对传感器产生的语义数据流执行复杂推理的能力,最近已成为语义网社区中的重要研究领域,而目前大多数RDF流处理系统是以SPARQL(W3C标准RDF查询语言)为基础实现的,但这些引擎在捕获复杂的用户需求和处理复杂的推理任务方面存在局限性.针...对传感器产生的语义数据流执行复杂推理的能力,最近已成为语义网社区中的重要研究领域,而目前大多数RDF流处理系统是以SPARQL(W3C标准RDF查询语言)为基础实现的,但这些引擎在捕获复杂的用户需求和处理复杂的推理任务方面存在局限性.针对此问题,本文结合并扩展了回答集编程(Answer Set Programing,ASP)技术用于对RDF流进行连续的处理.为了验证本方法的有效性,首先以智能家居本体为实验对象,并分析传感器设备间的共有特性及复杂事件以构建本体库;然后基于本体库产生实例对象,并通过中间件产生RDF数据流;接下来通过扩展ASP,充分利用其表达和推理能力以减少推理时间,并设计了RDF流的窗口划分策略等,然后根据用户的请求,选择性地进行静态知识库加载等;最后通过实验与Sparkwave和Laser进行对比,证明了该方法在延迟和内存上的性能优势.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
This paper described an approach to make inferences on Chinese information using first order predicate logic, which could be used in the semantic query of Chinese. The predicates of the method were derived from the na...This paper described an approach to make inferences on Chinese information using first order predicate logic, which could be used in the semantic query of Chinese. The predicates of the method were derived from the natural language using rule based LFT, the axiom set was generated by extracting lexicon knowledge from HowNet, and the first order predicate inferences were made through symbol connection of center words. After all these were done, the evaluation and possible improvements of the method were provided. The experiment result shows a higher precision rate than that traditional methods can reach.展开更多
A new concept of rare axis based on statistical facts is proposed, and an evaluation algorithm is designed thereafter. For the nested regular expressions containing rare axes, the proposed algorithm can reduce its eva...A new concept of rare axis based on statistical facts is proposed, and an evaluation algorithm is designed thereafter. For the nested regular expressions containing rare axes, the proposed algorithm can reduce its evaluation complexity from polynomial time to nearly linear time. The distributed technique is also employed to construct the navigation axis indexes for resource description framework(RDF) graph data. Experiment results in Drug Bank and Bio GRID show that this method can improve the query efficiency significantly while ensuring the accuracy and meet the query requirements on Web-scale RDF graph data.展开更多
文摘对传感器产生的语义数据流执行复杂推理的能力,最近已成为语义网社区中的重要研究领域,而目前大多数RDF流处理系统是以SPARQL(W3C标准RDF查询语言)为基础实现的,但这些引擎在捕获复杂的用户需求和处理复杂的推理任务方面存在局限性.针对此问题,本文结合并扩展了回答集编程(Answer Set Programing,ASP)技术用于对RDF流进行连续的处理.为了验证本方法的有效性,首先以智能家居本体为实验对象,并分析传感器设备间的共有特性及复杂事件以构建本体库;然后基于本体库产生实例对象,并通过中间件产生RDF数据流;接下来通过扩展ASP,充分利用其表达和推理能力以减少推理时间,并设计了RDF流的窗口划分策略等,然后根据用户的请求,选择性地进行静态知识库加载等;最后通过实验与Sparkwave和Laser进行对比,证明了该方法在延迟和内存上的性能优势.
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.
文摘This paper described an approach to make inferences on Chinese information using first order predicate logic, which could be used in the semantic query of Chinese. The predicates of the method were derived from the natural language using rule based LFT, the axiom set was generated by extracting lexicon knowledge from HowNet, and the first order predicate inferences were made through symbol connection of center words. After all these were done, the evaluation and possible improvements of the method were provided. The experiment result shows a higher precision rate than that traditional methods can reach.
基金Supported by the National Natural Science Foundation of China(No.61373035 and No.61100049)National High Technology Research and Development Program of China("863"Program,No.2013AA013204)+1 种基金Fundamental Research Funds for the Central Universities(No.3122014C018 and 3122015C022)Scientific Research Funds Supported by Civil Aviation University of China(No.09QD02X)
文摘A new concept of rare axis based on statistical facts is proposed, and an evaluation algorithm is designed thereafter. For the nested regular expressions containing rare axes, the proposed algorithm can reduce its evaluation complexity from polynomial time to nearly linear time. The distributed technique is also employed to construct the navigation axis indexes for resource description framework(RDF) graph data. Experiment results in Drug Bank and Bio GRID show that this method can improve the query efficiency significantly while ensuring the accuracy and meet the query requirements on Web-scale RDF graph data.
