@article{DelgrandeSchaub2004, author = {Delgrande, James Patrick and Schaub, Torsten}, title = {Two approaches to merging knowledge bases}, isbn = {3-540-23242-7}, year = {2004}, language = {en} } @article{DelgrandeSchaubTompitsetal.2002, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans and Wang, Kewen}, title = {Towards a classification of preference handling approaches in nonmonotonic reasoning}, isbn = {1-577-35166-5}, year = {2002}, language = {en} } @article{DelgrandeSchaubTompitsetal.2001, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans and Woltran, Stefan}, title = {On computing solutions to belief change scenarios}, isbn = {3-540- 42464-4}, year = {2001}, language = {en} } @article{DelgrandeSchaub2001, author = {Delgrande, James Patrick and Schaub, Torsten}, title = {How to reason credulously and skeptically within a single extension.}, isbn = {3-540- 42464-4}, year = {2001}, language = {en} } @article{SchaubWang2001, author = {Schaub, Torsten and Wang, Kewen}, title = {A comparative study of logic programs with preference}, isbn = {1-558-60777-3}, issn = {1045-0823}, year = {2001}, language = {en} } @article{DelgrandeSchaubTompits2001, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans}, title = {A generic compiler for ordered logic programs}, isbn = {3-540-42593-4}, year = {2001}, language = {en} } @article{PearceSarsakovSchaubetal.2002, author = {Pearce, David and Sarsakov, Vladimir and Schaub, Torsten and Tompits, Hans and Woltran, Stefan}, title = {A polynomial translation of logic programs with nested expressions into disjunctive logic programs : preliminary report}, year = {2002}, language = {en} } @article{BesnardMercerSchaub2002, author = {Besnard, Philippe and Mercer, Robert E. and Schaub, Torsten}, title = {Optimality Theory via Default Logic}, year = {2002}, language = {en} } @article{LinkeSchaub2000, author = {Linke, Thomas and Schaub, Torsten}, title = {Alternative foundations for Reiter's default logic.}, issn = {0004-3702}, year = {2000}, language = {en} } @book{OPUS4-18498, title = {Proceedings of the Fifth Dutch German Workshop on Nonmonotonic Reasoning Techniques and their Applications, DGNMR'2001, Potsdam, 4. - 6. April 2001}, editor = {Brewka, Gerhard and Witteveen, Cees and Schaub, Torsten}, address = {Potsdam}, year = {2001}, language = {en} } @article{BenhammadiNicolasSchaub1998, author = {Benhammadi, Farid and Nicolas, Pascal and Schaub, Torsten}, title = {Extension calculus and query answering in prioritized default logic}, isbn = {3-540- 64993-X}, year = {1998}, language = {en} } @article{BenhammadiNicolasSchaub1998, author = {Benhammadi, Farid and Nicolas, Pascal and Schaub, Torsten}, title = {Extension calculus and query answering in prioritized default logic}, isbn = {3-540-64993-X}, year = {1998}, language = {en} } @article{DelgrandeSchaub1998, author = {Delgrande, James Patrick and Schaub, Torsten}, title = {Reasoning with sets of preferences in default logic}, isbn = {3-540- 65271-x}, year = {1998}, language = {en} } @article{BibelBrueningOttenetal.1998, author = {Bibel, Wolfgang and Br{\"u}ning, Stefan and Otten, Jens and Rath, Thomas and Schaub, Torsten}, title = {Compressions and extensions}, year = {1998}, language = {en} } @article{BesnardSchaub1998, author = {Besnard, Philippe and Schaub, Torsten}, title = {Characterization of non-monotone non-constructive systems}, issn = {1012-2443}, year = {1998}, language = {en} } @article{BesnardSchaub1998, author = {Besnard, Philippe and Schaub, Torsten}, title = {Signed systems for paraconsistent reasoning}, issn = {0168-7433}, year = {1998}, language = {en} } @article{SchaubBruening1998, author = {Schaub, Torsten and Br{\"u}ning, Stefan}, title = {Prolog technology for default reasoning : proof theory and compilation techniques}, year = {1998}, language = {en} } @article{Schaub1998, author = {Schaub, Torsten}, title = {The family of default logics}, year = {1998}, language = {en} } @article{DelgrandeSchaubTompitsetal.2013, author = {Delgrande, James and Schaub, Torsten and Tompits, Hans and Woltran, Stefan}, title = {A model-theoretic approach to belief change in answer set programming}, series = {ACM transactions on computational logic}, volume = {14}, journal = {ACM transactions on computational logic}, number = {2}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {1529-3785}, doi = {10.1145/2480759.2480766}, pages = {46}, year = {2013}, abstract = {We address the problem of belief change in (nonmonotonic) logic programming under answer set semantics. Our formal techniques are analogous to those of distance-based belief revision in propositional logic. In particular, we build upon the model theory of logic programs furnished by SE interpretations, where an SE interpretation is a model of a logic program in the same way that a classical interpretation is a model of a propositional formula. Hence we extend techniques from the area of belief revision based on distance between models to belief change in logic programs. We first consider belief revision: for logic programs P and Q, the goal is to determine a program R that corresponds to the revision of P by Q, denoted P * Q. We investigate several operators, including (logic program) expansion and two