TY - JOUR A1 - Liang, Feng A1 - Liu, Yunzhen A1 - Liu, Hai A1 - Ma, Shilong A1 - Schnor, Bettina T1 - A Parallel Job Execution Time Estimation Approach Based on User Submission Patterns within Computational Grids JF - International journal of parallel programming N2 - Scheduling performance in computational grid can potentially benefit a lot from accurate execution time estimation for parallel jobs. Most existing approaches for the parallel job execution time estimation, however, require ample past job traces and the explicit correlations between the job execution time and the outer layout parameters such as the consumed processor numbers, the user-estimated execution time and the job ID, which are hard to obtain or reveal. This paper presents and evaluates a novel execution time estimation approach for parallel jobs, the user-behavior clustering for execution time estimation, which can give more accurate execution time estimation for parallel jobs through exploring the job similarity and revealing the user submission patterns. Experiment results show that compared to the state-of-art algorithms, our approach can improve the accuracy of the job execution time estimation up to 5.6 %, meanwhile the time that our approach spends on calculation can be reduced up to 3.8 %. KW - User submission pattern KW - Parallel job execution time estimation KW - Computational grid Y1 - 2015 U6 - https://doi.org/10.1007/s10766-013-0294-1 SN - 0885-7458 SN - 1573-7640 VL - 43 IS - 3 SP - 440 EP - 454 PB - Springer CY - New York ER - TY - JOUR A1 - Jung, Jörg A1 - Kiertscher, Simon A1 - Menski, Sebastian A1 - Schnor, Bettina T1 - Self-Adapting Load Balancing for DNS JF - Journal of networks N2 - The Domain Name System belongs to the core services of the Internet infrastructure. Hence, DNS availability and performance is essential for the operation of the Internet and replication as well as load balancing are used for the root and top level name servers. This paper proposes an architecture for credit based server load balancing (SLB) for DNS. Compared to traditional load balancing algorithms like round robin or least connection, the benefit of credit based SLB is that the load balancer can adapt more easily to heterogeneous load requests and back end server capacities. The challenge of this approach is the definition of a suited credit metric. While this was done before for TCP based services like HTTP, the problem was not solved for UDP based services like DNS. In the following an approach is presented to define credits also for UDP based services. This UDP/DNS approach is implemented within the credit based SLB implementation salbnet. The presented measurements confirm the benefit of the self-adapting credit based SLB approach. In our experiments, the mean (first) response time dropped significantly compared to weighted round robin (WRR) (from over 4 ms to about 0.6 ms for dynamic pressure relieve (DPR)). KW - Load Balancing KW - Cluster Computing KW - Performance Evaluation Y1 - 2015 U6 - https://doi.org/10.1109/SPECTS.2014.6879994 VL - 10 IS - 4 SP - 222 EP - 231 PB - Kluwer Academic Publishers CY - Oulu ER - TY - JOUR A1 - Pablo Alarcon, Pedro A1 - Arroyo, Fernando A1 - Bordihn, Henning A1 - Mitrana, Victor A1 - Mueller, Mike T1 - Ambiguity of the multiple interpretations on regular languages JF - Fundamenta informaticae N2 - A multiple interpretation scheme is an ordered sequence of morphisms. The ordered multiple interpretation of a word is obtained by concatenating the images of that word in the given order of morphisms. The arbitrary multiple interpretation of a word is the semigroup generated by the images of that word. These interpretations are naturally extended to languages. Four types of ambiguity of multiple interpretation schemata on a language are defined: o-ambiguity, internal ambiguity, weakly external ambiguity and strongly external ambiguity. We investigate the problem of deciding whether a multiple interpretation scheme is ambiguous on regular languages. KW - Multiple interpretation scheme KW - regular language KW - o-ambiguity KW - internal ambiguity KW - external ambiguity Y1 - 2015 U6 - https://doi.org/10.3233/FI-2015-1200 SN - 0169-2968 SN - 1875-8681 VL - 138 IS - 1-2 SP - 85 EP - 95 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Childs, Dorothee A1 - Grimbs, Sergio A1 - Selbig, Joachim T1 - Refined elasticity sampling for Monte Carlo-based identification of stabilizing network patterns JF - Bioinformatics N2 - Motivation: Structural kinetic modelling (SKM) is a framework to analyse whether a metabolic steady state remains stable under perturbation, without requiring detailed knowledge about individual rate equations. It provides a representation of the system's Jacobian matrix that depends solely on the network structure, steady state measurements, and the elasticities at the steady state. For a measured steady state, stability criteria can be derived by generating a large number of SKMs with randomly sampled elasticities and evaluating the resulting Jacobian matrices. The elasticity space can be analysed statistically in order to detect network positions that contribute significantly to the perturbation response. Here, we extend this approach by examining the kinetic feasibility of the elasticity combinations created during Monte Carlo sampling. Results: Using a set of small example systems, we show that the majority of sampled SKMs would yield negative kinetic parameters if they were translated back into kinetic models. To overcome this problem, a simple criterion is formulated that mitigates such infeasible models. After evaluating the small example pathways, the methodology was used to study two steady states of the neuronal TCA cycle and the intrinsic mechanisms responsible for their stability or instability. The findings of the statistical elasticity analysis confirm that several elasticities are jointly coordinated to control stability and that the main source for potential instabilities are mutations in the enzyme alpha-ketoglutarate dehydrogenase. Y1 - 2015 U6 - https://doi.org/10.1093/bioinformatics/btv243 SN - 1367-4803 SN - 1460-2059 VL - 31 IS - 12 SP - 214 EP - 220 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Lemcke, Stefanie A1 - Haedge, Kora A1 - Zender, Raphael A1 - Lucke, Ulrike T1 - RouteMe: a multilevel pervasive game on mobile ad hoc routing JF - Personal and ubiquitous computing N2 - Pervasive educational games have the potential to transfer learning content to real-life experiences beyond lecture rooms, through realizing field trips in an augmented or virtual manner. This article introduces the pervasive educational game "RouteMe" that brings the rather abstract topic of routing in ad hoc networks to real-world environments. The game is designed for university-level courses and supports these courses in a motivating manner to deepen the learning experience. Students slip into the role of either routing nodes or applications with routing demands. On three consecutive levels of difficulty, they get introduced with the game concept, learn the basic routing mechanisms and become aware of the general limitations and functionality of routing nodes. This paper presents the pedagogical and technical game concept as well as findings from an evaluation in a university setting. KW - E-learning KW - Educational game KW - Mobile application KW - Pervasive computing KW - Location awareness KW - Ad hoc routing KW - AODV Y1 - 2015 U6 - https://doi.org/10.1007/s00779-015-0843-2 SN - 1617-4909 SN - 1617-4917 VL - 19 IS - 3-4 SP - 537 EP - 549 PB - Springer CY - London ER - TY - JOUR A1 - Przybylla, Mareen A1 - Romeike, Ralf T1 - Key Competences with Physical Computing JF - KEYCIT 2014 - Key Competencies in Informatics and ICT N2 - Physical computing covers the design and realization of interactive objects and installations and allows students to develop concrete, tangible products of the real world that arise from the learners’ imagination. This way, constructionist learning is raised to a level that enables students to gain haptic experience and thereby concretizes the virtual. In this paper the defining characteristics of physical computing are described. Key competences to be gained with physical computing will be identified. KW - Defining characteristics of physical computing KW - key competences in physical computing KW - physical computing tools Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-82904 SN - 1868-0844 SN - 2191-1940 IS - 7 SP - 351 EP - 361 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Wegner, Christian A1 - Zender, Raphael A1 - Lucke, Ulrike T1 - ProtoSense BT - Interactive Paper Prototyping with Multi-Touch Tables JF - KEYCIT 2014 - Key Competencies in Informatics and ICT KW - Interface design KW - paper prototyping KW - NUI Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-82970 SN - 1868-0844 SN - 2191-1940 IS - 7 SP - 405 EP - 407 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Lai, Kwok-Wing A1 - Davis, Niki A1 - Eickelmann, Birgit A1 - Erstad, Ola A1 - Fisser, Petra A1 - Gibson, David A1 - Khaddage, Ferial A1 - Knezek, Gerald A1 - Webb, Mary T1 - Tackling Educational Challenges in a Digitally Networked World BT - Strategies developed from the EDUSummIT 2013 JF - KEYCIT 2014 - Key Competencies in Informatics and ICT KW - Assessment KW - computational thinking KW - digitally-enabled pedagogies KW - educational systems KW - informal and formal learning KW - mobile learning KW - mobile technologies and apps KW - organisational evolution Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-82997 SN - 1868-0844 IS - 7 SP - 415 EP - 423 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Walton, Douglas A1 - Gordon, Thomas F. T1 - Formalizing informal logic JF - Informal logic : reasoning and argumentation in theory and practics N2 - In this paper we investigate the extent to which formal argumentation models can handle ten basic characteristics of informal logic identified in the informal logic literature. By showing how almost all of these characteristics can be successfully modelled formally, we claim that good progress can be made toward the project of formalizing informal logic. Of the formal argumentation models available, we chose the Carneades Argumentation System (CAS), a formal, computational model of argument that uses argument graphs as its basis, structures of a kind very familiar to practitioners of informal logic through their use of argument diagrams. KW - informal logic KW - formal argumentation systems KW - real arguments KW - premise acceptability KW - conductive argument KW - RSA triangle KW - relevance KW - sufficiency Y1 - 2015 SN - 0824-2577 VL - 35 IS - 4 SP - 508 EP - 538 PB - Centre for Research in Reasoning, Argumentation and Rhetoric, University of Windsor CY - Windsor ER - TY - JOUR A1 - Fichte, Johannes Klaus A1 - Szeider, Stefan T1 - Backdoors to tractable answer set programming JF - Artificial intelligence N2 - Answer Set Programming (ASP) is an increasingly popular framework for declarative programming that admits the description of problems by means of rules and constraints that form a disjunctive logic program. In particular, many Al problems such as reasoning in a nonmonotonic setting can be directly formulated in ASP. Although the main problems of ASP are of high computational complexity, complete for the second level of the Polynomial Hierarchy, several restrictions of ASP have been identified in the literature, under which ASP problems become tractable. In this paper we use the concept of backdoors to identify new restrictions that make ASP problems tractable. Small backdoors are sets of atoms that represent "clever reasoning shortcuts" through the search space and represent a hidden structure in the problem input. The concept of backdoors is widely used in theoretical investigations in the areas of propositional satisfiability and constraint satisfaction. We show that it can be fruitfully adapted to ASP. We demonstrate how backdoors can serve as a unifying framework that accommodates several tractable restrictions of ASP known from the literature. Furthermore, we show how backdoors allow us to deploy recent algorithmic results from parameterized complexity theory to the domain of answer set programming. (C) 2015 Elsevier B.V. All rights reserved. KW - Answer set programming KW - Backdoors KW - Computational complexity KW - Parameterized complexity KW - Kernelization Y1 - 2015 U6 - https://doi.org/10.1016/j.artint.2014.12.001 SN - 0004-3702 SN - 1872-7921 VL - 220 SP - 64 EP - 103 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ahmad, Nadeem A1 - Shoaib, Umar A1 - Prinetto, Paolo T1 - Usability of Online Assistance From Semiliterate Users' Perspective JF - International journal of human computer interaction Y1 - 2015 U6 - https://doi.org/10.1080/10447318.2014.925772 SN - 1044-7318 SN - 1532-7590 VL - 31 IS - 1 SP - 55 EP - 64 PB - Taylor & Francis Group CY - Philadelphia ER - TY - JOUR A1 - Lamprecht, Anna-Lena A1 - Margaria, Tiziana ED - Lamprecht, Anna-Lena ED - Margaria, Tiziana T1 - Scientific workflows and XMDD JF - Process design for natural scientists Y1 - 2015 SN - 978-3-662-45006-2 SP - 1 EP - 13 PB - Springer CY - Berlin ER - TY - JOUR A1 - Grünewald, Franka A1 - Meinel, Christoph T1 - Implementation and Evaluation of Digital E-Lecture Annotation in Learning Groups to Foster Active Learning JF - IEEE transactions on learning technologies N2 - The use of video lectures in distance learning involves the two major problems of searchability and active user participation. In this paper, we promote the implementation and usage of a collaborative educational video annotation functionality to overcome these two challenges. Different use cases and requirements, as well as details of the implementation, are explained. Furthermore, we suggest more improvements to foster a culture of participation and an algorithm for the extraction of semantic data. Finally, evaluations in the form of user tests and questionnaires in a MOOC setting are presented. The results of the evaluation are promising, as they indicate not only that students perceive it as useful, but also that the learning effectiveness increases. The combination of personal lecture video annotations with a semantic topic map was also evaluated positively and will thus be investigated further, as will the implementation in a MOOC context. KW - eLectures KW - tele-teaching KW - video annotation KW - collaborative learning Y1 - 2015 U6 - https://doi.org/10.1109/TLT.2015.2396042 SN - 1939-1382 VL - 8 IS - 3 SP - 286 EP - 298 PB - Inst. of Electr. and Electronics Engineers CY - Los Alamitos ER - TY - JOUR A1 - Bröker, Kathrin ED - Schubert, Sigrid ED - Schwill, Andreas T1 - Unterstützung Informatik-Studierender durch ein Lernzentrum JF - HDI 2014 : Gestalten von Übergängen N2 - In diesem Papier wird das Konzept eines Lernzentrums für die Informatik (LZI) an der Universität Paderborn vorgestellt. Ausgehend von den fachspezifischen Schwierigkeiten der Informatik Studierenden werden die Angebote des LZIs erläutert, die sich über die vier Bereiche Individuelle Beratung und Betreuung, „Offener Lernraum“, Workshops und Lehrveranstaltungen sowie Forschung erstrecken. Eine erste Evaluation mittels Feedbackbögen zeigt, dass das Angebot bei den Studierenden positiv aufgenommen wird. Zukünftig soll das Angebot des LZIs weiter ausgebaut und verbessert werden. Ausgangsbasis dazu sind weitere Studien. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-84754 VL - 2015 IS - 9 SP - 189 EP - 197 ER - TY - JOUR A1 - Omranian, Nooshin A1 - Müller-Röber, Bernd A1 - Nikoloski, Zoran T1 - Segmentation of biological multivariate time-series data JF - Scientific reports N2 - Time-series data from multicomponent systems capture the dynamics of the ongoing processes and reflect the interactions between the components. The progression of processes in such systems usually involves check-points and events at which the relationships between the components are altered in response to stimuli. Detecting these events together with the implicated components can help understand the temporal aspects of complex biological systems. Here we propose a regularized regression-based approach for identifying breakpoints and corresponding segments from multivariate time-series data. In combination with techniques from clustering, the approach also allows estimating the significance of the determined breakpoints as well as the key components implicated in the emergence of the breakpoints. Comparative analysis with the existing alternatives demonstrates the power of the approach to identify biologically meaningful breakpoints in diverse time-resolved transcriptomics data sets from the yeast Saccharomyces cerevisiae and the diatom Thalassiosira pseudonana. Y1 - 2015 U6 - https://doi.org/10.1038/srep08937 SN - 2045-2322 VL - 5 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Lindauer, Marius A1 - Hoos, Holger H. A1 - Hutter, Frank A1 - Schaub, Torsten T1 - An automatically configured algorithm selector JF - The journal of artificial intelligence research N2 - Algorithm selection (AS) techniques - which