TY - BOOK A1 - Schaub, Torsten T1 - The automation of reasoning with incomplete information : from semantic foundations to efficient computation T3 - Lecture notes in computer science Y1 - 1999 SN - 3-540-64515-2 U6 - https://doi.org/10.1007/BFb0054963 VL - 1409 PB - Springer CY - Berlin ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten T1 - Signed systems for paraconsistent reasoning Y1 - 1998 ER - TY - JOUR A1 - Brain, Martin A1 - Gebser, Martin A1 - Pührer, Jörg A1 - Schaub, Torsten A1 - Tompits, Hans A1 - Woltran, Stefan T1 - "That is illogical, Captain!" : the debugging support tool spock for answer-set programs ; system description Y1 - 2007 ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Neumann, André A1 - Schaub, Torsten T1 - Conflict-driven answer set enumeration Y1 - 2007 SN - 978-3-540- 72199-4 ER - TY - JOUR A1 - Linke, Thomas A1 - Schaub, Torsten T1 - Putting default logics in perspective Y1 - 1996 SN - 3-540-61708-6 ER - TY - JOUR A1 - Linke, Thomas A1 - Schaub, Torsten T1 - Lemma handling in default logic theorem provers Y1 - 1995 SN - 3540601120 ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Neumann, André A1 - Schaub, Torsten T1 - Conflict-driven answer set solving Y1 - 2007 SN - 978-1-57735-323-2 ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten T1 - A context-based framework for default logics Y1 - 1993 SN - 0-262-51071-5 ER - TY - JOUR A1 - Gebser, Martin A1 - Gharib, Mona A1 - Schaub, Torsten T1 - Incremental answer sets and their computation Y1 - 2007 ER - TY - JOUR A1 - Gebser, Martin A1 - Schaub, Torsten T1 - Generic tableaux for answer set programming Y1 - 2007 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten T1 - A consistency-based framework for merging knowledge bases Y1 - 2007 SN - 1570-8683 ER - TY - JOUR A1 - Konczak, Kathrin A1 - Linke, Thomas A1 - Schaub, Torsten T1 - Graphs and colorings for answer set programming N2 - We investigate the usage of rule dependency graphs and their colorings for characterizing and computing answer sets of logic programs. This approach provides us with insights into the interplay between rules when inducing answer sets. We start with different characterizations of answer sets in terms of totally colored dependency graphs that differ ill graph-theoretical aspects. We then develop a series of operational characterizations of answer sets in terms of operators on partial colorings. In analogy to the notion of a derivation in proof theory, our operational characterizations are expressed as (non-deterministically formed) sequences of colorings, turning an uncolored graph into a totally colored one. In this way, we obtain an operational framework in which different combinations of operators result in different formal properties. Among others, we identify the basic strategy employed by the noMoRe system and justify its algorithmic approach. Furthermore, we distinguish operations corresponding to Fitting's operator as well as to well-founded semantics Y1 - 2006 UR - http://www.cs.kuleuven.ac.be/~dtai/projects/ALP//TPLP/ U6 - https://doi.org/10.1017/S1471068405002528 SN - 1471-0684 ER - TY - JOUR A1 - Gressmann, Jean A1 - Janhunen, Tomi A1 - Mercer, Robert E. A1 - Schaub, Torsten A1 - Thiele, Sven A1 - Tichy, Richard T1 - On probing and multi-threading in platypus Y1 - 2006 UR - http://www2.in.tu-clausthal.de/~tmbehrens/NMR_Proc_TR4.pdf ER - TY - JOUR A1 - Anger, Christian A1 - Gebser, Martin A1 - Linke, Thomas A1 - Neumann, Andre A1 - Schaub, Torsten T1 - The nomore++ approach to answer set solving Y1 - 2005 UR - http://www.cs.uni-potsdam.de/wv/pdfformat/angelinesc05c.pdf ER - TY - JOUR A1 - Gressmann, Jean A1 - Janhunen, Tomi A1 - Mercer, Robert E. A1 - Schaub, Torsten A1 - Thiele, Sven A1 - Tichy, Richard T1 - Platypus : a platform for distributed answer set solving Y1 - 2005 UR - http://www.cs.uni-potsdam.de/wv/pdfformat/grjamescthti05a.pdf ER - TY - JOUR A1 - Sarsakov, Vladimir A1 - Schaub, Torsten A1 - Tompits, Hans A1 - Woltran, Stefan T1 - A compiler for nested logic programming Y1 - 2004 SN - 3-540- 20721-x ER - TY - JOUR A1 - Gebser, Martin A1 - Liu, Lengning A1 - Namasivayam, Gayathri A1 - Neumann, André A1 - Schaub, Torsten A1 - Truszczynski, Miroslaw T1 - The first answer set programming system competition Y1 - 2007 SN - 978-3-540- 72199-4 ER - TY - JOUR A1 - Anger, Christian A1 - Gebser, Martin A1 - Linke, Thomas A1 - Neumann, Andre A1 - Schaub, Torsten T1 - The nomore++ approach to answer set solving Y1 - 2005 UR - http://www.cs.uni-potsdam.de/wv/pdfformat/angelinesc05c.pdf ER - TY - JOUR A1 - Anger, Christian A1 - Konczak, Kathrin A1 - Linke, Thomas A1 - Schaub, Torsten T1 - A Glimpse of Answer Set Programming Y1 - 2005 UR - http://www.cs.uni-potsdam.de/~konczak/Papers/ankolisc05.pdf SN - 0170-4516 ER - TY - JOUR A1 - Grell, Susanne A1 - Konczak, Kathrin A1 - Schaub, Torsten T1 - nomore) : a system for computing preferred Answer Sets Y1 - 2005 SN - 0302-9743 ER - TY - JOUR A1 - Konczak, Kathrin A1 - Schaub, Torsten A1 - Linke, Thomas T1 - Graphs and colorings for answer set programming with preferences N2 - The integration of preferences into answer set programming constitutes an important practical device for distinguishing certain preferred answer sets from non-preferred ones. To this end, we elaborate upon rule dependency graphs and their colorings for characterizing different preference handling strategies found in the literature. We start from a characterization of (three types of) preferred answer sets in terms of totally colored dependency graphs. In particular, we demonstrate that this approach allows us to capture all three approaches to preferences in a uniform setting by means of the concept of