Truth Maintenance Systems PDF Download

Author: Joao P. Martins
Publisher:
ISBN: 9783662204542
Category :
Languages : en
Pages : 194

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Author: David F. McAllister
Publisher:
ISBN:
Category :
Languages : en
Pages : 126

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Author: Jon Doyle
Publisher:
ISBN:
Category :
Languages : en
Pages : 45

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To choose their actions, reasoning programs must be able to make assumptions and subsequently revise their beliefs when discoveries contradict these assumtions. The Truth Maintenance System (TMS) is a problem solver subsystem for performing these functions by recording and maintaining the reasons for program beliefs. Such recorded reasons are useful in constructing explanations for program actions and in guiding the course of action of a problem solver. This paper describes (1) the representations and structure of the TMS, (2) the mechanisms used to revise the current set of beliefs, (3) how dependency-directed backtracking changes the current set of assumptions, (4) techniques for summarizing explanations of beliefs, (5) how to organize problem solvers into 'dialectically arguing' modules, (6) how to revise models of the belief systems of others, and (7) methods for embedding control structures in patterns of assumptions. We stress the need of problem solvers to choose between alternate systems of beliefs, and outline a mechanism by which a problem solver can employ rules guiding choices of what to believe, what to want, and what to do. (Author).

Author: João P. Martins
Publisher: Springer Science & Business Media
ISBN: 9783540543053
Category : Computers
Languages : en
Pages : 196

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The Truth Maintenance Workshop was held in August 1990 during the European Conference on Artificial Intelligence in Stockholm, Sweden. Ten selected papers, eight of them presented at the workshop, are included in this volume. The papers can be grouped into four main areas: - Meta-level control: the goal here is to specify some meta-criteria to control the behavior of the TMS. - Extensions of TMS: here the aim is to incorporate new mechanisms into TMS-like systems. - Foundations: there is now much interest in providing formal descriptions of TMS, proving results about them, and relating them with other non-monotonic formalisms. - Belief revision: TMS can be considered as providing support to manage the more general problem of belief revision.

Author: David A. McAllester
Publisher:
ISBN:
Category : Artificial intelligence
Languages : en
Pages : 32

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Truth maintenace systems have been used in recently developed problem solving systems. A truth maintenance system (TMS) is designed to be used by deductive systems to maintain the logical relations among the beliefs which those systems manipulate. These relations are used to incrementally modify the belief structure when premises are changed, giving a more flexible context mechanism than has been present in earlier artificial intelligence systems. The relations among beliefs can also be used to directly trace the source of contradictions or failures, resulting in far more efficient backtracking. In this paper a new approach is taken to truth maintenance algorithms. Each belief, or proposition, can be in any one of three truth states, true, false, or unknown. The relations among propositions are represented in disjunctive classes. By representing an implication in a clause the same algorithm that is used to deduce its consequent can be used to deduce the negation of antecedents that would lead to contradictions. A simple approach is also taken to the handling of assumptions and back tracking which does not involve the non-monotonic dependency structures present in other truth maintenance systems. (Author).

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

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Author: David A. McAllester
Publisher:
ISBN:
Category : Automatic theorem proving
Languages : en
Pages : 44

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Truth maintenance systems (TMS) have been used in several recent problem-solving systems to record justifications for deduced assertions, to track down the assumptions which underlie contradictions when they arise, and to incrementally modify assertional data structures when assumptions are retracted. This report describes a TMS algorithm that is substantially different from previous systems. This algorithm performs deduction in traditional propositional logic in such a way that the premise set from which deduction is being done can be easily manipulated. A novel approach is also taken to the role of a TMS in larger deductive systems. In this approach the TMS performs all propositional deduction in a uniform manner while the larger system is responsible for controlling the instantiation of universally quantified formulae and axiom schemas.

Author: Brian Falkenhainer
Publisher:
ISBN:
Category : Artificial intelligence
Languages : en
Pages : 30

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This paper addresses the problem of probabilistic reasoning as it applies to Truth Maintenance Systems. A Belief Maintenance System has been constructed which manages a current set of probabilistic beliefs in much the same way that a TMS manages a set of true/false beliefs. Such a system may be thought of as a generalization of a Truth Maintenance System. It enables one to reason using normal two or three-valued logic or using probabilistic values to represent partial belief. The design of the Belief Maintenance System is described and some problems are discussed which require further research. Finally, some examples are presented, which show the utility of such a system. Keywords: Problem solving, Artificial intelligence.

Author: Jon Doyle
Publisher:
ISBN:
Category : Problem solving
Languages : en
Pages : 32

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Many procedurally-oriented problem solving systems can be viewed as performing a mixture of computation and deduction, with much of the computation serving to decide what deductions should be made. This results in bits and pieces of deductions being strewn throughout the program text and execution. This paper describes a problem solver subsystem called a truth maintenance system which collects and maintains these bits of deductions. Automatic functions of the thruth maintenance system then use these pieces of 'proofs' to consistently update a data base of program beliefs and to perform a powerful form of backtracking called dependency-directed backtracking. (Author).

Author: Barbara Smith
Publisher:
ISBN:
Category : Computers
Languages : en
Pages : 184

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