• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.325-329
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• 2002

This paper is intended as an investigation of the interface between Neutral section insulators and pantograph interface. Neutral section insulators are installed at the boundary between AC catenary system and DC catenary system, which should provide electrical insolation between two different catenary systems and pass the trains without interruption. As the number of the pantographs installed on the train increased, which is necessary for the VVVF inverter drive trains introduced in recent years, there occurs an serious aspects of the interaction between pantographs and Neutral section insulators. These effects hinder the automatic switch operation of MCB(Main Circuit Breaker) after passing through the section insulators, and lead to the extra-ordinary wear of FRP insulator material of section insulators. Countermeasures in terms of the interface between the Neutral secton insulators and electric collection system of train are provided too.

• 한국군사과학기술학회지
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• 제10권3호
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• pp.16-24
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• 2007

The high-frequency analysis method of back-scattering cross section spectrum of rotating targets is established. The time history of the back-scattering cross section is calculated using a quasi-stationary approach, based on a physical optics and a physical theory of diffraction, combining an adaptive triangular beam method to consider the shadow effect. And the spectra of back-scattering cross section by the Doppler effect are analyzed applying a simple fast Fourier transform method to its time history. The numerical calculation for rotating targets, such as rotating metal plates and underwater propeller, are carried out. The time history appears to be periodic with respect to the number of wings. The backscattering cross section spectrum level and its frequency shift are dependent on the rotating speed, direction, and the shape of the targets.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.444-450
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• 2024

Based on multiple measurements of ionization loss, the Time Projection Chamber (TPC) combines strong tracking ability with particle identification ability in a large momentum range, which is an important advantage of TPC detection technology over traditional ionization measurement technology. According to these two characteristics of TPC, applying it to the measurement of fission cross-section can greatly improve the measurement accuracy. During the measurement of the fission cross-section, the number of target nuclei is required to be accurately measured. So this paper introduces a method for measuring the number of ²³⁵U target nuclei using a fission TPC system. The measurement result agrees with the reference value, and relative error is around 1 %.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.583-588
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• 2007

For the purpose of optimum design of RC frame structures. pre-determined section database of column and beam are constructed and arranged in order of the resisting capacity. Then, regression equations representing the relation between section number and resisting capacity are derived. In advance. effective optimization algorithms which search optimized solution quickly using direct search method from these database are proposed. Moreover. the investigation for the applicability and effectiveness of the introduced design procedure is conducted through correlation study for example structures.

• 패션비즈니스
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• 제10권5호
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• pp.135-158
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• 2006

The purpose of this study was to provide for the useful fundamental data by developing an appearl sizing system according to body types for Chinese Adult Female. Thus, it was to improve of fittness and coverage rate of exporting domestic clothing to China. For study, It was measured 1360 female women aged between 19 and 50 who resident in Beijing and Shanghai in China. as a sample, 1381 female women was seleted for development of apparel sizing system. Thus, this study was to characterize body types of Chinese adult female by classifying them into groups and set coverage rate of ready-made clothes by developing an apparel sizing system according to the Women's Wear Specifications(GB/T 1335.2-1997), National Standards of People's Republic of China. As for the method of this study was done during Jun. 23 $\sim$ Aug. 7, 2004. Data analysis were processed by SPSS WIN 10.0 Program was used to for technical statistical analysis. The result was as follows: The clothes dimension for upper and lower body and the coverage rate of body size that had the highest appearance ratio from the entire group was Y-type 160-84$\cdot$160-64(4.6%) and the section 160cm 32.4%, A-type 160-88$\cdot$160-72(3.3%) and the section 160cm 28.1%, B-type 155-88$\cdot$155-78(3.8%) and the section 155cm 27.8%, C-type 150-96$\cdot$150-88(2.5%). The result By setting of representative size number and production coverage rate for Chinese adult female. The representative size number of the entire group was set for 150-80A$\cdot$150-64A(1.0%), 155-84A$\cdot$155-68A(2.6%), 160-88A$\cdot$160-72A(3.3%), 165-84A$\cdot$165-68A (2.8%), 170-96A$\cdot$170-80A(0%). The production coverage rate for each representative size number was SS size the section 150cm 2.8%, size the section 155cm 17.0%, M size the section 160cm 31.6%, L size the section 165cm 25.0%, XL size the section 170cm 12.6% that covered 85.0%.

