• Journal of Korea Planning Association
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• v.54 no.5
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• pp.129-138
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• 2019

This study aims to empirically examine the relationship between building energy consumption and building and local factors in Seoul. Building energy issue is an important topic for low carbon and eco-friendly city development. Building physical, socio-economic and environmental factors effect to increasing or decreasing energy consumption. However, there are different characteristic in each area, and this kind of variable has a hierarchical structure. The multi-level model was used to consider the hierarchical structure of the variables. In this study, a multi-level model was applied to confirm the difference between areas. Spatial area is Seoul, Korea and the temporal scope is August, summer season. As the result, in Model 1 (Null Model), ICC is 0.817. This shows that the energy consumption differs by 8.174% due to factors at the Dong level. Model 2 (Random Intercept Model) suggests that building's physical factors and Average age, Household size and Land price in Dong level have significant effects on Building energy consumption. In Model 3 (Random Coefficient Model), random effect variables have intercepts and slopes to vary across groups. This study provides a perspective for policy makers that the building energy reduction policies to be applied for buildings should be differently applied on area. Furthermore, not only physical factors but also socio-economic and environmental factors are important when making energy reduction policy.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.394-406
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• 2015

In this work, an efficient aircraft landing simulation strategy is proposed to develop an efficient and reliable hard-landing monitoring procedure. Landing stage is the most dangerous moment during operation cycle of aircraft and it may cause structural damage when hard-landing occurs. Therefore, the occurrence of hard-landing should be reported accurately to guarantee the structural integrity of aircraft. In order to accurately determine whether hard-landing occurs or not from given landing conditions, full nonlinear structural dynamic simulation can be performed, but this approach is highly time-consuming. Thus, a more efficient approach for aircraft landing simulation which uses a hierarchical aircraft landing model and an extended inertia relief technique is proposed. The proposed aircraft landing model is composed of a multi-body dynamics model equipped with landing gear and tire models to extract the impact force and inertia force at touch-down and a linear dynamic structural model with an extended inertia relief method to analyze the structural response subject to the prescribed rigid body motion and the forces extracted from the multi-body dynamics model. The numerical examples show the efficiency and practical advantages of the proposed landing model as an essential component of aircraft hard-landing monitoring procedure.

• (The)Korea Educational Review
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• v.23 no.2
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• pp.5-30
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• 2017

In this study, we analyzed the longitudinal effect of participation in an overseas exchange student program on foreign language competence, intercultural competence, and personal development. Data were collected over three time points from the pre-, post-, and post-post tests with Korean college students who participated in an overseas exchange program. Hierarchical linear model was conducted to examine whether the change of participation effects exists over time and which predictors affected outcomes. The results of unconditional growth model showed that foreign language competence, cultural competence, and personal development showed statistically significant differences in their initial status prior to departure to participate in an overseas program as well as their growth rate. The results of conditional growth model showed that parents' level of education and overseas experiences before college affected the initial status of foreign language competence, and gender and overseas experience before college affected those of cultural competence as well as personal development. In case of growth rate, overseas experience before college and destination country/region affected foreign language competence, and interactions between Korean participating students and local students affected cultural competence. For personal development, only overseas experiences before college affected its growth rate. Lastly, relevant discussion and implications were provided.

• Communications for Statistical Applications and Methods
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• v.21 no.1
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• pp.45-60
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• 2014

We introduce a MCMC sampling for a generalized linear normal random effects model with the ordered probit link function based on latent variables from suitable truncated normal distribution. Such models have proven useful in practice and we have observed numerically reasonable results in the estimation of fixed effects when the random effect term is provided. Applications that utilize Korean Welfare Panel Study data can be difficult to model; subsequently, we find that an ordered probit model with the random effects leads to an improved analyses with more accurate and precise inferences.

• Korean Journal of Childcare and Education
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• v.11 no.2
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• pp.59-85
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• 2015

The purpose of this study was to investigate the effects of child care teachers' emotional supports in individual classrooms on children's social skills, including self-control, assertion, cooperation, and responsibility that were related to their character development. Data were collected in a purposive sample involving 32 teachers working with 646 children at age five and 555 parents of the children. Hierarchical Linear Modeling (HLM) was used to analyze a two-level model. The results showed that there were significant differences among classes with data reported by teachers but characteristics such as teachers' education and work experiences, child-teacher ratio, and type of child care centers as well as teacher's emotional supports did not explain the differences. Children's age and gender, which were predictors at the individual level, significantly explained their level of social skills reported by parents as well as teachers. The findings implied that other predictors influencing differences among classes should be explored in future studies.

