일측 하퇴 의족 착용자의 절단단 길이에 따른 보행특성

조병모,변주남,김기순,김석산,박종 조선대학교 부설 의학연구소 1999 The Medical Journal of Chosun University Vol.24 No.1

This report studied 31 male patients who were in one hospital in Kwangju or came to a prosthesis clinic and are 15 normal control group to analyze the gait characteristics according to the stump length in the prosthesis users with the unilateral below-knee amputations. The patient group was divided into a short stump subgroup of 13 patients and a long stump subgroup of 18 patients according to the stump length, the control group was randomly sampled from 15 males who have similar age, height and weight to the experimental group. The results of analysis are summarized as follows. 1. There were no significant statistical differences of the general characteristics between patient and control groups and there was no difference of characteristics by patient groups except the mean gait distance a day. 2. Of 33 patients with amputation, 18 patients (57.8%) had phantom pain and 25 cases (80.6%) had neuroma. 3. Gait velocity, stride length of the affected side, step length of the sound side and base support among gait characteristics show a significant difference according to the stump length in the state excluding the effects of other factors (p<05) and the group with long stump showed closer gait characteristics to normal persons than those with short stumps. In conclusion, among the patients of unilateral below-knee amputations, the stump length affects the gait characteristics such as gait velocity, stride length, step and base of support and it is found that as the stump length gets longer, it shows the similar characteristics to gait characteristics of normal persons and long unilateral below-knee amputation can secure better gait characteristics.

一部 美容業 從事者들의 織責別 腰痛 有病率과 關聯要因

김춘일,박종,류소연,김석산,김기순,하상호,변주남 조선대학교 부설 의학연구소 1999 The Medical Journal of Chosun University Vol.24 No.1

To find the prevalence and related factors of low back pain experienced by some beauticians. a survey was made toward 252 beauticians in Kwangju City from March 1st to April 1st, 1998. The results were as follows; 1. The prevalence rate of low back pain among the respondents for the last week was 59.5%. 2. The aid group and staff group with low back Pain had significantly longer duration of work than those without low back pain. Managers who had bad posture with twisted or too much extended back showed a significantly higher prevalence of low back pain than those with good posture during work(P<05). 3. Aid group with low back pain showed significantly higher points at total stress score, depression score, general health score and vitality score than those without low back Pain. The staff group with low back pain showed significantly higher points for total stress score, sleep disorder and anxiety score, depression score, general well-being and vitality score than those without low back pain. Managers with low back Pain showed significantly higher points of stress at social performance and self confidence (P<05) than those without low back pain. The above results suggest that low back pain is related to different jobs and work environments for beauticians. So effective measures and further studies against risk factors must be made considering their jobs. To prevent or reduce low back pain, appropriate management of stress for beauticians is necessary.

Skin Region Detection Using a Mean Shift Algorithm Based on the Histogram Approximation

Byun, Ki-Won,Nam, Ki-Gon,Ye, Soo-Young The Korean Institute of Electrical and Electronic 2012 Transactions on Electrical and Electronic Material Vol.13 No.1

In conventional, skin detection methods using for skin color definitions is based on prior knowledge. By experimentation, the threshold value for dividing the background from the skin region is determined subjectively. A drawback of such techniques is that their performance is dependent on a threshold value which is estimated from repeated experiments. To overcome this, the present paper introduces a skin region detection method. This method uses a histogram approximation based on the mean shift algorithm. This proposed method applies the mean shift procedure to a histogram of a skin map of the input image. It is generated by comparing with the standard skin colors in the $C_bC_r$ color space. It divides the background from the skin region by selecting the maximum value according to the brightness level. As the histogram has the form of a discontinuous function. It is accumulated according to the brightness values of the pixels. It is then, approximated by a Gaussian mixture model (GMM) using the Bezier curve technique. Thus, the proposed method detects the skin region using the mean shift procedure to determine a maximum value. Rather than using a manually selected threshold value, as in existing techniques this becomes the dividing point. Experiments confirm that the new procedure effectively detects the skin region.

Gh Mediates α1-Adrenoreceptor-Induced Transactivation of Integrin Signaling and Hypertrophy in Cardiac Myocytes

( Ki Hyun Byun ),( Woo Chul Chang ),( So Yeon Lim ),( Sun Ju Lee ),( Byeong Wook Song ),( Hye Jung Kim ),( Min Ji Cha ),( Ki Chul Hwang ),( Nam Sik Chung ) 한국조직공학·재생의학회 2008 조직공학과 재생의학 Vol.5 No.4

