알루미늄 박판형 다채널 써모사이폰의 열성능에 관한 실험적 연구

권용하,김종수 한국수산해양교육학회 2020 水産海洋敎育硏究 Vol.32 No.1

Conventional researches on thermosyphons have been difficult to use in industrial fields because most of them are lab level studies under limited conditions and poor economics and practicality. This study have been conducted to evaluate the thermal performance and characteristics of aluminium thin plate multi channel thermosyphon which is widely used in real products for their excellent thermal performance and stability. This thermosyphon was tested at various charging ratios, heat transfer rates, and inclination angles to provied easy to use thermal performance data. We proposed a correlation within 14% of mean error using graphical analysis for dimensionless numbers(Bo and Ku) according to heat transfer rate.

알루미늄 박판형 Closed End Pulsating Heat Pipe의 열성능에 관한 실험적 연구

권용하,김종수 한국수산해양교육학회 2020 水産海洋敎育硏究 Vol.32 No.1

We fabricated experimental closed end type PHP that improved productivity and economy using aluminium thin plate multi channel thermosyphon with excellent thermal performance and responsiveness to heat loads. This study have been conducted to evaluate the thermal performance and characteristics of the closed end PHP using HFE-7100 under various filling ratios, heat transfer rates and inclination angles, and to suggest thermal performance data easy to use. We proposed a correlation within 10% of mean error using graphical analysis for dimensionless number(Bo and Ku) according to heat transfer rate.

The Role of Noise in a Mutual Selection and Learning Model

권용하,안정수,양재석,김지현 연세대학교 동서문제연구원 2016 동서연구 Vol.28 No.2

In organizational learning and search literature, conventional wisdom holds that a moderate degree of noise helps organizations improve their performance by introducing more variation. We would like to note, however, that portrayals of most organizational structures in this line of inquiry are over simplified. We contribute to this topic by suggesting that the beneficial role of moderate noise is dependent on its relational presence in a mutual selection and learning system. By extending March’s (1991) mutual learning model, we examine the role of noise in an organization as an adaptive system, where both the organizational code and individuals can select and learn from others. We demonstrate that while a small amount of noise on the learning stage is beneficial, noise on the selection stage monotonically decreases performance. Our results indicate a need for re-examination of the role of noise in various organizational settings and structures.

음악이 초등학생의 운동수행능력과 신체활동 즐거움에 미치는 효과

권용하,박정화 한국초등체육학회 2017 한국초등체육학회지 Vol.23 No.1

본 연구는 음악이 초등학생의 운동수행능력과 신체활동 즐거움에 미치는 영향을 규명하는데 목적이 있다. 연구대상은 ㄱ도 ㄱ시에 소재한 ㅇ초등학교 4, 5, 6학년 학생 481명으로, 각 학년 K-POP집단, 동요 집단, 무음악 집단으로 나누었다. 운동수행능력은 근력(악력), 유연성(앉아 윗몸 앞으로 굽히기), 순발력(제자리 멀리뛰기), 심폐지구력(왕복 오래 달리기)으로 하였으며, 신체활동 즐거움은 박순이(2000)의 신체활동 즐거움 검사지를 이용하였고, 처치 전 측정은 모든 집단에 무음악으로 하였으며, 처치 후는 각 집단별로 K-POP, 동요를 들려주며 측정을 하였다. 본 연구의 자료 처리 방법은 집단 간 비교를 위하여 공변량 분석을 사용하였으며, 사후검점은 Tukey HSD법을 이용하였다. 검사지의 타당성 확보를 위해 탐색적 요인분석을 실시하였고, 신뢰성을 위해 Cronbach's α 계수를 이용하였다. 모든 통계적 유의수준은 5%로 하였다. 이와 같은 연구방법과 절차를 통하여 다음과 같은 결과를 얻었다. 첫째. 운동수행능력에서 근력은 여자 4학년 동요집단이 보다 높고, 유연성은 K-POP집단, 동요집단, 무음악집단 순으로 높다. 순발력은 성과 집단에 상관없이 5, 6학년이 4학년보다 높다. 심폐지구력은 K-POP집단, 무음악집단, 동요집단 순으로 높고, 남자의 경우 4학년이 가장 높으며, 여자의 경우 K-POP집단이 가장 높다. 둘째, 신체활동 즐거움은 재미요인과 협동요인에서는 K-POP집단과 동요집단이 무음악 집단보다 높으며, 창의요인는 K-POP집단이 무음악 집단보다 높고 남자 5학년 K-POP집단이 높다. 건강요인에서는 K-POP집단이 동요집단과 무음악 집단보다 높다. 이러한 결과를 종합했을 때 초등학교 4, 5, 6학년 학생들에게 운동수행능력 및 신체활동 즐거움을 향상시키기 위하여 운동수행능력 종목과 즐거움 요인의 결과에 따라 K-POP과 동요를 적절히 활용하는 것이 좋다. The purpose of this study is to examine effects of music on elementary school students' exercise performance ability and physical activity enjoyment. Subjects of the study are 481 fourth, fifth, and sixth-year students of O Elementary School located in G City, G Province and each grader was divided into a K-POP group, a children's song group, and an a-music group. The exercise performance ability was muscular strength, flexibility, power, and cardiovascular endurance. The physical activity enjoyment was investigated by using a questionnaire of 'the physical activity enjoyment' by Park, Suni(2000). For the study's data processing method, the ANCOVA was used to compare the groups with one another. And for the post-hoc, the Tukey HSD method was used. The exploratory factor analysis was carried out to secure the questionnaire's validity. The Cronbach's α coefficient was used for its reliability. All the statistical significance levels were set as 5%. The following conclusion was drawn through these research method and procedure. First, in the exercise performance ability, the children's song group of female fourth-year students of muscular strength is higher and the flexibility is higher in order of the K-Pop group, the children's song group, and the a-music group. The fifth and sixth-year students' quickness is higher than the fourth-year students. Cardiovascular endurance is higher in order of the K-Pop group, the a-music group, and the children's song group. And for the male students, the fourth-year students are highest. And for the female students, the K-Pop group is highest. Second, for the physical activity enjoyment, the K-Pop group and children's song group's fun and cooperation factors are higher than those of the a-music group. The K-Pop group's creativity factor is higher than that of the a-music group. And the male fifth-year students' K-Pop group is higher. The K-Pop group's health factor is higher than that of the children's song group and a-music group. When the above results were combined, proper utilization of K-Pop and children's songs is good according to the exercise performance ability and results of the enjoyment factor to improve fourth, fifth, and sixth-year students' exercise performance ability and physical activity enjoyment.

