@article{XuRazaghiMoghadamNikoloski2021,
author = {Xu, Rudan and Razaghi-Moghadam, Zahra and Nikoloski, Zoran},
title = {Maximization of non-idle enzymes improves the coverage of the estimated maximal in vivo enzyme catalytic rates in Escherichia coli},
series = {Bioinformatics},
volume = {37},
journal = {Bioinformatics},
number = {21},
publisher = {Oxford Univ. Press},
address = {Oxford},
issn = {1367-4803},
doi = {10.1093/bioinformatics/btab575},
pages = {3848 -- 3855},
year = {2021},
abstract = {Motivation: Constraint-based modeling approaches allow the estimation of maximal in vivo enzyme catalytic rates that can serve as proxies for enzyme turnover numbers. Yet, genome-scale flux profiling remains a challenge in deploying these approaches to catalogue proxies for enzyme catalytic rates across organisms. Results: Here, we formulate a constraint-based approach, termed NIDLE-flux, to estimate fluxes at a genome-scale level by using the principle of efficient usage of expressed enzymes. Using proteomics data from Escherichia coli, we show that the fluxes estimated by NIDLE-flux and the existing approaches are in excellent qualitative agreement (Pearson correlation > 0.9). We also find that the maximal in vivo catalytic rates estimated by NIDLE-flux exhibits a Pearson correlation of 0.74 with in vitro enzyme turnover numbers. However, NIDLE-flux results in a 1.4-fold increase in the size of the estimated maximal in vivo catalytic rates in comparison to the contenders. Integration of the maximum in vivo catalytic rates with publically available proteomics and metabolomics data provide a better match to fluxes estimated by NIDLE-flux. Therefore, NIDLE-flux facilitates more effective usage of proteomics data to estimate proxies for kcatomes.},
language = {en}
}
@phdthesis{Wolf2021,
author = {Wolf, Johannes},
title = {Analysis and visualization of transport infrastructure based on large-scale geospatial mobile mapping data},
doi = {10.25932/publishup-53612},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-536129},
school = {Universit{\"a}t Potsdam},
pages = {vi, 121},
year = {2021},
abstract = {3D point clouds are a universal and discrete digital representation of three-dimensional objects and environments. For geospatial applications, 3D point clouds have become a fundamental type of raw data acquired and generated using various methods and techniques. In particular, 3D point clouds serve as raw data for creating digital twins of the built environment. This thesis concentrates on the research and development of concepts, methods, and techniques for preprocessing, semantically enriching, analyzing, and visualizing 3D point clouds for applications around transport infrastructure. It introduces a collection of preprocessing techniques that aim to harmonize raw 3D point cloud data, such as point density reduction and scan profile detection. Metrics such as, e.g., local density, verticality, and planarity are calculated for later use. One of the key contributions tackles the problem of analyzing and deriving semantic information in 3D point clouds. Three different approaches are investigated: a geometric analysis, a machine learning approach operating on synthetically generated 2D images, and a machine learning approach operating on 3D point clouds without intermediate representation. In the first application case, 2D image classification is applied and evaluated for mobile mapping data focusing on road networks to derive road marking vector data. The second application case investigates how 3D point clouds can be merged with ground-penetrating radar data for a combined visualization and to automatically identify atypical areas in the data. For example, the approach detects pavement regions with developing potholes. The third application case explores the combination of a 3D environment based on 3D point clouds with panoramic imagery to improve visual representation and the detection of 3D objects such as traffic signs. The presented methods were implemented and tested based on software frameworks for 3D point clouds and 3D visualization. In particular, modules for metric computation, classification procedures, and visualization techniques were integrated into a modular pipeline-based C++ research framework for geospatial data processing, extended by Python machine learning scripts. All visualization and analysis techniques scale to large real-world datasets such as road networks of entire cities or railroad networks. The thesis shows that some use cases allow taking advantage of established image vision methods to analyze images rendered from mobile mapping data efficiently. The two presented semantic classification methods working directly on 3D point clouds are use case independent and show similar overall accuracy when compared to each other. While the geometry-based method requires less computation time, the machine learning-based method supports arbitrary semantic classes but requires training the network with ground truth data. Both methods can be used in combination to gradually build this ground truth with manual corrections via a respective annotation tool. This thesis contributes results for IT system engineering of applications, systems, and services that require spatial digital twins of transport infrastructure such as road networks and railroad networks based on 3D point clouds as raw data. It demonstrates the feasibility of fully automated data flows that map captured 3D point clouds to semantically classified models. This provides a key component for seamlessly integrated spatial digital twins in IT solutions that require up-to-date, object-based, and semantically enriched information about the built environment.},
language = {en}
}
@phdthesis{Weise2021,
author = {Weise, Matthias},
title = {Auswahl von Selektions- und Manipulationstechniken f{\"u}r Virtual Reality-Anwendungen},
doi = {10.25932/publishup-53458},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-534586},
school = {Universit{\"a}t Potsdam},
pages = {iii, 218},
year = {2021},
abstract = {Die stetige Weiterentwicklung von VR-Systemen bietet neue M{\"o}glichkeiten der Interaktion mit virtuellen Objekten im dreidimensionalen Raum, stellt Entwickelnde von VRAnwendungen aber auch vor neue Herausforderungen. Selektions- und Manipulationstechniken m{\"u}ssen unter Ber{\"u}cksichtigung des Anwendungsszenarios, der Zielgruppe und der zur Verf{\"u}gung stehenden Ein- und Ausgabeger{\"a}te ausgew{\"a}hlt werden. Diese Arbeit leistet einen Beitrag dazu, die Auswahl von passenden Interaktionstechniken zu unterst{\"u}tzen. Hierf{\"u}r wurde eine repr{\"a}sentative Menge von Selektions- und Manipulationstechniken untersucht und, unter Ber{\"u}cksichtigung existierender Klassifikationssysteme, eine Taxonomie entwickelt, die die Analyse der Techniken hinsichtlich interaktionsrelevanter Eigenschaften erm{\"o}glicht. Auf Basis dieser Taxonomie wurden Techniken ausgew{\"a}hlt, die in einer explorativen Studie verglichen wurden, um R{\"u}ckschl{\"u}sse auf die Dimensionen der Taxonomie zu ziehen und neue Indizien f{\"u}r Vor- und Nachteile der Techniken in spezifischen Anwendungsszenarien zu generieren. Die Ergebnisse der Arbeit m{\"u}nden in eine Webanwendung, die Entwickelnde von VR-Anwendungen gezielt dabei unterst{\"u}tzt, passende Selektions- und Manipulationstechniken f{\"u}r ein Anwendungsszenario auszuw{\"a}hlen, indem Techniken auf Basis der Taxonomie gefiltert und unter Verwendung der Resultate aus der Studie sortiert werden k{\"o}nnen.},
language = {de}
}
@article{vonSteinauSteinrueckJoeris2021,
author = {von Steinau-Steinr{\"u}ck, Robert and J{\"o}ris, Nils},
title = {Brexit-Arbeitsrecht und die Folgen},
series = {NJW spezial},
volume = {18},
journal = {NJW spezial},
number = {8},
publisher = {C.H. Beck},
address = {M{\"u}nchen},
issn = {1613-4621},
pages = {242 -- 243},
year = {2021},
abstract = {Die Corona-Pandemie hat den Brexit ein wenig in den Hintergrund gedr{\"a}ngt. Dabei hat er gerade im Arbeitsrecht ganz erhebliche Auswirkungen. {\"U}ber sie geben wir einen {\"U}berblick.},
language = {de}
}
@article{vonSteinauSteinrueckBruhn2021,
author = {von Steinau-Steinr{\"u}ck, Robert and Bruhn, Emma},
title = {Der Impfmuffel im Arbeitsrecht},
series = {NJW spezial},
volume = {18},
journal = {NJW spezial},
number = {16},
publisher = {C.H. Beck},
address = {M{\"u}nchen},
issn = {1613-4621},
pages = {498 -- 499},
year = {2021},
abstract = {Trotz erfolgreicher Impfkampagne droht nach dem Sommer eine vierte Infektionswelle der Corona-Pandemie. Ob es dazu kommen wird, h{\"a}ngt maßgeblich davon ab, wie viele Menschen sich f{\"u}r eine Corona-Schutzimpfung entscheiden. Am Impfstoff mangelt es nicht mehr, daf{\"u}r an der Impfbereitschaft. Viele Arbeitgeber fragen sich daher, was sie unternehmen k{\"o}nnen, um die Impfquote in ihren Betrieben zu erh{\"o}hen.},
language = {de}
}
@article{vonSteinauSteinrueck2021,
author = {von Steinau-Steinr{\"u}ck, Robert},
title = {Was ist bei "Workation" und "Bleisure" rechtlich zu beachten?},
series = {NJW spezial},
volume = {18},
journal = {NJW spezial},
number = {20},
publisher = {C.H. Beck},
address = {M{\"u}nchen},
issn = {1613-4621},
pages = {626 -- 627},
year = {2021},
abstract = {Die Digitalisierung unseres Lebens l{\"o}st die Grenzen zwischen Privat- und Berufsleben immer weiter auf. Bekanntes Beispiel ist das Homeoffice. Arbeitgeber begegnen aber auch zahlreichen weiteren Trends in diesem Zusammenhang. Dazu geh{\"o}ren „workation", also die Verbindung zwischen Arbeit („work") und Urlaub („vacation") ebenso wie „bleisure", dh die Verbindung von Dienstreisen („business") und Urlaub („leisure"). Der Beitrag geht den rechtlichen Rahmenbedingungen hierf{\"u}r nach.},
language = {de}
}
@article{VitaglianoJiangNaumann2021,
author = {Vitagliano, Gerardo and Jiang, Lan and Naumann, Felix},
title = {Detecting layout templates in complex multiregion files},
series = {Proceedings of the VLDB Endowment},
volume = {15},
journal = {Proceedings of the VLDB Endowment},
number = {3},
publisher = {Association for Computing Machinery},
address = {New York},
issn = {2150-8097},
doi = {10.14778/3494124.3494145},
pages = {646 -- 658},
year = {2021},
abstract = {Spreadsheets are among the most commonly used file formats for data management, distribution, and analysis. Their widespread employment makes it easy to gather large collections of data, but their flexible canvas-based structure makes automated analysis difficult without heavy preparation. One of the common problems that practitioners face is the presence of multiple, independent regions in a single spreadsheet, possibly separated by repeated empty cells. We define such files as "multiregion" files. In collections of various spreadsheets, we can observe that some share the same layout. We present the Mondrian approach to automatically identify layout templates across multiple files and systematically extract the corresponding regions. Our approach is composed of three phases: first, each file is rendered as an image and inspected for elements that could form regions; then, using a clustering algorithm, the identified elements are grouped to form regions; finally, every file layout is represented as a graph and compared with others to find layout templates. We compare our method to state-of-the-art table recognition algorithms on two corpora of real-world enterprise spreadsheets. Our approach shows the best performances in detecting reliable region boundaries within each file and can correctly identify recurring layouts across files.},
language = {en}
}
@article{UllrichTeichmannGronau2021,
author = {Ullrich, Andr{\´e} and Teichmann, Malte and Gronau, Norbert},
title = {Fast trainable capabilities in software engineering-skill development in learning factories},
series = {Ji suan ji jiao yu = Computer Education / Qing hua da xue},
journal = {Ji suan ji jiao yu = Computer Education / Qing hua da xue},
number = {12},
publisher = {[Verlag nicht ermittelbar]},
address = {Bei jing shi},
issn = {1672-5913},
doi = {10.16512/j.cnki.jsjjy.2020.12.002},
pages = {2 -- 10},
year = {2021},
abstract = {The increasing demand for software engineers cannot completely be fulfilled by university education and conventional training approaches due to limited capacities. Accordingly, an alternative approach is necessary where potential software engineers are being educated in software engineering skills using new methods. We suggest micro tasks combined with theoretical lessons to overcome existing skill deficits and acquire fast trainable capabilities. This paper addresses the gap between demand and supply of software engineers by introducing an actionoriented and scenario-based didactical approach, which enables non-computer scientists to code. Therein, the learning content is provided in small tasks and embedded in learning factory scenarios. Therefore, different requirements for software engineers from the market side and from an academic viewpoint are analyzed and synthesized into an integrated, yet condensed skills catalogue. This enables the development of training and education units that focus on the most important skills demanded on the market. To achieve this objective, individual learning scenarios are developed. Of course, proper basic skills in coding cannot be learned over night but software programming is also no sorcery.},
language = {en}
}
@article{TrautmannZhouBrahmsetal.2021,
author = {Trautmann, Justin and Zhou, Lin and Brahms, Clemens Markus and Tunca, Can and Ersoy, Cem and Granacher, Urs and Arnrich, Bert},
title = {TRIPOD},
series = {Data : open access ʻData in scienceʼ journal},
volume = {6},
journal = {Data : open access ʻData in scienceʼ journal},
number = {9},
publisher = {MDPI},
address = {Basel},
issn = {2306-5729},
doi = {10.3390/data6090095},
pages = {19},
year = {2021},
abstract = {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.},
language = {en}
}
@phdthesis{TorcatoMordido2021,
author = {Torcato Mordido, Gon{\c{c}}alo Filipe},
title = {Diversification, compression, and evaluation methods for generative adversarial networks},
doi = {10.25932/publishup-53546},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-535460},
school = {Universit{\"a}t Potsdam},
pages = {xiii, 148},
year = {2021},
