Incentives - Revision history

Itachi at 10:09, 30 July 2007

2007-07-30T10:09:08Z

← Older revision		Revision as of 10:09, 30 July 2007
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	:A user registers a number of spam-accounts to download from his main-account. Thus he transfers initial points given to new accounts to his main-account.		:A user registers a number of spam-accounts to download from his main-account. Thus he transfers initial points given to new accounts to his main-account.

			== EigenTrust ==

			EigenTrust is an incentive system based on traffic history of each peer. Uploading data to peer A increases the reputation of peer B from peer A's perspective. The reputation between all peers can be pictured using a trustmatrix <math>M</math> with elements <math>c_{i,j}</math>. <math>c_{i,j}</math> is peer ''j'' 's rank from ''i'' 's perspective related to normalized download volumes that ''i'' has received from ''j'' during a certain time period. In order to increase its local view of reputation, each peer takes into account his friends view (<math>M^2</math>). Thus the coverage of the rank matrix gets larger and it becomes less sparse. Continuing this step to its extreme (<math>M^{\infty}</math>), each column of <math>M</math> consists of the same values (= EigenTrust-vector), meaning that each peer has the same global view to other peers.
			{\| style="float:center; background:transparent; padding:0px; margin:0px;"
			\|[[Image:trustmatrix.jpg\|thumb\|center\|300px\|Downloadtraffic s mapped to a Trustmatrix M]]
			\|-
			\|}
			A peer with large global reputation (EigenRank) gets higher download bandwidth and less latency. Moreover, peers with large EigenRank are preferred to download from.

			=== Simulation Results ===
			Examined in [[The_Maze_Peer-To-Peer_System\|Maze-P2P-Network]], EigenTrust helped to punish colluding peers by branding them with low EigenRank. However, there are also some misinterpration.
			High reputation peers (super peers), which randomly download from "spam"-accounts, boost the EigenRank of these colluding peers.
			On the other hand, peers inside satellite clusters like university networks are unfairly punished. A university network as a whole consumes by downloading much more than it uploads. Neglecting and underestimating internal cluster traffic, EigenTrust underrates cluster peers EigenRank.

	== Tit-for-Tat ==		== Tit-for-Tat ==
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	Used in large scaled networks like [[The_Maze_Peer-To-Peer_System\|Maze]], Tit-for-Tat suffers from its small coverage. Even with long private history only a tiny percentage of peers is known to a user. Hence the majority are "blind" uploads, which bring a lot of opportunity to free-riders. This encourage peers to use "spam"-accounts than establishing long term trust relations.		Used in large scaled networks like [[The_Maze_Peer-To-Peer_System\|Maze]], Tit-for-Tat suffers from its small coverage. Even with long private history only a tiny percentage of peers is known to a user. Hence the majority are "blind" uploads, which bring a lot of opportunity to free-riders. This encourage peers to use "spam"-accounts than establishing long term trust relations.

			= Multi-Trust-Incentives =


	= Links =		= Links =

Itachi: Incentives (Maze-Network) moved to Incentives

2007-07-30T10:07:25Z

Incentives (Maze-Network) moved to Incentives

← Older revision	Revision as of 10:07, 30 July 2007
(No difference)

Itachi: Incentives in the Maze-Network moved to Incentives (Maze-Network)

2007-07-30T10:04:35Z

Incentives in the Maze-Network moved to Incentives (Maze-Network)

← Older revision	Revision as of 10:04, 30 July 2007
(No difference)

Itachi: Multi-Level-Incentives moved to Incentives in the Maze-Network

2007-07-30T10:02:28Z

Multi-Level-Incentives moved to Incentives in the Maze-Network

← Older revision	Revision as of 10:02, 30 July 2007
(No difference)

Itachi: /* EigenTrust */

2007-07-30T09:59:12Z

EigenTrust

← Older revision		Revision as of 09:59, 30 July 2007
Line 13:		Line 13:
	:A user registers a number of spam-accounts to download from his main-account. Thus he transfers initial points given to new accounts to his main-account.		:A user registers a number of spam-accounts to download from his main-account. Thus he transfers initial points given to new accounts to his main-account.

	== EigenTrust ==

	EigenTrust is an incentive system based on traffic history of each peer. Uploading data to peer A increases the reputation of peer B from peer A's perspective. The reputation between all peers can be pictured using a trustmatrix <math>M</math> with elements <math>c_{i,j}</math>. <math>c_{i,j}</math> is peer ''j'' 's rank from ''i'' 's perspective related to normalized download volumes that ''i'' has received from ''j'' during a certain time period. In order to increase its local view of reputation, each peer takes into account his friends view (<math>M^2</math>). Thus the coverage of the rank matrix gets larger and it becomes less sparse. Continuing this step to its extreme (<math>M^{\infty}</math>), each column of <math>M</math> consists of the same values (= EigenTrust-vector), meaning that each peer has the same global view to other peers.
	{\| style="float:center; background:transparent; padding:0px; margin:0px;"
	\|[[Image:trustmatrix.jpg\|thumb\|center\|300px\|Downloadtraffic s mapped to a Trustmatrix M]]
	\|-
	\|}
	A peer with large global reputation (EigenRank) gets higher download bandwidth and less latency. Moreover, peers with large EigenRank are preferred to download from.

