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퍼지 추론 및 인공 신경망 알고리즘 결합에 의한 타이어 회전저항 예측
최대원(Daewon Choi),김기현(Gihyun Kim),장석희(Sukhee Jang),박태구(Taeku Park),조춘택(Choontack Cho) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Tire manufacturers are trying to reduce the tire rolling resistance for decreasing vehicle fuel consumption. Tire rolling resistance is caused by hysteretic losses of various tire components. This paper represents a prediction system that can forecast the tire rolling resistance in advance before making tire. The algorithm of Fuzzy Inference and Neural Network was applied tor this prediction system. Tire construction and component factors were treated by Fuzzy Inference and Neural Network Algorithm respectively. The achievement of this paper will be applied to automotive and tire industry to reduce energy consumption.
데이터마이닝을 적용한 타이어 회전저항 성능 예측 프로그램 개발
최대원(Daewon Choi),김기현(Gihyun Kim),조춘택(Choontack Cho) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Tire manufacturers are trying to reduce the tire rolling resistance for decreasing vehicle fuel consumption. Tire rolling resistance is caused by hysteretic losses of various tire components. This paper represents a prediction system that can forecast the tire rolling resistance in advance before making tire. The neural network algorithm of data-mining was applied for this estimation program. This program will indicate tire design guide line to tire engineer correctively and quickly. The achievement of this paper will be applied to automotive and tire industry to reduce energy consumption.
데이터마이닝 기법을 적용한 타이어 FLATSPOT 예측 프로그램 개발
최대원(Daewon Choi),한상협(Sang-Hyub Han),김기현(Gihyun Kim),박태구(Taeku Park),조춘택(Choontack Cho) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Tire FlatSpot is due to a vehicle parked without moving for a long time In general, tire flatspot phemomemon will be disappeared when a driver have a tire rolled for a few minutes. Flatspot is a low harmonic phenomenon and primarily contributes to the third or fourth harmonics of tire run out. The tire non uniformity caused by a flatspot may induce noticeable vibrations in some vehicles during operation in the decay process. The magnitude and decay of a flatspor depends on many factors - tire construction, material creep properties, tire radial load and time duration, inflation, tire and ambient temperatures, tire mileage, etc. This Paper did apply Data Mining Algorithm to prediction program development of Tire FlatSpot. This program will indicate tire design guide line to tire engineer correctively and quickly.
인공신경망을 이용한 타이어 FLAT SPOT 성능 예측 프로그램 개발
최대원(Daewon Choi),김형태(Hyoungtae Kim),김기현(Gihyun Kim),조명국(Myeongguk Cho) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Tire Flat Spot is due to a vehicle parked without moving for a in general, tire flat spot phenomenon will be disappeared when a driver have a tire rolled for a few minutes. Flat spot is a low harmonic phenomenon and primarily contributes to the third or fourth harmonics of tire run out. The tire non uniformity caused by a flat spot may induce noticeable vibrations in some vehicles during operation in the decay process. The magnitude and decay of a flat spot depends on many factors ? tire construction, material creep properties, tire radial load and time duration, inflation, tire and ambient temperatures, tire mileage, etc. This paper represents a prediction system that can Prediction the tire Flat-Spot in advance before making tire. The neural network algorithm of data-mining was applied for this Prediction program. This program will indicate tire design guide line to tire engineer correctively and quickly.
전문가 지식과 퍼지 논리를 적용한 타이어 PRAT 예측 프로그램 개발
최대원(Daewon Choi),김기현(Gihyun Kim),박태구(Taeku Park),조춘택(Choontack Cho) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
It is generally known that the PRAT(Plysteer Residual Aligning Torque) is a tire design factor to affect vehicle pull. This paper was written to predict a tire PRAT using knowledge information and Fuzzy Logic. Input data of this PRAT Prediction Program are Lateral groove angle of tread pattern. Steel Belt Angle and Cap Ply Laying Condition. This program will indicate tire design guide line to tire engineer correctively and quickly.
