• 한국수학교육학회지시리즈E:수학교육논문집
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• 제22권3호
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• pp.369-382
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• 2008

서울산업대학교에서 2005학년도부터 실시한 대학수학의 수준별 수업 진행 상황과 그 결과에 따른 학생들의 학업성취도를 분석하고, 향후 보완 추진해야할 과제들과 대학수학 교육의 발전을 위한 방법을 제안하고자 한다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권8호
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• pp.399-403
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• 2006

An accurate constant output voltage provided by the analog memory cell may be used by the low power oscillator to generate an accurate low frequency output signal. This accurate low frequency output signal may be used to maintain long-term timing accuracy in host devices during sleep modes of operation when an external crystal is not available to provide a clock signal. Further, incorporation of the analog memory cell in the low power oscillator is fully implementable in a 0.35um Samsung standard CMOS process. Therefore, the analog memory cell incorporated into the low power oscillator avoids the previous problems in a oscillator by providing a temperature-stable, low power consumption, size-efficient method for generating an accurate reference clock signal that can be used to support long sleep mode operation.

• 소음진동
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• 제10권4호
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• pp.629-635
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• 2000

Wheel /rail interaction has been known as a major source of railway noise. In this paper, a low noise wheel structure is developed and its effect on noise reduction is investigated. The developed low noise wheel employees a rubber material inserted into a steel rim or mounted on the wheel surface. Since the low noise wheel has low stiffness and high damping ratio compared to a solid wheel, the measurement results show that it reduces the rolling and squeal noise. It turns out that the proposed wheel could reduce interior noise level by 4∼5dB(A) and vehicle vibration level by 7∼10 dB. Although the proposed structure seems to be promising in noise reduction of railway vehicles, the low noise wheel is to be verified in endurance and cost effect.

• 보건교육건강증진학회지
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• 제25권5호
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• pp.39-51
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• 2008

본 연구의 목적은 한국복지패널데이터의 흡연음주 현황과 관련 건강위험요인을 연구분석 하는 데 있다. 성, 연령, 외래의료이용횟수, 주관적 건강수준, 흡연수준, 음주수준, 우울증상, 저소득 등이 주요 분석변수였다. 복지패널데이터에 있는 건강변수가 제한된 관계로 분석도 제한적으로 실시되었다. 흡연율은 성별 차이가 컸고, 특히 연령이 젊을수록 높았으며, 저소득 층에서 더 높았다. 20-29세 연령층의 경우 흡연율이 일반계층은 23.3%였고, 저소득층에서는 25%였다. 20대 남성흡연율은 일반가구 48.1%, 저 소득가구 47.4%로 큰 차이가 없었으나 30대에서는 일반가구 60.7%, 저 소득가구 71.0%로 가장 큰 차이를 나타내었다. 여성의 경우 전 연령층에서 저 소득층이 흡연율이 높았고 50대에서 일반가구 3.9%, 저 소득가구 10.5%로 가장 큰 차이를 나타내었다. 음주율 특성을 보면 일반가구에서 음주율은 오히려 높게 나타났는데, 일반가구는 전혀 안마신다는 비율이 36.7%, 저 소득가구는 58.4%였다. 흡연과 고위험 음주문제 모두에서 성별, 연령과 교육수준, 소득계층 등의 인구사회학적 변수가 유의한 영향요인인 것으로 분석되었다. 남성, 이십대 및 삼십대 연령층, 고졸이하의 학력, 저소득 가구일수록 건강위험요인의 정도가 높은 것을 알 수 있었다. 전반적으로는 여성의 건강이 더 안 좋다. 저소득층 여성의 흡연율은 일반가구 여성의 흡연 율보다 높은 것으로 나타났다. 저소득층일수록 건강위험행동을 경험하고, 더 많은 의료서비스 경험이 있는 것으로 나타났다. 한편 보건소 이용경험은 저소득층은 4.6%, 일반계층은 1% 정도였다. 2005년도의 건강영양조사결과에서도 건강수준이나 활동제한의 정도가 각 연령별로 분석해도 저소득층일수록 더 안 좋은 상태인 것으로 나타난 바 있다. 본 연구에서 흡연과 음주와 관련된 심리적 요인과 소득수준의 요인이 유의한 영향력이 있음을 알 수 있었다. 특히 건강위험행동과 관련하여 개인의 심리적 요인에 대하여 향후 심층적인 연구를 할 필요가 있다. 사회경제적 어려움으로 인하여 개인이 경험하는 우울과 같은 심리적 요인이 건강위험행동을 지속하게 하는 요인이 될 수 있기 때문이다.

• Asian Journal of Business Environment
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• 제9권1호
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• pp.21-28
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• 2019

Purpose - The purpose of this paper is to investigate the relationship between corporate social responsibility disclosure (CSRD) and investment-cash flow sensitivity, which is a surrogate for financing constraints. Research design, data, and methodology - Taking China's A-share listed companies between 2009 and 2016 as a sample, this paper empirically tests the relationship between CSRD and investment-cash flow sensitivity by Panel VAR model. By introducing the orthogonal impulse response function, this paper distinguishes the fundamental factors and financial ones that affect corporate investment behavior. Results - Findings indicate that: (1) investment-cash flow sensitivity of firms with low level of CSRD is significantly lower than that of firms with high level of CSRD; (2) the orthogonal impulse response of corporate investment to cash flow in firms with high level of CSRD is significantly different from zero, but it is not significant in firms with low level of CSRD; (3) for firms with low level of CSRD, 0.7% of corporate investment volatility can be explained by the change in cash flow, which is lower than that of firms with high level of CSRD (1.1%). Conclusions - Corporations disclosing more and higher quality CSRD are often those faced with financing constraints. Voluntary disclosure can help them alleviate information asymmetry and financing constraints.