involve choosing from a set of algorithms the one expected to solve a given problem instance most efficiently - have substantially improved the state of the art in solving many prominent AI problems, such as SAT, CSP, ASP, MAXSAT and QBF. Although several AS procedures have been introduced, not too surprisingly, none of them dominates all others across all AS scenarios. Furthermore, these procedures have parameters whose optimal values vary across AS scenarios. This holds specifically for the machine learning techniques that form the core of current AS procedures, and for their hyperparameters. Therefore, to successfully apply AS to new problems, algorithms and benchmark sets, two questions need to be answered: (i) how to select an AS approach and (ii) how to set its parameters effectively. We address both of these problems simultaneously by using automated algorithm configuration. Specifically, we demonstrate that we can automatically configure claspfolio 2, which implements a large variety of different AS approaches and their respective parameters in a single, highly-parameterized algorithm framework. Our approach, dubbed AutoFolio, allows researchers and practitioners across a broad range of applications to exploit the combined power of many different AS methods. We demonstrate AutoFolio can significantly improve the performance of claspfolio 2 on 8 out of the 13 scenarios from the Algorithm Selection Library, leads to new state-of-the-art algorithm selectors for 7 of these scenarios, and matches state-of-the-art performance (statistically) on all other scenarios. Compared to the best single algorithm for each AS scenario, AutoFolio achieves average speedup factors between 1.3 and 15.4. Y1 - 2015 SN - 1076-9757 SN - 1943-5037 VL - 53 SP - 745 EP - 778 PB - AI Access Foundation CY - Marina del Rey ER - TY - JOUR A1 - Videla, Santiago A1 - Guziolowski, Carito A1 - Eduati, Federica A1 - Thiele, Sven A1 - Gebser, Martin A1 - Nicolas, Jacques A1 - Saez-Rodriguez, Julio A1 - Schaub, Torsten A1 - Siegel, Anne T1 - Learning Boolean logic models of signaling networks with ASP JF - Theoretical computer science N2 - Boolean networks provide a simple yet powerful qualitative modeling approach in systems biology. However, manual identification of logic rules underlying the system being studied is in most cases out of reach. Therefore, automated inference of Boolean logical networks from experimental data is a fundamental question in this field. This paper addresses the problem consisting of learning from a prior knowledge network describing causal interactions and phosphorylation activities at a pseudo-steady state, Boolean logic models of immediate-early response in signaling transduction networks. The underlying optimization problem has been so far addressed through mathematical programming approaches and the use of dedicated genetic algorithms. In a recent work we have shown severe limitations of stochastic approaches in this domain and proposed to use Answer Set Programming (ASP), considering a simpler problem setting. Herein, we extend our previous work in order to consider more realistic biological conditions including numerical datasets, the presence of feedback-loops in the prior knowledge network and the necessity of multi-objective optimization. In order to cope with such extensions, we propose several discretization schemes and elaborate upon our previous ASP encoding. Towards real-world biological data, we evaluate the performance of our approach over in silico numerical datasets based on a real and large-scale prior knowledge network. The correctness of our encoding and discretization schemes are dealt with in Appendices A-B. (C) 2014 Elsevier B.V. All rights reserved. KW - Answer set programming KW - Signaling transduction networks KW - Boolean logic models KW - Combinatorial multi-objective optimization KW - Systems biology Y1 - 2015 U6 - https://doi.org/10.1016/j.tcs.2014.06.022 SN - 0304-3975 SN - 1879-2294 VL - 599 SP - 79 EP - 101 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hoos, Holger A1 - Kaminski, Roland A1 - Lindauer, Marius A1 - Schaub, Torsten T1 - aspeed: Solver scheduling via answer set programming JF - Theory and practice of logic programming N2 - Although Boolean Constraint Technology has made tremendous progress over the last decade, the efficacy of state-of-the-art solvers is known to vary considerably across different types of problem instances, and is known to depend strongly on algorithm parameters. This problem was addressed by means of a simple, yet effective approach using handmade, uniform, and unordered schedules of multiple solvers in ppfolio, which showed very impressive performance in the 2011 Satisfiability Testing (SAT) Competition. Inspired by this, we take advantage of the modeling and solving capacities of Answer Set Programming (ASP) to automatically determine more refined, that is, nonuniform and ordered solver schedules from the existing benchmarking data. We begin by formulating the determination of such schedules as multi-criteria optimization problems and provide corresponding ASP encodings. The resulting encodings are easily customizable for different settings, and the computation of optimum schedules can mostly be done in the blink of an eye, even when dealing with large runtime data sets stemming from many solvers on hundreds to thousands of instances. Also, the fact that our approach can be customized easily enabled us to swiftly adapt it to generate parallel schedules for multi-processor machines. KW - algorithm schedules KW - answer set programming KW - portfolio-based solving Y1 - 2015 U6 - https://doi.org/10.1017/S1471068414000015 SN - 1471-0684 SN - 1475-3081 VL - 15 SP - 117 EP - 142 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Kujath, Bertold T1 - Lernwirksamkeits- und Zielgruppenanalyse für ein Lehrvideo zum informatischen Problemlösen JF - Commentarii informaticae didacticae (CID) N2 - Aus einer Vergleichsstudie mit starken und schwachen Problemlösern konnten Erkenntnisse über die effizienten Herangehensweisen von Hochleistern an Informatikprobleme gewonnen werden. Diese Erkenntnisse wurden in einem Lehrvideo zum informatischen Problemlösen didaktisch aufgearbeitet, sodass Lernenden der Einsatz von Baumstrukturen und Rekursion im konkreten Kontext gezeigt werden kann. Nun wurde die tatsächliche Lernwirksamkeit des Videos sowie die Definition der Zielgruppe in einer Vergleichsstudie mit 66 Studienanfängern überprüft. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-94797 SN - 978-3-86956-376-3 SN - 1868-0844 SN - 2191-1940 IS - 10 SP - 25 EP - 39 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Böhne, Sebastian A1 - Kreitz, Christoph A1 - Knobelsdorf, Maria T1 - Mathematisches Argumentieren und Beweisen mit dem Theorembeweiser Coq JF - Commentarii informaticae didacticae (CID) N2 - Informatik-Studierende haben in der Mehrzahl Schwierigkeiten, einen Einstieg in die Theoretische Informatik zu finden und die Leistungsanforderungen in den Endklausuren der zugehörigen Lehrveranstaltungen zu erfüllen. Wir argumentieren, dass dieser Symptomatik mangelnde Kompetenzen im Umgang mit abstrakten und stark formalisierten Themeninhalten zugrunde liegen und schlagen vor, einen Beweisassistenten als interaktives Lernwerkzeug in der Eingangslehre der Theoretischen Informatik zu nutzen, um entsprechende Kompetenzen zu stärken. