@phdthesis{AlAreqi2017, author = {Al-Areqi, Samih Taha Mohammed}, title = {Semantics-based automatic geospatial service composition}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-402616}, school = {Universit{\"a}t Potsdam}, pages = {xvi, 163}, year = {2017}, abstract = {Although it has become common practice to build applications based on the reuse of existing components or services, technical complexity and semantic challenges constitute barriers to ensuring a successful and wide reuse of components and services. In the geospatial application domain, the barriers are self-evident due to heterogeneous geographic data, a lack of interoperability and complex analysis processes. Constructing workflows manually and discovering proper services and data that match user intents and preferences is difficult and time-consuming especially for users who are not trained in software development. Furthermore, considering the multi-objective nature of environmental modeling for the assessment of climate change impacts and the various types of geospatial data (e.g., formats, scales, and georeferencing systems) increases the complexity challenges. Automatic service composition approaches that provide semantics-based assistance in the process of workflow design have proven to be a solution to overcome these challenges and have become a frequent demand especially by end users who are not IT experts. In this light, the major contributions of this thesis are: (i) Simplification of service reuse and workflow design of applications for climate impact analysis by following the eXtreme Model-Driven Development (XMDD) paradigm. (ii) Design of a semantic domain model for climate impact analysis applications that comprises specifically designed services, ontologies that provide domain-specific vocabulary for referring to types and services, and the input/output annotation of the services using the terms defined in the ontologies. (iii) Application of a constraint-driven method for the automatic composition of workflows for analyzing the impacts of sea-level rise. The application scenario demonstrates the impact of domain modeling decisions on the results and the performance of the synthesis algorithm.}, language = {en} } @article{LindauerHoosLeytonBrownetal.2017, author = {Lindauer, Marius and Hoos, Holger and Leyton-Brown, Kevin and Schaub, Torsten}, title = {Automatic construction of parallel portfolios via algorithm configuration}, series = {Artificial intelligence}, volume = {244}, journal = {Artificial intelligence}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0004-3702}, doi = {10.1016/j.artint.2016.05.004}, pages = {272 -- 290}, year = {2017}, abstract = {Since 2004, increases in computational power described by Moore's law have substantially been realized in the form of additional cores rather than through faster clock speeds. To make effective use of modern hardware when solving hard computational problems, it is therefore necessary to employ parallel solution strategies. In this work, we demonstrate how effective parallel solvers for propositional satisfiability (SAT), one of the most widely studied NP-complete problems, can be produced automatically from any existing sequential, highly parametric SAT solver. Our Automatic Construction of Parallel Portfolios (ACPP) approach uses an automatic algorithm configuration procedure to identify a set of configurations that perform well when executed in parallel. Applied to two prominent SAT solvers, Lingeling and clasp, our ACPP procedure identified 8-core solvers that significantly outperformed their sequential counterparts on a diverse set of instances from the application and hard combinatorial category of the 2012 SAT Challenge. We further extended our ACPP approach to produce parallel portfolio solvers consisting of several different solvers by combining their configuration spaces. Applied to the component solvers of the 2012 SAT Challenge gold medal winning SAT Solver pfolioUZK, our ACPP procedures produced a significantly better-performing parallel SAT solver.}, language = {en} } @article{BaierDiCiccioMendlingetal.2018, author = {Baier, Thomas and Di Ciccio, Claudio and Mendling, Jan and Weske, Mathias}, title = {Matching events and activities by integrating behavioral aspects and label analysis}, series = {Software and systems modeling}, volume = {17}, journal = {Software and systems modeling}, number = {2}, publisher = {Springer}, address = {Heidelberg}, issn = {1619-1366}, doi = {10.1007/s10270-017-0603-z}, pages = {573 -- 598}, year = {2018}, abstract = {Nowadays, business processes are increasingly supported by IT services that produce massive amounts of event data during the execution of a process. These event data can be used to analyze the process using process mining techniques to discover the real process, measure conformance to a given process model, or to enhance existing models with performance information. Mapping the produced events to activities of a given process model is essential for conformance checking, annotation and understanding of process mining results. In order to accomplish this mapping with low manual effort, we developed a semi-automatic approach that maps events to activities using insights from behavioral analysis and label analysis. The approach extracts Declare constraints from both the log and the model to build matching constraints to efficiently reduce the number of possible mappings. These mappings are further reduced using techniques from natural language processing, which allow for a matching based on labels and external knowledge sources. The evaluation with synthetic and real-life data demonstrates the effectiveness of the approach and its robustness toward non-conforming execution logs.}, language = {en} } @article{PrzybyllaRomeike2018, author = {Przybylla, Mareen and Romeike, Ralf}, title = {Empowering learners with tools in CS education}, series = {it - Information Technology}, volume = {60}, journal = {it - Information Technology}, number = {2}, publisher = {De Gruyter}, address = {Berlin}, issn = {1611-2776}, doi = {10.1515/itit-2017-0032}, pages = {91 -- 101}, year = {2018}, abstract = {In computer science, computer systems are both, objects of investigation and tools that enable creative learning and design. Tools for learning have a long tradition in computer science education. Already in the late 1960s, Papert developed a concept which had an immense impact on the development of informal education in the following years: his theory of constructionism understands learning as a creative process of knowledge construction that is most effective when learners create something purposeful that they can try out, show around, discuss, analyse and receive praise for. By now, there are numerous learning and programming environments that are based on the constructionist ideas. Modern tools offer opportunities for students to learn in motivating ways and gain impressive results in programming games, animations, implementing 3D models or developing interactive objects. This article gives an overview of computer science education research related to tools and media to be used in educational settings. We analyse different types of tools with a special focus on the categorization and development of tools for student adequate physical computing activities in the classroom. Research around the development and evaluation of tools and learning resources in the domain of physical computing is illustrated with the example of "My Interactive Garden", a constructionist learning and programming environment. It is explained how the results from empirical studies are integrated in the continuous development of the learning material.}, language = {en} } @misc{FrankKreitz2018, author = {Frank, Mario and Kreitz, Christoph}, title = {A theorem prover for scientific and educational purposes}, series = {Electronic proceedings in theoretical computer science}, journal = {Electronic proceedings in theoretical computer science}, number = {267}, publisher = {Open Publishing Association}, address = {Sydney}, issn = {2075-2180}, doi = {10.4204/EPTCS.267.4}, pages = {59 -- 69}, year = {2018}, abstract = {We present a prototype of an integrated reasoning environment for educational purposes. The presented tool is a fragment of a proof assistant and automated theorem prover. We describe the existing and planned functionality of the theorem prover and especially the functionality of the educational fragment. This currently supports working with terms of the untyped lambda calculus and addresses both undergraduate students and researchers. We show how the tool can be used to support the students' understanding of functional programming and discuss general problems related to the process of building theorem proving software that aims at supporting both research and education.}, language = {en} } @incollection{KiyKnothMueller2018, author = {Kiy, Alexander and Knoth, Alexander Henning and M{\"u}ller, Ina}, title = {ReflectUP-App Situative und kontextbezogene Evaluation des Studieneinstiegs}, series = {Digitalisierung der Hochschullehre Neue Anforderungen an die Evaluation?}, booktitle = {Digitalisierung der Hochschullehre Neue Anforderungen an die Evaluation?}, editor = {Harris-Huemmert, Susan and Pohlenz, Philipp and Mitterauer, Lukas}, publisher = {Waxmann}, address = {M{\"u}nster}, isbn = {978-3-8309-3807-1}, publisher = {Universit{\"a}t Potsdam}, pages = {85 -- 102}, year = {2018}, language = {de} } @misc{BordihnNagyVaszil2018, author = {Bordihn, Henning and Nagy, Benedek and Vaszil, Gy{\"o}rgy}, title = {Preface: Non-classical models of automata and applications VIII}, series = {RAIRO-Theoretical informatics and appli and applications}, volume = {52}, journal = {RAIRO-Theoretical informatics and appli and applications}, number = {2-4}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0988-3754}, doi = {10.1051/ita/2018019}, pages = {87 -- 88}, year = {2018}, language = {en} } @misc{AfantenosPeldszusStede2018, author = {Afantenos, Stergos and Peldszus, Andreas and Stede, Manfred}, title = {Comparing decoding mechanisms for parsing argumentative structures}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1062}, issn = {1866-8372}, doi = {10.25932/publishup-47052}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-470527}, pages = {18}, year = {2018}, abstract = {Parsing of argumentative structures has become a very active line of research in recent years. Like discourse parsing or any other natural language task that requires prediction of linguistic structures, most approaches choose to learn a local model and then perform global decoding over the local probability distributions, often imposing constraints that are specific to the task at hand. Specifically for argumentation parsing, two decoding approaches have been recently proposed: Minimum Spanning Trees (MST) and Integer Linear Programming (ILP), following similar trends in discourse parsing. In contrast to discourse parsing though, where trees are not always used as underlying annotation schemes, argumentation structures so far have always been represented with trees. Using the 'argumentative microtext corpus' [in: Argumentation and Reasoned Action: Proceedings of the 1st European Conference on Argumentation, Lisbon 2015 / Vol. 2, College Publications, London, 2016, pp. 801-815] as underlying data and replicating three different decoding mechanisms, in this paper we propose a novel ILP decoder and an extension to our earlier MST work, and then thoroughly compare the approaches. The result is that our new decoder outperforms related work in important respects, and that in general, ILP and MST yield very similar performance.}, language = {en} } @article{PrescherBornscheinKoehlmannetal.2018, author = {Prescher, Denise and Bornschein, Jens and K{\"o}hlmann, Wiebke and Weber, Gerhard}, title = {Touching graphical applications}, series = {Universal Access in the Information Society}, volume = {17}, journal = {Universal Access in the Information Society}, number = {2}, publisher = {Springer}, address = {Heidelberg}, issn = {1615-5289}, doi = {10.1007/s10209-017-0538-8}, pages = {391 -- 409}, year = {2018}, abstract = {Novel two-dimensional tactile displays enable blind users to not only get access to the textual but also to the graphical content of a graphical user interface. Due to the higher amount of information that can be presented in parallel, orientation and exploration can be more complex. In this paper we present the HyperBraille system, which consists of a pin-matrix device as well as a graphical screen reader providing the user with appropriate presentation and interaction possibilities. To allow for a detailed analysis of bimanual interaction strategies on a pin-matrix device, we conducted two user studies with a total of 12 blind people. The task was to fill in .pdf forms on the pin-matrix device by using different input methods, namely gestures, built-in hardware buttons as well as a conventional PC keyboard. The forms were presented in a semigraphic view type that not only contains Braille but also tactile widgets in a spatial arrangement. While completion time and error rate partly depended on the chosen input method, the usage of special reading strategies seemed to be independent of it. A direct comparison of the system and a conventional assistive technology (screen reader with single-line Braille device) showed that interaction on the pin-matrix device can be very efficient if the user is trained. The two-dimensional output can improve access to .pdf forms with insufficient accessibility as the mapping of input controls and the corresponding labels can be supported by a spatial presentation.}, language = {en} } @article{AfantenosPeldszusStede2018, author = {Afantenos, Stergos and Peldszus, Andreas and Stede, Manfred}, title = {Comparing decoding mechanisms for parsing argumentative structures}, series = {Argument \& Computation}, volume = {9}, journal = {Argument \& Computation}, number = {3}, publisher = {IOS Press}, address = {Amsterdam}, issn = {1946-2166}, doi = {10.3233/AAC-180033}, pages = {177 -- 192}, year = {2018}, abstract = {Parsing of argumentative structures has become a very active line of research in recent years. Like discourse parsing or any other natural language task that requires prediction of linguistic structures, most approaches choose to learn a local model and then perform global decoding over the local probability distributions, often imposing constraints that are specific to the task at hand. Specifically for argumentation parsing, two decoding approaches have been recently proposed: Minimum Spanning Trees (MST) and Integer Linear Programming (ILP), following similar trends in discourse parsing. In contrast to discourse parsing though, where trees are not always used as underlying annotation schemes, argumentation structures so far have always been represented with trees. Using the 'argumentative microtext corpus' [in: Argumentation and Reasoned Action: Proceedings of the 1st European Conference on Argumentation, Lisbon 2015 / Vol. 2, College Publications, London, 2016, pp. 801-815] as underlying data and replicating three different decoding mechanisms, in this paper we propose a novel ILP decoder and an extension to our earlier MST work, and then thoroughly compare the approaches. The result is that our new decoder outperforms related work in important respects, and that in general, ILP and MST yield very similar performance.}, language = {en} } @misc{SahlmannSchwotzer2018, author = {Sahlmann, Kristina and Schwotzer, Thomas}, title = {Ontology-based virtual IoT devices for edge computing}, series = {Proceedings of the 8th International Conference on the Internet of Things}, journal = {Proceedings of the 8th International Conference on the Internet of Things}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-6564-2}, doi = {10.1145/3277593.3277597}, pages = {1 -- 7}, year = {2018}, abstract = {An IoT network may consist of hundreds heterogeneous devices. Some of them may be constrained in terms of memory, power, processing and network capacity. Manual network and service management of IoT devices are challenging. We propose a usage of an ontology for the IoT device descriptions enabling automatic network management as well as service discovery and aggregation. Our IoT architecture approach ensures interoperability using existing standards, i.e. MQTT protocol and SemanticWeb technologies. We herein introduce virtual IoT devices and their semantic framework deployed at the edge of network. As a result, virtual devices are enabled to aggregate capabilities of IoT devices, derive new services by inference, delegate requests/responses and generate events. Furthermore, they can collect and pre-process sensor data. These tasks on the edge computing overcome the shortcomings of the cloud usage regarding siloization, network bandwidth, latency and speed. We validate our proposition by implementing a virtual device on a Raspberry Pi.}, language = {en} } @misc{BoehneKreitz2018, author = {B{\"o}hne, Sebastian and Kreitz, Christoph}, title = {Learning how to prove}, series = {Electronic proceedings in theoretical computer science}, journal = {Electronic proceedings in theoretical computer science}, number = {267}, publisher = {Open Publishing Association}, address = {Sydney}, issn = {2075-2180}, doi = {10.4204/EPTCS.267.1}, pages = {1 -- 18}, year = {2018}, abstract = {We have developed an alternative approach to teaching computer science students how to prove. First, students are taught how to prove theorems with the Coq proof assistant. In a second, more difficult, step students will transfer their acquired skills to the area of textbook proofs. In this article we present a realisation of the second step. Proofs in Coq have a high degree of formality while textbook proofs have only a medium one. Therefore our key idea is to reduce the degree of formality from the level of Coq to textbook proofs in several small steps. For that purpose we introduce three proof styles between Coq and textbook proofs, called line by line comments, weakened line by line comments, and structure faithful proofs. While this article is mostly conceptional we also report on experiences with putting our approach into practise.}, language = {en} } @article{GianniniRichterServettoetal.2018, author = {Giannini, Paola and Richter, Tim and Servetto, Marco and Zucca, Elena}, title = {Tracing sharing in an imperative pure calculus}, series = {Science of computer programming}, volume = {172}, journal = {Science of computer programming}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0167-6423}, doi = {10.1016/j.scico.2018.11.007}, pages = {180 -- 202}, year = {2018}, abstract = {We introduce a type and effect system, for an imperative object calculus, which infers sharing possibly introduced by the evaluation of an expression, represented as an equivalence relation among its free variables. This direct representation of sharing effects at the syntactic level allows us to express in a natural way, and to generalize, widely-used notions in literature, notably uniqueness and borrowing. Moreover, the calculus is pure in the sense that reduction is defined on language terms only, since they directly encode store. The advantage of this non-standard execution model with respect to a behaviorally equivalent standard model using a global auxiliary structure is that reachability relations among references are partly encoded by scoping. (C) 2018 Elsevier B.V. All rights reserved.}, language = {en} } @incollection{KiyLucke2018, author = {Kiy, Alexander and Lucke, Ulrike}, title = {Mobile Unterst{\"u}tzung im Studienalltag zwischen Generalit{\"a}t und Individualit{\"a}t}, series = {Handbuch Mobile Learning}, volume = {2018}, booktitle = {Handbuch Mobile Learning}, editor = {de Witt, Claudia and Gloerfeld, Christina}, publisher = {Springer VS}, address = {Wiesbaden}, isbn = {978-3-658-19123-8}, doi = {10.1007/978-3-658-19123-8_37}, publisher = {Universit{\"a}t Potsdam}, pages = {777 -- 808}, year = {2018}, abstract = {Mobile Endger{\"a}te und Applikationen (Apps) sind dank vielf{\"a}ltiger Kommunikations-, Informations- und Assistenzfunktionen zu einem unverzichtbaren Bestandteil unseres t{\"a}glichen Lebens geworden. Inzwischen hat sich insbesondere im Hochschulumfeld eine bunte Vielfalt an mobilen Unterst{\"u}tzungsangeboten etabliert, beginnend bei zentral angebotenen Uni-Apps bis hin zu unterschiedlichen Apps zur Ausgestaltung einzelner Lehrveranstaltungen oder individueller Lehr- und Lernszenarien. Angesichts der großen Aufw{\"a}nde zur Entwicklung, Distribution und Pflege mobiler Anwendungen ist ein Einsatz f{\"u}r eine m{\"o}glichst große Zielgruppe w{\"u}nschenswert. Dies kann jedoch mit dem Charakter mobiler Endger{\"a}te als pers{\"o}nliche, individualisierte Assistenten kollidieren. In diesem Beitrag werden entlang dieses Spektrums zwischen (fach-)spezifischen Einzell{\"o}sungen und breiten Allroundern verschiedene mobile Unterst{\"u}tzungsangebote aus dem Hochschulbereich vorgestellt, hinsichtlich ihres Einsatzes kontextuell eingeordnet und systematisiert. Dies umfasst mobile Anwendungen, die allgemeine organisatorische Aspekte des Studiums, bestimmte Felder wie die Studieneingangsphase oder die konkrete Begleitung hybrider Lernszenarien fokussieren. Es schließt sich eine App-Auswahl an, die fachspezifischen Aspekten Rechnung tr{\"a}gt und in denen Inhalte in Form von Serious Games, Simulationen und Inhaltsmodulen aufbereitet sind. Neben Lehre und Studium wird auch die Forschung in den Fokus ger{\"u}ckt, wo Apps gleichermaßen als Forschungsgegenstand und Datenerhebungsinstrument wirken. Aus der F{\"u}lle dieser Entwicklungen resultiert eine App-Vielfalt, die verschiedene Herausforderungen aufwirft. Der Beitrag stellt die spezifischen Herausforderungen zusammen und spricht Empfehlungen aus. Dabei werden sowohl organisatorische, inhaltliche und technische Fragestellungen thematisiert als auch rechtliche Gesichtspunkte bez{\"u}glich Datenschutz und Copyright tangiert.