Chitta Baral and Michael Gelfond. Representing concurrent actions in extended logic programming. In Proc. IJCAI-93, pages 866--871, 1993.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....trajectories in Trajs(shoot , r) determine the resulting states by assuming that each assignment in the trajectory is performed while no other feature changes its value, e.g. executing shoot in yields =false, alive =false . To encode the Stanford Murder Mystery we use scd 1 = 1]shoot , [1, 2]wait and obs 1 = 0]alive = true, 2]alive = false . Let 1 denote this chronicle. Note that in any case Trajs(shoot , r) contains only a single element as shoot is deterministic. In contrast, each Trajs(spin, r) contains two i.e. we assume complete and accurate knowledge (K) the world ....

....resulting states by assuming that each assignment in the trajectory is performed while no other feature changes its value, e.g. executing shoot in yields =false, alive =false . To encode the Stanford Murder Mystery we use scd 1 = 1]shoot , 1, 2]wait and obs 1 = 0]alive = true, [2]alive = false . Let 1 denote this chronicle. Note that in any case Trajs(shoot , r) contains only a single element as shoot is deterministic. In contrast, each Trajs(spin, r) contains two i.e. we assume complete and accurate knowledge (K) the world acts completely inertial (I ) we consider ....

C. Baral and M. Gelfond. Representing Concurrent Actions in Extended Logic Programming. In R. Bajcsy, ed., Proc. of the IJCAI, p. 866--871,1993.

....Up(l; t) C:Up(l; t 8l; t (Toggle(l; t) Up(l; t) CUp(l; t 8t (Close(t) C:IsOpen(t ) 8t (8l(Up(l; t) CIsOpen(t) Fig. 1. Lin s Suitcase domain in second order UCL language C based on nonpropositional causal theories, and relate C to the action language AC of Baral and Gelfond [3]. 19] also includes an interesting general theorem relating C to Lin s circumscriptive causal action theories, providing yet another perspective on the situation calculus in causal theories. The theorem does not, however, address the question of adequately de ning the Poss predicate, as ....

Chitta Baral and Michael Gelfond. Representing concurrent actions in extended logic programming. In Proc. of IJCAI-93, pages 866-871, 1993. 41

....et al. 29] present a framework for dMARS based on the BDI model. Like us, they assume a state space, and the fact that actions cause state transitions. Labrou and Finin [57] develop the semantics of KQML, but do not explicitly present an action language. Reasoning About Actions. Several works [39, 9, 10, 11] have addressed the problem of modeling the logic of actions by means of logic programming languages. In this section, we briefly address these, one by one. Gelfond and Lifschitz[39] propose a logic programming language called A using which, users may express knowledge about actions and their ....

C. Baral and M. Gelfond. Representing Concurrent Actions in Extended Logic Programming. In 13th Intl. Joint Conf. on Artificial Intelligence, pages 866--871, 1993. 67

....In addition, we have developed an extension of A to model non deterministic actions, and we have integrated this feature too into our equational logic programming based approach. Analogously, we have integrated another extension of the Action Description Language dealing with concurrent actions [6, 9]. Moreover, in [53] the Action Description Language is related to E. Sandewall s so called Ego World Semantics [45, 46] which provides another semantical framework to reason about dynamically changing worlds. The equivalence of a slightly restricted version of A to a particular ontological ....

C. Baral and M. Gelfond. Representing Concurrent Actions in Extended Logic Programming. In R. Bajcsy, editor, Proceedings of the International Joint Conference on Artificial Intelligence (IJCAI), pages 866--871, Chamb'ery, France, Aug. 1993. Morgan Kaufmann.

....multiple servers that have common goals (e.g. provide a police training exercise, or provide a surgical simulation environment) Though we are aware of no direct precursor of this work, it nevertheless draws from and builds upon several areas of research in computer science. First, works such as [11, 6, 7, 5] have addressed the problem of modeling actions and or concurrent actions [7, 5, 4, 3] The key differences between our approach, and this genre of work are the following. First, our approach applies to heterogeneous data sources, while this body of work assumes all data is stored in the form of ....

C. Baral and M. Gelfond. Representing Concurrent Actions in Extended Logic Programming. In 13th Intl. Joint Conf. on Artificial Intelligence, pages 866--871, 1993.

.... On the other hand, several features that have often been neglected by previous work on representation of dynamic systems and reasoning about actions are now receiving attention, because they are needed in practice: e.g. reasoning about the concurrent execution of actions [ Lin and Shoham,1992; Baral and Gelfond,1993 ] sensing actions [ Levesque,1996 ] and exogenous events [ De Giacomo et al. 1997a ] In this paper we follow the approach to the representation of dynamic systems based on PDLs [ Rosenschein,1981 ] and its extension based on the correspondence with Description Logics [ De Giacomo et ....

