Results 1  10
of
30
Embracing Causality in Specifying the Indirect Effects of Actions
, 1995
"... This paper considers the problem of specifying the effects of actions in the situation calculus using domain constraints. We argue that normal state constraints that refer to only the truth values of fluents are not strong enough for this purpose, and that a notion of causation needs to be employed ..."
Abstract

Cited by 179 (10 self)
 Add to MetaCart
This paper considers the problem of specifying the effects of actions in the situation calculus using domain constraints. We argue that normal state constraints that refer to only the truth values of fluents are not strong enough for this purpose, and that a notion of causation needs to be employed explicitly. Technically, we introduce a new ternary predicate Caused into the situation calculus: Caused(p; v; s) if the proposition p is caused (by something unspecified) to have the truth value v in the state s. Using this predicate, we can represent not only actiontriggered causal statements such as that the action load causes the gun to be loaded, but also fluenttriggered ones such as that the fact that the switch is in the up position causes the lamp to be on. The former is convenient for representing the direct effects of actions, and the latter the indirect effects. 1 Introduction We consider the problem of formalizing the effects of actions in the situation calculus [ McCarthy a...
Answer Set Programming and Plan Generation
 ARTIFICIAL INTELLIGENCE
, 2002
"... The idea of answer set programming is to represent a given computational problem by a logic program whose answer sets correspond to solutions, and then use an answer set solver, such as smodels or dlv, to find an answer set for this program. Applications of this method to planning are related to the ..."
Abstract

Cited by 137 (5 self)
 Add to MetaCart
The idea of answer set programming is to represent a given computational problem by a logic program whose answer sets correspond to solutions, and then use an answer set solver, such as smodels or dlv, to find an answer set for this program. Applications of this method to planning are related to the line of research on the frame problem that started with the invention of formal nonmonotonic reasoning in 1980.
Nonmonotonic Reasoning in the Framework of Situation Calculus
 Artificial Intelligence
, 1991
"... Most of the solutions proposed to the Yale shooting problem have either introduced new nonmonotonic reasoning methods (generally involving temporal priorities) or completely reformulated the domain axioms to represent causality explicitly. This paper presents a new solution based on the idea that si ..."
Abstract

Cited by 132 (0 self)
 Add to MetaCart
Most of the solutions proposed to the Yale shooting problem have either introduced new nonmonotonic reasoning methods (generally involving temporal priorities) or completely reformulated the domain axioms to represent causality explicitly. This paper presents a new solution based on the idea that since the abnormality predicate takes a situational argument, it is important for the meanings of the situations to be held constant across the various models being compared. This is accomplished by a simple change in circumscription policy: when Ab is circumscribed, Result (rather than Holds) is allowed to vary. In addition, we need an axiom ensuring that every consistent situation is included in the domain of discourse. Ordinary circumscription will then produce the intuitively correct answer. Beyond its conceptual simplicity, the solution proposed here has additional advantages over the previous approaches. Unlike the approach that uses temporal priorities, it can support reasoning backward...
A Circumscriptive Calculus of Events
 Artificial Intelligence
, 1995
"... A calculus of events is presented in which domain constraints, concurrent events, and events with nondeterministic effects can be represented. The paper offers a nonmonotonic solution to the frame problem for this formalism that combines two of the techniques developed for the situation calculus, ..."
Abstract

Cited by 68 (11 self)
 Add to MetaCart
A calculus of events is presented in which domain constraints, concurrent events, and events with nondeterministic effects can be represented. The paper offers a nonmonotonic solution to the frame problem for this formalism that combines two of the techniques developed for the situation calculus, namely causal and statebased minimisation. A theorem is presented which guarantees that temporal projection will not interfere with minimisation in this solution, even in domains with ramifications, concurrency, and nondeterminism. Finally, the paper shows how the formalism can be extended to cope with continuous change, whilst preserving the conditions for the theorem to apply. 1 Introduction The frame problem was first described by McCarthy and Hayes in the Sixties [23], and has occupied the thoughts of AI researchers ever since. In a nutshell, the problem is this: if we deploy classical logic in a straightforward way to describe the effects of actions, we have to represent explicitl...
A Simple Solution to the Yale Shooting Problem
, 1989
"... Most of the solutions proposed to the Yale shooting problem have either introduced new nonmonotonic reasoning methods (generally involving temporal priorities) or completely reformulated the domain axioms to represent causality explicitly. This paper presents a new solution based on the idea that si ..."
Abstract

Cited by 51 (3 self)
 Add to MetaCart
Most of the solutions proposed to the Yale shooting problem have either introduced new nonmonotonic reasoning methods (generally involving temporal priorities) or completely reformulated the domain axioms to represent causality explicitly. This paper presents a new solution based on the idea that since the abnormality predicate takes a situational argument, it is important for the meanings of the situations to be held constant across the various models being compared. This is accomplished by a simple change in circumscription policy: when Ab is circumscribed, Result (rather than Holds) is allowed to vary. In addition, we need an axiom ensuring that every consistent situation is included in the domain of discourse. Ordinary circumscription will then produce the intuitively correct answer. Beyond its conceptual simplicity, the solution proposed here has additional advantages over the previous approaches. Unlike the approach that uses temporal priorities, it can support reasoning backwar...
Provably Correct Theories of Action
, 1991
"... We investigate logical formalization of the effects of actions in the situation calculus. We propose a formal criterion against which to evaluate theories of deterministic actions. We show how the criterion provides us a formal foundation upon which to tackle the frame problem, as well as its varian ..."
Abstract

