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 - Baier, Thomas A1 - Mendling, Jan A1 - Weske, Mathias T1 - Bridging abstraction layers in process mining JF - Information systems N2 - While the maturity of process mining algorithms increases and more process mining tools enter the market, process mining projects still face the problem of different levels of abstraction when comparing events with modeled business activities. Current approaches for event log abstraction try to abstract from the events in an automated way that does not capture the required domain knowledge to fit business activities. This can lead to misinterpretation of discovered process models. We developed an approach that aims to abstract an event log to the same abstraction level that is needed by the business. We use domain knowledge extracted from existing process documentation to semi-automatically match events and activities. Our abstraction approach is able to deal with n:m relations between events and activities and also supports concurrency. We evaluated our approach in two case studies with a German IT outsourcing company. (C) 2014 Elsevier Ltd. All rights reserved. KW - Process mining KW - Abstraction KW - Event mapping Y1 - 2014 U6 - https://doi.org/10.1016/j.is.2014.04.004 SN - 0306-4379 SN - 1873-6076 VL - 46 SP - 123 EP - 139 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Giese, Holger A1 - Hildebrandt, Stephan A1 - Lambers, Leen T1 - Bridging the gap between formal semantics and implementation of triple graph grammars JF - Software and systems modeling N2 - The correctness of model transformations is a crucial element for model-driven engineering of high-quality software. A prerequisite to verify model transformations at the level of the model transformation specification is that an unambiguous formal semantics exists and that the implementation of the model transformation language adheres to this semantics. However, for existing relational model transformation approaches, it is usually not really clear under which constraints particular implementations really conform to the formal semantics. In this paper, we will bridge this gap for the formal semantics of triple graph grammars (TGG) and an existing efficient implementation. While the formal semantics assumes backtracking and ignores non-determinism, practical implementations do not support backtracking, require rule sets that ensure determinism, and include further optimizations. Therefore, we capture how the considered TGG implementation realizes the transformation by means of operational rules, define required criteria, and show conformance to the formal semantics if these criteria are fulfilled. We further outline how static and runtime checks can be employed to guarantee these criteria. Y1 - 2014 U6 - https://doi.org/10.1007/s10270-012-0247-y SN - 1619-1366 SN - 1619-1374 VL - 13 IS - 1 SP - 273 EP - 299 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Weiher, Marcel A1 - Hirschfeld, Robert T1 - Polymorphic identifiers: uniform resource access in objective-smalltalk JF - ACM SIGPLAN notices N2 - In object-oriented programming, polymorphic dispatch of operations decouples clients from specific providers of services and allows implementations to be modified or substituted without affecting clients. The Uniform Access Principle (UAP) tries to extend these qualities to resource access by demanding that access to state be indistinguishable from access to operations. Despite language features supporting the UAP, the overall goal of substitutability has not been achieved for either alternative resources such as keyed storage, files or web pages, or for alternate access mechanisms: specific kinds of resources are bound to specific access mechanisms and vice versa. Changing storage or access patterns either requires changes to both clients and service providers and trying to maintain the UAP imposes significant penalties in terms of code-duplication and/or performance overhead. We propose introducing first class identifiers as polymorphic names for storage locations to solve these problems. With these Polymorphic Identifiers, we show that we can provide uniform access to a wide variety of resource types as well as storage and access mechanisms, whether parametrized or direct, without affecting client code, without causing code duplication or significant performance penalties. KW - Identifiers KW - REST KW - Uniform Access Principle KW - Extensibility Y1 - 2014 U6 - https://doi.org/10.1145/2508168.2508169 SN - 0362-1340 SN - 1558-1160 VL - 49 IS - 2 SP - 61 EP - 71 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Schaub, Torsten H. T1 - Conflict-driven answer set solving: From theory to practice JF - Artificial intelligence N2 - We introduce an approach to computing answer sets of logic programs, based on concepts successfully applied in Satisfiability (SAT) checking. The idea is to view inferences in Answer Set Programming (ASP) as unit propagation on nogoods. This provides us with a uniform constraint-based framework capturing diverse inferences encountered in ASP solving. Moreover, our approach allows us to apply advanced solving techniques from the area of SAT. As a result, we present the first full-fledged algorithmic framework for native conflict-driven ASP solving. Our approach is implemented in the ASP solver clasp that has demonstrated its competitiveness and versatility by winning first places at various solver contests. KW - Answer set programming KW - Logic programming KW - Nonmonotonic reasoning Y1 - 2012 U6 - https://doi.org/10.1016/j.artint.2012.04.001 SN - 0004-3702 VL - 187 IS - 8 SP - 52 EP - 89 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ostrowski, Max A1 - Schaub, Torsten H. T1 - ASP modulo CSP The clingcon system JF - Theory and practice of logic programming N2 - We present the hybrid ASP solver clingcon, combining the simple modeling language and the high performance Boolean solving capacities of Answer Set Programming (ASP) with techniques for using non-Boolean constraints from the area of Constraint Programming (CP). The new clingcon system features an extended syntax supporting global constraints and optimize statements for constraint variables. The major technical innovation improves the interaction between ASP and CP solver through elaborated learning techniques based on irreducible inconsistent sets. A broad empirical evaluation shows that these techniques yield a performance improvement of an order of magnitude. Y1 - 2012 U6 - https://doi.org/10.1017/S1471068412000142 SN - 1471-0684 VL - 12 SP - 485 EP - 503 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Schaub, Torsten H. T1 - Multi-threaded ASP solving with clasp JF - Theory and practice of logic programming N2 - We present the new multi-threaded version of the state-of-the-art answer set solver clasp. We detail its component and communication architecture and illustrate how they support the principal functionalities of clasp. Also, we provide some insights into the data representation used for different constraint types handled by clasp. All this is accompanied by an extensive experimental analysis of the major features related to multi-threading in clasp. Y1 - 2012 U6 - https://doi.org/10.1017/S1471068412000166 SN - 1471-0684 VL - 12 IS - 8 SP - 525 EP - 545 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Hoos, Holger A1 - Lindauer, Marius A1 - Schaub, Torsten H. T1 - claspfolio 2 BT - advances in algorithm selection for answer set programming JF - Theory and practice of logic programming N2 - Building on the award-winning, portfolio-based ASP solver claspfolio, we