부분강절 뼈대구조의 비탄성 좌굴해석

민병철,Min, Byoung Cheol 한국강구조학회 2014 韓國鋼構造學會 論文集 Vol.26 No.3

본 연구에서는 부분강절 뼈대구조물의 비탄성 좌굴해석기법을 제시하기 위하여, 이전의 연구[16]에서 제시되었던 부분강절 뼈대구조의 엄밀한 강도행렬과 선형해석을 위한 탄성 및 기하학적 강도행렬을 도입하고 비탄성 좌굴해석을 위해 도로교시방서의 극한내하력 기준과 EF법을 이용하여 부분강절 뼈대구조의 비탄성 좌굴해석 프로그램을 새롭게 개발하였다. 본 연구에서 제시한 부분강절 뼈대구조의 접선강도행렬은 안정함수를 사용함에 따라 부재 당 하나의 요소만으로 정확한 비탄성 좌굴해석 결과를 얻을 수 있으며 고유벡터를 이용하여 비탄성 좌굴형상을 얻을 수 있는 장점을 갖는다. 또한, 엄밀한 접선강도행렬에 대해 Taylor 전개를 수행하여 4차항까지 고려함으로서 탄성 강도행렬과 기하학적 강도행렬을 유도하고 선형화된 좌굴해석기법을 제시하였다. 결국, 접선강도행렬을 이용한 비선형 해석프로그램(M1)과 탄성 및 기하학적 강도행렬을 이용한 선형 해석프로그램(M2)이 개발되었으며 이를 이용하여 부분강절로 연결된 뼈대구조물의 비탄성좌굴에 대한 시스템 좌굴하중과 개별부재의 유효좌굴계수를 제시함에 따라 부분강절이 전체 구조계의 좌굴과 개별부재의 유효좌굴길이에 미치는 영향을 다양한 해석예제를 통해 조사하였다. An improved method for evaluating effective buckling length of semi-rigid frame with inelastic behavior is newly proposed. Also, generalized exact tangential stiffness matrix with rotationally semi-rigid connections is adopted in previous studies. Therefore, the system buckling load of structure with inelastic behaviors can be exactly obtained by only one element per one straight member for inelastic problems. And the linearized elastic stiffness matrix and the geometric stiffness matrix of semi-rigid frame are utilized by taking into account 4th terms of taylor series from the exact tangent stiffness matrix. On the other hands, two inelastic analysis programs(M1, M2) are newly formulated. Where, M1 based on exact tangent stiffness matrix is programmed by iterative determinant search method and M2 is using linear algorithm with elastic and geometric matrices. Finally, in order to verify this present theory, various numerical examples are introduced and the effective buckling length of semi-rigid frames with inelastic materials are investigated.

Quad-rotor UAV의 동역학적 모델링과 비행자세 최적화를 위한 PID 제어기 설계

민병철,조찬호,최경민,김동한 경희대학교 경희정보통신 SoC연구소 2008 경희정보통신SOC연구소 논문집 Vol.9 No.-

In this paper, we present a design of quad-rotor aircraft that is a type of unmanned air vehicle (UAV)because of their strong advantages of minimized size and their powerful capabilities for monitoring environment. The nonlinear model of 6 degrees of freedom (6 DOF) quad-rotor aircraft in air is derived on the basis of the Newton-Euler formalism. Because the derived model that comprises translational and rotational subsystems is dynamically unstable, we set on a nonlinear control strategy for the quad-rotor aircraft. The control strategy includes PID controller that is common in the nonlinear control for the translational subsystem and the rotational subsystem of the quad-rotor aircraft. The optimal coefficients of PTD controller are measured by the computer simulation and the results verify the effectiveness of the proposed control strategy for the quad -rotor aircraft. Finally we demonstrate experimentally stability of the small-scale quad-rotor aircraft by using a wireless camera on it to get distinct images of surrounding environment. The manufactured aircraft is equipped with four rotors generating various dynamics, two embedded controllers using PID controller, and a navigation system based on gyro sensors, an accelerometer sensor and an ultrasonic sensor.

