@article{DelgrandeSchaubTompitsetal.2013, author = {Delgrande, James and Schaub, Torsten H. and Tompits, Hans and Woltran, Stefan}, title = {A model-theoretic approach to belief change in answer set programming}, series = {ACM transactions on computational logic}, volume = {14}, journal = {ACM transactions on computational logic}, number = {2}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {1529-3785}, doi = {10.1145/2480759.2480766}, pages = {46}, year = {2013}, abstract = {We address the problem of belief change in (nonmonotonic) logic programming under answer set semantics. Our formal techniques are analogous to those of distance-based belief revision in propositional logic. In particular, we build upon the model theory of logic programs furnished by SE interpretations, where an SE interpretation is a model of a logic program in the same way that a classical interpretation is a model of a propositional formula. Hence we extend techniques from the area of belief revision based on distance between models to belief change in logic programs. We first consider belief revision: for logic programs P and Q, the goal is to determine a program R that corresponds to the revision of P by Q, denoted P * Q. We investigate several operators, including (logic program) expansion and two revision operators based on the distance between the SE models of logic programs. It proves to be the case that expansion is an interesting operator in its own right, unlike in classical belief revision where it is relatively uninteresting. Expansion and revision are shown to satisfy a suite of interesting properties; in particular, our revision operators satisfy all or nearly all of the AGM postulates for revision. We next consider approaches for merging a set of logic programs, P-1,...,P-n. Again, our formal techniques are based on notions of relative distance between the SE models of the logic programs. Two approaches are examined. The first informally selects for each program P-i those models of P-i that vary the least from models of the other programs. The second approach informally selects those models of a program P-0 that are closest to the models of programs P-1,...,P-n. In this case, P-0 can be thought of as a set of database integrity constraints. We examine these operators with regards to how they satisfy relevant postulate sets. Last, we present encodings for computing the revision as well as the merging of logic programs within the same logic programming framework. This gives rise to a direct implementation of our approach in terms of off-the-shelf answer set solvers. These encodings also reflect the fact that our change operators do not increase the complexity of the base formalism.}, language = {en} } @article{BrainGebserPuehreretal.2007, author = {Brain, Martin and Gebser, Martin and P{\"u}hrer, J{\"o}rg and Schaub, Torsten H. and Tompits, Hans and Woltran, Stefan}, title = {Debugging ASP programs by means of ASP}, isbn = {978-3-540- 72199-4}, year = {2007}, language = {en} } @article{GebserSchaubTompitsetal.2007, author = {Gebser, Martin and Schaub, Torsten H. and Tompits, Hans and Woltran, Stefan}, title = {Alternative characterizations for program equivalence under aswer-set semantics : a preliminary report}, year = {2007}, language = {en} } @misc{SchaepersNiemuellerLakemeyeretal.2018, author = {Sch{\"a}pers, Bj{\"o}rn and Niemueller, Tim and Lakemeyer, Gerhard and Gebser, Martin and Schaub, Torsten H.}, title = {ASP-Based Time-Bounded Planning for Logistics Robots}, series = {Twenty-Eighth International Conference on Automated Planning and Scheduling (ICAPS 2018)}, journal = {Twenty-Eighth International Conference on Automated Planning and Scheduling (ICAPS 2018)}, publisher = {ASSOC Association for the Advancement of Artificial Intelligence}, address = {Palo Alto}, issn = {2334-0835}, pages = {509 -- 517}, year = {2018}, abstract = {Manufacturing industries are undergoing a major paradigm shift towards more autonomy. Automated planning and scheduling then becomes a necessity. The Planning and Execution Competition for Logistics Robots in Simulation held at ICAPS is based on this scenario and provides an interesting testbed. However, the posed problem is challenging as also demonstrated by the somewhat weak results in 2017. The domain requires temporal reasoning and dealing with uncertainty. We propose a novel planning system based on Answer Set Programming and the Clingo solver to tackle these problems and incentivize robot cooperation. Our results show a significant performance improvement, both, in terms of lowering computational requirements and better game metrics.}, language = {en} } @article{GrellSchaubSelbig2006, author = {Grell, Susanne and Schaub, Torsten H. 