• Wind and Structures
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• 제20권2호
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• pp.327-347
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• 2015

This paper investigates the effects of Reynolds number (Re) on the aerodynamic characteristics of a twin-deck bridge. A 1:36 scale sectional model of a twin girder bridge was tested using the Wall of Wind (WOW) open jet wind tunnel facility at Florida International University (FIU). Static tests were performed on the model, instrumented with pressure taps and load cells, at high wind speeds with Re ranging from $1.3{\times}10^6$ to $6.1{\times}10^6$ based on the section width. Results show that the section was almost insensitive to Re when pitched to negative angles of attack. However, mean and fluctuating pressure distributions changed noticeably for zero and positive wind angles of attack while testing at different Re regimes. The pressure results suggested that with the Re increase, a larger separation bubble formed on the bottom surface of the upstream girder accompanied with a narrower wake region. As a result, drag coefficient decreased mildly and negative lift coefficient increased. Flow modification due to the Re increase also helped in distributing forces more equally between the two girders. The bare deck section was found to be prone to vortex shedding with limited dependence on the Re. Based on the observations, vortex mitigation devices attached to the bottom surface were effective in inhibiting vortex shedding, particularly at lower Re regime.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1077-1083
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• 2011

Turnout is one of railroad track components. The turnout is used to change train routes to near other sections when keeping the train speed. There are many accidents in the section including the turnout. The number of accidents and errors is 363 for ten years in the section including the turnout and annual average is 36.3. To ensure safety of the turnout, it is necessary to install monitoring systems. By using the monitoring systems, it is able to accumulate related information, develop maintenance and take a step for accidents in advance. Hence, The number of accidents and errors is decreased in the section including the turnout. So, when new turnout is installed, it is needed to use monitoring systems. Therefore, combined turnout management system is needed in Korea. It is possible to perform efficient maintenance because real-time monitoring system by using sensors and data-base management system. In this paper, accidents in the section including domestic turnout are analyzed and foreign combined turnout management system is presented. Hence, articles for installing the combined turnout management system in Korea are proposed.

• 한국안전학회지
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• 제27권6호
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• pp.20-25
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• 2012

Currently, the most important purpose in designing automobile is environment-friendly and safety performance aspect. CFRP(Carbon Fiber Reinforced Plastics) of the advanced composite materials as structure materials for vehicles, has a wide application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness. In this study, experimental investigations are carried out for CFRP single and double hat shaped section member in order to study the effect of various stacking condition. They were cured by heating to the appropriate curing temperature($130^{\circ}C$) by means of a heater at the vacuum bag of the autoclave. The stacking conditions were selected to investigate the effect of the interface numbers. The CFRP single and double hat shaped section members which manufactured from unidirectional prepreg sheets were made of 8ply. The static collapse tests performed and the collapse mode and energy absorption capability were analyzed according to interface number.

• 한국정밀공학회지
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• 제29권10호
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• pp.1050-1055
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• 2012

The bearing coupling section of machine tools is the most important factor to determine their static/dynamic stiffness. To ensure the proper performance of machine tools, the static/dynamic stiffness of the rotating system has to be predicted on the design stage. Various parameters of the bearing coupling section, such as the spring element, node number and preload influence the characteristics of rotating systems. This study focuses on the prediction of the static and dynamic stiffness of the rotating system with the bearing coupling section using the finite element (FE) model. MATRIX 27 in ANSYS has been adopted to describe the bearing coupling section of machine tools because the MATRIX 27 can describe the bearing coupling section close to the real object and is applicable to various machine tools. The FE model of the bearing couple section which has the sixteen node using MATRIX 27 was constructed. Comparisons between finite element method (FEM) predictions and experimental results were performed in terms of the static and dynamic stiffness.

• 여성건강간호학회지
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• 제18권3호
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• pp.200-208
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• 2012

Purpose: This study was aimed to examine the gap between predicted cesarean section rate and real cesarean section rate and it's determining factors of 44 tertiary hospitals. Method: This study is a cross-sectional analysis using the data of 25,623 deliveries in 2009 drawn from homepage of Health Insurance Review and Assessment Service. Data were analyzed with t-test, F-test, Scheff$\acute{e}$ test, and logistic regression. Result: There were statistically significant differences in the gap of cesarean section rate (more gap indicates higher quality of delivery) by grade of nurse staffing and delivery cases. Hospitals with nurse staffing grade 1 to 2 had more possibility to be classified into higher grade in quality of delivery (OR 5.67, 95% CI 1.07-30.08). Also hospitals with over 500 delivery cases had more possibility be classified into higher grade in quality of delivery (OR 4.92, 95% CI 1.14-21.23, respectively). Conclusion: The finding suggests that grade of nurse staffing may influence the real cesarean section rate because nurses do a vital role to prevent unnecessary cesarean section. Further study is required to provide evidence that nurse staffing influence on patient outcome and cost-effectiveness in order to obtain adequate number of nursing staffs.