To solve the bottleneck problem in centralized service discovery methods,a novel architecture based on domain ontology for semantic service discovery is proposed.This distributed architecture can adjust the domain partition and allocate system resources automatically.The characteristics of this mechanism are analyzed,including scalability,self-organization and adaptability.In this mechanism,semantic web service discovery is separated into two parts.First,under balance tree topology,registry proxy can rapidly forward requests to the objective registry center,and avoid the bottleneck problem.Secondly,a semantic distance based service matching algorithm is proposed to promote the effect of service searching.The results of simulation experiments show that the proposed mechanism can serve as a scalable solution for semantic web service publication and discovery.And the improved matching algorithm has higher recall and precision than other algorithms.
网格服务质量(QoS)保证是网格环境中最关键的研究内容之一,以往的网格QoS保证机制大多关注于性能QoS的保证,而对于安全QoS鲜有涉及.针对这一不足,提出了用网格安全保护质量(grid quality of protection,GQoP)的概念来定义网格安全QoS,并给出了相应的测量技术.将GQoP看作为网格QoS(GQoS)的一个子类,通过融合模型和协商算法来消除两者之间的资源竞争矛盾,并据此提出了一种具有GQoP保证的网格QoS自适应调度算法.该算法不需要中央节点的控制,而由各资源提供者按照一定的概率分布来调节GQoP和GQoS等级,不仅能够保证用户的GQoP和GQoS需求,而且能够通过构造的马尔可夫链,渐进地逼近系统效用的全局最优解.
