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Shaking-moment balancing of mechanisms with principal vectors and momentum

V. van der WIJK

《机械工程前沿（英文）》 2013年第8卷第1期页码 10-16 doi: 10.1007/s11465-013-0359-2

摘要：

The design of shaking-moment-balanced linkages still is challenging. Considering moment balance in the very beginning of the design process of mechanisms is important for finding applicable solutions. For this purpose, the method of principal vectors is investigated, showing a compact notation of the angular momentum with respect to the center of mass. The moment balance conditions are derived for three elements in series from which balance solutions are synthesized and illustrated. From the application for moment balancing of a 4R four-bar linkage it is shown that the moment balancing of closed kinematic chains remains challenging.

关键词： shaking-moment balancing principal vector linkage angular momentum

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Determination of the principal factors of river water quality through cluster analysis method and its

Liang GUO, Ying ZHAO, Peng WANG

《环境科学与工程前沿（英文）》 2012年第6卷第2期页码 238-245 doi: 10.1007/s11783-011-0382-7

摘要： In this paper, an artificial neural network model was built to predict the Chemical Oxygen Demand (COD ) measured by permanganate index in Songhua River. To enhance the prediction accuracy, principal factors were determined through the analysis of the weight relation between influencing factors and forecasting object using cluster analysis method, which optimized the topological structure of the prediction model input items of the artificial neural network. It was shown that application of the principal factors in water quality prediction model can improve its forecasting skill significantly through the comparison between results of prediction by artificial neural network and the measurements of the COD . This methodology is also applicable to various water quality prediction targets of other water bodies and it is valuable for theoretical study and practical application.

关键词： water quality forecast principal factor cluster analysis method artificial neural network

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Non-negativematrix factorization based unmixing for principal component transformed hyperspectral data

Xiu-rui GENG,Lu-yan JI,Kang SUN

《信息与电子工程前沿（英文）》 2016年第17卷第5期页码 403-412 doi: 10.1631/FITEE.1600028

摘要： Non-negative matrix factorization (NMF) has been widely used in mixture analysis for hyperspectral remote sensing. When used for spectral unmixing analysis, however, it has two main shortcomings: (1) since the dimensionality of hyperspectral data is usually very large, NMF tends to suffer from large computational complexity for the popular multiplicative iteration rule; (2) NMF is sensitive to noise (outliers), and thus the corrupted data will make the results of NMF meaningless. Although principal component analysis (PCA) can be used to mitigate these two problems, the transformed data will contain negative numbers, hindering the direct use of the multiplicative iteration rule of NMF. In this paper, we analyze the impact of PCA on NMF, and find that multiplicative NMF can also be applicable to data after principal component transformation. Based on this conclusion, we present a method to perform NMF in the principal component space, named ‘principal component NMF’ (PCNMF). Experimental results show that PCNMF is both accurate and time-saving.

关键词： Non-negative matrix factorization (NMF) Principal component analysis (PCA) Endmember Hyperspectral

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optimization of cutting parameters in high-speed milling based on grey relational analysis coupled with principal

Tao FU, Jibin ZHAO, Weijun LIU

《机械工程前沿（英文）》 2012年第7卷第4期页码 445-452 doi: 10.1007/s11465-012-0338-z

摘要：

This paper investigates optimization problem of the cutting parameters in high-speed milling on NAK80 mold steel. An experiment based on the technology of Taguchi is performed. The objective is to establish a correlation among spindle speed, feed per tooth and depth of cut to the three directions of cutting force in the milling process. In this study, the optimum cutting parameters are obtained by the grey relational analysis. Moreover, the principal component analysis is applied to evaluate the weights so that their relative significance can be described properly and objectively. The results of experiments show that grey relational analysis coupled with principal component analysis can effectively acquire the optimal combination of cutting parameters and the proposed approach can be a useful tool to reduce the cutting force.

关键词： high-speed milling grey relational analysis principal component analysis parameters optimization

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工程监理委托代理关系中激励约束与参与约束的研究

秦旋

《中国工程科学》 2007年第9卷第4期页码 45-49

摘要：

基于委托－代理理论对工程监理委托－代理关系中的激励约束与参与约束进行若干拓展研究，与参与约束（IR）相比，激励相容约束（IC）更为重要，一个机制不满足激励约束，那将是一个无效机制。业主想要提高工程监理制度的运作效率，就必须通过相应的激励措施诱使工程师努力工作，使“道德风险”得以抑制，为我国工程监理制度的健康发展提供了有益的启示。

