• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (A)
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• pp.4-6
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• 2006

Tree-dependent component analysis (TCA) is a generalization of independent component analysis (ICA), the goal of which is to model the multivariate data by a linear transformation of latent variables, while latent variables fit by a tree-structured graphical model. In contrast to ICA, TCA allows dependent structure of latent variables and also consider non-spanning trees (forests). In this paper, we present a TCA-based method of clustering gene expression data. Empirical study with yeast cell cycle-related data, yeast metaboiic shift data, and yeast sporulation data, shows that TCA is more suitable for gene clustering, compared to principal component analysis (PCA) as well as ICA.

• 한국컴퓨터정보학회논문지
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• 제25권10호
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• pp.193-201
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• 2020

본 연구는 팀 기반 학습 모델을 인문사회계열 학생들의 수업에 적용하여 문제해결능력의 효과성을 평가하고 하위요인들 간의 관계에 대한 구조모형분석을 실시하는 것이다. 팀 기반 학습은 인문사회계열의 2학년과 3학년 각각 30명을 6개의 팀으로 구성하여 6차례 실시하였다. 대상학생들의 문제해결능력 점수는 팀 기반 학습 후의 문제해결능력 점수가 상당히 높게 나타났으며 통계적으로 유의미하게 나타났다. 문제해결능력 하위요인인 잠재변수들과의 정규성에 문제가 없었고, 잠재변수들에 대한 관측변수들의 확인적 요인분석에서 요인부하량 값이 .001수준에서 통계적으로 유의미하여 타당한 모형이었다. 연구모형의 적합도 검증에서도 좋은 수준의 적합도를 보여주었다. 결과적으로 원인분석, 문제명료화, 계획실행, 수행평가, 대안개발의 잠재변수들 간에는 서로 간접 또는 직접적으로 영향을 미치고 있는 것으로 분석되었다.

• Industrial Engineering and Management Systems
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• 제11권4호
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• pp.371-384
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• 2012

This study proposes a multi-level data analysis approach to identify both superficial and latent relationships among variables in the data set obtained from a vocational rehabilitation (VR) services program of people with significant disabilities. At the first layer, data mining and statistical predictive models are used to extract the superficial relationships between dependent and independent variables. To supplement the findings and relationships from the analysis at the first layer, association rule mining algorithms at the second layer are employed to extract additional sets of interesting associative relationships among variables. Finally, nonlinear nonparametric canonical correlation analysis (NLCCA) along with clustering algorithm is employed to identify latent nonlinear relationships. Experimental outputs validate the usefulness of the proposed approach. In particular, the identified latent relationship indicates that disability types (i.e., physical and mental) and severity (i.e., severe, most severe, not severe) have a significant impact on the levels of self-esteem and self-confidence of people with disabilities. The identified superficial and latent relationships can be used to train education program designers and policy developers to maximize the outcomes of VR training programs.

• 한국조사연구학회지:조사연구
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• 제12권2호
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• pp.113-144
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• 2011

본 연구의 목적은 청년 취업자의 직무만족도와 이직의사의 다양한 변화형태를 추정하여 잠재계층을 분류하고, 두 변수에 영향을 미치는 직무적합도(전공적합도, 교육수준적합도, 기술수준적합도)와의 효과를 밝히는 것이다. 이를 위하여 청년패널 2001의 만 15∼29세 청년 취업자를 대상으로 한 2001년부터 2006년까지의 종단자료를 이용하였다. 직무만족도와 이직의사의 잠재계층을 동시에 도출하기 위해 준모수적 집단중심 접근 방법의 확장모형인 이중 변화형태 모형(dual trajectory model)을 적용하였다. 분석 결과, 직무만족도 변화에 따른 잠재계층은 4개로 분류되었고, 변화형태에 따라 증가집단, 감소집단, 중간수준집단, 고수준집단으로 명명하였다. 이직의사 변화에 따른 잠재 계층은 3개로 분류되었고, 변화형태에 따라 저수준집단, 유지집단, 급감소집단으로 명명하였다. 직무만족도와 이직의사에 시간의존적 변수인 전공적합도, 교육수준적합도, 기술수준 적합도의 영향력을 검증한 결과, 직무만족도가 낮거나 이직의사가 높은 집단에는 교육수준 적합도 또는 기술수준적합도의 영향력이 유의하게 나타났다. 본 연구는 오랜 기간 직무만족도가 낮거나 이직의사를 지속적으로 가지고 있는 청년 취업자들을 위한 대책을 마련하는데 도움을 줄 것이다. 또한 잠재계층 모형을 확장시켜 두 가지 변수의 잠재계층을 동시에 도출하고, 그 잠재계층을 결정짓는 데 미치는 시간의존적 독립변수의 효과를 검증하는 종단연구 방법을 적용했다는 점에서 연구방법론적 측면에서 의의가 있다.

