共查询到20条相似文献,搜索用时 62 毫秒
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针对当前的虚拟化技术无法使各个虚拟机平等地或按特定比例地共享磁盘带宽、无法保证虚拟机间的I/O性能隔离的问题,基于Xen半虚拟化技术中的块IO请求处理过程,提出一种适用于Xen虚拟机间的磁盘I/O性能隔离算法-XIOS(XenI/O Scheduler)算法,在通用块层调度各虚拟机的块IO操作(bio结构),在I/O调度层保障延迟需求.实验结果表明该算法有效地在虚拟机间按比例地分配磁盘带宽. 相似文献
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基于Xen的虚拟磁盘调度算法改进 总被引:1,自引:0,他引:1
Xen目前所采用的I/O调度算法能够较好的保证公平性;但在实际应用中,不同的虚拟机可能有不同的性能需求。该文研究了Xen虚拟存储的实现和I/O调度算法的原理,提出了基于反馈的动态优先级调度策略,通过对比测试验证了磁盘带宽在不同虚拟机之间的按需分配。 相似文献
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刘硕 《电脑与微电子技术》2014,(5):30-32,44
研究表明,好的磁盘调度算法可以明显优化磁盘的I/O性能,Linux提供四种调度算法可供选择。基于Linux 2.6.32内核源码,研究Noop、Deadline、Anticipatory、CFQ四种磁盘调度算法的基本原理和特点,分析每种算法的优缺点,这对系统管理员针对不同类型的应用场景来调整优化I/O调度算法有着重要意义。 相似文献
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介绍应用于RAID控制器的I/O调度算法的设计与实现.主要目标是把来自RAID模块针对每个磁盘的具体读写请求按照响应的策略放入对应磁盘的读写I/O队列.然后根据具体请求的优先级和读写特性,对响应请求在队列中的次序进行调整或者对前后项进行合并,实现I/O请求的调度策略. 相似文献
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提出一种新的基于模糊逻辑的VBR视频流接纳控制算法。该算法通过对调度周期的在线调整,使得系统所剩的磁盘I/O带宽和缓存空间达到一种等量的动态平衡,从而大大提高了系统资源的综合利用率。仿真结果表明,该算法下的接纳率比最优固定周期算法下的接纳率提高了约25%;同时,也比前人提出的动态调度周期算法的接纳率提高8%,并且算法的可行性也得到明显增强。 相似文献
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一种动态优先级排序的虚拟机I/O调度算法 总被引:1,自引:0,他引:1
I/O任务调度是影响I/O密集型虚拟机性能的重要因素。现有调度方法主要是针对虚拟机整机I/O带宽的优化,较少兼顾各虚拟域与全局性能,也无法满足域间差异化服务的要求。针对现有方法的不足,提出了一种动态优先级排序的虚拟机I/O调度算法DPS。该算法基于多属性决策理论,以离差最大化方法计算I/O任务的优先级评估属性权重,对I/O任务优先级进行综合评估;通过引入任务所在虚拟域价值,体现云计算环境下虚拟域重要性差异。在Xen系统中通过实验评测DPS调度虚拟化网卡的性能,结果表明,DPS能够有效提高指定域与全局的I/O任务截止期保证率、整机I/O带宽,并能为不同虚拟域的I/O应用提供差异化服务。 相似文献
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流媒体缓存的自适应统计窗缓存算法 总被引:2,自引:1,他引:1
网络带宽和磁盘I/O带宽是视频点播系统的两大瓶颈.为了缓解磁盘I/O带宽问题,本文引入统计窗概念.提出自适应统计窗缓存算法,采用周期性缓存决策方法管理缓存的流媒体数据,同时采用区分优先级缓存策略和冗余释放策略提高算法性能.采用实际点播数据进行的仿真研究表明:自适应统计窗缓存算法的性能优于定长分段、指数分段和自适应分段算法,特别是在VCR操作时,本算法的性能更佳. 相似文献
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S. Shaw 《Journal of Computer Assisted Learning》1993,9(2):93-99
Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained. 相似文献
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European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven. 相似文献
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融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。 相似文献
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Wayne O’Brien Author Vitae 《Journal of Systems and Software》2008,81(11):1997-2013
Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them. 相似文献
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This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives. 相似文献
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Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what
is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic
sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and
its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of
an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify
robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can
or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
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David Poole 《Computational Intelligence》1989,5(2):97-110
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given. 相似文献
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Watts S. Humphrey 《Annals of Software Engineering》2002,14(1-4):39-72
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical. 相似文献
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基于复小波噪声方差显著修正的SAR图像去噪 总被引:4,自引:1,他引:3
提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。 相似文献
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R. NOSS 《Journal of Computer Assisted Learning》1987,3(1):2-12
Abstract This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development. 相似文献