대학의 자치와 자율적 평가

김옥환,Kim, Ok-Hwan 한국대학교육협의회 1984 大學敎育 Vol.7 No.-

무선통신을 위한 이중대역 마이크로스트립 안테나 설계

김옥환,Kim, Oug-Whoan 한국전자통신학회 2012 한국전자통신학회 논문지 Vol.7 No.6

본 논문에서는, 무선통신을 위한 이중대역 마이크로스트립 안테나를 설계하였다. IEEE 802.11a의 대역인 Hyper LAN(5.725~5.825GHz)에서도 사용 할 수 있도록 설계하였다. 제안된 안테나의 기판은 FR-4이고 크기는 $22mm{\times}23mm$, 두께는 1.6mm로 구성하였으며, 시뮬레이션은 CST Microwave Studio 2010을 사용하였다. 설계된 안테나의 시뮬레이션 결과 5GHz와 5.8GHz의 대역에서 공진을 나타내고 -10dB 이하에서 양호한 반사손실을 보였다. In this paper, we design of dual-band microstrip antenna for wireless communication. We used IEEE 802.11a and Hyper LAN (5.725~5.825 GHz). The proposed antenna substrate is FR-4, size is $22mm{\times}23mm$, thickness is 1.6mm and used to CST Microwave Studio 2010 program. As a result the simulation has good result and good return loss below -10 dB at 5 GHz and 5.8 bandwidth.

한국 대학의 몇 가지 문제와 전망

김옥환,Kim, Ok-Hwan 한국대학교육협의회 1985 大學敎育 Vol.15 No.-

대학의 자율성과 한계

김옥환,Kim, Ok-Hwan 한국대학교육협의회 1990 大學敎育 Vol.45 No.-

폴리우레탄 폼의 Isocyanate/Polyol 혼합비율 변화에 따른 정적 안락감 특성

김성육(Sungyuk Kim),김현지(Hyunji Kim),지효성(Hyoseong Ji),김기선(Keysun Kim),김옥환(Okwhan Kim),전용두(Yongdu Jun) 한국자동차공학회 2019 한국자동차공학회 학술대회 및 전시회 Vol.2019 No.11

식물 잎의 수분함량을 포함한 스트레스 측정 방법

김영춘(Young-Choon Kim),조문택(Moon-Taek Cho),주해종(Hae-Jong Joo),김갑수(Kab-Soo Kim),김옥환(Ok-Hwan Kim),김현종(Hyun-Jong Kim) 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.- No.-

식물의 성장에 있어서 여러 종류의 빛 파장을 이용하여 식물 잎의 각 기관에서의 이상징후에 의한 파장의 반사/흡수 및 형광발관 등에 관한 연구가 이루어지고 있다. 본 논문에서는 가시광선 영역과 NIR 영역에 있어서 식물잎의 반사 잎을 이용하여 식물 잎의 수분함량을 포함한 스트레스 측정방법을 제안했다.

토요스포츠데이 참여에 따른 청소년의 스포츠자신감 및 운동몰입의 차이

김옥환(Kim, Ok-Hwan) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.1

It’s been five years since Saturday sport programs were introduced, but few studies have yet examined these programs, though a lot of research efforts have been directed into youth sport activities. The purpose of this study was to examine the impact of the participation of adolescents in Saturday sport programs on their sport confidence and exercise flow in an effort to provide some information on policy setting about the programs. The instrument used in this study was questionnaire that consisted of 26 items, which were three items on demographic characteristics, 12 on sport confidence and 11 on exercise flow. After a self-administered survey was conducted, the answer sheets were gathered, and a statistical package SPSS 18.0 was employed to carry out frequency analysis, exploratory factor analysis, t-test, one-way ANOVA and post-hoc analysis. The findings of the study were as follows: First, as for differences in sport confidence according to demographic characteristics including gender, the boy group was ahead of the girl group in trait sport confidence(t=1.99, p<.05), but there were no significant differences between the boys and the girls in state sport confidence. But significant gender differences were found according to grader. In addition, there were no statistically significant differences in state sport according to grade. on the other hand, significant differences were found in trait sport confidence according to grade(F=3.28, p<.05). Second, regarding differences in exercise flow according to gender, there were lots of gender differences in cognitive flow(t=-4.57, p<.001) and behavioral flow(t=-0.96, p<.001). No significant differences were found in cognitive flow according to grade, and there were significant differences in behavioral flow(F=5.87, p<.01) according to that. Significant differences were found in cognitive flow according to the sporting events, but there were no significant differences in behavioral flow.

