@incollection{KiyGessnerLuckeetal.2015, author = {Kiy, Alexander and Geßner, Hendrik and Lucke, Ulrike and Gr{\"u}newald, Franka}, title = {A Hybrid and Modular Framework for Mobile Campus Applications}, series = {i-com}, volume = {2015}, booktitle = {i-com}, number = {14}, publisher = {de Gruyter}, address = {Berlin}, issn = {2196-6826}, doi = {10.1515/icom-2015-0016}, publisher = {Universit{\"a}t Potsdam}, pages = {63 -- 73}, year = {2015}, abstract = {Mobile devices and associated applications (apps) are an indispensable part of daily life and provide access to important information anytime and anywhere. However, the availability of university-wide services in the mobile sector is still poor. If they exist they usually result from individual activities of students and teachers. Mobile applications can have an essential impact on the improvement of students' self-organization as well as on the design and enhancement of specific learning scenarios, though. This article introduces a mobile campus app framework, which integrates central campus services and decentralized learning applications. An analysis of strengths and weaknesses of different approaches is presented to summarize and evaluate them in terms of requirements, development, maintenance and operation. The article discusses the underlying service-oriented architecture that allows transferring the campus app to other universities or institutions at reasonable cost. It concludes with a presentation of the results as well as ongoing discussions and future work}, language = {en} } @article{LiangLiuLiuetal.2015, author = {Liang, Feng and Liu, Yunzhen and Liu, Hai and Ma, Shilong and Schnor, Bettina}, title = {A Parallel Job Execution Time Estimation Approach Based on User Submission Patterns within Computational Grids}, series = {International journal of parallel programming}, volume = {43}, journal = {International journal of parallel programming}, number = {3}, publisher = {Springer}, address = {New York}, issn = {0885-7458}, doi = {10.1007/s10766-013-0294-1}, pages = {440 -- 454}, year = {2015}, abstract = {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 \%.}, language = {en} } @article{PabloAlarconArroyoBordihnetal.2015, author = {Pablo Alarcon, Pedro and Arroyo, Fernando and Bordihn, Henning and Mitrana, Victor and Mueller, Mike}, title = {Ambiguity of the multiple interpretations on regular languages}, series = {Fundamenta informaticae}, volume = {138}, journal = {Fundamenta informaticae}, number = {1-2}, publisher = {IOS Press}, address = {Amsterdam}, issn = {0169-2968}, doi = {10.3233/FI-2015-1200}, pages = {85 -- 95}, year = {2015}, abstract = {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.}, language = {en} } @article{LindauerHoosHutteretal.2015, author = {Lindauer, Marius and Hoos, Holger H. and Hutter, Frank and Schaub, Torsten H.}, title = {An automatically configured algorithm selector}, series = {The journal of artificial intelligence research}, volume = {53}, journal = {The journal of artificial intelligence research}, publisher = {AI Access Foundation}, address = {Marina del Rey}, issn = {1076-9757}, pages = {745 -- 778}, year = {2015}, abstract = {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.}, language = {en} } @phdthesis{Heinze2015, author = {Heinze, Theodor}, title = {Analyse von Patientendaten und Entscheidungsunterst{\"u}tzung in der Telemedizin}, school = {Universit{\"a}t Potsdam}, pages = {173}, year = {2015}, language = {de} } @article{HoosKaminskiLindaueretal.2015, author = {Hoos, Holger and Kaminski, Roland and Lindauer, Marius and Schaub, Torsten H.}, title = {aspeed: Solver scheduling via answer set programming}, series = {Theory and practice of logic programming}, volume = {15}, journal = {Theory and practice of logic programming}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068414000015}, pages = {117 -- 142}, year = {2015}, abstract = {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.}, language = {en} } @article{FichteSzeider2015, author = {Fichte, Johannes Klaus and Szeider, Stefan}, title = {Backdoors to tractable answer set programming}, series = {Artificial intelligence}, volume = {220}, journal = {Artificial intelligence}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0004-3702}, doi = {10.1016/j.artint.2014.12.001}, pages = {64 -- 103}, year = {2015}, abstract = {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.}, language = {en} } @phdthesis{Jung2015, author = {Jung, J{\"o}rg}, title = {Efficient credit based server load balancing}, school = {Universit{\"a}t Potsdam}, pages = {353}, year = {2015}, language = {en} } @article{WaltonGordon2015, author = {Walton, Douglas and Gordon, Thomas F.}, title = {Formalizing informal logic}, series = {Informal logic : reasoning and argumentation in theory and practics}, volume = {35}, journal = {Informal logic : reasoning and argumentation in theory and practics}, number = {4}, publisher = {Centre for Research in Reasoning, Argumentation and Rhetoric, University of Windsor}, address = {Windsor}, issn = {0824-2577}, pages = {508 -- 538}, year = {2015}, abstract = {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.}, language = {en} } @phdthesis{Kaufmann2015, author = {Kaufmann, Benjamin}, title = {High performance answer set solving}, pages = {182}, year = {2015}, language = {en} } @article{GruenewaldMeinel2015, author = {Gr{\"u}newald, Franka and Meinel, Christoph}, title = {Implementation and Evaluation of Digital E-Lecture Annotation in Learning Groups to Foster Active Learning}, series = {IEEE transactions on learning technologies}, volume = {8}, journal = {IEEE transactions on learning technologies}, number = {3}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Los Alamitos}, issn = {1939-1382}, doi = {10.1109/TLT.2015.2396042}, pages = {286 -- 298}, year = {2015}, abstract = {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.