Water eutrophication has become a worldwide environmental problem in recent years.Once a water body is eutrophicated,it will lose its primary functions and subsequently influence sustainable development of society and...Water eutrophication has become a worldwide environmental problem in recent years.Once a water body is eutrophicated,it will lose its primary functions and subsequently influence sustainable development of society and economy.Therefore,analysis of eutrophication becomes one of the most essential issues at present.With the ability to deal with vague and uncertain information,and express knowledge in a rule form,the rough set theory(RST) has been widely applied in diverse domains.The advantage of RST is that it can compress the rule and remove needless features by reduction inference rule.By this way,the rule gets effectively simplified and inference efficiency gets improved.However,if data amount is relatively big,it could be a process with large calculated amount to search rules by looking up tables.Petri nets(PNs) possesses so powerful parallel reasoning ability that inference result could be obtained rapidly merely by simple matrix manipulation with no need for searching rules by looking up tables.In this work,an integrated RPN model combining RST with PN was used to analyze relations between degrees of water eutrophication level and influence factors in the Pengxi River of Three Gorges Reservoir.It was shown that the RPN model could analyze water eutrophicaion accurately and quickly,and yield decision rules for the decision-makers at water purification plants of the water quality and assist them in making more cost-effective decisions.展开更多
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
基金Project(2014ZX07104-006)supported by the National Scientific and Technological Major Project of China
文摘Water eutrophication has become a worldwide environmental problem in recent years.Once a water body is eutrophicated,it will lose its primary functions and subsequently influence sustainable development of society and economy.Therefore,analysis of eutrophication becomes one of the most essential issues at present.With the ability to deal with vague and uncertain information,and express knowledge in a rule form,the rough set theory(RST) has been widely applied in diverse domains.The advantage of RST is that it can compress the rule and remove needless features by reduction inference rule.By this way,the rule gets effectively simplified and inference efficiency gets improved.However,if data amount is relatively big,it could be a process with large calculated amount to search rules by looking up tables.Petri nets(PNs) possesses so powerful parallel reasoning ability that inference result could be obtained rapidly merely by simple matrix manipulation with no need for searching rules by looking up tables.In this work,an integrated RPN model combining RST with PN was used to analyze relations between degrees of water eutrophication level and influence factors in the Pengxi River of Three Gorges Reservoir.It was shown that the RPN model could analyze water eutrophicaion accurately and quickly,and yield decision rules for the decision-makers at water purification plants of the water quality and assist them in making more cost-effective decisions.
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.
