Redundant wireless communication technologies for real-time surveillance

Catastrophic events including those sparked by terrorism have cast a pall over society in recent years. Events such as September 11th or the bombing of the Alfred P. Murrah Federal Building in Okalahoma City demonstrated a sudden surge in telephone call volume. These events indicated that communications systems, including cellular, can fail as a result from damage or capacity overload. Cellular systems have significant capacity given the limited radio spectrum allocated but much like airlines that oversell seats because inevitably some passengers do not show up, cellular providers typically have more customers than operational spectrum can handle in aggregate. Normally this is perfectly acceptable because a high percentage of the customer base would never be making calls simultaneously; except in an emergency. Such emergencies can be active or passive in nature. The release of dangerous airborne agents is one such scenario. The purpose of this study was to use a portable air particulate sensor as a data acquisition platform to evaluate the capability of real-time data throughput using existing wireless topologies, Java, eXtensible Markup Language (XML) and Internet protocols when cellular transmission frequencies are compromised. Results show that high levels of cellular voice traffic in a given area can hamper simultaneous data communications; however, Low Earth Orbiting Satellites (LEOS) can provide redundancy.     

无线视频监控系统中的安全机制研究

无线视频监控系统的安全不能单纯依靠加密来保证,从信息系统安全体系的角度,对无线视频监控系统的安全进行了分析,并对系统中主要应用的鉴权、密钥管理、空中接口加密、端到端加密等安全机制进行了重点研究。     

基于ARM的嵌入式家用无线视频监控系统

介绍了一种基于ARM的室内无线视频系统设计方法,该系统的主要构成模块包括：主控模块、图像处理模块、无线传输模块三模块。该系统通过将删改过的linux内核以及文件系统移植到ARM芯片中来完成主控芯片对各硬件系统的支持。通过测试表明,该系统设计方案合理、有效能够较好的达到设计目的和要求。     

基于ARM技术的无线视频监控系统设计

随着嵌入式技术以及无线通信技术的发展,无线视频监控领域进入了一个崭新的发展时期。基于嵌入式技术的视频监控技术是一种先进技术,为视频监控设备的设计开发提供了一种全新解决方案。目前,采用无线网络技术的视频监控系统依靠其更低廉的价格、更加灵活的部署方式得到广大视频监控用户的青睐,逐渐成为视频监控技术的发展方向之一。在此结合嵌入式技术和无线视频监控技术,提出了一种基于嵌入式技术的无线智能视频监控系统解决方案。     

面向Android客户端的无线视频监控系统设计

为了满足智能家居应用中随时随地进行视频监控的要求,基于ARM嵌入式平台,设计一种面向Android客户端的无线视频监控系统,该系统可实现无线中继传输,具备端到端动态地址连接能力,并按需采集传输视频数据。系统采用H.264视频编码技术,基于实时传输协议和IEEE 802.11g协议传输数据,可通过无线局域网或互联网获得监控视频。通过构建实验演示平台进行了系统测试和分析,结果表明该系统部署灵活,获取的监控画面清晰稳定,可以满足无线网络环境下家庭视频监控的要求。     

校园无线视频监控系统的设计与应用

为解决校园内及周边视频监控点布置分散等原因造成的无法实现远程视频监控问题,针对3G无线网络的特点,描述了基于3G标准的无线视频监控系统关键技术的研究与实现方法。在数据传输中利用RTP协议中时间戳,解决音视频同步的问题,对监控系统的客户端与服务器端进行了设计。实际应用表明,该系统设计合理,可靠性好,能对校园内外目标实现有效监控。     

基于WIFI技术的无线视频监控系统研究

视频监控能够实时拍摄、存储画面,其应用十分广泛。但目前应用最广的是有线监控,其不仅造价昂贵而且摄像头一旦固定后很难移动,在高速公路、森林等地方有线监控受到了很大的限制。利用WIFI技术搭建无线局域网,通过无线局域网的传输能够实现无线视频监控,这一技术成本低、组网简单、功耗小、监控效果好,有值得推广的价值。     

无线传输移动视频监控系统设计探究

近年来,网络视频监控在各个领域得到了广泛的应用,通过网络监控系统应用,能够为大众提供更好的服务,同时还可以维护社会的稳定,促进我国社会经济的持续发展.本文阐述了网络视频监控系统设计构思,在此基础上,针对网络视频监控系统设计中相关要点及应用效果进行了分析,以供读者参考.     

