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排序方式: 共有264条查询结果,搜索用时 31 毫秒
1.
As the ternary comparator faces problems of slow speed and high power consumption, this paper proposes a scheme for the magnitude ternary comparator of CNFET, which is researching on theory of multi-valued logic circuit and the structure of comparator circuit. First, the ternary decode signal is propagated to the comparator, then the encoder circuit encodes the results of comparison, and finally the magnitude ternary comparator is made up of all kinds of modules. The magnitude comparator is simulated by software, which demonstrates that it has a correct logic function, fast speed and low power consumption characteristics. 相似文献
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Dynamic Adaptive Streaming over HTTP (DASH) is the state-of-the-art technology for video streaming and has been widely deployed in both wired and wireless environments. However, mobile DASH users often suffer from video quality oscillation and even video freeze in wireless environments, which results in poor user experience. This is mainly because most quality adaptation algorithms in DASH rely highly on bandwidth estimation to adjust the video quality while wireless network bandwidth is unstable in nature and changes frequently according to wireless channel contention and condition. To provide stable performance, even during severe bandwidth fluctuation, this paper proposes the Wireless Quality Adaptation (WQUAD) algorithm, which eliminates bandwidth estimation from quality adaptation. Thanks to the Scalable Video Codec (SVC), the proposed scheme always prioritizes to lower layers over higher ones as long as the play-out buffer is not completely filled by the lower layers. As a result, the client always fills the buffer with the base layers first and then the upper enhancement layers sequentially. This horizontal adaptation is straightforward and does not require any bandwidth estimation. Through NS-2 simulations, we show that WQUAD achieves (i) stable performance, keeping the video quality level with respect to the long-term network bandwidth, (ii) effective video freeze prevention, and (iii) high video quality on average. 相似文献
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系统研究了现有语音通信系统中使用的几种语音编解码算法以及主流的单通道语音增强算法,并将二者相结合,对实际通信系统中的结构进行仿真.研究发现,现有的基于线性预测分析技术的语音编解码算法,在高编码率的情况下对于语音增强算法的性能不仅不会有损失,反而会在一定程度上改善增强算法带来的语音失真的情况,提高语音增强算法的效果. 相似文献
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An extended discrete autoregressive model for variable bit rate video traffic encoded by scalable video codec 下载免费PDF全文
Sima Ahmadpour Zohreh Toghrayee Tat‐Chee Wan 《International Journal of Communication Systems》2015,28(18):2239-2254
Designing an effective and high performance network requires accurate characterization and modeling of network traffic. This paper provides a study of the transmission, modeling, and analysis of variable bit rate (VBR) video, which is fundamental for designing protocols and for effective utilization of networks in video transmission. To meet the specified requirements of future networks, the scalable video codec (SVC) was chosen as the video compression standard. The main objective of this work was to propose a statistical model that will allow better coordination between generated SVC video traffic and original video traffic. The performance of the proposed model was evaluated by comparing the model with three existing low‐complex statistical models using graphical and statistical measurements as well as cross‐validation. For all evaluation techniques, the accuracy of the proposed model was evaluated, and the frame size distribution of the modeled traffic was found to match that of the original video traffic better than other existing models. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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近年来流行的网络仿真平台OMNET++由于欠缺对应用层视频特性的考虑而不能有效地评估在视频传输等多媒体业务的要求下无线Ad hoc网络中协议算法的性能。为了解决以上问题,提出了一种OMNET++与H. 264视频编解码器联合仿真的方法,它以H. 264编码器作为OMNET++的数据源,并以H. 264解码器作为视频传输质量的检验平台。利用提出的联合仿真方法,对视频在无线Ad hoc网络中的传输进行了仿真,并评估了该网络中IEEE802. 11多址接入协议的性能。实验表明,提出的联合仿真方法能够为无线Ad hoc网络协议算法的设计与改进提供有效的检验平台。 相似文献
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电信运营商已建成的视频监控系统覆盖城市道路、重要路段、车站、港口、码头、重要单位等,电力系统可通过与电信视频监控系统联网,将其相关的视频信号接入电力系统,实现所需场景的实时监控,这样既减少了设备投资,又解决了电力监控布点问题。文章基于软交换技术的控制与媒体分离的核心思想,提出一种电力内外网视频安全隔离技术方案。方案采用视频控制与视频传输分离的方式。研究应用了外网视频通信技术、视频编解码技术、内外网信息隔离技术,重点研究应用外网视频信号传输至电力系统的安全隔离技术,为电力系统各种视频业务应用提供更广泛、更全面的远程现场监控技术支撑。 相似文献
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为提高低压配网电力线信道中的信息传输效率,提出一种优化BP译码的改进4折线算法。通过变换化简置信传播(belief propagation,BP)算法的校验节点信息更新函数,建立分段线性函数,并设计误差修正表对不同分段区间进行补偿,利用查表方法实现误差修正值,可降低解码实现复杂度。在Middleton A类电力线信道模型下的仿真结果表明,经分段线性函数优化后的译码算法与BP算法的误码率(bit error rate,BER)性能相近,而译码的复杂度却大大降低,有利于算法的软硬件实现,为电力线载波通信提供了一种高性能的信道编码方案。 相似文献