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{DelgrandeSchaubTompits2006, author = {Delgrande, James Patrick and Schaub, Torsten H. and Tompits, Hans}, title = {A Preference-Based Framework for Updating logic Programs : preliminary reports}, year = {2006}, language = {en} } @article{GressmannJanhunenMerceretal.2006, author = {Gressmann, Jean and Janhunen, Tomi and Mercer, Robert E. and Schaub, Torsten H. and Thiele, Sven and Tichy, Richard}, title = {On probing and multi-threading in platypus}, year = {2006}, language = {en} } @article{AngerGebserSchaub2006, author = {Anger, Christian and Gebser, Martin and Schaub, Torsten H.}, title = {Approaching the core of unfounded sets}, year = {2006}, language = {en} } @article{GerbserSchaub2006, author = {Gerbser, Martin and Schaub, Torsten H.}, title = {Tableau calculi for answer set programming}, issn = {0302-9743}, doi = {10.1007/11799573}, year = {2006}, language = {en} } @article{AngerGebserJanhunenetal.2006, author = {Anger, Christian and Gebser, Martin and Janhunen, Tomi and Schaub, Torsten H.}, title = {What's a head without a body?}, year = {2006}, language = {en} } @article{GerbserSchaub2006, author = {Gerbser, Martin and Schaub, Torsten H.}, title = {Characterizing (ASP) inferences by unit propagation}, year = {2006}, language = {en} } @article{DelgrandeSchaubTompits2007, author = {Delgrande, James Patrick and Schaub, Torsten H. and Tompits, Hans}, title = {A preference-based framework for updating logic programs}, isbn = {978-3-540- 72199-4}, year = {2007}, language = {en} } @article{MileoSchaub2007, author = {Mileo, Alessandra and Schaub, Torsten H.}, title = {Qualitative constraint enforcement in advanced policy specification}, year = {2007}, language = {en} } @article{DelgrandeLangSchaub2007, author = {Delgrande, James Patrick and Lang, J{\´e}r{\^o}me and Schaub, Torsten H.}, title = {Belief change based on global minimisation}, year = {2007}, language = {en} } @article{KonczakLinkeSchaub2006, author = {Konczak, Kathrin and Linke, Thomas and Schaub, Torsten H.}, title = {Graphs and colorings for answer set programming}, issn = {1471-0684}, doi = {10.1017/S1471068405002528}, year = {2006}, abstract = {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}, language = {en} } @article{GebserSchaubThiele2007, author = {Gebser, Martin and Schaub, Torsten H. and Thiele, Sven}, title = {GrinGo : a new grounder for answer set programming}, isbn = {978-3-540- 72199-4}, year = {2007}, language = {en} } @article{KonczakLinkeSchaub2004, author = {Konczak, Kathrin and Linke, Thomas and Schaub, Torsten H.}, title = {Graphs and cologings for answer set programming : adridged report}, isbn = {3-540- 20721-x}, year = {2004}, language = {en} } @article{BoeselLinkeSchaub2004, author = {Boesel, Andreas and Linke, Thomas and Schaub, Torsten H.}, title = {Profiling answer set programming : the visualization component of the noMoRe System}, isbn = {3-540-23242-7}, year = {2004}, language = {en} } @article{GressmannJanhunenMerceretal.2006, author = {Gressmann, Jean and Janhunen, Tomi and Mercer, Robert E. and Schaub, Torsten H. and Thiele, Sven and Tichy, Richard}, title = {On probing and multi-threading in platypus}, year = {2006}, language = {en} } @article{MileoSchaub2006, author = {Mileo, Alessandra and Schaub, Torsten H.}, title = {Extending ordered disjunctions for policy enforcement : preliminary report}, year = {2006}, language = {en} } @article{DelgrandeLiuSchaubetal.2006, author = {Delgrande, James Patrick and Liu, Daphne H. and Schaub, Torsten H. and Thiele, Sven}, title = {COBA 2.0 : a consistency-based belief change system}, year = {2006}, language = {en} } @article{DelgrandeSchaubTompits2006, author = {Delgrande, James Patrick and Schaub, Torsten H. and Tompits, Hans}, title = {An Extended Query language for action languages (and its application to aggregates and preferences)}, year = {2006}, language = {en} } @article{AngerGebserLinkeetal.2005, author = {Anger, Christian and Gebser, Martin and Linke, Thomas and Neumann, Andre and Schaub, Torsten H.}, title = {The nomore++ approach to answer set solving}, year = {2005}, language = {en} } @article{GressmannJanhunenMerceretal.2005, author = {Gressmann, Jean and Janhunen, Tomi and Mercer, Robert E. and Schaub, Torsten H. and Thiele, Sven and Tichy, Richard}, title = {Platypus : a platform for distributed answer set solving}, year = {2005}, language = {en} } @article{AngerGebserLinkeetal.2005, author = {Anger, Christian and Gebser, Martin and Linke, Thomas and Neumann, Andre and Schaub, Torsten H.}, title = {The nomore++ approach to answer set solving}, year = {2005}, language = {en} } @article{GrellKonczakSchaub2005, author = {Grell, Susanne and Konczak, Kathrin and Schaub, Torsten H.