• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.1
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• pp.109-116
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• 2001

The detection of corporate failures is a subject that has been particularly amenable to cross-sectional financial ratio analysis. In most of firms, however, the financial data are available over past years. Because of this, a model utilizing these longitudinal data could provide useful information on the prediction of bankruptcy. To correctly reflect the longitudinal and firm-specific data, the generalized linear model with assuming the first order AR(autoregressive) process is proposed. The method is motivated by the clinical research that several characteristics are measured repeatedly from individual over the time. The model is compared with several other predictive models to evaluate the performance. By using the financial data from manufacturing corporations in the Korea Stock Exchange (KSE) list, we will discuss some experiences learned from the procedure of sampling scheme, variable transformation, imputation, variable selection, and model evaluation. Finally, implications of the model with repeated measurement and future direction of research will be discussed.

• Korean Journal of Child Studies
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• v.31 no.1
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• pp.1-17
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• 2010

This study explored the differences in gender, developmental period and parents in terms of parenting, the cross-sectional and longitudinal relationships in parenting by gender, and the cross-sectional and longitudinal relationships between participant roles in bullying situations and parenting by gender. The subjects were 498 4-5th grade children and the instruments utilized in this study were the Parental Bonding Instrument (Bowers, Smith, & Binney, 1994) and the Participant Roles Scale (Sutton & Smith, 1999). The subjects were contacted again one year after the first contact. Results showed that the relationships between parents were longitudinally quite stable. Girls whose fathers had higher levels of accurate monitoring were more likely to be defenders cross-sectionally. Girls whose parents had more accurate monitoring were less likely to be victims longitudinally. The results underscore the importance of examining both gender and participant roles in bullying situations.

• Phonetics and Speech Sciences
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• v.5 no.2
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• pp.71-79
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• 2013

This study provided longitudinal examination of the Chinese learners' acquisition of the Korean vowels. Specifically the author examined whether Korean monophthongs are acquired rapidly in early stages of learning (Flege, Munro and Skelton, 1992; Munro and Derwing, 2008) or they develop rather gradually in proportion to the learners' experience (Byee, 2001; Ellis, 2006). This study collected the Korean vowel production by 23 Chinese learners for a year, and then analysed F1 and F2 of each Korean vowel. The results showed that 1) Most of the second language (L2) vowels were rapidly improved during the first six or nine months of Korean learning before reaching the constant stage; and 2) The exact acquisition trajectories varied across the seven vowels. Specifically the vowels which were acquired in the early stage of learning were /i, e, ɨ/ for F1 and /ʌ, e, o, u/ for F2. Thus this study supports the hypothesis of Flege et al. (1992) and Munro and Derwing (2008) except the fact that each vowel showed the different learning route.

• Asia pacific journal of information systems
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• v.15 no.2
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• pp.121-148
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• 2005

This study focuses on MRO e-Marketplace and attempts to research how companies select the structure of e-Marketplace governance and how it influences purchasing performance. Furthermore, a longitudinal study is conducted to analyze the dynamic relationship between variables in our research model. The research gives the following results. First, as the utilization level of e-Marketplace increases, the level of relational exchange between purchasing company and e-Marketplace increases. The increased utilization level enhances purchasing efficiency rather than reducing purchasing price. Secondly, as the level of relational exchange between purchasing companies and e-Marketplace increases, system integration increases, whereas supply externality decreases. Accordingly, system integration improves purchasing efficiency, whereas the low supply externality does not help lower purchasing price. Third, compared to the initial growth stage, the stable stage of e-Marketplace has the significantly increased level of relational exchange and purchasing efficiency through system integration, rather than the reduction of purchasing price by supply externality.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.1
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• pp.37-43
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• 2009

This paper deals with designing a ground-based longitudinal landing controller which is robust to datalink time delays. Time delays occur because forward velocity measurements are downlinked and the controller output commands are uplinked. An $H_{\infty}$ controller was designed by using the input/output decomposition where time delay is modeled as a first-order system with Pade approximation. Linear simulations show that the system tracks well the predefined path and is robust to the variation of time delay.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.102-107
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• 2013

It is important to understand the vibrating behavior of plate structures for many engineering applications. In this study, vibration characteristics of strip plates which have finite width and infinite length are investigated theoretically and numerically. The waveguide finite element approach is used in this study which is known as an effect tool for waveguide structures. WFE method requires only cross-sectional FE model and uses theoretical harmonic solutions for the wave propagation along the longitudinal direction. First of all for a simple strip plate, WFE results are compared with theoretical ones such as the dispersion diagrams, point mobilities, etc. to validate the numerical model. Then in the numerical analysis, the several different types of longitudinal stiffeners are included to the plate model to investigate the effects of the stiffeners in terms of the dispersion curves and mobilities.

