• Title/Summary/Keyword: Grey Correlation Degree

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Research on the Relation between Transformer Oil Flow Electrification and Electrostatic Current

  • Fu, Qiang;Wang, Rui;Zou, Pinguo;Li, Zhao;Yang, Yang;Xie, Xuejun
    • Journal of Electrical Engineering and Technology
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    • v.10 no.2
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    • pp.610-615
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    • 2015
  • In order to study and obtain the mathematical relation between the electrification degree of transformer oil flow and the electrostatic current, a small amount of data about the electrification degree of oil flow and the corresponding electrostatic current is studied by linear regression method and grey model method. The results show that the linear correlation between the electrification degree and the electrostatic current was not good, and the relation between the electrification degree of oil flow and electrostatic current (i) could be expressed as ${\rho}(0)=0.2049\;i^{(0)}+169.4419$ according to grey model GM (0, 2) when the electrification degree of oil flow is represented by the charge number generated from transformer oil per unit volume, namely the charge density (${\rho}$).

Empirical Analysis of the Influence of Incentive Factors on University Teachers based on Grey Theory: The Case of LinYi University

  • Zhao, Donglong;Cho, Taejun
    • Journal of Distribution Science
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    • v.11 no.9
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    • pp.35-42
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    • 2013
  • Purpose - The objective of this paper is to identify how different incentive factors influence teachers with different ages and professional titles at LinYi University, China. Research design, data, and methodology - A total of 435 university teachers participated in the study, and the Grey Correlation Degree Analysis method was used to analyze the sample data. Results - The results indicated that teachers with different professional titles and ages have different levels of preference on various incentive factors. Young and assistant-level teachers seem to place more importance on incentives than associate and senior-level teachers. Conclusions - This study has some practical implications. First, the principal and school administrators should pay more attention to young and middle-aged teachers and to how these teachers are motivated through monetary incentives as compared to associate or senior-level teachers. Second, school administrators should pay more attention to teachers' opportunities for career growth and should provide more opportunity for academic promotion. In order to stimulate positivity in teachers, school administrators should adopt various incentive systems.

Development and application of a floor failure depth prediction system based on the WEKA platform

  • Lu, Yao;Bai, Liyang;Chen, Juntao;Tong, Weixin;Jiang, Zhe
    • Geomechanics and Engineering
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    • v.23 no.1
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    • pp.51-59
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    • 2020
  • In this paper, the WEKA platform was used to mine and analyze measured data of floor failure depth and a prediction system of floor failure depth was developed with Java. Based on the standardization and discretization of 35-set measured data of floor failure depth in China, the grey correlation degree analysis on five factors affecting the floor failure depth was carried out. The correlation order from big to small is: mining depth, working face length, floor failure resistance, mining thickness, dip angle of coal seams. Naive Bayes model, neural network model and decision tree model were used for learning and training, and the accuracy of the confusion matrix, detailed accuracy and node error rate were analyzed. Finally, artificial neural network was concluded to be the optimal model. Based on Java language, a prediction system of floor failure depth was developed. With the easy operation in the system, the prediction from measured data and error analyses were performed for nine sets of data. The results show that the WEKA prediction formula has the smallest relative error and the best prediction effect. Besides, the applicability of WEKA prediction formula was analyzed. The results show that WEKA prediction has a better applicability under the coal seam mining depth of 110 m~550 m, dip angle of coal seams of 0°~15° and working face length of 30 m~135 m.

