레이저/아크 하이브리드용접기술의 최신 동향

김영식,길상철,Kim, Youngsik,Kil, Sangcheol 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.2

The laser/arc hybrid welding process is a new process combining the laser beam and the arc as welding heat source. The laser beam and arc influence and assist one another. By application of hybrid welding, synergistic effects are achievable, and disadvantage of the respective processes can be compensated. The laser-arc hybrid welding process has good potential to extend the field of applications of laser technology, and provide significant improvements in weld quality and process efficiency in manufacturing applications. This review analyses the recent advances in the fundamental understanding of hybrid welding processes using the works of the data base of Web of Science (SCI-Expanded) since the 2000 year. The research activity on the hybrid welding has been become more actively since 2006, especially in China, presenting the most research papers in the world. Since the hybrid welding process was adopted in manufacturing of the automobile in Europe in the early of 2000's, its adopting is widely expanded in the field of manufacturing of automobile, ship building, steel construction and the other various industry. The hybrid welding process is expected to advance toward higher productivity, higher precision, higher reliability through the mixing of high power and flexible fiber laser or disk laser and digitalized pulsed arc source.

해상풍력 발전설비의 고능률 용접기술

김영식,길상철,Kim, Youngsik,Kil, Sangcheol 대한용접접합학회 2015 대한용접·접합학회지 Vol.33 No.3

The offshore wind power plants are watched as a new market to accomplish the needed energy, bringing technical and economical challenges. Advanced countries in the field of wind industry are now appling the 600 MPa, 150~200 mm thick high strength steel to offshore wind power plants. Moreover, the high efficient welding methods which is weldable ultra tick high strength steel with 1 pass welding are developed and applied in manufacturing the offshore wind tower. This article deals with the present world wide status of offshore power plants and the tendency of the development of high efficient welding technology for constructing the offshore wind tower. This article intends to offer the materials for development and raising of the domestic offshore wind power technology.

투르크메니스탄의 경제발전과 에너지프로젝트

김영식(Kim, Youngsik) 한국슬라브유라시아학회 2015 슬라브학보 Vol.30 No.2

Much attention is given to the gas industry, oil complex and development of the resource base in the gas and energy complex. The aim of the report is to provide the reader with some material on indicators of strategic development of gas and energy complex, indicators of strategic development of the oil complex, forecasted fuel and energy balance of Turkmenistan, forecast of the required capital investments into the development of the gas and energy complex and energy supply of Turkmenistan’s economy for the period up to 2020. The Strategy includes the following: the current results of the Energy Strategy of Turkmenistan for the period up to 2020 realization and goods and objectives of the Strategy; the main trends and forecasts of the country socio-economic development, and of the interaction between the economy and energy sector; the prospects of supply for China’s energy; the main provisions of the state energy policy and its most important elements; the development prospects of the Turkmenistan gas and energy complex; the expected results and implementation system of the Strategy.

실내 3D 게임 장면의 잠재적 가시 집합을 위한 효과적인 하드웨어 압축 구조

김영식(Kim, Youngsik) 한국게임학회 2014 한국게임학회 논문지 Vol.14 No.6

대규모 실내 3D 게임 장면에서 차폐 컬링 정보를 미리 계산하는 잠재적 가시 집합(potentially visible set: PVS)은 데이터를 처리하고 저장해야하는 양이 상당히 크지만 많은 부분이 0으로 표현된다. 본 논문에서는 모바일 환경의 3D 게임 장면 트리 구성 중에 PVS 데이터를 ZRLE (zero run length encoding) 방식으로 압축하는 효과적인 하드웨어 압축 구조를 설계한다. 3D 게임 시뮬레이션을 통하여 제안하는 구조의 PVS 데이터 압축 비율, PVS 컬링과 절두체 컬링에 따른 렌더링 속도 (frame per second: FPS)를 분석하였다. In the large scale indoor 3D game scenes, the data amount of potentially visible set (PVS) which pre-computes the information of occlusion culling can be huge. However, the large part of them can be represented as zero. In this paper, the effective hardware structure is designed, which compresses PVS data as the way of zero run length encoding (ZRLE) during building the scene trees of 3D games in mobile environments. The compression ratio of the proposed structure and the rendering speed (frame per second: FPS) according to both PVS culling and frustum culling are analyzed under 3D game simulations.

인공 신경망을 이용한 자동차 시트 안락성 예측 모델 개발

김영식(YoungSik Kim),강태욱(Taeuk Kang),사성진(Sungjin Sah),김치호(ChiHo Kim),최형연(Hyung Yun Choi) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2007 No.11

탄소강 볼트 체결된 GECM(Graphite Epoxy Composite Material)/Al 판재의 구성 부재의 부식 거동

김영식 ( Youngsik Kim ),박수진 ( Sujin Park ),유영란 ( Youngran Yoo ) 한국부식방식학회(구 한국부식학회) 2012 Corrosion Science and Technology Vol.11 No.6

This work focused on corrosion of carbon steel bolted GECM/AI parts in tap water and NaCl solutions. In tap water and NaCl solutions open circuit potential of GECM and its potentials in series of carbon steel bolt>Ti>Al became active. Regardless of test materials open circuit potentials in tap water were noble and increasing NaCl concentration its potentials became active. Immersion test of single specimen showed that no corrosion occur in Ti and GECM. In tap water carbon steel bolt didn`t show red corrosion product and in chloride solutions corrosion rate in 1% NaCL solution was greater than its rate in 3.5% NaCl solution and red corrosion product in 1% NaCl solution was earlier observed than that in 3.5% NaCl solution. It seems that this behavior would be related to zinc-coatings on the surface of carbon stee l bolt. On the other hand aluminium was corroded in tap water and chloride solutios. Corrosion of aluminium in tap water was due to the presence of chloride ion in tap water by sterilizing process.

