网格计算中任务调度算法的仿真研究

研究网格计算中任务调度优化问题,由于网格环境具有动态性、异构性等特点,对高效调试资源效率有影响,导致传统网格任务调度算法收敛速度慢、局部最优等缺陷,使网格任务调度效率低.为了提高网格任务调度效率,提出一种基于粒子群算法的任务调度模型.模型根据任务调度原理和粒子群算法特点,建立了网格任务调度的元任务模型和性能指标的数学模型,然后采用粒子群算法对该模型进行求解,提高资源利用率和任务执行效率.仿真结果表明,根据粒子群算法的任务调度策略,提高了任务调度的速度和效率,很好的解决网格任务调度中存在的难题.     

基于微粒群算法的服务网格任务优化调度问题的研究

需要人参与提供服务的网格任务调度中,需要考虑许多时间因素。因此本文提出一个基于时间差异的网格任务调度模型,应用微粒群算法对网格中任务调度模型作性能优化,并通过分析和模拟,得出此算法能够得到任务调度的最优完成时间。     

基于动态粒子群优化的网格任务调度算法*

提出了一种基于动态粒子群优化的网格任务调度算法。设计了网格任务调度问题的数学模型,给出了自适应变异的动态粒子群优化算法的框架,引入了自适应学习因子和自适应变异策略,从而使算法具有动态自适应性,能够较容易地跳出局部最优。实验结果表明,本文算法能有效地解决异构网格任务调度问题,具有较好的应用价值。     

基于蚂蚁算法的网格任务调度研究

在多目标的任务条件下,网格任务调度不仅要完成多目标的优化工作,还要提升蚂蚁算法的资源利用率。基于蚂蚁算法的网格任务调度,属于集群计算机处理系统,其中每个数据库分布节点都有着较高的独立性。本文主要对基于蚂蚁算法的网格任务调度进行研究,通过分析蚂蚁算法的改进策略,得出蚂蚁算法的网格任务调度的有效性与仿真结果。     

一种快速网格任务调度策略

网格任务调度目标有很多,如用户要求任务轮转时间短、花费代价小,而资源提供者希望资源利用率高等,这些目标相互冲突,因此网格任务调度不仅是一个NP难问题,而且是一个多目标优化问题.本文根据网格环境下任务的时间相关性特点,对传统蚁群算法进行了改进,提出了一种快速网格任务调度算法.该算法不仅解决了网格调度中多目标优化问题,而且依据任务调度历史信息生成蚁群算法的初始信息素分布,提高了蚁群算法的求解速度.     

基于网格的任务调度与资源分配有效机制的研究

为实现QoS路由技术,提高网格的服务质量,本文定义了网格服务中任务调度的通信开销,给出了QoS路由树的生成原则,提出网格堆排序算法和QoS路由选择算法,利用算法实现了网格的任务调度与分配机制的设计.实验证明本设计能提高网格资源管理的效率.     

基于GRIDSIM的网格调度Min-Min算法改进研究

本文中的网格任务调度算法是在研究异构工作流系统基于OGSA网格协同任务调度的过程中,根据网格环境中资源的可用度,在特定的相依性网格任务环境下,对经典Min—Min算法进行了部分改进,提出基于资源可用度和任务相关性的相依性网格任务映射启发式算法。在作者所设计的层次网格任务调度器中得到了较好的调度效果和调度服务质量。     

安全和自适应备份的网格任务调度

现有的跨自治域网格任务调度算法均使用固定数目的任务备份来提高任务调度的成功率和容错性,无法适应网格环境动态性的特点.提出了三种基于自适应备份数并考虑网格安全因素的任务调度算法,分别为简单自适应备份算法、最高百分之K备份算法和懒惰备份算法.自适应备份算法根据整个网格系统的安全状况,自适应调整需备份的任务及任务备份数,并对失败的任务重新调度.仿真结果表明,基于自适应备份的网格任务调度算法可以有效提高不安全网格环境下的任务调度成功率,具有很好的容错性和可扩展性,优于固定备份数的任务调度算法.     

