TY  - CHAP
A1  - Grum, Marcus
ED  - Shishkov, Boris
T1  - Managing multi-site artificial neural networks’ activation rates and activation cycles
T2  - Business modeling and software design : 14th International Symposium, BMSD 2024, Luxembourg City, Luxembourg, July 1–3, 2024, proceedings
N2  - Traditionally, business models and software designs used to model the usage of artificial intelligence (AI) at a very specific point in the process or rather fix implemented application. Since applications can be based on AI, such as networked artificial neural networks (ANN) on top of which applications are installed, these on-top applications can be instructed directly from their underlying ANN compartments [1]. However, with the integration of several AI-based systems, their coordination is a highly relevant target factor for the operation and improvement of networked processes, such as they can be found in cross-organizational production contexts spanning multiple distributed locations. This work aims to extend prior research on managing artificial knowledge transfers among interlinked AIs as coordination instrument by examining effects of different activation types (respective activation rates and cycles) on by ANN-instructed production machines. In a design-science-oriented way, this paper conceptualizes rhythmic state descriptions for dynamic systems and associated 14 experiment designs. Two experiments have been realized, analyzed and evaluated thereafter in regard with their activities and processes induced. Findings show that the simulator [2] used and experiments designed and realized, here, (I) enable research on ANN activation types, (II) illustrate ANN-based production networks disrupted by activation types and clarify the need for harmonizing them. Further, (III) management interventions are derived for harmonizing interlinked ANNs. This study establishes the importance of site-specific coordination mechanisms and novel forms of management interventions as drivers of efficient artificial knowledge transfer.
Y1  - 2024
SN  - 978-3-031-64072-8
SN  - 978-3-031-64073-5
U6  - https://doi.org/10.1007/978-3-031-64073-5_17
SP  - 258
EP  - 269
PB  - Springer
CY  - Cham
ER  - 
TY  - GEN
A1  - Kurpiers, Jona
A1  - Neher, Dieter
T1  - Dispersive Non-Geminate Recombination in an Amorphous Polymer:Fullerene Blend
N2  - Recombination of free charge is a key process limiting the performance of solar cells. For low mobility materials, such as organic semiconductors, the kinetics of non-geminate recombination (NGR) is strongly linked to the motion of charges. As these materials possess significant disorder, thermalization of photogenerated carriers in the inhomogeneously broadened density of state distribution is an unavoidable process. Despite its general importance, knowledge about the kinetics of NGR in complete organic solar cells is rather limited. We employ time delayed collection field (TDCF) experiments to study the recombination of photogenerated charge in the high-performance polymer:fullerene blend PCDTBT:PCBM. NGR in the bulk of this amorphous blend is shown to be highly dispersive, with a continuous reduction of the recombination coefficient throughout the entire time scale, until all charge carriers have either been extracted or recombined. Rapid, contact-mediated recombination is identified as an additional loss channel, which, if not properly taken into account, would erroneously suggest a pronounced field dependence of charge generation. These findings are in stark contrast to the results of TDCF experiments on photovoltaic devices made from ordered blends, such as P3HT:PCBM, where non-dispersive recombination was proven to dominate the charge carrier dynamics under application relevant conditions.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 228 
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-91541
ER  - 
TY  - GEN
A1  - Neher, Dieter
A1  - Kniepert, Juliane
A1  - Elimelech, Arik
A1  - Koster, L. Jan Anton
T1  - A New Figure of Merit for Organic Solar Cells with Transport-limited Photocurrents
N2  - Compared to their inorganic counterparts, organic semiconductors suffer from relatively low charge carrier mobilities. Therefore, expressions derived for inorganic solar cells to correlate characteristic performance parameters to material properties are prone to fail when applied to organic devices. This is especially true for the classical Shockley-equation commonly used to describe current-voltage (JV)-curves, as it assumes a high electrical conductivity of the charge transporting material. Here, an analytical expression for the JV-curves of organic solar cells is derived based on a previously published analytical model. This expression, bearing a similar functional dependence as the Shockley-equation, delivers a new figure of merit α to express the balance between free charge recombination and extraction in low mobility photoactive materials. This figure of merit is shown to determine critical device parameters such as the apparent series resistance and the fill factor.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 225 
KW  - Electronic and spintronic devices
KW  - Semiconductors
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-91414
ER  - 
TY  - JOUR
A1  - Kurpiers, Jona
A1  - Neher, Dieter
T1  - Dispersive Non-Geminate Recombination in an Amorphous Polymer:Fullerene Blend
JF  - Scientific reports
N2  - Recombination of free charge is a key process limiting the performance of solar cells. For low mobility materials, such as organic semiconductors, the kinetics of non-geminate recombination (NGR) is strongly linked to the motion of charges. As these materials possess significant disorder, thermalization of photogenerated carriers in the inhomogeneously broadened density of state distribution is an unavoidable process. Despite its general importance, knowledge about the kinetics of NGR in complete organic solar cells is rather limited. We employ time delayed collection field (TDCF) experiments to study the recombination of photogenerated charge in the high-performance polymer:fullerene blend PCDTBT:PCBM. NGR in the bulk of this amorphous blend is shown to be highly dispersive, with a continuous reduction of the recombination coefficient throughout the entire time scale, until all charge carriers have either been extracted or recombined. Rapid, contact-mediated recombination is identified as an additional loss channel, which, if not properly taken into account, would erroneously suggest a pronounced field dependence of charge generation. These findings are in stark contrast to the results of TDCF experiments on photovoltaic devices made from ordered blends, such as P3HT:PCBM, where non-dispersive recombination was proven to dominate the charge carrier dynamics under application relevant conditions.
Y1  - 2016
U6  - https://doi.org/10.1038/srep26832
SN  - 2045-2322
VL  - 6
PB  - Nature Publishing Group
CY  - London
ER  - 
TY  - JOUR
A1  - Neher, Dieter
A1  - Kniepert, Juliane
A1  - Elimelech, Arik
A1  - Koster, L. Jan Anton
T1  - A New Figure of Merit for Organic Solar Cells with Transport-limited Photocurrents
JF  - Scientific reports
N2  - Compared to their inorganic counterparts, organic semiconductors suffer from relatively low charge carrier mobilities. Therefore, expressions derived for inorganic solar cells to correlate characteristic performance parameters to material properties are prone to fail when applied to organic devices. This is especially true for the classical Shockley-equation commonly used to describe current-voltage (JV)-curves, as it assumes a high electrical conductivity of the charge transporting material. Here, an analytical expression for the JV-curves of organic solar cells is derived based on a previously published analytical model. This expression, bearing a similar functional dependence as the Shockley-equation, delivers a new figure of merit α to express the balance between free charge recombination and extraction in low mobility photoactive materials. This figure of merit is shown to determine critical device parameters such as the apparent series resistance and the fill factor.
KW  - Electronic and spintronic devices
KW  - Semiconductors
Y1  - 2016
U6  - https://doi.org/10.1038/srep24861
SN  - 2045-2322
VL  - 6
PB  - Nature Publishing Group
CY  - London
ER  - 
TY  - JOUR
A1  - Schindler, Daniel
A1  - Moldenhawer, Ted
A1  - Stange, Maike
A1  - Lepro, Valentino
A1  - Beta, Carsten
A1  - Holschneider, Matthias
A1  - Huisinga, Wilhelm
T1  - Analysis of protrusion dynamics in amoeboid cell motility by means of regularized contour flows
JF  - PLoS Computational Biology : a new community journal
N2  - Amoeboid cell motility is essential for a wide range of biological processes including wound healing, embryonic morphogenesis, and cancer metastasis. It relies on complex dynamical patterns of cell shape changes that pose long-standing challenges to mathematical modeling and raise a need for automated and reproducible approaches to extract quantitative morphological features from image sequences. Here, we introduce a theoretical framework and a computational method for obtaining smooth representations of the spatiotemporal contour dynamics from stacks of segmented microscopy images. Based on a Gaussian process regression we propose a one-parameter family of regularized contour flows that allows us to continuously track reference points (virtual markers) between successive cell contours. We use this approach to define a coordinate system on the moving cell boundary and to represent different local geometric quantities in this frame of reference. In particular, we introduce the local marker dispersion as a measure to identify localized membrane expansions and provide a fully automated way to extract the properties of such expansions, including their area and growth time. The methods are available as an open-source software package called AmoePy, a Python-based toolbox for analyzing amoeboid cell motility (based on time-lapse microscopy data), including a graphical user interface and detailed documentation. Due to the mathematical rigor of our framework, we envision it to be of use for the development of novel cell motility models. We mainly use experimental data of the social amoeba Dictyostelium discoideum to illustrate and validate our approach. <br /> Author summary Amoeboid motion is a crawling-like cell migration that plays an important key role in multiple biological processes such as wound healing and cancer metastasis. This type of cell motility results from expanding and simultaneously contracting parts of the cell membrane. From fluorescence images, we obtain a sequence of points, representing the cell membrane, for each time step. By using regression analysis on these sequences, we derive smooth representations, so-called contours, of the membrane. Since the number of measurements is discrete and often limited, the question is raised of how to link consecutive contours with each other. In this work, we present a novel mathematical framework in which these links are described by regularized flows allowing a certain degree of concentration or stretching of neighboring reference points on the same contour. This stretching rate, the so-called local dispersion, is used to identify expansions and contractions of the cell membrane providing a fully automated way of extracting properties of these cell shape changes. We applied our methods to time-lapse microscopy data of the social amoeba Dictyostelium discoideum.
Y1  - 2021
U6  - https://doi.org/10.1371/journal.pcbi.1009268
SN  - 1553-734X
SN  - 1553-7358
VL  - 17
IS  - 8
PB  - PLoS
CY  - San Fransisco
ER  - 
TY  - GEN
A1  - Panzer, Marcel
A1  - Bender, Benedict
A1  - Gronau, Norbert
T1  - Neural agent-based production planning and control
BT  - an architectural review
T2  - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe
N2  - Nowadays, production planning and control must cope with mass customization, increased fluctuations in demand, and high competition pressures. Despite prevailing market risks, planning accuracy and increased adaptability in the event of disruptions or failures must be ensured, while simultaneously optimizing key process indicators. To manage that complex task, neural networks that can process large quantities of high-dimensional data in real time have been widely adopted in recent years. Although these are already extensively deployed in production systems, a systematic review of applications and implemented agent embeddings and architectures has not yet been conducted. The main contribution of this paper is to provide researchers and practitioners with an overview of applications and applied embeddings and to motivate further research in neural agent-based production. Findings indicate that neural agents are not only deployed in diverse applications, but are also increasingly implemented in multi-agent environments or in combination with conventional methods — leveraging performances compared to benchmarks and reducing dependence on human experience. This not only implies a more sophisticated focus on distributed production resources, but also broadening the perspective from a local to a global scale. Nevertheless, future research must further increase scalability and reproducibility to guarantee a simplified transfer of results to reality.
T3  - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe - 172 
KW  - production planning and control
KW  - machine learning
KW  - neural networks
KW  - systematic literature review
KW  - taxonomy
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-604777
SN  - 1867-5808
ER  - 
TY  - JOUR
A1  - Panzer, Marcel
A1  - Bender, Benedict
A1  - Gronau, Norbert
T1  - Neural agent-based production planning and control
BT  - an architectural review
JF  - Journal of Manufacturing Systems
N2  - Nowadays, production planning and control must cope with mass customization, increased fluctuations in demand, and high competition pressures. Despite prevailing market risks, planning accuracy and increased adaptability in the event of disruptions or failures must be ensured, while simultaneously optimizing key process indicators. To manage that complex task, neural networks that can process large quantities of high-dimensional data in real time have been widely adopted in recent years. Although these are already extensively deployed in production systems, a systematic review of applications and implemented agent embeddings and architectures has not yet been conducted. The main contribution of this paper is to provide researchers and practitioners with an overview of applications and applied embeddings and to motivate further research in neural agent-based production. Findings indicate that neural agents are not only deployed in diverse applications, but are also increasingly implemented in multi-agent environments or in combination with conventional methods — leveraging performances compared to benchmarks and reducing dependence on human experience. This not only implies a more sophisticated focus on distributed production resources, but also broadening the perspective from a local to a global scale. Nevertheless, future research must further increase scalability and reproducibility to guarantee a simplified transfer of results to reality.
KW  - production planning and control
KW  - machine learning
KW  - neural networks
KW  - systematic literature review
KW  - taxonomy
Y1  - 2022
U6  - https://doi.org/10.1016/j.jmsy.2022.10.019
SN  - 0278-6125
SN  - 1878-6642
VL  - 65
SP  - 743
EP  - 766
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Tavakoli, Hamad
A1  - Alirezazadeh, Pendar
A1  - Hedayatipour, Ava
A1  - Nasib, A. H. Banijamali
A1  - Landwehr, Niels
T1  - Leaf image-based classification of some common bean cultivars using discriminative convolutional neural networks
JF  - Computers and electronics in agriculture : COMPAG online ; an international journal
N2  - In recent years, many efforts have been made to apply image processing techniques for plant leaf identification. However, categorizing leaf images at the cultivar/variety level, because of the very low inter-class variability, is still a challenging task. In this research, we propose an automatic discriminative method based on convolutional neural networks (CNNs) for classifying 12 different cultivars of common beans that belong to three various species. We show that employing advanced loss functions, such as Additive Angular Margin Loss and Large Margin Cosine Loss, instead of the standard softmax loss function for the classification can yield better discrimination between classes and thereby mitigate the problem of low inter-class variability. The method was evaluated by classifying species (level I), cultivars from the same species (level II), and cultivars from different species (level III), based on images from the leaf foreside and backside. The results indicate that the performance of the classification algorithm on the leaf backside image dataset is superior. The maximum mean classification accuracies of 95.86, 91.37 and 86.87% were obtained at the levels I, II and III, respectively. The proposed method outperforms the previous relevant works and provides a reliable approach for plant cultivars identification.
KW  - Bean
KW  - Plant identification
KW  - Digital image analysis
KW  - VGG16
KW  - Loss
KW  - functions
Y1  - 2021
U6  - https://doi.org/10.1016/j.compag.2020.105935
SN  - 0168-1699
SN  - 1872-7107
VL  - 181
PB  - Elsevier
CY  - Amsterdam [u.a.]
ER  - 
TY  - GEN
A1  - Hägele, Claudia
A1  - Schlagenhauf, Florian
A1  - Rapp, Michael A.
A1  - Sterzer, Philipp
A1  - Beck, Anne
A1  - Bermpohl, Felix
A1  - Stoy, Meline
A1  - Ströhle, Andreas
A1  - Wittchen, Hans-Ulrich
A1  - Dolan, Raymond J.
A1  - Heinz, Andreas
T1  - Dimensional psychiatry
BT  - reward dysfunction and depressive mood across psychiatric disorders
T2  - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe
N2  - A dimensional approach in psychiatry aims to identify core mechanisms of mental disorders across nosological boundaries.

