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Applications Of Circumscription To Formalizing Common Sense Knowledge (1986)

by John McCarthy
Venue:Artificial Intelligence
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A Theory of Diagnosis from First Principles

by Raymond Reiter - ARTIFICIAL INTELLIGENCE , 1987
"... Suppose one is given a description of a system, together with an observation of the system's behaviour which conflicts with the way the system is meant to behave. The diagnostic problem is to determine those components of the system which, when assumed to be functioning abnormally, will explain ..."
Abstract - Cited by 1120 (5 self) - Add to MetaCart
Suppose one is given a description of a system, together with an observation of the system's behaviour which conflicts with the way the system is meant to behave. The diagnostic problem is to determine those components of the system which, when assumed to be functioning abnormally, will explain the discrepancy between the observed and correct system behaviour. We propose a general theory for this problem. The theory requires only that the system be described in a suitable logic. Moreover, there are many such suitable logics, e.g. first-order, temporal, dynamic, etc. As a result, the theory accommodates diagnostic reasoning in a wide variety of practical settings, including digital and analogue circuits, medicine, and database updates. The theory leads to an algorithm for computing all diagnoses, and to various results concerning principles of measurement for discriminating among competing diagnoses. Finally, the theory reveals close connections between diagnostic reasoning and nonmonotonic reasoning.

Classical negation in logic programs and disjunctive databases

by Michael Gelfond, Vladimir Lifschitz - New Generation Computing , 1991
"... An important limitation of traditional logic programming as a knowledge representation tool, in comparison with classical logic, is that logic programming does not allow us to deal directly with incomplete information. In order to overcome this limitation, we extend the class of general logic progra ..."
Abstract - Cited by 1044 (73 self) - Add to MetaCart
An important limitation of traditional logic programming as a knowledge representation tool, in comparison with classical logic, is that logic programming does not allow us to deal directly with incomplete information. In order to overcome this limitation, we extend the class of general logic programs by including classical negation, in addition to negation-as-failure. The semantics of such extended programs is based on the method of stable models. The concept of a disjunctive database can be extended in a similar way. We show that some facts of commonsense knowledge can be represented by logic programs and disjunctive databases more easily when classical negation is available. Computationally, classical negation can be eliminated from extended programs by a simple preprocessor. Extended programs are identical to a special case of default theories in the sense of Reiter. 1
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... and which one will be considered negative. In this sense, the language of extended programs is symmetric, like default logic [Reiter1980], autoepistemic logic [Moore1985] and formula circumscription =-=[McCarthy1986]-=-. On the contrary, the modification of our approach proposed in [Kowalski and Sadri1990] is not symmetric. In Section 6 we say more on the use of the closed world assumption in extended programs. Here...

Diagnosing multiple faults.

by Johan De Kleer , Brian C Williams - Artificial Intelligence, , 1987
"... Abstract Diagnostic tasks require determining the differences between a model of an artifact and the artifact itself. The differences between the manifested behavior of the artifact and the predicted behavior of the model guide the search for the differences between the artifact and its model. The ..."
Abstract - Cited by 808 (62 self) - Add to MetaCart
Abstract Diagnostic tasks require determining the differences between a model of an artifact and the artifact itself. The differences between the manifested behavior of the artifact and the predicted behavior of the model guide the search for the differences between the artifact and its model. The diagnostic procedure presented in this paper is model-based, inferring the behavior of the composite device from knowledge of the structure and function of the individual components comprising the device. The system (GDE -General Diagnostic Engine) has been implemented and tested on many examples in the domain of troubleshooting digital circuits. This research makes several novel contributions: First, the system diagnoses failures due to multiple faults. Second, failure candidates are represented and manipulated in terms of minimal sets of violated assumptions, resulting in an efficient diagnostic procedure. Third, the diagnostic procedure is incremental, exploiting the iterative nature of diagnosis. Fourth, a clear separation is drawn between diagnosis and behavior prediction, resulting in a domain (and inference procedure) independent diagnostic procedure. Fifth, GDE combines modelbased prediction with sequential diagnosis to propose measurements to localize the faults. The normally required conditional probabilities are computed from the structure of the device and models of its components. This capability results from a novel way of incorporating probabilities and information theory into the context mechanism provided by AssumptionBased Truth Maintenance.
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...counterfactuals for hypotheticals. Ginsberg’s approaches handles multiple faults, but he does not discuss measurement strategies or probabilities. Both could be integrated into his approach. 6.3 Reiter Reiter13 [32] has been independently exploring many of the ideas incorporated in GDE. His theory of diagnosis provides a formal account of our “intuitive” techniques for conflict recognition and candidate generation. However, his theory does not include a theory of measurements nor how to exploit probabilistic information. 13These results are generalized in [13]. Reiter’s theory uses McCarthy’s [21] AB predicate. Reiter writes ¬AB(A1) (i.e., adder A1 is not ABnormal) while we write A1 (i.e., the assumption that adder A1 is working correctly). Under this mapping, Reiter’s definition of diagnosis is equivalent to our definition of minimal candidate, and his definition of conflict set is equivalent to our definition of conflict. Reiter proposes (unimplemented) a diagnostic algorithm based on his theory. This architecture is quite different from GDE’s. The theorem prover of his architecture corresponds roughly to our inference engine. While GDE’s procedure first computes all minimal conflict...