• 한국문헌정보학회지
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• 제56권4호
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• pp.455-472
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• 2022

본 연구의 목적은 도서관 이용행태를 나타내는 지표 중의 하나인 대출권수에 영향을 미치는 요인을 분석하는 것이다. 분석을 위해 국가도서관통계시스템에 등록된 2015년부터 2019년까지 공공도서관 데이터를 이용하였다. 각 도서관별 변화의 형태를 이용하여 전체적인 도서관 변화를 추정하는 잠재성장모형을 적용한 분석결과는 다음과 같다. 첫째, 전반적으로 대출권수가 줄어드는 경향을 보였다. 둘째, 대출권수 감소에 가장 큰 영향을 미치는 변수는 자료구입비로 나타났다. 따라서 본 연구는 도서관의 이용과 관련하여 일상적인 도서관 업무의 범위 내에서 대출권수 감소를 줄이기 위한 방법으로 자료구입비를 확대할 것을 제안한다.

• 한국안전학회지
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• 제36권3호
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• pp.60-65
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• 2021

Human error is often in part in the cause of accidents and the result of various factors in an organization. Accidents should be investigated to elucidate all causes. Therefore, to reduce accidents, it is necessary to identify which factors affect human error within the organization. In this study, five groups of influencing factors on human error were selected using previousresearch, and operational definitions were made based on them. In addition, a questionnaire for measuring latent variables by operational definition was developed as an observation variable, and responses were received from employees of chemical companies in Ulsan. Based on SEM (structural equation modeling) analysis, 1) confirmatory factor analysis of variables in the human error model, 2) reliability and validity of latent variables, 3) correlations among latent variables, 4) influencing coefficients among influence factors, and 5) the verification results of the paths that these influencing factors have on human error are introduced in this study.

• 한국도로학회논문집
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• 제14권6호
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• pp.121-129
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• 2012

PURPOSES : Traffic accidents at intersections have been increased annually so that it is required to examine the causations to reduce the accidents. However, the current existing accident models were developed mainly with non-linear regression models such as Poisson methods. These non-linear regression methods lack to reveal complicated causations for traffic accidents, though they are right choices to study randomness and non-linearity of accidents. Therefore, to reveal the complicated causations of traffic accidents, this study used structural equation methods(SEM). METHODS : SEM used in this study is a statistical technique for estimating causal relations using a combination of statistical data and qualitative causal assumptions. SEM allow exploratory modeling, meaning they are suited to theory development. The method is tested against the obtained measurement data to determine how well the model fits the data. Among the strengths of SEM is the ability to construct latent variables: variables which are not measured directly, but are estimated in the model from several measured variables. This allows the modeler to explicitly capture the unreliability of measurement in the model, which allows the structural relations between latent variables to be accurately estimated. RESULTS : The study results showed that causal factors could be grouped into 3. Factor 1 includes traffic variables, and Factor 2 contains turning traffic variables. Factor 3 consists of other road element variables such as speed limits or signal cycles. CONCLUSIONS : Non-linear regression models can be used to develop accident predictions models. However, they lack to estimate causal factors, because they select only few significant variables to raise the accuracy of the model performance. Compared to the regressions, SEM has merits to estimate causal factors affecting accidents, because it allows the structural relations between latent variables. Therefore, this study used SEM to estimate causal factors affecting accident at urban signalized intersections.

