• 복식
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• 제56권4호
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• pp.160-170
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• 2006

The purpose of this study is to analyze the image of color combination in fashion design. For this study 14,121 color samples were collected from 116 fashion brands selected by the market segmentation based on the results of the previous studies. The brands have high market share and brand recognition in each segmental market. The color samples were measured by spectrophotometer and analyzed by the Munsell's H V/C and CIE $L^*a^*b^*$ value. The representative colors of each market were selected concerning the tensity in CIE $L^*a^*b^*$ color space and the distance between the color samples. h4 a result, 2,213 representative colors were chosen. These color samples composed top and bottom color combination samples by the program 'Item Comparator' that calculated the color differences$({\Delta}E^*)$. Top includes the items such as blouse, shirt, and coats, bottom includes the items such as skirt and pants. The color combination samples were divided into two groups. In one group ${\Delta}E^*$ was less than 30, and In the other group ${\Delta}E^*$ was 30 or more. For investigating the image of color combination, 480 rotor combination samples were classified. The image adjectives for the survey from preceding studies and brand dictionaries were 'classic', 'modern', 'feminine', 'casual', and 'romantic', which have highly preferred in women's wear brands. The result of the study is as follows; For 'classic' 'image, YR, and greyish tone were generally preferred. In the color combination of 'casual' image, the samples with PB color and greyish tone were preferred. For 'feminine' image, RP was preferred as a top color, R, RP, P were preferred as a bottom color. For 'casual' image, PB was preferred as a top color, PB, B were preferred as a bottom color. For 'romantic' image, RP was preferred as a top color, R, P were preferred as a bottom color. The bigger the color differences between the color combination samples were, the more remarkable the image of color combination samples was.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.491-494
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• 2009

This paper introduces the design concepts and characteristics of WinDS3000$^{TM}$ which is a trade mark of Doosan's 3MW offshore/onshore wind turbine. WinDS3000$^{TM}$ has been designed in consideration of high RAMS (Reliability, Availability, Maintainability and Serviceability) and cost effectiveness for the TC Ia condition in GL guideline. An integrated drive train design with an innovative three-stage gearbox has been introduced to minimize nacelle weight of the wind turbine and to enhance a high reliability for transmission. A permanent magnet generator with full converter system has been introduced to get higher efficiency in part load operation, and grid friendliness use of 50 Hz and 60 Hz grid. A pitch regulated variable speed power control with individual pitch system has been introduced to regulate rotor torque while generator reaction torque can be adjusted almost instantaneously by the associated power electronics. An individual pitch control system has been introduced to reduce fatigue loads of blade and system. The wind turbine has been also equipped with condition monitoring and diagnostic systems in order to meet maintainability requirements. And internal maintenance crane in nacelle has been developed. As a result, the maintenance cost was dramatically reduced and maintenance convenience also enhanced in offshore condition.

• International Journal of Fluid Machinery and Systems
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• 제8권2호
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• pp.102-112
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• 2015

In the Nordic grid, a trend observed the recent years is the increase in grid frequency variations, which means the frequency is outside the normal range (49.9-50.1 Hz) more often. Variations in the grid frequency leads to changes in the speed of rotation of all the turbines connected to the grid, since the speed of rotation is closely related to the grid frequency for synchronous generators. When the speed of rotation changes, this implies that the net torque acting on the rotating masses are changed, and the material of the turbine runners must withstand these changes in torque. Frequency variations thus leads to torque oscillations in the turbine, which become dynamical loads that the runner must be able to withstand. Several new Francis runners have recently experienced cracks in the runner blades due to fatigue, obviously due to the runner design not taking into account the actual loads on the runner. In this paper, the torque oscillations and dynamic loads due to the variations in grid frequency are simulated in a 1D MATLAB program, and measured grid frequency is used as input to the simulation program. The maximum increase and decrease in the grid frequency over a 440 seconds interval have been investigated, in addition to an extreme event where the frequency decreased far below the normal range within a few seconds. The dynamic loading originating from grid frequency variations is qualitatively found by a constructed variable $T_{stress}$, and for the simulations presented here the variations in $T_{stress}$ are found to be around 3 % of the mean value, which is a relatively small dynamic load. The important thing to remember is that these dynamic loads come in addition to all other dynamic loads, like rotor-stator interaction and draft tube surges, and should be included in the design process, if not found to be negligible.