Representing Action and Change by Logic Programs

by Michael Gelfond, Vladimir Lifschitz - Journal of Logic Programming , 1993
"... We represent properties of actions in a logic programming language that uses both classical negation and negation as failure. The method is applicable to temporal projection problems with incomplete information, as well as to reasoning about the past. It is proved to be sound relative to a semantics ..."
Abstract - Cited by 414 (25 self) - Add to MetaCart
We represent properties of actions in a logic programming language that uses both classical negation and negation as failure. The method is applicable to temporal projection problems with incomplete information, as well as to reasoning about the past. It is proved to be sound relative to a semantics of action based on states and transition functions. 1 Introduction This paper extends the work of Eshghi and Kowalski [6], Evans [7] and Apt and Bezem [1] on representing properties of actions in logic programming languages with negation as failure. Our goal is to overcome some of the limitations of the earlier work. The existing formalizations of action in logic programming are adequate for only the simplest kind of temporal reasoning---"temporal projection." In a temporal projection problem, we are given a description of the initial state of the world, and use properties of actions to determine what the world will look like after a series of actions is performed. Moreover, the existing ...
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... the second---when it is known to be false. The rules (8) play the same role for reasoning "from the future to the past." The auxiliary predicate Noninertial is essentially an "abnormal=-=ity predicate" [22]-=-. Now we will define howstranslates value propositions and effect propositions. The following notation will be useful: For any fluent name F , jF j is F; j:F j is F; and, if t is a situation term, Hol...

Extending and Implementing the Stable Model Semantics

by Patrik Simons, Ilkka Niemelä, Timo Soininen , 2002
"... A novel logic program like language, weight constraint rules, is developed for answer set programming purposes. It generalizes normal logic programs by allowing weight constraints in place of literals to represent, e.g., cardinality and resource constraints and by providing optimization capabilities ..."
Abstract - Cited by 396 (9 self) - Add to MetaCart
A novel logic program like language, weight constraint rules, is developed for answer set programming purposes. It generalizes normal logic programs by allowing weight constraints in place of literals to represent, e.g., cardinality and resource constraints and by providing optimization capabilities. A declarative semantics is developed which extends the stable model semantics of normal programs. The computational complexity of the language is shown to be similar to that of normal programs under the stable model semantics. A simple embedding of general weight constraint rules to a small subclass of the language called basic constraint rules is devised. An implementation of the language, the smodels system, is developed based on this embedding. It uses a two level architecture consisting of a front-end and a kernel language implementation. The front-end allows restricted use of variables and functions and compiles general weight constraint rules to basic constraint rules. A major part of the work is the development of an ecient search procedure for computing stable models for this kernel language. The procedure is compared with and empirically tested against satis ability checkers and an implementation of the stable model semantics. It offers a competitive implementation of the stable model semantics for normal programs and attractive performance for problems where the new types of rules provide a compact representation.
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... the workings of smodels . 1.1 Related Work The stable model semantics is a form of nonmonotonic reasoning that is closely related to the default logic of Reiter [52, 35], circumscription of McCarthy =-=[37, 38, 32]-=-, and the autoepistemic logic of Moore [39, 21]. Since the stable model semantics has become a standard method for supplying semantics to nonmonotonic logic programs, there is a considerable interest ...

