卫星网络路由技术

由于卫星网络路由技术应用环境的特殊性,研究人员不能根据实际的网络学习环境,只有通过模拟,和仿真工具NS2是指网络仿真设备版本2,NS(网络模拟设备)是开放源码软件仿真平台,与它对网络技术发展研究的科研人员,NS2已包含卫星节点,作为卫星链路模块但这些模块相对比较简单,只有单一层卫星网络.因此,本文提出了多个卫星网络在NS2仿真,实现层间通信网络路由协议多个卫星的研究和开发方法.     

无线自组织网络路由技术研究

通过对比分析不同类别的路由协议,总结出各个类别的适应性;通过NS2仿真情况证明,主动路由协议在节点静止情况下传输更快捷稳定;而按需路由协议在节点移动情况下能快速建立路由。     

Ad hoc网络两种按需路由协议性能分析

Ad hoc网络是一种无需依赖于事先布设的基础设施,而仅依靠网络内部节点之间的协作,就能够完成节点间通信的网络。比较了Ad hoc网络两种主流的按需路由协议：动态源路由协议,自组网按需距离矢量路由协议。使用基于ns-2的仿真模型进行仿真,并通过分组交付率、平均端到端时延、标准化路由负荷、对两种按需路由协议进行评估。实验结果表明即使DSR和AODV协议都是按需路由协议,但它们采取的路由机制的不同,导致它们的性能表现的巨大差异。     

MANET中路由算法对通信流自相似特性的影响

着重分析无线多跳移动网络中,不同路由算法对多媒体通信流自相似特性的影响.通过NS2仿真产生基于不同路由算法的通信流数据,运用V-T法和R/S图法分别分析其突发性参数.结果表明,基于表驱动的DSDV自相似参数最大,而分簇路由算法CBRP自相似参数最小,更有利于实时流媒体的传输.研究对提高无线网络路由协议的性能和多媒体服务的质量具有重要意义.     

基于NS2的智能集装箱网络路由协议的研究简

由于传统集装箱是由金属制造的,所以集装箱的箱与箱之间的信号屏蔽作用特别明显,以至于位于箱堆内侧的集装箱信息无法得到有效采集。严重影响了智能集装箱的实时监控操作。针对这种问题,文中结合了现实集装箱堆场管理的需求。提出了一种可行的智能集装箱网络路由协议CNRP（Container Network Routing Protocols）,并利用NS2网络仿真软件．进行了该协议与典型的网络路由协议AODV、DSR、DSDV的性能比较,实验结果表明该路由协议具有低能耗、短时延的特点。更加适合于3D—Mesh集装箱网络。     

选播路由仿真扩展在NS2中的实现

在分析网络仿真工具NS2的基础上,提出了选播路由模型及其组的管理,通过修改原有的数据结构和节点等的扩展技术,增加了选播路由模块以实现选播服务网络的仿真。通过仿真实验测试,扩展的路由模块有效地支持了选播的路由,实验结果表明,基于NS2的选播路由的功能扩展是可行、有效的。     

Ad Hoc网络路由协议研究及其性能比较

介绍和分析了当前Ad Hoc网络中的主要路由协议算法,在Linux下使用网络仿真软件NS2评价Ad Hoc路由协议中的距离矢量路由协议、临时排序路由算法、动态源路由协议和Ad Hoc按需距离矢量路由协议,编写了用于仿真实现的脚本程序,并对仿真结果进行了分析比较和性能评价,由此得出不同协议的特性及其适用范围。     

无线自组织网络路由协议的教学探索

本文借助NS2和NSG2软件,搭建了辅助无线自组织网络路由协议教学的平台,研究DSDV、DSR和AODV路由协议。本文通过NSG2软件生成TCL脚本文件,供NS2仿真使用,并生成nam文件和trace文件。nam文件可以演示路由协议的动态运行过程,trace文件可以分析路由协议的效果。这有利于学生掌握和理解"无线网络技术"课程中路由协议中的概念,提高教学质量和效果。     

