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针对目前基于发送速率的自适应视频传输算法不能有效利用和适应网络传输,提出了利用数据缓冲占用比的无人机载视频自适应无线传输方法;通过计算发送缓存内的数据占空比的变化判断网络发送能力,进而调节下次采集的视频帧率,或在调节下次采集视频帧率之前调整压缩编码率,由此自适应的设置最大化传输速率;相对于传统基于线性增加发送速率的方法,文章算法根据数据占空比自动调节发送速率和编码率,使平均发送速率提高了0.25 Mbit/s,带宽利用率提高了8%,实现了在不同网络状况下发送速率和编码率的自适应最大化,通过有效利用网络传输,提高视频数据传输的实时性、可靠性和完整性。 相似文献
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针对现有交通监控视频中采用的H.264算法复杂度高、运算量大、误码跨帧传播等问题,提出了基于专用编解码芯片ADV212硬件实现JPEG2000标准的视频压缩传输系统的设计方法。设计以ADV7180对PAL制式模拟视频进行采集,以ADV212完成对采集后视频数据的压缩处理,最后通过DM9000A实现对压缩数据的以太网传输。FPGA作为系统主控,主要实现对各芯片的初始化及逻辑控制。实验结果表明,在保证压缩图像具有较高峰值信噪比的情况下,系统对速率为166Mbps的视频图像进行压缩处理后输出速率为8Mbps,有效减轻了网络传输带宽压力,且便于网络终端进行视频数据存储。同时系统还具有集成度高、体积小、性价比高、压缩比可调等优点,支持多种视频监控场合使用。 相似文献
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采用交换式以太网技术设计GSM-R场强测试系统,以完成测试列车运行时速大于250公里时铁路沿线GSM-R场强分布情况,包括场强数据的采集、实时曲线显示、数据回放显示及后期分析;介绍了Truetime仿真工具箱的使用,包括Truetime内核模块、网络模块、ttSendMsg模块、ttGetMsg模块等,对GSM-R场强测试网络设计了一个模型来模拟GSM-R场强数据的传输,使用Tru-etime工具箱模拟分析了网络类型、数据传输速率、交换机缓存容量和网络丢包率对数据传输的影响,结果表明使用交换式以太网技术设计系统可以满足高速列车GSM-R场强测试的要求。 相似文献
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针对传统模拟信号监控的不足,设计了一种基于S3C6410硬件平台、Linux2.6软件平台、H.264标准及运动检测算法和WIFI无线网络传输的井下视频监控系统;针对井下监控背景基本不变,采用H.264图像压缩算法以及改进的单高斯模型运动检测算法;并提出了整体监控软件的设计方案;最后通过PSNR、压缩比、压缩时间以及压缩速率等参数对算法进行了实验,实验结果表明:该系统能在较低的编码速率上实现较好的成像质量,具有较高的压缩质量,可满足实时编码需求。 相似文献
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以无压缩全高清视频的光载无线传输为背景,通过研究宽带射频光子下转换技术,从而构建全高清视频的实时传输系统,其中下转换系统主要基于光电振荡器实现.由于光电振荡器的注入锁定,光微波信号中的载波信号被提取出来,并反馈至调制器,与宽带光微波信号混频,在光域实现信号下转换.实验论证了载频为10GHz,码率大于2Gb/s的信号下转换和有线无线传输.利用天线和光纤实现了距离为0.5m的无线分发和距离为10km的有线传输.本文还成功实现了1.5Gb/s无压缩高清视频信号的实时传输.实验结果表明,该系统具有大带宽、抗电磁干扰等优点,同时利用光电振荡器的自动相位跟踪技术,无须外加锁相等操作.整个下转换系统简单稳定,为高清视频的有线无线传输提供了论证和演示平台. 相似文献
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以无压缩全高清视频的光载无线传输为背景,通过研究宽带射频光子下转换技术,从而构建全高清视频的实时传输系统,其中下转换系统主要基于光电振荡器实现.由于光电振荡器的注入锁定,光微波信号中的载波信号被提取出来,并反馈至调制器,与宽带光微波信号混频,在光域实现信号下转换.实验论证了载频为10GHz,码率大于2Gb/s的信号下转换和有线无线传输.利用天线和光纤实现了距离为0.5 m的无线分发和距离为10km的有线传输.本文还成功实现了1.5Gb/s无压缩高清视频信号的实时传输.实验结果表明,该系统具有大带宽、抗电磁干扰等优点,同时利用光电振荡器的自动相位跟踪技术,无须外加锁相等操作.整个下转换系统简单稳定,为高清视频的有线无线传输提供了论证和演示平台. 相似文献
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Traffic capacity of one network strongly depends on the link’s bandwidth allocation strategy. In previous bandwidth allocation mechanisms, once one link’s bandwidth is allocated, it will be fixed throughout the overall traffic transmission process. However, the traffic load of every link changes from time to time. In this paper, with finite total bandwidth resource of the network, we propose to dynamically allocate the total bandwidth resource in which each link’s bandwidth is proportional to the queue length of the output buffer of the link per time step. With plenty of data packets in the network, the traffic handling ability of all links of the network achieves full utilization. The theoretical analysis and the extensive simulation results on complex networks are consistent. This work is valuable for network service providers to improve network performance or to do reasonable network design efficiently. 相似文献
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High bit rate systems can be achieved by operating at the wavelength of zero second order dispersion in optical fibres. The bandwidth is then limited by higher order dispersion terms. We consider the propagation of high intensity pulses in such a system, where the Kerr effect cannot be ignored. It is shown that the bandwidth is further limited by the optical nonlinearity. 相似文献
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Rajat Kumar Singh Rajiv Srivastava Yatindra Nath Singh 《Optical and Quantum Electronics》2007,39(1):15-34
Photonic all-optical switching is widely considered as one of the technique to utilize the enormous optical bandwidth. Optical
packet switching provides high speed, data rate transparency, data format transparency, efficient use of bandwidth and flexibility.
