臺灣博碩士論文加值系統

由於近年來手持式行動設備與無線通訊的普及，地點感應服務(Location-aware Service) 漸漸受到重視，本論文專為此項服務而提出一階層式的網路架構，稱之為「地點感應式行動資訊整合網路 (Location-Aware Mobilized Information Integrated Networks (LAMIN))」，其基本原理是：使用者從衛星定位系統(GPS)取得目前所在地理位置，然後根據他對資訊類別的喜好與設定的服務品質，動態地自資料庫中擷取與該位置有關的資訊。此資料庫放置於Internet上，採用雙層的設計，頂層是中央伺服器存放著所有資料，底層是由一群區域伺服器所構成，暫存由中央伺服器透過有線網路所下載之資料，同時平均分擔透過無線網路傳送資料至使用者。在這樣的架構下，我們設計了多項管理機制，包括預載觸發、下載排程、資料快取管理等，而這些機制乃依據一套獎勵(reward)模型所建構，它的特色在於將行動環境下溝通的需求納入考量。透過模擬的結果我們得知，所提的機制的確能有效的達成─在行動環境下依使用者的偏好與服務品質獲取最有價值資訊的目的。

Due to the prevalence of handhold devices and wireless communications, the location-aware services have been gotten a lot of attention recently. In this thesis, we propose hierarchical network architecture, termed Location-Aware Information Integrated Networks (LAMIN), to provide such a service. In principle, a user gets his geographical location from Global Position System (GPS) and according to his personal information preferences and contracted Quality-of-Service (QoS), dynamically retrieve information associated with that location from a database. The database is deployed in Internet with two tiers. A central server archives the entire data collection. A group of regional servers cache data downloaded from the central server through wired links and evenly share the load of transmitting data to users through wireless links. Under this architecture, we design several management policies, such as pre-fetch triggering, download scheduling and data caching, based on a reward model, which stands out by taking the communication requirements in a mobile environment into account. The simulation results reveal that the proposed schemes can effectively achieve the objective of user’s gaining the most valuable information based on his personal preferences and contracted QoS in a mobile environment.

目錄
摘要 ……………………………………………………………I
ABSTRACT ………………………………………………………II
誌謝 ……………………………………………………………IV
目錄 ……………………………………………………………V
圖表索引 ………………………………………………………VII
1 緒論…………………………………………………………1
1.1 研究之背景、動機及目的……………………………1
1.2 章節概要………………………………………………8
2 文獻探討……………………………………………………9
2.1 預載……………………………………………………9
2.2 相關的置換策略………………………………………12
2.3 2G到3G的無線協定…………………………………14
2.3.1籃芽計劃 ………………………………………14
2.3.2 IEEE802.11b……………………………………14
2.3.3 GPRS ……………………………………………15
2.3.4 3G ………………………………………………15
3. 系統架構……………………………………………………18
3.1階層式快取架構………………………………………18
3.2各元件的功能及運作…………………………………20
4. 演算法設計…………………………………………………29
4.1 區域的劃分及觸發流程 ……………………………… 29
4.1.1 區域的劃分………………………………………29
4.1.2 觸發流程圖………………………………………32
4.2 CS到RS預載演法 ……………………………………33
4.2.1 CS到RS的預載設計量 …………………………33
4.2.2預載演算法 ………………………………………34
4.3 RS中的快取置換 ……………………………………41
4.3.1 快取置換的設計考量……………………………41
4.3.2 快取置換策略……………………………………42
4.4 RS到ME的下載策略 …………………………………45
5 模擬分析………………………………………………………48
5.1模擬的環境與假設 ……………………………………48
5.2 模擬的參數架構說明 …………………………………50
5.3 各實驗的模擬結果 ……………………………………52
5.3.1實驗1:比較預載的方式對hit ratio及hit reward ratio的影響 ……………………………………52
5.3.2 實驗2:不同等級的服務 ………………………57
5.3.3 實驗3:如何決定預載距離及下載距離 ………60
5.4 本章總結………………………………………………65
6 結論 …………………………………………………………66
參考文獻…………………………………………………………67

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