}, language = {de} } @phdthesis{Feinbube2018, author = {Feinbube, Frank}, title = {Ans{\"a}tze zur Integration von Beschleunigern ins Betriebssystem}, school = {Universit{\"a}t Potsdam}, pages = {238}, year = {2018}, language = {de} } @article{BordihnMitranaNegruetal.2018, author = {Bordihn, Henning and Mitrana, Victor and Negru, Maria C. and Paun, Andrei and Paun, Mihaela}, title = {Small networks of polarized splicing processors are universal}, series = {Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal}, volume = {17}, journal = {Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal}, number = {4}, publisher = {Springer}, address = {Dordrecht}, issn = {1567-7818}, doi = {10.1007/s11047-018-9691-0}, pages = {799 -- 809}, year = {2018}, abstract = {In this paper, we consider the computational power of a new variant of networks of splicing processors in which each processor as well as the data navigating throughout the network are now considered to be polarized. While the polarization of every processor is predefined (negative, neutral, positive), the polarization of data is dynamically computed by means of a valuation mapping. Consequently, the protocol of communication is naturally defined by means of this polarization. We show that networks of polarized splicing processors (NPSP) of size 2 are computationally complete, which immediately settles the question of designing computationally complete NPSPs of minimal size. With two more nodes we can simulate every nondeterministic Turing machine without increasing the time complexity. Particularly, we prove that NPSP of size 4 can accept all languages in NP in polynomial time. Furthermore, another computational model that is universal, namely the 2-tag system, can be simulated by NPSP of size 3 preserving the time complexity. All these results can be obtained with NPSPs with valuations in the set as well. We finally show that Turing machines can simulate a variant of NPSPs and discuss the time complexity of this simulation.}, language = {en} } @article{TscherejkinaMorgielMoebert2018, author = {Tscherejkina, Anna and Morgiel, Anna and Moebert, Tobias}, title = {Computergest{\"u}tztes Training von sozio-emotionalen Kompetenzen durch Minispiele}, series = {E-Learning Symposium 2018}, journal = {E-Learning Symposium 2018}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, doi = {10.25932/publishup-42193}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-421937}, pages = {41 -- 52}, year = {2018}, abstract = {Das Training sozioemotionaler Kompetenzen ist gerade f{\"u}r Menschen mit Autismus n{\"u}tzlich. Ein solches Training kann mithilfe einer spielbasierten Anwendung effektiv gestaltet werden. Zwei Minispiele, Mimikry und Emo-Mahjong, wurden realisiert und hinsichtlich User Experience evaluiert. Die jeweiligen Konzepte und die Evaluationsergebnisse sollen hier vorgestellt werden.}, language = {de} } @phdthesis{Przybylla2018, author = {Przybylla, Mareen}, title = {From Embedded Systems to Physical Computing: Challenges of the "Digital World" in Secondary Computer Science Education}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418339}, school = {Universit{\"a}t Potsdam}, pages = {xvii, 277}, year = {2018}, abstract = {Physical computing covers the design and realization of interactive objects and installations and allows learners to develop concrete, tangible products of the real world, which arise from their imagination. This can be used in computer science education to provide learners with interesting and motivating access to the different topic areas of the subject in constructionist and creative learning environments. However, if at all, physical computing has so far mostly been taught in afternoon clubs or other extracurricular settings. Thus, for the majority of students so far there are no opportunities to design and create their own interactive objects in regular school lessons. Despite its increasing popularity also for schools, the topic has not yet been clearly and sufficiently characterized in the context of computer science education. The aim of this doctoral thesis therefore is to clarify physical computing from the perspective of computer science education and to adequately prepare the topic both content-wise and methodologically for secondary school teaching. For this purpose, teaching examples, activities, materials and guidelines for classroom use are developed, implemented and evaluated in schools. In the theoretical part of the thesis, first the topic is examined from a technical point of view. A structured literature analysis shows that basic concepts used in physical computing can be derived from embedded systems, which are the core of a large field of different application areas and disciplines. Typical methods of physical computing in professional settings are analyzed and, from an educational perspective, elements suitable for computer science teaching in secondary schools are extracted, e. g. tinkering and prototyping. The investigation and classification of suitable tools for school teaching show that microcontrollers and mini computers, often with extensions that greatly facilitate the handling of additional components, are particularly attractive tools for secondary education. Considering the perspectives of science, teachers, students and society, in addition to general design principles, exemplary teaching approaches for school education and suitable learning materials are developed and the design, production and evaluation of a physical computing construction kit suitable for teaching is described. In the practical part of this thesis, with "My Interactive Garden", an exemplary approach to integrate physical computing in computer science teaching is tested and evaluated in different courses and refined based on the findings in a design-based research approach. In a series of workshops on physical computing, which is based on a concept for constructionist professional development that is developed specifically for this purpose, teachers are empowered and encouraged to develop and conduct physical computing lessons suitable for their particular classroom settings. Based on their in-class experiences, a process model of physical computing teaching is derived. Interviews with those teachers illustrate that benefits of physical computing, including the tangibility of crafted objects and creativity in the classroom, outweigh possible drawbacks like longer preparation times, technical difficulties or difficult assessment. Hurdles in the classroom are identified and possible solutions discussed. Empirical investigations in the different settings reveal that "My Interactive Garden" and physical computing in general have a positive impact, among others, on learner motivation, fun and interest in class and perceived competencies. Finally, the results from all evaluations are combined to evaluate the design principles for physical computing teaching and to provide a perspective on the development of decision-making aids for physical computing activities in school education.}, language = {en} } @article{Kiy2018, author = {Kiy, Alexander}, title = {Digitale Medien \& Hochschul-Cloud: Eine vielversprechende Verbindung}, series = {eleed}, journal = {eleed}, number = {12}, year = {2018}, abstract = {Ob Online-Kurse, videobasierte Lehrangebote, mobile Applikationen, eigenentwickelte oder kommerzielle Web 2.0-Anwendungen, die F{\"u}lle digitaler Unterst{\"u}tzungsangebote ist kaum zu {\"u}berblicken. Dabei bieten mobile Endger{\"a}te, Web-Anwendungen und Apps Chancen Lehre, Studium und Forschung maßgeblich neu zu gestalten. Im Beitrag wird ein Beschreibungsrahmen f{\"u}r die mediendidaktische Ausgestaltung von Lehr-, Lern- und Forschungsarrangements vorgestellt, der die technischen Gesichtspunkte hervorhebt. Anschließend werden unterschiedliche Nutzungsszenarien unter Einbeziehung digitaler Medien skizziert. Diese werden als Ausgangspunkt genommen um das Konzept einer Systemarchitektur vorzustellen, die es zum einen erm{\"o}glicht beliebige Applikationen automatisiert bereit zu stellen und zum anderen die anfallenden Nutzendendaten plattform{\"u}bergreifend zu aggregieren und f{\"u}r eine Ausgestaltung virtueller Lehr- und Lernr{\"a}umen zu nutzen.}, language = {de} } @misc{MarweckiBaudisch2018, author = {Marwecki, Sebastian and Baudisch, Patrick}, title = {Scenograph}, series = {UIST '18: Proceedings of the 31st Annual ACM Symposium on User Interface Software and Technology}, journal = {UIST '18: Proceedings of the 31st Annual ACM Symposium on User Interface Software and Technology}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-5948-1}, doi = {10.1145/3242587.3242648}, pages = {511 -- 520}, year = {2018}, abstract = {When developing a real-walking virtual reality experience, designers generally create virtual locations to fit a specific tracking volume. Unfortunately, this prevents the resulting experience from running on a smaller or differently shaped tracking volume. To address this, we present a software system called Scenograph. The core of Scenograph is a tracking volume-independent representation of real-walking experiences. Scenograph instantiates the experience to a tracking volume of given size and shape by splitting the locations into smaller ones while maintaining narrative structure. In our user study, participants' ratings of realism decreased significantly when existing techniques were used to map a 25m2 experience to 9m2 and an L-shaped 8m2 tracking volume. In contrast, ratings did not differ when Scenograph was used to instantiate the experience.}, language = {en} } @misc{KliemeTietzMeinel2018, author = {Klieme, Eric and Tietz, Christian and Meinel, Christoph}, title = {Beware of SMOMBIES}, series = {The 17th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (IEEE TrustCom 2018)/the 12th IEEE International Conference on Big Data Science and Engineering (IEEE BigDataSE 2018)}, journal = {The 17th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (IEEE TrustCom 2018)/the 12th IEEE International Conference on Big Data Science and Engineering (IEEE BigDataSE 2018)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-4387-7}, issn = {2324-9013}, doi = {10.1109/TrustCom/BigDataSE.2018.00096}, pages = {651 -- 660}, year = {2018}, abstract = {Several research evaluated the user's style of walking for the verification of a claimed identity and showed high authentication accuracies in many settings. In this paper we present a system that successfully verifies a user's identity based on many real world smartphone placements and yet not regarded interactions while walking. Our contribution is the distinction of all considered activities into three distinct subsets and a specific one-class Support Vector Machine per subset. Using sensor data of 30 participants collected in a semi-supervised study approach, we prove that unsupervised verification is possible with very low false-acceptance and false-rejection rates. We furthermore show that these subsets can be distinguished with a high accuracy and demonstrate that this system can be deployed on off-the-shelf smartphones.}, language = {en} } @inproceedings{KeilKonertDamniketal.2018, author = {Keil, Reinhard and Konert, Johannes and Damnik, Gregor and Gierl, Mark J. and Proske, Antje and K{\"o}rndle, Hermann and Narciss, Susanne and Wahl, Marina and H{\"o}lscher, Michael and Mariani, Ennio and Jaisli, Isabel and Tscherejkina, Anna and Morgiel, Anna and Moebert, Tobias and Herbstreit, Stephanie and M{\"a}ker, Daniela and Szalai, Cynthia and Braun, Iris and Kapp, Felix and Hara, Tenshi C. and Kubica, Tommy and Stumpf, Sarah}, title = {E-Learning Symposium 2018}, editor = {Lucke, Ulrike and Strickroth, Sven}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, doi = {10.25932/publishup-42071}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-420711}, pages = {71}, year = {2018}, abstract = {In den vergangenen Jahren sind viele E-Learning-Innovationen entstanden. Einige davon wurden auf den vergangenen E-Learning Symposien der Universit{\"a}t Potsdam pr{\"a}sentiert: Das erste E-Learning Symposium im Jahr 2012 konzentrierte sich auf unterschiedliche M{\"o}glichkeiten der Studierendenaktivierung und Lehrgestaltung. Das Symposium 2014 r{\"u}ckte vor allem die Studierenden ins Zentrum der Aufmerksamkeit. Im Jahr 2016 kam es durch das Zusammengehen des Symposiums mit der DeLFI-Tagung zu einer Fokussierung auf technische Innovationen. Doch was ist aus den Leuchtt{\"u}rmen von gestern geworden, und brauchen wir {\"u}berhaupt noch neue Leuchtt{\"u}rme? Das Symposium setzt sich in diesem Jahr unter dem Motto „Innovation und Nachhaltigkeit - (k)ein Gegensatz?" mit mediengest{\"u}tzten Lehr- und Lernprozessen im universit{\"a}ren Kontext auseinander und reflektiert aktuelle technische sowie didaktische Entwicklungen mit Blick auf deren mittel- bis langfristigen Einsatz in der Praxis. Dieser Tagungsband zum E-Learning Symposium 2018 an der Universit{\"a}t Potsdam beinhaltet eine Mischung von Forschungs- und Praxisbeitr{\"a}gen aus verschiedenen Fachdisziplinen und er{\"o}ffnet vielschichtige Perspektiven auf das Thema E-Learning. Dabei werden die Vielfalt der didaktischen Einsatzszenarien als auch die Potentiale von Werk-zeugen und Methoden der Informatik in ihrem Zusammenspiel beleuchtet. In seiner Keynote widmet sich Reinhard Keil dem Motto des Symposiums und geht der Nachhaltigkeit bei E-Learning-Projekten auf den Grund. Dabei analysiert und beleuchtet er anhand seiner {\"u}ber 15-j{\"a}hrigen Forschungspraxis die wichtigsten Wirkfaktoren und formuliert Empfehlungen zur Konzeption von E-Learning-Projekten. Im Gegensatz zu rein auf Kostenersparnis ausgerichteten (hochschul-)politischen Forderungen proklamiert er den Ansatz der hypothesengeleiteten Technikgestaltung, in der Nachhaltigkeit als Leitfrage oder Forschungsstrategie verstanden werden kann. In eine {\"a}hnliche Richtung geht der Beitrag von Iris Braun et al., die {\"u}ber Erfolgsfaktoren beim Einsatz von Audience Response Systemen in der universit{\"a}ren Lehre berichten. Ein weiteres aktuelles Thema, sowohl f{\"u}r die Bildungstechnologie als auch in den Bildungswissenschaften allgemein, ist die Kompetenzorientierung und -modellierung. Hier geht es darum (Probleml{\"o}se-)F{\"a}higkeiten gezielt zu beschreiben und in den Mittelpunkt der Lehre zu stellen. Johannes Konert stellt in einem eingeladenen Vortrag zwei Projekte vor, die den Prozess beginnend bei der Definition von Kompetenzen, deren Modellierung in einem semantischen maschinenlesbaren Format bis hin zur Erarbeitung von Methoden zur Kompetenzmessung und der elektronischen Zertifizierung aufzeigen. Dabei geht er auf technische M{\"o}glichkeiten, aber auch Grenzen ein. Auf einer spezifischeren Ebene besch{\"a}ftigt sich Sarah Stumpf mit digitalen bzw. mediendidaktischen Kompetenzen im Lehramtsstudium und stellt ein Framework f{\"u}r die F{\"o}rderung ebensolcher Kompetenzen bei angehenden Lehrkr{\"a}ften vor. Der Einsatz von E-Learning birgt noch einige Herausforderungen. Dabei geht es oft um die Verbindung von Didaktik und Technik, den Erhalt von Aufmerksamkeit oder den Aufwand f{\"u}r das Erstellen von interaktiven Lehr- und Lerninhalten. Drei Beitr{\"a}ge in diesem Tagungsband besch{\"a}ftigen sich mit dieser Thematik in unterschiedlichen Kontexten und zeigen Best-Practices und L{\"o}sungsans{\"a}tze auf: Der Beitrag von Martina Wahl und Michael H{\"o}lscher behandelt den besonderen Kontext von Blended Learning-Szenarien in berufsbegleitenden Studieng{\"a}ngen. Um die Ver{\"o}ffentlichung eines global frei verf{\"u}gbaren Onlinekurses abseits der großen MOOC Plattformen und den didaktischen Herausforderungen auch hinsichtlich der Motivation geht es im Beitrag von Ennio Marani und Isabel Jaisli. Schließlich schlagen Gregor Damnik et al. die automatische Erzeugung von Aufgaben zur Erh{\"o}hung von Interaktivit{\"a}t und Adaptivit{\"a}t in digitalen Lernressourcen vor, um den teilweise erheblichen Erstellungsaufwand zu reduzieren. Zum Thema E-Learning z{\"a}hlen auch immer mobile Apps bzw. Spiele. Gleich zwei Beitr{\"a}ge besch{\"a}ftigen sich mit dem Einsatz von E-Learning-Tools im Gesundheitskontext: Anna Tscherejkina und Anna Morgiel stellen in ihrem Beitrag Minispiele zum Training von sozio-emotionalen Kompetenzen f{\"u}r Menschen mit Autismus vor, und Stephanie Herbstreit et al. berichten vom Einsatz einer mobilen Lern-App zur Verbesserung von klinisch-praktischem Unterricht.}, language = {de} } @inproceedings{SeegererRomeikeTillmannetal.2018, author = {Seegerer, Stefan and Romeike, Ralf and Tillmann, Alexander and Kr{\"o}mker, Detlef and Horn, Florian and Gattinger, Thorsten and Weicker, Karsten and Schmitz, Dennis and Moldt, Daniel and R{\"o}pke, Ren{\´e} and Larisch, Kathrin and Schroeder, Ulrik and Keverp{\"u}tz, Claudia and K{\"u}ppers, Bastian and Striewe, Michael and Kramer, Matthias and Grillenberger, Andreas and Frede, Christiane and Knobelsdorf, Maria and Greven, Christoph}, title = {Hochschuldidaktik der Informatik HDI 2018}, series = {Commentarii informaticae didacticae (CID)}, booktitle = {Commentarii informaticae didacticae (CID)}, number = {12}, editor = {Bergner, Nadine and R{\"o}pke, Ren{\´e} and Schroeder, Ulrik and Kr{\"o}mker, Detlef}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-435-7}, issn = {1868-0844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-413542}, pages = {161}, year = {2018}, abstract = {Die 8. Fachtagung f{\"u}r Hochschuldidaktik der Informatik (HDI) fand im September 2018 zusammen mit der Deutschen E-Learning Fachtagung Informatik (DeLFI) unter dem gemeinsamen Motto „Digitalisierungswahnsinn? - Wege der Bildungstransformationen" in Frankfurt statt. Dabei widmet sich die HDI allen Fragen der informatischen Bildung im Hochschulbereich. Schwerpunkte bildeten in diesem Jahr u. a.: - Analyse der Inhalte und anzustrebenden Kompetenzen in Informatikveranstaltungen - Programmieren lernen \& Einstieg in Softwareentwicklung - Spezialthemen: Data Science, Theoretische Informatik und Wissenschaftliches Arbeiten Die Fachtagung widmet sich ausgew{\"a}hlten Fragestellungen dieser Themenkomplexe, die durch Vortr{\"a}ge ausgewiesener Experten und durch eingereichte Beitr{\"a}ge intensiv behandelt werden.}, language = {de} } @article{LiChenNofaletal.2018, author = {Li, Yuanqing and Chen, Li and Nofal, Issam and Chen, Mo and Wang, Haibin and Liu, Rui and Chen, Qingyu and Krstić, Miloš and Shi, Shuting and Guo, Gang and Baeg, Sang H. and Wen, Shi-Jie and Wong, Richard}, title = {Modeling and analysis of single-event transient sensitivity of a 65 nm clock tree}, series = {Microelectronics reliability}, volume = {87}, journal = {Microelectronics reliability}, publisher = {Elsevier}, address = {Oxford}, issn = {0026-2714}, doi = {10.1016/j.microrel.2018.05.016}, pages = {24 -- 32}, year = {2018}, abstract = {The soft error rate (SER) due to heavy-ion irradiation of a clock tree is investigated in this paper. A method for clock tree SER prediction is developed, which employs a dedicated soft error analysis tool to characterize the single-event transient (SET) sensitivities of clock inverters and other commercial tools to calculate the SER through fault-injection simulations. A test circuit including a flip-flop chain and clock tree in a 65 nm CMOS technology is developed through the automatic ASIC design flow. This circuit is analyzed with the developed method to calculate its clock tree SER. In addition, this circuit is implemented in a 65 nm test chip and irradiated by heavy ions to measure its SER resulting from the SETs in the clock tree. The experimental and calculation results of this case study present good correlation, which verifies the effectiveness of the developed method.}, language = {en} } @misc{KrstićJentzsch2018, author = {Krstić, Miloš and Jentzsch, Anne-Kristin}, title = {Reliability, safety and security of the electronics in automated driving vehicles - joint lab lecturing approach}, series = {2018 12TH European Workshop on Microelectronics Education (EWME)}, journal = {2018 12TH European Workshop on Microelectronics Education (EWME)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-1157-9}, pages = {21 -- 22}, year = {2018}, abstract = {This paper proposes an education approach for master and bachelor students to enhance their skills in the area of reliability, safety and security of the electronic components in automated driving. The approach is based on the active synergetic work of research institutes, academia and industry in the frame of joint lab. As an example, the jointly organized summer school with the respective focus is organized and elaborated.