present claspfolio 2, a modular and open solver architecture that integrates several different portfolio-based algorithm selection approaches and techniques. The claspfolio 2 solver framework supports various feature generators, solver selection approaches, solver portfolios, as well as solver-schedule-based pre-solving techniques. The default configuration of claspfolio 2 relies on a light-weight version of the ASP solver clasp to generate static and dynamic instance features. The flexible open design of claspfolio 2 is a distinguishing factor even beyond ASP. As such, it provides a unique framework for comparing and combining existing portfolio-based algorithm selection approaches and techniques in a single, unified framework. Taking advantage of this, we conducted an extensive experimental study to assess the impact of different feature sets, selection approaches and base solver portfolios. In addition to gaining substantial insights into the utility of the various approaches and techniques, we identified a default configuration of claspfolio 2 that achieves substantial performance gains not only over clasp's default configuration and the earlier version of claspfolio, but also over manually tuned configurations of clasp. Y1 - 2014 U6 - https://doi.org/10.1017/S1471068414000210 SN - 1471-0684 SN - 1475-3081 VL - 14 SP - 569 EP - 585 PB - Cambridge Univ. Press CY - New York 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 H. 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 - INPR A1 - Kröning, Daniel A1 - Margaria, Tiziana A1 - Woodcock, Jim T1 - Untitled T2 - Formal aspects of computing : the international journal of formal methods Y1 - 2011 U6 - https://doi.org/10.1007/s00165-011-0201-8 SN - 0934-5043 VL - 23 IS - 5 SP - 585 EP - 588 PB - Springer CY - New York ER - TY - JOUR A1 - Jörges, Sven A1 - Margaria, Tiziana A1 - Steffen, Bernhard T1 - Assuring property conformance of code generators via model checking JF - Formal aspects of computing : the international journal of formal methods N2 - Automatic code generation is an essential cornerstone of today's model-driven approaches to software engineering. Thus a key requirement for the success of this technique is the reliability and correctness of code generators. This article describes how we employ standard model checking-based verification to check that code generator models developed within our code generation framework Genesys conform to (temporal) properties. Genesys is a graphical framework for the high-level construction of code generators on the basis of an extensible library of well-defined building blocks along the lines of the Extreme Model-Driven Development paradigm. We will illustrate our verification approach by examining complex constraints for code generators, which even span entire model hierarchies. We also show how this leads to a knowledge base of rules for code generators, which we constantly extend by e.g. combining constraints to bigger constraints, or by deriving common patterns from structurally similar constraints. In our experience, the development of code generators with Genesys boils down to re-instantiating patterns or slightly modifying the graphical process model, activities which are strongly supported by verification facilities presented in this article. KW - Extreme Model-Driven Development KW - Code generation KW - Model checking KW - Verification Y1 - 2011 U6 - https://doi.org/10.1007/s00165-010-0169-9 SN - 0934-5043 VL - 23 IS - 5 SP - 589 EP - 606 PB - Springer CY - New York ER - TY - JOUR A1 - Gebser, Martin A1 - Schaub, Torsten H. A1 - Thiele, Sven A1 - Veber, Philippe T1 - Detecting inconsistencies in large biological networks with answer set programming JF - Theory and practice of logic programming N2 - We introduce an approach to detecting inconsistencies in large biological networks by using answer set programming. To this end, we build upon a recently proposed notion of consistency between biochemical/genetic reactions and high-throughput profiles of cell activity. We then present an approach based on answer set programming to check the consistency of large-scale data sets. Moreover, we extend this methodology to provide explanations for inconsistencies by determining minimal representations of conflicts. In practice, this can be used to identify unreliable data or to indicate missing reactions. KW - answer set programming KW - bioinformatics KW - consistency KW - diagnosis Y1 - 2011 U6 - https://doi.org/10.1017/S1471068410000554 SN - 1471-0684 VL - 11 IS - 5-6 SP - 323 EP - 360 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Rabenalt, Thomas A1 - Goessel, Michael A1 - Leininger, Andreas T1 - Masking of X-Values by use of a hierarchically configurable register JF - Journal of electronic testing : theory and applications N2 - In this paper we consider masking of unknowns (X-values) for VLSI circuits. We present a new hierarchical method of X-masking which is a major improvement of the method proposed in [4], called WIDE1. By the method proposed, the number of observable scan cells is optimized and data volume for X-masking can be significantly reduced in comparison to WIDEL This is demonstrated for three industrial designs. In cases where all X-values have to be masked the novel approach is especially efficient. KW - Masking of X-values KW - Hierarchically configurable mask register Y1 - 2011 U6 - https://doi.org/10.1007/s10836-010-5179-2 SN - 0923-8174 VL - 27 IS - 1 SP - 31 EP - 41 PB - Springer CY - Dordrecht ER - TY - GEN A1 - Patil, Kaustubh R. A1 - Haider, Peter A1 - Pope, Phillip B. A1 - Turnbaugh, Peter J. A1 - Morrison, Mark A1 - Scheffer, Tobias A1 - McHardy, Alice C. T1 - Taxonomic metagenome sequence assignment with structured output models T2 - Nature methods : techniques for life scientists and chemists Y1 - 2011 U6 - https://doi.org/10.1038/nmeth0311-191 SN - 1548-7091 VL - 8 IS - 3 SP - 191 EP - 192 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Bordihn, Henning A1 - Holzer, Markus A1 - Kutrib, Martin T1 - Decidability of operation problems for TOL languages and subclasses JF - Information and computation N2 - We investigate the decidability of the operation problem for TOL languages and subclasses. Fix an operation on formal languages. Given languages from the family considered (OL languages, TOL languages, or their propagating variants), is the application of this operation to the given languages still a language that belongs to the same language family? Observe, that all the Lindenmayer language families in question are anti-AFLs, that is, they are not closed under homomorphisms, inverse homomorphisms, intersection with regular languages, union, concatenation, and Kleene closure. Besides these classical operations we also consider intersection and substitution, since the language families under consideration are not closed under these operations, too. We show that for all of the above mentioned language operations, except for the Kleene closure, the corresponding operation problems of OL and TOL languages and their propagating variants are not even semidecidable. The situation changes for unary OL languages. In this case we prove that the operation problems with respect to Kleene star, complementation, and intersection with regular sets are decidable. KW - L systems KW - Operation problem KW - Decidability KW - Unary languages Y1 - 2011 U6 - https://doi.org/10.1016/j.ic.2010.11.008 SN - 0890-5401 VL - 209 IS - 3 SP - 344 EP - 352 PB - Elsevier CY - San Diego ER - TY - INPR A1 - Rosamond, Frances A1 - Bardohl, Roswitha A1 - Diehl, Stephan A1 - Geisler, Uwe A1 - Bolduan, Gordon A1 - Lessmoellmann, Annette A1 - Schwill, Andreas A1 - Stege, Ulrike T1 - Virtual extension reaching out to the media become a computer science ambassador T2 - Communications of the ACM / Association for Computing Machinery Y1 - 2011 U6 - https://doi.org/10.1145/1897852.1897880 SN - 0001-0782 VL - 54 IS - 3 SP - 113 EP - 116 PB - Association for Computing Machinery CY - New York ER - TY - JOUR A1 - Troeger, Peter A1 - Merzky, Andre T1 - Towards standardized job submission and control in infrastructure clouds JF - Journal of grid computing N2 - The submission and management of computational jobs is a traditional part of utility computing environments. End users and developers of domain-specific software abstractions often have to deal with the heterogeneity of such batch processing systems. This lead to a number of application programming interface and job description standards in the past, which are implemented and established for cluster and Grid systems. With the recent rise of cloud computing as new utility computing paradigm, the standardized access to batch processing facilities operated on cloud resources becomes an important issue. Furthermore, the design of such a standard has to consider a tradeoff between feature completeness and the achievable level of interoperability. The article discusses this general challenge, and presents some existing standards with traditional cluster and Grid computing background that may be applicable to cloud environments. We present OCCI-DRMAA as one approach for standardized access to batch processing facilities hosted in a cloud. KW - Cloud KW - IaaS KW - DRMS KW - DRMAA KW - OCCI KW - Batch processing KW - Job submission KW - Job monitoring Y1 - 2014 U6 - https://doi.org/10.1007/s10723-013-9275-2 SN - 1570-7873 SN - 1572-9184 VL - 12 IS - 1 SP - 111 EP - 125 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Fabian, Benjamin A1 - Kunz, Steffen A1 - Konnegen, Marcel A1 - Müller, Sebastian A1 - Günther, Oliver T1 - Access control for semantic data federations in industrial product-lifecycle management JF - Computers in industry : an international, application oriented research journal N2 - Information integration across company borders becomes increasingly important for the success of product lifecycle management in industry and complex supply chains. Semantic technologies are about to play a crucial role in this integrative process. However, cross-company data exchange requires mechanisms to enable fine-grained access control definition and enforcement, preventing unauthorized leakage of confidential data across company borders. Currently available semantic repositories are not sufficiently equipped to satisfy this important requirement. This paper presents an infrastructure for controlled sharing of semantic data between cooperating business partners. First, we motivate the need for access control in semantic data federations by a case study in the industrial service sector. Furthermore, we present an architecture for controlling access to semantic repositories that is based on our newly developed SemForce security service. Finally, we show the practical feasibility of this architecture by an implementation and several performance experiments. KW - Access control KW - Data federation KW - Information integration KW - Product lifecycle management KW - Semantic data Y1 - 2012 U6 - https://doi.org/10.1016/j.compind.2012.08.015 SN - 0166-3615 VL - 63 IS - 9 SP - 930 EP - 940 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Catchpole, Gareth A1 - Platzer, Alexander A1 - Weikert, Cornelia A1 - Kempkensteffen, Carsten A1 - Johannsen, Manfred A1 - Krause, Hans A1 - Jung, Klaus A1 - Miller, Kurt A1 - Willmitzer, Lothar A1 - Selbig, Joachim A1 - Weikert, Steffen T1 - Metabolic profiling reveals key metabolic features of renal cell carcinoma JF - Journal of cellular and molecular medicine : a journal of translational medicine N2 - Recent evidence suggests that metabolic changes play a pivotal role in the biology of cancer and in particular renal cell carcinoma (RCC). Here, a global metabolite profiling approach was applied to characterize the metabolite pool of RCC and normal renal tissue. Advanced decision tree models were applied to characterize the metabolic signature of RCC and to explore features of metastasized tumours. The findings were validated in a second independent dataset. Vitamin E derivates and metabolites of glucose, fatty acid, and inositol phosphate metabolism determined the metabolic profile of RCC. alpha-tocopherol, hippuric acid, myoinositol, fructose-1-phosphate and glucose-1-phosphate contributed most to the tumour/normal discrimination and all showed pronounced concentration changes in RCC. The identified metabolic profile was characterized by a low recognition error of only 5% for tumour versus normal samples. Data on metastasized tumours suggested a key role for metabolic pathways involving arachidonic acid, free fatty acids, proline, uracil and the tricarboxylic acid cycle. These results illustrate the potential of mass spectroscopy based metabolomics in conjunction with sophisticated data analysis methods to uncover the metabolic phenotype of cancer. Differentially regulated metabolites, such as vitamin E compounds, hippuric acid and myoinositol, provide leads for the characterization of novel pathways in RCC. KW - kidney cancer KW - metabolism KW - metabolomics KW - metastasis Y1 - 2011 U6 - https://doi.org/10.1111/j.1582-4934.2009.00939.x SN - 1582-1838 VL - 15 IS - 1 SP - 109 EP - 118 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Brückner, Michael A1 - Kanzow, Christian A1 - Scheffer, Tobias T1 - Static prediction games for adversarial learning problems JF - Journal of machine learning research N2 - The standard assumption of identically distributed training and test data is violated when the test data are generated in response to the presence of a predictive model. This becomes apparent, for example, in the context of email spam filtering. Here, email service providers employ spam filters, and spam senders engineer campaign templates to achieve a high rate of successful deliveries despite the filters. We model the interaction between the learner and the data generator as a static game in which the cost functions of the learner and the data generator are not necessarily antagonistic. We identify conditions under which this prediction game has a unique Nash equilibrium and derive algorithms that find the equilibrial prediction model. We derive two instances, the Nash logistic regression and the Nash support vector machine, and empirically explore their properties in a case study on email spam filtering. KW - static prediction games KW - adversarial classification KW - Nash equilibrium Y1 - 2012 SN - 1532-4435 VL - 13 SP - 2617 EP - 2654 PB - Microtome Publishing CY - Cambridge, Mass. ER - TY - JOUR A1 - Gebser, Martin A1 - Lee, Joohyung A1 - Lierler, Yuliya T1 - On elementary loops of logic programs JF - Theory and practice of logic programming N2 - Using the notion of an elementary loop, Gebser and Schaub (2005. Proceedings of the Eighth International Conference on Logic Programming and Nonmonotonic Reasoning (LPNMR'05), 53-65) refined the theorem on loop formulas attributable to Lin and Zhao (2004) by considering loop formulas of elementary loops only. In this paper, we reformulate the definition of an elementary loop, extend it to disjunctive programs, and study several properties of elementary loops, including how maximal elementary loops are related to minimal unfounded sets. The results provide useful insights into the stable model semantics in terms