용접구조물의 최신 비파괴 검사기술

김영식(Youngsik Kim),길상철(Sangcheol Kil) 대한용접·접합학회 2016 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2016 No.11

조선기자재산업을 혁신하는 새로운 용접기술

김영식(Youngsik Kim) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.10

The welding process is the main assembling method of the marine equipment industry. As the new welding process, the FSW and Laser-arc hybrid welding are now being watched much benefit in various industry. However, the 2 welding processes likely are not so understood in domestic marine equipment industry. The mechanism and benefits of the 2 process are illustrated in this paper.

고교생의 교사 인식 관련 예측 요인 탐색

김영식(Kim, Youngsik),문찬주(Moon, Chanju),박환보(Park, Hwanbo) 한국교원교육학회 2020 한국교원교육연구 Vol.37 No.1

본 연구는 한국교육고용패널Ⅱ 1차년도(2016년) 자료에 대하여 랜덤 포레스트 기법을 활용하여, 고교생의 담임 교사 및 학교 교사들에 대한 인식을 예측하는 요인을 탐색하였다. 또한 모형의 예측성과를 검토함으로써 도출된 랜덤 포레스트의 추정 모형이 적합한 모형임을 확인하고자 하였다. 이와 함께 고교생의 담임 및 학교 교사 인식에 대한 예측력이 상대적으로 높은 주요 변수들을 활용하여 중다회귀분석 모형과 학교 고정효과 모형, 학교 확률효과 모형 분석을 실시함으로써 세 가지 모형 중 담임 교사 및 학교 교사에 대한 인식을 예측하는데 보다 효과적인 모형을 확인하고자 하였다. 분석 결과, 부모의 양육 태도, 학교 내 진로교육·활동에 대한 만족도, 수업태도 및 자존감 등과 같은 학생 개인의 정의적 특성, 담임 선생님이 학생을 대하는 방식 등이 담임 교사 및 학교 교사들에 대한 고교생의 긍정적인 인식에 영향을 미치는 것으로 나타났다. 그리고 담임 교사 인식을 예측하는데 있어서는 확률효과모형이, 학교 교사 인식을 예측하는데 있어서는 고정효과모형이 적절함을 통계적으로 확인하였다. 본 연구는 이상과 같은 분석 결과에 기반하여 교사들에 대한 긍정적인 인식을 제고하기 위한 정책적인 시사점을 제공하였으며, 보다 엄밀한 관련 요인 탐색을 위한 학술적 제언 또한 함께 제공하였다. This study explored factors that predict the perception of high school students on homeroom teachers and school teachers by utilizing the random forest technique for the first year of the Korean Education Employment Panel II (2016) and examined whether the estimated model of the random forest was appropriate. In addition, this study tried to identify more effective models among the three models of the multiple regression model, the fixed-effect model, and the random effect model in predicting the perception of the students. The analysis found that the following variables affected the positive perception of students on homeroom teachers and school teachers: parenting attitude, satisfaction with career education and activities in schools, the affective characteristics of students such as class attitude and self-esteem, and the way homeroom teachers treat their students. It also statistically confirmed that the random effect model was appropriate for predicting the perception of students on homeroom teachers and the fixed effect model was appropriate for predicting the perception of students on school teachers. Based on the results, this study provided policy implications for enhancing students’ positive perception on teachers and also provided academic suggestions for a more rigorous exploration of relevant factors.

공익목적 실현을 위한 경찰 규제개혁(規制改革)에 관한 비판적 고찰

김영식(Kim YoungSik) 한국부패학회 2015 한국부패학회보 Vol.20 No.1

경제적 관점에서의 이원적 규제분류체계와 이에 따른 경찰 규제개혁 추진은 공공의 안녕 과 질서유지 그리고 국민생활의 안전이라는 경찰 행정규제의 공익적 목적이 실현되지 못하고 오히려 반공익적 결과를 초래할 수 있다. 따라서 공익적 목적을 실현할 수 있는 바람직한 경찰규제개혁 추진을 위해서는 첫째, 경찰 행정규제가 추구하는 시민의 안전 확보와 사회질서 유지, 일정한 공동체윤리나 집단적 기대 등의 공익적 성격을 반영할 수 있는 사회적 규제의 다원화가 필요하다. 둘째, 경찰 규제개혁은 규제의 정당성 판단을 통한 규제의 질적 향상을 유도하는 방향으로 추진되어야 한다. 셋째, 경찰 규제개혁은 정책추진 과정에서 피규제자에 의한 규제기관의 포획을 차단해야 한다. The police regulatory reform implemented in the dualistic regulatory classification system of the economic perspective, risks damaging public interests pursued by police regulations like public safety, social order and security, and it could incur bad results in the aspect of public interest. Therefore, the desirable regulatory reform requires first of all the diversification of social regulations that could reflect the character of public interest pursued by police regulations such as public security, social order, community ethics and collective expectations. Second, the police regulatory reform should be initiated in the direction of improving the quality of regulations by judging their legitimacy. Third, the police regulatory reform should prevent the regulatory agency from being captured by the regulatee in policy implementation process.