• 응용통계연구
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• 제31권1호
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• pp.123-137
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• 2018

비선형 혼합효과 모형은 다양한 분야에서 반복 측정 자료를 분석할 때 주로 사용된다. 비선형 혼합효과 모형은 개체 내 변동(intra-individual variation)에 대해 고려하는 제 1단계 개별수준모델(individual-level model)과 개체간 변동(inter-individual variation)에 대해 고려하는 제 2단계 개체군모델(population model)의 두 단계로 구성되어 있다. 비선형 혼합효과 모형의 첫 번째 단계인 개별수준모델은 비선형 회귀모형의 모수를 추정하는 것으로 일반적인 비선형 회귀모형과 같고, 주로 보통최소제곱추정 방법을 사용하여 모수를 추정한다. 그러나 최소제곱추정방법은 가정된 비선형 함수가 자료에 의해 명시적으로 드러나지 않는 경우 모수의 추정값과 그 표준오차가 극단적으로 커지는 문제가 발생할 수 있다. 본 논문에서는 최근에 비선형 회귀모형에서 제안된 능형회귀(ridge regression) 방법을 비선형 혼합효과 모형의 제 1단계 개별수준모델에 도입함으로써 이러한 문제를 해결할 수 있는 새로운 추정방법을 제안하였다. 제안된 추정량은 모의실험 연구를 통하여 기존의 표준적인 추정량과 그 성능을 비교하였다. 또한 미국의 National Toxicology Program으로부터 얻어진 정량적 대량고속 스크리닝(quantitative high throughput screening) 실제 자료를 사용하여 추정 방법들을 비교하였다.

• 대한인간공학회지
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• 제35권5호
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• pp.361-370
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• 2016

Objective:The aim of this study is to evaluate contributions of individual finger forces associated with various levels of submaximal voluntary contraction tasks. Background: Although many researches for individual finger force have been conducted, most of the studies mainly focus on the maximal voluntary contraction. However, Information concerning individual finger forces during submaximal voluntary contraction is also very important for developing biomechanical models and for designing hand tools, work equipment, hand prostheses and robotic hands. Due to these reasons, studies on the contribution of individual finger force in submaximal grip force exertions should be fully considered. Method: A total of 60 healthy adults without any musculoskeletal disorders in the upper arms participated in this study. The young group (mean: 23.7 yrs) consisted of 30 healthy adults (15 males and 15 females), and the elderly group (mean: 75.2 yrs) was also composed of 30 participants (15 males and 15 females). A multi-Finger Force Measurement (MFFM) System developed by Kim and Kong (2008) was applied in order to measure total grip strength and individual finger forces. The participants were asked to exert a grip force attempting to minimize the difference between the target force and their exerted force for eight different target forces (5, 15, 25, 35, 45, 55, 65, and 75% MVCs). These target forces based on the maximum voluntary contraction, which were obtained from each participant, were randomly assigned in this study. Results: The contributions of middle and ring fingers to the total grip force represented an increasing trend as the target force level increased. On the other hand, the contributions of index and little fingers showed a decreasing trend as the target force level increased. In particular, Index finger exerted the largest contribution to the total grip force, followed by middle, ring and little fingers in the case of the smallest target force level (5% MVC), whereas middle finger showed the largest contribution, followed by ring, index and little fingers at the largest target force levels (65 and 75% MVCs). Conclusion: Each individual finger showed a different contribution pattern to the grip force exertion. As the target force level increase from 5 to 75% MVC, the contributions of middle and ring fingers showed an increasing trend, whereas the contributions of index and little fingers represented a decreasing trend in this study. Application: The results of this study can be useful information when designing robotic hands, hand tools and work equipment. Such information would be also useful when abnormal hand functions are evaluated.

