在耐延遲網路上，離線的使用者，可以透過節點的相遇，以點對點之特定訊息繞送方法，將資訊傳遞至目的地。如此解決了使用者暫時無法上網時欲傳遞資訊之困難。因此，在本研究中，當使用者在某一地區，欲查詢該地區相關之資訊，但又一時無法連上網際網路時，則可透過耐延遲網路之特性，尋求其它同樣使用本服務之使用者幫忙以達到查詢之目的。
本論文提出一適地性服務之資料搜尋方法，以三層式區域概念，及混合式節點型態，並透過資料訊息複製、查詢訊息複製、資料回覆及資料同步等四項策略來達成使用者查詢之目的。特別在訊息傳遞方面，提出一訊息佇列選擇演算法，賦予優先權概念於每一訊息中，使得較為重要之訊息得以優先傳送，藉此提高查詢之成功率及減少查詢之延遲時間。最後，我們將本論文方法與其它查詢方法比較評估效能，其模擬結果顯示我們提出的方法有較優的查詢效率與延遲。 / In Delay Tolerant Networks (DTNs), the offline users can, through the encountering nodes, use the specific peer-to-peer message routing approach to deliver messages to the destination. Thus, it solves the problem that users have the demands to deliver messages while they are temporarily not able to connect to Internet. Therefore, by the characteristics of DTNs, people who are not online can still query some location based information, with the help of users using the same service in the nearby area.
In this thesis, we proposed a Location-based content search approach. Based on the concept of three-tier area and hybrid node types, we presented four strategies to solve the query problem. They are Data Replication, Query Replication, Data Reply and Data synchronization strategies. Especially in message transferring, we proposed a Message Queue Selection algorithm. We set the priority concept to every message such that the most important one could be sent first. In this way, it can increase the query success ratio and reduce the query delay time. Finally, we evaluated our approach, and compared with other routing schemes. The simulation results showed that our proposed approach had better query efficiency and shorter delay.
| Identifer | oai:union.ndltd.org:CHENGCHI/G0099753010 |
| Creators | 李欣諦, Lee, Hsin Ti |
| Publisher | 國立政治大學 |
| Source Sets | National Chengchi University Libraries |
| Language | 英文 |
| Detected Language | English |
| Type | text |
| Rights | Copyright © nccu library on behalf of the copyright holders |
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