• 한국기계가공학회지
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• 제15권6호
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• pp.129-135
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• 2016

There have been many types of development and commercialization efforts for superconducting power applications with the continuous development of High Temperature Superconducting (HTS) conductors. In particular, HTS power cables are going to be commercialized in real power grids. A cryogenic refrigeration system should be used to keep it below 77 K, and its required cooling capacity continuously increases as the unit length of the HTS power cable increases. Among the many kinds of cryogenic refrigerator, a reverse Brayton refrigerator that uses turbo expanders is a promising refrigerator due to its efficiency and reliability. Among the various components in refrigerators, the cryogenic turbo-expander is the most important part for increasing efficiency and assuring reliability. The design of a 300 W class turbo-expander is described in this paper prior to the development of a 10 kW class turbo expander, which is the required capability for the commercialization of a HTS power cable. The impeller shape and rotation speed are determined based on the cycle analysis. The Eigen frequency and harmonic analysis are conducted with gas bearings at cryogenic temperatures to determine the operational stability.

• 복식
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• 제59권2호
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• pp.1-17
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• 2009

This study is to understand the characteristics of Korean Women's Jeogories in modern times on the changes of its color and coloration over the time. The research was that the characteristics of the costumes produced in modern times ($1890{\sim}2000$) can be categorized into six periods according to the change of times. 1106 women's Jeogories were researched intensively in order to understand them, the conclusions are following: When the Chi-Square Test is applied to conduct cross analγsis of the said six periods divided on the basis of relevant theories, it is found that there is just partial difference in the hues in1890-1959 while there has been a big change in the hues of all Jeogories since 1960. It also seems that such a sudden change In hues took place till the end of the 1970s but there have been no significant difference and no distinct changes in hues sin[e the 1980s. As for color tones, high luminosity and low chroma hues were mainly used in all periods, but low luminosity and high chroma hues have been frequently used since the 1960s. It indicates that the long-used conventional and traditional colors gave way to various colors which were freely applied according to the tendency of individualism In the selection of colors as well. As for the coloration, one-color arrangement was predominant in white clothes while the combination of main color Y and supplementary rotor R was overwhelming in two-color arrangement. After the 1960s, not just the five major rotors but diverse colors, including bluish green, dark blue, were used, even varied patterns for linings.

• 전력전자학회논문지
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• 제9권2호
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• pp.112-118
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• 2004

본 논문은 선박 추진 장치를 위한 저속 영역에서 최대 토크를 내는 대용량 BLDCM(Brushless DC motor)의 설계에 관한 연구이다. 기존의 추진 장치용 모터는 직류기 및 권선형 유도 전동기 등을 사용함으로 인하여 유지 보수가 필요하였다. 본 논문에서는 유지 보수가 필요 없고 저속에서 큰 토크를 발생 할 수 있는 BLDCM 설계를 하였다. 설계시 출력 리플 및 진동, 소음을 유발하는 코깅 토크 저감을 고려하기 위해 설계변수로 공극길이와 자극 각 등을 취하여 이의 변화에 대한 최저 코깅 토크를 가지는 최적형상을 구하고, 전동기 특성을 FEM과 Maxwell stress tensor법을 이용하여 해석하였다. 최저의 코깅 토크를 가지며 저속영역에서 최대 토크를 발생 할 수 있는 선박 추진 장치용 SPM type의 BLDCM을 설계하였다.

• 대한기계학회논문집A
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• 제38권1호
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• pp.1-9
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• 2014

로터에 작용하는 불균형한 반복 하중은 풍력발전기에 구조적 하중을 발생시키고 이러한 하중이 구조물에 지속적으로 누적되면 피로 파괴와 수명 단축을 발생시킨다. Individual pitch control(IPC)는 이러한 구조적 하중을 저감시키고 풍력발전기의 작동 수명 연장에 효과가 있는 제어 방법이다. 본 연구에서는 Decentralized LQR(DLQR)과 Disturbance accommodating control(DAC)를 이용한 IPC 설계를 제시한다. DLQR은 로터 회전속도 제어를 위해 사용하였고 DAC는 블레이드에 외란으로 작용하는 바람(난류) 효과를 상쇄하도록 구성하였다. 제시된 IPC제어기의 구조적 하중 저감 효과는 Gain-scheduled PI로 설계된 Collective pitch control(CPC)과 비교하여 확인하였다. 또한, IPC의 구조물 하중 저감 효과를 확인하기 위해 피로 누적에 의한 손상정도를 나타내는 피로등가하중(DEL)을 이용하였다.

