Abstract-The perfect composition of atomic services to provide users with services through applying qualitative parameters is very important. As expected, web services with similar features lead to competition among the service providers. The key challenge to find an appropriate web service for composition occurs when multiple aspects of quality (such as response time, cost, etc.) are considered in the optimal composition of services. Skyline service provides the best service with consideration of qualitative parameters by using superior analysis. In this study, Skyline algorithm is used to find a set of best possible services compositions while taking into account qualitative parameters. The parallelism technique in this study, had significant impact on reducing response time and increasing the speed of service composition as well as reduction in composition calculations. The results of the analysis and evaluation of the proposed method shows optimum runtime and the best composition.

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Abstract:The combination of web services is the result of complex and increasing needs of the users and disability of single web services in resolving the user's needs. One of the important challenges in the field of web 2.0 is the combination of web services based on their qualitative features. Since it is probable that there would be several different combinations of services for achieving a specific goal, choosing the service is based on some qualitative features like combining, availability, acceptability, service cost and security. One of the important issues is the quantitative survey of combining rate of the two services shared on the combination so that they have the ability to combine with each other, correctly. In order to measure the combining ability of services, in the first stage, the more number of effective factors on combining features of services are surveyed in comparison with the present methods. In the second stage, metric is introduced for the effective factors, and in the third stage, an appropriate weight for each factor is found and finally, based on their relationships with each other, a more accurate rate of combining is obtained.