AN IN-SITU YOUNG'S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

Choi, Young-Chul,Yoon, Doo-Byung,Park, Jin-Ho,Kwon, Hyun-Sang Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.3

Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young's modulus becomes unreliable and in-situ measurement of Young's modulus is required from an engineering point of view. Young's modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young's modulus of two plates.

AN IN-SITU YOUNG’S MODULUS MEASUREMENT TECHNIQUE FOR NUCLEAR POWER PLANTS USING TIME-FREQUENCY ANALYSIS

YOUNG-CHUL CHOI,DOO-BYUNG YOON,JIN-HO PARK,권휴상 한국원자력학회 2009 Nuclear Engineering and Technology Vol.41 No.3

Elastic wave is one of the most useful tools for non-destructive tests in nuclear power plants. Since the elastic properties are indispensable for analyzing the behaviors of elastic waves, they should be predetermined within an acceptable accuracy. Nuclear power plants are exposed to harsh environmental conditions and hence the structures are degraded. It means that the Young’s modulus becomes unreliable and in-situ measurement of Young’s modulus is required from an engineering point of view. Young’s modulus is estimated from the group velocity of propagating waves. Because the flexural wave of a plate is inherently dispersive, the group velocity is not clearly evaluated in temporal signal analysis. In order to overcome such ambiguity in estimation of group velocity, Wigner-Ville distribution as the time-frequency analysis technique was proposed and utilized. To verify the proposed method, experiments for steel and acryl plates were performed with accelerometers. The results show good estimation of the Young’s modulus of two plates.

위암의 연령에 따른 차이

김영재(Young Jae Kim),이영철(Young Chul Rhee),이만길(man Kill Lee),차호(Ho Cha),정영채(Young Chae Jung) 대한소화기학회 1987 대한소화기학회지 Vol.19 No.1

N/A Comparative analytic review on clinical, endoscopic and histopathological findings was done in 13 cases of young age (under 29), 446 cases of mid age (30~69) and 39 cases of old age (above 70) stomach cancer who were visited Department of Internal Medicine of Masan Koryo General Hospital from March 1981 to July 1985. The following results were obtained: The peak of age incidence was the 5th decade amounting to 36.8%. The ratio between male and female was 2.6:1. The main chief complaint of each group was epigastric pain and it was followed by epigastric fullness. The most patient had the duration of symptom from 3 months to 6 months. For old-age group, mid-age group, major site of lesion in the antrum, meanwhile body for young-age group. The most frequent type of gastric cancer was type III in each group by Borrmanns classification. For each group, adenocarcinoma was major cases in the view of histopathological findings, and incidence of well differentiated type adenocarcinoma were lower in young-age group than others.

청소년 인터넷 중독 검사 방법의 통계적 고찰 및 개선 -Young의 척도를 중심으로

박찬정 ( Chan Jung Park ),김형철 ( Hyung Chul Kim ),고영민 ( Young Min Ko ),현정석 ( Jung Suk Hyun ),김철민 ( Cheol Min Kim ) 한국컴퓨터교육학회 2010 컴퓨터교육학회 논문지 Vol.13 No.4

국내외에서 이루어진 기존의 인터넷 중독 검사에 대한 연구는 다양하며 방대하지만, 대부분의 연구가 중독도 검사를 위한 항목추출이거나 항목들을 이용한 중독도 분석이었지 항목간의 분석을 통한 차별화는 이루어지지 않았다. 본 논문에서는 리즈렐과 데이터마이닝 기법을 이용하여 Young의 인터넷 중독 검사방법을 고찰하고 문제점을 지적한 후, 검사 방법에 대한 대안을 제안한다. 이를 위해 Young의 척도를 이용하여 청소년 440명을 대상으로 설문을 실시하고, 요인분석을 통해 Young 척도의 문제점을 분석한다. 또한, 데이터 마이닝 알고리즘인 J48 및 PART를 이용하여 설문문항들 중에서 인터넷 중독도를 구분 지을 수 있는 항목들을 선별하고 이를 기반으로 인터넷 중독 학생들을 진단하고 처방하는데 활용하는 방법을 제안한다. So far, the researches about the Internet addiction testing are diverse and enormous. However, since the testing factors have the same importance, there is no discrimination among the factors. In our paper, we analyze the problems of the existing researches by using Lisrel and data mining algorithms. Next, we propose an alternative for the Internet addiction testing. In order to accomplish these, we make an questionnaire consisted of Young`s test and then, we asked to 440 primary and secondary school students. In addition, we analyzed the problems of Young`s test with factor analysis and then, we distinguish more important items from others with J48 and PART. Finally, based on this analysis, we propose a method to diagnose addicted students and prescribe them.

