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 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 - 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 - 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. 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. 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. 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. 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. 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. 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. 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 - 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 - 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. 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. T1 - Reasoning credulously and skeptically within a single extension Y1 - 2002 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 - Schaub, Torsten H. T1 - Compiling specificity into approaches to nonmonotonic reasoning Y1 - 1997 SN - 0004-3702 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 - A consistency-based framework for merging knowledge bases Y1 - 2007 SN - 1570-8683 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. 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. 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. 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. A1 - Tompits, Hans T1 - A compilation of Brewka and Eiter's approach to prioritizationtion Y1 - 2000 SN - 3-540-41131-3 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - A consistency-based model for belief change: preliminary report Y1 - 2000 SN - 0-262-51112-6 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - Logic programs with compiled preferences Y1 - 2000 SN - 1-58603-013-2 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - Logic programs with compiled preferences Y1 - 2000 UR - http://xxx.lanl.gov/abs/cs.AI/0003028 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. T1 - A consistency-based model for belief change: preliminary report Y1 - 2000 UR - http://xxx.lanl.gov/abs/cs.AI/0003052 ER - TY - JOUR A1 - Delgrande, James Patrick A1 - Schaub, Torsten H. A1 - Tompits, Hans T1 - A compiler for ordered logic programs Y1 - 2000 UR - http://arxiv.org/abs/cs.AI/0003024 ER -