Cited by 46 (1 self)
 Add to MetaCart
We investigate logical formalization of the effects of actions in the situation calculus. We propose a formal criterion against which to evaluate theories of deterministic actions. We show how the criterion provides us a formal foundation upon which to tackle the frame problem, as well as its variant in the context of concurrent actions. Our main technical contributions are in formulating a wide class of monotonic causal theories that satisfy the criterion, and showing that each such theory can be reformulated succinctly in circumscription. 1 1 Introduction The histories of the frame problem [18], and of the particular Yale Shooting Problem (YSP) which has become its best known illustration [6], have followed a disturbing pattern. The frame problem itself, although introduced in the context of formalizing common sense, was never formally defined, and was only illustrated through suggestive examples. This is an initial disturbing factor. A second disturbing factor is that, despite the ...
A Survey on Temporal Reasoning in Artificial Intelligence
, 1994
"... The notion of time is ubiquitous in any activity that requires intelligence. In particular, several important notions like change, causality, action are described in terms of time. Therefore, the representation of time and reasoning about time is of crucial importance for many Artificial Intelligenc ..."
Abstract

Cited by 42 (4 self)
 Add to MetaCart
The notion of time is ubiquitous in any activity that requires intelligence. In particular, several important notions like change, causality, action are described in terms of time. Therefore, the representation of time and reasoning about time is of crucial importance for many Artificial Intelligence systems. Specifically during the last 10 years, it has been attracting the attention of many AI researchers. In this survey, the results of this work are analysed. Firstly, Temporal Reasoning is defined. Then, the most important representational issues which determine a Temporal Reasoning approach are introduced: the logical form on which the approach is based, the ontology (the units taken as primitives, the temporal relations, the algorithms that have been developed,. . . ) and the concepts related with reasoning about action (the representation of change, causality, action,. . . ). For each issue the different choices in the literature are discussed. 1 Introduction The notion of time i...
Active Logics: A Unified Formal Approach to Episodic Reasoning
"... Artificial intelligence research falls roughly into two categories: formal and implementational. This division is not completely firm: there are implementational studies based on (formal or informal) theories (e.g., CYC, SOAR, OSCAR), and there are theories framed with an eye toward implementabili ..."
Abstract

Cited by 35 (2 self)
 Add to MetaCart
Artificial intelligence research falls roughly into two categories: formal and implementational. This division is not completely firm: there are implementational studies based on (formal or informal) theories (e.g., CYC, SOAR, OSCAR), and there are theories framed with an eye toward implementability (e.g., predicate circumscription). Nevertheless, formal /theoretical work tends to focus on very narrow problems (and even on very special cases of very narrow problems) while trying to get them "right" in a very strict sense, while implementational work tends to aim at fairly broad ranges of behavior but often at the expense of any kind of overall conceptually unifying framework that informs understanding. It is sometimes urged that this gap is intrinsic to the topic: intelligence is not a unitary thing for which there will be a unifying theory, but rather a "society" of subintelligences whose overall behavior cannot be reduced to useful characterizing and predictive principles.
Temporal projection and explanation
 In Proceedings of the Eleventh International Joint Conference on Artificial Intelligence
, 1989
"... Abstract We propose a solution to problems involving temporal projection and explanation (e.g., the Yale shooting problem) based on the idea that whether a situation is abnormal should not depend upon historical information about how the situation arose. We apply these ideas both to the Yale shootin ..."
Abstract

Cited by 24 (2 self)
 Add to MetaCart
Abstract We propose a solution to problems involving temporal projection and explanation (e.g., the Yale shooting problem) based on the idea that whether a situation is abnormal should not depend upon historical information about how the situation arose. We apply these ideas both to the Yale shooting scenario and to a blocks world domain that needs to address the qualification problem. 1 Introduction The paper [1987] by Hanks and McDermott describing the Yale shooting problem has generated such a flurry of responses that it is difficult to imagine what another one can contribute. The points raised by Hanks and McDermott, both formal and philosophical, have been discussed at substantial length elsewhere.
Two Components of An Action Language
 Annals of Math and AI
, 1996
"... Some of the recent work on representing action makes use of highlevel action languages. In this paper we show that an action language can be represented as the sum of two distinct parts: an "action description language" and an "action query language." A set of propositions in an action description ..."
Abstract

Cited by 19 (5 self)
 Add to MetaCart
Some of the recent work on representing action makes use of highlevel action languages. In this paper we show that an action language can be represented as the sum of two distinct parts: an "action description language" and an "action query language." A set of propositions in an action description language describes the effects of actions on states. Mathematically, it defines a transition system of the kind familiar from the theory of finite automata. An action query language serves for expressing properties of paths in a given transition system. We define the general concepts of a transition system, of an action description language and of an action query language, give a series of examples of languages of both kinds, and show how to combine a description language and a query language into one. This construction makes it possible to design the two components of an action language independently, which leads to the simplification and clarification of the theory of actions. 1 Introducti...