| Along with many coast conturies hardly developing marine resources,however,marine calamities such as red tides emerge more frequently,increaing the size and getting longer and longer duration,as a result of growing marine pollution activities, which caused serious impact on our marine ecosystem and huge loss on economics directly or indirectly.Thus it has pressing needs to develop the marine environment online monitoring and marine disaster intelligent forecasting system and devise marine monitoring and calamities publication system and research on its real-time ability and reliability, which will help maintain the rights and intrests of marine,explore marine resource,make marine disasters forecast,protect marine environment and seek new development space.Originates from research funds on marine monitoring of ShanDong Province,this thesis mainly concerns on the marine environment monitoring information publication subsystem based on embedded WebGIS of the whole project. The research focus on techniques and strategies used to enhance and guarantee system real-time ability,used B/S network architecture,based on embedded environment of mornitoring station site,and supply real-time marine monitoring and calamities predicting information publication.The thesis first introduced the background topics and reseach significance of subject,and current study situation on marine monitoring system, and introduced its content construction,then gave the description of the whole architecture of marine environment online monitoring system and the function of its four inner subsystems,included data monitoring,data management,model analysis and data product.The following chapters presented architecture design and key techniques of the marine environment monitoring information publication subsystem.The whole system employs a three-tiered architecture based on browser and server, responsible for dealing with the request for information of user's browser,sending requests for information to the data center,integrating the data received from the data center including vector space data stored in the GIS database and monitoring information stored in the history database and products database,and monitoring data received from local embeded database,and provides the appropriate GIS services to satisfy the requirements for information visualization of customer's browser.From the location of space,the embedded WebGIS information publication subsystem located on monitoring station is the center of entire monitoring system,is the direct platform of information visualization publication to users.From the functional structure,its play a "middleware" between users and data center.Thus the real-time performance of marine environment monitoring information embeded WebGIS publication subsystem plays the key role on the whole monitoring system.The thesis mainly considered how to promote real-time ability on data structure,encapsulation and visualization publication,which include key techniques like data structure for embeded GIS, compression of data collection based on XML,encapsulation of monitoring data based on GML and visualization publication based on SVG,etc.The thesis finally gives a progressive transmission strategy of vector spatial data for embeded network and a real-time clustering algorithms for red tide monitoring data.One is based on thorough discussion of models for progressive transmission of vector spatial data,adopted an variant multi-way search tree named level search tree,cater for progressive transmission of vector spatial data in embeded WebGIS information publication system located on monitoring station,which enhances its real-time ability and saves much bandwidth.Another one aims to the different impact of red tide monitoring elements to occurrence,and even some information repeat each other.The proposed real-time clustering algorithms based on the attribute distance weighted enhance its real-time performance and accuracy in its application on the clustering mining task of data center. |
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