비대칭 단면을 갖는 박벽 곡선보의 안정성해석 I: 해석적 방법

민병철,김문영 한국전산구조공학회 1998 전산구조공학 Vol.11 No.4

본 연구에서는 비대칭 박벽단면을 갖는 곡선보의 안정성해석을 수행할 수 있는 이론 및 엄밀해를 제시하기 위하여, 3차원 연속체로부터 유도된 평형방정식으로부터 선형화된 가상일의 원리를 적용하였다. 박벽단면의 구속된 ?(warping)과 곡률효과를 고려하고 유한한 회전각의 2차항을 포함하는 곡선보의 변위장을 도입하여 단면에 대해 적분함으로써 도심축에 대한 박벽 곡선보의 총포텐셜에너지를 유도하였다. 또한, 단순지지되고 일축대칭 단면을 갖는 박벽원형 곡선보의 면내 및 면외좌굴에 대한 엄밀해를 유도하기 위하여, 면내에 대해서는 균일압축을 받는 원형아치의 역대칭 좌굴모드에 대한 좌굴하중을 유도하고 면외좌굴에 대해서는 균일압축 및 순수휨을 받는 아치의 처짐함수를 가정하여 곡선보의 횡좌굴하중에 대한 일반해를 제시하였다.

청소년의 정보통신 윤리의식 수준과 선플활동 경험과의 관계

민병철,오경숙 사단법인 인문사회과학기술융합학회 2019 예술인문사회융합멀티미디어논문지 Vol.9 No.8

본 연구는 청소년의 정보통신 윤리교육의 방법으로 선플달기 캠페인은 물론 다양한 청소년 체험활동을 통한 교육방법을 모색하는데 그 목적을 두고 청소년들의 정보통신 윤리의식 수준은 어떠하며, 이는 성별과 선플활동 경험에 따른 청소년의 정보통신 윤리의식 수준을 분석하였다. 이를 위해 전국의 초, 중, 고등학교에 재학 중인 2231명의 청소년을 연구대상으로 하였다. 수집된 자료는 SPSS 21.0프로그램을 사용하여 t검증과 일원변량 분석을 실시하였다. 본 연구에서는 정보통신 윤리의식을 존중, 정의, 예절, 자율, 책임의 5개 요인으로 설명하였다. 연구결과, 청소년의 정보통신 윤리의식은 매우 높은 수준이었고, 여학생이 남학생보다 정보통신 윤리의식 수준이 높았다. 6개월 이상의 선플활동 경험을 한 청소년들의 정보통신 윤리의식이 높았으며, 특히 ‘정의’, ‘예절’, ‘책임’에서 선플 활동 경험이 많을수록 높은 결과를 나타냈다. 본 연구의 결과는 청소년의 정보통신 윤리의식 교육에 있어 선플활동과 같은 학생 참여 프로그램이 정보통신 윤리의식을 높여줄 수 있다는 시사점을 도출하였다. The following study investigates the level of ethical sense amongst teenagers regarding information and communications, and how differences are constructed depending on gender and experiences on commenting activities. In order to do so, 2231 students in elementary, middle, and high schools nationwide took part in the study. The gathered information was analyzed with the t-test and one way analysis of variance was conducted through the SPSS 21.0 program. The study further explained ethical senses of information and communication with 5 different factors: respect, justice, manners, autonomy, and responsibility. The analysis showed that ethical senses of communication and information amongst teenagers were high, and female students tend to have a higher level of ethical sense than male students. Students that had the experience of writing positive comments for more than 6 months tend to have higher senses, and in particular, the more experience of writing positive comments in the areas of ‘justice’, ‘manners’, and ‘responsibility’, results showed higher ethical senses. The results of the following study drew out implications that student participatory programs such as writing positive comments can increase ethical senses amongst teenagers in the education of communication and information ethical senses of students.