	=== Simulation Results ===
	Examined in [[The_Maze_Peer-To-Peer_System\|Maze-P2P-Network]], EigenTrust helped to punish colluding peers by branding them with low EigenRank. However, EigenTrust leaves some room for misinterpretations.
	High reputation peers (super peers), which randomly download from "spam"-accounts, boost the EigenRank of these colluding peers.
	On the other hand, peers inside satellite clusters like university networks are unfairly punished. A university network as a whole consumes by downloading much more than it uploads. Neglecting and underestimating internal cluster traffic, EigenTrust underrates cluster peers EigenRank.

	== Tit-for-Tat ==		== Tit-for-Tat ==

Itachi: /* Multi-Trust-Incentives */

2007-07-30T09:55:34Z

Multi-Trust-Incentives

← Older revision		Revision as of 09:55, 30 July 2007
Line 33:		Line 33:
	Used in large scaled networks like [[The_Maze_Peer-To-Peer_System\|Maze]], Tit-for-Tat suffers from its small coverage. Even with long private history only a tiny percentage of peers is known to a user. Hence the majority are "blind" uploads, which bring a lot of opportunity to free-riders. This encourage peers to use "spam"-accounts than establishing long term trust relations.		Used in large scaled networks like [[The_Maze_Peer-To-Peer_System\|Maze]], Tit-for-Tat suffers from its small coverage. Even with long private history only a tiny percentage of peers is known to a user. Hence the majority are "blind" uploads, which bring a lot of opportunity to free-riders. This encourage peers to use "spam"-accounts than establishing long term trust relations.

	= Multi-Trust-Incentives =

	The major problem of private history based incentive systems is their coverage. Resolving it requires leveraging other reputable
	peers’ history which leads directly to the EigenTrust mechanism. Multi-Trust-Incentives try to mix both mechanisms.

	== Design of Multi-Trust-Incentives ==

	===Mathematical View ===
	===Implementation ===

	== Simulation ==

	===Coverage Experiment===
	===Lag-Hugger Experiment===
	===Satellite Cluster Experiment===

	== Evaluation ==

	= Links =		= Links =

Itachi: /* Multi-Trust-Incentives */

2007-07-30T09:50:11Z

Multi-Trust-Incentives

← Older revision		Revision as of 09:50, 30 July 2007
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	= Multi-Trust-Incentives =		= Multi-Trust-Incentives =

			The major problem of private history based incentive systems is their coverage. Resolving it requires leveraging other reputable
			peers’ history which leads directly to the EigenTrust mechanism. Multi-Trust-Incentives try to mix both mechanisms.

	== Design of Multi-Trust-Incentives ==		== Design of Multi-Trust-Incentives ==

Itachi: /* Multi-Trust-Incentives */

2007-07-30T09:46:57Z

Multi-Trust-Incentives

← Older revision		Revision as of 09:46, 30 July 2007
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	= Multi-Trust-Incentives =		= Multi-Trust-Incentives =

			== Design of Multi-Trust-Incentives ==

			===Mathematical View ===
			===Implementation ===

			== Simulation ==

			===Coverage Experiment===
			===Lag-Hugger Experiment===
			===Satellite Cluster Experiment===

			== Evaluation ==

	= Links =		= Links =

Itachi: /* Simulation Results */

2007-07-30T09:38:33Z

Simulation Results

← Older revision		Revision as of 09:38, 30 July 2007
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	=== Simulation Results ===		=== Simulation Results ===
	Examined in [[The_Maze_Peer-To-Peer_System\|Maze-P2P-Network]], EigenTrust helped to punish colluding peers by branding them with low EigenRank. However, ~~there~~ ~~are also~~ some ~~misinterpration~~.		Examined in [[The_Maze_Peer-To-Peer_System\|Maze-P2P-Network]], EigenTrust helped to punish colluding peers by branding them with low EigenRank. However, EigenTrust leaves some room for misinterpretations.
	High reputation peers (super peers), which randomly download from "spam"-accounts, boost the EigenRank of these colluding peers.		High reputation peers (super peers), which randomly download from "spam"-accounts, boost the EigenRank of these colluding peers.
	On the other hand, peers inside satellite clusters like university networks are unfairly punished. A university network as a whole consumes by downloading much more than it uploads. Neglecting and underestimating internal cluster traffic, EigenTrust underrates cluster peers EigenRank.		On the other hand, peers inside satellite clusters like university networks are unfairly punished. A university network as a whole consumes by downloading much more than it uploads. Neglecting and underestimating internal cluster traffic, EigenTrust underrates cluster peers EigenRank.

Wessendo: /* Links */

2007-07-26T18:24:42Z

Links

← Older revision		Revision as of 18:24, 26 July 2007
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	= Links =		= Links =
	* [http://research.microsoft.com/asia/dload_files/group/system/2006/Lian-maze06.pdf Robust Incentives via Multilevel ~~TitForTat~~]		* [http://research.microsoft.com/asia/dload_files/group/system/2006/Lian-maze06.pdf Robust Incentives via Multilevel Tit-For-Tat]