@article{KrasnovaVeltriSpengleretal.2013, author = {Krasnova, Hanna and Veltri, Natasha F. and Spengler, Klaus and G{\"u}nther, Oliver}, title = {"Deal of the Day" Platforms what drives Consumer loyalty?}, series = {Business \& information systems engineering : the international journal of Wirtschaftsinformatik}, volume = {5}, journal = {Business \& information systems engineering : the international journal of Wirtschaftsinformatik}, number = {3}, publisher = {Springer}, address = {Heidelberg}, issn = {1867-0202}, doi = {10.1007/s12599-013-0268-2}, pages = {165 -- 177}, year = {2013}, abstract = {"Deal of the Day" (DoD) platforms have quickly become popular by offering savings on local services, products and vacations. For merchants, these platforms represent a new marketing channel to advertise their products and services and attract new customers. DoD platform providers, however, struggle to maintaining a stable market share and profitability, because entry and switching costs are low. To sustain a competitive market position, DoD providers are looking for ways to build a loyal customer base. However, research examining the determinants of user loyalty in this novel context is scarce. To fill this gap, this study employs Grounded Theory methodology to develop a conceptual model of customer loyalty to a DoD provider. In the next step, qualitative insights are enriched and validated using quantitative data from a survey of 202 DoD users. The authors find that customer loyalty is in large part driven by monetary incentives, but can be eroded if impressions from merchant encounters are below expectations. In addition, enhancing the share of deals relevant for consumers, i.e. signal-to-noise ratio, and mitigating perceived risks of a transaction emerge as challenges. Beyond theoretical value, the results offer practical insights into how customer loyalty to a DoD provider can be promoted.}, language = {en} } @article{DelgrandeSchaubTompitsetal.2013, author = {Delgrande, James and Schaub, Torsten H. and Tompits, Hans and Woltran, Stefan}, title = {A model-theoretic approach to belief change in answer set programming}, series = {ACM transactions on computational logic}, volume = {14}, journal = {ACM transactions on computational logic}, number = {2}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {1529-3785}, doi = {10.1145/2480759.2480766}, pages = {46}, year = {2013}, abstract = {We address the problem of belief change in (nonmonotonic) logic programming under answer set semantics. Our formal techniques are analogous to those of distance-based belief revision in propositional logic. In particular, we build upon the model theory of logic programs furnished by SE interpretations, where an SE interpretation is a model of a logic program in the same way that a classical interpretation is a model of a propositional formula. Hence we extend techniques from the area of belief revision based on distance between models to belief change in logic programs. We first consider belief revision: for logic programs P and Q, the goal is to determine a program R that corresponds to the revision of P by Q, denoted P * Q. We investigate several operators, including (logic program) expansion and two revision operators based on the distance between the SE models of logic programs. It proves to be the case that expansion is an interesting operator in its own right, unlike in classical belief revision where it is relatively uninteresting. Expansion and revision are shown to satisfy a suite of interesting properties; in particular, our revision operators satisfy all or nearly all of the AGM postulates for revision. We next consider approaches for merging a set of logic programs, P-1,...,P-n. Again, our formal techniques are based on notions of relative distance between the SE models of the logic programs. Two approaches are examined. The first informally selects for each program P-i those models of P-i that vary the least from models of the other programs. The second approach informally selects those models of a program P-0 that are closest to the models of programs P-1,...,P-n. In this case, P-0 can be thought of as a set of database integrity constraints. We examine these operators with regards to how they satisfy relevant postulate sets. Last, we present encodings for computing the revision as well as the merging of logic programs within the same logic programming framework. This gives rise to a direct implementation of our approach in terms of off-the-shelf answer set solvers. These encodings also reflect the fact that our change operators do not increase the complexity of the base formalism.