revision operators based on the distance between the SE models of logic programs. It proves to be the case that expansion is an interesting operator in its own right, unlike in classical belief revision where it is relatively uninteresting. Expansion and revision are shown to satisfy a suite of interesting properties; in particular, our revision operators satisfy all or nearly all of the AGM postulates for revision. We next consider approaches for merging a set of logic programs, P-1,...,P-n. Again, our formal techniques are based on notions of relative distance between the SE models of the logic programs. Two approaches are examined. The first informally selects for each program P-i those models of P-i that vary the least from models of the other programs. The second approach informally selects those models of a program P-0 that are closest to the models of programs P-1,...,P-n. In this case, P-0 can be thought of as a set of database integrity constraints. We examine these operators with regards to how they satisfy relevant postulate sets. Last, we present encodings for computing the revision as well as the merging of logic programs within the same logic programming framework. This gives rise to a direct implementation of our approach in terms of off-the-shelf answer set solvers. These encodings also reflect the fact that our change operators do not increase the complexity of the base formalism.}, language = {en} } @article{DelgrandeSchaubTompits2007, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans}, title = {A general framework for expressing preferences in causal reasoning and planning}, issn = {0955-792X}, doi = {10.1093/logcom/exm046}, year = {2007}, abstract = {We consider the problem of representing arbitrary preferences in causal reasoning and planning systems. In planning, a preference may be seen as a goal or constraint that is desirable, but not necessary, to satisfy. To begin, we define a very general query language for histories, or interleaved sequences of world states and actions. Based on this, we specify a second language in which preferences are defined. A single preference defines a binary relation on histories, indicating that one history is preferred to the other. From this, one can define global preference orderings on the set of histories, the maximal elements of which are the preferred histories. The approach is very general and flexible; thus it constitutes a base language in terms of which higher-level preferences may be defined. To this end, we investigate two fundamental types of preferences that we call choice and temporal preferences. We consider concrete strategies for these types of preferences and encode them in terms of our framework. We suggest how to express aggregates in the approach, allowing, e.g. the expression of a preference for histories with lowest total action costs. Last, our approach can be used to express other approaches and so serves as a common framework in which such approaches can be expressed and compared. We illustrate this by indicating how an approach due to Son and Pontelli can be encoded in our approach, as well as the language PDDL3.}, language = {en} } @article{GebserSchaubThieleetal.2011, author = {Gebser, Martin and Schaub, Torsten and Thiele, Sven and Veber, Philippe}, title = {Detecting inconsistencies in large biological networks with answer set programming}, series = {Theory and practice of logic programming}, volume = {11}, journal = {Theory and practice of logic programming}, number = {5-6}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068410000554}, pages = {323 -- 360}, year = {2011}, abstract = {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.}, language = {en} } @article{GebserKaminskiSchaub2011, author = {Gebser, Martin and Kaminski, Roland and Schaub, Torsten}, title = {Complex optimization in answer set programming}, series = {Theory and practice of logic programming}, volume = {11}, journal = {Theory and practice of logic programming}, number = {3}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068411000329}, pages = {821 -- 839}, year = {2011}, abstract = {Preference handling and optimization are indispensable means for addressing nontrivial applications in Answer Set Programming (ASP). However, their implementation becomes difficult whenever they bring about a significant increase in computational complexity. As a consequence, existing ASP systems do not offer complex optimization capacities, supporting, for instance, inclusion-based minimization or Pareto efficiency. Rather, such complex criteria are typically addressed by resorting to dedicated modeling techniques, like saturation. Unlike the ease of common ASP modeling, however, these techniques are rather involved and hardly usable by ASP laymen. We address this problem by developing a general implementation technique by means of meta-prpogramming, thus reusing existing ASP systems to capture various forms of qualitative preferences among answer sets. In this way, complex preferences and optimization capacities become readily available for ASP applications.