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-94824 SN - 978-3-86956-376-3 SN - 1868-0844 SN - 2191-1940 IS - 10 SP - 69 EP - 80 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Lagriffoul, Fabien A1 - Andres, Benjamin T1 - Combining task and motion planning BT - A culprit detection problem JF - The international journal of robotics research N2 - Solving problems combining task and motion planning requires searching across a symbolic search space and a geometric search space. Because of the semantic gap between symbolic and geometric representations, symbolic sequences of actions are not guaranteed to be geometrically feasible. This compels us to search in the combined search space, in which frequent backtracks between symbolic and geometric levels make the search inefficient.We address this problem by guiding symbolic search with rich information extracted from the geometric level through culprit detection mechanisms. KW - combined task and motion planning KW - manipulation planning Y1 - 2016 U6 - https://doi.org/10.1177/0278364915619022 SN - 1741-3176 SN - 0278-3649 VL - 35 IS - 8 SP - 890 EP - 927 PB - Sage Science Press CY - Thousand Oaks ER - TY - JOUR A1 - Baedke, Jan A1 - Schöttler, Tobias T1 - Visual Metaphors in the Sciences BT - the Case of Epigenetic Landscape Images JF - Journal for General Philosophy of Science N2 - Recent philosophical analyses of the epistemic dimension of images in the sciences show a certain trend in acknowledging potential roles of these images beyond their merely decorative or pedagogical functions. We argue, however, that this new debate has yet paid little attention to a special type of pictures, we call ‘visual metaphor’, and its versatile heuristic potential in organizing data, supporting communication, and guiding research, modeling, and theory formation. Based on a case study of Conrad Hal Waddington’s epigenetic landscape images in biology, we develop a descriptive framework applicable to heuristic roles of various visual metaphors in the sciences. KW - Conrad Hal Waddington KW - Epigenetic landscape KW - Modelling KW - Scientific images KW - Theory formation KW - Visual metaphor Y1 - 2017 U6 - https://doi.org/10.1007/s10838-016-9353-9 SN - 0925-4560 SN - 1572-8587 VL - 48 SP - 173 EP - 194 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Gebser, Martin A1 - Maratea, Marco A1 - Ricca, Francesco T1 - The sixth answer set programming competition JF - Journal of artificial intelligence research : JAIR N2 - Answer Set Programming (ASP) is a well-known paradigm of declarative programming with roots in logic programming and non-monotonic reasoning. Similar to other closely related problemsolving technologies, such as SAT/SMT, QBF, Planning and Scheduling, advancements in ASP solving are assessed in competition events. In this paper, we report about the design and results of the Sixth ASP Competition, which was jointly organized by the University of Calabria (Italy), Aalto University (Finland), and the University of Genoa (Italy), in affiliation with the 13th International Conference on Logic Programming and Non-Monotonic Reasoning. This edition maintained some of the design decisions introduced in 2014, e.g., the conception of sub-tracks, the scoring scheme,and the adherence to a fixed modeling language in order to push the adoption of the ASP-Core-2 standard. On the other hand, it featured also some novelties, like a benchmark selection stage classifying instances according to their empirical hardness, and a “Marathon” track where the topperforming systems are given more time for solving hard benchmarks. Y1 - 2017 U6 - https://doi.org/10.1613/jair.5373 SN - 1076-9757 SN - 1943-5037 VL - 60 SP - 41 EP - 95 PB - AI Access Found. CY - Marina del Rey ER - TY - JOUR A1 - Bailis, Peter A1 - Dillahunt, Tawanna A1 - Müller, Stefanie A1 - Baudisch, Patrick T1 - Research for Practice: Technology for Underserved Communities; Personal Fabrication JF - Communications of the ACM / Association for Computing Machinery N2 - THIS INSTALLMENT OF Research for Practice provides curated reading guides to technology for underserved communities and to new developments in personal fabrication. First, Tawanna Dillahunt describes design considerations and technology for underserved and impoverished communities. Designing for the more than 1.6 billion impoverished individuals worldwide requires special consideration of community needs, constraints, and context. Her selections span protocols for poor-quality communication networks, community-driven content generation, and resource and public service discovery. Second, Stefanie Mueller and Patrick Baudisch provide an overview of recent advances in personal fabrication (for example, 3D printers). Y1 - 2017 U6 - https://doi.org/10.1145/3080188 SN - 0001-0782 SN - 1557-7317 VL - 60 SP - 46 EP - 49 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Lindauer, Marius A1 - Hoos, Holger A1 - Leyton-Brown, Kevin A1 - Schaub, Torsten T1 - Automatic construction of parallel portfolios via algorithm configuration JF - Artificial intelligence N2 - Since 2004, increases in computational power described by Moore's law have substantially been realized in the form of additional cores rather than through faster clock speeds. To make effective use of modern hardware when solving hard computational problems, it is therefore necessary to employ parallel solution strategies. In this work, we demonstrate how effective parallel solvers for propositional satisfiability (SAT), one of the most widely studied NP-complete problems, can be produced automatically from any existing sequential, highly parametric SAT solver. Our Automatic Construction of Parallel Portfolios (ACPP) approach uses an automatic algorithm configuration procedure to identify a set of configurations that perform well when executed in parallel. Applied to two prominent SAT solvers, Lingeling and clasp, our ACPP procedure identified 8-core solvers that significantly outperformed their sequential counterparts on a diverse set of instances from the application and hard combinatorial category of the 2012 SAT Challenge. We further extended our ACPP approach to produce parallel portfolio solvers consisting of several different solvers by combining their configuration spaces. Applied to the component solvers of the 2012 SAT Challenge gold medal winning SAT Solver pfolioUZK, our ACPP procedures produced a significantly better-performing parallel SAT solver. KW - Algorithm configuration KW - Parallel SAT solving KW - Algorithm portfolios KW - Programming by optimization KW - Automated parallelization Y1 - 2016 U6 - https://doi.org/10.1016/j.artint.2016.05.004 SN - 0004-3702 SN - 1872-7921 VL - 244 SP - 272 EP - 290 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Baier, Thomas A1 - Di Ciccio, Claudio A1 - Mendling, Jan A1 - Weske, Mathias T1 - Matching events and activities by integrating behavioral aspects and label analysis JF - Software and systems modeling N2 - Nowadays, business processes are increasingly supported by IT services that produce massive amounts of event data during the execution of a process. These event data can be used to analyze the process using process mining techniques to discover the real process, measure conformance to a given process model, or to enhance existing models with performance information. Mapping the produced events to activities of a given process model is essential for conformance checking, annotation and understanding of process mining results. In order to accomplish this mapping with low manual effort, we developed a semi-automatic approach that maps events to activities using insights from behavioral analysis and label analysis. The approach extracts Declare constraints from both the log and the model to build matching constraints to efficiently reduce the number of possible mappings. These mappings are further reduced using techniques from natural language processing, which allow for a matching based on labels and external knowledge sources. The evaluation with synthetic and real-life data demonstrates the effectiveness of the approach and its robustness toward non-conforming execution logs. KW - Process mining KW - Event mapping KW - Business process intelligence KW - Constraint satisfaction KW - Declare KW - Natural language processing Y1 - 2018 U6 - https://doi.org/10.1007/s10270-017-0603-z SN - 1619-1366 SN - 1619-1374 VL - 17 IS - 2 SP - 573 EP - 598 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Przybylla, Mareen A1 - Romeike, Ralf T1 - Empowering learners with tools in CS education BT - physical computing in secondary schools JF - it - Information Technology N2 - In computer science, computer systems are both, objects of investigation and tools that enable creative learning and design. Tools for learning have a long tradition in computer science education. Already in the late 1960s, Papert developed a concept which had an immense impact on the development of informal education in the following years: his theory of constructionism understands learning as a creative process of knowledge construction that is most effective when learners create something purposeful that they can try out, show around, discuss, analyse and receive praise for. By now, there are numerous learning and programming environments that are based on the constructionist ideas. Modern tools offer opportunities for students to learn in motivating ways and gain impressive results in programming games, animations, implementing 3D models or developing interactive objects. This article gives an overview of computer science education research related to tools and media to be used in educational settings. We analyse different types of tools with a special focus on the categorization and development of