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Design Optimization, Modeling, and Control of Unmanned Aerial Vehicle Lifted By Coandă Effect
Lee, Hyunyong,Han, Seonhye,Lee, Hyoju,Jeon, Jaehyeok,Lee, Choonghan,Kim, Yong Bum,Song, Seung Hwan,Choi, Hyouk Ryeol IEEE 2017 IEEE/ASME transactions on mechatronics Vol.22 No.3
<P>The Coanda effect is a natural phenomenon, which is that flowing fluid on a certain surface is pulled to the surface due to the viscosity of the fluid. This phenomenon can be utilized to produce the lift force of a flying object. This paper presents a new type of unmanned aerial vehicle (UAV) lifted by the Coanda effect, called SCoanda. We introduce the empirical study of its design and implementations. The principle of the Coanda effect is briefly explained in the first section. The design optimization and control of the UAV, and implementation issues are explained. The structural design of SCoanda is devised to use the maximum lift force produced by the Coanda effect. Since there are a plenty of cases about the shape of SCoanda, it has been limited to oval. It is investigated through computational fluid dynamics. As the result, an optimized design is determined among several candidates and appropriate structural materials are selected via tests. Also, dynamic modeling is suggested under several conditions of SCoanda before simulations are conducted to build up a controller and determine gains according to the dynamic modeling. Finally, the UAV is manufactured and its performances are successfully demonstrated in the indoor and the outdoor environments.</P>
Temperature-dependent Differences in Heading Response at Different Growth Stages of Rice
Lee, HyeonSeok,Choi, MyoungGoo,Lee, YunHo,Hwang, WoonHa,Jeong, JaeHyeok,Yang, SeoYeong,Lim, YeonHwa,Lee, ChungGen,Choi, KyungJin The Korean Society of Crop Science 2019 한국작물학회지 Vol.64 No.3
There is an increasing frequency in the occurrence of abnormal weather phenomena such as sharp increases and decreases in temperature. Under these weather conditions, the heading time of rice changes unexpectedly, which poses problems in agriculture. Therefore, we investigated the effect of temperature on the heading response at different growth stages in rice. During the period from transplanting to heading, the plants were subjected to different temperature treatments, each for a 9-day period, to observe the heading response. For the heading date analysis, "heading date" was defined as the number of days from transplanting to the appearance of the first spikelet. We found that the influence of temperature increased in the order of rooting stage, followed by meiosis, early tillering, spikelet differentiation, and panicle initiation stage in all ecological types and cultivars. In particular, unlike the results reported previously, the effect of temperature on heading during the photo-sensitive period was very small. Meanwhile, the influence of temperature on vegetative growth response at different growth stages was not consistent with heading response. These results can be used as basic data for predicting the variation in heading date owing to temperature variation at each growth stage. In addition, we propose that the concept of day length should be included in determining the influence of temperature on the photo-sensitive period.
QGIS와 Scapetoad 프로그램으로 만든 주기율표 카토그램을 활용한 고등학교 화학 교과서에서 다루는 원소의 출현 빈도 분석
이재혁(Lee, Jaehyeok),김영훈(Kim, Young Hoon),백성혜(Paik, Seounghey) 한국교원대학교 융합교육연구소 2022 융합교육연구 Vol.8 No.1
이 연구에서는 2015 개정 교육과정의 통합과학 교과서 5종의 화학 관련 대단원 3개, 화학Ⅰ 교과서 9종과 화학Ⅱ 교과서 6종에 제시된 물질들을 구성하는 원소의 출현 빈도를 주기율표를 활용한 카토그램으로 분석하였는데, 이는 영역의 정확한 지리적인 위치와 경계보다는 경계 내에 있는 특정한 주제에 대한 수치를 강조하는 지도로 표현하는 것이다. 분석 결과, 고등학교 통합과학의 화학 영역, 화학Ⅰ, 화학Ⅱ 교과서와 관계없이 산소, 수소, 탄소 및 일부 원소의 출현 빈도가 다른 원소들에 비해 매우 심각하게 높은 것으로 나타났다. 3종류의 교과서에 있는 원소들을 11개 대단원별로 나누어 분석한 결과, 8개 대단원에서 다루는 원소의 출현 편중의 경향이 유사하게 나타내었다. 3개의 대단원에서만 독특한 카토그램의 형태를 보였는데, 화학Ⅰ 교과목에서 1개, 화학Ⅱ 교과목에서 2개였다. 화학 개념을 다루는 소재를 몇 개의 원소들만으로 제한하게 되면, 학생들이 원소의 주기성이나 다양한 원소의 성질을 이해할 기회를 얻기 어려울 것이다. 따라서 화학 교과서 저자들은, 더욱 다양한 원소를 활용한 사례를 화학 교과서에서 다룸으로써, 화학을 배우는 학생들이 다양한 원소에 대한 지식을 풍부하게 얻을 기회를 제공할 필요가 있다. This study analyzed the emergence frequency of the elements that make up materials presented in the textbooks of 3 chemistry chapters in 5 ‘Integrated Science’ textbooks, 9 ‘Chemistry Ⅰ’ textbooks, and 6 ‘Chemistry Ⅱ’ textbooks in the 2015 revised curriculum using periodic table cartogram, which describes as map that accents numerical value of certain theme inside of the boundaries besides exact geographical locations and boundaries. As a result of the analysis, the emergence frequency of oxygen, hydrogen, carbon, and some elements was very seriously high compared to other elements regardless of the textbooks of chemistry section of high school Integrated Science, Chemistry Ⅰ, and Chemistry Ⅱ. As a result of dividing and analyzing the elements in 3 types of textbooks into 11 chapters, the tendency of the bias of the emergence of the elements covered by 8 chapters is similar. The study found that the frequency of the element s appearance was biased to oxygen, hydrogen, carbon, and some elements, regardless of each subject. And eight out of 11 chapters of these textbooks were also showing the same tendency. Only three chapters showed unique appearance of cartogram; one in the Chemistry Ⅰ course and two in the Chemistry Ⅱ course. If the material dealing with the concept of chemistry is limited to only a few elements, students will not have the opportunity to understand the periodicity of the elements or the properties of various elements. Therefore, it is necessary for authors of chemistry textbooks to provide an opportunity for students who learn chemistry to have a wealth of knowledge about various elements by dealing with cases using more various elements in chemistry textbooks.