To resolve the conflict during contention, packets are needed to be buffered. Due to the lack of optical RAM, fiber delay
lines (FDLs) are the most suited option to buffer the packets. This paper proposes new optical packet switch architecture
alongwith feedback shared buffer utilizing the advantage of WDM loop buffer memory. The loop buffer module used in this switch
architecture is a new approach towards WDM buffering of packets. The mathematical modeling is done to validate the results
obtained from simulation. 相似文献
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《Journal of sound and vibration》2004,269(3-5):1031-1062
A high bandwidth powered resonance tube (PRT) actuator potentially useful for noise and flow control applications was developed. High bandwidth allows use of the same actuator at various locations on an aircraft and over a range of flight speeds. The actuator selected for bandwidth enhancement was the PRT actuator, which is an adaptation of the Hartmann whistle. The device is capable of producing high-frequency and high-amplitude pressure and velocity perturbations for active flow control applications. Our detailed experiments aimed at understanding the PRT phenomenon are complemented by an improved analytical model and direct numerical simulations. We provide a detailed characterization of the unsteady pressures in the nearfield of the actuator using phase averaged pressure measurements. The measurements revealed that propagating fluctuations at 9 kHz were biased towards the upstream direction (relative to the supply jet). A complementary computational study validated by our experiments was useful in simulating the details in the region between the supply jet and the resonance tube where it was difficult to gather experimental data. High bandwidth was obtained by varying the depth of the resonance tube that determines the frequency produced by the device. Our actuator could produce frequencies ranging from 1600 to 15,000 Hz at amplitudes as high as 160 dB near the source. The frequency variation with depth is predicted well by the quarter wavelength formula for deep tubes but the formula becomes increasingly inaccurate as the tube depth is decreased. An improved analytical model was developed, in which the compliance and mass of the fluid in the integration slot is incorporated into the prediction of resonance frequencies of the system. Finally a feedback controller that varied both the resonance tube depth and spacing to converge on a desired frequency was developed and demonstrated. We are optimistic that numerous potential applications exist for such high bandwidth high dynamic range actuators. 相似文献
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FlexRay以其实时性、灵活性、高带宽的优势,被称为“下一代车载网络”;然而其协议相对复杂,网络组网调试过程较困难。目前的辅助调试工具如CANoe不能进一步分析网络性能,在应用上具有局限性。针对上述问题,提出了一种同时对多个数据采集与存储的解决方案,并以FPGA为核心设计了FlexRay网络监控平台,利用SPI和USB总线设计了通信协议,在数据缓存方面设计了三级队列缓存方案。本平台实现了通信数据监测功能,可以获取结点CPU中寄存器状态、记录数据帧到达时间,进而分析网络运行及故障状态,同时解决了大量数据缓存溢出的问题。经过测试表明:系统能够稳定运行,适用于快速、优化地设计FlexRay网络。 相似文献
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研究了带有连接边传输容量(带宽)约束的复杂网络上如何提升网络数据流负载问题. 在网络连接边带宽资源总量固定的条件下, 提出了一种异质化带宽分配方案. 引入 "受控边" 概念, 通过加入适当比例的 "受控边", 重新分配带宽资源, 并结合具有拥塞感知能力路由策略的数据流量模型, 利用带宽分配调节数据流量走向, 提高了带宽利用效率, 最终使得网络整体的负载能力较带宽匀质化分配时有显著提升. 分别在Barabási-Albert无标度网络和Watts-Strogtz (WS)小世界网络平台上仿真, 发现按照本文的带宽分配方案, WS小世界网络中节点连接边带宽与网络负载有较强的相关性, 节点连接边带宽分配最均衡的时候, 网络负载能力达到最大.
关键词:
异质化带宽分配
负载
介数
受控边 相似文献