an overview of the current state of MOOCs (massive open online courses) and universities in Austria, focusing on the national MOOC platform iMooX.at. The study begins by presenting the results of an analysis of the performance agreements of 22 Austrian public universities for the period 2022–2024, with a specific focus on the mention of MOOC activities and iMooX. The authors find that 12 of 22 (55 %) Austrian public universities use at least one of these terms, indicating a growing interest in MOOCs and online learning. Additionally, the authors analyze internal documentation data to share insights into how many universities in Austria have produced and/or used a MOOC on the iMooX platform since its launch in 2014. These findings provide a valuable measure of the current usage and monitoring of MOOCs and iMooX among Austrian higher education institutions. Overall, this research contributes to a better understanding of the current state of MOOCs and their integration within Austrian higher education. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-622134 SP - 77 EP - 84 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Richly, Keven A1 - Schlosser, Rainer A1 - Boissier, Martin T1 - Budget-conscious fine-grained configuration optimization for spatio-temporal applications JF - Proceedings of the VLDB Endowment N2 - Based on the performance requirements of modern spatio-temporal data mining applications, in-memory database systems are often used to store and process the data. To efficiently utilize the scarce DRAM capacities, modern database systems support various tuning possibilities to reduce the memory footprint (e.g., data compression) or increase performance (e.g., additional indexes). However, the selection of cost and performance balancing configurations is challenging due to the vast number of possible setups consisting of mutually dependent individual decisions. In this paper, we introduce a novel approach to jointly optimize the compression, sorting, indexing, and tiering configuration for spatio-temporal workloads. Further, we consider horizontal data partitioning, which enables the independent application of different tuning options on a fine-grained level. We propose different linear programming (LP) models addressing cost dependencies at different levels of accuracy to compute optimized tuning configurations for a given workload and memory budgets. To yield maintainable and robust configurations, we extend our LP-based approach to incorporate reconfiguration costs as well as a worst-case optimization for potential workload scenarios. Further, we demonstrate on a real-world dataset that our models allow to significantly reduce the memory footprint with equal performance or increase the performance with equal memory size compared to existing tuning heuristics. KW - General Earth and Planetary Sciences KW - Water Science and Technology KW - Geography, Planning and Development Y1 - 2022 U6 - https://doi.org/10.14778/3565838.3565858 SN - 2150-8097 VL - 15 IS - 13 SP - 4079 EP - 4092 PB - Association for Computing Machinery (ACM) CY - [New York] ER - TY - JOUR A1 - Haugsbakken, Halvdan A1 - Hagelia, Marianne ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - An asynchronous cooperative leaning design in a Small Private Online Course (SPOC) JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - This short paper sets out to propose a novel and interesting learning design that facilitates for cooperative learning in which students do not conduct traditional group work in an asynchronous online education setting. This learning design will be explored in a Small Private Online Course (SPOC) among teachers and school managers at a teacher education. Such an approach can be made possible by applying specific criteria commonly used to define collaborative learning. Collaboration can be defined, among other things, as a structured way of working among students that includes elements of co-laboring. The cooperative learning design involves adapting various traditional collaborative learning approaches for use in an online learning environment. A critical component of this learning design is that students work on a self-defined case project related to their professional practices. Through an iterative process, students will receive ongoing feedback and formative assessments from instructors and follow students at specific points, meaning that co-constructing of knowledge and learning takes place as the SPOC progresses. This learning design can contribute to better learning experiences and outcomes for students, and be a valuable contribution to current research discussions on learning design in Massive Open Online Courses (MOOCs). KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-622107 SP - 67 EP - 76 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Doğu Özdemir, Paker A1 - Can Bayer, Burak A1 - Mercan, Duygu A1 - Buyurucu, Gamze ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - MOOC-based Personalized Learning Experience (Ple) BT - an innovative approach to elective courses JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - This qualitative study explores the impact of Personalized Learning Experience (PLE) courses at a higher education institution from the perspective of undergraduate students. The PLE program requires students to take at least one of their elective courses in the form of MOOCs during their undergraduate studies. Drawing on interviews with six students across different faculties, the study identified four key themes that encapsulate the effects of PLE courses: (1) Certificate driven learning with a focus on occupation skill enhancement, (2) diverse course offerings to enhance personal and academic development, (3) learning flexibility, and (4) student satisfaction. The findings suggest that PLE courses offered through MOOC platforms allow students to broaden their academic horizons, gain valuable skills, and tailor their education to better align with their interests and goals. Furthermore, this study highlights the potential benefits of incorporating PLE courses in higher education institutions, emphasizing their role in promoting a more dynamic and student-centered learning environment. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-622098 SP - 59 EP - 66 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Steinbeck, Hendrik A1 - Meinel, Christoph ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - What makes an educational video? BT - deconstructing characteristics of video production styles for MOOCs JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - In an effort to describe and produce different formats for video instruction, the research community in technology-enhanced learning, and MOOC scholars in particular, have focused on the general style of video production: whether it is a digitally scripted “talk-and-chalk” or a “talking head” version of a learning unit. Since these production styles include various sub-elements, this paper deconstructs the inherited elements of video production in the context of educational live-streams. Using over 700 videos – both from synchronous and asynchronous modalities of large video-based platforms (YouTube and Twitch), 92 features were found in eight categories of video production. These include commonly analyzed features such as the use of green screen and a visible instructor, but also less studied features such as social media connections and changing camera perspective depending on the topic being covered. Overall, the research results enable an analysis of common video production styles and a toolbox for categorizing new formats – independent of their final (a)synchronous use in MOOCs. Keywords: video production, MOOC video styles, live-streaming. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-622086 SP - 47 EP - 58 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Xue, Wei A1 - Bruillard, Éric ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - MOOC in private Chinese universities BT - behavior and attitude of students learning foreign languages JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - This paper investigates private university students’ language learning activities in MOOC platforms and their attitude toward it. The study explores the development of MOOC use in Chinese private universities, with a focus on two modes: online et blended. We conducted empirical studies with students learning French and Japanese as a second foreign language, using questionnaires (N = 387) and interviews (N = 20) at a private university in Wuhan. Our results revealed that the majority of students used the MOOC platform more than twice a week and focused on the MOOC video, materials and assignments. However, we also found that students showed less interest in online communication (forums). Those who worked in the blended learning mode, especially Japanese learning students, had a more positive attitude toward MOOCs than other students. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-621811 SP - 37 EP - 45 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Trilla, Irene A1 - Drimalla, Hanna A1 - Bajbouj, Malek A1 - Dziobek, Isabel T1 - The influence of reward on facial mimicry BT - no evidence for a significant effect of oxytocin JF - Frontiers in behavioral neuroscience N2 - Recent findings suggest a role of oxytocin on the tendency to spontaneously mimic the emotional facial expressions of others. Oxytocin-related increases of facial mimicry, however, seem to be dependent on contextual factors. Given previous literature showing that people preferentially mimic emotional expressions of individuals associated with high (vs. low) rewards, we examined whether the reward value of the mimicked agent is one factor influencing the oxytocin effects on facial mimicry. To test this hypothesis, 60 male adults received 24 IU of either intranasal oxytocin or placebo in a double-blind, between-subject experiment. Next, the value of male neutral faces was manipulated using an associative learning task with monetary rewards. After the reward associations were learned, participants watched videos of the same faces displaying happy and angry expressions. Facial reactions to the emotional expressions were measured with electromyography. We found that participants judged as more pleasant the face identities associated with high reward values than with low reward values. However, happy expressions by low rewarding faces were more spontaneously mimicked than high rewarding faces. Contrary to our expectations, we did not find a significant direct effect of intranasal oxytocin on facial mimicry, nor on the reward-driven modulation of mimicry. Our results support the notion that mimicry is a complex process that depends on contextual factors, but failed to provide conclusive evidence of a role of oxytocin on the modulation of facial mimicry. KW - oxytocin KW - facial mimicry KW - reward KW - EMG KW - social modulation KW - null results Y1 - 2020 U6 - https://doi.org/10.3389/fnbeh.2020.00088 SN - 1662-5153 VL - 14 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Limanowski, Jakub A1 - Lopes, Pedro A1 - Keck, Janis A1 - Baudisch, Patrick A1 - Friston, Karl A1 - Blankenburg, Felix T1 - Action-dependent processing of touch in the human parietal operculum and posterior insula JF - Cerebral Cortex N2 - Somatosensory input generated by one's actions (i.e., self-initiated body movements) is generally attenuated. Conversely, externally caused somatosensory input is enhanced, for example, during active touch and the haptic exploration of objects. Here, we used functional magnetic resonance imaging (fMRI) to ask how the brain accomplishes this delicate weighting of self-generated versus externally caused somatosensory components. Finger movements were either self-generated by our participants or induced by functional electrical stimulation (FES) of the same muscles. During half of the trials, electrotactile impulses were administered when the (actively or passively) moving finger reached a predefined flexion threshold. fMRI revealed an interaction effect in the contralateral posterior insular cortex (pIC), which responded more strongly to touch during self-generated than during FES-induced movements. A network analysis via dynamic causal modeling revealed that connectivity from the secondary somatosensory cortex via the pIC to the supplementary motor area was generally attenuated during self-generated relative to FES-induced movements-yet specifically enhanced by touch received during self-generated, but not FES-induced movements. Together, these results suggest a crucial role of the parietal operculum and the posterior insula in differentiating self-generated from externally caused somatosensory information received from one's moving limb. KW - active touch KW - dynamic causal modeling KW - insula KW - parietal operculum KW - somatosensation Y1 - 2019 U6 - https://doi.org/10.1093/cercor/bhz111 SN - 1047-3211 SN - 1460-2199 VL - 30 IS - 2 SP - 607 EP - 617 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Jin, Tonje ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Scott, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - “One video fit for all” BT - game inspired online TEACHING in mathematics in STEM education JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Online learning in mathematics has always been challenging, especially for mathematics in STEM education. This paper presents how to make “one fit for all” lecture videos for mathematics in STEM education. In general, we do believe that there is no such thing as “one fit for all” video. The curriculum requires a high level of prior knowledge in mathematics from high school to get a good understanding, and the variation of prior knowledge levels among STEM education students is often high. This creates challenges for both online teaching and on-campus teaching. This article presents experimenting and researching on a video format where students can get a real-time feeling, and which fits their needs regarding their existing prior knowledge. They have the possibility to ask and receive answers during the video without having to feel that they must jump into different sources, which helps to reduce unnecessary distractions. The fundamental video format presented here is that of dynamic branching videos, which has to little degree been researched in education related studies. The reason might be that this field is quite new for higher education, and there is relatively high requirement on the video editing skills from the teachers’ side considering the platforms that are available so far. The videos are implemented for engineering students who take the Linear Algebra course at the Norwegian University of Science and Technology in spring 2023. Feedback from the students gathered via anonymous surveys so far (N = 21) is very positive. With the high suitability for online teaching, this video format might lead the trend of online learning in the future. The design and implementation of dynamic videos in mathematics in higher education was presented for the first time at the EMOOCs conference 2023. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-621080 SP - 21 EP - 35 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Shi, Feng A1 - Schirneck, Friedrich Martin A1 - Friedrich, Tobias A1 - Kötzing, Timo A1 - Neumann, Frank T1 - Reoptimization time analysis of evolutionary algorithms on linear functions under dynamic uniform constraints JF - Algorithmica : an international journal in computer science N2 - Rigorous runtime analysis is a major approach towards understanding evolutionary computing techniques, and in this area linear pseudo-Boolean objective functions play a central role. Having an additional linear constraint is then equivalent to the NP-hard Knapsack problem, certain classes thereof have been studied in recent works. In this article, we present a dynamic model of optimizing linear functions under uniform constraints. Starting from an optimal solution with respect to a given constraint bound, we investigate the runtimes that different evolutionary algorithms need to recompute an optimal solution when the constraint bound changes by a certain amount. The classical (1+1) EA and several population-based algorithms are designed for that purpose, and are shown to recompute efficiently. Furthermore, a variant of the (1+(λ,λ))GA for the dynamic optimization problem is studied, whose performance is better when the change of the constraint bound is small. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-605295 SN - 0178-4617 SN - 1432-0541 VL - 82 IS - 10 SP - 3117 EP - 3123 PB - Springer CY - New York ER - TY - JOUR A1 - Kristine Jonson Carlon, May A1 - Yokoi, Kensuke A1 - Maurice Gayed, John A1 - Suyama, Hiroshi A1 - Cross, Jeffrey ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Cross, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Preparing for Society 5.0 with MOOC Capabilities Extension BT - an industry-academia collaboration on learning analytics dashboard development JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - Academia-industry collaborations are beneficial when both sides bring strengths to the partnership and the collaboration outcome is of mutual benefit. These types of collaboration projects are seen as a low-risk learning opportunity for both parties. In this paper, government initiatives that can change the business landscape and academia-industry collaborations that can provide upskilling opportunities to fill emerging business needs are discussed. In light of Japan’s push for next-level modernization, a Japanese software company took a positive stance towards building new capabilities outside what it had been offering its customers. Consequently, an academic research group is laying out infrastructure for learning analytics research. An existing learning analytics dashboard was modularized to allow the research group to focus on natural language processing experiments while the software company explores a development framework suitable for data visualization techniques and artificial intelligence development. The results of this endeavor demonstrate that companies working with academia can creatively explore collaborations outside typical university-supported avenues. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-620809 SP - 9 EP - 20 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - van Esveld, Selma A1 - de Vries, Nardo A1 - Becchetti, Sibilla A1 - Dopper, Sofia A1 - van Valkenburg, Willem ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Cross, Jeffrey ED - Kristine Jonson Carlon, May ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - Impact of Mooc and Other Online Course Development on Campus Education JF - EMOOCs 2023 : Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - The TU Delft Extension School for Continuing Education develops and delivers MOOCs, programs and other online courses for lifelong learners and professionals worldwide focused on Science, Engineering & Design. At the beginning of 2022, we started a project to examine whether creating an online course had any impact on TU Delft campus education. Through a survey, we collected feedback from 68 TU Delft lecturers involved in developing and offering online courses and programs for lifelong learners and professionals. The lecturers reported on the impact of developing an online course on a personal and curricular level. The results showed that the developed online materials, and the acquired skills and experiences from creating online courses, were beneficial for campus education, especially during the transition to remote emergency teaching in the COVID-19 lockdown periods. In this short paper, we will describe the responses in detail and map the benefits and challenges experienced by lecturers when implementing their online course materials and newly acquired educational skills on campus. Finally, we will explore future possibilities to extend the reported, already relevant, impact of MOOCs and of other online courses on campus education. KW - Digitale Bildung KW - Kursdesign KW - MOOC KW - Micro Degree KW - Online-Lehre KW - Onlinekurs KW - Onlinekurs-Produktion KW - digital education KW - e-learning KW - micro degree KW - micro-credential KW - online course creation KW - online course design KW - online teaching Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-620785 SP - 1 EP - 8 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Piro, Vitor C. A1 - Dadi, Temesgen H. A1 - Seiler, Enrico A1 - Reinert, Knut A1 - Renard, Bernhard Y. T1 - ganon BT - precise metagenomics classification against large and up-to-date sets of reference sequences JF - Bioinformatics N2 - Motivation: The exponential growth of assembled genome sequences greatly benefits metagenomics studies. However, currently available methods struggle to manage the increasing amount of sequences and their frequent updates. Indexing the current RefSeq can take days and hundreds of GB of memory on large servers. Few methods address these issues thus far, and even though many can theoretically handle large amounts of references, time/memory requirements are prohibitive in practice. As a result, many studies that require sequence classification use often outdated and almost never truly up-to-date indices. Results: Motivated by those limitations, we created ganon, a k-mer-based read classification tool that uses Interleaved Bloom Filters in conjunction with a taxonomic clustering and a k-mer counting/filtering scheme. Ganon provides an efficient method for indexing references, keeping them updated. It requires <55 min to index the complete RefSeq of bacteria, archaea, fungi and viruses. The tool can further keep these indices up-to-date in a fraction of the time necessary to create them. Ganon makes it possible to query against very large reference sets and therefore it classifies significantly more reads and identifies more species than similar methods. When classifying a high-complexity CAMI challenge dataset against complete genomes from RefSeq, ganon shows strongly increased precision with equal or better sensitivity compared with state-of-the-art tools. With the same dataset against the complete RefSeq, ganon improved the F1-score by 65% at the genus level. It supports taxonomy- and assembly-level classification, multiple indices and hierarchical classification. Y1 - 2020 U6 - https://doi.org/https://doi.org/10.1093/bioinformatics/btaa458 SN - 1367-4811 SN - 1367-4803 VL - 36 SP - 12 EP - 20 PB - Oxford Univ. Press CY - Oxford ER - TY - THES A1 - Shekhar, Sumit T1 - Image and video processing based on intrinsic attributes N2 - Advancements in computer vision techniques driven by machine learning have facilitated robust and efficient estimation of attributes such as depth, optical flow, albedo, and shading. To encapsulate all such underlying properties associated with images and videos, we evolve the concept of intrinsic images towards intrinsic attributes. Further, rapid hardware growth in the form of high-quality smartphone cameras, readily available depth sensors, mobile GPUs, or dedicated neural processing units have made image and video processing pervasive. In this thesis, we explore the synergies between the above two advancements and propose novel image and video processing techniques and systems based on them. To begin with, we investigate intrinsic image decomposition approaches and analyze how they can be implemented on mobile devices. We propose an approach that considers not only diffuse reflection but also specular reflection; it allows us to decompose an image into specularity, albedo, and shading on a resource constrained system (e.g., smartphones or tablets) using the depth data provided by the built-in depth sensors. In addition, we explore how on-device depth data can further be used to add an immersive dimension to 2D photos, e.g., showcasing parallax effects via 3D photography. In this regard, we develop a novel system for interactive 3D photo generation and stylization on mobile devices. Further, we investigate how adaptive manipulation of baseline-albedo (i.e., chromaticity) can be used for efficient visual enhancement under low-lighting conditions. The proposed technique allows for interactive editing of enhancement settings while achieving improved quality and performance. We analyze the inherent optical flow and temporal noise as intrinsic properties of a video. We further propose two new techniques for applying the above intrinsic attributes for the purpose of consistent video filtering. To this end, we investigate how to remove temporal inconsistencies perceived as flickering artifacts. One of the techniques does not require costly optical flow estimation, while both provide interactive consistency control. Using intrinsic attributes for image and video processing enables new solutions for mobile devices – a pervasive visual computing device – and will facilitate novel applications for Augmented Reality (AR), 3D photography, and video stylization. The proposed low-light enhancement techniques can also improve the accuracy of high-level computer vision tasks (e.g., face detection) under low-light conditions. Finally, our approach for consistent video filtering can extend a wide range of image-based processing for videos. N2 - Fortschritte im Bereich der Computer-Vision-Techniken, die durch Maschinelles Lernen vorangetrieben werden, haben eine robuste und effiziente Schätzung von Attributen wie Tiefe, optischer Fluss, Albedo, und Schattierung ermöglicht. Um all diese zugrundeliegenden Eigenschaften von Bildern und Videos zu erfassen, entwickeln wir das Konzept der intrinsischen Bilder zu intrinsischen Attributen weiter. Darüber hinaus hat die rasante Entwicklung der Hardware in Form von hochwertigen Smartphone-Kameras, leicht verfügbaren Tiefensensoren, mobilen GPUs, oder speziellen neuronalen Verarbeitungseinheiten die Bild- und Videoverarbeitung allgegenwärtig gemacht. In dieser Arbeit erforschen wir die Synergien zwischen den beiden oben genannten Fortschritten und schlagen neue Bild- und Videoverarbeitungstechniken und -systeme vor, die auf ihnen basieren. Zunächst untersuchen wir intrinsische Bildzerlegungsansätze und analysieren, wie sie auf mobilen Geräten implementiert werden können. Wir schlagen einen Ansatz vor, der nicht nur die diffuse Reflexion, sondern auch die spiegelnde Reflexion berücksichtigt; er ermöglicht es uns, ein Bild auf einem ressourcenbeschränkten System (z. B. Smartphones oder Tablets) unter Verwendung der von den eingebauten Tiefensensoren bereitgestellten Tiefendaten in Spiegelung, Albedo und Schattierung zu zerlegen. Darüber hinaus erforschen wir, wie geräteinterne Tiefendaten genutzt werden können, um 2D-Fotos eine immersive Dimension hinzuzufügen, z. B. um Parallaxen-Effekte durch 3D-Fotografie darzustellen. In diesem Zusammenhang entwickeln wir ein neuartiges System zur interaktiven 3D-Fotoerstellung und -Stylisierung auf mobilen Geräten. Darüber hinaus untersuchen wir, wie eine adaptive Manipulation der Grundlinie-Albedo (d.h. der Farbintensität) für eine effiziente visuelle Verbesserung bei schlechten Lichtverhältnissen genutzt werden kann. Die vorgeschlagene Technik ermöglicht die interaktive Bearbeitung von Verbesserungseinstellungen bei verbesserter Qualität und Leistung. Wir analysieren den inhärenten optischen Fluss und die zeitliche Konsistenz als intrinsische Eigenschaften eines Videos. Darüber hinaus schlagen wir zwei neue Techniken zur Anwendung der oben genannten intrinsischen Attribute zum Zweck der konsistenten Videofilterung vor. Zu diesem Zweck untersuchen wir, wie zeitliche Inkonsistenzen, die als Flackerartefakte wahrgenommen werden, entfernt werden können. Eine der Techniken erfordert keine kostspielige optische Flussschätzung, während beide eine interaktive Konsistenzkontrolle bieten. Die Verwendung intrinsischer Attribute für die Bild- und Videoverarbeitung ermöglicht neue Lösungen für mobile Geräte - ein visuelles Computergerät, das aufgrund seiner weltweiten Verbreitung von großer Bedeutung ist - und wird neuartige Anwendungen für Augmented Reality (AR), 3D-Fotografie und Videostylisierung ermöglichen. Die vorgeschlagenen Low-Light-Enhancement-Techniken können auch die Genauigkeit von High-Level-Computer-Vision-Aufgaben (z. B. Objekt-Tracking) unter schlechten Lichtverhältnissen verbessern. Schließlich kann unser Ansatz zur konsistenten Videofilterung eine breite Palette von bildbasierten Verarbeitungen für Videos erweitern. KW - image processing KW - image-based rendering KW - non-photorealistic rendering KW - image stylization KW - computational photography KW - Bildverarbeitung KW - bildbasiertes Rendering KW - Non-photorealistic Rendering KW - Computational Photography Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-620049 ER - TY - JOUR A1 - Casel, Katrin A1 - Dreier, Jan A1 - Fernau, Henning A1 - Gobbert, Moritz A1 - Kuinke, Philipp A1 - Villaamil, Fernando Sánchez A1 - Schmid, Markus L. A1 - van Leeuwen, Erik Jan T1 - Complexity of independency and cliquy trees JF - Discrete applied mathematics N2 - An independency (cliquy) tree of an n-vertex graph G is a spanning tree of G in which the set of leaves induces an independent set (clique). We study the problems of minimizing or maximizing the number of leaves of such trees, and fully characterize their parameterized complexity. We show that all four variants of deciding if an independency/cliquy tree with at least/most l leaves exists parameterized by l are either Para-NP- or W[1]-hard. We prove that minimizing the number of leaves of a cliquy tree parameterized by the number of internal vertices is Para-NP-hard too. However, we show that minimizing the number of leaves of an independency tree parameterized by the number k of internal vertices has an O*(4(k))-time algorithm and a 2k vertex kernel. Moreover, we prove that maximizing the number of leaves of an independency/cliquy tree parameterized by the number k of internal vertices both have an O*(18(k))-time algorithm and an O(k 2(k)) vertex kernel, but no polynomial kernel unless the polynomial hierarchy collapses to the third level. Finally, we present an O(3(n) . f(n))-time algorithm to find a spanning tree where the leaf set has a property that can be decided in f (n) time and has minimum or maximum size. KW - independency tree KW - cliquy tree KW - parameterized complexity KW - Kernelization KW - algorithms KW - exact algorithms Y1 - 2018 U6 - https://doi.org/10.1016/j.dam.2018.08.011 SN - 0166-218X SN - 1872-6771 VL - 272 SP - 2 EP - 15 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Casel, Katrin A1 - Fischbeck, Philipp A1 - Friedrich, Tobias A1 - Göbel, Andreas A1 - Lagodzinski, J. A. Gregor T1 - Zeros and approximations of Holant polynomials on the complex plane JF - Computational complexity : CC N2 - We present fully polynomial time approximation schemes for a broad class of Holant problems with complex edge weights, which we call Holant polynomials. We transform these problems into partition functions of abstract combinatorial structures known as polymers in statistical physics. Our method involves establishing zero-free regions for the partition functions of polymer models and using the most significant terms of the cluster expansion to approximate them. Results of our technique include new approximation and sampling algorithms for a diverse class of Holant polynomials in the low-temperature regime (i.e. small external field) and approximation algorithms for general Holant problems with small signature weights. Additionally, we give randomised approximation and sampling algorithms with faster running times for more restrictive classes. Finally, we improve the