}, language = {en} } @article{SawadeBickelvonOertzenetal.2013, author = {Sawade, Christoph and Bickel, Steffen and von Oertzen, Timo and Scheffer, Tobias and Landwehr, Niels}, title = {Active evaluation of ranking functions based on graded relevance}, series = {Machine learning}, volume = {92}, journal = {Machine learning}, number = {1}, publisher = {Springer}, address = {Dordrecht}, issn = {0885-6125}, doi = {10.1007/s10994-013-5372-5}, pages = {41 -- 64}, year = {2013}, abstract = {Evaluating the quality of ranking functions is a core task in web search and other information retrieval domains. Because query distributions and item relevance change over time, ranking models often cannot be evaluated accurately on held-out training data. Instead, considerable effort is spent on manually labeling the relevance of query results for test queries in order to track ranking performance. We address the problem of estimating ranking performance as accurately as possible on a fixed labeling budget. Estimates are based on a set of most informative test queries selected by an active sampling distribution. Query labeling costs depend on the number of result items as well as item-specific attributes such as document length. We derive cost-optimal sampling distributions for the commonly used performance measures Discounted Cumulative Gain and Expected Reciprocal Rank. Experiments on web search engine data illustrate significant reductions in labeling costs.}, language = {en} } @article{MontavonBraunKruegeretal.2013, author = {Montavon, Gregoire and Braun, Mikio L. and Kr{\"u}ger, Tammo and M{\"u}ller, Klaus-Robert}, title = {Analyzing local structure in Kernel-Based learning}, series = {IEEE signal processing magazine}, volume = {30}, journal = {IEEE signal processing magazine}, number = {4}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Piscataway}, issn = {1053-5888}, doi = {10.1109/MSP.2013.2249294}, pages = {62 -- 74}, year = {2013}, language = {en} } @article{BanbaraSohTamuraetal.2013, author = {Banbara, Mutsunori and Soh, Takehide and Tamura, Naoyuki and Inoue, Katsumi and Schaub, Torsten H.}, title = {Answer set programming as a modeling language for course timetabling}, series = {Theory and practice of logic programming}, volume = {13}, journal = {Theory and practice of logic programming}, number = {2}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068413000495}, pages = {783 -- 798}, year = {2013}, abstract = {The course timetabling problem can be generally defined as the task of assigning a number of lectures to a limited set of timeslots and rooms, subject to a given set of hard and soft constraints. The modeling language for course timetabling is required to be expressive enough to specify a wide variety of soft constraints and objective functions. Furthermore, the resulting encoding is required to be extensible for capturing new constraints and for switching them between hard and soft, and to be flexible enough to deal with different formulations. In this paper, we propose to make effective use of ASP as a modeling language for course timetabling. We show that our ASP-based approach can naturally satisfy the above requirements, through an ASP encoding of the curriculum-based course timetabling problem proposed in the third track of the second international timetabling competition (ITC-2007). Our encoding is compact and human-readable, since each constraint is individually expressed by either one or two rules. Each hard constraint is expressed by using integrity constraints and aggregates of ASP. Each soft constraint S is expressed by rules in which the head is the form of penalty (S, V, C), and a violation V and its penalty cost C are detected and calculated respectively in the body. We carried out experiments on four different benchmark sets with five different formulations. We succeeded either in improving the bounds or producing the same bounds for many combinations of problem instances and formulations, compared with the previous best known bounds.}, language = {en} } @article{HolzBergerSchroeder2013, author = {Holz, Jan and Berger, Nadine and Schroeder, Ulrike}, title = {Anwendungsorientierte Gestaltung eines Informatik-Vorkurses als Studienmotivator}, series = {Commentarii informaticae didacticae : (CID)}, journal = {Commentarii informaticae didacticae : (CID)}, number = {5}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-0844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64871}, pages = {56 -- 66}, year = {2013}, abstract = {Zur Unterst{\"u}tzung von Studierenden in der Studieneingangsphase wurde an der RWTH Aachen ein neuartiger und motivierender Einstieg in den Vorkurs Informatik entwickelt und zum Wintersemester 2011/12 erprobt. Dabei wurde die grafische Programmierung mittels App Inventor eingef{\"u}hrt, die zur Umsetzung anwendungsbezogener Projekte genutzt wurde. In diesem Beitrag werden die Motivation f{\"u}r die Neugestaltung, das Konzept und die Evaluation des Testlaufs beschrieben. Diese dienen als Grundlage f{\"u}r eine vollst{\"a}ndige Neukonzeption des Vorkurses f{\"u}r das Wintersemester 2012/2013.