• Journal of the Korean Society for Heat Treatment
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• v.2 no.4
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• pp.19-26
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• 1989

Fundmental fatigue crack propagation tests with C-T type specimens were conducted at various load ratios (R) such as 0.1, 0.3 and 0.5 in T6 and Thermomechanically treated (TMT) conditions of 7039 Al alloy. Better mechanical properties from monotonic test as well as fatigue crack propagation were obtained by TMT process owing to uniform distribution of fine microstructures and non-existence of precipitation free zone (PFZ). Through the measurement of Kop and ${\Delta}K$ at various R the concept of effective stress intensity factor range ratio, U was reviewed to asses the load ratio effect on fatigue crack propagation. A relationship between U and variables such as ${\Delta}K$ and R was obtained empirically. This may enable us to predict ${\Delta}K_{eff}$ that is of critical importance for prediction of fatigue crack propagation rate.

• Journal of Engineering Education Research
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• v.16 no.2
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• pp.37-49
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• 2013

In this paper, articles in full body of JEER in Korea and JEE in U.S. were classified into two categories- Research area and Key words-to endeavor a comparative study of the engineering education research(EER) topics and their temporal changes. In the recent 4 year term, 'Accreditation of Engineering Education' and 'Courses & Curriculum' were the most common key words appearing in JEER and 'Researches on EER' and 'Learner's Factor' in JEE. If we put curriculum/teaching materials/teaching as the input elements and learning/assessment as the output elements for education achievement, JEE demonstrates that many of the research topics have shifted from input to output in the recent years, while JEER research is in the transient stage.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.55-58
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• 2009

본 연구는 주관적인 사용자의 감성을 객관적으로 정의하여 2차원 감성 모델에 의한 터치폰의 GUI 디자인 요소에 대한 디자인 가이드라인을 제시하고자 한다. 본 연구는 다음과 같은 단계로 연구를 진행하였다. 첫 번째 단계로 그루밍(Grooming) 사용자들의 라이프 스타일을 조사하여 Norman(2002)에 의거한 감각적, 행태적, 그리고 심볼적 세 가지 레벨의 감성요소를 추출하였다. 두 번째 단계로 Russell(1980)의 28개 감성 어휘와 세 단계 감성과의 관계성을 설문하여 감성모델을 구현하였다. 마지막으로 요인분석을 이용하여 대표 감성 어휘를 도출한 후 감성적 터치폰의 GUI(Graphic User Interaction) 디자인 요소를 제시함으로써 사용자의 감성이 반영된 인간 중심적인 제품 디자인을 위한 가이드라인을 제안한다.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.53-56
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• 1987

Gyroscope is a key sensor for inertial navigation system (INS) which is a navigational instrument necessary to guide and control a free vehicle, and an important instrument for defense, aeronautical, and space industries that is and will be actively involved. In this study, design parameters, scale factor and linearity, of torquer which is one of the components of two degree of freedom dynamically tuned gyroscope (DTG) are presented. The magnetic circuit of torquer is so complicated that it is difficult to analyze it with analytic method. Thus these parameters are calculated by using finite element method with analysis of magnetic vector potential for axisymmetric 3-dimension magnetic field.

• Mycobiology
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• v.39 no.2
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• pp.121-124
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• 2011

The cDNA of endo-1,$4-{\beta}-xylanaseA$, isolated from Phaenerocheate chrysosporium was expressed in Pichia pastoris. Using either the intrinsic leader peptide of XynA or the ${\alpha}$-factor signal peptide of Saccharomyces cerevisiae, xylanaseA is efficiently secreted into the medium at maximum concentrations of 1,946 U/L and 2,496 U/L, respectively.

