Research On Incentive Mechanism In Open Network Environments

With the development of computer and communication technologies,network environment has changed from a close network,which is comparatively static and faced with special organizations or user groups,to an open one that can be publicly accessed and faced with many dynamic users.As the representatives of open networks, Grid and P2P have become one of the most popular research fields all over the world.Open network is open,dynamic,heterogeneous,autonomic,equal and voluntary for resource sharing.Therefore,the rational peers in the network are self-interest and try to maximize their own benefit without considering the whole utility of network. Every peer hopes to use others' resources as many as possible,but contribute their own resources as few as possible,which leads to non-collaborative and dishonest behaviors in the network.As the network enlarges,fair sharing of the resources turns to be more intractable.Thus,incentive mechanism becomes an important issue of distributed system research area in such an open network.This dissertation discusses unreliable service usability and Free-riding problems in open networks resulting from peers' selfishness.It focuses on the researches that can stimulate rational and selfish nodes to share resources honestly,so that the network's integrated ability can be improved.Firstly,the dissertation summarizes the characters of open networks,describes and compares Grid and P2P which are the representatives of open networks,and presents the existing problems to elicit the research content of the dissertation. Subsequently,Chapter 2 introduces the fair sharing problem in open networks and summarizes reputation evaluation methods and trust models.This chapter also analyzes the advantages of using market mechanisms to manage open network resources,and bring forward the key of market incentive.Secondly,aiming at the severe information asymmetry problem,the dissertation introduces reputation to grid-based market resource trades and proposes reputation-aware transaction mechanisms.A reputation value is used to reflect the reliability of a resource;the users decide whether to use the resource in terms of the value.The reputation-aware aggregate market mechanism and double auction mechanism can both reduce the loss of the users resulting from unreliable service usability and resolve the information asymmetry problem.They can be applied in different situations. Then,in order to regulate the behaviors of selfish nodes,the dissertation proposes a reputation-based market incentive model.Different service levels can be traded for different prices.Service consumers buy service according to the system's recommendation derived from reputation mechanism.Service providers are modeled as learning agents.They learn from the environment and arrive at optimal dynamic service level policies that optimize their benefit in the long run.The proposed model can simultaneously guarantee the interests of both the providers and consumers,thus, it can stimulate the selfish nodes actively contribute and consume resources.Afterwards,the dissertation proposes a reputation model in P2P file-sharing system based on punishment.Aiming at the disadvantages of the recent reputation models,enlightened by economic theory,the dissertation introduces the concept of punishment to the research on reputation mechanism and gives a punishment-based reputation model.The model can restrict non-collaborative behavior efficiently and stimulate sharing.Finally,the dissertation proposes a scorc and monitoring based incentive mechanism in P2P media streaming system.Each peer obtains a contribution score in two ways:uploading data to others by itself and by its child peers.The peers with higher scores have better chances to download data,To maximize the score,a peer can choose to monitor its child peers to stimulate sharing.The proposed incentive mechanism can solve the long-term history score problem,increase the cooperative proportion and maintain higher system performance.From the present problems in open networks that the characteristics of network dynamicity,heterogeneity between peers and unreliable resources,this dissertation deeply studies the unreliable service usability and Free-riding problems,proposes reputation-based resource transaction mechanisms and a market incentive model, provides a reputation model based on punishment in P2P file-sharing system and a score and monitoring based incentive mechanism in P2P media streaming system.It gives the brand new view and fine perspective for solving the problem of open network resource sharing issues.