Research And Application On Spatial Environment Service Composition Technology Based On Semantics

The space environment affects the normal operation and service life of the spacecraft,and severe space environmental events can lead to the breakdown of satellite systems,communication systems,navigation systems and power systems.The space environment forecast is a necessary work to understand the state of the space environment,and it is also the basis for space activities.With the continuous deepening of space science exploration and research,the number of space environment monitoring data and space environment forecasting models has increased rapidly,and the number of institutions using space environment forecasting services has gradually increased,but the degree of sharing of models and data among institutions is weak.The geographical distribution and heterogeneity of data and model resources have made the problems of sharing,flexibility,and scalability of centralized data storage and model integration systems increasingly serious.Models and data,such as spatial environment resources,are shared remotely.Interoperability and intelligent generation of forecast products have become urgent needs in the field of space environment forecasting.Web services can encapsulate resources and provide a unified call and message exchange interface for developers and researchers to use through the Internet.It has the advantages of reusability,loose coupling,cross-platform,and composition and orchestration.Encapsulating spatial environment resources as Web services is an effective way to realize remote sharing and interoperability of spatial environment resources in a distributed environment.With the development of Web services technology,some spatial environment data platforms have supported users to implement simple online processing and calculations.However,the business requirements of spatial environment forecasting are complex and diverse.A single spatial environment Web service often cannot meet the demand and requires multiple The space environment services are dynamically combined to form a service chain that can fulfill the user's space environment forecasting task requirements.Based on the research on web services and service composition related technologies,this paper proposes a method of spatial environment service composition based on semantics,realizing the automatic construction of a space environment service chain according to user needs,and taking the ionosphere TEC forecast as an example,the execution framework for service composition authenticating.The main research contents and results of the paper are as follows:(1)Research on web services and service composition standards and specifications of spatial environmental information.Based on the research of web service principles,architecture and related technologies,according to the characteristics of space environment data and model resources,the standard specification of space environment service encapsulation is proposed,and the implementation method of space environment service is studied..(2)Research and Implementation of Automatic Composition Method of Spatial Environment Information Service Based on Semantics.On the basis of fully researching and analyzing the relevant technologies of service composition,a semantic environment-based service composition method is proposed.Combined with the language characteristics of the space environment field,a semantic similarity calculation method suitable for the language of the space environment field is realized.The method of calculating the semantic similarity between the descriptions of service interface is used to judge the composability between the space environment services.According to the service interface matching algorithm based on semantic similarity,it realizes the automatic construction of the spatial environment information generation service chain according to the user's specific task requirements.(3)Design and implementation of a prototype system for space environment service composition.With the service registration center,service composer,and service chain execution engine as the main modules,an intelligent space environment service composition prototype system is realized.Taking the user demand predicted by the ionosphere TEC as an example,the service combination and execution system are verified.