}, language = {en} } @article{BrewkaEllmauthalerKernIsberneretal.2018, author = {Brewka, Gerhard and Ellmauthaler, Stefan and Kern-Isberner, Gabriele and Obermeier, Philipp and Ostrowski, Max and Romero, Javier and Schaub, Torsten and Schieweck, Steffen}, title = {Advanced solving technology for dynamic and reactive applications}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0538-8}, pages = {199 -- 200}, year = {2018}, language = {en} } @article{SchaubWoltran2018, author = {Schaub, Torsten and Woltran, Stefan}, title = {Answer set programming unleashed!}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0550-z}, pages = {105 -- 108}, year = {2018}, abstract = {Answer Set Programming faces an increasing popularity for problem solving in various domains. While its modeling language allows us to express many complex problems in an easy way, its solving technology enables their effective resolution. In what follows, we detail some of the key factors of its success. Answer Set Programming [ASP; Brewka et al. Commun ACM 54(12):92-103, (2011)] is seeing a rapid proliferation in academia and industry due to its easy and flexible way to model and solve knowledge-intense combinatorial (optimization) problems. To this end, ASP offers a high-level modeling language paired with high-performance solving technology. As a result, ASP systems provide out-off-the-box, general-purpose search engines that allow for enumerating (optimal) solutions. They are represented as answer sets, each being a set of atoms representing a solution. The declarative approach of ASP allows a user to concentrate on a problem's specification rather than the computational means to solve it. This makes ASP a prime candidate for rapid prototyping and an attractive tool for teaching key AI techniques since complex problems can be expressed in a succinct and elaboration tolerant way. This is eased by the tuning of ASP's modeling language to knowledge representation and reasoning (KRR). The resulting impact is nicely reflected by a growing range of successful applications of ASP [Erdem et al. AI Mag 37(3):53-68, 2016; Falkner et al. Industrial applications of answer set programming. K++nstliche Intelligenz (2018)]}, language = {en} } @misc{BrewkaSchaubWoltran2018, author = {Brewka, Gerhard and Schaub, Torsten and Woltran, Stefan}, title = {Interview with Gerhard Brewka}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0549-5}, pages = {219 -- 221}, year = {2018}, abstract = {This interview with Gerhard Brewka was conducted by correspondance in May 2018. The question set was compiled by Torsten Schaub and Stefan Woltran.}, language = {en} } @misc{SchaubWoltran2018, author = {Schaub, Torsten and Woltran, Stefan}, title = {Special issue on answer set programming}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0554-8}, pages = {101 -- 103}, year = {2018}, language = {en} } @misc{SchaepersNiemuellerLakemeyeretal.2018, author = {Sch{\"a}pers, Bj{\"o}rn and Niemueller, Tim and Lakemeyer, Gerhard and Gebser, Martin and Schaub, Torsten}, title = {ASP-Based Time-Bounded Planning for Logistics Robots}, series = {Twenty-Eighth International Conference on Automated Planning and Scheduling (ICAPS 2018)}, journal = {Twenty-Eighth International Conference on Automated Planning and Scheduling (ICAPS 2018)}, publisher = {ASSOC Association for the Advancement of Artificial Intelligence}, address = {Palo Alto}, issn = {2334-0835}, pages = {509 -- 517}, year = {2018}, abstract = {Manufacturing industries are undergoing a major paradigm shift towards more autonomy. Automated planning and scheduling then becomes a necessity. The Planning and Execution Competition for Logistics Robots in Simulation held at ICAPS is based on this scenario and provides an interesting testbed. However, the posed problem is challenging as also demonstrated by the somewhat weak results in 2017. The domain requires temporal reasoning and dealing with uncertainty. We propose a novel planning system based on Answer Set Programming and the Clingo solver to tackle these problems and incentivize robot cooperation. Our results show a significant performance improvement, both, in terms of lowering computational requirements and better game metrics.}, language = {en} } @misc{BosserCabalarDieguezetal.2018, author = {Bosser, Anne-Gwenn and Cabalar, Pedro and Dieguez, Martin and Schaub, Torsten}, title = {Introducing temporal stable models for linear dynamic logic}, series = {16th International Conference on Principles of Knowledge Representation and Reasoning}, journal = {16th International Conference on Principles of Knowledge Representation and Reasoning}, publisher = {ASSOC Association for the Advancement of Artificial Intelligence}, address = {Palo Alto}, pages = {12 -- 21}, year = {2018}, abstract = {We propose a new temporal extension of the logic of Here-and-There (HT) and its equilibria obtained by combining it with dynamic logic over (linear) traces. Unlike previous temporal extensions of HT based on linear temporal logic, the dynamic logic features allow us to reason about the composition of actions. For instance, this can be used to exercise fine grained control when planning in robotics, as exemplified by GOLOG. In this paper, we lay the foundations of our approach, and refer to it as Linear Dynamic Equilibrium Logic, or simply DEL. We start by developing the formal framework of DEL and provide relevant characteristic results. Among them, we elaborate upon the relationships to traditional linear dynamic logic and previous temporal extensions of HT.}, language = {en} } @phdthesis{Ostrowski2018, author = {Ostrowski, Max}, title = {Modern constraint answer set solving}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407799}, school = {Universit{\"a}t Potsdam}, pages = {135}, year = {2018}, abstract = {Answer Set Programming (ASP) is a declarative problem solving approach, combining a rich yet simple modeling language with high-performance solving capabilities. Although this has already resulted in various applications, certain aspects of such applications are more naturally modeled using variables over finite domains, for accounting for resources, fine timings, coordinates, or functions. Our goal is thus to extend ASP with constraints over integers while preserving its declarative nature. This allows for fast prototyping and elaboration tolerant problem descriptions of resource related applications. The resulting paradigm is called Constraint Answer Set Programming (CASP). We present three different approaches for solving CASP problems. The first one, a lazy, modular approach combines an ASP solver with an external system for handling constraints. This approach has the advantage that two state of the art technologies work hand in hand to solve the problem, each concentrating on its part of the problem. The drawback is that inter-constraint dependencies cannot be communicated back to the ASP solver, impeding its learning algorithm. The second approach translates all constraints to ASP. Using the appropriate encoding techniques, this results in a very fast, monolithic system. Unfortunately, due to the large, explicit representation of constraints and variables, translation techniques are restricted to small and mid-sized domains. The third approach merges the lazy and the translational approach, combining the strength of both while removing their weaknesses. To this end, we enhance the dedicated learning techniques of an ASP solver with the inferences of the translating approach in a lazy way. That is, the important knowledge is only made explicit when needed. By using state of the art techniques from neighboring fields, we provide ways to tackle real world, industrial size problems. By extending CASP to reactive solving, we open up new application areas such as online planning with continuous domains and durations.}, language = {en} } @article{GebserObermeierSchaubetal.2018, author = {Gebser, Martin and Obermeier, Philipp and Schaub, Torsten and Ratsch-Heitmann, Michel and Runge, Mario}, title = {Routing driverless transport vehicles in car assembly with answer set programming}, series = {Theory and practice of logic programming}, volume = {18}, journal = {Theory and practice of logic programming}, number = {3-4}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068418000182}, pages = {520 -- 534}, year = {2018}, abstract = {Automated storage and retrieval systems are principal components of modern production and warehouse facilities. In particular, automated guided vehicles nowadays substitute human-operated pallet trucks in transporting production materials between storage locations and assembly stations. While low-level control systems take care of navigating such driverless vehicles along programmed routes and avoid collisions even under unforeseen circumstances, in the common case of multiple vehicles sharing the same operation area, the problem remains how to set up routes such that a collection of transport tasks is accomplished most effectively. We address this prevalent problem in the context of car assembly at Mercedes-Benz Ludwigsfelde GmbH, a large-scale producer of commercial vehicles, where routes for automated guided vehicles used in the production process have traditionally been hand-coded by human engineers. Such adhoc methods may suffice as long as a running production process remains in place, while any change in the factory layout or production targets necessitates tedious manual reconfiguration, not to mention the missing portability between different production plants. Unlike this, we propose a declarative approach based on Answer Set Programming to optimize the routes taken by automated guided vehicles for accomplishing transport tasks. The advantages include a transparent and executable problem formalization, provable optimality of routes relative to objective criteria, as well as elaboration tolerance towards particular factory layouts and production targets. Moreover, we demonstrate that our approach is efficient enough to deal with the transport tasks evolving in realistic production processes at the car factory of Mercedes-Benz Ludwigsfelde GmbH.}, language = {en} } @misc{LifschitzSchaubWoltran2018, author = {Lifschitz, Vladimir and Schaub, Torsten and Woltran, Stefan}, title = {Interview with Vladimir Lifschitz}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0552-x}, pages = {213 -- 218}, year = {2018}, abstract = {This interview with Vladimir Lifschitz was conducted by Torsten Schaub at the University of Texas at Austin in August 2017. The question set was compiled by Torsten Schaub and Stefan Woltran.}, language = {en} } @article{BanbaraInoueKaufmannetal.2018, author = {Banbara, Mutsunori and Inoue, Katsumi and Kaufmann, Benjamin and Okimoto, Tenda and Schaub, Torsten and Soh, Takehide and Tamura, Naoyuki and Wanko, Philipp}, title = {teaspoon}, series = {Annals of operation research}, volume = {275}, journal = {Annals of operation research}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {0254-5330}, doi = {10.1007/s10479-018-2757-7}, pages = {3 -- 37}, year = {2018}, abstract = {Answer Set Programming (ASP) is an approach to declarative problem solving, combining a rich yet simple modeling language with high performance solving capacities. We here develop an ASP-based approach to curriculum-based course timetabling (CB-CTT), one of the most widely studied course timetabling problems. The resulting teaspoon system reads a CB-CTT instance of a standard input format and converts it into a set of ASP facts. In turn, these facts are combined with a first-order encoding for CB-CTT solving, which can subsequently be solved by any off-the-shelf ASP systems. We establish the competitiveness of our approach by empirically contrasting it to the best known bounds obtained so far via dedicated implementations. Furthermore, we extend the teaspoon system to multi-objective course timetabling and consider minimal perturbation problems.}, language = {en} } @misc{NeubauerHaubeltWankoetal.2018, author = {Neubauer, Kai and Haubelt, Christian and Wanko, Philipp and Schaub, Torsten}, title = {Utilizing quad-trees for efficient design space exploration with partial assignment evaluation}, series = {2018 23rd Asia and South Pacific Design Automation Conference (ASP-DAC)}, journal = {2018 23rd Asia and South Pacific Design Automation Conference (ASP-DAC)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5090-0602-1}, issn = {2153-6961}, doi = {10.1109/ASPDAC.2018.8297362}, pages = {434 -- 439}, year = {2018}, abstract = {Recently, it has been shown that constraint-based symbolic solving techniques offer an efficient way for deciding binding and routing options in order to obtain a feasible system level implementation. In combination with various background theories, a feasibility analysis of the resulting system may already be performed on partial solutions. That is, infeasible subsets of mapping and routing options can be pruned early in the decision process, which fastens the solving accordingly. However, allowing a proper design space exploration including multi-objective optimization also requires an efficient structure for storing and managing non-dominated solutions. In this work, we propose and study the usage of the Quad-Tree data structure in the context of partial assignment evaluation during system synthesis. Out experiments show that unnecessary dominance checks can be avoided, which indicates a preference of Quad-Trees over a commonly used list-based implementation for large combinatorial optimization problems.}, language = {en} } @article{GebserKaminskiKaufmannetal.2018, author = {Gebser, Martin and Kaminski, Roland and Kaufmann, Benjamin and L{\"u}hne, Patrick and Obermeier, Philipp and Ostrowski, Max and Romero Davila, Javier and Schaub, Torsten and Schellhorn, Sebastian and Wanko, Philipp}, title = {The Potsdam Answer Set Solving Collection 5.0}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0528-x}, pages = {181 -- 182}, year = {2018}, abstract = {The Potsdam answer set solving collection, or Potassco for short, bundles various tools implementing and/or applying answer set programming. The article at hand succeeds an earlier description of the Potassco project published in Gebser et al. (AI Commun 24(2):107-124, 2011). Hence, we concentrate in what follows on the major features of the most recent, fifth generation of the ASP system clingo and highlight some recent resulting application systems.}, language = {en} } @article{HaubeltNeubauerSchaubetal.2018, author = {Haubelt, Christian and Neubauer, Kai and Schaub, Torsten and Wanko, Philipp}, title = {Design space exploration with answer set programming}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0530-3}, pages = {205 -- 206}, year = {2018}, abstract = {The aim of our project design space exploration with answer set programming is to develop a general framework based on Answer Set Programming (ASP) that finds valid solutions to the system design problem and simultaneously performs Design Space Exploration (DSE) to find the most favorable alternatives. We leverage recent developments in ASP solving that allow for tight integration of background theories to create a holistic framework for effective DSE.}, language = {en} } @article{PrasseKnaebelMachlicaetal.2019, author = {Prasse, Paul and Knaebel, Rene and Machlica, Lukas and Pevny, Tomas and Scheffer, Tobias}, title = {Joint detection of malicious domains and infected clients}, series = {Machine learning}, volume = {108}, journal = {Machine learning}, number = {8-9}, publisher = {Springer}, address = {Dordrecht}, issn = {0885-6125}, doi = {10.1007/s10994-019-05789-z}, pages = {1353 -- 1368}, year = {2019}, abstract = {Detection of malware-infected computers and detection of malicious web domains based on their encrypted HTTPS traffic are challenging problems, because only addresses, timestamps, and data volumes are observable. The detection problems are coupled, because infected clients tend to interact with malicious domains. Traffic data can be collected at a large scale, and antivirus tools can be used to identify infected clients in retrospect. Domains, by contrast, have to be labeled individually after forensic analysis. We explore transfer learning based on sluice networks; this allows the detection models to bootstrap each other. In a large-scale experimental study, we find that the model outperforms known reference models and detects previously unknown malware, previously unknown malware families, and previously unknown malicious domains.}, language = {en} } @phdthesis{AbdelwahabHusseinAbdelwahabElsayed2019, author = {Abdelwahab Hussein Abdelwahab Elsayed, Ahmed}, title = {Probabilistic, deep, and metric learning for biometric identification from eye movements}, doi = {10.25932/publishup-46798}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-467980}, school = {Universit{\"a}t Potsdam}, pages = {vi, 65}, year = {2019}, abstract = {A central insight from psychological studies on human eye movements is that eye movement patterns are highly individually characteristic. They can, therefore, be used as a biometric feature, that is, subjects can be identified based on their eye movements. This thesis introduces new machine learning methods to identify subjects based on their eye movements while viewing arbitrary content. The thesis focuses on probabilistic modeling of the problem, which has yielded the best results in the most recent literature. The thesis studies the problem in three phases by proposing a purely probabilistic, probabilistic deep learning, and probabilistic deep metric learning approach. In the first phase, the thesis studies models that rely on psychological concepts about eye movements. Recent literature illustrates that individual-specific distributions of gaze patterns can be used to accurately identify individuals. In these studies, models were based on a simple parametric family of distributions. Such simple parametric models can be robustly estimated from sparse data, but have limited flexibility to capture the differences between individuals. Therefore, this thesis proposes a semiparametric model of gaze patterns that is flexible yet robust for individual identification. These patterns can be understood as domain knowledge derived from psychological literature. Fixations and saccades are examples of simple gaze patterns. The proposed semiparametric densities are drawn under a Gaussian process prior centered at a simple parametric distribution. Thus, the model will stay close to the parametric class of densities if little data is available, but it can also deviate from this class if enough data is available, increasing the flexibility of the model. The proposed method is evaluated on a large-scale dataset, showing significant improvements over the state-of-the-art. Later, the thesis replaces the model based on gaze patterns derived from psychological concepts with a deep neural network that can learn more informative and complex patterns from raw eye movement data. As previous work has shown that the distribution of these patterns across a sequence is informative, a novel statistical aggregation layer called the quantile layer is introduced. It explicitly fits the distribution of deep patterns learned directly from the raw eye movement data. The proposed deep learning approach is end-to-end learnable, such that the deep model learns to extract informative, short local patterns while the quantile layer learns to approximate the distributions of these patterns. Quantile layers are a generic approach that can converge to standard pooling layers or have a more detailed description of the features being pooled, depending on the problem. The proposed model is evaluated in a large-scale study using the eye movements of subjects viewing arbitrary visual input. The model improves upon the standard pooling layers and other statistical aggregation layers proposed in the literature. It also improves upon the state-of-the-art eye movement biometrics by a wide margin. Finally, for the model to identify any subject — not just the set of subjects it is trained on — a metric learning approach is developed. Metric learning learns a distance function over instances. The metric learning model maps the instances into a metric space, where sequences of the same individual are close, and sequences of different individuals are further apart. This thesis introduces a deep metric learning approach with distributional embeddings. The approach represents sequences as a set of continuous distributions in a metric space; to achieve this, a new loss function based on Wasserstein distances is introduced. The proposed method is evaluated on multiple domains besides eye movement biometrics. This approach outperforms the state of the art in deep metric learning in several domains while also outperforming the state of the art in eye movement biometrics.}, language = {en} } @misc{Strickroth2019, author = {Strickroth, Sven}, title = {PLATON}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {804}, issn = {1866-8372}, doi = {10.25932/publishup-44188}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441887}, pages = {28}, year = {2019}, abstract = {Lesson planning is both an important and demanding task—especially as part of teacher training. This paper presents the requirements for a lesson planning system and evaluates existing systems regarding these requirements. One major drawback of existing software tools is that most are limited to a text- or form-based representation of the lesson designs. In this article, a new approach with a graphical, time-based representation with (automatic) analyses methods is proposed and the system architecture and domain model are described in detail. The approach is implemented in an interactive, web-based prototype called PLATON, which additionally supports the management of lessons in units as well as the modelling of teacher and student-generated resources. The prototype was evaluated in a study with 61 prospective teachers (bachelor's and master's preservice teachers as well as teacher trainees in post-university teacher training) in Berlin, Germany, with a focus on usability. The results show that this approach proofed usable for lesson planning and offers positive effects for the perception of time and self-reflection.