一种基于双线性配对的移动自组网密钥协商协议

移动自组网是一种无固定网络基础设施、能量和计算资源有限的分布式动态网络,由于其无线传输链路的开放性,使得它非常需要一种计算和通信开销较小的密钥协商方案.本文基于椭圆曲线上双线性配对的概念,提出了一种适用于移动自组网的可认证密钥协商方案,既实现了邻居节点组成员身份认证的匿名性,也实现了需建立会话的节点之间的可认证密钥协商.分析表明,我们所提出的方案计算和通信开销比较小,安全性较好,非常适合于资源有限的移动自组网.     

基于在线聚类和检测成本的移动自组网异常检测

移动自组网具有无线信道、动态拓扑、缺乏基础设施和节点资源受限等特点,更易受到安全威胁,且无法部署复杂的安全协议和算法.为了有效检测移动自组网中的异常访问行为,提出了一种基于在线聚类和检测成本的异常检测方案TCDC.TCDC先在单个节点内对访问行为进行在线聚类和处理,然后在不同节点间通过基于检测成本的协同检测进一步确认访问行为.仿真实验表明,该异常检测方案能够有效地检测移动自组网中的异常行为,且消耗资源较少.     

移动自组网的安全路由协议

移动自组网（MANET）是自治的无基础设施的网络,它通过IP路由支持多跳无线通信,它被用于没有基础设施存在的动态变化的场景。多数自组网路由协议利用节点之间固有特性即相邻节点的信赖关系进行协作转发数据包。这种信赖模型使得恶意节点利用插入错误的路由更新、重放过时的路由信息、改变路由更新、或广播不正确的路由信息来瘫痪自组网。针对自组网的缺陷提出了一种认证路由策略来解决这些问题,同时也列举了仿真实验结果。     

移动自组网病毒传播模型及稳定性分析

考虑移动自组网中节点的移动特性,基于平均场理论提出移动自组网中病毒传播模型,并对建立的方程组进行平衡点存在性和稳定性分析,得出病毒传播的阈值及消亡条件,从而研究节点移动速度、通信半径、免疫成功率和免疫失效率对移动自组网中病毒传播行为和传播临界特性的影响。结果表明:当病毒基本再生数R0<1时,网络全局渐近稳定在无病毒平衡点;当R0>1时,网络全局渐近稳定在地方病平衡点。最后通过数值仿真验证了该模型的正确性。     

一种移动自组网的区域覆盖策略

提出了一种移动自组网的区域覆盖策略,可以使用最少的移动节点在某一区域内高效、快速地部署Ad Hoc网络。组网后移动节点全覆盖该区域,使区域内任意位置可以进行自由通信。仿真实验结果表明,该覆盖策略所形成的Ad Hoc网络抗毁性较强,从而证明了该策略在实际Ad Hoc组网中的有效性和可行性。     

自组网Random Waypoint移动模型节点空间概率分布的研究

Random Waypoint模型是自组网经常使用的移动模型,对这种移动模型下运动节点的空间概率分布进行了研究,得到了一维与二维区域的运动节点空间概率分布的精确公式,解决了自组网仿真模型的一个遗留问题．研究结果为基于Random Waypoint移动模型的自组网理论的推导、证明、仿真与应用提供了理论依据,对基于该模型的自组网仿真具有实践指导意义．     

移动自组网中基于身份的密钥管理方案研究

移动节点组成移动自组网(MANETs),MANETs没有固定的网络基础设施,也不存在中心信任机构,密钥管理是移动自组网安全最核心、最困难和最薄弱的环节,为了降低PKG密钥管理方案的通信开销,论文将ElGamal方案与预分配密钥管理方案相结合,提出了一种基于身份的预分配非对称密钥管理方案,在一定程度上降低了移动ad hoc网络非对称密钥管理中的通信开销[1～2],提高了网络安全.     

移动自组网中能量优化的路由算法研究综述

移动自组网是在没有中心基础设施情况下由一些移动用户自组织形成的多跳无线移动网络,通常为一些特殊环境提供临时通信便利.由于移动自组网中终端设备依赖于电池供电,为了延长节点的工作时间,要求尽量减少节点的能量消耗,从而延长整个网络的使用寿命.本文对当前存在的基于能量优化的单播和组播路由算法进行了分析和比较,阐述了目前亟待解决的主要问题和今后的研究方向.     

