• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1230-1234
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• 2009

산지하천 유역에서 돌발적으로 발생하는 홍수는 얼마나 신속히 예측할 수 있는 가에 따라 피해 정도가 크게 변화한다. 현재 국내에서는 도시하천과 일반 유역 등을 대상으로 하는 홍수 유출 해석이 대부분이며, 산지하천에 대해 특화된 홍수 유출 해석 시스템은 개발된 경험이 거의 없다. 우리나라에서는 60%이상을 차지하는 산지하천유역의 홍수유출해석을 수행할 때 외국의 지형에 맞게 개발된 여러 가지 경험식을 사용하여 집중시간을 산정해왔다. 평지가 많은 외국의 경험식으로 집중시간을 산정할 경우 산지하천의 지형적 특성을 충분히 고려하지 못하게 되어 실제 집중시간과 산정된 집중시간과의 차이가 크게 발생할 수 있다. 산지하천 유역에서 홍수유출해석에 필요한 집중시간 산정을 정확하게 하기 위하여 수문지형학적 기법으로 유역을 분석하고 지형적 특성을 포함하는 집중시간 산정기법을 검토하였다. 집중시간 산정기법은 GIS를 기반으로 유역 내 경사도와 경사향을 분석하고 유역의 최원점에서의 흐름경로를 설정하여 집중시간을 산정하는 방법이다. 개발된 모형을 평창강유역에 적용한 결과 유역 내 호우가 발생할 경우 집중시간을 단시간 내에 산정할 수 있어 신지하천 유역의 홍수유출을 해석하는데 도움이 된다는 것을 발견하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.143-147
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• 2013

This paper examines the impact of corporate governance structure on the cost of debt. Total sample is divided into the small sample, the medium sample and the large sample of equity concentration, based on the equity ownership of large shareholders. Our regression results show that foreign investors are not associated with the cost of debt in the small and medium samples of equity ownership, whereas foreign investors are significantly associated with the reduction in the cost of debt in the large sample of equity concentration. Academic implications of our findings are that as the ownership of dominating shareholders rises, they seek their private interests of perks causing an increase in agency costs and a decrease in firm's economic value, thus expanding borrowing costs. Practical business implications are that foreign investors may alleviate agency problem of dominating large shareholders in the firm through monitoring activities, thus enhancing the efficiency of business decision-makings.

• 한국도로학회지:도로
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• v.11 no.2
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• pp.54-64
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• 2009

• Journal of The Korean Association of Information Education
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• v.23 no.1
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• pp.65-72
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• 2019

As the importance of SW education grows, researches are actively being conducted to improve students' thinking skills. We conducted the group III tasks, which are experiencing and challenging in Beaver Challenge 2018, on 55 students of 5th grade in elementary school. Based on the result, we analyzed their average scores and defined whether each test has a correlation with possession of smartphone, computer familiarity, patience, concentration, and academic ability. The result indicated challenging task boosted the average score, the percentage of correct answers, and the percentage of correct answers for each level of difficulty. Moreover, the challenge task scores were higher as they higher computer familiarity, patience and concentration level. However, possession of smartphones and academic ability did not affect the score. Lastly, the scores were affected by different factors in different level of difficulty that patience factor in advanced level, computer familiarity factor in intermediate level, and concentration factor in beginner level. Thus, further researches are necessary to be conducted to expand the scope of the analysis through the diversification of test subject group and expansion of an evaluation area.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.155-156
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• 2008

This research measures EEG signals which are generating on head skin and extracts brain concentration level related with brain activity. We develop concentration wireless transmission system for controlling hardware by using this signal. Two channels are used for measuring EEG signal on front head and Biopac system with MP-100 and EEG100C was used for measuring EEG signal, amplifying and filtering the signal. LabView 8.5 was also used for FFT transformation, frequency and spectrum analysis of the measure EEG signal. As a result, ${\alpha}$ wave, ${\beta}$ wave, ${\theta}$ wave and ${\delta}$ wave were classified. we extracted the concentration index by adapting concentration extraction algorithm. This concentration index was transferred into lego automobile device by wireless module and applied for BCI application.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.41-46
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• 2009

