Research On Keyword Querying Over Fuzzy XML

With the rapid development of Internet and the increasingly large Web data,the Web data processing has become more and more important.In recent years,Extensible Markup Language XML(Extensible Markup Language)quickly appeared and has been widely used.As the Next-Generation Web Language,XML is independent of various software and hardware.It allows developers to define labels freely,and to separate the label and the content effectively.XML has been gradually evolving as the data interchange format for cross platform,and has become the actual standard for data exchange on Web.At present,XML technology plays an increasingly important role in the Internet,it is the foundation of information data management in the Web Era.The field of data management based on XML has attracted widespread attention in academic circles.The query theory and technology for XML data becomes an important research subject in the database area.In the real world,there always exists a plenty of imprecise and uncertain information,XML with the flexible feature can make good expression of fuzzy data which contains imprecise and uncertain information.The fuzzy data management based on XML becomes an important research issue in database research field,one important research content of fuzzy XML data management is the query technology of fuzzy XML.Existing related research for fuzzy XML data management mostly focus on the aspects of fuzzy XML data model,the structure query of fuzzy XML data,fuzzy XML reasoning and so on.Keyword query is an important form of XML query,but there are few research achievements on the keyword query technology for fuzzy XML data,and the many important theory and technical problems have not yet been involved.In view of this research status,the research work in this paper will focus on the keyword query technology for fuzzy XML data,and conduct in-depth study around the keyword query technology and optimizing query technology of fuzzy XML data.Different query methods for keyword querying on fuzzy XML data are proposed,the specific research contents include the following aspects:(1)Based on the traditional SLCA semantics of XML keyword query,the query semantics for keyword queries on fuzzy XML documents is proposed,a new encoding mode CDewey and a new scoring method for results are proposed,and a stack-based algorithm FIndex Loop is proposed,the algorithm can obtain the SLCA nodes with their scores of Top-K keyword querying on the fuzzy XML document,it can get the K SLCA results with the K highest scores of keyword queries on fuzzy XML documents effectively and efficiently.(2)In order to match partial query keyword(s)in fuzzy XML data and obtain the more relevant results of keyword queries,the object-oriented keyword query semantics and query method are proposed.The concepts of "object tree" and "minimum object tree" are introduced and the fuzzy XML document is processed with the object identification operation.For the query keywords inputted by users,the partial matching result object trees containing partial keywords and the minimum whole matching result object trees containing all keywords are found in the fuzzy XML document.A stack-based algorithm named Object-stack is proposed.This algorithm can obtain the root nodes of matching result object trees which contain partial keywords and the root nodes of matching result object trees which contain all keywords.And the K root nodes of matching result object trees with the K highest scores are obtained also.The K matching result object trees with the K highest scores are obtained.The Top-K matching results object trees with the highest scores can include partial matching result object trees and minimum whole matching result object trees.By introducing the object-oriented idea,the query results returned are more accurate and meaningful,as each query result contains a piece of complete object information and the query results matching partial keywords can be returned,which makes the query results more comprehensive.(3)Aiming at the data redundancy problem which exists in the subtree type results of keyword querying over the fuzzy XML data,an approximate keyword query method for fuzzy XML is proposed.The concepts of minimum connecting tree(MCT),distance minimum connecting tree(DMCT),group distance minimum connecting tree(GDMCT)are introduced,the query problem of all GDMCTs on the fuzzy XML document is proposed.Under the condition of given subtree size threshold and given possibility threshold,the method of getting the minimum connecting tree results which are rooted at the LCA nodes of the inputted keywords of keyword queries on the fuzzy XML document.A stack-based algorithm All fuzzy GDMCTs is proposed,it can obtain the all GDMCTs results of keyword queries which satisfy the condition of given subtree size threshold and possibility threshold,and the minimum connecting trees which are contained in the GDMCTs results are obtained.At last,the experiments show that the approximate keyword query method can obtain the relatively accurate query results under the condition of given subtree size threshold and given possibility threshold.