Circumscription

by Vladimir Lifschitz , 1996
"... The idea of circumscription can be explained on a simple example. We would like to represent information about the locations of blocks in a blocks world, using the "default": ..."
Abstract - Cited by 340 (9 self) - Add to MetaCart
The idea of circumscription can be explained on a simple example. We would like to represent information about the locations of blocks in a blocks world, using the "default":

Splitting a Logic Program

by Vladimir Lifschitz, Hudson Turner - Principles of Knowledge Representation , 1994
"... In many cases, a logic program can be divided into two parts, so that one of them, the \bottom " part, does not refer to the predicates de ned in the \top " part. The \bottom " rules can be used then for the evaluation of the predicates that they de ne, and the computed va ..."
Abstract - Cited by 294 (16 self) - Add to MetaCart
In many cases, a logic program can be divided into two parts, so that one of them, the \bottom " part, does not refer to the predicates de ned in the \top " part. The \bottom " rules can be used then for the evaluation of the predicates that they de ne, and the computed values can be used to simplify the \top " de nitions. We discuss this idea of splitting a program in the context of the answer set semantics. The main theorem shows how computing the answer sets for a program can be simpli ed when the program is split into parts. The programs covered by the theorem may use both negation as failure and classical negation, and their rules may have disjunctive heads. The usefulness of the concept of splitting for the investigation of answer sets is illustrated by several applications. First, we show that a conservative extension theorem by Gelfond and Przymusinska and a theorem on the closed world assumption by Gelfond and Lifschitz are easy consequences of the splitting theorem. Second, (locally) strati ed programs are shown to have a simple characterization in terms of splitting. The existence and uniqueness of an answer set for such a program can be easily derived from this characterization. Third, we relate the idea of splitting to the notion of order-consistency. 1

A theory of defeasible reasoning

by John L. Pollock , 1991
"... Reasoning can lead not only to the adoption of beliefs, but also to the retraction of beliefs. In philosophy, this is described by saying that reasoning is defeasible. My ultimate objective is the construction of a general theory of reasoning and its implementation in an automated reasoner capable o ..."
Abstract - Cited by 291 (7 self) - Add to MetaCart
Reasoning can lead not only to the adoption of beliefs, but also to the retraction of beliefs. In philosophy, this is described by saying that reasoning is defeasible. My ultimate objective is the construction of a general theory of reasoning and its implementation in an automated reasoner capable of both deductive and defeasible reasoning. The resulting system is named “OSCAR. ” This article addresses some of the theoretical underpinnings of OSCAR. This article extends my earlier theory in two directions. First, it addresses the question of what the criteria of adequacy should be for a defeasible reasoner. Second, it extends the theory to accommodate reasons of varying strengths.

Nonmonotonic Causal Theories

by Enrico Giunchiglia, Joohyung Lee, Vladimir Lifschitz, Norman McCain, Hudson Turner - ARTIFICIAL INTELLIGENCE , 2004
"... The nonmonotonic causal logic defined in this paper can be used to represent properties of actions, including actions with conditional and indirect effects, nondeterministic actions, and concurrently executed actions. It has been applied to several challenge problems in the theory of commonsense kno ..."
Abstract - Cited by 274 (31 self) - Add to MetaCart
The nonmonotonic causal logic defined in this paper can be used to represent properties of actions, including actions with conditional and indirect effects, nondeterministic actions, and concurrently executed actions. It has been applied to several challenge problems in the theory of commonsense knowledge. We study the relationship between this formalism and other work on nonmonotonic reasoning and knowledge representation, and discuss its implementation, called the Causal Calculator.

Disjunctive Datalog

by Thomas Eiter, Georg Gottlob, Heikki Mannila - ACM TRANSACTIONS ON DATABASE SYSTEMS , 1997
"... ..."
Abstract - Cited by 250 (51 self) - Add to MetaCart
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