We compared anticipation of reward between major psychiatric disorders, and investigated whether reward anticipation is impaired in several mental disorders and whether there is a common psychopathological correlate (negative mood) of such an impairment.

We used functional magnetic resonance imaging (fMRI) and a monetary incentive delay (MID) task to study the functional correlates of reward anticipation across major psychiatric disorders in 184 subjects, with the diagnoses of alcohol dependence (n = 26), schizophrenia (n = 44), major depressive disorder (MDD, n = 24), bipolar disorder (acute manic episode, n = 13), attention deficit/hyperactivity disorder (ADHD, n = 23), and healthy controls (n = 54). Subjects' individual Beck Depression Inventory-and State-Trait Anxiety Inventory-scores were correlated with clusters showing significant activation during reward anticipation.

During reward anticipation, we observed significant group differences in ventral striatal (VS) activation: patients with schizophrenia, alcohol dependence, and major depression showed significantly less ventral striatal activation compared to healthy controls. Depressive symptoms correlated with dysfunction in reward anticipation regardless of diagnostic entity. There was no significant correlation between anxiety symptoms and VS functional activation.

Our findings demonstrate a neurobiological dysfunction related to reward prediction that transcended disorder categories and was related to measures of depressed mood. The findings underline the potential of a dimensional approach in psychiatry and strengthen the hypothesis that neurobiological research in psychiatric disorders can be targeted at core mechanisms that are likely to be implicated in a range of clinical entities.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 653 
KW  - dimensional
KW  - fMRI
KW  - reward system
KW  - ventral striatum
KW  - monetary incentive delay task
KW  - depressive symptoms
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431064
SN  - 1866-8364
IS  - 653
SP  - 331
EP  - 341
ER  - 
TY  - THES
A1  - Jiang, Lan
T1  - Discovering metadata in data files
N2  - It is estimated that data scientists spend up to 80% of the time exploring, cleaning, and transforming their data. A major reason for that expenditure is the lack of knowledge about the used data, which are often from different sources and have heterogeneous structures. As a means to describe various properties of data, metadata can help data scientists understand and prepare their data, saving time for innovative and valuable data analytics. However, metadata do not always exist: some data file formats are not capable of storing them; metadata were deleted for privacy concerns; legacy data may have been produced by systems that were not designed to store and handle meta- data. As data are being produced at an unprecedentedly fast pace and stored in diverse formats, manually creating metadata is not only impractical but also error-prone, demanding automatic approaches for metadata detection.

In this thesis, we are focused on detecting metadata in CSV files – a type of plain-text file that, similar to spreadsheets, may contain different types of content at arbitrary positions. We propose a taxonomy of metadata in CSV files and specifically address the discovery of three different metadata: line and cell type, aggregations, and primary keys and foreign keys.

Data are organized in an ad-hoc manner in CSV files, and do not follow a fixed structure, which is assumed by common data processing tools. Detecting the structure of such files is a prerequisite of extracting information from them, which can be addressed by detecting the semantic type, such as header, data, derived, or footnote, of each line or each cell. We propose the supervised- learning approach Strudel to detect the type of lines and cells. CSV files may also include aggregations. An aggregation represents the arithmetic relationship between a numeric cell and a set of other numeric cells. Our proposed AggreCol algorithm is capable of detecting aggregations of five arithmetic functions in CSV files. Note that stylistic features, such as font style and cell background color, do not exist in CSV files. Our proposed algorithms address the respective problems by using only content, contextual, and computational features.

Storing a relational table is also a common usage of CSV files. Primary keys and foreign keys are important metadata for relational databases, which are usually not present for database instances dumped as plain-text files. We propose the HoPF algorithm to holistically detect both constraints in relational databases. Our approach is capable of distinguishing true primary and foreign keys from a great amount of spurious unique column combinations and inclusion dependencies, which can be detected by state-of-the-art data profiling algorithms.
N2  - Schätzungen zufolge verbringen Datenwissenschaftler bis zu 80% ihrer Zeit mit der Erkundung, Bereinigung und Umwandlung ihrer Daten. Ein Hauptgrund für diesen Aufwand ist das fehlende Wissen über die verwendeten Daten, die oft aus unterschiedlichen Quellen stammen und heterogene Strukturen aufweisen.
Als Mittel zur Beschreibung verschiedener Dateneigenschaften können Metadaten Datenwissenschaftlern dabei helfen, ihre Daten zu verstehen und aufzubereiten, und so wertvolle Zeit die Datenanalysen selbst sparen.
Metadaten sind jedoch nicht immer vorhanden: Zum Beispiel sind einige Dateiformate nicht in der Lage, sie zu speichern; Metadaten können aus Datenschutzgründen gelöscht worden sein; oder ältere Daten wurden möglicherweise von Systemen erzeugt, die nicht für die Speicherung und Verarbeitung von Metadaten konzipiert waren. Da Daten in einem noch nie dagewesenen Tempo produziert und in verschiedenen Formaten gespeichert werden, ist die manuelle Erstellung von Metadaten nicht nur unpraktisch, sondern auch fehleranfällig, so dass automatische Ansätze zur Metadatenerkennung erforderlich sind.

In dieser Arbeit konzentrieren wir uns auf die Erkennung von Metadaten in CSV-Dateien - einer Art von Klartextdateien, die, ähnlich wie Tabellenkalkulationen, verschiedene Arten von Inhalten an beliebigen Positionen enthalten können. Wir schlagen eine Taxonomie der Metadaten in CSV-Dateien vor und befassen uns speziell mit der Erkennung von drei verschiedenen Metadaten: Zeile und Zellensemantischer Typ, Aggregationen sowie Primärschlüssel und Fremdschlüssel.

Die Daten sind in CSV-Dateien ad-hoc organisiert und folgen keiner festen Struktur, wie sie von gängigen Datenverarbeitungsprogrammen angenommen wird. Die Erkennung der Struktur solcher Dateien ist eine Voraussetzung für die Extraktion von Informationen aus ihnen, die durch die Erkennung des semantischen Typs jeder Zeile oder jeder Zelle, wie z. B. Kopfzeile, Daten, abgeleitete Daten oder Fußnote, angegangen werden kann. Wir schlagen den Ansatz des überwachten Lernens, genannt „Strudel“ vor, um den strukturellen Typ von Zeilen und Zellen zu klassifizieren. CSV-Dateien können auch Aggregationen enthalten. Eine Aggregation stellt die arithmetische Beziehung zwischen einer numerischen Zelle und einer Reihe anderer numerischer Zellen dar. Der von uns vorgeschlagene „Aggrecol“-Algorithmus ist in der Lage, Aggregationen von fünf arithmetischen Funktionen in CSV-Dateien zu erkennen. Da stilistische Merkmale wie Schriftart und Zellhintergrundfarbe in CSV-Dateien nicht vorhanden sind, die von uns vorgeschlagenen Algorithmen die entsprechenden Probleme, indem sie nur die Merkmale Inhalt, Kontext und Berechnungen verwenden.