....Robotics, namely with the goal of implementing it on top of a mobile robot. An analysis of the state of the art in Cognitive Robotics shows that, while several semantic questions concerning the representation of complex dynamic domains have been addressed (see e.g. Lin and Shoham,1992; Baral and Gelfond,1993; Reiter,1996; Pinto,1998 ] for the issue of representing concurrent actions) the problem of generating plans which can be actually executed by a robotic architecture is generally not considered. We thus propose a rich formal setting, where one can deal with sensing actions and concurrent ....

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C Baral and M. Gelfond. Representing concurrent actions in extended logic programming. In Proc. of the 13th Int. Joint Conf. on Artificial Intelligence (IJCAI'93), pages 866--871, 1993.

....T is represented by the literal HoldsAt(Neg(F ) T ) F holds at T is represented by the literal HoldsAt(Pos(F ) T ) The negative literal not HoldsAt(F; T ) is simply interpreted as the t proposition F holds at T is not provable . Similar techniques are also used in [20] 7] 6] and [2]. It is convenient to define translation operators and which convert E fluent literals to program terms such as Pos(F ) and Neg(F ) Definition 19 [lp term and lp complement] Given a fluent literal L of E = h Pi; Delta; Phii, the lp term of L, written (L) is defined to be ffl Pos(F ) if ....

Chitta Baral and Michael Gelfond, Representing Concurrent Actions in Extended Logic Programming, Proceedings IJCAI 93, Morgan Kaufmann, page 866, 1993.

....t) might succeed even when the sub goal HoldsAt(OE i ; t) fails. Were it not for this use of negative literals, the definition of T erminates would in general be incomplete, so that the default persistence of fluents would in general be incorrect. Similar techniques are used for example in [4] and [2]. In fact, in the special case where domains are initially specified these domain specific T erminates clauses may be replaced by a general definition, expressing that an action terminates a fluent if and only if it initiates its converse. The following definition gives a complete translation of ....

....of reasoning about action, various results enable a network of correspondences between formalisms to be built up. For example, Kartha [6] shows a correspondence between Baker s formalism and the Language A introduced in [5] Furthermore, Gelfond and Lifschitz [5] Dung [4] Baral and Gelfond [2], and Denecker and De Schreye [3] have each shown how the Language A can be used as a specification for various logic programming formulations. Like the work in this paper, most results are restricted to cases where theories are fluent independent . ....

Chitta Baral and Michael Gelfond, Representing Concurrent Actions in Extended Logic Programming, Proceedings IJCAI 1993, Morgan Kaufmann, page 866, 1993. 18

....led researchers to enhance it in various ways. Dung [1993] proposed a relational version of A, in which fluents and actions may have arguments. In [Denecker and De Schreye, 1993] and [Thielscher, 1994b] dialects of A are outlined in which one can describe actions with nondeterministic effects. Baral and Gelfond [1993] extend A by an operator for the concurrent execution of a set of actions. The dialect of A defined in [Lifschitz, 1993b] provides symbols for time intervals. 3.7 Discussion The first two translations we provide use first order methods for reasoning about action, whereas the third one uses the ....

Chitta Baral and Michael Gelfond. Representing concurrent actions in extended logic programming. In Proc. of IJCAI-93, pages 866--871, 1993.

....real situation. In order to solve the problems such as SCP, we need to extend the action language A with concurrent actions, and to express incomplete knowledge about the past history. On the other hand, extension of A with concurrent actions has its own right in domain descriptions as argued in [2]. In this paper we will extend A with concurrent actions, but in a different way from that of [2] in the semantics and the translation into logic programs. For representation of incomplete knowledge about the past history we need to extend the action language A. We will introduce a new kind of ....

....A with concurrent actions, and to express incomplete knowledge about the past history. On the other hand, extension of A with concurrent actions has its own right in domain descriptions as argued in [2] In this paper we will extend A with concurrent actions, but in a different way from that of [2] in the semantics and the translation into logic programs. For representation of incomplete knowledge about the past history we need to extend the action language A. We will introduce a new kind of propositions, called observation propositions, whose syntax is as follows: observed F after A 1 ; ....

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Baral, C. and Gelfond, M., Representing concurrent actions in extended logic programming, IJCAI, 1993, 866--871

....from A were also given by Denecker and De Schreye [1993] into the language of abductive logic programming and by Turner [1994] into the language of disjunctive logic programming. 16 Other high level action description languages have been defined as approximate extensions of A; for example, Baral and Gelfond, 1993 ] Kartha and Lifschitz, 1994 ] Thielscher, 1994 ] Giunchiglia and Lifschitz, 1995 ] Giunchiglia et al. 1995 ] Baral et al. 1995 ] and [ Turner, 1997b ] The languages defined in [ Kartha and Lifschitz, 1994 ] and [ Giunchiglia et al. 1995 ] AR 0 and AR, respectively, ....