known zero-free regions for a perfect matching polynomial. KW - Holant problems KW - approximate counting KW - partition functions KW - graph KW - polynomials Y1 - 2022 U6 - https://doi.org/10.1007/s00037-022-00226-5 SN - 1016-3328 SN - 1420-8954 VL - 31 IS - 2 PB - Springer CY - Basel ER - TY - JOUR A1 - Krestel, Ralf A1 - Chikkamath, Renukswamy A1 - Hewel, Christoph A1 - Risch, Julian T1 - A survey on deep learning for patent analysis JF - World patent information N2 - Patent document collections are an immense source of knowledge for research and innovation communities worldwide. The rapid growth of the number of patent documents poses an enormous challenge for retrieving and analyzing information from this source in an effective manner. Based on deep learning methods for natural language processing, novel approaches have been developed in the field of patent analysis. The goal of these approaches is to reduce costs by automating tasks that previously only domain experts could solve. In this article, we provide a comprehensive survey of the application of deep learning for patent analysis. We summarize the state-of-the-art techniques and describe how they are applied to various tasks in the patent domain. In a detailed discussion, we categorize 40 papers based on the dataset, the representation, and the deep learning architecture that were used, as well as the patent analysis task that was targeted. With our survey, we aim to foster future research at the intersection of patent analysis and deep learning and we conclude by listing promising paths for future work. KW - deep learning KW - patent analysis KW - text mining KW - natural language processing Y1 - 2021 U6 - https://doi.org/10.1016/j.wpi.2021.102035 SN - 0172-2190 SN - 1874-690X VL - 65 PB - Elsevier CY - Amsterdam ER - TY - BOOK A1 - Garus, Marcel A1 - Sawahn, Rohan A1 - Wanke, Jonas A1 - Tiedt, Clemens A1 - Granzow, Clara A1 - Kuffner, Tim A1 - Rosenbaum, Jannis A1 - Hagemann, Linus A1 - Wollnik, Tom A1 - Woth, Lorenz A1 - Auringer, Felix A1 - Kantusch, Tobias A1 - Roth, Felix A1 - Hanff, Konrad A1 - Schilli, Niklas A1 - Seibold, Leonard A1 - Lindner, Marc Fabian A1 - Raschack, Selina ED - Grapentin, Andreas ED - Tiedt, Clemens ED - Polze, Andreas T1 - Operating systems II - student projects N2 - This technical report presents the results of student projects which were prepared during the lecture “Operating Systems II” offered by the “Operating Systems and Middleware” group at HPI in the Summer term of 2020. The lecture covered ad- vanced aspects of operating system implementation and architecture on topics such as Virtualization, File Systems and Input/Output Systems. In addition to attending the lecture, the participating students were encouraged to gather practical experience by completing a project on a closely related topic over the course of the semester. The results of 10 selected exceptional projects are covered in this report. The students have completed hands-on projects on the topics of Operating System Design Concepts and Implementation, Hardware/Software Co-Design, Reverse Engineering, Quantum Computing, Static Source-Code Analysis, Operating Systems History, Application Binary Formats and more. It should be recognized that over the course of the semester all of these projects have achieved outstanding results which went far beyond the scope and the expec- tations of the lecture, and we would like to thank all participating students for their commitment and their effort in completing their respective projects, as well as their work on compiling this report. N2 - Dieser technische Bericht beschriebt die Ergebnisse der Projekte, welche im Rahmen der Lehrveranstaltung "Betriebssysteme II" on teilnehmenden Studierenden durchgeführt wurden. Die Lehrveranstaltung wurde von der "Betriebssysteme und Middleware" am HPI im Sommersemester 2020 durchgeführt und behandele fortgeschrittene Aspekte der Betriebssystemarchitektur und -Implementierung am Beispiel der Virtualisierung, der Dateisysteme und der Eingabe/Ausgabe (I/O) Systeme. Zusätzlich zu den Vorlesungen wurden die Studierenden angeleitet, durch die Durchführung eines begleitenden Projekts praktische Erfahrungen im Umgang mit den behandelten Themen zu sammeln. Die Ergebnisse von 10 ausgewählten, herausragenden Projekten werden in diesem Report vorgestellt. Die Studierenden haben unter anderem Projekte zu den Themen Betriebssystemdesign und -Implementierung, Hardware/Software Co-Design, Reverse Engineering, Quanten-Computing, Statische Quellcodeanalyse, Betriebssystemgeschichte, dem Binärformat von ausführbaren Dateien durchgeführt. Es ist anzuerkennen, dass alle teilnehmenden Studierenden im Verlauf des Semesters herausragende Ergebnisse erzielt haben, die weit über die Anforderungen der Lehrveranstaltung hinausgingen. Wir möchten uns bei allen teilnehmenden Studierenden für Ihren Einsatz bei der Durchführung der Projekte, sowie bei der Erstellung dieses Reports bedanken. T3 - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 142 KW - operating systems KW - network protocols KW - software/hardware co-design KW - static source-code analysis KW - reverse engineering KW - quantum computing KW - Betriebssysteme KW - Netzwerkprotokolle KW - Software/Hardware Co-Design KW - statische Quellcodeanalyse KW - Reverse Engineering KW - Quanten-Computing Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-526363 SN - 978-3-86956-524-8 SN - 1613-5652 SN - 2191-1665 IS - 142 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Hagedorn, Christopher A1 - Huegle, Johannes A1 - Schlosser, Rainer T1 - Understanding unforeseen production downtimes in manufacturing processes using log data-driven causal reasoning JF - Journal of intelligent manufacturing N2 - In discrete manufacturing, the knowledge about causal relationships makes it possible to avoid unforeseen production downtimes by identifying their root causes. Learning causal structures from real-world settings remains challenging due to high-dimensional data, a mix of discrete and continuous variables, and requirements for preprocessing log data under the causal perspective. In our work, we address these challenges proposing a process for causal reasoning based on raw machine log data from production monitoring. Within this process, we define a set of transformation rules to extract independent and identically distributed observations. Further, we incorporate a variable selection step to handle high-dimensionality and a discretization step to include continuous variables. We enrich a commonly used causal structure learning algorithm with domain-related orientation rules, which provides a basis for causal reasoning. We demonstrate the process on a real-world dataset from a globally operating precision mechanical engineering company. The dataset contains over 40 million log data entries from production monitoring of a single machine. In this context, we determine the causal structures embedded in operational processes. Further, we examine causal effects to support machine operators in avoiding unforeseen production stops, i.e., by detaining machine operators from drawing false conclusions on impacting factors of unforeseen production stops based on experience. KW - Causal structure learning KW - Log data KW - Causal inference KW - Manufacturing KW - industry Y1 - 2022 U6 - https://doi.org/10.1007/s10845-022-01952-x SN - 0956-5515 SN - 1572-8145 VL - 33 IS - 7 SP - 2027 EP - 2043 PB - Springer CY - Dordrecht ER - TY - BOOK A1 - Meinel, Christoph A1 - Galbas, Michael A1 - Hagebölling, David T1 - Digital sovereignty: insights from Germany’s education sector T1 - Digitale Souveränität: Erkenntnisse aus dem deutschen Bildungssektor N2 - Digital technology offers significant political, economic, and societal opportunities. At the same time, the notion of digital sovereignty has become a leitmotif in German discourse: the state’s capacity to assume its responsibilities and safeguard society’s – and individuals’ – ability to shape the digital transformation in a self-determined way. The education sector is exemplary for the challenge faced by Germany, and indeed Europe, of harnessing the benefits of digital technology while navigating concerns around sovereignty. It encompasses education as a core public good, a rapidly growing field of business, and growing pools of highly sensitive personal data. The report describes pathways to mitigating the tension between digitalization and sovereignty at three different levels – state, economy, and individual – through the lens of concrete technical projects in the education sector: the HPI Schul-Cloud (state sovereignty), the MERLOT data spaces (economic sovereignty), and the openHPI platform (individual sovereignty). N2 - Digitale Technologien bieten erhebliche politische, wirtschaftliche und gesellschaftliche Chancen. Zugleich ist der Begriff digitale Souveränität zu einem Leitmotiv im deutschen Diskurs über digitale Technologien geworden: das heißt, die Fähigkeit des Staates, seine Verantwortung wahrzunehmen und die Befähigung der Gesellschaft – und des Einzelnen – sicherzustellen, die digitale Transformation selbstbestimmt zu gestalten. Exemplarisch für die Herausforderung in Deutschland und Europa, die Vorteile digitaler Technologien zu nutzen und gleichzeitig Souveränitätsbedenken zu berücksichtigen, steht der Bildungssektor. Er umfasst Bildung als zentrales öffentliches Gut, ein schnell aufkommendes Geschäftsfeld und wachsende Bestände an hochsensiblen personenbezogenen Daten. Davon ausgehend beschreibt der Bericht Wege zur Entschärfung des Spannungsverhältnisses zwischen Digitalisierung und Souveränität auf drei verschiedenen Ebenen – Staat, Wirtschaft und Individuum – anhand konkreter technischer Projekte im Bildungsbereich: die HPI Schul-Cloud (staatliche Souveränität), die MERLOT-Datenräume (wirtschaftliche Souveränität) und die openHPI-Plattform (individuelle Souveränität). T3 - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 157 KW - digitalization KW - digital sovereignty KW - digital education KW - HPI Schul-Cloud KW - MERLOT KW - openHPI KW - European Union KW - Digitalisierung KW - digitale Souveränität KW - digitale Bildung KW - HPI Schul-Cloud KW - MERLOT KW - openHPI KW - Europäische Union Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-597723 SN - 978-3-86956-561-3 SN - 1613-5652 SN - 2191-1665 IS - 157 SP - 1 EP - 27 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Najafi, Pejman T1 - Leveraging data science & engineering for advanced security operations T1 - Der Einsatz von Data Science & Engineering für fortschrittliche Security Operations N2 - The Security Operations Center (SOC) represents a specialized unit responsible for managing security within enterprises. To aid in its responsibilities, the SOC relies heavily on a Security Information and Event Management (SIEM) system that functions as a centralized repository for all security-related data, providing a comprehensive view of the organization's security posture. Due to the ability to offer such insights, SIEMS are considered indispensable tools facilitating SOC functions, such as monitoring, threat detection, and incident response. Despite advancements in big data architectures and analytics, most SIEMs fall short of keeping pace. Architecturally, they function merely as log search engines, lacking the support for distributed large-scale analytics. Analytically, they rely on rule-based correlation, neglecting the adoption of more advanced data science and machine learning techniques. This thesis first proposes a blueprint for next-generation SIEM systems that emphasize distributed processing and multi-layered storage to enable data mining at a big data scale. Next, with the architectural support, it introduces two data mining approaches for advanced threat detection as part of SOC operations. First, a novel graph mining technique that formulates threat detection within the SIEM system as a large-scale graph mining and inference problem, built on the principles of guilt-by-association and exempt-by-reputation. The approach entails the construction of a Heterogeneous Information Network (HIN) that models shared characteristics and associations among entities extracted from SIEM-related events/logs. Thereon, a novel graph-based inference algorithm is used to infer a node's maliciousness score based on its associations with other entities in the HIN. Second, an innovative outlier detection technique that imitates a SOC analyst's reasoning process to find anomalies/outliers. The approach emphasizes explainability and simplicity, achieved by combining the output of simple context-aware univariate submodels that calculate an outlier score for each entry. Both approaches were tested in academic and real-world settings, demonstrating high performance when compared to other algorithms as well as practicality alongside a large enterprise's SIEM system. This thesis establishes the foundation for next-generation SIEM systems that can enhance today's SOCs and facilitate the transition from human-centric to data-driven security operations. N2 - In einem Security Operations Center (SOC) werden alle sicherheitsrelevanten Prozesse, Daten und Personen einer Organisation zusammengefasst. Das Herzstück des SOCs ist ein Security Information and Event Management (SIEM)-System, welches als zentraler Speicher aller sicherheitsrelevanten Daten fungiert und einen Überblick über die Sicherheitslage einer Organisation geben kann. SIEM-Systeme sind unverzichtbare Werkzeuge für viele SOC-Funktionen wie Monitoring, Threat Detection und Incident Response. Trotz der Fortschritte bei Big-Data-Architekturen und -Analysen können die meisten SIEMs nicht mithalten. Sie fungieren nur als Protokollsuchmaschine und unterstützen keine verteilte Data Mining und Machine Learning. In dieser Arbeit wird zunächst eine Blaupause für die nächste Generation von SIEM-Systemen vorgestellt, welche Daten verteilt, verarbeitet und in mehreren Schichten speichert, damit auch Data Mining im großen Stil zu ermöglichen. Zudem werden zwei Data Mining-Ansätze vorgeschlagen, mit denen auch anspruchsvolle Bedrohungen erkannt werden können. Der erste Ansatz ist eine neue Graph-Mining-Technik, bei der SIEM-Daten als Graph strukturiert werden und Reputationsinferenz mithilfe der Prinzipien guiltby-association (Kontaktschuld) und exempt-by-reputation (Reputationsbefreiung) implementiert wird. Der Ansatz nutzt ein heterogenes Informationsnetzwerk (HIN), welches gemeinsame Eigenschaften und Assoziationen zwischen Entitäten aus Event Logs verknüpft. Des Weiteren ermöglicht ein neuer Inferenzalgorithmus die Bestimmung der Schädlichkeit eines Kontos anhand seiner Verbindungen zu anderen Entitäten im HIN. Der zweite Ansatz ist eine innovative Methode zur Erkennung von Ausreißern, die den Entscheidungsprozess eines SOC-Analysten imitiert. Diese Methode ist besonders einfach und interpretierbar, da sie einzelne univariate Teilmodelle kombiniert, die sich jeweils auf eine kontextualisierte Eigenschaft einer Entität beziehen. Beide Ansätze wurden sowohl akademisch als auch in der Praxis getestet und haben im Vergleich mit anderen Methoden auch in großen Unternehmen eine hohe Qualität bewiesen. Diese Arbeit bildet die Grundlage für die nächste Generation von SIEM-Systemen, welche den Übergang von einer personalzentrischen zu einer datenzentrischen Perspektive auf SOCs ermöglichen. KW - cybersecurity KW - endpoint security KW - threat detection KW - intrusion detection KW - apt KW - advanced threats KW - advanced persistent threat KW - zero-day KW - security analytics KW - data-driven KW - data mining KW - data science KW - anomaly detection KW - outlier detection KW - graph mining KW - graph inference KW - machine learning KW - Advanced Persistent Threats KW - fortschrittliche Angriffe KW - Anomalieerkennung KW - APT KW - Cyber-Sicherheit KW - Data-Mining