体系对抗仿真中的信息网络建模研究与实现

信息化条件下战争系统以体系对抗为特征.为了研究信息网络在战争系统中的作用原理和运行机制,针对信息化条件下的体系对抗仿真系统开发,以体系对抗仿真模型体系为基础,以仿真信息化战争系统所具有的整体性、对抗性、动态性特征为需求,提出建立信息网络模型的研究思路,并依据系统工程的方法步骤,按照需求分析、概念建模、仿真建模、模型验证和仿真运行与收集仿真结果的步骤对典型作战体系--防空反导体系的网络模型研究与实现的过程进行了系统的探讨.     

末敏弹仿真系统的UML建模研究

构建末敏弹仿真系统已成为研究末敏弹运动规律和效能评估的重要手段.采用统一建模语言(UML)对系统用例模型、实体结构模型及行为模型等进行了可视化建模:该研究在较大程度上解决了从需求分析到软件开发全过程的末敏弹仿真系统的建模问题,为高效、高质量的末敏弹仿真奠定基础.     

应用Repast S的复杂系统建模仿真

研究社会灾害和生态环境中的发慌问题,需科学决策.针对复杂系统的研究涉及到多种学科交叉,进行多Agent建模仿真需要面对不同领域知识融合的问题.在最新多Agent建模仿真平台Repast Simphony(简称Repast S)的研究基础上,为决策者提供依据,提出以其层次建模框架满足多专家群体协作建模需求,以Score元模型为建模基础进行领域知识融合的策略.以森林火灾系统为例,应用Repast S进行了建模仿真实践.所建立模型有机融合了林火蔓延的元胞自动机模式和扑救协作的社会网络模式等领域知识,进行仿真.仿真结果体现出各种模式对森林火灾系统演化态势的影响.Repast S为复杂系统学科交叉的多Agent建模仿真提供了有效支持.     

RBF-ARX模型在液位系统建模中的应用

针对单容液位系统紊流时的非线性特征,采用RBF-ARX模型对单容液位系统进行离线动态特性建模的研究;分别在液位高中低三个工作点建立了其局部线性ARX模型,它们的单位阶跃响应存在巨大差异,证实了整个系统具有较强的非线性;讨论了RBF-ARX模型结构的选取,模型参数辨识,RBF参数优化等问题;模型的预测输出和仿真结果,证实了RBF-ARX模型在非线性系统建模和辨识中的有效性.     

关于仿真模型检验的研究

仿真系统的可信性,它关系到系统的研制周期、使用寿命和可靠性。建模仿真可信性研究,又称为建模仿真“校核、验证和确认”,就是解决模型有用、敢用和相信问题,这是非常重要的。建模仿真VV＆A研究包括概念性研究、建模仿真VV＆A过程、VV＆A技术方法等。事实上,建模仿真VV＆A是建模仿真的全面质量管理,包含技术和管理工作。该文通过借鉴国内外在该领域的研究成果,对建模仿真VV＆A理论进行了概述研究,并给出建模仿真方法。     

超宽带室内修正S—V信道模型的仿真与分析

信道模型是无线通信系统研究和设计的基础.介绍了超宽带室内无线通信信道模型,给出了泊松过程模型、△-K模型、S-V模型以及IEEE802.15.3a模型等典型UWB信道模型的建模方法和特征,针对室内信道多径分量的成簇到达特性提出了修正的S-V信道模型并对其进行仿真.仿真结果表明,该模型能较好的反应UWB信道的特征参数.     

行人运动建模及仿真研究综述

根据行人运动建模及仿真发展历史以及已经提出的一些模型和算法,从宏观和微观两个层面对行人运动建模策略进行系统分析,包括宏观建模策略:行人动力学模型、空间交互/熵最大化模型以及微观建模策略:元胞自动机模型、磁力场模型、社会力模型、智能体模型、空间句法模型、马尔可夫模型.在建模策略分析基础上,重点研究了Legion,PAXPORT,NOMAD,STEPS以及BuildingEXODUS五种主流行人仿真系统,总结了各系统的建模思想、核心模型及优缺点.指出了未来行人系统建模及仿真的研究趋势.     

