Research And Implementation Of Remote Sensing Metadata Query Technology Based On Fuzzy XML

Remote sensing metadata is data used to describe the content of remote sensing image data,and it contains basic information of remote sensing images.Today,the importance of remote sensing application is becoming increasingly prominent.As an important medium for remote sensing data integration and sharing,remote sensing metadata research is also of great significance.The acquisition process of remote sensing image data is affected by multiple factors such as hardware or software,which will produce certain uncertainty,and the corresponding metadata will also produce uncertainty.If this uncertainty can not be correctly described,the research results based on this will also produce large deviations.The current remote sensing metadata describes accurate remote sensing information.There are still some defects in the storage and expression of uncertain information.There is no clear distinction between general information and uncertain information.Therefore,for the storage and query of uncertain information in remote sensing metadata,In this paper,the theory of fuzzy sets and fuzzy XML are introduced into remote sensing metadata,and a remote sensing metadata model containing uncertain information is constructed.The uncertain information is represented by fuzzy constructors and membership degree.Using this model,the uncertain information can be correctly expressed.In order to query this remote sensing metadata for related information,this paper studies the keyword query algorithm and twig query algorithm of fuzzy XML.The main work is as follows.1.Aiming at the problem that the existing fuzzy XML keyword query algorithm FIndex Loop needs to iterate repeatedly when facing multiple keyword queries,which leads to low query efficiency,an efficient fuzzy XML keyword query algorithm LIndex Loop is proposed.The algorithm uses pruning method and node matching structure concept,avoids useless intermediate result calculation,and improves the efficiency of keyword query in fuzzy XML.2.Aiming at the problem of low query efficiency caused by TwigFX,an existing fuzzy XML twig query algorithm,which repeatedly calls functions to find extended solutions,this paper improves the twig query algorithm of fuzzy XML,and proposes BTwigFX algorithm.The top-down matching method of twig query is changed to bottom-up matching,and the root node is traced upward from leaf node to judge.It avoids useless recursive operations,reduces the number of recursions,and verifies the efficiency of the algorithm through comparative experiments.3.Finally,the uncertain remote sensing metadata query prototype system is realized.The prototype system combines the LIndex Loop algorithm with the BTwigFX algorithm to fully considering the requirements of the actual management application of remote sensing data,and realizes keyword query and twig query for uncertain remote sensing metadata.The query can obtain the XML subtree containing the query information and the corresponding possibility value,and verify the validity of the algorithm.