고주파 대역 통과 필터를 활용한 혼합신호에서의 비정상 호흡 감지

김주오(Ju O Kim),이덕우(Deokwoo Lee) 한국자동차공학회 2020 한국 자동차공학회논문집 Vol.28 No.12

This paper presents an innovative way to detect abnormal respiration from multiple respiration signals. Respiration status is one of the most used indicators for detecting the status of human health. In this study, ultra wide band(UWB) radar is used to measure and estimate respiration signals. UWB radar is used as a tool for measuring the repiratory status of people in both indoor and outdoor environments. By measuring the distance between the radar device and the human breast in inhalation and exhalation, the respiratory status of a person can be estimated in a quantitative and qualitative way. In this paper, mixed respiration signals are simultaneously acquired by the UWB radar. The proposed approach will then attempt to detect abnormal respiration (e.g., apnea) if the abnormality is included in the mixed respiration. Upon completion of the signal acquisition, high-pass filter is simply applied to the acquired signal. The response signal is analyzed and the existence of apnea is determined by adjusting the cut-off frequency of the high-pass filter. In order to substantiate the proposed approach, we have provided simulation results with real respiration signals.

현실적 영상 필터링 방법을 위한 주파수 영역에서의 다각형 형태 필터의 모델링

김주오(Ju-O Kim),김지수(Ji-Su Kim),박철형(Cheol-Hyeong Park),이덕우(Deok-Woo Lee) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.3

본 논문에서는 영상신호를 필터링 하기 위해 필요한 현실적인 수학적 모델을 제시한다. 1차원 신호 뿐 아니라 2차원 또는 다차원 신호처리 및 분석에서 필터는 영상처리, 컴퓨터 비전, 패턴 인식 등의 다양한 분야에서 근본적이고 중요한 과정을 수행한다. 일반적인 신호처리에서 신호를 주파수 영역에서 해석할 경우 1차원 신호 영역에서의 이상적인 (저역통과) 필터는 직사각형 형태를 가지고 있듯이, 2차원 신호의 이상적인 필터는 원 형태를 가지고 있다. 본 논문에서는 주파수 영역에서 활용할 수 있는 실용적이고 효율적인 다각형 형태의 영상 필터 모델을 제안한다. 본 논문은 2차원 영상을 필터링 하기 위해 원형 필터를 사용하는 대신 육각형 형태의 필터를 모델링하여 적용한다. 이것은 무선 통신 시스템에서의 주파수 재사용 개념을 도입함으로서, 영상 필터링에서도 주파수 대역을 효율적으로 사용하기 위함이다. 본 논문에서 제시한 육각형태의 필터를 활용한 영상 필터링의 시뮬레이션 결과를 제시하고, 성능을 PSNR로 계산한 결과 제안한 방법이 이상적인 필터의 대안으로서 가능함을 보인다. In this paper, we propose an approach to design a practical filter and a mathematical modeling for images. In the areas of signal processing, including high-dimensional image processing, the filtering process has been fundamental and crucial in diverse practical applications such as image processing, computer vision, and pattern recognition. In general, the ideal filter is modeled as circular-shaped in the 2D frequency domain as the rectangular shape is ideal for the 1D frequency domain. This paper proposes an approach to modeling practical and efficient image filter in the 2D frequency domain. Instead of employing a circular-shaped filter, this study proposes a polygon-shaped filter inspired by the concept of a hexagon cellular system for frequency reuse in wireless communication systems. By employing the concept of frequency reuse, bandwidth efficiency is also achieved in the frequency domain. To substantiate the proposed approach, quantitative evaluation is performed using PSNR.

슬관절 반월상 연골판의 치유반응

김주오(Ju O Kim),한홍준(Hong Jun Han),이민종(Min Jong Lee),이현(Hyun Lee) 대한정형외과학회 1991 대한정형외과학회지 Vol.26 No.1

소아 외상성 척골 주두성장판 손상의 치료

김주오(Ju-O Kim),전철홍(Churl-Hong Chun),이병창(Byung-Chang Lee) 대한정형외과학회 1991 대한정형외과학회지 Vol.26 No.6

열린사슬운동과 닫힌사슬운동이 큰가슴근과 위팔세갈래근의 근활성도에 미치는 영향

김주오,장상훈,Kim, Ju-O,Jang, Sang-Hun 대한물리치료과학회 2018 대한물리치료과학회지 Vol.25 No.1

Background: The purpose of this study was to investigate the effect of open and close kinetic chain exercise on the muscle activity of pectoralis major and triceps. Method: Twenty healthy male college students were assessed three times over two weeks. The participants were randomly assigned to OKCE(Open Kinetic Chain Exercise) and CKCE(Close Kinetic Chain Exercise). On the first day, the 7th day and the last day, The MP(mean power) and PT(peak torque) of the PM(pectoralis major) and TR(triceps) during the exercise were measured with an electromyography device and the study was compared. Result: In the present study, it was found that Statistical analysis of the measured values at the end of experimental period revealed statistically significant differences in the MP and PT values of TR and PM. Conclusion: These findings suggest that CKCE and OKCE may be an effective physical therapy intervention for strengthening muscular activity in patients with low activity in the upper limb, including normal subjects, although it is not suitable for effective exercise by selecting either CKCE or OKCE.