自适应邻域的多目标网格任务调度算法研究

针对网格计算中的多目标网格任务调度问题,提出了一种基于自适应邻域的多目标网格任务调度算法。该算法通过求解多个网格任务调度目标函数的非劣解集,采用自适应邻域的方法来保持网格任务调度多目标解集的分布性,尝试解决网格任务调度中多目标协同优化问题。实验结果证明,该算法能够有效地平衡时间维度和费用维度目标,提高了资源的利用率和任务的执行效率,与Min-min和Max-min算法相比具有较好的性能。     

基于网格资源超图模型的可信任务调度

网格任务调度是当前重要的研究领域。网格环境具有动态性、异构性等特点,网格资源的处理性能和稳定性都是影响到任务调度顺利完成的重要因素。为了获得更小的任务完成时间,该文根据网格环境的特点,建立了网格资源超图模型,在该模型基础上对资源按性能进行聚类,并提出一种可信任务调度算法GRHTS。模拟实验结果表明,该基于网格资源超图模型的可信任务调度算法优于同类算法,是一种有效的网格任务调度算法。     

Trusted dynamic level scheduling based on Bayes trust model

A kind of trust mechanism-based task scheduling model was presented. Referring to the trust relationship models of social persons, trust relationship is built among Grid nodes, and the trustworthiness of nodes is evaluated by utilizing the Bayes method. Integrating the trustworthiness of nodes into a Dynamic Level Scheduling (DLS) algorithm, the Trust-Dynamic Level Scheduling (Trust-DLS) algorithm is proposed. Theoretical analysis and simulations prove that the Trust-DLS algorithm can efficiently meet the requirement of Grid tasks in trust, sacrificing fewer time costs, and assuring the execution of tasks in a security way in Grid environment.     

网格环境下基于信任模型的动态级调度

网格用户、资源和服务的不确定性潜在地影响网格应用任务的正常执行,这样使得设计既能减小应用任务执行时间又能减小欺骗可能性的调度算法十分困难．参考社会学的人际关系信任模型,建立网格节点信任推荐机制,并利用D-S理论对推荐证据进行综合分析,从而定义出基于不确定性推理理论的信任度计算函数．将该函数并入DLS算法得到“可信”动态级调度算法(TDLS),从而在计算调度级别时考虑网格节点的可信程度．仿真结果证实,提出的TDLS算法以小的时间花费为代价,能有效提高任务在信任方面的服务质量需求．     

基于动态有色Petri网的网格服务工作流模型的研究

在深入了解网格技术、网格服务和网格工作流的概念、特点及其应用的基础上,提出了一种可行的网格服务工作流系统模型,重点介绍了动态优化建模技术、动态调度算法的实现思想.定义了一种动态有色Petri网作为服务工作流的建模工具,支持服务工作流的动态优化建模和动态调度,并为服务工作流模型提供性能评价依据.验证表明采用该模型能够很好地满足用户的QoS要求,并且有助于提高资源利用率.     

一种改进的启发式网格任务调度算法

网格任务调度算法是影响网格成功与否的关键技术之一。网格计算中,一个好的任务调度算法不但要考虑所有任务的makespan,使其值尽量小,同样要考虑到整个系统机器间的负载平衡问题。文章对异构计算环境下的元任务调度算法进行了分析,针对Min-min算法可能引发的负载不平衡问题,结合网格计算环境的特点,提出了一种适用于网格计算环境中的任务调度算法。     

一种基于人工免疫的新的网格资源调度算法

由于广域网性能的巨大提高和功能强大且价格低廉的计算机不断增多,网格计算以一种极具有前途和吸引力的新范式出现。网格计算是集成地理位置分布,异构,多领域资源的一种平台,它提供透明、安全、同等、高性能资源共享。要获取计算网格中潜在的能量,设计一种有效和高效的网格资源调度算法很重要。网格独特的特点使得网格环境下的资源调度是相当复杂的。本文将重点设计一种新的基于免疫算法的网格资源调度算法。     

基于SGE的仿真网格及其作业调度研究

网格引擎是一个构建本地和集群网格的工具,其框架是由四种类型的主机及其对应的守护进程构成.该文主要研究了通过SGE框架构建分布式仿真网格平台的方法,描述了仿真网格平台上执行用户提交的仿真任务的工作流程.随后讨论了基于SGE仿真网格中的资源组织和作业调度,并分析了仿真网格中所使用的作业调度算法,包括确定作业顺序的FIFO算法、优先级算法、等额度和日历算法等;确定队列顺序的负载调整、队列号等算法等.     