}, language = {en} } @article{MetrefCosmeLeSommeretal.2019, author = {Metref, Sammy and Cosme, Emmanuel and Le Sommer, Julien and Poel, Nora and Brankart, Jean-Michel and Verron, Jacques and Gomez Navarro, Laura}, title = {Reduction of spatially structured errors in Wide-Swath altimetric satellite data using data assimilation}, series = {Remote sensing}, volume = {11}, journal = {Remote sensing}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {2072-4292}, doi = {10.3390/rs11111336}, pages = {21}, year = {2019}, abstract = {The Surface Water and Ocean Topography (SWOT) mission is a next generation satellite mission expected to provide a 2 km-resolution observation of the sea surface height (SSH) on a two-dimensional swath. Processing SWOT data will be challenging because of the large amount of data, the mismatch between a high spatial resolution and a low temporal resolution, and the observation errors. The present paper focuses on the reduction of the spatially structured errors of SWOT SSH data. It investigates a new error reduction method and assesses its performance in an observing system simulation experiment. The proposed error-reduction method first projects the SWOT SSH onto a subspace spanned by the SWOT spatially structured errors. This projection is removed from the SWOT SSH to obtain a detrended SSH. The detrended SSH is then processed within an ensemble data assimilation analysis to retrieve a full SSH field. In the latter step, the detrending is applied to both the SWOT data and an ensemble of model-simulated SSH fields. Numerical experiments are performed with synthetic SWOT observations and an ensemble from a North Atlantic, 1/60 degrees simulation of the ocean circulation (NATL60). The data assimilation analysis is carried out with an ensemble Kalman filter. The results are assessed with root mean square errors, power spectrum density, and spatial coherence. They show that a significant part of the large scale SWOT errors is reduced. The filter analysis also reduces the small scale errors and allows for an accurate recovery of the energy of the signal down to 25 km scales. In addition, using the SWOT nadir data to adjust the SSH detrending further reduces the errors.}, language = {en} } @misc{Przybylla2019, author = {Przybylla, Mareen}, title = {Interactive objects in physical computing and their role in the learning process}, series = {Constructivist foundations}, volume = {14}, journal = {Constructivist foundations}, number = {3}, publisher = {Vrije Univ.}, address = {Bussels}, issn = {1782-348X}, pages = {264 -- 266}, year = {2019}, abstract = {The target article discusses the question of how educational makerspaces can become places supportive of knowledge construction. This question is too often neglected by people who run makerspaces, as they mostly explain how to use different tools and focus on the creation of a product. In makerspaces, often pupils also engage in physical computing activities and thus in the creation of interactive artifacts containing embedded systems, such as smart shoes or wristbands, plant monitoring systems or drink mixing machines. This offers the opportunity to reflect on teaching physical computing in computer science education, where similarly often the creation of the product is so strongly focused upon that the reflection of the learning process is pushed into the background.}, language = {en} } @article{PousttchiGleiss2019, author = {Pousttchi, Key and Gleiß, Alexander}, title = {Surrounded by middlemen - how multi-sided platforms change the insurance industry}, series = {Electron Markets}, volume = {29}, journal = {Electron Markets}, number = {4}, publisher = {Springer}, address = {Heidelberg}, issn = {1019-6781}, doi = {10.1007/s12525-019-00363-w}, pages = {609 -- 629}, year = {2019}, abstract = {Multi-sided platforms (MSP) strongly affect markets and play a crucial part within the digital and networked economy. Although empirical evidence indicates their occurrence in many industries, research has not investigated the game-changing impact of MSP on traditional markets to a sufficient extent. More specifically, we have little knowledge of how MSP affect value creation and customer interaction in entire markets, exploiting the potential of digital technologies to offer new value propositions. Our paper addresses this research gap and provides an initial systematic approach to analyze the impact of MSP on the insurance industry. For this purpose, we analyze the state of the art in research and practice in order to develop a reference model of the value network for the insurance industry. On this basis, we conduct a case-study analysis to discover and analyze roles which are occupied or even newly created by MSP. As a final step, we categorize MSP with regard to their relation to traditional insurance companies, resulting in a classification scheme with four MSP standard types: Competition, Coordination, Cooperation, Collaboration.}, language = {en} } @article{WaitelonisJuergesSack2019, author = {Waitelonis, J{\"o}rg and J{\"u}rges, Henrik and Sack, Harald}, title = {Remixing entity linking evaluation datasets for focused benchmarking}, series = {Semantic Web}, volume = {10}, journal = {Semantic Web}, number = {2}, publisher = {IOS Press}, address = {Amsterdam}, issn = {1570-0844}, doi = {10.3233/SW-180334}, pages = {385 -- 412}, year = {2019}, abstract = {In recent years, named entity linking (NEL) tools were primarily developed in terms of a general approach, whereas today numerous tools are focusing on specific domains such as e.g. the mapping of persons and organizations only, or the annotation of locations or events in microposts. However, the available benchmark datasets necessary for the evaluation of NEL tools do not reflect this focalizing trend. We have analyzed the evaluation process applied in the NEL benchmarking framework GERBIL [in: Proceedings of the 24th International Conference on World Wide Web (WWW'15), International World Wide Web Conferences Steering Committee, Republic and Canton of Geneva, Switzerland, 2015, pp. 1133-1143, Semantic Web 9(5) (2018), 605-625] and all its benchmark datasets. Based on these insights we have extended the GERBIL framework to enable a more fine grained evaluation and in depth analysis of the available benchmark datasets with respect to different emphases. This paper presents the implementation of an adaptive filter for arbitrary entities and customized benchmark creation as well as the automated determination of typical NEL benchmark dataset properties, such as the extent of content-related ambiguity and diversity. These properties are integrated on different levels, which also enables to tailor customized new datasets out of the existing ones by remixing documents based on desired emphases. Besides a new system library to enrich provided NIF [in: International Semantic Web Conference (ISWC'13), Lecture Notes in Computer Science, Vol. 8219, Springer, Berlin, Heidelberg, 2013, pp. 98-113] datasets with statistical information, best practices for dataset remixing are presented, and an in depth analysis of the performance of entity linking systems on special focus datasets is presented.}, language = {en} } @misc{FichteHecherMeier2019, author = {Fichte, Johannes Klaus and Hecher, Markus and Meier, Arne}, title = {Counting Complexity for Reasoning in Abstract Argumentation}, series = {The Thirty-Third AAAI Conference on Artificial Intelligence, the Thirty-First Innovative Applications of Artificial Intelligence Conference, the Ninth AAAI Symposium on Educational Advances in Artificial Intelligence}, journal = {The Thirty-Third AAAI Conference on Artificial Intelligence, the Thirty-First Innovative Applications of Artificial Intelligence Conference, the Ninth AAAI Symposium on Educational Advances in Artificial Intelligence}, publisher = {AAAI Press}, address = {Palo Alto}, isbn = {978-1-57735-809-1}, pages = {2827 -- 2834}, year = {2019}, abstract = {In this paper, we consider counting and projected model counting of extensions in abstract argumentation for various semantics. When asking for projected counts we are interested in counting the number of extensions of a given argumentation framework while multiple extensions that are identical when restricted to the projected arguments count as only one projected extension. We establish classical complexity results and parameterized complexity results when the problems are parameterized by treewidth of the undirected argumentation graph. To obtain upper bounds for counting projected extensions, we introduce novel algorithms that exploit small treewidth of the undirected argumentation graph of the input instance by dynamic programming (DP). Our algorithms run in time double or triple exponential in the treewidth depending on the considered semantics. Finally, we take the exponential time hypothesis (ETH) into account and establish lower bounds of bounded treewidth algorithms for counting extensions and projected extension.}, language = {en} } @phdthesis{Schneider2019, author = {Schneider, Jan Niklas}, title = {Computational approaches for emotion research}, doi = {10.25932/publishup-45927}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459275}, school = {Universit{\"a}t Potsdam}, pages = {xv, 145}, year = {2019}, abstract = {Emotionen sind ein zentrales Element menschlichen Erlebens und spielen eine wichtige Rolle bei der Entscheidungsfindung. Diese Dissertation identifiziert drei methodische Probleme der aktuellen Emotionsforschung und zeigt auf, wie diese mittels computergest{\"u}tzter Methoden gel{\"o}st werden k{\"o}nnen. Dieser Ansatz wird in drei Forschungsprojekten demonstriert, die die Entwicklung solcher Methoden sowie deren Anwendung auf konkrete Forschungsfragen beschreiben. Das erste Projekt beschreibt ein Paradigma welches es erm{\"o}glicht, die subjektive und objektive Schwierigkeit der Emotionswahrnehmung zu messen. Dar{\"u}ber hinaus erm{\"o}glicht es die Verwendung einer beliebigen Anzahl von Emotionskategorien im Vergleich zu den {\"u}blichen sechs Kategorien der Basisemotionen. Die Ergebnisse deuten auf eine Zunahme der Schwierigkeiten bei der Wahrnehmung von Emotionen mit zunehmendem Alter der Darsteller hin und liefern Hinweise darauf, dass junge Erwachsene, {\"a}ltere Menschen und M{\"a}nner ihre Schwierigkeit bei der Wahrnehmung von Emotionen untersch{\"a}tzen. Weitere Analysen zeigten eine geringe Relevanz personenbezogener Variablen und deuteten darauf hin, dass die Schwierigkeit der Emotionswahrnehmung vornehmlich durch die Auspr{\"a}gung der Wertigkeit des Ausdrucks bestimmt wird. Das zweite Projekt zeigt am Beispiel von Arousal, einem etablierten, aber vagen Konstrukt der Emotionsforschung, wie Face-Tracking-Daten dazu genutzt werden k{\"o}nnen solche Konstrukte zu sch{\"a}rfen. Es beschreibt, wie aus Face-Tracking-Daten Maße f{\"u}r die Entfernung, Geschwindigkeit und Beschleunigung von Gesichtsausdr{\"u}cken berechnet werden k{\"o}nnen. Das Projekt untersuchte wie diesen Maße mit der Arousal-Wahrnehmung in Menschen mit und ohne Autismus zusammenh{\"a}ngen. Der Abstand zum Neutralgesicht war pr{\"a}diktiv f{\"u}r die Arousal-Bewertungen in beiden Gruppen. Die Ergebnisse deuten auf eine qualitativ {\"a}hnliche Wahrnehmung von Arousal f{\"u}r Menschen mit und ohne Autismus hin. Im dritten Projekt stellen wir die Partial-Least-Squares-Analyse als allgemeine Methode vor, um eine optimale Repr{\"a}sentation zur Verkn{\"u}pfung zweier hochdimensionale Datens{\"a}tze zu finden. Das Projekt demonstriert die Anwendbarkeit dieser Methode in der Emotionsforschung anhand der Frage nach Unterschieden in der Emotionswahrnehmung zwischen M{\"a}nnern und Frauen. Wir konnten zeigen, dass die emotionale Wahrnehmung von Frauen systematisch mehr Varianz der Gesichtsausdr{\"u}cke erfasst und dass signifikante Unterschiede in der Art und Weise bestehen, wie Frauen und M{\"a}nner einige Gesichtsausdr{\"u}cke wahrnehmen. Diese konnten wir als dynamische Gesichtsausdr{\"u}cke visualisieren. Um die Anwendung der entwickelten Methode f{\"u}r die Forschungsgemeinschaft zu erleichtern, wurde ein Software-Paket f{\"u}r die Statistikumgebung R geschrieben. Zudem wurde eine Website entwickelt (thisemotiondoesnotexist.com), die es Besuchern erlaubt, ein Partial-Least-Squares-Modell von Emotionsbewertungen und Face-Tracking-Daten interaktiv zu erkunden, um die entwickelte Methode zu verbreiten und ihren Nutzen f{\"u}r die Emotionsforschung zu illustrieren.}, language = {en} } @article{Strickroth2019, author = {Strickroth, Sven}, title = {PLATON}, series = {Education Sciences}, volume = {9}, journal = {Education Sciences}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2227-7102}, doi = {10.3390/educsci9040254}, pages = {26}, year = {2019}, abstract = {Lesson planning is both an important and demanding task—especially as part of teacher training. This paper presents the requirements for a lesson planning system and evaluates existing systems regarding these requirements. One major drawback of existing software tools is that most are limited to a text- or form-based representation of the lesson designs. In this article, a new approach with a graphical, time-based representation with (automatic) analyses methods is proposed and the system architecture and domain model are described in detail. The approach is implemented in an interactive, web-based prototype called PLATON, which additionally supports the management of lessons in units as well as the modelling of teacher and student-generated resources. The prototype was evaluated in a study with 61 prospective teachers (bachelor's and master's preservice teachers as well as teacher trainees in post-university teacher training) in Berlin, Germany, with a focus on usability. The results show that this approach proofed usable for lesson planning and offers positive effects for the perception of time and self-reflection.}, language = {en} } @phdthesis{Tiwari2019, author = {Tiwari, Abhishek}, title = {Enhancing Users' Privacy: Static Resolution of the Dynamic Properties of Android}, school = {Universit{\"a}t Potsdam}, pages = {xiii, 111}, year = {2019}, abstract = {The usage of mobile devices is rapidly growing with Android being the most prevalent mobile operating system. Thanks to the vast variety of mobile applications, users are preferring smartphones over desktops for day to day tasks like Internet surfing. Consequently, smartphones store a plenitude of sensitive data. This data together with the high values of smartphones make them an attractive target for device/data theft (thieves/malicious applications). Unfortunately, state-of-the-art anti-theft solutions do not work if they do not have an active network connection, e.g., if the SIM card was removed from the device. In the majority of these cases, device owners permanently lose their smartphone together with their personal data, which is even worse. Apart from that malevolent applications perform malicious activities to steal sensitive information from smartphones. Recent research considered static program analysis to detect dangerous data leaks. These analyses work well for data leaks due to inter-component communication, but suffer from shortcomings for inter-app communication with respect to precision, soundness, and scalability. This thesis focuses on enhancing users' privacy on Android against physical device loss/theft and (un)intentional data leaks. It presents three novel frameworks: (1) ThiefTrap, an anti-theft framework for Android, (2) IIFA, a modular inter-app intent information flow analysis of Android applications, and (3) PIAnalyzer, a precise approach for PendingIntent vulnerability analysis. ThiefTrap is based on a novel concept of an anti-theft honeypot account that protects the owner's data while preventing a thief from resetting the device. We implemented the proposed scheme and evaluated it through an empirical user study with 35 participants. In this study, the owner's data could be protected, recovered, and anti-theft functionality could be performed unnoticed from the thief in all cases. IIFA proposes a novel approach for Android's inter-component/inter-app communication (ICC/IAC) analysis. Our main contribution is the first fully automatic, sound, and precise ICC/IAC information flow analysis that is scalable for realistic apps due to modularity, avoiding combinatorial explosion: Our approach determines communicating apps using short summaries rather than inlining intent calls between components and apps, which requires simultaneously analyzing all apps installed on a device. We evaluate IIFA in terms of precision, recall, and demonstrate its scalability to a large corpus of real-world apps. IIFA reports 62 problematic ICC-/IAC-related information flows via two or more apps/components. PIAnalyzer proposes a novel approach to analyze PendingIntent related vulnerabilities. PendingIntents are a powerful and universal feature of Android for inter-component communication. We empirically evaluate PIAnalyzer on a set of 1000 randomly selected applications and find 1358 insecure usages of PendingIntents, including 70 severe vulnerabilities.}, language = {en} } @phdthesis{Boehne2019, author = {B{\"o}hne, Sebastian}, title = {Different degrees of formality}, doi = {10.25932/publishup-42379}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-423795}, school = {Universit{\"a}t Potsdam}, pages = {VI, 167}, year = {2019}, abstract = {In this thesis we introduce the concept of the degree of formality. It is directed against a dualistic point of view, which only distinguishes between formal and informal proofs. This dualistic attitude does not respect the differences between the argumentations classified as informal and it is unproductive because the individual potential of the respective argumentation styles cannot be appreciated and remains untapped. This thesis has two parts. In the first of them we analyse the concept of the degree of formality (including a discussion about the respective benefits for each degree) while in the second we demonstrate its usefulness in three case studies. In the first case study we will repair Haskell B. Curry's view of mathematics, which incidentally is of great importance in the first part of this thesis, in light of the different degrees of formality. In the second case study we delineate how awareness of the different degrees of formality can be used to help students to learn how to prove. Third, we will show how the advantages of proofs of different degrees of formality can be combined by the development of so called tactics having a medium degree of formality. Together the three case studies show that the degrees of formality provide a convincing solution to the problem of untapped potential.}, language = {en} } @misc{AlhosseiniAlmodarresiYasinBinTareafNajafietal.2019, author = {Alhosseini Almodarresi Yasin, Seyed Ali and Bin Tareaf, Raad and Najafi, Pejman and Meinel, Christoph}, title = {Detect me if you can}, series = {Companion Proceedings of The 2019 World Wide Web Conference}, journal = {Companion Proceedings of The 2019 World Wide Web Conference}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-6675-5}, doi = {10.1145/3308560.3316504}, pages = {148 -- 153}, year = {2019}, abstract = {Spam Bots have become a threat to online social networks with their malicious behavior, posting misinformation messages and influencing online platforms to fulfill their motives. As spam bots have become more advanced over time, creating algorithms to identify bots remains an open challenge. Learning low-dimensional embeddings for nodes in graph structured data has proven to be useful in various domains. In this paper, we propose a model based on graph convolutional neural networks (GCNN) for spam bot detection. Our hypothesis is that to better detect spam bots, in addition to defining a features set, the social graph must also be taken into consideration. GCNNs are able to leverage both the features of a node and aggregate the features of a node's neighborhood. We compare our approach, with two methods that work solely on a features set and on the structure of the graph. To our knowledge, this work is the first attempt of using graph convolutional neural networks in spam bot detection.