}, title = {nomore) : a system for computing preferred Answer Sets}, issn = {0302-9743}, year = {2005}, language = {en} } @article{AngerKonczakLinkeetal.2005, author = {Anger, Christian and Konczak, Kathrin and Linke, Thomas and Schaub, Torsten H.}, title = {A Glimpse of Answer Set Programming}, issn = {0170-4516}, year = {2005}, language = {en} } @article{DelgrandeSchaub2005, author = {Delgrande, James Patrick and Schaub, Torsten H.}, title = {Expressing default logic variants in default logic}, issn = {0955-792X}, year = {2005}, abstract = {Reiter's default logic is one of the best known and most studied of the approaches to nonmonotonic reasoning. Several variants of default logic have subsequently been proposed to give systems with properties differing from the original. In this paper, we examine the relationship between default logic and its major variants. We accomplish this by translating a default theory under a variant interpretation into a second default theory, under the original Reiter semantics, wherein the variant interpretation is respected. That is, in each case we show that, given an extension of a translated theory, one may extract an extension of the original variant default logic theory. We show how constrained, rational, justified, and cumulative default logic can be expressed in Reiter's default logic. As well, we show how Reiter's default logic can be expressed in rational default logic. From this, we suggest that any such variant can be similarly treated. Consequently, we provide a unification of default logics, showing how the original formulation of default logic may express its variants. Moreover, the translations clearly express the relationships between alternative approaches to default logic. The translations themselves are shown to generally have good properties. Thus, in at least a theoretical sense, we show that these variants are in a sense superfluous, in that for any of these variants of default logic, we can exactly mimic the behaviour of a variant in standard default logic. As well, the translations lend insight into means of classifying the expressive power of default logic variants; specifically we suggest that the property of semi-monotonicity represents a division with respect to expressibility, whereas regularity and cumulativity do not}, language = {en} } @article{GebserLiuNamasivayametal.2007, author = {Gebser, Martin and Liu, Lengning and Namasivayam, Gayathri and Neumann, Andr{\´e} and Schaub, Torsten H. and Truszczynski, Miroslaw}, title = {The first answer set programming system competition}, isbn = {978-3-540- 72199-4}, year = {2007}, language = {en} } @article{BorchertAngerSchaubetal.2004, author = {Borchert, P. and Anger, Christian and Schaub, Torsten H. and Truszczynski, M.}, title = {Towards systematic benchmarking in answer set programming : the dagstuhl initiative}, isbn = {3-540- 20721-x}, year = {2004}, language = {en} } @article{DelgrandeSchaub2004, author = {Delgrande, James Patrick and Schaub, Torsten H.}, title = {Two approaches to merging knowledge bases}, isbn = {3-540-23242-7}, year = {2004}, language = {en} } @article{DelgrandeSchaubTompits2004, author = {Delgrande, James Patrick and Schaub, Torsten H. and Tompits, Hans}, title = {Domain-specific preference for causal reasoning and planning}, isbn = {1-577-35201-7}, year = {2004}, language = {en} } @article{FloeterSelbigSchaub2004, author = {Fl{\"o}ter, Andr{\´e} and Selbig, Joachim and Schaub, Torsten H.}, title = {Finding metabolic pathways in decision forests}, isbn = {3-540-23221-4}, year = {2004}, language = {en} } @article{DelgrandeSchaub2004, author = {Delgrande, James Patrick and Schaub, Torsten H.}, title = {Consistency-based approaches to merging knowledge based : preliminary report}, isbn = {92-990021-0-X}, year = {2004}, language = {en} } @article{FloeterNicolasSchaubetal.2004, author = {Fl{\"o}ter, Andr{\´e} and Nicolas, Jacques and Schaub, Torsten H. 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{DelgrandeSchaubTompitsetal.2004, author = {Delgrande, James Patrick and Schaub, Torsten H. and Tompits, Hans and Wang, Kewen}, title = {A classification and survey of preference handling approchaches in nonmonotonic reasoning}, issn = {0824-7935}, year = {2004}, abstract = {In recent years, there has been a large amount of disparate work concerning the representation and reasoning with qualitative preferential information by means of approaches to nonmonotonic reasoning. Given the variety of underlying systems, assumptions, motivations, and intuitions, it is difficult to compare or relate one approach with another. Here, we present an overview and classification for approaches to dealing with preference. A set of criteria for classifying approaches is given, followed by a set of desiderata that an approach might be expected to satisfy. A comprehensive set of approaches is subsequently given and classified with respect to these sets of underlying principles}, language = {en} } @article{DelgrandeSchaub2004, author = {Delgrande, James Patrick and Schaub, Torsten H.