TY  - JOUR
A1  - Anger, Christian
A1  - Gebser, Martin
A1  - Janhunen, Tomi
A1  - Schaub, Torsten H.
T1  - What's a head without a body?
Y1  - 2006
ER  - 
TY  - JOUR
A1  - Anger, Christian
A1  - Gebser, Martin
A1  - Linke, Thomas
A1  - Neumann, Andre
A1  - Schaub, Torsten H.
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  - Gebser, Martin
A1  - Linke, Thomas
A1  - Neumann, Andre
A1  - Schaub, Torsten H.
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  - Gebser, Martin
A1  - Schaub, Torsten H.
T1  - Approaching the core of unfounded sets
Y1  - 2006
UR  - http://www.cs.uni-potsdam.de/wv/pdfformat/angesc06a.pdf
ER  - 
TY  - JOUR
A1  - Anger, Christian
A1  - Konczak, Kathrin
A1  - Linke, Thomas
A1  - Schaub, Torsten H.
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  - Banbara, Mutsunori
A1  - Inoue, Katsumi
A1  - Kaufmann, Benjamin
A1  - Okimoto, Tenda
A1  - Schaub, Torsten H.
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  - Banbara, Mutsunori
A1  - Soh, Takehide
A1  - Tamura, Naoyuki
A1  - Inoue, Katsumi
A1  - Schaub, Torsten H.
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  - Benhammadi, Farid
A1  - Nicolas, Pascal
A1  - Schaub, Torsten H.
T1  - Extension calculus and query answering in prioritized default logic
Y1  - 1998
SN  - 3-540-64993-X
ER  - 
TY  - JOUR
A1  - Benhammadi, Farid
A1  - Nicolas, Pascal
A1  - Schaub, Torsten H.
T1  - Extension calculus and query answering in prioritized default logic
Y1  - 1998
SN  - 3-540- 64993-X
ER  - 
TY  - JOUR
A1  - Benhammadi, Farid
A1  - Nicolas, Pascal
A1  - Schaub, Torsten H.
T1  - Query-answering in prioritized default logic
Y1  - 1999
SN  - 3-540-66131-X
ER  - 
TY  - JOUR
A1  - Benhammadi, Farid
A1  - Nicolas, Pascal
A1  - Schaub, Torsten H.
T1  - Query-answering in prioritized default logic
Y1  - 1999
SN  - 3-540-66131-X
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Fanselow, Gisbert
A1  - Schaub, Torsten H.
T1  - Optimality theory as a family of cumulative logics
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Mercer, Robert E.
A1  - Schaub, Torsten H.
T1  - Optimality theory throught default logic
Y1  - 2003
SN  - 3-540-20059-2
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Mercer, Robert E.
A1  - Schaub, Torsten H.
T1  - Optimality Theory via Default Logic
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - A simple signed system for paraconsistent reasoning
Y1  - 1996
SN  - 3-540-61630-6
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - A context-based framework for default logics
Y1  - 1993
SN  - 0-262-51071-5
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - Signed systems for paraconsistent reasoning
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - Characterization of non-monotone non-constructive systems
Y1  - 1998
SN  - 1012-2443
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - Signed systems for paraconsistent reasoning
Y1  - 1998
SN  - 0168-7433
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - An approach to context-based default reasoning
Y1  - 1995
SN  - 0169-2968
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - Circumscribing inconsistency
Y1  - 1997
SN  - 1-558-60480-4
SN  - 1045-0823
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - Significant inferences
Y1  - 2000
SN  - 1-55860-690-4
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
T1  - What is a (non-constructive) non-monotone logical system?
Y1  - 2000
SN  - 0304-3975
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - Paraconsistent reasoning via quantified boolean formulas
Y1  - 2002
SN  - 3-540-44190-5
ER  - 
TY  - JOUR
A1  - Besnard, Philippe
A1  - Schaub, Torsten H.
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  - Bibel, Wolfgang
A1  - Brüning, Stefan
A1  - Otten, Jens
A1  - Rath, Thomas
A1  - Schaub, Torsten H.
T1  - Compressions and extensions
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Boesel, Andreas
A1  - Linke, Thomas
A1  - Schaub, Torsten H.