}, language = {en} } @misc{CabalarFandinoSchaubetal.2019, author = {Cabalar, Pedro and Fandi{\~n}o, Jorge and Schaub, Torsten and Schellhorn, Sebastian}, title = {Lower Bound Founded Logic of Here-and-There}, series = {Logics in Artificial Intelligence}, volume = {11468}, journal = {Logics in Artificial Intelligence}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-19570-0}, issn = {0302-9743}, doi = {10.1007/978-3-030-19570-0_34}, pages = {509 -- 525}, year = {2019}, abstract = {A distinguishing feature of Answer Set Programming is that all atoms belonging to a stable model must be founded. That is, an atom must not only be true but provably true. This can be made precise by means of the constructive logic of Here-and-There, whose equilibrium models correspond to stable models. One way of looking at foundedness is to regard Boolean truth values as ordered by letting true be greater than false. Then, each Boolean variable takes the smallest truth value that can be proven for it. This idea was generalized by Aziz to ordered domains and applied to constraint satisfaction problems. As before, the idea is that a, say integer, variable gets only assigned to the smallest integer that can be justified. In this paper, we present a logical reconstruction of Aziz' idea in the setting of the logic of Here-and-There. More precisely, we start by defining the logic of Here-and-There with lower bound founded variables along with its equilibrium models and elaborate upon its formal properties. Finally, we compare our approach with related ones and sketch future work.}, language = {en} } @article{CabalarFandinoSchaubetal.2019, author = {Cabalar, Pedro and Fandi{\~n}o, Jorge and Schaub, Torsten and Schellhorn, Sebastian}, title = {Gelfond-Zhang aggregates as propositional formulas}, series = {Artificial intelligence}, volume = {274}, journal = {Artificial intelligence}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0004-3702}, doi = {10.1016/j.artint.2018.10.007}, pages = {26 -- 43}, year = {2019}, abstract = {Answer Set Programming (ASP) has become a popular and widespread paradigm for practical Knowledge Representation thanks to its expressiveness and the available enhancements of its input language. One of such enhancements is the use of aggregates, for which different semantic proposals have been made. In this paper, we show that any ASP aggregate interpreted under Gelfond and Zhang's (GZ) semantics can be replaced (under strong equivalence) by a propositional formula. Restricted to the original GZ syntax, the resulting formula is reducible to a disjunction of conjunctions of literals but the formulation is still applicable even when the syntax is extended to allow for arbitrary formulas (including nested aggregates) in the condition. Once GZ-aggregates are represented as formulas, we establish a formal comparison (in terms of the logic of Here-and-There) to Ferraris' (F) aggregates, which are defined by a different formula translation involving nested implications. In particular, we prove that if we replace an F-aggregate by a GZ-aggregate in a rule head, we do not lose answer sets (although more can be gained). This extends the previously known result that the opposite happens in rule bodies, i.e., replacing a GZ-aggregate by an F-aggregate in the body may yield more answer sets. Finally, we characterize a class of aggregates for which GZ- and F-semantics coincide.}, language = {en} } @misc{Fandino2019, author = {Fandi{\~n}o, Jorge}, title = {Founded (auto)epistemic equilibrium logic satisfies epistemic splitting}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1060}, issn = {1866-8372}, doi = {10.25932/publishup-46968}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-469685}, pages = {671 -- 687}, year = {2019}, abstract = {In a recent line of research, two familiar concepts from logic programming semantics (unfounded sets and splitting) were extrapolated to the case of epistemic logic programs. The property of epistemic splitting provides a natural and modular way to understand programs without epistemic cycles but, surprisingly, was only fulfilled by Gelfond's original semantics (G91), among the many proposals in the literature. On the other hand, G91 may suffer from a kind of self-supported, unfounded derivations when epistemic cycles come into play. Recently, the absence of these derivations was also formalised as a property of epistemic semantics called foundedness. Moreover, a first semantics proved to satisfy foundedness was also proposed, the so-called Founded Autoepistemic Equilibrium Logic (FAEEL). In this paper, we prove that FAEEL also satisfies the epistemic splitting property something that, together with foundedness, was not fulfilled by any other approach up to date. To prove this result, we provide an alternative characterisation of FAEEL as a combination of G91 with a simpler logic we called Founded Epistemic Equilibrium Logic (FEEL), which is somehow an extrapolation of the stable model semantics to the modal logic S5.}, language = {en} } @misc{AguadoCabalarFandinoetal.2019, author = {Aguado, Felicidad and Cabalar, Pedro and Fandi{\~n}o, Jorge and Pearce, David and Perez, Gilberto and Vidal, Concepcion}, title = {Revisiting explicit negation in answer set programming}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1104}, issn = {1866-8372}, doi = {10.25932/publishup-46969}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-469697}, pages = {908 -- 924}, year = {2019}, abstract = {A common feature in Answer Set Programming is the use of a second negation, stronger than default negation and sometimes called explicit, strong or classical negation. This explicit negation is normally used in front of atoms, rather than allowing its use as a regular operator. In this paper we consider the arbitrary combination of explicit negation with nested expressions, as those defined by Lifschitz, Tang and Turner. We extend the concept of reduct for this new syntax and then prove that it can be captured by an extension of Equilibrium Logic with this second negation. We study some properties of this variant and compare to the already known combination of Equilibrium Logic with Nelson's strong negation.}, language = {en} } @article{AguadoCabalarFandinoetal.2019, author = {Aguado, Felicidad and Cabalar, Pedro and Fandi{\~n}o, Jorge and Pearce, David and Perez, Gilberto and Vidal, Concepcion}, title = {Forgetting auxiliary atoms in forks}, series = {Artificial intelligence}, volume = {275}, journal = {Artificial intelligence}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0004-3702}, doi = {10.1016/j.artint.2019.07.005}, pages = {575 -- 601}, year = {2019}, abstract = {In this work we tackle the problem of checking strong equivalence of logic programs that may contain local auxiliary atoms, to be removed from their stable models and to be forbidden in any external context. We call this property projective strong equivalence (PSE). It has been recently proved that not any logic program containing auxiliary atoms can be reformulated, under PSE, as another logic program or formula without them - this is known as strongly persistent forgetting. In this paper, we introduce a conservative extension of Equilibrium Logic and its monotonic basis, the logic of Here-and-There, in which we deal with a new connective '|' we call fork. We provide a semantic characterisation of PSE for forks and use it to show that, in this extension, it is always possible to forget auxiliary atoms under strong persistence. We further define when the obtained fork is representable as a regular formula.}, language = {en} } @article{AguadoCabalarFandinoetal.2019, author = {Aguado, Felicidad and Cabalar, Pedro and Fandi{\~n}o, Jorge and Pearce, David and Perez, Gilberto and Vidal-Peracho, Concepcion}, title = {Revisiting Explicit Negation in Answer Set Programming}, series = {Theory and practice of logic programming}, volume = {19}, journal = {Theory and practice of logic programming}, number = {5-6}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068419000267}, pages = {908 -- 924}, year = {2019}, language = {en} } @article{DimopoulosGebserLuehneetal.2019, author = {Dimopoulos, Yannis and Gebser, Martin and L{\"u}hne, Patrick and Romero Davila, Javier and Schaub, Torsten}, title = {plasp 3}, series = {Theory and practice of logic programming}, volume = {19}, journal = {Theory and practice of logic programming}, number = {3}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068418000583}, pages = {477 -- 504}, year = {2019}, abstract = {We describe the new version of the Planning Domain Definition Language (PDDL)-to-Answer Set Programming (ASP) translator plasp. First, it widens the range of accepted PDDL features. Second, it contains novel planning encodings, some inspired by Satisfiability Testing (SAT) planning and others exploiting ASP features such as well-foundedness. All of them are designed for handling multivalued fluents in order to capture both PDDL as well as SAS planning formats. Third, enabled by multishot ASP solving, it offers advanced planning algorithms also borrowed from SAT planning. As a result, plasp provides us with an ASP-based framework for studying a variety of planning techniques in a uniform setting. Finally, we demonstrate in an empirical analysis that these techniques have a significant impact on the performance of ASP planning.}, language = {en} } @article{FriouxSchaubSchellhornetal.2019, author = {Frioux, Cl{\´e}mence and Schaub, Torsten and Schellhorn, Sebastian and Siegel, Anne and Wanko, Philipp}, title = {Hybrid metabolic network completion}, series = {Theory and practice of logic programming}, volume = {19}, journal = {Theory and practice of logic programming}, number = {1}, publisher = {Cambridge University Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068418000455}, pages = {83 -- 108}, year = {2019}, abstract = {Metabolic networks play a crucial role in biology since they capture all chemical reactions in an organism. While there are networks of high quality for many model organisms, networks for less studied organisms are often of poor quality and suffer from incompleteness. To this end, we introduced in previous work an answer set programming (ASP)-based approach to metabolic network completion. Although this qualitative approach allows for restoring moderately degraded networks, it fails to restore highly degraded ones. This is because it ignores quantitative constraints capturing reaction rates. To address this problem, we propose a hybrid approach to metabolic network completion that integrates our qualitative ASP approach with quantitative means for capturing reaction rates. We begin by formally reconciling existing stoichiometric and topological approaches to network completion in a unified formalism. With it, we develop a hybrid ASP encoding and rely upon the theory reasoning capacities of the ASP system dingo for solving the resulting logic program with linear constraints over reals. We empirically evaluate our approach by means of the metabolic network of Escherichia coli. Our analysis shows that our novel approach yields greatly superior results than obtainable from purely qualitative or quantitative approaches.}, language = {en} } @phdthesis{Ashouri2020, author = {Ashouri, Mohammadreza}, title = {TrainTrap}, school = {Universit{\"a}t Potsdam}, pages = {XIX, 103}, year = {2020}, language = {en} } @article{EverardoPerezOsorio2020, author = {Everardo P{\´e}rez, Flavio Omar and Osorio, Mauricio}, title = {Towards an answer set programming methodology for constructing programs following a semi-automatic approach}, series = {Electronic notes in theoretical computer science}, volume = {354}, journal = {Electronic notes in theoretical computer science}, publisher = {Elsevier}, address = {Amsterdam [u.a.]}, issn = {1571-0661}, doi = {10.1016/j.entcs.2020.10.004}, pages = {29 -- 44}, year = {2020}, abstract = {Answer Set Programming (ASP) is a successful rule-based formalism for modeling and solving knowledge-intense combinatorial (optimization) problems. Despite its success in both academic and industry, open challenges like automatic source code optimization, and software engineering remains. This is because a problem encoded into an ASP might not have the desired solving performance compared to an equivalent representation. Motivated by these two challenges, this paper has three main contributions. First, we propose a developing process towards a methodology to implement ASP programs, being faithful to existing methods. Second, we present ASP encodings that serve as the basis from the developing process. Third, we demonstrate the use of ASP to reverse the standard solving process. That is, knowing answer sets in advance, and desired strong equivalent properties, "we" exhaustively reconstruct ASP programs if they exist. This paper was originally motivated by the search of propositional formulas (if they exist) that represent the semantics of a new aggregate operator. Particularly, a parity aggregate. This aggregate comes as an improvement from the already existing parity (xor) constraints from xorro, where lacks expressiveness, even though these constraints fit perfectly for reasoning modes like sampling or model counting. To this end, this extended version covers the fundaments from parity constraints as well as the xorro system. Hence, we delve a little more in the examples and the proposed methodology over parity constraints. Finally, we discuss our results by showing the only representation available, that satisfies different properties from the classical logic xor operator, which is also consistent with the semantics of parity constraints from xorro.}, language = {en} } @article{HollmannFrohmeEndrullatetal.2020, author = {Hollmann, Susanne and Frohme, Marcus and Endrullat, Christoph and Kremer, Andreas and D'Elia, Domenica and Regierer, Babette and Nechyporenko, Alina}, title = {Ten simple rules on how to write a standard operating procedure}, series = {PLOS Computational Biology}, volume = {16}, journal = {PLOS Computational Biology}, number = {9}, publisher = {PLOS}, address = {San Francisco}, pages = {10}, year = {2020}, abstract = {Research publications and data nowadays should be publicly available on the internet and, theoretically, usable for everyone to develop further research, products, or services. The long-term accessibility of research data is, therefore, fundamental in the economy of the research production process. However, the availability of data is not sufficient by itself, but also their quality must be verifiable. Measures to ensure reuse and reproducibility need to include the entire research life cycle, from the experimental design to the generation of data, quality control, statistical analysis, interpretation, and validation of the results. Hence, high-quality records, particularly for providing a string of documents for the verifiable origin of data, are essential elements that can act as a certificate for potential users (customers). These records also improve the traceability and transparency of data and processes, therefore, improving the reliability of results. Standards for data acquisition, analysis, and documentation have been fostered in the last decade driven by grassroot initiatives of researchers and organizations such as the Research Data Alliance (RDA). Nevertheless, what is still largely missing in the life science academic research are agreed procedures for complex routine research workflows. Here, well-crafted documentation like standard operating procedures (SOPs) offer clear direction and instructions specifically designed to avoid deviations as an absolute necessity for reproducibility. Therefore, this paper provides a standardized workflow that explains step by step how to write an SOP to be used as a starting point for appropriate research documentation.}, language = {en} } @article{Stede2020, author = {Stede, Manfred}, title = {From connectives to coherence relations}, series = {Revue roumaine de linguistique : RRL = Romanian review of linguistics}, volume = {65}, journal = {Revue roumaine de linguistique : RRL = Romanian review of linguistics}, number = {3}, publisher = {Ed. Academiei Rom{\^a}ne}, address = {Bucure{\c{s}}ti}, issn = {0035-3957}, pages = {213 -- 233}, year = {2020}, abstract = {The notion of coherence relations is quite widely accepted in general, but concrete proposals differ considerably on the questions of how they should be motivated, which relations are to be assumed, and how they should be defined. This paper takes a "bottom-up" perspective by assessing the contribution made by linguistic signals (connectives), using insights from the relevant literature as well as verification by practical text annotation. We work primarily with the German language here and focus on the realm of contrast. Thus, we suggest a new inventory of contrastive connective functions and discuss their relationship to contrastive coherence relations that have been proposed in earlier work.}, language = {en} } @article{TiwariPrakashGrossetal.2020, author = {Tiwari, Abhishek and Prakash, Jyoti and Groß, Sascha and Hammer, Christian}, title = {A large scale analysis of Android}, series = {The journal of systems and software}, volume = {170}, journal = {The journal of systems and software}, publisher = {Elsevier}, address = {New York}, issn = {0164-1212}, doi = {10.1016/j.jss.2020.110775}, pages = {17}, year = {2020}, abstract = {Many Android applications embed webpages via WebView components and execute JavaScript code within Android. Hybrid applications leverage dedicated APIs to load a resource and render it in a WebView. Furthermore, Android objects can be shared with the JavaScript world. However, bridging the interfaces of the Android and JavaScript world might also incur severe security threats: Potentially untrusted webpages and their JavaScript might interfere with the Android environment and its access to native features. No general analysis is currently available to assess the implications of such hybrid apps bridging the two worlds. To understand the semantics and effects of hybrid apps, we perform a large-scale study on the usage of the hybridization APIs in the wild. We analyze and categorize the parameters to hybridization APIs for 7,500 randomly selected and the 196 most popular applications from the Google Playstore as well as 1000 malware samples. Our results advance the general understanding of hybrid applications, as well as implications for potential program analyses, and the current security situation: We discovered thousands of flows of sensitive data from Android to JavaScript, the vast majority of which could flow to potentially untrustworthy code. Our analysis identified numerous web pages embedding vulnerabilities, which we exemplarily exploited. Additionally, we discovered a multitude of applications in which potentially untrusted JavaScript code may interfere with (trusted) Android objects, both in benign and malign applications.}, language = {en} } @article{BordihnVaszil2020, author = {Bordihn, Henning and Vaszil, Gy{\"o}rgy}, title = {Deterministic Lindenmayer systems with dynamic control of parallelism}, series = {International journal of foundations of computer science}, volume = {31}, journal = {International journal of foundations of computer science}, number = {1}, publisher = {World Scientific}, address = {Singapore}, issn = {0129-0541}, doi = {10.1142/S0129054120400031}, pages = {37 -- 51}, year = {2020}, abstract = {M-rate 0L systems are interactionless Lindenmayer systems together with a function assigning to every string a set of multisets of productions that may be applied simultaneously to the string. Some questions that have been left open in the forerunner papers are examined, and the computational power of deterministic M-rate 0L systems is investigated, where also tabled and extended variants are taken into consideration.}, language = {en} } @misc{HollmannFrohmeEndrullatetal.2020, author = {Hollmann, Susanne and Frohme, Marcus and Endrullat, Christoph and Kremer, Andreas and D'Elia, Domenica and Regierer, Babette and Nechyporenko, Alina}, title = {Ten simple rules on how to write a standard operating procedure}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {9}, issn = {1866-8372}, doi = {10.25932/publishup-52587}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-525877}, pages = {12}, year = {2020}, abstract = {Research publications and data nowadays should be publicly available on the internet and, theoretically, usable for everyone to develop further research, products, or services. The long-term accessibility of research data is, therefore, fundamental in the economy of the research production process. However, the availability of data is not sufficient by itself, but also their quality must be verifiable. Measures to ensure reuse and reproducibility need to include the entire research life cycle, from the experimental design to the generation of data, quality control, statistical analysis, interpretation, and validation of the results. Hence, high-quality records, particularly for providing a string of documents for the verifiable origin of data, are essential elements that can act as a certificate for potential users (customers). These records also improve the traceability and transparency of data and processes, therefore, improving the reliability of results. Standards for data acquisition, analysis, and documentation have been fostered in the last decade driven by grassroot initiatives of researchers and organizations such as the Research Data Alliance (RDA). Nevertheless, what is still largely missing in the life science academic research are agreed procedures for complex routine research workflows. Here, well-crafted documentation like standard operating procedures (SOPs) offer clear direction and instructions specifically designed to avoid deviations as an absolute necessity for reproducibility. Therefore, this paper provides a standardized workflow that explains step by step how to write an SOP to be used as a starting point for appropriate research documentation.