}, language = {en} } @article{VidelaGuziolowskiEduatietal.2015, author = {Videla, Santiago and Guziolowski, Carito and Eduati, Federica and Thiele, Sven and Gebser, Martin and Nicolas, Jacques and Saez-Rodriguez, Julio and Schaub, Torsten H. and Siegel, Anne}, title = {Learning Boolean logic models of signaling networks with ASP}, series = {Theoretical computer science}, volume = {599}, journal = {Theoretical computer science}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3975}, doi = {10.1016/j.tcs.2014.06.022}, pages = {79 -- 101}, year = {2015}, abstract = {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.}, language = {en} } @phdthesis{Wust2015, author = {Wust, Johannes}, title = {Mixed workload managment for in-memory databases}, pages = {VIII, 167}, year = {2015}, language = {en} } @incollection{KnothKiyKlein2015, author = {Knoth, Alexander Henning and Kiy, Alexander and Klein, M.}, title = {Mobil in und aus Situationen lernen: Erste Erfahrungen zum Studieneinstieg von Studierenden verschiedener Fachrichtungen}, series = {Lecture Notes in Informatics (LNI), Proceedings - Series of the Gesellschaft f{\"u}r Informatik}, booktitle = {Lecture Notes in Informatics (LNI), Proceedings - Series of the Gesellschaft f{\"u}r Informatik}, number = {247}, publisher = {Gesellschaft fur Informatik e.V.}, address = {Bonn}, isbn = {978-3-88579-641-1}, issn = {1617-5468}, publisher = {Universit{\"a}t Potsdam}, pages = {81 -- 93}, year = {2015}, language = {de} } @phdthesis{Hosp2015, author = {Hosp, Sven}, title = {Modifizierte Cross-Party Codes zur schnellen Mehrbit-Fehlerkorrektur}, pages = {105}, year = {2015}, language = {de} } @article{ChildsGrimbsSelbig2015, author = {Childs, Dorothee and Grimbs, Sergio and Selbig, Joachim}, title = {Refined elasticity sampling for Monte Carlo-based identification of stabilizing network patterns}, series = {Bioinformatics}, volume = {31}, journal = {Bioinformatics}, number = {12}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {1367-4803}, doi = {10.1093/bioinformatics/btv243}, pages = {214 -- 220}, year = {2015}, abstract = {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.}, language = {en} } @article{LemckeHaedgeZenderetal.2015, author = {Lemcke, Stefanie and Haedge, Kora and Zender, Raphael and Lucke, Ulrike}, title = {RouteMe: a multilevel pervasive game on mobile ad hoc routing}, series = {Personal and ubiquitous computing}, volume = {19}, journal = {Personal and ubiquitous computing}, number = {3-4}, publisher = {Springer}, address = {London}, issn = {1617-4909}, doi = {10.1007/s00779-015-0843-2}, pages = {537 -- 549}, year = {2015}, abstract = {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.}, language = {en} } @article{LamprechtMargaria2015, author = {Lamprecht, Anna-Lena and Margaria, Tiziana}, title = {Scientific workflows and XMDD}, series = {Process design for natural scientists}, journal = {Process design for natural scientists}, editor = {Lamprecht, Anna-Lena and Margaria, Tiziana}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-662-45006-2}, pages = {1 -- 13}, year = {2015}, language = {en} } @article{OmranianMuellerRoeberNikoloski2015, author = {Omranian, Nooshin and M{\"u}ller-R{\"o}ber, Bernd and Nikoloski, Zoran}, title = {Segmentation of biological multivariate time-series data}, series = {Scientific reports}, volume = {5}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep08937}, pages = {6}, year = {2015}, abstract = {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.}, language = {en} } @article{JungKiertscherMenskietal.2015, author = {Jung, J{\"o}rg and Kiertscher, Simon and Menski, Sebastian and Schnor, Bettina}, title = {Self-Adapting Load Balancing for DNS}, series = {Journal of networks}, volume = {10}, journal = {Journal of networks}, number = {4}, publisher = {Kluwer Academic Publishers}, address = {Oulu}, doi = {10.1109/SPECTS.2014.6879994}, pages = {222 -- 231}, year = {2015}, abstract = {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)).}, language = {en} } @book{PlattnerLeukert2015, author = {Plattner, Hasso and Leukert, Bernd}, title = {The in-memory revolution}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-16672-8}, pages = {275}, year = {2015}, abstract = {This book describes the next generation of business applications enabled by SAP's in-memory database, SAP HANA. In particular, the authors show the substantial changes introduced in S4/HANA by switching to SAP HANA. Using numerous examples and use cases from the authors' wealth of real-world experience, it illustrates the quantum leap in performance made possible by the new technology. The book is written by two of the most prominent actors in the area of business application systems: Hasso Plattner, co-founder of SAP and inaugurator of the Hasso Plattner Institute at the University of Potsdam, and Bernd Leukert, member of the Executive Board and the Global Managing Board of SAP. This clearly structured, highly illustrated book takes an exciting new technology and presents the practicality and success of first mover applications.}, language = {en} } @phdthesis{SadrAzodi2015, author = {Sadr-Azodi, Amir Shahab}, title = {Towards Real-time SIEM-based Network monitoring and Intrusion Detection through Advanced Event Normalization}, school = {Universit{\"a}t Potsdam}, pages = {144}, year = {2015}, language = {en} } @article{AhmadShoaibPrinetto2015, author = {Ahmad, Nadeem and Shoaib, Umar and Prinetto, Paolo}, title = {Usability of Online Assistance From Semiliterate Users' Perspective}, series = {International journal of human computer interaction}, volume = {31}, journal = {International journal of human computer interaction}, number = {1}, publisher = {Taylor \& Francis Group}, address = {Philadelphia}, issn = {1044-7318}, doi = {10.1080/10447318.2014.925772}, pages = {55 -- 64}, year = {2015}, language = {en} }