近年來，同儕運算(Peer-to-Peer, 簡稱P2P)的應用越來越廣泛，而許多採用P2P的軟體也相繼出現，供人使用，然而建構一個P2P的網路虛擬環境(Networked Virtual Environment，簡稱NVE)仍有許多問題需要解決，例如： 事件一致性(Event Consistent)、反應性(Responsibility)、安全性(Security)、擴展性(Scalability)、容錯性 (Reliability)，其中事件一致性又可分為因果關係一致性(Causal Consistent)跟順序一致性(Sequential Consistent)。在順序一致性中，多個使用者在爭奪一個資源時，資源的歸屬及使用者獲得相同的資訊是一個重要的課題。
因此本論文將提出一個建構在P2P NVE的資訊交換機制，目的是透過此一資訊交換機制，讓使用者在爭奪資源時，獲得相同的資訊，解決順序一致性的問題。根據上述目標，本論文提出的資訊交換機制使用了ACK以及優先權(Priority)的概念，確保所有人都收到相同的資訊。

In recently, there are many applications in a Peer-to-Peer environment. There are many problems in P2P Networked Virtual Environment such as event consistency、responsiveness、security、scalability、reliability.  Event consistency was divided  two problems such as causal and sequential consistency. In sequential consistency, when many avatars are competing a resources, who can get the resource, and avatars receive the same information are very important.

This thesis proposes an Information Exchange Mechanism to make sure that avatars received the same information, when avatars are competing a resource in a P2P NVE. The ACK and Priority mechanisms are proposed to solve this problem.

目錄	I
圖目錄	III
表目錄	V
第一章 緒論  	1 
1.1 研究動機  	1
1.2論文架構  	2
第二章 相關研究  	3
2.1網路傳送問題  	3
2.2 事件一致性	3
2.2.1 因果一致性  	4
2.2.2 順序一致性  	7
2.2.3 Critical Causality  	13
2.2.4 Timed Consistent  	13
第三章 系統架構  	15
3.1系統環境 	15
3.2名詞定義  	17
3.3 資訊交換機制  	21
3.3.1資訊交換  	22
3.3.2資訊的歸屬  	28
3.3.3例外處理 	29
第四章 模擬架構  	31
4.1模擬環境設定  	31
4.2 模擬數據  	31
第五章 結論  	36
5.1結論  	36
5.2未來發展  	36
相關文獻  	38
附錄-英文論文  	39

圖目錄
圖2.1  住戶發現火災示意圖	4
圖2.2  火災警報器發出聲音警告示意圖	4
圖2.3  火災警報器發出聲音警告示意圖	5
圖2.4  住戶發現火災示意圖	5
圖2.5  網路封包傳遞流程圖	6
圖2.6  火災警報器發出聲音警告示意圖	7
圖2.7  Client-Server確定資源歸屬示意圖	8
圖2.8  玩家互丟封包示意圖	9
圖2.9  封包delay示意圖	10
圖2.10  Avatar A傳送封包示意圖	11
圖2.11  Avatar A和Avatar B取得資源C示意圖	12
圖3.1  使用者AOI大小示意圖	16
圖3.2  競爭封包示意圖	19
圖3.3  競爭者名單封包示意圖	20
圖3.4  傳遞機制示意圖	21
圖3.5  傳送競爭封包示意圖	23
圖3.6   B、C、D、E回傳ACK示意圖	23
圖3.7  傳送競爭封包和接收ACK流程圖	24
圖3.8  等待時間變動流程圖	25
圖3.9  傳送競爭者名單示意圖	26
圖3.10  第一種資訊交換流程圖	27
圖3.11第二種資訊交換流程圖	28
圖3.12資訊交換例外處理流程圖	30
圖4.1  Avatar前三次取得資源示意圖	33
圖4.2  Avatar取得資源平均圖	34
圖4.3  Avatar依比率爭奪並取得資源示意圖	34

表目錄
表3.1  競爭封包的table	18
表3.2  競爭者名單的table	19
表3.3  競爭者名單封包的table	20
表4.1  16個avatars 的優先權及Unique ID	32

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