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戴刚 《无线电技术(上海)》2009,(1):1-10
本文介绍卫星上常用的CAN总线在多主情况下的通讯策略,给出实际使用的电路原理图、主要程序流程图以及注意事项。从CAN总线控制芯片SJA1000的底层分析发送缓冲区、接收缓冲区、内部指令和中断信号等之间的关系,以及在多主情况下冲突处理机制。 相似文献
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一种基于标准CMOS工艺的低成本振荡器的设计 总被引:1,自引:0,他引:1
提出了一种基于标准CMOS工艺的低成本环形补偿振荡器。由于采用了误差反馈补偿技术,该振荡器无需精准的电流源和电压源;利用电阻温度补偿和电源电压稳压,使振荡周期对温度、电压,以及工艺偏差均有较强的容忍能力,且周期大小易于调整。在输入电压范围为4.5~6V,温度范围-40~125℃,以及五个MOSFET工艺偏差的情况下,进行了Hspice仿真。结果表明,在最坏情况下,振荡器周期的最大偏差为7.5%,而在不考虑温度的情况下,由电压和MOSFET工艺变化所引入的振荡周期偏差为0.9%。该振荡器满足电源管理芯片要求,适合低成本DC/DC转换器、充电器等电源管理芯片的应用。 相似文献
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在复杂环境中单个人体的电磁场分布以及SAR计算的比较多,而对多个人体的相互作用以及之间的相互影响研究较少。利用现有的方法,计算在一定条件下,两个体的相互作用,将其计算的结果与单个体存在的情况下的结果相比较由比较了可以得出结论,平面波入射情况下,两个人体存在时的多层SAR与单个体的分层SAR相比差别较小,且比单个人体存在时要小一点。 相似文献
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在理想的情况下.如果数字信号的传输和存储不受制于带宽和容量.那么自然没有人会想要去使用压缩算法。然而事实上,截止到今天,即使随着技术的发展,传输带宽以及存储容量,都在以极高的速度拓宽和扩展,对于数字信号使用尽可能高效的编码方式来兼得较高的音质和较低的数据量仍然是十分必要的事情。在这种情况下.就出现了两类编码方式: 相似文献
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网络流量反映了网络的运行状态,是网络管理领域中重要的研究课题。NetFlow是Cisco公司为实现统计流量而开发的一种协议,使用NetFlow可以方便地进行大规模的流量采集。通过对NetFlow协议原理与功能的分析,设计了一种NetFlow流量分析器。该分析器能够对NetFlow流量数据进行采集和分析,实现网络的异常流量监测、流量计费和综合流量分析,并能及时地发现网络攻击。 相似文献
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Chong-Kwon Kim 《Selected Areas in Communications, IEEE Journal on》1996,14(2):374-385
A multirate multicast switch, which can provide a single uniform switching function for vastly different classes of traffic, is crucial for the successful deployment of integrated broadband networks. We analyze the call blocking probability of heterogeneous circuit switched traffic in a multirate multicast switch using the arrival modulation technique. For the analysis, we introduce two simple traffic models: fan-out heterogeneous traffic and bandwidth heterogeneous traffic. The analysis of two simplified traffic models shows that calls of different characteristics interact in complex yet subtle ways. Our results on fan-out heterogeneous traffic show that the performance gap between large fan-out traffic and small fan-out traffic increases when two types of traffic are mixed. On the other hand, in bandwidth heterogeneous traffic, the performance gap between traffic of different bandwidth decreases. A further investigation indicates that the two types of interactions coexist in general heterogeneous traffic. We conclude the paper introducing several methods to improve the performance of multirate multicast traffic 相似文献
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Wenhong Tian 《Telecommunication Systems》2014,57(1):41-49
Recent studies show that both data traffic and real-time traffic grow very fast in wired and wireless networks. To provide better performance guarantee, these applications need efficient network modeling and planning. In this paper, the problem where the total bandwidth of a link is shared by streaming traffic (real time traffic such as voice or video etc.) and elastic traffic (such as data) is studied. Integrating streaming traffic and elastic traffic presents a unique dimensioning problem. This paper considers dimensioning a link to satisfy both quality of service (QoS) requirements for streaming traffic, such as loss probability, and elastic traffic, such as mean waiting (delay) time. The Erlang loss model is applied to streaming traffic and a bursty traffic model is applied to the elastic traffic. Efficient dimensioning algorithms based on classical Markovian models and time-scale decomposition are then proposed. Numerical results show that the proposed methods have good accuracy. 相似文献