Security Driven Scheduling Model for Computational Grid Using NSGA-II

Number of software applications demands various levels of security at the time of scheduling in Computational Grid. Grid may offer these securities but may result in the performance degradation due to overhead in offering the desired security. Scheduling performance in a Grid is affected by the heterogeneities of security and computational power of resources. Customized Genetic Algorithms have been effectively used for solving complex optimization problems (NP Hard) and various heuristics have been suggested for solving Multi-objective optimization problems. In this paper a security driven, elitist non-dominated sorting genetic algorithm, Optimal Security with Optimal Overhead Scheduling (OSO₂S), based on NSGA-II, is proposed. The model considers dual objectives of minimizing the security overhead and maximizing the total security achieved. Simulation results exhibit that the proposed algorithm delivers improved makespan and lesser security overhead in comparison to other such algorithms viz. MinMin, MaxMin, SPMinMin, SPMaxMin and SDSG.     

EMPEROR: An OGSA Grid Meta-Scheduler Based on Dynamic Resource Predictions

Scheduling constitutes an integral feature of Grid computing infrastructures, being also a key to realizing several of the Grid promises. In particular, scheduling can maximize the resources available to end users, accelerate the execution of jobs, while also supporting scalable and autonomic management of the resources comprising a Grid. Grid scheduling functionality hinges on middleware components called meta-schedulers, which undertake to automatically distribute jobs across the dispersed heterogeneous resources of a Grid. In this paper we present the design and implementation of a Grid meta-scheduler, which we call EMPEROR. EMPEROR provides a framework for implementing scheduling algorithms based on performance criteria. In implementing a particular instantiation of this framework, we have devised models for predicting host load and memory resources, and accordingly for estimating the running time of a task. These models hinge on time series analysis techniques and take into account results of the cluster computing literature. Apart from incorporating these models, EMPEROR provides fully fledged Grid scheduling functionality, which complies with OGSA standards as the later are reflected in the Globus toolkit. Specifically, EMPEROR interfaces to Globus middleware services (i.e., GSI, MDS, GRAM) towards discovering resources, implementing the scheduling algorithm and ultimately submitting jobs to local scheduling systems. By and large, EMPEROR is one of the few standards based meta-schedulers making use of dynamic scheduling information.     

Simultaneous Scheduling of Replication and Computation for Data-Intensive Applications on the Grid

Managing large datasets has become one major application of Grids. Life science applications usually manage large databases that should be replicated to scale applications. The growing number of users and the simple access to Internet-based application has stressed Grid middleware. Such environment are thus asked to manage data and schedule computation tasks at the same time. These two important operations have to be tightly coupled. This paper presents an algorithm (Scheduling and Replication Algorithm, SRA) that combines data management and scheduling using a steady-state approach. Using a model of the platform, the number of requests as well as their distribution, the number and size of databases, we define a linear program to satisfy all the constraints at every level of the platform in steady-state. The solution of this linear program will give us a placement for the databases on the servers as well as providing, for each kind of job, the server on which they should be executed. Our theoretical results are validated using simulation and logs from a large life science application. This work was supported in part by the ACI GRID and Grid5000 projects of the French Department of Research.     

An Adaptive Scheduler for Grids

The recent development of telecommunication infra-structures such as the world-wide networks, interconnecting millions of computers spread all over the world, has made possible the coordinated use of a large amount of heterogeneous, weakly connected computational resources. This new area, known as Grid computing, is currently the focus of several research activities and projects. However, as in every new domain of research, in this one there are many unsolved questions, in particular those related to the management of the processing load inside the system. In this work, the problem of balancing processing loads on a Grid is approached by the introduction of the Generational Scheduling with Task Replication (GSTR) algorithm. A comprehensive set of simulations and tests is carried out in order to validate the proposed solution. A methodology for calculating and analyzing speed-up and efficiency ratios on heterogeneous groups of computers is also shown.