In cardiac myocytes, stimulation of the alpha(1)-adrenoreceptor(AR) leads to a hypertrophic phenotype. The Gh protein(transglutaminase II, TGII) is tissue type transglutaminase that transmits the alpha(1B)-AR signal with GTPase activity. Recent evidence suggests that integrin activation, in concert with G protein activation, might be essential for cardiomyocyte growth.In this study, our objectives were to evaluate how Gh and integrin interact to promote cardiomyocyte hypertrophy and to identify Gh molecular determinants and downstream signals involved. First, we observed the selectivity of alpha-adrenoceptors in norepinephrine(NE)-induced cardiac hypertrophy by protein synthesis and estimation of the constitutive genes MLC-2 and ß-MHC. NE-mediated hypertrophic responses activated ERK1,2 and their upstream regulators MEK1,2, which were inhibited by siRNA for Gh.We also identified significant activation of ß1-integrin in NE-induced cardiomyocyte hypertrophy. In addition, FAK and Shc, a regulator of FAK, were directly related with integrin and Gh protein in NE-induced cardiomyocyte hypertrophy. The activation of FAK and Shc were suppressed by siRNA for Gh. In conclusion, the hypertrophic response induced by norepinephrine in cardiomyocytes occurs through ß1-Integrin/Shc/FAK/MEK1,2/ERKs signal pathways via α1-AR/Gh.

3D 지형도를 이용한 눈 검출

변기원(Ki-won Byun),임재욱(Jae-wook Im),주재흠(Jae-heum Joo),남기곤(Ki-gon Nam) 제어로봇시스템학회 2009 제어로봇시스템학회 합동학술대회 논문집 Vol.2009 No.12

연료전지 분리판의 형상 변화에 관한 전산해석 및 수치적 연구

남기훈(Ki-Hoon Nam),변재기(Jae-Ki Byun),최남현(Nam-Hyun Choi),최영돈(Young-Don Choi) 대한설비공학회 2011 대한설비공학회 학술발표대회논문집 Vol.2011 No.7

Fuel cells have been of great interest to mobile power industries because of their high conversion efficiency and long-period storage on charge. Among various types of fuel cells, most of technical progresses toward commercialization have been achieved on polymer-electrolyte membrane fuel cells (PEMFCs). PEMFCs, however, have been used in limited number of applications because of their high manufacturing cost, especially cost of membrane materials including precious metal catalysts (Pt or Ru). To minimize energy loss in fuel cell operation, there have been various efforts to improve cathode performance since the largest portion of the energy loss is accounted for by the cathodic polarization. In this study, we propose a wave-like design on surface of the cathode channels to improve oxidant delivery to the gas diffusion layers (GDLs).We introduced two factors AD and ER to analyze the result of improving mass transfer after changing the form of separator. This result linearized by interpolation method.

지형 특징 이용한 얼굴 검출시스템 설계

변기원(Ki-Won Byun),남기곤(Ki-Gon Nam),주재흠(Jae-Heum Joo) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6

본 논문은 지형 특징(topographic feature)을 이용한 얼굴 검출시스템을 제안한다. 지형 특징은 지형 맵(terrain map)을 구성하는 12가지 종류의 레이블이며 조명 환경에 강인한 특성을 가진다. 눈 검출은 색상정보를 이용하여 눈 후보 영역을 검출하고 그에 대응하는 지형 맵으로 변환하여 눈 고유의 지형 특징 존재유무를 판단함으로써 수행된다. 제안하는 방법은 기존방법과 비교하여 다양한 조명환경에서 강인하게 얼굴을 검출함을 확인하였다.

PEM 단위 연료전지 가시화 셀을 이용한 당량비 변화에 따른 플러딩 현상에 관한 연구

남기훈(Ki Hoon Nam),변재기(Jae Ki Byun),최영돈(Young Don Choi) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.6

본 논문은 고분자 전해질 연료전지 공기극 유로 내부에서 당량비에 따라 발생하는 플러딩 현상을 가시화를 통해 확인하고, 전류 변화에 따른 물의 운송 특성에 관한 연구를 수행하였다. 공기극 당량비는 1.5, 2.0, 연료극 당량비는 1.5로 고정하여 실험을 수행하였다. 연료전지 공기측 당량비 2.0로 공급하였을 때 1.5와 비교하여 짧은 시간에 물이 생성되기 시작하였으며, 플러딩 영역이 빠르게 생성되는 결과가 나타났다. 또한, 공기극 당량비 1.5로 유지하는 경우 플러딩 영역 이후에 건조화 7.8A 이후 구간에서 건조화가 진행되며, 8A 이후구간에서 건조화가 시작되는 공기극 당량비 2.0에서 작동하는 연료전지와 비교하여 넓은 영역에서 물 생성이 활발하게 이루어져 MEA의 내구성과 수소이온전도도가 우수한 결과를 확인하였다. The objective of this paper is to demonstrate the cathode channel flooding effects at different stoichiometries in proton exchange membrane (PEM) fuel cells by using visualization techniques. The phenomena of liquid water formation and removal caused by current variations were also examined experimentally. Tests were conducted at cathode stoichiometries of 1.5 and 2.0, and the anode stoichiometry was fixed at 1.5. It is found that at an air-side stoichiometry of 2.0, liquid water begins to form and the flooding occurs faster than at an air-side stoichiometry of 1.5. Also, when the air-side stoichiometry of 1.5 is maintained, the dry-out phenomena is observed in the dry-out area 7.8 A following the field of flooding. Thus, a stoichiometry of 1.5 produced better performance in terms of membrane electrode assembly (MEA) durability and hydrogen ion conductivity than did a stoichiometry of 2.0, in which dry-out occurs beyond 8A.

