Robert Weida and Diane Litman. Subsumption and Recognition of Heterogeneous Constraint Networks. In CAIA94, Proceedings of the Tenth IEEE Conference on Artificial Intelligence for Applications, 1994.  Home/Search   Document Details and Download   Summary   Related Articles   Check

.... syntactic rules, to be used for plan de nitions: C; D C X (decomposition) p; q p X # q Y (temporal agreement) where C X means that C is a step in a plan and the temporal agreement speci es equality constraints between paths of features de ned in di erent steps of a plan (see, e.g. Weida and Litman,1994 ] More formally, we add the following semantic equations to the semantics of the basic description logic [ Artale and Franconi,1994a ] C X) I;S V;t;H = fa 2 dom (X S ) j X S (a) 2 C I;S V;V(X) H g (p X # q Y ) I;S V;t;H = fa 2 dom (X S p I;S V;V(X) H ) dom (Y S ....

Robert Weida and Diane Litman. Subsumption and recognition of heterogeneous constraint networks. In Proceedings of CAIA-94, 1994.

....(dropping the variables in the case of Schmiedel, and Artale and Franconi) 6. Description Logics with Temporal Parts This Section overviews two representative approaches of the internal perspective in adding a temporal dimension to a Description Logic. 6.1. The T Rex System Weida and Litman [45,46] propose T Rex, a loose hybrid integration between Description Logics and temporal constraint networks with the aim of representing and reasoning about plans. Plans are de ned as collections of steps (i.e. actions) together with temporal constraints between their duration. Each step is associated ....

R. Weida and D. Litman, Subsumption and recognition of heterogeneous constraint networks, in Proceedings of CAIA-94, 1994.

....Concept languages are also called Frame Based Description Languages, Term Subsumption Languages, Terminological Logics, Taxonomic Logics or Description Logics. with both existential and universal temporal quantification; Devanbu and Litman, 1991 ] and [ Weida and Litman, 1992 ] and recently [ Weida and Litman, 1994 ] propose a loose hybrid integration between concept languages and respectively regular expressions and constraint networks; Schmiedel, 1990 ] proposes a very expressive but undecidable language with variables and temporal quantifiers; Schild, 1993 ] proposes the embedding of point based ....

Robert Weida and Diane Litman. Subsumption and recognition of heterogeneous constraint networks. In Proceedings of CAIA94, 1994.

....about plans by inferences in the underlying description logic. The system simulates the execution of plans, verifies their applicability in particular situations, and solves tasks of temporal projection. An application of description logics to tasks of plan recognition is developed in T REX [ Weida and Litman, 1994 ] Plans in T REX may contain conditions and iterations as well as non determinism in the form of disjunctive actions. The plan library can be static as well as dynamic in MRL. A static library comprises user predefined typical plans. The system retrieves these plans for reuse, but does not add ....

R. Weida and D. Litman. Subsumption and recognition of heterogeneous constraint networks. In Proceedings of the Tenth IEEE Conference on Artificial Intelligence for Applications. IEEE Press, 1994. 35

....structure which is the ISA class hierarchy of the class expressions. Our model uses this ISA hierarchy for both the type hierarchy and the subset hierarchy. The sorted disjunctive normal form is used in a generalization of the subsumption operation which is usually used in description logics (e.g. [Wei94]) That subsumption is only used for conjunctions, which are the datatypes of objects. Description logics do not usually extend the subsumption to include union and complement operators. A class union operation unions the extents of its subclasses, its invariant is the disjunction of the ....

R. Weida, R. and Litman, D. "Subsumption and Recognition of Heterogeneous Constraint Networks ", The Tenth IEEE Conference on Artificial Intelligence for Applications (CAIA-94).

....brief review of my work on plan recognition. I then proceed to contend that knowledge representation issues are crucial for plan recognition and that description logic, for example, has much to offer. The T REX System My work on the t rex plan recognition system reflects my views [ Weida, 1995; Weida and Litman, 1994; 1992 ] t rex s modular architecture integrates and builds upon an existing description logic system for reasoning about concepts, as well as an existing temporal system. Specifically, it calls upon either k rep [ Mays et al. 1991a ] or classic [ Borgida et al. 1989 ] to manage a taxonomy of ....

