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가속도계 배열과 항체의 운동에 따른 GF-INS 의 각속도 추정 성능 비교
이준학(Junhak Lee),김혜원(Heyone Kim),오상헌(Sang Heon Oh),도재철(Jae Chul Do),남창우(Chang Woo Nam),황동환(Dong-Hwan Hwang),이상정(Sang Jeong Lee) 제어로봇시스템학회 2018 제어·로봇·시스템학회 논문지 Vol.24 No.8
Although the angular velocity of a spinning vehicle with a high rotation rate cannot be measured by conventional gyroscopes, the angular velocity of the vehicle can be obtained from a distributed array of accelerometers in the vehicle. In this paper, the angular velocity estimation performance of the GF-INS is examined according to the accelerometer arrangement and vehicle motion. The DOPs between accelerometer measurements and angular-velocity estimates are compared for two cases of accelerometer arrays. In the first case, three accelerometers are placed at the center of gravity and six accelerometers are placed at the center of the face of a cube. In the other case, four accelerometer triads are placed at the center of gravity and three axes. The accelerometers’ outputs are generated for the trajectory of the vehicle, which rotates three times per second and 30 times per second. The angular velocity is estimated from these outputs by using an extended Kalman filter. The variances of the estimation error for the two array cases are compared. The results show that the angular-velocity estimation performance is better when the DOP is small and the rotation rate is large. Additionally, the performance of the GF-INS can be improved by selecting a suitable accelerometer array for the dynamic characteristics of the vehicle.
GR-INS 에서 칼만필터의 차수에 따른 회전 항체의 각속도 추정 성능 비교
이준학(Junhak Lee),김혜원(Heyone Kim),오상헌(Sang Heon Oh),도재철(Jae Chul Do),남창우(Chang Woo Nam),황동환(Dong-Hwan Hwang),이상정(Sang Jeong Lee) 제어로봇시스템학회 2018 제어·로봇·시스템학회 논문지 Vol.24 No.10
In this paper, angular velocity estimation performances of the GR-INS are compared according to the order of the extended Kalman filter. The case in which one axis cannot be measured by a gyroscope and two axes can be measured by gyroscopes is investigated. One triad is placed at the center of gravity and three at axes. Two gyroscopes are placed at the axes where angular velocity can be measured. Mechanization of the GR-INS is derived for the arrangement of accelerometers and gyroscopes. Outputs of MEMS accelerometers and MEMS gyroscopes are generated for the trajectory of the vehicle, which rotates 30 times per second. From the outputs, angular velocity is estimated using an extended Kalman filter for the two cases. In the first case, the extended Kalman filter only estimates an angular velocity of the spinning axis of the vehicle. In the other case, the extended Kalman filter estimates the angular velocities of the three axes of the vehicle. Angular velocity estimation performances of the two cases are compared. The result shows that the angular velocity estimation performance is better when the extended Kalman filter estimates the angular velocities of the three axes. It can be seen from the result that the performance of the GR-INS can be improved by using a Kalman filter with higher order.
