• The Korean Journal of Applied Statistics
• /
• v.28 no.1
• /
• pp.61-74
• /
• 2015

Structural equation modeling (SEM) is a widely used in social sciences such as education, business administration, and psychology. In SEM, the latent variable score is the estimate of the latent variable which cannot be observed directly. This study uses stagewise structural equation modeling(stagewise SEM; SSEM) by partitioning the whole model into several stages. The traditional estimation method minimizes the discrepancy function using the variance-covariance of all observed variables. This method can lead to inappropriate situations where exogenous latent variables may be affected by endogenous latent variables. The SSEM approach can avoid such situations and reduce the complexity of the whole SEM in estimating parameters.

• The Korean Journal of Applied Statistics
• /
• v.30 no.5
• /
• pp.615-632
• /
• 2017

Unlike randomized trial, statistical strategies for inferring the unbiased causal relationship are required in the observational studies. The matching with the propensity score is one of the most popular methods to control the confounders in order to evaluate the effect of the treatment on the outcome variable. Recently, new methods for the causal inference in latent class analysis (LCA) have been proposed to estimate the average causal effect (ACE) of the treatment on the latent discrete variable. They have focused on the application study for the real dataset to estimate the ACE in LCA. In practice, however, the true values of the ACE are not known, and it is difficult to evaluate the performance of the estimated the ACE. In this study, we propose a method to generate a synthetic data using the propensity score in the framework of LCA, where treatment and outcome variables are latent. We then propose a new method for estimating the ACE in LCA and evaluate its performance via simulation studies. Furthermore we present an empirical analysis based on data form the 'National Longitudinal Study of Adolescents Health,' where puberty as a latent treatment and substance use as a latent outcome variable.

• The Korean Journal of Applied Statistics
• /
• v.27 no.7
• /
• pp.1077-1095
• /
• 2014

Unlike randomized trial, statistical strategies for inferring the unbiased causal relationship are required in the observational studies. Recently, new methods for the causal inference in the observational studies have been proposed such as the matching with the propensity score or the inverse probability treatment weighting. They have focused on how to control the confounders and how to evaluate the effect of the treatment on the result variable. However, these conventional methods are valid only when the treatment variable is categorical and both of the treatment and the result variables are directly observable. Research on the causal inference can be challenging in part because it may not be possible to directly observe the treatment and/or the result variable. To address this difficulty, we propose a method for estimating the average causal effect when both of the treatment and the result variables are latent. The latent class analysis has been applied to calculate the propensity score for the latent treatment variable in order to estimate the causal effect on the latent result variable. In this work, we investigate the causal effect of adolescents delinquency on their substance use using data from the 'National Longitudinal Study of Adolescent Health'.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.10
• /
• pp.193-201
• /
• 2020

This study is to evaluate the effectiveness of problem-solving ability by applying a team-based learning model to the classes of humanities and social science students, and to conduct a structural model analysis on the relationship between sub-factors. Team-based learning was conducted six times in six teams with 30 students in the second and third grades of the humanities and social sciences. The problem solving ability score of the target students was significantly higher after team-based learning and was statistically significant. There was no problem in normality with the latent variables, which are the sub-factors of problem solving ability, and the factor load value was statistically significant at the .001 level in the confirmatory factor analysis of the observed variables for the latent variables, which was a valid model. A good level of fitness was also shown in the verification of the fitness of the research model. As a result, it was analyzed that latent variables of cause analysis, problem clarification, planning execution, performance evaluation, and alternative development had an indirect or direct influence on each other.

