Research On Web Service Complication Selection Algorithm Based On Trust

With the continuous development of network technology and applications, web service as a typical kind of network application form is becoming the cornerstone of the next generation of business application due to the advantages of service interface openness, software resources loose coupling, reusability, interoperability, development language and platform independence. And value-added service composition technology by integrating relatively simple services has become an important way to improve software reusability. But in the open network environment, because of the lack of complex and diverse services resources certification which certificated by professional third-party certification entity, it couldn’t guarantee that the service provided by the participants involved in the interaction and collaboration especially strange service entity is true or reliable. Especially for service composition technology, any of unreliable service entities may lead to the entire service composition uncontrollable. Trust model can help entity establish a reliable Web service environment, reduce the probability of deception by other entities, improve the success rate of service transactions, thus Web service and service composition will be more widely applied. So how to build a suitable trust evaluation model in the network environment and design the service composition selection algorithm based on the trust model have become a hotspot in this research area.To solve the above problems, this paper makes a comprehensive and in-depth research of establishing trust model in Web service environment and selecting of service composition scheme based on trust model. Main works and achievements are as follows:1、It’s certain subjective that current trust models mainly use the users’ feedback information to quantize the trust and identify malicious behavior of entity. This paper presents an approach to calculate the actual capacity of service based on whether the QoS attribute value of interaction between entities reach the scope of the agreement in advance. And the trust model uses the actual service capacity to measure the trust of entity which enhances the objectivity of the evaluation.2、Be aimed at the characteristics of subjectivity,fuzziness and uncertainty of trust in the Web service, a trust modeling method based on the cloud theory was proposed. This paper also presents a relatively complete framework of trust model including the mechanism of trust measurement basis, the formal representation and the inference mechanism of direct trust, recommendation trust and comprehensive trust, the dynamic updating mechanism of trust. To adapt the constantly changing of trust in the network, an updating algorithm based on time weight was advanced. This model is based on the cloud model theory to overcome the shortcoming that a concept must be donated by a precise, the only strict membership function in fuzzy logic. It can evaluate the real level of trust and increase the interaction success rate of entities.3、Researching the service composition selection problem based on trust. Transmitting and merging the each service component’s trust degree and the QoS attributes in the workflow path to calculate the attributes value of entire service composition after the trust model was build. Synthesize these parameters as the basis of selecting service composition scheme. This paper presents an advanced discrete shuffled frog leaping algorithm based on trust that crossing and mutation operations are introduced into the local search. The algorithm can avoid premature phenomenon in the service composition selection; improve the global searching ability and the success rate of entire service composition.