一种基于多移动Agent的P2P网络主动免疫机制

针对对等计算(P2P)环境中日益严峻的恶意代码传播及攻击问题,通过引入多移动Agent技术,提出一种适合P2P网络系统的主动免疫机制.基于多移动Agent的P2P网络主动免疫机制借鉴了生物免疫原理,并利用多Agent技术构建了面向不同功能的Agent,在中枢免疫节点与普通Peer之间、普通Peer与普通Peer之间实现了一种联合防御恶意代码的协作关系;还利用移动Agent技术实现了可以在整个P2P网络环境中漫游、承担主动探测恶意代码功能的Agent和携带免疫疫苗进行远程免疫的Agent,从而实现了对恶意代码的快速响应、分析处理和有效抵御,降低了恶意代码的危害程度.为了高效率地将免疫疫苗分发于网络各节点,还提出一种新的ET+扩散树模型以及基于ET+树的疫苗分发算法.首先分析了P2P网络恶意代码传播模型,然后介绍了基于多移动Agent的P2P网络主动免疫模型的体系结构及组件,以及基于ET+树的免疫疫苗分发算法,最后对算法性能进行了对比仿真验证.     

基于理性Agent的有序对等计算社会模型的研究

目前的对等计算(P2P)环境呈现出不稳定的无政府状态,存在的搭便车、公共悲剧以及虚假文件、共谋、不合作等问题使得各类闲置的资源得不到有效的利用,系统难以达到资源的最大共享,也得不到持续的、良性的发展.引入理性Agent技术,将节点改造为对等主体.对等主体被组织为若干个对等组,从而形成结构化的对等计算社会.为了使对等计算社会能够协调地、可持续地良性发展,重点研究对等计算社会中的信任机制,提出CMTM分类多级信任模型及改进的全局信誉度算法,并对系统和信任模型进行仿真实验予以验证.     

一种应用于对等网络的可信片上Agent模型

提出一种可信片上Agent模型（T-AoC）,它用于开放的、不安全的、面向网络边缘节点的对等网络环境中。为了有效保护应用Agent计算的系统中的Agent不被恶意Agent执行环境及Peer主机对Agent的攻击,T-AoC模型采用集成芯片作为硬件基础为Agent提供安全、可靠的执行环境。该芯片可安装在各需要运行Agent及其应用系统的对等网络节点主机上。基于信任关系转移的思想,增强对等网络节点之间的可信性,更有效地构建各种安全、可靠的基于Agent的P2P应用系统。具体描述了T-AoC模型的层次架构、工作原理和运行流程,以及T-AoC在P2P网络信息搜索系统的应用示范,分析了T-AoC的性能特点。     

一种基于移动Agent的云端(Cloud-P2P)数据复合销毁机制

云端融合计算(Cloud-P2P)融合了云计算与对等计算环境的所有节点资源,实现了最大范围的协作与资源共享。数据销毁机制是保障用户数据的安全性和可控性的重要措施之一,然而云端计算环境本身的特性也给数据的有效销毁带来了困难。针对云端数据存储系统对数据的主动销毁、定时销毁和自销毁等复合需求,提出一种基于移动Agent的数据复合销毁机制,该方法不依赖第三方,利用移动Agent技术实现对过期、废弃型数据及时、有效、灵活的销毁,并在恶意主体对数据实施攻击时主动实施防御性数据销毁,有效增强了用户数据的安全性。针对节点上数据的具体销毁,还提出一种新颖的“数据折叠”的数据覆写方法,它充分利用数据本身进行销毁,有效降低了系统的开销。     

移动P2P网络的协作缓存优化策略

移动P2P网络具有拓扑动态多变、节点资源有限、网络资源短缺的特点.如何合理地、高效地使用移动节点提供的协作缓存资源、增加移动节点间的协作来减少移动P2P的网络时延、节省带宽、防止拥塞是一个关键问题.深入研究了有限协作缓存--Cache资源的替换策略、重要数据的及时缓存和Cache资源的充分使用问题.并根据蚁群算法的思路,提出了一种基于信息素的Cache替换算法,建立了选取适当存储空间作为Cache的数学模型和推导.理论分析和仿真数据表明该算法能有效提高协作Cache资源的使用率,促进了移动节点间的协作,提高了移动节点从邻居节点获得资源的成功率,并减少了协作Cache资源请求的平均响应时间.     

多Agent系统的协作及强化学习算法研究

研究了多Agent环境下的协作与学习.对多Agent系统中的协作问题提出了协作模型MACM,该模型通过提供灵活协调机制支持多Agent之间的协作及协作过程中的学习.系统中的学习Agent采用分布式强化学习算法.该算法通过映射减少Q值表的存储空间,降低对系统资源的要求,同时能够保证收敛到最优解.     