• 지능정보연구
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• 제18권4호
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• pp.79-95
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• 2012

금융기관들에서 개발한 신용 대출 상품이 증가함에 따라 사기 거래의 수 또한 급속히 증가하고 있다. 따라서, 재정적 위험을 성공적으로 관리하기 위해 금융기관들은 대출 승인 심사를 강화하고 신용 대출 사기를 사전에 탐지할 수 있는 능력을 증대시켜 나가야 한다. 신용 대출 사기를 탐지하기 위한 분류 모델을 구축하는 과정에서 분류 결과에 따른 유틸리티(즉, 정분류에 따른 이익과 오분류에 따른 비용)는 분류의 정확도보다 더 중요하다. 본 연구는 개인별 유틸리티에 기반하여 신용 대출 사기를 탐지하기 위한 분류 모델을 구축하는 것을 목적으로 하였다. 다양한 실험을 통해, 본 연구에서 제시한 모델이 기회 유틸리티와 현금 흐름의 두 관점 모두에서 개인별 유틸리티에 기반하지 않은 모델보다 더 높은 유틸리티를 제공하며, 평균 유틸리티에 기반한 모델보다 더 정확한 유틸리티를 제공한다는 것을 보였다. 본 연구는 기회 유틸리티와 현금 흐름의 두 관점에서 얻어진 실험 결과를 다양한 측면에서 살펴보았다.

• 한국산학기술학회논문지
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• 제17권2호
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• pp.351-360
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• 2016

본 연구는 서울시를 대상으로 개인의 행복수준에 영향을 미칠 것으로 예상되는 도시환경 특성요소를 추출하고 실제 주민들의 행복수준에 영향을 미치는 요인을 실증적으로 분석함으로써 보다 행복한 도시환경을 조성하기 위한 도시정책과 도시계획 방향을 제시하는데 목적이 있다. 개인의 행복수준에 영향을 미치는 도시환경 요소를 구성하기 위해 도시환경 특성(물리적 환경, 자연적 환경, 사회적 환경) 변수와 개인 특성(개인의 사회 경제적 특성) 변수를 구성하여 분석하였다. 본 연구의 주요 분석결과는 다음과 같다. 첫째, 도시의 물리적 환경이 개인의 행복수준에 미치는 영향을 분석한 결과 인구밀도가 낮고 보행환경만족도가 높을수록 개인의 행복수준이 높아지는 것으로 나타났다. 둘째, 도시의 자연적 환경이 개인의 행복수준에 미치는 영향을 분석한 결과 1인당 공원면적이 넓고 녹지만족도가 높을수록 개인의 행복수준이 높아지는 것으로 나타났다. 셋째, 도시의 사회적 환경이 개인의 행복수준에 미치는 영향을 분석한 결과, 사회적 신뢰가 행복수준에 영향을 미치는 것으로 나타났다.

• 보건행정학회지
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• 제23권3호
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• pp.233-243
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• 2013

Background: This study was conducted to evaluate the individual and community level factors which were influencing the severe injury patients' death and transfer at discharge. Methods: Analysis data is based on Korean National Hospital Discharge In-depth Survey Data released by the Korea Center for Disease Control and Prevention from 2006 to 2008. Study subjects was 11,026 inpatients with of severe injury. For multi-level analysis, socio-demographic characteristics, injury related characteristics, hospitalization related characteristics were used as individual level factors, and socio-environmental characteristics and health care resource characteristics were used as community level factors. Results: As to community level factors affecting mortality of severe injury, the possibility of death was also high in cases of less numbers of surgeons per a population of 100,000 and more number of operation beds. As to community level factors affecting transfer of severe injury, vulnerable areas with higher social deprivation index and low population density had higher possibility of transfer. Conclusion: Both individual level factors and community level factors affected clinical outcomes of treatment for severe injury. In particular, since there happened higher death and transfer of severe injury in socioeconomic and medical vulnerable areas, special efforts for establishing preventive policy and care system for injury in national and area level should be directed toward such areas.

• 대한보건연구
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• 제44권4호
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• pp.83-85
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• 2018

As the main aim of infectious disease epidemiology is to prevent a pathogen transmission, traditional epidemiological studies have focused on the evaluation of individual-level risk factors. But group-level factors as well as individual-level are important in understanding and controlling transmission of infectious diseases, especially sex-transmitted infectious diseases. Multi-level analysis (MLA) is known as a powerful analytical tool for investigating both levels simultaneously. While new cases of HIV/AIDS in Korea are increasing annually, it is urgently needed to establish research system for MLA led by Korea Centers for Disease Control & Prevention.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.370-377
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• 2023

