Bayesian cognitive trust model based self-clustering algorithm for MANETs

With the introduction of mobile Ad hoc networks (MANETs), nodes are able to participate in a dynamic network which lacks an underlying infrastructure. Before two nodes agree to interact, they must trust that each will satisfy the security and privacy requirements of the other. In this paper, using the cognition inspired method from the brain informatics (BI), we present a novel approach to improving the search efficiency and scalability of MANETs by clustering nodes based on cognitive trust mechanism. The t...     

Ad Hoc网络中一种基于信任域值的IDS模型的设计

移动Ad Hoc网络由于具有开放媒质、动态拓扑和分布合作及能量受限等特点,特别容易受到攻击.在Ad Hoc网络中,每个节点充当路由器,寻找和保持到其他节点的路由.路由安全是保证Ad Hoc网络安全最重要的一环.本文采用决策支持系统中的信任机制将一种基于信任域值的IDS模型（IDS_trust）引入到Ad Hoc网络中,并提出了一种新的安全解决方案.     

移动自组网中基于多约束和协同过滤动态信任机制*

由于具有分布式特性,导致移动自组网容易遭受攻击。为了增强移动自组网的安全性,建立一套适合自组织、无认证中心的节点信任评估模型是非常必要的。因此,提出了一种移动自组网中基于多约束和协同过滤的动态信任机制。其主要思想是在根据节点自身的经历的基础上,采用一个带多约束的信任更新算法来评估直接信任。其中：时间衰减因子保证了信任度随时间进行衰减;奖励因子保证了良好的节点应受到奖励;惩罚因子保证了恶意节点应受到惩罚。另外,采用协同过滤技术来评估推荐信任,以此来阻止不诚实的推荐。通过定量评估分析和模拟仿真,结果表明所提出的方法比Bayesian模型能更精确地计算节点之间的信任度和提高移动自组网的安全性。     

RDSR-V. Reliable Dynamic Source Routing for video-streaming over mobile ad hoc networks

Mobile ad hoc networks (MANETs) are infrastructureless networks formed by wireless mobile devices with limited battery life. In MANETs for civilian applications, the network nodes may not belong to a single authority and they may not have a common goal. These MANETs are particularly vulnerable to selfish behavior, as some nodes may prefer saving resources to forward data. There are a few generic reputation-based systems for MANETs which could be used to enforce cooperation among nodes. However, we envision that the system performance can be highly improved by using cross-layer techniques that take into account the specific characteristics of each particular service. In this article, we propose a distributed and easy-to-implement routing mechanism based on reputation for the provision of MPEG-2 video-streaming services over MANETs. The main novelty that we introduce regarding the existent literature is that our proposal is service aware, that is to say, we consider the video-streaming service characteristics to develop a cross-layer design with the routing protocol. In addition, we do not introduce extra signaling overhead to monitor reputation because we use the standard video-streaming end-to-end signaling. Finally, simulation results show that our proposal clearly outperforms both standard Dynamic Source Routing (DSR) and OCEAN (a generic reputation-based mechanism).     

一种基于信誉评估与能量辅助约束的混合MANET分簇协议

如今在移动自组网(MANETs)中,应用更多地依赖于层次结构的支持.簇结构是MANET中应用最广泛的层次结构.然而既有的方法往往比较片面,并且缺乏可信机制的支持.提出了一种基于信誉评估与能量辅助约束的混合MANET分簇协议--HMCPRE,并深入分析了其极大独立性.HMCPRE方法充分考虑到了簇首选择所要求的能量前提和高信誉要求,有效扩展了HELLO消息;协议在每个节点上运行时计算复杂性小,迭代次数为O(1)级,簇首消息数为O(N)级,各种开销较小.模拟实验表明:HMCPRE协议能够有效抑制恶意不合作节点对网络的影响,减轻能量耗损对分簇造成的动荡,从而能形成更稳定的簇结构.     