abstract = {Generative adversarial networks (GANs) have been broadly applied to a wide range of application domains since their proposal. In this thesis, we propose several methods that aim to tackle different existing problems in GANs. Particularly, even though GANs are generally able to generate high-quality samples, the diversity of the generated set is often sub-optimal. Moreover, the common increase of the number of models in the original GANs framework, as well as their architectural sizes, introduces additional costs. Additionally, even though challenging, the proper evaluation of a generated set is an important direction to ultimately improve the generation process in GANs. We start by introducing two diversification methods that extend the original GANs framework to multiple adversaries to stimulate sample diversity in a generated set. Then, we introduce a new post-training compression method based on Monte Carlo methods and importance sampling to quantize and prune the weights and activations of pre-trained neural networks without any additional training. The previous method may be used to reduce the memory and computational costs introduced by increasing the number of models in the original GANs framework. Moreover, we use a similar procedure to quantize and prune gradients during training, which also reduces the communication costs between different workers in a distributed training setting. We introduce several topology-based evaluation methods to assess data generation in different settings, namely image generation and language generation. Our methods retrieve both single-valued and double-valued metrics, which, given a real set, may be used to broadly assess a generated set or separately evaluate sample quality and sample diversity, respectively. Moreover, two of our metrics use locality-sensitive hashing to accurately assess the generated sets of highly compressed GANs. The analysis of the compression effects in GANs paves the way for their efficient employment in real-world applications. Given their general applicability, the methods proposed in this thesis may be extended beyond the context of GANs. Hence, they may be generally applied to enhance existing neural networks and, in particular, generative frameworks.},
language = {en}
}
@article{TavakoliAlirezazadehHedayatipouretal.2021,
author = {Tavakoli, Hamad and Alirezazadeh, Pendar and Hedayatipour, Ava and Nasib, A. H. Banijamali and Landwehr, Niels},
title = {Leaf image-based classification of some common bean cultivars using discriminative convolutional neural networks},
series = {Computers and electronics in agriculture : COMPAG online ; an international journal},
volume = {181},
journal = {Computers and electronics in agriculture : COMPAG online ; an international journal},
publisher = {Elsevier},
address = {Amsterdam [u.a.]},
issn = {0168-1699},
doi = {10.1016/j.compag.2020.105935},
pages = {11},
year = {2021},
abstract = {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.},
language = {en}
}
@article{Steinroetter2021,
author = {Steinr{\"o}tter, Bj{\"o}rn},
title = {Das Konzept einer datenaltruistischen Organisation},
series = {Datenschutz und Datensicherheit},
volume = {45},
journal = {Datenschutz und Datensicherheit},
number = {12},
publisher = {Springer},
address = {Berlin},
issn = {1862-2607},
doi = {10.1007/s11623-021-1539-6},
pages = {794 -- 798},
year = {2021},
abstract = {Dass Technologien wie Machine Learning-Anwendungen oder Big bzw. Smart Data- Verfahren unbedingt Daten in ausreichender Menge und G{\"u}te ben{\"o}tigen, erscheint inzwischen als Binsenweisheit. Vor diesem Hintergrund hat insbesondere der EU-Gesetzgeber f{\"u}r sich zuletzt ein neues Bet{\"a}tigungsfeld entdeckt, indem er versucht, auf unterschiedlichen Wegen Anreize zum Datenteilen zu schaffen, um Innovation zu kreieren. Hierzu z{\"a}hlt auch eine geradezu wohlt{\"o}nend mit ,,Datenaltruismus'' verschlagwortete Konstellation. Der Beitrag stellt die diesbez{\"u}glichen Regulierungserw{\"a}gungen auf supranationaler Ebene dar und nimmt eine erste Analyse vor.},
language = {de}
}
@article{ShekharReimannMayeretal.2021,
author = {Shekhar, Sumit and Reimann, Max and Mayer, Maximilian and Semmo, Amir and Pasewaldt, Sebastian and D{\"o}llner, J{\"u}rgen and Trapp, Matthias},
title = {Interactive photo editing on smartphones via intrinsic decomposition},
series = {Computer graphics forum : journal of the European Association for Computer Graphics},
volume = {40},
journal = {Computer graphics forum : journal of the European Association for Computer Graphics},
publisher = {Blackwell},
address = {Oxford},
issn = {0167-7055},
doi = {10.1111/cgf.142650},
pages = {497 -- 510},
year = {2021},
abstract = {Intrinsic decomposition refers to the problem of estimating scene characteristics, such as albedo and shading, when one view or multiple views of a scene are provided. The inverse problem setting, where multiple unknowns are solved given a single known pixel-value, is highly under-constrained. When provided with correlating image and depth data, intrinsic scene decomposition can be facilitated using depth-based priors, which nowadays is easy to acquire with high-end smartphones by utilizing their depth sensors. In this work, we present a system for intrinsic decomposition of RGB-D images on smartphones and the algorithmic as well as design choices therein. Unlike state-of-the-art methods that assume only diffuse reflectance, we consider both diffuse and specular pixels. For this purpose, we present a novel specularity extraction algorithm based on a multi-scale intensity decomposition and chroma inpainting. At this, the diffuse component is further decomposed into albedo and shading components. We use an inertial proximal algorithm for non-convex optimization (iPiano) to ensure albedo sparsity. Our GPU-based visual processing is implemented on iOS via the Metal API and enables interactive performance on an iPhone 11 Pro. Further, a qualitative evaluation shows that we are able to obtain high-quality outputs. Furthermore, our proposed approach for specularity removal outperforms state-of-the-art approaches for real-world images, while our albedo and shading layer decomposition is faster than the prior work at a comparable output quality. Manifold applications such as recoloring, retexturing, relighting, appearance editing, and stylization are shown, each using the intrinsic layers obtained with our method and/or the corresponding depth data.},
language = {en}
}
@book{SeitzLinckeReinetal.2021,
author = {Seitz, Klara and Lincke, Jens and Rein, Patrick and Hirschfeld, Robert},
title = {Language and tool support for 3D crochet patterns},
number = {137},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-505-7},
issn = {1613-5652},
doi = {10.25932/publishup-49253},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-492530},
publisher = {Universit{\"a}t Potsdam},
pages = {vii, 94},
year = {2021},
abstract = {Crochet is a popular handcraft all over the world. While other techniques such as knitting or weaving have received technical support over the years through machines, crochet is still a purely manual craft. Not just the act of crochet itself is manual but also the process of creating instructions for new crochet patterns, which is barely supported by domain specific digital solutions. This leads to unstructured and often also ambiguous and erroneous pattern instructions. In this report, we propose a concept to digitally represent crochet patterns. This format incorporates crochet techniques which allows domain specific support for crochet pattern designers during the pattern creation and instruction writing process. As contributions, we present a thorough domain analysis, the concept of a graph structure used as domain specific language to specify crochet patterns and a prototype of a projectional editor using the graph as representation format of patterns and a diagramming system to visualize them in 2D and 3D. By analyzing the domain, we learned about crochet techniques and pain points of designers in their pattern creation workflow. These insights are the basis on which we defined the pattern representation. In order to evaluate our concept, we built a prototype by which the feasibility of the concept is shown and we tested the software with professional crochet designers who approved of the concept.},
language = {en}
}
@article{SchaeferStede2021,
author = {Sch{\"a}fer, Robin and Stede, Manfred},
title = {Argument mining on twitter},
series = {Information technology : it ; Methoden und innovative Anwendungen der Informatik und Informationstechnik ; Organ der Fachbereiche 3 und 4 der GI e.V. und des Fachbereichs 6 der ITG},
volume = {63},
journal = {Information technology : it ; Methoden und innovative Anwendungen der Informatik und Informationstechnik ; Organ der Fachbereiche 3 und 4 der GI e.V. und des Fachbereichs 6 der ITG},
number = {1},
publisher = {De Gruyter},
address = {Berlin},
issn = {1611-2776},
doi = {10.1515/itit-2020-0053},
pages = {45 -- 58},
year = {2021},
abstract = {In the last decade, the field of argument mining has grown notably. However, only relatively few studies have investigated argumentation in social media and specifically on Twitter. Here, we provide the, to our knowledge, first critical in-depth survey of the state of the art in tweet-based argument mining. We discuss approaches to modelling the structure of arguments in the context of tweet corpus annotation, and we review current progress in the task of detecting argument components and their relations in tweets. We also survey the intersection of argument mining and stance detection, before we conclude with an outlook.},
language = {en}
}
@book{SchneiderMaximovaGiese2021,
author = {Schneider, Sven and Maximova, Maria and Giese, Holger},
title = {Probabilistic metric temporal graph logic},
number = {140},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-517-0},
issn = {1613-5652},
doi = {10.25932/publishup-51506},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515066},
publisher = {Universit{\"a}t Potsdam},
pages = {40},
year = {2021},
abstract = {Cyber-physical systems often encompass complex concurrent behavior with timing constraints and probabilistic failures on demand. The analysis whether such systems with probabilistic timed behavior adhere to a given specification is essential. When the states of the system can be represented by graphs, the rule-based formalism of Probabilistic Timed Graph Transformation Systems (PTGTSs) can be used to suitably capture structure dynamics as well as probabilistic and timed behavior of the system. The model checking support for PTGTSs w.r.t. properties specified using Probabilistic Timed Computation Tree Logic (PTCTL) has been already presented. Moreover, for timed graph-based runtime monitoring, Metric Temporal Graph Logic (MTGL) has been developed for stating metric temporal properties on identified subgraphs and their structural changes over time. In this paper, we (a) extend MTGL to the Probabilistic Metric Temporal Graph Logic (PMTGL) by allowing for the specification of probabilistic properties, (b) adapt our MTGL satisfaction checking approach to PTGTSs, and (c) combine the approaches for PTCTL model checking and MTGL satisfaction checking to obtain a Bounded Model Checking (BMC) approach for PMTGL. In our evaluation, we apply an implementation of our BMC approach in AutoGraph to a running example.},
language = {en}
}
@article{SchneiderLambersOrejas2021,
author = {Schneider, Sven and Lambers, Leen and Orejas, Fernando},
title = {A logic-based incremental approach to graph repair featuring delta preservation},
series = {International journal on software tools for technology transfer : STTT},
volume = {23},
journal = {International journal on software tools for technology transfer : STTT},
number = {3},
publisher = {Springer},
address = {Berlin ; Heidelberg},
issn = {1433-2779},
doi = {10.1007/s10009-020-00584-x},
pages = {369 -- 410},
year = {2021},
abstract = {We introduce a logic-based incremental approach to graph repair, generating a sound and complete (upon termination) overview of least-changing graph repairs from which a user may select a graph repair based on non-formalized further requirements. This incremental approach features delta preservation as it allows to restrict the generation of graph repairs to delta-preserving graph repairs, which do not revert the additions and deletions of the most recent consistency-violating graph update. We specify consistency of graphs using the logic of nested graph conditions, which is equivalent to first-order logic on graphs. Technically, the incremental approach encodes if and how the graph under repair satisfies a graph condition using the novel data structure of satisfaction trees, which are adapted incrementally according to the graph updates applied. In addition to the incremental approach, we also present two state-based graph repair algorithms, which restore consistency of a graph independent of the most recent graph update and which generate additional graph repairs using a global perspective on the graph under repair. We evaluate the developed algorithms using our prototypical implementation in the tool AutoGraph and illustrate our incremental approach using a case study from the graph database domain.},
language = {en}
}
@article{SchneiderWenigPapenbrock2021,
author = {Schneider, Johannes and Wenig, Phillip and Papenbrock, Thorsten},
title = {Distributed detection of sequential anomalies in univariate time series},
series = {The VLDB journal : the international journal on very large data bases},
volume = {30},
journal = {The VLDB journal : the international journal on very large data bases},
number = {4},
publisher = {Springer},
address = {Berlin},
issn = {1066-8888},
doi = {10.1007/s00778-021-00657-6},
pages = {579 -- 602},
year = {2021},
abstract = {The automated detection of sequential anomalies in time series is an essential task for many applications, such as the monitoring of technical systems, fraud detection in high-frequency trading, or the early detection of disease symptoms. All these applications require the detection to find all sequential anomalies possibly fast on potentially very large time series. In other words, the detection needs to be effective, efficient and scalable w.r.t. the input size. Series2Graph is an effective solution based on graph embeddings that are robust against re-occurring anomalies and can discover sequential anomalies of arbitrary length and works without training data. Yet, Series2Graph is no t scalable due to its single-threaded approach; it cannot, in particular, process arbitrarily large sequences due to the memory constraints of a single machine. In this paper, we propose our distributed anomaly detection system, short DADS, which is an efficient and scalable adaptation of Series2Graph. Based on the actor programming model, DADS distributes the input time sequence, intermediate state and the computation to all processors of a cluster in a way that minimizes communication costs and synchronization barriers. Our evaluation shows that DADS is orders of magnitude faster than S2G, scales almost linearly with the number of processors in the cluster and can process much larger input sequences due to its scale-out property.},
language = {en}
}
@article{SchindlerMoldenhawerStangeetal.2021,
author = {Schindler, Daniel and Moldenhawer, Ted and Stange, Maike and Lepro, Valentino and Beta, Carsten and Holschneider, Matthias and Huisinga, Wilhelm},
title = {Analysis of protrusion dynamics in amoeboid cell motility by means of regularized contour flows},
series = {PLoS Computational Biology : a new community journal},
volume = {17},
journal = {PLoS Computational Biology : a new community journal},
number = {8},
publisher = {PLoS},
address = {San Fransisco},
issn = {1553-734X},
doi = {10.1371/journal.pcbi.1009268},
pages = {33},
year = {2021},
abstract = {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.
