수조모델을 이용한 메쉬접지극의 접지저항에 관한 연구

김주찬,김성삼,최종규,이충식,고희석,Kim, Ju-Chan,Kim, Sung-Sam,Choi, Jong-Gyu,Lee, Chung-Sik,Koh, Hee-Seog 한국조명전기설비학회 2006 조명·전기설비학회논문지 Vol.20 No.3

최근들어 빌딩내에 있는 많은 전기 전자 통신설비들은 기기 보호 및 안전을 위하여 반드시 접지를 필요로 하며, 고장 전류가 같은 빌딩내에 있는 어떤 접지 시스템으로 흐를 때, 이 전류에 의한 전위상승에 영향을 받아 다른 접지시스템의 전위 상승을 유도할 수 있다. 이러한 전위간섭은 접지극의 표면전위에 의해 영향을 받으며, 전각의 형상과 깊은 관련이 있다. 본 논문에서의 기본적 공식은 전위간섭을 받는 접지극과 전위간섭의 원천이 되는 두 접지극의 표면 전위에 기초하여 추론되었으며, 다중 접지극에 있어서의 전위간섭의 정도는 미리 간단한 모델을 이용하여 시뮬레이션을 실시하였다. 이는 대지위에 설치되는 건조물의 접지저항을 추정하기 위한 것이며, 실제의 현장에서 측정한 접지 저항값과 추정값과의 일치성을 입증하기 위하여 반구형 수조에서 모의 접지시스템의 축적 모델로 실험을 행한 결과, 확실한 메쉬접지극의 접지저항을 얻을 수 있었다. 따라서 수조 모델 실험을 통하여 메쉬접지각의 접지저항을 추정할 수 있음을 보여주고 있다. Recently, a number of equipments related with electricity, electronics, and communication in the same building are needed to the grounding system for safety from unexpected accidents. When the faulted electric current flows into a certain grounding system, the potential rise in that system takes place and it might induce the potential rise to other grounding system. This potential interference was strongly affected by the surface potential, which was deeply related with the electrode shape. In this paper, the fundamental formula was deduced on the basis of surface potential of two grounding electrodes. Which corresponds to source of the potential interference and other grounding electrode, respectively. Therefore, the degree of potential interference in this mesh grounding electrode system was verified by the simple model simulation. In addition, in order to identify the difference between the grounding resistance in the realistic construction site and the expected value from the corresponding simulation, the experiment was performed with model on a reduced scale about the realistic grounding system. It consists of stainless steel hemisphere electrodes in a water tank. From this work, the grounding resistance in the mesh grounding electrode showed the good coincidence results between those. Consequently, it is confirmed that the grounding resistance in the mesh electrode is possible to be estimated by performing the experiment using the water tank model.

빗줄기 제거를 위한 잔차 네트워크와 Fast R-CNN을 통한 폭우 환경에서의 객체 검출 성능 비교

김주찬(Ju-Chan Kim),손창환(Chang-Hwan Son) 한국정보기술학회 2019 Proceedings of KIIT Conference Vol.2019 No.11

