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- 저자 : 이철수(Lee, Chul soo) (검색결과 388 건)
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이철수,박광렬,Lee, Cheol-Soo,Park, Gwang-Ryeol 대한산업공학회 1998 산업공학 Vol.11 No.2
The letters of the automobile tire are usually engraved on the side-wall. The shape of the side-wall is a sculptured surface generated by the rotational sweeping of a profile curve. The letters laid on the side-wall are usually designed by a 2-dimensional CAD. It is impossible to machine the letters on the surface accurately by 3-axis NC machining, because the axis of cutter should be tilted to align with the normal vector of the surface. In this case. the degree of freedom for the machine is at least four. This paper describes an idea for tool path generation of a 4-axis machine by using the 2-dimensional CAD data of the letters and the surface of the side-wall. This study includes the following procedures; (1) measuring the profile of the side-wall surface and curve-fitting of the measured points. (2) the 'non-parallel projection' of the letters on the side-wall, and (3) an inverse kinematics of the 4-axis lettering machine. Procedures in this paper are programmed in C-language on Windows95 environment. With a PC based CNC controller and a 4-axis lettering machine. these are tested sucessfully for the practical use.
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상호 결합을 이용한 광대역 E-면 H 섹터 혼 위상 배열 안테나 설계
이철수,백정기,Lee, Cheol-Soo,Pack, Jeong-Ki 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.6
H 섹터 혼 안테나는 일정한 빔 커버리지를 가지면서 빔 조향을 하는 광대역 위상 배열 송신기의 복사 소자로 유용하다. 본 논문에서는 상호 결합을 이용하여 3:1 주파수 대역과 ${\pm}60^{\circ}$의 빔 조향 범위를 갖는 광대역 E-면 H 섹터 혼 위상 배열 안테나를 설계하였다. 주자계면에서 반전력 빔 폭이 $30{\sim}50^{\circ}$을 갖는 H 섹터 혼 안테나를 설계하였다. 도파관 시뮬레이터를 이용하여 상호 결합을 포함하는 능동 반사 계수를 계산하였고, 광대역 주파수 범위에서 상호 결합에 의하여 능동 반사 특성이 개선되었다. 이러한 결과를 이용하여 $8{\times}1$ H 섹터 혼 위상 배열안테나를 제작하였다. 주자계면에서의 반전력 빔 폭과 능동 반사 계수의 측정 결과는 시뮬레이션 결과와 잘 일치하였다. 빔 조향된 복사 빔들의 첨두치 패턴은 능동 소자 패턴과 잘 일치하였다. 3:1 주파수 대역과 빔 조향 범위에서 능동 반사 계수는 대부분 0.3 이하로 측정되었다. An H-sector horn antenna has a constant beam coverage characteristic and it can be useful for application to a wide band phased array antenna system. In this paper, we designed a broadband E-plane H-sector horn phased-array antenna, which has a 3:1 bandwidth and ${\pm}60^{\circ}$ beam steering capability. An H-sector hem antenna was designed to have $30{\sim}50^{\circ}$ half-power beam width in the principal H-plane. The active reflection coefficient including mutual coupling was calculated using a waveguide simulator, and the active reflection characteristic was improved by mutual coupling over wide frequency range. Using these results, an $8{\times}1$ H-sector phased array antenna was fabricated. The measurement results for the half-power beam width in the principal H-plane and the active reflection coefficient showed a good agreement with the simulation results. The peak-value pattern in the steered radiation beams also agreed well with the active element pattern. The measured active reflection coefficients within the beam steering range are mostly less than 0.3 over the 3:1 frequency range.
