ART可適性及GPRS延遲的改善

Abstract

近年來，行動裝置的普及使得行動應用程式蓬勃發展，原本J2ME為行動應用程式執行的主流平台，近來隨著.NET CF的崛起，原有的行動應用程式必須移植到.NET CF平台，使得移植的需求愈來愈大，但兩平台互不相容，讓應用程式的移植面臨許多挑戰，而且兩平台之間缺乏自動或半自動轉換的工具，使得從J2ME移植行動應用程式到.NET CF變得費時且困難。 為了解決上述問題，我們將ART的應用範圍從原本的J2ME擴大到.NET CF平台，使用ART平台開發的行動應用程式只需要開發一次，便能在這兩個平台上顯示與操作。依ART架構，我們從網路連線、資料處理、使用者介面及使用者互動處理四個層面分析J2ME和.NET CF平台的異同，提出移植ART的方法。 在ART平台執行的應用程式需要透過網路將程式執行結果以ART訊息的方式從ART server傳送到ART client上顯示。GPRS是目前行動裝置最普遍的上網方式，但是由於GPRS的頻寬小且延遲時間長，使得ART訊息無法有效率的傳送到ART client。我們根據ART系統的特性，提出一個演算法來縮短ART 訊息在GPRS上傳送的時間。

Nowadays, the popularity of mobile devices enhances the development of mobile application. J2ME was the most popular platform for mobile applications originally, but the growth of .NET platform requires a lot of porting of mobile applications from J2ME to .NET platform. Since these two platforms are not compatible, it is challenging in terms of porting applications. Lacking of automatic or semi-automatic transform tool between these two platforms makes porting from J2ME to .NET becomes difficult and inefficient. To solve problems mentioned above, we extend the appliance of ART from J2ME to .NET platform. Therefore mobile applications developed by ART can be built just once and can display and operate in both platforms. We analyze the difference between J2ME and .NET in four parts: network communication, ART message handling, user interface display, and user interaction handling. We provide methods of porting ART depending on these four parts. Mobile applications running in ART send the executing result from ART server to ART client by ART messages through network. GPRS is the most popular network on mobile devices. Due to the low bandwidth and high latency of GPRS, transferring ART messages to ART client is inefficient. Based on the characteristics of ART system, we represent two algorithms to decrease the transferring time of ART messages through GPRS.