视频协同系统中时空感知的信息共享技术研究

用户节点通过多跳转发实现通信将会耗费大量的通信成本，研究设计了应用于办公自动化过程中的视频协同信息共享技术，该技术构造移动自组网(Mobile Adhoc Network, MANET)物理拓扑结构感知参数，同时提出时空感知的个性推荐算法。无拓扑感知和拓扑感知信息共享方法的平均邻居个数分别为5.6个和10.5个，提升率约为88.0%。对比于其他个性推荐算法，引入时间权重的推荐算法具有更低的节点命中个数和更高的平均跳数。该技术在实现时空感知的信息共享技术过程中将用户节点间的通信代价和用户间的兴趣相似度考虑在内，进而组建一个节点间数据通讯的高质量邻接网。通过这种方法能有效降低覆盖网络内部的通信量，维持良好的网络拓化结构，提高MANET网络的可扩展性，为用户提供更好的服务。     

移动自组网的访问控制技术研究

网络资源的共享与保护是移动自组网需要解决的关键问题之一。运用Voronoi图模型和quorum系统的思想,提出了一种移动自组网的动态路径quorum系统,设计了动态路径quorum的生成算法。基于移动自组网的动态路径quorum系统,提出了基于quorum系统的移动自组网的分布式访问控制机制,详细描述了节点的身份认证、网络资源的访问控制和权限管理协议。与传统的基于单个节点自身的访问控制机制相比,该访问控制机制具有较强的抗攻击能力和较高的可靠性,能够有效地提高移动自组网的资源共享与保护水平。     

一种文件共享系统的P2P网络架构设计

本文介绍的P2P网络文件共享系统为两层式多系统服务节点结构。系统实现了P2P架构下的各系统服务节点间文件协同检索、节点状态检测、各节点间的实时通信等技术问题,使文件共享系统发挥了P2P网络结构的技术优势。通过系统的开发实践,验证了P2P网络结构下的文件资源共享系统具有扩展方便、负载变化对系统影响较小等特点。     

基于博弈的MANETs信任模型研究

移动Ad-Hoc网络(MANET)是由一组带有无线收发装置的移动节点组成的无须固定设置支持的临时性的通信网络.MANETs具有开放的媒质、动态的拓扑结构、分布式的合作和受限的网络能力等基本特点.在MANETs中,节点之间相互信赖路由和转发数据包,节点间的合作是非常重要的.但是由于自私节点为了储存能量和其他资源,而不参与转发数据.由于MANETs通信没有第3方的中心认证,所以集中于强制合作是不适应的.基于博弈研究MANETs中的节点行为,根据节点的信誉度来获得资源,刺激节点共享资源和转发数据.提出了基于博弈理论的信任模型,鼓励包转发,约束自私节点.仿真结果表明该信任模型能够识别自私节点并且能在信任节点之间建立信任,提高了整个网络效率.     

The performance impact of traffic patterns on routing protocols in mobile ad hoc networks

As mobile ad hoc network (MANET) systems research has matured and several testbeds have been built to study MANETs, research has focused on developing new MANET applications such as collaborative games, collaborative computing, messaging systems, distributed security schemes, MANET middleware, peer-to-peer file sharing systems, voting systems, resource management and discovery, vehicular computing and collaborative education systems. The growing set of diverse applications developed for MANETs pose far more complex traffic patterns than the simple one-to-one traffic pattern, and hence the one-to-one traffic pattern widely used in previous protocol studies has become inadequate in reflecting the relative performance of these protocols when deployed to support these emerging applications.As a first step towards effectively supporting newly developed and future diverse MANET applications, this paper studies the performance impact of diverse traffic patterns on routing protocols in MANETs. Specifically, we propose a new communication model that extends the previous communication model to include a more general traffic pattern that varies the number of connections per source node. We study the performance impact of traffic patterns on various routing protocols via detailed simulations of an ad hoc network of 112 mobile nodes. Our simulation results show that many of the conclusions drawn in previous protocol comparison studies no longer hold under the new traffic patterns. These results motivate the need for performance evaluation of ad hoc networks to not only include rich and diverse mobility models as has been done in the past but also include diverse traffic patterns that stress a wide set of protocol design issues.     

A node management scheme for stable P2P service in mobile ad-hoc networks

In a mobile ad-hoc network, multiple number of nodes can communicate with one another without the need for an infrastructure network. It is used in many different types of places, including military zones and disaster or hazardous areas. In a mobile ad-hoc network, each node acts both as a main agent of communication and a relay. Furthermore, each gives a weakness to the network or is subjected to vulnerabilities from malicious attacks due to their distinctive qualities, namely mobility and limited power. Accordingly, in order for stable P2P service, it is important to maintain the reliability and connectivity of the network at a high level. With existing schemes, it has often been the case that when defective nodes or malicious nodes are detected, it also causes damage to normal nodes. In scheme suggested in this paper, those nodes that have temporary defects but otherwise normal and can recovered are kept in the network but those that are defective or malicious are eliminated from the network, using trust values. The simulation was carried out to evaluate the performance of the proposed method. As a result, the message transmission rate even if the impact of a malicious node than the conventional method was demonstrated increased keeping the stable network topology.     