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6MV 선형가속기에서 Al/Cu에 관한 여과판 사용시 전자오염 감소에 관한 연구
이철수,Lee, Cheol-Su 대한방사선치료학회 1996 大韓放射線治療技術學會誌 Vol.8 No.1
The secondary electrons developed by interaction between primary beam and a tray mounted for blocks in Megavoltage irradiation result in excess soft radiation dose to the surface layer. To reduce this electron contamination, electron filters have been used to be attached under a tray. Various filters with Cu and Al plates in six different thickness and Cu/Al combined plates in 3 different thickness were tested to measure the reduction rate of secondary electron contamination to the surface layer. The measurement to find optimal filter was performed on 6MV linear accelerator in $10 cm{\times}10 cm$ field size and fixed 78.5cm source to measurement points distance from surface to maximum build up point in 2mm intervals. The result was analyzed as the ratio of measured doses with using filters, to standard doses of measured open beam. The result of this study was fellowing : 1. The contaminated low energy radiation were mainly produced by blocking tray. 2. The surface absorbed dose was slowly increased by increasing irradiation field size but rapidly increased at field size above $15cm{\times}15cm$. 3. Al plate upto 2.5mm thickness used as a filter was found to be inadequate due to the failure of reduction of the surface absorbed dose below doses of the under surface upto the maximal build up. Cu 0.5mm plate and Cu 0.28mm/A1 1.5mm compound plate were found to be optimal filters. 4. By using these 2 filters, the absorbed dose to the surface were effectively reduced $5.5\%$ in field size $4cm{\times}4cm,\;11.3\%$ in field size $10cm{\times}10cm,\;22.3\%$ in field size $25cm{\times}25cm$. 5. In field size $10cm{\times}10cm$, the absorbed dose to the surface of irradiation was reduced by setting TSD 20cm at least,. but effective and enough dose reduction could be achieved by setting TSD 30cm as 2 optimal filters used. 6. More surface dose absorbed at TSD less than 7.4cm with a tray and filters together indicated that soft radiation was also developed by filters. 7. The variation of PDD by the different size of irradiation field was minimal as 2 optimal filters used. There was also not different in variation of PDD according to using any of two different filters. 8. PDD was not effected either by various TSD or by using the different filter among two.
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컴퓨터 비젼에 의한 PCB 검사를 위한 검사 정보 생성 시스템 개발
이철수,고은희,Lee, Cheol-Soo,Go, Eun-Hee 대한산업공학회 1998 산업공학 Vol.11 No.2
For the PCB inspection by computer vision, in some cases, the MRLC file should prepared. The MRLC file contains a RLC(Run Length Code) and a direction flag. In this paper, a generating method of MRLC is described. It is composed of two procedure as followings; (i) rasterizing Gerber file which is a vectorized image of PCB panel, and (ii) calculating a MRLC that is useful for the inspection as a template image. The suggested procedures are written in C-language and executable on Windows 95 and Windows NT.
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이철수,이강원,Lee, Chulsoo,Lee, Kangwon Korea Water Resources Association 2015 한국수자원학회논문집 Vol.48 No.12
본 논문은 선형계획모형을 이용하여 H 아리수 정수 센터의 최적 취수량 결정 방법을 연구 하였다. 현재 H 아리수 센터에서는 관리자의 경험과 숙련도에 의지하여 취수량을 결정하고 있다. 그런데 매시 변하는 수요를 만족 시키면서 시간대별로 요금이 서로 다른 전력의 사용을 최소화 하는 취수량 결정은 근무자들의 경험과 숙련도를 넘어서는 간단한 문제가 아니다. 따라서 수리적 기법 중 하나인 선형계획모형을 이용해 취수량을 결정하고, 비용 절감을 시도하였다. 본 연구에서 제안한 선형계획 모형은 수요예측치를 기본 입력자료로 사용하고 있는데 예측오차가 발생할 경우 정수지 높이 제한을 위반하는 경우가 발생한다. 이를 해결하기 위해서는 정확한 수요예측이 선행되어야 한다. 그러나 아무리 좋은 예측 기법을 사용하더라도 실수요와 오차는 있게 마련이고 이는 여전히 높이 제한의 제약을 만족 시키지 못하는 결과를 불러일으킨다. 따라서 예측오차를 수용 할 수 있는 안전 마진 상수를 이용한 대안을 제안하였다. 본 연구에서 제안한 선형 계획 모형을 통한 취수량 결정은 수위 모니터링을 위해 항시 작업자가 근무 할 필요가 없기 때문에 인건비 면에서도 많은 절약이 예측되어 총 비용 감축은 훨씬 더 많으리라 기대된다. Currently, the H purification plant determines the hourly water intake amount based on operator experience and skill. Therefore, inevitably, there are deviations among operators. While meeting time-varying demand and maintaining the proper water level in the clean water reservoir, the methodology for minimizing electricity cost, when dealing with different electricity rate time zones, is a very complicated problem, which is beyond an operator's capability. To solve this problem, a linear programming (LP) model is proposed, which can determine the optimal hourly water intake amount for minimizing the daily electricity cost. It is shown that an inaccurate estimate for the hourly water usage in the demand areas causes the water level constraint to be violated, which is the weak point of the proposed LP method. However, several examples with real-field data show that we can practically and safely solve this problem with safety margins. It is also shown that the safety margin method still works effectively whether the estimate is accurate or not. The operators need not attend the site at all times under the proposed LP method, and we can additionally expect reductions in labor costs.
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