a height function. In turn, we exemplarily develop an operational characterization of preferred answer sets in terms of operators on partial colorings for one particular strategy. In analogy to the notion of a derivation in proof theory, our operational characterization is expressed as a (non-deterministically formed) sequence of colorings, gradually turning an uncolored graph into a totally colored one Y1 - 2003 SN - 0169-2968 ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten A1 - Tompits, Hans A1 - Woltran, Stefan T1 - Paraconsistent reasoning via quantified boolean formulas : Part II: Circumscribing inconsistent theories Y1 - 2003 SN - 3-540- 409494-5 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Hunter, Anthony A1 - Schaub, Torsten T1 - COBA: a consistency-based belief revision system Y1 - 2002 SN - 3-540-44190-5 ER - TY - JOUR A1 - Flöter, André A1 - Nicolas, Jacques A1 - Schaub, Torsten A1 - Selbig, Joachim T1 - Threshold extraction in metabolite concentration data Y1 - 2003 UR - http://www.cs.uni-potsdam.de/wv/pdfformat/floeterGCB2003.pdf ER - TY - JOUR A1 - Schaub, Torsten A1 - Wang, T. T1 - Preferred well-founded semantics for logic programming by alternating fixpoints : preliminary report Y1 - 2002 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten T1 - A concictency-based paradigm for belief change Y1 - 2003 SN - 0004-3702 ER - TY - JOUR A1 - Besnard, Philippe A1 - Fanselow, Gisbert A1 - Schaub, Torsten T1 - Optimality theory as a family of cumulative logics Y1 - 2002 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten T1 - Reasoning credulously and skeptically within a single extension Y1 - 2002 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten 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 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 T1 - A consistency-based model for belief change: preliminary report Y1 - 2000 SN - 0-262-51112-6 ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten T1 - Significant inferences Y1 - 2000 SN - 1-55860-690-4 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten 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 A1 - Tompits, Hans T1 - A compiler for ordered logic programs Y1 - 2000 UR - http://arxiv.org/abs/cs.AI/0003024 ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten T1 - What is a (non-constructive) non-monotone logical system? Y1 - 2000 SN - 0304-3975 ER - TY - JOUR A1 - Brüning, Stefan A1 - Schaub, Torsten T1 - A connection calculus for handling incomplete information Y1 - 2000 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten T1 - Expressing preferences in default logic Y1 - 2000 SN - 0004-3702 ER - TY - JOUR A1 - Schaub, Torsten A1 - Nicolas, Pascal T1 - An implementation platform for query-answering in default logics : the XRay system, its implementation and evaluation Y1 - 1997 SN - 3-540-63255-7 ER - TY - JOUR A1 - Schaub, Torsten A1 - Nicolas, Pascal T1 - An implementation platform for query-answering in default logics : theoretical underpinnings Y1 - 1997 SN - 3-540-63614-5 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten T1 - Compiling reasoning with and about preferences into default logic Y1 - 1997 SN - 1-558-60480-4 SN - 1045-0823 ER - TY - JOUR A1 - Schaub, Torsten A1 - Thielscher, Michael T1 - Skeptical query-answering in constrained default logic Y1 - 1996 SN - 3-540-61313-7 ER - TY - JOUR A1 - Brüning, Stefan A1 - Schaub, Torsten T1 - A model-based approach to consistency-checking Y1 - 1996 SN - 3-540-61286-6 ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten T1 - Circumscribing inconsistency Y1 - 1997 SN - 1-558-60480-4 SN - 1045-0823 ER - TY - JOUR A1 - Schaub, Torsten A1 - Brüning, Stefan T1 - Prolog technology for default reasoning Y1 - 1996 SN - 0-471-96809-9 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten T1 - Compiling specificity into approaches to nonmonotonic reasoning Y1 - 1997 SN - 0004-3702 ER - TY - JOUR A1 - Linke, Thomas A1 - Schaub, Torsten T1 - Towards a classification of default logic Y1 - 1997 ER - TY - JOUR A1 - Videla, Santiago A1 - Guziolowski, Carito A1 - Eduati, Federica A1 - Thiele, Sven A1 - Gebser, Martin A1 - Nicolas, Jacques A1 - Saez-Rodriguez, Julio A1 - Schaub, Torsten A1 - Siegel, Anne T1 - Learning Boolean logic models of signaling networks with ASP JF - Theoretical computer science N2 - Boolean networks provide a simple yet powerful qualitative modeling approach in systems biology. However, manual identification of logic rules underlying the system being studied is in most cases out of reach. Therefore, automated inference of Boolean logical networks from experimental data is a fundamental question in this field. This paper addresses the problem consisting of learning from a prior knowledge network describing causal interactions and phosphorylation activities at a pseudo-steady state, Boolean logic models of immediate-early response in signaling transduction networks. The underlying optimization problem has been so far addressed through mathematical programming approaches and the use of dedicated genetic algorithms. In a recent work we have shown severe limitations of stochastic approaches in this domain and proposed to use Answer Set Programming (ASP), considering a simpler problem setting. Herein, we extend our previous work in order to consider more realistic biological conditions including numerical datasets, the presence of feedback-loops in the prior knowledge network and the necessity of multi-objective optimization. In order to cope with such extensions, we propose several discretization schemes and elaborate upon our previous ASP encoding. Towards real-world biological data, we evaluate the performance of