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提出一个基于网格服务树的网格计算过程的表示模型。对网格服务、网格计算过程、网格服务树、网格给出了形式化的定义,描述了一个网格计算过程表示模型,并给出了实现的机制和算法,最后给出利用Webservice技术的模拟试验的方法。分析和实验结果表明,该模型有效地表示了基于WAN或Internet的网格计算过程,符合OGSA规范。该模型适合网格系统的构建、监测以厦基于Webservice机制的Internet的QoS管理等应用领域。 相似文献
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非凡的服务质量是网格的基本特征,基于QoS的网格任务调度问题已成为国内外研究的热点.由于网格环境的复杂性和用户主观判断的模糊性,传统基于QoS的网格调度算法不能处理具有多个模糊QoS需求的调度问题.用区间值模糊来描述用户的主观QoS需求信息,提出基于D-S理论的区间值模糊多QoS测量方法,对区间值模糊数表达的用户多QoS需求进行融合与处理,再将这些区间值模糊数QoS融合值作为任务的优先级加入到任务调度算法中,提出一种基于D-S理论的网格任务多匹配调度算法.研究结果和仿真实验表明,该算法不仅可以处理区间值模糊不确定性信息,在满足用户多QoS需求的情况下还可大大减小任务调度的时间跨度. 相似文献
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在深入研究网格环境下任务调度算法的基础上,提出一种基于QoS的协作型任务调度遗传算法并通过引入协作型任务的形式化描述DAG图构造了QoS参数模型.该参数模型提出了任务完成时间、价格和可靠性三个QoS参数并将这些QoS参数引入遗传算法,实现了网格环境下协作型任务调度对服务质量的优化并保证了协作型任务之间的数据依赖.通过与DAG-MIN和DAG-GSA算法的对比实验表明,该算法能在保证较优调度性能的同时大幅度提高调度的服务质量. 相似文献
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网格市场环境下,用户的服务质量(QoS)需求更加多样化;更多普通用户加入网格市场,难以提供精确的QoS需求信息.因此,基于用户模糊QoS需求的调度算法成为网格市场中研究的热点.多维QoS网格调度的形式化描述,利用模糊决策理论有效地将用户模糊的QoS需求的映射到网格资源,利用AHP算法确定用户关于多维QoS各维度之间的权重关系,给出一种模糊决策的多维QoS的调度方法.实验表明,模糊决策的多维QoS批调度算法在不需要用户提供精确的QoS参数前提下,有效满足用户QoS需求.与现有的QoS批调度方法相比,该算法具有较好的一次作业完成率,且作业完成率波动较小. 相似文献
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一种基于QoS的网格服务选择机制 总被引:1,自引:0,他引:1
开放网格服务体系结构OGSA提出了网格服务的概念,为网格资源的虚拟化管理给出了一条有效途径。当前网格系统对于网格服务的支持主要集中在服务的功能发现与调用部分,缺乏对服务的非功能属性的管理支持。服务的非功能属性如服务的响应时间、价格、可靠性等对于用户来说非常重要,体现着用户对网格服务的QoS需求。基于QoS的服务选择机制能够对网格服务的QoS模型进行管理和度量,对于用户提出的QoS需求,服务匹配算法能够为用户选择满足需求倾向的服务。 相似文献
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《Journal of Computer and System Sciences》2006,72(4):706-726
This paper is to solve efficient QoS based resource scheduling in computational grid. It defines a set of QoS dimensions with utility function for each dimensions, uses a market model for distributed optimization to maximize the global utility. The user specifies its requirement by a utility function. A utility function can be specified for each QoS dimension. In the grid, grid task agent acted as consumer pay for the grid resource and resource providers get profits from task agents. The task agent' utility can then be defined as a weighted sum of single-dimensional QoS utility function. QoS based grid resource scheduling optimization is decomposed to two subproblems: joint optimization of resource user and resource provider in grid market. An iterative multiple QoS scheduling algorithm that is used to perform optimal multiple QoS based resource scheduling. The grid users propose payment for the resource providers, while the resource providers set a price for each resource. The experiments show that optimal QoS based resource scheduling involves less overhead and leads to more efficient resource allocation than no optimal resource allocation. 相似文献
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This paper presents a cross-layer quality of service (QoS) optimization policy for computational grid. Efficient QoS management is critical for computational grid to meet heterogeneity and dynamics of resources and users’ requirements. There are different QoS metrics at different layers of computational grid. To improve perceived QoS by end users over computational grid, QoS supports can be addressed in different layers, including application layer, collective layer, fabric layer and so forth. The paper tackles cross-layer grid QoS optimization as optimization decomposition, each layer corresponds to a decomposed subproblem. The proposed policy produces an optimal set of grid resources, service compositions and user's payments at the fabric layer, collective layer and application layer respectively to maximize global grid QoS. The cross-layer optimization problem decomposes into three subproblems: grid resource allocation problem, service composing and user satisfaction degree maximization problem, all of which interact through the optimal variables for capacities of grid resources and service demand. In order to coordinate the subproblems, cross-layer QoS feedback mechanism is established to ensure different layer interactions. The simulations are conducted to validate the efficiency of the proposed policy. 相似文献
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在网格计算商业应用环境中,保障用户服务质量(QoS)需求和服务使用效益以及优化系统资源效能是一个重要环节.为保证服务供求双方QoS需求的均衡,提出了在QoS参数匹配时,对用户QoS期望值进行估算的方法.该方法根据效益原理,针对服务提供方的QoS能力,估算出一组均衡的QoS参数值,为服务选择提供依据,使用户能获得较高的服务使用效益.实例分析表明,该方法能可靠地估算出有效的QoS期望值. 相似文献
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Ad hoc grids are highly heterogeneous and dynamic, in which the availability of resources and tasks may change at any time.