}, language = {de} } @article{KiertscherZinkeSchnor2013, author = {Kiertscher, Simon and Zinke, J{\"o}rg and Schnor, Bettina}, title = {CHERUB power consumption aware cluster resource management}, series = {Cluster computing : the journal of networks, software tools and applications}, volume = {16}, journal = {Cluster computing : the journal of networks, software tools and applications}, number = {1}, publisher = {Springer}, address = {New York}, issn = {1386-7857}, doi = {10.1007/s10586-011-0176-5}, pages = {55 -- 63}, year = {2013}, abstract = {This paper presents an evaluation of ACPI energy saving modes, and deduces the design and implementation of an energy saving daemon for clusters called cherub. The design of the cherub daemon is modular and extensible. Since the only requirement is a central approach for resource management, cherub is suited for Server Load Balancing (SLB) clusters managed by dispatchers like Linux Virtual Server (LVS), as well as for High Performance Computing (HPC) clusters. Our experimental results show that cherub's scheduling algorithm works well, i.e. it will save energy, if possible, and avoids state-flapping.}, language = {en} } @article{SteinertCassouHirschfeld2013, author = {Steinert, Bastian and Cassou, Damien and Hirschfeld, Robert}, title = {CoExist overcoming aversion to change preserving immediate access to source code and run-time information of previous development states}, series = {ACM SIGPLAN notices}, volume = {48}, journal = {ACM SIGPLAN notices}, number = {2}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {0362-1340}, doi = {10.1145/2480360.2384591}, pages = {107 -- 117}, year = {2013}, abstract = {Programmers make many changes to the program to eventually find a good solution for a given task. In this course of change, every intermediate development state can of value, when, for example, a promising ideas suddenly turn out inappropriate or the interplay of objects turns out more complex than initially expected before making changes. Programmers would benefit from tool support that provides immediate access to source code and run-time of previous development states of interest. We present IDE extensions, implemented for Squeak/Smalltalk, to preserve, retrieve, and work with this information. With such tool support, programmers can work without worries because they can rely on tools that help them with whatever their explorations will reveal. They no longer have to follow certain best practices only to avoid undesired consequences of changing code.}, language = {en} } @article{Petre2013, author = {Petre, Marian}, title = {Computing is not a spectator sport}, series = {Commentarii informaticae didacticae : (CID)}, journal = {Commentarii informaticae didacticae : (CID)}, number = {5}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-0844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-65045}, pages = {155 -- 159}, year = {2013}, abstract = {This talk will describe My Digital Life (TU100), a distance learning module that introduces computer science through immediate engagement with ubiquitous computing (ubicomp). This talk will describe some of the principles and concepts we have adopted for this modern computing introduction: the idea of the 'informed digital citizen'; engagement through narrative; playful pedagogy; making the power of ubicomp available to novices; setting technical skills in real contexts. It will also trace how the pedagogy is informed by experiences and research in Computer Science education.}, language = {en} } @article{KnobelsdorfKreitz2013, author = {Knobelsdorf, Maria and Kreitz, Christoph}, title = {Ein konstruktivistischer Lehransatz f{\"u}r die Einf{\"u}hrungsveranstaltung der Theoretischen Informatik}, series = {Commentarii informaticae didacticae : (CID)}, journal = {Commentarii informaticae didacticae : (CID)}, number = {5}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-0844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64845}, pages = {21 -- 32}, year = {2013}, abstract = {Ausgehend von einem sozial-konstruktivistischen Verst{\"a}ndnis von Lernprozessen und unter der besonderen Ber{\"u}cksichtigung der durch die Bologna-Studienreform angeregten Kompetenzorientierung, haben wir in den letzten Jahren einen hochschuldidaktischen Ansatz f{\"u}r die Einf{\"u}hrungsveranstaltung im Bereich der Theoretischen Informatik an der Universit{\"a}t Potsdam entwickelt und praktisch erprobt. Nach zahlreichen Experimenten und mit einer Durchfallquote von zuletzt 6\% im Wintersemester 2011/2012 haben wir den Eindruck, dass der Ansatz den Studierenden jene Lernumgebung und -anregung bietet, die ihnen hilft, die entsprechenden Fachkompetenzen in der Veranstaltung zu entwickeln. In diesem Artikel stellen wir unseren Ansatz vor und skizzieren abschlie{\"y}end, wie wir diesen im n{\"a}chsten Wintersemester empirisch evaluieren werden.}, language = {de} }