| Location Based Service (LBS) is based on wireless Internet technology andmobile communication technology, combined with the mobile positioning technologyto provide the current geographical position and the surrounding business informationfor mobile wireless terminal. With the development and prevalence of GPS mobilephone and intelligent mobile phone, people’s way of life has changed greatly In orderto meet people’s urgent needs of LBS, Location Based Service has become a hotindustry in current society. For the application of LBS, it’s required to provide thecomprehensive spatial information service for users, while the supportedgeographical spatial data is huge, with much thematic data, and real-time update isalso demanded, therefore, the current hotspots of research are how to share, integrate,and manage the distributed positioning resources and spatial information resources,how to share and integrate the distributed location application service, and how toconstruct the distributed LBS service platform in LBS application.Web service integrates the existing application software in a distributed andloose coupling way to realize thesharing and reuse of the software and hardware anddata on Internet. Semantic Web service combines the advantages of the semantic Weband Web serviceIn the service description, it adds the semantic information based onontology, which is a kind of intelligent Web service. On Internet, Web service isgrowing rapidly, and all kinds of services are huge, even the same type of service inthe service registration center may also be thousands upon thousands,moreover, thedistributed multiple service registration centers may operate simultaneously, forminga P2P network. To quickly find the most accurateand complete service is theultimate goal of semantic Web service discovery research. In order to improve the service’s precision rate and recall rate, semantic Web services discovery combinessemantic information with Web service discovery.The existing LBS service integration platform does not achieve a completeservice system, which should make a nice combination of the location service and thespatial data service and Web service together. It is not good enough for expandingthe service semantic description supported LBS. The construction of LBS domainontology, is still at the primary stage. The existing LBS service matching algorithmsare mainly based on the centralization, and the research of large-scale and thedistributed service discovery algorithms is not enough.In view of the above questions, the following work has been done in this paper:1. Construct the LBS service platform structure based on semantic WebWith reference to the issued standard and criterion by the geography branch ofInternational Organization for Standardization (ISO/TC211) and Opern GISConsortium (OGC), a distributed LBS service platform structure based on semanticWeb is proposed in the paper, and the detailed introduction is also done for thestructure of semantic registration center in service layer, moreover, a distributed LBSintegrated service topology structure, and the deployment of intelligent agents basedon P2P network, so that the distributed positioning application service, geographicalspatial data service and Web service are all integrated together, which can realize thesharing and mutual operation of all kinds of spatial resources and services in LBSapplication area, forming a complete service system.2. Construct the ontology structure ofLBS and expand LBS services semanticdescriptionAfter the introduction of the ontology definition, classification and basicmodeling original language, LBS ontology architecture is constructed from ontologyclassification and distributed hybrid ontology mode in two dimensions. LBS ontologyis modeled according to the modeling rules The core parts are the modeling of LBSdomain ontology and application ontology, the expanding of QoS semantic description, and the construction of LBS QoS ontology which is the semantic supportof LBS service discovery.3. Define a semantic service registration center structure and construct a servicediscovery framework based on semantic.The semantic Web service registration center structure is designed. In thedistributed LBS service architecture based on semantic Web service, the mostimportant part is the design of the UDDI registration center. In the design, on the baseof the traditional UDDI management modules, semantic management module isaddedto manage ontology knowledge base and semantic routing and tag semantic, aswell as OWL_S language is used to descripte Web services and the semanticextension of QoS is done; then the registration center service matching is designed inthe service discovery modules, and the three stages service matching model based onsemantic description is proposed in the paper,which consist of the type of servicematching, the function of service matching and the quality of service matching;inaddition, according to the characteristics of distribution, the P2P distributed servicediscovery module is also designed; finally the Agent technology isintrouced, makingintegrated platform has good intelligence.4. An efficient and comprehensive semantic service matching algorithm isdesigned on basis of multi-stage service matching modelAn efficient and comprehensive semantic service matching algorithm isdesignedaccording to the semantic annotation of service description and semanticthree-stage service matching model. The multi-dictionary similarity algorithm isspecific introuduced, which improves the lexical semantic tagging algorithmthroughcombining multiple dictionaries to increase the realiability of dictionary similaritycalculation method. A fine grained comprehensive semantic similarity algorithm isalso proposed which combines with the depth, density and concept attributesimilarityof the ontoloty concept tree to educe the comprehensive semantic similarity betweentwo concepts. In addition, QoS matching algorithm is put forward. Through the combined application of the three algorithms, the service matching precision andrecall ratio are improved.5. A distributed service discovery algorithm based on ant colony algorithm isput forwordA novel distributed service discovery algorithm based on ant colony algorithm isproposed, in which the semantic routing is set in P2P distributed network and theprobability selection mechanism based on ant colony algorithm is introduced. In theprocess of the distributed service discovery, the ant colony pheromone matrix and theconcurrent quantity of messageof each node are set. Thus, when choosing the nexthop node, the message would make the probability choice according to thedistribution of the pheromone; moreover, the optimal parameter can be determinedthrough the parameter analysis of the concurrent quantity of the message Futhermore,the results of the simulation experiment show that this algorithm could improve therecall rate and efficiency of the distributed service discovery compared with thetraditional algorithm.6. For vehicle network service, service search algorithm on basis of semanticrouting is proposedA semantic routing protocol based on the vehicle network is proposedthrough theuse of domain LBS ontology model. Then the availability of these workwascomfirmed by experiment. The innovation of this algorithm contains theconsideration of the characteristics of the vehicle network dynamic P2P, and theapplication of the ontology semantic routing discovery algorithm to explore itsfeasibility and availability. The experiment shows that it could achieve good recallrate without too much network load.The LBS service platform architecture based on the semantic Web is constructedin the paper, and the LBS semantic description is also expanded, besides, the semanticservice discovery algorithm is also improved which has the certain theory significanceand application value. |
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