Ad hoc网络按需路由协议的研究

Ad hoc网络是一种能随时随地组成网络而不需要任何固定的底层设备支持的自组网,因而得到越来越广泛的应用。Ad hoc网络通常的应用领域包括灾难等突发性事件的恢复、人群控制、寻找和援救等,也用于战场上的相互联络。文章主要针对按需式路由协议中流行的一种Ad hoc按需平面距离矢量路由协议（AODV）进行研究,利用NS2仿真平台对AODV路由协议进行了仿真,全面分析了AODV路由协议的性能。     

面向水下路由协议的通用验证方法

文章重点研究了一种面向水下路由协议的通用验证方法。从区域拓扑、节点能力、最优节点选择和路径生成等方面建立了模型;并以AODV协议为例进行了仿真验证,仿真结果表明文中设计的通用验证方法能够模拟该协议在预想场景下的使用效果和适用范围,能够为验证水下路由协议提供客观真实地依据。     

An overview of routing optimization for internet traffic engineering

Traffic engineering is an important mechanism for Internet network providers seeking to optimize network performance and traffic delivery. Routing optimization plays a key role in traffic engineering, finding efficient routes so as to achieve the desired network performance. In this survey we review Internet traffic engineering from the perspective of routing optimization. A taxonomy of routing algorithms in the literature is provided, dating from the advent of the TE concept in the late 1990s. We classify the algorithms into multiple dimensions: unicast/multicast, intra-/inter- domain, IP-/MPLS-based and offline/online TE schemes. In addition, we investigate some important traffic engineering issues, including robustness, TE interactions, and interoperability with overlay selfish routing. In addition to a review of existing solutions, we also point out some challenges in TE operation and important issues that are worthy of investigation in future research activities.     

Multihour engineering and traffic routing optimization in hierarchical telephone networks

Classical hierarchical routing in telephone networks is extended to a wider class called out-of-chain routing in such a way that some useful properties of hierarchical routing are retained. This new routing pattern offers more potential paths than the fixed hierarchical one and can be introduced as a dynamic routing where the fixed alternate sequences change at some predetermined instants during the day. The effect of this new routing pattern on the network performances is examined. The main topic of this paper is to present heuristic methods used to optimise such routings in large networks. We show on artificial networks that the throughput of a given network can be significantly improved by suitable routing choices. We demonstrate that the integration of routing changes within a multihour dimensioning process is possible but the lack of realistic data does not permit at this time to quantify the value of routing optimization on real networks.     

A solving method for singly routing traffic demand in telecommunication networks

The problem of assigning single paths to point to point demands in a network arises in the telecommunications industry. The well known atm technology involves such a problem when each demand must be assigned to a single virtual channel in an atm backbone network. This problem is referred to as the Bandwidth Packing Problem. For a given network and a set of point to point demands with related bandwidth requirement and profit, the problem consists in determining the most rewarding subset of demands for which all demands are single path routed according to the link capacity constraints. We propose a heuristic derived from an exact method to solve this problem. We use cutting planes to strengthen a path-based linear relaxation embedded in a Branch&Cut scheme. The results particularly depend on the ratio of the average edge capacity to the average bandwidth required by the demands. The method provides optimum or nearly optimum solutions for practical telecommunications problems within small computational time.     

城市道路交叉口信号配时多目标优化方法研究

针对目前交叉口信号配时优化目标单一、综合运行效率不高的问题,提出一种交叉口信号配时多目标优化方法。考虑绿灯时间、周期长度和饱和度等约束条件,通过加权系数法定义代价函数,使交叉口的延误时间、停车次数和通行能力在某种程度上达到最优。基于免疫克隆算法在处理多目标问题中具有最优解分布宽广性、均匀性好等特点,引入环境变异算子,提出环境变异免疫克隆算法对模型求解,增强了算法的全局搜索能力,提高了解的质量。仿真结果表明,与传统配时方法和改进粒子群算法相比,该文方法能有效减少信号交叉口的延误时间和停车次数,提高交叉口的运行效率。     

An improved method for a redundancy optimization problem

The present note suggests an improvement over an earlier method for a redundancy optimization problem. There is a drastic reduction in the number of steps required to arrive at the optimal allocation. A numerical example illustrates the technique.     