Die Speicherung einer relationalen Tabelle ist ebenfalls eine häufige Verwendung von CSV-Dateien. Primär- und Fremdschlüssel sind wichtige Metadaten für relationale Datenbanken, die bei Datenbankinstanzen, die als reine Textdateien gespeichert werden, normalerweise nicht vorhanden sind. Wir schlagen den „HoPF“-Algorithmus vor, um beide Constraints in relationalen Datenbanken ganzheitlich zu erkennen. Unser Ansatz ist in der Lage, echte Primär- und Fremdschlüssel von einer großen Menge an falschen eindeutigen Spaltenkombinationen und Einschlussabhängigkeiten zu unterscheiden, die von modernen Data-Profiling-Algorithmen erkannt werden können.
KW  - data preparation
KW  - metadata detection
KW  - data wrangling
KW  - Datenaufbereitung
KW  - Datentransformation
KW  - Erkennung von Metadaten
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-566204
ER  - 
TY  - JOUR
A1  - Rosin, Paul L.
A1  - Lai, Yu-Kun
A1  - Mould, David
A1  - Yi, Ran
A1  - Berger, Itamar
A1  - Doyle, Lars
A1  - Lee, Seungyong
A1  - Li, Chuan
A1  - Liu, Yong-Jin
A1  - Semmo, Amir
A1  - Shamir, Ariel
A1  - Son, Minjung
A1  - Winnemöller, Holger
T1  - NPRportrait 1.0: A three-level benchmark for non-photorealistic rendering of portraits
JF  - Computational visual media
N2  - Recently, there has been an upsurge of activity in image-based non-photorealistic rendering (NPR), and in particular portrait image stylisation, due to the advent of neural style transfer (NST). However, the state of performance evaluation in this field is poor, especially compared to the norms in the computer vision and machine learning communities. Unfortunately, the task of evaluating image stylisation is thus far not well defined, since it involves subjective, perceptual, and aesthetic aspects. To make progress towards a solution, this paper proposes a new structured, three-level, benchmark dataset for the evaluation of stylised portrait images. Rigorous criteria were used for its construction, and its consistency was validated by user studies. Moreover, a new methodology has been developed for evaluating portrait stylisation algorithms, which makes use of the different benchmark levels as well as annotations provided by user studies regarding the characteristics of the faces. We perform evaluation for a wide variety of image stylisation methods (both portrait-specific and general purpose, and also both traditional NPR approaches and NST) using the new benchmark dataset.
KW  - non-photorealistic rendering (NPR)
KW  - image stylization
KW  - style transfer
KW  - portrait
KW  - evaluation
KW  - benchmark
Y1  - 2022
U6  - https://doi.org/10.1007/s41095-021-0255-3
SN  - 2096-0433
SN  - 2096-0662
VL  - 8
IS  - 3
SP  - 445
EP  - 465
PB  - Springer Nature
CY  - London
ER  - 
TY  - CHAP
A1  - Rojahn, Marcel
A1  - Gronau, Norbert
ED  - Bui, Tung X.
T1  - Openness indicators for the evaluation of digital platforms between the launch and maturity phase
T2  - Proceedings of the 57th Annual Hawaii International Conference on System Sciences
N2  - In recent years, the evaluation of digital platforms has become an important focus in the field of information systems science. The identification of influential indicators that drive changes in digital platforms, specifically those related to openness, is still an unresolved issue. This paper addresses the challenge of identifying measurable indicators and characterizing the transition from launch to maturity in digital platforms. It proposes a systematic analytical approach to identify relevant openness indicators for evaluation purposes. The main contributions of this study are the following (1) the development of a comprehensive procedure for analyzing indicators, (2) the categorization of indicators as evaluation metrics within a multidimensional grid-box model, (3) the selection and evaluation of relevant indicators, (4) the identification and assessment of digital platform architectures during the launch-to-maturity transition, and (5) the evaluation of the applicability of the conceptualization and design process for digital platform evaluation.
KW  - federated industrial platform ecosystems
KW  - technologies
KW  - business models
KW  - data-driven artifacts
KW  - design-science research
KW  - digital platform openness
KW  - evaluation
KW  - morphological analysis
Y1  - 2024
SN  - 978-0-99813-317-1
SP  - 4516
EP  - 4525
PB  - Department of IT Management Shidler College of Business University of Hawaii
CY  - Honolulu, HI
ER  - 
TY  - GEN
A1  - Fandiño, Jorge
T1  - Founded (auto)epistemic equilibrium logic satisfies epistemic splitting
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1060 
KW  - answer set programming
KW  - epistemic specifications
KW  - epistemic logic programs
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469685
SN  - 1866-8372
IS  - 1060
SP  - 671
EP  - 687
ER  - 
TY  - JOUR
A1  - Cabalar, Pedro
A1  - Fandiño, Jorge
A1  - Fariñas del Cerro, Luis
T1  - Splitting epistemic logic programs
JF  - Theory and practice of logic programming / publ. for the Association for Logic Programming
N2  - Epistemic logic programs constitute an extension of the stable model semantics to deal with new constructs called subjective literals. Informally speaking, a subjective literal allows checking whether some objective literal is true in all or some stable models. As it can be imagined, the associated semantics has proved to be non-trivial, since the truth of subjective literals may interfere with the set of stable models it is supposed to query. As a consequence, no clear agreement has been reached and different semantic proposals have been made in the literature. Unfortunately, comparison among these proposals has been limited to a study of their effect on individual examples, rather than identifying general properties to be checked. In this paper, we propose an extension of the well-known splitting property for logic programs to the epistemic case. We formally define when an arbitrary semantics satisfies the epistemic splitting property and examine some of the consequences that can be derived from that, including its relation to conformant planning and to epistemic constraints. Interestingly, we prove (through counterexamples) that most of the existing approaches fail to fulfill the epistemic splitting property, except the original semantics proposed by Gelfond 1991 and a recent proposal by the authors, called Founded Autoepistemic Equilibrium Logic.
KW  - knowledge representation and nonmonotonic reasoning
KW  - logic programming methodology and applications
KW  - theory
Y1  - 2021
U6  - https://doi.org/10.1017/S1471068420000058
SN  - 1471-0684
SN  - 1475-3081
VL  - 21
IS  - 3
SP  - 296
EP  - 316
PB  - Cambridge Univ. Press
CY  - Cambridge [u.a.]
ER  - 
TY  - GEN
A1  - Aguado, Felicidad
A1  - Cabalar, Pedro
A1  - Fandiño, Jorge
A1  - Pearce, David
A1  - Perez, Gilberto
A1  - Vidal, Concepcion
T1  - Revisiting explicit negation in answer set programming
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1104 
KW  - Answer Set Programming
KW  - non-monotonic reasoning
KW  - Equilibrium logic
KW  - explicit negation
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469697
SN  - 1866-8372
IS  - 1104
SP  - 908
EP  - 924
ER  - 
TY  - JOUR
A1  - Göbel, Andreas
A1  - Lagodzinski, Julius Albert Gregor
A1  - Seidel, Karen
T1  - Counting homomorphisms to trees modulo a prime
JF  - ACM transactions on computation theory : TOCT / Association for Computing Machinery
N2  - Many important graph-theoretic notions can be encoded as counting graph homomorphism problems, such as partition functions in statistical physics, in particular independent sets and colourings. In this article, we study the complexity of #(p) HOMSTOH, the problem of counting graph homomorphisms from an input graph to a graph H modulo a prime number p. Dyer and Greenhill proved a dichotomy stating that the tractability of non-modular counting graph homomorphisms depends on the structure of the target graph. Many intractable cases in non-modular counting become tractable in modular counting due to the common phenomenon of cancellation. In subsequent studies on counting modulo 2, however, the influence of the structure of H on the tractability was shown to persist, which yields similar dichotomies. <br /> Our main result states that for every tree H and every prime p the problem #pHOMSTOH is either polynomial time computable or #P-p-complete. This relates to the conjecture of Faben and Jerrum stating that this dichotomy holds for every graph H when counting modulo 2. In contrast to previous results on modular counting, the tractable cases of #pHOMSTOH are essentially the same for all values of the modulo when H is a tree. To prove this result, we study the structural properties of a homomorphism. As an important interim result, our study yields a dichotomy for the problem of counting weighted independent sets in a bipartite graph modulo some prime p. These results are the first suggesting that such dichotomies hold not only for the modulo 2 case but also for the modular counting functions of all primes p.
KW  - Graph homomorphisms
KW  - modular counting
KW  - complexity dichotomy
Y1  - 2021
U6  - https://doi.org/10.1145/3460958
SN  - 1942-3454
SN  - 1942-3462
VL  - 13
IS  - 3
SP  - 1
EP  - 33
PB  - Association for Computing Machinery
CY  - New York
ER  - 
TY  - THES
A1  - Taleb, Aiham
T1  - Self-supervised deep learning methods for medical image analysis
T1  - Selbstüberwachte Deep Learning Methoden für die medizinische Bildanalyse
N2  - Deep learning has seen widespread application in many domains, mainly for its ability to learn data representations from raw input data. Nevertheless, its success has so far been coupled with the availability of large annotated (labelled) datasets. This is a requirement that is difficult to fulfil in several domains, such as in medical imaging. Annotation costs form a barrier in extending deep learning to clinically-relevant use cases. The labels associated with medical images are scarce, since the generation of expert annotations of multimodal patient data at scale is non-trivial, expensive, and time-consuming. This substantiates the need for algorithms that learn from the increasing amounts of unlabeled data. Self-supervised representation learning algorithms offer a pertinent solution, as they allow solving real-world (downstream) deep learning tasks with fewer annotations. Self-supervised approaches leverage unlabeled samples to acquire generic features about different concepts, enabling annotation-efficient downstream task solving subsequently.
Nevertheless, medical images present multiple unique and inherent challenges for existing self-supervised learning approaches, which we seek to address in this thesis: (i) medical images are multimodal, and their multiple modalities are heterogeneous in nature and imbalanced in quantities, e.g. MRI and CT; (ii) medical scans are multi-dimensional, often in 3D instead of 2D; (iii) disease patterns in medical scans are numerous and their incidence exhibits a long-tail distribution, so it is oftentimes essential to fuse knowledge from different data modalities, e.g. genomics or clinical data, to capture disease traits more comprehensively; (iv) Medical scans usually exhibit more uniform color density distributions, e.g. in dental X-Rays, than natural images. Our proposed self-supervised methods meet these challenges, besides significantly reducing the amounts of required annotations.
We evaluate our self-supervised methods on a wide array of medical imaging applications and tasks. Our experimental results demonstrate the obtained gains in both annotation-efficiency and performance; our proposed methods outperform many approaches from related literature. Additionally, in case of fusion with genetic modalities, our methods also allow for cross-modal interpretability. In this thesis, not only we show that self-supervised learning is capable of mitigating manual annotation costs, but also our proposed solutions demonstrate how to better utilize it in the medical imaging domain. Progress in self-supervised learning has the potential to extend deep learning algorithms application to clinical scenarios.
N2  - Deep Learning findet in vielen Bereichen breite Anwendung, vor allem wegen seiner Fähigkeit, Datenrepräsentationen aus rohen Eingabedaten zu lernen. Dennoch war der Erfolg bisher an die Verfügbarkeit großer annotatierter Datensätze geknüpft. Dies ist eine Anforderung, die in verschiedenen Bereichen, z. B. in der medizinischen Bildgebung, schwer zu erfüllen ist. Die Kosten für die Annotation stellen ein Hindernis für die Ausweitung des Deep Learning auf klinisch relevante Anwendungsfälle dar. Die mit medizinischen Bildern verbundenen Annotationen sind rar, da die Erstellung von Experten Annotationen für multimodale Patientendaten in großem Umfang nicht trivial, teuer und zeitaufwändig ist. Dies unterstreicht den Bedarf an Algorithmen, die aus den wachsenden Mengen an unbeschrifteten Daten lernen. Selbstüberwachte Algorithmen für das Repräsentationslernen bieten eine mögliche Lösung, da sie die Lösung realer (nachgelagerter) Deep-Learning-Aufgaben mit weniger Annotationen ermöglichen. Selbstüberwachte Ansätze nutzen unannotierte Stichproben, um generisches Eigenschaften über verschiedene Konzepte zu erlangen und ermöglichen so eine annotationseffiziente Lösung nachgelagerter Aufgaben.
Medizinische Bilder stellen mehrere einzigartige und inhärente Herausforderungen für existierende selbstüberwachte Lernansätze dar, die wir in dieser Arbeit angehen wollen: (i) medizinische Bilder sind multimodal, und ihre verschiedenen Modalitäten sind von Natur aus heterogen und in ihren Mengen unausgewogen, z.B. (ii) medizinische Scans sind mehrdimensional, oft in 3D statt in 2D; (iii) Krankheitsmuster in medizinischen Scans sind zahlreich und ihre Häufigkeit weist eine Long-Tail-Verteilung auf, so dass es oft unerlässlich ist, Wissen aus verschiedenen Datenmodalitäten, z. B. Genomik oder klinische Daten, zu verschmelzen, um Krankheitsmerkmale umfassender zu erfassen; (iv) medizinische Scans weisen in der Regel eine gleichmäßigere Farbdichteverteilung auf, z. B. in zahnmedizinischen Röntgenaufnahmen, als natürliche Bilder. Die von uns vorgeschlagenen selbstüberwachten Methoden adressieren diese Herausforderungen und reduzieren zudem die Menge der erforderlichen Annotationen erheblich.
Wir evaluieren unsere selbstüberwachten Methoden in verschiedenen Anwendungen und Aufgaben der medizinischen Bildgebung. Unsere experimentellen Ergebnisse zeigen, dass die von uns vorgeschlagenen Methoden sowohl die Effizienz der Annotation als auch die Leistung steigern und viele Ansätze aus der verwandten Literatur übertreffen. Darüber hinaus ermöglichen unsere Methoden im Falle der Fusion mit genetischen Modalitäten auch eine modalübergreifende Interpretierbarkeit. In dieser Arbeit zeigen wir nicht nur, dass selbstüberwachtes Lernen in der Lage ist, die Kosten für manuelle Annotationen zu senken, sondern auch, wie man es in der medizinischen Bildgebung besser nutzen kann. Fortschritte beim selbstüberwachten Lernen haben das Potenzial, die Anwendung von Deep-Learning-Algorithmen auf klinische Szenarien auszuweiten.
KW  - Artificial Intelligence
KW  - machine learning
KW  - unsupervised learning
KW  - representation learning
KW  - Künstliche Intelligenz
KW  - maschinelles Lernen
KW  - Representationlernen
KW  - selbstüberwachtes Lernen
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-644089
ER  - 
TY  - JOUR
A1  - Taleb, Aiham
A1  - Rohrer, Csaba
A1  - Bergner, Benjamin
A1  - De Leon, Guilherme
A1  - Rodrigues, Jonas Almeida
A1  - Schwendicke, Falk
A1  - Lippert, Christoph
A1  - Krois, Joachim
T1  - Self-supervised learning methods for label-efficient dental caries classification
JF  - Diagnostics : open access journal
N2  - High annotation costs are a substantial bottleneck in applying deep learning architectures to clinically relevant use cases, substantiating the need for algorithms to learn from unlabeled data. 

In this work, we propose employing self-supervised methods. To that end, we trained with three self-supervised algorithms on a large corpus of unlabeled dental images, which contained 38K bitewing radiographs (BWRs). We then applied the learned neural network representations on tooth-level dental caries classification, for which we utilized labels extracted from electronic health records (EHRs). Finally, a holdout test-set was established, which consisted of 343 BWRs and was annotated by three dental professionals and approved by a senior dentist. 

This test-set was used to evaluate the fine-tuned caries classification models. Our experimental results demonstrate the obtained gains by pretraining models using self-supervised algorithms. These include improved caries classification performance (6 p.p. increase in sensitivity) and, most importantly, improved label-efficiency. 
In other words, the resulting models can be fine-tuned using few labels (annotations). 

Our results show that using as few as 18 annotations can produce >= 45% sensitivity, which is comparable to human-level diagnostic performance. 
This study shows that self-supervision can provide gains in medical image analysis, particularly when obtaining labels is costly and expensive.
KW  - unsupervised methods
KW  - self-supervised learning
KW  - representation learning
KW  - dental caries classification
KW  - data driven approaches
KW  - annotation
KW  - efficient deep learning
Y1  - 2022
U6  - https://doi.org/10.3390/diagnostics12051237
SN  - 2075-4418
VL  - 12
IS  - 5
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Vitagliano, Gerardo
A1  - Hameed, Mazhar
A1  - Jiang, Lan
A1  - Reisener, Lucas
A1  - Wu, Eugene
A1  - Naumann, Felix
T1  - Pollock: a data loading benchmark
JF  - Proceedings of the VLDB Endowment
N2  - Any system at play in a data-driven project has a fundamental requirement: the ability to load data. The de-facto standard format to distribute and consume raw data is CSV. Yet, the plain text and flexible nature of this format make such files often difficult to parse and correctly load their content, requiring cumbersome data preparation steps. We propose a benchmark to assess the robustness of systems in loading data from non-standard CSV formats and with structural inconsistencies. First, we formalize a model to describe the issues that affect real-world files and use it to derive a systematic lpollutionz process to generate dialects for any given grammar. Our benchmark leverages the pollution framework for the csv format. To guide pollution, we have surveyed thousands of real-world, publicly available csv files, recording the problems we encountered. We demonstrate the applicability of our benchmark by testing and scoring 16 different systems: popular csv parsing frameworks, relational database tools, spreadsheet systems, and a data visualization tool.
Y1  - 2023
U6  - https://doi.org/10.14778/3594512.3594518
SN  - 2150-8097
VL  - 16
IS  - 8
SP  - 1870
EP  - 1882
PB  - Association for Computing Machinery
CY  - New York
ER  - 
TY  - CHAP
A1  - Marx, Julian
A1  - Brünker, Felix
A1  - Mirbabaie, Milad
A1  - Stieglitz, Stefan
ED  - Bui, Tung X.
T1  - Digital activism on social media
BT  - the role of brand ambassadors and corporate reputation management
T2  - Proceedings of the 57th Annual Hawaii International Conference on System Sciences
N2  - Social media constitute an important arena for public debates and steady interchange of issues relevant to society. To boost their reputation, commercial organizations also engage in political, social, or environmental debates on social media. To engage in this type of digital activism, organizations increasingly utilize the social media profiles of executive employees and other brand ambassadors. However, the relationship between brand ambassadors’ digital activism and corporate reputation is only vaguely understood. The results of a qualitative inquiry suggest that digital activism via brand ambassadors can be risky (e.g., creating additional surface for firestorms, financial loss) and rewarding (e.g., emitting authenticity, employing ‘megaphones’ for industry change) at the same time. The paper informs both scholarship and practitioners about strategic trade-offs that need to be considered when employing brand ambassadors for digital activism.
KW  - the bright and dark side of social media in the marginalized contexts
KW  - brand ambassadors
KW  - digital activism
KW  - reputation management
KW  - social media
Y1  - 2024
UR  - https://hdl.handle.net/10125/107250
SN  - 978-0-99813-317-1
SP  - 7205
EP  - 7214
PB  - Department of IT Management Shidler College of Business University of Hawaii
CY  - Honolulu, HI
ER  - 
TY  - CHAP
A1  - Mirbabaie, Milad
A1  - Rieskamp, Jonas
A1  - Hofeditz, Lennart
A1  - Stieglitz, Stefan
ED  - Bui, Tung X.
T1  - Breaking down barriers
BT  - how conversational agents facilitate open science and data sharing
T2  - Proceedings of the 57th Annual Hawaii International Conference on System Sciences
N2  - Many researchers hesitate to provide full access to their datasets due to a lack of knowledge about research data management (RDM) tools and perceived fears, such as losing the value of one's own data. Existing tools and approaches often do not take into account these fears and missing knowledge. In this study, we examined how conversational agents (CAs) can provide a natural way of guidance through RDM processes and nudge researchers towards more data sharing. This work offers an online experiment in which researchers interacted with a CA on a self-developed RDM platform and a survey on participants’ data sharing behavior. Our findings indicate that the presence of a guiding and enlightening CA on an RDM platform has a constructive influence on both the intention to share data and the actual behavior of data sharing. Notably, individual factors do not appear to impede or hinder this effect.
KW  - open science practices in information systems research
KW  - conversational agents
KW  - data sharing
KW  - digital nudging
KW  - open science
KW  - research data management
Y1  - 2024
UR  - https://hdl.handle.net/10125/106457
SN  - 978-0-99813-317-1
SP  - 672
EP  - 681
PB  - Department of IT Management Shidler College of Business University of Hawaii
CY  - Honolulu, HI
ER  - 
TY  - JOUR
A1  - Nguyen, Dong Hai Phuong
A1  - Georgie, Yasmin Kim
A1  - Kayhan, Ezgi
A1  - Eppe, Manfred
A1  - Hafner, Verena Vanessa
A1  - Wermter, Stefan
T1  - Sensorimotor representation learning for an "active self" in robots
BT  - a model survey
JF  - Künstliche Intelligenz : KI ; Forschung, Entwicklung, Erfahrungen ; Organ des Fachbereichs 1 Künstliche Intelligenz der Gesellschaft für Informatik e.V., GI / Fachbereich 1 der Gesellschaft für Informatik e.V
N2  - Safe human-robot interactions require robots to be able to learn how to behave appropriately in spaces populated by people and thus to cope with the challenges posed by our dynamic and unstructured environment, rather than being provided a rigid set of rules for operations. In humans, these capabilities are thought to be related to our ability to perceive our body in space, sensing the location of our limbs during movement, being aware of other objects and agents, and controlling our body parts to interact with them intentionally. Toward the next generation of robots with bio-inspired capacities, in this paper, we first review the developmental processes of underlying mechanisms of these abilities: The sensory representations of body schema, peripersonal space, and the active self in humans. Second, we provide a survey of robotics models of these sensory representations and robotics models of the self; and we compare these models with the human counterparts. Finally, we analyze what is missing from these robotics models and propose a theoretical computational framework, which aims to allow the emergence of the sense of self in artificial agents by developing sensory representations through self-exploration.
KW  - Developmental robotics
KW  - Body schema
KW  - Peripersonal space
KW  - Agency
KW  - Robot learning
Y1  - 2021
U6  - https://doi.org/10.1007/s13218-021-00703-z
SN  - 0933-1875
SN  - 1610-1987
VL  - 35
IS  - 1
SP  - 9
EP  - 35
PB  - Springer
CY  - Berlin
ER  - 
TY  - THES
A1  - Huegle, Johannes
T1  - Causal discovery in practice: Non-parametric conditional independence testing and tooling for causal discovery
T1  - Kausale Entdeckung in der Praxis: Nichtparametrische bedingte Unabhängigkeitstests und Werkzeuge für die Kausalentdeckung
N2  - Knowledge about causal structures is crucial for decision support in various domains. For example, in discrete manufacturing, identifying the root causes of failures and quality deviations that interrupt the highly automated production process requires causal structural knowledge. However, in practice, root cause analysis is usually built upon individual expert knowledge about associative relationships. But, "correlation does not imply causation", and misinterpreting associations often leads to incorrect conclusions. Recent developments in methods for causal discovery from observational data have opened the opportunity for a data-driven examination. Despite its potential for data-driven decision support, omnipresent challenges impede causal discovery in real-world scenarios. In this thesis, we make a threefold contribution to improving causal discovery in practice.