of elementary loops. For a nondisjunctive program, using a graph-theoretic characterization of an elementary loop, we show that the problem of recognizing an elementary loop is tractable. On the other hand, we also show that the corresponding problem is coNP-complete for a disjunctive program. Based on the notion of an elementary loop, we present the class of Head-Elementary-loop-Free (HEF) programs, which strictly generalizes the class of Head-Cycle-Free (HCF) programs attributable to Ben-Eliyahu and Dechter (1994. Annals of Mathematics and Artificial Intelligence 12, 53-87). Like an Ha: program, an HEF program can be turned into an equivalent nondisjunctive program in polynomial time by shifting head atoms into the body. KW - stable model semantics KW - loop formulas KW - unfounded sets Y1 - 2011 U6 - https://doi.org/10.1017/S1471068411000019 SN - 1471-0684 VL - 11 IS - 2 SP - 953 EP - 988 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Bordihn, Henning A1 - Kutrib, Martin A1 - Malcher, Andreas T1 - Undecidability and hierarchy results for parallel communicating finite automata JF - International journal of foundations of computer science N2 - Parallel communicating finite automata (PCFAs) are systems of several finite state automata which process a common input string in a parallel way and are able to communicate by sending their states upon request. We consider deterministic and nondeterministic variants and distinguish four working modes. It is known that these systems in the most general mode are as powerful as one-way multi-head finite automata. It is additionally known that the number of heads corresponds to the number of automata in PCFAs in a constructive way. Thus, undecidability results as well as results on the hierarchies induced by the number of heads carry over from multi-head finite automata to PCFAs in the most general mode. Here, we complement these undecidability and hierarchy results also for the remaining working modes. In particular, we show that classical decidability questions are not semi-decidable for any type of PCFAs under consideration. Moreover, it is proven that the number of automata in the system induces infinite hierarchies for deterministic and nondeterministic PCFAs in three working modes. KW - Automata systems KW - cooperating systems KW - formal languages KW - decidability questions Y1 - 2011 U6 - https://doi.org/10.1142/S0129054111008891 SN - 0129-0541 VL - 22 IS - 7 SP - 1577 EP - 1592 PB - World Scientific CY - Singapore ER - TY - JOUR A1 - Srinivasan, K. A1 - Senthilkumar, D. V. A1 - Mohamed, I. Raja A1 - Murali, K. A1 - Lakshmanan, M. A1 - Kurths, Jürgen T1 - Anticipating, complete and lag synchronizations in RC phase-shift network based coupled Chua's circuits without delay JF - Chaos : an interdisciplinary journal of nonlinear science N2 - We construct a new RC phase shift network based Chua's circuit, which exhibits a period-doubling bifurcation route to chaos. Using coupled versions of such a phase-shift network based Chua's oscillators, we describe a new method for achieving complete synchronization (CS), approximate lag synchronization (LS), and approximate anticipating synchronization (AS) without delay or parameter mismatch. Employing the Pecora and Carroll approach, chaos synchronization is achieved in coupled chaotic oscillators, where the drive system variables control the response system. As a result, AS or LS or CS is demonstrated without using a variable delay line both experimentally and numerically. Y1 - 2012 U6 - https://doi.org/10.1063/1.4711375 SN - 1054-1500 VL - 22 IS - 2 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Kaminski, Roland A1 - Ostrowski, Max A1 - Schaub, Torsten H. A1 - Schneider, Marius T1 - Potassco the Potsdam answer set solving collection JF - AI communications : AICOM ; the European journal on artificial intelligence N2 - This paper gives an overview of the open source project Potassco, the Potsdam Answer Set Solving Collection, bundling tools for Answer Set Programming developed at the University of Potsdam. KW - Answer set programming KW - declarative problem solving Y1 - 2011 U6 - https://doi.org/10.3233/AIC-2011-0491 SN - 0921-7126 VL - 24 IS - 2 SP - 107 EP - 124 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Gebser, Martin A1 - Sabuncu, Orkunt A1 - Schaub, Torsten H. T1 - An incremental answer set programming based system for finite model computation JF - AI communications : AICOM ; the European journal on artificial intelligence N2 - We address the problem of Finite Model Computation (FMC) of first-order theories and show that FMC can efficiently and transparently be solved by taking advantage of a recent extension of Answer Set Programming (ASP), called incremental Answer Set Programming (iASP). The idea is to use the incremental parameter in iASP programs to account for the domain size of a model. The FMC problem is then successively addressed for increasing domain sizes until an answer set, representing a finite model of the original first-order theory, is found. We implemented a system based on the iASP solver iClingo and demonstrate its competitiveness by showing that it slightly outperforms the winner of the FNT division of CADE's 2009 Automated Theorem Proving (ATP) competition on the respective benchmark collection. KW - Incremental answer set programming KW - finite model computation Y1 - 2011 U6 - https://doi.org/10.3233/AIC-2011-0496 SN - 0921-7126 VL - 24 IS - 2 SP - 195 EP - 212 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Bakera, Marco A1 - Margaria, Tiziana A1 - Renner, Clemens D. A1 - Steffen, Bernhard T1 - Game-Based model checking for reliable autonomy in space JF - Journal of aerospace computing, information, and communication N2 - Autonomy is an emerging paradigm for the design and implementation of managed services and systems. Self-managed aspects frequently concern the communication of systems with their environment. Self-management subsystems are critical, they should thus be designed and implemented as high-assurance components. Here, we propose to use GEAR, a game-based model checker for the full modal mu-calculus, and derived, more user-oriented logics, as a user friendly tool that can offer automatic proofs of critical properties of such systems. Designers and engineers can interactively investigate automatically generated winning strategies resulting from the games, this way exploring the connection between the property, the system, and the proof. The benefits of the approach are illustrated on a case study that concerns the ExoMars Rover. Y1 - 2011 U6 - https://doi.org/10.2514/1.32013 SN - 1940-3151 VL - 8 IS - 4 SP - 100 EP - 114 PB - American Institute of Aeronautics and Astronautics CY - Reston ER - TY - JOUR A1 - Arrighi, Pablo A1 - Nesme, Vincent A1 - Werner, Reinhard F. T1 - One-Dimensional quantum cellular automata JF - International journal of unconventional computing : non-classical computation and cellular automata N2 - We define and study quantum cellular automata (QCA). We show that they are reversible and that the neighborhood of the inverse is the opposite of the neighborhood. We also show that QCA always admit, modulo shifts, a two-layered block representation. Note that the same two-layered block representation result applies also over infinite configurations, as was previously shown for one-dimensional systems in the more elaborate formalism of operators algebras [18]. Here the proof is simpler and self-contained, moreover we discuss a counterexample QCA in higher dimensions. KW - cellular automata KW - quantum KW - neighborhood KW - block representation Y1 - 