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.},
language = {en}
}
@article{RuedianVladova2021,
author = {R{\"u}dian, Sylvio Leo and Vladova, Gergana},
title = {Kostenfreie Onlinekurse nachhaltig mit personalisiertem Marketing finanzieren},
series = {HMD Praxis der Wirtschaftsinformatik},
volume = {58},
journal = {HMD Praxis der Wirtschaftsinformatik},
number = {3},
publisher = {Springer Vieweg},
address = {Wiesbaden},
issn = {1436-3011},
doi = {10.1365/s40702-021-00720-4},
pages = {507 -- 520},
year = {2021},
abstract = {Selbstbestimmtes Lernen mit Onlinekursen findet zunehmend mehr Akzeptanz in unserer Gesellschaft. Lernende k{\"o}nnen mithilfe von Onlinekursen selbst festlegen, was sie wann lernen und Kurse k{\"o}nnen durch vielf{\"a}ltige Adaptionen an den Lernfortschritt der Nutzer angepasst und individualisiert werden. Auf der einen Seite ist eine große Zielgruppe f{\"u}r diese Lernangebote vorhanden. Auf der anderen Seite sind die Erstellung von Onlinekursen, ihre Bereitstellung, Wartung und Betreuung kostenintensiv, wodurch hochwertige Angebote h{\"a}ufig kostenpflichtig angeboten werden m{\"u}ssen, um als Anbieter zumindest kostenneutral agieren zu k{\"o}nnen. In diesem Beitrag er{\"o}rtern und diskutieren wir ein offenes, nachhaltiges datengetriebenes zweiseitiges Gesch{\"a}ftsmodell zur Verwertung gepr{\"u}fter Onlinekurse und deren kostenfreie Bereitstellung f{\"u}r jeden Lernenden. Kern des Gesch{\"a}ftsmodells ist die Nutzung der dabei entstehenden Verhaltensdaten, die daraus m{\"o}gliche Ableitung von Pers{\"o}nlichkeitsmerkmalen und Interessen und deren Nutzung im kommerziellen Kontext. Dies ist eine bei der Websuche bereits weitl{\"a}ufig akzeptierte Methode, welche nun auf den Lernkontext {\"u}bertragen wird. Welche M{\"o}glichkeiten, Herausforderungen, aber auch Barrieren {\"u}berwunden werden m{\"u}ssen, damit das Gesch{\"a}ftsmodell nachhaltig und ethisch vertretbar funktioniert, werden zwei unabh{\"a}ngige, jedoch synergetisch verbundene Gesch{\"a}ftsmodelle vorgestellt und diskutiert. Zus{\"a}tzlich wurde die Akzeptanz und Erwartung der Zielgruppe f{\"u}r das vorgestellte Gesch{\"a}ftsmodell untersucht, um notwendige Kernressourcen f{\"u}r die Praxis abzuleiten. Die Ergebnisse der Untersuchung zeigen, dass das Gesch{\"a}ftsmodell von den Nutzer*innen grundlegend akzeptiert wird. 10 \% der Befragten w{\"u}rden es bevorzugen, mit virtuellen Assistenten - anstelle mit Tutor*innen zu lernen. Zudem ist der Großteil der Nutzer*innen sich nicht dar{\"u}ber bewusst, dass Pers{\"o}nlichkeitsmerkmale anhand des Nutzerverhaltens abgeleitet werden k{\"o}nnen.},
language = {de}
}
@phdthesis{Rohloff2021,
author = {Rohloff, Tobias},
title = {Learning analytics at scale},
doi = {10.25932/publishup-52623},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-526235},
school = {Universit{\"a}t Potsdam},
pages = {xvii, 138, lxvii},
year = {2021},
abstract = {Digital technologies are paving the way for innovative educational approaches. The learning format of Massive Open Online Courses (MOOCs) provides a highly accessible path to lifelong learning while being more affordable and flexible than face-to-face courses. Thereby, thousands of learners can enroll in courses mostly without admission restrictions, but this also raises challenges. Individual supervision by teachers is barely feasible, and learning persistence and success depend on students' self-regulatory skills. Here, technology provides the means for support. The use of data for decision-making is already transforming many fields, whereas in education, it is still a young research discipline. Learning Analytics (LA) is defined as the measurement, collection, analysis, and reporting of data about learners and their learning contexts with the purpose of understanding and improving learning and learning environments. The vast amount of data that MOOCs produce on the learning behavior and success of thousands of students provides the opportunity to study human learning and develop approaches addressing the demands of learners and teachers. The overall purpose of this dissertation is to investigate the implementation of LA at the scale of MOOCs and to explore how data-driven technology can support learning and teaching in this context. To this end, several research prototypes have been iteratively developed for the HPI MOOC Platform. Hence, they were tested and evaluated in an authentic real-world learning environment. Most of the results can be applied on a conceptual level to other MOOC platforms as well. The research contribution of this thesis thus provides practical insights beyond what is theoretically possible. In total, four system components were developed and extended: (1) The Learning Analytics Architecture: A technical infrastructure to collect, process, and analyze event-driven learning data based on schema-agnostic pipelining in a service-oriented MOOC platform. (2) The Learning Analytics Dashboard for Learners: A tool for data-driven support of self-regulated learning, in particular to enable learners to evaluate and plan their learning activities, progress, and success by themselves. (3) Personalized Learning Objectives: A set of features to better connect learners' success to their personal intentions based on selected learning objectives to offer guidance and align the provided data-driven insights about their learning progress. (4) The Learning Analytics Dashboard for Teachers: A tool supporting teachers with data-driven insights to enable the monitoring of their courses with thousands of learners, identify potential issues, and take informed action. For all aspects examined in this dissertation, related research is presented, development processes and implementation concepts are explained, and evaluations are conducted in case studies. Among other findings, the usage of the learner dashboard in combination with personalized learning objectives demonstrated improved certification rates of 11.62\% to 12.63\%. Furthermore, it was observed that the teacher dashboard is a key tool and an integral part for teaching in MOOCs. In addition to the results and contributions, general limitations of the work are discussed—which altogether provide a solid foundation for practical implications and future research.},
language = {en}
}
@article{QuinzanGoebelWagneretal.2021,
author = {Quinzan, Francesco and G{\"o}bel, Andreas and Wagner, Markus and Friedrich, Tobias},
title = {Evolutionary algorithms and submodular functions},
series = {Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal},
volume = {20},
journal = {Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal},
number = {3},
publisher = {Springer Science + Business Media B.V.},
address = {Dordrecht},
issn = {1572-9796},
doi = {10.1007/s11047-021-09841-7},
pages = {561 -- 575},
year = {2021},
abstract = {A core operator of evolutionary algorithms (EAs) is the mutation. Recently, much attention has been devoted to the study of mutation operators with dynamic and non-uniform mutation rates. Following up on this area of work, we propose a new mutation operator and analyze its performance on the (1 + 1) Evolutionary Algorithm (EA). Our analyses show that this mutation operator competes with pre-existing ones, when used by the (1 + 1) EA on classes of problems for which results on the other mutation operators are available. We show that the (1 + 1) EA using our mutation operator finds a (1/3)-approximation ratio on any non-negative submodular function in polynomial time. We also consider the problem of maximizing a symmetric submodular function under a single matroid constraint and show that the (1 + 1) EA using our operator finds a (1/3)-approximation within polynomial time. This performance matches that of combinatorial local search algorithms specifically designed to solve these problems and outperforms them with constant probability. Finally, we evaluate the performance of the (1 + 1) EA using our operator experimentally by considering two applications: (a) the maximum directed cut problem on real-world graphs of different origins, with up to 6.6 million vertices and 56 million edges and (b) the symmetric mutual information problem using a four month period air pollution data set. In comparison with uniform mutation and a recently proposed dynamic scheme, our operator comes out on top on these instances.},
language = {en}
}
@article{PfitznerSteckhanArnrich2021,
author = {Pfitzner, Bjarne and Steckhan, Nico and Arnrich, Bert},
title = {Federated learning in a medical context},
series = {ACM transactions on internet technology : TOIT / Association for Computing},
volume = {21},
journal = {ACM transactions on internet technology : TOIT / Association for Computing},
number = {2},
publisher = {Association for Computing Machinery},
address = {New York},
issn = {1533-5399},
doi = {10.1145/3412357},
pages = {1 -- 31},
year = {2021},
abstract = {Data privacy is a very important issue. Especially in fields like medicine, it is paramount to abide by the existing privacy regulations to preserve patients' anonymity. However, data is required for research and training machine learning models that could help gain insight into complex correlations or personalised treatments that may otherwise stay undiscovered. Those models generally scale with the amount of data available, but the current situation often prohibits building large databases across sites. So it would be beneficial to be able to combine similar or related data from different sites all over the world while still preserving data privacy. Federated learning has been proposed as a solution for this, because it relies on the sharing of machine learning models, instead of the raw data itself. That means private data never leaves the site or device it was collected on. Federated learning is an emerging research area, and many domains have been identified for the application of those methods. This systematic literature review provides an extensive look at the concept of and research into federated learning and its applicability for confidential healthcare datasets.},
language = {en}
}
@article{PerugiaPaetzelPruesmannAlanenpaeaeetal.2021,
author = {Perugia, Giulia and Paetzel-Pr{\"u}smann, Maike and Alanenp{\"a}{\"a}, Madelene and Castellano, Ginevra},
title = {I can see it in your eyes},
series = {Frontiers in robotics and AI},
volume = {8},
journal = {Frontiers in robotics and AI},
publisher = {Frontiers Media},
address = {Lausanne},
issn = {2296-9144},
doi = {10.3389/frobt.2021.645956},
pages = {18},
year = {2021},
abstract = {Over the past years, extensive research has been dedicated to developing robust platforms and data-driven dialog models to support long-term human-robot interactions. However, little is known about how people's perception of robots and engagement with them develop over time and how these can be accurately assessed through implicit and continuous measurement techniques. In this paper, we explore this by involving participants in three interaction sessions with multiple days of zero exposure in between. Each session consists of a joint task with a robot as well as two short social chats with it before and after the task. We measure participants' gaze patterns with a wearable eye-tracker and gauge their perception of the robot and engagement with it and the joint task using questionnaires. Results disclose that aversion of gaze in a social chat is an indicator of a robot's uncanniness and that the more people gaze at the robot in a joint task, the worse they perform. In contrast with most HRI literature, our results show that gaze toward an object of shared attention, rather than gaze toward a robotic partner, is the most meaningful predictor of engagement in a joint task. Furthermore, the analyses of gaze patterns in repeated interactions disclose that people's mutual gaze in a social chat develops congruently with their perceptions of the robot over time. These are key findings for the HRI community as they entail that gaze behavior can be used as an implicit measure of people's perception of robots in a social chat and of their engagement and task performance in a joint task.},
language = {en}
}
@article{Perscheid2021,
author = {Perscheid, Cindy},
title = {Integrative biomarker detection on high-dimensional gene expression data sets},
series = {Briefings in bioinformatics},
volume = {22},
journal = {Briefings in bioinformatics},
number = {3},
publisher = {Oxford Univ. Press},
address = {Oxford},
issn = {1467-5463},
doi = {10.1093/bib/bbaa151},
pages = {18},
year = {2021},
abstract = {Gene expression data provide the expression levels of tens of thousands of genes from several hundred samples. These data are analyzed to detect biomarkers that can be of prognostic or diagnostic use. Traditionally, biomarker detection for gene expression data is the task of gene selection. The vast number of genes is reduced to a few relevant ones that achieve the best performance for the respective use case. Traditional approaches select genes based on their statistical significance in the data set. This results in issues of robustness, redundancy and true biological relevance of the selected genes. Integrative analyses typically address these shortcomings by integrating multiple data artifacts from the same objects, e.g. gene expression and methylation data. When only gene expression data are available, integrative analyses instead use curated information on biological processes from public knowledge bases. With knowledge bases providing an ever-increasing amount of curated biological knowledge, such prior knowledge approaches become more powerful. This paper provides a thorough overview on the status quo of biomarker detection on gene expression data with prior biological knowledge. We discuss current shortcomings of traditional approaches, review recent external knowledge bases, provide a classification and qualitative comparison of existing prior knowledge approaches and discuss open challenges for this kind of gene selection.},
language = {en}
}
@article{Perscheid2021,
author = {Perscheid, Cindy},
title = {Comprior},
series = {BMC Bioinformatics},
volume = {22},
journal = {BMC Bioinformatics},
publisher = {Springer Nature},
address = {London},
issn = {1471-2105},
doi = {10.1186/s12859-021-04308-z},
pages = {1 -- 15},
year = {2021},
abstract = {Background Reproducible benchmarking is important for assessing the effectiveness of novel feature selection approaches applied on gene expression data, especially for prior knowledge approaches that incorporate biological information from online knowledge bases. However, no full-fledged benchmarking system exists that is extensible, provides built-in feature selection approaches, and a comprehensive result assessment encompassing classification performance, robustness, and biological relevance. Moreover, the particular needs of prior knowledge feature selection approaches, i.e. uniform access to knowledge bases, are not addressed. As a consequence, prior knowledge approaches are not evaluated amongst each other, leaving open questions regarding their effectiveness. Results We present the Comprior benchmark tool, which facilitates the rapid development and effortless benchmarking of feature selection approaches, with a special focus on prior knowledge approaches. Comprior is extensible by custom approaches, offers built-in standard feature selection approaches, enables uniform access to multiple knowledge bases, and provides a customizable evaluation infrastructure to compare multiple feature selection approaches regarding their classification performance, robustness, runtime, and biological relevance. Conclusion Comprior allows reproducible benchmarking especially of prior knowledge approaches, which facilitates their applicability and for the first time enables a comprehensive assessment of their effectiveness},
language = {en}
}
@article{PawassarTiberius2021,
author = {Pawassar, Christian Matthias and Tiberius, Victor},
title = {Virtual reality in health care},
series = {JMIR Serious Games},
volume = {9},
journal = {JMIR Serious Games},
edition = {4},
publisher = {JMIR Publications},
address = {Toronto, Kanada},
issn = {2291-9279},
doi = {10.2196/32721},
pages = {1 -- 19},
year = {2021},
abstract = {Background: Research into the application of virtual reality technology in the health care sector has rapidly increased, resulting in a large body of research that is difficult to keep up with. Objective: We will provide an overview of the annual publication numbers in this field and the most productive and influential countries, journals, and authors, as well as the most used, most co-occurring, and most recent keywords. Methods: Based on a data set of 356 publications and 20,363 citations derived from Web of Science, we conducted a bibliometric analysis using BibExcel, HistCite, and VOSviewer. Results: The strongest growth in publications occurred in 2020, accounting for 29.49\% of all publications so far. The most productive countries are the United States, the United Kingdom, and Spain; the most influential countries are the United States, Canada, and the United Kingdom. The most productive journals are the Journal of Medical Internet Research (JMIR), JMIR Serious Games, and the Games for Health Journal; the most influential journals are Patient Education and Counselling, Medical Education, and Quality of Life Research. The most productive authors are Riva, del Piccolo, and Schwebel; the most influential authors are Finset, del Piccolo, and Eide. The most frequently occurring keywords other than "virtual" and "reality" are "training," "trial," and "patients." The most relevant research themes are communication, education, and novel treatments; the most recent research trends are fitness and exergames. Conclusions: The analysis shows that the field has left its infant state and its specialization is advancing, with a clear focus on patient usability.},
