摩擦轉(zhuǎn)矩補償在主動桿控制中的應(yīng)用外文翻譯

1、畢業(yè)論文（設(shè)計）外文翻譯題 目： 基于c+局域網(wǎng)聊天系統(tǒng) 學(xué) 院： 數(shù)理與信息學(xué)院 學(xué)生姓名： 陳霆 專 業(yè)： 計算機科學(xué)與技術(shù) 班 級： a07計算機 指導(dǎo)教師： 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 internet's widespread popularity, the rich end user's system resources, as well as the rapid increase in network bandwidth, the traditional client / server network application mode server performance bottlenecks an

3、d single point 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 n

4、ew development 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 un

5、constrained 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 lat

6、est monitoring 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) problem"public goods and sorrow" means the network resources as a non-exclusive public resources are most uncont

7、rolled use of p2p nodes, according 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 uti

8、lity, but does not consider the network's 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 s

9、imilar to ebay in e-commerce, this is not 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

10、 collaboration node and the rational use 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, a

11、nd social networks with the same configurationsex.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 people's daily behavior.trust-based p2p n

12、etwork and the similarity of human social networks 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 valuere

13、liability or quality of service that individuals can tolerate 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 re

14、lationship between nodes, and to take trust-based incentive 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,

15、kazaa nodes provide the resources and the ratio of consumption 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 wit

16、h the request of local trust values to set the node in the 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

17、the node on the network for distribution of bandwidth resources.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.differ

18、entiated services based incentives to encourage cooperation 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 valu

19、es to choose to trade with each other.for example, in the ebay network, 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 o

20、f trusttrust is a multidisciplinary concept, describes specific situations, 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

21、credit from the individual's social network, is based on observed past 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 go

22、od to show.this shows that the credibility of the stress that a group of individuals or groups to a common level of reliability and trust more to emphasize that trust in the individual's subjective trust trusted party.mentioned in this article refers to the trust the trust side of the trusted pa

23、rty's subjective trust, that trust in parties according to their own experience or to both the trusted party's 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, n

24、etwork bandwidth and other aspects of the objective ability, and participate in p2p networks with nodes in the behavior traits, such as duration of the node-line, friendly, and so on.p2p networks in e-commerce category, the seller's trustworthiness and product description, communication with the

25、 buyer, delivery time, delivery and related charges.in practical applications, the nodes will 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, acco

26、rding to the node between satisfaction with the transaction to determine credibility.credibility, 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 trans

27、action reciprocal behavior by other nodes.the plan involves a trusted network of reciprocity, 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

28、 have incentive to build mutual trust.therefore, the trust model and the incentive mechanism of interaction 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 classificatio

29、nin p2p network, there are all kinds of attack models, including: fraud, counterfeiting, defamation, fraud 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 malic

30、ious nodes to disguise malicious node positive behavior) of the joint fraud, change the id to re-enter the 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 join

31、t fraud attacks.most of the current trust model focused on solving the problem of certain types of attacks, 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 trus

32、t model.trust model based on trusted third partysuch trust model in the traditional pki security system technology, 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 n

33、ode certificates issued by ca to be guaranteed.such systems often rely on a small central node, so there 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 ob

34、jects to be trusted, there is as resources to build the credibility and the credibility of the transaction nodes in two categories.the former focuses on p2p networks can access the information's credibility, and credibility of information providers do not establish direct contact.in this type of

35、 trust model, the nodes determine the reliability of the information, and gives a positive or negative feedback 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, i

36、f the user accepted the authenticity of the information, then the signature, the information obtained more signatures, 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

37、 node for the transaction to establish the credibility of the trust model are explained.(1) global trust modeltrust model of such a network analysis and feedback of all transactions for each node to establish a unique credibility.the world's largest auction site ebay by the end of trading, tradi

38、ng parties are given a positive, negative or neutral feedback rating, and use the number of positive minus the number of negative rating reached a certain individual's credibility.the method is simple and easy to understand, but can not deal with the unfair trader is given feedback.s. kamvar glo

39、bal trust model eigentrust proposed transaction history according to the node to calculate the local trust, and trust information 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 globalcredi

40、bility.w. dou and eigentrust similar to the proposed global trust model, to solve the eigentrust credibility in solving 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 a

41、lgorithm using a distributed approach to calculating the trust value of nodes.but this model neglects the nodes and relations of trust between the different nodes differ, their rationality is questionable.l. xiong proposed peertrust to more effectively assess the trustworthiness of peers and describ

42、es a variety of malicious acts p2p community will not only deal satisfaction feedback for evaluating the parameters of the trust, taking the total number of transactions, feedbackcredibility, the transaction context factor, the community context factor.simulation results show that the trust model ca

43、n effectively inhibit the malicious node attacks.l. mekouar made part of the distributed p2p network (such as kazaa) the 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 c

44、ontribution to the system and the credibility as a leaf node.however, all the nodes directly rms_pdn feedback vulnerable 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.simpl

45、e global trust model vulnerable to malicious nodes joint fraud attacks.and complex needs of global trust model of cooperation 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 com

46、puting the necessity and feasibility of further study.(2) the local trust modelon p2p networks have mostly focused on the 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 networ

47、k trust model.the trust model describes the main focus on different aspects of trust, which nodes can be based on different 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 ne

48、twork interactive focus.s. lee proposed a fully distributed way to store the user's credit information.and other trust system 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 storag

49、e node motivated.l-xiong peertrust proposed mechanism allows nodes to provide feedback according to the node with its own individual 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

50、 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 ways: first, to the other nodes by flooding a request for trust, poor scalability of the method; the

51、 other is the mechanism through the use of p2p dht storage systems such aschord and other access, this method is not suitable for frequent node join and leave the system p2p system.moreover, such sharing of information based on local trust model is not suitable for management information between nod

52、es can not directly interact with some of the distributed p2p network.conclusionin the absence of an effective management mechanism in p2p networks, the establishment can suppress all the attack patterns of the trust model is very difficult, apart from the node to be able to suppress the attacks, th

53、e time of the establishment of trust model, trust model to fully consider whether the scale can be extendednature of trust in the trusted computing and information storage scalability, and trust in the process of information transmission bandwidth overhead problems.in addition, dynamic access to the

54、 network node frequent cases, the trust model of fault tolerance or robustness also needs to be stressed.in fact, in the p2p network trust model, the community should be fully learn the true reputation management system, different scenarios for the transaction to establish credibility for the node,

55、and nodes into a particular group to restrict and regulate the nodes xing wei.therefore, based on group reputation mechanism is the direction of future research, research work has been useful in the exploration of aspects, but still not mature.in addition, the model of incentive mechanisms based on

56、trust, not only to consider the p2p networks of cooperation between the internal nodes should also be considered p2p applications and networks of cooperation between other applications.for example, in p2p file sharing applications, when the network bandwidth utilization reaches a certain threshold,

57、still predatory on the node using the network resources to punish.p2p applications and networks in harmony with other applications, p2p applications is the development of long-term solution.journal of harbin institute of technologypaper2object landscapes and lifetimestechnically, oop is just about a

58、bstract data typing, inheritance, and polymorphism, but other issues can be at least as important. the remainder of this section will cover these issues. one of the most important factors is the way objects are created and destroyed. where is the data for an object and how is the lifetime of the obj

59、ect controlled? there are different philosophies at work here. c+ takes the approach that control of efficiency is the most important issue, so it gives the programmer a choice. for maximum run-time speed, the storage and lifetime can be determined while the program is being written, by placing the objects on the stack (these are sometimes called automatic or scoped variables) or in the static storage area. this places a priority on the speed of storage allocat