KW - Data-Science KW - datengetrieben KW - Endpunktsicherheit KW - Graphableitung KW - Graph-Mining KW - Einbruchserkennung KW - Machine-Learning KW - Ausreißererkennung KW - Sicherheitsanalyse KW - Bedrohungserkennung KW - 0-day Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-612257 ER - TY - JOUR A1 - Kruse, Sebastian A1 - Kaoudi, Zoi A1 - Contreras-Rojas, Bertty A1 - Chawla, Sanjay A1 - Naumann, Felix A1 - Quiane-Ruiz, Jorge-Arnulfo T1 - RHEEMix in the data jungle BT - a cost-based optimizer for cross-platform systems JF - The VLDB Journal N2 - Data analytics are moving beyond the limits of a single platform. In this paper, we present the cost-based optimizer of Rheem, an open-source cross-platform system that copes with these new requirements. The optimizer allocates the subtasks of data analytic tasks to the most suitable platforms. Our main contributions are: (i) a mechanism based on graph transformations to explore alternative execution strategies; (ii) a novel graph-based approach to determine efficient data movement plans among subtasks and platforms; and (iii) an efficient plan enumeration algorithm, based on a novel enumeration algebra. We extensively evaluate our optimizer under diverse real tasks. We show that our optimizer can perform tasks more than one order of magnitude faster when using multiple platforms than when using a single platform. KW - Cross-platform KW - Polystore KW - Query optimization KW - Data processing Y1 - 2020 U6 - https://doi.org/10.1007/s00778-020-00612-x SN - 1066-8888 SN - 0949-877X VL - 29 IS - 6 SP - 1287 EP - 1310 PB - Springer CY - Berlin ER - TY - THES A1 - Jain, Nitisha T1 - Representation and curation of knowledge graphs with embeddings N2 - Knowledge graphs are structured repositories of knowledge that store facts about the general world or a particular domain in terms of entities and their relationships. Owing to the heterogeneity of use cases that are served by them, there arises a need for the automated construction of domain- specific knowledge graphs from texts. While there have been many research efforts towards open information extraction for automated knowledge graph construction, these techniques do not perform well in domain-specific settings. Furthermore, regardless of whether they are constructed automatically from specific texts or based on real-world facts that are constantly evolving, all knowledge graphs inherently suffer from incompleteness as well as errors in the information they hold. This thesis investigates the challenges encountered during knowledge graph construction and proposes techniques for their curation (a.k.a. refinement) including the correction of semantic ambiguities and the completion of missing facts. Firstly, we leverage existing approaches for the automatic construction of a knowledge graph in the art domain with open information extraction techniques and analyse their limitations. In particular, we focus on the challenging task of named entity recognition for artwork titles and show empirical evidence of performance improvement with our proposed solution for the generation of annotated training data. Towards the curation of existing knowledge graphs, we identify the issue of polysemous relations that represent different semantics based on the context. Having concrete semantics for relations is important for downstream appli- cations (e.g. question answering) that are supported by knowledge graphs. Therefore, we define the novel task of finding fine-grained relation semantics in knowledge graphs and propose FineGReS, a data-driven technique that discovers potential sub-relations with fine-grained meaning from existing pol- ysemous relations. We leverage knowledge representation learning methods that generate low-dimensional vectors (or embeddings) for knowledge graphs to capture their semantics and structure. The efficacy and utility of the proposed technique are demonstrated by comparing it with several baselines on the entity classification use case. Further, we explore the semantic representations in knowledge graph embed- ding models. In the past decade, these models have shown state-of-the-art results for the task of link prediction in the context of knowledge graph comple- tion. In view of the popularity and widespread application of the embedding techniques not only for link prediction but also for different semantic tasks, this thesis presents a critical analysis of the embeddings by quantitatively measuring their semantic capabilities. We investigate and discuss the reasons for the shortcomings of embeddings in terms of the characteristics of the underlying knowledge graph datasets and the training techniques used by popular models. Following up on this, we propose ReasonKGE, a novel method for generating semantically enriched knowledge graph embeddings by taking into account the semantics of the facts that are encapsulated by an ontology accompanying the knowledge graph. With a targeted, reasoning-based method for generating negative samples during the training of the models, ReasonKGE is able to not only enhance the link prediction performance, but also reduce the number of semantically inconsistent predictions made by the resultant embeddings, thus improving the quality of knowledge graphs. N2 - Wissensgraphen sind strukturierte Wissenssammlungen, die Fakten über die allgemeine Welt oder eine bestimmte Dom¨ane in Form von Entitäten und deren Beziehungen speichern. Aufgrund der Heterogenität der Anwendungsfälle, für die sie verwendet werden, besteht ein Bedarf an der automatischen Erstellung von domänenspezifischen Wissensgraphen aus Texten. Obwohl es viele Forschungsbem¨uhungen in Richtung offener Informationsextraktion für die automatische Konstruktion von Wissensgraphen gegeben hat, sind diese Techniken in domänenspezifischen Umgebungen nicht sehr leistungsfähig. Darüber hinaus leiden alle Wissensgraphen, unabhängig davon, ob sie automatisch aus spezifischen Texten oder auf der Grundlage realer Fakten, die sich ständig weiterentwickeln, konstruiert werden, unter Unvollständigkeit und Fehlern in den darin enthaltenen Informationen. Diese Arbeit untersucht die Herausforderungen, die bei der Konstruktion von Wissensgraphen auftreten, und schlägt Techniken zu ihrer Kuratierung (auch bekannt als Verfeinerung) vor, einschließlich der Korrektur semantischer Mehrdeutigkeiten und der Vervollständigung fehlender Fakten. Zunächst nutzen wir bestehende Ansätze für die automatische Erstellung eines Wissensgraphen im Kunstbereich mit offenen Informationsextraktionstechniken und analysieren deren Grenzen. Insbesondere konzentrieren wir uns auf die anspruchsvolle Aufgabe der Named Entity Recognition für Kunstwerke und zeigen empirische Belege für eine Leistungsverbesserung mit der von uns vorgeschlagenen Lösung für die Generierung von annotierten Trainingsdaten. Im Hinblick auf die Kuratierung bestehender Wissensgraphen identifizieren wir das Problem polysemer Relationen, die je nach Kontext unterschiedliche Semantiken repräsentieren. Konkrete Semantiken für Relationen sind wichtig für nachgelagerte Anwendungen (z.B. Fragenbeantwortung), die durch Wissensgraphen unterstützt werden. Daher definieren wir die neuartige Aufgabe, feinkörnige Relationssemantiken in Wissensgraphen zu finden und schlagen FineGReS vor, eine datengesteuerte Technik, die eine datengesteuerte Technik, die potenzielle Unterbeziehungen mit feinkörniger Bedeutung aus bestehenden polysemen Beziehungen entdeckt. Wir nutzen Lernmethoden zur Wissensrepräsentation, die niedrigdimensionale Vektoren (oder Einbettungen) für Wissensgraphen erzeugen, um deren Semantik und Struktur zu erfassen. Die Wirksamkeit und Nützlichkeit der vorgeschlagenen Technik wird durch den Vergleich mit verschiedenen Basisverfahren im Anwendungsfall der Entitätsklassifizierung demonstriert. Darüber hinaus untersuchen wir die semantischen Repräsentationen in Modellen zur Einbettung von Wissensgraphen. In den letzten zehn Jahren haben diese Modelle in den letzten zehn Jahren die besten Ergebnisse bei der Vorhersage von Links im Zusammenhang mit der Vervollständigung von Wissensgraphen erzielt. Angesichts der Popularität und der weit verbreiteten Anwendung der Einbettungstechniken nicht nur für die Linkvorhersage, sondern auch für andere semantische Aufgaben, wird in dieser Arbeit eine kritische Analyse der Einbettungen durch quantitative Messung ihrer semantischen Fähigkeiten vorgenommen. Wir untersuchen und diskutieren die Gründe für die Unzulänglichkeiten von Einbettungen in Bezug auf die Eigenschaften der zugrundeliegenden Wissensgraphen-Datensätze und die von den populären Modellen verwendeten Trainingstechniken. Darauf aufbauend schlagen wir ReasonKGE vor, eine neuartige Methode zur Erzeugung semantisch angereicherter Wissensgrapheneinbettungen durch Berücksichtigung der Semantik der Fakten, die durch eine den Wissensgraphen begleitende Ontologie gekapselt sind. Mit einer gezielten, schlussfolgernden Methode zur Erzeugung von Negativproben während des Trainings der Modelle ist ReasonKGE in der Lage, nicht nur die Leistung der Link-Vorhersage zu verbessern, sondern auch die Anzahl der semantisch inkonsistenten Vorhersagen der resultierenden Einbettungen zu reduzieren und damit die Qualität der Wissensgraphen zu verbessern. KW - knowledge graphs KW - embeddings KW - knowledge graph construction KW - knowledge graph refinement KW - domain-specific knowledge graphs KW - named entity recognition KW - semantic representations KW - domänenspezifisches Wissensgraphen KW - Einbettungen KW - Konstruktion von Wissensgraphen KW - Wissensgraphen Verfeinerung KW - Wissensgraphen KW - Named-Entity-Erkennung KW - semantische Repräsentationen Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-612240 ER - TY - CHAP A1 - Esveld, Selma van A1 - Vries, Nardo de A1 - Becchetti, Sibilla A1 - Dopper, Sofia A1 - Valkenburg, Willem van A1 - Carlon, May Kristine Jonson A1 - Yokoi, Kensuke A1 - Gayed, John Maurice A1 - Suyama, Hiroshi A1 - Cross, Jeffrey Scott A1 - Jin, Tonje A1 - Xue, Wei A1 - Bruillard, Éric A1 - Steinbeck, Hendrik A1 - Meinel, Christoph A1 - Özdemir, Paker Doğu A1 - Can Bayer, Burak A1 - Mercan, Duygu A1 - Buyurucu, Gamze A1 - Haugsbakken, Halvdan A1 - Hagelia, Marianne A1 - Ebner, Martin A1 - Edelsbrunner, Sarah A1 - Hohla-Sejkora, Katharina A1 - Lipp, Silvia A1 - Schön, Sandra A1 - Xiaoxiao, Wang A1 - Shuangshuang, Guo A1 - Morales-Chan, Miguel A1 - Amado-Salvatierra, Héctor R. A1 - Hernández-Rizzardini, Rocael A1 - Egloffstein, Marc A1 - Hünemohr, Holger A1 - Ifenthaler, Dirk A1 - Dixon, Fred A1 - Trabucchi, Stefania A1 - Khaneboubi, Mehdi A1 - Giannatelli, Ada A1 - Tomasini, Alessandra A1 - Staubitz, Thomas A1 - Serth, Sebastian A1 - Thomas, Max A1 - Koschutnig-Ebner, Markus A1 - Rampelt, Florian A1 - Stetten, Alexander von A1 - Wittke, Andreas A1 - Theeraroungchaisri, Anuchai A1 - Thammetar, Thapanee A1 - Duangchinda, Vorasuang A1 - Khlaisang, Jintavee A1 - Mair, Bettina A1 - Steinkellner, Iris A1 - Stojcevic, Ivana A1 - Zwiauer, Charlotte A1 - Thirouard, Maria A1 - Villèsbrunne, Marie de la A1 - Bernaert, Oliver A1 - Nohr, Magnus A1 - Alario Hoyos, Carlos A1 - Delgado Kloos, Carlos A1 - Kiendl, Doris A1 - Terzieva, Liliya A1 - Concia, Francesca A1 - Distler, Petr A1 - Law, Gareth A1 - Macerata, Elena A1 - Mariani, Mario A1 - Mossini, Eros A1 - Negrin, Maddalena A1 - Štrok, Marko A1 - Neuböck, Kristina A1 - Linschinger, Nadine A1 - Lorenz, Anja A1 - Bock, Stefanie A1 - Schulte-Ostermann, Juleka A1 - Moura Santos, Ana A1 - Corti, Paola A1 - Costa, Luis Felipe Coimbra A1 - Utunen, Heini A1 - Attias, Melissa A1 - Tokar, Anna A1 - Kennedy, Eileen A1 - Laurillard, Diana A1 - Zeitoun, Samar A1 - Wasilewski, Julie A1 - Shlaka, Souhad A1 - Ouahib, Sara A1 - Berrada, Khalid A1 - Dietz, Michael A1 - Roth, Dennis ED - Meinel, Christoph ED - Schweiger, Stefanie ED - Staubitz, Thomas ED - Conrad, Robert ED - Alario Hoyos, Carlos ED - Ebner, Martin ED - Sancassani, Susanna ED - Żur, Agnieszka ED - Friedl, Christian ED - Halawa, Sherif ED - Gamage, Dilrukshi ED - Cross, Jeffrey ED - Jonson Carlon, May Kristine ED - Deville, Yves ED - Gaebel, Michael ED - Delgado Kloos, Carlos ED - von Schmieden, Karen T1 - EMOOCs 2023 BT - Post-Covid Prospects for Massive Open Online Courses - Boost or Backlash? N2 - From June 14 to June 16, 2023, Hasso Plattner Institute, Potsdam, hosted the eighth European MOOC Stakeholder Summit (EMOOCs 2023). The pandemic is fortunately over. It has once again shown how important digital education is. How well-prepared a country was could be seen in our schools, universities, and companies. In different countries, the problems manifested themselves differently. The measures and approaches to solving the problems varied accordingly. Digital education, whether micro-credentials, MOOCs, blended learning formats, or other e-learning tools, received a major boost. EMOOCs 2023 focusses on the effects of this emergency situation. How has it affected the development and delivery of MOOCs and other e-learning offerings all over Europe? Which projects can serve as models for successful digital learning and teaching? Which roles can MOOCs and micro-credentials bear in the current business transformation? Is there a backlash to the routine we knew from pre-Corona times? Or have many things become firmly established in the meantime, e.g. remote work, hybrid conferences, etc.? Furthermore, EMOOCs 2023 has a closer look at the development and formalization of digital learning. Micro-credentials are just the starting point. Further steps in this direction would be complete online study programs or full online universities. Another main topic is the networking of learning offers and the standardization of formats and metadata. Examples of fruitful cooperations are the MOOChub, the European MOOC Consortium, and the Common Micro-Credential Framework. The learnings, derived from practical experience and research, are explored in EMOOCs 2023 in four tracks and additional workshops, covering various aspects of this field. In this publication, we present papers from the conference’s Research & Experience Track, the Business Track and the International Track. N2 - Vom 14. bis 16. Juni 2023 fand am Hasso-Plattner-Institut in Potsdam der achte European MOOC Stakeholder Summit (EMOOCs 2023) statt. Die Pandemie ist zum Glück vorbei. Sie hat einmal mehr gezeigt, wie wichtig digitale Bildung ist. Wie gut ein Land darauf vorbereitet war, zeigte sich in unseren Schulen, Universitäten und Unternehmen. In den verschiedenen Ländern haben sich die Probleme unterschiedlich manifestiert. Entsprechend unterschiedlich waren auch die Maßnahmen und Lösungsansätze. Die digitale Bildung, ob Micro-Credentials, MOOCs, Blended-Learning-Formate oder andere E-Learning-Tools, erhielt einen großen Schub. EMOOCs 2023 befasst sich mit den Auswirkungen dieser Notsituation. Wie hat sie die Entwicklung und Bereitstellung von MOOCs und anderen E-Learning-Angeboten in ganz Europa beeinflusst? Welche Projekte können als Modelle für erfolgreiches digitales Lernen und Lehren dienen? Welche Rolle können MOOCs und Micro-Credentials bei der aktuellen Transformation der Wirtschaft spielen? Gibt es eine Rückbesinnung auf die Routine, die wir aus der Zeit vor Corona kennen? Oder haben sich viele Dinge inzwischen fest etabliert, z.B. Remote Work, hybride Konferenzen, etc. Darüber hinaus wirft EMOOCs 2023 einen genaueren Blick auf die Entwicklung und Formalisierung des digitalen Lernens. Microcredentials sind nur der Anfang. Weitere Schritte in diese Richtung wären komplette Online-Studiengänge oder vollständige Online-Universitäten. Ein weiteres Schwerpunktthema ist die Vernetzung von Lernangeboten und die Standardisierung von Formaten und Metadaten. Beispiele für fruchtbare Kooperationen sind der MOOChub, das European MOOC Consortium und das Common Micro-Credential Framework. Die aus der Praxis