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1、毕业论文（设计）外文翻译题 目： 基于C+局域网聊天系统 学 院： 数理与信息学院 学生姓名： 陈霆 专 业： 计算机科学与技术 班 级： A07计算机 指导教师： 管林挺 起止日期： 2011.3.29至2011.6.18 2011年4月6日Paper1P2P trust modelSummary of the P2P network problems are analyzed, described the establishment of P2P network trust model needs.P2P network on the existing trust models are s
2、ummarized, pointing out the direction of future research.IntroductionWith the Internets widespread popularity, the rich end users system resources, as well as the rapid increase in network bandwidth, the traditional Client / Server Network Application Mode server performance bottlenecks and single p
3、oint of failure issue is not only limited the full use of end system resources,also increasingly unable to meet the new distributed applications.The P2P networks to work together, distributed information sharing, large-scale parallel computing such as showing the unique advantages of the new develop
4、ment to make it hot.P2P networks are willing to share resources on the node the basic assumption that each node share its own resources and from other nodes where the resources for their own needs.However, such individuals to provide resources for the public, and node behavior result in unconstraine
5、d mode of P2P network there are three problems.(1) ride (Free-Riding) problemFree-Rriding consumption of other nodes that node only contribution to the resources without sharing their own resources.To Gnutella P2P file sharing system, for example, 70% of the nodes is the Free-Rider.The latest monito
6、ring also shows that in the eDonkey file-sharing network, about 80% of the nodes is the Free-Rider.(2) Public Goods and sorrow (the Tragedy of the Commons) problemPublic Goods and sorrow means the network resources as a non-exclusive public resources are most uncontrolled use of P2P nodes, according
7、 to statistics, P2P traffic accounted for 60% of Internet Zong traffic flow, and the user is not the total number of significant growthcases, P2P traffic is still growing rapidly.In fact, P2P network users of its fundamental purpose is rational to maximize their utility, but does not consider the ne
8、tworks overall effectiveness.(3) not reliable services, and fraudP2P network, there are a large number of unreliable service quality, and fraud.To the many file-sharing application, for example, 25% of the documents were forged documents (Faked Files).This is similar to eBay in e-commerce, this is n
9、ot a reliable service and fraud to the user impact is more serious.Therefore, effective mechanisms must be designed to regulate the behavior of nodes in P2P networks to address these three issues, to improve the availability of P2P services to promote effective collaboration node and the rational us
10、e of network resources.Why is the trust modelNodes that have their own rights, self-organizing P2P network, how to regulate the behavior of the node? In fact, P2P networks provide real-world network environment of human communication, human-centered networks, and social networks with the same config
11、urationsex.The trust as an integral part of social existence, is the social network in the core of relations between people.Human society, reputation-based trust relationship with the incentive mechanism to restrict peoples daily behavior.Trust-based P2P network and the similarity of human social ne
12、tworks embodied in the P2P network between individuals interact with each other for each other left sporadic credit information; individual objects on the interaction with the full right to choose; individuals are often not the absolute valuereliability or quality of service that individuals can tol
13、erate a small amount of damage caused by the wrong choice, such as file-sharing application; individual obligation to the network to provide recommended information to other individuals.Therefore, we can describe P2P networks using the trust relationship between nodes, and to take trust-based incent
14、ive mechanisms to address these issues.(1) to provide differentiated services based on trust valuesIn file sharing P2P network, nodes on the network resources according to the contribution level, to provide differentiated services.For example, Kazaa nodes provide the resources and the ratio of consu
15、mption of resources into the system as a node in the level of participation and access to services as a priority of the node.BitTorrent nodes upload rate under each other to determine their own upload rate.EDonkey network node in accordance with the request of local trust values to set the node in t
16、he download queue priority.Malicious use of network resources on the node to punish.For example, proposed incentives RTBMa focus on the Gnutella network file transfer type when the bandwidth allocation problem, according to the contribution of the node on the network for distribution of bandwidth re