가속도계를 이용한 재료의 영계수 측정방법

손창호(Sohn, Chang-Ho),박진호(Park, Jin-Ho),윤두병(Yoon, Doo-Byung),정의필(Chong, Ui-Pil),최영철(Choi, Young-Chul) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.11

For the description of the elastic properties of linear objects a convenient parameter is the ratio of the stress to the strain, a parameter called the Young's modulus of the material. Young's modulus can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. Conventional method for estimating Young's modulus measured the ratio of stress to corresponding strain below the proportional limit of a material using a tensile testing machine. But the method needs precision specimens and expensive equipment. In this paper, we proposed method for estimating Young's modulus using accelerometer. The basic idea comes from that the wave velocity is different as the Young's modulus. To obtain Young's modulus, a group velocity is obtained. It is difficult to measure group velocity. This is because plate medium has a dispersive characteristics which has different wave speed as frequency. In this paper, we used Wigner-Ville distribution to measure group velocity. To verify the proposed method, steel and acryl plate experiments have been performed. Experimental results show that the proposed method is powerful for estimating Young's modulus.

유방의 과립세포종양 1예: 증례보고

민인철, 유근수, 선우영, 윤효영, 송영진 충북대학교 의과대학 충북대학교 의학연구소 2013 忠北醫大學術誌 Vol.23 No.2

유방의 과립세포종양은 슈반세포에서 기원하는 아주 드문 질환이다. 대부분의 환자들은통증을동반 하 지 않는 경성의 유방 멍울을 주소로 내원하게 된다. 따라서 이학적 진찰상 유방암과의 감별이 필요하 다. 유방의 과립세포종양은 임상적으로 유방암과 매우 유사하지만, 98%에서 양성 소견을 보인다. 일 반적인 유방촬영술 및 유방초음파 상에서는 종양 특이적인 소견을 보이지 않으며, 오직 조직생검술을 통한 조직학적, 면연화학적 검사만이 병변을 확진 하는 방법이 된다. 51세 여자 환자가 유방에 만져 지는 멍울을 주소로 외래를 방문하였다. 이학적 검사 상, 좌측 중간외측 유방에 멍울이 만져졌으며, 대흉근 및 주변조직과 고착 되어있는 소견을 보였다. 유방단순촬영 상 좌외측 유방에 비대칭성이 보 였다. 유방 초음파상 1cm크기의 유방 뒤 지방층을 침범하는 종괴가 보였다. 중심 침 조직검사 상 유 방의 과립종양세포 소견을 보였으며, 조직 절제 생검으로 확진 하였다. 임상적으로 유방암과 많이 혼 돈되는 과립세포종양 1예를 보고하고자 한다.

성인의 급성 설사에 대한 로페라미드 옥사이드의 효과: 위약과의 무작위 이중 맹검 비교 다시설 시험

박영태,정희진,박중원,이계희,김나영,임선희,윤병철,한동수,이오영 大韓消化器病學會 1998 大韓消化器病學會誌 Vol.31 No.5

영화에 있어서 표현의 자유와 제한상영관의 도입

양영철 현대사진영상학회 2002 현대사진영상학회논문집 Vol.5 No.-

Freedom of Expression and Restricted Film Theatre Yang, Young-chul The purpose of this essay is to investigate whether or not the Film Rating system in Korea is violating the constitutional Freedom of Expression. Since Movies are a form of mass-communicative art, Freedom of Expression should be applied to it even though it is a form of entertainment and industry as well. But under our rating system, certain films are limited of the possibility to be showed to the mass. Films of grade R(Restricted Permission-not the same as R of the American rating system) only can be showed at Restricted Film theatres and these theatres are not existed yet. The current Motion Picture Act authorizes the Rating Board to decide Whether or not a grown up person can watch a certain movie and it's explicitly unconstitutional. So the Board should classify only the movies which they are able to, and those movies which they do not are permitted to be shown at the theatres for 'No rating Movies'