트레이드밀 전방, 후방 보행 시 속도와 경사도에 따른 하지 근활성도의 변화

김주오,인태성,Kim, Ju-O,In, Tae-Sung 대한물리치료과학회 2017 대한물리치료과학회지 Vol.24 No.1

Purpose: The purpose of this study was to investigate the changes in the activity of the thigh muscle(rectus femoris, vastus medial/ lateralis, hamstring medial/lateralis) which are caused by the change cf lower extremity muscle activity to speed and inclination during forward and backward walking on the treadmill. Method: Twenty healthy young adults were recruited. The subjects were given a warm-up for 1 minute at the speed of 2.0km/h before exercise, and 2km/h to 4km/h from 10% to 4km/h in the frontal and backward walking. Result: In the present study, it was found that the muscle activity of the lateral broad and inward wide muscles increased when the treadmill was backward for 40 seconds without training. And the femur and the muscle were significantly different from 10% to 4km/h(p<.05). Conclusion: These findings suggest that in the treadmill, it is effective in increasing the leg strength in the backward walking than in the forward walking. And it was concluded that muscle activity increased at 4km/h when the speed was 2km/h when backward walking.

다중 열상 카메라 캘리브레이션을 위한 경계부 및 코너 검출

김주오(Ju O Kim),이덕우(Deokwoo Lee) 대한전기학회 2020 정보 및 제어 심포지엄 논문집 Vol.2020 No.10

개선된 화질의 영상을 이용한 열화상 카메라 캘리브레이션

김주오(Ju O Kim),이덕우(Deokwoo Lee) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.4

본 논문에서는 3개의 시점을 가진 열화상 카메라의 캘리브레이션을 수행하는 방법을 제안하고, 카메라의 내부 파라미터 추정 및 그 결과의 정확도를 파악하기 위해 역투영 오류값을 제시한다. 3개의 시점을 가진 카메라는 일반 카메라와 다르게 각 시점마다 겹치는 영상이 존재하지 않고, 획득한 영상의 화질은 일반 카메랄 획득한 영상보다 낮다. 카메라 캘리브레이션은 3차원 실제 영상의 좌표 정보 또는 카메라와 목표물체 사이의 거리를 계산하기 전에 반드시 수행되어야 하는 작업이다. 카메라 캘리브레이션 작업을 통해 얻는 것은 카메라의 내부 및 외부 파라미터이며 내부 파라미터는 카메라의 초점거리, 비대칭계수, 이미지 중심점으로 구성되어 있고, 외부 파라미터는 사용되는 카메라들 사이 또는 사용되는 카메라의 상대적 위치인 회전행렬과 변위벡터로 구성되어 있다. 본 논문에서는 열화상 카메라의 캘리브레이션을 수행하는 방법을 제안하며, 열화상 카메라의 캘리브레이션 수행을 위해 온도에 반응하는 열상 체커보드를 활용한다. 캘리브레이션이 안정적으로 수행되기 위해 본 논문에서는 심층 학습 기반 촬영대상 물체의 화질을 개선하여 코너 추출의 정확도를 높인 후 캘리브레이션 파라미터 계산을 수행하고, 개선된 화질의 영상이 캘리브레이션을 개선한 결과를 제시한다. This paper proposes a method to calibrate a thermal camera with three different perspectives. In particular, the intrinsic parameters of the camera and re-projection errors were provided to quantify the accuracy of the calibration result. Three lenses of the camera capture the same image, but they are not overlapped, and the image resolution is worse than the one captured by the RGB camera. In computer vision, camera calibration is one of the most important and fundamental tasks to calculate the distance between camera (s) and a target object or the three-dimensional (3D) coordinates of a point in a 3D object. Once calibration is complete, the intrinsic and the extrinsic parameters of the camera(s) are provided. The intrinsic parameters are composed of the focal length, skewness factor, and principal points, and the extrinsic parameters are composed of the relative rotation and translation of the camera(s). This study estimated the intrinsic parameters of thermal cameras that have three lenses of different perspectives. In particular, image enhancement based on a deep learning algorithm was carried out to improve the quality of the calibration results. Experimental results are provided to substantiate the proposed method.

Z-Domain에서의 신호해석을 활용한 호흡상태 분류

김주오(Ju O Kim),이덕우(Deokwoo Lee) 한국통신학회 2020 韓國通信學會論文誌 Vol.45 No.12

관절경하 회전근 개 봉합술 후 파열 정도에 따른 통증 회복 양상

김주오,심상돈,노경환,손석준,김설전,양윤혁,Kim, Ju-O,Sim, Sang-Don,Noh, Kyung-Hwan,Shon, Suk-June,Kim, Sul-Jun,Yang, Yun-Hyeok 대한관절경학회 2009 대한관절경학회지 Vol.13 No.2

Purpose: The purpose of this study was to evaluate the pain recovery pattern according to the integrity and to analyze the factors affecting the progress and level of pain postoperatively. Materials and Methods: We examined 153 patients, who were treated with arthroscopic rotator cuff repair. 101 rotator cuff tears were full-thickness tear and 52 were partial tear. The mean follow up duration was 20 months (12~30 months). We evaluated the visual analogue scale, range of motion, ASES (American Shoulder and Elbow Surgeons), and UCLA (University of California at Los Angeles) scores preoperatively and postoperatively. We analyzed the pain recovery pattern between partial and full thickness tear using Student T-test and the factors affecting the progress and level of postoperative pain using multiple regression analysis. Results: The change patterns of visual analogue scale after arthroscpoic repair were similar regardless of the tear integrity. The VAS showed a continuous decreasing pattern, but increased at first 3 weeks postoperatively and at 7 weeks postoperatively, and then, decreased thereafter. The average VAS was ${\leqq}2$ points by postoperative 3 months. The factor affecting the pain score at 3 months was related to the preoperative limitation in forward flexion ($r^2=0.377$, p=0.021). Conclusion: There was no differences of the pain recovery pattern according to the integrity, and the factor affecting the progress of postoperative pain was preoperative angle of forward elevation. So, the appropriate preoperative rehabilitation protocol that can improve motions of the shoulder joint would help to improve the level of postoperative pain and functional recovery.