tools for student adequate physical computing activities in the classroom. Research around the development and evaluation of tools and learning resources in the domain of physical computing is illustrated with the example of "My Interactive Garden", a constructionist learning and programming environment. It is explained how the results from empirical studies are integrated in the continuous development of the learning material. KW - tools KW - media KW - resources KW - computer science education KW - physical computing Y1 - 2018 U6 - https://doi.org/10.1515/itit-2017-0032 SN - 1611-2776 SN - 2196-7032 VL - 60 IS - 2 SP - 91 EP - 101 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Prescher, Denise A1 - Bornschein, Jens A1 - Köhlmann, Wiebke A1 - Weber, Gerhard T1 - Touching graphical applications BT - bimanual tactile interaction on the HyperBraille pin-matrix display JF - Universal Access in the Information Society N2 - Novel two-dimensional tactile displays enable blind users to not only get access to the textual but also to the graphical content of a graphical user interface. Due to the higher amount of information that can be presented in parallel, orientation and exploration can be more complex. In this paper we present the HyperBraille system, which consists of a pin-matrix device as well as a graphical screen reader providing the user with appropriate presentation and interaction possibilities. To allow for a detailed analysis of bimanual interaction strategies on a pin-matrix device, we conducted two user studies with a total of 12 blind people. The task was to fill in .pdf forms on the pin-matrix device by using different input methods, namely gestures, built-in hardware buttons as well as a conventional PC keyboard. The forms were presented in a semigraphic view type that not only contains Braille but also tactile widgets in a spatial arrangement. While completion time and error rate partly depended on the chosen input method, the usage of special reading strategies seemed to be independent of it. A direct comparison of the system and a conventional assistive technology (screen reader with single-line Braille device) showed that interaction on the pin-matrix device can be very efficient if the user is trained. The two-dimensional output can improve access to .pdf forms with insufficient accessibility as the mapping of input controls and the corresponding labels can be supported by a spatial presentation. KW - Planar tactile display KW - Blind users KW - pdf forms KW - Screen reader KW - Gesture input KW - Key input Y1 - 2018 U6 - https://doi.org/10.1007/s10209-017-0538-8 SN - 1615-5289 SN - 1615-5297 VL - 17 IS - 2 SP - 391 EP - 409 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Afantenos, Stergos A1 - Peldszus, Andreas A1 - Stede, Manfred T1 - Comparing decoding mechanisms for parsing argumentative structures JF - Argument & Computation N2 - Parsing of argumentative structures has become a very active line of research in recent years. Like discourse parsing or any other natural language task that requires prediction of linguistic structures, most approaches choose to learn a local model and then perform global decoding over the local probability distributions, often imposing constraints that are specific to the task at hand. Specifically for argumentation parsing, two decoding approaches have been recently proposed: Minimum Spanning Trees (MST) and Integer Linear Programming (ILP), following similar trends in discourse parsing. In contrast to discourse parsing though, where trees are not always used as underlying annotation schemes, argumentation structures so far have always been represented with trees. Using the ‘argumentative microtext corpus’ [in: Argumentation and Reasoned Action: Proceedings of the 1st European Conference on Argumentation, Lisbon 2015 / Vol. 2, College Publications, London, 2016, pp. 801–815] as underlying data and replicating three different decoding mechanisms, in this paper we propose a novel ILP decoder and an extension to our earlier MST work, and then thoroughly compare the approaches. The result is that our new decoder outperforms related work in important respects, and that in general, ILP and MST yield very similar performance. KW - Argumentation structure KW - argument mining KW - parsing Y1 - 2018 U6 - https://doi.org/10.3233/AAC-180033 SN - 1946-2166 SN - 1946-2174 VL - 9 IS - 3 SP - 177 EP - 192 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Giannini, Paola A1 - Richter, Tim A1 - Servetto, Marco A1 - Zucca, Elena T1 - Tracing sharing in an imperative pure calculus JF - Science of computer programming N2 - We introduce a type and effect system, for an imperative object calculus, which infers sharing possibly introduced by the evaluation of an expression, represented as an equivalence relation among its free variables. This direct representation of sharing effects at the syntactic level allows us to express in a natural way, and to generalize, widely-used notions in literature, notably uniqueness and borrowing. Moreover, the calculus is pure in the sense that reduction is defined on language terms only, since they directly encode store. The advantage of this non-standard execution model with respect to a behaviorally equivalent standard model using a global auxiliary structure is that reachability relations among references are partly encoded by scoping. (C) 2018 Elsevier B.V. All rights reserved. KW - Imperative calculi KW - Sharing KW - Type and effect systems Y1 - 2018 U6 - https://doi.org/10.1016/j.scico.2018.11.007 SN - 0167-6423 SN - 1872-7964 VL - 172 SP - 180 EP - 202 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bordihn, Henning A1 - Mitrana, Victor A1 - Negru, Maria C. A1 - Paun, Andrei A1 - Paun, Mihaela T1 - Small networks of polarized splicing processors are universal JF - Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal N2 - In this paper, we consider the computational power of a new variant of networks of splicing processors in which each processor as well as the data navigating throughout the network are now considered to be polarized. While the polarization of every processor is predefined (negative, neutral, positive), the polarization of data is dynamically computed by means of a valuation mapping. Consequently, the protocol of communication is naturally defined by means of this polarization. We show that networks of polarized splicing processors (NPSP) of size 2 are computationally complete, which immediately settles the question of designing computationally complete NPSPs of minimal size. With two more nodes we can simulate every nondeterministic Turing machine without increasing the time complexity. Particularly, we prove that NPSP of size 4 can accept all languages in NP in polynomial time. Furthermore, another computational model that is universal, namely the 2-tag system, can be simulated by NPSP of size 3 preserving the time complexity. All these results can be obtained with NPSPs with valuations in the set as well. We finally show that Turing machines can simulate a variant of NPSPs and discuss the time complexity of this simulation. KW - Computing with DNA KW - Splicing KW - Splicing processor KW - Polarization KW - 2-tag system KW - Turing machine Y1 - 2018 U6 - https://doi.org/10.1007/s11047-018-9691-0 SN - 1567-7818 SN - 1572-9796 VL - 17 IS - 4 SP - 799 EP - 809 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Tscherejkina, Anna A1 - Morgiel, Anna A1 - Moebert, Tobias T1 - Computergestütztes Training von sozio-emotionalen Kompetenzen durch Minispiele JF - E-Learning Symposium 2018 N2 - Das Training sozioemotionaler Kompetenzen ist gerade für Menschen mit Autismus nützlich. Ein solches Training kann mithilfe einer spielbasierten Anwendung effektiv gestaltet werden. Zwei Minispiele, Mimikry und Emo-Mahjong, wurden realisiert und hinsichtlich User Experience evaluiert. Die jeweiligen Konzepte und die Evaluationsergebnisse sollen hier vorgestellt werden. KW - Computergestützes Training KW - User Experience KW - Digital Game Based Learning KW - Autismus Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-421937 SP - 41 EP - 52 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Kiy, Alexander T1 - Digitale Medien & Hochschul-Cloud: Eine vielversprechende Verbindung JF - eleed N2 - Ob Online-Kurse, videobasierte Lehrangebote, mobile Applikationen, eigenentwickelte oder kommerzielle Web 2.0-Anwendungen, die Fülle digitaler Unterstützungsangebote ist kaum zu überblicken. Dabei bieten mobile Endgeräte, Web-Anwendungen und Apps Chancen Lehre, Studium und