und der Forschung gewonnenen Erkenntnisse werden auf der EMOOCs 2023 in vier Tracks und zusätzlichen Workshops zu verschiedenen Aspekten des Themas vertieft. In dieser Publikation stellen wir Beiträge aus dem Research & Experience Track, dem Business Track und dem International Track vor. KW - MOOC KW - digital education KW - e-learning KW - online course design KW - online course creation KW - micro-credential KW - micro degree KW - online teaching KW - MOOC KW - Onlinekurs KW - Digitale Bildung KW - Online-Lehre KW - Kursdesign KW - Onlinekurs-Produktion KW - Micro Degree Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-576450 ER - TY - JOUR A1 - van der Aa, Han A1 - Leopold, Henrik A1 - Weidlich, Matthias T1 - Partial order resolution of event logs for process conformance checking JF - Decision support systems : DSS N2 - While supporting the execution of business processes, information systems record event logs. Conformance checking relies on these logs to analyze whether the recorded behavior of a process conforms to the behavior of a normative specification. A key assumption of existing conformance checking techniques, however, is that all events are associated with timestamps that allow to infer a total order of events per process instance. Unfortunately, this assumption is often violated in practice. Due to synchronization issues, manual event recordings, or data corruption, events are only partially ordered. In this paper, we put forward the problem of partial order resolution of event logs to close this gap. It refers to the construction of a probability distribution over all possible total orders of events of an instance. To cope with the order uncertainty in real-world data, we present several estimators for this task, incorporating different notions of behavioral abstraction. Moreover, to reduce the runtime of conformance checking based on partial order resolution, we introduce an approximation method that comes with a bounded error in terms of accuracy. Our experiments with real-world and synthetic data reveal that our approach improves accuracy over the state-of-the-art considerably. KW - process mining KW - conformance checking KW - partial order resolution KW - data KW - uncertainty Y1 - 2020 U6 - https://doi.org/10.1016/j.dss.2020.113347 SN - 0167-9236 SN - 1873-5797 VL - 136 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - THES A1 - Quinzan, Francesco T1 - Combinatorial problems and scalability in artificial intelligence N2 - Modern datasets often exhibit diverse, feature-rich, unstructured data, and they are massive in size. This is the case of social networks, human genome, and e-commerce databases. As Artificial Intelligence (AI) systems are increasingly used to detect pattern in data and predict future outcome, there are growing concerns on their ability to process large amounts of data. Motivated by these concerns, we study the problem of designing AI systems that are scalable to very large and heterogeneous data-sets. Many AI systems require to solve combinatorial optimization problems in their course of action. These optimization problems are typically NP-hard, and they may exhibit additional side constraints. However, the underlying objective functions often exhibit additional properties. These properties can be exploited to design suitable optimization algorithms. One of these properties is the well-studied notion of submodularity, which captures diminishing returns. Submodularity is often found in real-world applications. Furthermore, many relevant applications exhibit generalizations of this property. In this thesis, we propose new scalable optimization algorithms for combinatorial problems with diminishing returns. Specifically, we focus on three problems, the Maximum Entropy Sampling problem, Video Summarization, and Feature Selection. For each problem, we propose new algorithms that work at scale. These algorithms are based on a variety of techniques, such as forward step-wise selection and adaptive sampling. Our proposed algorithms yield strong approximation guarantees, and the perform well experimentally. We first study the Maximum Entropy Sampling problem. This problem consists of selecting a subset of random variables from a larger set, that maximize the entropy. By using diminishing return properties, we develop a simple forward step-wise selection optimization algorithm for this problem. Then, we study the problem of selecting a subset of frames, that represent a given video. Again, this problem corresponds to a submodular maximization problem. We provide a new adaptive sampling algorithm for this problem, suitable to handle the complex side constraints imposed by the application. We conclude by studying Feature Selection. In this case, the underlying objective functions generalize the notion of submodularity. We provide a new adaptive sequencing algorithm for this problem, based on the Orthogonal Matching Pursuit paradigm. Overall, we study practically relevant combinatorial problems, and we propose new algorithms to solve them. We demonstrate that these algorithms are suitable to handle massive datasets. However, our analysis is not problem-specific, and our results can be applied to other domains, if diminishing return properties hold. We hope that the flexibility of our framework inspires further research into scalability in AI. N2 - Moderne Datensätze bestehen oft aus vielfältigen, funktionsreichen und unstrukturierten Daten, die zudem sehr groß sind. Dies gilt insbesondere für soziale Netzwerke, das menschliche Genom und E-Commerce Datenbanken. Mit dem zunehmenden Einsatz von künstlicher Intelligenz (KI) um Muster in den Daten zu erkennen und künftige Ergebnisse vorherzusagen, steigen auch die Bedenken hinsichtlich ihrer Fähigkeit große Datenmengen zu verarbeiten. Aus diesem Grund untersuchen wir das Problem der Entwicklung von KI-Systemen, die auf große und heterogene Datensätze skalieren. Viele KI-Systeme müssen während ihres Einsatzes kombinatorische Optimierungsprobleme lösen. Diese Optimierungsprobleme sind in der Regel NP-schwer und können zusätzliche Nebeneinschränkungen aufwiesen. Die Zielfunktionen dieser Probleme weisen jedoch oft zusätzliche Eigenschaften auf. Diese Eigenschaften können genutzt werden, um geeignete Optimierungsalgorithmen zu entwickeln. Eine dieser Eigenschaften ist das wohluntersuchte Konzept der Submodularität, das das Konzept des abnehmende Erträge beschreibt. Submodularität findet sich in vielen realen Anwendungen. Darüber hinaus weisen viele relevante An- wendungen Verallgemeinerungen dieser Eigenschaft auf. In dieser Arbeit schlagen wir neue skalierbare Algorithmen für kombinatorische Probleme mit abnehmenden Erträgen vor. Wir konzentrieren uns hierbei insbesondere auf drei Prob- leme: dem Maximum-Entropie-Stichproben Problem, der Videozusammenfassung und der Feature Selection. Für jedes dieser Probleme schlagen wir neue Algorithmen vor, die gut skalieren. Diese Algorithmen basieren auf verschiedenen Techniken wie der schrittweisen Vorwärtsauswahl und dem adaptiven sampling. Die von uns vorgeschlagenen Algorithmen bieten sehr gute Annäherungsgarantien und zeigen auch experimentell gute Leistung. Zunächst untersuchen wir das Maximum-Entropy-Sampling Problem. Dieses Problem besteht darin, zufällige Variablen aus einer größeren Menge auszuwählen, welche die Entropie maximieren. Durch die Verwendung der Eigenschaften des abnehmenden Ertrags entwickeln wir einen einfachen forward step-wise selection Optimierungsalgorithmus für dieses Problem. Anschließend untersuchen wir das Problem der Auswahl einer Teilmenge von Bildern, die ein bestimmtes Video repräsentieren. Dieses Problem entspricht einem submodularen Maximierungsproblem. Hierfür stellen wir einen neuen adaptiven Sampling-Algorithmus für dieses Problem zur Verfügung, das auch komplexe Nebenbedingungen erfüllen kann, welche durch die Anwendung entstehen. Abschließend untersuchen wir die Feature Selection. In diesem Fall verallgemeinern die zugrundeliegenden Zielfunktionen die Idee der submodularität. Wir stellen einen neuen adaptiven Sequenzierungsalgorithmus für dieses Problem vor, der auf dem Orthogonal Matching Pursuit Paradigma basiert. Insgesamt untersuchen wir praktisch relevante kombinatorische Probleme und schlagen neue Algorithmen vor, um diese zu lösen. Wir zeigen, dass diese Algorithmen für die Verarbeitung großer Datensätze geeignet sind. Unsere Auswertung ist jedoch nicht problemspezifisch und unsere Ergebnisse lassen sich auch auf andere Bereiche anwenden, sofern die Eigenschaften des abnehmenden Ertrags gelten. Wir hoffen, dass die Flexibilität unseres Frameworks die weitere Forschung im Bereich der Skalierbarkeit im Bereich KI anregt. KW - artificial intelligence KW - scalability KW - optimization KW - Künstliche Intelligenz KW - Optimierung Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-611114 ER - TY - BOOK A1 - Meinel, Christoph A1 - Galbas, Michael A1 - Hagebölling, David T1 - Digitale Souveränität: Erkenntnisse aus dem deutschen Bildungssektor T1 - Digital sovereignty: insights from Germany’s education sector N2 - Digitale Technologien bieten erhebliche politische, wirtschaftliche und gesellschaftliche Chancen. Zugleich ist der Begriff digitale Souveränität zu einem Leitmotiv im deutschen Diskurs über digitale Technologien geworden: das heißt, die Fähigkeit des Staates, seine Verantwortung wahrzunehmen und die Befähigung der Gesellschaft – und des Einzelnen – sicherzustellen, die digitale Transformation selbstbestimmt zu gestalten. Exemplarisch für die Herausforderung in Deutschland und Europa, die Vorteile digitaler Technologien zu nutzen und gleichzeitig Souveränitätsbedenken zu berücksichtigen, steht der Bildungssektor. Er umfasst Bildung als zentrales öffentliches Gut, ein schnell aufkommendes Geschäftsfeld und wachsende Bestände an hochsensiblen personenbezogenen Daten. Davon ausgehend beschreibt der Bericht Wege zur Entschärfung des Spannungsverhältnisses zwischen Digitalisierung und Souveränität auf drei verschiedenen Ebenen – Staat, Wirtschaft und Individuum – anhand konkreter technischer Projekte im Bildungsbereich: die HPI Schul-Cloud (staatliche Souveränität), die MERLOT-Datenräume (wirtschaftliche Souveränität) und die openHPI-Plattform (individuelle Souveränität). N2 - Digital technology offers significant political, economic, and societal opportunities. At the same time, the notion of digital sovereignty has become a leitmotif in German discourse: the state’s capacity to assume its responsibilities and safeguard society’s – and individuals’ – ability to shape the digital transformation in a self-determined way. The education sector is exemplary for the challenge faced by Germany, and indeed Europe, of harnessing the benefits of digital technology while navigating concerns around sovereignty. It encompasses education as a core public good, a rapidly growing field of business, and growing pools of highly sensitive personal data. The report describes pathways to mitigating the tension between digitalization and sovereignty at three different levels – state, economy, and individual – through the lens of concrete technical projects in the education sector: the HPI Schul-Cloud (state sovereignty), the MERLOT data spaces (economic sovereignty), and the openHPI platform (individual sovereignty). T3 - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 156 KW - Digitalisierung KW - digitale Souveränität KW - digitale Bildung KW - HPI Schul-Cloud KW - MERLOT KW - openHPI KW - Europäische Union KW - digitalization KW - digital sovereignty KW - digital education KW - HPI Schul-Cloud KW - MERLOT KW - openHPI KW - European Union Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-595138 SN - 978-3-86956-560-6 SN - 1613-5652 SN - 2191-1665 IS - 156 SP - 1 EP - 29 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Tan, Jing T1 - Multi-Agent Reinforcement Learning for Interactive Decision-Making T1 - Multiagenten Verstärkendes Lernen für Interaktive Entscheidungsfindung N2 - Distributed decision-making studies the choices made among a group of interactive and self-interested agents. Specifically, this thesis is concerned with the optimal sequence of choices an agent makes as it tries to maximize its achievement on one or multiple objectives in the dynamic environment. The optimization of distributed decision-making is important in many real-life applications, e.g., resource allocation (of products, energy, bandwidth, computing power, etc.) and robotics (heterogeneous agent cooperation on games or tasks), in various fields such as vehicular network, Internet of Things, smart grid, etc. This thesis proposes three multi-agent reinforcement learning algorithms combined with game-theoretic tools to study strategic interaction between decision makers, using resource allocation in vehicular network as an example. Specifically, the thesis designs an interaction mechanism based on second-price auction, incentivizes the agents to maximize multiple short-term and long-term, individual and system objectives, and simulates a dynamic environment with realistic mobility data to evaluate algorithm performance and study agent behavior. Theoretical results show that the mechanism has Nash equilibria, is a maximization of social welfare and Pareto optimal allocation of resources in a stationary environment. Empirical results show that in the dynamic environment, our proposed learning algorithms outperform state-of-the-art algorithms in single and multi-objective optimization, and demonstrate very good generalization property in significantly different environments. Specifically, with the long-term multi-objective learning algorithm, we demonstrate that by considering the long-term impact of decisions, as well as by incentivizing the agents with a system fairness reward, the agents achieve better results in both individual and system objectives, even when their objectives are private, randomized, and changing over time. Moreover, the agents show competitive behavior to maximize individual payoff when resource is scarce, and cooperative behavior in achieving a system objective when resource is abundant; they also learn the rules of the game, without prior knowledge, to overcome disadvantages in initial parameters (e.g., a lower budget). To address practicality concerns, the thesis also provides several computational performance improvement methods, and tests the algorithm in a single-board computer. Results show the feasibility of online training and inference in milliseconds. There are many potential future topics following this work. 1) The interaction mechanism can be modified into a double-auction, eliminating the auctioneer, resembling a completely distributed, ad hoc network; 2) the objectives are assumed to be independent in this thesis, there may be a more realistic assumption regarding correlation between objectives, such as a hierarchy of objectives; 3) current work limits information-sharing between agents, the setup befits applications with privacy requirements or sparse signaling; by allowing more information-sharing between the agents, the algorithms can be modified for more cooperative scenarios such as robotics. N2 - Die Verteilte Entscheidungsfindung untersucht Entscheidungen innerhalb einer Gruppe von interaktiven und eigennützigen Agenten. Diese Arbeit befasst sich insbesondere mit der optimalen Folge von Entscheidungen eines Agenten, der das Erreichen eines oder mehrerer Ziele in einer dynamischen Umgebung zu maximieren versucht. Die Optimierung einer verteilten Entscheidungsfindung ist in vielen alltäglichen Anwendungen relevant, z.B. zur Allokation von Ressourcen (Produkte, Energie, Bandbreite, Rechenressourcen etc.) und in der Robotik (heterogene Agenten-Kooperation in Spielen oder Aufträgen) in diversen Feldern wie Fahrzeugkommunikation, Internet of Things, Smart Grid, usw. Diese Arbeit schlägt