WWW環境中Inter-devices mobility系統實作

Abstract

隨著無線科技及電腦工業不斷的進步，使得無論在任何時間、任何地點人們皆可利用各種Device存取網際網路上的資源。另一方面，由於WWW的普及，WWW已經成為資訊傳遞最常使用的機制，而且可以預期的，使用者可能使用不同種類的devices(如：PDA、WAP手機、筆記型電腦或桌上型電腦)在任何世間、任何地點、為了某種資訊而瀏覽網際網路。 在本片論文，我提出了User Agent Proxy (UAP)能夠使內容提供者以及程式開發者可以不用面對不同Internet devices複雜性以及這些devices使用不同網路所造成的困擾，UAP基本上是使用者和Internet資訊系統的媒介，能提供通訊協定的轉換以並根據使用者的device型態及能力內容呈現的調整，除此之外UAP還記錄了使用使使用的device類型及能力並且記錄了使用者瀏覽的資料和狀態，透過UAP的協助，使用者能夠將目前這在瀏覽的內容從正在使用的device換到其他的device。 UAP是模組化的代理伺服器，所有的功能都可以隨時加入或移除，在本篇論文中我們主要致力在於下列兩個方面： 1.不同devices間的handoff：使用者能夠handoff瀏覽資料從目前使用的 device換到其他devices。 2.網頁格式的轉換以及內容呈現的調整：包含了格式的轉換(XML2WML)以 及呈現的修飾調整(如圖形的大小或彩色變灰白) UAP主要由三個元件所構成，包含了device agent，core agent以及content agent，device agent最主要是提供使用者端devices通訊協定的介面，Core Agent是整個UAP的核心，主要負責紀錄使用者目前所使用的devices種類，執行transcoding的動作並且呼叫適當的Agent處理特定的request。Content Agent主要的功能是取得Internet上的資源並記錄使用者瀏覽過的資料。

With the advance of wireless technologies and computer industries, it has become possible to access Internet anytime, anywhere and possibly with any devices through any access networks. On the other hand, with the growth of World Wide Web (WWW) population, WWW has become popular mechanism used for information dissemination. It should be expected that users might use different Internet devices (e.g., PDA, Web-enabled devices, note books, desktop computers) at different times and/or different locations for different purposes. In this thesis, we propose a User Agent Proxy (UAP) that can hide the complexity of the variety of Internet device and access networks from the content providers or application developers. UAP is essentially a middle-ware proxy that can perform protocol transformation and adjusts content presentation in accordance with the underlying transportation protocols and the capability of the user device. In addition, it also keeps tracking of the device a user preferring to use, and maintains the state of an active session. Through the assistance of UAP, a user may transfer an active browsing session from a device to another device that he prefers to use on a particular occasion. UAP is a flexible proxy and its functionality can be added or removed as needed. In this thesis, we focus only on the following two issues: 1. Inter-devices handoff: User can handoff a browsing session from a device to another device.. 2. Web page translation and presentation: including Syntax translation (XML2WML) and presentation adjustment ( image size, color to gray ) User Agent Proxy consists of three components: device agent, core agent and content agent. The Device Agent provides protocol interfaces to client devices through various access networks. The Core Agent is the core of User Agent Proxy. It keeps tracking of the user devices, maintains personalized device profiles, performs content transcoding and invokes the appropriate agent for a particular request. The Content Agent retrieves content from information infrastructure and cache web documents browsed by each person.