• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.89-90
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• 2017

본 논문에서는 일사량 데이터를 이용한 태양광 부스트 컨버터의 MPPT 성능분석에 대한 연구를 제안한다. 실외 실험을 통해 일사계(Pyranometer)로 측정한 일사량 데이터와 그에 따른 태양광 패널의 출력 데이터를 검토하여 부스트 컨버터의 MPPT 성능을 테스트 하였으며, 측정한 일사량 데이터를 토대로 수행한 시뮬레이션과 실험결과를 비교 분석하였다.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.385-394
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• 2012

This study investigates whether earnings management behavior of chaebol firms differ from that of non-chaebol firms. The ownership structure of chaebol firms is characterized by the dominance of one largest shareholder and his family members who typically participate in the management of the firm directly or indirectly and influence most of the important management decision. This study adopts the random effect model and the hausman and talyor model, using a panel of 5092 firm-year over a period from 1991 to 2010 to control for potential heterogeneity and endogeneity that may cause sever bias. This study finds that there is no difference in accrual based earnings management level between chaebol firms and non-chaebol firms. However, chaebol firms appeared to engage less real earnings management that is known to negatively affect future earnings and share prices. The results are consistent when controlling for potential heterogeneity and endogeneity in the hausman and taylor model. The results may be of interest to various stakeholders, policy makers, standard setters and academic researchers.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2017.11a
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• pp.915-940
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• 2017

본 연구는 산업조직이론과 자원기반관점을 통합하여 사업 다각화에 대한 산업환경요인과 기술역량의 결정요인들로 구성한 통합모형을 설계하고, 제안한 모형을 스마트공장 ICT융합기술(애플리케이션 및 플랫폼 분야) 특허 출원기업 272개사의 6개년(2010년~2015년) 특허 및 재무데이터를 이용하여 실증적으로 분석하였다. 고정효과 패널모형을 분석한 결과, 기업의 사업다각화 의사결정에 영향을 미치는 요인들 가운데 기술경쟁력은 사업다각화 수준을 높이는 긍정적 효과가 검증되었다. 추가적으로 2단계 최소자승 고정모형을 분석한 결과, 출원특허수 보다 특허의 기술융합수준이 기술경쟁력을 증대시키는 유의미한 긍정적 효과가 있음을 검증하였다. 본 연구 결과에 근거하여 기업의 ICT융합기술자원 및 역량을 바탕으로 한 사업 다각화 전략기획방향과 정부 R&D 정책과 관련하여 융합기술자원의 사업화 지원방안에 대한 시사점을 제공하고자 한다.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.95-106
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• 2014

The outer surfaces of free form buildings contain panels with two-directional curvatures. To construct these panels, complex geometric surfaces should be divided into forms and sizes that can be manufactured and constructed efficiently. Because the bigger the curvatures of these panel, the more expensive the construction costs, these complex curvatures should go through optimal process of reinterpretation to minimize the curved surfaces with complex two-directional curvatures, which is called panel optimization. Small construction and design companies have trouble in calculating even rough estimate and cannot adjust expected construction cost of the panels based on comparison of design alternatives in conjunction with panel optimization process due to lack of knowledge and experience. This study conducts the research that can support designers' cost decision-making in the design stage of the free form buildings with respect to the panel optimization process. A 3D commercial application specialized to modeling free form shapes is used for the purpose.

• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.195-206
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• 2017

The purpose of this study was to identify factors affecting quality of health care. Methods: The data were derived from the 2011-2013 Korea health panel survey (beta version 1.0). The data were analyzed using SPSS 21.0 with descriptive statistics, ${\chi}^2$-test, and multiple logistic regression analysis. In general characteristics, common factors influencing the quality of health care were age, marital status, education level, and subjective health status. In variables related to health care utilization, unmet healthcare needs, and limitation of dental care utilization were the significant factors affecting quality of health care. The results of this study show that various factors influence quality of health care. These findings can be used to develop strategies to improve health care.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.178-186
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• 2019

Previous studies have shown the significant association between loneliness and game addiction. To determine the causal relationship between them, the present study utilized a series of autoregressive cross-lagged models to early adolescent panel data (N = 346) from KOCCA's Game User Panel Research. Results indicated that loneliness and game addiction, respectively, had relatively strong and stable autoregressive effects across four time points. Also, game addiction at a prior time increased loneliness at a later time, but loneliness was not significantly related to game addiction later in time. These results suggest that game addiction may cause loneliness, not the vice versa.

• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1397-1405
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• 2014

Usually unit-nonresponse or item-nonresponse occurs in the survey. In case the rate of nonresponse is high, the analysis ignoring nonresponse may cause the wrong effect. The characterization of nonresponse is required. In a cross-sectional data, it is possible to study the characteristics of item-nonresponse but it is hard to study the characteristics of the unit-nonresponse. In order to identify the characteristics of the unit-nonresponse, this study used the first-year student of middle schools in the Korea children and youth panel survey (KCYPS) data. We investigated the handling situation of nonresponse and analyzed the characteristics of the unit-nonresponse. Most of the papers applied the way of getting rid of nonresponse, so that there was little paper using weights. In this paper, we compared the results of the analyses depending on whether the weight is used or not. The method of using weights showed statistically significant results much more than that of removing. More discussion will be needed.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.616-625
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• 2018

The purpose of this study was to analyze the relationship between the BMI and suicidal ideation using Korean Health Panel data from 2009 to 2013 to identify risk factors for suicide. We conducted a logistic regression analysis using the R statistical package to analyze the relationship between the BMI and the suicidal ideation. The results of this study show that all models with BMI had a statistically significant as a significant variable. It was found that the obese group was more likely to suicide ideation than the other groups. Based on these results, we try to find social implications for suicide prevention and intervention.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.642-643
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• 2011

스마트그리드 구현에 실시간요금제 적용이 핵심으로 등장하고 있다. 실시간요금제 적용 시 전력수요의 변동을 시뮬레이션하기 위하여 2005년부터 2009년의 전자식전력량계 계량데이터를 이용하여 전력 수요의 가격탄력성을 구하였다. 가격탄력성을 산출하기 위하여 시계열 분석과 횡단면 분석을 동시에 수행할 수 있는 패널모형 분석을 적용하였으며, 국내 전기요금에 대하여 계약종별, 산업분류별 가격탄력성을 실시간 요금제에 대비하여 1시간 단위로 구하였다. 국내 전력수요의 가격탄력성은 계약종별 및 산업분류별로 대부분의 경우 -0.1 이내로 산출되어 가격탄력성이 매우 낮게 나타났다. 산업분류별로 가격탄력성을 산출함으로써 통계적 유의수준이 높게 나타났다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4259-4265
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• 2012

Digital technologies and raising problems in freeform building design and construction in Korea were examined in this paper. Three Korean building cases were researched by having interviews with experts and documentary survey for this purpose. The following problems and important points were drawn from this research. The necessity of panel optimization, significance of the secure file conversion, difficulties in securing constructability of freeform building and using of 3D data for manufacturing panels.