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
Sparse arrays of telescopes have a limited (u, v)-plane coverage. In this paper, an optimization method for designing planar arrays of an aperture synthesis telescope is proposed that is based on distributed genetic a...Sparse arrays of telescopes have a limited (u, v)-plane coverage. In this paper, an optimization method for designing planar arrays of an aperture synthesis telescope is proposed that is based on distributed genetic algorithm. This distributed genetic algorithm is implemented on a network of workstations using community communication model. Such an aperture synthesis system performs with imperfection of (u, v) components caused by deviations and(or) some missing baselines. With the maximum (u, v)-plane coverage of this rotation-optimized array, the image of the source reconstructed by inverse Fourier transform is satisfactory.展开更多
This paper aims to present a role-based interaction model for dynamic service composition in Grid environments. Assigning roles to a service means to associate with it capabilities that describes all the operations th...This paper aims to present a role-based interaction model for dynamic service composition in Grid environments. Assigning roles to a service means to associate with it capabilities that describes all the operations the service intends to perform. When all of the services can be recognized by their roles, the appropriate services can be selected. Based on the interaction policy, a role-based interaction model not only facilitates access control, but also offers flexible interaction mechanism for adapting service-oriented applications. This interaction model adopts programmable reactive tuple space to facilitate context-dependent coordination.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.
基金This project was supported by the High Technology Research and Development Programme of China (2002AA111040).
文摘Sparse arrays of telescopes have a limited (u, v)-plane coverage. In this paper, an optimization method for designing planar arrays of an aperture synthesis telescope is proposed that is based on distributed genetic algorithm. This distributed genetic algorithm is implemented on a network of workstations using community communication model. Such an aperture synthesis system performs with imperfection of (u, v) components caused by deviations and(or) some missing baselines. With the maximum (u, v)-plane coverage of this rotation-optimized array, the image of the source reconstructed by inverse Fourier transform is satisfactory.
文摘This paper aims to present a role-based interaction model for dynamic service composition in Grid environments. Assigning roles to a service means to associate with it capabilities that describes all the operations the service intends to perform. When all of the services can be recognized by their roles, the appropriate services can be selected. Based on the interaction policy, a role-based interaction model not only facilitates access control, but also offers flexible interaction mechanism for adapting service-oriented applications. This interaction model adopts programmable reactive tuple space to facilitate context-dependent coordination.