....whose atoms belong to the signature with respect to which they are defined. 99 The formulas :Up(Left) 0 :Up(Right) 0 Raise(Left) 0 :Raise(Right) 0 oe Spilled 1 :Spilled 0 Raise(Left) 0 Raise(Right) 0 oe :Spilled 1 are consequences of D 7:1 . 5 3 In [ Gelfond et al. 1991b ] Baral and Gelfond, 1993 ] and [ Thielscher, 1995b ] the Soup domain is described essentially as follows: i) the action of raising either side of the bowl causes the soup to be spilled, but (ii) assuming the soup is not already spilled, raising both sides of the bowl concurrently causes it not to be spilled. The ....

Chitta Baral and Michael Gelfond. Representing concurrent actions in extended logic programming. In Proc. of IJCAI-93, pages 866--871, 1993.

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C. Baral and M. Gelfond. Representing concurrent actions in extended logic programming. In Proceedings of the 13th International Joint Conference on Artificial Intelligence, Chambery, France, pages 866--871. Morgan Kaufmann Publishers, San Francisco, CA, 1993.

.... that refers to the same time point, E allows for a limited form of concurrency (its semantics forces the assumption that concurrently performed actions do not interfere, for example to cancel each other s effects) In contrast A does not allow any concurrency, whereas its extension Ac [4] allows for a more general form of concurrency. This principle might be considered too strong for some domains, e.g. those involving continuous change. In this case, some distinction will be required between those properties which naturally persist (frame fluents in Lifschitz s terminology) and ....

....positive literal HoldsAt(Neg(F ) T ) whereas the negative literal not HoldsAt(F; T ) is simply interpreted as the t proposition F holds at T is not provable . In this and other respects, the translation method here is similar to that in [30] Analogous techniques are used in [16] 14] and [4], although not with Event Calculus style programs. Given that our aim is to develop programs able to deal correctly with the form of incompleteness described above, it is useful to first consider incomplete or partial interpretations for a domain description and examine what can be computed ....

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Chitta Baral and Michael Gelfond, Representing Concurrent Actions in Extended Logic Programming, Proceedings IJCAI 93, Morgan Kaufmann, page 866, 1993.

....of L is extended to allow concurrent actions. We will only consider concurrent actions consisting of the simultaneous execution of a finite number of basic actions with noncontradictory effects. For a more sophisticated treatment of concurrent actions in a nonnarrative setting see, e.g. [3] and [28] We will refer to the language with the extended semantics as L c . 8.1. Extended semantics Concurrent actions will be characterized by finite nonempty sets of basic actions. Let us consider the changes that are required in the semantics of L to account for concurrent actions. ....

....issues [14,27] in the workshops AAAI 96 Workshop on Reasoning about actions and AAAI 95 Spring symposium on Extending Theories of Action, and in the recent AAAI, IJCAI and KR conferences. In general, our work has been influenced by the approach of using high level action description languages [3,8,12,16], and their formalization (particularly of AR [16] using nested circumscription. In the previous sections we argued why we believe nested circumscription is an excellent KR language, and listed some of its features. Also, we acknowledge Sandewall s idea of filtering [44] with which NATs has ....

C. Baral, M. Gelfond, Representing concurrent actions in extended logic programming, in: Proc. 13th International Joint Conference on Artificial Intelligence (IJCAI-93), Chambery, France, 1993, pp. 866--871.

....value propositions, whereas AC allows propositional combinations of atomic value propositions. A third difference is that in AR the expression impossible A if is an abbreviation for the effect proposition A causes False if whereas in AC these are distinct propositions. 11 10 An exception is [BG93], which translates the action language AC a language very similar to A but allowing concurrent and non executable actions. But the translation there is similar to the translation of A in [GL93] and exhibits similar shortcomings. 11 We have seen that this distinction becomes convenient when ....

Chitta Baral and Michael Gelfond. Representing concurrent actions in extended logic programming. In Proc. of IJCAI-93, pages 866--871, 1993.

.... similar to that of situation calculus [McC63, MH69] In the last few years the syntax and semantics of A were expanded to allow descriptions of the e ects of concurrent and non deterministic actions as well as descriptions of global constraints expressing time independent relations between uents [BG93, KL94, BT94, Bar95, GL95, BT94, HT93, MT95]. This work can be viewed as complementary to the alternative approach based on direct axiomatizations of theories of actions in classical logic and its nonmonotonic extensions [PR93, Pin94, Rei91, LS91, MS94, Pro96] We believe that both approaches should be developed further before serious ....

