• International Journal of Aeronautical and Space Sciences
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• 제14권4호
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• pp.297-309
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• 2013

Design optimization is a mathematical process to find an optimal solution through the use of formal optimization algorithms. Design plays a vital role in the engineering field; therefore, using design tools in education and research is becoming more and more important. Recently, numerical design optimization in fluid mechanics, which uses computational fluid dynamics (CFD), has numerous applications in the engineering field, because of the rapid development of high-performance computing resources. However, it is difficult to find design optimization software and contents for educational purposes in aerospace engineering. In the present study, we have developed an aerodynamic design framework specifically for an airfoil, based on the EDucation-research Integration through Simulation On the Net (EDISON) portal. The airfoil design framework is composed of three subparts: a geometry kernel, CFD flow analysis, and an optimization algorithm. Through a seamless interface among the subparts, an iterative design process is conducted. In addition, the CFD flow analysis and the design framework are provided through a web-based portal system, while the computation is taken care of by a supercomputing facility. In addition to the software development, educational contents are developed for lectures associated with design optimization in aerospace and mechanical engineering education programs. The software and content developed in this study is expected to be used as a tool for e-learning material, for education and research in universities.

• 한국환경과학회지
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• 제27권7호
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• pp.519-529
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• 2018

With rapid economic growth, the urban environment has created a problem of human physical and mental illness. In order to solve these problems, urban forests have emerged as a way to mitigate the environmental risks through improving the polluted environment of the city and improve the quality of life. As the urban forests have expanded, the school forests movement has also been taking an important place recently. The study focused on the performance of school forests by comparing the perceptions among teachers and students about their functions. The questionnaire was composed of 4 questions concerning human matters, 10 questions for space recognition, 4 questions for thermal environment, 2 questions for health promotion, and 20 total questions for composition of survey items. The reliability of the school forest function, number of tree planting areas and quantities, the harmony of the planting, and the satisfaction of the school forest were analyzed in the questionnaire conducted by the school members. Although it does not recognize school forests, it has a positive response to the green space that is built outdoors. It is considered that outdoor education and environmental education are sufficient in school forests and green spaces. The results showed that the outdoor green space was more satisfactory when compared with the general school. Teachers and students' preferences were similar to 'seasonal changes' and' trees of various colors and shapes'. The reliability analysis between each item shows that the coefficient for cronbach's ${\alpha}$ was .700 to .834. The purpose of this study is to identify the perception of forest function among school forest members and to utilize them as a basic data in the future.

• Journal of applied mathematics & informatics
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• 제12권1_2호
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• pp.409-417
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• 2003

There are two rotation matrix parameters in a model, pro-posed by Prentice in 1989, for pairs of rotations in 3 dimensional space. For the least squares estimates of the two parameters, an algorithm was also presented, but it turned out that the algorithm could fail to get the least squares estimates. This article provides another algorithm for the least squares estimates and its performance is demonstrated by simulation results.

• 한국전자거래학회지
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• 제12권4호
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• pp.185-209
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• 2007

최근의 정보기술 개발은 온라인 훈련에 기여하였으며 이러닝 혹은 가상 교육 등과 같이 유사한 개념으로 사용되고 있는 기업에서의 온라인 교육은 피교육자에게 다양한 방법으로 교육 기회를 제공하고 있다. 또한 전자적인 측면에서 일괄 서비스 체계의 솔류션을 제공하는 혁신 서비스로서의 기능을 제공하고 있으며 온라인 교육 환경하에서는 교육자와 피교육자가 시간과 장소에 구애받지 않고 개인화된 교육 패키지를 공급할 수 있게 한다. 본 논문에서는 온라인 교육에 영향을 미치는 요인들을 독립 변수로 하고 교육 성과와 전달 성과의 두 가지 측면에서의 교육 효과성을 종속 변수로 하는 관계를 실증적으로 검증하였다. 기존의 연구 결과를 기반으로 8개의 가정을 설정하고 설문서를 작성하여 LISREL을 이용하여 분석 한 결과 피교육자에 기인된 개별적 변수와 조직 변수가 훈련 효과성과 유의성이 있는 것으로 나타났다

• Journal of Computing Science and Engineering
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• 제10권4호
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• pp.103-110
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• 2016

Emotion recognition is an important component of affective computing, and is significant in the implementation of natural and friendly human-computer interaction. An effective approach to recognizing emotion from text is based on a machine learning technique, which deals with emotion recognition as a classification problem. However, in emotion recognition, the texts involved are usually very short, leaving a very large, sparse feature space, which decreases the performance of emotion classification. This paper proposes to resolve the problem of feature sparseness, and largely improve the emotion recognition performance from short texts by doing the following: representing short texts with word cluster features, offering a novel word clustering algorithm, and using a new feature weighting scheme. Emotion classification experiments were performed with different features and weighting schemes on a publicly available dataset. The experimental results suggest that the word cluster features and the proposed weighting scheme can partly resolve problems with feature sparseness and emotion recognition performance.

