Research On Wireless GIS Based Agent Technology

GIS, as a comprehensive discipline of computer science, geography, surveying, cartography and other disciplines, the development is closely related to the development of other disciplines. In recent years, the more and more applications promote more demands of GIS, which promote the rapid development of GIS. The new technologies in the field of computer science, such as three-dimensional technology, wireless communication technology, image processing, object-oriented database technology and artificial intelligence technology has been directly used in GIS. In the 21st century, the rapid development of information technology, the integration of grid computing, virtual reality,3S and other new technologies has opened up more new research directions in the development and applications of GIS technology.The developments of Internet technology, information technology, wireless communication technology, space information technology and virtual reality technology make wireless, mobile GIS production became a necessity. The combination of Wireless communication technology, mobile positioning technology, and GIS technology, has come up with some new service and economic growth for the spatial information services. After several stages of development, the GIS technology based on mobile computing and wireless networks has been one of the most important parts of spatial information science. The emergence and development of it make up the defects which caused by the traditional cable network, meet a variety of demands from users under wireless environment, and also expand the applications of GIS. At the same time, the characteristics of the wireless network itself brings a new research field and direction for wireless network-based GIS.Compared to traditional wire network, wireless network has all the characteristics of cable network, and also it is more flexible and the cost is low. Wireless use radio waves as the transmission medium, which make it more convenient and mobile, easier for setup and maintenance. The biggest difference between wire network and wireless network is whether they support mobile computation. Wireless network is able to achieve the effect of an unlimited extension of broadband networks, which can compensate the disadvantages of cable network. The research objective on wireless GIS is to provide more applications and extensions for mobile and wireless, optimize the spatial information service quality, and provide a new application filed and processing methodology for geographical space science.In this paper, we analyzed the constitutes of wireless GIS, discussed wireless GIS technology and computing model, and summarized the problems the wireless GIS are faced with, for example, the low transmission rate under wireless network environment, the diversity of wireless terminals, the limited computing capability of wireless terminals, the unstable characteristics of wireless signal, and so on. In response to these issues, we introduced the Agent technology into wireless GIS. Concerning the characteristics of Agent technology, we proposed the new idea of wireless GIS based on Agent technology.Agent technology stems from the field of DAI in artificial intelligence. It is a computing entity and program which can achieve a series of goals which can sense the environment under certain conditions. It is the result of artificial intelligence, distributed technology, and network technology. Mobile Agent is a special Agent, and it can save network bandwidth, overcome network delay, interact remotely real-time, self-execute asynchronously, and compute offline. MAS system is the integration of many Agents. They could communicate and coordinate with each other and to resolve big complex issues. The emergence of Agent provides new solutions for large-scale, dynamic, complex, and distributed applications, and also provides new ideas and methods for the research and applications of wireless GIS.In response to some key problems such as low transmission rate, big transmission cost, the change of transmission quality, this thesis started from studying the adaptive theories of wireless network, and analyzed a series key problems to be resolved in wireless transmission. The dynamic characteristics of network resources make the transmission methodologies need appropriate match. This thesis used the general wireless transmission model and analyzed it under wireless environment to propose multiple Agent self adaptive transmission model (MATM). Through optimizing the transmission model, this thesis proposed the optimal strategy for self adaptive transmission, and the principles of the algorithm was analyzed in detail. Because of the diversity and complexity of spatial objects, we analyze the implementing process of scheduling, and test the feasibility of the Multi Agent adaptive transmission model. It was testified that this model can improve the transmission rate of spatial data and reduce the effects from wireless network through real datasets.At present, with the rapid development of network, the service for spatial data is getting more and more. The diversity, heterogeneity, and distribution characteristics of spatial data are challenging the traditional spatial information service. Based on the research on wireless spatial information service, this thesis proposed the idea of integration of MAS and GIS which coupling the ideas of SOA and Web services and the characteristics of Agent. Geographic information service coupling MAS technology under wireless network environment was the main research topic in this thesis. The main idea was to set up a wireless GIS integrated service platform coupling MAS system, utilize multiple Agent work together, coupl traditional GIS modules, organize the GIS service and data in the network dynamically, so as to realize the wireless GIS integrated service. Based on this, the thesis discussed the expression and modeling process of spatial information coupling GIS, studied the strategy of analysis, decomposition, distribution, and cooperation based on MAS, o researched the advantages of using MAS to complex wireless network tasks for the users, and also talked about the implement of coupling MAS for spatial information. It is essential to large-scale spatial analysis and computation.After the research on the theory of spatial information self adaptive transmission and MAS coupling GIS technology, the wireless GIS experimental system was built based on Agent technology, which was MAS coupling wireless spatial information service system. The theory of the system was to utilize MAS technology to coupl all the spatial information service and data which were distributed in three servers, in order to realize the wireless spatial information integrated service through the communication and cooperation among all the agents in the MAS. The effectiveness of the spatial data transmission based on Agent technology and the feasibility of GIS service coupling MAS was testified by experiments.