5㎾t급 접시형 태양열 집열기의 설계 및예비 성능실험

서주현(Seo Joo-Hyun),마대성(Ma Dae-Sung),김용(Kim Yong),서태범(Seo Tae-Beom),한귀영(Han Gui-Young) 한국태양에너지학회 2007 한국태양에너지학회 논문집 Vol.27 No.4

The 5㎾t dish solar collector is designed and the preliminary performance test for this is carried out. The diameter of the parabolic dish is 3.2 m, and its focal length is 2 m. It consists of 10 small reflectors which have their own curvatures, and the effective reflecting area is 5.9 ㎡, and the rim angle of the dish is 43.85°. The reflectivity of reflectors is 0.95, and the thermal capacity of the system is about 5 ㎾ thermal. The aperture diameter of the cylindrical-shape receiver which is made of stainless steel is 100 ㎜, and the height is 210 ㎜. A quartz window is installed at the receiver aperture to minimize the convective heat loss and prevent air leakage. In order to increase the heat transfer area, porous materials (nickel-alloy) are inserted into the receiver. Air flows into the upper part of the receiver which is the opposite side of the aperture. After the air flows through the inside of the receiver, that goes out of the receiver through 3 exits which are located near the aperture. The volumetric flow rates of air are varied from 600 to 1200 L/min. The results show that the system efficiency and receiver efficiency increase as the volume flow rate increases.

공기식 흡수기의 유동 방향에 따른 5kW_t급 접시형 태양열 집열기의 열성능 분석

서주현(Seo, Joo-Hyun),강경문(Kang, Kyung-Moon),이주한(Lee, Ju-Han),오상준(Oh, Sang-June),서태범(Seo, Tae-Beom) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.05

The thermal performance of air receiver with a change of flow direction for dish solar collector. This system is installed and operated in Incheon, Korea. The thermal capacity of the system is about 5 kW thermal. The aperture diameter of the cylindrical-shape receiver which is made of stainless steel is 100 mm, and the height is 210 mm. Experiments are being carried out to investigate the thermal performance variation of the receivers with several design parameters such as the shape of the receiver, the flow directions and the flow rate of air. First, air flows into the upper part of the receiver, which is the opposite side of the aperture. After the air flows through the inside receiver, that goes out of the receiver through 3 exits which are located near the aperture. Second, air flows into the backside of the receiver, Which is the forward side of the aperture. After the air flows through the inside receiver, that goes out of the receiver through 1 exit. The results show that the system efficiency and receiver efficiency increase as the volume flow rate increases as expected.

반사경 배치 및 흡수기 형상에 따른 접시형 태양열 집열기의 복사 열손실 해석

서주현(Seo Joo-Hyun),마대성(Ma Dae-Sung),김용(Kim Yong),강용혁(Kang Yong-Heack),서태범(Seo Tae-Beom) 한국태양에너지학회 2007 한국태양에너지학회 학술대회논문집 Vol.- No.-

The radiative heat loss from a receiver of a dish solar collector is numerically investigated. The dish solar collector considered in this paper consists of a receiver and multi-faceted mirrors. In order to investigate the performance comparison of dish solar collectors, six different mirror arrays and four different receivers are considered. A parabolic-shaped perfect mirror of which diameter is 1.40 m is considered as the reference for the mirror arrays. The other mirror arrays which consist of twelve identical parabolic-shaped mirror facets of which diameter are 0.405 m are suggested for comparison. Their reflecting areas, which are 1.545 ㎡, are the same. Four different receiver shapes are a conical, a dome, a cylindrical, and a unicorn type. The radiative properties of the mirror surfaces and the receiver surfaces can vary the thermal performance of the dish solar collector so that various surface properties are considered. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the receiver to the environment. The Monte-Carlo method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. Based on the calculation, the unicorn type has the best performance in receiver shapes and the STAR has the best performance in mirror arrays except the perfect mirror.