drei Multi-Agenten Reinforcement Learning Algorithmen kombiniert mit spieltheoretischen Ansätzen vor, um die strategische Interaktion zwischen Entscheidungsträgern zu untersuchen. Dies wird am Beispiel einer Ressourcenallokation in der Fahrzeug-zu-X-Kommunikation (vehicle-to-everything) gezeigt. Speziell wird in der Arbeit ein Interaktionsmechanismus entwickelt, der auf Basis einer Zweitpreisauktion den Agenten zur Maximierung mehrerer kurz- und langfristiger Ziele sowie individueller und Systemziele anregt. Dabei wird eine dynamische Umgebung mit realistischen Mobilitätsdaten simuliert, um die Leistungsfähigkeit des Algorithmus zu evaluieren und das Agentenverhalten zu untersuchen. Eine theoretische Analyse zeigt, dass bei diesem Mechanismus das Nash-Gleichgewicht sowie eine Maximierung von Wohlfahrt und Pareto-optimaler Ressourcenallokation in einer statischen Umgebung vorliegen. Empirische Untersuchungen ergeben, dass in einer dynamischen Umgebung der vorgeschlagene Lernalgorithmus den aktuellen Stand der Technik bei ein- und mehrdimensionaler Optimierung übertrifft, und dabei sehr gut auch auf stark abweichende Umgebungen generalisiert werden kann. Speziell mit dem langfristigen mehrdimensionalen Lernalgorithmus wird gezeigt, dass bei Berücksichtigung von langfristigen Auswirkungen von Entscheidungen, als auch durch einen Anreiz zur Systemgerechtigkeit, die Agenten in individuellen als auch Systemzielen bessere Ergebnisse liefern, und das auch, wenn ihre Ziele privat, zufällig und zeitveränderlich sind. Weiter zeigen die Agenten Wettbewerbsverhalten, um ihre eigenen Ziele zu maximieren, wenn die Ressourcen knapp sind, und kooperatives Verhalten, um Systemziele zu erreichen, wenn die Ressourcen ausreichend sind. Darüber hinaus lernen sie die Ziele des Spiels ohne vorheriges Wissen über dieses, um Startschwierigkeiten, wie z.B. ein niedrigeres Budget, zu überwinden. Für die praktische Umsetzung zeigt diese Arbeit auch mehrere Methoden auf, welche die Rechenleistung verbessern können, und testet den Algorithmus auf einem handelsüblichen Einplatinencomputer. Die Ergebnisse zeigen die Durchführbarkeit von inkrementellem Lernen und Inferenz innerhalb weniger Millisekunden auf. Ausgehend von den Ergebnissen dieser Arbeit könnten sich verschiedene Forschungsfragen anschließen: 1) Der Interaktionsmechanismus kann zu einer Doppelauktion verändert und dabei der Auktionator entfernt werden. Dies würde einem vollständig verteilten Ad-Hoc-Netzwerk entsprechen. 2) Die Ziele werden in dieser Arbeit als unabhängig betrachtet. Es könnte eine Korrelation zwischen mehreren Zielen angenommen werden, so wie eine Zielhierarchie. 3) Die aktuelle Arbeit begrenzt den Informationsaustausch zwischen Agenten. Diese Annahme passt zu Anwendungen mit Anforderungen an den Schutz der Privatsphäre oder bei spärlichen Signalen. Indem der Informationsaustausch erhöht wird, könnte der Algorithmus auf stärker kooperative Anwendungen wie z.B. in der Robotik erweitert werden. KW - V2X KW - distributed systems KW - reinforcement learning KW - game theory KW - auction KW - decision making KW - behavioral sciences KW - multi-objective KW - V2X KW - Verteilte Systeme KW - Spieltheorie KW - Auktion KW - Entscheidungsfindung KW - Verhaltensforschung KW - verstärkendes Lernen KW - Multiziel Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-607000 ER - TY - THES A1 - Santuber, Joaquin T1 - Designing for digital justice T1 - Designing for Digital Justice T1 - Diseñar para la justicia digital BT - an entanglement of people, law, and technologies in Chilean courts BT - eine Verflechtung von Menschen, Recht und Technologien in chilenischen Gerichten BT - una maraña de personas, leyes y tecnologías en los tribunales chilenos N2 - At the beginning of 2020, with COVID-19, courts of justice worldwide had to move online to continue providing judicial service. Digital technologies materialized the court practices in ways unthinkable shortly before the pandemic creating resonances with judicial and legal regulation, as well as frictions. A better understanding of the dynamics at play in the digitalization of courts is paramount for designing justice systems that serve their users better, ensure fair and timely dispute resolutions, and foster access to justice. Building on three major bodies of literature —e-justice, digitalization and organization studies, and design research— Designing for Digital Justice takes a nuanced approach to account for human and more-than-human agencies. Using a qualitative approach, I have studied in depth the digitalization of Chilean courts during the pandemic, specifically between April 2020 and September 2022. Leveraging a comprehensive source of primary and secondary data, I traced back the genealogy of the novel materializations of courts’ practices structured by the possibilities offered by digital technologies. In five (5) cases studies, I show in detail how the courts got to 1) work remotely, 2) host hearings via videoconference, 3) engage with users via social media (i.e., Facebook and Chat Messenger), 4) broadcast a show with judges answering questions from users via Facebook Live, and 5) record, stream, and upload judicial hearings to YouTube to fulfil the publicity requirement of criminal hearings. The digitalization of courts during the pandemic is characterized by a suspended normativity, which makes innovation possible yet presents risks. While digital technologies enabled the judiciary to provide services continuously, they also created the risk of displacing traditional judicial and legal regulation. Contributing to liminal innovation and digitalization research, Designing for Digital Justice theorizes four phases: 1) the pre-digitalization phase resulting in the development of regulation, 2) the hotspot of digitalization resulting in the extension of regulation, 3) the digital innovation redeveloping regulation (moving to a new, preliminary phase), and 4) the permanence of temporal practices displacing regulation. Contributing to design research Designing for Digital Justice provides new possibilities for innovation in the courts, focusing at different levels to better address tensions generated by digitalization. Fellow researchers will find in these pages a sound theoretical advancement at the intersection of digitalization and justice with novel methodological references. Practitioners will benefit from the actionable governance framework Designing for Digital Justice Model, which provides three fields of possibilities for action to design better justice systems. Only by taking into account digital, legal, and social factors can we design better systems that promote access to justice, the rule of law, and, ultimately social peace. N2 - Durch COVID-19 mussten zu Beginn des Jahres 2020 die Gerichte weltweit, um ihren Dienst fortzusetzen, Onlinekommunikation und digitale Technologien nutzen. Die digitalen Technologien haben die Gerichtspraktiken in einer Weise verändert, die kurz vor der Pandemie noch undenkbar war, was zu Resonanzen mit der Rechtsprechung und der gesetzlichen Regelung sowie zu Reibungen führte. Ein besseres Verständnis der Dynamik, die bei der Digitalisierung von Gerichten im Spiel ist, ist von entscheidender Bedeutung für die Gestaltung von Justizsystemen, die ihren Nutzern besser dienen, faire und zeitnahe Streitbeilegung gewährleisten und den Zugang zur Justiz und zur Rechtsstaatlichkeit fördern. Aufbauend auf den drei großen Themenkomplexen E-Justiz, Digitalisierung und Organisationen sowie Designforschung verfolgt „Designing for Digital Justice“ einen nuancierten Ansatz, um menschliche und nicht-menschliche Akteure zu berücksichtigen. Mit Hilfe eines qualitativen Forschungsansatzes habe ich die Digitalisierung der chilenischen Gerichte während der Pandemie, insbesondere im Zeitraum von April 2020 und September 2022, eingehend untersucht. Auf der Grundlage einer umfassenden Quelle von Primär- und Sekundärdaten habe ich die Genealogie der neuartigen Materialisierung von Gerichtspraktiken zurückverfolgt, die durch die Möglichkeiten der digitalen Technologien strukturiert wurden. In fünf (5) Fallstudien zeige ich im Detail, wie die Gerichte 1) aus der Ferne arbeiten, 2) Anhörungen per Videokonferenz abhalten, 3) mit Nutzern über soziale Medien (beispielsweise Facebook und Chat Messenger) in Kontakt treten, 4) eine Sendung mit Richtern, die Fragen von Nutzern beantworten, über Facebook Live ausstrahlen und 5) Gerichtsverhandlungen aufzeichnen, streamen und auf YouTube hochladen, um die Anforderungen an die Öffentlichkeit von Strafverhandlungen zu erfüllen. Hierbei zeigt sich, dass digitale Technologien der Justiz zwar eine kontinuierliche Bereitstellung von Dienstleistungen ermöglichten. Sie bergen aber auch die Gefahr, dass sie die traditionelle gerichtliche und rechtliche Regulierung verdrängen. Als Beitrag zum Forschungsstrom zu „Liminal Innovation“ und Digitalisierung theoretisiert „Designing for Digital Justice“ vier Phasen: 1) Vor-Digitalisierung, die zur Entwicklung von Regulierung führt, 2) der Hotspot der Digitalisierung, der zur Ausweitung der Regulierung führt, 3) digitale Innovation, die die Regulierung neu entwickelt (Übergang zu einer neuen, provisorischen Phase) und 4) die Permanenz der temporären Praktiken, die die Regulierung verdrängt. Als Beitrag zur Designforschung bietet „Designing for Digital Justice“ neue Möglichkeiten für die Gestaltung von Justizsystemen, indem es Spannungen und Interventionsebenen miteinander verbindet. Forscherkolleg*innen finden auf diesen Seiten eine fundierte theoretische Weiterentwicklung an der Schnittstelle von Digitalisierung und Gerechtigkeit sowie neue methodische Hinweise. Praktiker sollen von dem Handlungsrahmen „Designing for Digital Justice Model“ profitieren, der drei Handlungsfelder für die Gestaltung besserer Justizsysteme bietet. Nur wenn wir die digitalen, rechtlichen und sozialen Akteure berücksichtigen, können wir bessere Systeme entwerfen, die sich für den Zugang zur Justiz, die Rechtsstaatlichkeit und letztlich den sozialen Frieden einsetzen. N2 - A principios de 2020, con la COVID-19, los tribunales de justicia de todo el mundo tuvieron que ponerse en línea para continuar con el servicio. Las tecnologías digitales materializaron las prácticas de los tribunales de formas impensables poco antes de la pandemia, creando resonancias con la regulación judicial y legal, así como fricciones. Comprender mejor las dinámicas en juego en la digitalización de los tribunales es primordial para diseñar sistemas de justicia que sirvan mejor a sus usuarios, garanticen una resolución de conflictos justa y oportuna y fomenten el acceso a la justicia. Sobre la base de tres grandes temas en la literatura -justicia electrónica, digitalización y organizaciones, e investigación del diseño-, Designing for Digital Justice adopta un enfoque matizado para tener en cuenta los organismos humanos y más que humanos. Utilizando un enfoque cualitativo, he estudiado en profundidad la digitalización de los tribunales chilenos durante la pandemia, concretamente entre abril de 2020 y septiembre de 2022. Aprovechando una amplia fuente de datos primarios y secundarios, he rastreado la genealogía de las nuevas materializaciones de las prácticas de los tribunales estructuradas por las posibilidades que ofrecen las tecnologías digitales. En cinco (5) estudios de caso, muestro en detalle cómo los tribunales llegaron a 1) trabajar a distancia, 2) celebrar audiencias por videoconferencia, 3) relacionarse con los usuarios a través de las redes sociales (es decir, Facebook y Chat Messenger), 4) emitir un espectáculo con jueces que responden a las preguntas de los usuarios a través de Facebook Live, y 5) grabar, transmitir y subir las audiencias judiciales a YouTube para cumplir con el requisito de publicidad de las audiencias penales. La digitalización de los tribunales durante la pandemia se caracteriza por una normatividad suspendida, que posibilita la innovación, pero presenta riesgos. Si bien las tecnologías digitales permitieron al poder judicial prestar servicios de forma continua, también crearon el riesgo de desplazar la normativa judicial y legal tradicional. Contribuyendo a la teoría de la innovación liminar y digitalización, Designing for Digital Justice teoriza cuatro fases: 1) la fase de pre-digitalización que da lugar al desarrollo de la regulación, 2) el hotspot de digitalización que da lugar a la ampliación de la regulación, 3) la innovación liminal que vuelve a desarrollar la regulación (pasando a una nueva fase preliminar), y 4) la permanencia de prácticas temporales que desplaza la regulación. Contribuyendo a la investigación sobre el diseño, Designing for Digital Justice ofrece nuevas posibilidades de intervención para el diseño de la justicia, conectando las tensiones y los niveles para intervenir en ellos. Los colegas investigadores encontrarán en estas páginas un sólido avance teórico en la intersección de la digitalización y la justicia y novedosas referencias metodológicas. Los profesionales se beneficiarán del marco de gobernanza Designing for Digital Justice Model, que ofrece tres campos de posibilidades de actuación para diseñar mejores sistemas de justicia. Sólo teniendo en cuenta las agencias digitales, jurídicas y sociales podremos diseñar mejores sistemas que se comprometan con el acceso a la justicia, el Estado de Derecho y, en última instancia, la paz social. KW - digitalisation KW - courts of justice KW - COVID-19 KW - Chile KW - online courts KW - design KW - law KW - organization studies KW - innovation KW - COVID-19 KW - Chile KW - Gerichtsbarkeit KW - Design KW - Digitalisierung KW - Innovation KW - Recht KW - Online-Gerichte KW - Organisationsstudien KW - COVID-19 KW - Chile KW - tribunales de justicia KW - diseño KW - digitalización KW - innovación KW - Derecho KW - tribunales en línea KW - estudios de organización Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-604178 ER - TY - THES A1 - Sakizloglou, Lucas T1 - Evaluating temporal queries over history-aware architectural runtime models T1 - Ausführung temporaler Anfragen über geschichtsbewusste Architektur-Laufzeitmodelle N2 - In model-driven engineering, the adaptation of large software systems with dynamic structure is enabled by architectural runtime models. Such a model represents an abstract state of the system as a graph of interacting components. Every relevant change in the system is mirrored in the model and triggers an evaluation of model queries, which search the model for structural patterns that should be adapted. This thesis focuses on a type of runtime models where the expressiveness of the model and model queries is extended to capture past changes and their timing. These history-aware models and temporal queries enable more informed decision-making during adaptation, as they support the formulation of requirements on the evolution of the pattern that should be adapted. However, evaluating temporal queries during adaptation poses significant challenges. First, it implies the capability to specify and evaluate requirements on the structure, as well as the ordering and timing in which structural changes occur. Then, query answers have to reflect that the history-aware model represents the architecture of a system whose execution may be ongoing, and thus answers may depend on future changes. Finally, query evaluation needs to be adequately fast and memory-efficient despite the increasing size of the history---especially for models that are altered by numerous, rapid changes. The thesis presents a query language and a querying approach for the specification and evaluation of temporal queries. These contributions aim to cope with the challenges of evaluating temporal queries at runtime, a prerequisite for history-aware architectural monitoring and adaptation which has not been systematically treated by prior model-based