• 한국철도학회논문집
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• 제19권4호
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• pp.427-435
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• 2016

본 논문은 트램-트레인 추진용 130kW급 IPMSM 설계에 관한 연구이다. 트램-트레인은 속도 가변 영역이 넓은 특성을 가지고 있다. 그러한 이유로 넓은 속도 가변 특성을 갖는 IPMSM으로 트램-트레인 추진용 전동기로 제안하고, 요구 견인력에 적합한 기초 모델을 설계하였다. IPMSM은 회전자의 형상에 따라 전자기적 특성 및 구조 특성이 상이하게 된다. 따라서 추가적으로 영구자석을 분할하여 Bridge를 추가한 형상으로 변경한 제안 모델도 설계하였다. 기초 모델과 제안 모델을 유한요소해석을 통해 부하 특성 및 구조 특성을 분석하여 최종적으로 트램-트레인 추진용 IPMSM에 만족하는 모델을 도출하였다.

• 항공우주시스템공학회지
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• 제15권5호
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• pp.106-112
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• 2021

본 논문에서는 군에서 운용하고 있는 회전익 항공기의 후방 동체 상부에 블레이드 형상을 가진 안테나 장착 설계와 구조 건전성 해석을 수행하였다. 항공기 운항 중 안테나 또는 지지 구조물이 파손되면 기체에서 분리되어 로터 부위 및 블레이드와 충돌할 수 있다. 이 경우 항공기가 추락에 이를 수 있는 위험한 상황이 되기 때문에 반드시 개조 구조물들에 대한 구조 해석을 통해 구조적인 안전성을 확보해야 한다. 안테나 신규 장착 부위와 개조 부위에 대한 설계 요구 조건을 분석하고, 개조 전/후 항공기에 작용하는 하중을 적용하였다. 본 연구에서는 안테나 신규 장착 부위와 개조 부위에 대한 설계 요구 조건을 분석하고, 개조 전/후 항공기에 작용하는 하중을 적용하여 지지 구조물에 대한 구조해석을 수행하여 안전성을 확보하였다. 유한요소 모델을 구성하여 응력과 변형량을 확인하고 이론적인 분석 방법을 통해 유한요소 모델을 검증하였다. 이를 토대로 설계된 구조물의 구조 건전성을 확인하였다.

• 한국환경복원기술학회지
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• 제22권1호
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• pp.73-84
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• 2019

In this research, it is a basic study to investigate the population of birds using UAVs. The research area is Ardeidae species(ASP) habitat and has long-term monitoring. The purpose of the study is to compare the ASP populations which analyzed ground observational survey and UAVs imagery. We used DJI's Mavic pro and Phantom4 for this research. Before investigating the population of ASP, we measured the escape distance by the UAVs, and the escape distances of the two UAVs models were statistically significant. Such a result would be different in UAV size and rotor(rotary wing) noise. The population of ASP who analyzed the ground observation and UAVs imagery count differed greatly. In detail, the population(mean) on the ground observation was 174.9, and the UAVs was 247.1 ~ 249.9. As a result of analyzing the UAVs imagery, These results indicate that the lower the UAVs camera altitude, the higher the ASP population, and the lower the UAVs camera altitude, the higher the resolution of the images and the better the reading of the individual of ASP. And we confirmed analyzed images taken at various altitudes, the individuals of ASP was not statistically significant. This is because the resolution of the phantom was superior to that of mavic pro. Our research is fundamental compared to similar studies. However, long-term monitoring for ASP of South Korea's by ground observation is a barrier of the reliability of the monitoring result. We suggested how to use UAVs which can improve long-term monitoring for ASP habitat.