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张治国 《智能建筑电气技术》2007,1(5):64-67
1引言随着社会的进步,视频监控系统正在向全数字化时代发展。视频从前端图像采集设备输出时即为数字信号,并以网络为传输媒介,基于国际通用的TCP/IP 相似文献
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Ning Liu Dengming Zhu Zhaoqi Wang Hong Qin Jianfeng Zhan Jinzhu Gao 《Computer Animation and Virtual Worlds》2016,27(3-4):385-393
Because of intensive inter‐node communications, image compositing has always been a bottleneck in parallel visualization systems. In a heterogeneous networking environment, the variation of link bandwidth and latency adds more uncertainty to the system performance. In this paper, we present a pipelining image compositing algorithm in heterogeneous networking environments, which is able to rearrange the direction of data flow of a compositing pipeline under strict ordering constraint. We introduce a novel directional image compositing operator that specifies not only the color and α channels of the output but also the direction of data flow when performing compositing. Based on this new operator, we thoroughly study the properties of image compositing pipelines in heterogeneous environments. We develop an optimization algorithm that could find the optimal pipeline from an exponentially large searching space in polynomial time. We conducted a comprehensive evaluation on the ns‐3 network simulator. Experimental results demonstrate the efficiency of our method. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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本文的主要针对基于ZigBee的温室大棚环境监控硬件系统需求,构建无线传感器网络的节点端、中间件和客户端,使用Lab VIEW平台开发监控系统客户端界面,在Mote Works中开发一些自组网技术的节点端,负责对传感器采集的到的一些数据进行存储转发,而中间件是由Xserve去实现并对组建的模拟系统进行测试。 相似文献
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“内容中心网络”(Content Centric Networking,CCN)是未来互联网架构体系群中极具前景的架构之一。CCN的核心思想在于内容命名,即用户不需要根据数据的地址而仅根据数据的名字来获取目标内容。在设计上,CCN是一种基于拉(pull-based)的网络,即用户为了获取相应的内容,必须向网络发送一个兴趣包(Interest)以便获取同名数据包(Data),也就是说CCN是一个用户驱动的网络。安全对任何一种网络架构来说,都是不容忽视的一个问题,其中,拒绝服务攻击(DoS)是TCP/IP网络中最为常见的攻击手法之一,这里研究了CCN中常见的DoS攻击,并提出了具有针对性的解决方案。 相似文献
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The past years have witnessed a significant increase in the number of WLANs deployed in most of the enterprises, campuses and public areas to provide high-speed Internet connectivity. These WLANs typically consist of APs densely installed to assure enough capacity to meet users demand during the peak period of activity. At the same time, it translates into a serious energy wastage during low-utilization periods, when capacity is not needed at the APs. To reduce this wastage, many proposed solutions consist of adapting the active capacity to the actual needs, introducing switching strategies able to turn on and off the APs. The effectiveness and potential benefit of these strategies strongly depend on the user behavior and traffic patterns.In this paper, we focus our analysis on the real usage characteristics of a dense WLAN (such as users’ behavior and users’ mobility patterns) in a university campus and evaluate potential energy savings and benefits achievable when introducing AP on/off switching strategies. We discuss different strategies, in which decisions are based either on: (1) historical behavior in the campus, or on (2) current AP utilization. In addition, considering the large overlapping coverage available in dense WLANs, we investigate users’ mobility patterns to derive further improvements to AP switching strategies. The results show that, due to the repetitiveness of users’ patterns and large differences in WLAN usage between days and nights, as well as between weekdays and weekends, large savings of up to 40% can be easily achieved. Moreover, by fine-tuning the strategies in different areas of the campus, additional savings are possible. The deployment of these strategies leads to energy saving and, as a practical consequence, to a remarkable reduction of electricity costs. 相似文献