• 한국전자통신학회논문지
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• 제15권2호
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• pp.219-224
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• 2020

본 논문에서는 협소 공간에서 다중 빔 패턴 생성 및 제어를 위한 고집적 안테나에 대하여 고찰하였다. SPA (: Switched Parasitic Antenna) 안테나 구조의 기본적인 Dipole SPA와 Monopole SPA 구조의 특징과 성능을 도시하였고, Monopole SPA 안테나를 직접 제작하여 챔버 내에서 802.11g를 시스템에 적용하여 그 성능을 실측하였다. 상용 안테나 대비 제작한 SPA 안테나를 사용하여 평균 전송 속도를 측정하였을 때 최대 8.7배 우수한 성능이 나타남을 확인하였다.

• 천문학회지
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• 제55권1호
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• pp.11-22
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• 2022

We introduce the Transformable Reflective Telescope (TRT) kit that applies an aluminum profile as a base plate for precise, stable, and lightweight optical system. It has been utilized for optical surface measurements, developing alignment and baffle systems, observing celestial objects, and various educational purposes through Research & Education projects. We upgraded the TRT kit using the aluminum profile and truss and isogrid structures for a high-end optical test device that can be used for prototyping of precision telescopes or satellite optical systems. Thanks to the substantial aluminum profile and lightweight design, mechanical deformation by self-weight is reduced to maximum 67.5 ㎛, which is an acceptable misalignment error compared to its tolerance limits. From the analysis results of non-linear vibration simulations, we have verified that the kit survives in harsh vibration environments. The primary mirror and secondary mirror modules are precisely aligned within 50 ㎛ positioning error using the high accuracy surface finished aluminum profile and optomechanical parts. The cross laser module helps to align the secondary mirror to fine-tune the optical system. The TRT kit with the precision aluminum mirror guarantees high quality optical performance of 5.53 ㎛ Full Width at Half Maximum (FWHM) at the field center.

• 한국항공우주학회지
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• 제32권8호
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• pp.129-137
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• 2004

본 연구에서 시험부 크기 $30mm{\times}35.6mm$, Run Time 20초인 소형-저가의 초음속 풍동을 개발하였다. 개발원 교육용 초음속 풍동은 단속적 불어내기식형이며 , 노즐 블록 교체형으로 설계되었다. 본 연구를 통하여 초음속 풍동에 사용되는 대형-고가의 기계장비를 기존 소형의 상용 제품으로 대체하여 제작 단가를 낮추었다. 그리고 초음속 풍동의 핵심 기술인 노즐 설계를 비롯한 전체적인 초음속 풍동 설계 기술을 확보하였다. 풍동 시험부에서의 초음속 유동장 형성 및 유동 안정성에 대한 성능검증 실험을 수행하였다.

• 전기전자학회논문지
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• 제24권4호
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• pp.1148-1155
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• 2020

Fire must be extinguished as quickly as possible because they cause a lot of economic loss and take away precious human lives. Especially, the detection of smoke, which tends to be found first in fire, is of great importance. Smoke detection based on image has many difficulties in algorithm research due to the irregular shape of smoke. In this study, we introduce a new real-time smoke detection algorithm that reduces the detection of false positives generated by irregular smoke shape based on faster r-cnn of factory-installed surveillance cameras. First, we compute the global frame similarity and mean squared error (MSE) to detect the movement of smoke from the input surveillance camera. Second, we use deep learning algorithm (Faster r-cnn) to extract deferred candidate regions. Third, the extracted candidate areas for acting are finally determined using space and temporal features as smoke area. In this study, we proposed a new algorithm using the space and temporal features of global and local frames, which are well-proposed object information, to reduce false positives based on deep learning techniques. The experimental results confirmed that the proposed algorithm has excellent performance by reducing false positives of about 99.0% while maintaining smoke detection performance.

• 정보교육학회논문지
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• 제10권1호
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• pp.1-12
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• 2006

교육에 있어 평가는 교육 주체뿐만 아니라 때로는 국민적인 관심사가 된다. 최근 교육인적자원부에서 제시하는 개혁안과 사회의 요구를 반영할 때, 숫자 하나로 학생의 모든 성취 정도를 나타내는 전통적인 검사 방법은 한계가 있다. 이에 따라 구성주의를 바탕으로 교육 평가 분야에 수행평가가 대두되었으며, 포트폴리오 (Portfolio)는 수행평가 철학을 구현하는 대표적이고 효율적인 한 방법이다. 포트폴리오 평가 기법의 많은 장점과 함께 단점 역시 지적되었는데, 물리적 공간과 비용의 문제 그리고 자료접근과 검색의 비효율성 등이 그것이다. 이런 포트폴리오의 단점을 극복하면서 학생들의 ICT (Information & Communication Technology) 활용능력 향상까지 도모할 수 있는 것이 전자 포트폴리오 (Electronic Portfolio) 평가 기법이다. 본 연구의 목적은 전자 포트폴리오 평가 절차 모형을 개발하고, 각 단계별로 지침이 될 수 있는 구체적인 활동을 제안하는 것이다. 개발된 포트폴리오 평가 절차 모형은 준비, 개발, 평가, 활용의 네 단계로 이루어져 있으며 각 단계별로 교사와 학생의 활동을 구분하여 제시하였다. 본 모형은 교사, 학생, 학부모에게 포트폴리오 평가에 대한 안내를 제공하고, 교사에게는 평가과정 전반에 걸친 지침을 제공할 것으로 기대한다.