최근 인공지능 기술을 기반으로 자율 주행 기술이 발달함에 따라 객체 검출 기법에 대한 연구가 활발히 진행되고 있다. 하지만 컴퓨터 비전 기반의 객체 검출 기법은 폭설, 폭우, 안개와 같은 악천 후 환경에 따라 상당한 영향을 받게 된다. 악천후 조건에서 수집된 영상에서 객체 검출 성능을 높이기 위해서는 빗줄기 패턴이 객체 검출에 필요한 특징 추출에 부정적인 영향을 미치는지를 조사할 필요가 있다. 기존의 연구는 객체 검출과 빗줄기 제거 과정이 서로 독립적으로 연구되고 있으므로 폭우 환경에서의 빗줄기 패턴과 객체 검출 성능과의 연관성을 제시하지 못하고 있다. 따라서 본 논문에서는 빗줄기 패턴이 객체 검출 성능에 미치는 영향을 조사하고자 한다. 이를 위해, 빗줄기 제거를 위한 잔차 네트워크와 객체 검출을 위한 Fast RCNN 네트워크를 각각 학습한 후, 빗줄기 제거 전후의 객체 검출 성능을 정량적으로 비교하고자 한다. 실험을 통해 빗줄기 영상에서 빗줄기를 제거한 후에 평균정밀도가 11.1만큼 향상된 것을 확인하였다. Recently, as the autonomous driving technology is developed based on the artificial intelligence, the study on the object detection is being actively conducted. However, computer vision-based object detection methods are significantly affected by bad weather conditions such as heavy snow, heavy rain, and fog. To improve the performance of object detection for images collected under bad weather conditions, it is necessary to investigate whether the rain pattern has a negative effect on feature extraction required for object detection. Existing studies have not been able to suggest the correlation between rain patterns and object detection performance in heavy rain environment because object detection and rain removal are studied independently. Therefore, this paper investigates the effect of rain patterns on object detection performance. To achieve this, residual network for rain removal and Fast RCNN network for object detection are trained separately, and then object detection performance before and after rain removal is compared. Through experiments, it is confirmed that average precision was improved by 11.1 after removing the rain streaks from rain images.

빗줄기 제거를 위한 구조 인식 잔차 네트워크

김주찬(Ju-Chan Kim),손창환(Chang-Hwan Son) 한국정보기술학회 2020 Proceedings of KIIT Conference Vol.2020 No.10

본 논문에서는 입력 빗줄기 영상에서 빗줄기를 제거하고 텍스처의 선명도를 강화할 수 있는 빗줄기 제거기법을 제안한다. 최근 영상 복원 분야에서 큰 주목을 받고 있는 심층 합성곱 신경망 기법을 빗줄기 제거 분야에 적용할지라도 평탄 영역에서의 빗줄기 잔존 문제와 텍스처 선명도 저하 문제는 여전히 현안으로 남아 있다. 따라서 본 논문에서는 입력 빗줄기 영상에서 빗줄기를 효과적으로 제거하고 텍스처의 선명도를 강화할 수 있는 복원 기법을 제안하고자 한다. 특히 입력 빗줄기 영상으로부터 원본 영상의 라플라시안 필터링 결과인 에지 맵을 추정함으로써, 평탄 영역에서 빗줄기를 제거하고 디테일 영역에서 선명도를 강화할 수 있는 영상구조에 적응적인 구조 인식 잔차 네트워크를 소개하고자 한다. 또한 실험 평가를 통해, 제안한 구조 인식 잔차 네트워크가 소기의 목적을 성취할 수 있으며 기존의 최첨단 기법들보다 정량적 평가에서 더 우수한 성능을 달성할 수 있음을 보이고자 한다. In this paper, rain streaks removal is proposed to remove rain streaks and to enhance the sharpness of textures from input rain images. Even though deep convolutional neural networks, which have recently attracted great attention in the field of image restoration, are applied to rain streaks removal, residual rain streaks on the flat areas and deterioration of texture sharpness in the texture areas remain current issues. Therefore, this paper proposes a restoration method that can effectively remove rain streaks and enhance texture’s sharpness from input rain images. In particular, by estimating the edge map, which is the result of Laplacian filtering applied to the original image, the structure-aware residual network that is able to adaptive to image structures is introduced to remove the rain streaks in the flat areas and enhance the sharpness in the detail areas. Moreover, through experimental evaluation, it is confirmed that the proposed structure-aware residual network can achieve the desired purpose and obtain better performance in quantitative evaluation than the existing state-of-the-art methods.

빗줄기 제거를 위한 구조 인식 잔차 네트워크

김주찬(Ju-Chan Kim),손창환(Chang-Hwan Son) 한국정보기술학회 2020 한국정보기술학회논문지 Vol.18 No.10

In this paper, rain streaks removal is proposed to remove rain streaks and to enhance the sharpness of textures from input rain images. Even though deep convolutional neural networks, which have recently attracted great attention in the field of image restoration, are applied to rain streaks removal, residual rain streaks on the flat areas and deterioration of texture sharpness in the texture areas remain current issues. Therefore, this paper proposes a restoration method that can effectively remove rain streaks and enhance texture’s sharpness from input rain images. In particular, by estimating the edge map, which is the result of Laplacian filtering applied to the original image, the structure-aware residual network that is able to adaptive to image structures is introduced to remove the rain streaks in the flat areas and enhance the sharpness in the detail areas. Moreover, through experimental evaluation, it is confirmed that the proposed structure-aware residual network can achieve the desired purpose and obtain better performance in quantitative evaluation than the existing state-of-the-art methods.