The paper proposes a utility based resource selection scheme for QoS satisfaction and load balancing in ad hoc grid environments.
The proposed scheme intends to maximize the QoS satisfaction of ad hoc grid users and support load balancing of grid resources.
For each candidate ad hoc grid resource, the scheme obtains values from the computations of utility function for QoS satisfaction
and benefit maximization game for ad hoc grid resource preference. The utility function for QoS satisfaction computes the
utility value based on the satisfaction of QoS requirements of the grid user request. The benefit maximization game for grid
resource node preference computes the preference value from the resource point of view. Its main goal is to achieve load balancing
and decrease the number of resource selection failure. The utility value and the preference value of each candidate ad hoc
grid resource are combined to select the most suitable grid resource for ad hoc grid user request. In the simulation, the
performance evaluation of proposed algorithm for ad hoc grid is conducted. 相似文献
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针对类型多样的异构资源、动态协作的复杂网格环境,需要有效的服务质量(QoS)控制机制保障网格应用的需求,网格QoS需引入新的概念和机制,实现QoS需求的描述与映射、动态资源聚合与共享及任务间协作,灵活有效地进行网格应用流的聚合、区分和控制.在此基础上,介绍了网格QoS目前的研究情况,分析了网格QoS控制的特点、难点及其基本需求.结合实际研究,对网格QoS控制的关键技术——网格QoS管理、控制策略、资源预留、自适应控制、QoS协商进行了较深入的剖析,同时讨论了QoS评价的问题.最后总结了网格QoS的基本研究目标和未来的研究方向. 相似文献
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In this paper, we consider multiple QoS based grid resource scheduling. Each of grid task agent's diverse requirements is modeled as a quality of service (QoS) dimension, associated with each QoS dimension is a utility function that defines the benefit that is perceived by a user with respect to QoS choices in that dimension. The objective of multiple QoS based grid resource scheduling is to maximize the global utility of the scheduling system. 相似文献
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考虑网格应用QoS需求,以最大化网格系统的经济收益为目标,提出了一种基于贝叶斯策略的网格资源分配方法。该方法基于价格可代表资源QoS综合性能的思想,利用历史QoS匹配记录,运用朴素贝叶斯定理根据用户提交的价格参数来分配与其级别相对应的符合要价范围资源,并优先考虑QoS水平较高的任务,将当前时刻QoS水平较高的资源预留给下一时刻到达的QoS水平较高的任务,而忽略当前时刻QoS水平较低的任务。实验结果表明,该资源分配方法不仅能有效地保障用户QoS,而且能使网格系统获得较大的经济收益。 相似文献
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基于QoS的网格资源管理 总被引:15,自引:0,他引:15
资源管理是网格计算研究领域中的一项重要研究点,目前的研究工作大多致力于解决异构性问题,对于在交付无缝QoS(quality of service)前提下提高资源分配性能方面还缺乏深入的研究.而且,目前对网格QoS的研究集中于将多媒体网络QoS的相关成果融入网格体系架构中以提供对网格QoS的支持,而缺少对网格QoS的特性进行系统化的研究与归纳.为此,提出了网格QoS的层次结构模型,并对其中承上启下的虚拟组织层QoS参数进行了新的分类和测量;然后,利用SNAP(service negotiation and acquisition protocol)协议对基于网格QoS层次结构模型的网格QoS参数的映射转换过程进行了分析;最后,设计了网格资源管理仿真系统,并运用相关的网格QoS的研究改进了现有的Min-Min算法.仿真实验结果表明,基于QoS的网格资源管理可以在满足用户QoS需求下,有效地提高网格资源的利用率和服务请求的成功率. 相似文献
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How to guarantee user’s QoS (Quality of Service) demands become increasingly important in a service-oriented grid environment.
Current research on grid resource advance reservation, a well known and effective mechanism to guarantee QoS, fails to adapt
to dynamic behavior of grid, and cannot solve imprecise deny of reservation request problem efficiently. For this, enabling
system architecture for advance reservation is proposed. Virtual resource container (VRC) is adopted to alleviate a negative
effect resulted from dynamic behavior of grid and QoS deviation distance (QDD) based logical resource selection algorithm
is put forward to decrease imprecise reject ratio of reservation. At last, this new architecture is deployed to campus grid,
and two illustrative experiments are conducted. Experimental results show that system architecture for advance reservation
proposed in this paper can alleviate negative influence of grid resource dynamic fluctuation and avoid imprecise reject of
advance reservation request effectively. 相似文献