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The impact of MAC parameters on the performance of 802.15.4 PAN 总被引:1,自引:0,他引:1
The operation of a personal area network, operating under the IEEE Standard 802.15.4 in the beacon enabled mode, is analyzed using the theory of discrete time Markov chains and M/G/1/K queues. The model includes the impact of different parameters such as packet arrival rate, number of stations, station’s buffer size, packet size, and inactive period between the beacons. We have derived several important performance parameters such as probability of access, probability that medium is idle, queue length distribution in the device, and probability distribution of the packet service time. Some important conclusions regarding the implementation of 802.15.4 networks and compatible network devices are outlined. 相似文献
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Fourier based methods are still popular for calculating power quality indices (PQIs) in the technical community such as IEC and IEEE. They are robust towards noise and can be calculated efficiently using the fast Fourier transform (FFT) method. IEEE Std 1459-2010 provides formulations for calculating important PQI for single and three phase systems. The aim of this paper is to present the theory for estimating PQIs using the Welch spectral and cross spectral analysis techniques, and show experimentally the accuracy of the proposed methods when calculating the PQIs. Further it provides a comparison on the windowing techniques (WTs) that accompany the PQI estimations when using FFT based methods. This information has not been documented extensively in the technical literature when trying to calculate the PQI as specified by IEEE Std 1459-2010. Further we present a virtual instrument (VI) with a Kalman filter (KF) to estimate the PQIs. The KF is used to reduce the variance in measurements for the PQI estimation. We also compare experimentally the accuracy of the VI without the KF with the VI using the KF. Specifically we propose good and bad WTs to estimate such PQIs. 相似文献
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本文筒述了目前国内外精密时钟技术在国内外研究、发展以及IEEEstdC37.238国际标准的情况,同时,推荐了智能变电应用的报文格式、传输模式以及组网应用的方式;根据IEEE1588国际标准明确了网络节点对频率调整和相位调整的技术要求.着重分析了本地时钟抖动和漂移、网络中异常PTP报文以及主钟切换带来的网络问题和解决方法。 相似文献
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IEEE Std 1641标准是下一代自动测试系统研制中的重要理论依据,但针对总线信号标准仅给出了RS422总线信号模型;GJB289A总线是航空领域中的一种常用总线,因此对该信号模型的研究是测试领域的热点之一.针对实际应用中的复杂测试需求,建立了一种不同的基于IEEE Std 1641标准的GJB289A信号模型,并给出了应用实例.最后针对国内的研究应用状况,给出了一点建议. 相似文献
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高技术产业链自动化——现代超级计算机与超大规模集成电路产业链自动化将形成BACNet+HBES+CC-Links+eFactory高技术新市场的分析——2.探寻日本地震-海啸造成福岛核电7级事故的原因
沈经 《仪器仪表标准化与计量》2011,(2):1-9
在2007年日本新澙地震刈羽核电事故分析基础上,分析了2011年日本东北近海地震-海啸致福岛7级核电事故,发现有严重不符IEC61508风险-SIL准则的7处"冒险点"!结论是:核电需改革垄断封闭,宜联合基础工业,共同发展。 相似文献
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