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《照明工程学报》2017,(6)
从视觉功效试验参数角度出发,分析USP、S、MOVE、MES2等中间视觉光度学模型计算结果的差异及成因,并讨论了各模型在隧道照明中的适用性。结果表明,在隧道中间段亮度水平范围内,四种中间视觉模型获得的亮度增益幅度为MOVEMES2SUSP。基于视觉功效的各中间视觉模型主要区别在于亮度适应系数x,有色差、高对比度和大偏心角的视觉任务会增大中间视觉函数Vm(λ)中暗视觉函数V'(λ)的权重;而无色差、低对比度和小偏心角的视觉任务会使得明视觉函数V(λ)的权重更大。隧道行车过程多为目标有色差、5°偏心角和包含正负对比度的视觉任务,MOVE模型更适用于评价隧道中间段的人眼实际感受。 相似文献
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光源色温对隧道及道路照明视觉功效影响的研究 总被引:3,自引:2,他引:1
根据国外相关研究成果和中间视觉理论,采用自行研制的反应时间测量系统和PR-650光谱扫描仪,分别对同类型不同色温的光源进行了反应时间和光谱能量分布测试。获得了在中间视觉条件下反应时间与背景亮度之间的函数表达式,以及反应时间随背景亮度、视标对比度和视标偏心角改变的变化规律。结果表明,在所研究的背景亮度范围内,用高色温的紧凑型荧光灯照明能缩短反应时间,从而增快对瞬态事件的反应速度;反之,用低色温的紧凑型荧光灯照明则会延长反应时间,导致大脑反应迟钝。本研究成果提供了光源色温影响视觉功效的实验依据,为制定更加科学和合理的隧道及道路照明设计标准打下了基础。 相似文献
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中间视觉光度学一直为国际照明界所关注,CIE191∶2010推荐了基于视觉功能的中间视觉光度学系统。本文论述了USP模型、MOVE模型、MES1模型和MES2模型的研究背景、实验条件以及各自的特点和适用范围。通过对不同S/P值光源的理论分析和实际测量,发现在中间视觉的低亮度区域USP模型精度最高,在高亮度区域MES2模型精度最高,因此应根据具体的视觉任务选择合适的模型以达到最高的测量精度,对于采用迭代方法计算光度量的中间视觉模型,还应保证亮度适应系数不能为负。此外,在中间视觉区域,能量主要集中在短波段的光源比能量主要集中在长波段的光源具有更高的发光效能,如果采用明视觉模型评价中间视觉照明质量,将导致错误的结果。 相似文献
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传统的图像镜像对称性度量方法受物体几何形状背景和图像对比度影响较大,度量结果往往不够准确.针对以上缺陷,本文提出了一种新的镜像对称性度量方法.由于采用最优阈值分割,本方法受亮度、对比度和噪声的影响小,有良好的鲁棒性;它充分利用图像中物体的灰度信息,不受背景和物体几何形状的影响,对镜像对称性很敏感.实验结果证明,对于不同亮度、对比度以及含噪声的图像,本方法均能准确完成物体的镜像对称性度量. 相似文献
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Expert system (ES) theory problems have been traditionally considered without any essential connection with common control problems. However, nowadays, because of progress in ES theory development in practice and because of its wide use for solving complex control problems, new items in this field of research are being stressed, many of which are connected with traditional automation control. The combined study of adaptation and ES problems makes it possible to draw significant practical conclusions for systems of both types. In this work an analysis of general problems and of possible approaches to solving them in some special types of ESs based on Bayes inference is carried out. The main attention is focused on such ES characteristics as: (i) inference stability (with respect to variations in probabilistic approximation measures of rule truth); (ii) knowledge base adaptation (rule modification and new rule creation or approximation measure rule tranformation); (iii) knowledge base consistency maintenance. 相似文献
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Two alternative approaches to the solution of control problems under conditions of uncertainty are considered: (i) synthesis of adaptive systems; (ii) synthesis of robust systems. Non-stochastic (set) models of uncertainty are used. An estimate of the quality of the plant parameter identification is given by evaluating the diameter of the set to which the parameter vector belongs. The obtained non-improvable set estimates of the parameters (in the form of ellipsoids or convex polyhedra) are the boundary determining the expediency of the change-over to the construction of robust control systems. The remaining part of the paper is devoted to the solution of the problem of synthesis of discrete robust control systems. The necessary and sufficient conditions of robust stability proposed by the author are used and are efficiently tested by means of a special software package ‘Robust stability’ for IBM-type personal computers. 相似文献
