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871.
《Expert systems with applications》2014,41(6):2824-2831
Evaluation of the competitiveness of high-tech industry is a technical decision-making issue involving multiple criteria. It is also a practical path to promote a country’s competitiveness. However, the competitiveness indicators in high-tech industry often act and react upon one another. Moreover, different dimensions and indicator weights also affect the evaluation results. In this paper, the Mahalanobis distance is used to improve the traditional technique for order preference by similarity to ideal solution (TOPSIS). The improved TOPSIS method has the following properties: (1) an improved relative closeness which is invariant after non-singular linear transformation, and (2) the weighted Mahalanobis distance is the same as the weighted Euclidean distance when the indicators are uncorrelated. The new method is applied to evaluate the competitiveness of the Chinese high-tech industry using data from 2011. Consideration of the correlation between indicators improves the evaluation results (in terms of sorting and closeness) to a certain extent compared to the traditional TOPSIS method. The top five provinces are: Guangdong, Jiangsu, Shanghai, Beijing, and Shandong. This finding reflects the practical linkage among provinces and softens the closeness value, consistent with reality. 相似文献
872.
Previous research on perceiving spatial layout has found that people often exhibit normative biases in their perception of the environment. For instance, slant is typically overestimated and distance is usually underestimated. Surprisingly, however, the perception of height has rarely been studied. The present experiments examined the perception of height when viewed from the top (e.g., looking down) or from the bottom (e.g., looking up). Multiple measures were adapted from previous studies of horizontal extents to assess the perception of height. Across all of the measures, a large, consistent bias was found: Vertical distances were greatly overestimated, especially from the top. Secondary findings suggest that the overestimation of distance and size that occurs when looking down from a high place correlates with reports of trait- and state-level fear of heights, suggesting that height overestimation may be due, in part, to fear. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
873.
肝部阴影是肝癌的重要疑似对象,因此检测肝癌可以先将肝部阴影检测出来.但肝部阴影与正常肝组织密度接近,很难分割.为此,提出一种CV分割方法的初始距离函数的设置方法,该方法使初始曲线一开始就接近图像的分割边缘,极大地减少了CV方法的迭代次数,加快了CV方法目标提取的速度.最后将该方法应用于肝部阴影的精确检测,成功地分割了图像中的肝部组织与其中的阴影部分. 相似文献
874.
Linkenauger Sally A.; Witt Jessica K.; Stefanucci Jeanine K.; Bakdash Jonathan Z.; Proffitt Dennis R. 《Canadian Metallurgical Quarterly》2009,35(6):1649
Previous research has suggested that perceived distances are scaled by the action capabilities of the body. The present studies showed that when “reachability” is constrained due to a difficult grasp required to pick up an object, perceived distance to the object increases. Participants estimated the distances to tools with handle orientations that made them either easy or difficult to grasp with their dominant and nondominant hands. Right-handed participants perceived tools that were more difficult to grasp to be farther away than tools that were easier to grasp. However, perceived distance did not differ in left-handed participants. These studies suggest that, when reaching toward a target, the distance to that target is scaled in terms of how far one can effectively reach, given the type of reaching posture that is executed. Furthermore, this effect is modulated by handedness. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
875.
A novel fault diagnosis method of bearing based on improved fuzzy ARTMAP and modified distance discriminant technique 总被引:1,自引:0,他引:1
Zengbing Xu Jianping Xuan Tielin Shi Bo Wu Youmin Hu 《Expert systems with applications》2009,36(9):11801-11807
This paper presents a novel intelligent diagnosis method based on multiple domain features, modified distance discrimination technique and improved fuzzy ARTMAP (IFAM). The method consists of three steps. To begin with, time-domain, frequency-domain and wavelet grey moments are extracted from the raw vibration signals to demonstrate the fault-related information. Then through the modified distance discrimination technique some salient features are selected from the original feature set. Finally, the optimal feature set is input into the IFAM incorporated with similarity based on the Yu’s norm in the classification phase to identify the different fault categories. The proposed method is applied to the fault diagnosis of rolling element bearing, and the test results show that the IFAM identify the fault categories of rolling element bearing more accurately and has a better diagnosis performance compared to the FAM. Furthermore, by the application of the bootstrap method to the diagnosis results it can testify that the IFAM has more capacity of reliability and robustness. 相似文献
876.