TCLM-P2P:面向P2P社区的任务协作逻辑模型

P2P网络中广泛存在的"free riding"现象使其在任务协作领域的应用受到了极大制约.为了实现P2P网络环境下的有效任务协作,提出了一种具有激励机制的任务协作逻辑模型.基于Agent理论,首先给出了对等体、半对等体、P2P社区等概念;然后在合同网的框架下提出了面向P2P网络社区的任务协作逻辑模型TCLM-P2P(task collaborative logic model oriented to P2Pcommunity).相对于传统的任务协作模型,在合理的前提假设条件下,模型给出了模型公理和协作规则.该模型通过基于虚拟积分的协作算法实现了具有激励机制的P2P网络中的任务分配与协作.原型系统的实现及仿真实验结果表明TCLM-P2P模型具有可行性和有效性:不仅能够激励自利节点主动参与到任务分配与协作中;同时也能在一定程度上抑制节点的free riding行为,从而保障了P2P系统的有序工作.     

无线传感器网络中多移动Agent协同控制数据分流方法

针对移动Agent携带大量的数据包在网络上传输而造成的网络能量消耗过高、延迟时间过长和源节点工作寿命缩短等问题,提出了一种多移动Agent协同控制数据分流方法.首先,对树型结构为基础的多移动Agent行程规划算法进行分析;其次,建立网络能量消耗模型;最后,以能量消耗最小为原则,对树枝分叉处多移动Agent之间的数据和移动Agent迁移过程中的数据量两种情形进行合理分流.利用仿真将该方法与不分流的最小生成树多代理行程规划(MST-MIP)算法进行比较,结果表明该方法在能量消耗和任务延迟方面能够获得更好的性能,能量消耗最多可以降低35.2％,任务执行时间减少14.5％,传感器节点工作寿命也显著提高.     

基于组件的移动Agent平台设计与实现

将组件技术与移动Agent技术相结合可以有效地提高软件的重用性、灵活性及适应性,有利于大型分布式软件系统的开发.利用Javabean组件技术设计实现了一种移动Agent平台HBAgent,描述了HBAgent的设计思想和体系结构,给出了平台中的主要组件的概念,并通过一个应用实例说明了各组件的功能.该实例表明,HBAgent平台具有灵活、动态可扩充、支持离线计算等特点,可以为大型的应用开发提供一种面向Agent的开发平台.     

基于JADE的企业商务智能服务代理平台

为解决电子商务平台在异构和分布环境下计算实体的协作和协调、快速有效的信息收集及平台的智能化等问题,提出基于移动Agent在JADE上的企业商务智能服务代理平台体系结构模型和实现方法,给出基于多移动Agent的商务服务竞标算法流程和服务实体的行为交互过程,结合实际的应用验证,表明该服务代理平台系统在实际应用中的可行性与有效性。     

一种分阶段的P2P流媒体数据调度算法

针对当前P2P流媒体中各节点数据调度时独立获取数据而对提高节点间数据协作性考虑不足,导致服务器负载较重的问题,提出一种分阶段的数据调度算法。当多个节点将请求的数据中含有相同数据块时,各节点将分两个阶段合作的获取这些数据。第1阶段按照带宽相对大小各节点以合作的方式先各自获取数据的一个子集,第2阶段节点间再充分共享上一阶段已经获得的子集数据,协作地完成该轮调度的数据传输。仿真实验表明该算法可以提高节点间数据协作性,充分利用节点带宽资源传输媒体数据,提高系统可扩展性。     

DGTM: a dynamic grouping based trust model for mobile peer-to-peer networks

The special characteristics of the mobile environment, such as limited bandwidth, dynamic topology, heterogeneity of peers, and limited power, pose additional challenges on mobile peer-to-peer (MP2P) networks. Trust management becomes an essential component of MP2P networks to promote peer transactions. However, in an MP2P network, peers frequently join and leave the network, which dynamically changes the network topology. Thus, it is difficult to establish long-term and effective trust relationships among peers. In this paper, we propose a dynamic grouping based trust model (DGTM) to classify peers. A group is formed according to the peers’ interests. Within a group, mobile peers share resources and tend to keep stable trust relationships. We propose three peer roles (super peers, relay peers, and ordinary peers) and two novel trust metrics (intragroup trust and intergroup trust). The two metrics are used to accurately measure the trust between two peers from the same group or from different groups. Simulations illustrate that our proposed DGTM always achieves the highest successful transaction rate and the best communication overhead under different circumstances.     

P2P文件共享网络中信任管理系统的设计

针对P2P文件共享网络,设计了一个信任管理系统来评估、分发网络中各个实体的信任信息,并利用信任指导协作实体的选择,以隔离恶意实体,改善网络性能.之后的仿真实验证明了系统的有效性.     