Forschung maßgeblich neu zu gestalten. Im Beitrag wird ein Beschreibungsrahmen für die mediendidaktische Ausgestaltung von Lehr-, Lern- und Forschungsarrangements vorgestellt, der die technischen Gesichtspunkte hervorhebt. Anschließend werden unterschiedliche Nutzungsszenarien unter Einbeziehung digitaler Medien skizziert. Diese werden als Ausgangspunkt genommen um das Konzept einer Systemarchitektur vorzustellen, die es zum einen ermöglicht beliebige Applikationen automatisiert bereit zu stellen und zum anderen die anfallenden Nutzendendaten plattformübergreifend zu aggregieren und für eine Ausgestaltung virtueller Lehr- und Lernräumen zu nutzen. KW - e-learning KW - Digitale Medien KW - Berliner Modell KW - TPACK KW - Hochschullehre KW - Hochschul-Cloud KW - xAPI KW - SaaSAbstract Y1 - 2018 UR - https://eleed.campussource.de/archive/se2018/4659 IS - 12 ER - TY - JOUR A1 - Li, Yuanqing A1 - Chen, Li A1 - Nofal, Issam A1 - Chen, Mo A1 - Wang, Haibin A1 - Liu, Rui A1 - Chen, Qingyu A1 - Krstić, Miloš A1 - Shi, Shuting A1 - Guo, Gang A1 - Baeg, Sang H. A1 - Wen, Shi-Jie A1 - Wong, Richard T1 - Modeling and analysis of single-event transient sensitivity of a 65 nm clock tree JF - Microelectronics reliability N2 - The soft error rate (SER) due to heavy-ion irradiation of a clock tree is investigated in this paper. A method for clock tree SER prediction is developed, which employs a dedicated soft error analysis tool to characterize the single-event transient (SET) sensitivities of clock inverters and other commercial tools to calculate the SER through fault-injection simulations. A test circuit including a flip-flop chain and clock tree in a 65 nm CMOS technology is developed through the automatic ASIC design flow. This circuit is analyzed with the developed method to calculate its clock tree SER. In addition, this circuit is implemented in a 65 nm test chip and irradiated by heavy ions to measure its SER resulting from the SETs in the clock tree. The experimental and calculation results of this case study present good correlation, which verifies the effectiveness of the developed method. KW - Clock tree KW - Modeling KW - Single-event transient (SET) Y1 - 2018 U6 - https://doi.org/10.1016/j.microrel.2018.05.016 SN - 0026-2714 VL - 87 SP - 24 EP - 32 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Brewka, Gerhard A1 - Ellmauthaler, Stefan A1 - Kern-Isberner, Gabriele A1 - Obermeier, Philipp A1 - Ostrowski, Max A1 - Romero, Javier A1 - Schaub, Torsten A1 - Schieweck, Steffen T1 - Advanced solving technology for dynamic and reactive applications JF - Künstliche Intelligenz Y1 - 2018 U6 - https://doi.org/10.1007/s13218-018-0538-8 SN - 0933-1875 SN - 1610-1987 VL - 32 IS - 2-3 SP - 199 EP - 200 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Schaub, Torsten A1 - Woltran, Stefan T1 - Answer set programming unleashed! JF - Künstliche Intelligenz N2 - Answer Set Programming faces an increasing popularity for problem solving in various domains. While its modeling language allows us to express many complex problems in an easy way, its solving technology enables their effective resolution. In what follows, we detail some of the key factors of its success. Answer Set Programming [ASP; Brewka et al. Commun ACM 54(12):92–103, (2011)] is seeing a rapid proliferation in academia and industry due to its easy and flexible way to model and solve knowledge-intense combinatorial (optimization) problems. To this end, ASP offers a high-level modeling language paired with high-performance solving technology. As a result, ASP systems provide out-off-the-box, general-purpose search engines that allow for enumerating (optimal) solutions. They are represented as answer sets, each being a set of atoms representing a solution. The declarative approach of ASP allows a user to concentrate on a problem’s specification rather than the computational means to solve it. This makes ASP a prime candidate for rapid prototyping and an attractive tool for teaching key AI techniques since complex problems can be expressed in a succinct and elaboration tolerant way. This is eased by the tuning of ASP’s modeling language to knowledge representation and reasoning (KRR). The resulting impact is nicely reflected by a growing range of successful applications of ASP [Erdem et al. AI Mag 37(3):53–68, 2016; Falkner et al. Industrial applications of answer set programming. K++nstliche Intelligenz (2018)] Y1 - 2018 U6 - https://doi.org/10.1007/s13218-018-0550-z SN - 0933-1875 SN - 1610-1987 VL - 32 IS - 2-3 SP - 105 EP - 108 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Gebser, Martin A1 - Obermeier, Philipp A1 - Schaub, Torsten A1 - Ratsch-Heitmann, Michel A1 - Runge, Mario T1 - Routing driverless transport vehicles in car assembly with answer set programming JF - Theory and practice of logic programming N2 - Automated storage and retrieval systems are principal components of modern production and warehouse facilities. In particular, automated guided vehicles nowadays substitute human-operated pallet trucks in transporting production materials between storage locations and assembly stations. While low-level control systems take care of navigating such driverless vehicles along programmed routes and avoid collisions even under unforeseen circumstances, in the common case of multiple vehicles sharing the same operation area, the problem remains how to set up routes such that a collection of transport tasks is accomplished most effectively. We address this prevalent problem in the context of car assembly at Mercedes-Benz Ludwigsfelde GmbH, a large-scale producer of commercial vehicles, where routes for automated guided vehicles used in the production process have traditionally been hand-coded by human engineers. Such adhoc methods may suffice as long as a running production process remains in place, while any change in the factory layout or production targets necessitates tedious manual reconfiguration, not to mention the missing portability between different production plants. Unlike this, we propose a declarative approach based on Answer Set Programming to optimize the routes taken by automated guided vehicles for accomplishing transport tasks. The advantages include a transparent and executable problem formalization, provable optimality of routes relative to objective criteria, as well as elaboration tolerance towards particular factory layouts and production targets. Moreover, we demonstrate that our approach is efficient enough to deal with the transport tasks evolving in realistic production processes at the car factory of Mercedes-Benz Ludwigsfelde GmbH. KW - automated guided vehicle routing KW - car assembly operations KW - answer set programming Y1 - 2018 U6 - https://doi.org/10.1017/S1471068418000182 SN - 1471-0684 SN - 1475-3081 VL - 18 IS - 3-4 SP - 520 EP - 534 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Banbara, Mutsunori A1 - Inoue, Katsumi A1 - Kaufmann, Benjamin A1 - Okimoto, Tenda A1 - Schaub, Torsten A1 - Soh, Takehide A1 - Tamura, Naoyuki A1 - Wanko, Philipp T1 - teaspoon BT - solving the curriculum-based course timetabling problems with answer set programming JF - Annals of operation research N2 - Answer Set Programming (ASP) is an approach to declarative problem solving, combining a rich yet simple modeling language with high performance solving capacities. We here develop an ASP-based approach to curriculum-based course timetabling (CB-CTT), one of the most widely studied course timetabling problems. The resulting teaspoon system reads a CB-CTT instance of a standard input format and converts it into a set of ASP facts. In turn, these facts are combined with a first-order encoding for CB-CTT solving, which can subsequently be solved by any off-the-shelf ASP systems. We establish the competitiveness of our approach by empirically contrasting it to the best known bounds obtained so far via dedicated implementations. Furthermore, we extend the teaspoon system to multi-objective course timetabling and consider minimal perturbation problems. KW - Educational timetabling KW - Course timetabling KW - Answer set programming KW - Multi-objective optimization KW - Minimal perturbation problems Y1 - 2018 U6 - https://doi.org/10.1007/s10479-018-2757-7 SN - 0254-5330 SN - 1572-9338 VL - 275 IS - 1 SP - 3 EP - 37 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Gebser, Martin A1 - Kaminski, Roland A1 - Kaufmann, Benjamin A1 - Lühne, Patrick A1 - Obermeier, Philipp A1 - Ostrowski, Max A1 - Romero Davila, Javier A1 - Schaub, Torsten A1 - Schellhorn, Sebastian A1 - Wanko, Philipp T1 - The