• Communications for Statistical Applications and Methods
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• v.11 no.1
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• pp.49-58
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• 2004

In this talk we proposed an asymptotic test for dimensionality in the latent variable model for probabilistic principal component analysis with missing values at random. Proposed algorithm is a sequential likelihood ratio test for an appropriate Normal latent variable model for the principal component analysis. Modified EM-algorithm is used to find MLE for the model parameters. Results from simulations and real data sets give us promising evidences that the proposed method is useful in finding necessary number of components in the principal component analysis with missing values at random.

• Journal of the Korean Chemical Society
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• v.31 no.4
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• pp.295-300
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• 1987

Spectroscopic studies have been carried out on the metachromatic behavior of methylene blue(MB) and acridine orange(AO) in the presence of chondroitin sulfate A(CSA) and chondroitin sulfate C(CSC). The characteristic changes of the meta-band with the changes of P/D value are discussed in terms of the stacking theory. Quantitative studies on the stacking effect are made to calculate the number of bound molecules of dye per unit molecule of the polyanion. The result shows that MB has stronger stacking effect than AO. A stacking model and the dimension of the bound dyes on the surface of the polyanion are proposed, on the basis of the dimer model of planar aromatic dyes and the most stable conformation of the CSA chain. The model is found to be reasonable in accordance with the experimental results.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.331-339
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• 2020

The purpose of this study was to develop and validate future teacher competencies diagnosis tools required for pre-service teachers. In this study, the hypothesis model was established by hierarchizing basic competency and job competency in three dimensions such as knowledge, practice, and personality as teachers' competencies required in future society. Based on this hypothesis model, 54 preliminary questions were developed, and competencies diagnosis test was conducted for 237 pre-service teachers in J area, Korea. The results of this study are as follows: First, as a result of this study, a total of 53 questions were extracted, including 18 questions with 6 factors in the knowledge dimension, 17 questions with 6 factors in the practice dimension, and 18 questions with 6 factors in the personality dimension. Second, the goodness-of-fit of future teacher competencies diagnosis model required was verified, and convergence and discriminant validity were verified. The results of this study were discussed. Finally, the implications and suggestions for further research were presented.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.699-709
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• 2011

The uses of multi-dimensional hydrodynamic and water quality models are increasing to support a sustainable management of large dam reservoirs in Korea. Any modeling study requires selection of a proper spatial dimension of the model based on the characteristics of spatial variability of concerned simulation variables. For example, a laterally averaged two-dimensional (2D) model, which has been widely used in many large dam reservoirs in Korea, assumes that the lateral variations of hydrodynamic and water quality variables are negligible. However, there has been limited studies to give a justification of the assumption. The objectives of this study were to present the characteristics of spatial variations of water quality variables through intensive field monitoring in Daechung Reservoir, and provide information on a proper spatial dimension for different water quality parameters. The monitoring results showed that the lateral variations of water temperature are marginal, but those of DO, pH, and conductivity could be significant depending on the hydrological conditions and local algal biomass. In particular, the phytoplankton (Chl-a) and nutrient concentrations showed a significant lateral variation at R2 (Daejeongri) during low flow periods in 2008 possibly because of slow lateral mixing of tributary inflow from So-oak Stream and wind driven patchiness.

• Safety and Health at Work
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• v.13 no.2
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• pp.170-179
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• 2022

Background: The vulnerability of international migrant workers is on the rise, affecting the frequency of occupational accidents at workplaces worldwide. If migrant workers are managed in the same way as native workers, the consequences on safety assurance and risk management will be significant. This study aimed to develop the vulnerability factor model for migrant workers in seafood processing industries because of significant risk-laden labor of Thailand, which could be a solution to control the risk effectively. Methods: A total of 569 migrant workers were surveyed (432 Burmese and 137 Cambodian), beginning with 40 initial vulnerability factors identified in the questionnaire established from experts. The data were analyzed through descriptive analysis; exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to ascertain the model. Results: The result of content validity >0.67 and the Cronbach's alpha of 0.957 specified the high reliability of 40 factors. The EFA indicated a total variance of 65.49%. The final CFA validated the model and had an empirical fitting; chi-square = 85.34, Adjust Goodness-of-Fit Index = 0.96, and root mean square error of approximation = 0.016. The structure concluded with three dimensions and 18 factors. Dimension 1 of the structure, "multicultural safety operation," contained 12 factors; Dimension 2, "wellbeing," contained four factors; and Dimension 3, "communication technology," contained two factors. Conclusion: The vulnerability factor structure developed in this study included three dimensions and 18 factors that were significantly empirical. The knowledge enhanced safety management in the context of vulnerability factor structure for migrant workers at the workplace.

