• Journal of Korean Elementary Science Education
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• v.40 no.3
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• pp.311-325
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• 2021

Modern society demands a new science teacher image. Compared to other school ages, elementary school students are the time when the teacher's influence plays a large role and is the time when they first encounter science subjects. The role of science teachers is very important as the starting point for the initial image of science learning and attitudes toward science by elementary science teachers. Therefore, it is very important to correctly establish an image of an elementary science teacher. The purpose of this study is to analyze the images of science teachers that elementary school students prefer and avoid according to their class situation. To this end, 534 elementary school students were divided into five classes: class type, class material presentation method, subject instruction method, subject content explanation method, and class atmosphere, and the image of science teacher who prefers and avoids is described in an open format. Concepts presented by elementary school students were analyzed using Semantic network analysis. The conclusions of this study are as follows. First, the image of a science teacher preferred or avoided by elementary school students was determined according to how the science teacher did the class. Second, elementary school students prefer activity-oriented classes such as experimental classes, and there is a need for classes to be conducted in this manner. Lastly, small changes and efforts of teachers in teaching methods are needed so that changes to science classes preferred by elementary school students can be achieved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.121-125
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• 2003

A switch box is metal box for electric wire pipes in building. In manufacturing this box, the first press is used to mold and the second to fifth presses are used to process four-sides of a box. So four presses, four molds and four workers are needed. This leads to raise the manufacturing cost including machine lease rent, molding fee, and wages. To make matters worse, the roaring sound, vibration, and dangers of safety accidents make employees avoid from working that job. To solve this problem, a new Handling Mechanism and a cam die which combined four-die-involving processes into one die process were developed. That results job automation of the Job with one press and one die. The job avoidance problem is solved and manufacturing cost is reduced as well.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.877-880
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• 2017

Impeller blades in the centrifugal compressor are subjected to static loads due to the high-speed rotation and steady aerodynamic forces. At the same time, aerodynamic excitations by the interaction between the impeller and the diffuser vanes(DV) periodically excite the impeller blades in resonant conditions, which may lead to high cycle fatigue (HCF) and eventually result in failure of the blades. In order to predict the structural response accurately, the aerodynamic excitation and the major resonant conditions were predicted by performing the unsteady flow analysis and modal analysis using ANSYS. Next, a unidirectional forced vibration analysis was performed by using fluid-structure interaction (FSI) method, and the safety of HCF was evaluated based on the results.

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.136-148
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• 2006

A foundry makes various machinery parts made by iron. For manufacturing machinery parts, they usually uses wooden mold with molding sand and pour the molten iron into wooden mold through inlet. A foundry have many processes including Furan process, In Furan process workers prepares a wooden mold in the molding sand. So they fixes wooden mold in sand housing and then they fill the molding sand in the sand housing. Molding sand should be sticky enough to sustain the shape of wooden mold, so several materials are needed to prepare the suitable molding sand. The first step of Furan process is making the molding sand with molding sand and Voltaic Organic Compounds (VOC) and the second step of Furan process is pour the molding sand into the wooden molding housing. This two step of process generated noxious VOC and various size of dust. So the process is very dirty and dangerous one. Because of these, Workers frequently shrink out of the plant. The company related with foundry usually faced on the difficult situation for engagement and always have shortage of hiring problem. Through this study, we developed a system which removes toxic VOC and dust simultaneously. We design and construct real system and install it at real plant. Before setting up this system, the working surroundings VOC (for formaldehyde) 15 ppm and Dust(for $PM_{10}$) $8,000{\mu}g/m^3$. After setting up this system, working surroundings is improved by VOC (for formaldehyde) 0 ppm, Dust(for $PM_{10}$) $4{\mu}g/m^3$, and the work evasion factor is removed. So we contribute to solve hiring problem of this company and increasing the productivity also.