2011 SN - 1548-7199 VL - 7 IS - 4 SP - 223 EP - 244 PB - Old City Publishing Science CY - Philadelphia ER - TY - THES A1 - Ostrowski, Max T1 - Modern constraint answer set solving T1 - Moderne Constraint Antwortmengenprogrammierung N2 - Answer Set Programming (ASP) is a declarative problem solving approach, combining a rich yet simple modeling language with high-performance solving capabilities. Although this has already resulted in various applications, certain aspects of such applications are more naturally modeled using variables over finite domains, for accounting for resources, fine timings, coordinates, or functions. Our goal is thus to extend ASP with constraints over integers while preserving its declarative nature. This allows for fast prototyping and elaboration tolerant problem descriptions of resource related applications. The resulting paradigm is called Constraint Answer Set Programming (CASP). We present three different approaches for solving CASP problems. The first one, a lazy, modular approach combines an ASP solver with an external system for handling constraints. This approach has the advantage that two state of the art technologies work hand in hand to solve the problem, each concentrating on its part of the problem. The drawback is that inter-constraint dependencies cannot be communicated back to the ASP solver, impeding its learning algorithm. The second approach translates all constraints to ASP. Using the appropriate encoding techniques, this results in a very fast, monolithic system. Unfortunately, due to the large, explicit representation of constraints and variables, translation techniques are restricted to small and mid-sized domains. The third approach merges the lazy and the translational approach, combining the strength of both while removing their weaknesses. To this end, we enhance the dedicated learning techniques of an ASP solver with the inferences of the translating approach in a lazy way. That is, the important knowledge is only made explicit when needed. By using state of the art techniques from neighboring fields, we provide ways to tackle real world, industrial size problems. By extending CASP to reactive solving, we open up new application areas such as online planning with continuous domains and durations. N2 - Die Antwortmengenprogrammierung (ASP) ist ein deklarativer Ansatz zur Problemlösung. Eine ausdrucksstarke Modellierungssprache erlaubt es, Probleme einfach und flexibel zu beschreiben. Durch sehr effiziente Problemlösungstechniken, konnten bereits verschiedene Anwendungsgebiete erschlossen werden. Allerdings lassen sich Probleme mit Ressourcen besser mit Gleichungen über Ganze oder Reelle Zahlen lösen, anstatt mit reiner Boolescher Logik. In dieser Arbeit erweitern wir ASP mit Arithmetik über Ganze Zahlen zu Constraint Answer Set Programming (CASP). Unser Hauptaugenmerk liegt dabei auf der Erweiterung der Modellierungssprache mit Arithmetik, ohne Performanz oder Flexibilität einzubüßen. In einem ersten, bedarfsgesteuertem, modularen Ansatz kombinieren wir einen ASP Solver mit einem externen System zur Lösung von ganzzahligen Gleichungen. Der Vorteil dieses Ansatzes besteht darin, dass zwei verschiedene Technologien Hand in Hand arbeiten, wobei jede nur ihren Teil des Problems betrachten muss. Ein Nachteil der sich daraus ergibt ist jedoch, dass Abhängigkeiten zwischen den Gleichungen nicht an den ASP Solver kommuniziert werden können. Das beeinträchtigt die Lernfähigkeit des zu Grunde liegenden Algorithmus. Der zweite von uns verfolgte Ansatz übersetzt die ganzzahligen Gleichungen direkt nach ASP. Durch entsprechende Kodierungstechniken erhält man ein sehr effizientes, monolithisches System. Diese Übersetzung erfordert eine explizite Darstellung aller Variablen und Gleichungen. Daher ist dieser Ansatz nur für kleine bis mittlere Wertebereiche geeignet. Die dritte Methode, die wir in dieser Arbeit vorstellen, vereinigt die Vorteile der beiden vorherigen Ansätze und überwindet ihre Kehrseiten. Wir entwickeln einen lernenden Algorithmus, der die Arithmetik implizit lässt. Dies befreit uns davon, eine möglicherweise riesige Menge an Variablen und Formeln zu speichern, und erlaubt es uns gleichzeitig dieses Wissen zu nutzen. Das Ziel dieser Arbeit ist es, durch die Kombination hochmoderner Technologien, industrielle Anwendungsgebiete für ASP zu erschliessen. Die verwendeten Techniken erlauben eine Erweiterung von CASP mit reaktiven Elementen. Das heißt, dass das Lösen des Problems ein interaktiver Prozess wird. Das Problem kann dabei ständig verändert und erweitert werden, ohne dass Informationen verloren gehen oder neu berechnet werden müssen. Dies eröffnet uns neue Möglichkeiten, wie zum Beispiel reaktives Planen mit Ressourcen und Zeiten. KW - ASP (Answer Set Programming) KW - CASP (Constraint Answer Set Programming) KW - constraints KW - hybrid KW - SMT (SAT Modulo Theories) KW - Antwortmengenprogrammierung KW - hybrides Problemlösen Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407799 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 - THES A1 - Smirnov, Sergey T1 - Business process model abstraction T1 - Abstraktion von Geschäftsprozessmodellen N2 - Business process models are used within a range of organizational initiatives, where every stakeholder has a unique perspective on a process and demands the respective model. As a consequence, multiple process models capturing the very same business process coexist. Keeping such models in sync is a challenge within an ever changing business environment: once a process is changed, all its models have to be updated. Due to a large number of models and their complex relations, model maintenance becomes error-prone and expensive. Against this background, business process model abstraction emerged as an operation reducing the number of stored process models and facilitating model management. Business process model abstraction is an operation preserving essential process properties and leaving out insignificant details in order to retain information relevant for a particular purpose. Process model abstraction has been addressed by several researchers. The focus of their studies has been on particular use cases and model transformations supporting these use cases. This thesis systematically approaches the problem of business process model abstraction shaping the outcome into a framework. We investigate the current industry demand in abstraction summarizing it in a catalog of business process model abstraction use cases. The thesis focuses on one prominent use case where the user demands a model with coarse-grained activities and overall process ordering constraints. We develop model transformations that support this use case starting with the transformations based on process model structure analysis. Further, abstraction methods considering the semantics of process model elements are investigated. First, we suggest how semantically related activities can be discovered in process models-a barely researched challenge. The thesis validates the designed abstraction methods against sets of industrial process models and discusses the method implementation aspects. Second, we develop a novel model transformation, which combined with the related activity discovery allows flexible non-hierarchical abstraction. In this way this thesis advocates novel model transformations that facilitate business process model management and provides the foundations for innovative tool support. N2 - Geschäftsprozessmodelle werden in einer Fülle organisatorischer Initiativen eingesetzt, wobei verschiedene Stakeholder individuelle Ansprüche an die Sicht