발포사출성형품의 외관 품질 개선 관한 연구

김동학(Kim Dong-Hak),곽온섭(Kwak On-Sub) 한국산학기술학회 2004 한국산학기술학회 학술대회 Vol.- No.-

본 연구에서는 발포사출성형품의 단점인 외관 품질을 개선하기 위해 순간 금형가열방식인 MmSH(Momentary Mold Surface Heating)을 사용하였다. 또한 발포제의 함량에 따른 발포 체의 구조를 살펴보았다. 일반발포사출과 MmSH방식을 사용 발포사출의 표면거칠기를 비교한 결과 표면이 개선된 것을 볼 수 있었고 발포제의 함량에 따른 발포체의 구조는 함량이 증가함에 따라 중량 감소로 셀 수 증가를 보였지만 어느 한계 이후에서는 영향을 미치지 않는 것으로 보여진다.

Thermoplastic Elastomer (TPE)의 내트래킹성 향상에 관한 연구

김동학(Dong-Hak Kim),이동은(Dong-Eun Lee),이승준(Seung-Jun Lee),박규환(Kyu-Hwan Park) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10

옥외 환경에서 사용할 수 있는 전력 케이블은 다양한 환경 조건에 대해 우수한 내트래킹성을 갖는 것이 필수적이며, 특히, 수분에 의한 침식을 방지하기 위해 본 연구에서는 TPE (Thermoplastic Elastomer) 소재를 적용하여 종래의 XLPE (Cross-linked polyethylene) 소재 대체 가능성을 검증하고자 하였다.

청소년의 태권도수련활동이 학업성취도 및 자아정체감에 미치는 영향

김동학(Dong-Hak Kim) 경희대학교 스포츠과학연구원 2008 태권도과학 Vol.1 No.2

The purpose of the study was to examine the influences of Taekwondo participation on selfidentities and academic achivement of adolescents. Participants for this study were 700 of 17~19 aged adolescents. Of participations valid data were 625. They completed a modified inventory of the self-identities and academic achivement. More details, Self-identities Scale modified Kim(1989), and Academic Achivement Scale modified by Yoo(2000) were using to investigate the purpose of this study. Results were analysed in quantitative approaches. Data were collected through self-administered survey. The most four meaningful results of the study were as follows; First, there was influenced to relationship between participation of Taekwondo and self-dentity. Second, there was influenced to relationship between participation of sport for all and academic achivement. Third, there was influenced to relationship between self-identity and academic achivement. Fourth, there was influenced to causual relationship among participation of sport for all, self-identity and academic achivement.

한국형 K-뉴스포츠 교육 프로그램 개발에 관한 연구

김동학(Kim, Dong-Hak) 한국웰니스학회 2023 한국웰니스학회지 Vol.18 No.2

건식저장용기에 대한 전복해석의 검증시험

김동학,서기석,이주찬,조천형,장현기,최병일,Kim Dong-Hak,Seo Ki-Seog,Lee Ju-Chan,Cho Chun-Hyung,Jang Hyun-Kee,Choi Byung-Il 한국방사성폐기물학회 2006 방사성폐기물학회지 Vol.4 No.3

A test of the 1/3 scale model was conducted to verify the tip-over analysis of a dry. concrete storage cask under a hypothetical accident condition. The tip-over analysis was executed using the velocity at each point as the initial conditions of the model just before the impact. The initial velocity was determined from the initial angular velocity, which would make the equivalent kinetic energy to the potential energy. To confirm the structural integrity of the canister, the visual testing and the non-detective testings such as Liquid Penetrant testing and Ultrasonic Testing were conducted. The lid of a storage cask was plastically deformed near the impact point. The structural integrity of storage cask was maintained. To verify the tip-over analysis the strains and the accelerations acquired by the tip-over test were compared with those by the analyses. The results of the analysis were larger than the test results about two times.