....P, else optional if O is consistent with P, else impossible. Observations are consistent with a plan if they can be monotonically updated to instantiate the plan under completeness assumptions about the action and plan taxonomies. Details on t rex s consistency inferences are found in [ Weida and Litman, 1994; 1992 ] An enhanced treatment is forthcoming [ Weida, 1995 ] A t rex system diagram appears in Figure 2. When a plan is defined, t rex checks its syntax, normalizes the definition, completes it by deriving implicit information, and finally classifies it in the plan library by means of ....

R. Weida and D. Litman. Subsumption and recognition of heterogeneous constraint networks. In The Tenth Conference on Artificial Intelligence for Applications, pages 381--388. IEEE Computer Society, 1994.

....by inferences in the underlying terminological logic. The system simulates the execution of plans, verifies the applicability of plans in particular situations and solves tasks of temporal projection. An application of terminological logics to tasks of plan recognition is developed in T REX [ Weida and Litman, 1994 ] Plans in T REX may contain conditions and iterations as well as non determinism in the form of disjunctive actions. More complex application domains may require the integration of more expressive terminological logics into the hybrid representation formalism for case libraries. A future ....

R. Weida and D. Litman. Subsumption and recognition of heterogeneous constraint networks. In Proceedings of the Tenth IEEE Conference on Artificial Intelligence for Applications, 1994. to appear.

....be undecidable, at least for most interesting classes of temporal structures: One gets decidability only in very restricted cases, such as when the set of temporal models considered is a finite collection of structures, each consisting of a finite set of natural numbers. Halpern Shoham, 1991) Weida and Litman (1992, 1994) propose T Rex, a loose hybrid integration between Description Logics and constraint networks. Plans are defined as collections of steps together with temporal constraints between their duration. Each step is associated with an action type, represented by a generic concept in K Rep a ....

Weida, R., & Litman, D. (1994). Subsumption and recognition of heterogeneous constraint networks. In Proceedings of CAIA-94.

....(3) appropriately restrict future choices, and (4) characterize the most general choices available for refining a particular individual s description. Thus, we can help focus the efforts of both user and configuration engine. This work evolved from DL based plan recognition in the T REX system (Weida Litman 1994; 1992) It is implemented in the K REP DL system (Mays, Dionne, Weida 1991) Further details, including proofs of theorems, are provided in (Weida 1996) Configuration System Configuration Engine Description Logic System Configuration KB Figure 1: Configuration System Architecture In ....

....National Conference on Artificial Intelligence (AAAI 96) Copyright c fl1996, AAAI. 8 internal KB consistency. However, no previous work has pursued CTA reasoning in DL. This work draws on a predictive recognition methodology for constraint networks representing rich temporal patterns, e.g. plans (Weida Litman 1992; 1994; Weida 1996) Our terminology partitioning algorithm bears some resemblance to the candidate elimination algorithm of (Mitchell 1982) however candidate elimination uses explicit negative examples to exclude concepts, while we derive the concepts to be excluded using CTA. Also, ....

Weida, R., and Litman, D. 1994. Subsumption and recognition of heterogeneous constraint networks. In CAIA-94, 381--388.

.... reasoning and predictive recognition in standard description logic [Weida, 1996] are implemented as an extension to the k rep system [Mays et al. 1991a] Reasoning with plan descriptions and predictive plan recognition are both implemented in the t rex system [Weida 8 and Litman, 1992; Weida and Litman, 1994; Weida, 1995b] To date, t rex is the only system to harness a description logic system, a choice of either k rep or classic [Borgida et al. 1989] in tandem with a powerful temporal reasoner, mats [Kautz and Ladkin, 1991] Further details on the contributions of this thesis are introduced in ....

....and description logic. This work is implemented in the trex system. We have presented examples from the domain of travel plans. Other domains can be addressed as well, including cooking plans (recipes) in [Weida and Litman, 1992] and patterns of error conditions in Automated Teller (ATM) machines [Weida and Litman, 1994] . There are many interesting and challenging directions along which this work can be further developed. 209 Chapter 6 Related Work This chapter places our work in the context of related research. We compare and contrast our results with the most closely related contributions from the literature ....

R. Weida and D. Litman. Subsumption and recognition of heterogeneous constraint networks. In The Tenth Conference on Artificial Intelligence for Applications, pages 381--388. IEEE Computer Society, 1994.

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Robert Weida and Diane Litman. Subsumption and Recognition of Heterogeneous Constraint Networks. In CAIA94, Proceedings of the Tenth IEEE Conference on Artificial Intelligence for Applications, 1994.

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