auf den jeweiligen Prozess haben. Dies führt dazu, dass zu einem Geschäftsprozess eine Vielzahl unterschiedlicher Modelle existiert. In einer sich ständig verändernden Geschäftsumgebung ist es daher schwierig, diese Vielzahl von Modellen konsistent zu halten: Ändert sich sich ein Prozess, müssen alle Modelle, die ihn beschreiben, aktualisiert werden. Aufgrund der schieren Menge an Prozessmodellen und ihrer komplexen Beziehungen zueinander, erhöhen sich Aufwand und Kosten zur Pflege aller Modelle enorm. Vor diesem Hintergrund ermöglicht die Abstraktion von Geschäftsprozessmodellen, die Menge der Modelle zu reduzieren und damit ihre Verwaltung zu vereinfachen. Abstraktion von Geschäftsprozessmodellen bezeichnet eine Transformation eines Prozessmodells, so dass es für einen bestimmten Zweck besonders geeignet ist. Bei der Abstraktion von Geschäftsprozessen bleiben essentielle Eigenschaften eines Modells erhalten, während irrelevante Eigenschaften verworfen werden. Mehrere Studien stellen Prozessmodellabstraktion in den Fokus und konzentrieren sich auf konkrete Anwendungsfälle, für die sie geeignete Transformationen entwickelt haben. Diese Dissertation untersucht das Problem der Prozessmodellabstraktion und systematisiert die Lösung in einem Framework. Aktuelle Anforderungen der Industrie an die Abstraktion von Prozessmodellen wurden recherchiert und in einem Katalog von Anwendungsfällen zusammengefasst, von denen ein besonderer für die weiteren Untersuchungen ausgewählt wurde. In diesem Fall erwartet der Nutzer ein Modell niedrigeren Detailgrades, in welchem die Kontrollflussbeziehungen des Ursprungsmodells erhalten bleiben. Beginnend bei Modelltransformationen, die auf der Analyse der Prozessmodellstruktur aufbauen, entwickeln wir neuartige Abstraktionsoperationen zur Unterstützung dieses Anwendungsfalles. Darüber hinaus untersuchen wir Abstraktionsmethoden, welche die Semantik von Prozessmodellelementen berücksichtigen. Zum einen zeigen wir, wie Aktivitäten ermittelt werden können, die miteinander in semantischer Beziehung stehen - ein Problem, das bisher nur unzureichend betrachtet wurde. Die vorgeschlagenen Methoden werden mithilfe industrieller Prozessmodellsammlungen validiert und deren Umsetzung diskutiert. Zum anderen schlagen wir eine innovative Modelltransformation zur nicht-hierarchischen Abstraktion von Prozessmodellen vor. Dieser liegt die Ermittlung in Beziehung stehender Aktivitäten zugrunde. Demzufolge präsentiert diese Arbeit eine originäre Methode zur Prozessmodellabstraktion, die die Verwaltung von Geschäftsprozessmodellen vereinfacht und den Grundstein für innovative Softwarewerkzeuge legt. KW - Abstraktion KW - Prozess KW - Modell KW - Transformation KW - Komplexität KW - abstraction KW - process KW - model KW - transformation KW - complexity Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-60258 ER - TY - THES A1 - Mahr, Philipp T1 - Resource efficient communication in network-based reconfigurable on-chip systems T1 - Ressourcen-effiziente Kommunikation in netzwerk-basierten, rekonfigurierbaren Systemen auf einem Chip N2 - The constantly growing capacity of reconfigurable devices allows simultaneous execution of complex applications on those devices. The mere diversity of applications deems it impossible to design an interconnection network matching the requirements of every possible application perfectly, leading to suboptimal performance in many cases. However, the architecture of the interconnection network is not the only aspect affecting performance of communication. The resource manager places applications on the device and therefore influences latency between communicating partners and overall network load. Communication protocols affect performance by introducing data and processing overhead putting higher load on the network and increasing resource demand. Approaching communication holistically not only considers the architecture of the interconnect, but communication-aware resource management, communication protocols and resource usage just as well. Incorporation of different parts of a reconfigurable system during design- and runtime and optimizing them with respect to communication demand results in more resource efficient communication. Extensive evaluation shows enhanced performance and flexibility, if communication on reconfigurable devices is regarded in a holistic fashion. N2 - Die Leistungsfähigkeit rekonfigurierbarer Rechensysteme steigt kontinuierlich und ermöglicht damit die parallele Ausführung von immer mehr und immer größeren Anwendungen. Die Vielfalt an Anwendungen macht es allerdings unmöglich ein optimales Kommunikationsnetzwerk zu entwickeln, welches die Anforderung jeder denkbaren Anwendung berücksichtigt. Die Performanz des rekonfigurierbaren Rechensystems sinkt. Das Kommunikationsnetzwerk ist jedoch nicht der einzige Teil des Systems, der Einfluss auf die Kommunikation- sperformanz nimmt. Die Ressourcenverwaltung des Systems beeinflusst durch die Platzierung der Anwendungen die Latenz zwischen Kommunikationspartnern und die Kommunikationslast im Netzwerk. Kommunikationsprotokolle beeinträchtigen die Performanz der Kommunikation durch Daten und Rechen- overhead, die ebenso zu erhöhter Netzwerklast sowie Ressourcenanforderungen führen. In einem ganzheitlichen Kommunikationsansatz wird nicht nur das Kommunikationsnetzwerk berücksichtigt, sondern außerdem Ressourcenverwaltung, Kommunikationsprotokolle und die anderweitige Verwendung vorhandener, temporär ungenutzter Kommunikationsressourcen. Durch Einbeziehung dieser Aspekte während Entwurfs- und Laufzeit und durch Optimierung unter Berücksichtigung der Kommunikationsanforderungen, wird eine ressourceneneffizien tere Kommunikation erreicht. Ausführliche Evaluationen zeigen, dass eine ganzheitliche Betrachtung von Kommunikationsfaktoren, Verbesserungen von Performanz und Flexibilität erzielt. KW - Rekonfiguration KW - Platzierung KW - Netzwerke KW - Kommunikation KW - reconfiguration KW - networks-on-chip KW - communication KW - placement KW - scheduling Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-59914 ER - TY - THES A1 - Gebser, Martin T1 - Proof theory and algorithms for answer set programming T1 - Beweistheorie und Algorithmen für die Antwortmengenprogrammierung N2 - Answer Set Programming (ASP) is an emerging paradigm for declarative programming, in which a computational problem is specified by a logic program such that particular models, called answer sets, match solutions. ASP faces a growing range of applications, demanding for high-performance tools able to solve complex problems. ASP integrates ideas from a variety of neighboring fields. In particular, automated techniques to search for answer sets are inspired by Boolean Satisfiability (SAT) solving approaches. While the latter have firm proof-theoretic foundations, ASP lacks formal frameworks for characterizing and comparing solving methods. Furthermore, sophisticated search patterns of modern SAT solvers, successfully applied in areas like, e.g., model checking and verification, are not yet established in ASP solving. We address these deficiencies by, for one, providing proof-theoretic frameworks that allow for characterizing, comparing, and analyzing approaches to answer set computation. For another, we devise modern ASP solving algorithms that integrate and extend state-of-the-art techniques for Boolean constraint solving. We thus contribute to the understanding of existing ASP solving approaches and their interconnections as well as to their enhancement by incorporating sophisticated search patterns. The central idea of our approach is to identify