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광역감시망 적용을 위한 HF 레이더 기반 선박 검출 및 추적 요소 기술
조철진,박상욱,이영로,이상호,고한석,Cho, Chul Jin,Park, Sangwook,Lee, Younglo,Lee, Sangho,Ko, Hanseok 대한원격탐사학회 2018 大韓遠隔探査學會誌 Vol.34 No.2
현재 국내 환경에서의 HF 레이더는 기본적으로 표층해류의 속도와 방위의 측정에 최적화 되어있는 상태이다. 따라서, 이러한 환경하에서 선박을 탐지하는 데에는 큰 환경 잡음과 다수의 오검출로 인하여 기존의 선박 검출 및 추적 기술로는 정밀도에 한계점이 있다. 특히, 국내의 지형환경에 적합한 콤팩트형 HF(High Frequency) 레이더를 선박의 감시에 적용했을 경우에 나타나는 문제점들인 잡음과 간섭으로 인한 원신호 왜곡과 다수의 오검출이 발생하여 성능에 영향을 미치는 것을 극복하기 위한 검출 및 추적 기술이 요구된다. 본 논문에서는 이러한 조건 하에서 적용이 가능한 선박 검출 및 추적 기술을 제안을 하며, 서해에서 운용되고 있는 콤팩트 HF 레이더 사이트에서 획득한 관측 데이터에 적용하여 성능을 평가하였다. 제안된 기법은 선박의 검출에 대한 부분과 검출 결과의 추적에 대한 부분으로 이루어져 있다. 선박의 검출은 CFAR(Constant False Alarm Rate) 기반의 검출기를 활용하였으며, 실제 환경에서 불규칙적으로 획득되는 잡음과 오검출 신호를 줄이기 위한 PCA(Principal Component Analysis) 기반의 부분공간 분리기법을 적용하였다. 또한, 긴 입력 획득 주기(Coherent Processing Interval) 동안에 발생하는 도플러 주파수 변화로 인하여 하나의 선박이 다수의 검출값을 생성하기도 하는데, 이를 결합하기 위한 군집화 기법을 적용하였다. 선박의 검출 결과는 검출에 실패하거나 오검출을 포함시키는 경우도 발생하는데, 이러한 오검출을 줄이기 위한 선박 추적 기법을 적용하였다. 실험 결과에 따르면 제안된 선박 검출 및 추적 기술을 통하여 콤팩트 HF 레이더가 일정 거리에서 선박의 검출 성공율이 우수하다는 것을 확인할 수 있다. This paper introduces core techniques on ship detection and tracking based on a compact HF radar platform which is necessary to establish a wide-area surveillance network. Currently, most HF radar sites are primarily optimized for observing sea surface radial velocities and bearings. Therefore, many ship detection systems are vulnerable to error sources such as environmental noise and clutter when they are applied to these practical surface current observation purpose systems. In addition, due to Korea's geographical features, only compact HF radars which generates non-uniform antenna response and has no information on target information are applicable. The ship detection and tracking techniques discussed in this paper considers these practical conditions and were evaluated by real data collected from the Yellow Sea, Korea. The proposed method is composed of two parts. In the first part, ship detection, a constant false alarm rate based detector was applied and was enhanced by a PCA subspace decomposition method which reduces noise. To merge multiple detections originated from a single target due to the Doppler effect during long CPIs, a clustering method was applied. Finally, data association framework eliminates false detections by considering ship maneuvering over time. According to evaluation results, it is claimed that the proposed method produces satisfactory results within certain ranges.
조철진(Chul-jin Cho),조용현(Yong-hyeon Cho),권삼영(Sam-young Kwon),이기원(Kiwon Lee),장사술(Sasool Jang),유향복(Hyangbok Ryoo) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.5
The pantograph-overhead contact line system is an interface that supplies power to high-speed trains used in many countries including Korea. Due to the fact that power is supplied through direct contact between contact wires and contact strips, wear may occur, increasing the possibility of accidents over periods of time. Therefore, there is a need to establish methods of effectively extracting safety related parameters. In this paper, an image processing based method that calculates and draws graphs of a pantograph’s dynamic stagger is proposed. To assess reliability, the results were compared with data collected from conventional maintenance vehicles.