our approach over in silico numerical datasets based on a real and large-scale prior knowledge network. The correctness of our encoding and discretization schemes are dealt with in Appendices A-B. (C) 2014 Elsevier B.V. All rights reserved. KW - Answer set programming KW - Signaling transduction networks KW - Boolean logic models KW - Combinatorial multi-objective optimization KW - Systems biology Y1 - 2015 U6 - https://doi.org/10.1016/j.tcs.2014.06.022 SN - 0304-3975 SN - 1879-2294 VL - 599 SP - 79 EP - 101 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hoos, Holger A1 - Kaminski, Roland A1 - Lindauer, Marius A1 - Schaub, Torsten T1 - aspeed: Solver scheduling via answer set programming JF - Theory and practice of logic programming N2 - Although Boolean Constraint Technology has made tremendous progress over the last decade, the efficacy of state-of-the-art solvers is known to vary considerably across different types of problem instances, and is known to depend strongly on algorithm parameters. This problem was addressed by means of a simple, yet effective approach using handmade, uniform, and unordered schedules of multiple solvers in ppfolio, which showed very impressive performance in the 2011 Satisfiability Testing (SAT) Competition. Inspired by this, we take advantage of the modeling and solving capacities of Answer Set Programming (ASP) to automatically determine more refined, that is, nonuniform and ordered solver schedules from the existing benchmarking data. We begin by formulating the determination of such schedules as multi-criteria optimization problems and provide corresponding ASP encodings. The resulting encodings are easily customizable for different settings, and the computation of optimum schedules can mostly be done in the blink of an eye, even when dealing with large runtime data sets stemming from many solvers on hundreds to thousands of instances. Also, the fact that our approach can be customized easily enabled us to swiftly adapt it to generate parallel schedules for multi-processor machines. KW - algorithm schedules KW - answer set programming KW - portfolio-based solving Y1 - 2015 U6 - https://doi.org/10.1017/S1471068414000015 SN - 1471-0684 SN - 1475-3081 VL - 15 SP - 117 EP - 142 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Kaminski, Roland A1 - Ostrowski, Max A1 - Schaub, Torsten 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 - Cabalar, Pedro A1 - Fandiño, Jorge A1 - Schaub, Torsten A1 - Schellhorn, Sebastian T1 - Gelfond-Zhang aggregates as propositional formulas JF - Artificial intelligence N2 - Answer Set Programming (ASP) has become a popular and widespread paradigm for practical Knowledge Representation thanks to its expressiveness and the available enhancements of its input language. One of such enhancements is the use of aggregates, for which different semantic proposals have been made. In this paper, we show that any ASP aggregate interpreted under Gelfond and Zhang's (GZ) semantics can be replaced (under strong equivalence) by a propositional formula. Restricted to the original GZ syntax, the resulting formula is reducible to a disjunction of conjunctions of literals but the formulation is still applicable even when the syntax is extended to allow for arbitrary formulas (including nested aggregates) in the condition. Once GZ-aggregates are represented as formulas, we establish a formal comparison (in terms of the logic of Here-and-There) to Ferraris' (F) aggregates, which are defined by a different formula translation involving nested implications. In particular, we prove that if we replace an F-aggregate by a GZ-aggregate in a rule head, we do not lose answer sets (although more can be gained). This extends the previously known result that the opposite happens in rule bodies, i.e., replacing a GZ-aggregate by an F-aggregate in the body may yield more answer sets. Finally, we characterize a class of aggregates for which GZ- and F-semantics coincide. KW - Aggregates KW - Answer Set Programming Y1 - 2019 U6 - https://doi.org/10.1016/j.artint.2018.10.007 SN - 0004-3702 SN - 1872-7921 VL - 274 SP - 26 EP - 43 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Videla, Santiago T1 - Reasoning on the response of logical signaling networks with answer set programming T1 - Modellierung Logischer Signalnetzwerke mittels Antwortmengenprogrammierung N2 - Deciphering the functioning of biological networks is one of the central tasks in systems biology. In particular, signal transduction networks are crucial for the understanding of the cellular response to external and internal perturbations. Importantly, in order to cope with the complexity of these networks, mathematical and computational modeling is required. We propose a computational modeling framework in order to achieve more robust discoveries in the context of logical signaling networks. More precisely, we focus on modeling the response of logical signaling networks by means of automated reasoning using Answer Set Programming (ASP). ASP provides a declarative language for modeling various knowledge representation and reasoning problems. Moreover, available ASP solvers provide several reasoning modes for assessing the multitude of answer sets. Therefore, leveraging its rich modeling language and its highly efficient solving capacities, we use ASP to address three challenging problems in the context of logical signaling networks: learning of (Boolean) logical networks, experimental design, and identification of intervention strategies. Overall, the contribution of this thesis is three-fold. Firstly, we introduce a mathematical framework for characterizing and reasoning on the response of logical signaling