Property path is the latest navigational extension of the standard query language SPARQL 1.1 for the Semantic Web.However,in the existing SPARQL query systems which support property path,the query efficiency is very l...Property path is the latest navigational extension of the standard query language SPARQL 1.1 for the Semantic Web.However,in the existing SPARQL query systems which support property path,the query efficiency is very low and does not support reasoning.This paper proposes a new existential semantics which has polynomial-time evaluation complexity and an equivalent relationship with the current semantics,and transforms the property path expressions to the extended nested regular expressions based on the existential semantics and proves the semantic equivalence after the transformation considering the RDFS semantics.The property path query engine is achieved by implementing the nested regular expressions algorithm and the transformation rules from the property path expressions to the nested regular expressions,which maintains the syntax simplicity of property path and the goal-oriented polynomial-time reasoning to avoid computing the RDF graph closure.The experiment results not only show the characteristics of query engine based on the existential semantics in efficiency and reasoning,but also further validate the equivalence between the results based on current semantics and those based on the existential semantics for property path after the removal of duplicate values.展开更多
We in this paper give a decomposition concerning the general matrix triplet over an arbitrary divisionring F with the same row or column numbers. We also design a practical algorithm for the decomposition of thematrix...We in this paper give a decomposition concerning the general matrix triplet over an arbitrary divisionring F with the same row or column numbers. We also design a practical algorithm for the decomposition of thematrix triplet. As applications, we present necessary and suficient conditions for the existence of the generalsolutions to the system of matrix equations DXA = C1, EXB = C2, F XC = C3 and the matrix equation AXD + BY E + CZF = Gover F. We give the expressions of the general solutions to the system and the matrix equation when thesolvability conditions are satisfied. Moreover, we present numerical examples to illustrate the results of thispaper. We also mention the other applications of the equivalence canonical form, for instance, for the compressionof color images.展开更多
基金Supported by National Natural Science Foundation of China(No. 61070202 and No. 61100049)
文摘Property path is the latest navigational extension of the standard query language SPARQL 1.1 for the Semantic Web.However,in the existing SPARQL query systems which support property path,the query efficiency is very low and does not support reasoning.This paper proposes a new existential semantics which has polynomial-time evaluation complexity and an equivalent relationship with the current semantics,and transforms the property path expressions to the extended nested regular expressions based on the existential semantics and proves the semantic equivalence after the transformation considering the RDFS semantics.The property path query engine is achieved by implementing the nested regular expressions algorithm and the transformation rules from the property path expressions to the nested regular expressions,which maintains the syntax simplicity of property path and the goal-oriented polynomial-time reasoning to avoid computing the RDF graph closure.The experiment results not only show the characteristics of query engine based on the existential semantics in efficiency and reasoning,but also further validate the equivalence between the results based on current semantics and those based on the existential semantics for property path after the removal of duplicate values.
基金supported by National Natural Science Foundation of China (GrantNo. 60672160)the Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20093108110001)+3 种基金the Scientific Research Innovation Foundation of Shanghai Municipal Education Commission (Grant No. 09YZ13)the Netherlands Organization for Scientific Research (NWO)Singapore MoE Tier 1 Research Grant RG60/07Shanghai Leading Academic Discipline Project (Grant No. J50101)
文摘We in this paper give a decomposition concerning the general matrix triplet over an arbitrary divisionring F with the same row or column numbers. We also design a practical algorithm for the decomposition of thematrix triplet. As applications, we present necessary and suficient conditions for the existence of the generalsolutions to the system of matrix equations DXA = C1, EXB = C2, F XC = C3 and the matrix equation AXD + BY E + CZF = Gover F. We give the expressions of the general solutions to the system and the matrix equation when thesolvability conditions are satisfied. Moreover, we present numerical examples to illustrate the results of thispaper. We also mention the other applications of the equivalence canonical form, for instance, for the compressionof color images.