• Proceedings of the KAIS Fall Conference
• /
• 2010.05b
• /
• pp.1205-1208
• /
• 2010

본 연구는 초등학교 5, 6학년 학생의 인터넷 중독과 학교생활 적응과의 관계를 파악하여 인터넷 사용에 대한 교육적 지도방안과 인터넷 중독 예방프로그램 개발의 기초 자료를 제공하고자 시도되었다. 자료는 2009년 7월 1일에서 7월 24일까지 제주특별자치도에 위치한 초등학교 6개교(동지역 4개교, 읍지역 2개교)를 무작위 추출하여 5, 6학년 학생 총 1195명을 대상으로 조사하였다. 자료 분석은 SPSSWIN(12.0 한글판) 프로그램을 이용하여 카이제곱검정, t-검정, 일원배치 분산분석, 상관분석, 다중회귀분석의 통계적 방법을 이용하였다. 본 연구의 주요 결과는 첫째, 대상자의 인터넷 중독 정도는 고위험군 55명(5.5%), 잠재적위험군 49명 (4.9%), 정상군 900명(89.6%)으로 나타났으며, 둘째, 대상자의 일반적 특성에 따른 인터넷 중독 정도를 분석한 결과 성별, 형제자매 유무, 학교성적에 따라 유의한 차이가 있었다. 셋째, 대상자의 컴퓨터 사용 특성에 따른 인터넷 중독 정도는 최초 인터넷 이용 시기, 인터넷 이용용도, 하루 인터넷 사용 시간, 부모컴퓨터 사용 여부에 따라 유의한 차이가 있었으며, 넷째, 인터넷 중독과 학교생활 적응과의 관계를 분석한 결과 학교생활 부적응인 경우는 '고위험군' 32명(58.2%), '잠재적위험군' 24명(50.0%), '정상군' 257명 (28.7%)으로 고위험군과 잠재적위험군이 정상군보다 학교생활 적응 정도가 낮은 것으로 조사되었다(p<0.01). 다섯째, 인터넷 중독에 유의한 영향을 주는 변수는 학교생활 적응 정도, 성별, 하루 인터넷 사용시간, 인터넷 이용용도, 인터넷 이용 상황, 어머니 직장 유무, 거주 지역, 부모 컴퓨터 사용여부, 최초 인터넷 이용시기이었다. 학교생활 적응 정도가 낮을 때, 남학생, 하루 인터넷 사용시간이 3시간 이상, 인터넷 이용 용도가 '게임', '스트레스가 쌓였을 때' 인터넷을 이용하는 경우, 어머니 직장이 있는 경우, 거주 지역이 동지역, 부모님이 컴퓨터를 사용할 줄 모르는 경우, 최초 인터넷 이용 시기가 취학 전인 경우가 인터넷 중독 점수가 높은 것으로 나타났다. 여섯째, 학교생활 적응에 유의한 영향을 주는 변수는 인터넷 중독 점수, 학교성적, 가정경제수준, 거주지역, 인터넷 이용용도, 학년이었다. 인터넷 중독 점수가 낮을수록, 학교성적이 높을수록, 가정경제수준이 잘 살수록, 거주지역이 동지역, 인터넷 이용용도가 '정보검색, 홈페이지관리/메신저', 5학년인 경우에 학교생활 적응을 더 잘하고 있는 것으로 나타났다. 이상의 결과를 종합해 보면, 학교생활 적응 정도가 낮을수록 인터넷 중독 점수가 높게 나타나고 있고, 인터넷 중독 경향이 높을수록 학교생활 적응 수준이 낮게 나타나고 있음을 알 수 있다. 아동들은 하루중 대부분의 시간을 학교에서 생활하고 있기 때문에 학교생활 적응은 아동들이 건전한 성인으로 성장하는데 중요한 요인이 된다. 또한, 인터넷사용률 증가와 최초 인터넷 이용 연령층이 점점 낮아지고 있음에 따라 인터넷 중독률이 자연스럽게 점점 높아질 것으로 예측되어진다. 따라서, 가정과 학교가 연계하여 아동들의 인터넷 사용에 대한 지속적인 관심과 지도가 필요하며, 인터넷 중독경향이 높은 아동들이 학교생활 적응을 잘할 수 있도록 인터넷 중독 치료 및 예방교육 프로그램 운영이 필요하다 하겠다.

