It is argued that some symmetric structure in logic programs could be taken into account when implementing semantics in logic programming. This may enhance the declarative ability or expressive power of the semantics....It is argued that some symmetric structure in logic programs could be taken into account when implementing semantics in logic programming. This may enhance the declarative ability or expressive power of the semantics. The work presented here may be seen as representative examples along this line. The focus is on the derivation of negative information and some other classic semantic issues. We first define a permutation group associated with a given logic program. Since usually the canonical models used to reflect the common sense or intended meaning are minimal or completed models of the program, we expose the relationships between minimal models and completed models of the original program and its so-called G-reduced form newlt-derived via the permutation group defined. By means of this G reduced form, we introduce a rule to assume negative information termed G-CWA, which is actually a generalization of the GCWA. We also develop the notions of G-definite, G-hierarchical and G-stratified logic programs, which are more general than definite, hierarchical and stratified programs, and extend some well-known declarative and procedural semantics to them, respectively. Keywords symmetry - logic programming - semantics Partially supported by the National Natural Science Foundation of China under Grant No.60373113.Jin-Zhao Wu was born in 1965. He obtained his Ph.D. degree in 1994 from the Institute of Systems Science, the Chinese Academy of Sciences. From 1994 to 1999 he was a post-doctoral and research scientist in Peking University and Max-Planck Institute of Computer Science. Since 2000 he has been working on the Faculty of Mathematics and Computer Science, University of Mannheim.Harald Fecher was born in 1972. He obtained his Ph.D. degree in 2003 from the Faculty of Mathematics and Computer Science, University of Mannheim. Since 2004 he has been research scientist in the Faculty of Computer Science, University of Kiel.展开更多
A new type of intelligent CAI system for chemistry is developed inthis paPer based on automated reaJsoning with chemistry knowledge. The systemhas shown its ability to solve chemistry problems, to assist students and ...A new type of intelligent CAI system for chemistry is developed inthis paPer based on automated reaJsoning with chemistry knowledge. The systemhas shown its ability to solve chemistry problems, to assist students and teachersin studies and instruction with the automated reasoning functions. Its open modeof the knowledge base and its unique style of the illterface between the system andhuman provide more opportunities for the users to acquire living knowledge throughactive participation. The automated reasoning based on basic chemistry knowledgealso opened a new approach to the information storage and management of the ICAIsystem for sciences.展开更多
Action refinement for real-time concurrent processes with urgent interactions is studied, where a partial-order setting, i.e., timed bundle event structures, is used as the system model and a real-time LOTOS-like proc...Action refinement for real-time concurrent processes with urgent interactions is studied, where a partial-order setting, i.e., timed bundle event structures, is used as the system model and a real-time LOTOS-like process algebra is used as the specification language. It is shown that the proposed refinement approaches have the commonly expected properties:(1) the behaviour of the refined process can be inferred compositionally from the behaviour of the original process and from the behaviour of the processes substituted for actions; (2) the timed extensions of pomset (partially ordered multiset) trace equivalence and history preserving bisimulation equivalence are both congruences under the refinement; (3) the syntactic and semantic refinements coincide up to the aforementioned equivalence relations with respect to a cpo-based denotational semantics.展开更多
文摘It is argued that some symmetric structure in logic programs could be taken into account when implementing semantics in logic programming. This may enhance the declarative ability or expressive power of the semantics. The work presented here may be seen as representative examples along this line. The focus is on the derivation of negative information and some other classic semantic issues. We first define a permutation group associated with a given logic program. Since usually the canonical models used to reflect the common sense or intended meaning are minimal or completed models of the program, we expose the relationships between minimal models and completed models of the original program and its so-called G-reduced form newlt-derived via the permutation group defined. By means of this G reduced form, we introduce a rule to assume negative information termed G-CWA, which is actually a generalization of the GCWA. We also develop the notions of G-definite, G-hierarchical and G-stratified logic programs, which are more general than definite, hierarchical and stratified programs, and extend some well-known declarative and procedural semantics to them, respectively. Keywords symmetry - logic programming - semantics Partially supported by the National Natural Science Foundation of China under Grant No.60373113.Jin-Zhao Wu was born in 1965. He obtained his Ph.D. degree in 1994 from the Institute of Systems Science, the Chinese Academy of Sciences. From 1994 to 1999 he was a post-doctoral and research scientist in Peking University and Max-Planck Institute of Computer Science. Since 2000 he has been working on the Faculty of Mathematics and Computer Science, University of Mannheim.Harald Fecher was born in 1972. He obtained his Ph.D. degree in 2003 from the Faculty of Mathematics and Computer Science, University of Mannheim. Since 2004 he has been research scientist in the Faculty of Computer Science, University of Kiel.
文摘A new type of intelligent CAI system for chemistry is developed inthis paPer based on automated reaJsoning with chemistry knowledge. The systemhas shown its ability to solve chemistry problems, to assist students and teachersin studies and instruction with the automated reasoning functions. Its open modeof the knowledge base and its unique style of the illterface between the system andhuman provide more opportunities for the users to acquire living knowledge throughactive participation. The automated reasoning based on basic chemistry knowledgealso opened a new approach to the information storage and management of the ICAIsystem for sciences.
文摘Action refinement for real-time concurrent processes with urgent interactions is studied, where a partial-order setting, i.e., timed bundle event structures, is used as the system model and a real-time LOTOS-like process algebra is used as the specification language. It is shown that the proposed refinement approaches have the commonly expected properties:(1) the behaviour of the refined process can be inferred compositionally from the behaviour of the original process and from the behaviour of the processes substituted for actions; (2) the timed extensions of pomset (partially ordered multiset) trace equivalence and history preserving bisimulation equivalence are both congruences under the refinement; (3) the syntactic and semantic refinements coincide up to the aforementioned equivalence relations with respect to a cpo-based denotational semantics.