방과후 체육활동 참여가 청소년의 공격성 및 자아탄력성에 미치는 영향

김옥환(Ok-Hwan Kim),이상진(Sang-Jin Lee) 한국발육발달학회 2017 한국발육발달학회지 Vol.25 No.1

Adolescence is a period that is characterized by rapid physical growth, strong instinctive needs for activity and physical development that is required for successful life. Indeed, the importance of this period cannot be overestimated. In fact, however, the rate of students who engaged in strenuous physical activities for three days or more a week, which is one of physical activity indicators, just stood at 57.0 percent in elementary schools; 36.5 percent in middle schools; and 25.6 percent in high schools, when the health screening data of 764 selected schools from all parts of the country were analyzed to find out about the physical development of elementary and secondary students, their healthy activities and major diseases(the Ministry of Education, 2016). The rate decreased with school year. The purpose of this study was, therefore, to examine the impact of the participation of adolescents in after-school P.E. activities on their aggressiveness and ego-resilience. The subjects in this study were 155 students who were selected from a high school located in the city of Euiwang, Gyeonggi Province. The students participated in after-school P.E. activities in the first semester of 2016. A self-administered survey was conducted with their consent, and their answer sheets were gathered. The collected data were analyzed by a Korean version of SPSS 20.0, and t-test was carried out to look for any possible differences between pretest and posttest average scores. The findings of the study were as follows: First, whether the students underwent any changes in aggressiveness after their participation in the after-school P.E. activities was analyzed. As a result, there were statistically significant differences in every area that was physical aggressiveness, verbal aggressiveness, hostility and anger. Second, whether the students underwent any changes in ego-resilience after their participation in the after-school P.E. activities was analyzed. As a result, there were statistically significant differences in every area that was interpersonal relationships, emotional regulation, positive attitude and confidence.

중학생의 학교스포츠클럽 참여가 학교생활적응 및 운동지속 의도에 미치는 영향

김옥환(Oh-Hwan Kim),이상진(Sang-Jin Lee) 한국발육발달학회 2019 한국발육발달학회지 Vol.27 No.4

In this study, middle school students based in Suwon City were selected as a population, using the method of extraction of convenience among non-probability labels. The conclusion obtained by asking 150 students who participated in the activities of the school sports club from April to July to agree to participate in the research is as follows. First, after looking into the effect of participating in school sports clubs on the adaptation of school life, there was a significant difference in p<0.05 in school life, and there was no significant difference between school study and school teacher. Second, after looking into the effect of participating in school sports clubs on the intention of sports, there were significant differences in p<0.05 in all trends, intensities and possibilities.

조선강재의 최적 용접조건에 관한 연구

김옥환(Ok-Hwan Kim) 한국기계가공학회 2011 한국기계가공학회지 Vol.10 No.6

In this study, the steel material for shipbuilding(LR-A class) was used, and FCAW was taken advantage of 3G attitude and they are welded by different welding ways. As a result of analyzing wave with welding monitoring system, the stable values are obtained which are the first floor(electronic current 164~182 A, voltage 24 V), the second floor(electronic current 174~190 A, voltage 22~25 V), the third floor(electronic current 158~188 A, voltage 22~25 V), and fourth floor(electronic current 172~184 A, voltage 22~25 V), at this time, the stable wave standard deviation and changing coefficient could be obtained. When the welding testing through nondestructive inspection was analyzed know defect of welding, there was no defect of welding in A, D, E, but some porosities in B, and slag conclusion near the surface in C, because the length of arc was not accurate, and the electronic current and voltage was not stable. After observing the change of heat affect zone through micro testing, each organization of floor formed as Grain Refinement, so welding part was fine, the distance of heat affect zone is getting wider up to change the values of the electronic current and voltage. As a result of degree of hardness testing, the hardness orders were the heat affect zone(HAZ), Welding Zone(WZ), and Base Metal(BM). When the distribution of degree of hardness is observed. B is the highest degree of hardness The reason why heat effect zone is higher than welding zone and base metal, welding zone is boiled over melting point(1539℃) and it starts to melt after the result of analysis through metal microscope, so we can know that delicate tissue is created at the welding zone. Therefore, in order to get the optimal conditions of the welding, the proper current of the welding and voltage is needed. Furthermore the precise work of welding is required.