基于NS-2的无线网络仿真分析与研究

网络仿真是研究网络性能和网络设计的重要工具。文中首先介绍了网络仿真工具NS-2的原理及网络仿真步骤,然后用Otcl脚本语言构建一个虚拟的无线网络环境,同时详细描述了无线网络的仿真过程,最后用gawk工具对Trace文件的数据进行分析。     

基于NS-2的无线网络仿真分析与研究

网络仿真是研究网络性能和网络设计的重要工具。文中首先介绍了网络仿真工具NS-2的原理及网络仿真步骤．然后用Otcl脚本语言构建一个虚拟的无线网络环境,同时详细描述了无线网络的仿真过程,最后用gawk工具对Trace文件的数据进行分析。     

NS-2的仿真模拟技术分析

网络仿真是研究通信网络技术的有效工具。仿真模拟功能提供了实际网络和仿真器交互的能力。该文介绍了NS-2的结构及网络仿真的设计流程,重点分析了网络仿真NS-2中仿真模拟功能的设计和实现。     

基于NS—2软件的网络仿真设计与分析

网络仿真技术已成为研究网络性能、设计网络方案所不可缺少的工具。NS-2是一个面向对象的离散事件驱动的仿真软件,文中介绍了它的体系结构、仿真设计方法,并用多播通信的仿真实例,体现了它在网络的分析、设计和优化等方面的作用。     

网络仿真及OPNET应用研究

网络仿真技术是进行网络规划与设计的有效方法和工具。本文在系统地分析网络仿真基本方法和仿真流程的基础上,阐述了网络仿真平台OPNET的主要特性、建模机制及其仿真方法和步骤。基于OPNET对一个点对点的无线网络模型进行仿真,给出仿真结果并对其进行了分析。     

网络仿真技术与OPNET应用实践

网络仿真技术是研究人员在进行网络规划与设计时必要的、有效的工具。本文首先简要介绍了几种常用的网络仿真软件,接着重点分析了网络仿真软件OPNET的主要特点、三层建模机制以及OPNET的仿真方法和步骤, 最后通过一个实例来讨论了OPNET技术在具体网络规划和设计中的应用。     

基于Matlab环境的网络控制系统仿真平台

网络控制系统NCS(NetworkedControlSystem)是一种分布式实时控制系统,网络控制系统的设计与研究涉及系统控制与网络调度两个方面,目前集成的控制与调度仿真工具很少。该文对网络控制系统的仿真平台进行了分析,给出了Matlab构建的网络控制系统框架,分析了网络控制系统仿真模型,介绍了一种基于Matlab的网络控制系统的理想仿真工具TrueTime。     

网络仿真在教学中的应用研究

网络仿真技术是一种通过建立网络设备、链路和协议模型,并模拟网络流量的传输,从而获取网络设计或优化所需要的网络性能数据的仿真技术。该文使用主流网络仿真工具NS2对教学实验网络建立了仿真模型,讨论了网络拓扑结构和仿真参数的选取方法。仿真结果表明丢包率随着网络数目的增加显著提高。     

网络仿真在教学中的应用研究

网络仿真技术是一种通过建立网络设备、链路和协议模型,并模拟网络流量的传输,从而获取网络设计或优化所需要的网络性能数据的仿真技术。该文使用主流网络仿真工具NS2对教学实验网络建立了仿真模型．讨论了网络拓扑结构和仿真参数的选取方法。仿真结果表明丢包率随着网络数目的增加显著提高。     

模拟仿真网络到真实网络的接口的研究和实现

网络仿真软件已成为研究、规划、设计网络不可缺少的工具。文章主要讨论了仿真网络与真实网络接口模块的原理,并应用NAT和代理服务器技术对其进行了开发实现。经在NetSim仿真软件上验证,其实现了软件层次上的透明代理,扩展了仿真软件的应用范围。     

基于OPNET的流媒体传输性能仿真比较研究

网络仿真为网络规划设计和网络性能分析提供客观、可靠的定量依据,大大缩短网络的建设周期和新协议开发周期,本文利用OPNET网络仿真工具,对四种常用的队列算法FIFO、CQ、PQ、WFQ进行仿真,分析比较它们对时延的不同影响和提供不同的QOS服务。     

Performance evaluation of network processor architectures: combining simulation with analytical estimation

The designs of most systems-on-a-chip (SoC) architectures rely on simulation as a means for performance estimation. Such designs usually start with a parameterizable template architecture, and the design space exploration is restricted to identifying the suitable parameters for all the architectural components. However, in the case of heterogeneous SoC architectures such as network processors the design space exploration also involves a combinatorial aspect––which architectural components are to be chosen, how should they be interconnected, task mapping decisions––thereby increasing the design space. Moreover, in the case of network processor architectures there is also an associated uncertainty in terms of the application scenario and the traffic it will be required to process. As a result, simulation is no longer a feasible option for evaluating such architectures in any automated or semi-automated design space exploration process due to the high simulation times involved. To address this problem, in this paper we hypothesize that the design space exploration for network processors should be separated into multiple stages, each having a different level of abstraction. Further, it would be appropriate to use analytical evaluation frameworks during the initial stages and resort to simulation techniques only when a relatively small set of potential architectures is identified. None of the known performance evaluation methods for network processors have been positioned from this perspective.We show that there are already suitable analytical models for network processor performance evaluation which may be used to support our hypothesis. To this end, we choose a reference system-level model of a network processor architecture and compare its performance evaluation results derived using a known analytical model [Thiele et al., Design space exploration of network processor architectures, in: Proc. 1st Workshop on Network Processors, Cambridge, MA, February 2002; Thiele et al., A framework for evaluating design tradeoffs in packet processing architectures, in: Proc. 39th Design Automation Conference (DAC), New Orleans, USA, ACM Press, 2002] with the results derived by detailed simulation. Based on this comparison, we propose a scheme for the design space exploration of network processor architectures where both analytical performance evaluation techniques and simulation techniques have unique roles to play.     

