网格资源管理系统模型研究

网格资源管理系统是网格计算系统的重要组成部分。文章分析了网格资源管理系统的功能需求，具体论述了该模型的原型系统，最后介绍了相关研究工作。     

基于多信道预约可冲突避免的多址接入协议

本文为多跳分布多无线网络提出了一套灵活而有效的自适应获取冲突避免（AACA）的多址接入协议。在该协议中，各节点竞争公共信道，利用RTS/CTS对话形式来预约各业务信道，成功预约后的分组传输不会受到其他节点的干扰。它使用任意确定数目信道，以异步方式工作，并且使得各节点利用半双工无线电台就可以灵活、简便地实现资源预约。分析和比较结果说明，所提出的多信道预约协议可以有效地解决隐藏终端、暴露终端以及侵入终端的问题。     

基于双阈值的视频平滑控制方法

在现有的TCP／IP网络中进行多媒体通信，服务质量是人们关注的重要内容。作为服务质量中的一项指标，视频平滑已成为研究和应用开发的一个热点问题。分析当前控制视频平滑的方式，提出一种基于双阈值视频平滑的控制方法。这种方法能够有效地改善视频平滑性能。     

Engset multi‐rate state‐dependent loss models with QoS guarantee

We consider a single link loss system of quasi‐random input, described by the Engset multirate loss model (EnMLM). Blocked calls may once reattempt to be connected to the system requiring less bandwidth; then the system is described by the single retry model for finite sources (f‐SRM). The EnMLM and the f‐SRM are extended with the single threshold finite source model (f‐STM), where calls may attempt to be connected to the system with less bandwidth requirements, according to the link occupancy, before blocking occurs. We focus on CBP equalization in the EnMLM, f‐SRM and f‐STM, under the bandwidth reservation (BR) policy. For this analysis, we apply two approximate methods, the Roberts' method and the method of reverse transition rates (RTR), which lead to a recursive CBP calculation. We evaluate the accuracy of the above models under the BR policy by comparing the analytical with simulation CBP results, based on the relative approximation errors (RAE). The results are highly satisfactory because they show that the proposed models (formulas) lead to small RAE. Copyright © 2005 John Wiley & Sons, Ltd.     

酒店信息搜索系统设计

讲解使用Google Map API确定酒店地理位置,并对酒店周边的信息进行搜索。     

802.11 DCF协议引入信道预约机制的必要性分析

论文对802.11 DCF协议引入信道预约机制的必要性问题进行了探讨.通过分析信道预约机制与隐藏/暴露终端问题之间的关系,提出一种比较隐藏终端和暴露终端出现概率大小的等效方法,并给出了相应的数值估算结果.理论分析结果验证了802.11 DCF协议引入信道预约机制的有效性.     

支持多通道传输的光子网格资源并行调度策略

为满足分布式业务对资源使用灵活性和网络高带宽性的要求,实现高性能光网络,对光子网格体系结构进行了研究,并提出支持多通道传输的光子网格资源并行调度策略. 利用可分负载均衡策略分割数据或执行大文件分片,结合多波长并行预留机制,在应用驱动下按需分配光路资源. 构建光子网格实验平台,以电力分布式潮流数据传输应用为例验证所提策略的有效性. 实验结果表明,在应用驱动下并行调度策略能提供灵活的光网络资源分配,有效提高分布式业务的传输性能及光网络资源利用效率.     

基于预留带宽的光纤通道交换网硬实时通信

为了保证光纤通道(FC)交换网中硬实时通信,提出一种采用通用处理器共享(generalized processor sharing)调度方式交换机构建交换网,并且采用模拟退化算法根据数据流硬实时通信需求找出交换网ISL(inter-switch link)权重参数和数据流预留带宽参数优化配置的方法.在对FC网络以及GPS调度方式进行分析的基础上,建立基于光纤通道交换网的硬实时通信模型,将保证硬实时通信问题转换为组合优化问题;构造了最小预留带宽和目标函数,并采用模拟退火算法找出该问题的最优解.仿真实验结果验证了该方法的有效性,但是通过可接受解和最优解的实验结果比较发现最优解并不能总是获得最佳的系统延迟时间率.     

基于Android的总量优先预算算法在订餐系统的使用

本文主要介绍了一款使用了总量优先预算算法的订餐预算系统的开发过程及关键技术。该系统主要包括,数据导入、算法设置、预算、统计等主要功能。该系统主要为快速餐饮行业提供食物原材料准备、初期加工等预算功能。     

Implementation of call admission control scheme in next generation mobile communication networks using particle swarm optimization and fuzzy logic systems

In the present and next generation wireless networks, cellular system remains the major method of telecommunication infrastructure. Since the characteristic of the resource constraint, call admission control is required to address the limited resource problem in wireless network. The call dropping probability and call blocking probability are the major performance metrics for quality of service (QoS) in wireless network. Many call admission control mechanisms have been proposed in the literature to decrease connection dropping probability for handoffs and new call blocking probability in cellular communications. In this paper, we proposed an adaptive call admission control and bandwidth reservation scheme using fuzzy logic control concept to reduce the forced termination probability of multimedia handoffs. Meanwhile, we adopt particle swarm optimization (PSO) technique to adjust the parameters of the membership functions in the proposed fuzzy logic systems. The simulation results show that the proposed scheme can achieve satisfactory performance when performance metrics are measured in terms of the forced termination probability for the handoffs, the call blocking probability for the new connections and bandwidth utilization.