基于动态QoS的Web服务选取方法

Web Service Selection Method Based on Dynamic QoS

针对动态环境中Web服务QoS属性值波动的问题,提出一种基于动态QoS的服务选取方法。该方法首先建立区间QoS模型来表示QoS属性值的动态变化,然后用区间相似度衡量候选服务提供的QoS属性与用户需求值的接近程度。基于相似度的概念,采用逼近理想点的多属性决策方法计算出每个基本服务的QoS指标客观权重,并结合用户主观偏好得出QoS指标综合权重,最终基于推荐度对候选服务进行排序。仿真实验表明,此服务选取方法既充分考虑了用户的主观偏好,又克服了Web服务QoS属性值的波动影响,提高了服务选取的准确性。

In order to deal with the Quality of Services（QoS）value fluctuations of Web services in dynamic environ- ment,a service selection method based on dynamic QoS was proposed. Firstly, the method establishes an interval QoS model to represent the dynamic changes of QoS values. Then it uses the interval similarities to measure the proximity of the QoS values provided by candidate services to the QoS requirement values provided by consumers. Based on the con- cept of similarity, the objective weight of QoS criteria for each basic service is calculated using TOPSlS（Technique for Order Preference by Similarity to Ideal Solution）method for MADM（Multiple Attribute Decision Making）problems. Af- ter calculating the comprehensive weight by combining with the consumers＇ subjective preference,recommendations are used to sort the candidate services. The experimental results show that this service selection method not only considers the consumers~ subjective preference, but also overcomes the impact of fluctuations in QoS values of Web services, and enhances the correctness of service selection.