액체 이산화탄소 조건에서의 캐놀라 오일 유래의 효소적 바이오디젤 생산
이명구(Myunggu Lee),박철환(Chulhwan Park),조재훈(Jaehoon Cho),이준학(Junhak Lee),이도훈(Dohoon Lee),김상용(Sangyong Kim) 한국생물공학회 2010 KSBB Journal Vol.25 No.4
액체 이산화탄소를 반응용매로 사용하여 메탄올에 의한 효소 활성이 저해되는 것을 방지하고 친환경적이며 에너지 절감 효과가 우수한 바이오디젤 생산 방법을 제시하고자 유기용매(t-butanol, acetone, chloroform, hexane, THF, cyclohexane, toluene)와 액체 이산화탄소 비교실험을 통해 액체 이산화탄소가 기타 유기용매와 같은 메탄올 저해를 방지하는 역할을 함으로써 반응 용매로서의 적합함을 확인하였다. 또한 동일 이산화탄소를 이용한 초임계 이산화탄소와 비교 실험을 수행하여 초임계 이산화탄소를 이용한 바이오디젤 생산과 유사한 결과를 나타냄으로써 액체 이산화탄소를 이용한 바이오디젤 생산방법이 에너지절약형 친환경 바이오디젤 생산에 더욱 적합함을 확인할 수 있었다. 그리고 액체 이산화탄소 상태에서 바이오디젤 생산의 최적화를 통해 고효율 효소는 novozym 435, lipozyme RM IM 및 lipozyme TL IM 중에서 1,3-위치 선택적 특이성을 가진 lipozyme TL IM이 가장 우수함을 확인할 수 있었다. 또한 경제적 최적 조건과 고전환율 최적조건을 도출하여 각각 88.3%, 99.7%의 높은 전환율을 얻었다. 본 연구를 통해 액체 이산화탄소가 메탄올에 의한 효소활성 저해를 방지하는 반응 용매로 적합하며, 지구 온난화의 주요 요인인 이산화탄소를 이용할 뿐 아니라 비독성 용매로서 친환경적이며 초임계 이산화탄소 상태보다 에너지 절감효과가 우수하여 효소적 바이오디젤 생산 방법에 새로운 방안을 제시 할 수 있었다. It has been well known that organic solvents like t-butanol and n-hexane can protect lipases from the inhibition by short-chain alcohols in the enzymatic transesterification. However, use of the organic solvents should be minimized considering their negative effects on environment and human health. Therefore, use of the greener solvents has been pursued in various are as including the enzymatic biotranformation. In this study, the liquid carbon dioxide (LCO₂) was employed as an alternative media for the enzymatic transesterification of canola oil. The conversion in the LCO₂ was comparable with those in organic solvents and the supercritical carbon dioxide, and under optimum conditions, the value reached 99.7%. It is expected that this method can provide a new type of biodiesel production process with higher energy efficiency and lower environmental impact.
이동희(Donghee Lee),양원석(Wonseok Yang),이준학(Junhak Yi),박우룡(Wooryong Park),김현우(Hyeonwoo Kim),남우철(Woochul Nam) 국방로봇학회 2023 국방로봇학회 논문집 Vol.2 No.4
Unmanned aerial vehicles (UAVs) are widely utilized throughout various fields. The swiftness of UAVs enables them to track moving objects by processing their vision data. Tracking a ground object is achieveable with relatively simple control due to the wide field of view of the UAV of the ground acquired from above and the gradual movement of the target object. However, tracking objects with nimble and unexpected movements such as UAVs is difficult. The tracking UAV needs to be controlled swiftly according to the sudden movement of the target object. Abrupt movement of the target object could also provoke errors in visual tracking. Thus, we developed a new tracking system for UAVs that enables them to track another UAV. A state-of-the-art visual detector YOLO-V5 was adopted for visual tracking, and different control schemes were applied to track the target UAV. This system was verified by real flight experiments with a micro air vehicle (DJI TELLO).
항법전 대응을 위한 다중전파측위융복합 시스템 M&S 소프트웨어의 항법환경생성 모듈 설계
김혜원(Heyone Kim),이준학(Junhak Lee),유원재(Won Jae Yoo),오상헌(Sang Heon Oh),이형근(Hyung Keun Lee),소형민(Hyoungmin So),황동환(Dong-Hwan Hwang) 대한전자공학회 2018 대한전자공학회 학술대회 Vol.2018 No.6
In this paper, a navigation environment generation module design method of a multi-radio integrated navigation system M&S software is proposed for countermeasure to navigation warfare. In the proposed design method, measurements of navigation systems are generated and errors caused by jamming attack are added to the measurements. The proposed method is verified by implementing the navigation environment generation module in the M&S software. The errors by jamming attack are observed in the measurements result of the M&S software.