김정창(Jeongchang Kim),박성익(Sung Ik Park),최대원(Daewon Choi),임형수(Hyoungsoo Lim),김흥묵(Heung Mook Kim) 大韓電子工學會 2010 電子工學會論文誌-TC (Telecommunications) Vol.47 No.8
ATSC (Advanced Television Systems Committee) 방식의 지상파 디지털 TV 방송 시스템은 단일주파수망을 구성하기 위하여 송신기들 및 중계기들이 단일 주파수를 사용할 경우 수신기에서 다중 송신기 및 중계기 신호들이 수신되어 간섭을 초래할 수 있다. 이러한 간섭 문제를 해소하고자 ATSC 기술권고 (recommended practice)에서는 RF 워터마크 (watermark) 방식의 고유한 송신기 식별 코드 (transmitter identification: TxID)를 각 송신기 및 중계기에 할당한 후 이를 송신 및 중계 신호에 부가하여 전송하고 TxID 신호분석기를 통하여 각 송신기 및 중계기에서 송출된 신호가 겪는 채널 환경을 검출하여 송신기와 중계기의 송출전력 및 상대적인 송출시간을 조정함으로써 간섭 문제를 해결하도록 하고 있다. 본 논문에서는 가산 백색 가우시안 잡음 (additive white Gaussian noise: AWGN) 및 다중경로 채널 하에서 TxID 신호가 부가된 지상파 디지털 TV 방송 신호의 역호환성을 분석한다. 전산 실험 및 실험실 테스트, 그리고 필드 테스트를 통하여 상용 디지털 TV 수신기의 threshold of visibility (TOV) 증가량은 AWGN 채널에 비해 다중경로 채널환경에서 더 높게 나타났으나 TxID 신호가 기존 디지털 TV 신호에 비해 30 dB 낮게 부가되어 전송될 경우 상용 디지털 TV 수신기의 평균 TOV 증가량은 0.2 dB 이하로 관찰되었다. 이러한 실험 및 테스트 결과는 RF 워터마크 방식의 TxID 신호가 상용 디지털 TV 수신기에 거의 영향을 주지 않음을 보여준다. In a single frequency network (SFN) for Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, the interferences induced by the multiple transmitters and/or repeaters using the same frequency are inevitable. Since the presence of interferences results in performance degradation of the SFN, it is crucial to manipulate the interferences by adjusting the transmit power and timing of each transmitter and repeater. In the ATSC terrestrial DTV system, in order to facilitate the interference manipulation process, a transmitter identification (TxID) signal which is uniquely embedded in the signal to be transmitted from each transmitter and repeater is recommended. Even though the injection level of the TxID signal is much lower than the DTV signal, the TxID signal injection infects the DTV signal. Hence, the effect of the TxID signal on the DTV signal must be investigated before deployment. In this paper, the effect of the TxID signal on the performance of legacy DTV receivers under additive white Gaussian noise and multipath channel environments is investigated not only with computer simulation but also with laboratory and field tests. The test results show that the average threshold of visibility degradation of the legacy DTV receivers due to the TxID signal injection is less than 0.2 ㏈ at the TxID injection level of -30 ㏈.
조선소의 메가블록 조립작업장을 위한 공간계획알고리즘 개발
고시근(Shiegheun Koh),장정희(Jeonghee Jang),최대원(Daewon Choi),우상복(Sangbok Woo) 대한산업공학회 2011 산업공학 Vol.24 No.1
To mitigate space restriction and to raise productivity, some shipbuilding companies use floating-docks on the sea instead of dry-docks on the land. In that case, a floating-crane that can lift very heavy objects (up to 3,600 tons) is used to handle the blocks which are the basic units in shipbuilding processes, and so, very large blocks (these are called the mega-blocks) can be used to build a ship. But, because these mega-blocks can be made only in the area near the floating-dock and beside the sea, the space is very important resource for the process. Therefore, our problem is to make an efficient spatial schedule for the mega-block assembly yard. First of all, we formulate this situation into a mathematical model and find optimal solution for a small problem using a commercial optimization software. But, the software could not give optimal solutions for practical sized problems in a reasonable time, and so we propose a GA-based heuristic algorithm. Through a numerical experiment, finally, we show that the spatial scheduling algorithm can provide a very good performance.