solutions. The distinguishing features of our contributions are: the specification of queries based on a temporal logic which encodes structural patterns as graphs; the provision of formally precise query answers which account for timing constraints and ongoing executions; the incremental evaluation which avoids the re-computation of query answers after each change; and the option to discard history that is no longer relevant to queries. The query evaluation searches the model for occurrences of a pattern whose evolution satisfies a temporal logic formula. Therefore, besides model-driven engineering, another related research community is runtime verification. The approach differs from prior logic-based runtime verification solutions by supporting the representation and querying of structure via graphs and graph queries, respectively, which is more efficient for queries with complex patterns. We present a prototypical implementation of the approach and measure its speed and memory consumption in monitoring and adaptation scenarios from two application domains, with executions of an increasing size. We assess scalability by a comparison to the state-of-the-art from both related research communities. The implementation yields promising results, which pave the way for sophisticated history-aware self-adaptation solutions and indicate that the approach constitutes a highly effective technique for runtime monitoring on an architectural level. N2 - In der modellgetriebenen Entwicklung wird die Adaptation großer Softwaresysteme mit dynamischer Struktur durch Architektur-Laufzeitmodelle ermöglicht. Ein solches Modell stellt einen abstrakten Zustand des Systems als einen Graphen von interagierenden Komponenten dar. Jede relevante Änderung im System spiegelt sich im Modell wider und löst eine Ausführung von Modellanfragen aus, die das Modell nach zu adaptierenden Strukturmustern durchsuchen. Diese Arbeit konzentriert sich auf eine Art von Laufzeitmodellen, bei denen die Ausdruckskraft des Modells und der Modellanfragen erweitert wird, um vergangene Änderungen und deren Zeitpunkt zu erfassen. Diese geschichtsbewussten Modelle und temporalen Anfragen ermöglichen eine fundiertere Entscheidungsfindung während der Adaptation, da sie die Formulierung von Anforderungen an die Entwicklung des Musters, das adaptiert werden soll, unterstützen. Die Ausführung von temporalen Anfragen während der Adaptation stellt jedoch eine große Herausforderung dar. Zunächst müssen Anforderungen an die Struktur sowie an die Reihenfolge und den Zeitpunkt von Strukturänderungen spezifiziert und evaluiert werden. Weiterhin müssen die Antworten auf die Anfragen berücksichtigen, dass das geschichtsbewusste Modell die Architektur eines Systems darstellt, dessen Ausführung fortlaufend sein kann, sodass die Antworten von zukünftigen Änderungen abhängen können. Schließlich muss die Anfrageausführung trotz der zunehmenden Größe der Historie hinreichend schnell und speichereffizient sein---insbesondere bei Modellen, die durch zahlreiche, schnelle Änderungen verändert werden. In dieser Arbeit werden eine Sprache für die Spezifikation von temporalen Anfragen sowie eine Technik für deren Ausführung vorgestellt. Diese Beiträge zielen darauf ab, die Herausforderungen bei der Ausführung temporaler Anfragen zur Laufzeit zu bewältigen---eine Voraussetzung für ein geschichtsbewusstes Architekturmonitoring und geschichtsbewusste Architekturadaptation, die von früheren modellbasierten Lösungen nicht systematisch behandelt wurde. Die besonderen Merkmale unserer Beiträge sind: die Spezifikation von Anfragen auf der Basis einer temporalen Logik, die strukturelle Muster als Graphen kodiert; die Bereitstellung formal präziser Anfrageantworten, die temporale Einschränkungen und laufende Ausführungen berücksichtigen; die inkrementelle Ausführung, die die Neuberechnung von Abfrageantworten nach jeder Änderung vermeidet; und die Option, Historie zu verwerfen, die für Abfragen nicht mehr relevant ist. Bei der Anfrageausführung wird das Modell nach dem Auftreten eines Musters durchsucht, dessen Entwicklung eine temporallogische Formel erfüllt. Neben der modellgetriebenen Entwicklung ist daher die Laufzeitverifikation ein weiteres verwandtes Forschungsgebiet. Der Ansatz unterscheidet sich von bisherigen logikbasierten Lösungen zur Laufzeitverifikation, indem er die Darstellung und Abfrage von Strukturen über Graphen bzw. Graphanfragen unterstützt, was bei Anfragen mit komplexen Mustern effizienter ist. Wir stellen eine prototypische Implementierung des Ansatzes vor und messen seine Laufzeit und seinen Speicherverbrauch in Monitoring- und Adaptationsszenarien aus zwei Anwendungsdomänen mit Ausführungen von zunehmender Größe. Wir bewerten die Skalierbarkeit durch einen Vergleich mit dem Stand der Technik aus beiden verwandten Forschungsgebieten. Die Implementierung liefert vielversprechende Ergebnisse, die den Weg für anspruchsvolle geschichtsbewusste Selbstadaptationslösungen ebnen und darauf hindeuten, dass der Ansatz eine effektive Technik für das Laufzeitmonitoring auf Architekturebene darstellt. KW - architectural adaptation KW - history-aware runtime models KW - incremental graph query evaluation KW - model-driven software engineering KW - temporal graph queries KW - Architekturadaptation KW - geschichtsbewusste Laufzeit-Modelle KW - inkrementelle Ausführung von Graphanfragen KW - modellgetriebene Softwaretechnik KW - temporale Graphanfragen Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-604396 ER - TY - THES A1 - Lindinger, Jakob T1 - Variational inference for composite Gaussian process models T1 - Variationelle Inferenz für zusammengesetzte Gauß-Prozess Modelle N2 - Most machine learning methods provide only point estimates when being queried to predict on new data. This is problematic when the data is corrupted by noise, e.g. from imperfect measurements, or when the queried data point is very different to the data that the machine learning model has been trained with. Probabilistic modelling in machine learning naturally equips predictions with corresponding uncertainty estimates which allows a practitioner to incorporate information about measurement noise into the modelling process and to know when not to trust the predictions. A well-understood, flexible probabilistic framework is provided by Gaussian processes that are ideal as building blocks of probabilistic models. They lend themself naturally to the problem of regression, i.e., being given a set of inputs and corresponding observations and then predicting likely observations for new unseen inputs, and can also be adapted to many more machine learning tasks. However, exactly inferring the optimal parameters of such a Gaussian process model (in a computationally tractable manner) is only possible for regression tasks in small data regimes. Otherwise, approximate inference methods are needed, the most prominent of which is variational inference. In this dissertation we study models that are composed of Gaussian processes embedded in other models in order to make those more flexible and/or probabilistic. The first example are deep Gaussian processes which can be thought of as a small network of Gaussian processes and which can be employed for flexible regression. The second model class that we study are Gaussian process state-space models. These can be used for time-series modelling, i.e., the task of being given a stream of data ordered by time and then predicting future observations. For both model classes the state-of-the-art approaches offer a trade-off between expressive models and computational properties (e.g. speed or convergence properties) and mostly employ variational inference. Our goal is to improve inference in both models by first getting a deep understanding of the existing methods and then, based on this, to design better inference methods. We achieve this by either exploring the existing trade-offs or by providing general improvements applicable to multiple methods. We first provide an extensive background, introducing Gaussian processes and their sparse (approximate and efficient) variants. We continue with a description of the models under consideration in this thesis, deep Gaussian processes and Gaussian process state-space models, including detailed derivations and a theoretical comparison of existing methods. Then we start analysing deep Gaussian processes more closely: Trading off the properties (good optimisation versus expressivity) of state-of-the-art methods in this field, we propose a new variational inference based approach. We then demonstrate experimentally that our new algorithm leads to better calibrated uncertainty estimates than existing methods. Next, we turn our attention to Gaussian process state-space models, where we closely analyse the theoretical properties of existing methods.The understanding gained in this process leads us to propose a new inference scheme for general Gaussian process state-space models that incorporates effects on multiple time scales. This method is more efficient than previous approaches for long timeseries and outperforms its comparison partners on data sets in which effects on multiple time scales (fast and slowly varying dynamics) are present. Finally, we propose a new inference approach for Gaussian process state-space models that trades off the properties of state-of-the-art methods in this field. By combining variational inference with another approximate inference method, the Laplace approximation, we design an efficient algorithm that outperforms its comparison partners since it achieves better calibrated uncertainties. N2 - Bei Vorhersagen auf bisher ungesehenen Datenpunkten liefern die meisten maschinellen Lernmethoden lediglich Punktprognosen. Dies kann problematisch sein, wenn die Daten durch Rauschen verfälscht sind, z. B. durch unvollkommene Messungen, oder wenn der abgefragte Datenpunkt sich stark von den Daten unterscheidet, mit denen das maschinelle Lernmodell trainiert wurde. Mithilfe probabilistischer Modellierung (einem Teilgebiet des maschinellen Lernens) werden die Vorhersagen der Methoden auf natürliche Weise durch Unsicherheiten ergänzt. Dies erlaubt es, Informationen über Messunsicherheiten in den Modellierungsprozess mit einfließen zu lassen, sowie abzuschätzen, bei welchen Vorhersagen dem Modell vertraut werden kann. Grundlage vieler probabilistischer Modelle bilden Gaußprozesse, die gründlich erforscht und äußerst flexibel sind und daher häufig als Bausteine für größere Modelle dienen. Für Regressionsprobleme, was heißt, von einem Datensatz bestehend aus Eingangsgrößen und zugehörigen Messungen auf wahrscheinliche Messwerte für bisher ungesehene Eingangsgrößen zu schließen, sind Gaußprozesse hervorragend geeignet. Zusätzlich können sie an viele weitere Aufgabenstellungen des maschinellen Lernens angepasst werden. Die Bestimmung der optimalen Parameter eines solchen Gaußprozessmodells (in einer annehmbaren Zeit) ist jedoch nur für Regression auf kleinen Datensätzen möglich. In allen anderen Fällen muss auf approximative Inferenzmethoden zurückgegriffen werden, wobei variationelle Inferenz die bekannteste ist. In dieser Dissertation untersuchen wir Modelle, die Gaußprozesse eingebettet in andere Modelle enthalten, um Letztere flexibler und/oder probabilistisch zu machen. Das erste Beispiel hierbei sind tiefe Gaußprozesse, die man sich als kleines Netzwerk von Gaußprozessen vorstellen kann und die für flexible Regression eingesetzt werden können. Die zweite Modellklasse, die wir genauer analysieren ist die der Gaußprozess-Zustandsraummodelle. Diese können zur Zeitreihenmodellierung verwendet werden, das heißt, um zukünftige Datenpunkte auf Basis eines nach der Zeit geordneten Eingangsdatensatzes vorherzusagen. Für beide genannten Modellklassen bieten die modernsten Ansatze einen Kompromiss zwischen expressiven Modellen und wunschenswerten rechentechnischen Eigenschaften (z. B. Geschwindigkeit oder Konvergenzeigenschaften). Desweiteren wird für die meisten Methoden variationelle Inferenz verwendet. Unser Ziel ist es, die Inferenz für beide Modellklassen zu verbessern, indem wir zunächst ein tieferes Verständnis der bestehenden Ansätze erlangen und darauf aufbauend bessere Inferenzverfahren entwickeln. Indem wir die bestehenden Kompromisse der heutigen Methoden genauer untersuchen, oder dadurch, dass wir generelle Verbesserungen anbieten, die sich auf mehrere Modelle anwenden lassen, erreichen wir dieses Ziel. Wir beginnen die Thesis mit einer umfassender Einführung, die den notwendigen technischen Hintergrund zu Gaußprozessen sowie spärlichen (approximativen und effizienten) Gaußprozessen enthält. Anschließend werden die in dieser Thesis behandelten Modellklassen, tiefe Gaußprozesse und Gaußprozess-Zustandsraummodelle, eingeführt, einschließlich detaillierter Herleitungen und eines theoretischen Vergleichs existierender Methoden. Darauf aufbauend untersuchen wir zuerst tiefe Gaußprozesse genauer und entwickeln dann eine neue Inferenzmethode. Diese basiert darauf, die wünschenswerten Eigenschaften (gute Optimierungseigenschaften gegenüber Expressivität) der modernsten Ansätze gegeneinander abzuwägen. Anschließend zeigen wir experimentell, dass unser neuer Algorithmus zu besser kalibrierten Unsicherheitsabschätzungen als bei bestehenden Methoden führt. Als Nächstes wenden wir uns Gaußprozess-Zustandsraummodelle zu, wo wir zuerst die theoretischen Eigenschaften existierender Ansätze genau analysieren. Wir nutzen das dabei gewonnene Verständnis, um ein neues Inferenzverfahren für Gaußprozess-Zustandsraummodelle einzuführen, welches Effekte auf verschiedenen Zeitskalen berücksichtigt. Für lange Zeitreihen ist diese Methode effizienter als bisherige Ansätze. Darüber hinaus übertrifft sie ihre Vergleichspartner auf Datensätzen, bei denen Effekte auf mehreren Zeitskalen (sich schnell und langsam verändernde Signale) auftreten. Zuletzt schlagen wir ein weiteres neues Inferenzverfahren für Gaußprozess-Zustandsraummodelle vor, das die Eigenschaften der aktuellsten Methoden auf diesem Gebiet gegeneinander abwägt. Indem wir variationelle Inferenz mit einem weiteren approximativen Inferenzverfahren, der Laplace- Approximation, kombinieren, entwerfen wir einen effizienten Algorithmus der seine Vergleichspartner dadurch übertrifft, dass er besser kalibrierte Unsicherheitsvorhersagen erzielt. KW - probabilistic machine learning KW - Gaussian processes KW - variational inference KW - deep Gaussian processes KW - Gaussian process state-space models KW - Gauß-Prozess Zustandsraummodelle KW - Gauß-Prozesse KW - tiefe Gauß-Prozesse KW - probabilistisches maschinelles Lernen KW - variationelle Inferenz Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-604441 ER - TY - THES A1 - Afifi, Haitham T1 - Wireless In-Network Processing for Multimedia Applications T1 - Drahtlose In-Network-Verarbeitung für Multimedia-Anwendungen N2 - With the recent growth of sensors, cloud computing handles the data processing of many applications. Processing some of this data on the cloud raises, however, many concerns regarding, e.g., privacy, latency, or single points of failure. Alternatively, thanks to the development of embedded systems, smart wireless devices can share their computation capacity, creating a local wireless cloud for in-network processing. In this context, the processing of an application is divided into smaller jobs so that a device can run one or more jobs. The contribution of this thesis to this scenario is divided into three parts. In part one, I focus on wireless aspects, such as power control and interference management, for deciding which jobs to run on which node and how to route data between nodes. Hence, I formulate optimization problems and develop heuristic and meta-heuristic algorithms to allocate wireless and computation resources. Additionally, to deal with multiple applications competing for