(1) The growing interest in causal discovery has led to a broad spectrum of methods with specific assumptions on the data and various implementations. Hence, application in practice requires careful consideration of existing methods, which becomes laborious when dealing with various parameters, assumptions, and implementations in different programming languages. Additionally, evaluation is challenging due to the lack of ground truth in practice and limited benchmark data that reflect real-world data characteristics.
To address these issues, we present a platform-independent modular pipeline for causal discovery and a ground truth framework for synthetic data generation that provides comprehensive evaluation opportunities, e.g., to examine the accuracy of causal discovery methods in case of inappropriate assumptions.

(2) Applying constraint-based methods for causal discovery requires selecting a conditional independence (CI) test, which is particularly challenging in mixed discrete-continuous data omnipresent in many real-world scenarios. In this context, inappropriate assumptions on the data or the commonly applied discretization of continuous variables reduce the accuracy of CI decisions, leading to incorrect causal structures. 
Therefore, we contribute a non-parametric CI test leveraging k-nearest neighbors methods and prove its statistical validity and power in mixed discrete-continuous data, as well as the asymptotic consistency when used in constraint-based causal discovery. An extensive evaluation of synthetic and real-world data shows that the proposed CI test outperforms state-of-the-art approaches in the accuracy of CI testing and causal discovery, particularly in settings with low sample sizes. 

(3) To show the applicability and opportunities of causal discovery in practice, we examine our contributions in real-world discrete manufacturing use cases. For example, we showcase how causal structural knowledge helps to understand unforeseen production downtimes or adds decision support in case of failures and quality deviations in automotive body shop assembly lines.
N2  - Kenntnisse über die Strukturen zugrundeliegender kausaler Mechanismen sind eine Voraussetzung für die Entscheidungsunterstützung in verschiedenen Bereichen. In der Fertigungsindustrie beispielsweise erfordert die Fehler-Ursachen-Analyse von Störungen und Qualitätsabweichungen, die den hochautomatisierten Produktionsprozess unterbrechen, kausales Strukturwissen. In Praxis stützt sich die Fehler-Ursachen-Analyse in der Regel jedoch auf individuellem Expertenwissen über assoziative Zusammenhänge. Aber "Korrelation impliziert nicht Kausalität", und die Fehlinterpretation assoziativer Zusammenhänge führt häufig zu falschen Schlussfolgerungen. Neueste Entwicklungen von Methoden des kausalen Strukturlernens haben die Möglichkeit einer datenbasierten Betrachtung eröffnet. Trotz seines Potenzials zur datenbasierten Entscheidungsunterstützung wird das kausale Strukturlernen in der Praxis jedoch durch allgegenwärtige Herausforderungen erschwert. In dieser Dissertation leisten wir einen dreifachen Beitrag zur Verbesserung des kausalen Strukturlernens in der Praxis.

(1) Das wachsende Interesse an kausalem Strukturlernen hat zu einer Vielzahl von Methoden mit spezifischen statistischen Annahmen über die Daten und verschiedenen Implementierungen geführt. Daher erfordert die Anwendung in der Praxis eine sorgfältige Prüfung der vorhandenen Methoden, was eine Herausforderung darstellt, wenn verschiedene Parameter, Annahmen und Implementierungen in unterschiedlichen Programmiersprachen betrachtet werden. Hierbei wird die Evaluierung von Methoden des kausalen Strukturlernens zusätzlich durch das Fehlen von "Ground Truth" in der Praxis und begrenzten Benchmark-Daten, welche die Eigenschaften realer Datencharakteristiken widerspiegeln, erschwert.
Um diese Probleme zu adressieren, stellen wir eine plattformunabhängige modulare Pipeline für kausales Strukturlernen und ein Tool zur Generierung synthetischer Daten vor, die umfassende Evaluierungsmöglichkeiten bieten, z.B. um Ungenauigkeiten von Methoden des Lernens kausaler Strukturen bei falschen Annahmen an die Daten aufzuzeigen.

(2) Die Anwendung von constraint-basierten Methoden des kausalen Strukturlernens erfordert die Wahl eines bedingten Unabhängigkeitstests (CI-Test), was insbesondere bei gemischten diskreten und kontinuierlichen Daten, die in vielen realen Szenarien allgegenwärtig sind, die Anwendung erschwert. Beispielsweise führen falsche Annahmen der CI-Tests oder die Diskretisierung kontinuierlicher Variablen zu einer Verschlechterung der Korrektheit der Testentscheidungen, was in fehlerhaften kausalen Strukturen resultiert. 
Um diese Probleme zu adressieren, stellen wir einen nicht-parametrischen CI-Test vor, der auf Nächste-Nachbar-Methoden basiert, und beweisen dessen statistische Validität und Trennschärfe bei gemischten diskreten und kontinuierlichen Daten, sowie dessen asymptotische Konsistenz in constraint-basiertem kausalem Strukturlernen. Eine umfangreiche Evaluation auf synthetischen und realen Daten zeigt, dass der vorgeschlagene CI-Test bestehende Verfahren hinsichtlich der Korrektheit der Testentscheidung und gelernter kausaler Strukturen übertrifft, insbesondere bei geringen Stichprobengrößen. 

(3) Um die Anwendbarkeit und Möglichkeiten kausalen Strukturlernens in der Praxis aufzuzeigen, untersuchen wir unsere Beiträge in realen Anwendungsfällen aus der Fertigungsindustrie. Wir zeigen an mehreren Beispielen aus der automobilen Karosseriefertigungen wie kausales Strukturwissen helfen kann, unvorhergesehene Produktionsausfälle zu verstehen oder eine Entscheidungsunterstützung bei Störungen und Qualitätsabweichungen zu geben.
KW  - causal discovery
KW  - causal structure learning
KW  - causal AI
KW  - non-parametric conditional independence testing
KW  - manufacturing
KW  - causal reasoning
KW  - mixed data
KW  - kausale KI
KW  - kausale Entdeckung
KW  - kausale Schlussfolgerung
KW  - kausales Strukturlernen
KW  - Fertigung
KW  - gemischte Daten
KW  - nicht-parametrische bedingte Unabhängigkeitstests
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-635820
ER  - 
TY  - JOUR
A1  - Wiemker, Veronika
A1  - Bunova, Anna
A1  - Neufeld, Maria
A1  - Gornyi, Boris
A1  - Yurasova, Elena
A1  - Konigorski, Stefan
A1  - Kalinina, Anna
A1  - Kontsevaya, Anna
A1  - Ferreira-Borges, Carina
A1  - Probst, Charlotte
T1  - Pilot study to evaluate usability and acceptability of the 'Animated Alcohol Assessment Tool' in Russian primary healthcare
JF  - Digital health
N2  - Background and aims: Accurate and user-friendly assessment tools quantifying alcohol consumption are a prerequisite to effective prevention and treatment programmes, including Screening and Brief Intervention. Digital tools offer new potential in this field. We developed the ‘Animated Alcohol Assessment Tool’ (AAA-Tool), a mobile app providing an interactive version of the World Health Organization's Alcohol Use Disorders Identification Test (AUDIT) that facilitates the description of individual alcohol consumption via culturally informed animation features. This pilot study evaluated the Russia-specific version of the Animated Alcohol Assessment Tool with regard to (1) its usability and acceptability in a primary healthcare setting, (2) the plausibility of its alcohol consumption assessment results and (3) the adequacy of its Russia-specific vessel and beverage selection. Methods: Convenience samples of 55 patients (47% female) and 15 healthcare practitioners (80% female) in 2 Russian primary healthcare facilities self-administered the Animated Alcohol Assessment Tool and rated their experience on the Mobile Application Rating Scale – User Version. Usage data was automatically collected during app usage, and additional feedback on regional content was elicited in semi-structured interviews. Results: On average, patients completed the Animated Alcohol Assessment Tool in 6:38 min (SD = 2.49, range = 3.00–17.16). User satisfaction was good, with all subscale Mobile Application Rating Scale – User Version scores averaging >3 out of 5 points. A majority of patients (53%) and practitioners (93%) would recommend the tool to ‘many people’ or ‘everyone’. Assessed alcohol consumption was plausible, with a low number (14%) of logically impossible entries. Most patients reported the Animated Alcohol Assessment Tool to reflect all vessels (78%) and all beverages (71%) they typically used. Conclusion: High acceptability ratings by patients and healthcare practitioners, acceptable completion time, plausible alcohol usage assessment results and perceived adequacy of region-specific content underline the Animated Alcohol Assessment Tool's potential to provide a novel approach to alcohol assessment in primary healthcare. After its validation, the Animated Alcohol Assessment Tool might contribute to reducing alcohol-related harm by facilitating Screening and Brief Intervention implementation in Russia and beyond.
KW  - Alcohol use assessment
KW  - Alcohol Use Disorders Identification Test
KW  - screening tools
KW  - digital health
KW  - mobile applications
KW  - Russia
KW  - primary healthcare
KW  - usability
KW  - acceptability
Y1  - 2022
U6  - https://doi.org/10.1177/20552076211074491
SN  - 2055-2076
VL  - 8
PB  - Sage Publications
CY  - London
ER  - 
TY  - JOUR
A1  - Omranian, Sara
A1  - Angeleska, Angela
A1  - Nikoloski, Zoran
T1  - PC2P
BT  - parameter-free network-based prediction of protein complexes
JF  - Bioinformatics
N2  - Motivation: 
Prediction of protein complexes from protein-protein interaction (PPI) networks is an important problem in systems biology, as they control different cellular functions. The existing solutions employ algorithms for network community detection that identify dense subgraphs in PPI networks. However, gold standards in yeast and human indicate that protein complexes can also induce sparse subgraphs, introducing further challenges in protein complex prediction. 

