Policy Matching For Web Service Substitution

One of the challenges of the Service-Oriented Architecture is dynamic substitution of one web service with another during the running time. Substitution is conducted based on various criteria. Despite relevant work in the field of substitution, yet no special work has been done for formulating the substitution problem based on adapting policies administered to the qualitative attributes of the service. This article with defining service policy as a set of limitations administered on measurable qualitative attributes, deals with this problem. In this strategy, the administered policies over the services are shown in tree form. To match the policies of various services, the values of the nodes of each tree are compared with their corresponding nodes in the existing services tree, and based on relations defined, the similarity degree of the service is returned. Of the candidate services only those can replace defective services that have an equivalent or compatible similarity degree with them. The proposed algorithm has been conducted on a case study and assessment results show that this method despite previous methods provides for comparing a numerical interval with a fixed number. By clustering compatible services in one cluster decreases search time, and finally expedites substitution and increases interaction among different organizations

Keywords:

Service- oriented architecture , web services , web service substitution , policy-matching , qualitative attributes