atomic as well as composite constituents of a propositional logic program with Boolean variables. This enables us to describe fundamental inference steps, and to selectively combine them in proof-theoretic characterizations of various ASP solving methods. In particular, we show that different concepts of case analyses applied by existing ASP solvers implicate mutual exponential separations regarding their best-case complexities. We also develop a generic proof-theoretic framework amenable to language extensions, and we point out that exponential separations can likewise be obtained due to case analyses on them. We further exploit fundamental inference steps to derive Boolean constraints characterizing answer sets. They enable the conception of ASP solving algorithms including search patterns of modern SAT solvers, while also allowing for direct technology transfers between the areas of ASP and SAT solving. Beyond the search for one answer set of a logic program, we address the enumeration of answer sets and their projections to a subvocabulary, respectively. The algorithms we develop enable repetition-free enumeration in polynomial space without being intrusive, i.e., they do not necessitate any modifications of computations before an answer set is found. Our approach to ASP solving is implemented in clasp, a state-of-the-art Boolean constraint solver that has successfully participated in recent solver competitions. Although we do here not address the implementation techniques of clasp or all of its features, we present the principles of its success in the context of ASP solving. N2 - Antwortmengenprogrammierung (engl. Answer Set Programming; ASP) ist ein Paradigma zum deklarativen Problemlösen, wobei Problemstellungen durch logische Programme beschrieben werden, sodass bestimmte Modelle, Antwortmengen genannt, zu Lösungen korrespondieren. Die zunehmenden praktischen Anwendungen von ASP verlangen nach performanten Werkzeugen zum Lösen komplexer Problemstellungen. ASP integriert diverse Konzepte aus verwandten Bereichen. Insbesondere sind automatisierte Techniken für die Suche nach Antwortmengen durch Verfahren zum Lösen des aussagenlogischen Erfüllbarkeitsproblems (engl. Boolean Satisfiability; SAT) inspiriert. Letztere beruhen auf soliden beweistheoretischen Grundlagen, wohingegen es für ASP kaum formale Systeme gibt, um Lösungsmethoden einheitlich zu beschreiben und miteinander zu vergleichen. Weiterhin basiert der Erfolg moderner Verfahren zum Lösen von SAT entscheidend auf fortgeschrittenen Suchtechniken, die in gängigen Methoden zur Antwortmengenberechnung nicht etabliert sind. Diese Arbeit entwickelt beweistheoretische Grundlagen und fortgeschrittene Suchtechniken im Kontext der Antwortmengenberechnung. Unsere formalen Beweissysteme ermöglichen die Charakterisierung, den Vergleich und die Analyse vorhandener Lösungsmethoden für ASP. Außerdem entwerfen wir moderne Verfahren zum Lösen von ASP, die fortgeschrittene Suchtechniken aus dem SAT-Bereich integrieren und erweitern. Damit trägt diese Arbeit sowohl zum tieferen Verständnis von Lösungsmethoden für ASP und ihrer Beziehungen untereinander als auch zu ihrer Verbesserung durch die Erschließung fortgeschrittener Suchtechniken bei. Die zentrale Idee unseres Ansatzes besteht darin, Atome und komposite Konstrukte innerhalb von logischen Programmen gleichermaßen mit aussagenlogischen Variablen zu assoziieren. Dies ermöglicht die Isolierung fundamentaler Inferenzschritte, die wir in formalen Charakterisierungen von Lösungsmethoden für ASP selektiv miteinander kombinieren können. Darauf aufbauend zeigen wir, dass unterschiedliche Einschränkungen von Fallunterscheidungen zwangsläufig zu exponentiellen Effizienzunterschieden zwischen den charakterisierten Methoden führen. Wir generalisieren unseren beweistheoretischen Ansatz auf logische Programme mit erweiterten Sprachkonstrukten und weisen analytisch nach, dass das Treffen bzw. Unterlassen von Fallunterscheidungen auf solchen Konstrukten ebenfalls exponentielle Effizienzunterschiede bedingen kann. Die zuvor beschriebenen fundamentalen Inferenzschritte nutzen wir zur Extraktion inhärenter Bedingungen, denen Antwortmengen genügen müssen. Damit schaffen wir eine Grundlage für den Entwurf moderner Lösungsmethoden für ASP, die fortgeschrittene, ursprünglich für SAT konzipierte, Suchtechniken mit einschließen und darüber hinaus einen transparenten Technologietransfer zwischen Verfahren zum Lösen von ASP und SAT erlauben. Neben der Suche nach einer Antwortmenge behandeln wir ihre Aufzählung, sowohl für gesamte Antwortmengen als auch für Projektionen auf ein Subvokabular. Hierfür entwickeln wir neuartige Methoden, die wiederholungsfreies Aufzählen in polynomiellem Platz ermöglichen, ohne die Suche zu beeinflussen und ggf. zu behindern, bevor Antwortmengen berechnet wurden. KW - Wissensrepräsentation und -verarbeitung KW - Antwortmengenprogrammierung KW - Beweistheorie KW - Algorithmen KW - Knowledge Representation and Reasoning KW - Answer Set Programming KW - Proof Theory KW - Algorithms Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-55425 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 - THES A1 - Albrecht, Alexander T1 - Understanding and managing extract-transform-load systems Y1 - 2013 ER - TY - THES A1 - Kaufmann, Benjamin T1 - High performance answer set solving Y1 - 2015 ER - TY - BOOK A1 - Plattner, Hasso A1 - Leukert, Bernd T1 - The in-memory revolution BT - how sap hana enables business of the future N2 - 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. Y1 - 2015 SN - 978-3-319-16672-8 PB - Springer CY - Cham 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 - Lindauer, Marius A1 - Hoos, Holger H. A1 - Hutter, Frank A1 - Schaub, Torsten H. 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 - 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 - Hoos, Holger A1 - Kaminski, Roland A1 - Lindauer, Marius A1 - Schaub, Torsten H. 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 - Anger, Christian A1 - Konczak, Kathrin A1 - Linke, Thomas T1 - NoMoRe: Non-monotonic reasoning with logic programs Y1 - 2002 SN - 3-540-44190-5 ER - TY - JOUR A1 - Linke, Thomas A1 - Anger, Christian A1 - Konczak, Kathrin T1 - More on nomore Y1 - 2002 ER - TY - BOOK A1 - Aydin, Suna A1 - Jürgensen, Helmut A1 - Robbins, L. E. T1 - Dialogues as co-operating grammars T3 - Preprint / Universität Potsdam, Institut für Informatik Y1 - 2001 SN - 0946-7580 VL - 2001, 1 PB - Univ. CY - Potsdam ER - TY - JOUR A1 - Wang, Kewen T1 - A comparative study of disjunctive well-founded semantics Y1 - 2001 SN - 3-540-42593-4 ER - TY - BOOK ED - Benferhat, Salem ED - Besnard, Philippe T1 - Symbolic and quantitative approaches to reasoning with uncertainty : 6th European conference, ECSQARU 2001, Toulouse, France, September 19 - 21, 2001 ; proceedings T3 - Lecture notes in computer science Y1 - 2001 SN - 3-540-42464-4 U6 - https://doi.org/10.1007/3-540-44652-4 VL - 2143 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Schaub, Torsten H. A1 - Wang, Kewen T1 - A comparative study of logic programs with preference Y1 - 2001 ER - TY - JOUR A1 - Wang, Kewen T1 - Disjunctive well-founded semantics revisited Y1 - 2001 ER - TY - JOUR A1 - Wang, Kewen T1 - A top-down procedure for disjucntive well-founded semantics Y1 - 2001 ER - TY - JOUR A1 - Wang, Kewen A1 - Zhou, Lizhu T1 - An extension to GCWA and query evaluation for disjunctive deductive databases Y1 - 2001 ER - TY - JOUR A1 - Anger, Christian A1 - Konczak, Kathrin A1 - Linke, Thomas T1 - A system for non-monotonic reasoning under answer set semantics Y1 - 2001 SN - 3-540-42593-4 ER - TY - JOUR A1 - Besnard, Philippe A1 - Hunter, Anthony T1 - A logic-based theory of deductive arguments Y1 - 2001 SN - 0004-3702 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - How to reason credulously and skeptically within a single extension. Y1 - 2001 SN - 3-540- 42464-4 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - A generic compiler for ordered logic programs Y1 - 2001 SN - 3-540-42593-4 ER - TY - JOUR A1 - Linke, Thomas T1 - Graph theoretical characterization and computation of answer sets Y1 - 2001 SN - 1-558-60777-3 SN - 1045-0823 ER - TY - JOUR A1 - Schaub, Torsten H. A1 - Wang, Kewen T1 - A comparative study of logic programs with preference Y1 - 2001 SN - 1-558-60777-3 SN - 1045-0823 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - How to reason credulously and skeptically within a single extension Y1 - 2001 ER - TY - JOUR A1 - Wang, Kewen T1 - A top-down procedure for disjucntive well-founded semantics Y1 - 2001 SN - 3-540-42254-4 ER - TY - JOUR A1 - Linke, Thomas T1 - Graph theoretical characterization and computation of answer sets Y1 - 2001 ER - TY - BOOK ED - Brewka, Gerhard ED - Witteveen, Cees ED - Schaub, Torsten H. T1 - Proceedings of the Fifth Dutch German Workshop on Nonmonotonic Reasoning Techniques and their Applications, DGNMR'2001, Potsdam, 4. - 6. April 2001 Y1 - 2001 CY - Potsdam ER - TY - JOUR A1 - Kose, F. A1 - Weckwerth, Wolfram A1 - Linke, Thomas A1 - Fiehn, Oliver T1 - Visualizing plant metabolomic correlation networks using clique-metabolite matrices Y1 - 2001 ER - TY - THES A1 - Huong, Dinh Thi Thanh T1 - Correctness proofs and probabilistic tests for constructive specifications and functional programs Y1 - 2001 ER - TY - JOUR A1 - Reinke, Thomas T1 - Architecture-based construction of multiagent systems Y1 - 2000 SN - 1-58603-013-2 ER - TY - JOUR A1 - Zien, Alexander A1 - Rätsch, Gunnar A1 - Mika, Sebastian A1 - Schölkopf, Bernhard A1 - Lengauer, Thomas A1 - Müller, Klaus-Robert T1 - Engineering support vector machine kernels that recognize translation initiation sites Y1 - 2000 SN - 1367-4803 ER - TY - JOUR A1 - Wübbeler, G. A1 - Ziehe, Andreas A1 - Mackert, B.-M. A1 - Müller, Klaus-Robert A1 - Trahms, L. A1 - Curio, Gabriel T1 - Independent component analysis of noninvasively recorded cortical magnetic DC-fields in humans Y1 - 2000 ER - TY - BOOK A1 - Tepoyan, Liparit T1 - Degenerated operator equations og higher order T3 - Preprint / Universität Potsdam, Institut für Mathematik, Arbeitsgruppe Partiell Y1 - 2000 SN - 1437-739X PB - Univ. CY - Potsdam ER - TY - JOUR A1 - Ziehe, Andreas A1 - Müller, Klaus-Robert A1 - Nolte, G. A1 - Mackert, B.-M. A1 - Curio, Gabriel T1 - Artifact reduction in magnetoneurography based on time-delayed second-order correlations Y1 - 2000 ER - TY - BOOK A1 - Coriasco, S. A1 - Panarese, P. T1 - Fourier integral operators defined by classical symbols with exit behaviour T3 - Preprint / Universität Potsdam, Institut für Mathematik, Arbeitsgruppe Partiell Y1 - 2000 SN - 1437-739X PB - Univ. CY - Potsdam ER - TY - JOUR A1 - Rätsch, Gunnar A1 - Schölkopf, B. A1 - Smola, Alexander J. A1 - Mika, Sebastian A1 - Onoda, T. A1 - Müller, Klaus-Robert T1 - Robust ensemble learning Y1 - 2000 SN - 0-262-19448-1 ER - TY - BOOK ED - Solla, Sara A. ED - Müller, Klaus-Robert T1 - Advances in neural information processing systems 12 : proceedings of the 1999 conference Y1 - 2000 SN - 0-262-19450-3 PB - MIT Press CY - Cambridge, Mass. ER - TY - BOOK A1 - Rätsch, Gunnar A1 - Schölkopf, B. A1 - Mika, Sebastian A1 - Müller, Klaus-Robert T1 - SVM and boosting : one class T3 - GMD-Report Y1 - 2000 VL - 119 PB - GMD-Forschungszentrum Informationstechnik CY - Sankt Augustin ER - TY - BOOK A1 - Tsuda, Koji A1 - Sugiyama, Masashi A1 - Müller, Klaus-Robert T1 - Subspace information criterion for non-quadratice regularizers : model selection for sparse regressors T3 - GMD-Report Y1 - 2000 VL - 120 PB - GMD-Forschungszentrum Informationstechnik CY - Sankt Augustin ER - TY - JOUR A1 - Rätsch, Gunnar A1 - Schölkopf, B. A1 - Smola, Alexander J. A1 - Müller, Klaus-Robert A1 - Mika, Sebastian T1 - V-Arc : ensemble learning in the preence of outliers Y1 - 2000 ER - TY - JOUR A1 - Parra, L. A1 - Spence, C. A1 - Sajda, P. A1 - Ziehe, Andreas A1 - Müller, Klaus-Robert T1 - Unmixing hyperspectral data Y1 - 2000 ER - TY - JOUR A1 - Kohlmorgen, J. A1 - Müller, Klaus-Robert A1 - Rittweger, J. A1 - Pawelzik, K. T1 - Identification of nonstationary dynamics in physiological recordings Y1 - 2000 ER - TY - JOUR A1 - Mika, Sebastian A1 - Rätsch, Gunnar A1 - Weston, J. A1 - Schölkopf, B. A1 - Smola, Alexander J. A1 - Müller, Klaus-Robert T1 - Invariant feature extraction and classification in kernel spaces Y1 - 2000 ER - TY - JOUR A1 - Onoda, T. A1 - Rätsch, Gunnar A1 - Müller, Klaus-Robert T1 - An asymptotic analysis and improvement of AdaBoost in the binary classification case (in Japanese) Y1 - 2000 ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten H. T1 - Significant inferences Y1 - 2000 SN - 1-55860-690-4 ER - TY - JOUR A1 - Linke, Thomas A1 - Schaub, Torsten H. T1 - Alternative foundations for Reiter's default logic. Y1 - 2000 SN - 0004-3702 ER - TY - BOOK A1 - Linke, Thomas T1 - New foundations for automation of default reasoning Y1 - 2000 SN - 3-89838-237-0 VL - 237 PB - Akad. Verl.-Ges. Aka CY - Berlin ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten H. T1 - What is a (non-constructive) non-monotone logical system? Y1 - 2000 SN - 0304-3975 ER - TY - JOUR A1 - Besnard, Philippe A1 - Lang, Jerome T1 - Graded paraconsistency Y1 - 2000 SN - 0-86380-253-2 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - The role of default logic in knowledge representation Y1 - 2000 SN - 0-7923-7224-7 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - Expressing preferences in default logic Y1 - 2000 SN - 0004-3702 ER - TY - JOUR A1 - Wong, P. A1 - Besnard, Philippe T1 - Paraconsistent reasoning as an analytical tool Y1 - 2000 SN - 1367-0751 ER - TY - JOUR A1 - Wang, Kewen T1 - Argumentation-based abduction in disjunctive logic programming Y1 - 2000 ER - TY - JOUR A1 - Besnard, Philippe A1 - Hunter, Anthony T1 - Towards a logic-based theory of argumentation Y1 - 2000 SN - 0-262-51112-6 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - A compilation of Brewka and Eiter's approach to prioritizationtion Y1 - 2000 SN - 3-540-41131-3 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - A consistency-based model for belief change: preliminary report Y1 - 2000 SN - 0-262-51112-6 ER - TY - JOUR A1 - Wang, Kewen A1 - Zhou, Lizhu A1 - Lin, Fangzhen T1 - Alternating fixpoint theory for logic programs with priority Y1 - 2000 SN - 3-540-67797-6 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - Logic programs with compiled preferences Y1 - 2000 SN - 1-58603-013-2 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - Logic programs with compiled preferences Y1 - 2000 UR - http://xxx.lanl.gov/abs/cs.AI/0003028 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - A consistency-based model for belief change: preliminary report Y1 - 2000 UR - http://xxx.lanl.gov/abs/cs.AI/0003052 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - A compiler for ordered logic programs Y1 - 2000 UR - http://arxiv.org/abs/cs.AI/0003024 ER - TY - JOUR A1 - Brüning, Stefan A1 - Schaub, Torsten H. T1 - A connection calculus for handling incomplete information Y1 - 2000 ER - TY - JOUR A1 - Horn, Erika A1 - Kupries, Mario A1 - Reinke, Thomas T1 - Properties and models of software agents and prefabrication for agent application systems Y1 - 1999 SN - 0-7695-0001-3 , 0-7695-0002-1 , 0-7695-0003-X ER -