}, language = {en} } @article{BordihnMitrana2020, author = {Bordihn, Henning and Mitrana, Victor}, title = {On the degrees of non-regularity and non-context-freeness}, series = {Journal of computer and system sciences}, volume = {108}, journal = {Journal of computer and system sciences}, publisher = {Elsevier}, address = {San Diego, Calif. [u.a.]}, issn = {0022-0000}, doi = {10.1016/j.jcss.2019.09.003}, pages = {104 -- 117}, year = {2020}, abstract = {We study the derivational complexity of context-free and context-sensitive grammars by counting the maximal number of non-regular and non-context-free rules used in a derivation, respectively. The degree of non-regularity/non-context-freeness of a language is the minimum degree of non-regularity/non-context-freeness of context-free/context-sensitive grammars generating it. A language has finite degree of non-regularity iff it is regular. We give a condition for deciding whether the degree of non-regularity of a given unambiguous context-free grammar is finite. The problem becomes undecidable for arbitrary linear context-free grammars. The degree of non-regularity of unambiguous context-free grammars generating non-regular languages as well as that of grammars generating deterministic context-free languages that are not regular is of order Omega(n). Context-free non-regular languages of sublinear degree of non-regularity are presented. A language has finite degree of non-context-freeness if it is context-free. Context-sensitive grammars with a quadratic degree of non-context-freeness are more powerful than those of a linear degree.}, language = {en} } @article{GebserJanhunenRintanen2020, author = {Gebser, Martin and Janhunen, Tomi and Rintanen, Jussi}, title = {Declarative encodings of acyclicity properties}, series = {Journal of logic and computation}, volume = {30}, journal = {Journal of logic and computation}, number = {4}, publisher = {Oxford Univ. Press}, address = {Eynsham, Oxford}, issn = {0955-792X}, doi = {10.1093/logcom/exv063}, pages = {923 -- 952}, year = {2020}, abstract = {Many knowledge representation tasks involve trees or similar structures as abstract datatypes. However, devising compact and efficient declarative representations of such structural properties is non-obvious and can be challenging indeed. In this article, we take a number of acyclicity properties into consideration and investigate various logic-based approaches to encode them. We use answer set programming as the primary representation language but also consider mappings to related formalisms, such as propositional logic, difference logic and linear programming. We study the compactness of encodings and the resulting computational performance on benchmarks involving acyclic or tree structures.}, language = {en} } @misc{XenikoudakisAhmedHarrisetal.2020, author = {Xenikoudakis, Georgios and Ahmed, Mayeesha and Harris, Jacob Colt and Wadleigh, Rachel and Paijmans, Johanna L. A. and Hartmann, Stefanie and Barlow, Axel and Lerner, Heather and Hofreiter, Michael}, title = {Ancient DNA reveals twenty million years of aquatic life in beavers}, series = {Current biology : CB}, volume = {30}, journal = {Current biology : CB}, number = {3}, publisher = {Current Biology Ltd.}, address = {London}, issn = {0960-9822}, doi = {10.1016/j.cub.2019.12.041}, pages = {R110 -- R111}, year = {2020}, abstract = {Xenikoudakis et al. report a partial mitochondrial genome of the extinct giant beaver Castoroides and estimate the origin of aquatic behavior in beavers to approximately 20 million years. This time estimate coincides with the extinction of terrestrial beavers and raises the question whether the two events had a common cause.}, language = {en} } @article{GebserMarateaRicca2020, author = {Gebser, Martin and Maratea, Marco and Ricca, Francesco}, title = {The Seventh Answer Set Programming Competition}, series = {Theory and practice of logic programming}, volume = {20}, journal = {Theory and practice of logic programming}, number = {2}, publisher = {Cambridge Univ. Press}, address = {Cambridge [u.a.]}, issn = {1471-0684}, doi = {10.1017/S1471068419000061}, pages = {176 -- 204}, year = {2020}, abstract = {Answer Set Programming (ASP) is a prominent knowledge representation language with roots in logic programming and non-monotonic reasoning. Biennial ASP competitions are organized in order to furnish challenging benchmark collections and assess the advancement of the state of the art in ASP solving. In this paper, we report on the design and results of the Seventh ASP Competition, jointly organized by the University of Calabria (Italy), the University of Genova (Italy), and the University of Potsdam (Germany), in affiliation with the 14th International Conference on Logic Programming and Non-Monotonic Reasoning (LPNMR 2017).}, language = {en} } @misc{SahlmannClemensNowaketal.2020, author = {Sahlmann, Kristina and Clemens, Vera and Nowak, Michael and Schnor, Bettina}, title = {MUP}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1094}, issn = {1866-8372}, doi = {10.25932/publishup-48901}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-489013}, pages = {23}, year = {2020}, abstract = {Message Queuing Telemetry Transport (MQTT) is one of the dominating protocols for edge- and cloud-based Internet of Things (IoT) solutions. When a security vulnerability of an IoT device is known, it has to be fixed as soon as possible. This requires a firmware update procedure. In this paper, we propose a secure update protocol for MQTT-connected devices which ensures the freshness of the firmware, authenticates the new firmware and considers constrained devices. We show that the update protocol is easy to integrate in an MQTT-based IoT network using a semantic approach. The feasibility of our approach is demonstrated by a detailed performance analysis of our prototype implementation on a IoT device with 32 kB RAM. Thereby, we identify design issues in MQTT 5 which can help to improve the support of constrained devices.}, language = {en} } @article{SahlmannClemensNowaketal.2020, author = {Sahlmann, Kristina and Clemens, Vera and Nowak, Michael and Schnor, Bettina}, title = {MUP}, series = {Sensors}, volume = {21}, journal = {Sensors}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s21010010}, pages = {21}, year = {2020}, abstract = {Message Queuing Telemetry Transport (MQTT) is one of the dominating protocols for edge- and cloud-based Internet of Things (IoT) solutions. When a security vulnerability of an IoT device is known, it has to be fixed as soon as possible. This requires a firmware update procedure. In this paper, we propose a secure update protocol for MQTT-connected devices which ensures the freshness of the firmware, authenticates the new firmware and considers constrained devices. We show that the update protocol is easy to integrate in an MQTT-based IoT network using a semantic approach. The feasibility of our approach is demonstrated by a detailed performance analysis of our prototype implementation on a IoT device with 32 kB RAM. Thereby, we identify design issues in MQTT 5 which can help to improve the support of constrained devices.}, language = {en} } @article{BordihnMitranaPaunetal.2020, author = {Bordihn, Henning and Mitrana, Victor and Paun, Andrei and Paun, Mihaela}, title = {Hairpin completions and reductions}, series = {Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal}, volume = {20}, journal = {Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal}, number = {2}, publisher = {Springer Science + Business Media B.V.}, address = {Dordrecht}, issn = {1572-9796}, doi = {10.1007/s11047-020-09797-0}, pages = {193 -- 203}, year = {2020}, abstract = {This paper is part of the investigation of some operations on words and languages with motivations coming from DNA biochemistry, namely three variants of hairpin completion and three variants of hairpin reduction. Since not all the hairpin completions or reductions of semilinear languages remain semilinear, we study sufficient conditions for semilinear languages to preserve their semilinearity property after applying the non-iterated hairpin completion or hairpin reduction. A similar approach is then applied to the iterated variants of these operations. Along these lines, we define the hairpin reduction root of a language and show that the hairpin reduction root of a semilinear language is not necessarily semilinear except the universal language. A few open problems are finally discussed.}, language = {en} } @article{SchneiderBrickDziobek2020, author = {Schneider, Jan Niklas and Brick, Timothy R. and Dziobek, Isabel}, title = {Distance to the neutral face predicts arousal ratings of dynamic facial expressions in individuals with and without Autism Spectrum Disorder}, series = {Frontiers in psychology}, volume = {11}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2020.577494}, pages = {15}, year = {2020}, abstract = {Arousal is one of the dimensions of core affect and frequently used to describe experienced or observed emotional states. While arousal ratings of facial expressions are collected in many studies it is not well understood how arousal is displayed in or interpreted from facial expressions. In the context of socioemotional disorders such as Autism Spectrum Disorder, this poses the question of a differential use of facial information for arousal perception. In this study, we demonstrate how automated face-tracking tools can be used to extract predictors of arousal judgments. We find moderate to strong correlations among all measures of static information on one hand and all measures of dynamic information on the other. Based on these results, we tested two measures, average distance to the neutral face and average facial movement speed, within and between neurotypical individuals (N = 401) and individuals with autism (N = 19). Distance to the neutral face was predictive of arousal in both groups. Lower mean arousal ratings were found for the autistic group, but no difference in correlation of the measures and arousal ratings could be found between groups. Results were replicated in an high autistic traits group. The findings suggest a qualitatively similar perception of arousal for individuals with and without autism. No correlations between valence ratings and any of the measures could be found, emphasizing the specificity of our tested measures. Distance and speed predictors share variability and thus speed should not be discarded as a predictor of arousal ratings.}, language = {en} } @article{LutherTiberiusBrem2020, author = {Luther, Laura and Tiberius, Victor and Brem, Alexander}, title = {User experience (UX) in business, management, and psychology}, series = {Multimodal technologies and interaction : open access journal}, volume = {4}, journal = {Multimodal technologies and interaction : open access journal}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2414-4088}, doi = {10.3390/mti4020018}, pages = {19}, year = {2020}, abstract = {User Experience (UX) describes the holistic experience of a user before, during, and after interaction with a platform, product, or service. UX adds value and attraction to their sole functionality and is therefore highly relevant for firms. The increased interest in UX has produced a vast amount of scholarly research since 1983. The research field is, therefore, complex and scattered. Conducting a bibliometric analysis, we aim at structuring the field quantitatively and rather abstractly. We employed citation analyses, co-citation analyses, and content analyses to evaluate productivity and impact of extant research. We suggest that future research should focus more on business and management related topics.}, language = {en} } @article{LuckeHaferHartmann2020, author = {Lucke, Ulrike and Hafer, J{\"o}rg and Hartmann, Niklas}, title = {Strategieentwicklung in der Hochschule als partizipativer Prozess}, series = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, journal = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, number = {6}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-498-2}, issn = {2192-1075}, doi = {10.25932/publishup-49276}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-492764}, pages = {99 -- 117}, year = {2020}, abstract = {Die Setzung strategischer Ziele sowie die Zuordnung und Umsetzung dazugeh{\"o}render Maßnahmen sind ein wesentliches Element, um die Innovationsf{\"a}higkeit von Organisationen zu erhalten. In den vergangenen Jahren ist auch an Hochschulen die Strategiebildung deutlich vorangetrieben worden. Dies betrifft verschiedene Handlungsfelder, und es werden verschiedene Ans{\"a}tze verfolgt. Der vorliegende Beitrag greift am Beispiel der Universit{\"a}t Potsdam drei in den vergangenen Jahren adressierte Strategiebereiche heraus: IT, E-Learning und Forschungsdaten. Die damit verbundenen Prozesse waren in unterschiedlichem Maß von Partizipation gepr{\"a}gt. Die gesammelten Erfahrungen werden reflektiert, und es werden Empfehlungen f{\"u}r Strategieentwicklungsprozesse abgeleitet.}, language = {de} } @article{HempelAdolphsLandwehretal.2020, author = {Hempel, Sabrina and Adolphs, Julian and Landwehr, Niels and Willink, Dilya and Janke, David and Amon, Thomas}, title = {Supervised machine learning to assess methane emissions of a dairy building with natural ventilation}, series = {Applied Sciences}, volume = {10}, journal = {Applied Sciences}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app10196938}, pages = {21}, year = {2020}, abstract = {A reliable quantification of greenhouse gas emissions is a basis for the development of adequate mitigation measures. Protocols for emission measurements and data analysis approaches to extrapolate to accurate annual emission values are a substantial prerequisite in this context. We systematically analyzed the benefit of supervised machine learning methods to project methane emissions from a naturally ventilated cattle building with a concrete solid floor and manure scraper located in Northern Germany. We took into account approximately 40 weeks of hourly emission measurements and compared model predictions using eight regression approaches, 27 different sampling scenarios and four measures of model accuracy. Data normalization was applied based on median and quartile range. A correlation analysis was performed to evaluate the influence of individual features. This indicated only a very weak linear relation between the methane emission and features that are typically used to predict methane emission values of naturally ventilated barns. It further highlighted the added value of including day-time and squared ambient temperature as features. The error of the predicted emission values was in general below 10\%. The results from Gaussian processes, ordinary multilinear regression and neural networks were least robust. More robust results were obtained with multilinear regression with regularization, support vector machines and particularly the ensemble methods gradient boosting and random forest. The latter had the added value to be rather insensitive against the normalization procedure. In the case of multilinear regression, also the removal of not significantly linearly related variables (i.e., keeping only the day-time component) led to robust modeling results. We concluded that measurement protocols with 7 days and six measurement periods can be considered sufficient to model methane emissions from the dairy barn with solid floor with manure scraper, particularly when periods are distributed over the year with a preference for transition periods. Features should be normalized according to median and quartile range and must be carefully selected depending on the modeling approach.}, language = {en} } @article{StrickrothKiy2020, author = {Strickroth, Sven and Kiy, Alexander}, title = {E-Assessment etablieren}, series = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, journal = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, number = {6}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-498-2}, issn = {2192-1075}, doi = {10.25932/publishup-49303}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-493036}, pages = {257 -- 272}, year = {2020}, abstract = {Elektronische Lernstandserhebungen, sogenannte E-Assessments, bieten f{\"u}r Lehrende und Studierende viele Vorteile z. B. hinsichtlich schneller R{\"u}ckmeldungen oder kompetenzorientierter Fragenformate, und erm{\"o}glichen es, unabh{\"a}ngig von Ort und Zeit Pr{\"u}fungen zu absolvieren. In diesem Beitrag werden die Einf{\"u}hrung von summativen Lernstandserhebungen, sogenannter E-Klausuren, am Beispiel der Universit{\"a}t Potsdam, der Aufbau einer l{\"a}nder{\"u}bergreifenden Initiative f{\"u}r E-Assessment sowie technische M{\"o}glichkeiten f{\"u}r dezentrale elektronische Klausuren vorgestellt. Dabei werden der aktuelle Stand, die Ziele und die gew{\"a}hlte stufenweise Umsetzungsstrategie der Universit{\"a}t Potsdam skizziert. Darauf aufbauend folgt eine Beschreibung des Vorgehens, der Kooperationsm{\"o}glichkeiten f{\"u}r den Wissens- und Erfahrungsaustausch sowie Herausforderungen der E-Assessment- Initiative. Abschließend werden verschiedene E-Klausurformen und technische M{\"o}glichkeiten zur Umsetzung komplexer Pr{\"u}fungsumgebungen klassifiziert sowie mit ihren charakteristischen Vor- und Nachteilen diskutiert und eine integrierte L{\"o}sung vorgeschlagen.}, language = {de} } @article{LuckeStrickroth2020, author = {Lucke, Ulrike and Strickroth, Sven}, title = {Digitalisierung in Lehre und Studium}, series = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, journal = {Potsdamer Beitr{\"a}ge zur Hochschulforschung}, number = {6}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-498-2}, issn = {2192-1075}, doi = {10.25932/publishup-49302}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-493024}, pages = {235 -- 255}, year = {2020}, abstract = {Das gr{\"o}ßte der f{\"a}cher{\"u}bergreifenden Projekte im Potsdamer Projekt Qualit{\"a}tspakt Lehre hatte die fl{\"a}chendeckende Etablierung von digitalen Medien als einen integralen Bestandteil von Lehre und Studium zum Gegenstand. Im Teilprojekt E-Learning in Studienbereichen (eLiS) wurden daf{\"u}r Maßnahmen in den Feldern Organisations-, technische und Inhaltsentwicklung zusammengef{\"u}hrt. Der vorliegende Beitrag pr{\"a}sentiert auf Basis von Ausgangslage und Zielsetzungen die Ergebnisse rund um die Digitalisierung von Lehre und Studium an der Universit{\"a}t Potsdam. Exemplarisch werden f{\"u}nf Dienste n{\"a}her vorgestellt, die inzwischen gr{\"o}ßtenteils in den Regelbetrieb der Hochschule {\"u}bergegangen sind: die Videoplattform Media.UP, die mobile App Reflect.UP, die pers{\"o}nliche Lernumgebung Campus. UP, das Self-Service-Portal Cook.UP und das Anzeigesystem Freiraum.UP. Dabei wird jeweils ein technischer Blick „unter die Haube" verbunden mit einer Erl{\"a}uterung der Nutzungsm{\"o}glichkeiten, denen eine aktuelle Einsch{\"a}tzung von Lehrenden und Studierenden der Hochschule gegen{\"u}bergestellt wird. Der Beitrag schließt mit einer Einbettung der vorgestellten Entwicklungen in einen gr{\"o}ßeren Kontext und einem Ausblick auf die weiterhin anstehenden Aufgaben.}, language = {de} } @article{DugWeidlingSogomonyanetal.2020, author = {Dug, Mehmed and Weidling, Stefan and Sogomonyan, Egor and Jokic, Dejan and Krstić, Miloš}, title = {Full error detection and correction method applied on pipelined structure using two approaches}, series = {Journal of circuits, systems and computers}, volume = {29}, journal = {Journal of circuits, systems and computers}, number = {13}, publisher = {World Scientific}, address = {Singapore}, issn = {0218-1266}, doi = {10.1142/S0218126620502187}, pages = {15}, year = {2020}, abstract = {In this paper, two approaches are evaluated using the Full Error Detection and Correction (FEDC) method for a pipelined structure. The approaches are referred to as Full Duplication with Comparison (FDC) and Concurrent Checking with Parity Prediction (CCPP). Aforementioned approaches are focused on the borderline cases of FEDC method which implement Error Detection Circuit (EDC) in two manners for the purpose of protection of combinational logic to address the soft errors of unspecified duration. The FDC approach implements a full duplication of the combinational circuit, as the most complex and expensive implementation of the FEDC method, and the CCPP approach implements only the parity prediction bit, being the simplest and cheapest technique, for soft error detection. Both approaches are capable of detecting soft errors in the combinational logic, with single faults being injected into the design. On the one hand, the FDC approach managed to detect and correct all injected faults while the CCPP approach could not detect multiple faults created at the output of combinational circuit. On the other hand, the FDC approach leads to higher power consumption and area increase compared to the CCPP approach.