两点源诱偏是对抗反辐射导弹(ARM)的一种有效的手段。首先采用数学方法研究了两点源诱偏反辐射导弹的原理,讨论了两点源诱偏作用下被动雷达导引头的瞄准方向,给出了两点源诱骗反辐射导弹的脱靶距离模型和案例分析,为研究靶场诱偏系统的试验方法和使用原则奠定了基础。 相似文献
877.
针对目前国内LED强光手电筒标准缺失的问题,本文参考美国手电筒标准ANSI/NEMA FL 1-2009Flashlight Standard,结合LED强光手电筒产品的自身特点,对LED强光手电筒的光线射程测试方法进行研究。主要对LED强光手电筒光程的测试原理、过程、测试难点进行分析,最后通过分析各种不确定度来源,给出了该方法的测量不确定度评定。 相似文献
878.
为更深入地在微观角度上研究变压器绝缘纸老化机理,利用分子动力学仿真,对不同温度下纤维素无定形区的热力学性质进行了研究。结果表明:纤维素无定形区为各向同性弹性材料,其弹性系数和各模量随着模拟温度的升高均有减小的趋势,与晶区相比,温度对其影响较大;无定形区的刚性随温度升高出现较大减弱;随着温度升高,无定形区内氢键数量减少,并且分子内氢键数目较分子间氢键数目下降快。对比晶区内的氢键数目在相同模拟温度下的极小变化,可知纤维素的老化首先是从纤维素的无定形区内分子间的氢键被破坏开始的。随模拟温度的升高,纤维素分子链运动加剧,但其末端距无明显变化。温度对纤维素无定形区的力学性质和氢键的影响从分子层次上阐明了纤维素绝缘老化实验中结晶度升高及无不定形区先行老化的微观机理。 相似文献
879.
Xi Yu Michael J Hounslow Gavin K Reynolds 《American Institute of Chemical Engineers》2015,61(8):2394-2402
Implementation of a Monte Carlo simulation for the solution of population balance equations (PBEs) requires choice of initial sample number (N0), number of replicates (M), and number of bins for probability distribution reconstruction (n). It is found that Squared Hellinger Distance, H2, is a useful measurement of the accuracy of Monte Carlo (MC) simulation, and can be related directly to N0, M, and n. Asymptotic approximations of H2 are deduced and tested for both one‐dimensional (1‐D) and 2‐D PBEs with coalescence. The central processing unit (CPU) cost, C, is found in a power‐law relationship, , with the CPU cost index, b, indicating the weighting of N0 in the total CPU cost. n must be chosen to balance accuracy and resolution. For fixed n, M × N0 determines the accuracy of MC prediction; if b > 1, then the optimal solution strategy uses multiple replications and small sample size. Conversely, if 0 < b < 1, one replicate and a large initial sample size is preferred. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2394–2402, 2015 相似文献
880.
有源重要用户供电风险评估方法研究 总被引:1,自引:0,他引:1
为切实保障有源重要用户的利益,挖掘供电过程中可能诱发用户安全、优质性和效益这3个方面需求不被满足从而产生风险的供电风险因素,归纳分类形成供电风险元。基于风险元传递思想,利用梯形相似模糊数建立了供电风险与用户需求风险之间的映射关系,定义了期望值函数使模糊数精确化,通过专家意见得到用户需求风险指标下的风险评估矩阵。考虑到用户需求风险指标之间具有很高的相关度,采用马氏距离代替传统的欧式距离求解每个供电风险元与正负理想解之间的距离,计算出每个风险元的风险值,根据TOPSIS思想对供电风险元威胁大小进行排序,排序结果可以很好地帮助供电公司辨识重要风险,制定规避策略。最后通过对比分析证明了所提方法的科学性和合理性。 相似文献