Towards A Game Theoretic Understanding of Ad-Hoc Routing

In this paper we present a new application of game theory, in which game theoretic techniques are used to provide a rigorous underpinning to the analysis of ad-hoc routing protocols. The explosion of interest in ad-hoc networks over the last few years has resulted in a very large number of routing protocols being proposed. Despite this, the science of analysing routing protocols is still relatively immature, and the question that remains is how to decide “how good” a given protocol is. We propose a game theoretic approach as a potentially effective means of answering this question. The conceptual mapping of routing into a game is, we believe, natural and simple. Furthermore, game theory provides an extensive repertoire of tools to analyse key properties. The paper describes how routing techniques can be modelled as games and presents some analytical results.     

用于可重构硬件容错过程的辅助布线电路设计

目前可重构硬件的容错机制大多采用重新布局布线的方法,但是需要很长的重布线时间,难以满足工程应用的需要.为此,提出一种支持可重构单元阵列快速容错的辅助布线电路,该电路结构由二维的辅助布线模块构成,每个辅助布线模块可以读取并修改所在可重构单元的可编程开关配置数据.可重构单元阵列容错时,辅助布线电路代替外部软件执行故障线网的取消和线网重布线过程.以4位并行乘法器为例,证明了在系统容错时辅助布线电路可以有效地加速故障线网取消和重布线过程.     

Dynamic Game Theoretic Model of Multi-Layer Infrastructure Networks

Due to similarities in terms of network structure and interactions among them, most infrastructure systems can be viewed as coupled layers of a generalized transportation network in which the passenger, freight, data, water, and energy flows are the commodities in the different layers. The coupling is due to the varying degrees of interactions among these layers in terms of shared physical networks, budgetary constraints, socio-economic environments, environmental concerns, information/other resources, and in particular, functional interdependencies. However, these interactions are normally ignored in the engineering planning, design and analysis of infrastructure systems. Identifying and understanding these interactions using a holistic perspective can lead to more efficient infrastructure systems. This paper presents a preliminary network flow equilibrium model of dynamic multi-layer infrastructure networks in the form of a differential game involving two essential time scales. In particular, three coupled network layers—automobiles, urban freight and data—are modeled as being comprised of Cournot-Nash dynamic agents. An agent-based simulation solution structure is introduced to solve the flow equilibrium and optimal budget allocation problem for these three layers under the assumption of a super authority that oversees investments in the infrastructure of all three technologies and thereby creates a dynamic Stackelberg leader-follower game.     

基于无线多跳网络有限理性节点博弈分析

无线多跳网络的时空动态性,使得网络中的节点对服务质量的需求具有多样性,不同需求的变化促使节点扮演"有限理性"的参与者,去适时改变效用分析。本文基于博弈理论,结合"智猪博弈"典型模式,设计合理机制激励节点依据"杠杆原理"分析群体与个体之间的利益关系,使节点根据自身的实际需求寻求效用与通信代价之间的平衡点。     

基于非合作博弈的无线网络路由机制研究

无线网络因其分布性、独立性、移动性等特点,网络性能容易受到自私节点的影响.文中综述了无线网络中因自私节点的存在而带来的一些关键问题,特别对含有自私节点的无线环境中基于非合作博弈理论的路由机制进行了分析和研究.为了解决网络中自私节点的问题,目前研究人员主要提出了两种机制:基于信任度的机制和基于非合作博弈的激励机制.文中对上述两类机制进行了总结和分析,特别地,针对无线自组织网络和无线网状网络中各种激励机制进行了详细的研究.网络编码作为一种有效的技术有助于提高无线网络的性能,文中探讨了基于网络编码的优化埘含有自私节点的无线网络性能的影响.同时还分析了非合作无线网络中节点共谋的问题,最后提出了当前非合作无线网络研究中存在的理论挑战及潜在的热点方向.     