基于对等网络的远程通信模型研究

对等网络,就是使PC或其它终端不通过服务器便可以直接在INTERNET上进行通讯的技术;该文提出了一种基于远程通讯模型,并对模型的结构、实现和远程定位地址的方法进行了讨论。     

A GroupTrust model based on service similarity evaluation in P2P networks

The open and anonymous nature of peer‐to‐peer (P2P) networks makes it an ideal medium for attackers to spread malicious contents, which in turn leads to lower quality of network services due to lack of effective trust management mechanism. To improve the quality of services (or transactions), this paper proposes a novel trust and reputation model, named as GroupTrust, based on peer group and evaluation similarity degree in P2P networks. In the proposed model, trust relationships between peers are divided into three categories: trust relationship within a peer group, trust relationship between different groups, and trust relationship between a peer in a peer group with another peer out of this peer group. The model presents the evaluation similarity degree under different context of services and gives local and global reputation computation. Experimental results demonstrate that this model can get more real trust value and deal with the malicious attacks efficiently by comparison with existing models. © 2010 Wiley Periodicals, Inc.     

基于移动agent的无结构P2P网络拓扑重连方法研究

为了提高无结构P2P网络中资源查找的效率,同时避免在资源查找过程中出现拥塞,提出了一种基于移动agent的网络拓扑重连方法。网络节点定期进行拓扑重连,同时通过收集其邻居节点的处理能力以及连通性等信息,指导移动agent有目的地在网络迁移,从而使移动agent及时发现网络节点上的拥塞,并使用拓扑优化机制降低节点上的负载。实验证明该方法能优化网络的拓扑结构,避免网络查询过程中发生拥塞,提高资源查找的效率,同时适应网络查询负载的动态变化。     

Mastering selfishness and heterogeneity in mobile P2P content distribution networks with multiple source download in cellular networks

The performance of Peer-to-Peer (P2P) content distribution networks depends highly on the coordination of the peers. This is especially true for cellular networks with mobile and often selfish users, as the resource constraints on accessible bandwidth and battery power are even more limitating in this context. Thus, it is a major challenge to identify mobile network specific problems and to develop sophisticated cooperation strategies to overcome these difficulties. Cooperation strategies, which are able to cope these problems, are the foundation for efficient mobile file exchange. The detailed performance of the strategies are determined by the peer capabilities and the peer behavior, such as the number of parallel upload connections, the selfishness, or the altruistic re-distribution of data. The purpose of this work is to evaluate and investigate different cooperation strategies which are based on multiple source download and select the best one for mobile scenarios with even leeching peers, i.e. peers which depart as soon as they have finished their download. The question arises whether the cooperation strategy can smoothen the overall performance degradation caused by a selfish peer behavior. As performance indicators the efficiency, fairness, and robustness of the cooperation strategies are applied. The considered scenarios comprise best-case (altruistic peers) and worst-case scenarios (selfish peers). We further propose a new cooperation strategy to improve the file transfer even when mainly selfish peers are present, the CycPriM (cyclic priority masking) strategy. The strategy allows an efficient P2P based content distribution using ordered chunk delivery with only local information available at a peer.     

一种基于信誉的P2P的评价模型

随着P2P(Peer to Peer)技术的广泛使用,判断请求节点是否可信变得非常重要。介绍了一种基于信誉的P2P的评价模型,用于计算在P2P过程中各个节点之间所产生的信誉度,从而判断请求节点是否可信。这种模型综合考虑了自身以往经验以及其它节点对请求节点的意见。通过实验,发现此模型不仅可以阻止恶意节点对正常节点的攻击,还可以有效地提高正常节点对有组织攻击的抵抗能力。     

An economic incentive model for encouraging peer collaboration in mobile-P2P networks with support for constraint queries

In mobile ad hoc peer-to-peer (M-P2P) networks, economic models become a necessity for enticing non-cooperative mobile peers to provide service. M-P2P users may issue queries with varying constraints on query response time, data quality of results and trustworthiness of the data source. Hence, we propose ConQuer, which is an economic incentive model for the efficient processing of constraint queries in M-P2P networks. ConQuer also provides incentives for peer collaboration in order to improve data availability. The main contributions of ConQuer are three-fold. First, it uses a broker-based economic M-P2P model for processing constraint queries via a Vickrey auction mechanism. Second, it proposes the CR*-tree, a dynamic multidimensional R-tree-based index for constraints of data quality, trust and price of data to determine target peers efficiently. The CR*-tree is hosted by brokers, who can sell it to other peers, thereby encouraging the creation of multiple copies of the index for facilitating routing. Third, it provides incentives for peers to form collaborative peer groups for maximizing data availability and revenues by mutually allocating and deallocating data items using royalty-based revenue-sharing. Such reallocations facilitate better data quality, thereby further increasing peer revenues. Our performance study shows that ConQuer is indeed effective in answering constraint queries with improved response time, success rate and data quality, and querying hop-counts.