基于Agent的战争舆情演化模型研究

基于仿真实验研究战争舆情演化规律是战争复杂系统建模与仿真要解决的新问题.针对战争舆情演化仿真的需求,在界定舆论、舆论战、战争舆情的概念和分析影响战争舆情变化主要因素的基础上,提出了采用基于Agent的建模方法构建战争舆情演化模型的思路,探讨了基于Agent的战争舆情演化模型结构,研究了有关模型设计与实验的前端、内核、输出等问题.建立了模型原型,进行了有关的仿真实验.仿真实验结果表明,基于Agent的战争舆情演化仿真具有可信性和可用性.     

基于Modelica的泵车臂架系统多领域耦合动力学建模与仿真

主要介绍一种基于 Modelica 语言的泵车臂架系统多领域耦合动力学仿真建模方法. 泵车臂架系统是典型的机械、液压、控制等多领域耦合系统,在其频繁的启动、制动过程中,变幅机构和液压元件均承受着强烈的冲击和振动. 传统的单一领域动力学建模方法很难全面反映泵车臂架系统的整体动力学性能,然而通过几种仿真工具进行联合仿真的方法亦难免存在建模效率、仿真速度等方面的问题. 针对以上不足,以某型泵车为研究对象,提供一种基于多领域统一建模语言 Modelica 的机械、液压及控制等多场耦合的泵车臂架系统动力学建模方法,并对其工作过程进行了动态仿真. 该模型具有模块化、层次化、规范化和参数化,以及仿真模型互操作性和重用性强的特点.     

多输入–多输出非线性系统的特征模型及在挠性卫星姿态控制中的应用

研究多输入–多输出（MIMO）高阶非仿射非线性系统的特征建模问题.首先证明了MIMO高阶非仿射非线性系统的特征模型可用二阶时变差分方程组描述,并给出了特征模型的建模误差.然后设计了基于特征模型的自适应模糊广义预测控制器,利用Lyapunov方法分析了闭环系统的稳定性.由于控制结构中使用了分层模糊逻辑系统,从而极大减少了模糊规则和可调参数的个数,提高了控制的实时性.通过对挠性卫星姿态控制的仿真研究验证了所给控制方案的有效性,可实现高精度的姿态控制,且该方法具有较强的鲁棒性.     

基于OPNET的IEEE802．11信道接入技术仿真研究

信道接入控制技术是实现无线网络节点共享无线信道空间的关键技术。IEEE802．11作为无线局域网的一个重要协议标准,定义了两种信道接入控制方式,分别是分布式协调方式和中心协调方式。本文主要研究了以IEEE802．11协议标准为对象的无线局域网两种信道接入技术的学习和讨论,并运用先进的网络仿真工具OPNET对信道接入技术进行了仿真研究,总结了不同信道接入技术下的无线局域网的网络性能。指出设计网络时需要根据不同情况来选用不同的方式来进行通信。     

Underwater acoustic communication and the general performance evaluation criteria

Driven by the huge demand to explore oceans, underwater wireless communications have been rapidly developed in the past few decades. Due to the complex physical characteristics of water, acoustic wave is the only media available for underwater wireless communication at any distance. As a result, underwater acoustic communication (UAC) is the major research field in underwater wireless communication. In this paper, characteristics of underwater acoustic channels are first introduced and compared with terrestrial communication to demonstrate the difficulties in UAC research. To give a general impression of the UAC, current important research areas are mentioned. Furthermore, different principal modulation-based schemes for short- and medium-range communications with high data rates are investigated and summarized. To evaluate the performance of UAC systems in general, three criteria are presented based on the research publications and our years of experience in high-rate short- to medium-range communications. These three criteria provide useful tools to generally guide the design and evaluate the performance of underwater acoustic communication systems.     

无线通信技术的热点及发展趋向探析

随着经济的发展和社会的进步,特别是随着信息化时代的到来,人们对无线通信工具的应用已经达到了一个新的层次.从国内外的发展历程和现状看,无线通信领域在当前具有两个最突出的特点：一是无线通信的用户数量虽然在各个国家和地区呈现出不均衡的状态,但是总体上仍然保持着强劲的增长趋势;二是这一领域的技术热点层出不穷,在科学研究和应用中都保持了非常活跃的姿态.本文通过对当前几种热点技术的介绍进一步探析无线通信技术的发展趋向.     

