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在大容量火力发电厂中,直流系统和交流不停电系统(UPS)是两个不可缺少的电源系统。简要介绍了某电厂直流系统和UPS系统电源的基本构成、主要特点和运行方式,并对直流系统和UPS系统在大型发电厂中的应用和重要性进行了阐述,进而探讨了直流系统和UPS系统的运行和维护。 相似文献
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针对如何建立企业的Internet信息平台系统,提出了基于Web和工作流技术的办公自动化系统设计方案.介绍了办公自动化系统的优点,讨论了系统的整体设计目标和在设计时要注意的问题,阐述了系统的整体结构和工作流平台系统的构成. 相似文献
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本文对藏文古籍著录的内容进行了具体的研究和分析,并对著录系统界面进行了设计和基本功能的实现。本系统包括了四个子系统,分别是书籍著录系统、铭刻著录系统、文书著录系统和讲唱著录系统。最后,本文详细介绍了书籍著录系统的设计和实现。 相似文献
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针对通信系统的效能评估提出了一种半实物仿真系统的设计及实现方式,综合分析了国外半实物仿真系统的发展状况和研究成果。提出了一种可行的半实物仿真系统的总体框架和系统组成,详述了半实物仿真系统中核心设备一节点云模拟器和电台半实物仿真设备的设计和实现思路,最后描述了以此半实物仿真系统为基础构建的通信系统效能评估系统,并给出系统所具备的测试能力。 相似文献
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基于Web和工作流技术的办公自动化系统 总被引:10,自引:1,他引:10
针对如何建立企业的Internet信息平台系统,提出了基于Web和工作流技术的办公自动化系统设计方案。介绍了办公自动化系统的优点,讨论了系统的整体设计目标和在设计时要注意的问题,阐述了系统的整体结构和工作流平台系统的构成。 相似文献
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高速铁路通信系统与传统公共移动通信系统在系统要求和应用环境方面都存在较大区别。分析了目前高速铁路通信系统建设方面所存在的关键问题和技术瓶颈,给出了该系统建设所需完成的特殊要求和任务,并介绍了目前正在实施和作为研究热点的系统方案和体系结构。 相似文献
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本文介绍了Hypertable系统的数据模型,阐述了系统的体系结构和表结构组成,分析了系统的工作原理,针对Hypertable系统和Bigtable系统存在的差异,进行对比分析。 相似文献
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基于自适应控制策略和Lyapumov稳定性理论,对一类非拓扑等价的Lorenz系统,Chen系统和Lu系统的同步控制问题进行了研究。通过构造适当的控制函数和设计参数的自适应控制律,实现了Lorenz系统与Chen系统,Lorenz系统与Lu系统的大范围渐近稳定同步,导出了两混沌系统同步的充分条件;数值仿真表明了该方法的有效性。 相似文献
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母晨光 《数字社区&智能家居》2009,(9X):7619-7620
该文针对当前计算机网络与通信系统之间存在的一些含混概念和问题,从系统观点分析了通信系统与计算机网络系统的功能分工和界定;然后从信息技术综合发展观点分析了通信系统与计算机网络系统进一步融合的趋势。并在其中提出了一些对计算机网络系统和通信系统融合的一些意见和看法。 相似文献
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《Ergonomics》2012,55(11):1330-1343
Changes in visual and oculomotor functions were tested in eight young volunteer subjects after performing a 3-D visually-guided task for 25min. The visual stimuli were given by using a head-mounted display. No significant change was detected in the AC/A ratio and the stereo-acuity. Changes were found in refraction and ocular convergence. Slight but significant hyperopic changes were detected in refraction after the task. The mean amplitude of convergence eye movement elicited by test Stimuli after the task was significantly changed in the pooled data. They were significantly reduced when the subjects were tested by the disparity step of 0.7°, but significantly increased when tested by the step of 6°. The mean amplitudes were not significantly changed after the task when the subjects were tested by the intermediate disparity steps of 1.5 and 3°. In data obtained for each subject, the amplitude of ocular convergence evoked by test stimuli after the task was reduced significantly in most subjects. In the majority of subjects, however, the results were not consistently significant when they were tested by step stimuli with different disparities. In only a few subjects, the changes were consistently significant except when the largest disparity was tested. On the other hand, the mean peak velocities of ocular convergence after the task were not significantly changed in the pooled data. In individual subjects, the changes of velocities