Mean Shift 알고리즘 기반의 히스토그램 근사화를 이용한 피부 영역 검출

변기원(Ki-Won Byun),주재흠(Jae-Heum Joo),남기곤(Ki-Gon Nam) 大韓電子工學會 2011 電子工學會論文誌-SP (Signal processing) Vol.48 No.4

사전에 정의된 피부 색상 정보를 이용한 기존 피부 검출 방법들은 배경과 피부 영역을 분할하는 단계에서 사용되는 임계값을 실험을 통하여 주관적 관점에서 결정하였다. 또한 기존 방법들은 배경 환경과 조명 환경에 따라 각각 다른 임계값을 설정 하였다. 이러한 기존 방법들은 반복 실험을 통하여 추정된 임계값에 따라 성능이 좌우되는 단점이 제시되었다. 제시된 기존 방법들의 단점을 극복하기 위하여 본 논문은 mean shift 알고리즘 기반의 히스토그램 근사화를 이용한 피부 영역 검출 방법을 제안한다. 제안하는 방법은 CbCr 컬러공간에서의 표준 피부색상과 유사도를 비교하여 생성된 입력 영상의 피부맵(skin-map)의 히스토그램에서 mean shift 방법을 이용하여 각각 밝기 영역별로 수렴하는 극대점을 능동적으로 찾아서 배경 영역과 피부영역으로 분할한다. 히스토그램은 픽셀의 명도값에 따라 누적되는 불연속 함수의 형태를 가지므로 베이지 곡선(Bezier curve)기법을 이용하여 연속 가우시안 함수로 근사화된다. 따라서 제안하는 방법은 기존 방법에서처럼 수동적으로 임계값을 설정하는 방법을 사용하지 않고 mean shift 기법을 이용하여 능동적으로 영역 분할점인 극대점을 찾아서 피부 영역을 검출한다. 제안된 방법은 실험을 통하여 강인하고 효율적으로 피부 영역을 검출하였다. At existing skin detection methods using skin color information defined based on the prior knowldege, threshold value to be used at the stage of dividing the backround and the skin region was decided on a subjective point of view through experiments. Also, threshold value was selected in a passive manner according to their background and illumination environments in these existing methods. These existing methods displayed a drawback in that their performance was fully influenced by the threshold value estimated through repetitive experiments. To overcome the drawback of existing methods, this paper propose a skin region detection method using a histogram approximation based on the mean shift algorithm. The proposed method is to divide the background region and the skin region by using the mean shift method at the histogram of the skin-map of the input image generated by the comparison of the similarity with the standard skin color at the CbCr color space and actively finding the maximum value converged by brightness level. Since the histogram has a form of discontinuous function accumulated according to the brightness value of the pixel, it gets approximated as a Gaussian Mixture Model (GMM) using the Bezier Curve method. Thus, the proposed method detects the skin region by using the mean shift method and actively finding the maximum value which eventually becomes the dividing point, not by using the manually selected threshold value unlike other existing methods. This method detects the skin region high performance effectively through experiments.

외기온도 변화에 따른 지역난방 공동주택 다중 열공급제어 알고리즘 개발에 관한 해석적 연구

변재기(Jae-Ki Byun),윤성호(Sung-Ho Yun),남기훈(Ki-Hoon Nam),최영돈(Young-Don Choi),신종근(Jong-Keun Shin) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.11

In this study, we developed a heat supply control algorithm that minimizes the heat loss in the heat distribution pipelines used for supplying heat energy to shared group housing. Controlling the temperature and flow rate of the hot water supplied to the heat exchanger for shared group housing enables us to develop a heat supply control technique that meets the heating load required by each household in a shared apartment building in accordance with changes in the outdoor air temperature, and that minimizes the heat loss occurring in the heat distribution pipeline. A one-year study in 2008 on a 1,473-household D-apartment building in Hwaseong, Gyeonggi-do, South Korea, compared the heat capacity used by each household, as well as the heat capacity supplied to the heat exchanger room of the apartment housing building, to calculate the amount of heat loss in the heat distribution pipeline. The results confirmed that 24.1% of the heat supplied was lost in the piping.