.... at airport) after 0 where 0 = pack; drive] 13 One important feature needed for this purpose which is not available in L 1 is the ability to represent and reason about concurrent actions. This restriction is only imposed however to simplify the presentation and can be easily lifted (see [BG93]) 14 Here and in the rest of the paper we use f 1 : f n after at S as an abbreviation for (f 1 after at S) f n after at S) 18 Satis ed with the plan, John packs his suitcase. The execution of this action is recorded by expanding J 0 by the new facts (f4) pack occurs at ....

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C. Baral and M. Gelfond. Representing concurrent actions in extended logic programming. In Proc. of 13th International Joint Conference on Articial Intelligence, pages 866-871, 1993.

....[AB90] and is shown to be sound w.r.t. semantics of A. This work was generalized to achieve complete formalization of domain descriptions in A in the languages of extended logic programs with disjunctions [Tur94] abductive [DDS93, Dun93] and equational logic programming [HT93] respectively. In [BG93] we describe a first attempt at generalizing these programs to the dynamic systems with compound actions. In this paper we extend our approach in [BG93] We hope our work illustrates how the use of action description languages and their semantics facilitates rigorous reasoning about various ....

....languages of extended logic programs with disjunctions [Tur94] abductive [DDS93, Dun93] and equational logic programming [HT93] respectively. In [BG93] we describe a first attempt at generalizing these programs to the dynamic systems with compound actions. In this paper we extend our approach in [BG93]. We hope our work illustrates how the use of action description languages and their semantics facilitates rigorous reasoning about various formalizations, allows to gradually strengthen them, and to investigate the relations between different approaches. The last theme, related to the treatment ....

C. Baral and M. Gelfond. Representing concurrent actions in extended logic programming. In Proc. of 13th International Joint Conference on Artificial Intelligence, Chambery, France, pages 866--871, 1993.

.... papers in [Bro87] which were extremely useful, to general and provenly correct theories [GL93, San92, San94, Rei91, LS91, LS95] that incrementally consider various specification aspects such as: actions with non deterministic effects [Bar95, Pin94, KL94, San93] concurrent actions [LS92, BG93, BG97a] narratives [MS94, PR93, BGP97, BGPml, Kar98] actions with duration [Sho86, San89, San93, San94, MS94, Rei96] natural events [Rei96] ramifications and qualifications due to simple and causal constraints [LR94, KL94, Bar95, Lin97, Thi97, MT95, Lin95, Bar95, GL95, San96, GD96] sensing ....

....; a m;1 ; a m;km ]g, we 11 We often denote this situation by [a1 ; an ]s. 12 denote a compound action, whose execution corresponds to the concurrent execution of the sequences of actions [a 1;1 ; a 1;k1 ] a m;1 ; a m;km ] Compound actions are treated in [BG93, BG97a, LS92, GLR91, ALP94] While, in [BG93, BG97a, LS92, GLR91] concurrent execution of actions are more like parallel execution, in [ALP94] concurrent execution of actions correspond to concurrent transaction processing in databases. When we refer to a plan that achieves a goal, the plan ....

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C. Baral and M. Gelfond. Representing concurrent actions in extended logic programming. In Proc. of 13th International Joint Conference on Artificial Intelligence, Chambery, France, pages 866--871, 1993.

No context found.

Chitta Baral and Michael Gelfond. Representing concurrent actions in extended logic programming. In Proc. IJCAI-93, pages 866--871, 1993.

No context found.

Chitta Baral, Representing concurrent actions in extended logic programming, IJCAI-1993.

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C. Baral and M. Gelfond. Representing Concurrent Actions in Extended Logic Programming. In R. Bajcsy, ed., Proc. of IJCAI, p. 866--871, Chambery, August 1993. Morgan Kaufmann.

No context found.

Baral C., and M. Gelfond, Representing Concurrent Actions in Extended Logic Programming, Proc. of 13th International Joint Conference on Arti cial Intelligence (IJCAI), Chambery, France, Morgan Kaufmann, 866-871, 1993.

No context found.

C. Baral and M. Gelfond. Representing Concurrent Actions in Extended Logic Programming. In R. Bajcsy, ed., Proc. of IJCAI, p. 866--871, Chambery, France, Aug. 1993. Morgan Kaufmann.

No context found.

C. Baral and M. Gelfond. Representing Concurrent Actions in Extended Logic Programming. In R. Bajcsy, editor, Proceedings of the International Joint Conference on Artificial Intelligence (IJCAI), pages 866--871, Chambery, August 1993. Morgan Kaufmann.

No context found.

Chitta Baral and Michael Gelfond, Representing Concurrent Actions in Extended Logic Programming, Proceedings IJCAI 93, Morgan Kaufmann, page 866, 1993.

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