In this paper we firstly extend McCarthy s circumscription to modal logics.Similar to circumscribing predicates,we circumscribe the critical modal operator(the operator to be minimized)in a formula.The modal formulation of circumscription is completely characterized by the minimal model such as the predicate circumscription,The circumscriptive ignorance of the agent s self-knowledge by circumscribing knowledge operator is then illustrated.We further suggest that the merit of circumscription is basic for non…

This paper proposes an approach for functional knowledge representation based on problem reduction,which represents the organization of problem-solving activities in two levels:reduction and reasoning.The former makes the functional plans for problem-solving while the latter constructs functional units, called handlers,for executing subproblems designated by these plans.This approach emphasizes that the representation of domain knowledge should be closely combined with(rather than separated from)its use the…

There have been active work to extend the Prolog style Horn Clause logic programming to non-Horn clauses.In this paper,we will analyze the complexities of several such extensions.The purpose is to understand the computational complexity of these inference systems.The analyses do not prove that any one system is better than the others all the time.But they do suggest that one system may be better than the others for some particular problems.We also discuss the effect of caching.

D-Tuili,having been implemented on microcomputer network,is a distributed logical rea- soning programming language.D-Tuili supports parallel programming on the language level,and couples loosely with the distributed database management system,so data in distributed databases can be used in the distributed logic programs.In this paper,we mainly introduce the components of D-Tuili used to design distributed logic programs.Furthermore,the main principles to imple- ment D-Tuili and the main technologies adopted…

The traditional reasoning system based on first order predicate logic can t represent and handle de- fault knowledge.This paper presents a logical framework representation approach for default reasoning. Based on Mixed SLDNF-resolution,a nonmonotonic reasoning system has been constructed.

In this paper some improvements on certainty factor model are discussed aiming at:1)including, in a rule“E→H”,not only the CF of H when E exists but also CF of(?)when E does not exist(partly or completely).For this purpose another factor(?)is added into the original model;2) improving the model so that it can tackle problems with unknown evidence.In this aspect two concepts are introduced:(relative)maximum existence risk and(relative)maximum non-existence risk.An impor- tant result is that even if some nece…

This paper presents the specification language NUJSL and its supporting system.NUJSL is a modular specification language based on Jackson Program Design Method(JSP).With the module construction,it is convenient to use NUJSL to write larger specifications.The supporting system supports the incremental develop- ment of software specification in NUJSL,and implements the transformation both from specification to software procedural description in Jackson Schematic Logic(pseudo code)and from procedural descripti…

A new probabilistic testability measure is presented to ease test length analyses of random testing and pseudorandom testing.The testability measure given in this paper is oriented to signal conflict of reconvergent fanouts.Test length analyses in this paper are based on a hard fault set,calculations of which are practicable and simple.Experimental results have been obtained to show the accuracy of this test length analyser in comparison with that of Savir,Chin and McCluskey,and Wunderlich by using a pseudo…

A multiple-valued algebra for modeling MOS VLSI circuits at switch-level is proposed in this paper. Its structure and properties are studied.This algebra can be used to transform a MOS digital circuit to a switch-level algebraic expression so as to generate the truth table for the circuit and to derive a Boolean expression for it.In the paper,methods to construct a switch-level algebraic expression for a circuit and methods to simplify expressions are given.This algebra provides a new tool for MOS VLSI circ…

Referring to a set of real time tasks with arriving time,executing time and deadline,this paper discusses the problem of polynomial time initial-allocating approximation algorithms in a distributed system and five new results are gained which provide a theory for the designing of initial-allocating algorithms of real time tasks.

This paper presents a necessary condition for a belief function to be a separable support function,and ne- cessary and sufficient conditions for a belief function with hierarchical focal elements to be decomposed into sim- ple support functions.In the second case,an explicit formula is given for the decomposition.