체육학분야 최우수 대학들의 교육과정 비교 연구

김동학(Kim Dong-Hak),김동환(Kim Dong-Whan),김승용(Kim Seung-Yong) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.1

This study is to offer a basic document and supper most suitable plan for course of physical education. To achieve the aim, the supper factor of a course of physical education which is selected best excellence among 'the evaluation authorization in knowledge' carried out the Korean Council for University Education. The subject of study is that five universities which are selected best excellence in field of physical education among superior eighteen universities, estimated to be best excellence in 'the evaluation authorization in knowledge' by the Korean Council for University Education. The method of study use case study for documents are made by self evaluation and collected record of best excellence universities, operate inductive category analysis. Also, the writer simultaneously use triangulation, peer debriefing and methodical reflection. As the conclusion, a course of physical education ought to organize a course of study suitably by character of each studies. This compose the subjects which are coincided with the educational purpose for advance in a course of physical education, is contents of subject step by step by a school year which are adequate to the detailed field of physical education. Moreover, people establish many subjects which give various chance to become a leader of variable society and nation and continuously develop them.

ScienceDMZ 기반 고성능 네트워킹 환경에서 분산 AI 추론 성능 비교 연구

김동학(Dong Hak Kim),문정훈(Jeong Hoon Moon) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.6

본 논문은 과학기술분야에서 관측, 실험장비의 비약적인 발전으로 과학빅데이터가 폭발적으로 증가하고 있으며 IT 를 비롯한 인공지능 기술의 발전으로 과학빅데이터의 분석 기법이 고도화 되고 있는 가운데 과학빅데이터에 대해 인공지능 기반의 GPU와 FPGA의 분석 및 추론 성능에 대한 비교 연구이다. 특히 과학빅데이터의 고속전송, 인공지능 기반의 분석, 공유 기술은 4 차산업시대의 핵심 기술이며, 이를 위한 다양한 IT 인프라와 기술체계가 구현되고 있는데, 본 논문에서는 이러한 여러 기술 체계 중빅데이터 고속도로 체계인 ScienceDMZ 기반의 고속전송 전용 노드인 DTN(Data Transfer Node) 상에서의 인공지능 학습과 추론 성능 비교연구로서 GPU 기반 DTN과 FPGA 기반 DTN 시스템의 성능을 비교 분석 하였다. 또한, 분석한 결과를 토대로 FPGA 가속기 카드가 적절히 활용될 수 있는 분야를 제시함과 동시에 ScienceDMZ 기반의 고성능 자원화 환경을 구축하는 방향성을 제시한다. 향후 ScienceDMZ 기반의 연구플랫폼 간 대규모 분산 환경에서의 인공지능 학습 및 추론을 위한 컴퓨팅 환경을 제안하였다.

중학생 뉴스포츠 참여자와 지도자간의 교환관계와 임파워먼트 및 학교생활만족 간의 구조적 관계

김동학(Kim, Dong-Hak),김동환(Kim, Dong-Whan),배정섭(Bae, Jung-Sup),장주선(Jang, Ju-Sun) 한국체육과학회 2018 한국체육과학회지 Vol.27 No.5

The purpose of study is to analyze the structural relationship among exchange relationship, empowerment and school life satisfaction of middle-school newsport participants and leader. In this study, 207 surveys were collected and the newsport participants were in S city middle-school. Data analysis was conducted using frequency analysis, reliability analysis, confirmatory factor analysis, correlation analysis, and structural equation model analysis. The analysis results are as follows. First LMX had a positive effect on empowerment. Second, TMX had a positive effect on empowerment. Third, LMX had a positive effect on school life satisfaction. Fourth, TMX had a positive effect on school life satisfaction. Fifth, empowerment had a positive effect on school life satisfaction. The results of this study suggest that it is possible to present basic data on the relationship between participants and leaders in the field of supplying new sports.

봉래꼬리풀의 종자 발아에 미치는 온도 조건과 화학적 처리의 영향

김동학,김영은,조승주,이종원,김상준,Dong-Hak Kim,Young-Eun Kim,Seungju Jo,Jong-Won Lee,Sang-Jun Kim 한국자원식물학회 2023 한국자원식물학회지 Vol.36 No.4

