Research On Web Services Composition Based On Model-driven

Web service composition techniques used to fulfill users' complex function request by integrating several single services with a specific order. As there are so many composition standards but with no uniform standard, it increases the complexity of service composition and impede technological communication, composition re-use and development. Moreover, the existing standards are not suitable for humans because they are written in XML syntax without an intuitive view. At the same time, the existing service models must be extended to fulfill some special functions required by some special applications.This paper analysis service composition based on model-driven and explains the method in detail. With a core of model, model driven method separates the design process from the special implementation standards by build platform-independent models and platform-dependent model, and it is easy to solve many ills brought by so many composition standards. On the other hand, UML (Unified Modeling Language) used for modeling is suitable for people, as it has many clear diagrams for modeling. In this paper, an example named e-travel is addressed to explain the implementation process of model-driven method in detail.This paper analyzes the Web services'availability and applicability to be used as a kind of Software Framework for functional performance, data management and information exchange of IOT (Internet of Things), and proposes a mapping between things and services. To solve the special problem that the existing WSDL (Web Service Description Language) model cannot describe a thing completely, this paper gives a role-oriented WSDL extension by introducing some concepts of background, role and property. The extension is carried out as a metamodel transformation, according to principles and standards recommended by MDA (Model Driven Architecture).This paper analyzes the utilization and appraisement of QoS (quality of service) in service composition and presents the concept of overall best QoS of service composition, as the composition QoS evaluation should be based on QoS of sub-services and the logical structure of composition. It is pointed out that there is a bottleneck in the calculation of service execution time under the parallel structure, and a QoS-aware service composition optimization based on logical structure is introduced by using this feature to get an overall best QoS composition result.