language = {en}
}
@phdthesis{Pape2021,
author = {Pape, Tobias},
title = {Efficient compound values in virtual machines},
doi = {10.25932/publishup-49913},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-499134},
school = {Universit{\"a}t Potsdam},
pages = {xxix, 242},
year = {2021},
abstract = {Compound values are not universally supported in virtual machine (VM)-based programming systems and languages. However, providing data structures with value characteristics can be beneficial. On one hand, programming systems and languages can adequately represent physical quantities with compound values and avoid inconsistencies, for example, in representation of large numbers. On the other hand, just-in-time (JIT) compilers, which are often found in VMs, can rely on the fact that compound values are immutable, which is an important property in optimizing programs. Considering this, compound values have an optimization potential that can be put to use by implementing them in VMs in a way that is efficient in memory usage and execution time. Yet, optimized compound values in VMs face certain challenges: to maintain consistency, it should not be observable by the program whether compound values are represented in an optimized way by a VM; an optimization should take into account, that the usage of compound values can exhibit certain patterns at run-time; and that necessary value-incompatible properties due to implementation restrictions should be reduced. We propose a technique to detect and compress common patterns of compound value usage at run-time to improve memory usage and execution speed. Our approach identifies patterns of frequent compound value references and introduces abbreviated forms for them. Thus, it is possible to store multiple inter-referenced compound values in an inlined memory representation, reducing the overhead of metadata and object references. We extend our approach by a notion of limited mutability, using cells that act as barriers for our approach and provide a location for shared, mutable access with the possibility of type specialization. We devise an extension to our approach that allows us to express automatic unboxing of boxed primitive data types in terms of our initial technique. We show that our approach is versatile enough to express another optimization technique that relies on values, such as Booleans, that are unique throughout a programming system. Furthermore, we demonstrate how to re-use learned usage patterns and optimizations across program runs, thus reducing the performance impact of pattern recognition. We show in a best-case prototype that the implementation of our approach is feasible and can also be applied to general purpose programming systems, namely implementations of the Racket language and Squeak/Smalltalk. In several micro-benchmarks, we found that our approach can effectively reduce memory consumption and improve execution speed.},
language = {en}
}
@article{PaetzelPruesmannPerugiaCastellano2021,
author = {Paetzel-Pr{\"u}smann, Maike and Perugia, Giulia and Castellano, Ginevra},
title = {The influence of robot personality on the development of uncanny feelings},
series = {Computers in human behavior},
volume = {120},
journal = {Computers in human behavior},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0747-5632},
doi = {10.1016/j.chb.2021.106756},
pages = {17},
year = {2021},
abstract = {Empirical investigations on the uncanny valley have almost solely focused on the analysis of people?s noninteractive perception of a robot at first sight. Recent studies suggest, however, that these uncanny first impressions may be significantly altered over an interaction. What is yet to discover is whether certain interaction patterns can lead to a faster decline in uncanny feelings. In this paper, we present a study in which participants with limited expertise in Computer Science played a collaborative geography game with a Furhat robot. During the game, Furhat displayed one of two personalities, which corresponded to two different interaction strategies. The robot was either optimistic and encouraging, or impatient and provocative. We performed the study in a science museum and recruited participants among the visitors. Our findings suggest that a robot that is rated high on agreeableness, emotional stability, and conscientiousness can indeed weaken uncanny feelings. This study has important implications for human-robot interaction design as it further highlights that a first impression, merely based on a robot?s appearance, is not indicative of the affinity people might develop towards it throughout an interaction. We thus argue that future work should emphasize investigations on exact interaction patterns that can help to overcome uncanny feelings.},
language = {en}
}
@article{OosthoekDoerr2021,
author = {Oosthoek, Kris and D{\"o}rr, Christian},
title = {Cyber security threats to bitcoin exchanges},
series = {IEEE transactions on network and service management : a publication of the IEEE},
volume = {18},
journal = {IEEE transactions on network and service management : a publication of the IEEE},
number = {2},
publisher = {IEEE},
address = {New York},
issn = {1932-4537},
doi = {10.1109/TNSM.2020.3046145},
pages = {1616 -- 1628},
year = {2021},
abstract = {Bitcoin is gaining traction as an alternative store of value. Its market capitalization transcends all other cryptocurrencies in the market. But its high monetary value also makes it an attractive target to cyber criminal actors. Hacking campaigns usually target an ecosystem's weakest points. In Bitcoin, the exchange platforms are one of them. Each exchange breach is a threat not only to direct victims, but to the credibility of Bitcoin's entire ecosystem. Based on an extensive analysis of 36 breaches of Bitcoin exchanges, we show the attack patterns used to exploit Bitcoin exchange platforms using an industry standard for reporting intelligence on cyber security breaches. Based on this we are able to provide an overview of the most common attack vectors, showing that all except three hacks were possible due to relatively lax security. We show that while the security regimen of Bitcoin exchanges is subpar compared to other financial service providers, the use of stolen credentials, which does not require any hacking, is decreasing. We also show that the amount of BTC taken during a breach is decreasing, as well as the exchanges that terminate after being breached. Furthermore we show that overall security posture has improved, but still has major flaws. To discover adversarial methods post-breach, we have analyzed two cases of BTC laundering. Through this analysis we provide insight into how exchange platforms with lax cyber security even further increase the intermediary risk introduced by them into the Bitcoin ecosystem.},
language = {en}
}
@article{OmranianAngeleskaNikoloski2021,
author = {Omranian, Sara and Angeleska, Angela and Nikoloski, Zoran},
title = {PC2P},
series = {Bioinformatics},
volume = {37},
journal = {Bioinformatics},
number = {1},
publisher = {Oxford Univ. Press},
address = {Oxford},
issn = {1367-4811},
doi = {10.1093/bioinformatics/btaa1089},
pages = {73 -- 81},
year = {2021},
abstract = {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.},
language = {en}
}
@article{NavarroOrejasPinoetal.2021,
author = {Navarro, Marisa and Orejas, Fernando and Pino, Elvira and Lambers, Leen},
title = {A navigational logic for reasoning about graph properties},
series = {Journal of logical and algebraic methods in programming},
volume = {118},
journal = {Journal of logical and algebraic methods in programming},
publisher = {Elsevier Science},
address = {Amsterdam [u.a.]},
issn = {2352-2208},
doi = {10.1016/j.jlamp.2020.100616},
pages = {33},
year = {2021},
abstract = {Graphs play an important role in many areas of Computer Science. In particular, our work is motivated by model-driven software development and by graph databases. For this reason, it is very important to have the means to express and to reason about the properties that a given graph may satisfy. With this aim, in this paper we present a visual logic that allows us to describe graph properties, including navigational properties, i.e., properties about the paths in a graph. The logic is equipped with a deductive tableau method that we have proved to be sound and complete.},
language = {en}
}
@book{MeinelDoellnerWeskeetal.2021,
author = {Meinel, Christoph and D{\"o}llner, J{\"u}rgen Roland Friedrich and Weske, Mathias and Polze, Andreas and Hirschfeld, Robert and Naumann, Felix and Giese, Holger and Baudisch, Patrick and Friedrich, Tobias and B{\"o}ttinger, Erwin and Lippert, Christoph and D{\"o}rr, Christian and Lehmann, Anja and Renard, Bernhard and Rabl, Tilmann and Uebernickel, Falk and Arnrich, Bert and H{\"o}lzle, Katharina},
title = {Proceedings of the HPI Research School on Service-oriented Systems Engineering 2020 Fall Retreat},
number = {138},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-513-2},
issn = {1613-5652},
doi = {10.25932/publishup-50413},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-504132},
publisher = {Universit{\"a}t Potsdam},
pages = {vi, 144},
year = {2021},
abstract = {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.},
language = {en}
}
@book{MaximovaSchneiderGiese2021,
author = {Maximova, Maria and Schneider, Sven and Giese, Holger},
title = {Interval probabilistic timed graph transformation systems},
number = {134},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-502-6},
issn = {1613-5652},
doi = {10.25932/publishup-51289},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-512895},
publisher = {Universit{\"a}t Potsdam},
pages = {58},
year = {2021},
abstract = {The formal modeling and analysis is of crucial importance for software development processes following the model based approach. We present the formalism of Interval Probabilistic Timed Graph Transformation Systems (IPTGTSs) as a high-level modeling language. This language supports structure dynamics (based on graph transformation), timed behavior (based on clocks, guards, resets, and invariants as in Timed Automata (TA)), and interval probabilistic behavior (based on Discrete Interval Probability Distributions). That is, for the probabilistic behavior, the modeler using IPTGTSs does not need to provide precise probabilities, which are often impossible to obtain, but rather provides a probability range instead from which a precise probability is chosen nondeterministically. In fact, this feature on capturing probabilistic behavior distinguishes IPTGTSs from Probabilistic Timed Graph Transformation Systems (PTGTSs) presented earlier. Following earlier work on Interval Probabilistic Timed Automata (IPTA) and PTGTSs, we also provide an analysis tool chain for IPTGTSs based on inter-formalism transformations. In particular, we provide in our tool AutoGraph a translation of IPTGTSs to IPTA and rely on a mapping of IPTA to Probabilistic Timed Automata (PTA) to allow for the usage of the Prism model checker. The tool Prism can then be used to analyze the resulting PTA w.r.t. probabilistic real-time queries asking for worst-case and best-case probabilities to reach a certain set of target states in a given amount of time.},
language = {en}
}
@phdthesis{Makowski2021,
author = {Makowski, Silvia},
title = {Discriminative Models for Biometric Identification using Micro- and Macro-Movements of the Eyes},
school = {Universit{\"a}t Potsdam},
pages = {xi, 91},
year = {2021},
abstract = {Human visual perception is an active process. Eye movements either alternate between fixations and saccades or follow a smooth pursuit movement in case of moving targets. Besides these macroscopic gaze patterns, the eyes perform involuntary micro-movements during fixations which are commonly categorized into micro-saccades, drift and tremor. Eye movements are frequently studied in cognitive psychology, because they reflect a complex interplay of perception, attention and oculomotor control. A common insight of psychological research is that macro-movements are highly individual. Inspired by this finding, there has been a considerable amount of prior research on oculomotoric biometric identification. However, the accuracy of known approaches is too low and the time needed for identification is too long for any practical application. This thesis explores discriminative models for the task of biometric identification. Discriminative models optimize a quality measure of the predictions and are usually superior to generative approaches in discriminative tasks. However, using discriminative models requires to select a suitable form of data representation for sequential eye gaze data; i.e., by engineering features or constructing a sequence kernel and the performance of the classification model strongly depends on the data representation. We study two fundamentally different ways of representing eye gaze within a discriminative framework. In the first part of this thesis, we explore the integration of data and psychological background knowledge in the form of generative models to construct representations. To this end, we first develop generative statistical models of gaze behavior during reading and scene viewing that account for viewer-specific distributional properties of gaze patterns. In a second step, we develop a discriminative identification model by deriving Fisher kernel functions from these and several baseline models. We find that an SVM with Fisher kernel is able to reliably identify users based on their eye gaze during reading and scene viewing. However, since the generative models are constrained to use low-frequency macro-movements, they discard a significant amount of information contained in the raw eye tracking signal at a high cost: identification requires about one minute of input recording, which makes it inapplicable for real world biometric systems. In the second part of this thesis, we study a purely data-driven modeling approach. Here, we aim at automatically discovering the individual pattern hidden in the raw eye tracking signal. To this end, we develop a deep convolutional neural network DeepEyedentification that processes yaw and pitch gaze velocities and learns a representation end-to-end. Compared to prior work, this model increases the identification accuracy by one order of magnitude and the time to identification decreases to only seconds. The DeepEyedentificationLive model further improves upon the identification performance by processing binocular input and it also detects presentation-attacks. We find that by learning a representation, the performance of oculomotoric identification and presentation-attack detection can be driven close to practical relevance for biometric applications. Eye tracking devices with high sampling frequency and precision are expensive and the applicability of eye movement as a biometric feature heavily depends on cost of recording devices. In the last part of this thesis, we therefore study the requirements on data quality by evaluating the performance of the DeepEyedentificationLive network under reduced spatial and temporal resolution. We find that the method still attains a high identification accuracy at a temporal resolution of only 250 Hz and a precision of 0.03 degrees. Reducing both does not have an additive deteriorating effect.},
language = {en}
}
@article{MagkosKupschBruno2021,
author = {Magkos, Sotirios and Kupsch, Andreas and Bruno, Giovanni},
title = {Suppression of cone-beam artefacts with Direct Iterative Reconstruction Computed Tomography Trajectories (DIRECTT)},
series = {Journal of imaging : open access journal},
volume = {7},
journal = {Journal of imaging : open access journal},
number = {8},
publisher = {MDPI},
address = {Basel},
issn = {2313-433X},
doi = {10.3390/jimaging7080147},
pages = {9},
year = {2021},
abstract = {The reconstruction of cone-beam computed tomography data using filtered back-projection algorithms unavoidably results in severe artefacts. We describe how the Direct Iterative Reconstruction of Computed Tomography Trajectories (DIRECTT) algorithm can be combined with a model of the artefacts for the reconstruction of such data. The implementation of DIRECTT results in reconstructed volumes of superior quality compared to the conventional algorithms.},
language = {en}
}
@article{LosterKoumarelasNaumann2021,
author = {Loster, Michael and Koumarelas, Ioannis and Naumann, Felix},
title = {Knowledge transfer for entity resolution with siamese neural networks},
series = {ACM journal of data and information quality},
volume = {13},
journal = {ACM journal of data and information quality},
number = {1},
publisher = {Association for Computing Machinery},
address = {New York},
issn = {1936-1955},
doi = {10.1145/3410157},
pages = {25},
year = {2021},
abstract = {The integration of multiple data sources is a common problem in a large variety of applications. Traditionally, handcrafted similarity measures are used to discover, merge, and integrate multiple representations of the same entity-duplicates-into a large homogeneous collection of data. Often, these similarity measures do not cope well with the heterogeneity of the underlying dataset. In addition, domain experts are needed to manually design and configure such measures, which is both time-consuming and requires extensive domain expertise.