The germination characteristics of Pseudolysimachion kiusianum var. diamantiacum (Nakai) T.Yamaz., a rare and endemic plant designated by the Korea Forest Service, were investigated according to light conditions, temperature, and pretreatment. As a result of the germination experiment according to light conditions, it was determined that P. kiusianum is a photoblastic seed that does not germinate at all in dark conditions. The optimum germination temperature of the seeds was found to be 20-25℃, considering the final germination rate and germination time. Three growth regulators (IAA, GA₃, kinetin) and two inorganic salts (KNO₃, KCl) were pretreated to improve the germination rate of P. kiusianum seeds. The growth regulators IAA and kinetin had no significant effect on improving the germination rate of P. kiusianum seeds. On the other hand, GA₃ significantly increased the final germination percentage and germination rate regardless of the concentration, especially the treatment of more than 500 mg·L^-1 at 20℃ was more than 4 times more effective than the untreated. The inorganic salts KNO₃ and KCl had no significant effect on the seeds of P. kiusianum at low concentrations, but at higher concentrations (40 mM and 300 mM, respectively), they improved the germination rate and germination age by 2 times compared to the untreated. The results of this study will be useful for the mass propagation of P. kiusianum, which has the potential to be utilized as a native plant for restoration.

차광처리가 벌개미취와 구절초의 생장 및 생리적 특성에 미치는 영향

김동학,김영은,김상준,Kim, Dong-Hak,Kim, Young-Eun,Kim, Sang-Jun 한국환경복원기술학회 2022 한국환경복원기술학회지 Vol.25 No.4

본 연구에서는 차광처리가 벌개미취와 구절초의 생리적 반응에 미치는 영향을 조사하기 위해, 대조구(0%)와 3개의 서로 다른 차광처리구(50%, 75%, 95%)를 설치하고 엽록소 함량, 생장 및 광합성 특성을 조사하였다. 벌개미취와 구절초 모두 차광수준이 높아질수록 낮은 광도에 적응하기 위해 광합성에 대한 빛의 흡수 효율이 높은 잎이 형성되었다. 또한 차광수준이 높아질수록 낮은 광도에서 광합성을 수행하기 위해 암호흡속도의 저하와 광보상점의 감소가 나타났고, 광합성 효율을 높이기 위해 엽록소 함량과 순양자수율이 증가하였다. 광합성 속도는 대조구에서 가장 높았고 차광수준이 높아질수록 저하하였다. 대조구에서는 강광에 의한 수분손실을 막기 위해 기공전도도와 증산속도가 감소하였다. 50% 차광처리구의 기공전도도와 증산속도는 대조구에 비해 높았으나, 75%와 95% 차광처리구에서는 더 낮게 나타나 광합성 효율이 떨어지는 것으로 나타났다. 수분이용효율 또한 광합성속도와 유사한 경향으로 나타났고, 차광수준에 따라서 저하하는 것으로 나타났다. 벌개미취는 전천광보다 낮은 광 조건에서 생육할 시 광합성 능력이 저하하는 것으로 보이며, 구절초의 경우 50% 차광처리까지는 광합성에 큰 영향을 끼치지 않는 것으로 판단된다. 벌개미취와 구절초는 광을 제한하여 차광 상태를 지속하게 되면 생육에 불리할 것으로 판단된다. 이러한 벌개미취와 구절초의 생육특성은 상층임관이 존재하지 않은 DMZ 불모지와 같은 환경에 도입시키기 적합할 것으로 판단된다. This study was conducted to investigate the chlorophyll content, photosynthetic characteristics, and growth characteristics of Aster koraiensis and Dendranthema zawadskii var. latiloba according to shading treatment. A. koraiensis and D. zawadskii grew in four different shading treatment plots (0%, 50%, 75% and 95% of full sunlight) for experiments. It was found that as the shading level increased, the total chlorophyll content increased and dark respiration decreased in both A. koraiensis and D. zawadskii, indicating that A. koraiensis and D. zawadskii increase the utilization efficiency for photosynthesis under low light conditions. In addition, as the shading level increased, the net apparent quantum yield increased, resulting in the highest in the 95% shading plot, but the highest photosynthetic rate, water use efficiency, and leaf mass per area (LMA) were shown in the control group than in the shading treatments. The results showed that A. koraiensis and D. zawadskii are heliophytes showing plasticity to light, and if the light is restricted to continue to shade, it may be detrimental to growth. For healthy growth, it is considered suitable to grow A. koraiensis under full light conditions, and D. zawadskii under the light condition that blocks 0-50% of full sunlight.