T1  - Profiling answer set programming : the visualization component of the noMoRe System
Y1  - 2004
SN  - 3-540-23242-7
ER  - 
TY  - JOUR
A1  - Borchert, P.
A1  - Anger, Christian
A1  - Schaub, Torsten H.
A1  - Truszczynski, M.
T1  - Towards systematic benchmarking in answer set programming : the dagstuhl initiative
Y1  - 2004
SN  - 3-540- 20721-x
ER  - 
TY  - GEN
A1  - Bosser, Anne-Gwenn
A1  - Cabalar, Pedro
A1  - Dieguez, Martin
A1  - Schaub, Torsten H.
T1  - Introducing temporal stable models for linear dynamic logic
T2  - 16th International Conference on Principles of Knowledge Representation and Reasoning
N2  - We propose a new temporal extension of the logic of Here-and-There (HT) and its equilibria obtained by combining it with dynamic logic over (linear) traces. Unlike previous temporal extensions of HT based on linear temporal logic, the dynamic logic features allow us to reason about the composition of actions. For instance, this can be used to exercise fine grained control when planning in robotics, as exemplified by GOLOG. In this paper, we lay the foundations of our approach, and refer to it as Linear Dynamic Equilibrium Logic, or simply DEL. We start by developing the formal framework of DEL and provide relevant characteristic results. Among them, we elaborate upon the relationships to traditional linear dynamic logic and previous temporal extensions of HT.
Y1  - 2018
UR  - https://www.dc.fi.udc.es/~cabalar/del.pdf
SP  - 12
EP  - 21
PB  - ASSOC Association for the Advancement of Artificial Intelligence
CY  - Palo Alto
ER  - 
TY  - JOUR
A1  - Brain, Martin
A1  - Faber, Wolfgang
A1  - Maratea, Marco
A1  - Polleres, Axel
A1  - Schaub, Torsten H.
A1  - Schindlauer, Roman
T1  - What should an ASP solver output? : a multiple position paper
Y1  - 2007
ER  - 
TY  - JOUR
A1  - Brain, Martin
A1  - Gebser, Martin
A1  - Pührer, Jörg
A1  - Schaub, Torsten H.
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  - Brain, Martin
A1  - Gebser, Martin
A1  - Pührer, Jörg
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - Debugging ASP programs by means of ASP
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Brewka, Gerhard
A1  - Ellmauthaler, Stefan
A1  - Kern-Isberner, Gabriele
A1  - Obermeier, Philipp
A1  - Ostrowski, Max
A1  - Romero, Javier
A1  - Schaub, Torsten H.
A1  - Schieweck, Steffen
T1  - Advanced solving technology for dynamic and reactive applications
JF  - Künstliche Intelligenz
Y1  - 2018
U6  - https://doi.org/10.1007/s13218-018-0538-8
SN  - 0933-1875
SN  - 1610-1987
VL  - 32
IS  - 2-3
SP  - 199
EP  - 200
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - GEN
A1  - Brewka, Gerhard
A1  - Schaub, Torsten H.
A1  - Woltran, Stefan
T1  - Interview with Gerhard Brewka
T2  - Künstliche Intelligenz
N2  - This interview with Gerhard Brewka was conducted by correspondance in May 2018. The question set was compiled by Torsten Schaub and Stefan Woltran.
Y1  - 2018
U6  - https://doi.org/10.1007/s13218-018-0549-5
SN  - 0933-1875
SN  - 1610-1987
VL  - 32
IS  - 2-3
SP  - 219
EP  - 221
PB  - Springer
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Brüning, Stefan
A1  - Schaub, Torsten H.
T1  - A model-based approach to consistency-checking
Y1  - 1996
SN  - 3-540-61286-6
ER  - 
TY  - JOUR
A1  - Brüning, Stefan
A1  - Schaub, Torsten H.
T1  - A connection calculus for handling incomplete information
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Brüning, Stefan
A1  - Schaub, Torsten H.
T1  - Avoiding non-ground variables
Y1  - 1999
SN  - 3-540-66131-x
ER  - 
TY  - JOUR
A1  - Brüning, Stefan
A1  - Schaub, Torsten H.
T1  - A voiding non-ground variables
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Cabalar, Pedro
A1  - Dieguez, Martin
A1  - Schaub, Torsten H.