• Korean Journal of School Psychology
• /
• v.18 no.3
• /
• pp.291-316
• /
• 2021

This study was conducted to identify how special education teachers perceive their school's organizational climate through latent profile analysis performed using Mplus, and determine whether there was a difference in the average teacher burnout rate between perception groups using three-step approaches. The participants were 312 special education teachers. The perception groups were identified as 'closed', 'laissez-faire', 'average', 'controlled', and 'autonomous.' The groups had different teacher burnout rates. The closed group had the highest rate, while the autonomous group had the lowest. This paper discusses the implications of these results for special education teacher burnout and school organizational climate, and suggests ideas for future studies.

• Journal of Animal Science and Technology
• /
• v.46 no.4
• /
• pp.509-516
• /
• 2004

This study is to investigate the amount of biased estimates for heritability and genetic correlation according to data structure on marbling scores in Korean cattle. Breeding population with 5 generations were simulated by way of selection for carcass weight, Longissimus muscle area and latent values of marbling scores and random mating. Latent variables of marbling scores were categorized into five by the thresholds of 0, I, 2, and 3 SD(DSI) or seven by the thresholds of -2, -1, 0,1I, 2, and 3 SD(DS2). Variance components and genetic pararneters(Heritabilities and Genetic correlations) were estimated by restricted maximum likelihood on multivariate linear mixed animal models and by Gibbs sampling algorithms on multivariate threshold mixed animal models in DS1 and DS2. Simulation was performed for 10 replicates and averages and empirical standard deviation were calculated. Using REML, heritabilitis of marbling score were under-estimated as 0.315 and 0.462 on DS1 and DS2, respectively, with comparison of the pararneter(0.500). Otherwise, using Gibbs sampling in the multivariate threshold animal models, these estimates did not significantly differ to the parameter. Residual correlations of marbling score to other traits were reduced with comparing the parameters when using REML algorithm with assuming linear and normal distribution. This would be due to loss of information and therefore, reduced variation on marbling score. As concluding, genetic variation of marbling would be well defined if liability concepts were adopted on marbling score and implemented threshold mixed model on genetic parameter estimation in Korean cattle.

• Journal of the Korean Society for Railway
• /
• v.17 no.5
• /
• pp.381-389
• /
• 2014

This research focuses on the current trend of 'Sharing Transportation' to clarify the regional factors having a decisive effect on the use of Car Sharing. To accomplish this, the current research is built a Database of the regional characteristics of Car Sharing spots based on railway stations in Seoul and performed an analysis of the primary regional factors affecting Car Sharing usage. As a result, we found conclusive factors affecting the use of Car Sharing. This research can be utilized for establishing strategies and effective measures to support the use of Car Sharing and sustainable development with respect to issues of motorization.

• KIPS Transactions on Software and Data Engineering
• /
• v.11 no.6
• /
• pp.237-244
• /
• 2022

In this paper, we present VAE-based recommendation using online behavior log and purchase history to overcome data sparsity and cold start. To generate a variable for customers' purchase history, embedding and dimensionality reduction are applied to the customers' purchase history. Also, Variational Autoencoders are applied to online behavior and purchase history. A total number of 12 variables are used, and nDCG is chosen for performance evaluation. Our experimental results showed that the proposed VAE-based recommendation outperforms SVD-based recommendation. Also, the generated purchase history variable improves the recommendation performance.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.10
• /
• pp.197-205
• /
• 2023

This study is to apply the Havruta teaching-learning method to college students' major classes and analyze the relationship between the effectiveness evaluation of communication skills and sub-factors using a structural equation model. As a result of the study, the communication ability score was different before and after Havruta teaching-learning, and it was found that after Havruta teaching-learning was higher than before Havruta teaching-learning. The path effect was found to be significant in all of the total, direct, and indirect effects among latent variables, except for the relationship between interpretation ability, role-playing ability, and goal-setting ability in the direct effect. In this study, it was found that the Havruta teaching-learning method not only improves creativity and thinking ability, but also improves self-directed learning ability. In addition, it was reconfirmed that it is a teaching-learning method that can develop social skills and communication skills as well as problem-solving skills while experiencing opinions different from one's own. As a result, research on a thorough student-centered teaching-learning method suitable for the Homo Machina era must be continued and its application in the educational field must be implemented.