Previous research has demonstrated that happy moods are known to promote feeling-based processing, whereas sad moods promote reason-based processing. The current research investigates a boundary condition for the effects of a happy mood on feeling-based decision making. This research proposes that the level of control (low vs. high) one exercises in a happy situation can promote a greater reliance on feelings (vs. reasons) in making judgments and decisions. Specifically, we hypothesize that (1) a happy individual in a situation where control level is low (vs. high) will be more likely to choose a cognitively (vs. affectively) superior option (hypothesis 1), and (2) a happy individual in a situation where control level is low (vs. high) will exert reason- (vs. feeling-) based processing (hypothesis 2). Consistent with the hypothesis 1, the results of two experiments show that happy individuals are more likely to choose cognitively versus affectively superior options in a situation where control level is low (vs. high). Moreover, the mediation analysis confirms that happy individuals are more likely to rely on cognitive, reason-based decision making when their control level is low, which supports the hypothesis 2.

• 한국가정과교육학회지
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• 제8권1호
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• pp.51-57
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• 1996

The purpose of this study were to examine the difference of the effect of CAI and students’attitude to Home Economics Class through CAI. 120 girl students of the first year were chosen at B middle school in Daegu. Among them each 30 students were classified into 4 groups； High Intelligence group/Individual learning pattern, High Intelligence group/Small group learning pattern, Low Intelligence group/Individual learning pattern, Low Intelligence group/Small group learning pattern. The task of learning was “management of washing”Unit of the second grade. The data were processed with Cronbach’s ${\alpha}$, t-test, ANOVA by SPSS/PC(sup)+. The research findings are as follows： 1. In the verification of CAI Learning effect according to student group pattern, there is no difference between Individual learning pattern and Small group learning pattern in Achivement and Retention of learning. 2. In the verification of CAI Learning effect according to student intelligence level, there is no difference between High Intelligence group and Low Intelligence group in Achivement and Retention of learning. 3. The result of students’attitude to Home Economics Class verificated is an follows. (1) Individual learning pattern is more attensive than Small group learning pattern, but there is no difference in Intelligence level. (2) Low Intelligence group is more positive than High Intelligence group, and Small group learning pattern is more positive than Individual learning pattern in a view of Home Economics Class after using CAI.

• The Journal of Asian Finance, Economics and Business
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• 제8권8호
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• pp.525-532
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• 2021

The study investigates the mediating effect of Korean firms' corporate social responsibility (CSR) in the relationship between Korean executives' religiosity, their individual social responsibility (ISR), and corporate financial performance (CFP). As executives lead the firms' strategies and policies, their religiosity or ISR may have a significant influence in attaining the firm's CSR and influencing CFP. The upper echelon theory, agency theory, and stakeholder theory are used to explain the link between individual-level drivers of CSR, a firm's CSR, and CFP. The upper echelon theory, agency theory, and stakeholder theory are integrated into the conceptual model, which explains the relationships between proposed constructs in this study. This study employs survey data of 421 Korean companies. The confirmatory factor analysis (CFA) technique was used to test the proposed hypotheses. The main result shows that Korean executives' religiosity and their ISR positively influence CFP when mediated by CSR. The findings of this study suggest that Korean executives' personal values such as their religiosity and ISR can impact the firm's CSR activities or financial performance. Overall, this paper responds to the recent calls in the CSR literature to examine the individual-level drivers from non-western contexts by shedding more light on the Korean context.

• 지역사회간호학회지
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• 제27권4호
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• pp.337-345
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• 2016

Purpose: This study aims at identifying individual- and school-level factors associated with unintentional injuries to Korean adolescents at school by applying multilevel modeling. Methods: From the database of the eleventh Korea Youth Risk Behavior Web-based Survey (KYRBS), the researchers selected 68,043 adolescents from the $7^{th}$ to the $12^{th}$ grades. Data were analyzed using ${\chi}^2$ test for prevalence and multilevel modeling for related factors of unintentional injuries at school. Results: About 22.9 percent of the adolescents had treatment experiences for unintentional injuries at school in the past 12 months. At the individual level, the significant factors associated with unintentional injuries at school included gender, grade, academic achievement, current smoking, alcohol consumption, frequency of high caffeine intake, depression, and relief of fatigue after sleep. At the group level, the significant factors included number of physical education per week and safety education. Conclusion: School based injury prevention programs should be sensitive to both individual- and school-level factors associated with unintentional injury at school among Korean adolescents.