• 가정과삶의질연구
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• 제33권1호
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• pp.1-17
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• 2015

This study investigated how variables of internalizing and externalizing problematic behaviors change according to gender and as time passes by and how the variables influence adolescent problematic behaviors. The variables selected for the analysis are personal variables, parent variables, peer and school variables, and community variables. longitudinal data collected for 4 years from the Korea Youth Panel Survey(KYPS) were utilized for the analysis. Data were collected initially from 2,707 fifth grade elementary students in 2005 and they were traced until 2008. The final respondents were 2,448 students. The findings are as follows. Frist, the statistical significance was found in changes of problematic behavioral variables in terms of the gender difference. Second, variables, such as self-esteem and self-control are negatively correlated to the problematic behaviors and stress level is strongly positively correlated to the behaviors. Third, the study pressure and peer attachment level are correlated to the initial value of internalizing problematic behaviors. In conclusion, given that more statistical significances were found at initial values than the change rates among variables, early intervention is important in addressing adolescent problematic behaviors.

• 응용통계연구
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• 제27권7호
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• pp.1077-1095
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• 2014

관찰연구를 이용하여 인과관계를 추론할 경우 무작위 통제시험과는 달리 교란변수로 인한 편향을 제어하기 위한 통계적 전략이 필요하다. 최근에는 성향점수(propensity score) 를 이용한 짝짓기나 원인변수의 역확률을 가중치로 사용하는 주변구조모형이 제안되어 사용되고 있다. 이러한 인과관계 추론은 처치(treatment)가 명확히 주어진 경우에 교란변수를 통제하고 그 처치가 결과에 미치는 영향을 평가하는 방법에 초점이 맞추어져 있다. 하지만 기존의 방법의 경우 원인변수인 처치가 직접관측이 가능한 범주형 변수이고 결과변수 또한 직접관측이 가능한 변수인 경우에만 사용할 수 있는 한계를 갖고 있다. 본 연구에서는 원인변수인 처치와 결과변수의 결괏값의 직접적인 관측이 어려운 경우, 측정오차를 고려한 잠재범주모형(latent class analysis)의 변수로 모형화 함으로써 잠재범주 간의 원인적 영향력을 추정하는 방법을 제시하고자 한다. 그리고 미국의 The National Longitudinal Study of Adolescent Health 자료를 이용하여, 약물사용의 잠재범주에 대한 청소년기의 비행(delinquency)이라는 잠재범주의 원인적 영향력을 추정하였다.

• International journal of advanced smart convergence
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• 제10권4호
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• pp.124-133
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• 2021

The purpose of this study is to analyze the types of latent profiles of high school students' fire safety awareness and to identify the characteristics of related variables. For this purpose, a survey was conducted from March 22 to May 25, 2021 for 1054 high school students (male; 569, female; 485) in 3 cities, in Jeollabuk-do. The latent profile was analyzed using a scale consisting of 4 sub-factors: 'fire prevention', 'fire preparedness', 'indirect fire response', and 'direct fire response'. It was checked whether there were differences according to the inter-individual differences of the latent group. As a result of the analysis, fire safety awareness of high school students was classified into three latent profiles. The three groups were named 'High Perception Type', 'Moderate Perception Type', and 'Low Perception Type' according to their types. In fire safety awareness, there is a significant difference in the individual differences according to the gender and academic achievement of the latent profile. These results are meaningful as the first study to analyze the latent profile of high school students' fire safety awareness, and it is also meaningful to provide a useful basis for the contents and methods of customized fire safety education by identifying the tendencies of spontaneous groups and their fire safety awareness.