• Journal of KIISE:Software and Applications
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• v.31 no.1
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• pp.1-7
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• 2004

For the handwritten digit recognition, this paper Proposes a hierarchical Gator features extraction method and a Bayesian network for them. Proposed Gator features are able to represent hierarchically different level information and Bayesian network is constructed to represent hierarchically structured dependencies among these Gator features. In order to extract such features, we define Gabor filters level by level and choose optimal Gabor filters by using Fisher's Linear Discriminant measure. Hierarchical Gator features are extracted by optimal Gabor filters and represent more localized information in the lower level. Proposed methods were successfully applied to handwritten digit recognition with well-known naive Bayesian classifier, k-nearest neighbor classifier. and backpropagation neural network and showed good performance.

• Journal of Information Processing Systems
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• v.1 no.1 s.1
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• pp.22-26
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• 2005

In this paper, we classified the objectionable texts into four rates according to their harmfulness and proposed the hierarchical text rating system for objectionable documents. Since the documents in the same category have similarities in used words, expressions and structure of the document, the text rating system, which uses a single classification model, has low accuracy. To solve this problem, we separate objectionable documents into several subsets by using their properties, and then classify the subsets hierarchically. The proposed system consists of three layers. In each layer, we select features using the chi-square statistics, and then the weight of the features, which is calculated by using the TF-IDF weighting scheme, is used as an input of the non-linear SVM classifier. By means of a hierarchical scheme using the different features and the different number of features in each layer, we can characterize the objectionability of documents more effectively and expect to improve the performance of the rating system. We compared the performance of the proposed system and performance of several text rating systems and experimental results show that the proposed system can archive an excellent classification performance.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.1013-1025
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• 2016

The purpose of this study was to analyze longitudinal effect of physical education activity (PEA) score on self-rated health evaluation change (SHEC). This study used hierarchical linear and nonlinear models to investigate of the SHEC during the transition into adolescence (from middle school 1st to high school 2nd grade). Using the Korea children and youth panel survey (KCYPA), data were collected over the course of five years (from 2010 and 2014). HLM 6.8 computer program was used to analyze the data. The result were as follows. First, boys' SHEC increased across the five years, and girls' SHEC decreased across the five years. Second, boys' the self-rated health was increased across the three years and decreased across the two years. Third, girls' the self-rated health was increased across the two years and decreased across the three years. Fourth, the PEA score of 1st grade of high school showed a significant positive association with the boys' SHEC. Fifth, the PEA score of 1st grade of middle school showed a significant negative association with the girls' SHEC.

• Journal of Digital Convergence
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• v.18 no.11
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• pp.1-11
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• 2020

Economic factors are important in improving life satisfaction of disabled people. In addition, the impact of job satisfaction on life satisfaction has been verified. However, according to Herzberg's motivation-hygiene theory, hygiene factors such as wages only lowers dissatisfaction and does not directly affect job satisfaction. This study raises questions about Herzberg's theory and seeks to confirm through empirical analysis. Based on data from the 2017 Employment Panel Survey for the Disabled, this study seeks to answer analyzes whether hygiene factors proposed by Herzberg affect the job satisfaction of disabled people or not. Furthermore, this study proposes what regional policies are needed to enhance job satisfaction for the disabled. An analysis of structural equation model showed that hygiene factors such as working environment, interpersonal relationship and personal life directly affect the disabled worker's job satisfaction. In addition, through hierarchical linear model analysis, it was confirmed that local governments ought to provide education supports to the disabled workers in order to improve their job satisfactions.

• Health Policy and Management
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• v.26 no.3
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• pp.155-171
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• 2016

Background: In this study, state-owned medical institutes, industrial accident hospitals, veteran hospitals, and private medical clinics including 16 university medical institutes in the Seoul metropolitan area were selected to examine the causality of ethical management, positive psychological capital, and organizational effectiveness. Methods: The study analyzed 1,056 valid questionnaires to which a total of 1,325 nurses, medical technicians, doctors, and administrative staff in 34 healthcare organizations answered over two months from June to August 2015. The study also utilized a 'structural equation model,' and a 'hierarchical linear model' to conduct the analysis. Results: It was first found that ethical leadership, ethical management systems, and organizational ethics values, which are the three factors of ethical management, had significant influence on organizational commitment, and behavior. These are the three factors of employee organizational effectiveness. Second, ethical management, ethical leadership, ethical management systems, and organizational ethics values had significant influence on positive psychological capital. Third, positive psychological capital had significant influence on organizational commitment, turnover intention, and organizational citizenship behavior. Positive psychological capital presented an indirect effect on the relationship between the ethical management and organizational effectiveness of employees. The effect of positive psychological capital consisting of self-efficacy, hope, resilience, and optimism was confirmed in the healthcare organizations. Fourth, in relations among ethical management variables, ethical leadership showed a significant impact on ethical management systems, which had significant impacts on organizational ethics values, which had significant impacts on ethical leadership.