In local high-speed network, the performance of VOD system is limited by disk-bound. In this paper, we propose an enhanced video-on-demand delivery policy based on dynamic buffering algorithm. Considering the control...In local high-speed network, the performance of VOD system is limited by disk-bound. In this paper, we propose an enhanced video-on-demand delivery policy based on dynamic buffering algorithm. Considering the controllable bandwidth allocation for multicast and the characteristics of on-demand video, we optimize the disk access performance of video sever to fully utilize the I/O capability of disk and the bandwidth of network. For a practical VOD system, this strategy can supply instantaneous video-on-demand services and maximum on-demand video number cheaply.展开更多
交通路况监控与意外事故处理是我国的一个重要难题.为解决固定摄像机监控盲区及视频清晰度不足的问题,提出了基于4G的移动实时视频传输系统.简要阐述了系统的整体框架与层次结构,并引入基于Reactor模型的高并发I/O复用方式,在此基础上...交通路况监控与意外事故处理是我国的一个重要难题.为解决固定摄像机监控盲区及视频清晰度不足的问题,提出了基于4G的移动实时视频传输系统.简要阐述了系统的整体框架与层次结构,并引入基于Reactor模型的高并发I/O复用方式,在此基础上设计了一种基于动态缓冲区的发送端速率控制方法,实现了移动视频的QoS(Quality of Service)质量保障.实验结果表明在4G网络环境下,移动实时视频传输稳定,清晰度高,可应用于对交通路况的监测与实时控制.展开更多
The landing buffer is an important problem in the research on bionic locust jumping robots, and the different modes of landing and buffering can affect the dynamic performance of the buffering process significantly. B...The landing buffer is an important problem in the research on bionic locust jumping robots, and the different modes of landing and buffering can affect the dynamic performance of the buffering process significantly. Based on an experimental observation, the different modes of landing and buffering are determined, which include the different numbers of landing legs and different motion modes of legs in the buffering process. Then a bionic locust mechanism is established, and the springs are used to replace the leg muscles to achieve a buffering effect. To reveal the dynamic performance in the buffering process of the bionic locust mechanism, a dynamic model is established with different modes of landing and buffering. In particular, to analyze the buffering process conveniently, an equivalent vibration dynamic model of the bionic locust mechanism is proposed.Given the support forces of the ground to the leg links, which can be obtained from the dynamic model, the spring forces of the legs and the impact resistance of each leg are the important parameters affecting buffering performance, and evaluation principles for buffering performance are proposed according to the aforementioned parameters. Based on the dynamic model and these evaluation principles, the buffering performances are analyzed and compared in different modes of landing and buffering on a horizontal plane and an inclined plane. The results show that the mechanism with the ends of the legs sliding can obtain a better dynamic performance. This study offers primary theories for buffering dynamics and an evaluation of landing buffer performance,and it establishes a theoretical basis for studies and engineering applications.展开更多
文摘In local high-speed network, the performance of VOD system is limited by disk-bound. In this paper, we propose an enhanced video-on-demand delivery policy based on dynamic buffering algorithm. Considering the controllable bandwidth allocation for multicast and the characteristics of on-demand video, we optimize the disk access performance of video sever to fully utilize the I/O capability of disk and the bandwidth of network. For a practical VOD system, this strategy can supply instantaneous video-on-demand services and maximum on-demand video number cheaply.
文摘交通路况监控与意外事故处理是我国的一个重要难题.为解决固定摄像机监控盲区及视频清晰度不足的问题,提出了基于4G的移动实时视频传输系统.简要阐述了系统的整体框架与层次结构,并引入基于Reactor模型的高并发I/O复用方式,在此基础上设计了一种基于动态缓冲区的发送端速率控制方法,实现了移动视频的QoS(Quality of Service)质量保障.实验结果表明在4G网络环境下,移动实时视频传输稳定,清晰度高,可应用于对交通路况的监测与实时控制.
基金supported by the National Natural Science Foundation of China (Grant 51375035)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant 20121102110021)
文摘The landing buffer is an important problem in the research on bionic locust jumping robots, and the different modes of landing and buffering can affect the dynamic performance of the buffering process significantly. Based on an experimental observation, the different modes of landing and buffering are determined, which include the different numbers of landing legs and different motion modes of legs in the buffering process. Then a bionic locust mechanism is established, and the springs are used to replace the leg muscles to achieve a buffering effect. To reveal the dynamic performance in the buffering process of the bionic locust mechanism, a dynamic model is established with different modes of landing and buffering. In particular, to analyze the buffering process conveniently, an equivalent vibration dynamic model of the bionic locust mechanism is proposed.Given the support forces of the ground to the leg links, which can be obtained from the dynamic model, the spring forces of the legs and the impact resistance of each leg are the important parameters affecting buffering performance, and evaluation principles for buffering performance are proposed according to the aforementioned parameters. Based on the dynamic model and these evaluation principles, the buffering performances are analyzed and compared in different modes of landing and buffering on a horizontal plane and an inclined plane. The results show that the mechanism with the ends of the legs sliding can obtain a better dynamic performance. This study offers primary theories for buffering dynamics and an evaluation of landing buffer performance,and it establishes a theoretical basis for studies and engineering applications.
