臺灣博碩士論文加值系統

網路快取機制被廣泛的應用在現有的網路架構中，其目的在於減少網路流量以及瀏覽延遲。大部分動態網頁由資料庫查詢結果所組成，使得其無法像靜態網頁一樣能夠被快取機制所快取。因此，本論文提出一個能將資料庫查詢結果部份快取的動態網頁設計方法並且利用AJAX程式機制來維護動態網頁資料的一致性。
依據更新資料欄位的時間性，本論文將其分為以下兩類：1. 非即時性更新資料、2. 即時性更新資料，而非即時性更新資料具有異動週期長或異動週期較短但具有極高的點閱率。因此，我們可將非即時性更新資料快取在網站上。針對於快取一致性將透過在快取檔名後加註時間章來確保資料是最新的。
本論文提出之方法所適用的情境為校園網路，旨在解決某一時段大量上網瀏覽查詢需求，導致網路雍塞或者停擺等現象。如：學生選課系統等。藉由本論文所提出的方法，非即時性更新資料能夠如靜態網頁一般，有效地被瀏覽器端及快取伺服器端所快取。在與傳統動態網頁相比較後，本論文所提出之方法可以減少即時性更新資料的大小以降低網路流量並且在首次查詢後減少網路瀏覽延遲的時間。

Web caches are widely used in the current Internet web infrastructure to reduce the network traffic and browsing latency. Since most of dynamic web pages are derived from the querying results of database, they are unable to be cached as static web pages. In this paper, we propose a dynamic web page design approach of building partially caching of the querying results and an Ajax programming mechanism to keep the dynamic data consistency.
Based on the temporal relation of updating data fields, we can split a table into two kinds of columns: cacheable and non-cacheable columns. The cacheable columns must have the property of a very longer updating cycle or a shorter updating cycle as well as a very higher browsing rate. Therefore, we can cache the data of those columns in the Website. Cache consistency is considered via a timestamp of cache file to make the dynamic data up-to-date.
With our proposed approach, it is focus on how to reduce the network load at the campus network, just like this constribution is a lot of students request their classlist and choose which class they want to select.the data of cacheable columns as a static web page can be efficiently cached by the current web browsers or web proxy servers. Comparing with the traditional dynamic web page, we can reduce the network traffic to the size of data of non-cacheable columns and the browsing latency to the time of querying of non-cacheable columns after the first time of web page browsing.

目 錄
第一章 緒論 1
第一節 研究動機 1
第二節 研究目的 2
第三節 論文架構 3
第二章 文獻探討 4
第一節 動態網頁技術 4
第二節 快取機制 5
第三節 動態網頁快取的相關研究 9
第三章 動態網頁快取機制設計 11
第一節 動態網頁快取設計架構與流程 11
第二節 建構實例 17
第四章 實驗與分析 25
第一節 實驗環境 25
第二節 實驗流程 26
第三節 實驗分析 27
第五章 結論 32
參考文獻 33

圖 次
圖2.1 用戶端與網站伺服器端溝通圖 6
圖2.2 典型的三層式架構：包括Client、Web Server和AP Server 6
圖2.3 正向快取代理伺服器 8
圖2.4 反向快取代理伺服器 8
圖2.5 通透性快取代理伺服器 9
圖3.1 建立動態網頁快取機制之設計流程圖 11
圖3.2 對照組之程式關聯圖 17
圖3.3 實驗組之程式關聯圖 18
圖3.4 對照組Result.asp與實驗組wctf_myResult.htm程式碼比較 19
圖3.5 對照組與實驗組處理查詢結果方式 19
圖3.6 刪除js快取資料檔提示 24
圖4.1 實驗流程圖 26
圖4.2 所佔頻寬長條圖 28
圖4.3 單一使用者查詢的傳統動態網頁、新建立快取動態網頁、和已建立快取動態網頁等三種條件下的網站平均查詢處理時間 29
圖4.4 10個使用者同時查詢的傳統動態網頁、新建立快取動態網頁、和已建立快取動態網頁等三種條件下的網站平均查詢處理時間 30

表次
表3.1 資料庫查詢結果範例 13
表4.1 封包數及頻寬表 28
表4.2 js快取資料檔 29

參考文獻
1.K. Y. Wong (2006), "Web Cache Replacement Policies: A Pragmatic Approach," IEEE Network, January/February 2006, pp. 28-34,.
2.Y. K. Chang, Y. R. Lin, and Y. W. Ting (2006), "Caching Personalized and Database-related Dynamic Web Pages," IWNAS 2006, pp.149-156, .
3.A. Bühmann, T. Härder, and C. Merker (2006), "A Middleware-Based Approach to Database Caching," ADBIS 2006, Thessaloniki, Greece, Sep. 2006, pp. 184-199.
4.C. Bornhovd, M. Altinel, S. Krishnamurthy, C. Moha, H. Pirahesh, and B. Reinwald (2003), "DBCache: Middle-tier Database Caching for Highly Scalable e-Business Architectures," ACM SIGMOD 2003, San Diego, California, USA, Jun. 2003, pp. 662 – 662,.
5.B. Wu, and A. D. Kshemkalyani (2006), "Objective-Optimal Algorithms for Long-Term Web Prefetching," IEEE Transactions on Computers, vol. 55, no. 1, Jan. 2006, pp. 2-17.
6.J. Ma, and Z. Gu (2006), "Finding Shared Fragments in Large Collections of Web Pages for Fragment-based Web Caching," The Fifth IEEE International Symposium on Network Computing and Applications (NCA’06), Cambridge, MA, USA, Jul. 2006, pp. 251-254.
7.M. Altinel, C. Bornhövd, S. Krishnamurthy, C. Mohan, H. Pirahesh, and B. Reinwald (2003), "Cache Tables: Paving the Way for an Adaptive Database Cache," VLDB Conference 2003, pp. 718–729
8.K. Amiri, S. Park, R. Tewari, and S. Padmanabhan (2003), "DBProxy：A Dynamic Data Cache for Web Applications." ICDE Conference 2003, pp. 821–831
9.P. Larson, J. Goldstein, and J. Zhou (2004), "MTCache: Mid-Tier Database Caching in SQL Server," ICDE Conference 2004.
10.S. V. Nagaraj (2004), "Web Caching and Its Applications," Kluwer Academic Publishers.
11.A. Bühmann, T. Härder (2004), "Database Caching: Analysis of Constraint-based Approaches Exemplified by Cache Groups," Grundlagen von Datenbanken, pp. 38-42.
12.http://www.json.org.
13.http://www.w3.org/XML/
14.蔣坤霖(2003), "動態網頁快取系統之設計與實作", pp. 13-16.