MIMO链路ad hoc网络传输调度算法

针对MIMO链路ad hoc网络中已有传输调度算法未充分利用MIMO空间复用能力的问题,提出了一种新的传输调度算法.该算法通过考虑MIMO的多流接收能力而有效地减小了调度帧长,通过合理安排节点分配顺序使得节点分配的数据流比较平均,同时,该算法通过允许节点发送多个数据流而高效利用了MIMO的空间复用能力.推导分析了传输调度算法的通过量和时延性能,结果表明,与已有算法相比,采用文中算法可以提高网络的通过量,减小网络的平均时延和最大时延.     

支持公平服务的CICQ分层混合调度策略

为到达业务提供性能保障是衡量一个交换系统性能的重要参考.针对现有联合输入交叉点排队交换结构(CICQ)调度策略缺乏基于流的服务质量保障,探讨了在CICQ交换结构实施基于"流"调度的可能性,提出了一种能够为到达业务流的提供公平服务的分层混合调度策略(HSFS).HSFS采用分层的混合调度机制,每个输入、输出端口可独立地进行变长分组交换,其复杂度为O(1),具有良好可扩展特性.理论分析结果表明,HSFS无需加速便能为到达业务提供时延上限、速率和公平性保障.最后,基于SPES对HSFS的性能进行了评估.     

Achieving fair service with a hybrid scheduling scheme for CICQ switches

Providing performance guarantees for arriving traffic flows has become an important measure for today’s routing and switching systems. However, none of current scheduling algorithms built on CICQ (combined input and cross-point buffered) switches can provide flow level performance guarantees. Aiming at meeting this requirement, the feasibility of implementing flow level scheduling is discussed thoroughly. Then, based on the discussion, it comes up with a hybrid and stratified fair scheduling (HSFS) scheme, which is hierarchical and hybrid, for CICQ switches. With HSFS, each input port and output port can schedule variable length packets independently with a complexity of O(1). Theoretical analysis show that HSFS can provide delay bound, service rate and fair performance guarantees without speedup. Finally, we implement HSFS in SPES (switch performance evaluation system) to verify the analytical results.     

SCHEDULING PARALLEL PROGRAM TASKS WITH NON-NEGLIGIBLE INTERTASK COMMUNICATIONS ON TO NUMA MULTIPROCESSOR SYSTEMS

The purpose of this paper is to examine the impact of scheduling parallel tasks onto non-uniform memory access (NUMA) shared-memory multiprocessor systems by considering non-negligible intertask communications and communication contentions. Communication contentions arise from the communication medium having insufficient capacity to serve all transmissions, thereby causing significant contention delays. Therefore, a new scheduling algorithm, herein referred to as the Extended Critical Path (ECP) algorithm is proposed. The proposed algorithm schedules parallel tasks by considering non-negligible intertask communications and the contentions among shared communication resources. Moreover, it ensures performance within a factor of two of the optimum for general directed acyclic task graphs (DATGs). Experimental results demonstrate the superiority of the ECP algorithm over the scheduling algorithms presented in previous literature.     

PERFORMANCE ANALYSIS OF TASK CLUSTERING HEURISTICS FOR SCHEDULING STATIC DAGS ON MULTIPROCESSOR SYSTEM*

CASS is a task management system that provides facilities for automatic grain-size optimization and task scheduling of parallel programs on distributed memory parallel architectures. The heart of CASS is a clustering module that partitions the tasks of a program into clusters that match the granularity of the target machine. This paper describes the clustering algorithms used by CASS and compares them with the best known algorithms reported in the literature, namely the PY algorithm (for clustering with task duplication) and the DSC algorithm (for clustering with no task duplication). It is shown that the clustering algorithms used by CASS outperform both the PY and DSC algorithms in terms of both speed and solution quality.     

多资源公平调度器在Hadoop 中的实现

目前Hadoop的作业调度算法都是将系统中的多类资源抽象成单一资源,分配给作业的资源均是节点资源中固定大小的一部分,称为插槽。这类基于插槽的算法没有考虑到系统多资源的差异性,忽略了不同类型作业对资源的不同需求,因此导致系统在吞吐量和平均作业完成时间上性能低下。本文研究了多资源环境下公平调度算法在Hadoop中的实现,设计了一种多资源公平调度器MFS(Multi-resource Fair Scheduler)。MFS采用了DRF(Dominant Resource Fairness)调度思想,使用需求向量来描述作业对各类资源的需求,并按照需求向量中各资源的大小给作业分配资源。MFS能更加充分有效地使用系统的各类资源,并能满足不同类型作业对资源的不同需求。实验表明相比于基于插槽的Fair Scheduler与Capacity Scheduler,MFS提高了系统的吞吐量,降低了平均作业完成时间。     

物联网在公交车智能监控调度系统中的应用研究

介绍了物联网技术的概念、基本特征、发展现状以及物联网中的关键技术,提出了一种公交车智能监控调度模型,并分析了该系统架构中各个模块的功能,以便在一定程度上促进公交系统的发展,同时也促进物联网的建设与发展。     

高速分组交换网络中调度器的设计

为了满足迅猛发展的网络业务对网络服务质量提出的更高要求,使用高速分组网络交换机中的队列调度器可以有效地提供高质量的网络服务。通过采用分级式队列调度和四种队列调度算法有效地实现了队列调度器的设计。并且深入地比较和分析了队列调度器中多种队列调度算法的优缺点,尤其是对DRR调度算法进行了优化和改进。最后。对所设计的电路进行了仿真验证和电路综合,结果表明该调度器可以满足网络对服务质量的更高要求,并且能够应用到高速分组交换网络的调度器设计中。     

基于基因表达式的克隆选择算法求解JSP问题

针对作业车间调度问题的特征,提出一种基于基因表达式的克隆选择算法。在这个方法中,采用基因表达式编程算法中的编码方式来表示调度方案,同时为了提出的方法具有更强的全局搜索能力,运用克隆选择算法作为搜索引擎。最后,验证提出的方法的有效性,对7组Benchmark实例进行测试。实验结果表明,基于基因表达式的克隆选择算法在求解作业车间调度问题中是非常有效的。     

基于滚动时域优化的机场起降动态调度

为了减少作战时军用飞机实际起降时刻与计划起降时刻产生的偏差,提出一种基于滚动时域优化原理的动态机场起降调度策略,分析军用飞机起降过程中的时间窗口约束和尾流间隔约束。对进入每个预测窗口内的飞机队列,以加权提前/延误时间和最小作为目标函数,将军用飞机起降调度模型转换为带到达时间的单机加权E/T调度模型。设计一种针对自然数域的离散粒子群算法,并应用该算法进行模型求解。通过仿真实验确定了算法的参数,仿真结果说明了模型和算法的有效性。