17、sources.When a node share data, contribute to stimulate nodes to increase share value.When the node from the node overload to download a file, contribution to reducing the value of the node to suppress the consumption of public resources.Differentiated services based incentives to encourage cooperat
18、ion between nodes, and the rational use of network resources, in order to address free-riding and the tragedy of public goods problem.(2) According to the trust value of node selection service providerNode can be based on trust values to choose to trade with each other.For example, in the eBay netwo
19、rk, high trust value to buy the products business, which encourage businesses to maintain good sales practices and improve reliability of products.Effectively inhibit the P2P network is not reliable services, and fraud.The concept of trustTrust is a multidisciplinary concept, describes specific situ
20、ations, an individual may have adverse consequences in the circumstances, want to believe that another individual has some ability to complete a task or a subjective belief.Close contact with the concept of trust the credibility of credit from the individuals social network, is based on observed pas
21、t behavior or past behavior of individual information and expectations on individual behavior.The difference between reputation and trust can I trust you because you have good credit or I trust you despite your credit is not good to show.This shows that the credibility of the stress that a group of
22、individuals or groups to a common level of reliability and trust more to emphasize that trust in the individuals subjective trust trusted party.Mentioned in this article refers to the trust the trust side of the trusted partys subjective trust, that trust in parties according to their own experience
23、 or to both the trusted partys reputation and resulting reliability of trusted parties.In resource sharing in P2P networks, reflecting the extent of not only the reliable nodes such as computing nodes, storage, network bandwidth and other aspects of the objective ability, and participate in P2P netw
24、orks with nodes in the behavior traits, such as duration of the node-line, friendly, and so on.P2P networks in e-commerce category, the sellers trustworthiness and product description, communication with the buyer, delivery time, delivery and related charges.In practical applications, the nodes will
25、 affect the credibility of all the factors that quantify the confidence and credibility of integrated reached node is not feasible.Therefore, under normal circumstances, the trust model in P2P networks, according to the node between satisfaction with the transaction to determine credibility.credibil
26、ity, trust and mutually beneficial relationshipShown in Figure 1, if node A has a reciprocal behavior of other nodes, then A will have a good reputation, so node A will be other nodes in the trust, and transaction reciprocal behavior by other nodes.The plan involves a trusted network of reciprocity,
27、 or you can call it incentive mechanism.As the social field, only when the behavior of the past affect the future (for sociology as the future of the shadow (Shadow of Future) phenomenon), people have incentive to build mutual trust.Therefore, the trust model and the incentive mechanism of interacti
28、on between the good, P2P networks can effectively promote the cooperation between nodes.Figure 1 credit, trust and mutually beneficial relationship between a simple modelTrust Model classificationIn P2P network, there are all kinds of attack models, including: fraud, counterfeiting, defamation, frau
29、d combined with a front-end node (head-end node generally provide reliable service, the cooperative nodes give a fair evaluation. However, these front-end nodetrying to give a high internal malicious nodes to disguise malicious node positive behavior) of the joint fraud, change the ID to re-enter th
30、e network node and the nodes intermittently to provide credible information and services, or the accumulation of credit to a certain height, the use ofits high trust value, fraud, slander or joint fraud attacks.Most of the current trust model focused on solving the problem of certain types of attack
31、s, according to the method to establish trust relationships can be broadly divided into the trust model based on trusted third parties, and based on the feedback / evaluation of two types of trust model.Trust Model based on trusted third partySuch trust model in the traditional PKI security system t
32、echnology, a small number of leaders through the network node to monitor the operation of the whole network, and regularly circular nodes or to punish violations.The legitimacy of these leaders node certificates issued by CA to be guaranteed.Such systems often rely on a small central node, so there
33、is a single point of failure, and scalability issues.Based on feedback / evaluation of the trust modelTrust model for P2P networks generally fall into this category, according to the different objects to be trusted, there is as resources to build the credibility and the credibility of the transactio
