以對等式為基礎的MPEG-4多人世界系統之實作

Abstract

由於多人連線世界促進遠端不同使用者之間的互動，諸如此類的應用如虛擬會議，遠距教學，線上遊戲已經愈來愈普及了。然而，大部分多人連線世界系統是以伺服器架構來實作，因此，其擴充性易受到伺服器本身的限制。本篇論文探討對等式架構對多人連線世界的研究。利用對等式架構來實作多人連線世界有以下好處：(1) 可以利用每個使用者來分享資源和內容(2)相對於伺服器架構，對等式架構提供更佳的擴充性和可靠性。在論文裡，我們設計和實作了一個對等式的MPEG-4多人連線系統。由於MPEG-4的豐富多媒體內容，其可以更易開發虛擬世界，因此我們選擇以MPEG-4來實作多人連線世界。而為了實現對等式多人世界，我們發展了(1)維護狀態一致性的方法(2)一個分散流量的方法。我們所實作的多人世界系統可以幫我們開發各種不同的更具擴充性的多人連線世界的應用。

Multi-user World Applications such as virtual meetings, distance learning, and on-line games, are gaining increasing popularity nowadays, as they facilitate interaction among remote users. However, most of the current multi-user world applications and frameworks are based on the server-centric system architecture. As a result, their performance scalability is limited by the servers. This thesis explores the peer-to-peer (P2P) networks as an alternative system architecture for Multi-user World Applications. There are many benefits of adapting the peer-to-peer architecture for Multi-user World: (1) contents and computing resources can be shared from both the center and the edge of the network, and (2) the peer-to-peer architecture can be made to provide better scalability and reliability than the traditional client-server architecture. In this thesis, we have designed and implemented a MPEG-4 Multi-user World framework based on the peer-to-peer model. We have chosen the MPEG-4 system due to its support for rich multimedia objects and the ease of virtual environment creation. To realize the P2P Multi-user-World framework, we have developed (1) a method to maintain the state consistency, and (2) an algorithm to fairly distribute the shared objects among heterogeneous peer nodes of varying capabilities. This P2P Multi-user World framework enables development of a variety of Multi-user World Applications with better scalability than the traditional client-server architecture.