Improved encryption protocol for secure communication in trusted MANETs against denial of service attacks

MANET(Mobile Adhoc Networks) possess the open system condition, absence of central server, mobile nodes that make helpless to security assault while conventional security components couldn’t meet MANET security prerequisites in view of restricted correspondence data transfer capacity, calculation power, memory and battery limit in addition to the vitality enabled environment. The trusted MANETs provide a reliable path and efficient communication but the secrecy of the trust values sometimes may be overheard by the masqueraders. Due to the need of the clustered MANETs the exchange of mathematical values remains to be a necessary part. In the proposed security of the trusted MANETs is focused so as to provide rigid and robust networks when additional resources are added. For clustering of the nodes LEACH protocol is suggested in which the CHs and CMs are fixed for the data transfer in the network. The energy is disseminated in the LEACH as to avoid the battery drain and network fatal. Hence to add resistance and to make an authentic network, the encryption and decoding is incorporated as a further supplementary to avoid the denial of service attacks, we have utilized DoS Pliancy Algorithm in which the acknowledgment based flooding attacks is focused. Likewise the encoded messages from the source node in one cluster can be recoded in the transmission stage itself to reproduce the messages. Contrasted with the past works, QoS of our proposed work has been made strides when tested with black hole and sink hole attacks. Simulation results shows that the DoS pliancy scheme works better and efficient when compared to the existing trust based systems.

     

基于信任管理机制的无线传感器网络虚假数据过滤方案

传统的无线传感器网络虚假数据过滤方案只对网络中的虚假数据报告进行过滤,网络中的妥协节点依然可以不断向网络中注入虚假数据,耗费网络资源。为了掐断虚假数据包产生的源头,提出了一种基于信任管理的虚假数据过滤方案。该方案通过分簇的方式,将多个被俘获的节点合谋伪造的虚假数据报告限定在一个簇内,同时引入信任管理机制来检测节点是否被妥协,从而隔离妥协节点。分析结果表明,该方案不仅能有效过滤虚假数据,还能隔离妥协节点,且具备很强的妥协容忍能力。     

基于信任机制的无线传感器网络可靠传输路由协议

在无线传感器网络中,针对异常事件监测时会出现大量数据发送引起网络拥塞、数据包无法可靠传输的问题,提出一种基于信任机制的可靠传输路由协议（RTRPT）。该协议提出了梯度分簇模型以选取簇头节点。在无异常事件发生时,通过转发能量阈值找出传输数据的邻居节点,进行数据传输。同时对这些节点进行转发概率与历史信任度计算得到直接信任度,再通过这些节点交互间接评价得到间接信任度。将直接信任度、间接信任度、距离度量和剩余能量作为评价指标,量化后通过熵权法得到邻居节点的综合信任。在异常事件发生时,节点仅需选择综合信任度最大的邻居节点作为转发节点,建立路由路径。使用OMNeT++进行仿真验证,RTRPT与TSRP、ESRT相比,在传输大量数据包时节点丢包率分别降低69.4%、52.7%;节点传输延迟分别降低53.6%、34.8%;网络生命周期分别延长32.5%、15.7%。仿真结果表明,RTRPT能有效减少丢包、降低传输延迟、延长生命周期。     

基于DHT策略的MANETs网络路由协议研究*

提出了一种分布式MANETs路由协议,该协议综合了基于DHT的应用路由协议Tapestry和网络层路由协议AODV的优点,使用随机路标算法对网络进行分簇,改进了Tapestry算法使其在分簇内节点间共享对象指针。仿真实验表明本协议可以有效避免覆盖层与物理层匹配失效的问题,在节点移动速度较快时仍能保持较高的路由查找成功率和较低的网络开销。     

An energy efficiency semi-static routing algorithm for WSNs based on HAC clustering method

In Wireless Sensor Networks (WSNs), energy efficiency is one of the most important factors influencing the networks’ performance. Through a well designed routing algorithm, WSNs’ energy efficiency can be improved evidently. Among various routing algorithms, hierarchical routing algorithms have advantages in improving nets’ robustness and flexibility, and it is more appropriate for large scale of networks. In this paper, some typical hierarchical routing algorithms are introduced, and their advantages and defects are analyzed. Based on these analyses, a new hierarchical routing algorithm with high energy efficiency named EESSC is proposed which is based on the improved HAC clustering approach. In EESSC, the sensor nodes’ residual energy would be taken into account in clustering operation, and a special packet head is defined to help update nodes’ energy information when transmitting message among the nodes. When the clusters have been formed, the nodes in cluster would be arrayed in a list and cluster head would be rotated automatically by the order of list. And a re-cluster mechanism is designed to dynamic adjust the result of clustering to make sensor nodes organization more reasonable. At last, EESSC is compared to other typical hierarchical routing algorithms in a series of experiments, and the experiments’ result which proves that EESSC has obviously improved the WSNs’ energy efficiency has been analyzed.     

