F. Eliassen and A. Montresor (Eds.): DAIS 2006, LNCS 4025, pp. 113 – 127, 2006. © IFIP International Federation for Information Processing 2006 Discovering Semantic Web Services with Process Specifications Piya Suwannopas and Twittie Senivongse Department of Computer Engineering, Chulalongkorn University Phyathai Road, Pathumwan, Bangkok 10330 Thailand piya.su@student.chula.ac.th, twittie.s@chula.ac.th Abstract. Service discovery is one of the crucial issues for service-oriented ar- chitectural model. Recently the trend is towards semantic discovery by which semantic descriptions are the basis for service matchmaking instead of simple search based on service attributes. OWL-S is a widely adopted semantic speci- fication for Web Services which comprises three profiles. Among those, proc- ess model is the profile that describes dynamic behaviour of Web Services in terms of functional aspects and process flows, and is generally aimed for ser- vice enactment, composition, and monitoring. This paper presents a new ap- proach to use OWL-S process model for service discovery purpose. A Web Service can have its internal process described as an OWL-S process model specification, and a service consumer can query for a Web Service with a par- ticular process detail. Matchmaking will be based on flexible ontological matching and evaluation of constraints on the functional behaviour and process flow of the Web Service. The architecture for process-based discovery is also presented. 1 Introduction Service discovery is an important part of service-oriented computing in which ser- vices, as building blocks for building applications, are provided and distributed in large-scale open environment [1]. Provided services will publish generalised descrip- tions of their capability to a matchmaker whereas service consumers consult the matchmaker to identify potential services that most closely satisfy their needs. The effectiveness of service discovery relies on the richness of service metadata and the matchmaking mechanism that utilises the expressiveness of the metadata. Current Web Services Standards realise this concept and provide UDDI [2] as a standard reg- istry that performs matchmaking based on matching of syntactic service attribute values. From our previous study [3], a service description model has been defined as a re- sult of an empirical survey about service advertisements on the Internet (Fig. 1). The model shows that service advertisements should reflect different aspects of service capabilities; some are simple characteristics and may be in the form of simple attrib- utes whereas some are more complex capabilities and require some specification languages to express them. (Those highlighted in Fig. 1 have no correspondences in