We propose a deep Siamese neural network, capable of learning a similarity measure that is tailored to the characteristics of a particular dataset. With the properties of deep learning methods, we are able to eliminate the manual feature engineering process and thus considerably reduce the effort required for model construction. In addition, we show that it is possible to transfer knowledge acquired during the deduplication of one dataset to another, and thus significantly reduce the amount of data required to train a similarity measure. We evaluated our method on multiple datasets and compare our approach to state-of-the-art deduplication methods. Our approach outperforms competitors by up to +26 percent F-measure, depending on task and dataset. In addition, we show that knowledge transfer is not only feasible, but in our experiments led to an improvement in F-measure of up to +4.7 percent.},
language = {en}
}
@article{LambersOrejas2021,
author = {Lambers, Leen and Orejas, Fernando},
title = {Transformation rules with nested application conditions},
series = {Theoretical computer science},
volume = {884},
journal = {Theoretical computer science},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0304-3975},
doi = {10.1016/j.tcs.2021.07.023},
pages = {44 -- 67},
year = {2021},
abstract = {Recently, initial conflicts were introduced in the framework of M-adhesive categories as an important optimization of critical pairs. In particular, they represent a proper subset such that each conflict is represented in a minimal context by a unique initial one. The theory of critical pairs has been extended in the framework of M-adhesive categories to rules with nested application conditions (ACs), restricting the applicability of a rule and generalizing the well-known negative application conditions. A notion of initial conflicts for rules with ACs does not exist yet. In this paper, on the one hand, we extend the theory of initial conflicts in the framework of M-adhesive categories to transformation rules with ACs. They represent a proper subset again of critical pairs for rules with ACs, and represent each conflict in a minimal context uniquely. They are moreover symbolic because we can show that in general no finite and complete set of conflicts for rules with ACs exists. On the other hand, we show that critical pairs are minimally M-complete, whereas initial conflicts are minimally complete. Finally, we introduce important special cases of rules with ACs for which we can obtain finite, minimally (M-)complete sets of conflicts.},
language = {en}
}
@article{LadleifWeske2021,
author = {Ladleif, Jan and Weske, Mathias},
title = {Which event happened first?},
series = {Frontiers in blockchain},
volume = {4},
journal = {Frontiers in blockchain},
publisher = {Frontiers in Blockchain},
address = {Lausanne, Schweiz},
issn = {2624-7852},
doi = {10.3389/fbloc.2021.758169},
pages = {1 -- 16},
year = {2021},
abstract = {First come, first served: Critical choices between alternative actions are often made based on events external to an organization, and reacting promptly to their occurrence can be a major advantage over the competition. In Business Process Management (BPM), such deferred choices can be expressed in process models, and they are an important aspect of process engines. Blockchain-based process execution approaches are no exception to this, but are severely limited by the inherent properties of the platform: The isolated environment prevents direct access to external entities and data, and the non-continual runtime based entirely on atomic transactions impedes the monitoring and detection of events. In this paper we provide an in-depth examination of the semantics of deferred choice, and transfer them to environments such as the blockchain. We introduce and compare several oracle architectures able to satisfy certain requirements, and show that they can be implemented using state-of-the-art blockchain technology.},
language = {en}
}
@misc{LadleifWeske2021,
author = {Ladleif, Jan and Weske, Mathias},
title = {Which Event Happened First? Deferred Choice on Blockchain Using Oracles},
series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Reihe der Digital Engineering Fakult{\"a}t},
volume = {4},
journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Reihe der Digital Engineering Fakult{\"a}t},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
doi = {10.25932/publishup-55068},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-550681},
pages = {1 -- 16},
year = {2021},
abstract = {First come, first served: Critical choices between alternative actions are often made based on events external to an organization, and reacting promptly to their occurrence can be a major advantage over the competition. In Business Process Management (BPM), such deferred choices can be expressed in process models, and they are an important aspect of process engines. Blockchain-based process execution approaches are no exception to this, but are severely limited by the inherent properties of the platform: The isolated environment prevents direct access to external entities and data, and the non-continual runtime based entirely on atomic transactions impedes the monitoring and detection of events. In this paper we provide an in-depth examination of the semantics of deferred choice, and transfer them to environments such as the blockchain. We introduce and compare several oracle architectures able to satisfy certain requirements, and show that they can be implemented using state-of-the-art blockchain technology.},
language = {en}
}
@article{KuehlMuenzer2021,
author = {K{\"u}hl, Tim and M{\"u}nzer, Stefan},
title = {Learning about a serious disease},
series = {Journal of computer assisted learning : JCAL},
volume = {37},
journal = {Journal of computer assisted learning : JCAL},
number = {5},
publisher = {Wiley-Blackwell},
address = {Oxford [u.a.]},
issn = {0266-4909},
doi = {10.1111/jcal.12571},
pages = {1312 -- 1323},
year = {2021},
abstract = {According to the personalization principle, addressing learners by means of a personalized compared to a nonpersonalized message can foster learning. Interestingly, though, a recent study found that the personalization principle can invert for aversive contents. The present study investigated whether the negative effect of a personalized message for an aversive content can be compensated when learners are in a happy mood. It was hypothesized that the negative effect of a personalized compared to a nonpersonalized message would only be observable for participants in a sad mood, while for participants in a happy mood a personalized message should be beneficial. A 2 x 2 between-subject design with mood (happy vs. sad) and personalization (personalized vs. nonpersonalized message) was used (N = 125 University students). Mood was experimentally varied prior to learning. Learning outcomes were measured by a retention and a transfer test. Results were essentially in line with the assumption: For participants in the sad mood condition, a negative effect of a personalized message was observable for retention and transfer. For participants in the happy mood condition, a positive effect of personalized message was observable for retention, but no effect for transfer. Note that the manipulation check measure for the mood induction procedure did not detect differences between conditions; this may be due to a shortcoming of the used measure (as indicated by an additional evaluation study). The study emphasizes the importance to consider the inherent emotional content of a topic, such as its aversive nature, since the emotional content of a topic can be a boundary condition for design principles in multimedia learning. The study also highlights the complex interplay of externally induced and inherently arising emotions.},
language = {en}
}
@article{KoerppenUllrichBertheau2021,
author = {K{\"o}rppen, Tim and Ullrich, Andr{\´e} and Bertheau, Clementine},
title = {Durchblick statt Bauchgef{\"u}hl - Transformation zur Data-Driven Organization},
series = {Wirtschaftsinformatik \& Management},
volume = {13},
journal = {Wirtschaftsinformatik \& Management},
number = {6},
publisher = {Springer Gabler},
address = {Wiesbaden},
issn = {1867-5905},
doi = {10.1365/s35764-021-00370-7},
pages = {452 -- 459},
year = {2021},
abstract = {Um in der digitalisierten Wirtschaft mitzuspielen, m{\"u}ssen Unternehmen, Markt und insbesondere Kunden detailliert verstanden werden. Neben den „Big Playern" aus dem Silicon Valley sieht der deutsche Mittelstand, der zu großen Teilen noch auf gewachsenen IT-Infrastrukturen und Prozessen agiert, oft alt aus. Um in den n{\"a}chsten Jahren nicht g{\"a}nzlich abgeh{\"a}ngt zu werden, ist ein Umbruch notwendig. Sowohl Leistungserstellungsprozesse als auch Leistungsangebot m{\"u}ssen transparent und datenbasiert ausgerichtet werden. Nur so k{\"o}nnen Gesch{\"a}ftsvorf{\"a}lle, das Marktgeschehen sowie Handeln der Akteure integrativ bewertet und fundierte Entscheidungen getroffen werden. In diesem Beitrag wird das Konzept der Data-Driven Organization vorgestellt und aufgezeigt, wie Unternehmen den eigenen Analyticsreifegrad ermitteln und in einem iterativen Transformationsprozess steigern k{\"o}nnen.},
language = {de}
}
@article{KreowskyStabernack2021,
author = {Kreowsky, Philipp and Stabernack, Christian Benno},
title = {A full-featured FPGA-based pipelined architecture for SIFT extraction},
series = {IEEE access : practical research, open solutions / Institute of Electrical and Electronics Engineers},
volume = {9},
journal = {IEEE access : practical research, open solutions / Institute of Electrical and Electronics Engineers},
publisher = {Inst. of Electr. and Electronics Engineers},
address = {New York, NY},
issn = {2169-3536},
doi = {10.1109/ACCESS.2021.3104387},
pages = {128564 -- 128573},
year = {2021},
abstract = {Image feature detection is a key task in computer vision. Scale Invariant Feature Transform (SIFT) is a prevalent and well known algorithm for robust feature detection. However, it is computationally demanding and software implementations are not applicable for real-time performance. In this paper, a versatile and pipelined hardware implementation is proposed, that is capable of computing keypoints and rotation invariant descriptors on-chip. All computations are performed in single precision floating-point format which makes it possible to implement the original algorithm with little alteration. Various rotation resolutions and filter kernel sizes are supported for images of any resolution up to ultra-high definition. For full high definition images, 84 fps can be processed. Ultra high definition images can be processed at 21 fps.},
language = {en}
}
@inproceedings{KrauseBaumann2021,
author = {Krause, Hannes-Vincent and Baumann, Annika},
title = {The devil in disguise},
series = {ICIS 2021: user behaviors, engagement, and consequences},
booktitle = {ICIS 2021: user behaviors, engagement, and consequences},
publisher = {AIS Electronic Library (AISeL)},
address = {[Erscheinungsort nicht ermittelbar]},
year = {2021},
abstract = {Envy constitutes a serious issue on Social Networking Sites (SNSs), as this painful emotion can severely diminish individuals' well-being. With prior research mainly focusing on the affective consequences of envy in the SNS context, its behavioral consequences remain puzzling. While negative interactions among SNS users are an alarming issue, it remains unclear to which extent the harmful emotion of malicious envy contributes to these toxic dynamics. This study constitutes a first step in understanding malicious envy's causal impact on negative interactions within the SNS sphere. Within an online experiment, we experimentally induce malicious envy and measure its immediate impact on users' negative behavior towards other users. Our findings show that malicious envy seems to be an essential factor fueling negativity among SNS users and further illustrate that this effect is especially pronounced when users are provided an objective factor to mask their envy and justify their norm-violating negative behavior.},
language = {en}
}
@inproceedings{KrasnovagrosseDetersGladkaya2021,
author = {Krasnova, Hanna and große Deters, Fenne and Gladkaya, Margarita},
title = {Examining social media as a driver of perfectionism},
series = {PACIS 2021 proceedings},
booktitle = {PACIS 2021 proceedings},
publisher = {AIS Electronic Library (AISeL)},
address = {[Erscheinungsort nicht ermittelbar]},
isbn = {978-1-7336325-7-7},
year = {2021},
abstract = {Perfectionism is a personality disposition characterized by setting extremely high performance-standards coupled with critical self-evaluations. Often conceived as positive, perfectionism can yield not only beneficial but also deleterious outcomes ranging from anxiety to burnout. In this proposal, we set out to investigate the role of the technology and, particularly, social media in individuals' strivings for perfection. We lay down theoretical bases for the possibility that social media plays a role in the development of perfectionism. To empirically test the hypothesized relationship, we propose a comprehensive study design based on the experience sampling method. Lastly, we provide an overview of the planned analysis and future steps.},
language = {en}
}
@article{KossmannPapenbrockNaumann2021,
author = {Koßmann, Jan and Papenbrock, Thorsten and Naumann, Felix},
title = {Data dependencies for query optimization},
series = {The VLDB journal : the international journal on very large data bases / publ. on behalf of the VLDB Endowment},
volume = {31},
journal = {The VLDB journal : the international journal on very large data bases / publ. on behalf of the VLDB Endowment},
number = {1},
publisher = {Springer},
address = {Berlin ; Heidelberg ; New York},
issn = {1066-8888},
doi = {10.1007/s00778-021-00676-3},
pages = {1 -- 22},
year = {2021},
abstract = {Effective query optimization is a core feature of any database management system. While most query optimization techniques make use of simple metadata, such as cardinalities and other basic statistics, other optimization techniques are based on more advanced metadata including data dependencies, such as functional, uniqueness, order, or inclusion dependencies. This survey provides an overview, intuitive descriptions, and classifications of query optimization and execution strategies that are enabled by data dependencies. We consider the most popular types of data dependencies and focus on optimization strategies that target the optimization of relational database queries. The survey supports database vendors to identify optimization opportunities as well as DBMS researchers to find related work and open research questions.},
language = {en}
}
@article{Kleemann2021,
author = {Kleemann, Steven},
title = {Cyber warfare and the "humanization" of international humanitarian law},
series = {International journal of cyber warfare and terrorism},
volume = {11},
journal = {International journal of cyber warfare and terrorism},
number = {2},
publisher = {IGI Global},
address = {Hershey},
isbn = {978-1-7998-6177-5},
issn = {1947-3435},
doi = {10.4018/IJCWT.2021040101},
pages = {1 -- 11},
year = {2021},
abstract = {Cyber warfare is a timely and relevant issue and one of the most controversial in international humanitarian law (IHL). The aim of IHL is to set rules and limits in terms of means and methods of warfare. In this context, a key question arises: Has digital warfare rules or limits, and if so, how are these applicable? Traditional principles, developed over a long period, are facing a new dimension of challenges due to the rise of cyber warfare. This paper argues that to overcome this new issue, it is critical that new humanity-oriented approaches is developed with regard to cyber warfare. The challenge is to establish a legal regime for cyber-attacks, successfully addressing human rights norms and standards. While clarifying this from a legal perspective, the authors can redesign the sensitive equilibrium between humanity and military necessity, weighing the humanitarian aims of IHL and the protection of civilians-in combination with international human rights law and other relevant legal regimes-in a different manner than before.},
