Research On Key Technologies Of Geographic Information Services Discovery And Compostion Based On Semantic

In order to reduce cost of society construction, the people expect that geographic information resources can be shared and value-added as more as possible. This requirement need forward higher requirements to geographical information system in networking, standardization, sharing and interoperability. As a self-contained, self-describing and modular application programme, Web Service can achieve remote discovery, assembly and integration by using service interface and message protocol after packaging resources and resources operations. Therefore, service can better meet the above social requirement. The improving of the science and technology, particularly continuous improvement of network technology and web technology, provide the necessary technical support for the geographic information system develop into geographic information services. Geographic information services published GIS data and functionality on the Web in the form of services. The serviced persons can use the network services directly in theirs application while they do not need to know the details of services. At last, geographic information can realize the sharing of geographic information, interoperability and value-added by this way. In this case, More and more geographic information resources exist on the Internet in the form of services.Facing the growing geographic information services in the network, how to discovery and assemble the suitable geographic information services efficiently and accurately for a given user requirement is one of bottlenecks of the development and application of geographic information services.This paper contemplates studying the key technologies of the geographic information services’discovery and combination in the semantic web environment.This study idea is following, first, study geographic information service discovery in the semantic model; then, study the combination and the implementation of geographic information services; final, mining knowledge in the results of the combined, and use the knowledge in the new discovery and composition of services. This research mainly involves the following aspects:(1) Semantic Web-based geographic information service discovery.This paper has three strategies for the discovery of geographic information services:service discovery based on Syntax similarity; Service Discovery Based on Semantic Model; Service Discovery Based on Oracle Spatial 11g semantic technology. Service discovery based on Syntax similarity mainly to estimate the matching degree of service based on the both service name and parameters. Service Discovery Based on Semantic Model mainly to estimate the matching degree of services based on semantic similarity of the ontology concept model. Service Discovery Based on Oracle Spatial 11g semantic technology mainly put Oracle Spatial 11g as the data management platform and full use of its efficient and mature management technology for semantic data to discover geo-information services.(2) Combination and implementation of Semantic Geographic Information Services. In this paper, it presents three possible combinations contrapose to the combination of geographic information services:user manual combination; semi-automatic combination; Automatic combinations. In order to be able to implement builded service chain effectively, this paper research and analysis the OWL-S API, extended and use OWL-S API library functions to achieve the implementation of the service chain.(3) Knowledge mining from combination results of geographic information services. First, this paper based on the concept lattice to dig out rules and relationship contained in services database, such as the level of the correlation between frequency of use of services and combination between services. Then, describe and reflect the rules and relationships use dynamic index table.Finally, dynamic index table is used for optimization of discovery and combination of services. When service was finding, index table build by knowledge mining, can give priority to that high frequency of use and high support degree of combine services to improve the efficiency of service discovery. In the final of the paper, it designs and develops a prototype system have functions of geographic information service discovery and composition on the basis of above research content.