基于RTI的统计分析方法检测与防御虫洞攻击

移动Ad hoc网是一种新型的无线移动网络,具有无中心、自组织、拓扑结构动态变化以及开放式通信等特性,使得Ad hoc网络易遭受攻击.虫洞攻击是针对Ad hoc路由协议的攻击,对Ad hoc网络造成的威胁最大.提出一种基于RTT(往返时间)的统计分析检测方法,在路由发现过程中,目的节点在返回路由应答(RREP)之前统计...     

双工k-ary n-mesh的虫孔路由分析

现代多处理机系统的互联网络多采用虫孔路由流控制。该文针对虫孔路由流控制和确定性路由算法下的双工ｋ－ａｒｙ ｎ－ｍｅｓｈ计算机互联网,采用倒推算法建立了求解消息平均传输延迟的分析模型,并建立仿真模型,理论分析与仿真结果基本吻合,表明该分析模型具有较好的精确度。     

基于蛀孔寻径的实时网络研究

文章从体系结构方面研究了多种系统中的通信问题,探讨了一种新的实时网络结构。系统利用蛀孔式寻径技术,缩短了通信延迟,使时延几乎与经过的结点数无关,弥补了一般机群系统的不足。     

裂缝性油藏酸液滤失模型研究

酸液在酸压裂缝内流动时,有少数较大的岩石孔隙或天然裂缝首先受到过量酸液的溶蚀而迅速增长形成蚓孔,使滤失主要在蚓孔内发生.因此研究天然裂缝性油藏酸液滤失,必须考虑酸蚀蚓孔的影响.基于裂缝性油藏酸压中酸液的流动反应特性,建立了酸蚀蚓孔的增长模型、酸液在蚓孔内流动反应模型和滤失的酸液在地层中流动模型,提出了便于现场应用的裂缝性油藏酸压滤失计算方法;就影响蚓孔增长及滤失的裂缝净压力、蚓孔密度和酸液粘度等因素进行了实例计算分析,对于现场酸压施工中有效控制酸液的滤失具有重要的意义.     

一种有效防御虫洞攻击的方法

由于无线传感器网络节点位置信息对网络的应用起着重要的作用,且传感器网络的资源有限,因此,针对DV-Hop定位算法的安全性能较差,定位过程中极易受到破坏性极大的虫洞攻击等缺点,提出了一种有效防御DV-Hop中的虫洞攻击的方法,在DV-Hop算法中引入了检测虫洞攻击及有效防御虫洞攻击的EPWDV-Hop算法,通过Matlab仿真软件进行模拟仿真。仿真结果表明,修改后的算法不仅提高了定位精度,而且很好地预防了算法中的虫洞攻击。     

Explanation of Performance Degradation in Turn Model

The Turn model routing algorithms for mesh interconnection network achieve partial adaptivity without any virtual channels. However, the routing performance measured by simulations is worse than with the simple deterministic routing algorithm. Authors have explained these results simply by uneven dynamic load through the network. However, this phenomenon has not been studied further. This paper investigates performance degradation with Turn model and drawbacks of partially adaptive routing in comparison with the deterministic routing, and it introduces some new concepts. Our simulations deal with individual channels and results are presented by 3D graphs, rather than by commonly used averages. An additional parameter—channel occupation, which is consistent with queuing theory commonly used in many proposed analytical models, is introduced. We also propose a new structure, the Channel Directions Dependency Graph (CDDG). It provides a new approach in analysis, helps in understanding of dynamic routing behaviour, and it can be generalized in other routing algorithms.     

Defending against wormhole attacks in mobile ad hoc networks

In ad hoc networks, malicious nodes can deploy wormhole attacks to fabricate a false scenario on the proximity relationship among mobile nodes. A classification of the attacks according to the format of the wormholes is proposed. This forms a basis to identify the detection capability of various approaches. An analysis shows that earlier approaches focus on the prevention of wormholes among neighbors that trust each other. As a more generic approach, we present an end‐to‐end scheme that can detect wormholes on a multi‐hop route. Only the trust between the source and the destination is assumed. The mechanism uses geographic information to detect anomalies in neighbor relations and node movements. To reduce the computation and storage overhead, we present a scheme called cell‐based open tunnel avoidance (COTA) to manage the information. COTA requires a constant space for every node on the path and the computation overhead increases linearly to the number of detection packets. We prove that the savings do not deteriorate the detection capability. Various schemes to control communication overhead are studied. The simulation and experiments on real devices show that the proposed mechanism can be combined with existent routing protocols to defend against wormhole attacks. Copyright © 2006 John Wiley & Sons, Ltd.     

碳酸盐岩酸蚀蚓孔等效渗透率影响因素研究

在碳酸盐岩储层在开发过程中,随着一段时间的生产,外来流体的侵入以及地层中的微粒会使得近井筒地带的储层受到污染从而渗透率下降,因此需要引入增产措施来改善地层渗透性。针对碳酸盐岩储层基质酸化形成的酸蚀蚓孔特点,基于基质酸化机理和分形理论,借助编制的VB软件,运用“点到圆”二分叉树状分形网络渗流模型,分析了二分叉网络长度分布分形维数、二分叉网络半径分布分形维数、二分叉网络分叉级数以及二分叉网络分叉角对蚓孔区无量纲等效渗透率的影响。     

Topological comparison‐based wormhole detection for MANET

Wormhole attack is considered one of the most threatening security attacks for mobile ad hoc networks. In a wormhole attack, a tunnel is setup in advance between two colluders. The colluders record packets at one location and forward them through the tunnel to another location in the network. Depending on whether or not the colluders are participating in the network functions, the wormhole attack can be further divided into two categories: traditional wormhole attack and Byzantine wormhole attack. Existing researches focusing on detecting traditional wormhole attacks can be classified into three categories: one‐hop delay‐based approach, topological analysis‐based or special hardware/middleware‐based approaches. Unfortunately, they all have their own limitations. Most of the researches detecting Byzantine wormhole attack are not addressing the Byzantine wormhole attack directly. Instead, they focus on observing the consequence after a Byzantine wormhole attack, like packet dropping or modification. In this paper, we propose to detect both traditional and Byzantine wormhole attacks by detecting some topological anomalies introduced by wormhole tunnels. Simulation results show that our scheme can achieve both high wormhole attack detection rate and accuracy. Our scheme is also simple to implement. Copyright © 2012 John Wiley & Sons, Ltd.     

一种动态分配输入队列的片上虫孔路由器结构

为了降低片上网络（NoC）由于虫孔缓冲结构排头（HoL）阻塞导致的性能损失,同时消除虚通道缓冲结构对可变长度报文表现出的缓冲区低利用率现象,本文采用虚拟通道技术提出一种动态分配输入队列（DAIQ）的片上虫孔路由器结构.该结构采用一种令牌表的方式支持虚拟队列深度与数量的动态分配,同时为了支持同一报文微片能够连续调度,本文还提出一种新颖的开关分配机制——SRRM,该机制在高负载下进一步改善了开关的延迟与吞吐率.仿真与综合的结果表明,相比传统虚通道流控的片上路由器结构,DAIQ路由器以50%的缓冲面积获得类似的性能,在0.13微米CMOS工艺下节约了30.18%的标准单元面积与384%的功耗.