期刊名称：International Journal of Advanced Computer Science and Applications(IJACSA)
印刷版ISSN：2158-107X
电子版ISSN：2156-5570
出版年度：2016
卷号：7
期号：7
DOI：10.14569/IJACSA.2016.070751
出版社：Science and Information Society (SAI)
摘要：Service-oriented architecture is a style in information systems architecture with the aim of achieving loose coupling in communication between software components and services. Service, here means software implementation, is a well-defined business function that can be used and be called in various processes or software. An organization can choose and composite the Web services that fulfill its intended quality of service. As the number of available Web services increases, choosing the best services to composite is challenging and is the most important problem of service composition. In addition, due to the utilization of systems in dynamic environments, service characteristics and users’ needs are constantly faced with changes which lead to deterioration of service, unavailability and quality loss of services. One of the ways to deal with this challenge is substitution of a Web service with another service, which is done at the runtime and dynamically. Substitution is both direct and indirect. Though there are many related works in the field of direct substitution, still no work is done for explaining substitution based on the indirect method, and works were conducted only on direct substitution. In this method, there are many problems such as the incompatibility of important services in composition. To solve the problems in this method and other challenges in this paper, considering a subset of inputs and outputs, qualitative parameters and service composition, simultaneous and dynamic service composition and use of the fitness function of genetic algorithm to compare the compositions are done. In addition, in substitution, a table which contains the best possible substitutes with dynamic updates through multi-threading techniques is provided. The results obtained by the analysis and evaluation of the proposed method, indicates the establishment of compatibility between the services, and finding the best possible substitute to reduce substitution time.
关键词：thesai; IJACSA; thesai.org; journal; IJACSA papers; component; indirect substitution; SLA; service composition; quality of service