networks. Secondly, we contribute to a growing list of successful applications of ASP in systems biology. Thirdly, we present a software providing a complete pipeline for automated reasoning on the response of logical signaling networks. N2 - Deciphering the functioning of biological networks is one of the central tasks in systems biology. In particular, signal transduction networks are crucial for the understanding of the cellular response to external and internal perturbations. Importantly, in order to cope with the complexity of these networks, mathematical and computational modeling is required. We propose a computational modeling framework in order to achieve more robust discoveries in the context of logical signaling networks. More precisely, we focus on modeling the response of logical signaling networks by means of automated reasoning using Answer Set Programming (ASP). ASP provides a declarative language for modeling various knowledge representation and reasoning problems. Moreover, available ASP solvers provide several reasoning modes for assessing the multitude of answer sets. Therefore, leveraging its rich modeling language and its highly efficient solving capacities, we use ASP to address three challenging problems in the context of logical signaling networks: learning of (Boolean) logical networks, experimental design, and identification of intervention strategies. Overall, the contribution of this thesis is three-fold. Firstly, we introduce a mathematical framework for characterizing and reasoning on the response of logical signaling networks. Secondly, we contribute to a growing list of successful applications of ASP in systems biology. Thirdly, we present a software providing a complete pipeline for automated reasoning on the response of logical signaling networks. KW - Systembiologie KW - logische Signalnetzwerke KW - Antwortmengenprogrammierung KW - systems biology KW - logical signaling networks KW - answer set programming Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-71890 ER - TY - JOUR A1 - Dimopoulos, Yannis A1 - Gebser, Martin A1 - Lühne, Patrick A1 - Romero Davila, Javier A1 - Schaub, Torsten T1 - plasp 3 BT - Towards Effective ASP Planning JF - Theory and practice of logic programming N2 - We describe the new version of the Planning Domain Definition Language (PDDL)-to-Answer Set Programming (ASP) translator plasp. First, it widens the range of accepted PDDL features. Second, it contains novel planning encodings, some inspired by Satisfiability Testing (SAT) planning and others exploiting ASP features such as well-foundedness. All of them are designed for handling multivalued fluents in order to capture both PDDL as well as SAS planning formats. Third, enabled by multishot ASP solving, it offers advanced planning algorithms also borrowed from SAT planning. As a result, plasp provides us with an ASP-based framework for studying a variety of planning techniques in a uniform setting. Finally, we demonstrate in an empirical analysis that these techniques have a significant impact on the performance of ASP planning. KW - knowledge representation and nonmonotonic reasoning KW - technical notes and rapid communications KW - answer set programming KW - automated planning KW - action and change Y1 - 2019 U6 - https://doi.org/10.1017/S1471068418000583 SN - 1471-0684 SN - 1475-3081 VL - 19 IS - 3 SP - 477 EP - 504 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Kaminski, Roland A1 - Schaub, Torsten A1 - Siegel, Anne A1 - Videla, Santiago T1 - Minimal intervention strategies in logical signaling networks with ASP JF - Theory and practice of logic programming N2 - Proposing relevant perturbations to biological signaling networks is central to many problems in biology and medicine because it allows for enabling or disabling certain biological outcomes. In contrast to quantitative methods that permit fine-grained (kinetic) analysis, qualitative approaches allow for addressing large-scale networks. This is accomplished by more abstract representations such as logical networks. We elaborate upon such a qualitative approach aiming at the computation of minimal interventions in logical signaling networks relying on Kleene's three-valued logic and fixpoint semantics. We address this problem within answer set programming and show that it greatly outperforms previous work using dedicated algorithms. Y1 - 2013 U6 - https://doi.org/10.1017/S1471068413000422 SN - 1471-0684 VL - 13 SP - 675 EP - 690 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Schaub, Torsten A1 - Brüning, Stefan A1 - Nicolas, Pascal T1 - XRay : a prolog technology theorem prover for default reasoning: a system description Y1 - 1996 SN - 3-540-61511-3 ER - TY - JOUR A1 - Besnard, Philippe A1 - Schaub, Torsten T1 - A simple signed system for paraconsistent reasoning Y1 - 1996 SN - 3-540-61630-6 ER - TY - JOUR A1 - Gebser, Martin A1 - Schaub, Torsten A1 - Tompits, Hans A1 - Woltran, Stefan T1 - Alternative characterizations for program equivalence under aswer-set semantics : a preliminary report Y1 - 2007 ER - TY - THES A1 - Konczak, Kathrin T1 - Preferences in answer set programming T1 - Präferenzen in der Antwortmengenprogrammierung N2 - Answer Set Programming (ASP) emerged in the late 1990s as a new logic programming paradigm, having its roots in nonmonotonic reasoning, deductive databases, and logic programming with negation as failure. The basic idea of ASP is to represent a computational problem as a logic program whose answer sets correspond to solutions, and then to use an answer set solver for finding answer sets of the program. ASP is particularly suited for solving NP-complete search problems. Among these, we