利用MATLAB进行船舶舵鳍联合减摇智能控制系统设计与仿真

该文针对象船舶舵鳍联合减摇系统这样的复杂模型的仿真以及智能控制系统设计中需训练控制器、仿真中的变参数控制等特点,介绍了一种用SIMULINK对变参数顺系统进行仿真的方法,给出了利用MATLAB环境设计如神经网络控制器等智能控制器的方案,最后给出了所述设计方案和仿真方法的具有实例：利用遗传算法训练模糊神经网络控制器对船舶舵鳍联合减摇系统进行控制。     

基于OPNET的FTP流量模型仿真研究

网络仿真是一种全新的网络规划、设计和分析技术,它能够验证实际方案的有效性和比较多个不同的设计方案,为网络的规划设计提供可靠的定量依据。针对网络仿真中的关键问题——流量仿真与建模,介绍了软件仿真系统OPNET的流量仿真与建模机制,并就网络仿真中FTP业务前景流量数学模型的建立做了研究,最后基于OPNET融hnology公司开发的网络仿真软件OPNET平台对仿真模型进行了仿真验证。     

OPNET网络仿真技术及其应用分析

网络仿真技术是一种研究网络规划与设计的有效工具。仿真软件提供了真实网络和仿真器交互的方法,它通过不同条件下对网络的模拟来分析设计方案的可行性和健壮性。介绍了网络仿真技术OPNET的组成和特点,讨论了OPNET的仿真流程,并结合实例通过描述延迟和负载的变化来着重分析了OPNET在具体网络规划中的应用。     

OPNET网络仿真技术及其应用

网络仿真技术是一种研究网络规划与设计的有效工具。仿真软件提供了真实网络和仿真器交互的方法,它通过不同条件下对网络的模拟来分析设计方案的可行性和健壮性。介绍了OPNET网络仿真软件,并对其主要特性、建模机制以及仿真步骤进行了深入的阐述,并结合实例通过描述延迟和负载的变化来着重分析了OPNET在具体网络规划中的应用。     

Hybrid simulation-analytical modeling approaches for the reverse logistics network design of a third-party logistics provider

In this study, we consider a manufacturer that has strategically decided to outsource the company specific reverse logistics (RL) activities to a third-party logistics (3PL) service provider. Given the locations of the collection centers and reprocessing facilities, the RL network design of the 3PL involves finding the number and places of the test centers under supply uncertainty associated with the quantity of the returns. Hybrid simulation-analytical modeling, which iteratively uses mixed integer programming models and simulation, is a suitable framework for handling the uncertainties in the stochastic RL network design problem. We present two hybrid simulation-analytical modeling approaches for the RL network design of the 3PL. The first one is an adaptation of a problem-specific approach proposed in the literature for the design of a distribution network design of a 3PL. The second one involves the development of a generic approach based on a recently proposed novel solution methodology. In the generic approach instead of exchanging problem-specific parameters between the analytical and simulation model, the interaction is governed by reflecting the impact of uncertainty obtained via simulation to the objective function of the analytical model. The results obtained from the two approaches under different scenario and parameter settings are discussed.     

JTIDS网络建模与仿真平台设计

基于对JTIDS网络的研究,建立了符合OSI分层标准的端机模型和毁伤加载节点模型,仿真平台实现了基本网络功能,并重点解决了功能端机退出带来的网络拓朴结构变化问题和链路仿真和网络仿真跨平台间的接口问题.针对不同设置,仿真实验将获得各种情况下的网络和端机性能指标,有效地指导了网络设计和优化.     

Demand-driven logic simulation using a network of loosely coupled processors

Logic simulation is used extensively in the design of digital systems for the purpose of studying the behaviour of circuits under various conditions and for verifying the required performance of circuits. There is considerable interest in methods which reduce the simulation time during the design process. In this paper, we investigate how this can be achieved by simulating the action of logic circuits using a network of loosely coupled processors. Circuits modelled as directed graphs comprising clocked sequential components and (unclocked) arbitrary combinational logic gates can be partitioned into separate tasks each consisting of a sequential component with an associated network of combinational components. We present cost functions for evaluating a task subject to probabilistic assumptions about the functioning of the circuits. The circuit evaluation method used in the simulation process is significant. We apply lazy evaluation, a demand-driven evaluation strategy in which signals in the circuit are evaluated on a ‘need to do' basis, resulting in a considerable saving in circuit simulation time. We achieve distributed logic simulation using a network of workstations and show from experimental results that by using such a configuration, we essentially obtain a single computation engine which can be used to obtain speedups in circuit simulation when compared with uniprocessor simulation systems. Interprocess communications between tasks on different workstations proceed via remote procedure calls while local communications between tasks take place via shared memory. The method of partitioning used in the circuit model ensures that communications between tasks take place only at defined times in the simulation sequence.     

基于OPNET的计算机网络仿真实践教学研究

针对目前计算机网络课程教学存在的问题,提出在网络实验中引入网络仿真技术的教学方法。阐述OPNET网络仿真技术在实验教学中的作用,在此基础上把仿真实验划分为验证性实验、设计型实验、综合型3种。最后以一个设计型仿真实验说明网络仿真技术在提高实验教学水平和质量方面的有效性。