Results: 
To address this issue, we formalize protein complexes as biclique spanned subgraphs, which include both sparse and dense subgraphs. We then cast the problem of protein complex prediction as a network partitioning into biclique spanned subgraphs with removal of minimum number of edges, called coherent partition. Since finding a coherent partition is a computationally intractable problem, we devise a parameter-free greedy approximation algorithm, termed Protein Complexes from Coherent Partition (PC2P), based on key properties of biclique spanned subgraphs. Through comparison with nine contenders, we demonstrate that PC2P: (i) successfully identifies modular structure in networks, as a prerequisite for protein complex prediction, (ii) outperforms the existing solutions with respect to a composite score of five performance measures on 75% and 100% of the analyzed PPI networks and gold standards in yeast and human, respectively, and (iii,iv) does not compromise GO semantic similarity and enrichment score of the predicted protein complexes. Therefore, our study demonstrates that clustering of networks in terms of biclique spanned subgraphs is a promising framework for detection of complexes in PPI networks.
Y1  - 2021
U6  - https://doi.org/10.1093/bioinformatics/btaa1089
SN  - 1367-4811
VL  - 37
IS  - 1
SP  - 73
EP  - 81
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - BOOK
A1  - Zhang, Shuhao
A1  - Plauth, Max
A1  - Eberhardt, Felix
A1  - Polze, Andreas
A1  - Lehmann, Jens
A1  - Sejdiu, Gezim
A1  - Jabeen, Hajira
A1  - Servadei, Lorenzo
A1  - Möstl, Christian
A1  - Bär, Florian
A1  - Netzeband, André
A1  - Schmidt, Rainer
A1  - Knigge, Marlene
A1  - Hecht, Sonja
A1  - Prifti, Loina
A1  - Krcmar, Helmut
A1  - Sapegin, Andrey
A1  - Jaeger, David
A1  - Cheng, Feng
A1  - Meinel, Christoph
A1  - Friedrich, Tobias
A1  - Rothenberger, Ralf
A1  - Sutton, Andrew M.
A1  - Sidorova, Julia A.
A1  - Lundberg, Lars
A1  - Rosander, Oliver
A1  - Sköld, Lars
A1  - Di Varano, Igor
A1  - van der Walt, Estée
A1  - Eloff, Jan H. P.
A1  - Fabian, Benjamin
A1  - Baumann, Annika
A1  - Ermakova, Tatiana
A1  - Kelkel, Stefan
A1  - Choudhary, Yash
A1  - Cooray, Thilini
A1  - Rodríguez, Jorge
A1  - Medina-Pérez, Miguel Angel
A1  - Trejo, Luis A.
A1  - Barrera-Animas, Ari Yair
A1  - Monroy-Borja, Raúl
A1  - López-Cuevas, Armando
A1  - Ramírez-Márquez, José Emmanuel
A1  - Grohmann, Maria
A1  - Niederleithinger, Ernst
A1  - Podapati, Sasidhar
A1  - Schmidt, Christopher
A1  - Huegle, Johannes
A1  - de Oliveira, Roberto C. L.
A1  - Soares, Fábio Mendes
A1  - van Hoorn, André
A1  - Neumer, Tamas
A1  - Willnecker, Felix
A1  - Wilhelm, Mathias
A1  - Kuster, Bernhard
ED  - Meinel, Christoph
ED  - Polze, Andreas
ED  - Beins, Karsten
ED  - Strotmann, Rolf
ED  - Seibold, Ulrich
ED  - Rödszus, Kurt
ED  - Müller, Jürgen
T1  - HPI Future SOC Lab – Proceedings 2017
T1  - HPI Future SOC Lab – Proceedings 2017
N2  - The “HPI Future SOC Lab” is a cooperation of the Hasso Plattner Institute (HPI) and industry partners. Its mission is to enable and promote exchange and interaction between the research community and the industry partners.
  The HPI Future SOC Lab provides researchers with free of charge access to a complete infrastructure of state of the art hard and software. This infrastructure includes components, which might be too expensive for an ordinary research environment, such as servers with up to 64 cores and 2 TB main memory. The offerings address researchers particularly from but not limited to the areas of computer science and business information systems. Main areas of research include cloud computing, parallelization, and In-Memory technologies.
  This technical report presents results of research projects executed in 2017. Selected projects have presented their results on April 25th and November 15th 2017 at the Future SOC Lab Day events.
N2  - Das Future SOC Lab am HPI ist eine Kooperation des Hasso-Plattner-Instituts mit verschiedenen Industriepartnern. Seine Aufgabe ist die Ermöglichung und Förderung des Austausches zwischen Forschungsgemeinschaft und Industrie.
  Am Lab wird interessierten Wissenschaftlern eine Infrastruktur von neuester Hard- und Software kostenfrei für Forschungszwecke zur Verfügung gestellt. Dazu zählen teilweise noch nicht am Markt verfügbare Technologien, die im normalen Hochschulbereich in der Regel nicht zu finanzieren wären, bspw. Server mit bis zu 64 Cores und 2 TB Hauptspeicher. Diese Angebote richten sich insbesondere an Wissenschaftler in den Gebieten Informatik und Wirtschaftsinformatik. Einige der Schwerpunkte sind Cloud Computing, Parallelisierung und In-Memory Technologien. 
  In diesem Technischen Bericht werden die Ergebnisse der Forschungsprojekte des Jahres 2017 vorgestellt.  Ausgewählte Projekte stellten ihre Ergebnisse am 25. April und 15. November 2017 im Rahmen der Future SOC Lab Tag Veranstaltungen vor.
T3  - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 130 
KW  - Future SOC Lab
KW  - research projects
KW  - multicore architectures
KW  - In-Memory technology
KW  - cloud computing
KW  - machine learning
KW  - artifical intelligence
KW  - Future SOC Lab
KW  - Forschungsprojekte
KW  - Multicore Architekturen
KW  - In-Memory Technologie
KW  - Cloud Computing
KW  - maschinelles Lernen
KW  - Künstliche Intelligenz
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-433100
SN  - 978-3-86956-475-3
SN  - 1613-5652
SN  - 2191-1665
IS  - 130
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Ulrich, Jens-Uwe
A1  - Lutfi, Ahmad
A1  - Rutzen, Kilian
A1  - Renard, Bernhard Y.
T1  - ReadBouncer
BT  - precise and scalable adaptive sampling for nanopore sequencing
JF  - Bioinformatics
N2  - Motivation: 
Nanopore sequencers allow targeted sequencing of interesting nucleotide sequences by rejecting other sequences from individual pores. This feature facilitates the enrichment of low-abundant sequences by depleting overrepresented ones in-silico. Existing tools for adaptive sampling either apply signal alignment, which cannot handle human-sized reference sequences, or apply read mapping in sequence space relying on fast graphical processing units (GPU) base callers for real-time read rejection. Using nanopore long-read mapping tools is also not optimal when mapping shorter reads as usually analyzed in adaptive sampling applications. 

Results: 
Here, we present a new approach for nanopore adaptive sampling that combines fast CPU and GPU base calling with read classification based on Interleaved Bloom Filters. ReadBouncer improves the potential enrichment of low abundance sequences by its high read classification sensitivity and specificity, outperforming existing tools in the field. It robustly removes even reads belonging to large reference sequences while running on commodity hardware without GPUs, making adaptive sampling accessible for in-field researchers. Readbouncer also provides a user-friendly interface and installer files for end-users without a bioinformatics background.
Y1  - 2022
U6  - https://doi.org/10.1093/bioinformatics/btac223
SN  - 1367-4803
SN  - 1367-4811
VL  - 38
IS  - SUPPL 1
SP  - 153
EP  - 160
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Wittig, Alice
A1  - Miranda, Fabio Malcher
A1  - Hölzer, Martin
A1  - Altenburg, Tom
A1  - Bartoszewicz, Jakub Maciej
A1  - Beyvers, Sebastian
A1  - Dieckmann, Marius Alfred
A1  - Genske, Ulrich
A1  - Giese, Sven Hans-Joachim
A1  - Nowicka, Melania
A1  - Richard, Hugues
A1  - Schiebenhoefer, Henning
A1  - Schmachtenberg, Anna-Juliane
A1  - Sieben, Paul
A1  - Tang, Ming
A1  - Tembrockhaus, Julius
A1  - Renard, Bernhard Y.
A1  - Fuchs, Stephan
T1  - CovRadar
BT  - continuously tracking and filtering SARS-CoV-2 mutations for genomic surveillance
JF  - Bioinformatics
N2  - The ongoing pandemic caused by SARS-CoV-2 emphasizes the importance of genomic surveillance to understand the evolution of the virus, to monitor the viral population, and plan epidemiological responses. Detailed analysis, easy visualization and intuitive filtering of the latest viral sequences are powerful for this purpose. We present CovRadar, a tool for genomic surveillance of the SARS-CoV-2 Spike protein. CovRadar consists of an analytical pipeline and a web application that enable the analysis and visualization of hundreds of thousand sequences. First, CovRadar extracts the regions of interest using local alignment, then builds a multiple sequence alignment, infers variants and consensus and finally presents the results in an interactive app, making accessing and reporting simple, flexible and fast.
Y1  - 2022
U6  - https://doi.org/10.1093/bioinformatics/btac411
SN  - 1367-4803
SN  - 1367-4811
VL  - 38
IS  - 17
SP  - 4223
EP  - 4225
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Trautmann, Justin
A1  - Zhou, Lin
A1  - Brahms, Clemens Markus
A1  - Tunca, Can
A1  - Ersoy, Cem
A1  - Granacher, Urs
A1  - Arnrich, Bert
T1  - TRIPOD
BT  - A treadmill walking dataset with IMU, pressure-distribution  and photoelectric data for gait analysis
JF  - Data : open access ʻData in scienceʼ journal
N2  - Inertial measurement units (IMUs) enable easy to operate and low-cost data recording for gait analysis. When combined with treadmill walking, a large number of steps can be collected in a controlled environment without the need of a dedicated gait analysis laboratory. In order to evaluate existing and novel IMU-based gait analysis algorithms for treadmill walking, a reference dataset that includes IMU data as well as reliable ground truth measurements for multiple participants and walking speeds is needed. This article provides a reference dataset consisting of 15 healthy young adults who walked on a treadmill at three different speeds. Data were acquired using seven IMUs placed on the lower body, two different reference systems (Zebris FDMT-HQ and OptoGait), and two RGB cameras. Additionally, in order to validate an existing IMU-based gait analysis algorithm using the dataset, an adaptable modular data analysis pipeline was built. Our results show agreement between the pressure-sensitive Zebris and the photoelectric OptoGait system (r = 0.99), demonstrating the quality of our reference data. As a use case, the performance of an algorithm originally designed for overground walking was tested on treadmill data using the data pipeline. The accuracy of stride length and stride time estimations was comparable to that reported in other studies with overground data, indicating that the algorithm is equally applicable to treadmill data. The Python source code of the data pipeline is publicly available, and the dataset will be provided by the authors upon request, enabling future evaluations of IMU gait analysis algorithms without the need of recording new data.
KW  - inertial measurement unit
KW  - gait analysis algorithm
KW  - OptoGait
KW  - Zebris
KW  - data pipeline
KW  - public dataset
Y1  - 2021
U6  - https://doi.org/10.3390/data6090095
SN  - 2306-5729
VL  - 6
IS  - 9
PB  - MDPI
CY  - Basel
ER  - 
TY  - THES
A1  - Videla, Santiago
T1  - Reasoning on the response of logical signaling networks with answer set programming
T1  - Modellierung Logischer Signalnetzwerke mittels Antwortmengenprogrammierung
N2  - Deciphering the functioning of biological networks is one of the central tasks in systems biology. In particular, signal transduction networks are crucial for the understanding of the cellular response to external and internal perturbations. Importantly, in order to cope with the complexity of these networks, mathematical and computational modeling is required. We propose a computational modeling framework in order to achieve more robust discoveries in the context of logical signaling networks. More precisely, we focus on modeling the response of logical signaling networks by means of automated reasoning using Answer Set Programming (ASP). ASP provides a declarative language for modeling various knowledge representation and reasoning problems. Moreover, available ASP solvers provide several reasoning modes for assessing the multitude of answer sets. Therefore, leveraging its rich modeling language and its highly efficient solving capacities, we use ASP to address three challenging problems in the context of logical signaling networks: learning of (Boolean) logical networks, experimental design, and identification of intervention strategies. Overall, the contribution of this thesis is three-fold. Firstly, we introduce a mathematical framework for characterizing and reasoning on the response of logical signaling networks. Secondly, we contribute to a growing list of successful applications of ASP in systems biology. Thirdly, we present a software providing a complete pipeline for automated reasoning on the response of logical signaling networks.
N2  - Deciphering the functioning of biological networks is one of the central tasks in systems biology. In particular, signal transduction networks are crucial for the understanding of the cellular response to external and internal perturbations. Importantly, in order to cope with the complexity of these networks, mathematical and computational modeling is required. We propose a computational modeling framework in order to achieve more robust discoveries in the context of logical signaling networks. More precisely, we focus on modeling the response of logical signaling networks by means of automated reasoning using Answer Set Programming (ASP). ASP provides a declarative language for modeling various knowledge representation and reasoning problems. Moreover, available ASP solvers provide several reasoning modes for assessing the multitude of answer sets. Therefore, leveraging its rich modeling language and its highly efficient solving capacities, we use ASP to address three challenging problems in the context of logical signaling networks: learning of (Boolean) logical networks, experimental design, and identification of intervention strategies. Overall, the contribution of this thesis is three-fold. Firstly, we introduce a mathematical framework for characterizing and reasoning on the response of logical signaling networks. Secondly, we contribute to a growing list of successful applications of ASP in systems biology. Thirdly, we present a software providing a complete pipeline for automated reasoning on the response of logical signaling networks.
KW  - Systembiologie
KW  - logische Signalnetzwerke
KW  - Antwortmengenprogrammierung
KW  - systems biology
KW  - logical signaling networks
KW  - answer set programming
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-71890
ER  - 
TY  - JOUR
A1  - Dimopoulos, Yannis
A1  - Gebser, Martin
A1  - Lühne, Patrick
A1  - Romero Davila, Javier
A1  - Schaub, Torsten
T1  - plasp 3
BT  - Towards Effective ASP Planning
JF  - Theory and practice of logic programming
N2  - 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.
KW  - knowledge representation and nonmonotonic reasoning
KW  - technical notes and rapid communications
KW  - answer set programming
KW  - automated planning
KW  - action and change
Y1  - 2019
U6  - https://doi.org/10.1017/S1471068418000583
SN  - 1471-0684
SN  - 1475-3081
VL  - 19
IS  - 3
SP  - 477
EP  - 504
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - THES
A1  - Konczak, Kathrin
T1  - Preferences in answer set programming
T1  - Präferenzen in der Antwortmengenprogrammierung
N2  - Answer Set Programming (ASP) emerged in the late 1990s as a new logic programming paradigm, having its roots in nonmonotonic reasoning, deductive databases, and logic programming with negation as failure. The basic idea of ASP is to represent a computational problem as a logic program whose answer sets correspond to solutions, and then to use an answer set solver for finding answer sets of the program. ASP is particularly suited for solving NP-complete search problems. Among these, we find applications to product configuration, diagnosis, and graph-theoretical problems, e.g. finding Hamiltonian cycles. On different lines of ASP research, many extensions of the basic formalism have been proposed. The most intensively studied one is the modelling of preferences in ASP. They constitute a natural and effective way of selecting preferred solutions among a plethora of solutions for a problem. For example, preferences have been successfully used for timetabling, auctioning, and product configuration. In this thesis, we concentrate on preferences within answer set programming. Among several formalisms and semantics for preference handling in ASP, we concentrate on ordered logic programs with the underlying D-, W-, and B-semantics. In this setting, preferences are defined among rules of a logic program. They select preferred answer sets among (standard) answer sets of the underlying logic program. Up to now, those preferred answer sets have been computed either via a compilation method or by meta-interpretation. Hence, the question comes up, whether and how preferences can be integrated into an existing ASP solver. To solve this question, we develop an operational graph-based framework for the computation of answer sets of logic programs. Then, we integrate preferences into this operational approach. We empirically observe that our integrative approach performs in most cases better than the compilation method or meta-interpretation. Another research issue in ASP are optimization methods that remove redundancies, as also found in database query optimizers. For these purposes, the rather recently suggested notion of strong equivalence for ASP can be used. If a program is strongly equivalent to a subprogram of itself, then one can always use the subprogram instead of the original program, a technique which serves as an effective optimization method. Up to now, strong equivalence has not been considered for logic programs with preferences. In this thesis, we tackle this issue and generalize the notion of strong equivalence to ordered logic programs. We give necessary and sufficient conditions for the strong equivalence of two ordered logic programs. Furthermore, we provide program transformations for ordered logic programs and show in how far preferences can be simplified. Finally, we present two new applications for preferences within answer set programming. First, we define new procedures for group decision making, which we apply to the problem of scheduling a group meeting. As a second new application, we reconstruct a linguistic problem appearing in German dialects within ASP. Regarding linguistic studies, there is an ongoing debate about how unique the rule systems of language are in human cognition. The reconstruction of grammatical regularities with tools from computer science has consequences for this debate: if grammars can be modelled this way, then they share core properties with other non-linguistic rule systems.
N2  - Die Antwortmengenprogrammierung entwickelte sich in den späten 90er Jahren als neues Paradigma der logischen Programmierung und ist in den Gebieten des nicht-monotonen Schließens und der deduktiven Datenbanken verwurzelt. Dabei wird eine Problemstellung als logisches Programm repräsentiert, dessen Lösungen, die so genannten Antwortmengen, genau den Lösungen des ursprünglichen Problems entsprechen. Die Antwortmengenprogrammierung bildet ein geeignetes Fundament zur Repräsentation und zum Lösen von Entscheidungs- und Suchproblemen in der Komplexitätsklasse NP. Anwendungen finden wir unter anderem in der Produktkonfiguration, Diagnose und bei graphen-theoretischen Problemen, z.B. der Suche nach Hamiltonschen Kreisen. In den letzten Jahren wurden viele Erweiterungen der Antwortmengenprogrammierung betrachtet. Die am meisten untersuchte Erweiterung ist die Modellierung von Präferenzen. Diese bilden eine natürliche und effektive Möglichkeit, unter einer Vielzahl von Lösungen eines Problems bevorzugte Lösungen zu selektieren. Präferenzen finden beispielsweise in der Stundenplanung, bei Auktionen und bei Produktkonfigurationen ihre Anwendung. Der Schwerpunkt dieser Arbeit liegt in der Modellierung, Implementierung und Anwendung von Präferenzen in der Antwortmengenprogrammierung. Da es verschiedene Ansätze gibt, um Präferenzen darzustellen, konzentrieren wir uns auf geordnete logische Programme, wobei Präferenzen als partielle Ordnung der Regeln eines logischen Programms ausgedrückt werden. Dabei betrachten wir drei verschiedene Semantiken zur Interpretation dieser Präferenzen. Im Vorfeld wurden für diese Semantiken die bevorzugten Antwortmengen durch einen Compiler oder durch Meta-Interpretation berechnet. Da Präferenzen Lösungen selektieren, stellt sich die Frage, ob es möglich ist, diese direkt in den Berechnungsprozeß von präferenzierten Antwortmengen zu integrieren, so dass die bevorzugten Antwortmengen ohne Zwischenschritte berechnet werden können. Dazu entwickeln wir zuerst ein auf Graphen basierendes Gerüst zur Berechnung von Antwortmengen. Anschließend werden wir darin Präferenzen integrieren, so dass bevorzugte Antwortmengen ohne Compiler oder Meta-Interpretation berechnet werden. Es stellt sich heraus, dass die integrative Methode auf den meisten betrachteten Problemklassen wesentlich leistungsfähiger ist als der Compiler oder Meta-Interpretation. Ein weiterer Schwerpunkt dieser Arbeit liegt in der Frage, inwieweit sich geordnete logische Programme vereinfachen lassen. Dazu steht die Methodik der strengen Äquivalenz von logischen Programmen zur Verfügung. Wenn ein logisches Programm streng äquivalent zu einem seiner Teilprogramme ist, so kann man dieses durch das entsprechende Teilprogramm ersetzen, ohne dass sich die zugrunde liegende Semantik ändert. Bisher wurden strenge Äquivalenzen nicht für logische Programme mit Präferenzen untersucht. In dieser Arbeit definieren wir erstmalig strenge Äquivalenzen für geordnete logische Programme. Wir geben notwendige und hinreichende Bedingungen für die strenge Äquivalenz zweier geordneter logischer Programme an. Des Weiteren werden wir auch die Frage beantworten, inwieweit geordnete logische Programme und deren Präferenzstrukturen vereinfacht werden können. Abschließend präsentieren wir zwei neue Anwendungsbereiche von Präferenzen in der Antwortmengenprogrammierung. Zuerst definieren wir neue Prozeduren zur Entscheidungsfindung innerhalb von Gruppenprozessen. Diese integrieren wir anschließend in das Problem der Planung eines Treffens für eine Gruppe. Als zweite neue Anwendung rekonstruieren wir mit Hilfe der Antwortmengenprogrammierung eine linguistische Problemstellung, die in deutschen Dialekten auftritt. Momentan wird im Bereich der Linguistik darüber diskutiert, ob Regelsysteme von (menschlichen) Sprachen einzigartig sind oder nicht. Die Rekonstruktion von grammatikalischen Regularitäten mit Werkzeugen aus der Informatik erlaubt die Unterstützung der These, dass linguistische Regelsysteme Gemeinsamkeiten zu anderen nicht-linguistischen Regelsystemen besitzen.
KW  - Präferenzen
KW  - Antwortmengenprogrammierung
KW  - logische Programmierung
KW  - Künstliche Intelligenz
KW  - preferences
KW  - priorities
KW  - answer set programming
KW  - logic programming
KW  - artificial intelligence
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12058
ER  - 
TY  - GEN
A1  - Lifschitz, Vladimir
A1  - Schaub, Torsten
A1  - Woltran, Stefan
T1  - Interview with Vladimir Lifschitz
T2  - Künstliche Intelligenz
N2  - 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.
Y1  - 2018
U6  - https://doi.org/10.1007/s13218-018-0552-x
SN  - 0933-1875
SN  - 1610-1987
VL  - 32
IS  - 2-3
SP  - 213
EP  - 218
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - CHAP
A1  - Dehnert, Maik
ED  - Buchmann, Robert Andrei
ED  - Polini, Andrea
ED  - Johansson, Björn
ED  - Karagiannis, Dimitris
T1  - Organizational change toward IT-supported personal advisory in incumbent banks
T2  - Perspectives in business informatics research
N2  - Due to changing customer behavior in digitalization, banks urge to change their traditional value creation in order to improve interaction with customers. New digital technologies such as core banking solutions change organizational structures to provide organizational and individual affordances in IT-supported personal advisory. Based on adaptive structuration theory and with qualitative data from 24 German banks, we identify first, second and third order issues of organizational change in value creation, which are connected with a set of affordances and constraints as the outcomes for customer interaction.
Y1  - 2020
SN  - 978-3-030-61139-2
SN  - 978-3-030-61140-8
U6  - https://doi.org/10.1007/978-3-030-61140-8_14
VL  - 398
SP  - 205
EP  - 219
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Dehnert, Maik
A1  - Gleiß, Alexander
A1  - Reiss, Frederick
T1  - What makes a data-driven business model?
BT  - a consolidated taxonomy
T2  - ECIS Proceedings 2021
N2  - The usage of data to improve or create business models has become vital for companies in the 21st century. However, to extract value from data it is important to understand the business model. Taxonomies for data-driven business models (DDBM) aim to provide guidance for the development and ideation of new business models relying on data. In IS research, however, different taxonomies have emerged in recent years, partly redundant, partly contradictory. Thus, there is a need to synthesize the common ground of these taxonomies within IS research. Based on 26 IS-related taxonomies and 30 cases, we derive and define 14 generic building blocks of DDBM to develop a consolidated taxonomy that represents the current state-of-the-art. Thus, we integrate existing research on DDBM and provide avenues for further exploration of data-induced potentials for business models as well as for the development and analysis of general or industry-specific DDBM.
Y1  - 2021
UR  - https://aisel.aisnet.org/ecis2021_rp/139
SN  - 978-1-7336325-6-0
PB  - AIS
CY  - Atlanta
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaminski, Roland
A1  - Kaufmann, Benjamin
A1  - Lühne, Patrick
A1  - Obermeier, Philipp
A1  - Ostrowski, Max
A1  - Romero Davila, Javier
A1  - Schaub, Torsten
A1  - Schellhorn, Sebastian
A1  - Wanko, Philipp
T1  - The Potsdam Answer Set Solving Collection 5.0
JF  - Künstliche Intelligenz
N2  - 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.
Y1  - 2018
U6  - https://doi.org/10.1007/s13218-018-0528-x
SN  - 0933-1875
SN  - 1610-1987
VL  - 32
IS  - 2-3
SP  - 181
EP  - 182
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Haubelt, Christian
A1  - Neubauer, Kai
A1  - Schaub, Torsten
A1  - Wanko, Philipp
T1  - Design space exploration with answer set programming
JF  - Künstliche Intelligenz
N2  - 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.
Y1  - 2018
U6  - https://doi.org/10.1007/s13218-018-0530-3
SN  - 0933-1875
SN  - 1610-1987
VL  - 32
IS  - 2-3
SP  - 205
EP  - 206
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - BOOK
A1  - Meinel, Christoph
A1  - Döllner, Jürgen Roland Friedrich
A1  - Weske, Mathias
A1  - Polze, Andreas
A1  - Hirschfeld, Robert
A1  - Naumann, Felix
A1  - Giese, Holger
A1  - Baudisch, Patrick
A1  - Friedrich, Tobias
A1  - Böttinger, Erwin
A1  - Lippert, Christoph
A1  - Dörr, Christian
A1  - Lehmann, Anja
A1  - Renard, Bernhard
A1  - Rabl, Tilmann
A1  - Uebernickel, Falk
A1  - Arnrich, Bert
A1  - Hölzle, Katharina
T1  - Proceedings of the HPI Research School on Service-oriented Systems Engineering 2020 Fall Retreat
N2  - Design and Implementation of service-oriented architectures imposes a huge number of research questions from the fields of software engineering, system analysis and modeling, adaptability, and application integration. Component orientation and web services are two approaches for design and realization of complex web-based system. Both approaches allow for dynamic application adaptation as well as integration of enterprise application.