An Energy-Efficient Resource Allocation Scheme for Mobile Ad Hoc Computational Grids

Due to recent advancements in mobile computing and communication technologies, mobile ad hoc computational Grids are emerging as a new computing paradigm, enabling innovative applications through sharing of computing resources among mobile devices without any pre-existing network infrastructure. Energy-efficient resource allocation is one of the key issues in mobile ad hoc computational Grids due to limited battery life of mobile nodes. To reduce energy consumption, we propose a hybrid power-based resource allocation scheme for allocation of interdependent tasks to nodes within mobile ad hoc computational Grid. The basic idea is to exploit dependencies and task type, and allocate interdependent tasks to nodes accessible at minimum transmission power. We also propose a power-based algorithm to search a group of closest nodes to allocate a set of interdependent tasks. Compared to traditional algorithms, complexity of proposed algorithm depends on number of transmission power levels rather than number of nodes within a Grid. The scheme is validated in a simulation environment using various workloads and parameters.     

Prevention of Black Hole Attack in Multicast Routing Protocols for Mobile Ad-Hoc Networks Using a Self-Organized Public Key Infrastructure

ABSTRACT

A mobile ad-hoc network (MANET) is an autonomous system of mobile nodes connected by wireless links in which nodes cooperate by forwarding packets for each other thereby enabling communication beyond direct wireless transmission range. Example applications include battlefield communication, disaster recovery operations, and mobile conferencing. The dynamic nature of ad-hoc networks makes them more vulnerable to security attacks compared with fixed networks. Providing security in mobile ad-hoc networks has been a major issue in recent years. Most of the secure routing protocols proposed by researchers need a centralized authority or a trusted third party to provide authentication. This destroys the self-organizing nature of ad-hoc networks. Black Hole attack is one of the routing attacks that occur in MANETs. In this attack, a malicious node uses the routing protocol to advertise itself as having the shortest path to the node whose packets it wants to intercept. In this article, we propose an enhanced certificate based authentication mechanism, where nodes authenticate each other by issuing certificates to neighboring nodes and generating public key without the need of any online centralized authority. The proposed scheme uses Multicast Ad-hoc On Demand Distance Vector Routing (MAODV) protocol as a support for certification. The effectiveness of our mechanism is illustrated by simulations conducted using network simulator ns-2.     

基于网络编码的手机用户群文件共享和同步

为了快速、准确的实现一跳范围内手机用户群的文件共享,以达到手机用户之间进行协同工作的目的,在Android操作平台上设计、实施了本系统。在系统中提出了基于网络编码的可靠广播算法来保证文件传输的可靠性和快速性,并通过基于机会编码的全网同步算法来实现任一时刻手机群中各节点文件同步。通过真实实验验证了系统中文件共享的时延并不会随着手机群中节点数目的增加而增加,文件同步时网络中数据量大幅度下降,因此相比并发共享等其它方法,系统提供了一种快速、可靠的手机群文件共享和同步方法。     

Energy efficient and robust allocation of interdependent tasks on mobile ad hoc computational grid

A mobile ad hoc computational grid is a distributed computing infrastructure that allows mobile nodes to share computing resources in a mobile ad hoc environment. Compared to traditional distributed systems such as grids and clouds, resource allocation in mobile ad hoc computational grids is not straightforward because of node mobility, limited battery power and an infrastructure‐less network environment. The existing schemes are either based on a decentralized architecture that results in poor allocation decisions or assume independent tasks. This paper presents a scheme that allocates interdependent tasks and aims to reduce task completion time and the amount of energy consumed in transmission of data. This scheme comprises two key algorithms: resource selection and resource allocation. The resource selection algorithm is designed to select nodes that remain connected for a longer period, whereas the resource assignment or allocation algorithm is developed to allocate interdependent tasks to the nodes that are accessible at the minimum transmission power. The scheme is based on a hybrid architecture that results in effective allocation decisions, reduces the communication cost associated with the exchange of control information, and distributes the processing burden among the nodes. The paper also investigates the relationship between the data transfer time and transmission energy consumption and presents a power‐based routing protocol to reduce data transfer costs and transmission energy consumption. Copyright © 2014 John Wiley & Sons, Ltd.