• International Journal of Contents
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• v.15 no.3
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• pp.7-12
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• 2019

The purpose of this study was to analyze characteristics and patterns of 'better class' by using the longitudinal text mining big data analysis technique from subjective lecture evaluation comments. First, this study classified upper 30% classes to deduce certain characteristics and patterns from every five-year subjective text data for 10 years. A total of 47,177courses (100%) from spring semester 2005 to fall semester 2014 were analyzed from a university at a metropolitan city in the mid area of South Korea. This study extracted meaningful words such as good, course, professor, appreciation, lecture, interesting, useful, know, easy, improvement, progress, teaching material, passion, and concern from the order of frequency 2005-2009. The other set of words were class, appreciation, professor, good, course, interesting, understanding, useful, help, student, effort, thinking, not difficult, explanation, lecture, hard, pleasant, easy, study, examination, like, various, fun, and knowledge 2010-2014. This study suggests that the characteristics and patterns of 'better class' at college, should be analyzed according to different academic code such as liberal arts, fine arts, social science, engineering, math and science, and etc.

• Journal of Korean Academy of Rural Health Nursing
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• v.5 no.1
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• pp.33-39
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• 2010

Purpose: This study was done to identify change in self-concept of smoking experience in middle school students. Method: The study was a longitudinal survey design and used only the responses on self-concept and smoking state from the data of the Korea Youth Panel Survey (KYPS). The sample for this study consisted of 3,449 middle school students and the data were collected over a two-year period (2003-2004). Results: Self-esteem scores for the first and second year were significantly higher and self-stigma and aggression scores were significantly lower in the non-smoking maintenance group. There was a significant increase in self-esteem scores for students in second year who quit smoking compared to those in first year. There was a significant decrease in scores for attachment to surrounding people and emotional sense of control in second year students compared to those first year for students in the non-smoking maintenance group and the group that quit smoking. Self-intimacy scores were significantly lower in the smoking maintenance group. There was a significant increase in sex-role identity scores in second year students compared to those in first year for students in the group who newly started smoking. Conclusion: Findings from this study can contribute to designing appropriate smoking prevention strategies to improve self-constructs related smoking experiences in adolescents.

• The Journal of Korean Association of Computer Education
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• v.20 no.3
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• pp.35-46
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• 2017

The purpose of this study is to analyse the longitudinal relations between creativity, academic achievements, and utilization of computer & smartphone of middle school students. For this purpose, multivariate latent growth model was verified, using three year longitudinal panel data of Seoul Educational Longitudinal Study(2013-2015). Results indicated that the more students in their first year used computer & smartphone, the better scores they obtained on the creativity and academic achievements. As their grade goes up, while the growth rates of using computer & smartphone and creativity were related positively, the growth rates of using computer & smartphone and academic achievements -even though it was not statistically significant- were related negatively. In addition, the first year students, who obtained high level of scores on the creativity, obtained high level of scores on academic achievements, but this tendency was not significant as their grade goes up.

• Korean Journal of Childcare and Education
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• v.12 no.5
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• pp.137-155
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• 2016

The purpose of the present study was to investigate the longitudinal relationship between main caregivers' life satisfaction and depression and self-esteem of school-aged children, and to provide plans for improving the lives of the school-aged children. For this purpose, we analyzed the three years'longitudinal panel data (2011-2013) of the Korean Children and Youth Panel Survey (KCYPS) including 2,342 first grade elementary school children employing the latent growth model using SPSS 18.0 and AMOS 22.0. Analysis results were as follows. First, main caregivers'life satisfaction and school-aged children's depression increased as time passes and linear change model was selected. Second, the initial status of main caregivers'life satisfaction had effects on the initial status of their children's depression, but initial status and rates of change of life satisfaction did not have an influence on the rates of change of the depression. However, it was found that the main caregivers' life satisfaction had effects on the school-aged children's self-esteem and it worked as a mediator on the longitudinal relationship between the main caregivers'life satisfaction and the children's depression. School-aged children's self-esteem was a partial mediator on the initial status of their depression and full mediator on these rates of change. These findings suggests that programs improving school-aged children's self-esteem should be developed.