이우철,조철진,박석인,전동환,송진동,황철성,김성근 한국물리학회 2018 Current Applied Physics Vol.18 No.8
The presence of an AlN interfacial layer in high-k/In0.53Ga0.47As gate stacks improves the interfacial properties and enhances the electrical performance of devices. However, pure AlN is rarely grown by atomic layer deposition (ALD) because of the low reactivity of NH3 toward the common Al-precursor and the predisposition to oxidation of the grown AlN layer. Although a plasma-enhanced ALD technique significantly suppresses the oxygen content in the grown AlN layer, the deterioration of the interface properties by plasma-damage is a critical issue. In this work, an AlON interlayer was engineered by optimizing the NH3 feeding time in thermal ALD to improve the interface quality in Al2O3/AlON/In0.53Ga0.47As capacitors. It was determined that a mere increase in the NH3 feeding time during the ALD of the AlON film resulted in a higher nitrogen incorporation into the AlON interlayer, leading to a reduction in the interface trap density. Furthermore, the out-diffusion of elements from the In0.53Ga0.47As layer was effectively suppressed by increasing the NH3 feeding time. This work demonstrates that simple process optimization can improve the interface quality in high-k/In0.53Ga0.47As gate stacks without the use of any plasma-activated nitrogen source.
이우철,조철진,최정혜,송진동,황철성,김성근 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6
The anomalous frequency dispersion of the accumulationcapacitance, i.e. an increase in the accumulation capacitanceat high frequencies, of Pt/Al2O3/InGaAs metal-oxidesemiconductor(MOS) capacitors was investigated in thisstudy. The anomalous frequency dispersion can be attributedto the considerable effects of parasitic inductance at highfrequencies. The effects of parasitic inductance wereeffectively suppressed by decreasing the capacitor areawithout changing the MOS structure. This suggests that asmaller capacitor area should be used to preciselycharacterize the capacitance-voltage behavior of InGaAs-based MOS devices.
고속카메라를 이용한 전차선 마모 검측 영상처리 알고리즘 개발
박영,조용현,조철진,김원하,Park, Young,Cho, Yong-Hyeon,Cho, Chul-Jin,Kim, Won-Ha 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.8
The measurement of contact wire wear in electric railways is one of the key test parameters to increase speed and maintain safety in electric railways. Wear caused by continuous interaction between pantographs and contact wires has a negative effect on current collection quality and severely damaged contact wires might cause hazardous accidents. This paper introduces a non-contact optical-based contact wire wear measuring system that will replace conventional wear detecting methods conducted by maintenance vehicles or workers. The system is implemented by high-speed cameras that can collect images of contact wires during vehicle operation, a laser used to create images profile of the contact wire surface, and a computer used to process the collected images. The proposed system is designed to assist maintenance of overhead contact lines by creating geometrically plotted images of contact wires to detect contact wire wear during operation on conventional lines or high-speed lines.
김형준,박영,조용현,조철진,김인철,Kim, Hyung-Jun,Park, Young,Cho, Yong-Hyeon,Cho, Chul-Jin,Kim, In-Chol 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.12
The measurement of dynamic stagger in electric railways is one of the key test parameters to increase speed and maintain safety in electric railways. This paper is introduces a non-contact optical-based measuring instrument of a catenary system in electric railways. The instrument is implemented by utilizing a CCD (Charge Coupled Device) camera installed on the roof of a vehicle for vision acquisition and image processing techniques including the Canny edge detector and the Hough transform to detect contact wires and calculate dynamic stagger. To check the validity of our approach for the intended application, we measured stagger of a overhead wire of a Korea Tilting Train (TTX). The non-contact optical-based measurement system proposed in this paper performs real-time stagger measurement of an activated high-voltage contact wire. By results of this paper, the instrument should be applied to assess performance and reliability of newly developed electric railway vehicles.