language = {en}
}
@inproceedings{JacqminOezdemirFellKurbanetal.2021,
author = {Jacqmin, Julien and {\"O}zdemir, Paker Doğu and Fell Kurban, Caroline and Tun{\c{c}} Pekkan, Zelha and Koskinen, Johanna and Suonp{\"a}{\"a}, Maija and Seng, Cheyvuth and Carlon, May Kristine Jonson and Gayed, John Maurice and Cross, Jeffrey S. and Langseth, Inger and Jacobsen, Dan Yngve and Haugsbakken, Halvdan and Bethge, Joseph and Serth, Sebastian and Staubitz, Thomas and Wuttke, Tobias and Nordemann, Oliver and Das, Partha-Pratim and Meinel, Christoph and Ponce, Eva and Srinath, Sindhu and Allegue, Laura and Perach, Shai and Alexandron, Giora and Corti, Paola and Baudo, Valeria and Turr{\´o}, Carlos and Moura Santos, Ana and Nilsson, Charlotta and Maldonado-Mahauad, Jorge and Valdiviezo, Javier and Carvallo, Juan Pablo and Samaniego-Erazo, Nicolay and Poce, Antonella and Re, Maria Rosaria and Valente, Mara and Karp Gershon, Sa'ar and Ruip{\´e}rez-Valiente, Jos{\´e} A. and Despujol, Ignacio and Busquets, Jaime and Kerr, John and Lorenz, Anja and Sch{\"o}n, Sandra and Ebner, Martin and Wittke, Andreas and Beirne, Elaine and Nic Giolla Mhich{\´i}l, Mair{\´e}ad and Brown, Mark and Mac Lochlainn, Conch{\´u}r and Topali, Paraskevi and Chounta, Irene-Angelica and Ortega-Arranz, Alejandro and Villagr{\´a}-Sobrino, Sara L. and Mart{\´i}nez-Mon{\´e}s, Alejandra and Blackwell, Virginia Katherine and Wiltrout, Mary Ellen and Rami Gaddem, Mohamed and Hern{\´a}ndez Reyes, C{\´e}sar Augusto and Nagahama, Toru and Buchem, Ilona and Okatan, Ebru and Khalil, Mohammad and Casiraghi, Daniela and Sancassani, Susanna and Brambilla, Federica and Mihaescu, Vlad and Andone, Diana and Vasiu, Radu and Şahin, Muhittin and Egloffstein, Marc and Bothe, Max and Rohloff, Tobias and Schenk, Nathanael and Schwerer, Florian and Ifenthaler, Dirk and Hense, Julia and Bernd, Mike},
title = {EMOOCs 2021},
editor = {Meinel, Christoph and Staubitz, Thomas and Schweiger, Stefanie and Friedl, Christian and Kiers, Janine and Ebner, Martin and Lorenz, Anja and Ubachs, George and Mongenet, Catherine and Ruip{\´e}rez-Valiente, Jos{\´e} A. and Cortes Mendez, Manoel},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-512-5},
doi = {10.25932/publishup-51030},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-510300},
pages = {vii, 295},
year = {2021},
abstract = {From June 22 to June 24, 2021, Hasso Plattner Institute, Potsdam, hosted the seventh European MOOC Stakeholder Summit (EMOOCs 2021) together with the eighth ACM Learning@Scale Conference. Due to the COVID-19 situation, the conference was held fully online. The boost in digital education worldwide as a result of the pandemic was also one of the main topics of this year's EMOOCs. All institutions of learning have been forced to transform and redesign their educational methods, moving from traditional models to hybrid or completely online models at scale. The learnings, derived from practical experience and research, have been explored in EMOOCs 2021 in six tracks and additional workshops, covering various aspects of this field. In this publication, we present papers from the conference's Experience Track, the Policy Track, the Business Track, the International Track, and the Workshops.},
language = {en}
}
@article{HuangRichterKleickmannetal.2021,
author = {Huang, Yizhen and Richter, Eric and Kleickmann, Thilo and Wiepke, Axel and Richter, Dirk},
title = {Classroom complexity affects student teachers' behavior in a VR classroom},
series = {Computers \& education : an international journal},
volume = {163},
journal = {Computers \& education : an international journal},
publisher = {Elsevier},
address = {Oxford},
issn = {0360-1315},
doi = {10.1016/j.compedu.2020.104100},
pages = {15},
year = {2021},
abstract = {Student teachers often struggle to keep track of everything that is happening in the classroom, and particularly to notice and respond when students cause disruptions. The complexity of the classroom environment is a potential contributing factor that has not been empirically tested. In this experimental study, we utilized a virtual reality (VR) classroom to examine whether classroom complexity affects the likelihood of student teachers noticing disruptions and how they react after noticing. Classroom complexity was operationalized as the number of disruptions and the existence of overlapping disruptions (multidimensionality) as well as the existence of parallel teaching tasks (simultaneity). Results showed that student teachers (n = 50) were less likely to notice the scripted disruptions, and also less likely to respond to the disruptions in a comprehensive and effortful manner when facing greater complexity. These results may have implications for both teacher training and the design of VR for training or research purpose. This study contributes to the field from two aspects: 1) it revealed how features of the classroom environment can affect student teachers' noticing of and reaction to disruptions; and 2) it extends the functionality of the VR environment-from a teacher training tool to a testbed of fundamental classroom processes that are difficult to manipulate in real-life.},
language = {en}
}
@phdthesis{Hecher2021,
author = {Hecher, Markus},
title = {Advanced tools and methods for treewidth-based problem solving},
doi = {10.25932/publishup-51251},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-512519},
school = {Universit{\"a}t Potsdam},
pages = {xv, 184},
year = {2021},
abstract = {In the last decades, there was a notable progress in solving the well-known Boolean satisfiability (Sat) problem, which can be witnessed by powerful Sat solvers. One of the reasons why these solvers are so fast are structural properties of instances that are utilized by the solver's interna. This thesis deals with the well-studied structural property treewidth, which measures the closeness of an instance to being a tree. In fact, there are many problems parameterized by treewidth that are solvable in polynomial time in the instance size when parameterized by treewidth. In this work, we study advanced treewidth-based methods and tools for problems in knowledge representation and reasoning (KR). Thereby, we provide means to establish precise runtime results (upper bounds) for canonical problems relevant to KR. Then, we present a new type of problem reduction, which we call decomposition-guided (DG) that allows us to precisely monitor the treewidth when reducing from one problem to another problem. This new reduction type will be the basis for a long-open lower bound result for quantified Boolean formulas and allows us to design a new methodology for establishing runtime lower bounds for problems parameterized by treewidth. Finally, despite these lower bounds, we provide an efficient implementation of algorithms that adhere to treewidth. Our approach finds suitable abstractions of instances, which are subsequently refined in a recursive fashion, and it uses Sat solvers for solving subproblems. It turns out that our resulting solver is quite competitive for two canonical counting problems related to Sat.},
language = {en}
}
@article{HaarmannHolfterPufahletal.2021,
author = {Haarmann, Stephan and Holfter, Adrian and Pufahl, Luise and Weske, Mathias},
title = {Formal framework for checking compliance of data-driven case management},
series = {Journal on data semantics : JoDS},
volume = {10},
journal = {Journal on data semantics : JoDS},
number = {1-2},
publisher = {Springer},
address = {Heidelberg},
issn = {1861-2032},
doi = {10.1007/s13740-021-00120-3},
pages = {143 -- 163},
year = {2021},
abstract = {Business processes are often specified in descriptive or normative models. Both types of models should adhere to internal and external regulations, such as company guidelines or laws. Employing compliance checking techniques, it is possible to verify process models against rules. While traditionally compliance checking focuses on well-structured processes, we address case management scenarios. In case management, knowledge workers drive multi-variant and adaptive processes. Our contribution is based on the fragment-based case management approach, which splits a process into a set of fragments. The fragments are synchronized through shared data but can, otherwise, be dynamically instantiated and executed. We formalize case models using Petri nets. We demonstrate the formalization for design-time and run-time compliance checking and present a proof-of-concept implementation. The application of the implemented compliance checking approach to a use case exemplifies its effectiveness while designing a case model. The empirical evaluation on a set of case models for measuring the performance of the approach shows that rules can often be checked in less than a second.},
language = {en}
}
@article{GoebelLagodzinskiSeidel2021,
author = {G{\"o}bel, Andreas and Lagodzinski, Gregor J. A. and Seidel, Karen},
title = {Counting homomorphisms to trees modulo a prime},
series = {ACM transactions on computation theory : TOCT / Association for Computing Machinery},
volume = {13},
journal = {ACM transactions on computation theory : TOCT / Association for Computing Machinery},
number = {3},
publisher = {Association for Computing Machinery},
address = {New York},
issn = {1942-3454},
doi = {10.1145/3460958},
pages = {1 -- 33},
year = {2021},
abstract = {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.
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.},
language = {en}
}
@article{GruenerMuehleMeinel2021,
author = {Gr{\"u}ner, Andreas and M{\"u}hle, Alexander and Meinel, Christoph},
title = {ATIB},
series = {IEEE access : practical research, open solutions / Institute of Electrical and Electronics Engineers},
volume = {9},
journal = {IEEE access : practical research, open solutions / Institute of Electrical and Electronics Engineers},
publisher = {Institute of Electrical and Electronics Engineers},
address = {New York, NY},
issn = {2169-3536},
doi = {10.1109/ACCESS.2021.3116095},
pages = {138553 -- 138570},
year = {2021},
abstract = {Identity management is a principle component of securing online services. In the advancement of traditional identity management patterns, the identity provider remained a Trusted Third Party (TTP). The service provider and the user need to trust a particular identity provider for correct attributes amongst other demands. This paradigm changed with the invention of blockchain-based Self-Sovereign Identity (SSI) solutions that primarily focus on the users. SSI reduces the functional scope of the identity provider to an attribute provider while enabling attribute aggregation. Besides that, the development of new protocols, disregarding established protocols and a significantly fragmented landscape of SSI solutions pose considerable challenges for an adoption by service providers. We propose an Attribute Trust-enhancing Identity Broker (ATIB) to leverage the potential of SSI for trust-enhancing attribute aggregation. Furthermore, ATIB abstracts from a dedicated SSI solution and offers standard protocols. Therefore, it facilitates the adoption by service providers. Despite the brokered integration approach, we show that ATIB provides a high security posture. Additionally, ATIB does not compromise the ten foundational SSI principles for the users.},
language = {en}
}
@article{GautamZhangLandwehretal.2021,
author = {Gautam, Khem Raj and Zhang, Guoqiang and Landwehr, Niels and Adolphs, Julian},
title = {Machine learning for improvement of thermal conditions inside a hybrid ventilated animal building},
series = {Computers and electronics in agriculture : COMPAG online ; an international journal},
volume = {187},
journal = {Computers and electronics in agriculture : COMPAG online ; an international journal},
publisher = {Elsevier Science},
address = {Amsterdam [u.a.]},
issn = {0168-1699},
doi = {10.1016/j.compag.2021.106259},
pages = {10},
year = {2021},
abstract = {In buildings with hybrid ventilation, natural ventilation opening positions (windows), mechanical ventilation rates, heating, and cooling are manipulated to maintain desired thermal conditions. The indoor temperature is regulated solely by ventilation (natural and mechanical) when the external conditions are favorable to save external heating and cooling energy. The ventilation parameters are determined by a rule-based control scheme, which is not optimal. This study proposes a methodology to enable real-time optimum control of ventilation parameters. We developed offline prediction models to estimate future thermal conditions from the data collected from building in operation. The developed offline model is then used to find the optimal controllable ventilation parameters in real-time to minimize the setpoint deviation in the building. With the proposed methodology, the experimental building's setpoint deviation improved for 87\% of time, on average, by 0.53 degrees C compared to the current deviations.},
language = {en}
}
@article{FreitasdaCruzPfahringerMartensenetal.2021,
author = {Freitas da Cruz, Harry and Pfahringer, Boris and Martensen, Tom and Schneider, Frederic and Meyer, Alexander and B{\"o}ttinger, Erwin and Schapranow, Matthieu-Patrick},
title = {Using interpretability approaches to update "black-box" clinical prediction models},
series = {Artificial intelligence in medicine : AIM},
volume = {111},
journal = {Artificial intelligence in medicine : AIM},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0933-3657},
doi = {10.1016/j.artmed.2020.101982},
pages = {13},
year = {2021},
abstract = {Despite advances in machine learning-based clinical prediction models, only few of such models are actually deployed in clinical contexts. Among other reasons, this is due to a lack of validation studies. In this paper, we present and discuss the validation results of a machine learning model for the prediction of acute kidney injury in cardiac surgery patients initially developed on the MIMIC-III dataset when applied to an external cohort of an American research hospital. To help account for the performance differences observed, we utilized interpretability methods based on feature importance, which allowed experts to scrutinize model behavior both at the global and local level, making it possible to gain further insights into why it did not behave as expected on the validation cohort. The knowledge gleaned upon derivation can be potentially useful to assist model update during validation for more generalizable and simpler models. We argue that interpretability methods should be considered by practitioners as a further tool to help explain performance differences and inform model update in validation studies.},
language = {en}
}
@article{FandinnoLaferriereRomeroetal.2021,
author = {Fandinno, Jorge and Laferriere, Francois and Romero, Javier and Schaub, Torsten H. and Son, Tran Cao},
title = {Planning with incomplete information in quantified answer set programming},
series = {Theory and practice of logic programming},
volume = {21},
journal = {Theory and practice of logic programming},
number = {5},
publisher = {Cambridge University Press},
address = {Cambridge},
issn = {1471-0684},
doi = {10.1017/S1471068421000259},
pages = {663 -- 679},
year = {2021},
abstract = {We present a general approach to planning with incomplete information in Answer Set Programming (ASP). More precisely, we consider the problems of conformant and conditional planning with sensing actions and assumptions. We represent planning problems using a simple formalism where logic programs describe the transition function between states, the initial states and the goal states. For solving planning problems, we use Quantified Answer Set Programming (QASP), an extension of ASP with existential and universal quantifiers over atoms that is analogous to Quantified Boolean Formulas (QBFs). We define the language of quantified logic programs and use it to represent the solutions different variants of conformant and conditional planning. On the practical side, we present a translation-based QASP solver that converts quantified logic programs into QBFs and then executes a QBF solver, and we evaluate experimentally the approach on conformant and conditional planning benchmarks.},