Next Generation Wireless Security Tools

It happens every year. Summer security conventions bring computer professionals and hackers from around the world to a handful of venues. Premier among these gatherings are the BlackHat and DefCon, conventions held in late July under the hot sun of Las Vegas. And each year new security tools are released, old tools are given new life, and new vulnerabilities are announced. This year was no exception. The weeklong security fest saw dozens of new tools including a handful of wireless utilities. This new round of wireless security tools represents a new level of sophistication and danger in the wireless security arena.     

Innovative socio-technical environments in support of distributed intelligence and lifelong learning

Abstract   Individual, unaided human abilities are constrained. Media have helped us to transcend boundaries in thinking, working, learning and collaborating by supporting distributed intelligence . Wireless and mobile technologies provide new opportunities for creating novel socio-technical environments and thereby empowering humans, but not without potential pitfalls. We explore these opportunities and pitfalls from a lifelong-learning perspective and discuss how wireless and mobile technologies can influence and change conceptual frameworks such as the relationship between planning and situated action, context awareness, human attention, distances in collaborative design activities, and the trade-off between tools for living and tools for learning . The impact of wireless and mobile technologies is illustrated with our research projects, which focus on moving 'computing off the desktop' by 'going small, large, and everywhere'. Specific examples include human-centred public transportation systems, collaborative design, and information sharing with smart physical objects.     

基于NS2的无线地下传感器网络信道模型的扩展与实现

 无线地下传感器网络作为一个全新的研究领域,它的大多数研究还在理论阶段。建立一个更接近真实地下环境的仿真平台,可以减少部署实验所耗费的资源。本文以现有的双径模型叠加多径瑞利衰落的地下信道模型为基础,建立考虑电磁传播信号所有成分的地下信道模型,同时增加地下-地上信道模型以及地上-地下信道模型,在NS2上进行仿真实现。在实现的平台上进行仿真,分析了吞吐率和丢包率这2个性能指标在不同通信距离的变化规律。仿真结果表明,所采用的模型能很好地反映地下通信情况,验证了模型用于地下环境仿真的可行性,为无线地下网络的学习和研究提供了参考及工具。     

Social networks as health feedback displays

Social networks have thus far served primarily as analytic tools for social scientists. By leveraging pervasive computing, this new research transforms social-network models into behavioral feedback displays. These ambient displays, which reflect data on remote and face-to-face interaction gathered by wireless sensor networks, were intended to raise awareness of social connectedness as a dynamic and controllable aspect of well being. An interdisciplinary health technology research group at Intel recently developed and tested prototypes in the homes of older adults and their caregivers. This article reviews the psychological rationale for the project and highlights some reactions of participants to the displays.     

Performance evaluation of wireless sensor network protocols for industrial applications

Recently, distributed wireless microsensor systems have provided more flexible leverage to emerging industrial applications. The tiny distributed wireless microsensor network systems, however, should be designed to overcome various constraints such as limited energy, bandwidth limit, and unexpected failure of communication under disturbances. In addition, their network topologies need to be managed with designated communication protocols. Thus, design of microsensor network protocols still needs to be application-specific. It should be also evaluated through designated tools at each level of networking characteristics. This research describes essential factors that affect the performance of sensor network systems in the design of wireless microsensor network protocols, and presents effective time-based network protocol and performance evaluation tool which are applicable for various protocols in industrial applications. The developed network evaluation tool, called TIE/MEMS, also includes functional comparison with recent protocols proposed for wireless microsensor networks, and provides design guidelines for multi-sensor network systems needed for emerging industrial applications.     

基于嵌入式Linux的Ad-Hoc网络视频传输研究

针对目前多数无线网络通信依赖于接入点(AP,access point)的现状,采用ARM9处理器(S3C2440)与嵌入式Linux操作系统相结合的技术,组建了Ad-Hoc无线网络通信系统.重点对无线网卡驱动程序进行了深入分析,实现了无线网卡在Linux环境下的移植,通过移植无线网络配置工具使无线网卡工作于Ad-Hoc...     

浅谈无线网络安全问题

无线网络以其"无所不在"的空间覆盖特性使其市场需求巨大、应用日益广泛,但随而其安全问题也越来越引起广大用户的普遍关注。本文通过对无线网络特点及应用进行介绍,分析、探讨了无线网络面临的安全问题及攻击工具,最后提出无线网络安全解决方案。