A1  - Schuhmann, Anna
T1  - Towards metric temporal answer set programming
JF  - Theory and practice of logic programming
N2  - We elaborate upon the theoretical foundations of a metric temporal extension of Answer Set Programming. In analogy to previous extensions of ASP with constructs from Linear Temporal and Dynamic Logic, we accomplish this in the setting of the logic of Here-and-There and its non-monotonic extension, called Equilibrium Logic. More precisely, we develop our logic on the same semantic underpinnings as its predecessors and thus use a simple time domain of bounded time steps. This allows us to compare all variants in a uniform framework and ultimately combine them in a common implementation.
Y1  - 2020
U6  - https://doi.org/10.1017/S1471068420000307
SN  - 1471-0684
SN  - 1475-3081
VL  - 20
IS  - 5
SP  - 783
EP  - 798
PB  - Cambridge Univ. Press
CY  - Cambridge [u.a.]
ER  - 
TY  - JOUR
A1  - Cabalar, Pedro
A1  - Fandiño, Jorge
A1  - Garea, Javier
A1  - Romero, Javier
A1  - Schaub, Torsten H.
T1  - Eclingo
BT  - a solver for epistemic logic programs
JF  - Theory and practice of logic programming
N2  - We describe eclingo, a solver for epistemic logic programs under Gelfond 1991 semantics built upon the Answer Set Programming system clingo. The input language of eclingo uses the syntax extension capabilities of clingo to define subjective literals that, as usual in epistemic logic programs, allow for checking the truth of a regular literal in all or in some of the answer sets of a program. The eclingo solving process follows a guess and check strategy. It first generates potential truth values for subjective literals and, in a second step, it checks the obtained result with respect to the cautious and brave consequences of the program. This process is implemented using the multi-shot functionalities of clingo. We have also implemented some optimisations, aiming at reducing the search space and, therefore, increasing eclingo 's efficiency in some scenarios. Finally, we compare the efficiency of eclingo with two state-of-the-art solvers for epistemic logic programs on a pair of benchmark scenarios and show that eclingo generally outperforms their obtained results.
KW  - Answer Set Programming
KW  - Epistemic Logic Programs
KW  - Non-Monotonic
KW  - Reasoning
KW  - Conformant Planning
Y1  - 2020
U6  - https://doi.org/10.1017/S1471068420000228
SN  - 1471-0684
SN  - 1475-3081
VL  - 20
IS  - 6
SP  - 834
EP  - 847
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - JOUR
A1  - Cabalar, Pedro
A1  - Fandiño, Jorge
A1  - Schaub, Torsten H.
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  - GEN
A1  - Cabalar, Pedro
A1  - Fandiño, Jorge
A1  - Schaub, Torsten H.
A1  - Schellhorn, Sebastian
T1  - Lower Bound Founded Logic of Here-and-There
T2  - Logics in Artificial Intelligence
N2  - A distinguishing feature of Answer Set Programming is that all atoms belonging to a stable model must be founded. That is, an atom must not only be true but provably true. This can be made precise by means of the constructive logic of Here-and-There, whose equilibrium models correspond to stable models. One way of looking at foundedness is to regard Boolean truth values as ordered by letting true be greater than false. Then, each Boolean variable takes the smallest truth value that can be proven for it. This idea was generalized by Aziz to ordered domains and applied to constraint satisfaction problems. As before, the idea is that a, say integer, variable gets only assigned to the smallest integer that can be justified. In this paper, we present a logical reconstruction of Aziz’ idea in the setting of the logic of Here-and-There. More precisely, we start by defining the logic of Here-and-There with lower bound founded variables along with its equilibrium models and elaborate upon its formal properties. Finally, we compare our approach with related ones and sketch future work.
Y1  - 2019
SN  - 978-3-030-19570-0
SN  - 978-3-030-19569-4
U6  - https://doi.org/10.1007/978-3-030-19570-0_34
SN  - 0302-9743
SN  - 1611-3349
VL  - 11468
SP  - 509
EP  - 525
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Gharib, Mona
A1  - Mercer, Robert E.
A1  - Risch, V.
A1  - Schaub, Torsten H.
