一种考虑QoS动态变化的服务选择方法

随着Web服务相关技术的高度发展，网络上存在着多个完成相似功能的Web服务。如何选择适合的服务来生成满足用户要求的组合服务成为服务领域的重要研究课题之一。现有的基于服务质量QoS(Quality of Service)的服务选择方法通常都是假定服务提供者发布的QoS数值是真实且固定不变的，然而服务的质量往往在实际运行中 发生变化。为此，针对该问题提出了一种考虑QoS数据动态变化的服务选择方法。该方法引入了QoS分时可靠的思想，将作为选择依据的QoS数值根据以往的服务执行情况给出不同时段上的不同表现数值，这样可以更加贴合地描述服务运行的实际情况。该方法按服务在不同时间段上的可靠性变化划分为不同的子服务，利用冗余的思想在不同的时间段下为用户提供多个满足要求的备选服务。最后通过一组模拟实验说明该方法的可用性和有效性。

Service Selection Approach Considering the Dynamic Change of QoS

With the high development of Web services technology, there are several features similar Web service on Internet. How to select suitable services to meet the needs of customers and generate the service composition has become one of the major issues. Based on the existing QoS service selection method is usually assumed that service provider's value is real and fixed, but the duality of services often changes in the actual operation. Therefore, the paper put forward a dynamic change of data to consider QoS service selection method. The method introduces a reliable QoS sulrperiods,which can be more relevant to describe the actual operation of service. The method according to service at different time changes on the reliability of the subdivided into different services, using redundant, under a different time period to meet the requirements to provide users with multiple options for services. Finally, a simulation experiment shows the availability and effectiveness of the method.