}, language = {en} } @article{LiBreitenreiterAndjelkovicetal.2020, author = {Li, Yuanqing and Breitenreiter, Anselm and Andjelkovic, Marko and Chen, Junchao and Babic, Milan and Krstić, Miloš}, title = {Double cell upsets mitigation through triple modular redundancy}, series = {Microelectronics Journal}, volume = {96}, journal = {Microelectronics Journal}, publisher = {Elsevier}, address = {Oxford}, issn = {0026-2692}, doi = {10.1016/j.mejo.2019.104683}, pages = {8}, year = {2020}, abstract = {A triple modular redundancy (TMR) based design technique for double cell upsets (DCUs) mitigation is investigated in this paper. This technique adds three extra self-voter circuits into a traditional TMR structure to enable the enhanced error correction capability. Fault-injection simulations show that the soft error rate (SER) of the proposed technique is lower than 3\% of that of TMR. The implementation of this proposed technique is compatible with the automatic digital design flow, and its applicability and performance are evaluated on an FIFO circuit.}, language = {en} } @article{CabalarDieguezSchaubetal.2020, author = {Cabalar, Pedro and Dieguez, Martin and Schaub, Torsten and Schuhmann, Anna}, title = {Towards metric temporal answer set programming}, series = {Theory and practice of logic programming}, volume = {20}, journal = {Theory and practice of logic programming}, number = {5}, publisher = {Cambridge Univ. Press}, address = {Cambridge [u.a.]}, issn = {1471-0684}, doi = {10.1017/S1471068420000307}, pages = {783 -- 798}, year = {2020}, abstract = {We elaborate upon the theoretical foundations of a metric temporal extension of Answer Set Programming. In analogy to previous extensions of ASP with constructs from Linear Temporal and Dynamic Logic, we accomplish this in the setting of the logic of Here-and-There and its non-monotonic extension, called Equilibrium Logic. More precisely, we develop our logic on the same semantic underpinnings as its predecessors and thus use a simple time domain of bounded time steps. This allows us to compare all variants in a uniform framework and ultimately combine them in a common implementation.}, language = {en} } @article{CabalarFandinoGareaetal.2020, author = {Cabalar, Pedro and Fandi{\~n}o, Jorge and Garea, Javier and Romero, Javier and Schaub, Torsten}, title = {Eclingo}, series = {Theory and practice of logic programming}, volume = {20}, journal = {Theory and practice of logic programming}, number = {6}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068420000228}, pages = {834 -- 847}, year = {2020}, abstract = {We describe eclingo, a solver for epistemic logic programs under Gelfond 1991 semantics built upon the Answer Set Programming system clingo. The input language of eclingo uses the syntax extension capabilities of clingo to define subjective literals that, as usual in epistemic logic programs, allow for checking the truth of a regular literal in all or in some of the answer sets of a program. The eclingo solving process follows a guess and check strategy. It first generates potential truth values for subjective literals and, in a second step, it checks the obtained result with respect to the cautious and brave consequences of the program. This process is implemented using the multi-shot functionalities of clingo. We have also implemented some optimisations, aiming at reducing the search space and, therefore, increasing eclingo 's efficiency in some scenarios. Finally, we compare the efficiency of eclingo with two state-of-the-art solvers for epistemic logic programs on a pair of benchmark scenarios and show that eclingo generally outperforms their obtained results.}, language = {en} } @article{FandinoLifschitzLuehneetal.2020, author = {Fandi{\~n}o, Jorge and Lifschitz, Vladimir and L{\"u}hne, Patrick and Schaub, Torsten}, title = {Verifying tight logic programs with Anthem and Vampire}, series = {Theory and practice of logic programming}, volume = {20}, journal = {Theory and practice of logic programming}, number = {5}, publisher = {Cambridge Univ. Press}, address = {Cambridge [u.a.]}, issn = {1471-0684}, doi = {10.1017/S1471068420000344}, pages = {735 -- 750}, year = {2020}, abstract = {This paper continues the line of research aimed at investigating the relationship between logic programs and first-order theories. We extend the definition of program completion to programs with input and output in a subset of the input language of the ASP grounder gringo, study the relationship between stable models and completion in this context, and describe preliminary experiments with the use of two software tools, anthem and vampire, for verifying the correctness of programs with input and output. Proofs of theorems are based on a lemma that relates the semantics of programs studied in this paper to stable models of first-order formulas.}, language = {en} } @phdthesis{Nordmann2020, author = {Nordmann, Paul-Patrick}, title = {Fehlerkorrektur von Speicherfehlern mit Low-Density-Parity-Check-Codes}, doi = {10.25932/publishup-48048}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-480480}, school = {Universit{\"a}t Potsdam}, pages = {IV, 99, XII}, year = {2020}, abstract = {Die Fehlerkorrektur in der Codierungstheorie besch{\"a}ftigt sich mit der Erkennung und Behebung von Fehlern bei der {\"U}bertragung und auch Sicherung von Nachrichten. Hierbei wird die Nachricht durch zus{\"a}tzliche Informationen in ein Codewort kodiert. Diese Kodierungsverfahren besitzen verschiedene Anspr{\"u}che, wie zum Beispiel die maximale Anzahl der zu korrigierenden Fehler und die Geschwindigkeit der Korrektur. Ein g{\"a}ngiges Codierungsverfahren ist der BCH-Code, welches industriell f{\"u}r bis zu vier Fehler korrigiere Codes Verwendung findet. Ein Nachteil dieser Codes ist die technische Durchlaufzeit f{\"u}r die Berechnung der Fehlerstellen mit zunehmender Codel{\"a}nge. Die Dissertation stellt ein neues Codierungsverfahren vor, bei dem durch spezielle Anordnung kleinere Codel{\"a}ngen eines BCH-Codes ein langer Code erzeugt wird. Diese Anordnung geschieht {\"u}ber einen weiteren speziellen Code, einem LDPC-Code, welcher f{\"u}r eine schneller Fehlererkennung konzipiert ist. Hierf{\"u}r wird ein neues Konstruktionsverfahren vorgestellt, welches einen Code f{\"u}r einen beliebige L{\"a}nge mit vorgebbaren beliebigen Anzahl der zu korrigierenden Fehler vorgibt. Das vorgestellte Konstruktionsverfahren erzeugt zus{\"a}tzlich zum schnellen Verfahren der Fehlererkennung auch eine leicht und schnelle Ableitung eines Verfahrens zu Kodierung der Nachricht zum Codewort. Dies ist in der Literatur f{\"u}r die LDPC-Codes bis zum jetzigen Zeitpunkt einmalig. Durch die Konstruktion eines LDPC-Codes wird ein Verfahren vorgestellt wie dies mit einem BCH-Code kombiniert wird, wodurch eine Anordnung des BCH-Codes in Bl{\"o}cken erzeugt wird. Neben der allgemeinen Beschreibung dieses Codes, wird ein konkreter Code f{\"u}r eine 2-Bitfehlerkorrektur beschrieben. Diese besteht aus zwei Teilen, welche in verschiedene Varianten beschrieben und verglichen werden. F{\"u}r bestimmte L{\"a}ngen des BCH-Codes wird ein Problem bei der Korrektur aufgezeigt, welche einer algebraischen Regel folgt. Der BCH-Code wird sehr allgemein beschrieben, doch existiert durch bestimmte Voraussetzungen ein BCH-Code im engerem Sinne, welcher den Standard vorgibt. Dieser BCH-Code im engerem Sinne wird in dieser Dissertation modifiziert, so dass das algebraische Problem bei der 2-Bitfehler Korrektur bei der Kombination mit dem LDPC-Code nicht mehr existiert. Es wird gezeigt, dass nach der Modifikation der neue Code weiterhin ein BCH-Code im allgemeinen Sinne ist, welcher 2-Bitfehler korrigieren und 3-Bitfehler erkennen kann. Bei der technischen Umsetzung der Fehlerkorrektur wird des Weiteren gezeigt, dass die Durchlaufzeiten des modifizierten Codes im Vergleich zum BCH-Code schneller ist und weiteres Potential f{\"u}r Verbesserungen besitzt. Im letzten Kapitel wird gezeigt, dass sich dieser modifizierte Code mit beliebiger L{\"a}nge eignet f{\"u}r die Kombination mit dem LDPC-Code, wodurch dieses Verfahren nicht nur umf{\"a}nglicher in der L{\"a}nge zu nutzen ist, sondern auch durch die schnellere Dekodierung auch weitere Vorteile gegen{\"u}ber einem BCH-Code im engerem Sinne besitzt.}, language = {de} } @article{KuentzerKrstić2020, author = {Kuentzer, Felipe A. and Krstić, Miloš}, title = {Soft error detection and correction architecture for asynchronous bundled data designs}, series = {IEEE transactions on circuits and systems}, volume = {67}, journal = {IEEE transactions on circuits and systems}, number = {12}, publisher = {Institute of Electrical and Electronics Engineers}, address = {New York}, issn = {1549-8328}, doi = {10.1109/TCSI.2020.2998911}, pages = {4883 -- 4894}, year = {2020}, abstract = {In this paper, an asynchronous design for soft error detection and correction in combinational and sequential circuits is presented. The proposed architecture is called Asynchronous Full Error Detection and Correction (AFEDC). A custom design flow with integrated commercial EDA tools generates the AFEDC using the asynchronous bundled-data design style. The AFEDC relies on an Error Detection Circuit (EDC) for protecting the combinational logic and fault-tolerant latches for protecting the sequential logic. The EDC can be implemented using different detection methods. For this work, two boundary variants are considered, the Full Duplication with Comparison (FDC) and the Partial Duplication with Parity Prediction (PDPP). The AFEDC architecture can handle single events and timing faults of arbitrarily long duration as well as the synchronous FEDC, but additionally can address known metastability issues of the FEDC and other similar synchronous architectures and provide a more practical solution for handling the error recovery process. Two case studies are developed, a carry look-ahead adder and a pipelined non-restoring array divider. Results show that the AFEDC provides equivalent fault coverage when compared to the FEDC while reducing area, ranging from 9.6\% to 17.6\%, and increasing energy efficiency, which can be up to 6.5\%.}, language = {en} } @incollection{HaferKostaedtLucke2021, author = {Hafer, J{\"o}rg and Kost{\"a}dt, Peter and Lucke, Ulrike}, title = {Das Corona-Virus als Treiber der Digitalisierung}, series = {Das Corona-Virus als Treiber der Digitalisierung}, booktitle = {Das Corona-Virus als Treiber der Digitalisierung}, publisher = {Springer}, address = {Wiesbaden}, isbn = {978-3-658-32608-1}, doi = {10.1007/978-3-658-32609-8_15}, pages = {219 -- 242}, year = {2021}, abstract = {Mit der Covid-19-Pandemie hat die Digitalisierung an Hochschulen weitere Bedeutung erlangt. Insbesondere dem Einsatz digitaler Medien in Lehre und Studium galt großes Augenmerk. Das legt die Hoffnung nahe, dass die Digitalisierung durch das Virus einen Schub erfahren und die Hochschulen dauerhaft ver{\"a}ndert hat. Der Beitrag geht am Beispiel der Universit{\"a}t Potsdam der Frage nach, welcher Natur diese Ver{\"a}nderungen waren - ausgehend sowohl von den unternommenen Maßnahmen als auch von den erzielten Resultaten - und inwiefern sie von Dauer sind. Dabei werden f{\"o}rderliche und hemmende Faktoren identifiziert, die in Empfehlungen f{\"u}r weitere Digitalisierungsvorhaben {\"u}bersetzt werden.}, language = {de} } @phdthesis{Moebert2021, author = {Moebert, Tobias}, title = {Zum Einfluss von Adaptivit{\"a}t auf die Wahrnehmung von Komplexit{\"a}t in der Mensch-Technik-Interaktion}, doi = {10.25932/publishup-49992}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-499926}, school = {Universit{\"a}t Potsdam}, pages = {449}, year = {2021}, abstract = {Wir leben in einer Gesellschaft, die von einem stetigen Wunsch nach Innovation und Fortschritt gepr{\"a}gt ist. Folgen dieses Wunsches sind die immer weiter fortschreitende Digitalisierung und informatische Vernetzung aller Lebensbereiche, die so zu immer komplexeren sozio-technischen Systemen f{\"u}hren. Ziele dieser Systeme sind u. a. die Unterst{\"u}tzung von Menschen, die Verbesserung ihrer Lebenssituation oder Lebensqualit{\"a}t oder die Erweiterung menschlicher M{\"o}glichkeiten. Doch haben neue komplexe technische Systeme nicht nur positive soziale und gesellschaftliche Effekte. Oft gibt es unerw{\"u}nschte Nebeneffekte, die erst im Gebrauch sichtbar werden, und sowohl Konstrukteur*innen als auch Nutzer*innen komplexer vernetzter Technologien f{\"u}hlen sich oft orientierungslos. Die Folgen k{\"o}nnen von sinkender Akzeptanz bis hin zum kompletten Verlust des Vertrauens in vernetze Softwaresysteme reichen. Da komplexe Anwendungen, und damit auch immer komplexere Mensch-Technik-Interaktionen, immer mehr an Relevanz gewinnen, ist es umso wichtiger, wieder Orientierung zu finden. Dazu m{\"u}ssen wir zuerst diejenigen Elemente identifizieren, die in der Interaktion mit vernetzten sozio-technischen Systemen zu Komplexit{\"a}t beitragen und somit Orientierungsbedarf hervorrufen. Mit dieser Arbeit soll ein Beitrag geleistet werden, um ein strukturiertes Reflektieren {\"u}ber die Komplexit{\"a}t vernetzter sozio-technischer Systeme im gesamten Konstruktionsprozess zu erm{\"o}glichen. Dazu wird zuerst eine Definition von Komplexit{\"a}t und komplexen Systemen erarbeitet, die {\"u}ber das informatische Verst{\"a}ndnis von Komplexit{\"a}t (also der Kompliziertheit von Problemen, Algorithmen oder Daten) hinausgeht. Im Vordergrund soll vielmehr die sozio-technische Interaktion mit und in komplexen vernetzten Systemen stehen. Basierend auf dieser Definition wird dann ein Analysewerkzeug entwickelt, welches es erm{\"o}glicht, die Komplexit{\"a}t in der Interaktion mit sozio-technischen Systemen sichtbar und beschreibbar zu machen. Ein Bereich, in dem vernetzte sozio-technische Systeme zunehmenden Einzug finden, ist jener digitaler Bildungstechnologien. Besonders adaptiven Bildungstechnologien wurde in den letzten Jahrzehnten ein großes Potential zugeschrieben. Zwei adaptive Lehr- bzw. Trainingssysteme sollen deshalb exemplarisch mit dem in dieser Arbeit entwickelten Analysewerkzeug untersucht werden. Hierbei wird ein besonderes Augenmerkt auf den Einfluss von Adaptivit{\"a}t auf die Komplexit{\"a}t von Mensch-Technik-Interaktionssituationen gelegt. In empirischen Untersuchungen werden die Erfahrungen von Konstrukteur*innen und Nutzer*innen jener adaptiver Systeme untersucht, um so die entscheidenden Kriterien f{\"u}r Komplexit{\"a}t ermitteln zu k{\"o}nnen. Auf diese Weise k{\"o}nnen zum einen wiederkehrende Orientierungsfragen bei der Entwicklung adaptiver Bildungstechnologien aufgedeckt werden. Zum anderen werden als komplex wahrgenommene Interaktionssituationen identifiziert. An diesen Situationen kann gezeigt werden, wo aufgrund der Komplexit{\"a}t des Systems die etablierten Alltagsroutinen von Nutzenden nicht mehr ausreichen, um die Folgen der Interaktion mit dem System vollst{\"a}ndig erfassen zu k{\"o}nnen. Dieses Wissen kann sowohl Konstrukteur*innen als auch Nutzer*innen helfen, in Zukunft besser mit der inh{\"a}renten Komplexit{\"a}t moderner Bildungstechnologien umzugehen.}, language = {de} } @phdthesis{Dehne2021, author = {Dehne, Julian}, title = {M{\"o}glichkeiten und Limitationen der medialen Unterst{\"u}tzung forschenden Lernens}, doi = {10.25932/publishup-49789}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-497894}, school = {Universit{\"a}t Potsdam}, pages = {xvii, 404}, year = {2021}, abstract = {Forschendes Lernen und die digitale Transformation sind zwei der wichtigsten Einfl{\"u}sse auf die Entwicklung der Hochschuldidaktik im deutschprachigen Raum. W{\"a}hrend das forschende Lernen als normative Theorie das sollen beschreibt, geben die digitalen Werkzeuge, alte wie neue, das k{\"o}nnen in vielen Bereichen vor. In der vorliegenden Arbeit wird ein Prozessmodell aufgestellt, was den Versuch unternimmt, das forschende Lernen hinsichtlich interaktiver, gruppenbasierter Prozesse zu systematisieren. Basierend auf dem entwickelten Modell wurde ein Softwareprototyp implementiert, der den gesamten Forschungsprozess begleiten kann. Dabei werden Gruppenformation, Feedback- und Reflexionsprozesse und das Peer Assessment mit Bildungstechnologien unterst{\"u}tzt. Die Entwicklungen wurden in einem qualitativen Experiment eingesetzt, um Systemwissen {\"u}ber die M{\"o}glichkeiten und Grenzen der digitalen Unterst{\"u}tzung von forschendem Lernen zu gewinnen.}, language = {de} } @article{BordihnVaszil2021, author = {Bordihn, Henning and Vaszil, Gy{\"o}rgy}, title = {Reversible parallel communicating finite automata systems}, series = {Acta informatica}, volume = {58}, journal = {Acta informatica}, number = {4}, publisher = {Springer}, address = {Berlin ; Heidelberg ; New York, NY}, issn = {0001-5903}, doi = {10.1007/s00236-021-00396-9}, pages = {263 -- 279}, year = {2021}, abstract = {We study the concept of reversibility in connection with parallel communicating systems of finite automata (PCFA in short). We define the notion of reversibility in the case of PCFA (also covering the non-deterministic case) and discuss the relationship of the reversibility of the systems and the reversibility of its components. We show that a system can be reversible with non-reversible components, and the other way around, the reversibility of the components does not necessarily imply the reversibility of the system as a whole. We also investigate the computational power of deterministic centralized reversible PCFA. We show that these very simple types of PCFA (returning or non-returning) can recognize regular languages which cannot be accepted by reversible (deterministic) finite automata, and that they can even accept languages that are not context-free. We also separate the deterministic and non-deterministic variants in the case of systems with non-returning communication. We show that there are languages accepted by non-deterministic centralized PCFA, which cannot be recognized by any deterministic variant of the same type.}, language = {en} } @phdthesis{Hitz2021, author = {Hitz, Michael}, title = {Modellierung und Generierung kombinierbarer Benutzungsschnittstellenvarianten und deren gemeinschaftliche Nutzung in Dienst-Ökosystemen}, doi = {10.25932/publishup-50022}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-500224}, school = {Universit{\"a}t Potsdam}, pages = {viii, 313}, year = {2021}, abstract = {Digitalisierung erm{\"o}glicht es uns, mit Partnern (z.B. Unternehmen, Institutionen) in einer IT-unterst{\"u}tzten Umgebung zu interagieren und T{\"a}tigkeiten auszuf{\"u}hren, die vormals manuell erledigt wurden. Ein Ziel der Digitalisierung ist dabei, Dienstleistungen unterschiedlicher fachlicher Dom{\"a}nen zu Prozessen zu kombinieren und vielen Nutzergruppen bedarfsgerecht zug{\"a}nglich zu machen. Hierzu stellen Anbieter technische Dienste bereit, die in unterschiedliche Anwendungen integriert werden k{\"o}nnen. Die Digitalisierung stellt die Anwendungsentwicklung vor neue Herausforderungen. Ein Aspekt ist die bedarfsgerechte Anbindung von Nutzern an Dienste. Zur Interaktion menschlicher Nutzer mit den Diensten werden Benutzungsschnittstellen ben{\"o}tigt, die auf deren Bed{\"u}rfnisse zugeschnitten sind. Hierzu werden Varianten f{\"u}r spezifische Nutzergruppen (fachliche Varianten) und variierende Umgebungen (technische Varianten) ben{\"o}tigt. Zunehmend m{\"u}ssen diese mit Diensten anderer Anbieter kombiniert werden k{\"o}nnen, um dom{\"a}nen{\"u}bergreifend Prozesse zu Anwendungen mit einem erh{\"o}hten Mehrwert f{\"u}r den Endnutzer zu verkn{\"u}pfen (z.B. eine Flugbuchung mit einer optionalen Reiseversicherung). Die Vielf{\"a}ltigkeit der Varianten l{\"a}sst die Erstellung von Benutzungsschnittstellen komplex und die Ergebnisse sehr individuell erscheinen. Daher werden die Varianten in der Praxis vorwiegend manuell erstellt. Dies f{\"u}hrt zur parallelen Entwicklung einer Vielzahl sehr {\"a}hnlicher Anwendungen, die nur geringes Potential zur Wiederverwendung besitzen. Die Folge sind hohe Aufw{\"a}nde bei Erstellung und Wartung. Dadurch wird h{\"a}ufig auf die Unterst{\"u}tzung kleiner Nutzerkreise mit speziellen Anforderungen verzichtet (z.B. Menschen mit physischen Einschr{\"a}nkungen), sodass diese weiterhin von der Digitalisierung ausgeschlossen bleiben. Die Arbeit stellt eine konsistente L{\"o}sung f{\"u}r diese neuen Herausforderungen mit den Mitteln der modellgetriebenen Entwicklung vor. Sie präsentiert einen Ansatz zur Modellierung von Benutzungsschnittstellen, Varianten und Kompositionen und deren automatischer Generierung f{\"u}r digitale Dienste in einem verteilten Umfeld. Die Arbeit schafft eine L{\"o}sung zur Wiederverwendung und gemeinschaftlichen Nutzung von Benutzungsschnittstellen {\"u}ber Anbietergrenzen hinweg. Sie f{\"u}hrt zu einer Infrastruktur, in der eine Vielzahl von Anbietern ihre Expertise in gemeinschaftliche Anwendungen einbringen k{\"o}nnen. Die Beitr{\"a}ge bestehen im Einzelnen in Konzepten und Metamodellen zur Modellierung von Benutzungsschnittstellen, Varianten und Kompositionen sowie einem Verfahren zu deren vollst{\"a}ndig automatisierten Transformation in funktionale Benutzungsschnittstellen. Zur Umsetzung der gemeinschaftlichen Nutzbarkeit werden diese erg{\"a}nzt um eine universelle Repr{\"a}sentation der Modelle, einer Methodik zur Anbindung unterschiedlicher Dienst-Anbieter sowie einer Architektur zur verteilten Nutzung der Artefakte und Verfahren in einer dienstorientierten Umgebung. Der Ansatz bietet die Chance, unterschiedlichste Menschen bedarfsgerecht an der Digitalisierung teilhaben zu lassen. Damit setzt die Arbeit Impulse f{\"u}r zuk{\"u}nftige Methoden zur Anwendungserstellung in einem zunehmend vielf{\"a}ltigen Umfeld.}, language = {de} } @article{BordihnHolzer2021, author = {Bordihn, Henning and Holzer, Markus}, title = {On the number of active states in finite automata}, series = {Acta informatica}, volume = {58}, journal = {Acta informatica}, number = {4}, publisher = {Springer}, address = {Berlin ; Heidelberg [u.a.]