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在高速计算机中,随着元器件的小型化,热通量增加了。此外,元器件的规定结温以及线路上相连的元器件之间的结温差一直在下降。随着电路速度的提高,这些因素变得越来越重要了。再者,为了达到允许的可靠性水平,必须限制元件的最高和最低温度。因此,高速计算机的传统冷却方法越来越不适用了,特别是对于高密度大功率元器件来说更是如此。热设计就成为提高电路速度和整个计算机性能的关键因素。目前,大多数电子组件和电子系统都用普通的强迫空气对流方法进行冷却。但是现在越 相似文献
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云计算和大数据时代对高密度存储服务器的需求越来越大。由于温度对电子元器件的性能和寿命有很大的影响,而高密度存储服务器的功率密度更大,故必须对其进行合理的热设计,以确保服务器工作时的温度在合理可控范围内。介绍了高密度存储服务器的结构,以及散热风道、散热器、风扇等关键散热部件的热设计方法。热设计整体方案采用吸风式的强迫风冷散热方式;基于Flotherm热仿真软件对整机系统进行了仿真优化;在35℃实际应用环境下对产品样机进行了热测试。测试结果表明,该热设计方案满足热设计要求。 相似文献
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徐丽媛 《电子制作.电脑维护与应用》2015,(4)
电子设备机箱中集成了大量的发热元器件,这些元器件的安装导致机箱内部高温。如果机箱散热不当,将造成箱内元器件热击穿、电参数变化和设备无法正常工作等多种问题。因此,解决电子设备机箱散热问题为各元器件的正常工作提供了良好的工作环境,而做好机箱散热结构设计则是上述工作的重要前提和保障。 相似文献
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夏天的炎热不仅让我们觉得难受,就连电脑如果不能很好地散热也会出现“中暑症”。随着CPU主频不断提高、高速硬盘普及、高性能显示卡频繁更新换代,机箱内部的散热问题因此也越来越受到人们重视。如果机箱散热设计不当就会造成热量无法及时排出,最终导致电脑无法正常运行甚至部分元器件损坏。如何才能让机箱内部通风顺畅,各种散热器工作搭配协调合理呢? 相似文献
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主轴系统的热误差是影响数控机床加工精度的重要因素。受自然界蜂巢分形结构的启发,设计了一种基于蜂巢仿生流道的主轴系统冷却结构,并建立了蜂巢仿生流道冷却结构模型。在数值传热学相关理论基础上,通过Fluent有限元软件对蜂巢仿生流道(单孔和多孔流道截面结构)和螺旋形流道冷却结构方案进行仿真计算,流固耦合分析结果显示两种前者流道结构比后者的流动特性较好,散热效果更好。在同等边界条件和冷却液体积相同情况下,多孔蜂巢形流道截面结构比单孔蜂巢形流道截面结构的散热效果更理想、温差更小。研究结果可以为主轴系统的冷却结构乃至电子元器件等微系统结构热设计提供参考。 相似文献
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介绍了使用Icepak热分析软件对大功率机箱进行热仿真和热设计,通过仿真数据对机箱所采取的散热措施进行对比分析,以获得一种较为合理的热设计形式,满足机箱散热的要求 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