반사경 배치 및 흡수기 형상에 따른 접시형 태양열 집열기의 열손실 해석

서주현(Joo-Hyun Seo),마대성(Dae-Sung Ma),김용(Yong Kim),강용혁(Yong-Heack Kang),서태범(Tae-Beom Seo) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.1

The radiative heat loss from a receiver of a dish solar collector is numerically investigated. The dish solar collector considered in this paper consists of a receiver and multi-faceted mirrors. In order to investigate the performance comparison of dish solar collectors, six different mirror arrays and four different receivers are considered. A parabolic- shaped perfect mirror of which diameter is 1.40 m is considered as the reference for the mirror arrays. The other mirror arrays which consist of twelve identical parabolic-shaped mirror facets of which diameter are 0.405 m are suggested for comparison. Their reflecting areas, which are 1.545 ㎡, are the same. Four different receiver shapes are a conical, a dome, a cylindrical, and a unicorn type. The radiative properties of the mirror surfaces and the receiver surfaces may vary the thermal performance of the dish solar collector so that various surface properties are considered. In order to calculate the radiative heat loss in the receiver, two kinds of methods are used. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the receiver to the environment. The Monte-Carlo Method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. The collector efficiency is defined as the results of the optical efficiency and the receiver efficiency. Based on the calculation, the unicorn type has the best performance in receiver shapes and the STAR has the best performance in mirror arrays except the perfect mirror.

Honeycomb CFA구조를 갖는 CCD 이미지 센서의 필터특성을 고려한 디모자이킹 알고리즘 개발

서주현(Joo-Hyun Seo),박찬일,정용진(Yong-Jin Jeong) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6

Image sensor requires demosaicking algorithm to obtain color information. Conventional algorithms(bi-linear or edge-adaptive) do not consider color filter characteristics. In this paper we proposed a new demosaicking algorithm for Honeycomb CFA CCD image sensor in which color filter characteristics are utilized. As a result, we could obtain enhanced image by adjusting coefficients of the color transformation equations.

Construction of Fully Automated Protein Structure Modeling System

Joo-Hyun Seo(서주현),Byung-Gee Kim(김병기) 한국생물공학회 2005 한국생물공학회 학술대회 Vol.2005 No.10

5㎾급 접시형 태양열 흡수기의 열전달 성능분석

서주현(Joo-Hyun Seo),이주한(Ju-Han Lee),서태범(Tae-Beom Seo),강용혁(Yong-Heack Kang) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

The thermal performance of the air receiver filled with porous material for 5㎾t dish solar collector installed in Inha University, Korea, is experimentally investigated. The diameter of the parabolic dish is 3.2 m, and its focal length is 2 m. It consists of 10 small pieces of glasses which have their own curvatures, and the effective reflecting area is 5.9 ㎡. The reflectivity of the glass is 0.95, and the thermal capacity of the system is about 5 ㎾ thermal. The aperture diameter of the cylindrical-shape receiver which is made of stainless steel is 100 ㎜, and the height is 210 ㎜. A quartz window is installed at the receiver aperture to minimize the convective heat loss and prevent air leakages. In order to increase the heat transfer area, porous material (nickel-alloy) is inserted into the receiver. Air flows into the upper part of the receiver, which is the opposite side of the aperture. After the air flows through the inside receiver, that goes out of the receiver through 3 exits which are located near the aperture. The volumetric flow rates of air are varied from 600 to 1200 L/min. The thermal efficiency of the receiver ranges from 82% - 92% depending upon the flow rate. The results show that the system efficiency and receiver efficiency increase as the volume flow rate increases as expected. These results from the experiment will be useful for the applications to air heating receivers and solar reactors.

Honeycomb CFA 구조를 갖는 CCD 이미지센서의 필터특성을 고려한 디모자이킹 알고리즘의 개발 및 검증

서주현(Joo-Hyun Seo),정용진(Yong-Jin Jeong) 大韓電子工學會 2011 電子工學會論文誌-SP (Signal processing) Vol.48 No.3