A survey on trust based detection and isolation of malicious nodes in ad-hoc and sensor networks

Mobile ad-hoc networks (MANETs) and wireless sensor networks (WSNs) have gained remarkable appreciation and technological development over the last few years. Despite ease of deployment, tremendous applications and significant advantages, security has always been a challenging issue due to the nature of environments in which nodes operate. Nodes’ physical capture, malicious or selfish behavior cannot be detected by traditional security schemes. Trust and reputation based approaches have gained global recognition in providing additional means of security for decision making in sensor and ad-hoc networks. This paper provides an extensive literature review of trust and reputation based models both in sensor and ad-hoc networks. Based on the mechanism of trust establishment, we categorize the stateof-the-art into two groups namely node-centric trust models and system-centric trust models. Based on trust evidence, initialization, computation, propagation and weight assignments, we evaluate the efficacy of the existing schemes. Finally, we conclude our discussion with identification of some unresolved issues in pursuit of trust and reputation management.     

基于兴趣聚类的网格资源发现算法*

为了更有效地解决网格资源的搜索和定位问题,提出一种以P2P形式实现的、基于兴趣聚类的非集中式网格资源发现算法.算法采用被动学习方式,通过用户的访问历史抽取节点的兴趣属性,将节点按照兴趣属性划分为多个簇,资源发现请求在簇内朋友节点之间传播,查找失败后,将请求路由到与其兴趣最相似的其他簇内.仿真测试表明,算法稳定高效,相比传统算法在低开销情况下性能有显著的提高.     

能量均衡的无线传感器网络非均匀分簇路由协议

提出了一种能量高效均衡、非均匀分簇和簇间多跳路由有机结合的无线传感器网络分布式分簇路由协议DEBUC(distributed energy-balanced unequal clustering routing protocol).该协议采用基于时间的簇头竞争算法,广播时间取决于候选簇头的剩余能量和其邻居节点的剩余能量.同时,通过控制不同位置候选簇头的竞争范围,使得距离基站较近的簇的几何尺寸较小.这样,网络中不同位置节点之间的簇内和簇间通信能耗得以互相补偿.DEBUC采用簇间多跳路由,根据节点剩余能量、簇内通信代价和簇间通信代价,每个簇头在邻居簇头集合中运用贪婪算法选择其中继节点.仿真实验结果表明,DEBUC能够有效地节约单个节点能量、均衡网络能耗、延长网络生存周期.     

一种层次化的检索结果聚类方法

检索结果聚类能够帮助用户快速地浏览搜索引擎返回的结果.传统的聚类方法由于不能生成有意义的类别标签因此是不适合的,为了改善检索结果层次化聚类的效果,采用了基于标签的聚类算法,提出了将DF、查询日志、查询词上下文特征融合的类别标签抽取算法,并以抽取的标签构造基础类别图,通过GBCA算法构建层次化聚类结果.实验证明了多特征融合模型的有效性;GBCA算法在类别标签抽取和F-Measure两个评价指标上都比STC和Snaket算法有很大的提高.     

Clustering overhead and convergence time analysis of the mobility-based multi-hop clustering algorithm for mobile ad hoc networks

With the emergence of large mobile ad hoc networks, the ability of existing routing protocols to scale well and function satisfactorily comes into question. Clustering has been proposed as a means to divide large networks into groups of suitably smaller sizes such that prevailing MANET routing protocols can be applied. However, the benefits of clustering come at a cost. Clusters take time to form and the clustering algorithms also introduce additional control messages that contend with data traffic for the wireless bandwidth. In this paper, we aim to analyse a distributed multi-hop clustering algorithm, Mobility-based D-Hop (MobDHop), based on two key clustering performance metrics and compare it with other popular clustering algorithms used in MANETs. We show that the overhead incurred by multi-hop clustering has a similar asymptotic bound as 1-hop clustering while being able to reap the benefits of multi-hop clusters. Simulation results are presented to verify our analysis.     