This research measures EEG signals which are generating on head skin and extracts brain concentration level related with brain activity. We develop concentration wireless transmission system for controlling hardware by using this signal. Two channels are used for measuring EEG signal on front head and Biopac system with MP100 and EEG100C was used for measuring EEG signal, amplifying and filtering the signal. LabView 8.5 was also used for FFT transformation, frequency and spectrum analysis of the measured EEG signals. As a result, SMR wave, Mid-Bata wave, $\Theta$ wave classified. We extracted the concentration index by adapting concentration extraction algorithm. This concentration uldex was transferred into logo automobile device by wireless module and applied for BCI application.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.513-514
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• 2016

Recently, many researches has performed on human brain wave actively. In order to analyze these brain waves using EEG(electroencephalography) sensors collect EEG data and EEG can be analyzed by using a frequency analysis of the EEG. In this paper, we performed EEG analysis that NeuroSky's mindwave mobile EEG sensor collects brain wave data and analyze the delta, theta, alpha, SMR, beta wave using a frequency analysis of collected EEG. Target of this study is analysis of what kind of relationship between concentration and brain wave in frequency domain. By these analysis, we can analyse not only the commonly known close relationship between concentration and beta wave but also analyse correlation of other frequency components. Furthermore our research result will be contribute to studies to be more advanced form of brain wave analysis.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.2
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• pp.24-35
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• 2019

In this study, a hotspot analysis was conducted to suggest a new method for interpreting soil heavy-metal contamination data of abandoned metal mines according to statistical significance level. The spatial autocorrelation of the data was analyzed using the Getis-Ord $Gi{\ast}$ statistic in order to check whether soil heavy metal contamination data showing abnormal values appeared concentrated or dispersed in a specific space. As a result, the statistically significant data showing abnormal values in the mine area could be classified as follows: (1) the contamination degree and the hotspot value (z-score) were both high, (2) the contamination degree was high but the z-score was low, (3) the contamination degree was low but the z-score was high and (4) the contamination degree and the z-score were both low. The proposed method can be used to interpret the soil heavy metal contamination data according to the statistical significance level and to support a rational decision for soil contamination management in abandoned mines.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.226-226
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• 2020

최근 지구온난화에 따른 기후변화로 인해 집중호우와 태풍의 영향으로 토석류를 동반한 산사태가 빈번하게 발생하고 있다. 산지에서 짧은 시간동안 강우가 집중되어 발생하는 토석류는 고수위의 홍수파를 형성하며 유목 및 흙, 자갈 등이 함께 유동하여 주변도로와 하류지역의 민가나 하천구조물에 큰 피해를 발생시킨다. 특히 강원도 지방도로의 경우 대부분이 산지와 급경사지로 이루어져 있어 집중호우시 산사태나 토석류에 매우 취약한 실정이다. 이러한 피해를 사전에 예방하기 위해 국내에서는 부처별로 다양한 풍수해 관련 재해지도를 작성하여 제공하고 있지만 표준모델이 없고, 서로 다른 형태의 지도를 관리하고 있어 재난 발생 시 도로관리에는 효율적인 활용이 어려운 실정이다. 따라서 본 연구에서는 재난 시 효율적인 지방도로 관리를 목적으로 다양한 재해지도의 중첩을 실시하였다. 또한 도로에서 빈번하게 발생하는 재해를 분석한 결과 산사태와 토석류가 높은 비중을 차지하였으며, 해당 재해지도를 중첩하여 지방도로 중심의 재해지도를 작성하였다.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.433-440
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• 2015

This study was conducted to examine mediative effects of two factors, emotion control and thinking control, in the relationship between avoid fusion and attention. Participants (308 high school students) were asked to complete a questionnaire which contains items to measure some psychological properties such as emotion control (EC), thinking control (TC), avoidance avoid fusion (CF), conceration(Co) and learning attitude(LA). Structural equation model analysis showed that 8 of modified 9 paths were statistically significant; CF to Co and TC, TC to EC, Co, and LA, EC to Co and LA, and Co to LA. Limitations and suggestions were mentioned in the discussion.