language = {en}
}
@article{DoerrKrejca2021,
author = {Doerr, Benjamin and Krejca, Martin Stefan},
title = {A simplified run time analysis of the univariate marginal distribution algorithm on LeadingOnes},
series = {Theoretical computer science},
volume = {851},
journal = {Theoretical computer science},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0304-3975},
doi = {10.1016/j.tcs.2020.11.028},
pages = {121 -- 128},
year = {2021},
abstract = {With elementary means, we prove a stronger run time guarantee for the univariate marginal distribution algorithm (UMDA) optimizing the LEADINGONES benchmark function in the desirable regime with low genetic drift. If the population size is at least quasilinear, then, with high probability, the UMDA samples the optimum in a number of iterations that is linear in the problem size divided by the logarithm of the UMDA's selection rate. This improves over the previous guarantee, obtained by Dang and Lehre (2015) via the deep level-based population method, both in terms of the run time and by demonstrating further run time gains from small selection rates. Under similar assumptions, we prove a lower bound that matches our upper bound up to constant factors.},
language = {en}
}
@article{DeFreitasJohnsonGoldenetal.2021,
author = {De Freitas, Jessica K. and Johnson, Kipp W. and Golden, Eddye and Nadkarni, Girish N. and Dudley, Joel T. and B{\"o}ttinger, Erwin and Glicksberg, Benjamin S. and Miotto, Riccardo},
title = {Phe2vec},
series = {Patterns},
volume = {2},
journal = {Patterns},
number = {9},
publisher = {Elsevier},
address = {Amsterdam},
issn = {2666-3899},
doi = {10.1016/j.patter.2021.100337},
pages = {9},
year = {2021},
abstract = {Robust phenotyping of patients from electronic health records (EHRs) at scale is a challenge in clinical informatics. Here, we introduce Phe2vec, an automated framework for disease phenotyping from EHRs based on unsupervised learning and assess its effectiveness against standard rule-based algorithms from Phenotype KnowledgeBase (PheKB). Phe2vec is based on pre-computing embeddings of medical concepts and patients' clinical history. Disease phenotypes are then derived from a seed concept and its neighbors in the embedding space. Patients are linked to a disease if their embedded representation is close to the disease phenotype. Comparing Phe2vec and PheKB cohorts head-to-head using chart review, Phe2vec performed on par or better in nine out of ten diseases. Differently from other approaches, it can scale to any condition and was validated against widely adopted expert-based standards. Phe2vec aims to optimize clinical informatics research by augmenting current frameworks to characterize patients by condition and derive reliable disease cohorts.},
language = {en}
}
@article{CsehKavitha2021,
author = {Cseh, {\´A}gnes and Kavitha, Telikepalli},
title = {Popular matchings in complete graphs},
series = {Algorithmica : an international journal in computer science},
volume = {83},
journal = {Algorithmica : an international journal in computer science},
number = {5},
publisher = {Springer},
address = {New York},
issn = {0178-4617},
doi = {10.1007/s00453-020-00791-7},
pages = {1493 -- 1523},
year = {2021},
abstract = {Our input is a complete graph G on n vertices where each vertex has a strict ranking of all other vertices in G. The goal is to construct a matching in G that is popular. A matching M is popular if M does not lose a head-to-head election against any matching M ': here each vertex casts a vote for the matching in {M,M '} in which it gets a better assignment. Popular matchings need not exist in the given instance G and the popular matching problem is to decide whether one exists or not. The popular matching problem in G is easy to solve for odd n. Surprisingly, the problem becomes NP-complete for even n, as we show here. This is one of the few graph theoretic problems efficiently solvable when n has one parity and NP-complete when n has the other parity.},
language = {en}
}
@article{CsehJuhos2021,
author = {Cseh, {\´A}gnes and Juhos, Attila},
title = {Pairwise preferences in the stable marriage problem},
series = {ACM Transactions on Economics and Computation / Association for Computing Machinery},
volume = {9},
journal = {ACM Transactions on Economics and Computation / Association for Computing Machinery},
number = {1},
publisher = {Association for Computing Machinery},
address = {New York},
issn = {2167-8375},
doi = {10.1145/3434427},
pages = {28},
year = {2021},
abstract = {We study the classical, two-sided stable marriage problem under pairwise preferences. In the most general setting, agents are allowed to express their preferences as comparisons of any two of their edges, and they also have the right to declare a draw or even withdraw from such a comparison. This freedom is then gradually restricted as we specify six stages of orderedness in the preferences, ending with the classical case of strictly ordered lists. We study all cases occurring when combining the three known notions of stability-weak, strong, and super-stability-under the assumption that each side of the bipartite market obtains one of the six degrees of orderedness. By designing three polynomial algorithms and two NP-completeness proofs, we determine the complexity of all cases not yet known and thus give an exact boundary in terms of preference structure between tractable and intractable cases.},
language = {en}
}
@article{CombiOliboniWeskeetal.2021,
author = {Combi, Carlo and Oliboni, Barbara and Weske, Mathias and Zerbato, Francesca},
title = {Seamless conceptual modeling of processes with transactional and analytical data},
series = {Data \& knowledge engineering},
volume = {134},
journal = {Data \& knowledge engineering},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0169-023X},
doi = {10.1016/j.datak.2021.101895},
pages = {14},
year = {2021},
abstract = {In the field of Business Process Management (BPM), modeling business processes and related data is a critical issue since process activities need to manage data stored in databases. The connection between processes and data is usually handled at the implementation level, even if modeling both processes and data at the conceptual level should help designers in improving business process models and identifying requirements for implementation. Especially in data -and decision-intensive contexts, business process activities need to access data stored both in databases and data warehouses. In this paper, we complete our approach for defining a novel conceptual view that bridges process activities and data. The proposed approach allows the designer to model the connection between business processes and database models and define the operations to perform, providing interesting insights on the overall connected perspective and hints for identifying activities that are crucial for decision support.},
language = {en}
}
@article{BredeBotta2021,
author = {Brede, Nuria and Botta, Nicola},
title = {On the correctness of monadic backward induction},
series = {Journal of functional programming},
volume = {31},
journal = {Journal of functional programming},
publisher = {Cambridge University Press},
address = {Cambridge},
issn = {1469-7653},
doi = {10.1017/S0956796821000228},
pages = {39},
year = {2021},
abstract = {In control theory, to solve a finite-horizon sequential decision problem (SDP) commonly means to find a list of decision rules that result in an optimal expected total reward (or cost) when taking a given number of decision steps. SDPs are routinely solved using Bellman's backward induction. Textbook authors (e.g. Bertsekas or Puterman) typically give more or less formal proofs to show that the backward induction algorithm is correct as solution method for deterministic and stochastic SDPs. Botta, Jansson and Ionescu propose a generic framework for finite horizon, monadic SDPs together with a monadic version of backward induction for solving such SDPs. In monadic SDPs, the monad captures a generic notion of uncertainty, while a generic measure function aggregates rewards. In the present paper, we define a notion of correctness for monadic SDPs and identify three conditions that allow us to prove a correctness result for monadic backward induction that is comparable to textbook correctness proofs for ordinary backward induction. The conditions that we impose are fairly general and can be cast in category-theoretical terms using the notion of Eilenberg-Moore algebra. They hold in familiar settings like those of deterministic or stochastic SDPs, but we also give examples in which they fail. Our results show that backward induction can safely be employed for a broader class of SDPs than usually treated in textbooks. However, they also rule out certain instances that were considered admissible in the context of Botta et al. 's generic framework. Our development is formalised in Idris as an extension of the Botta et al. framework and the sources are available as supplementary material.},
language = {en}
}
@article{BordihnVaszil2021,
author = {Bordihn, Henning and Vaszil, Gy{\"o}rgy},
title = {Reversible parallel communicating finite automata systems},
series = {Acta informatica},
volume = {58},
journal = {Acta informatica},
number = {4},
publisher = {Springer},
address = {Berlin ; Heidelberg ; New York, NY},
issn = {0001-5903},
doi = {10.1007/s00236-021-00396-9},
pages = {263 -- 279},
year = {2021},
abstract = {We study the concept of reversibility in connection with parallel communicating systems of finite automata (PCFA in short). We define the notion of reversibility in the case of PCFA (also covering the non-deterministic case) and discuss the relationship of the reversibility of the systems and the reversibility of its components. We show that a system can be reversible with non-reversible components, and the other way around, the reversibility of the components does not necessarily imply the reversibility of the system as a whole. We also investigate the computational power of deterministic centralized reversible PCFA. We show that these very simple types of PCFA (returning or non-returning) can recognize regular languages which cannot be accepted by reversible (deterministic) finite automata, and that they can even accept languages that are not context-free. We also separate the deterministic and non-deterministic variants in the case of systems with non-returning communication. We show that there are languages accepted by non-deterministic centralized PCFA, which cannot be recognized by any deterministic variant of the same type.},
language = {en}
}
@article{BordihnHolzer2021,
author = {Bordihn, Henning and Holzer, Markus},
title = {On the number of active states in finite automata},
series = {Acta informatica},
volume = {58},
journal = {Acta informatica},
number = {4},
publisher = {Springer},
address = {Berlin ; Heidelberg [u.a.]},
issn = {0001-5903},
doi = {10.1007/s00236-021-00397-8},
pages = {301 -- 318},
year = {2021},
abstract = {We introduce a new measure of descriptional complexity on finite automata, called the number of active states. Roughly speaking, the number of active states of an automaton A on input w counts the number of different states visited during the most economic computation of the automaton A for the word w. This concept generalizes to finite automata and regular languages in a straightforward way. We show that the number of active states of both finite automata and regular languages is computable, even with respect to nondeterministic finite automata. We further compare the number of active states to related measures for regular languages. In particular, we show incomparability to the radius of regular languages and that the difference between the number of active states and the total number of states needed in finite automata for a regular language can be of exponential order.},
language = {en}
}
@article{BorchertMockTomczaketal.2021,
author = {Borchert, Florian and Mock, Andreas and Tomczak, Aurelie and H{\"u}gel, Jonas and Alkarkoukly, Samer and Knurr, Alexander and Volckmar, Anna-Lena and Stenzinger, Albrecht and Schirmacher, Peter and Debus, J{\"u}rgen and J{\"a}ger, Dirk and Longerich, Thomas and Fr{\"o}hling, Stefan and Eils, Roland and Bougatf, Nina and Sax, Ulrich and Schapranow, Matthieu-Patrick},
title = {Correction to: Knowledge bases and software support for variant interpretation in precision oncology},
series = {Briefings in bioinformatics},
volume = {22},
journal = {Briefings in bioinformatics},
number = {6},
publisher = {Oxford Univ. Press},
address = {Oxford},
issn = {1467-5463},
doi = {10.1093/bib/bbab246},
pages = {1},
year = {2021},
language = {en}
}
@article{BorchertMockTomczaketal.2021,
author = {Borchert, Florian and Mock, Andreas and Tomczak, Aurelie and H{\"u}gel, Jonas and Alkarkoukly, Samer and Knurr, Alexander and Volckmar, Anna-Lena and Stenzinger, Albrecht and Schirmacher, Peter and Debus, J{\"u}rgen and J{\"a}ger, Dirk and Longerich, Thomas and Fr{\"o}hling, Stefan and Eils, Roland and Bougatf, Nina and Sax, Ulrich and Schapranow, Matthieu-Patrick},
title = {Knowledge bases and software support for variant interpretation in precision oncology},
series = {Briefings in bioinformatics},
volume = {22},
journal = {Briefings in bioinformatics},
number = {6},
publisher = {Oxford Univ. Press},
address = {Oxford},
issn = {1467-5463},
doi = {10.1093/bib/bbab134},
pages = {17},
year = {2021},
abstract = {Precision oncology is a rapidly evolving interdisciplinary medical specialty. Comprehensive cancer panels are becoming increasingly available at pathology departments worldwide, creating the urgent need for scalable cancer variant annotation and molecularly informed treatment recommendations. A wealth of mainly academia-driven knowledge bases calls for software tools supporting the multi-step diagnostic process. We derive a comprehensive list of knowledge bases relevant for variant interpretation by a review of existing literature followed by a survey among medical experts from university hospitals in Germany. In addition, we review cancer variant interpretation tools, which integrate multiple knowledge bases. We categorize the knowledge bases along the diagnostic process in precision oncology and analyze programmatic access options as well as the integration of knowledge bases into software tools. The most commonly used knowledge bases provide good programmatic access options and have been integrated into a range of software tools. For the wider set of knowledge bases, access options vary across different parts of the diagnostic process. Programmatic access is limited for information regarding clinical classifications of variants and for therapy recommendations. The main issue for databases used for biological classification of pathogenic variants and pathway context information is the lack of standardized interfaces. There is no single cancer variant interpretation tool that integrates all identified knowledge bases. Specialized tools are available and need to be further developed for different steps in the diagnostic process.},
language = {en}
}
@article{BonnetDongNaumannetal.2021,
author = {Bonnet, Philippe and Dong, Xin Luna and Naumann, Felix and T{\"o}z{\"u}n, P{\i}nar},
title = {VLDB 2021},
series = {SIGMOD record},
volume = {50},
journal = {SIGMOD record},
number = {4},
publisher = {Association for Computing Machinery},
address = {New York},
issn = {0163-5808},
doi = {10.1145/3516431.3516447},
pages = {50 -- 53},
year = {2021},
abstract = {The 47th International Conference on Very Large Databases (VLDB'21) was held on August 16-20, 2021 as a hybrid conference. It attracted 180 in-person attendees in Copenhagen and 840 remote attendees. In this paper, we describe our key decisions as general chairs and program committee chairs and share the lessons we learned.},
language = {en}
}
@article{Boissier2021,
author = {Boissier, Martin},