Fault Tolerance and Recovery for Group Communication Services in Distributed Networks

Group communication services (GCSs) are becoming increasingly important as a wide field of promising applications has emerged to serve millions of users distributed across the world.However,it is challenging to make the service fault tolerance and scalable to fulfill the voluminous demand of users in a distributed network (DN).While many reliable group communication protocols have been dedicated to addressing such a challenge so as to accommodate the changes in the network,they are often costly or require complicated strategies to handle the service interruptions caused by node departures or link failures,which hinders the service practicability.In this paper,we present two schemes to address the challenges.The first one is a location-aware replication scheme called NS,which makes replicas in a dispersed fashion that enables the services on nodes to gain immunity of failures with different patterns (e.g.,network partition and single point failure) while keeping replication overhead low.The second one is a novel failure recovery scheme that exploits the independence between service recovery and structure recovery in time domain to achieve quick failure recovery.Our simulation results indicate that the two proposed schemes outperform the existing schemes and simple alternative schemes in service success rate,recovery latency,and communication cost.     

计算机网络的一实体安全体系结构

提出了计算机网络的一种实体安全体系结构（ESA）。文中描述了计算机网络的组成实体,并讨论了各实体的安全功能分配。基于ESA,提出了基于政策的安全管理（PBSM）的概念,其中包括三层安全政策的定义：组织抽象安全政策、全局自动完全政策、局部可执行安全政策,并提出了PBSM的三个管理环节：制定、实施与验证,把网络作为一个整体来管理,实现安全管理的系统化和自动化。应用实体安全体系结构,分析了现有网络安全服务的不足和安全管理中存在的问题,指出了实现ESA的进一步研究工作。     

集散系统通信网络的容错性策略及其应用

本文讨论了集散型控制系统通信网络容错性的几种策略，指出了在不同网络拓扑结构下应采用的最佳策略，这对工业现场控制提高系统的可靠性和有效度有着重要的实际意义。     

无线传感器网络中连通问题的容错性分析

在确定部署的无线传感器网络中,由于节点本身的脆弱性及应用环境的恶劣性,在部署及研究分析网络时应该考虑到网络节点出错的因素.当网络连通概率和网络规模给定时,网络节点的出错概率应在多大的范围之内;在给定的网络规模和节点出错概率下,网络的覆盖与连通情况如何,这些都是本文分析研究的内容.本文首先定义了一个比较规范的三角形(Triangular)模型,研究了在确定部署情况下,网络节点出错的概率与网络的覆盖概率之间的关系,然后借助"k阶子网"的概念分析了Triangular网络的连通容错性,最后通过模拟试验,对前面通过理论分析计算出的传感器网络连通概率的下界和节点出错概率的上界的可信性进行验证,同时将Triangular拓扑的网络与网格状网络进行比较.     

A Game Theoretic Approach to the Analysis of Dynamic Networks

A model of dynamic networks is introduced which incorporates three kinds of network changes: deletion of nodes (by faults or sabotage), restoration of nodes (by actions of “repair”), and creation of nodes (by actions that extend the network). The antagonism between the operations of deletion and restoration resp. creation is modelled by a game between the two agents “Destructor” and “Constructor”. In this framework of dynamic model-checking, we consider as specifications (“winning conditions” for Constructor) elementary requirements on connectivity of those networks which are reachable from some initial given network. We show some basic results on the (un-)decidability and hardness of dynamic model-checking problems.     