}, language = {en} } @article{GebserGharibMerceretal.2009, author = {Gebser, Martin and Gharib, Mona and Mercer, Robert E. and Schaub, Torsten}, title = {Monotonic answer set programming}, issn = {0955-792X}, doi = {10.1093/logcom/exn040}, year = {2009}, abstract = {Answer set programming (ASP) does not allow for incrementally constructing answer sets or locally validating constructions like proofs by only looking at a part of the given program. In this article, we elaborate upon an alternative approach to ASP that allows for incremental constructions. Our approach draws its basic intuitions from the area of default logics. We investigate the feasibility of the concept of semi-monotonicity known from default logics as a basis of incrementality. On the one hand, every logic program has at least one answer set in our alternative setting, which moreover can be constructed incrementally based on generating rules. On the other hand, the approach may produce answer sets lacking characteristic properties of standard answer sets, such as being a model of the given program. We show how integrity constraints can be used to re-establish such properties, even up to correspondence with standard answer sets. Furthermore, we develop an SLD-like proof procedure for our incremental approach to ASP, which allows for query-oriented computations. Also, we provide a characterization of our definition of answer sets via a modification of Clarks completion. Based on this notion of program completion, we present an algorithm for computing the answer sets of a logic program in our approach.}, language = {en} } @article{GebserKaufmannSchaub2012, author = {Gebser, Martin and Kaufmann, Benjamin and Schaub, Torsten}, title = {Multi-threaded ASP solving with clasp}, series = {Theory and practice of logic programming}, volume = {12}, journal = {Theory and practice of logic programming}, number = {8}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {1471-0684}, doi = {10.1017/S1471068412000166}, pages = {525 -- 545}, year = {2012}, abstract = {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.}, language = {en} } @article{HermenegildoSchaub2010, author = {Hermenegildo, Manuel and Schaub, Torsten}, title = {Introduction to the technical communications of the 26th International Conference on Logic Programming : special issue}, issn = {1471-0684}, doi = {10.1017/S1471068410000153}, year = {2010}, language = {en} } @article{DelgrandeLiuSchaubetal.2007, author = {Delgrande, James Patrick and Liu, Daphne H. and Schaub, Torsten and Thiele, Sven}, title = {COBA 2.0 : a consistency-based belief change system}, year = {2007}, language = {en} } @article{GharibSchaubMercer2007, author = {Gharib, Mona and Schaub, Torsten and Mercer, Robert E.}, title = {Incremental answer set programming : a preliminary report}, year = {2007}, language = {en} } @article{DelgrandeSchaubTompits2006, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans}, title = {An Extended Query language for action languages (and its application to aggregates and preferences)}, year = {2006}, language = {en} } @article{KonczakLinkeSchaub2003, author = {Konczak, Kathrin and Linke, Thomas and Schaub, Torsten}, title = {Graphs and colorings for answer set programming : abridged report}, issn = {1613-0073}, year = {2003}, language = {en} } @article{AngerGebserSchaub2006, author = {Anger, Christian and Gebser, Martin and Schaub, Torsten}, title = {Approaching the core of unfounded sets}, year = {2006}, language = {en} } @article{MileoSchaub2006, author = {Mileo, Alessandra and Schaub, Torsten}, title = {Extending ordered disjunctions for policy enforcement : preliminary report}, year = {2006}, language = {en} } @article{DelgrandeSchaubTompits2007, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans}, title = {A preference-based framework for updating logic programs}, isbn = {978-3-540- 72199-4}, year = {2007}, language = {en} } @article{GressmannJanhunenMerceretal.2006, author = {Gressmann, Jean and Janhunen, Tomi and Mercer, Robert E. and Schaub, Torsten and Thiele, Sven and Tichy, Richard}, title = {On probing and multi-threading in platypus}, year = {2006}, language = {en} } @article{GrellSchaubSelbig2006, author = {Grell, Susanne and Schaub, Torsten and Selbig, Joachim}, title = {Modelling biological networks by action languages via set programming}, issn = {0302-9743}, doi = {10.1007/11799573}, year = {2006}, language = {en} } @article{GerbserSchaub2006, author = {Gerbser, Martin and Schaub, Torsten}, title = {Tableau calculi for answer set programming}, issn = {0302-9743}, doi = {10.1007/11799573}, year = {2006}, language = {en} } @article{GerbserSchaub2006, author = {Gerbser, Martin and Schaub, Torsten}, title = {Characterizing (ASP) inferences by unit propagation}, year = {2006}, language = {en} } @phdthesis{Kaufmann2015, author = {Kaufmann, Benjamin}, title = {High performance answer set solving}, pages = {182}, year = {2015}, language = {en} } @article{DelgrandeSchaubTompitsetal.2004, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans and Woltran, Stefan}, title = {On Computing belief change operations using quantifield boolean formulas}, issn = {0955-792X}, year = {2004}, abstract = {In this paper, we show how an approach to belief revision and belief contraction can be axiomatized by means of quantified Boolean formulas. Specifically, we consider the