• Journal of Family Resource Management and Policy Review
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• v.6 no.1
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• pp.73-85
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• 2002

This study examined which factors influence the parental borrowing for children's college education in the U.S. A double-hurdle model was applied to analyze both the parents’decision to borrow and the amount of borrowing. Parents’income and total costs of college attendance had significant positive effects on both the decision to borrow and the amount borrowed. Students’income, parents’cash and savings had significant negative impacts on the amount borrowed, while home equity and the students’expected future income were significant positive factors. Greater amounts of grants significantly increased the probability of borrowing, but reduced the loan amount. Parents with smaller household size, and those who were college graduates were more likely to borrow. White parents borrowed greater amounts than did their non-White counterparts. The age of the student was a significant negative factor in the probability, as well as the level, of borrowing.

• Journal of Ocean Engineering and Technology
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• v.2 no.1
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• pp.116-124
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• 1988

해양구조물의 원통조인트에 대한 피로 수명 산출이 전통적으로 실험적 방법에만 의존해 왔음은,원통조인트의 구조가 복잡하여 용접부위 균열의 응력확대 계수 계산이 거의 불가능 했든 것이 주 원인이었다. 최근에 유한요소 3차원 모델을 이용한 계산방법이 개발되어 심히 구조적으로 복잡한 표면 균열의 응력확대계수 산출이 용이하게 되었다. 해양 구조물의 원통조인트에 대한 피로 수명 산출법을 개발하기 위한 연속되는 3부작의 제1부로서 본 논문은 X형 원통 조인트 용접주위 표면 균열의 응력확대 계수 거동을 분석하고 있다. 분석결과를 이용하여 응력확대계수를 엄격한 방법에 의해 계산하였다. 계산된 응력확대계수를 구조적인 관점에서 해석하고 있다.

• Structural Engineering and Mechanics
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• v.36 no.6
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• pp.669-678
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• 2010

In general means, the stress concentration problem of elastic plate with a rectangular hole can be investigated by numerical methods, and only approximative results are derived. This paper deduces an analytical study of the stress concentration due to a rectangular hole in an elastic plate under bending loads. Base on classical elasticity theory and FEM applying the U-transformation technique, the uncoupled governing equations with 3-DOF are established, and the analytical displacement solutions of the finite element equations are derived in series form or double integral form. Therefore, the stress concentration factor can then be discussed easily and conveniently. For the plate subjected to unidirectional bending loads, the non-conforming plate bending element with four nodes and 12-DOF is taken as examples to demonstrate the application of the proposed method. The inner force distribution is obtained. The solutions are adequate for the condition when the hole is far away from the edges and the thin plate subjected to any transverse loadings.

• Journal of Microbiology and Biotechnology
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• v.32 no.3
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• pp.317-323
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• 2022

Solid-state fermentation using hulled barley was carried out to produce enzymes and β-glucan. The one-factor-at-a-time experiments were carried out to determine the optimal composition of the basal medium. The modified synthetic medium composition in liquid-state fermentation was determined to be 70 g/l hulled barley, 0 g/l rice bran, 5 g/l soytone, and 6 g/l ascorbic acid. Optimal pretreatment conditions of hulled barley by solid-state fermentation were evaluated in terms of maximum production of fungal biomass, amylase, protease, and β-glucan, which were 1.26 mg/g, 31310.34 U/g, 2614.95 U/g, and 14.6% (w/w), respectively, at 60 min of pretreatment condition. Thus, the solid-state fermentation process was found to enhance the overall fermentation yields of hulled barley to produce high amounts of enzymes and β-glucan.

• KDI Journal of Economic Policy
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• v.43 no.2
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• pp.53-79
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• 2021

The recession caused by the COVID-19 crisis has features that could disproportionately harm female employment. Risk of infection and social distancing measures may have disrupted jobs in face-to-face industries, which have traditionally hired more women than men. School closures and a consequent increase in childcare and homeschooling demands may have discouraged labor market participation by working mothers. Using the Economically Active Population Survey, I examine how female employment was affected by each factor. I find that the gender gap in the Employment to Non-participation (E to N) transition rates is twice as large as the gap in the Employment to Unemployment (E to U) transition rates. Women's overrepresentation in the face-to-face industries accounts for most of the gap in the E to U transition but only a third of the gap in the E to N transition. The rise in non-participation is especially pronounced among married women aged 39-44, the group most likely to have elementary-school-age children.