The service discovery methods based on structure matching has high computational cost and can not distinguish the Web services with similar semantics but in different structure definitions, due to the flexibility of XML Schema. To solve this problem, a so-called fine-grained data semantics method is proposed, which can be obtained by a transformation algorithm that decomposes parameters at message level into a set of fine-grained data parameters. The fine-grained data semantics is transparent

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... the specific data structure of message-level parameters, therefore, it can help to match successfully similar Web services with different data structures of parameters. Experiments show that the proposed method can improve the effectiveness of service discovery. In recent years, along with the improvement of the related standards of Web service and the gradually mature software platform which support the Web service development, the number of Web services on the Internet is continually growing. Web service discovery is an important part of the Web service structure. Its task is to find the service which can meet customers' demand t from the huge number of server on the Internet, and its core is a service matching algorithm of good performance [1]. The current Web services matching algorithm is mainly divided into grammatical level and semantic level. The core of semantic Web service technology is to use the ontology to give an ontological description of Web service, thus making the semantics much clearer. The semantic Web services technology discovery has a higher accuracy, but the time complexity of ontology reasoning is too high; and, to accurately mark a large number of Web services is a heavy task[2,3]. At present the web services on the internet are growing day by day and the semantic web service technology is still not mature. Therefore, how to further improve the efficiency of the web service discovery becomes an urgent problem to be settled. This paper proposes a decomposition algorithm, which will decomposes various types of data structures that describe WSDL operation information elements into a set of elements with the basic data type, and then turns the SAWSDL service matching based on messages into more fine-grained semantic matching data. SEMANTIC ANNOTATION FOR WSDL SAWSDL (Semantic Annotation for WSDL) is the W3C recommended standard improved on the basis of WSDL. Its original version is WSDL-S language proposed by the team MeteorS in LSDIS laboratory, Georgia University[4,6]. SAWSDL is to extend WSDL elements by using ontology annotation methods to represent the semantic information of Web services. By using external semantic model, service providers can choose their domain ontology to annotate service interface parameters. The SAWSDL documents have both structure characteristics of WSDL documents and semantic description characteristics of Web services, which is shown in detail as follows: 1) structuralized characteristics of messages In SAWSDL services description, the type of operation messages is by default regarded as the data type of XMLSchema definition. The message type can be the basic type of XML Schema, and also can be the simple type and complex type defined in XML Schema, while the diversity of message types makes the message matches become more complex.