• Korean Journal of Health Education and Promotion
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• v.26 no.1
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• pp.1-13
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• 2009

Objectives: This study was conducted to estimate the health-related quality of life (HRQOL) using EuroQoL-5 Dimension (EQ-5D) and to identify its related factors among urban-dwelling adults. Methods: The data for this study were obtained from 1,134 subjects aged $20\sim91$, who participated in 'Survey on the health status and demand for health' in two cities of Korea (Dong-gu, Gwangju and Suncheon-si, Jeollanamdo). The HRQOL was measured using the EQ-5D instrument and EQ-5D index scores were calculated by two Korean valuation study model using time trade-off method. Results: The mean EQ-5D index scores for all subjects were $0.865{\pm}0.218$ (model A), and $0.921{\pm}0.170$ (model B). The EQ-5D index score was significantly different according to demographic and socioeconomic characteristics (gender, age, marital status, education, occupation, income, and health security system), self-rated health condition, health-related psychological assessments (enough sleep, fatigue rate, stress rate, and degree of satisfaction on the residence). The results of multiple linear regression showed that age, marital status, income, coverage of medical insurance, self-rated health condition, and fatigue rate were significantly related common statistical factors of HRQOL in two Korean valuation study model. Conclusion: Among the adults residing in urban environment, the HRQOL was significantly lower on the subjects with following conditions: higher age, being alone without a spouse as a result of death, divorce or separation, low income, medical aid program, poor self-rated health condition, and chronic fatigue. In order to improve the urban adults' quality of life, healthcare policy and health promotion program must be developed with considerations to factors related to the HRQOL.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1066-1073
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• 2017

Objective: Growth-related traits are important economic traits in the swine industry. However, the genetic mechanism of growth-related traits is little known. The aim of this study was to screen the candidate genes and molecular markers associated with body dimension and body weight traits in pigs. Methods: A genome-wide association study (GWAS) on body dimension and body weight traits was performed in a White $Duroc{\times}Erhualian$ $F_2$ intercross by the illumina PorcineSNP60K Beadchip. A mixed linear model was used to assess the association between single nucleotide polymorphisms (SNPs) and the phenotypes. Results: In total, 611 and 79 SNPs were identified significantly associated with body dimension traits and body weight respectively. All SNPs but 62 were located into 23 genomic regions (quantitative trait loci, QTLs) on 14 autosomal and X chromosomes in Sus scrofa Build 10.2 assembly. Out of the 23 QTLs with the suggestive significance level ($5{\times}10^{-4}$), three QTLs exceeded the genome-wide significance threshold ($1.15{\times}10^{-6}$). Except the one on Sus scrofa chromosome (SSC) 7 which was reported previously all the QTLs are novel. In addition, we identified 5 promising candidate genes, including cell division cycle 7 for abdominal circumference, pleiomorphic adenoma gene 1 and neuropeptides B/W receptor 1 for both body weight and cannon bone circumference on SSC4, phosphoenolpyruvate carboxykinase 1, and bone morphogenetic protein 7 for hip circumference on SSC17. Conclusion: The results have not only demonstrated a number of potential genes/loci associated with the growth-related traits in pigs, but also laid a foundation for studying the genes' role and further identifying causative variants underlying these loci.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.171-179
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• 2017

Severely worn dentition is frequently multifactorial. It is crucial that the etiology of excessive wear be determined, but accurately diagnosing the factors responsible for tooth wear is often confusing. Before initiating the treatment of these cases, meticulous examination and determining vertical dimension are essential. A 69-year-old male patient had the chief complaint that he has worn dentition and functional and esthetic discomfort. Based on model analysis and diagnostic wax up, new vertical dimension had been determined. Provisional restorations were cemented and after 5 months permanent prostheses were fabricated. This case reports a satisfactory functional and esthetic clinical outcome achieved by restoring the vertical dimension.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.302-307
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• 2018

Multiple tooth loss and excessive occlusal wear can result in damage to occlusal disharmony, functional disorders and esthetic problems, requiring comprehensive prosthetic treatments. Changing vertical dimension harmonized with surrounding muscle tissue is important. In this case, the patient with loss of vertical dimension caused by severe tooth loss and tooth wear was treated with the analysis of vertical dimension, such as diagnostic model, radiography and various clinical exams. the patient was satisfied with favorable functions and esthetics for 1 years of follow-up.

• The Journal of Information Systems
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• v.14 no.2
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• pp.293-317
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• 2005

Female customers form a major customer group for Internet shopping and their trust on Internet stores seems to be significantly related with their transactions. This paper focuses on female customers' trust on Internet stores, hypothesizing that online service quality has a positive impact on trust and that trust, in turn, together with service quality has a positive effect on loyalty. We investigate trust from three dimensions(benevolence, integrity, and ability) and at the same time, unlike existing research, treat service quality to have five dimensions (intangibles, reliability, responsiveness, assurance, and empathy) as known in SERVQUAL(Parasuraman et al., 1988). Survey data is obtained from the female college student sample. Our research model is justified in terms of construct validity, internal consistency, and goodness of fit. Research hypotheses are tested using SEM(Structural Equation Modeling). The results are as follows: First, assurance and empathy dimensions of service quality have significant impacts on benevolence/integrity dimension of trust. Second, out of the five service quality dimensions, only assurance has a positive effect on ability dimension of trust. Third, assurance dimension of service quality and ability dimension of trust are positively related with customer loyalty. The most important factors for female customers' loyalty are found to be assurance(service quality) and ability(trust). The significance of assurance is in line with findings from existing research. But its relationship with the trust dimensions is uncovered in this research, and the only dimension that impacts on ability is assurance. We find that female customers build trust about internet stores based on their ability rather than on their benevolence/integrity and that the female customers' perception on the internet stores' ability can be improved by higher service quality from the aspect of assurance. Importantly enough, these findings offer practical guidelines to Internet stores to boost female customers' loyalty.