Research And Implementation Of Task-Driven Land Cover Information Dynamic Service Combination Mechanism

With the rapid development of Earth observation and remote sensing information processing technology,global land cover data is increasing year by year,and the construction of service-oriented global surface coverage information sharing platform has become a research hotspot of many organizations.However,for the dynamic update of land cover information data,the manual processing method based on offline desktop end is heavy.With the gradual deepening of Web Service technology applications,some data sharing platforms have allowed users to implement simple online processing operations in a distributed environment.However,in the face of increasingly complex land cover data and algorithm models,a single online processing service can no longer meet the real-time,personalized needs of users.How to form a service chain oriented to user needs through a specific combination mechanism is a major research issue in the current online calculation of surface coverage information.Based on the research on the characteristics of land cover information service,this paper constructs a land cover information service description framework based on the logical relationship between data service and processing service itself and the two,and builds on WS-BPEL.A task-driven dynamic service composition mechanism that builds a service portfolio that meets user needs in real time.The specific research work of the thesis is as follows:(1)The traditional dynamic service composition method and semantic Web related theory technology are discussed.By analyzing the Web service description framework and the dynamic service composition method,combined with the characteristics of the surface coverage information service and user requirements,the key issues of surface coverage information service description are proposed.The service resources in the surface coverage information environment are analyzed,and combined with OWL-S,the surface coverage information service description framework(DP-OWLS)is proposed and constructed by Protégé ontology modeling software.(2)Based on the proposed DP-OWLS framework,the mapping rules of WSDL and WS-BPEL are established by applying WS-BPEL technology,and the design principle of service composition process is formulated.A task-driven dynamic service composition mechanism is proposed.By obtaining user requirements,the demand atomic service and its logical relationship are inferred from DP-OWLS,and the service composition scheme is dynamically constructed.(3)Based on the above research on dynamic service composition mechanism,with the development of Django framework,Openlayers API and other related technologies,the land cover information service online computing prototype system is designed and developed,and integrated into the current project research results global land cover information sharing platform.Through the application case,the stability and timeliness of the method are verified,and the system can meet the business requirements of online computing in a distributed environment.