CFA(Color Filter Array)를 사용하는 이미지 센서에서는 컬러정보를 획득하기 위해 디모자이킹 과정을 거치게 된다. 이상적인 컬러특성을 갖는 이미지센서에 적용되는 디모자이킹 방식은 실제로 이미지센서에 바로 적용할 경우 올바른 동작을 장담할수 없는데, 이는 센서마다 그 특성이 다르기 때문이다. 따라서 디모자이킹 알고리즘을 적용할 때에는 각 센서의 특성에 따라서 다르게 적용이 되어야만 한다. 본 논문에서는 Honeycomb CFA방식을 사용하는 CCD 이미지 센서에서 사용되는 디모자이킹 알고리즘을 제안하고, 실제 이미지 센서(CBN385B)의 컬러특성을 고려하여 필터의 계수를 보정함으로써 개선된 성능을 갖는 디모자이킹 알고리즘을 제안한다. 또한 디모자이킹 알고리즘을 하드웨어로 구현하여 그 성능을 비교한다. 제안한 알고리즘을 검증하기 위한 방법으로 전체 ISP시스템을 구현 했으며, 성능을 확인할 지표로 알고리즘 자체성능은 PSNR로 이미지센서의 필터특성의 적용의 결과는 RGB분포도를 이용하였다. 결과적으로 기존의 방법에 비해 PSNR 값이 4~8㏈ 증가하였으며, 실제 이미지센서(CBN385B)에서 Red 성분으로 편중된 현상도 제거하였다. 또한 하드웨어 설계를 통해 소프트웨어적인 연산의 복잡성을 해결하였으며 검증을 위해 Spartan-3E FPGA가 사용되었다. 총 게이트 수는 45K개이며 25 frame/sec의 속도를 보였다. Nowadays image sensor is an essential component in many multimedia devices, and it is covered by a color filter array to filter out specific color components at each pixel. We need a certain algorithm to combine those color components reconstructed a full color image from incomplete color samples output from an image sensor, which is called a demosaicking process. Most existing demosaicking algorithms are developed for ideal image sensors, but they do not work well for the practical cases because of dissimilar characteristics of each sensor. In this paper, we propose a new demosaicking algorithm in which the color filter characteristics are fully utilized to generate a good image. To demonstrate significance of our algorithm, we used a commerically available sensor, CBN385B, which is a sort of Honeycomb-style CFA(Color Filter Array) CCD image sensor. As a performance metric of the algorithm, PSNR(Peak Signal to Noise Ratio) and RGB distribution of the output image are used. We first implemented our algorithm in C-language for simulation on various input images. As a result, we could obtain much enhanced images whose PSNR was improved by 4~8㏈ compared to the commonly idealized approaches, and we also could remove the inclined red property which was an unique characteristics of the image sensor(CBN385B).Then we implemented it in hardware to overcome its problem of computational complexity which made it operate slow in software. The hardware was verified on Spartan-3E FPGA(Field Programable Gate Array) to give almost the same performance as software, but in much faster execution time. The total logic gate count is 45K, and it handles 25 image frmaes per second.

파사드가 의류브랜드 점포이미지와 점포태도에 미치는 영향

서주현 ( Joo Hyun Seo ),이규혜 ( Kyu Hye Lee ) 복식문화학회 2015 服飾文化硏究 Vol.23 No.3

Successful use of displays in stores arouses consumers`` curiosity, and induces them to purchase a product after a visit. Facade is a word meaning an external front wall of a building, and is usually the first point of visual contact for the consumers. The present study is an empirical investigation of external appearance of a clothing store, with a 2×2×2 factorial design of facade, show window, and wall surface material designed for the purpose of the study. Dependent variables were store image variables and attitude toward store. A total of 320 questionnaires from male and female consumers were used for the analysis. Facade type and material had significant main and interaction effects, while show window type had no meaningful effects overall. A facade of irregular design prompted significantly higher levels of perceived ‘elegance’, ‘uniqueness’, and ‘attractiveness’ of the store. Material itself did not have significant influence but did have significant interaction effect with facade design. The interaction effect was found in store attitude as well. In order to create a positive store attitude, a concrete material facade should have an irregular design. Companies owning fashion brands should carefully select facade type and wall surface material in the visual merchandising strategies of a store.

행정학 분야에서 설문조사를 이용한 연구의 방법론의 문제점 분석

김태일(Tae Il Kim),서주현(Joo Hyun Seo) 한국행정학회 1998 韓國行政學報 Vol.32 No.3

본 논문은 1991년부터 1997년까지 한국행정학보에 실린 논문들 중에서 설문조사를 이용한 연구들의 방법론적 문제점을 분석하였다. 설문구성, 표본추출, 자료분석으로 이어지는 설문조사의 각 단계에서 연구의 타당성을 확보하기 위하여 요구되는 사항들을 고찰한 후, 이들과 관련하여 분석대상 논문들로부터 발견되는 문제점들에 대하여 논의하였다. 그리고, 설문조사를 이용한 연구의 타당성을 높이기 위하여 다음의 사항들을 제안하였다. 1) 실증연구의 수행자들이 방법론의 타당성에 대하여 보다 많은 주의를 기울이고 연구결과의 발표 과정에서 좀 더 솔직해질 것, 2) 실증연구의 심사시에는 내용의 적합성과 함께 방법론의 타당성에 보다 엄격해질 것, 3) 기고 논문에 대하여 자료 제출을 요구할 수 있을 것, 4) 비평논문의 게재를 활성화할 것.