• Journal of the Korean Society of Child Welfare
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• no.55
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• pp.1-29
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• 2016

The purpose of this study was to investigate the influence of household income on children's academic achievement, and to identify the mediating effects of parental time and material investment in the relationship between the two variables. We utilized the third-wave data of the "Seoul Panel Study of Children Surveys(SPSC, 2006)". The major findings of the present study are as follows. First, the results show that household income has a positive influence on children's academic achievement. Second, parental material investment fully mediates the influence of household income on children's academic achievement. Among the variables representing parental material investment, the mediating effects of "purchasing of cognitively stimulating materials" and "participating in extracurricular activities' are found to be statistically significant. However, the two variables representing parental time investment ("parent activities with child out of home" and "parent involvement in school") do not have any significant influence on children's academic achievement. These results indicate that the influence of household income on children's academic achievement can be better explained by parental material investment rather than parental time investment. Implications for policy and practice are discussed.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.593-604
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• 2022

This study examines how auditors respond to labor investment inefficiency, specifically its impact on audit fees and audit hours. Using a sample of Korean firms listed on the Korea Stock Exchange from 2003 to 2018, our empirical results indicate that firms involved in inefficient investment in labor incur higher audit fees and audit hours. This implies that auditors consider inefficient labor investment to cause considerable business risk, thus requesting higher external audit fees to compensate for higher audit risk. Furthermore, auditors expend more time and effort while auditing those firms by expanding the audit procedures to reduce the audit risk to an acceptable level. Finally, this study provides empirical evidence on whether the investment inefficiency in labor, an important factor in firms' competitiveness, incur higher audit fees as well as audit hours.

• Environmental and Resource Economics Review
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• v.5 no.2
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• pp.253-278
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• 1996

본 연구는 전력사업에서 공급설비가 다양할 때 계절 시간대별 요금에서 최적투자 및 가격정책을 도출하기 위한 동태적 분석방법을 제공하는 데 있다. 이를 위하여 수요의 교차 가격탄력성을 고려한 동태적 모형을 설정하여 최대원리법(Maximum Principle)을 적용하였으며, 최적해 도출시 해석적 방법을 이용하여 모형의 수리적 해석에 대한 방법론을 제시하였다. 특히 순 사회편익을 목적함수로하고 이를 최대화하는 제어변수를 설비투자로하여 각 시간경로 (Time Path)에 따른 최적 가격이 단기 및 장기 한계비용과 어떻게 연관되는지를 보여주었다. 또한 제어변수인 설비투자가 계속적인 수요증가가 발생하는 시간경로에 따라 최적값이 어떻게 변하는지도 보여 주었다.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.661-670
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• 2012

In order to construct a profitable stock trading model, three considerations must be resolved in the model in integrated manner: profit principle, trader's conditions and stock market trends. Generally, a model will be developed through long experiences of stock trading that requires quite amount of expenses and time. This paper analyzes the issues involved in those considerations and proposes a road map for a trading model.

• Journal of Labour Economics
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• v.31 no.1
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• pp.135-162
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• 2008

This paper analyzes the impact of the mother's employment on her time investment in children's career decisions. Parental conversations with high school children and the parents' effects on children's career decisions are used as the proxies for the quantity and quality of time investment, respectively. For the empirical analysis, IV ordered-probit regressions are fitted to the KLIPS data. Other things being equal, the mother's employment does not cast any statistically significant impact on the quantity and quality of time input for children in high school. The effect of mother's employment on her time investment in children is positive for professional jobs while negative for nonprofessional jobs, but both lack the weight of statistical significance.

• Journal of Labour Economics
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• v.44 no.1
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• pp.169-204
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• 2021

We empirically verified whether there are different educational investment behaviors according to university admissions, using the Korean Education and Employment Panel data. The results are as follows; the average annual private education cost and the average amount of time spent studying alone per week of rolling admission type were lower than those of regular admission type. Also, rolling admission applicants had longer leisure and sleeping hours, such as watching TV and using computers. These results show the possibility that the university admission system will change the educational investment behavior. Furthermore, there is a possibility to induce the human capital investment to be made efficiently.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.63-76
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• 2016

Most previous studies found a positive relationship between the value of a firm and its R&D investments. This research measures the impact of the timescale of the R&D investment of a firm on its value using panel vector autoregression. By measuring the time required for R&D to impact the value of a firm, this study demonstrates that the lead time is an essential factor in the analysis of the effect of R&D investment on a firm's value. Our study finds that the length of the lead time varies according to the firm's size, industry concentration, and book to market ratio. Firms with a higher industry concentration show a shorter lead time. Also, firms with a larger size and higher book to market ratio generally show a shorter lead time.

• Proceedings of the Korean System Dynamics Society
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• 2008.05a
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• pp.25-56
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• 2008

본 연구는 경기순환이 심한 대규모 장치산업에서 투자행동을 어떻게 하는 것이 경기순환의 악영향을 최소화하면서 수익성을 극대화시키는가를 밝히는 것을 목적으로 한다. 대규모 장치산업에서는 호황기에 투자가 집중되는데, 완공까지 걸리는 시간 때문에 적정 수준을 넘어 투자가 이루어지고 이것이 다시 불황기를 불러옴으로써 경기순환이 반복된다. 위와 같은 장치산업의 특성을 반영하여 산업 동태모형을 구성하고 다양한 전략들에 대해 시뮬레이션을 수행하였다. 그 결과는 다음과 같다. 첫째, 일반적인 투자행동 방식인 시황순응 투자는 경기순환에 따른 수익의 부침을 초래할 뿐만 아니라 그것을 지속시킨다. 둘째, 가동률의 신축적 조절이나 설비구축기간의 단축과 같은 유연화 전략은 수익성의 제고와 수익 안정화에 크게 기여한다. 셋째, 수요가 정체된 시장에서는 일정한 투자가 바람직하고, 수요가 성장하는 시장에서는 시황에 역행하는 투자가 바람직하다. 결국 경기순환이 존재하는 산업에서는 유연화 전략 및 변형투자 전략을 통해서 투자행동을 경쟁업체들과 비동기화 시키는 것이 바람직하다.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.193-198
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• 1999

An asymptotic distribution of the ratio of two normal vectors is estimated. Using the estimated asymptotic distribution, an approximation method to estimate confidence interval of passenger's value of travel time is proposed. As a result of empirical study the 95% confidence interval of value of travel time of home-to-work trips in city of Seoul is estimated at ￦7341.25$\pm$1945.05/hr.

• Journal of Korea Port Economic Association
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• v.37 no.2
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• pp.119-131
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• 2021

Energy is an essential element in economic activity and people's lives, an important resource used by various industries, and the financialization of commodity markets has led to the growing importance of crude oil turning into the same asset as other assets. Accordingly, studies analyzing the correlation between energy prices and investor sentiment explain that investor sentiment affects oil prices through economic factors and speculation. In this study, we wanted to analyze whether the impact of the most representative changes in oil prices affects investor decision making, affecting investor sentiment, and applying wavelet consistency analysis to determine how energy prices relate to investor sentiment. Studies show that policies should be focused on policy and market changes because energy prices differ by time scale and investment sentiment should be more influential in the long term than in the short term.