디지털 사회 혁신에서 리빙랩 프로젝트의 성과지표에 대한 연구
이재혁(Jaehyeok Lee),이정훈(Junghoon Lee),조경환(Kyounghwoan Cho) 한국IT서비스학회 2019 한국IT서비스학회지 Vol.18 No.5
In recent years, Digital Social Innovation has been emerging at home and abroad and new solutions are being proposed by the perspective of User using digital technology in order to solve social and economic problems of the city. In addition, Living Labs which is an innovative tools and space enable to solve problems doing activities with various participants led by users. Therefore, this study aims to systematically manage the activities of Living Lab in Digital Social Innovation and improves the Living Lab sustainability using the performance indicators which are going to be developed. Furthermore, construct the appropriate indicator of each project process and take test at real Living Labs. As a result, performance indicator was derived from each procedure in the Living Lab project, and proved validity and reliability of the indicators through qualitative and quantitative methods by interviews and the questionnaire from the participants of Living Labs.
과학의 본성의 교육적 응용을 위한 화학교사 교육프로그램의 효과
이재혁(Jaehyeok Lee),백성혜(Seoung-Hey Paik) 한국교원대학교 융합교육연구소 2022 융합교육연구 Vol.8 No.2
이 연구의 목적은 화학 교사의 RFN에 대한 인식과 교육적 적용을 향상시키기 위해 RFN을 상황에 맞게 명시적으로 가르치는 교육프로그램을 개발하고, 이를 통한 화학 교사의 RFN교육적 응용에 대한 인식과 그 변화를 분석하여 프로그램의 교육적 효과를 확인하는 것이다. 이를 위해 RFN의 교육적 응용이 실제로 적용될 수 있도록 Shapin & Schaffer(1985)의 “Leviathan and Air-Pump”를 이용해 RFN을 명시적으로 반영한 과학사 읽기 자료와 실험자료를 개발하고, 이를 활용한 교육프로그램을 개발하였다. 연구 대상자는 충북 사범대학 석사과정에 재학 중인 현직 화학 교사 3명과 예비 화학 교사 2명이고, 15주 과정의 교육프로그램에 투입하였다. 먼저 RFN의 교육적 응용에 대한 예비 설문을 통해 연구 대상자의 RFN 교육적 응용에 대한 사전 인식을 확인하고, 개발된 읽기 자료와 실험 자료를 제공하여 토론한 후 RFN을 반영한 교육자료를 개발하는 과정을 거쳤다. 이후 RFN의 교육적 응용에 대한 사후 인식을 확인하고, 개발된 교재에 대한 사전 학습 및 인식과 비교하였다. 연구 결과 연구 대상자는 '사회-제도적 측면' 범주에서 금융 시스템 및 전문적 활동에 대한 인식, '과학적 지식' 범주에서 분야별 과학 지식, '과학적 방법' 범주에서 탐구과정의 다양성에 대한 인식이 제고되었음을 확인하였다. The purpose of this study is to develop an educational program to teach RFN contextually and explicitly in order to improve the chemistry teachers' awareness and the educational application of RFN, and to examine the educational effects of chemistry teachers by checking chemistry teachers’ perceptions and changes on perceptions of educational applications of RFN the of chemistry teachers for through the program. The educational program was developed based on contextual scientific history reading materials and experimental materials that explicitly reflected RFN were developed so that the educational application of RFN could be actually applied, using Shapin & Schaffer(1985)'s “Leviathan and the Air-Pump”. The developed educational program selected three in-service chemistry teachers and two pre-service chemistry teachers who are enrolled in the master's course of the College of Education in Chung-buk as research subjects, and were put into the 15-week course program. Through a preliminary questionnaire on the educational application of RFN, the research subjects' prior awareness of the RFN educational application was confirmed, and the developed reading materials and experimental materials were provided for discussion. After developing educational materials reflecting RFN, the post-recognition of RFN educational application was confirmed and compared with the pre-study and the perception in the developed teaching materials. As a result of the study, the research subjects improved their awareness about the financial system and professional activities in the 'socio-institutional aspect' category, scientific knowledge by discipline in the 'scientific knowledge' category, and the diversity of the inquiry process in the 'scientific method' category.