these resources, I develop a reinforcement learning (RL) admission controller to decide which application should be admitted. Next, I look into acoustic applications to improve wireless throughput by using microphone clock synchronization to synchronize wireless transmissions. In the second part, I jointly work with colleagues from the acoustic processing field to optimize both network and application (i.e., acoustic) qualities. My contribution focuses on the network part, where I study the relation between acoustic and network qualities when selecting a subset of microphones for collecting audio data or selecting a subset of optional jobs for processing these data; too many microphones or too many jobs can lessen quality by unnecessary delays. Hence, I develop RL solutions to select the subset of microphones under network constraints when the speaker is moving while still providing good acoustic quality. Furthermore, I show that autonomous vehicles carrying microphones improve the acoustic qualities of different applications. Accordingly, I develop RL solutions (single and multi-agent ones) for controlling these vehicles. In the third part, I close the gap between theory and practice. I describe the features of my open-source framework used as a proof of concept for wireless in-network processing. Next, I demonstrate how to run some algorithms developed by colleagues from acoustic processing using my framework. I also use the framework for studying in-network delays (wireless and processing) using different distributions of jobs and network topologies. N2 - Mit der steigenden Anzahl von Sensoren übernimmt Cloud Computing die Datenverarbeitung vieler Anwendungen. Dies wirft jedoch viele Bedenken auf, z. B. in Bezug auf Datenschutz, Latenzen oder Fehlerquellen. Alternativ und dank der Entwicklung eingebetteter Systeme können drahtlose intelligente Geräte für die lokale Verarbeitung verwendet werden, indem sie ihre Rechenkapazität gemeinsam nutzen und so eine lokale drahtlose Cloud für die netzinterne Verarbeitung schaffen. In diesem Zusammenhang wird eine Anwendung in kleinere Aufgaben unterteilt, so dass ein Gerät eine oder mehrere Aufgaben ausführen kann. Der Beitrag dieser Arbeit zu diesem Szenario gliedert sich in drei Teile. Im ersten Teil konzentriere ich mich auf drahtlose Aspekte wie Leistungssteuerung und Interferenzmanagement um zu entscheiden, welche Aufgaben auf welchem Knoten ausgeführt werden sollen und wie die Daten zwischen den Knoten weitergeleitet werden sollen. Daher formuliere ich Optimierungsprobleme und entwickle heuristische und metaheuristische Algorithmen zur Zuweisung von Ressourcen eines drahtlosen Netzwerks. Um mit mehreren Anwendungen, die um diese Ressourcen konkurrieren, umgehen zu können, entwickle ich außerdem einen Reinforcement Learning (RL) Admission Controller, um zu entscheiden, welche Anwendung zugelassen werden soll. Als Nächstes untersuche ich akustische Anwendungen zur Verbesserung des drahtlosen Durchsatzes, indem ich Mikrofon-Taktsynchronisation zur Synchronisierung drahtloser Übertragungen verwende. Im zweiten Teil arbeite ich mit Kollegen aus dem Bereich der Akustikverarbeitung zusammen, um sowohl die Netzwerk- als auch die Anwendungsqualitäten (d.h. die akustischen) zu optimieren. Mein Beitrag konzentriert sich auf den Netzwerkteil, wo ich die Beziehung zwischen akustischen und Netzwerkqualitäten bei der Auswahl einer Teilmenge von Mikrofonen für die Erfassung von Audiodaten oder der Auswahl einer Teilmenge von optionalen Aufgaben für die Verarbeitung dieser Daten untersuche; zu viele Mikrofone oder zu viele Aufgaben können die Qualität durch unnötige Verzögerungen verringern. Daher habe ich RL-Lösungen entwickelt, um die Teilmenge der Mikrofone unter Netzwerkbeschränkungen auszuwählen, wenn sich der Sprecher bewegt, und dennoch eine gute akustische Qualität gewährleistet. Außerdem zeige ich, dass autonome Fahrzeuge, die Mikrofone mit sich führen, die akustische Qualität verschiedener Anwendungen verbessern. Dementsprechend entwickle ich RL-Lösungen (Einzel- und Multi-Agenten-Lösungen) für die Steuerung dieser Fahrzeuge. Im dritten Teil schließe ich die Lücke zwischen Theorie und Praxis. Ich beschreibe die Eigenschaften meines Open-Source-Frameworks, das als Prototyp für die drahtlose netzinterne Verarbeitung verwendet wird. Anschließend zeige ich, wie einige Algorithmen, die von Kollegen aus der Akustikverarbeitung entwickelt wurden, mit meinem Framework ausgeführt werden können. Außerdem verwende ich das Framework für die Untersuchung von netzinternen Verzögerungen unter Verwendung verschiedener Aufgabenverteilungen und Netzwerktopologien. KW - wireless networks KW - reinforcement learning KW - network optimization KW - Netzoptimierung KW - bestärkendes Lernen KW - drahtloses Netzwerk Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-604371 ER - TY - JOUR A1 - Galka, Andreas A1 - Moontaha, Sidratul A1 - Siniatchkin, Michael T1 - Constrained expectation maximisation algorithm for estimating ARMA models in state space representation JF - EURASIP journal on advances in signal processing N2 - This paper discusses the fitting of linear state space models to given multivariate time series in the presence of constraints imposed on the four main parameter matrices of these models. Constraints arise partly from the assumption that the models have a block-diagonal structure, with each block corresponding to an ARMA process, that allows the reconstruction of independent source components from linear mixtures, and partly from the need to keep models identifiable. The first stage of parameter fitting is performed by the expectation maximisation (EM) algorithm. Due to the identifiability constraint, a subset of the diagonal elements of the dynamical noise covariance matrix needs to be constrained to fixed values (usually unity). For this kind of constraints, so far, no closed-form update rules were available. We present new update rules for this situation, both for updating the dynamical noise covariance matrix directly and for updating a matrix square-root of this matrix. The practical applicability of the proposed algorithm is demonstrated by a low-dimensional simulation example. The behaviour of the EM algorithm, as observed in this example, illustrates the well-known fact that in practical applications, the EM algorithm should be combined with a different algorithm for numerical optimisation, such as a quasi-Newton algorithm. KW - Kalman filtering KW - state space modelling KW - expectation maximisation algorithm Y1 - 2020 U6 - https://doi.org/10.1186/s13634-020-00678-3 SN - 1687-6180 VL - 2020 IS - 1 PB - Springer CY - Heidelberg ER - TY - THES A1 - Traifeh, Hanadi T1 - Design Thinking in the Arab world T1 - Design Thinking in der Arabischen Welt BT - perspectives, challenges and opportunities BT - Perspektiven, Herausforderungen und Potentiale N2 - Design Thinking is a human-centered approach to innovation that has become increasingly popular globally over the last decade. While the spread of Design Thinking is well understood and documented in the Western cultural contexts, particularly in Europe and the US due to the popularity of the Stanford-Potsdam Design Thinking education model, this is not the case when it comes to non-Western cultural contexts. This thesis fills a gap identified in the literature regarding how Design Thinking emerged, was perceived, adopted, and practiced in the Arab world. The culture in that part of the world differs from that of the Western context, which impacts the mindset of people and how they interact with Design Thinking tools and methods. A mixed-methods research approach was followed in which both quantitative and qualitative methods were employed. First, two methods were used in the quantitative phase: a social media analysis using Twitter as a source of data, and an online questionnaire. The results and analysis of the quantitative data informed the design of the qualitative phase in which two methods were employed: ten semi-structured interviews, and participant observation of seven Design Thinking training events. According to the analyzed data, the Arab world appears to have had an early, though relatively weak, and slow, adoption of Design Thinking since 2006. Increasing adoption, however, has been witnessed over the last decade, especially in Saudi Arabia, the United Arab Emirates and Egypt. The results also show that despite its limited spread, Design Thinking has been practiced the most in education, information technology and communication, administrative services, and the non-profit sectors. The way it is being practiced, though, is not fully aligned with how it is being practiced and taught in the US and Europe, as most people in the region do not necessarily believe in all mindset attributes introduced by the Stanford-Potsdam tradition. Practitioners in the Arab world also seem to shy away from the 'wild side' of Design Thinking in particular, and do not fully appreciate the connection between art-design, and science-engineering. This questions the role of the educational institutions in the region since -according to the findings- they appear to be leading the movement in promoting and developing Design Thinking in the Arab world. Nonetheless, it is notable that people seem to be aware of the positive impact of applying Design Thinking in the region, and its potential to bring meaningful transformation. However, they also seem to be concerned about the current cultural, social, political, and economic challenges that may challenge this transformation. Therefore, they call for more awareness and demand to create Arabic, culturally appropriate programs to respond to the local needs. On another note, the lack of Arabic content and local case studies on Design Thinking were identified by several interviewees and were also confirmed by the participant observation as major challenges that are slowing down the spread of Design Thinking or sometimes hampering capacity building in the region. Other challenges that were revealed by the study are: changing the mindset of people, the lack of dedicated Design Thinking spaces, and the need for clear instructions on how to apply Design Thinking methods and activities. The concept of time and how Arabs deal with it, gender management during trainings, and hierarchy and power dynamics among training participants are also among the identified challenges. Another key finding revealed by the study is the confirmation of التفكير التصميمي as the Arabic term to be most widely adopted in the region to refer to Design Thinking, since four other Arabic terms were found to be associated with Design Thinking. Based on the findings of the study, the thesis concludes by presenting a list of recommendations on how to overcome the mentioned challenges and what factors should be considered when designing and implementing culturally-customized Design Thinking training in the Arab region. N2 - Design Thinking ist ein nutzerzentrierter Innovationsansatz, der in den letzten zehn Jahren weltweit an Bekanntheit gewonnen hat. Während die Verbreitung von Design Thinking im westlichen Kulturkreis – insbesondere in Europa und den USA – aufgrund der Bedeutung des Stanford-Potsdam Design Thinking-Ausbildungsmodells gut verstanden und dokumentiert ist, ist dies nicht der Fall, wenn es sich um nicht-westliche Kulturkreise handelt. Diese Arbeit schließt eine Lücke in der Literatur darüber, wie Design Thinking in der arabischen Welt entstanden ist, wahrgenommen, angenommen und praktiziert wurde. Die vorhandenen kulturellen Unterschiede zwischen der westlichen und der arabischen Welt wirken sich auch auf die Denkweise der Menschen aus, unddarauf, wie sie mit Design Thinking-Tools und -Methoden umgehen. Es wurde ein ‚Mixed Methods‘-Forschungsansatz verfolgt, d.h. sowohl quantitative als auch qualitative Methoden wurden eingesetzt. In der quantitativen Phase kamen zunächst zwei Methoden zum Einsatz: eine Social-Media-Analyse mit Twitter als Datenquelle und ein Online-Fragebogen. Die Ergebnisse und die Analyse der quantitativen Daten bildeten die Grundlage für die Gestaltung der qualitativen Phase, in der zwei Methoden angewendet wurden: zehn halbstrukturierte Interviews und die teilnehmende Beobachtung von sieben Design Thinking-Trainings. Den analysierten Daten zufolge scheint es in der arabischen Welt seit 2006 eine frühe, wenn auch relativ schwache und langsame Einführung von Design Thinking gegeben zu haben. In den letzten zehn Jahren ist jedoch eine zunehmende Akzeptanz zu beobachten, insbesondere in Saudi-Arabien, den Vereinigten Arabischen Emiraten und Ägypten. Die Ergebnisse zeigen auch, dass Design Thinking trotz seiner begrenzten Verbreitung am häufigsten im Bildungswesen, in der Informationstechnologie und Kommunikation, in der Verwaltung und im Non-Profit-Sektor angewandt wird. Die Art und Weise, wie Design Thinking praktiziert wird, stimmt jedoch nicht vollständig mit der Art und Weise überein, wie es in den USA und Europa praktiziert und gelehrt wird, da die meisten Menschen in der Region nicht unbedingt an alle Denkattribute glauben, die im Stanford-Potsdam-Modell eingeführt wurden. Die Praktiker in der arabischen Welt scheinen auch vor der "wilden Seite" des Design Thinking zurückzuschrecken und die Verbindung zwischen Kunst und Design auf der einen sowie Wissenschaft und Technik auf der anderen Seite nicht vollumfänglich zu schätzen. Dies wirft die Frage nach der Rolle von Bildungseinrichtungen in der Region auf, da sie - den Ergebnissen zufolge - die Bewegung zur Förderung und Entwicklung von Design Thinking in der arabischen Welt anzuführen scheinen. Nichtsdestotrotz ist es bemerkenswert, dass sich die Menschen der positiven Auswirkungen der Anwendung von Design Thinking in der Region und seines Potenzials, sinnvolle Veränderungen zu bewirken, bewusst zu sein scheinen. Sie scheinen jedoch auch besorgt zu sein über die aktuellen kulturellen, sozialen, politischen und wirtschaftlichen Herausforderungen, die diese Transformation in Frage stellen könnten. Daher fordern sie eine stärkere Sensibilisierung und die Schaffung von arabischen, kulturell angemessenen Programmen, um auf die lokalen Bedürfnisse einzugehen. Auch das Fehlen arabischer Inhalte und lokaler Fallstudien zu Design Thinking wurde von mehreren Befragten genannt und durch die teilnehmende Beobachtung bestätigt, da dies die Verbreitung von Design Thinking verlangsamt oder den Aufbau von Kapazitäten in der Region behindert. Weitere Herausforderungen, die sich aus der Studie ergaben, sind: die Veränderung des Mindsets der Menschen, das Fehlen spezieller Design-Thinking-Räume und der Bedarf an klaren Anweisungen zur Anwendung von Design-Thinking-Methoden und -Aktivitäten. Das Konzept von Zeit und der Umgang der arabischen Welt damit, Gender-Management während der Schulungen sowie Hierarchie und Machtdynamik unter den Schulungsteilnehmern gehören ebenfalls zu den identifizierten Herausforderungen. Ein weiteres wichtiges Ergebnis der Studie ist die Bestätigung von التفكير التصميمي als dem in der Region am weitesten verbreiteten arabischen Begriff für Design Thinking, da vier weitere arabische Begriffe mit Design Thinking in Verbindung gebracht werden konnten. Basierend auf den Ergebnissen der Studie schließt die Arbeit mit einer Liste von Empfehlungen, wie die genannten Herausforderungen überwunden werden können und welche Faktoren bei der Entwicklung und Implementierung von kulturell angepassten Design Thinking-Trainings in der arabischen Welt berücksichtigt werden sollten. KW - Design Thinking KW - human-centered design KW - the Arab world KW - emergence KW - adoption KW - implementation KW - culture KW - Design Thinking KW - Annahme KW - Kultur KW - Entstehung KW - menschenzentriertes Design KW - Implementierung KW - die arabische Welt Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-598911 ER -