计算机控制系统的容错技术

计算机控制系统的可靠性设计是实现柔性智能控制所面临的一个重要课题，而容错技术是系统可靠性设计的关键技术。本文在分析计算机系统可靠性设计的基础上，综述了容错技术的发展、研究的主要内容及实现的主要方法，对常用的几种容错结构进行了比较和评价。指出了对计算机系统进行容错设计必须解决的主要问题。     

基于博弈论的信息安全技术评价模型

信息安全在企业信息系统建设中越来越重要,如何评价信息安全技术成为当前的一个研究课题.文中基于博弈论,对由防火墙、入侵检测系统和容忍入侵技术构成的三层安全体系结构进行了分析,提出了对信息安全技术进行评价的模型.在对入侵检测系统分析评价的基础上,重点分析了防火墙、入侵检测与容忍入侵的相互影响和关系.研究表明,IDS的检测率、误报率与防火墙的性能有密切关系,系统安全配置直接影响信息安全机制的性能和成本效益,容忍入侵机制取决于入侵的损失评估、系统的成本和防火墙与IDS的性能.信息安全机制的优化配置对于信息安全的效果具有重要影响.     

网络信息安全分析与防范策略

随着计算机信息技术的飞速发展,计算机网络已广泛用于经济、军事、教育等各个领域。计算机网络在带来海量信息的同时,由于网络的开放性和自由性也产生了私有信息和数据被破坏或侵犯的可能性,因此,网络信息的安全性变得日益重要起来。本文对目前计算机网络存在的安全隐患进行了分析,并探讨了针对计算机安全隐患的防范策略。     

计算机网络信息安全与防范

随着计算机信息技术的飞速发展,计算机网络已广泛用于经济、军事、教育等各个领域。计算机网络在带来海量信息的同时,由于网络的开放性和自由性也产生了私有信息和数据被破坏或侵犯的可能性。因此,网络信息的安全性变得日益重要起来。对目前计算机网络存在的安全隐患进行了分析,并探讨了针对计算机安全隐患的防范策略。     

浅议移动Ad-hoc网络路由协议中的安全性问题

移动Ad-hoc网络是一种新颖的无线对等网络,随着无线终端设备(便携式电脑、PDA等)的日益普及,Ad-hoc网络在军事、商业、个人区域网络(PAN)及分布式Ubiquitous计算环境下均有非常广泛的应用前景。路由协议的安全性问题是Ad-hoc网络成为实用性技术前必须妥善解决的关键问题之一。文章提出了一种新的基于网络安全环境的Ad-hoc网络分类方法,并以此为基础制定了强制协作式安全和激励式安全两类基本安全策略,建议Ad-hoc网络中的路由安全机制应该根据安全环境的分类采用相应的安全策略进行设计,而不是人为假设安全机制的前提条件。     

Application Level Fault Tolerance in Heterogeneous Networks of Workstations

We have explored methods for checkpointing and restarting processes within the distributed object migration environment (Dome), a C++ library of data parallel objects that are automatically distributed over heterogeneous networks of workstations (NOWs). System level checkpointing methods, although transparent to the user, were rejected because they lack support for heterogeneity. We have implemented application level checkpointing which places the checkpoint and restart mechanisms within Dome's C++ objects. Application level checkpointing has been implemented with a library-based technique for the programmer and a more transparent preprocessor-based technique. Dome's implementation of checkpointing successfully checkpoints and restarts processes on different numbers of machines and different architectures. Results from executing Dome programs across a NOW with realistic failure rates have been experimentally determined and are compared with theoretical results. The overhead of checkpointing is found to be low, while providing substantial decreases in expected runtime on realistic systems.     

Queueing Networks with Dynamic Routing and Dynamic Stochastic Bypass of Nodes

We consider open exponential networks with routing matrices that depend on a network state. A customer entering a node is either independently of other customers queued with probability that depends on the network state or instantly bypasses the node with complementary probability. After bypassing a node, customers are routed according to a stochastic matrix that depends on the network state and may differ from the routing matrix. Under certain restrictions on parameters of the model, we establish a sufficient ergodicity condition and find the final stationary distribution.     

探析计算机网络的信息安全防护

网络发展至今,早已想到超出了人们当时的想象,计算机网络的应用范围也已经延伸到了国计民生的各个领域,并且还呈现不断扩大的趋势.特别是在金融领域的应用已经越来越深入,而凸显出来的信息安全问题也日渐严重.本文针对这一问题做了详细的分析探讨.