}, issn = {0001-5903}, doi = {10.1007/s00236-021-00397-8}, pages = {301 -- 318}, year = {2021}, abstract = {We introduce a new measure of descriptional complexity on finite automata, called the number of active states. Roughly speaking, the number of active states of an automaton A on input w counts the number of different states visited during the most economic computation of the automaton A for the word w. This concept generalizes to finite automata and regular languages in a straightforward way. We show that the number of active states of both finite automata and regular languages is computable, even with respect to nondeterministic finite automata. We further compare the number of active states to related measures for regular languages. In particular, we show incomparability to the radius of regular languages and that the difference between the number of active states and the total number of states needed in finite automata for a regular language can be of exponential order.}, language = {en} } @misc{Reuss2021, type = {Master Thesis}, author = {Reuß, Florian}, title = {Entwicklung eines Prototyps einer Lernumgebung f{\"u}r interaktive Funktionsanalyse-{\"U}bungen nach einem Gamification- Ansatz}, doi = {10.25932/publishup-51904}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-519041}, school = {Universit{\"a}t Potsdam}, pages = {VII, 71}, year = {2021}, abstract = {In vielen Studieng{\"a}ngen kommt es durch die oft heterogenen Vorkenntnisse in der Studieneingangsphase zu mangelnder Motivation durch {\"U}ber- oder Unterforderung. Dieses Problem tritt auch in der musiktheoretischen Grundausbildung an Hochschulen auf. Durch Einsatz von Elementen, die aus dem Unterhaltungskontext gel{\"a}ufig sind, kann eine Steigerung der Motivation erreicht werden. Die Nutzung solcher Elemente wird als Gamification bezeichnet. Das Ziel der vorliegenden Arbeit ist es, am Fallbeispiel der musiktheoretischen Grundausbildung zu analysieren, ob Lerngelegenheiten durch einen gamifizierten interaktiven Prototyp einer Lernumgebung unterst{\"u}tzt werden k{\"o}nnen. Dazu wird die folgende Forschungsfrage gestellt: Inwieweit wirkt Gamification auf die Motivation bei den Lernenden zur Besch{\"a}ftigung mit dem Thema (musikalische) Funktionsanalyse? Um die Forschungsfragen zu beantworten, wurde zun{\"a}chst ein systematisches, theoriegeleitetes Vorgehensmodell zur Gamification von Lernumgebungen entwickelt und angewandt. Der so entstandene Prototyp wurde anschließend um alle Game-Design-Elemente reduziert und im Rahmen einer experimentellen Studie mit zwei unabh{\"a}ngigen Versuchsgruppen mit der gamifizierten Variante verglichen. Die Untersuchung zeigte, dass die Gamification einer Lernanwendung nach dem entwickelten Vorgehensmodell grunds{\"a}tzlich das Potenzial besitzt, manche Aspekte des Nutzungserlebnisses (UX) positiv zu beeinflussen. Insbesondere hatte die Gamification positive Effekte auf die Joy of Use und die Immersivit{\"a}t. Allerdings blieb das Ausmaß der beobachteten Effekte deutlich hinter den Erwartungen zur{\"u}ck, die auf Basis verschiedener Motivationstheorien getroffen wurden. Daher erscheint Gamification besonders in außeruniversit{\"a}ren Kontexten vielversprechend, in denen der Fokus auf einer Erh{\"o}hung der Joy of Use oder einer Steigerung der Immersivit{\"a}t liegt. Allerdings lassen sich durch die Untersuchung neue Erkenntnisse zur emotionalen Wirkung von Gamification und zu einem systematischen Vorgehen bei der Gamification von Lernanwendungen herausstellen. Weiterf{\"u}hrende Forschung k{\"o}nnte an diese Erkenntnisse ankn{\"u}pfen, indem sie die emotionale Wirkung von Gamification und deren Einfluss auf die Motivation n{\"a}her untersucht. Dar{\"u}ber hinaus sollte sie Gamification auch aus einer entscheidungstheoretischen Perspektive betrachten und Analysemethoden entwickeln, mit denen entschieden werden kann, ob der Einsatz von Gamification zur Motivationssteigerung in einem spezifischen Anwendungsfall zielf{\"u}hrend ist. Unter Verwendung des entwickelten Vorgehensmodells kann es sinnvoll sein, n{\"a}her zu untersuchen, welche Faktoren insgesamt f{\"u}r das Gelingen einer Gamification-Maßnahme in Bildungskontexten entscheidend sind. Die Erkenntnisse einer solchen Untersuchung k{\"o}nnten entscheidend zur Verbesserung und Validierung des Vorgehensmodells beitragen. }, language = {de} } @phdthesis{Zoerner2021, author = {Zoerner, Dietmar}, title = {F{\"o}rderung von Aufmerksamkeit und Motivationserhalt durch digitale spielbasierte Lernsysteme mit spezifischer Eignung bei Autismus}, doi = {10.25932/publishup-52372}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-523725}, school = {Universit{\"a}t Potsdam}, pages = {xvi, 324}, year = {2021}, abstract = {Institutionelle Bildung ist f{\"u}r autistische Lernende mit vielgestaltigen und spezifischen Hindernissen verbunden. Dies gilt insbesondere im Zusammenhang mit Inklusion, deren Relevanz nicht zuletzt durch das {\"U}bereinkommen der Vereinten Nationen {\"u}ber die Rechte von Menschen mit Behinderung gegeben ist. Diese Arbeit diskutiert zahlreiche lernrelevante Besonderheiten im Kontext von Autismus und zeigt Diskrepanzen zu den nicht immer ausreichend angemessenen institutionellen Lehrkonzepten. Eine zentrale These ist hierbei, dass die ungew{\"o}hnlich intensive Aufmerksamkeit von Autist*innen f{\"u}r ihre Spezialinteressen daf{\"u}r genutzt werden kann, das Lernen mit fremdgestellten Inhalten zu erleichtern. Darauf aufbauend werden L{\"o}sungsans{\"a}tze diskutiert, welche in einem neuartigen Konzept f{\"u}r ein digitales mehrger{\"a}tebasiertes Lernspiel resultieren. Eine wesentliche Herausforderung bei der Konzeption spielbasierten Lernens besteht in der ad{\"a}quaten Einbindung von Lerninhalten in einen fesselnden narrativen Kontext. Am Beispiel von {\"U}bungen zur emotionalen Deutung von Mimik, welche f{\"u}r das Lernen von sozioemotionalen Kompetenzen besonders im Rahmen von Therapiekonzepten bei Autismus Verwendung finden, wird eine angemessene Narration vorgestellt, welche die st{\"o}rungsarme Einbindung dieser sehr speziellen Lerninhalte erm{\"o}glicht. Die Effekte der einzelnen Konzeptionselemente werden anhand eines prototypisch entwickelten Lernspiels untersucht. Darauf aufbauend zeigt eine quantitative Studie die gute Akzeptanz und Nutzerfreundlichkeit des Spiels und belegte vor allem die Verst{\"a}ndlichkeit der Narration und der Spielelemente. Ein weiterer Schwerpunkt liegt in der minimalinvasiven Untersuchung m{\"o}glicher St{\"o}rungen des Spielerlebnisses durch den Wechsel zwischen verschiedenen Endger{\"a}ten, f{\"u}r die ein innovatives Messverfahren entwickelt wurde. Im Ergebnis beleuchtet diese Arbeit die Bedeutung und die Grenzen von spielbasierten Ans{\"a}tzen f{\"u}r autistische Lernende. Ein großer Teil der vorgestellten Konzepte l{\"a}sst sich auf andersartige Lernszenarien {\"u}bertragen. Das daf{\"u}r entwickelte technische Framework zur Realisierung narrativer Lernpfade ist ebenfalls darauf vorbereitet, f{\"u}r weitere Lernszenarien, gerade auch im institutionellen Kontext, Verwendung zu finden.}, language = {de} } @phdthesis{Weise2021, author = {Weise, Matthias}, title = {Auswahl von Selektions- und Manipulationstechniken f{\"u}r Virtual Reality-Anwendungen}, doi = {10.25932/publishup-53458}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-534586}, school = {Universit{\"a}t Potsdam}, pages = {iii, 218}, year = {2021}, abstract = {Die stetige Weiterentwicklung von VR-Systemen bietet neue M{\"o}glichkeiten der Interaktion mit virtuellen Objekten im dreidimensionalen Raum, stellt Entwickelnde von VRAnwendungen aber auch vor neue Herausforderungen. Selektions- und Manipulationstechniken m{\"u}ssen unter Ber{\"u}cksichtigung des Anwendungsszenarios, der Zielgruppe und der zur Verf{\"u}gung stehenden Ein- und Ausgabeger{\"a}te ausgew{\"a}hlt werden. Diese Arbeit leistet einen Beitrag dazu, die Auswahl von passenden Interaktionstechniken zu unterst{\"u}tzen. Hierf{\"u}r wurde eine repr{\"a}sentative Menge von Selektions- und Manipulationstechniken untersucht und, unter Ber{\"u}cksichtigung existierender Klassifikationssysteme, eine Taxonomie entwickelt, die die Analyse der Techniken hinsichtlich interaktionsrelevanter Eigenschaften erm{\"o}glicht. Auf Basis dieser Taxonomie wurden Techniken ausgew{\"a}hlt, die in einer explorativen Studie verglichen wurden, um R{\"u}ckschl{\"u}sse auf die Dimensionen der Taxonomie zu ziehen und neue Indizien f{\"u}r Vor- und Nachteile der Techniken in spezifischen Anwendungsszenarien zu generieren. Die Ergebnisse der Arbeit m{\"u}nden in eine Webanwendung, die Entwickelnde von VR-Anwendungen gezielt dabei unterst{\"u}tzt, passende Selektions- und Manipulationstechniken f{\"u}r ein Anwendungsszenario auszuw{\"a}hlen, indem Techniken auf Basis der Taxonomie gefiltert und unter Verwendung der Resultate aus der Studie sortiert werden k{\"o}nnen.}, language = {de} } @article{KreowskyStabernack2021, author = {Kreowsky, Philipp and Stabernack, Christian Benno}, title = {A full-featured FPGA-based pipelined architecture for SIFT extraction}, series = {IEEE access : practical research, open solutions / Institute of Electrical and Electronics Engineers}, volume = {9}, journal = {IEEE access : practical research, open solutions / Institute of Electrical and Electronics Engineers}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {New York, NY}, issn = {2169-3536}, doi = {10.1109/ACCESS.2021.3104387}, pages = {128564 -- 128573}, year = {2021}, abstract = {Image feature detection is a key task in computer vision. Scale Invariant Feature Transform (SIFT) is a prevalent and well known algorithm for robust feature detection. However, it is computationally demanding and software implementations are not applicable for real-time performance. In this paper, a versatile and pipelined hardware implementation is proposed, that is capable of computing keypoints and rotation invariant descriptors on-chip. All computations are performed in single precision floating-point format which makes it possible to implement the original algorithm with little alteration. Various rotation resolutions and filter kernel sizes are supported for images of any resolution up to ultra-high definition. For full high definition images, 84 fps can be processed. Ultra high definition images can be processed at 21 fps.}, language = {en} } @phdthesis{Sahlmann2021, author = {Sahlmann, Kristina}, title = {Network management with semantic descriptions for interoperability on the Internet of Things}, doi = {10.25932/publishup-52984}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-529846}, school = {Universit{\"a}t Potsdam}, pages = {x, 272}, year = {2021}, abstract = {The Internet of Things (IoT) is a system of physical objects that can be discovered, monitored, controlled, or interacted with by electronic devices that communicate over various networking interfaces and eventually can be connected to the wider Internet. [Guinard and Trifa, 2016]. IoT devices are equipped with sensors and/or actuators and may be constrained in terms of memory, computational power, network bandwidth, and energy. Interoperability can help to manage such heterogeneous devices. Interoperability is the ability of different types of systems to work together smoothly. There are four levels of interoperability: physical, network and transport, integration, and data. The data interoperability is subdivided into syntactic and semantic data. Semantic data describes the meaning of data and the common understanding of vocabulary e.g. with the help of dictionaries, taxonomies, ontologies. To achieve interoperability, semantic interoperability is necessary. Many organizations and companies are working on standards and solutions for interoperability in the IoT. However, the commercial solutions produce a vendor lock-in. They focus on centralized approaches such as cloud-based solutions. This thesis proposes a decentralized approach namely Edge Computing. Edge Computing is based on the concepts of mesh networking and distributed processing. This approach has an advantage that information collection and processing are placed closer to the sources of this information. The goals are to reduce traffic, latency, and to be robust against a lossy or failed Internet connection. We see management of IoT devices from the network configuration management perspective. This thesis proposes a framework for network configuration management of heterogeneous, constrained IoT devices by using semantic descriptions for interoperability. The MYNO framework is an acronym for MQTT, YANG, NETCONF and Ontology. The NETCONF protocol is the IETF standard for network configuration management. The MQTT protocol is the de-facto standard in the IoT. We picked up the idea of the NETCONF-MQTT bridge, originally proposed by Scheffler and Bonneß[2017], and extended it with semantic device descriptions. These device descriptions provide a description of the device capabilities. They are based on the oneM2M Base ontology and formalized by the Semantic Web Standards. The novel approach is using a ontology-based device description directly on a constrained device in combination with the MQTT protocol. The bridge was extended in order to query such descriptions. Using a semantic annotation, we achieved that the device capabilities are self-descriptive, machine readable and re-usable. The concept of a Virtual Device was introduced and implemented, based on semantic device descriptions. A Virtual Device aggregates the capabilities of all devices at the edge network and contributes therefore to the scalability. Thus, it is possible to control all devices via a single RPC call. The model-driven NETCONF Web-Client is generated automatically from this YANG model which is generated by the bridge based on the semantic device description. The Web-Client provides a user-friendly interface, offers RPC calls and displays sensor values. We demonstrate the feasibility of this approach in different use cases: sensor and actuator scenarios, as well as event configuration and triggering. The semantic approach results in increased memory overhead. Therefore, we evaluated CBOR and RDF HDT for optimization of ontology-based device descriptions for use on constrained devices. The evaluation shows that CBOR is not suitable for long strings and RDF HDT is a promising candidate but is still a W3C Member Submission. Finally, we used an optimized JSON-LD format for the syntax of the device descriptions. One of the security tasks of network management is the distribution of firmware updates. The MYNO Update Protocol (MUP) was developed and evaluated on constrained devices CC2538dk and 6LoWPAN. The MYNO update process is focused on freshness and authenticity of the firmware. The evaluation shows that it is challenging but feasible to bring the firmware updates to constrained devices using MQTT. As a new requirement for the next MQTT version, we propose to add a slicing feature for the better support of constrained devices. The MQTT broker should slice data to the maximum packet size specified by the device and transfer it slice-by-slice. For the performance and scalability evaluation of MYNO framework, we setup the High Precision Agriculture demonstrator with 10 ESP-32 NodeMCU boards at the edge of the network. The ESP-32 NodeMCU boards, connected by WLAN, were equipped with six sensors and two actuators. The performance evaluation shows that the processing of ontology-based descriptions on a Raspberry Pi 3B with the RDFLib is a challenging task regarding computational power. Nevertheless, it is feasible because it must be done only once per device during the discovery process. The MYNO framework was tested with heterogeneous devices such as CC2538dk from Texas Instruments, Arduino Y{\´u}n Rev 3, and ESP-32 NodeMCU, and IP-based networks such as 6LoWPAN and WLAN. Summarizing, with the MYNO framework we could show that the semantic approach on constrained devices is feasible in the IoT.}, language = {en} } @phdthesis{Grum2021, author = {Grum, Marcus}, title = {Construction of a concept of neuronal modeling}, year = {2021}, abstract = {The business problem of having inefficient processes, imprecise process analyses, and simulations as well as non-transparent artificial neuronal network models can be overcome by an easy-to-use modeling concept. With the aim of developing a flexible and efficient approach to modeling, simulating, and optimizing processes, this paper proposes a flexible Concept of Neuronal Modeling (CoNM). The modeling concept, which is described by the modeling language designed and its mathematical formulation and is connected to a technical substantiation, is based on a collection of novel sub-artifacts. As these have been implemented as a computational model, the set of CoNM tools carries out novel kinds of Neuronal Process Modeling (NPM), Neuronal Process Simulations (NPS), and Neuronal Process Optimizations (NPO). The efficacy of the designed artifacts was demonstrated rigorously by means of six experiments and a simulator of real industrial production processes.}, language = {en} } @article{BauerHerwigLienhardetal.2021, author = {Bauer, Chris and Herwig, Ralf and Lienhard, Matthias and Prasse, Paul and Scheffer, Tobias and Schuchhardt, Johannes}, title = {Large-scale literature mining to assess the relation between anti-cancer drugs and cancer types}, series = {Journal of translational medicine}, volume = {19}, journal = {Journal of translational medicine}, number = {1}, publisher = {BioMed Central}, address = {London}, issn = {1479-5876}, doi = {10.1186/s12967-021-02941-z}, pages = {13}, year = {2021}, abstract = {Background: There is a huge body of scientific literature describing the relation between tumor types and anti-cancer drugs. The vast amount of scientific literature makes it impossible for researchers and physicians to extract all relevant information manually. Methods: In order to cope with the large amount of literature we applied an automated text mining approach to assess the relations between 30 most frequent cancer types and 270 anti-cancer drugs. We applied two different approaches, a classical text mining based on named entity recognition and an AI-based approach employing word embeddings. The consistency of literature mining results was validated with 3 independent methods: first, using data from FDA approvals, second, using experimentally measured IC-50 cell line data and third, using clinical patient survival data. Results: We demonstrated that the automated text mining was able to successfully assess the relation between cancer types and anti-cancer drugs. All validation methods showed a good correspondence between the results from literature mining and independent confirmatory approaches. The relation between most frequent cancer types and drugs employed for their treatment were visualized in a large heatmap. All results are accessible in an interactive web-based knowledge base using the following link: . Conclusions: Our approach is able to assess the relations between compounds and cancer types in an automated manner. Both, cancer types and compounds could be grouped into different clusters. Researchers can use the interactive knowledge base to inspect the presented results and follow their own research questions, for example the identification of novel indication areas for known drugs.}, language = {en} } @article{HuangRichterKleickmannetal.2021, author = {Huang, Yizhen and Richter, Eric and Kleickmann, Thilo and Wiepke, Axel and Richter, Dirk}, title = {Classroom complexity affects student teachers' behavior in a VR classroom}, series = {Computers \& education : an international journal}, volume = {163}, journal = {Computers \& education : an international journal}, publisher = {Elsevier}, address = {Oxford}, issn = {0360-1315}, doi = {10.1016/j.compedu.2020.104100}, pages = {15}, year = {2021}, abstract = {Student teachers often struggle to keep track of everything that is happening in the classroom, and particularly to notice and respond when students cause disruptions. The complexity of the classroom environment is a potential contributing factor that has not been empirically tested. In this experimental study, we utilized a virtual reality (VR) classroom to examine whether classroom complexity affects the likelihood of student teachers noticing disruptions and how they react after noticing. Classroom complexity was operationalized as the number of disruptions and the existence of overlapping disruptions (multidimensionality) as well as the existence of parallel teaching tasks (simultaneity). Results showed that student teachers (n = 50) were less likely to notice the scripted disruptions, and also less likely to respond to the disruptions in a comprehensive and effortful manner when facing greater complexity. These results may have implications for both teacher training and the design of VR for training or research purpose. This study contributes to the field from two aspects: 1) it revealed how features of the classroom environment can affect student teachers' noticing of and reaction to disruptions; and 2) it extends the functionality of the VR environment-from a teacher training tool to a testbed of fundamental classroom processes that are difficult to manipulate in real-life.}, language = {en} }