• Journal of Industrial Convergence
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• v.19 no.6
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• pp.21-35
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• 2021

The purpose of this paper is to examine how demand for labor affects the job seeker's decision on the level of investment in education. In the current paradigm of economic growth in which innovations and technological developments generally weaken the strength demand for labor and increases the uncertainty related to employment, this paper provides a theoretical framework that can be used as a basic framework in understanding the decision of investment in education in varying conditions of demand for labor. The following are the findings of this paper. First, the level of investment in education can generally be regarded to be higher as the demand for labor exacerbates but for the job seekers with a certain characteristic. Second, the Arrow-Pratt absolute risk-aversion measure is the characteristic of the job seeker that determines in what direction the job seeker changes in the level of investment in education, For an arbitrary level of demand for labor there exists a certain threshold which determines the minimum degree of risk-aversion required for the job seeker's Arrow-Pratt should go over to increase the level of education as demand for labor weakens. Third, the job seekers lower the level of education even though the demand condition in labor markets weakens if the compensation function does not depend on the level of education. This is surprising because it turns out that one of the reasons why job seekers invest in education is that they want to be recognized in their compensation for their level of education even when more education still raises the probability of employment.

• The Korean Journal of Financial Management
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• v.24 no.3
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• pp.133-152
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• 2007

In this paper, we examine a portfolio selection model in which a safety-first investor maximizes expected return subject to a downside risk constraint. We use the Value-at-Risk as the downside risk measure. We exploit the fact that returns are fat-tailed, and use a semi-parametric method suggested by Jansen, Koedijk and de Vries(2000). We find a more realistic asset allocation than the one suggested by the literature based on the traditional mean-variance framework. For the robustness check, we provide empirical analyses using empirical quantiles. The results highlight that for optimal portfolio selection involving downside risks that are far in the tails of the distribution, our mean-VaR model with a fat-tailed distribution is superior.

• Korean Deer Journal
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• no.16
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• pp.13-25
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• 1992

사슴 수입개방으로 외국 사슴 수입 추진이 활발해짐에 따라 국내 사슴 분양을 기피하고 수입사슴에 대한 관심이 높아가고 있습니다. 그러나 수입된 사슴이나 수입될 사슴들이 수출국에서 종록이나 우수사슴(녹용 생산용)으로 기른 것이 아니고 녹육생산을 목적으로 개발된 일반 사슴으로 알려지고 있으며 혈통을 증명할 혈통서 없는 상업성(저질) 사슴 수입이 계속될 전망입니다. 따라서 본회는 품종개량과 녹용 생산성을 높이고 상업성 사슴수입을 저지하는 한편 국내 사슴의 유통활성화 대책으로 우수사슴 발굴규정, 사슴유통준칙, 지정분양장 규칙을 제정했으므로 모든 양록인의 참여와 활용을 바라는 바입니다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.257-263
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• 2003

방제는 재배작물에 발생하는 병충해를 최소화하여 농산물의 품질을 향상시키고 생산성을 증대시키는 중요한 관리 작업이며, 작물을 재배하는 동안에 여러 번 작업해야하며 노동 강도가 크고 농약중독 위험 때문에 농민이 기피하는 작업이다. 방제 방법에는 화학적 방제와 생물학적 방제, 농업적 방제, 기계적 방제 등 여러 방법이 있다. 화학적 방제는 잡초나 해충, 균의 밀도가 경제적 피해 수준 이하에서 유지되면서 더욱 확산되지 않도록 천연 또는 인공 화학물질을 이용하여 병해충이나 잡초를 억제는 방제방법으로 현재는 물론 가까운 미래에도 주를 이룰 것으로 예상된다. (중략)

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.571-574
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• 2008

계량 습식방법으로 실험한 결과 다른 처리 방법과는 달리, 물리성과 환경성 모든 항목에서 적합함을 나타내었다. 그러므로 원예농업용 폐비닐의 저급물리성과 중금속등의 유해 물질 검출의 우려로 인한 사용기피를 조금이나마 불식하고 기존에 유해성분 검출로 토양이나 작물에 문제가 됐던 원예농업용 자재를 대체할 수 있는 자재로서의 가능성을 보였다고 할 수 있다.

• Nuclear industry
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• no.3_4 s.12
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• pp.49-51
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• 1983

미국의 소비자계몽단체인 $\lceil$미국과학${\cdot}$보건협회의$\rfloor$는 $\lceil$조사식품$\rfloor$이란 소책자를 발행했다. 이 소책자는 저선량방사선의 식품조사의 안전성은 명확하며 고선량조사의 경우에도 위험한 결과를 볼 수 없으므로 소비자는 조사식품을 기피한 필요가 없고 오히려 풍요로운 생활을 영위할 수 있게 하는 것으로 환영할만한 것이라고 강조하고 있다. 미국에서는 $83\~84$년중에 상업조사식품이 나올 것으로 전망되는데 소비자의 반응이 주목된다. 다음은 그 소책자의 개요이다.