34、n nodes in two categories.The former focuses on P2P networks can access the informations credibility, and credibility of information providers do not establish direct contact.In this type of trust model, the nodes determine the reliability of the information, and gives a positive or negative feedbac
35、k rating, and further calculate the trust value.For example, in file-sharing application Kazaa, only consider the positive feedback to the data signature way to build credibility, that is, if the user accepted the authenticity of the information, then the signature, the information obtained more sig
36、natures, the authenticity of the morehigh.Such as resources, limited trust model to establish the credibility of information sharing applications, does not have broad applicability.Below the node for the transaction to establish the credibility of the trust model are explained.(1) global trust model
37、Trust model of such a network analysis and feedback of all transactions for each node to establish a unique credibility.The worlds largest auction site eBay by the end of trading, trading parties are given a positive, negative or neutral feedback rating, and use the number of positive minus the numb
38、er of negative rating reached a certain individuals credibility.The method is simple and easy to understand, but can not deal with the unfair trader is given feedback.S. Kamvar global trust model EigenTrust proposed transaction history according to the node to calculate the local trust, and trust in
39、formation to consider the recommendation of the node, through the iterative trust between nodes to achieve the spread of the trust, thus calculated for each node in the globalcredibility.W. Dou and EigenTrust similar to the proposed global trust model, to solve the EigenTrust credibility in solving
40、global problems when the existence of solutions.A. Yamamoto proposed a distributed trust model for P2P networks of trust between the nodes are modeled as Web page links, Pagerank algorithm using a distributed approach to calculating the trust value of nodes.But this model neglects the nodes and rela
41、tions of trust between the different nodes differ, their rationality is questionable.L. Xiong proposed PeerTrust to more effectively assess the trustworthiness of peers and describes a variety of malicious acts P2P community will not only deal satisfaction feedback for evaluating the parameters of t
42、he trust, taking the total number of transactions, feedbackcredibility, the transaction context factor, the community context factor.Simulation results show that the trust model can effectively inhibit the malicious node attacks.L. Mekouar made part of the distributed P2P network (such as KaZaa) the
43、 credibility of the management mechanism RMS_PDN.Super nodes in RMS_PDN passed between nodes in the trust evaluation, so that each super-node to its leaf node record of effective contribution to the system and the credibility as a leaf node.However, all the nodes directly RMS_PDN feedback vulnerable
44、 to malicious nodes of joint fraud attacks.Global trust model ignores the private trust of features for a particular node, other nodes on the trust of his values are the same.Simple global trust model vulnerable to malicious nodes joint fraud attacks.And complex needs of global trust model of cooper
45、ation between the processing nodes trust the information, computing and communication costs are higher.In addition, large-scale P2P network, each node in the global trust value computing the necessity and feasibility of further study.(2) the local trust modelOn P2P networks have mostly focused on th
46、e trust model provides a mechanism which nodes can share information for a given node, the local trust value calculation.Y. Wang proposed a P2P environment based on Bayesian network trust model.The trust model describes the main focus on different aspects of trust, which nodes can be based on differ
47、ent scenarios for on-demand access to different aspects of the performance of the node.The trust model can be adapted to smaller scale Gnutella network, or nodes of the Gnutella network interactive focus.S. Lee proposed a fully distributed way to store the users credit information.And other trust sy
48、stem is different in the NICE system, the node i trust information stored in other nodes of the services provided i satisfied with feedback, so trust in the information storage node motivated.L-Xiong PeerTrust proposed mechanism allows nodes to provide feedback according to the node with its own ind
49、ividual choices similar feedback to calculate a given node of the subjective reliability of this method to prevent fraud attacks the joint node, but in largescale P2P networks because of the sparsity of the transaction, there is not necessarily sufficient similarity with the individual nodes.Share information based on local trust model, shared access to information in two way