DETERMINATION OF LONGISSIMUS MUSCLE AREA IN PIG WITH ULTRASONIC LINEAR ELECTRONIC SCANNER

  • Irie, M.
    • Asian-Australasian Journal of Animal Sciences
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    • v.5 no.2
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    • pp.229-235
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    • 1992
  • The usefulness of a portable linear electronic scanner. B-mode ultrasonic machine, was evaluated for estimating the longissimus muscle area from ultrasonic measurement of the muscle depth in 22 live pigs. The electronic scanner was easy to operate for muscle measurements in live pigs, which did not have to be held but were caged. The cross-sectional images of longissimus muscle and covering muscles and fat appeared on the monitor with grey scale in real time. It was easy to identify the ultrasonograms of fat and muscular tissues because the images differed in the degree of the grey scale. The longissimus muscle had less echogenic image than the other muscles. The boundary lines between first, second or third layers of backfat and the longissimus muscle were distinct on the ultrasonogram. The ultrasonic measurement at the shoulder was not acceptable because of the unstable measurements and the complex tissue structure. The repeatabilities for the measurements of longissimus muscle depth at one-half body length and last rib were acceptable. The simple correlation coefficients between ultrasonic estimates of the muscle depth in live pigs and the actual areas in the carcass, were 0.50 and 0.55 at the last rib and the one-half body length, respectively. Therefore, those positions were similarly suitable to measure. The method of electronic scanner for determining longissimus muscle area from the muscle depth was suitable for practical use in the field because of the simple and inexpensive technique.

Effects of Treatment Process and Brushing Condition on Mechanical Properties of Brushed Fabrics (II) -Drapability and Wrinkle Recovery of Brushed Fabrics- (기모직물의 가공공정 및 기모횟수가 역학적 특성치에 미치는 영향(II) -드레이프성 및 방추성을 중심으로-)

  • Kwon, Hyun-Sun;Kwon, Oh-Kyung;Sung, Su-Kwang
    • Journal of the Korean Society of Clothing and Textiles
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    • v.18 no.5
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    • pp.595-601
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    • 1994
  • This study was accomplished to investigate drape coefficient and wrinkle recovery of brushed fabrics according to treatment processes and brushing conditions. For this study, grey fabrics of blended ratio of polyester 65% : cotton 35% were bleached and dyed. These fabrics were then brushed 1, 3, 5 and 7 times. Drape coefficient and wrinkle recovery of brushed fabrics were measured by drape tester and shirley crease recovery tester respectively. The experimental results were analysed statistically to relate mechanical properties, handle, drapability, and wrinkle recovery 1) Drape coefficients of dyed fabric showed lower values and wrinkle recovery showed higher ones than those of bleached and dyed fabrics. Especially dyed fabric brushed 3 times showed good appearance and form stability. 2) Considering the blocked properties that contribute to the drape coefficient and wrinkle recovery of brushed fabrics, bending and shearing properties had a high degree of correlation with brushed fabrics, and 2HB/W showed a high positive correlation with drape coefficient and a high negative correlation with wrinkle recovery.

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PIV Analysis of Flow around a Submerged Pitch Damping Foil (몰수형 피치댐핑포일 주위 유동의 PIV 해석)

  • Gim, Ok-Sok;Lee, Gyoung-Woo
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.5
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    • pp.410-415
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    • 2012
  • An experimental study is carried out to investigate the near-wake characteristics of a NACA 0018 foil with a flat plate. Two-frame grey-level cross correlation PIV method is used to measure the local flow characteristic around a pitch damping foil to control the vertical motion of high speed crafts in a circulating water channel. The analysis also includes angles of attack 10 and 20 degrees respectively. Reynolds number $Re{\fallingdotseq}3.5{\times}10^4$ based on the chord length(C=100mm) of NACA0018 has been applied during the whole experiments. The distance between the foil and the flat plate is D/C=0.5, 1.0 and 1.5 respectively. The channel effect according as the distance between the foil and the flat plate has a close relation with the velocity distributions around the foil. In the wake of 20-degree of attack, the complex turbulent flow and a thick boundary layer are formed due to the processes of vortex generation and dissipation.

Control effects of the hydrodynamic force of twin rudder in a uniform stream (균일 흐름중에 놓인 쌍동타의 간격변화가 유체력 제어효과에 미치는 영향)

  • Shon, Chang-Bae;Oh, Woo-Jun;Ku, Youn-Kyoung;Gim, Ok-Sok;Lee, Gyoung-Woo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2010.04a
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    • pp.387-388
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    • 2010
  • An open water rudder test was carried out to figure out the flow characteristics around a twin rudder at $Re=1.5\times10^4$. In the analysis, the unique characteristics of a twin rudder, which effects rudder farces, were explained. The analysis is included varying angles of attack fram 10 to 30 degree. In this paper, the measured results has been compared with each other to predict the performance characteristics of a twin rudder's 2-dimensional section by 2-frame grey level cross correlation PIV method. The side force of the rudder could be mainly improved at 0.75L.

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