Kademlia[1]提出了以二進位數列組成的ID，搭配XOR的機制來建立邏輯距離，並用此為基礎構建一個虛擬網絡。但此虛擬網絡在搜尋上無法同時考慮實體網絡的狀況，如此將導致最後的結果，在實際網絡中可能是距離較遠的節點，其產生的延遲將降低往後操作的效率。因此本論文將使用ping值代表實際距離，使得搜尋能同時考慮ping值，在保持原Kademlia的特性下，取得較有效率的結果，稱作PRKad。
　　從模擬實驗的結果看來，PRKad雖然增加較多的跳數，但可以有效的取得ping值較低，也就是實際距離較近的節點。

　　Kademlia[1] provides a concept of using XOR between ID to present logical distance. As Kademlia uses logical distance to search, it cannot take physical distance into consideration, which can lead the result to be the closest in logical, but the farthest in physical.
　　In this paper, ping rate is used to represent the meaning of physical distance, and construct a physical network in Kademlia. The operations like lookup and search will take logical and physical distance into consideration at the same time, called PRKad.
　　The simulation result shows that PRKad can actually automatically choose the more efficiency nodes, which means the close nodes in physical network, to decrease the time using of the following operations.

誌謝 i
摘要 iii
Abstract iv
目錄 v
圖次 viii
表次 x
第一章 Introduction 1
1.1 background and Motivation 1
第二章 Relate work 3
2.1 CAN 3
2.1.1 Join 4
2.1.2 Leave 4
2.1.3 Lookup 4
2.2 Chord 4
2.2.1 Finger table 5
2.2.2 Join 6
2.2.3 Leave 7
2.2.4 Lookup 8
2.3 Chord2 9
2.3.1 Super node selection 9
2.3.2 Conduct ring construction 10
2.3.3 Join 12
2.3.4 Leave 13
2.3.5 Lookup 13
2.4 Pastry 14
2.4.1 Join 16
2.4.2 Leave 16
2.4.3 Lookup 16
2.5 Tapestry 17
2.5.1 Join 17
2.5.2 Leave 17
2.5.3 Lookup 18
第三章 Kademlia 19
3.1 k-bucket 19
3.3 Kademlia tree 20
3.3.1 Join/Leave 23
3.4 Protocol 23
3.4.1 Lookup 23
3.4.2 Publish 24
3.4.3 Search 24
3.5 Problem Definition 25
3.6 Relate Work 26
第四章 PRKad 28
4.1 PR tree 28
4.1.1 Join/Leave 30
4.2 Protocol 31
4.2.1 Bootstrap 31
4.2.2 Lookup 31
4.2.3 Publish 32
4.2.4 Search 33
第五章 Simulation 34
5.1 Design 34
5.1.1 Ping/Latency 34
5.1.2 Simulation Message 35
5.1.3 Simulation Time 36
5.1.4 Simulation Set 37
5.2 Simulation Result 40
5.2.1 General Simulation 40
5.2.2 Parameter Set Simulation 44
5.2.3 Other Simulation 45
第六章 Conclusion 46
Reference 47
Appendix 55

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