Energy-efficient clustering in mobile ad-hoc networks using multi-objective particle swarm optimization

A mobile ad hoc network (MANET) is dynamic in nature and is composed of wirelessly connected nodes that perform hop-by-hop routing without the help of any fixed infrastructure. One of the important requirements of a MANET is the efficiency of energy, which increases the lifetime of the network. Several techniques have been proposed by researchers to achieve this goal and one of them is clustering in MANETs that can help in providing an energy-efficient solution. Clustering involves the selection of cluster-heads (CHs) for each cluster and fewer CHs result in greater energy efficiency as these nodes drain more power than noncluster-heads. In the literature, several techniques are available for clustering by using optimization and evolutionary techniques that provide a single solution at a time. In this paper, we propose a multi-objective solution by using multi-objective particle swarm optimization (MOPSO) algorithm to optimize the number of clusters in an ad hoc network as well as energy dissipation in nodes in order to provide an energy-efficient solution and reduce the network traffic. In the proposed solution, inter-cluster and intra-cluster traffic is managed by the cluster-heads. The proposed algorithm takes into consideration the degree of nodes, transmission power, and battery power consumption of the mobile nodes. The main advantage of this method is that it provides a set of solutions at a time. These solutions are achieved through optimal Pareto front. We compare the results of the proposed approach with two other well-known clustering techniques; WCA and CLPSO-based clustering by using different performance metrics. We perform extensive simulations to show that the proposed approach is an effective approach for clustering in mobile ad hoc networks environment and performs better than the other two approaches.     

Alliance-based clustering scheme for group key management in mobile ad hoc networks

Several protocols have been proposed to deal with the group key management problem in mobile ad hoc networks (MANETs). Most of these protocols organize the network into clusters to reduce the cost of key refresh or rekeying. Rekeying constitutes a challenging issue in group key management because it must be launched whenever the constitution of the group is altered following a leave or a join operation. However, cluster maintenance may also generate significative communication overhead. So, the clustering algorithm is an important factor in the performance of any key management solution. A clustering algorithm that ensures stable clusters in spite of mobility is very appreciable in mobile ad hoc networks. In fact, all the overhead due to the traffic generated by cluster adjustments and the related rekeying procedures will be saved. As far as we know, no existing clustering algorithm takes into account self-stabilization while relying on the mobility resilience of graph alliances. In this paper, we propose a fully distributed and self-stabilizing clustering algorithm for key management in MANETs where each cluster is an alliance.     

基于节点度和距离的WSN分簇路由算法

针对无线传感器网络(WSN)中节点的负载均衡问题,提出一种基于节点度和距离的WSN非均匀分簇路由算法。该算法在首轮成簇时采用了定时机制的簇头竞争方案,定时的长短取决于节点本身的节点度和距离基站的距离,且节点根据不同的竞争半径形成不同的簇。在首轮成簇结束后,簇的结构不再发生变化,而簇头的轮换则根据簇内节点的剩余能量和距离本簇质心的通信代价在簇内进行动态轮换。采用簇间多跳路由,根据节点的剩余能量、距离基站的距离、节点间通信代价和节点的转发热度来选择中继节点。仿真结果表明,该算法的网络生命周期与LEACH协议相比延长了2倍以上,与EEUC协议相比延长了13.97%,且均衡了网络的能量消耗。     

基于置信度的MANETs主观信任管理模型

移动自组织网络(MANETs)中,移动节点具有匿名性和高度自治的特点;并且由于缺乏对与之交互的节点的可信程度的知识,节点需应对交互过程中可能出现的威胁.另外,网络拓扑结构的改变或无线冲突的发生都可能导致作为信任值评估证据的样本空间不一定完整和可靠,使得现有的信任评估模型不太适用.提出了一种基于置信度的MANETs环境下的主观信任管理模型(CFSTrust),用于量化和评估节点的可信程度;给出了模型的数学表述和实现方法.运用模糊似然度和置信度对信任管理问题进行了建模,给出信任的评价机制,并提出了推荐信任关系的推导规则,构造了一个完整的主观信任管理模型.分析及仿真实验结果表明,CFSTrust模型较已有的基于证据理论的信任评估模型(TrustNet)更为有效,并为MANETs环境中的信任管理研究提供了一个有价值的新思路.