一种车载中控计算机的设计

全面介绍一种车载平台的中心控制计算机的设计与实现,基于其中心控制与管理的功能需求和车载平台严酷使用环境的可靠性要求,首先论述整机电气和结构的架构设计,然后详细阐述单机内部主要电路板卡如嵌入式CPCI计算机板、KVM切换板、千兆网络交换板、多串口扩展板的电气设计要点,最后提出单机结构加固及减振散热措施。该中心控制计算处理能力强、操作便捷、接口众多、可靠性高,对同类车载平台中心控制计算机的设计具有很强的参考意义。     

FGWSO‐TAR: Fractional glowworm swarm optimization for traffic aware routing in urban VANET

In mobile distributed applications, such as traffic alert dissemination, dynamic route planning, file sharing, and so on, vehicular ad hoc network (VANET) has emerged as a feasible solution in recent years. However, the performance of the VANET depends on the routing protocol in accord with the delay and throughput requirements. Many of the routing protocols have been extensively studied in the literature. Although there are exemptions, they escalate research challenges in traffic aware routing (TAR) protocol of VANET. This paper introduces the fractional glowworm swarm optimization (FGWSO) for the TAR protocol of VANET in an urban scenario that can identify the optimal path for the vehicle with less traffic density and delay time. The proposed FGWSO searches the optimal routing path based on the fitness function formulated in this paper. Fractional glowworm swarm optimization is the combination of the GWSO and fractional theory. Moreover, exponential weighted moving average is utilized to predict the traffic density and the speed of the vehicle, which is utilized as the major constraints in the fitness function of the optimization algorithm to find the optimal traffic aware path. Simulation of FGWSO shows the significant improvement with a minimal end‐to‐end delay of 6.6395 seconds and distance of 17.3962 m, respectively, in comparison with the other existing routing approaches. The simulation also validates the optimality of the proposed TAR protocol.     

基于嵌入式车载安全预警系统设计

针对当前驾驶安全备受关注的现状,基于ARM Cortex-M3内核的STM32设计了一种车载安全预警系统,该系统是实现对车辆超速监测、司机超劳监测、车辆定位、蓝牙免提和无线通信功能于一体的车载终端.详述了系统实现各功能模块的硬件设计方案,以及在软件方面如何移植μC/OS-Ⅱ实时操作系统,并完成各应用任务的调度和外围设备管理.     

An improved distance‐based ant colony optimization routing for vehicular ad hoc networks

Vehicular ad hoc network (VANET) has earned tremendous attraction in the recent period due to its usage in a wireless intelligent transportation system. VANET is a unique form of mobile ad hoc network (MANET). Routing issues such as high mobility of nodes, frequent path breaks, the blind broadcasting of messages, and bandwidth constraints in VANET increase communication cost, frequent path failure, and overhead and decrease efficiency in routing, and shortest path in routing provides solutions to overcome all these problems. Finding the shortest path between source and destination in the VANET road scenario is a challenging task. Long path increases network overhead, communication cost, and frequent path failure and decreases routing efficiency. To increase efficiency in routing a novel, improved distance‐based ant colony optimization routing (IDBACOR) is proposed. The proposed IDBACOR determines intervehicular distance, and it is triggered by modified ant colony optimization (modified ACO). The modified ACO method is a metaheuristic approach, motivated by the natural behavior of ants. The simulation result indicates that the overall performance of our proposed scheme is better than ant colony optimization (ACO), opposition‐based ant colony optimization (OACO), and greedy routing with ant colony optimization (GRACO) in terms of throughput, average communication cost, average propagation delay, average routing overhead, and average packet delivery ratio.