基于CC1100的无线视频监控系统设计

为了对特定场合进行安全监控,采用CC1100无线传输模块和PTC08串口摄像头模块设计并实现了一种无线视频监控系统。利用摄像头模块对视频进行数据采集、压缩、串口传输,并利用微控制器通过无线传输模块进行拍摄控制、数据传输。经测试表明,该系统具有操作简便、运行稳定的特点,达到了设计要求。     

网络无线侦察接收机软件系统的设计和实现

为兼容无线电监测网传输协议(RMTP),实时监测无线电信号并测量其频率、带宽等技术参数,无线侦察接收机软件系统通过网络接收硬件采集的无线电信号,使用经典功率谱估计方法对其进行频谱分析.系统用户界面采用跨平台GUI库CodeBlocks+wxWidgets进行开发,使用二维图形库wxMathPlot开发画图模块,将测量和分析的结果以频谱图的方式展现给用户.分析了系统的基本架构,wxWidgets库的使用方法,经典功率谱估计算法,重点讨论了如何解决网络传输过程中可能遇到的"粘包"问题.     

Dynamic energy-efficient surveillance routing in uncertain group-based industrial wireless sensor networks

Wireless Networks - Smart factories in harsh large-scale environments are achieved by installation of group-based industrial wireless sensor networks (GIWSNs), in which a group of sensors are...     

基于ARM Linux的3G无线车载视频监控系统

为了加强客运服务中心对长途车辆在客运过程的监管,提出了基于ARMLinux的3G无线车载视频监控系统。该系统基于ARMLinux嵌入式系统与ARM处理器,通过USB摄像头采集车内视频数据,由GPS定位模块获取车辆的位置数据,然后将采集的数据经过H．264压缩成适合网络传输的形式。最终通过3G无线发射模块经过具有宽带传输能力的3G移动通信网络传输给监控服务中心,监控服务中心可以看到车内清晰流畅的视频画面以及车辆所在位置。     

Optimal barrier coverage for critical area surveillance using wireless sensor networks

Intrusion detection using barrier coverage is one of many applications existed in wireless sensor networks. The main purpose of using barrier coverage is to monitor the borders of a specific area against the intruders that are trying to penetrate this critical area by ensuring the total coverage with a low cost and extending the lifetime of the network, many solutions have been proposed in the literature in order to solve the coverage problem in wireless sensor networks, which became a vital field of research. In this paper, we present a new technique based on geometric mathematical models, in order to guarantee the total coverage of our deployed barriers with a minimum possible number of sensors. The idea is to calculate the number of sensors adequate to cover a barrier before deployment. We then formulate the problem to minimize the number of sensors to be deployed to properly cover a barrier; the calculation makes it possible to solve this problem in polynomial using our own heuristic. Additionally, we propose a new mechanism for ensuring a fault‐tolerant network by detecting the faulty sensors and select other suited sensors to close the existing gaps inside the barriers and detecting the sensors whose energy is low before the failure. The obtained simulation results prove the effectiveness of the proposed algorithms.     

Intelligent PV Module for Grid-Connected PV Systems

Most issues carried out about building integrated photovoltaic (PV) system performance show average losses of about 20%–25% in electricity production. The causes are varied, e.g., mismatching losses, partial shadows, variations in current–voltage$(I$–$V)$characteristics of PV modules due to manufacturing processes, differences in the orientations and inclinations of solar surfaces, and temperature effects. These losses can be decreased by means of suitable electronics. This paper presents the intelligent PV module concept, a low-cost high-efficiency dc–dc converter with maximum power point tracking (MPPT) functions, control, and power line communications (PLC). In addition, this paper analyses the alternatives for the architecture of grid-connected PV systems: centralized, string, and modular topologies. The proposed system, i.e., the intelligent PV module, fits within this last group. Its principles of operation, as well as the topology of boost dc–dc converter, are analyzed. Besides, a comparison of MPPT methods is performed, which shows the best results for the incremental conductance method. Regarding communications, PLC in every PV module and its feasibility for grid-connected PV plants are considered and analyzed in this paper. After developing an intelligent PV module (with dc–dc converter) prototype, its optimal performance has been experimentally confirmed by means of the PV system test platform. This paper describes this powerful tool especially designed to evaluate all kinds of PV systems.     

边海防视频监控系统无线组网模式应用研究

结合对边海防视频监控系统结构及各部分功能特征的深入分析,研究了多种典型的中心节点局域网无线组网方式,及其拓扑结构和优势特点,并针对不同实地环境下的边海防需求,分别提出了适用的视频监控系统无线组网模式。     

基于校园无线网的视频监控研究——以南宁学院为例

校园安全问题作为社会持续的一个热点话题,每次出现相关校园安全的新闻都会迅速受到社会各界的广泛关注,校园内十分有必要搭建高效可靠的安防体系来维护师生学习环境的安全.视频监控网络是安防体系的重要一环,是一种能够有效提高校园安全保障的有力措施.