approach of belief change scenarios, a general framework that has been introduced for expressing different forms of belief change. The essential idea is that for a belief change scenario (K, R, C), the set of formulas K, representing the knowledge base, is modified so that the sets of formulas R and C are respectively true in, and consistent with the result. By restricting the form of a belief change scenario, one obtains specific belief change operators including belief revision, contraction, update, and merging. For both the general approach and for specific operators, we give a quantified Boolean formula such that satisfying truth assignments to the free variables correspond to belief change extensions in the original approach. Hence, we reduce the problem of determining the results of a belief change operation to that of satisfiability. This approach has several benefits. First, it furnishes an axiomatic specification of belief change with respect to belief change scenarios. This then leads to further insight into the belief change framework. Second, this axiomatization allows us to identify strict complexity bounds for the considered reasoning tasks. Third, we have implemented these different forms of belief change by means of existing solvers for quantified Boolean formulas. As well, it appears that this approach may be straightforwardly applied to other specific approaches to belief change}, language = {en} } @article{FloeterNicolasSchaubetal.2004, author = {Fl{\"o}ter, Andr{\´e} and Nicolas, Jacques and Schaub, Torsten and Selbig, Joachim}, title = {Threshold extraction in metabolite concentration data}, year = {2004}, abstract = {Motivation: Continued development of analytical techniques based on gas chromatography and mass spectrometry now facilitates the generation of larger sets of metabolite concentration data. An important step towards the understanding of metabolite dynamics is the recognition of stable states where metabolite concentrations exhibit a simple behaviour. Such states can be characterized through the identification of significant thresholds in the concentrations. But general techniques for finding discretization thresholds in continuous data prove to be practically insufficient for detecting states due to the weak conditional dependences in concentration data. Results: We introduce a method of recognizing states in the framework of decision tree induction. It is based upon a global analysis of decision forests where stability and quality are evaluated. It leads to the detection of thresholds that are both comprehensible and robust. Applied to metabolite concentration data, this method has led to the discovery of hidden states in the corresponding variables. Some of these reflect known properties of the biological experiments, and others point to putative new states}, language = {en} } @article{DelgrandeGharibMerceretal.2003, author = {Delgrande, James Patrick and Gharib, Mona and Mercer, Robert E. and Risch, V. and Schaub, Torsten}, title = {Lukaszewicz-style answer set programming : a preliminary report}, issn = {1613-0073}, year = {2003}, language = {en} } @article{DelgrandeSchaub2003, author = {Delgrande, James Patrick and Schaub, Torsten}, title = {On the relation between Reiter{\"i}s default logic and its (major) variants}, isbn = {3-540- 409494-5}, year = {2003}, language = {en} } @article{KonczakSchaubLinke2003, author = {Konczak, Kathrin and Schaub, Torsten and Linke, Thomas}, title = {Graphs and colorings for answer set programming with prefernces : preliminary report}, issn = {1613-0073}, year = {2003}, language = {en} } @article{BesnardMercerSchaub2003, author = {Besnard, Philippe and Mercer, Robert E. and Schaub, Torsten}, title = {Optimality theory throught default logic}, isbn = {3-540-20059-2}, year = {2003}, language = {en} } @article{DelgrandeSchaubTompits2003, author = {Delgrande, James Patrick and Schaub, Torsten and Tompits, Hans}, title = {A framework for compiling preferences in logic programs}, year = {2003}, language = {en} } @article{DelgrandeSchaub2003, author = {Delgrande, James Patrick and Schaub, Torsten}, title = {Reasoning credulously and skeptically within a single extension}, year = {2003}, language = {en} } @article{SchaubWang2003, author = {Schaub, Torsten and Wang, Kewen}, title = {A semantic framework for prefernce handling in answer set programming}, year = {2003}, language = {en} } @article{BenhammadiNicolasSchaub1999, author = {Benhammadi, Farid and Nicolas, Pascal and Schaub, Torsten}, title = {Query-answering in prioritized default logic}, isbn = {3-540-66131-X}, year = {1999}, language = {en} } @article{LinkeSchaub1999, author = {Linke, Thomas and Schaub, Torsten}, title = {On bottom-up pre-processing techniques for automated default reasoning}, isbn = {3-540-66131-x}, year = {1999}, language = {en} } @article{BenhammadiNicolasSchaub1999, author = {Benhammadi, Farid and Nicolas, Pascal and Schaub, Torsten}, title = {Query-answering in prioritized default logic}, isbn = {3-540-66131-X}, year = {1999}, language = {en} } @article{BrueningSchaub1999, author = {Br{\"u}ning, Stefan and Schaub, Torsten}, title = {Avoiding non-ground variables}, isbn = {3-540-66131-x}, year = {1999}, language = {en} }