비대칭 단면을 갖는 박벽 곡선보의 안정성해석 II : 수치적 방법

민병철,김문영 한국전산구조공학회 1998 전산구조공학 Vol.11 No.4

본 논문에서는 연계논문에서 제시한 비대칭 박벽단면을 갖는 곡선보 및 직선보 이론을 토대로, 곡선보 요소 및 직선보 요소를 개발하고 이를 이용한 유한요소 정식화 과정을 제시한다. 유한요소 정식화 과정에서는 요소의 변위장을 도심에 대하여 정의한 후, 요소 변위벡터에 관한 3차의 Hermitian 다항식을 형상함수로 사용하고 가우스 적분을 행함으로써 탄성 강도행렬 및 기하학적 강도행렬을 산정하였다. 얻어진 강도행렬을 이용하여 고유치 문제를 계산함으로써 좌굴하중을 계산하였으며 다양한 해석 예제를 통하여 다른 연구자들의 해석 결과와 비교 검토함으로써 본 연구의 타당성과 우수성을 입증하고자 한다.

Organic dyes consisting of Thieno thiophene for DSSC s

민병철,김창주,장석훈,신용태,김철희 한국고분자학회 2010 한국고분자학회 학술대회 연구논문 초록집 Vol.2010 No.4

트레드밀 런닝과 물속 걷기 및 수영의 유산소 운동이 비만여성의 신체구성 및 혈중 지질농도 변화에 미치는 영향

민병철,홍창배,김기진 대구경북체육학회 2005 체육연구 Vol.1 No.1

UV 조사에 의한 방향족오염물의 분해

민병철,김종향,김병관 ( Byoung Chul Min,Jong Hyang Kim,Byung Kwan Kim ) 한국공업화학회 1997 공업화학 Vol.8 No.3

방향족 오염물을 UV산화- 고도산화처리기술로 처리할 때, 여러 가지 반응조건에 따른 분해효율에 대해 고찰하였다. 벤젠 50pmm, 에틸벤젠 150ppm, 크실렌 250ppm을 각각 초기농도로하여 UV조사 하에서 시간변화에 따른 분해실험을 행한 결과, 반응 1시간 후 약 95% 이상의 분해율을 나타내었으나, 톨루엔의 경우에는 43%의 분해율을 보였다. 단일성분이 혼합성분에서 보다 분해가 좋았으며, pH변화에서는 벤젠은 pH변화에 관계없이 분해가 잘되었으며, 에틸벤젠 92%(pH 4.0), 90%(pH 6.4), 91%(pH 10.0), 크실렌 95%(pH 4.0), 90%(pH 6.4), 92%(pH 10.0), 그러나 톨루엔은 80%(pH 4.0), 43%(pH 6.4), 70%(pH 10.0)의 분해율을 나타내었다. 방향족 오염물의 TOC 감소는 에틸벤젠을 제외하고는 유사 1차 반응속도식에 일치하였으며, 이로부터 속도상수를 결정할 수 있었다. Aromatic pollutants(benzene, toluene, ethylbenzene and xylenes) were photodegraded by using a UV oxidation and the rates of degradation were investigated under various reaction conditions. Each of the solution containing 50 ppm benzene, 150 ppm ethylbenzene and 250 ppm xylenes was found UV-photodegraded over 90% in 1 hour of reaction time, wheras the only was 43% of degradation was obtained with 350 ppm toluene solution. A single component solution was more degradable than a mixed component solution and benzene was almost photodegraded at a pH 4.0, 6.4 and 10.0 after reaction time is 1 hr, ehtylbenzene was photodegraded about 92%(pH 4.0), 90%(pH 6.4) and 91%(pH 10.0), xylenes was photodegraded about 95%(pH 4.0), 90%(pH 6.4) and 92%(pH 10.0), but toluene was photodegraded about 80%(pH 40), 43%(pH 6.4) and 70%(pH 10.0), respectively. Kinetics studies show that the rate of decay in TOC(total organic carbon) were pseudo first-order rate except ethylbenzene, and then we could evaluate mineralization rate constants(k) of aromatics.