T1  - Lukaszewicz-style answer set programming : a preliminary report
Y1  - 2003
UR  - http://sunsite.informatik.rwth-aachen.de/Publications/CEUR-WS/Vol-78/
SN  - 1613-0073
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Hunter, Anthony
A1  - Schaub, Torsten H.
T1  - COBA: a consistency-based belief revision system
Y1  - 2002
SN  - 3-540-44190-5
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Lang, Jérôme
A1  - Schaub, Torsten H.
T1  - Belief change based on global minimisation
Y1  - 2007
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Liu, Daphne H.
A1  - Schaub, Torsten H.
A1  - Thiele, Sven
T1  - COBA 2.0 : a consistency-based belief change system
Y1  - 2006
UR  - http://www2.in.tu-clausthal.de/~tmbehrens/NMR_Proc_TR4.pdf
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Liu, Daphne H.
A1  - Schaub, Torsten H.
A1  - Thiele, Sven
T1  - COBA 2.0 : a consistency-based belief change system
Y1  - 2007
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Expressing default logic variants in default logic
N2  - 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
Y1  - 2005
SN  - 0955-792X
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Two approaches to merging knowledge bases
Y1  - 2004
SN  - 3-540-23242-7
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Consistency-based approaches to merging knowledge based : preliminary report
Y1  - 2004
UR  - http://www.pims.math.ca/science/2004/NMR/papers/paper17.pdf
SN  - 92-990021-0-X
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Reasoning with sets of preferences in default logic
N2  - 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
Y1  - 2004
SN  - 0824-7935
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Reasoning credulously and skeptically within a single extension
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - On the relation between Reiterïs default logic and its (major) variants
Y1  - 2003
SN  - 3-540- 409494-5
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - A concictency-based paradigm for belief change
Y1  - 2003
SN  - 0004-3702
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Reasoning credulously and skeptically within a single extension
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Compiling specificity into approaches to nonmonotonic reasoning
Y1  - 1997
SN  - 0004-3702
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - A consistency-based framework for merging knowledge bases
Y1  - 2007
SN  - 1570-8683
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Reasoning with sets of preferences in default logic
Y1  - 1998
SN  - 3-540- 65271-x
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Compiling reasoning with and about preferences into default logic
Y1  - 1997
SN  - 1-558-60480-4
SN  - 1045-0823
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - How to reason credulously and skeptically within a single extension.
Y1  - 2001
SN  - 3-540- 42464-4
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - How to reason credulously and skeptically within a single extension
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - The role of default logic in knowledge representation
Y1  - 2000
SN  - 0-7923-7224-7
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - Expressing preferences in default logic
Y1  - 2000
SN  - 0004-3702
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - A consistency-based model for belief change: preliminary report
Y1  - 2000
SN  - 0-262-51112-6
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
T1  - A consistency-based model for belief change: preliminary report
Y1  - 2000
UR  - http://xxx.lanl.gov/abs/cs.AI/0003052
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - A 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  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - A preference-based framework for updating logic programs
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - An Extended Query language for action languages (and its application to aggregates and preferences)
Y1  - 2006
UR  - http://www2.in.tu-clausthal.de/~tmbehrens/NMR_Proc_TR4.pdf
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - Domain-specific preference for causal reasoning and planning
Y1  - 2004
SN  - 1-577-35201-7
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - A framework for compiling preferences in logic programs
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - A general framework for expressing preferences in causal reasoning and planning
N2  - 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.
Y1  - 2007
UR  - http://logcom.oxfordjournals.org/
U6  - https://doi.org/10.1093/logcom/exm046
SN  - 0955-792X
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - A generic compiler for ordered logic programs
Y1  - 2001
SN  - 3-540-42593-4
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - A compilation of Brewka and Eiter's approach to prioritizationtion
Y1  - 2000
SN  - 3-540-41131-3
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - Logic programs with compiled preferences
Y1  - 2000
SN  - 1-58603-013-2
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - Logic programs with compiled preferences
Y1  - 2000
UR  - http://xxx.lanl.gov/abs/cs.AI/0003028
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
T1  - A compiler for ordered logic programs
Y1  - 2000
UR  - http://arxiv.org/abs/cs.AI/0003024
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Wang, Kewen
T1  - A classification and survey of preference handling approchaches in nonmonotonic reasoning
N2  - 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
Y1  - 2004
SN  - 0824-7935
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Wang, Kewen
T1  - Towards a classification of preference handling approaches in nonmonotonic reasoning
Y1  - 2002
SN  - 1-577-35166-5
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - On Computing belief change operations using quantifield boolean formulas
N2  - 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
Y1  - 2004
SN  - 0955-792X
ER  - 
TY  - JOUR
A1  - Delgrande, James Patrick
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - On computing solutions to belief change scenarios
Y1  - 2001
SN  - 3-540- 42464-4
ER  - 
TY  - JOUR
A1  - Delgrande, James
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - A model-theoretic approach to belief change in answer set programming
JF  - ACM transactions on computational logic
N2  - 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.