접지극의 전위간섭

김주찬(Ju-Chan Kim),김성삼(Sung-Sam Kim),고희석(Hee-Seog Koh) 한국조명·전기설비학회 2004 한국조명·전기설비학회 학술대회논문집 Vol.2004 No.5월

Recently, there are many electricity, electronics, and communication equipment which need to earthing in the building. When electric current flows into a certain earthing system in the same building, the potential of other earthing system rises. This potential interference require surface potential of electrodes by electrode shape. In this paper basic formula is deduced on the basis of both electrodes surface potential of earth electrode as a source of the potential interference and earth electrode which receive the potential interference. The degree of potential interference as multiple earth electrode is verified the simulated results by means of the simple model in advance.

지진파 특성에 의한 층응답가속도 및 비구조요소의 증폭계수 검토

김주찬(Kim, Ju-Chan),오상훈(Oh, Sang-Hoon) 대한건축학회 2020 대한건축학회 학술발표대회 논문집 Vol.40 No.2

A Study on Ultra Precise Position Control of Servomotor using Analog Quadrature Encoder

김주찬(Ju-Chan Kim),김장목(Jang-Mok Kim),김철우(Cheul-U Kim),최철(Cheol Choi),조한익(Han-IK Cho) 전력전자학회 2005 전력전자학술대회 논문집 Vol.- No.-

This paper describes the ultra precise position estimation of a servomotor using sinusoidal encoder based on Arcsine Interpolation Method. The amplitude and offset errors of the sinusoidal encoder output signals are effectively compensated and on-line tuned by utilizing a low cost programmable differential amp without any special expensive equipments. To theoretically evaluate the practical resolution of this system, the relationship between the amplitude of A/D converter input signal errors and the anticipated resolution is briefly dealt with. The performance of the proposed method is verified by the experiments, by comparing it with position and speed control characteristics of the servomotor driving system using a digital incremental 50,000ppr encoder.

장거리 지진파에 의한 지진피해의 해석적 연구

김주찬(Kim, Ju-Chan),오상훈(Oh, Sang-Hoon) 대한건축학회 2017 대한건축학회 학술발표대회 논문집 Vol.37 No.2

포항지진과 유사규모지진의 비교를 통한 포항지진파 특성 분석

김주찬(Kim, Ju-Chan),오상훈(Oh, Sang-Hoon) 대한건축학회 2018 대한건축학회 학술발표대회 논문집 Vol.38 No.1

고압수전설비의 고조파에 관한 대책

김주찬(Ju-Chan Kim),신수한(Su-Han-Sin),이충식(Chung-Sik Lee),고희석(Hee-Seog Koh) 한국조명·전기설비학회 2004 한국조명·전기설비학회 학술대회논문집 Vol.2004 No.5월

This paper presents the result of survey of case study for harmonics in electrical installations of buildings. Recently, many power electronic equipments(power converter, computers, air conditioners electronic ballasts for fluorescent lamps and so on) are used in office buildings, and harmonic current from them influence the other equipments in a distribution line. Notably, voltage distortion or voltage harmonics may approach or exceed is allowable level in power distribution system. Individual electric power consumers and end-users and responsible for reducing current harmonics while companies or utilities are responsible for reducing voltage harmonics at the point of common coupling in distribution system. As for harmonics, which one of the electric power qualities, it becomes important to obtain harmonic voltage/current distribution of the power system precisely because the use of power electronic apparatus in increasing. To suppress harmonics in electrical installations of buildings, one of many methods suggest that resonance frequencies are controlled by modulating the capacities of high-voltage customer"s capacitors.