Service-Oriented Systems Engineering represents a symbiosis of best practices in object-orientation, component-based development, distributed computing, and business process management. It provides integration of business and IT concerns.

The annual Ph.D. Retreat of the Research School provides each member the opportunity to present his/her current state of their research and to give an outline of a prospective Ph.D. thesis. Due to the interdisciplinary structure of the research school, this technical report covers a wide range of topics. These include but are not limited to: Human Computer Interaction and Computer Vision as Service; Service-oriented Geovisualization Systems; Algorithm Engineering for Service-oriented Systems; Modeling and Verification of Self-adaptive Service-oriented Systems; Tools and Methods for Software Engineering in Service-oriented Systems; Security Engineering of Service-based IT Systems; Service-oriented Information Systems; Evolutionary Transition of Enterprise Applications to Service Orientation; Operating System Abstractions for Service-oriented Computing; and Services Specification, Composition, and Enactment.
N2  - Der Entwurf und die Realisierung dienstbasierender Architekturen wirft eine Vielzahl von Forschungsfragestellungen aus den Gebieten der Softwaretechnik, der Systemmodellierung und -analyse, sowie der Adaptierbarkeit und Integration von Applikationen auf. Komponentenorientierung und WebServices sind zwei Ansätze für den effizienten Entwurf und die Realisierung komplexer Web-basierender Systeme. Sie ermöglichen die Reaktion auf wechselnde Anforderungen ebenso, wie die Integration großer komplexer Softwaresysteme.

"Service-Oriented Systems Engineering" repräsentiert die Symbiose bewährter Praktiken aus den Gebieten der Objektorientierung, der Komponentenprogrammierung, des verteilten Rechnen sowie der Geschäftsprozesse und berücksichtigt auch die Integration von Geschäftsanliegen und Informationstechnologien.