Potsdam Answer Set Solving Collection 5.0 JF - Künstliche Intelligenz N2 - The Potsdam answer set solving collection, or Potassco for short, bundles various tools implementing and/or applying answer set programming. The article at hand succeeds an earlier description of the Potassco project published in Gebser et al. (AI Commun 24(2):107-124, 2011). Hence, we concentrate in what follows on the major features of the most recent, fifth generation of the ASP system clingo and highlight some recent resulting application systems. Y1 - 2018 U6 - https://doi.org/10.1007/s13218-018-0528-x SN - 0933-1875 SN - 1610-1987 VL - 32 IS - 2-3 SP - 181 EP - 182 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Haubelt, Christian A1 - Neubauer, Kai A1 - Schaub, Torsten A1 - Wanko, Philipp T1 - Design space exploration with answer set programming JF - Künstliche Intelligenz N2 - The aim of our project design space exploration with answer set programming is to develop a general framework based on Answer Set Programming (ASP) that finds valid solutions to the system design problem and simultaneously performs Design Space Exploration (DSE) to find the most favorable alternatives. We leverage recent developments in ASP solving that allow for tight integration of background theories to create a holistic framework for effective DSE. Y1 - 2018 U6 - https://doi.org/10.1007/s13218-018-0530-3 SN - 0933-1875 SN - 1610-1987 VL - 32 IS - 2-3 SP - 205 EP - 206 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Prasse, Paul A1 - Knaebel, Rene A1 - Machlica, Lukas A1 - Pevny, Tomas A1 - Scheffer, Tobias T1 - Joint detection of malicious domains and infected clients JF - Machine learning N2 - Detection of malware-infected computers and detection of malicious web domains based on their encrypted HTTPS traffic are challenging problems, because only addresses, timestamps, and data volumes are observable. The detection problems are coupled, because infected clients tend to interact with malicious domains. Traffic data can be collected at a large scale, and antivirus tools can be used to identify infected clients in retrospect. Domains, by contrast, have to be labeled individually after forensic analysis. We explore transfer learning based on sluice networks; this allows the detection models to bootstrap each other. In a large-scale experimental study, we find that the model outperforms known reference models and detects previously unknown malware, previously unknown malware families, and previously unknown malicious domains. KW - Machine learning KW - Neural networks KW - Computer security KW - Traffic data KW - Https traffic Y1 - 2019 U6 - https://doi.org/10.1007/s10994-019-05789-z SN - 0885-6125 SN - 1573-0565 VL - 108 IS - 8-9 SP - 1353 EP - 1368 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Metref, Sammy A1 - Cosme, Emmanuel A1 - Le Sommer, Julien A1 - Poel, Nora A1 - Brankart, Jean-Michel A1 - Verron, Jacques A1 - Gomez Navarro, Laura T1 - Reduction of spatially structured errors in Wide-Swath altimetric satellite data using data assimilation JF - Remote sensing N2 - The Surface Water and Ocean Topography (SWOT) mission is a next generation satellite mission expected to provide a 2 km-resolution observation of the sea surface height (SSH) on a two-dimensional swath. Processing SWOT data will be challenging because of the large amount of data, the mismatch between a high spatial resolution and a low temporal resolution, and the observation errors. The present paper focuses on the reduction of the spatially structured errors of SWOT SSH data. It investigates a new error reduction method and assesses its performance in an observing system simulation experiment. The proposed error-reduction method first projects the SWOT SSH onto a subspace spanned by the SWOT spatially structured errors. This projection is removed from the SWOT SSH to obtain a detrended SSH. The detrended SSH is then processed within an ensemble data assimilation analysis to retrieve a full SSH field. In the latter step, the detrending is applied to both the SWOT data and an ensemble of model-simulated SSH fields. Numerical experiments are performed with synthetic SWOT observations and an ensemble from a North Atlantic, 1/60 degrees simulation of the ocean circulation (NATL60). The data assimilation analysis is carried out with an ensemble Kalman filter. The results are assessed with root mean square errors, power spectrum density, and spatial coherence. They show that a significant part of the large scale SWOT errors is reduced. The filter analysis also reduces the small scale errors and allows for an accurate recovery of the energy of the signal down to 25 km scales. In addition, using the SWOT nadir data to adjust the SSH detrending further reduces the errors. KW - SWOT KW - correlated errors KW - OSSE KW - projection KW - detrending KW - ensemble kalman filter Y1 - 2019 U6 - https://doi.org/10.3390/rs11111336 SN - 2072-4292 VL - 11 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Pousttchi, Key A1 - Gleiß, Alexander T1 - Surrounded by middlemen - how multi-sided platforms change the insurance industry JF - Electron Markets N2 - Multi-sided platforms (MSP) strongly affect markets and play a crucial part within the digital and networked economy. Although empirical evidence indicates their occurrence in many industries, research has not investigated the game-changing impact of MSP on traditional markets to a sufficient extent. More specifically, we have little knowledge of how MSP affect value creation and customer interaction in entire markets, exploiting the potential of digital technologies to offer new value propositions. Our paper addresses this research gap and provides an initial systematic approach to analyze the impact of MSP on the insurance industry. For this purpose, we analyze the state of the art in research and practice in order to develop a reference model of the value network for the insurance industry. On this basis, we conduct a case-study analysis to discover and analyze roles which are occupied or even newly created by MSP. As a final step, we categorize MSP with regard to their relation to traditional insurance companies, resulting in a classification scheme with four MSP standard types: Competition, Coordination, Cooperation, Collaboration. KW - Multi-sided platforms KW - Insurance industry KW - Value network KW - Digitalization KW - Customer ownership Y1 - 2019 U6 - https://doi.org/10.1007/s12525-019-00363-w SN - 1019-6781 SN - 1422-8890 VL - 29 IS - 4 SP - 609 EP - 629 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Waitelonis, Jörg A1 - Jürges, Henrik A1 - Sack, Harald T1 - Remixing entity linking evaluation datasets for focused benchmarking JF - Semantic Web N2 - In recent years, named entity linking (NEL) tools were primarily developed in terms of a general approach, whereas today numerous tools are focusing on specific domains such as e.g. the mapping of persons and organizations only, or the annotation of locations or events in microposts. However, the available benchmark datasets necessary for the evaluation of NEL tools do not reflect this focalizing trend. We have analyzed the evaluation process applied in the NEL benchmarking framework GERBIL [in: Proceedings of the 24th International Conference on World Wide Web (WWW’15), International World Wide Web Conferences Steering Committee, Republic and Canton of Geneva, Switzerland, 2015, pp. 1133–1143, Semantic Web 9(5) (2018), 605–625] and all its benchmark datasets. Based on these insights we have extended the GERBIL framework to enable a more fine grained evaluation and in depth analysis of the available benchmark datasets with respect to different emphases. This paper presents the implementation of an adaptive filter for arbitrary entities and customized benchmark creation as well as the automated determination of typical NEL benchmark dataset properties, such as the extent of content-related ambiguity and diversity. These properties are integrated on different levels, which also enables to tailor customized new datasets out of the existing ones by remixing documents based on desired emphases. Besides a new system library to enrich provided NIF [in: International Semantic Web Conference (ISWC’13), Lecture Notes in Computer Science, Vol. 8219, Springer, Berlin, Heidelberg, 2013, pp. 98–113] datasets with statistical information, best practices for dataset remixing are presented, and an in depth analysis of the performance of entity linking systems on special focus datasets is presented. KW - Entity Linking KW - GERBIL KW - evaluation KW - benchmark Y1 - 2019 U6 - https://doi.org/10.3233/SW-180334 SN - 1570-0844 SN - 2210-4968 VL - 10 IS - 2 SP - 385 EP - 412 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Strickroth, Sven T1 - PLATON BT - Developing a Graphical Lesson Planning System for Prospective Teachers JF - Education Sciences N2 - Lesson planning is both an important and demanding task—especially as part of teacher training. This paper presents the requirements for a lesson planning system and evaluates existing systems regarding these requirements. One major drawback of existing software tools is that most are limited to a text- or form-based representation of the lesson designs. In this article, a new approach with a graphical, time-based representation with (automatic) analyses methods is proposed and the system architecture and domain model are described in detail. The approach is implemented in an interactive, web-based prototype called PLATON, which additionally supports the management of lessons in units as well as the modelling of teacher and student-generated resources. The prototype was evaluated in a study with 61 prospective teachers (bachelor’s and master’s preservice teachers as well as teacher trainees in post-university teacher training) in Berlin, Germany, with a focus on usability. The results show that this approach proofed usable for lesson planning and offers positive effects for the perception of time and self-reflection. KW - lesson planning KW - lesson preparation KW - support system KW - automatic feedback Y1 - 2019 U6 - https://doi.org/10.3390/educsci9040254 SN - 2227-7102 VL - 9 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Cabalar, Pedro A1 - Fandiño, Jorge A1 - Schaub, Torsten A1 - Schellhorn, Sebastian T1 - Gelfond-Zhang aggregates as propositional formulas JF - Artificial intelligence N2 - Answer Set Programming (ASP) has become a popular and widespread paradigm for practical Knowledge Representation thanks to its expressiveness and the available enhancements of its input language. One of such enhancements is the use of aggregates, for which different semantic proposals have been made. In this paper, we show that any ASP aggregate interpreted under Gelfond and Zhang's (GZ) semantics can be replaced (under strong equivalence) by a propositional formula. Restricted to the original GZ syntax, the resulting formula is reducible to a disjunction of conjunctions of literals but the formulation is still applicable even when the syntax is extended to allow for arbitrary formulas (including nested aggregates) in the condition. Once GZ-aggregates are represented as formulas, we establish a formal comparison (in terms of the logic of Here-and-There) to Ferraris' (F) aggregates, which are defined by a different formula translation involving nested implications. In particular, we prove that if we replace an F-aggregate by a GZ-aggregate in a rule head, we do not lose answer sets (although more can be gained). This extends the previously known result that the opposite happens in rule bodies, i.e., replacing a GZ-aggregate by an F-aggregate in the body may yield more answer sets. Finally, we characterize a class of aggregates for which GZ- and F-semantics coincide. KW - Aggregates KW - Answer Set Programming Y1 - 2019 U6 - https://doi.org/10.1016/j.artint.2018.10.007 SN - 0004-3702 SN - 1872-7921 VL - 274 SP - 26 EP - 43 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Aguado, Felicidad A1 - Cabalar, Pedro A1 - Fandiño, Jorge A1 - Pearce, David A1 - Perez, Gilberto A1 - Vidal, Concepcion T1 - Forgetting auxiliary atoms in forks JF - Artificial intelligence N2 - In this work we tackle the problem of checking strong equivalence of logic programs that may contain local auxiliary atoms, to be removed from their stable models and to be forbidden in any external context. We call this property projective strong equivalence (PSE). It has been recently proved that not any logic program containing auxiliary atoms can be reformulated, under PSE, as another logic program or formula without them – this is known as strongly persistent forgetting. In this paper, we introduce a conservative extension of Equilibrium Logic and its monotonic basis, the logic of Here-and-There, in which we deal with a new connective ‘|’ we call fork. We provide a semantic characterisation of PSE for forks and use it to show that, in this extension, it is always possible to forget auxiliary atoms under strong persistence. We further define when the obtained fork is representable as a regular formula. KW - Answer set programming KW - Non-monotonic reasoning KW - Equilibrium logic KW - Denotational semantics KW - Forgetting KW - Strong equivalence Y1 - 2019 U6 - https://doi.org/10.1016/j.artint.2019.07.005 SN - 0004-3702 SN - 1872-7921 VL - 275 SP - 575 EP - 601 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Aguado, Felicidad A1 - Cabalar, Pedro A1 - Fandiño, Jorge A1 - Pearce, David A1 - Perez, Gilberto A1 - Vidal-Peracho, Concepcion T1 - Revisiting Explicit Negation in Answer Set Programming JF - Theory and practice of logic programming KW - Answer set programming KW - Non-monotonic reasoning KW - Equilibrium logic KW - Explicit negation Y1 - 2019 U6 - https://doi.org/10.1017/S1471068419000267 SN - 1471-0684 SN - 1475-3081 VL - 19 IS - 5-6 SP - 908 EP - 924 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Dimopoulos, Yannis A1 - Gebser, Martin A1 - Lühne, Patrick A1 - Romero Davila, Javier A1 - Schaub, Torsten T1 - plasp 3 BT - Towards Effective ASP Planning JF - Theory and practice of logic programming N2 - We describe the new version of the Planning Domain Definition Language (PDDL)-to-Answer Set Programming (ASP) translator plasp. First, it widens the range of accepted PDDL features. Second, it contains novel planning encodings, some inspired by Satisfiability Testing (SAT) planning and others exploiting ASP features such as well-foundedness. All of them are designed for handling multivalued fluents in order to capture both PDDL as well as SAS planning formats. Third, enabled by multishot ASP solving, it offers advanced planning algorithms also borrowed from SAT planning. As a result, plasp provides us with an ASP-based framework for studying a variety of planning techniques in a uniform setting. Finally, we demonstrate in an empirical analysis that these techniques have a significant impact on the performance of ASP planning. KW - knowledge representation and nonmonotonic reasoning KW - technical notes and rapid communications KW - answer set programming KW - automated planning KW - action and change Y1 - 2019 U6 - https://doi.org/10.1017/S1471068418000583 SN - 1471-0684 SN - 1475-3081 VL - 19 IS - 3 SP - 477 EP - 504 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Frioux, Clémence A1 - Schaub, Torsten A1 - Schellhorn, Sebastian A1 - Siegel, Anne A1 - Wanko, Philipp T1 - Hybrid metabolic network completion JF - Theory and practice of logic programming N2 - Metabolic networks play a crucial role in biology since they capture all chemical reactions in an organism. While there are networks of high quality for many model organisms, networks for less studied organisms are often of poor quality and suffer from incompleteness. To this end, we introduced in previous work an answer set programming (ASP)-based approach to metabolic network completion. Although this qualitative approach allows for restoring moderately degraded networks, it fails to restore highly degraded ones. This is because it ignores quantitative constraints capturing reaction rates. To address this problem, we propose a hybrid approach to metabolic network completion that integrates our qualitative ASP approach with quantitative means for capturing reaction rates. We begin by formally reconciling existing stoichiometric and topological approaches to network completion in a unified formalism. With it, we develop a hybrid ASP encoding and rely upon the theory reasoning capacities of the ASP system dingo for solving the resulting logic program with linear constraints over reals. We empirically evaluate our approach by means of the metabolic network of Escherichia coli. Our analysis shows that our novel approach yields greatly superior results than obtainable from purely qualitative or quantitative approaches. KW - answer set programming KW - metabolic network KW - gap-filling KW - linear programming KW - hybrid solving KW - bioinformatics Y1 - 2018 U6 - https://doi.org/10.1017/S1471068418000455 SN - 1471-0684 SN - 1475-3081 VL - 19 IS - 1 SP - 83 EP - 108 PB - Cambridge University Press CY - New York ER -