多服务WiMAX系统的调度与资源分配策略

基于IEEE802.16标准的WiMAX技术已成为宽带无线接入的主要技术,IEEE802.16标准没有规定调度和资源分配策略,网络运营商可以自行选择。根据用户需求并考虑信道条件的影响,提出基于NS2的扩展WiMAX系统级仿真平台,给出一种公平有效的调度与资源分配策略。仿真结果证明该策略可以满足多种服务流的QoS需求并最大化系统吞吐量。     

多项目选择计划及其两层决策免疫遗传算法

探讨项目计划管理中,资源受限下含承继约束的多项目选择计划两级规划模型及其求解算法.依据项目的承继关系,将所有项目划分为若干子群,各子群内部的项目之间存在承继约束,子群之间仅有优先关系,进而获得了资源受限下资源配置平衡的两级规划模型.基于遗传算法的基本结构,引入免疫系统的多样性、记忆性等特征,获得了求解此模型的免疫遗传算法.数值实验结果表明了该模型设计的合理性及算法的有效性.     

不确定条件下控制分配问题的鲁棒优化方法

针对具有冗余执行机构的过驱动系统, 在考虑控制效率不确定性的条件下, 提出了一种基于鲁棒优化理论的控制分配算法. 研究了原始不确定鲁棒优化模型的建立和基于椭球不确定集的鲁棒对等式的转化问题, 并推广到可由锥二次不等式表示的不确定集的情况. 讨论了鲁棒优化控制分配算法的求解方法及其计算复杂度. 最后, 针对多操纵面飞机的最优控制分配问题与传统算法进行了仿真比较, 结果表明鲁棒优化算法能有效降低控制效率不确定性的影响, 使分配结果更为合理, 从而具有更好的鲁棒性, 同时能有效提高操纵面故障情况下闭环系统的控制重构能力, 很好地改善了飞控系统的性能.     

基于RBS 的合作通信网络公平合作策略

针对合作通信网络中基于纳什议价解(NBS)的合作策略存在用户效用分配不公平的问题,同时考虑用户的最大与最小效用,提出了基于Raiffa-Kalai-Smorodinsk议价解(RBS)的合作策略,并建立了用户合作的条件.仿真结果表明,基于RBS的合作策略在保证网络总效用不变的前提下,具有更好的公平性.     

一种基于系统总误码率的协同伙伴选择算法

提出了一种基于系统总误码率的协同伙伴选择算法。当系统总发送功率一定时,通过系统误码率公式,采用带CRC校验的DF协同通信的协同增益,来降低系统总的误码率。仿真表明,此算法有效地降低了系统总误码率,并且系统SNR越大,协同通信对系统数据传输的帮助越明显。     

电力线通信中动态子载波组分配

针对电力线通信自适应OFDM系统的限制条件,探讨在每OFDM符号内各RT用户要求的约束下,研究系统总功率地窖注水分配后多子载波上的速率自适应子载波分配模型,提出一种新的动态子载波组分配算法。在典型电力线信道环境下对其仿真,并与另外两种分配算法进行比较,结果表明,本文动态子载波组分配算法的复杂度大大减小,能满足多用户资源分配的多目标要求。     

Bicriteria robotic operation allocation in a flexible manufacturing cell

Consider a manufacturing cell of two identical CNC machines and a material handling robot. Identical parts requesting the completion of a number of operations are to be produced in a cyclic scheduling environment through a flow shop type setting. The existing studies in the literature overlook the flexibility of the CNC machines by assuming that both the allocation of the operations to the machines as well as their respective processing times are fixed. Consequently, the provided results may be either suboptimal or valid under unnecessarily limiting assumptions for a flexible manufacturing cell. The allocations of the operations to the two machines and the processing time of an operation on a machine can be changed by altering the machining conditions of that machine such as the speed and the feed rate in a CNC turning machine. Such flexibilities constitute the point of origin of the current study. The allocation of the operations to the machines and the machining conditions of the machines affect the processing times which, in turn, affect the cycle time. On the other hand, the machining conditions also affect the manufacturing cost. This study is the first to consider a bicriteria model which determines the allocation of the operations to the machines, the processing times of the operations on the machines, and the robot move sequence that jointly minimize the cycle time and the total manufacturing cost. We provide algorithms for the two 1-unit cycles and test their efficiency in terms of the solution quality and the computation time by a wide range of experiments on varying design parameters.     

Distributed bandwidth allocation based on alternating evolution algorithm

In a network, end nodes have to compete for bandwidth through some distributed congestion control algorithms. It is a great challenge to ensure the efficiency and fairness of the distributed control algorithms. TCP congestion control algorithms do not perform well in terms of their efficiency and fairness in high speed networks. In this paper, we propose a novel asymptotic evolution algorithm based on the Logistic Model to allocate limited bandwidth resource. The algorithm introduces an explicit bandwidth pre-allocation factor. The factor is carried by the packet and is computed in routers based on the information of the router capacity, the aggregate load, and the instantaneous queue length; therefore the algorithm does not require the routers to keep the per-flow state. According to this pre-allocation bandwidth factor, the senders asymptotically adjust their sending rate and the bandwidth factor changes asymptotically along with the variation of the aggregate load and the queue length in the routers; therefore the sending rate and the pre-allocation bandwidth factor form alternating evolution and eventually reach a steady state.     

嵌入式Linux平台内存管理方案

不同的动态内存分配算法往往应用于不同场景、面向于不同业务,因此衡量指标不一,性能各异.针对多模式、多业务的数字电视终端,本文提出了一种嵌入式L inux平台内存管理方案,深入剖析了共享内存的原理及方法,采用共享内存技术支撑多业务开展,同时实现了一种使用二级索引策略的动态内存分配算法,复杂度为O(1),相比其他经典算法,实时性高而碎片率低,仿真性能良好,并在嵌入式平台上实施,取得了不错的效果.     

认知网络中基于竞价模型的切换频谱分配

通过对最新竞价算法的分析,针对频谱分配过程中频谱使用率低下的缺点,提出一种认知无线电中基于竞价机制的具有较高频谱使用率的频谱分配算法。引入干扰价格,通过设置干扰价格指数,降低系统干扰,保证主用户的服务质量。数值仿真结果表明,该算法通过多次分配有效地提高了频谱的利用率,增加了系统的吞吐量。