of ocular convergence evoked by test stimuli after the task were more variable: they increased in some subjects but decreased in other subjects. Consequently, in only one subject, both amplitudes and peak velocities of ocular convergence tested by the-disparity steps of 0.7, 1.5 and 3° were consistently reduced after the task. The changes in refraction or ocular convergence found in this study were relatively small, and were not in the pathological range. The significance of these data are discussed. The results of the present study provide the basis for the more detailed analyses of the human factor in the head-mounted display. 相似文献
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在简要介绍顺序形态变换的基本概念及相关性质和对顺序形态变换进行边缘检测的原理进行阐述,以及对结构元素和百分位对边缘检测的影响进行讨论的基础上,根据图像形态学多刻度形态滤波的思想,从抑制噪声的角度对基本边缘检测算子进行推广和扩展,首先构造了3种边缘检测算子,并从理论上分析了算子的特性;然后将多结构元与图像边缘进行匹配,提出了3种广义顺序形态边缘检测算子并给出了一般表达形式;最后着重探讨了多结构元素及二重混合顺序形态变换百分位值p、q的选取原则.实验结果表明,该边缘检测算子在抑制噪声对图像边缘的影响和保持图像细节方面,优于传统的边缘检测算子和普通的形态边缘检测器. 相似文献
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《Ergonomics》2012,55(9):1400-1417
Two studies are reported which first observe, and then attempt to replicate, the cognitive demands of intensive care unit (ICU) activity whilst concurrently learning audible alarms. The first study, an observational study in an ICU ward, showed that the alarms are very frequent and co-occur with some activities more than others. The three most frequently observed activities observed in the ICU were drugs (calculation, preparation and administration), patient observation and talking. The cognitive demands of these activities were simulated in a second, laboratory-based experiment in which alarms were learned. The results showed that performance in the alarm task generally improved as participants were exposed to more repetitions of those alarms, but that performance decrements were observed in the secondary tasks, particularly when there were two or three of them. Some confusions between the alarms persisted to the end of the study despite prolonged exposure to the alarms, confusions which were likely caused by both acoustic and verbal labelling similarities. Practitioner Summary: The cognitive demands of working in an ICU were observed and simulated whilst alarms were learned. Alarms should generally avoid sharing similar rhythmic (and other) characteristics. The simulation task described here could be used for testing alarm learning without requiring a clinical environment. 相似文献
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以贵州开阳地区典型土壤为对象,研究了开阳地区土壤中硒元素的含量、分布及影响因素。结果表明,开阳地区土壤中硒的背景值高,其含量远高于全国土壤背景值;硒在土壤剖面上的分布存在空间差异,总体趋势是硒在表土层聚集;土壤中硒含量受土壤成土母质的控制。同时,表生地球化学作用、生物作用以及人类活动也深刻影响它们在土壤中的重新分配。 相似文献
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本文对甘肃景电灌区次生盐化土壤的理化性质进行了研究 .该区次生盐渍化土壤主要为硫酸盐氯化物和氯化物硫酸盐型 ,水溶性钠离子在阳离子中占绝对优势 .土壤通体碳酸钙含量很高 ,并有少量的石膏 .钠离子饱和度很高 ,具有钠质特性或钠质化现象 ,盐化与钠质化同时进行 .在此基础上对次生盐渍化的机理和改良进行了讨论 相似文献
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1.背景随着国际贸易的形成和发展,市场竞争环境变得持续多变和不可预测,如何快速响应市场、在最短的时间内开发出用户满意的新产品已成为企业共同追求的目标。动态联盟正是应运这一需求而提出的提高企业敏捷性的一种有效途径。动态联盟是指为了响应已经或即将出现的市场机遇,由若干个优势互补的企 相似文献
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文章介绍了生物免疫的免疫原理及入侵检测系统的原理,论述了免疫原理在入侵检测技术中的应用,着重讨论了阴性选择模型与危险理论及有关算法在入侵检测系统中的应用最后在分析入侵捡测方法存在问题的基础上,探讨了基于免疫原理的入侵检测系统的研究方向。 相似文献