Die Klausurtagung des Forschungskollegs "Service-oriented Systems Engineering" findet einmal jährlich statt und bietet allen Kollegiaten die Möglichkeit den Stand ihrer aktuellen Forschung darzulegen. Bedingt durch die Querschnittstruktur des Kollegs deckt dieser Bericht ein weites Spektrum aktueller Forschungsthemen ab. Dazu zählen unter anderem Human Computer Interaction and Computer Vision as Service; Service-oriented Geovisualization Systems; Algorithm Engineering for Service-oriented Systems; Modeling and Verification of Self-adaptive Service-oriented Systems; Tools and Methods for Software Engineering in Service-oriented Systems; Security Engineering of Service-based IT Systems; Service-oriented Information Systems; Evolutionary Transition of Enterprise Applications to Service Orientation; Operating System Abstractions for Service-oriented Computing; sowie Services Specification, Composition, and Enactment.
T3  - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 138 
KW  - Hasso Plattner Institute
KW  - research school
KW  - Ph.D. retreat
KW  - service-oriented systems engineering
KW  - Hasso-Plattner-Institut
KW  - Forschungskolleg
KW  - Klausurtagung
KW  - Service-oriented Systems Engineering
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-504132
SN  - 978-3-86956-513-2
SN  - 1613-5652
SN  - 2191-1665
IS  - 138
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Richly, Keven
A1  - Schlosser, Rainer
A1  - Boissier, Martin
T1  - Budget-conscious fine-grained configuration optimization for spatio-temporal applications
JF  - Proceedings of the VLDB Endowment
N2  - Based on the performance requirements of modern spatio-temporal data mining applications, in-memory database systems are often used to store and process the data. To efficiently utilize the scarce DRAM capacities, modern database systems support various tuning possibilities to reduce the memory footprint (e.g., data compression) or increase performance (e.g., additional indexes). However, the selection of cost and performance balancing configurations is challenging due to the vast number of possible setups consisting of mutually dependent individual decisions. In this paper, we introduce a novel approach to jointly optimize the compression, sorting, indexing, and tiering configuration for spatio-temporal workloads. Further, we consider horizontal data partitioning, which enables the independent application of different tuning options on a fine-grained level. We propose different linear programming (LP) models addressing cost dependencies at different levels of accuracy to compute optimized tuning configurations for a given workload and memory budgets. To yield maintainable and robust configurations, we extend our LP-based approach to incorporate reconfiguration costs as well as a worst-case optimization for potential workload scenarios. Further, we demonstrate on a real-world dataset that our models allow to significantly reduce the memory footprint with equal performance or increase the performance with equal memory size compared to existing tuning heuristics.
KW  - General Earth and Planetary Sciences
KW  - Water Science and Technology
KW  - Geography, Planning and Development
Y1  - 2022
U6  - https://doi.org/10.14778/3565838.3565858
SN  - 2150-8097
VL  - 15
IS  - 13
SP  - 4079
EP  - 4092
PB  - Association for Computing Machinery (ACM)
CY  - [New York]
ER  - 
TY  - GEN
A1  - Monti, Remo
A1  - Rautenstrauch, Pia
A1  - Ghanbari, Mahsa
A1  - James, Alva Rani
A1  - Kirchler, Matthias
A1  - Ohler, Uwe
A1  - Konigorski, Stefan
A1  - Lippert, Christoph
T1  - Identifying interpretable gene-biomarker associations with functionally informed kernel-based tests in 190,000 exomes
T2  - Zweitveröffentlichungen der Universität Potsdam : Reihe der Digital Engineering Fakultät
N2  - Here we present an exome-wide rare genetic variant association study for 30 blood biomarkers in 191,971 individuals in the UK Biobank. We compare gene- based association tests for separate functional variant categories to increase interpretability and identify 193 significant gene-biomarker associations. Genes associated with biomarkers were ~ 4.5-fold enriched for conferring Mendelian disorders. In addition to performing weighted gene-based variant collapsing tests, we design and apply variant-category-specific kernel-based tests that integrate quantitative functional variant effect predictions for mis- sense variants, splicing and the binding of RNA-binding proteins. For these tests, we present a computationally efficient combination of the likelihood- ratio and score tests that found 36% more associations than the score test alone while also controlling the type-1 error. Kernel-based tests identified 13% more associations than their gene-based collapsing counterparts and had advantages in the presence of gain of function missense variants. We introduce local collapsing by amino acid position for missense variants and use it to interpret associations and identify potential novel gain of function variants in PIEZO1. Our results show the benefits of investigating different functional mechanisms when performing rare-variant association tests, and demonstrate pervasive rare-variant contribution to biomarker variability.
T3  - Zweitveröffentlichungen der Universität Potsdam : Reihe der Digital Engineering Fakultät - 16 
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-586078
IS  - 16
ER  - 
TY  - JOUR
A1  - Monti, Remo
A1  - Rautenstrauch, Pia
A1  - Ghanbari, Mahsa
A1  - James, Alva Rani
A1  - Kirchler, Matthias
A1  - Ohler, Uwe
A1  - Konigorski, Stefan
A1  - Lippert, Christoph
T1  - Identifying interpretable gene-biomarker associations with functionally informed kernel-based tests in 190,000 exomes
JF  - Nature Communications
N2  - Here we present an exome-wide rare genetic variant association study for 30 blood biomarkers in 191,971 individuals in the UK Biobank. We compare gene- based association tests for separate functional variant categories to increase interpretability and identify 193 significant gene-biomarker associations. Genes associated with biomarkers were ~ 4.5-fold enriched for conferring Mendelian disorders. In addition to performing weighted gene-based variant collapsing tests, we design and apply variant-category-specific kernel-based tests that integrate quantitative functional variant effect predictions for mis- sense variants, splicing and the binding of RNA-binding proteins. For these tests, we present a computationally efficient combination of the likelihood- ratio and score tests that found 36% more associations than the score test alone while also controlling the type-1 error. Kernel-based tests identified 13% more associations than their gene-based collapsing counterparts and had advantages in the presence of gain of function missense variants. We introduce local collapsing by amino acid position for missense variants and use it to interpret associations and identify potential novel gain of function variants in PIEZO1. Our results show the benefits of investigating different functional mechanisms when performing rare-variant association tests, and demonstrate pervasive rare-variant contribution to biomarker variability.
Y1  - 2022
U6  - https://doi.org/10.1038/s41467-022-32864-2
SN  - 2041-1723
VL  - 13
PB  - Nature Publishing Group UK
CY  - London
ER  - 
TY  - BOOK
A1  - Juiz, Carlos
A1  - Bermejo, Belen
A1  - Calle, Alejandro
A1  - Sidorova, Julia
A1  - Lundberg, Lars
A1  - Weidmann, Vera
A1  - Lowitzki, Leon
A1  - Mirtschin, Marvin
A1  - Hoorn, André van
A1  - Frank, Markus
A1  - Schulz, Henning
A1  - Stojanovic, Dragan
A1  - Stojanovic, Natalija
A1  - Stojnev Ilic, Aleksandra
A1  - Friedrich, Tobias
A1  - Lenzner, Pascal
A1  - Weyand, Christopher
A1  - Wagner, Markus
A1  - Plauth, Max
A1  - Polze, Andreas
A1  - Nowicki, Marek
A1  - Seth, Sugandh
A1  - Kaur Chahal, Kuljit
A1  - Singh, Gurwinder
A1  - Speth, Sandro
A1  - Janes, Andrea
A1  - Camilli, Matteo
A1  - Ziegler, Erik
A1  - Schmidberger, Marcel
A1  - Pörschke, Mats
A1  - Bartz, Christian
A1  - Lorenz, Martin
A1  - Meinel, Christoph
A1  - Beilich, Robert
A1  - Bertazioli, Dario
A1  - Carlomagno, Cristiano
A1  - Bedoni, Marzia
A1  - Messina, Vincenzina
ED  - Meinel, Christoph
ED  - Polze, Andreas
ED  - Beins, Karsten
ED  - Strotmann, Rolf
ED  - Seibold, Ulrich
ED  - Rödszus, Kurt
ED  - Müller, Jürgen
ED  - Sommer, Jürgen
T1  - HPI Future SOC Lab
BT  - Proceedings 2020
T3  - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam
N2  - The “HPI Future SOC Lab” is a cooperation of the Hasso Plattner Institute (HPI) and industry partners. Its mission is to enable and promote exchange and interaction between the research community and the industry partners.
The HPI Future SOC Lab provides researchers with free of charge access to a complete infrastructure of state of the art hard and software. This infrastructure includes components, which might be too expensive for an ordinary research environment, such as servers with up to 64 cores and 2 TB main memory. The offerings address researchers particularly from but not limited to the areas of computer science and business information systems. Main areas of research include cloud computing, parallelization, and In-Memory technologies.
This technical report presents results of research projects executed in 2020. Selected projects have presented their results on April 21st and November 10th 2020 at the Future SOC Lab Day events.
N2  - Das Future SOC Lab am HPI ist eine Kooperation des Hasso-Plattner-Instituts mit verschiedenen Industriepartnern. Seine Aufgabe ist die Ermöglichung und Förderung des Austausches zwischen Forschungsgemeinschaft und Industrie.
Am Lab wird interessierten Wissenschaftlern eine Infrastruktur von neuester Hard- und Software kostenfrei für Forschungszwecke zur Verfügung gestellt. Dazu zählen teilweise noch nicht am Markt verfügbare Technologien, die im normalen Hochschulbereich in der Regel nicht zu finanzieren wären, bspw. Server mit bis zu 64 Cores und 2 TB Hauptspeicher. Diese Angebote richten sich insbesondere an Wissenschaftler in den Gebieten Informatik und Wirtschaftsinformatik. Einige der Schwerpunkte sind Cloud Computing, Parallelisierung und In-Memory Technologien. 
In diesem Technischen Bericht werden die Ergebnisse der Forschungsprojekte des Jahres 2020 vorgestellt.  Ausgewählte Projekte stellten ihre Ergebnisse am 21. April und 10. November 2020 im Rahmen des Future SOC Lab Tags vor.
T3  - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 159 
KW  - Future SOC Lab
KW  - research projects
KW  - multicore architectures
KW  - in-memory technology
KW  - cloud computing
KW  - machine learning
KW  - artifical intelligence
KW  - Future SOC Lab
KW  - Forschungsprojekte
KW  - Multicore Architekturen
KW  - In-Memory Technologie
KW  - Cloud Computing
KW  - maschinelles Lernen
KW  - künstliche Intelligenz
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-598014
SN  - 978-3-86956-565-1
SN  - 1613-5652
SN  - 2191-1665
IS  - 159
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - BOOK
A1  - Kuban, Robert
A1  - Rotta, Randolf
A1  - Nolte, Jörg
A1  - Chromik, Jonas
A1  - Beilharz, Jossekin Jakob
A1  - Pirl, Lukas
A1  - Friedrich, Tobias
A1  - Lenzner, Pascal
A1  - Weyand, Christopher
A1  - Juiz, Carlos
A1  - Bermejo, Belen
A1  - Sauer, Joao
A1  - Coelh, Leandro dos Santos
A1  - Najafi, Pejman
A1  - Pünter, Wenzel
A1  - Cheng, Feng
A1  - Meinel, Christoph
A1  - Sidorova, Julia
A1  - Lundberg, Lars
A1  - Vogel, Thomas
A1  - Tran, Chinh
A1  - Moser, Irene
A1  - Grunske, Lars
A1  - Elsaid, Mohamed Esameldin Mohamed
A1  - Abbas, Hazem M.
A1  - Rula, Anisa
A1  - Sejdiu, Gezim
A1  - Maurino, Andrea
A1  - Schmidt, Christopher
A1  - Hügle, Johannes
A1  - Uflacker, Matthias
A1  - Nozza, Debora
A1  - Messina, Enza
A1  - Hoorn, André van
A1  - Frank, Markus
A1  - Schulz, Henning
A1  - Alhosseini Almodarresi Yasin, Seyed Ali
A1  - Nowicki, Marek
A1  - Muite, Benson K.
A1  - Boysan, Mehmet Can
A1  - Bianchi, Federico
A1  - Cremaschi, Marco
A1  - Moussa, Rim
A1  - Abdel-Karim, Benjamin M.
A1  - Pfeuffer, Nicolas
A1  - Hinz, Oliver
A1  - Plauth, Max
A1  - Polze, Andreas
A1  - Huo, Da
A1  - Melo, Gerard de
A1  - Mendes Soares, Fábio
A1  - Oliveira, Roberto Célio Limão de
A1  - Benson, Lawrence
A1  - Paul, Fabian
A1  - Werling, Christian
A1  - Windheuser, Fabian
A1  - Stojanovic, Dragan
A1  - Djordjevic, Igor
A1  - Stojanovic, Natalija
A1  - Stojnev Ilic, Aleksandra
A1  - Weidmann, Vera
A1  - Lowitzki, Leon
A1  - Wagner, Markus
A1  - Ifa, Abdessatar Ben
A1  - Arlos, Patrik
A1  - Megia, Ana
A1  - Vendrell, Joan
A1  - Pfitzner, Bjarne
A1  - Redondo, Alberto
A1  - Ríos Insua, David
A1  - Albert, Justin Amadeus
A1  - Zhou, Lin
A1  - Arnrich, Bert
A1  - Szabó, Ildikó
A1  - Fodor, Szabina
A1  - Ternai, Katalin
A1  - Bhowmik, Rajarshi
A1  - Campero Durand, Gabriel
A1  - Shevchenko, Pavlo
A1  - Malysheva, Milena
A1  - Prymak, Ivan
A1  - Saake, Gunter
ED  - Meinel, Christoph
ED  - Polze, Andreas
ED  - Beins, Karsten
ED  - Strotmann, Rolf
ED  - Seibold, Ulrich
ED  - Rödszus, Kurt
ED  - Müller, Jürgen
T1  - HPI Future SOC Lab – Proceedings 2019
N2  - The “HPI Future SOC Lab” is a cooperation of the Hasso Plattner Institute (HPI) and industry partners. Its mission is to enable and promote exchange and interaction between the research community and the industry partners.
  The HPI Future SOC Lab provides researchers with free of charge access to a complete infrastructure of state of the art hard and software. This infrastructure includes components, which might be too expensive for an ordinary research environment, such as servers with up to 64 cores and 2 TB main memory. The offerings address researchers particularly from but not limited to the areas of computer science and business information systems. Main areas of research include cloud computing, parallelization, and In-Memory technologies.
  This technical report presents results of research projects executed in 2019. Selected projects have presented their results on April 9th and November 12th 2019 at the Future SOC Lab Day events.
N2  - Das Future SOC Lab am HPI ist eine Kooperation des Hasso-Plattner-Instituts mit verschiedenen Industriepartnern. Seine Aufgabe ist die Ermöglichung und Förderung des Austausches zwischen Forschungsgemeinschaft und Industrie.
  Am Lab wird interessierten Wissenschaftlern eine Infrastruktur von neuester Hard- und Software kostenfrei für Forschungszwecke zur Verfügung gestellt. Dazu zählen teilweise noch nicht am Markt verfügbare Technologien, die im normalen Hochschulbereich in der Regel nicht zu finanzieren wären, bspw. Server mit bis zu 64 Cores und 2 TB Hauptspeicher. Diese Angebote richten sich insbesondere an Wissenschaftler in den Gebieten Informatik und Wirtschaftsinformatik. Einige der Schwerpunkte sind Cloud Computing, Parallelisierung und In-Memory Technologien. 
  In diesem Technischen Bericht werden die Ergebnisse der Forschungsprojekte des Jahres 2019 vorgestellt.  Ausgewählte Projekte stellten ihre Ergebnisse am 09. April und 12. November 2019 im Rahmen des Future SOC Lab Tags vor.
T3  - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 158 
KW  - Future SOC Lab
KW  - research projects
KW  - multicore architectures
KW  - in-memory technology
KW  - cloud computing
KW  - machine learning
KW  - artifical intelligence
KW  - Future SOC Lab
KW  - Forschungsprojekte
KW  - Multicore Architekturen
KW  - In-Memory Technologie
KW  - Cloud Computing
KW  - maschinelles Lernen
KW  - künstliche Intelligenz
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-597915
SN  - 978-3-86956-564-4
SN  - 1613-5652
SN  - 2191-1665
IS  - 158
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - THES
A1  - Mayer, Selina
T1  - Understanding the impact of design thinking on organizations and individuals
N2  - Organizations are investing billions on innovation and agility initiatives to stay competitive in their increasingly uncertain business environments. Design Thinking, an innovation approach based on human-centered exploration, ideation and experimentation, has gained increasing popularity. The market for Design Thinking, including software products and general services, is projected to reach 2.500 million $ (US-Dollar) by 2028. A dispersed set of positive outcomes have been attributed to Design Thinking. However, there is no clear understanding of what exactly comprises the impact of Design Thinking and how it is created. To support a billion-dollar market, it is essential to understand the value Design Thinking is bringing to organizations not only to justify large investments, but to continuously improve the approach and its application.
Following a qualitative research approach combined with results from a systematic literature review, the results presented in this dissertation offer a structured understanding of Design Thinking impact. The results are structured along two main perspectives of impact: the individual and the organizational perspective. First, insights from qualitative data analysis demonstrate that measuring and assessing the impact of Design Thinking is currently one central challenge for Design Thinking practitioners in organizations. Second, the interview data revealed several effects Design Thinking has on individuals, demonstrating how Design Thinking can impact boundary management behaviors and enable employees to craft their jobs more actively.
Contributing to innovation management research, the work presented in this dissertation systematically explains the Design Thinking impact, allowing other researchers to both locate and integrate their work better. The results of this research advance the theoretical rigor of Design Thinking impact research, offering multiple theoretical underpinnings explaining the variety of Design Thinking impact. Furthermore, this dissertation contains three specific propositions on how Design Thinking creates an impact: Design Thinking creates an impact through integration, enablement, and engagement. Integration refers to how Design Thinking enables organizations through effectively combining things, such as for example fostering balance between exploitation and exploration activities. Through Engagement, Design Thinking impacts organizations involving users and other relevant stakeholders in their work. Moreover, Design Thinking creates impact through Enablement, making it possible for individuals to enact a specific behavior or experience certain states.
By synthesizing multiple theoretical streams into these three overarching themes, the results of this research can help bridge disciplinary boundaries, for example between business, psychology and design, and enhance future collaborative research. Practitioners benefit from the results as multiple desirable outcomes are detailed in this thesis, such as successful individual job crafting behaviors, which can be expected from practicing Design Thinking. This allows practitioners to enact more evidence-based decision-making concerning Design Thinking implementation. Overall, considering multiple levels of impact as well as a broad range of theoretical underpinnings are paramount to understanding and fostering Design Thinking impact.
N2  - Unternehmen geben Milliarden für Innovations- und Agilitätsinitiativen aus. Sie wenden zunehmend agile und innovative Ansätze an, um komplexe Probleme zu erkunden und zu lösen. So stellen sie ihre Wettbewerbsfähigkeit sicher, da das heutige Geschäftsumfeld immer unsicherer und mehrdeutiger wird. Design Thinking ist ein immer beliebter werdender Innovationsansatz, der auf menschenzentrierter Erkundung, Ideenfindung und Experimenten basiert. Marktforschungen schätzen, dass der Design Thinking-Markt, einschließlich Softwareprodukten und allgemeinen Dienstleistungen, bis 2028 ein Volumen von 2,5 Milliarden US-Dollar erreichen wird. Zwar wurden Design Thinking vereinzelt positive Ergebnisse zugeschrieben (z. B. bessere Identifizierung von Kundenbedürfnissen, höhere Innovationsfähigkeiten, bessere Innovationsergebnisse), doch gibt es kein klares Verständnis darüber, was genau die Wirkung und den Mehrwert von Design Thinking ausmacht und wie diese Wirkung entsteht. Um einen Milliardenmarkt zu erhalten und zu rechtfertigen, ist es wichtig zu verstehen, welchen Wert Design Thinking für Unternehmen bringt. Dabei kommt es nicht nur darauf an, hohe Investitionen zu rechtfertigen, sondern auch darauf, den Ansatz und seine Einsatzgebiete kontinuierlich zu verbessern.
Basierend auf qualitativen Interviewdaten und einer systematischen Literaturrecherche bietet diese Dissertation ein strukturiertes Verständnis der Wirkung von Design Thinking an. Die Ergebnisse sind entlang zweier Hauptwirkungsperspektiven gegliedert, der individuellen und der organisationalen Perspektive. Erstens zeigen Erkenntnisse aus der qualitativen Datenanalyse, dass die Messung und Bewertung der Auswirkungen von Design Thinking derzeit eine zentrale Herausforderung für Design Thinking-Praktiker in Organisationen darstellt. Zweitens zeigten die Interviewdaten mehrere Auswirkungen, die Design Thinking auf Einzelpersonen hat. Im Detail zeig die Arbeit, wie Design Thinking es MitarbeiterInnen ermöglich, ihre Grenzen zu managenen (= „Boundary Management“ zu betreiben), oder, auch, wie sie durch sogennantes „Job Crafting“ ihre Arbeit aktiv gestalten können. 
Als Beitrag zur Innovationsmanagementforschung erläutert diese Dissertation systematisch die Auswirkungen von Design Thinking und ermöglicht es anderen Forschern, ihre Arbeit besser zu lokalisieren und zu integrieren. Die Ergebnisse dieser Forschung erweitern die theoretische Integration der Design Thinking-Forschung und bieten mehrere theoretische Grundlagen, die die Vielfalt der Design Thinking-Wirkung erklären. Darüber hinaus schlägt diese Dissertation drei konkrete Thesen vor, wie Design Thinking Wirkung erzeugt: Design Thinking erzeugt Wirkung durch Integration, Enablement und Engagement. Integration bezieht sich darauf, wie Design Thinking Organisationen durch die effektive Kombination von Dingen unterstützt, beispielsweise durch die Förderung eines Gleichgewichts zwischen Exploration und Exploitation im Sinne der Ambidextrie. Durch Engagement wirkt sich Design Thinking auf Organisationen aus, die Benutzer und andere relevante Stakeholder in ihre Arbeit einbeziehen. Und Design Thinking erzeugt durch Enablement Wirkung und ermöglicht es Einzelpersonen, ein bestimmtes Verhalten auszuführen oder bestimmte Zustände zu erleben.
Durch die Zusammenfassung mehrerer theoretischer Strömungen zu diesen drei übergreifenden Themen können die Ergebnisse dieser Forschung dazu beitragen, disziplinäre Grenzen, beispielsweise zwischen Wirtschaft, Psychologie und Design, zu überbrücken und zukünftige gemeinsame Forschung zu verbessern.
Praktiker profitieren von den Ergebnissen, da diese Arbeit Ergebnisse detailliert beschreibt, die von zukünftigen Design Thinking-Aktivitäten erwartet werden können, sodass Praktiker eine evidenzbasiertere Entscheidung hinsichtlich der Design Thinking-Implementierung treffen können.
Insgesamt ist die Berücksichtigung mehrerer Wirkungsebenen sowie einer breiten Palette theoretischer Grundlagen von größter Bedeutung, um die Wirkung von Design Thinking zu verstehen und zu fördern.
T2  - Die Auswirkungen von Design Thinking auf Organisationen und Individuen
KW  - Design Thinking
KW  - Impact
KW  - Grounded Theory
KW  - Theoretical Foundations
KW  - Design Thinking
KW  - Grounded Theory
KW  - Auswirkungen
KW  - theoretische Grundlagen
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-651541
ER  - 
TY  - JOUR
A1  - Wright, Michelle F.
A1  - Wachs, Sebastian
T1  - Moderation of technology use in the association between self-isolation during COVID-19 pandemic and adolescents' romantic relationship quality
JF  - Cyberpsychology, behavior and social networking
N2  - The purpose of this study was to examine the moderating effects of technology use for relationship maintenance on the longitudinal associations among self-isolation during the coronavirus-19 (COVID-19) pandemic and romantic relationship quality among adolescents. Participants were 239 (120 female; M age = 16.69, standard deviation [SD] = 0.61; 60 percent Caucasian) 11th and 12th graders from three midwestern high schools. To qualify for this study, adolescents had to be in the same romantic relationship for the duration of the study, similar to 7 months (M length of relationship = 10.03 months). Data were collected in October of 2019 (Time 1) and again 7 months later in May of 2020 (Time 2). Adolescents completed a romantic relationship questionnaire at Time 1 and again at Time 2, along with questionnaires on frequency of self-isolation during the COVID-19 pandemic and use of technology for romantic relationship maintenance. Findings revealed that increases in self-isolation during the COVID-19 pandemic related positively to the use of technology for romantic relationship maintenance and negatively to Time 2 romantic relationship quality. High use of technology for romantic relationship maintenance buffered against the negative effects of self-isolation during the COVID-19 pandemic on adolescents' romantic relationship quality 7 months later, whereas low use strengthened the negative relationship between self-isolation during the COVID-19 pandemic and romantic relationship quality. These findings suggest the importance of considering the implications of societal crisis or pandemics on adolescents' close relationships, particularly their romantic relationships.
KW  - romantic relationship
KW  - COVID-19
KW  - coronavirus
KW  - technology
KW  - romantic
KW  - relationship quality
KW  - adolescent
Y1  - 2021
U6  - https://doi.org/10.1089/cyber.2020.0729
SN  - 2152-2715
SN  - 2152-2723
VL  - 24
IS  - 7
SP  - 493
EP  - 498
PB  - Liebert
CY  - New Rochelle
ER  - 
TY  - BOOK
A1  - Adriano, Christian
A1  - Bleifuß, Tobias
A1  - Cheng, Lung-Pan
A1  - Diba, Kiarash
A1  - Fricke, Andreas
A1  - Grapentin, Andreas
A1  - Jiang, Lan
A1  - Kovacs, Robert
A1  - Krejca, Martin Stefan
A1  - Mandal, Sankalita
A1  - Marwecki, Sebastian
A1  - Matthies, Christoph
A1  - Mattis, Toni
A1  - Niephaus, Fabio
A1  - Pirl, Lukas
A1  - Quinzan, Francesco
A1  - Ramson, Stefan
A1  - Rezaei, Mina
A1  - Risch, Julian
A1  - Rothenberger, Ralf
A1  - Roumen, Thijs
A1  - Stojanovic, Vladeta
A1  - Wolf, Johannes
ED  - Meinel, Christoph
ED  - Plattner, Hasso
ED  - Döllner, Jürgen Roland Friedrich
ED  - Weske, Mathias
ED  - Polze, Andreas
ED  - Hirschfeld, Robert
ED  - Naumann, Felix
ED  - Giese, Holger
ED  - Baudisch, Patrick
ED  - Friedrich, Tobias
ED  - Böttinger, Erwin
ED  - Lippert, Christoph
T1  - Technical report
BT  - Fall Retreat 2018
N2  - Design and Implementation of service-oriented architectures imposes a huge number of research questions from the fields of software engineering, system analysis and modeling, adaptability, and application integration. Component orientation and web services are two approaches for design and realization of complex web-based system. Both approaches allow for dynamic application adaptation as well as integration of enterprise application.