find applications to product configuration, diagnosis, and graph-theoretical problems, e.g. finding Hamiltonian cycles. On different lines of ASP research, many extensions of the basic formalism have been proposed. The most intensively studied one is the modelling of preferences in ASP. They constitute a natural and effective way of selecting preferred solutions among a plethora of solutions for a problem. For example, preferences have been successfully used for timetabling, auctioning, and product configuration. In this thesis, we concentrate on preferences within answer set programming. Among several formalisms and semantics for preference handling in ASP, we concentrate on ordered logic programs with the underlying D-, W-, and B-semantics. In this setting, preferences are defined among rules of a logic program. They select preferred answer sets among (standard) answer sets of the underlying logic program. Up to now, those preferred answer sets have been computed either via a compilation method or by meta-interpretation. Hence, the question comes up, whether and how preferences can be integrated into an existing ASP solver. To solve this question, we develop an operational graph-based framework for the computation of answer sets of logic programs. Then, we integrate preferences into this operational approach. We empirically observe that our integrative approach performs in most cases better than the compilation method or meta-interpretation. Another research issue in ASP are optimization methods that remove redundancies, as also found in database query optimizers. For these purposes, the rather recently suggested notion of strong equivalence for ASP can be used. If a program is strongly equivalent to a subprogram of itself, then one can always use the subprogram instead of the original program, a technique which serves as an effective optimization method. Up to now, strong equivalence has not been considered for logic programs with preferences. In this thesis, we tackle this issue and generalize the notion of strong equivalence to ordered logic programs. We give necessary and sufficient conditions for the strong equivalence of two ordered logic programs. Furthermore, we provide program transformations for ordered logic programs and show in how far preferences can be simplified. Finally, we present two new applications for preferences within answer set programming. First, we define new procedures for group decision making, which we apply to the problem of scheduling a group meeting. As a second new application, we reconstruct a linguistic problem appearing in German dialects within ASP. Regarding linguistic studies, there is an ongoing debate about how unique the rule systems of language are in human cognition. The reconstruction of grammatical regularities with tools from computer science has consequences for this debate: if grammars can be modelled this way, then they share core properties with other non-linguistic rule systems. N2 - Die Antwortmengenprogrammierung entwickelte sich in den späten 90er Jahren als neues Paradigma der logischen Programmierung und ist in den Gebieten des nicht-monotonen Schließens und der deduktiven Datenbanken verwurzelt. Dabei wird eine Problemstellung als logisches Programm repräsentiert, dessen Lösungen, die so genannten Antwortmengen, genau den Lösungen des ursprünglichen Problems entsprechen. Die Antwortmengenprogrammierung bildet ein geeignetes Fundament zur Repräsentation und zum Lösen von Entscheidungs- und Suchproblemen in der Komplexitätsklasse NP. Anwendungen finden wir unter anderem in der Produktkonfiguration, Diagnose und bei graphen-theoretischen Problemen, z.B. der Suche nach Hamiltonschen Kreisen. In den letzten Jahren wurden viele Erweiterungen der Antwortmengenprogrammierung betrachtet. Die am meisten untersuchte Erweiterung ist die Modellierung von Präferenzen. Diese bilden eine natürliche und effektive Möglichkeit, unter einer Vielzahl von Lösungen eines Problems bevorzugte Lösungen zu selektieren. Präferenzen finden beispielsweise in der Stundenplanung, bei Auktionen und bei Produktkonfigurationen ihre Anwendung. Der Schwerpunkt dieser Arbeit liegt in der Modellierung, Implementierung und Anwendung von Präferenzen in der Antwortmengenprogrammierung. Da es verschiedene Ansätze gibt, um Präferenzen darzustellen, konzentrieren wir uns auf geordnete logische Programme, wobei Präferenzen als partielle Ordnung der Regeln eines logischen Programms ausgedrückt werden. Dabei betrachten wir drei verschiedene Semantiken zur Interpretation dieser Präferenzen. Im Vorfeld wurden für diese Semantiken die bevorzugten Antwortmengen durch einen Compiler oder durch Meta-Interpretation berechnet. Da Präferenzen Lösungen selektieren, stellt sich die Frage, ob es möglich ist, diese direkt in den Berechnungsprozeß von präferenzierten Antwortmengen zu integrieren, so dass die bevorzugten Antwortmengen ohne Zwischenschritte berechnet werden können. Dazu entwickeln wir zuerst ein auf Graphen basierendes Gerüst zur Berechnung von Antwortmengen. Anschließend werden wir darin Präferenzen integrieren, so dass bevorzugte Antwortmengen ohne Compiler oder Meta-Interpretation berechnet werden. Es stellt sich heraus, dass die integrative Methode auf den meisten betrachteten Problemklassen wesentlich leistungsfähiger ist als der Compiler oder Meta-Interpretation. Ein weiterer Schwerpunkt dieser Arbeit liegt in der Frage, inwieweit sich geordnete logische Programme vereinfachen lassen. Dazu steht die Methodik der strengen Äquivalenz von logischen Programmen zur Verfügung. Wenn ein logisches Programm streng äquivalent zu einem seiner Teilprogramme ist, so kann man dieses durch das