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정종민 (Jongmin Jeong),김재승(Jaeseung Kim),윤태성(Tae Sung Yoon),박진배(Jin Bae Park) 대한전기학회 2018 전기학회논문지 Vol.67 No.6
In recent years, a study of power-line inspection using an unmanned aerial vehicle (UAV) has been actively conducted. However, relevant studies have been conducting power-line inspection with an UAV operated by manual control, and they have developed just power-line detection algorithm on aerial images. To overcome limitations of existing research, we propose a drone-based power-line tracking system in this paper. The main contributions of this paper are to operate developed system under configured environment and to develop a power-line detection algorithm in real-time. Developed system is composed of the power-line detection and the image-based tracking control. To detect a power-line in real-time, a region of interest (ROI) image is extracted. Furthermore, clustering algorithm is used in order to discriminate the power-line from background. Finally, the power-line is detected by using the Hough transform, and a center position and a tilt angle are estimated by using the Kalman filter to control a drone smoothly. We design a position controller and an attitude controller for image-based tracking control, and both controllers are designed based on the proportional-derivative (PD) control method. The interaction between the position controller and the attitude controller makes the drone track the power-line. Several experiments were carried out in environments where conditions are similar to actual environments, which demonstrates the superiority of the developed system.
외국인직접투자가 기업의 경제적 성장에미치는 직접적 효과 분석
정종민(Jongmin Jeong),김영규(Youngkyu Kim) 한국혁신학회 2013 한국혁신학회지 Vol.8 No.2
외환위기를 계기로 한국은 외국인직접투자(Foreign Direct Investment; FDI)를 적극적으로 유치하는 정책을 추진했다. 이로 인해 한국의 FDI 유입액이 크게 늘어나 경제전반에 미치는 영향력이 확대되었다. 이런 상황에서 FDI가 한국 경제에 미친 영향을규명하는 작업의 필요성이 대두되었다. 특히 외환위기 이후 이루어진 FDI가 한국 기업에 미친 직접적인 효과가 무엇인지 고찰할 필요가 있다. 방법론적으로는 선택편의(Selection bias) 문제를 해결하기 위해 성향지수매칭(Propensity score matching) 방법론을 사용하였으며, 제조업을 대상으로 분석을 수행하였다. 그 결과, 한국 기업은 FDI를통해 자본형성 및 생산역량 증대, 고용에 대한 효과를 얻은 것으로 나타났다. 그러나생산성 향상, 무역에 대해선 유의미한 효과를 관찰할 수 없었다. 이는 한국에서 이루어진 FDI의 목적이 생산시설 및 시장의 확보에 있고 기술이전이나 국제 네트워크 활용과는 거리가 있었기 때문으로 판단된다. After financial crisis at 1997, Korea pushed ahead with policy which attracting foreign direct investment (FDI). Therefore, FDI inflow to Korea was increased rapidly and influence of FDI on Korean economy was expanded. In this history, need of research which clearing effect of FDI on Korean economy was raised. Especially, it is so important that direct effect of FDI to Korean enterprises after financial crisis at 1997. According this idea, I developed research task. I analyze the performance of enterprises which attracted FDI with manufacturing industry data. To avoid the selection bias problem, I use Propensity Score Matching method. According the result of analysis, Korean enterprises had effects on capital formation, expanding production capacity and job creation. But there are no significant effects on productivity enhancement and prompting trade. This result is due to the purpose of FDI to Korea which securing production facility and market.
소형 쇼케이스용 증기압축사이클에서의 액인젝션을 이용한 포화압축 사이클 가능성 검토
최정(Jeong Choe),정종민(Jongmin Jung),전용석(Yongseok Jeon) 대한설비공학회 2021 설비공학 논문집 Vol.33 No.4
The objective of this study is to decrease the refrigerant temperature at the compressor outlet under high thermal load conditions with low-GWP refrigerants in the showcase vapor compression cycle. When the outside temperature increases, the showcase cycle suffers a reliability problem due to the high discharge temperature. Liquid injection is a good method for decreasing the discharge temperature of the refrigeration cycle. This study presents the development of a simplified simulation model for predicting the performance of a liquid injection showcase cycle. The optimum injection pressures of the showcase cycle with R410A and R32 were presented. In addition, after the quasi-saturation compression cycle was reached through the multi-stage liquid injection control, the effect of reducing the discharge temperature was analyzed. Finally, the optimal number of injections for each of the refrigerant and operating conditions was presented.