}, title = {Reasoning with sets of preferences in default logic}, issn = {0824-7935}, year = {2004}, abstract = {We present a general approach for representing and reasoning with sets of defaults in default logic, focusing on reasoning about preferences among sets of defaults. First, we consider how to control the application of a set of defaults so that either all apply (if possible) or none do (if not). From this, an approach to dealing with preferences among sets of default rules is developed. We begin with an ordered default theory, consisting of a standard default theory, but with possible preferences on sets of rules. This theory is transformed into a second, standard default theory wherein the preferences are respected. The approach differs from other work, in that we obtain standard default theories and do not rely on prioritized versions of default logic. In practical terms this means we can immediately use existing default logic theorem provers for an implementation. Also, we directly generate just those extensions containing the most preferred applied rules; in contrast, most previous approaches generate all extensions, then select the most preferred. In a major application of the approach, we show how semimonotonic default theories can be encoded so that reasoning can be carried out at the object level. With this, we can reason about default extensions from within the framework of a standard default logic. Hence one can encode notions such as skeptical and credulous conclusions, and can reason about such conclusions within a single extension}, language = {en} } @article{DelgrandeSchaubTompits2003, author = {Delgrande, James Patrick and Schaub, Torsten H. 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 H.}, title = {Reasoning credulously and skeptically within a single extension}, year = {2003}, language = {en} } @article{KonczakLinkeSchaub2003, author = {Konczak, Kathrin and Linke, Thomas and Schaub, Torsten H.}, title = {Graphs and colorings for answer set programming : abridged report}, issn = {1613-0073}, year = {2003}, language = {en} } @article{DelgrandeSchaub2003, author = {Delgrande, James Patrick and Schaub, Torsten H.}, title = {On the relation between Reiter{\"i}s default logic and its (major) variants}, isbn = {3-540- 409494-5}, year = {2003}, language = {en} } @article{BesnardMercerSchaub2003, author = {Besnard, Philippe and Mercer, Robert E. and Schaub, Torsten H.}, title = {Optimality theory throught default logic}, isbn = {3-540-20059-2}, year = {2003}, language = {en} } @article{KonczakSchaubLinke2003, author = {Konczak, Kathrin and Schaub, Torsten H. and Linke, Thomas}, title = {Graphs and colorings for answer set programming with prefernces : preliminary report}, issn = {1613-0073}, year = {2003}, language = {en} } @article{DelgrandeGharibMerceretal.2003, author = {Delgrande, James Patrick and Gharib, Mona and Mercer, Robert E. and Risch, V. and Schaub, Torsten H.}, title = {Lukaszewicz-style answer set programming : a preliminary report}, issn = {1613-0073}, year = {2003}, language = {en} } @article{SchaubWang2003, author = {Schaub, Torsten H. and Wang, Kewen}, title = {A semantic framework for prefernce handling in answer set programming}, year = {2003}, language = {en} } @article{DelgrandeSchaub2003, author = {Delgrande, James Patrick and Schaub, Torsten H.}, title = {A concictency-based paradigm for belief change}, issn = {0004-3702}, year = {2003}, language = {en} } @article{Schaub2003, author = {Schaub, Torsten H.}, title = {Antwortmengenprogrammierung}, year = {2003}, language = {de} } @article{KonczakSchaubLinke2003, author = {Konczak, Kathrin and Schaub, Torsten H. and Linke, Thomas}, title = {Graphs and colorings for answer set programming with preferences}, issn = {0169-2968}, year = {2003}, abstract = {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}, language = {en} } @article{FloeterNicolasSchaubetal.2003, author = {Fl{\"o}ter, Andr{\´e} and Nicolas, Jacques and Schaub, Torsten H. and Selbig, Joachim}, title = {Threshold extraction in metabolite concentration data}, year = {2003}, language = {en} } @article{DelgrandeSchaubTompitsetal.2002, author = {Delgrande, James Patrick and Schaub, Torsten H. 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} }