近年來GPS (Global Positioning Systems) 已經配備且支援在大多數的行動裝置中，而人們也越來越依賴適地性服務 (LBS，Location-Based Services)，進而產生大量的地理文本物件 (Spatial Textual Data)，因此需要空間關鍵字索引的技術來管理這些地理文本物件，以利有效率地存取。考慮到查詢範圍的數量往往比移動物件來的少，而其移動的頻率也比移動物件來的低許多，又因現今移動物件普遍具有不錯的計算能力，因此本論文採用不規則擴張方法搭配有效率的關鍵字過濾來處理空間關鍵字的搜索。給定移動物件一個精確的安全監控範圍，當移動物件在此範圍內移動時便不須頻繁的向中心伺服器回報其最新位置，以此來降低移動物件與中心伺服器的通訊成本。而關鍵字的過濾方法能有效且精確的回報查詢發起者感興趣的查詢結果，以此來提升查詢的效率。實驗結果證明，本論文之研究方法在監控範圍的部分優於對照組，在通訊成本與計算成本上也都明顯地比對照組降低許多。 Recently, most mobile devices have been equipped with GPS (Global Positioning Systems). People are more and more relying on location-based services (LBS), resulting in generating a large volume of spatial textual data. Hence, the efficient spatial-keyword-indexing technology is necessary to manage these spatial textual data to provide efficient access. The number of spatial keywords searches is less than that of mobile objects, and the mobility of the searches is lower than that of the mobile objects. Nowadays, mobile objects generally have the good computational ability. Therefore, we propose an irregular expansion approach with effective spatial keyword filtering to deal with monitoring spatial keyword searches. Given each mobile object an accurate monitoring region, when moving within this region, the mobile object does not need to frequently report its latest position to the central server. In this way, the communication cost between them can be reduced. The spatial keyword filtering approach can effectively improve the accuracy of the search, so that the search issuers can obtain search results of interest. Experimental results show that the proposed approach is superior to the competitive approach on the size of the monitoring region. The communication and computing costs in the proposed approach are also significantly lower than those in the competitive approach.