entsprechende Teilprogramm ersetzen, ohne dass sich die zugrunde liegende Semantik ändert. Bisher wurden strenge Äquivalenzen nicht für logische Programme mit Präferenzen untersucht. In dieser Arbeit definieren wir erstmalig strenge Äquivalenzen für geordnete logische Programme. Wir geben notwendige und hinreichende Bedingungen für die strenge Äquivalenz zweier geordneter logischer Programme an. Des Weiteren werden wir auch die Frage beantworten, inwieweit geordnete logische Programme und deren Präferenzstrukturen vereinfacht werden können. Abschließend präsentieren wir zwei neue Anwendungsbereiche von Präferenzen in der Antwortmengenprogrammierung. Zuerst definieren wir neue Prozeduren zur Entscheidungsfindung innerhalb von Gruppenprozessen. Diese integrieren wir anschließend in das Problem der Planung eines Treffens für eine Gruppe. Als zweite neue Anwendung rekonstruieren wir mit Hilfe der Antwortmengenprogrammierung eine linguistische Problemstellung, die in deutschen Dialekten auftritt. Momentan wird im Bereich der Linguistik darüber diskutiert, ob Regelsysteme von (menschlichen) Sprachen einzigartig sind oder nicht. Die Rekonstruktion von grammatikalischen Regularitäten mit Werkzeugen aus der Informatik erlaubt die Unterstützung der These, dass linguistische Regelsysteme Gemeinsamkeiten zu anderen nicht-linguistischen Regelsystemen besitzen. KW - Präferenzen KW - Antwortmengenprogrammierung KW - logische Programmierung KW - Künstliche Intelligenz KW - preferences KW - priorities KW - answer set programming KW - logic programming KW - artificial intelligence Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12058 ER - TY - JOUR A1 - Gebser, Martin A1 - Obermeier, Philipp A1 - Schaub, Torsten A1 - Ratsch-Heitmann, Michel A1 - Runge, Mario T1 - Routing driverless transport vehicles in car assembly with answer set programming JF - Theory and practice of logic programming N2 - Automated storage and retrieval systems are principal components of modern production and warehouse facilities. In particular, automated guided vehicles nowadays substitute human-operated pallet trucks in transporting production materials between storage locations and assembly stations. While low-level control systems take care of navigating such driverless vehicles along programmed routes and avoid collisions even under unforeseen circumstances, in the common case of multiple vehicles sharing the same operation area, the problem remains how to set up routes such that a collection of transport tasks is accomplished most effectively. We address this prevalent problem in the context of car assembly at Mercedes-Benz Ludwigsfelde GmbH, a large-scale producer of commercial vehicles, where routes for automated guided vehicles used in the production process have traditionally been hand-coded by human engineers. Such adhoc methods may suffice as long as a running production process remains in place, while any change in the factory layout or production targets necessitates tedious manual reconfiguration, not to mention the missing portability between different production plants. Unlike this, we propose a declarative approach based on Answer Set Programming to optimize the routes taken by automated guided vehicles for accomplishing transport tasks. The advantages include a transparent and executable problem formalization, provable optimality of routes relative to objective criteria, as well as elaboration tolerance towards particular factory layouts and production targets. Moreover, we demonstrate that our approach is efficient enough to deal with the transport tasks evolving in realistic production processes at the car factory of Mercedes-Benz Ludwigsfelde GmbH. KW - automated guided vehicle routing KW - car assembly operations KW - answer set programming Y1 - 2018 U6 - https://doi.org/10.1017/S1471068418000182 SN - 1471-0684 SN - 1475-3081 VL - 18 IS - 3-4 SP - 520 EP - 534 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Lindauer, Marius A1 - Hoos, Holger A1 - Leyton-Brown, Kevin A1 - Schaub, Torsten T1 - Automatic construction of parallel portfolios via algorithm configuration JF - Artificial intelligence N2 - Since 2004, increases in computational power described by Moore's law have substantially been realized in the form of additional cores rather than through faster clock speeds. To make effective use of modern hardware when solving hard computational problems, it is therefore necessary to employ parallel solution strategies. In this work, we demonstrate how effective parallel solvers for propositional satisfiability (SAT), one of the most widely studied NP-complete problems, can be produced automatically from any existing sequential, highly parametric SAT solver. Our Automatic Construction of Parallel Portfolios (ACPP) approach uses an automatic algorithm configuration procedure to identify a set of configurations that perform well when executed in parallel. Applied to two prominent SAT solvers, Lingeling and clasp, our ACPP procedure identified 8-core solvers that significantly outperformed their sequential counterparts on a diverse set of instances from the application and hard combinatorial category of the 2012 SAT Challenge. We further extended our ACPP approach to produce parallel portfolio solvers consisting of several different solvers by combining their configuration spaces. Applied to the component solvers of the 2012 SAT Challenge gold medal winning SAT Solver pfolioUZK, our ACPP procedures produced a significantly better-performing parallel SAT solver. KW - Algorithm configuration KW - Parallel SAT solving KW - Algorithm portfolios KW - Programming by optimization KW - Automated parallelization Y1 - 2016 U6 - https://doi.org/10.1016/j.artint.2016.05.004 SN - 0004-3702 SN - 1872-7921 VL - 244 SP - 272 EP - 290 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Schaub, Torsten 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 - Besnard, Philippe A1 - Schaub, Torsten A1 - Tompits, Hans A1 - Woltran, Stefan T1 - Paraconsistent reasoning via quantified boolean formulas Y1 - 2002 SN - 3-540-44190-5 ER - TY - JOUR A1 - Gebser, Martin A1 - Kaufmann, Benjamin A1 - Neumann, André A1 - Schaub, Torsten T1 - Clasp : a conflict-driven answer set solver Y1 - 2007 SN - 978-3-540- 72199-4 ER - TY - JOUR A1 - Brain, Martin A1 - Faber, Wolfgang A1 - Maratea, Marco A1 - Polleres, Axel A1 - Schaub, Torsten A1 - Schindlauer, Roman T1 - What should an ASP solver output? : a multiple position paper Y1 - 2007 ER - TY - JOUR A1 - Thielscher, Michael A1 - Schaub, Torsten T1 - Default reasoning by deductive planning Y1 - 1995 ER - TY - JOUR A1 - Banbara, Mutsunori A1 - Soh, Takehide A1 - Tamura, Naoyuki A1 - Inoue, Katsumi A1 - Schaub, Torsten T1 - Answer set programming as a modeling language for course timetabling JF - Theory and practice of logic programming N2 - 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. KW - answer set programming KW - educational timetabling KW - course timetabling Y1 - 2013 U6 - https://doi.org/10.1017/S1471068413000495 SN - 1471-0684 VL - 13 IS - 2 SP - 783 EP - 798 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Gebser, Martin A1 - Sabuncu, Orkunt A1 - Schaub, Torsten 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 - GEN A1 - Lifschitz, Vladimir A1 - Schaub, Torsten A1 - Woltran, Stefan T1 - Interview with Vladimir Lifschitz T2 - Künstliche Intelligenz N2 - This interview with Vladimir Lifschitz was conducted by Torsten Schaub at the University of Texas at Austin in August 2017. The question set was compiled by Torsten Schaub and Stefan Woltran. Y1 - 2018 U6 - https://doi.org/10.1007/s13218-018-0552-x SN - 0933-1875 SN - 1610-1987 VL - 32 IS - 2-3 SP - 213 EP - 218 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten A1 - Tompits, Hans T1 - A Preference-Based Framework for Updating logic Programs : preliminary reports Y1 - 2006 UR - http://www.easychair.org/FLoC-06/PREFS-preproceedings.pdf ER - TY - JOUR A1 - Linke, Thomas A1 - Schaub, Torsten T1 - An approach to query-answering in Reiter's default logic and the underlying existence of extensions problem. Y1 - 1998 SN - 3-540-65141-1 ER - TY - JOUR A1 - Gleiß, Alexander A1 - Degen, Konrad A1 - Knoth, Alexander A1 - Pousttchi, Key A1 - Lucke, Ulrike T1 - Governance principles and regulatory needs for a national digital education platform JF - Public policy and administration N2 - The educational sector currently faces a massive digital transformation with various digital offerings entering the market. To provide some orientation in this transforming space, a national digital education platform (NDEP) is under development in Germany as part of a nationwide flagship project. On the one hand, in efficiently connecting the relevant stakeholders to each other and to value-adding education-related offerings, various benefits emerge. On the other hand, monopolising the educational sector and influencing the respective market through a state-controlled platform bears potential regulatory risks from misuse of power by the platform to malpractice by the users. Against this background, we aim to identify and systematise these potential drawbacks prior to the platform’s actual development and implementation. We pursue a qualitative, interpretivist approach for policy analysis, based on ten elite interviews and two workshops. Our results are threefold: (1) We capture the consolidated NDEP architecture; (2) We categorise the range of relevant functions and value propositions of the NDEP; (3) We derive 23 regulatory areas of conflict across the three building blocks that result from the potential ecosystem and function scope configurations of the NDEP. As a contribution to research, we shed new interdisciplinary light on the governance and infrastructure of public-private platforms that enable innovation and collaboration while integrating respective market segments. As a contribution to practice, we provide clear guidance for policy-makers in strategizing the development and governance of and through national digital platforms in education. KW - education KW - information and communication technologies KW - governance KW - platform KW - policy making KW - regulation Y1 - 2023 U6 - https://doi.org/10.1177/09520767231202327 SN - 0952-0767 SN - 1749-4192 SP - 1 EP - 31 PB - Sage CY - London ER - TY - JOUR A1 - Roessner, Ute A1 - Luedemann, A. A1 - Brust, D. A1 - Fiehn, Oliver A1 - Linke, Thomas A1 - Willmitzer, Lothar A1 - Fernie, Alisdair T1 - Metabolic profiling allows comprehensive phenotyping of genetically or environmentally modified plant systems Y1 - 2001 SN - 1040-4651 ER - TY - JOUR A1 - Banbara, Mutsunori A1 - Inoue, Katsumi A1 - Kaufmann, Benjamin A1 - Okimoto, Tenda A1 - Schaub, Torsten A1 - Soh, Takehide A1 - Tamura, Naoyuki A1 - Wanko, Philipp T1 - teaspoon BT - solving the curriculum-based course timetabling problems with answer set programming JF - Annals of operation research N2 - Answer Set Programming (ASP) is an approach to declarative problem solving, combining a rich yet simple modeling language with high performance solving capacities. We here develop an ASP-based approach to curriculum-based course timetabling (CB-CTT), one of the most widely studied course timetabling problems. The resulting teaspoon system reads a CB-CTT instance of a standard input format and converts it into a set of ASP facts. In turn, these facts are combined with a