KW  - Theory
KW  - Answer set programming
KW  - belief revision
KW  - belief merging
KW  - program encodings
KW  - strong equivalence
Y1  - 2013
U6  - https://doi.org/10.1145/2480759.2480766
SN  - 1529-3785
VL  - 14
IS  - 2
PB  - Association for Computing Machinery
CY  - New York
ER  - 
TY  - JOUR
A1  - Dimopoulos, Yannis
A1  - Gebser, Martin
A1  - Lühne, Patrick
A1  - Romero Davila, Javier
A1  - Schaub, Torsten H.
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  - Durzinsky, Markus
A1  - Marwan, Wolfgang
A1  - Ostrowski, Max
A1  - Schaub, Torsten H.
A1  - Wagler, Annegret
T1  - Automatic network reconstruction using ASP
JF  - Theory and practice of logic programming
N2  - Building biological models by inferring functional dependencies from experimental data is an important issue in Molecular Biology. To relieve the biologist from this traditionally manual process, various approaches have been proposed to increase the degree of automation. However, available approaches often yield a single model only, rely on specific assumptions, and/or use dedicated, heuristic algorithms that are intolerant to changing circumstances or requirements in the view of the rapid progress made in Biotechnology. Our aim is to provide a declarative solution to the problem by appeal to Answer Set Programming (ASP) overcoming these difficulties. We build upon an existing approach to Automatic Network Reconstruction proposed by part of the authors. This approach has firm mathematical foundations and is well suited for ASP due to its combinatorial flavor providing a characterization of all models explaining a set of experiments. The usage of ASP has several benefits over the existing heuristic algorithms. First, it is declarative and thus transparent for biological experts. Second, it is elaboration tolerant and thus allows for an easy exploration and incorporation of biological constraints. Third, it allows for exploring the entire space of possible models. Finally, our approach offers an excellent performance, matching existing, special-purpose systems.
Y1  - 2011
U6  - https://doi.org/10.1017/S1471068411000287
SN  - 1471-0684
VL  - 11
SP  - 749
EP  - 766
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - JOUR
A1  - Fandiño, Jorge
A1  - Lifschitz, Vladimir
A1  - Lühne, Patrick
A1  - Schaub, Torsten H.
T1  - Verifying tight logic programs with Anthem and Vampire
JF  - Theory and practice of logic programming
N2  - This paper continues the line of research aimed at investigating the relationship between logic programs and first-order theories. We extend the definition of program completion to programs with input and output in a subset of the input language of the ASP grounder gringo, study the relationship between stable models and completion in this context, and describe preliminary experiments with the use of two software tools, anthem and vampire, for verifying the correctness of programs with input and output. Proofs of theorems are based on a lemma that relates the semantics of programs studied in this paper to stable models of first-order formulas.
Y1  - 2020
U6  - https://doi.org/10.1017/S1471068420000344
SN  - 1471-0684
SN  - 1475-3081
VL  - 20
IS  - 5
SP  - 735
EP  - 750
PB  - Cambridge Univ. Press
CY  - Cambridge [u.a.]
ER  - 
TY  - JOUR
A1  - Flöter, André
A1  - Nicolas, Jacques
A1  - Schaub, Torsten H.
A1  - Selbig, Joachim
T1  - Threshold extraction in metabolite concentration data
N2  - 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
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Flöter, André
A1  - Nicolas, Jacques
A1  - Schaub, Torsten H.