• 전기학회논문지
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• 제56권6호
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• pp.1071-1079
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• 2007

In this paper, a novel space vector control method for isolated multi-level inverter using 3-phase low frequency transformers is proposed. This method is based on the simplification of the space-vector diagram of a five-level inverter using calculated table into fully programming method. The execution time of the proposed method is about same as that of the method using calculated table. Also, the proposed method is easily applied to other case level inverter. We applied this method into the 3-phase IHCML inverter using common arm. It makes possible to use a single DC power source due to employing low frequency transformers. In this inverter, the number of transformers could be reduced compare with an exiting 3-phase multi-level inverter using single phase transformer. In addition, this method generates very low harmonic distortion operation with nearly fundamental switching frequency. Finally, We tested multi-level inverter to clarify electric circuit and reasonableness through Matlab simulation and experiment by using prototype inverter.

• Journal of Nutrition and Health
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• 제28권10호
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• pp.967-975
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• 1995

To investigate effects of dietary fish oil and vitamin E level on the tissue levels of vitamin E and vitamin A and to see which tissue is sensitive to lipid peroxidizability, male Sprague-Dawley rats were fed experimental diets composed of either menhaden oil or soybean oil nad either low(equivalent to 17 mg $\alpha$-tocopherol) or high (equivalent to 140mg $\alpha$-tocopherol) vitamin E level for 4 weeks. Palsma TBARS per mg lipid was significantly elevated in rats fed fish oil with low vitamin E level compared to soybean oil-fed rats. TBARS levels of liver, heart, kidney and liver microsomes were also increased by feeding fish oil with low vitamin E level. Plasma TBARS level was significantly correlated with TBARS levels of liver, heart, kidney and liver microsome. Plasma vitamin E level of groups with vitamin E supplementation was elevated significantly as compared to the those without vitamin E supplementation, whereas vitamin E levels of liver, heart and kidney were not changed significantly. Plasma TBARS was negatively correlated with plasma vitamin E(r=0.5763, P<0.001) and A(r=-0.4523, P<0.01) and seems to be a good indicator of in vivo lipid peroxidative stress.

• 한국학교수학회논문집
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• 제2권1호
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• pp.43-53
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• 1999

Two (second-grade) classes of Yu-song middle school were chosen to research the effect of the visualization in the learning of probability calculation at a middle school. One class, as an experiment class, was taught the probability calculation of probability unit by the visualization learning and the other, as a controlled class, was taught it by the traditional lecture, and then through the writing tests there was a verification on the effect of right after test and the delaying test after 3 weeks to examine the learning effect of high- and low-level groups. It was difficult for the students to visualize the problems of the probability calculation, but I suggested simple models to the students and helped them to learn meaningfully. As a result of this study, there showed statistically significant difference in high-level group in the right after test.(P< .05) In the delaying test after 3 weeks, there also showed statistically significant marks only in high-level group.(P< .05) The visualization in the learning of probability calculation took more affirmative effect in the experiment class than the comparative class only in high-level group. The students in low-level group has difficulties in the visualization activities, but all the students in high-and low-level group thought the visualization was a great help to them in learning probability calculation.

• 수산해양교육연구
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• 제16권1호
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• pp.11-20
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• 2004

The purpose of this study was to analyze of career exploration and career decision-making by identity statuses(diffusion, foreclosure, moratorium, achievement) of vocational high school students. The research questions were formulated as follows. (1) Is there a difference in identity statuses by level of the career exploration? (2) Is there a difference in identity statuses by level of the career decision-making? (3) How much identity statuses-identity diffusion, identity foreclosure, identity moratorium, identity achievement-effect to the career exploration and career decision-making? 255 vocational high school students in Pusan were sampled. For the statistical analysis, Oneway, analysis of covariance structure by AMOS 4.0 was applied. The results of the study were as follows. (1) The identity diffusion was low in the level of career exploration, but the identity moratorium and achievement were high in the level of career exploration. (3) The identity diffusion was low in the level of career decision-making, but the identity achievement was high in the level of career decision-making. (4) The identity diffusion effected to negatively career exploration and career decision-making, identity foreclosure effected to low positively career exploration and career decision-making, identity moratorium effected to positively career exploration but negatively career decision-making, identity achievement effected to positively career exploration and career decision-making.

• 산업융합연구
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• 제13권3호
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• pp.57-76
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• 2015

The purpose of this paper is to examine the moderate effects of self monitoring and the ways of thinking on the relationships and the moderate effects of brand credibility and brand attachment on the relationships between the negative information about a brand and the customer attitude holistic and analytic on the relationships between the negative information about a brand and customer attitude. To accomplish these purposes, this research divided negative information about a brand into corporate ability and corporate social responsibility. In addition, research also divided product type into functional product and symbolic product. participants are classified as having Low or High self monitoring. and the ways of thinking divided into holistic and analytic on the relationships between the negative information about a brand and customer attitude. The following are the summary of hypothesis test: (1)the consumers with low(high) level of self monitering are more likely to reveal high level of preference for negative information of corporate ability. (2)the consumers with analytic(holistic) ways of thinking are more likely to reveal high level of preference for negative information of corporate ability. (3)the consumers with low(high) level of self monitering are more likely to reveal high level of preference for functional product. (4)the consumers with analytic(holistic) ways of thinking aren't more likely to reveal high level of preference for functional(symbolic) product.