一種面向集合的空間關鍵詞查詢方法研究
發(fā)布時間:2018-11-26 09:25
【摘要】:如今,定位技術的快速發(fā)展使得基于位置的服務得到了廣大移動用戶的青睞。隨之而來的,各種擁有定位技術的移動設備不斷推陳出新,各種基于位置信息和文本信息的查詢被提出。為了滿足這樣的查詢需求,學術界對于不同條件的查詢需求分別提出了各種高效的空間關鍵詞查詢算法。空間關鍵詞查詢按類別分為,單一對象匹配的空間關鍵詞查詢,面向集合的空間關鍵詞查詢,面向集合和方向的空間關鍵詞查詢。不同類型的查詢,在不同的查詢條件或不同的查詢環(huán)境中,也有各種不同的查詢算法。道路網(wǎng)是人們生活空間的抽象,研究道路網(wǎng)上的空間關鍵詞查詢更有實際意義和使用價值。到目前為止,人們還沒有研究過道路網(wǎng)上方向和集合同時被考慮的空間關鍵詞查詢。在前人的研究基礎上,本文提出了一種基于道路網(wǎng)的面向集合和方向的空間關鍵詞查詢方法。首先,把整個道路網(wǎng)分割成幾個相連的局域網(wǎng),以局域網(wǎng)層次的結構建立空間索引,為每個局域網(wǎng)建立倒排索引,目的是每次查詢時,可以快速的跳過不包含查詢關鍵詞的區(qū)域直接進入下一個包含查詢關鍵詞的局域網(wǎng)進行查詢。然后,找到在指定查詢方向上并且在指定查詢范圍內(nèi)的局域網(wǎng)。最后,在獲得可查詢的局域網(wǎng)內(nèi),查詢出滿足查詢文本信息和空間位置信息及查詢范圍約束的一條路線,這條路線滿足:1)路線上的空間對象文本信息能夠共同滿足查詢的文本信息;2)此路線是最優(yōu)的路線,即查詢用戶從查詢位置出發(fā),走此路線能把所要做的事情完成,并且是代價(可以是行走的路程或者行走的時間或者所消耗的費用等)最小。本文針對道路網(wǎng)上面向集合且受查詢方向約束的空間關鍵詞查詢,提出了面向無主關鍵詞的查詢和主關鍵詞優(yōu)先的查詢。無主關鍵詞的查詢即從查詢點出發(fā)按照道路網(wǎng)在可查詢范圍內(nèi)擴展查詢。主關鍵詞優(yōu)先的查詢,首先在可查詢范圍內(nèi)以一種迭代替換的方式進行擴展查詢直到查詢到主關鍵詞對象,若還有關鍵詞沒有被已查詢到的空間對象所覆蓋,則以面向無主關鍵詞的查詢方式繼續(xù)進行擴展查詢。本文對這兩種查詢分別給出了查詢算法。最后,分別對以上兩種查詢進行了實驗,證明了所提算法的有效性。
[Abstract]:Nowadays, with the rapid development of location technology, location-based services are favored by mobile users. As a result, various mobile devices with location technology are constantly emerging, and various queries based on location information and text information are proposed. In order to meet this query demand, the academic community proposed a variety of efficient spatial keyword query algorithms for different query requirements. Spatial keyword query is divided into categories, single object matching spatial keyword query, set and direction oriented spatial keyword query. There are different query algorithms in different query conditions and different query environments. Road network is the abstraction of people's living space. Up to now, people have not studied the spatial keyword query that the direction and set of road network are considered simultaneously. On the basis of previous researches, this paper proposes a method of spatial keyword query based on road network oriented to set and direction. First of all, divide the whole road network into several connected local area networks, build spatial index with the structure of local area network, build inverted index for each local area network, aim at every query, Can quickly skip the region without query keywords directly into the next local area network containing query keywords for query. Then, find the local area network in the specified query direction and within the specified query scope. Finally, in the local area network that can be queried, a route satisfying the query text information, spatial location information and query range constraints is found. This route satisfies: 1) the spatial object text information on the route can satisfy the query text information together; 2) this route is the best route, that is to say, the query user starts from the query position, and takes this route to complete what needs to be done, and it is the least cost (it can be the distance or time spent or the expense consumed). Aiming at the spatial keyword query which is set oriented and constrained by the query direction on the road network, this paper proposes a query oriented to the main keyword and a query with the primary keyword first. The query without main key words starts from the query point and expands the query according to the road network within the range of query. In the main keyword first query, the query is extended by an iterative replacement method within the query scope until the main keyword object is queried, if the keyword is not overwritten by the queried spatial object. Then the extended query is continued in a way that is oriented to the key words. In this paper, the two query algorithms are given respectively. Finally, experiments on the above two kinds of queries are carried out to prove the effectiveness of the proposed algorithm.
【學位授予單位】:哈爾濱工程大學
【學位級別】:碩士
【學位授予年份】:2016
【分類號】:TP301.6
本文編號:2358141
[Abstract]:Nowadays, with the rapid development of location technology, location-based services are favored by mobile users. As a result, various mobile devices with location technology are constantly emerging, and various queries based on location information and text information are proposed. In order to meet this query demand, the academic community proposed a variety of efficient spatial keyword query algorithms for different query requirements. Spatial keyword query is divided into categories, single object matching spatial keyword query, set and direction oriented spatial keyword query. There are different query algorithms in different query conditions and different query environments. Road network is the abstraction of people's living space. Up to now, people have not studied the spatial keyword query that the direction and set of road network are considered simultaneously. On the basis of previous researches, this paper proposes a method of spatial keyword query based on road network oriented to set and direction. First of all, divide the whole road network into several connected local area networks, build spatial index with the structure of local area network, build inverted index for each local area network, aim at every query, Can quickly skip the region without query keywords directly into the next local area network containing query keywords for query. Then, find the local area network in the specified query direction and within the specified query scope. Finally, in the local area network that can be queried, a route satisfying the query text information, spatial location information and query range constraints is found. This route satisfies: 1) the spatial object text information on the route can satisfy the query text information together; 2) this route is the best route, that is to say, the query user starts from the query position, and takes this route to complete what needs to be done, and it is the least cost (it can be the distance or time spent or the expense consumed). Aiming at the spatial keyword query which is set oriented and constrained by the query direction on the road network, this paper proposes a query oriented to the main keyword and a query with the primary keyword first. The query without main key words starts from the query point and expands the query according to the road network within the range of query. In the main keyword first query, the query is extended by an iterative replacement method within the query scope until the main keyword object is queried, if the keyword is not overwritten by the queried spatial object. Then the extended query is continued in a way that is oriented to the key words. In this paper, the two query algorithms are given respectively. Finally, experiments on the above two kinds of queries are carried out to prove the effectiveness of the proposed algorithm.
【學位授予單位】:哈爾濱工程大學
【學位級別】:碩士
【學位授予年份】:2016
【分類號】:TP301.6
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