first-order encoding for CB-CTT solving, which can subsequently be solved by any off-the-shelf ASP systems. We establish the competitiveness of our approach by empirically contrasting it to the best known bounds obtained so far via dedicated implementations. Furthermore, we extend the teaspoon system to multi-objective course timetabling and consider minimal perturbation problems. KW - Educational timetabling KW - Course timetabling KW - Answer set programming KW - Multi-objective optimization KW - Minimal perturbation problems Y1 - 2018 U6 - https://doi.org/10.1007/s10479-018-2757-7 SN - 0254-5330 SN - 1572-9338 VL - 275 IS - 1 SP - 3 EP - 37 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Frioux, Clémence A1 - Schaub, Torsten A1 - Schellhorn, Sebastian A1 - Siegel, Anne A1 - Wanko, Philipp T1 - Hybrid metabolic network completion JF - Theory and practice of logic programming N2 - Metabolic networks play a crucial role in biology since they capture all chemical reactions in an organism. While there are networks of high quality for many model organisms, networks for less studied organisms are often of poor quality and suffer from incompleteness. To this end, we introduced in previous work an answer set programming (ASP)-based approach to metabolic network completion. Although this qualitative approach allows for restoring moderately degraded networks, it fails to restore highly degraded ones. This is because it ignores quantitative constraints capturing reaction rates. To address this problem, we propose a hybrid approach to metabolic network completion that integrates our qualitative ASP approach with quantitative means for capturing reaction rates. We begin by formally reconciling existing stoichiometric and topological approaches to network completion in a unified formalism. With it, we develop a hybrid ASP encoding and rely upon the theory reasoning capacities of the ASP system dingo for solving the resulting logic program with linear constraints over reals. We empirically evaluate our approach by means of the metabolic network of Escherichia coli. Our analysis shows that our novel approach yields greatly superior results than obtainable from purely qualitative or quantitative approaches. KW - answer set programming KW - metabolic network KW - gap-filling KW - linear programming KW - hybrid solving KW - bioinformatics Y1 - 2018 U6 - https://doi.org/10.1017/S1471068418000455 SN - 1471-0684 SN - 1475-3081 VL - 19 IS - 1 SP - 83 EP - 108 PB - Cambridge University Press CY - New York ER - TY - GEN A1 - Neubauer, Kai A1 - Haubelt, Christian A1 - Wanko, Philipp A1 - Schaub, Torsten T1 - Utilizing quad-trees for efficient design space exploration with partial assignment evaluation T2 - 2018 23rd Asia and South Pacific Design Automation Conference (ASP-DAC) N2 - Recently, it has been shown that constraint-based symbolic solving techniques offer an efficient way for deciding binding and routing options in order to obtain a feasible system level implementation. In combination with various background theories, a feasibility analysis of the resulting system may already be performed on partial solutions. That is, infeasible subsets of mapping and routing options can be pruned early in the decision process, which fastens the solving accordingly. However, allowing a proper design space exploration including multi-objective optimization also requires an efficient structure for storing and managing non-dominated solutions. In this work, we propose and study the usage of the Quad-Tree data structure in the context of partial assignment evaluation during system synthesis. Out experiments show that unnecessary dominance checks can be avoided, which indicates a preference of Quad-Trees over a commonly used list-based implementation for large combinatorial optimization problems. Y1 - 2018 SN - 978-1-5090-0602-1 U6 - https://doi.org/10.1109/ASPDAC.2018.8297362 SN - 2153-6961 SP - 434 EP - 439 PB - IEEE CY - New York ER - TY - JOUR A1 - Gebser, Martin A1 - Kaminski, Roland A1 - Kaufmann, Benjamin A1 - Lühne, Patrick A1 - Obermeier, Philipp A1 - Ostrowski, Max A1 - Romero Davila, Javier A1 - Schaub, Torsten A1 - Schellhorn, Sebastian A1 - Wanko, Philipp T1 - The Potsdam Answer Set Solving Collection 5.0 JF - Künstliche Intelligenz N2 - The Potsdam answer set solving collection, or Potassco for short, bundles various tools implementing and/or applying answer set programming. The article at hand succeeds an earlier description of the Potassco project published in Gebser et al. (AI Commun 24(2):107-124, 2011). Hence, we concentrate in what follows on the major features of the most recent, fifth generation of the ASP system clingo and highlight some recent resulting application systems. Y1 - 2018 U6 - https://doi.org/10.1007/s13218-018-0528-x SN - 0933-1875 SN - 1610-1987 VL - 32 IS - 2-3 SP - 181 EP - 182 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Haubelt, Christian A1 - Neubauer, Kai A1 - Schaub, Torsten A1 - Wanko, Philipp T1 - Design space exploration with answer set programming JF - Künstliche Intelligenz N2 - The aim of our project design space exploration with answer set programming is to develop a general framework based on Answer Set Programming (ASP) that finds valid solutions to the system design problem and simultaneously performs Design Space Exploration (DSE) to find the most favorable alternatives. We leverage recent developments in ASP solving that allow for tight integration of background theories to create a holistic framework for effective DSE. Y1 - 2018 U6 - https://doi.org/10.1007/s13218-018-0530-3 SN - 0933-1875 SN - 1610-1987 VL - 32 IS - 2-3 SP - 205 EP - 206 PB - Springer CY - Heidelberg ER -