Time-Aware Spatial Keyword Cover Query And Collective Query Research

With the rapid development of geographic positioning technology,spatial keyword queries have attracted wide attention from spatial database research institutions and industry.The spatial keyword query utilizes the location information and textual information of the object to find a single or multiple objects that best match the parameters specified in the query.As people's needs increase,more and more users are paying attention to the valid time information of query objects.Therefore,in order to meet the needs of users,in this paper,we study the spatial keyword cover query and collective query further.Firstly,since the existing spatial keyword cover query only considers the relevance of the text and the position,and ignores the time information of the geospatial objects,a time-aware spatial keyword cover query(TSKCQ)is proposed,which takes into account the textual relevance,positional relevance,and time information of the objects.In this query,a new evaluation function is proposed,which is used to evaluate the user's satisfaction in time and space under the premise of satisfying text constraint proposed by the user.A TR-tree for indexing object temporal and spatial information of objects is designed,and an exact algorithm for the query is implemented by an effective pruning strategy,and the object set with the best evaluation function value is returned.Secondly,time-aware collective spatial keyword query(TCoSKQ)is proposed.TCoSKQ considers the location relevance,text relevance and time correlation of objects and query points.We define two new evaluation function to meet the different needs of users,and adopt the TR-tree index structure.An algorithm that can solve TCoSKQ is designed for each of the two evaluation functions.Based on the two algorithms,effective pruning strategies are proposed to improve query efficiency.Finally,the experimental comparison analysis is carried out with different data sets to verify the efficiency of the proposed algorithm.