摘要:

A truth maintenance system is a subsystem that manages the utilization of assumptions in the reasoning process of a problem solver. Doyle's original motivation for creating a truth maintenance system was to augment a reasoning system with a control strategy for activities concerning its nonmonotonic state of beliefs. Hitherto, much effort has been invested in designing and implementing the concept of truth maintenance, and little effort has been dedicated to the formalization that is essential to understanding it. This paper provides a complete formalization of the principle of truth maintenance. Motivated by Reiter and de Kleer's preliminary report on the same subject, this paper extends their study and gives a formal account of the concept of truth maintenance under the general title of assumption‐based reasoning. The concept of assumption‐based theory is defined, and the notions of explanation and direct consequence are presented as forms of plausible conclusions with respect to this theory. Additionally, the concepts of extension and irrefutable sentences are discussed together with other variations of explanation and direct consequence. A set of algorithms for computing these conclusions for a given theory are presented using the notion of prime implicates. Finally, an extended example on Boolean circuit diagnosis is shown to exemplify these id

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00335.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A formal description is given of a connectionist implementation of discrete relaxation for labelled graph matching. The network is shown to converge. The desired behavior of the algorithm is formally specified; then it is proved that the result of the relaxationmeetsthe formal goal. The network is limited by complexity considerations to the detection and propagation of unary and binary consistency constraints. The application is fast parallel indexing into a memory of object models, based on a visually derived junction/link structure description. Implementation experiments are presented, and explicit and exact space and time requirements are developed.

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00336.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Consider the construction of an expert system by encoding the knowledge of different experts. Suppose the knowledge provided by each expert is encoded into a knowledge base. Then the process ofcombiningthe knowledge of these different experts is an important and nontrivial problem. We study this problem here when the expert systems are considered to be first‐order theories. We present techniques for resolving inconsistencies in such knowledge bases. We also provide algorithms for implementing these technique

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00337.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00338.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

This article proposes a framework in which knowledge compilation can be exploited in a principled manner for the task of generating natural language. We have constructed an utterance generator for one side of a realistic dialogue that exploits compiled knowledge of, for instance, the effects of discourse pragmatics on text plans, and the effects of register, style, and politeness on text realization. The motivation for this work is the significant impact that compiled knowledge has on the speed of language generation.

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00339.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

In this paper, I present an architecture for generating extended text. This architecture is implemented in a system, Salix, which incrementally generates natural language texts whose structure is derived from the domain structure of the subject matter. The architecture is composed of data‐driven, domain‐independent strategies for producing increments of text. The strategies include metastrategies that combine or choose among all strategies that are applicable at each increment or decide what to do if no strategy applies. Salix's capabilities are demonstrated in generating texts, in the domains of houses and families, that are comparable to descriptions elicited from human speakers. Salix has also been utilized to generate texts about text style (Germain 1991). The approach to text generation presented here is compared to others in the literature along the dimensions of local organization, coherence, focusing, and domain independence. An argument is made for the approach presented here that locally organizes and incrementally generates coherent t

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00340.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A story generation system based on dynamics of the mind is presented. Semantic theories until now avoided discussing a linkage of language with encyclopedic human knowledge. This paper attacks the problem of how to make clear the complicated, wide‐ranging dynamics of the mind and how to connect it to language.First, the background of this study is shown, in which our model of the mind, with both five levels along the concept formation process and eight domains according to the contents of mental activities, is surveyed.Based on this model, then, the dynamics of mind are discussed, along an Aesop fable. A unit of data processing in the mind is called a “module,” and the mental dynamics are considered as a chain activation of those modules, represented by a dynamic network. Next, a method for story generation is discussed. Propositional information of a sentence is embedded in a slot of activated, frame‐structured modules, and the discourse structure of a generated story basically depends on the dynamic network. Both the chain activation and the generation processes are verified by experiments.Lastly, residual problems of our research, a comparison with related research, and its applications are discussed.This case study would be expected to give a basis to integrated systems for problem solving, natural language and image understandings, their generations, and intelligent

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00341.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Looking to the future, generators will have more knowledge of language and will have to deal with inputs that are very rich in information. As a result, several problems will become more acute, including selecting what to say at the subproposition level and dealing with interaction among goals and dependencies among choices. This paper explains how these problems arise and why they are hard to handle within traditional architectures for generation. It also discusses why these issues have not been well addressed, including the current lack of demanding applications, excessive emphasis on linguistic traditions, the use of reverse engineering to determine generator inputs, and the tendency to research only one issue at a time.

ISSN:0824-7935    

DOI:10.1111/j.1467-8640.1992.tb00342.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY