비선형 유한요소해석 프로그램을 이용한 차체 구조물의 동강성 및 정강성 해석

김성현(Sunghyun Kim),김형일(Hyungil Kim),변형배(Hyungbai Byun),김동석(Dongseok Kim),이용훈(Yonghoon Lee),김일환(Ilhwan Kim),허승진(Seung Jin Heo),임홍재(Hong Jae Yim) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

In this study, dynamic stiffness analysis and static stiffness analysis were conducted by using nonlinear finite element analysis program and linear finite element analysis respectively to compare the results and to confirm reliability about results of nonlinear finite element analysis program. First, dynamic stiffness analysis has been performed on side out panel, crash box, sub-frame and BIW(Body In White) that has been connected with front bumper, rear bumper and sub-frame. Second, static stiffness analysis has been conducted on crash box and hood that has been modeled with spot weld elements and rigid body elements. Consequently, differences of dynamic and static stiffness analysis results through nonlinear finite element analysis program and linear finite element analysis were below 6 % but difference was more than 6 % as to dynamic stiffness of BIW.

합성곱신경망(CNN)을 이용한 SA 용접부 결함 검출

김성현(Sunghyun Kim),유회수(Hoi-Soo Ryoo),이상아(Sanga Lee) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

일반 균형 동학 모형을 이용한 국가 채무증가의 거시 경제적 영향 분석

김성현(Sunghyun Kim),김소영(Soyoung Kim) 한국계량경제학회 2013 JOURNAL OF ECONOMIC THEORY AND ECONOMETRICS Vol.24 No.4

본 연구는 정부부문을 포함한 일반균형 동학모형을 이용하여 정부소비와 투자지출의 증가,소비 및 소득세율의 감소 등으로 인한 국가채무의 증가가 중장기적으로 경제에 미치는 영향을 분석하였다. 정부 지출증가에 따른 국가채무의 증가는 다음의 경로로 경제에 부(-)의 영향을 미칠 수 있다. 첫째, 재정적자로 인한 유동성 할증은 이자율을 상승시키고 투자를 구축시켜 중장기적으로 생산량을 감소시키고 경제의 후생을 악화시킬 수 있다. 시뮬레이션에 따르면 0.5%의 이자율 상승을 일으키는 정부지출의 증가는 (GDP대비 10%) 장기적으로 생산량을 4.7% 가량 감소시킬 수 있다. 둘째, 정부투자지출이 공공자본을 형성하는 경우 정부투자지출의 증가는 단기적으로 민간자본을 대체하게 되고 소비와 후생을 감소시킬 수 있다. 셋째, 공공자본 축적에 도움이 안되고 가계의 효용에 직접적으로 영향을 미치지 못하는 정부 지출의 증가는 소비를 감소시키고 노동 투입을 증가시켜 경제 전체의 후생을 감소시킬 수 있다. 하지만 세율의 감소에 의한 국가 채무의 증가는 일반적으로 정부 지출에 의한 국가 채무 증가의 경우보다 정(+)의효과가 크다. This paper uses a dynamic general equilibrium model with government sector and analyzes short-run and long-run macroeconomic effects of government debt caused by either increases in government spending or decreases in various tax rates. The simulation results suggest several channels that government debt can negatively affect the economy: First, liquidity premium caused by an increase in government debt increases interest rate and decreases investment, and therefore lowers output and welfare in the long run. This is the most significant negative channel in this model. Second, when government spending builds up public capital, an increase in government debt temporarily crowds out private sector capital, which reduces output and welfare in the short run. Third, when government spending affects neither public sector capital nor household utility, an increase in government debt reduces consumption and increases labor input, thereby reducing social welfare. In addition, if the increase in government debt is caused by a decrease in tax rates, positive effects can dominate.

암반파쇄용 진동리퍼의 사용시간 확인을 위한 IT 융합 기초 연구

김성현(SungHyun Kim),이한권(HanGwon Lee),박정열(JungYeol Park),박종원(JongWon Park) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.IT융합 No.-

노후 아파트 단지의 범죄예방환경설계에 관한 평가와 적용 방안 연구

김성현(Kim, Sunghyun),변기동(Byun, Gidong),김석경(Kim, Sukkyoung),하미경(Ha, Mikyoung) 대한건축학회 2020 대한건축학회 학술발표대회 논문집 Vol.40 No.2

Mokdong Apartment, which was built in the 1980s, has been raising voices for reconstruction due to the aging of buildings for nearly 40 years, but it has become difficult for Mokdong apartments to receive a rating that can be rebuilt due to the increased proportion of structural safety based on the criteria for reconstruction safety diagnosis. at this time, facilities around Mokdong apartments do not have any significant problems, but it is necessary to prevent social isolation and rising crime rates that may arise from the aging of buildings. Therefore, the purpose of this study is to consider the application of CPTED to reduce the possibility of social isolation and increase in apartment crime rates caused by the aging of Mokdong apartments built in the 1980s.

비행 학업중단 청소년들의 관용성과 자아존중감 간의 관계

김성현 ( Kim Sunghyun ) 인하대학교 교육연구소 2016 교육문화연구 Vol.22 No.2

이 연구에서는 학업중단 학생의 지속적인 증가 현상에 주목하고 비행 학업중단을 줄이기 위한 교육적 처방을 위한 탐색과정으로 관용성과 자아존중감 간의 관계를 규명하고자 한다. 본 연구의 대상은 G시에서 비행 학업중단중인 중, 고등학생 58명이었다. 본 연구의 결과를 살펴보면 첫째, 비행 학업중단 청소년들의 성별에 따른 관용성 전체 및 하위영역에서 유의미한 차이를 보이지 않았다. 둘째, 비행 학업중단 청소년들은 자아존중감과 관용성이 유의미한 상관이 있었다. 셋째, 비행 학업중단 청소년들의 자아존중감이 관용성에 정적으로 유의한 영향을 미치는 것으로 나타났다. 이 연구를 통해 비행 학업중단 요인과 방지대책을 마련하는 데 시사점을 제공하였고, 이를 통해 교육현장에서 관용성 증진교육과 자아존중감 증진에 힘써야 한다는 사실을 확인하였다. The purpose of this study was to examine the relationship between the tolerance and self-esteem of delinquent drop-out youths in an effort reduce the number of delinquent drop-out youths, as there has been a steady increase in the number of school drop out youths. The subjects in this study were 58 selected delinquents who dropped out of secondary school in an urban community. The findings of the study were as follows: First, the delinquent drop-out youths were significantly less tolerant. As for comparison by the grade of school, the middle school students were significantly less tolerant than the high school students. Second, the delinquent drop-out youths had a significantly lower self-esteem. As to comparison by the grade of school, there were no significant differences between the middle school students and the high school students. This study is expected to give a clue about what makes students drop-out of school by committing a misdeed and how to prevent it, and every school should try to boost tolerance and self- esteem.

차량의 부분구조 모델을 이용한 협력업체 범퍼성능 평가 방법

김성현(Sunghyun Kim),김형일(Hyungil Kim) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

In general, the role of the low-speed vehicle bumper is to absorb the impact during a collision and protect the vehicle with its occupants. In order to evaluate the efficiency of the bumper, each country must follow some domestic and International low-speed bumper impact standards and specifications to determine damaged regions. But it is only a consultation or confirmation and not actually the regulation of the efficiency of the bumper. Most automobiles evaluate the balance of the development stage of the bumper with the resultant price of completion which should not yield to a many difference. In this paper, we propose to automobiles possible conditions for a impact test of the low-speed vehicle bumper with great value results.

전후륜 독립구동 전기자동차의 제동력 분배 최적화

김성현(Sunghyun Kim),권기한(Kihan Kwon),민승재(Seungjae Min) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

To extend the driving range of electric vehicles, various studies to maximize the driving efficiency such as optimization of driving force distribution are performed. Because an electric vehicle can recover energy through regenerative braking, it can be optimized to minimize energy consumption. However, because braking is directly related to the safety, it is required to achieve stable braking by distributing torque to the front and rear wheels. The maximum torque of the motor may not satisfy the required braking force, so hydraulic braking force can be required. In this study, the regenerative braking force distribution is optimized within the range of securing the braking stability of the vehicle by considering ideal braking force distribution and ECE regulations for braking. Modeling and simulation of front and rear axle independently driven electric vehicles is carried out, and the driving force and braking force are optimized. It is designed to satisfy the required braking force by the regenerative braking of the motor and support of the mechanical braking when needed. Through the WLTP cycle simulation, it is confirmed that the SOC consumption is decreased compared with the braking force distribution based on the I-Curve.

부모-자녀 간 의사소통 훈련이 중학생의 또래관계기술 및 학교적응에 미치는 효과

김성현(Kim, Sunghyun),백현옥(Baek, Hyunok) 한국학부모학회 2021 학부모연구 Vol.8 No.3

이 연구에서는 부모-자녀 간 의사소통 훈련이 중학생의 또래관계기술 및 학교적응에 미치는 효과를 알아보기 위해 연구가 진행되었다. 본 연구에서는 다음과 같이 연구문제를 설정하였다. 첫째, 부모-자녀 간 의사소통 훈련은 중학생의 또래관계기술에 어떠한 효과 있는가이었고 둘째, 부모-자녀 간 의사소통 훈련은 중학생의 학교적응에 어떠한 효과가 있는가이었다. 본 연구에서의 대상은 G시 소재 중학생 학부모 22명과 중학생 22명이었다. 조사도구로는 또래관계기술척도와 학교적응척도를 사용하였고, 분석방법으로는 빈도, t-검증, 공변량분석(ANCOVA)을 실시하였다. 본 연구의 결과를 살펴보면 첫째, 부모-자녀 간 의사소통 훈련이 중학생의 또래관계기술을 증진시키는 것으로 나타났다. 둘째, 부모-자녀 간 의사소통 훈련은 중학생의 학교적응력을 증진시키는 것으로 나타났다. 이 연구를 통해 부모-자녀 간 의사소통 훈련과 중학생의 또래관계기술, 학교적응과 관련하여 교육현장에서의 시사점을 제공한다고 볼 수 있다. The study was conducted to investigate the effect of parent-child communication training on peer relationship skills and school adaptation of middle school students. The research questions were set as follows. First, what effect did parent-child communication training have on the peer relationship skills of middle school students, and second, what effect did parent-child communication training have on middle school students school adaptation. The subjects of this study were 22 parents of middle school students in G city and 22 middle school students. The peer relationship skill scale and school adaptation scale were used as research tools, and frequency, t-test, and covariate analysis (ANCOVA) were performed as analysis methods. Looking at the results of this study, it was found that parent-child communication training improves the peer relationship skills of middle school students. Second, parent-child communication training was found to enhance middle school students ability to adapt to school. It can be seen that the results of this study provide implications in the educational field regarding communication training between parents and children, peer relationship skills of middle school students, and school adaptation.

<범금팔조> 비판 과정의 학습 내용 구조화 가능성

金聖玹(Kim, Sunghyun) 역사교육연구회 2022 歷史敎育 Vol.161 No.-

This article aims to discuss the possibility of structuring the Code of Eight Prohibitions of Gojoseon(<Beomgeum-Paljo>) as a learning content focusing on the process of critique of historical materials, and to present a case in which students can experience critical thinking and reading. History classes using historical materials have gained a lot of attention, and since the 7th Curriculum, <Beomgeum-Paljo> has been used as a material for inquiry activities. However, despite the discussion that there is a need to enhance students’ critical thinking ability through learning with historical materials, what is required through the historical learning with <Beomgeum-Paljo> is still only at the level of acquiring the contents that have been described in textbooks. Considering the necessity of presenting an inquiry task that induces thinking by reading historical materials so that students can practice reading historical materials critically, <Beomgeum-Paljo> also needs to be used for students to experience critical reading. In particular, <Beomgeum-Paljo> provides an opportunity for students to capture the characteristic of history that past record does not correspond directly to the past realities.