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  - Flöter, André
A1  - Selbig, Joachim
A1  - Schaub, Torsten H.
T1  - Finding metabolic pathways in decision forests
Y1  - 2004
SN  - 3-540-23221-4
ER  - 
TY  - JOUR
A1  - Frioux, Clémence
A1  - Schaub, Torsten H.
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  - JOUR
A1  - Gebser, Martin
A1  - Gharib, Mona
A1  - Mercer, Robert E.
A1  - Schaub, Torsten H.
T1  - Monotonic answer set programming
N2  - 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.
Y1  - 2009
UR  - http://logcom.oxfordjournals.org/
U6  - https://doi.org/10.1093/logcom/exn040
SN  - 0955-792X
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Gharib, Mona
A1  - Schaub, Torsten H.
T1  - Incremental answer sets and their computation
Y1  - 2007
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 H.
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  - Gebser, Martin
A1  - Kaminski, Roland
A1  - Schaub, Torsten H.
T1  - Complex optimization in answer set programming
JF  - Theory and practice of logic programming
N2  - 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.
KW  - Answer Set Programming
KW  - Preference Handling
KW  - Complex optimization
KW  - Meta-Programming
Y1  - 2011
U6  - https://doi.org/10.1017/S1471068411000329
SN  - 1471-0684
VL  - 11
IS  - 3
SP  - 821
EP  - 839
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 H.
A1  - Schneider, Marius
T1  - Potassco the Potsdam answer set solving collection
JF  - AI communications : AICOM ; the European journal on artificial intelligence
N2  - This paper gives an overview of the open source project Potassco, the Potsdam Answer Set Solving Collection, bundling tools for Answer Set Programming developed at the University of Potsdam.
KW  - Answer set programming
KW  - declarative problem solving
Y1  - 2011
U6  - https://doi.org/10.3233/AIC-2011-0491
SN  - 0921-7126
VL  - 24
IS  - 2
SP  - 107
EP  - 124
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Neumann, André
A1  - Schaub, Torsten H.
T1  - Conflict-driven answer set enumeration
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Neumann, André
A1  - Schaub, Torsten H.
T1  - Conflict-driven answer set solving
Y1  - 2007
SN  - 978-1-57735-323-2
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Neumann, André
A1  - Schaub, Torsten H.
T1  - Clasp : a conflict-driven answer set solver
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Schaub, Torsten H.
T1  - Conflict-driven answer set solving: From theory to practice
JF  - Artificial intelligence
N2  - We introduce an approach to computing answer sets of logic programs, based on concepts successfully applied in Satisfiability (SAT) checking. The idea is to view inferences in Answer Set Programming (ASP) as unit propagation on nogoods. This provides us with a uniform constraint-based framework capturing diverse inferences encountered in ASP solving. Moreover, our approach allows us to apply advanced solving techniques from the area of SAT. As a result, we present the first full-fledged algorithmic framework for native conflict-driven ASP solving. Our approach is implemented in the ASP solver clasp that has demonstrated its competitiveness and versatility by winning first places at various solver contests.
KW  - Answer set programming
KW  - Logic programming
KW  - Nonmonotonic reasoning
Y1  - 2012
U6  - https://doi.org/10.1016/j.artint.2012.04.001
SN  - 0004-3702
VL  - 187
IS  - 8
SP  - 52
EP  - 89
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Schaub, Torsten H.
T1  - Multi-threaded ASP solving with clasp
JF  - Theory and practice of logic programming
N2  - We present the new multi-threaded version of the state-of-the-art answer set solver clasp. We detail its component and communication architecture and illustrate how they support the principal functionalities of clasp. Also, we provide some insights into the data representation used for different constraint types handled by clasp. All this is accompanied by an extensive experimental analysis of the major features related to multi-threading in clasp.
Y1  - 2012
U6  - https://doi.org/10.1017/S1471068412000166
SN  - 1471-0684
VL  - 12
IS  - 8
SP  - 525
EP  - 545
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Liu, Lengning
A1  - Namasivayam, Gayathri
A1  - Neumann, André
A1  - Schaub, Torsten H.
A1  - Truszczynski, Miroslaw
T1  - The first answer set programming system competition
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Obermeier, Philipp
A1  - Schaub, Torsten H.
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  -