关键词：工程监理业主工程师委托代理激励相容约束参与约束

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一种基于主成分分析的企业并购目标遴选综合评价模型探讨

罗一新

《中国工程科学》 2009年第11卷第11期页码 92-96

摘要：

在广泛调查研究的基础上，提出了并购目标企业的遴选综合评价指标体系，利用主成分法建立了综合评价模型，并结合实际案例进行了分析，结果证明了评价指标体系和遴选评价模型的可行性，并通过建模计算，对多个并购目标进行排序，为我国正处发展期的企业并购活动提供了一种可行的、便于辅助买方企业决策的并购目标遴选综合评价方法。

关键词：主成分分析企业并购目标遴选评价指标体系评价模型

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弧齿锥齿轮主曲率计算的幺正活动标架法

王裕清,梁剑

《中国工程科学》 2001年第3卷第12期页码 68-70

摘要：

曲面上点的主曲率计算是确定轮齿啮合压痕平面投影形状的关键。文章摈弃通常运用啮合原理和坐标变换计算的思路，从曲面本身的性质出发，把幺正活动标架和外微分引入主曲率计算，得到简明、有效的主曲率计算的新算法，并结合压痕公式给出了一个应用实例。该算法可以推广到任意曲面的主曲率计算。

关键词：弧齿锥齿轮主曲率幺正活动标架

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AED-Net——异常事件检测网络 Article

王田, 苗子琛, 陈禹昕, 周毅, 单光存, Hichem Snoussi

《工程（英文）》 2019年第5卷第5期页码 930-939 doi: 10.1016/j.eng.2019.02.008

摘要：

长期以来，在拥挤场景中检测异常事件都是一项具有挑战性的任务。为解决这一问题，本文提出了一种名叫异常事件检测网络（AED-Net）的自监督框架，它由主成分分析网络（PCANet）和核主成分分析（kPCA）组成。该框架以不同场景的监控视频序列为原始数据，通过训练PCANet以提取人群情况的高级语义。kPCA可作为一种单类分类器，被用于识别场景中的异常事件。与目前流行的一些深度学习方法相比，该框架完全是自监督的，因为它只使用正常情况下的视频序列。通过对明尼苏达大学公共监测人类活动数据集（UMN数据集）和加州大学圣地亚哥分校监测异常数据集（UCSD数据集）进行全局和局部异常事件进行检测发现，与其他最先进的方法相比，该方法具有更好的等误差率（EER）和曲线下面积（AUC）。此外，通过增加局部响应归一化（LRN）层，我们对原有的AED-Net进行了改进。结果表明，该改进版在提高框架的泛化能力方面表现出更好的性能。

关键词：异常事件检测异常事件检测网络主成分分析网络核主成分分析

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基于主成分综合模型的矿区农田重金属污染评价

王从陆,吴超,段瑜

《中国工程科学》 2008年第10卷第7期页码 180-183

摘要：

文章尝试利用变量聚类分析方法对矿区附近农田土壤重金属污染的主要污染物进行辨识，并采用综合主成分分析法对矿区附近农田土壤重金属污染情况进行评价和分级。分析结果表明：利用变量聚类分析法可以有效地辨识矿区附近农田土壤重金属污染中的主要成分；运用综合主成分分析法，确定样本的综合主成分，并对其排序和聚类，可以有效揭示矿区附近农田土壤重金属污染物的数据结构、相互关系和不同样品点的污染程度。采用主成分分析方法对矿区附近农田土壤重金属污染情况的评价结果，反映了矿区主要重金属污染物的影响，同时又定量化了土壤复合重金属污染研究。辨识和评价结果可为矿区附近农田土壤重金属污染治理对策的提出和重点治理区域的确定提供参考和指导。

关键词：主成分综合模型矿区农田土壤重金属污染评价

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基于主成分分析法的秦巴山脉区域林业产业发展研究

郑东晖,后华,翟明普,渠美

《中国工程科学》 2020年第22卷第1期页码 120-126 doi: 10.15302/J-SSCAE-2020.01.013

摘要：

林业产业作为国民经济的重要基础性产业，在生态建设中的地位日益突出。本文系统梳理了秦巴山脉区域的林业产业发展现状，详细开展了区域林业产业的优势、劣势、机遇和威胁（SWOT）分析，以专家问卷调查作为数据来源，运用主成分分析方法，以统计分析的方式寻找出对秦巴山脉林业产业发展有较大影响的要素，以之作为区域林业产业发展战略制定的科学依据。研究表明，生态环境问题、集约化程度低、森林旅游业发展机遇、区位优势、资源优势等方面是秦巴山脉区域林业产业发展的主要影响因素；区域林业产业发展重在于生态建设，应利用区位和资源优势，做大做强特色产业，优化产业结构；同时大力发展以森林旅游为主的第三产业，保障区域林业产业的高质量发展。