인터넷 중독 청소년들의 정신병리 및 대처 방식

안영균(Young Kyun Ahn),신영철(Young Chul Shin),고복자(Bok Ja Koh),심진현(Jin Hyun Shim),김범조(Bum Jo Kim),이승민(Seung Min Lee),이길홍(Kil Hong Lee) 한국중독정신의학회 2005 중독정신의학 Vol.9 No.1

This study was conducted to investigate the differences in psychopathology and coping strategies among internet addictors, over users and non addictors in high school students. Subjects were 273 high school students in Seoul city. Self rating questionnaires included demographic data, Young’s Internet Addiction Scale, SCL-90-R, Beck Depression Inventory, Spielberger State-Trait Anxiety Inventory, and The Way of Coping Strategy. Subjects were classified into 3 groups (addiction, over use, non addiction) by Internet Addiction Scale score. Prevalence of internet addiction was 4.3% and male adolescents were more addictive than female. Students who were mainly involved with internet chatting or game showed higher internet addiction score. The addiction group and over use group showed higher level of somatization, obsession, interpersonal sensitivity, depression, anxiety, hostility, and paranoia than non-addicted group. Addiction group and over use group used passive coping strategies more frequently in the stressful situation than nonaddicted group. Also, the regression analysis for finding out causal factors that predicts internet addiction showed that emotion relieving strategy were important variable which predict internet addiction. Interpersonal sensitivity and emotion relieving coping strategy was important to predict addiction. This study showed that problematic internet use was closely associated with psychopathology and psychiatric comorbidity. And high interpersonal sensitivity and emotion relieving coping strategy were related with internet addiction in adolescence.

POE Formula를 이용한 모듈러 로봇 좌표독립 모델링

조영진,여인철,김영탁,안영명 중앙대학교 생산공학연구소 1999 생산공학연구소 논문집 Vol.8 No.2

모듈러 로봇은 우주, 건설산업, 원자력발전 및 여러 소비제품 생산분야에서 이미 오래 전부터 채용되어온 모듈러의 개념을 로봇에 적용한 것이다. 미리 규격화된 모듈을 응용작업 대상에 따라 효과적인 로봇구조로 조립하므로써 작업효율이 높은 로봇을 구성할 수 있게 한다. 따라서 모듈러로봇은 미리 정해진 한가지 로봇구조를 가지고 있지 않으며 더불어 관절간의 관계인 링크 파라미터도 정해져 있지 않다. 즉 로봇의 구조가 결정되어야 비로소 링크파라미터가 결정된다. 로봇구조에 따라 링크파마미터가 다르게 되고 모델링도 달라지는데 로봇제어를 위해서 그 때 마다 모델링을 해야 하는 것은 매우 번거롭고 시간과 노력을 요하는 일이다. 따라서 로봇구조에 상관없이 자동적으로 모델링이 가능한 수법의 개발이 요구된다. 본 연구에서는 로봇의 모델링 기법으로써 계산량이나 컴팩트한 형태 때문에 최근에 많은 주목을 받고 있는 POE formula를 모듈러 로봇에 적용하여 로봇의 구조가 바뀌더라도 자동으로 모델링이 될 수 있는 방법에 대해 기술한다. Modularity in robotics is an extension of the general concept of modular system design which has been previously used in many areas as diverse as space applications, construction industry, nuclear power plants, and many consumer products. Modularity offers quick assembly of pre-constructed modules into robots which may have different kinematic configuration as given tasks. Thus modular robots have no pre-defined link and joint parameters, i.e., the link lengths, offsets, and joint twists. The kinematic model of a modular robot will be established only when its assembly configuration is determined. Therefore, a configuration independent kinematic and dynamic modeling techniques are necessary for the modular robots. In this paper, the configuration independent kinematic and dynamic modeling techniques for the modular robot is described. Product of exponentials (POE) formula is used for the modeling.