Oblong 셀 앤 플레이트 열교환기에서의 단상 열전달, 압력강하 특성 및 성능예측 프로그램 개발에 관한 연구

권용하,김영수,박재홍 한국마린엔지니어링학회 2004 한국마린엔지니어링학회지 Vol.28 No.6

In this study, single-phase heat transfer experiments were conducted with Oblong Shell and Plate heat exchanger using water. An experimental water loop has been developed to measure the single-phase heat transfer coefficient and pressure drop in a vertical Oblong Shell and Plate heat exchanger. Downflow of hot water in one channel receives heat from the cold water upflow of water in the other channel. Similar to the case of a plate heat exchanger, even at a very low Reynolds number, the flow in the Oblong Shell and Plate heat exchanger remains turbulent. The present data show that the heat transfer coefficient and pressure drop increase with the Reynolds number. Based on the present data, empirical correlations of the heat transfer coefficient and pressure drop in terms of Nusselt number and friction factor were proposed. Also, performance prediction analyses for Oblong Shell and Plate heat exchanger were executed and compared with experiments. $\varepsilon$-NTU method was used in this prediction program. Independent variables are flow rates and inlet temperatures. Compared with experimental data, the accuracy of the program is within the error bounds of $\pm$5% in the heat transfer rate.

진공로(眞空爐) 브레이징 용재의 용융점 도달 시간에 관한 수치해석적 연구

권용하(Yong-Ha Kwon),전종훈(Jong-Hoon Jeon),김인관(In-Koan Kim),김영수(Young-Soo Kim) (사)한국CDE학회 2006 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2006 No.2

알루미늄 박판형 다채널 써모사이폰과 Pulsating Heat Pipe의 열성능 비교 연구

권용하(Yong-Ha Kwon),김종수(Jong-Soo Kim),김정훈(Jeong-Hun Kim) 한국동력기계공학회 2020 동력시스템공학회지 Vol.24 No.2

이중 이동 라우터를 이용한 끊김없는 네트워크 이동성 지원 방안

권용하(Yong-ha Kwon),박희동(Hee-Dong Park),이강원(Kang-Won Lee),조봉관(Bong-Kwan Cho),조유제(You-Ze Cho) 한국통신학회 2005 한국통신학회 학술대회 및 강연회 Vol.2005 No.4

정밀도로지도 제작을 위한 Web GIS 기반 HD Map 프로토타입 구축 연구

권용하 ( Yong-ha Kwon ),정윤재 ( Yun-jae Choung ),조현지 ( Hyun-ji Cho ),구본엽 ( Bon-yup Gu ) 한국지리정보학회 2021 한국지리정보학회지 Vol.24 No.2