关键词：秦巴山脉区域林业产业 SWOT分析主成分分析法生态环境

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基于非对称信息的工程监理激励机制研究

曹玉贵,杨忠直

《中国工程科学》 2005年第7卷第10期页码 69-72

摘要：

通过建立考虑业主投资规模、工程监理特质和外生随机变量及其影响程度等因素的业主与工程监理之间的委托-代理模型，分析了非对称信息下工程投资规模、工程监理特质和外生随机变量等因素对激励报酬系数的影响。同时，基于分析和研究结果，提出了设计工程监理激励机制必须考虑的影响因素。

关键词：项目业主工程监理委托代理激励机制

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Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors

Chuanjia JIANG, Pengyi ZHANG

《环境科学与工程前沿（英文）》 2012年第6卷第2期页码 184-194 doi: 10.1007/s11783-011-0309-3

摘要： Carbonyl compounds in indoor air are of great concern for their adverse health effects. Between February and May, 2009, concentrations of 13 carbonyl compounds were measured in an academic building in Beijing, China. Total concentration of the detected carbonyls ranged from 20.7 to 189.1 μg·m , and among them acetone and formaldehyde were the most abundant, with mean concentrations of 26.4 and 22.6 μg·m , respectively. Average indoor concentrations of other carbonyls were below 10 μg·m . Principal component analysis identified a combined effect of common indoor carbonyl sources and ventilation on indoor carbonyl levels. Diurnal variations of the carbonyl compounds were investigated in one office room, and carbonyl concentrations tended to be lower in the daytime than at night, due to enhanced ventilation. Average concentrations of carbonyl compounds in the office room were generally higher in early May than in late February, indicating the influence of temperature. Carbonyl source emission rates from both the room and human occupants were estimated during two lectures, based on one-compartment mass balance model. The influence of human occupants on indoor carbonyl concentrations varies with environmental conditions, and may become significant in the case of a large human occupancy.

关键词： carbonyl compounds indoor air ventilation human occupancy source emission rate (SER) principal component analysis (PCA)

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Application of coupled XFEM-BCQO in the structural optimization of a circular tunnel lining subjected to a ground motion

Nazim Abdul NARIMAN, Ayad Mohammad RAMADAN, Ilham Ibrahim MOHAMMAD

《结构与土木工程前沿（英文）》 2019年第13卷第6期页码 1495-1509 doi: 10.1007/s11709-019-0574-y

摘要： A new structural optimization method of coupled extended finite element method and bound constrained quadratic optimization method (XFEM-BCQO) is adopted to quantify the optimum values of four design parameters for a circular tunnel lining when it is subjected to earthquakes. The parameters are: tunnel lining thickness, tunnel diameter, tunnel lining concrete modulus of elasticity and tunnel lining concrete density. Monte-Carlo sampling method is dedicated to construct the meta models so that to be used for the BCQO method using matlab codes. Numerical simulations of the tensile damage in the tunnel lining due to a real earthquake in the literature are created for three design cases. XFEM approach is used to show the cracks for the mentioned design cases. The results of the BCQO method for the maximum design case for the tunnel tensile damage was matching the results obtained from XFEM approach to a fair extent. The new coupled approach manifested a significant capability to predict the cracks and spalling of the tunnel lining concrete under the effects of dynamic earthquakes.

关键词： ovaling deformation monte carlo sampling XFEM-BCQO maximum principal stress

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Relationships of nitrous oxide fluxes with water quality parameters in free water surface constructed wetlands

Juan WU, Jian ZHANG, Wenlin JIA, Huijun XIE, Bo ZHANG

《环境科学与工程前沿（英文）》 2009年第3卷第2期页码 241-247 doi: 10.1007/s11783-009-0023-6

摘要： The effects of chemical oxygen demand (COD) concentration in the influent on nitrous oxide (N O) emissions, together with the relationships between N O and water quality parameters in free water surface constructed wetlands, were investigated with laboratory-scale systems. N O emission and purification performance of wastewater were very strongly dependent on COD concentration in the influent, and the total N O emission in the system with middle COD influent concentration was the least. The relationships between N O and the chemical and physical water quality variables were studied by using principal component scores in multiple linear regression analysis to predict N O flux. The multiple linear regression model against principal components indicated that different water parameters affected N O flux with different COD concentrations in the influent, but nitrate nitrogen affected N O flux in all systems.

关键词： free water surface constructed wetland nitrous oxide emission water quality parameter principal component analysis multiple linear regression