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针对变压器状态智能识别方法泛化能力不足的问题,提出一种基于领域自适应的变压器状态识别方法。首先,使用多尺度时频分析方法挖掘变压器振动信号中的状态信息和固有属性,构建完备的变压器状态描述特征空间;然后,使用一种基于流形嵌入和动态分布对齐的领域自适应方法,以减少领域偏移带来的负面影响,并且动态评估和量化流形特征的边缘分布和条件分布;最后,基于结构风险最小化原则迭代训练得到变压器状态识别分类器。测试结果表明所提方法在一定程度上改善了变压器状态识别分类器泛化能力低的问题。 相似文献
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自适应技术在电力系统继电保护中应用 总被引:2,自引:0,他引:2
在概述国内外自适应技术在继电保护应用的基础上,提出了今后自适应继电保护的主要研究方向。利用通信网络更加灵活地获取和应用故障信息,将人工智能技术应用于故障信息处理,继电保护装置有望获得更强的自适应能力,从而显著提高其动作性能。 相似文献
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Fransson P.A. Johansson R. Tjernstrom F. Magnusson M. 《IEEE engineering in medicine and biology magazine》2003,22(2):53-57
There are several modes of adaptation to postural perturbations used to withstand balance disturbances and reduce the effects of muscle fatigue. We summarize experimental results, which demonstrate that there are several modes of adaptation to postural perturbations, and we discuss the properties of these adaptive processes. The presented findings suggest that patients with balance disorders would benefit from rehabilitation programs that include a mixture of exercises aimed at training specific motor tasks or motor programs. 相似文献
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以Verschueren的顺应理论下的交际语境顺应理论为指导,就日常中西方跨文化交际过程中经常出现的跨文化交际语用失误的问题进行阐释,并提出成功的跨文化交际应该是交际双方彼此对对方交际语境的顺应. 相似文献
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Ways to develop and improve traction power-supply systems and adapt them for high-speed highways are considered. One way to improve a traction power-supply system and make it more efficient is to increase the nominal voltage in the dc traction network up to 24 kV. This allows one to increase the throughput and carrying capacities of railways, increase the distance between substations, reduce the cross section of traction-network wires, and significantly reduce power losses in power-supply facilities. All this, alongside the absence of unbalanced supply voltage and inductive losses, as well as a significantly lower electromagnetic action on the infrastructure under dc conditions, results in a greater efficiency than in the case of any alternating- current traction power systems of alternating current. A mathematical model of dynamic electromagnetic processes in electrical circuits with semiconductor converters is fleshed out. Analysis and synthesis of electromagnetic processes and the main characteristics of multipulse converters, as well as a comprehensive technical and economic comparison, shows that 24-pulse rectifying circuits with a serial connection of threephase bridge are most efficient for these systems. These rectifiers provide an improvement in the quality of electrical energy not only for the primary power-supply system, but also for the traction network. They allow one to use simpler and more economical active-passive smoothing filters that provide the electromagnetic compatibility (EMC) of a new traction dc power system with the communication and railway automation facilities. In addition, the use of 24-pulse rectifiers can allow one to significantly reduce the consumption of reactive energy, reduce power losses in a traction network, and increase the efficiency of traction substations. 相似文献