基於行動端點位置之動態查詢分配

Dynamic Query Assignment based on the Location of Mobile Host

游柏瑞(Bo-Rei Yu)

指導教授 ： 張明峰

國立交通大學/資訊學院/網路工程研究所/碩士(2009年)

https://doi.org/10.6842/NCTU.2009.00894

摘要

隨著無線網路與行動通信的快速發展，與手持裝置與行動裝置的廣泛使用，以及全球衛星定位系統的普及，位置服務能基於使用者的位置提供在地化的資訊，使得現代人可以享受的智慧的生活型態。位置查詢的型態也分為很多種類，連續的位置查詢會持續一段時間，期間的結果也須保持正確，被查詢的物體也可能會移動。範圍監測查詢是一個連續的查詢，如果指定區域內的狀態有改變，須回報伺服器來更新結果。目前位置服務大多是採用伺服器與用戶端的架構，當使用者數目或是查詢要求增加，系統的負擔與可調適性將會是個挑戰。分散式的計算能讓行動端點分擔伺服器的計算。在本研究中，主要的範圍分為兩個，一個是查詢結果的更新問題，另一個是分配範圍監測查詢給行動端點之問題。本系統之設計為分配一個矩形區域給行動端點，包含數個範圍監測查詢，如果行動端點其在此區域內且不影響到範圍監測查詢，則不須向伺服器回報其位置更新以及查詢結果之改變。本系統能基於行動端點之位置和能力，分配範圍監測查詢，使得查詢結果更新之次數減少，整個系統的負擔將會減輕，可調適性增加，系統便可提供更大容量與更多樣的服務。

關鍵字

位置服務 ； 範圍查詢 ； 範圍監測查詢 ； 查詢分配 ； 查詢更新 ； 位置更新

並列摘要

LBS services are capable of providing information based on the user’s location. There are many varieties of LBS Query. Continuously queries continuously update its result until the users terminate the query requests. Range monitoring queries are typical examples of continuous queries. If there is any change in the region under monitored, LBS must update the query result immediately. LBSs are usually implemented in client-server architecture. When the user population is huge and many requests are sent to the server. The scalability of the LBS server becomes a problem. Distributed client-server architecture enable clients to share their computing ability with the server. One possible distributed solution is that the LBS server assigned queries near each mobile client so that the clients can check if the queries match. There are two problems in this approach. One problem is query result update. The other problem is query assignment. In our design, we compute a rectangle area for every mobile host. The mobile hosts aware the range monitoring queries in the region. If the mobile host is inside the region and does not affect any query in the system, it does not need to report to the server. Our system dynamically assigns range monitoring queries to the mobile hosts based on their capability. The query update messages and the server load in the system are reduced. The system scalability is also increased.

並列關鍵字

Location Based Service ； Range Query ； Range Monitoring Query ； Query Assignment ； Query Update ； Location Update

參考文獻

2. D'Roza, T. and G. Bilchev, An Overview of Location-Based Services. BT

1. Kupper, A., Location-based Services: Fundamentals and Operation. 2005:

John Wiley & Sons.

4. Zhang, J., et al., Location-based spatial queries, in Proceedings of the 2003

San Diego, California. p. 443-454.