N.-T. Nguyen et al. (Eds.): Adv. in Multimed. and Netw. Inf. Syst. Technol., AISC 80, pp. 131–141. springerlink.com © Springer-Verlag Berlin Heidelberg 2010 Chapter 13 Service Discovery Approach Based on Rough Sets for SOA Systems Krzysztof Brzostowski, Jakub M. Tomczak, Witold Rekuć, and Janusz Sobecki Abstract. In the chapter an approach to solve the problem of service matchmak- ing and discovery is discussed. By a service we mean a independent component which has specified inputs and outputs and some functional and non-functional features. In our approach to describe services ontologies are used. It helps us to include some semantics to the services. Process of service discovery is started when user’s request is translated into SLA contract. The problem of matchmak- ing and discovery can be defined as a problem of finding service which fulfil user’s requirements as much as possible. In this work we present a system of service discovery and then our contribution to this domain – rough set-based ap- proach to solve considered problem. Some simple example which illustrates pro- posed approach is shown. 13.1 Introduction The problem of services discovery is the crucial concern in system which based on service such as Service Oriented Architecture (SOA) [2, 5]. It is very important to ensure access to the tools which help users to find desired service. Service Ori- ented Architecture systems offer tools to solve this problem. In SOA systems some mechanisms and methods which help to meet expectation both service providers and service users are implemented. Generally we can denote these operations as description, publication, discovery and selection. Crucial part of SOA systems, which helps implementing mentioned operation, is ontology. Appli- cation of ontologies enables to convey the meaning of the formal terminologies to describe some real-world concepts [5]. In the service representation ontologies are Krzysztof Brzostowski, Jakub M. Tomczak, Witold Rekuć, and Janusz Sobecki Institute of Informatics, Wroclaw University of Technology, Poland e-mail: {Krzysztof.Brzostowski,Jakub.Tomczak}@pwr.wroc.pl {Witold.Rekuc,Janusz.Sobecki}@pwr.wroc.pl