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基于人工电视监视的交通检测方法存在检测效率低、实时性差的缺点,提出了基于视频序列的交通参数和交通事件检测系统。将采集和预处理后的视频信号通过DSP处理,检测视频交通参数和交通事件,提取的交通参数和交通事件等分析结果通过TCP/IP网络传输协议传给视频分析识别终端,在视频分析识别终端上存储、显示交通参数与交通事件和视频信息,设置系统参数,同时可以进行查询、检索以及管理交通参数与交通事件。该系统实现了对车流量、车速、抛落物、行人和停车等交通参数与事件的实时性检测。 相似文献
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随着网络技术不断发展,网络管理者希望对网络流量实行有效管理。在分析当前网络流量和CATV宽带网特征的基础上,提出一种CATV宽带网的流量管理方案,并对该方案采用的客户端/服务器/数据库3层分布式结构进行较为详细的描述。 相似文献
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Much work has focused on traffic grooming in SONET/WDM ring networks. Previous work has considered many aspects of traffic grooming, including minimizing the number of ADMs, minimizing the number of wavelengths, considering different traffic models, using different network architectures, incorporating switching capability and so on. In this work, we study traffic grooming in unidirectional ring networks with no switching capability under both uniform traffic and non-uniform traffic models to reduce electronic multiplexing costs. Based on the clustering notion, we derive a general and tighter lower bound for the number of ADMs required in traffic grooming under the uniform all-to-all traffic model. This bound reduces to special cases obtained in previous work. We also derive general, tighter, and closed form lower bounds for the number of ADMs required under two non-uniform traffic models: the distance-dependent traffic model and the non-uniform symmetric traffic model. Cost-effective multi-phase algorithms that exploit traffic characteristics are then designed and studied to efficiently groom traffic streams under different traffic models. Our numerical and simulation results show that the proposed multi-phase algorithms outperform existing traffic grooming algorithms by using a fewer number of ADMs. Our algorithms in several cases also achieve the lower bounds derived. 相似文献
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Huei-Wen Ferng 《Communications Letters, IEEE》2004,8(7):470-472
Using a general input traffic class rather than confining it to a specific input traffic model, this letter investigates the split traffic for such a general input traffic class under a probabilistic routing algorithm. Thus the obtained result is applicable for a broad range of input traffic. By way of characterizing the split traffic on each routing path, it is shown that the resultant traffic on each routing path is still the same traffic class with suitable parameter modification. 相似文献
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随着我国城市现代化水平的不断提高和经济的快速发展,交通供需矛盾日渐突出,道路交通网络十分脆弱,一旦发生突发事件,极易引发大面积交通拥堵甚至瘫痪,这将引发严重的社会危害。因此,研究突发事件下城市路网交通应急方案具有重要意义。本文在BA网络模型的基础上重现突发事件下的交通拥堵的形成过程,收集形成过程中产生的各项特征参数,分析交通拥堵的形成机理。最后,提出了应对突发事件下交通拥堵的交通路径策略,从而降低突发事件对网络交通的影响。 相似文献
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交通灯的识别对人工智能以及无人驾驶都有着举足轻重的作用,本文研究交通识别中的红绿灯判断,用于改善驾驶员疲劳以及维护交通秩序从而提高驾驶安全系数减少交通事故的发生.通过机器视觉采集红绿灯交通信号图,运用Mat-lab进行图片处理截取红绿灯区域,提取每张图片的121个像素点RGB值,运用1和2分别表示绿灯和红灯,建立红绿灯... 相似文献