Commonly used technologies, such as J2EE and .NET, form de facto standards for the realization of complex distributed systems. Evolution of component systems has lead to web services and service-based architectures. This has been manifested in a multitude of industry standards and initiatives such as XML, WSDL UDDI, SOAP, etc. All these achievements lead to a new and promising paradigm in IT systems engineering which proposes to design complex software solutions as collaboration of contractually defined software services.

Service-Oriented Systems Engineering represents a symbiosis of best practices in object-orientation, component-based development, distributed computing, and business process management. It provides integration of business and IT concerns.

The annual Ph.D. Retreat of the Research School provides each member the opportunity to present his/her current state of their research and to give an outline of a prospective Ph.D. thesis. Due to the interdisciplinary structure of the research school, this technical report covers a wide range of topics. These include but are not limited to: Human Computer Interaction and Computer Vision as Service; Service-oriented Geovisualization Systems; Algorithm Engineering for Service-oriented Systems; Modeling and Verification of Self-adaptive Service-oriented Systems; Tools and Methods for Software Engineering in Service-oriented Systems; Security Engineering of Service-based IT Systems; Service-oriented Information Systems; Evolutionary Transition of Enterprise Applications to Service Orientation; Operating System Abstractions for Service-oriented Computing; and Services Specification, Composition, and Enactment.
N2  - Der Entwurf und die Realisierung dienstbasierender Architekturen wirft eine Vielzahl von Forschungsfragestellungen aus den Gebieten der Softwaretechnik, der Systemmodellierung und -analyse, sowie der Adaptierbarkeit und Integration von Applikationen auf. Komponentenorientierung und WebServices sind zwei Ansätze für den effizienten Entwurf und die Realisierung komplexer Web-basierender Systeme. Sie ermöglichen die Reaktion auf wechselnde Anforderungen ebenso, wie die Integration großer komplexer Softwaresysteme.

Heute übliche Technologien, wie J2EE und .NET, sind de facto Standards für die Entwicklung großer verteilter Systeme. Die Evolution solcher Komponentensysteme führt über WebServices zu dienstbasierenden Architekturen. Dies manifestiert sich in einer Vielzahl von Industriestandards und Initiativen wie XML, WSDL, UDDI, SOAP. All diese Schritte führen letztlich zu einem neuen, vielversprechenden Paradigma für IT Systeme, nach dem komplexe Softwarelösungen durch die Integration vertraglich vereinbarter Software-Dienste aufgebaut werden sollen.

"Service-Oriented Systems Engineering" repräsentiert die Symbiose bewährter Praktiken aus den Gebieten der Objektorientierung, der Komponentenprogrammierung, des verteilten Rechnen sowie der Geschäftsprozesse und berücksichtigt auch die Integration von Geschäftsanliegen und Informationstechnologien.

Die Klausurtagung des Forschungskollegs "Service-oriented Systems Engineering" findet einmal jährlich statt und bietet allen Kollegiaten die Möglichkeit den Stand ihrer aktuellen Forschung darzulegen. Bedingt durch die Querschnittstruktur des Kollegs deckt dieser Bericht ein weites Spektrum aktueller Forschungsthemen ab. Dazu zählen unter anderem Human Computer Interaction and Computer Vision as Service; Service-oriented Geovisualization Systems; Algorithm Engineering for Service-oriented Systems; Modeling and Verification of Self-adaptive Service-oriented Systems; Tools and Methods for Software Engineering in Service-oriented Systems; Security Engineering of Service-based IT Systems; Service-oriented Information Systems; Evolutionary Transition of Enterprise Applications to Service Orientation; Operating System Abstractions for Service-oriented Computing; sowie Services Specification, Composition, and Enactment.
T3  - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 129 
KW  - Hasso Plattner Institute
KW  - research school
KW  - Ph.D. retreat
KW  - service-oriented systems engineering
KW  - Hasso-Plattner-Institut
KW  - Forschungskolleg
KW  - Klausurtagung
KW  - Service-oriented Systems Engineering
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427535
SN  - 978-3-86956-465-4
SN  - 1613-5652
SN  - 2191-1665
IS  - 129
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Yadav, Himanshu
A1  - Husain, Samar
A1  - Futrell, Richard
T1  - Assessing corpus evidence for formal and psycholinguistic constraints on nonprojectivity
JF  - Computational linguistics
N2  - Formal constraints on crossing dependencies have played a large role in research on the formal complexity of natural language grammars and parsing. Here we ask whether the apparent evidence for constraints on crossing dependencies in treebanks might arise because of independent constraints on trees, such as low arity and dependency length minimization. We address this question using two sets of experiments. In Experiment 1, we compare the distribution of formal properties of crossing dependencies, such as gap degree, between real trees and baseline trees matched for rate of crossing dependencies and various other properties. In Experiment 2, we model whether two dependencies cross, given certain psycholinguistic properties of the dependencies. We find surprisingly weak evidence for constraints originating from the mild context-sensitivity literature (gap degree and well-nestedness) beyond what can be explained by constraints on rate of crossing dependencies, topological properties of the trees, and dependency length. However, measures that have emerged from the parsing literature (e.g., edge degree, end-point crossings, and heads' depth difference) differ strongly between real and random trees. Modeling results show that cognitive metrics relating to information locality and working-memory limitations affect whether two dependencies cross or not, but they do not fully explain the distribution of crossing dependencies in natural languages. Together these results suggest that crossing constraints are better characterized by processing pressures than by mildly context-sensitive constraints.
Y1  - 2022
U6  - https://doi.org/10.1162/coli_a_00437
SN  - 0891-2017
SN  - 1530-9312
VL  - 48
IS  - 2
SP  - 375
EP  - 401
PB  - MIT Press
CY  - Cambridge
ER  -