title = {Robust and budget-constrained encoding configurations for in-memory database systems},
series = {Proceedings of the VLDB Endowment},
volume = {15},
journal = {Proceedings of the VLDB Endowment},
number = {4},
publisher = {Association for Computing Machinery (ACM)},
address = {[New York]},
issn = {2150-8097},
doi = {10.14778/3503585.3503588},
pages = {780 -- 793},
year = {2021},
abstract = {Data encoding has been applied to database systems for decades as it mitigates bandwidth bottlenecks and reduces storage requirements. But even in the presence of these advantages, most in-memory database systems use data encoding only conservatively as the negative impact on runtime performance can be severe. Real-world systems with large parts being infrequently accessed and cost efficiency constraints in cloud environments require solutions that automatically and efficiently select encoding techniques, including heavy-weight compression. In this paper, we introduce workload-driven approaches to automaticaly determine memory budget-constrained encoding configurations using greedy heuristics and linear programming. We show for TPC-H, TPC-DS, and the Join Order Benchmark that optimized encoding configurations can reduce the main memory footprint significantly without a loss in runtime performance over state-of-the-art dictionary encoding. To yield robust selections, we extend the linear programming-based approach to incorporate query runtime constraints and mitigate unexpected performance regressions.},
language = {en}
}
@misc{BensonMakaitRabl2021,
author = {Benson, Lawrence and Makait, Hendrik and Rabl, Tilmann},
title = {Viper},
series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Reihe der Digital Engineering Fakult{\"a}t},
journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Reihe der Digital Engineering Fakult{\"a}t},
number = {9},
issn = {2150-8097},
doi = {10.25932/publishup-55966},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-559664},
pages = {15},
year = {2021},
abstract = {Key-value stores (KVSs) have found wide application in modern software systems. For persistence, their data resides in slow secondary storage, which requires KVSs to employ various techniques to increase their read and write performance from and to the underlying medium. Emerging persistent memory (PMem) technologies offer data persistence at close-to-DRAM speed, making them a promising alternative to classical disk-based storage. However, simply drop-in replacing existing storage with PMem does not yield good results, as block-based access behaves differently in PMem than on disk and ignores PMem's byte addressability, layout, and unique performance characteristics. In this paper, we propose three PMem-specific access patterns and implement them in a hybrid PMem-DRAM KVS called Viper. We employ a DRAM-based hash index and a PMem-aware storage layout to utilize the random-write speed of DRAM and efficient sequential-write performance PMem. Our evaluation shows that Viper significantly outperforms existing KVSs for core KVS operations while providing full data persistence. Moreover, Viper outperforms existing PMem-only, hybrid, and disk-based KVSs by 4-18x for write workloads, while matching or surpassing their get performance.},
language = {en}
}
@article{BensonMakaitRabl2021,
author = {Benson, Lawrence and Makait, Hendrik and Rabl, Tilmann},
title = {Viper},
series = {Proceedings of the VLDB Endowment},
volume = {14},
journal = {Proceedings of the VLDB Endowment},
number = {9},
publisher = {Association for Computing Machinery},
address = {New York},
issn = {2150-8097},
doi = {10.14778/3461535.3461543},
pages = {1544 -- 1556},
year = {2021},
abstract = {Key-value stores (KVSs) have found wide application in modern software systems. For persistence, their data resides in slow secondary storage, which requires KVSs to employ various techniques to increase their read and write performance from and to the underlying medium. Emerging persistent memory (PMem) technologies offer data persistence at close-to-DRAM speed, making them a promising alternative to classical disk-based storage. However, simply drop-in replacing existing storage with PMem does not yield good results, as block-based access behaves differently in PMem than on disk and ignores PMem's byte addressability, layout, and unique performance characteristics. In this paper, we propose three PMem-specific access patterns and implement them in a hybrid PMem-DRAM KVS called Viper. We employ a DRAM-based hash index and a PMem-aware storage layout to utilize the random-write speed of DRAM and efficient sequential-write performance PMem. Our evaluation shows that Viper significantly outperforms existing KVSs for core KVS operations while providing full data persistence. Moreover, Viper outperforms existing PMem-only, hybrid, and disk-based KVSs by 4-18x for write workloads, while matching or surpassing their get performance.},
language = {en}
}
@book{BartzKrestel2021,
author = {Bartz, Christian and Krestel, Ralf},
title = {Deep learning for computer vision in the art domain},
number = {139},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-514-9},
issn = {1613-5652},
doi = {10.25932/publishup-51290},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-512906},
publisher = {Universit{\"a}t Potsdam},
pages = {vii, 79},
year = {2021},
abstract = {In recent years, computer vision algorithms based on machine learning have seen rapid development. In the past, research mostly focused on solving computer vision problems such as image classification or object detection on images displaying natural scenes. Nowadays other fields such as the field of cultural heritage, where an abundance of data is available, also get into the focus of research. In the line of current research endeavours, we collaborated with the Getty Research Institute which provided us with a challenging dataset, containing images of paintings and drawings. In this technical report, we present the results of the seminar "Deep Learning for Computer Vision". In this seminar, students of the Hasso Plattner Institute evaluated state-of-the-art approaches for image classification, object detection and image recognition on the dataset of the Getty Research Institute. The main challenge when applying modern computer vision methods to the available data is the availability of annotated training data, as the dataset provided by the Getty Research Institute does not contain a sufficient amount of annotated samples for the training of deep neural networks. However, throughout the report we show that it is possible to achieve satisfying to very good results, when using further publicly available datasets, such as the WikiArt dataset, for the training of machine learning models.},
language = {en}
}
@book{BaltzerHradilakPfennigschmidtetal.2021,
author = {Baltzer, Wanda and Hradilak, Theresa and Pfennigschmidt, Lara and Prestin, Luc Maurice and Spranger, Moritz and Stadlinger, Simon and Wendt, Leo and Lincke, Jens and Rein, Patrick and Church, Luke and Hirschfeld, Robert},
title = {An individual-centered approach to visualize people's opinions and demographic information},
number = {136},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-504-0},
issn = {1613-5652},
doi = {10.25932/publishup-49145},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-491457},
publisher = {Universit{\"a}t Potsdam},
pages = {326},
year = {2021},
abstract = {The noble way to substantiate decisions that affect many people is to ask these people for their opinions. For governments that run whole countries, this means asking all citizens for their views to consider their situations and needs. Organizations such as Africa's Voices Foundation, who want to facilitate communication between decision-makers and citizens of a country, have difficulty mediating between these groups. To enable understanding, statements need to be summarized and visualized. Accomplishing these goals in a way that does justice to the citizens' voices and situations proves challenging. Standard charts do not help this cause as they fail to create empathy for the people behind their graphical abstractions. Furthermore, these charts do not create trust in the data they are representing as there is no way to see or navigate back to the underlying code and the original data. To fulfill these functions, visualizations would highly benefit from interactions to explore the displayed data, which standard charts often only limitedly provide. To help improve the understanding of people's voices, we developed and categorized 80 ideas for new visualizations, new interactions, and better connections between different charts, which we present in this report. From those ideas, we implemented 10 prototypes and two systems that integrate different visualizations. We show that this integration allows consistent appearance and behavior of visualizations. The visualizations all share the same main concept: representing each individual with a single dot. To realize this idea, we discuss technologies that efficiently allow the rendering of a large number of these dots. With these visualizations, direct interactions with representations of individuals are achievable by clicking on them or by dragging a selection around them. This direct interaction is only possible with a bidirectional connection from the visualization to the data it displays. We discuss different strategies for bidirectional mappings and the trade-offs involved. Having unified behavior across visualizations enhances exploration. For our prototypes, that includes grouping, filtering, highlighting, and coloring of dots. Our prototyping work was enabled by the development environment Lively4. We explain which parts of Lively4 facilitated our prototyping process. Finally, we evaluate our approach to domain problems and our developed visualization concepts. Our work provides inspiration and a starting point for visualization development in this domain. Our visualizations can improve communication between citizens and their government and motivate empathetic decisions. Our approach, combining low-level entities to create visualizations, provides value to an explorative and empathetic workflow. We show that the design space for visualizing this kind of data has a lot of potential and that it is possible to combine qualitative and quantitative approaches to data analysis.},
language = {en}
}
@article{AyzelHeistermann2021,
author = {Ayzel, Georgy and Heistermann, Maik},
title = {The effect of calibration data length on the performance of a conceptual hydrological model versus LSTM and GRU},
series = {Computers \& geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology},
volume = {149},
journal = {Computers \& geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0098-3004},
doi = {10.1016/j.cageo.2021.104708},
pages = {12},
year = {2021},
abstract = {We systematically explore the effect of calibration data length on the performance of a conceptual hydrological model, GR4H, in comparison to two Artificial Neural Network (ANN) architectures: Long Short-Term Memory Networks (LSTM) and Gated Recurrent Units (GRU), which have just recently been introduced to the field of hydrology. We implemented a case study for six river basins across the contiguous United States, with 25 years of meteorological and discharge data. Nine years were reserved for independent validation; two years were used as a warm-up period, one year for each of the calibration and validation periods, respectively; from the remaining 14 years, we sampled increasing amounts of data for model calibration, and found pronounced differences in model performance. While GR4H required less data to converge, LSTM and GRU caught up at a remarkable rate, considering their number of parameters. Also, LSTM and GRU exhibited the higher calibration instability in comparison to GR4H. These findings confirm the potential of modern deep-learning architectures in rainfall runoff modelling, but also highlight the noticeable differences between them in regard to the effect of calibration data length.},
language = {en}
}
@article{AngeleskaOmranianNikoloski2021,
author = {Angeleska, Angela and Omranian, Sara and Nikoloski, Zoran},
title = {Coherent network partitions},
series = {Theoretical computer science : the journal of the EATCS},
volume = {894},
journal = {Theoretical computer science : the journal of the EATCS},
publisher = {Elsevier},
address = {Amsterdam [u.a.]},
issn = {0304-3975},
doi = {10.1016/j.tcs.2021.10.002},
pages = {3 -- 11},
year = {2021},
abstract = {We continue to study coherent partitions of graphs whereby the vertex set is partitioned into subsets that induce biclique spanned subgraphs. The problem of identifying the minimum number of edges to obtain biclique spanned connected components (CNP), called the coherence number, is NP-hard even on bipartite graphs. Here, we propose a graph transformation geared towards obtaining an O (log n)-approximation algorithm for the CNP on a bipartite graph with n vertices. The transformation is inspired by a new characterization of biclique spanned subgraphs. In addition, we study coherent partitions on prime graphs, and show that finding coherent partitions reduces to the problem of finding coherent partitions in a prime graph. Therefore, these results provide future directions for approximation algorithms for the coherence number of a given graph.},
language = {en}
}
@inproceedings{AbramovaGundlachBilda2021,
author = {Abramova, Olga and Gundlach, Jana and Bilda, Juliane},
title = {Understanding the role of newsfeed clutter in stereotype activation},
series = {PACIS 2021 proceedings},
booktitle = {PACIS 2021 proceedings},
number = {473},
publisher = {AIS Electronic Library (AISeL)},
address = {[Erscheinungsort nicht ermittelbar]},
isbn = {978-1-7336325-7-7},
year = {2021},
abstract = {Despite the phenomenal growth of Big Data Analytics in the last few years, little research is done to explicate the relationship between Big Data Analytics Capability (BDAC) and indirect strategic value derived from such digital capabilities. We attempt to address this gap by proposing a conceptual model of the BDAC - Innovation relationship using dynamic capability theory. The work expands on BDAC business value research and extends the nominal research done on BDAC - innovation. We focus on BDAC's relationship with different innovation objects, namely product, business process, and business model innovation, impacting all value chain activities. The insights gained will stimulate academic and practitioner interest in explicating strategic value generated from BDAC and serve as a framework for future research on the subject},
language = {en}
}
@inproceedings{AbramovaGladkayaKrasnova2021,
author = {Abramova, Olga and Gladkaya, Margarita and Krasnova, Hanna},
title = {An unusual encounter with oneself},
series = {ICIS 2021: IS and the future of work},
booktitle = {ICIS 2021: IS and the future of work},
publisher = {AIS Electronic Library (AISeL)},
address = {[Erscheinungsort nicht ermittelbar]},
year = {2021},
abstract = {Helping overcome distance, the use of videoconferencing tools has surged during the pandemic. To shed light on the consequences of videoconferencing at work, this study takes a granular look at the implications of the self-view feature for meeting outcomes. Building on self-awareness research and self-regulation theory, we argue that by heightening the state of self-awareness, self-view engagement depletes participants' mental resources and thereby can undermine online meeting outcomes. Evaluation of our theoretical model on a sample of 179 employees reveals a nuanced picture. Self-view engagement while speaking and while listening is positively associated with self-awareness, which, in turn, is negatively associated with satisfaction with meeting process, perceived productivity, and meeting enjoyment. The criticality of the communication role is put forward: looking at self while listening to other attendees has a negative direct and indirect effect on meeting outcomes; however, looking at self while speaking produces equivocal effects.},
language = {en}
}