4차 산업혁명의 대표라고 할 수 있는 자율주행차량의 안전한 운행을 위해서는 센서 기술, 소프트웨어 기술, 차량 기술 등 다양한 기술 조합이 필요하다. 자율주행차량은 차량 내에 탑재된 다양한 센서를 통해서 현재의 위치정보와 주변 상황을 인지하여 운전자에게 의존하지 않고 스스로 판단하고 주행하는 차량이다. 완전자율주행을 위해서는 완벽한 인지기술이 필요하고 정밀도로지도는 차선, 정지선, 신호등, 횡단보도 등에 대한 정보를 정밀하게 제공하고 있기 때문에 자율주행 차량에서 발생하는 인지 오차를 최소화시킬 수 있음으로, 신뢰성 있는 자율주행차량을 위해서는 도로위 다양한 시설물들의 위치정보를 차량에 입력한 정밀지도 정보가 필수적이다. 본 연구에서는 정밀도로지도의 정의 및 필요성 국내외 동향을 분석하고 실제 운영되고 있는 대구광역시 자율주행 특화지역(수성의료지구, 약 24㎞)과 세종특별자치시 행복도시(약 33㎞), 서울대학교 시흥캠퍼스 FMTC(Future Mobility Technical Center) PG(Proving Ground)를 대상으로 국토지리정보원 MMS(Mobile Mapping System) 측량 성과물을 활용하여 정밀도로지도 서비스인 Web GIS 기반 HD(High Definition) Map 프로토타입을 구축하였다. 추후 연구에서는 본 연구에서 구축한 정밀도로지도 서비스를 자율주행차량 및 관제 시스템에 탑재 시켜 실시간 위치검증 및 위치보정 알고리즘의 성능 검증을 진행하고자 한다. For the safe operation of autonomous vehicles, the representative technology of the 4^th industrial revolution era, a combination of various technologies such as sensor technology, software technology and car technology is required. An autonomous vehicle is a vehicle that recognizes current location and situation by using the various sensors, and makes its own decisions without depending on the driver. Perfect recognition technology is required for fully autonomous driving. Since the precise road maps provide various road information including lanes, stop lines, traffic lights and crosswalks, it is possible to minimize the cognitive errors that occur in autonomous vehicles by using the precise road maps with location information of the road facilities. In this study, the definition, necessity and technical trends of the precise road map have been analyzed, and the HD(High Definition) map prototype based on the web GIS has been built in the autonomous driving-specialized areas of Daegu Metropolitan City(Suseong Medical District, about 24㎞), the Happy City of Sejong Special Self-Governing City(about 33㎞), and the FMTC(Future Mobility Technical Center) PG(Proving Ground) of Seoul National University Siheung Campus using the MMS(Mobile Mapping System) surveying results given by the National Geographic Information Institute. In future research, the built-in precise road map service will be installed in the autonomous vehicles and control systems to verify the real-time locations and its location correction algorithm.

상호선택 및 학습모델에서 노이즈의 역할

권용하(Yongha Kwon),안정수(Jungsoo Ahn),양재석(Jae-Suk Yang),김지현(Ji-hyun Kim) 연세대학교 동서문제연구원 2016 동서연구 Vol.28 No.2

조직학습과 탐색 연구에서 적당한 수준의 노이즈는 조직에게 변화를 제공함으로서 성과에 긍정적인 영향을 미칠 수 있음이 밝혀졌다. 우리는 기존의 관련 연구에서 조직 구조에 대한 검토가 지나치게 간소화되어 왔음에 주목하여, 본 연구에서 적당한 수준의 노이즈가 상호 선택 및 학습 모델의 위치에 따라 그 역할이 달라질수 있음을 제시한다. 우리는 James G. March (1991)의 학습 모델을 확장하여, 조직의 코드와 개인이 상호 선택, 학습하는 모델에서 노이즈의 역할을 탐구한다. 본 연구를 통해 학습 단계에서의 노이즈는 성과에 긍정적이나, 선택 단계에서의 노이즈는 부정적임을 밝혀냈으며, 이 결과는 노이즈의 역할이 다양한 조직 구조 에서 재검토될 필요가 있음을 보여준다. In organizational learning and search literature, conventional wisdom holds that a moderate degree of noise helps organizations improve their performance by introducing more variation. We would like to note, however, that portrayals of most organizational structures in this line of inquiry are over simplified. We contribute to this topic by suggesting that the beneficial role of moderate noise is dependent on its relational presence in a mutual selection and learning system. By extending March’s (1991) mutual learning model, we examine the role of noise in an organization as an adaptive system, where both the organizational code and individuals can select and learn from others. We demonstrate that while a small amount of noise on the learning stage is beneficial, noise on the selection stage monotonically decreases performance. Our results indicate a need for re-examination of the role of noise in various organizational settings and structures.