셀프리더십의 영향요인과 효과: 의료기관 조직구성원을 중심으로

민병철,임성원,김한결,이현실 한국보건행정학회 2013 보건행정학회지 Vol.23 No.1

The purpose of this empirical study is to investigate the factors of self-leadership depending on individual characteristics, job characteristics, and qualities of leader-member exchange. Additionally, this study aims to discover the effect of self-leadership’s outcome factors on organizational citizenship behavior and innovative activities. In order to verify research model and hypothesis, questionnaires were collected from department members working at general hospitals, hospitals, and clinics in metropolitan area of Seoul, which were 85 departments and 344 respondents. Collected data were analyzed with SPSS ver. 19.0 and Amos ver. 18.0 statistical package using Structural Equation Model. The results of the analysis showed that both individual characteristics and job characteristics have significant positive effect on self-leadership. Also, self-leadership had significant positive relationship on innovative action and organizational citizenship behavior. The implications of this study are as follow. First, this study empirically explained how self-leadership is applied in healthcare organizations. Second, it verified the relationship between causal factors and outcome factors of self-leadership. Also, prior researches of self-leadership have been conducted on business companies, but this study explored self-leadership at healthcare organizations, which increased external validity. Nowadays, many people are interested in the effect of leadership in order to overcome issues coming from enlarged organizations and to improve performance. Self-leadership will contribute to maximizing voluntary efforts of human resources and performance in a rapidly changing healthcare industry.

위선암에서 p53과 P-glycoprotein의 분포에 관한 연구

김대중,김의한,강상균,양승하,민병철 순천향의학연구소 1996 Journal of Soonchunhyang Medical Science Vol.2 No.1

Gastric adenocarcinoma express many oncogenes, such as p53, c-erbB, k-sam, etc. The p53 especially acts as tumor suppressor in normal tissue and various mutational changes. of p53 are known as doing important role in carcinogenesis of gastric adenocarcinoma. P-glycoprotein, as a pleotrophic membrane transport protein, shows specific distribution in many normal tissues and malignant tumors. This protein, produced by MDR gene, shows multidrug resistance to anticancer drug by pumping out intracellular drug. resulting in resistance to chemotherapeutics. The expression of p53 and P-glycoprotein according to clincopathologic findings in gastric adenocarcinoma has been studied, even though their results are controversial. To observe the relationship between both antigens and clinicopathologic findings of gastric adenocarcinoma. we were analysesed 40 cases gastric adenocarcinoma then processed for immunohistochemical stain by SLAB method using p53 and JSB-1 monoclonal antibodies. The results were as followings: 1) The p53 and P-glycoprotein showed positive in 20 cases(50%) and 21 cases(52.5%) of 40 cases respectively, and 10 cases(25%) showed positive reaction to both antigens. 2) p53 revealed higher positive rate in intestinal type(54.6%), differentiated form(57.1%), advanced form(58.1%) compared to diffuse type(28.6%), poorly differentiated form(42.1%), early cancer(22.2%), but no difference according to age, sex, lymphatic metastasis and signet ring cell within tumor. 3) P-glycoprotein revealed higher positive rate in interstinal type(54.6%), differentiated form(61.9%), advanced form(58.1%), absence of signet ring cell (63.3%) compared to diffuse type (28.6%), poorly differentiated form (36.8%), early cancer(33.3%), presence of signet ring cell(20.0%), but no difference according to sex, age, lymphatic metastasis. 4) Positive rate in intestinal type, differentiated form, advanced form, and presence of signet ring cells in gastric adenocarcinoma showing both positive reaction of p53 and P-glycoprotein, are higher, but no difference according to age, sex, lymphatic metastasis. 5) In noneoplastic mucosa adjacent to cancer, p53 revealed negative reaction in all cases. P-glycoprotein showed positive reaction in all metaplastic glands 33 cases and parietal cells 17 cases, and in 16 cases(40%) of 40 cases of luminal surface and gastric glandular epthelium, and showed negative reaction in all 12 cases of chief cell. Above results revealed that positive rates of p53 and P-glycoprotein in gastric adenocarcinoma are almost same and there is no relationships between both antigens. Both antigens showed simillar high positive rate in intestinal type, differentiated form and advanced form, indicating association with these clinicopathologic findings.