• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.6.1-6.15
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• 2023

Background: Polycyclic aromatic hydrocarbons (PAHs) are occupational and environmental pollutants generated by the incomplete combustion of organic matter. Exposure to PAHs can occur in various occupations. In this study, we compared PAH exposure levels among occupations based on 4 urinary PAH metabolites in a Korean adult population. Methods: The evaluation of occupational exposure to PAHs was conducted using Second Korean National Environmental Health Survey data. The occupational groups were classified based on skill types. Four urinary PAH metabolites were used to evaluate PAH exposure: 1-hydroxypyrene (1-OHP), 2-naphthol (2-NAP), 1-hydroxyphenanthrene (1-OHPHE), and 2-hydroxyfluorene (2-OHFLU). The fraction exceeding the third quartile of urinary concentration for each PAH metabolite was assessed for each occupational group. Adjusted odds ratios (ORs) for exceeding the third quartile of urinary PAH metabolite concentration were calculated for each occupational group compared to the "business, administrative, clerical, financial, and insurance" group using multiple logistic regression analyses. Results: The "guard and security" (OR: 2.949; 95% confidence interval [CI]: 1.300-6.691), "driving and transportation" (OR: 2.487; 95% CI: 1.418-4.364), "construction and mining" (OR: 2.683; 95% CI: 1.547-4.655), and "agriculture, forestry, and fisheries" (OR: 1.973; 95% CI: 1.220-3.191) groups had significantly higher ORs for 1-OHP compared to the reference group. No group showed significantly higher ORs than the reference group for 2-NAP. The groups with significantly higher ORs for 1-OHPHE than the reference group were "cooking and food service" (OR: 2.073; 95% CI: 1.208-3.556), "driving and transportation" (OR: 1.724; 95% CI: 1.059-2.808), and "printing, wood, and craft manufacturing" (OR: 2.255; 95% CI: 1.022-4.974). The OR for 2-OHFLU was significantly higher in the "printing, wood, and craft manufacturing" group (OR: 3.109; 95% CI: 1.335-7.241) than in the reference group. Conclusions: The types and levels of PAH exposure differed among occupational groups in a Korean adult population.

• Journal of the Korean Data and Information Science Society
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• v.17 no.2
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• pp.559-568
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• 2006

In this paper, we develop the noninformative priors for the linear mixed models when the parameter of interest is the ratio of variance components. We developed the first and second order matching priors. We reveal that the one-at-a-time reference prior satisfies the second order matching criterion. It turns out that the two group reference prior satisfies a first order matching criterion, but Jeffreys' prior is not first order matching prior. Some simulation study is performed.

• 한국데이터정보과학회:학술대회논문집
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• 2005.10a
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• pp.27-34
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• 2005

We consider the problem of estimating the system reliability noninformative priors when both stress and strength follow generalized gamma distributions. We first derive Jeffreys' prior, group ordering reference priors, and matching priors. We investigate the propriety of posterior distributions and provide marginal posterior distributions under those noninformative priors. We also examine whether the reference priors satisfy the probability matching criterion.

• Journal of the Korean Data and Information Science Society
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• v.18 no.1
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• pp.247-257
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• 2007

In this paper, we develop the noninformative priors for the common shape parameter in the gamma distributions. We develop the matching priors and reveal that the second order matching prior does not exist. It turns out that the one-at-a-time reference prior and the two group reference prior satisfy a first order probability matching criterion. Some simulation study is peformed.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.808-812
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• 1998

A new SPWM control method for Uninterrupted Power System(UPS) is presented. A triangle waveform is used as the reference signal. The desired SPWM control signal can be obtained more easily with a group of comparators. The output AC voltage can be regulated by controlling the lower reference and the upper reference of the comparators according to the feedback voltage. Basic principle, an actual circuit and the experimental results on a 500W UPS for computer system is discussed as an example.

• Journal of the Korean Statistical Society
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• v.36 no.1
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• pp.77-91
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• 2007

This paper considers development of noninformative priors for the familial data when the families have equal number of offspring. Several noninformative priors including the widely used Jeffreys' prior as well as the different reference priors are derived. Also, a simultaneously-marginally-probability-matching prior is considered and probability matching priors are derived when the parameter of interest is inter- or intra-class correlation coefficient. The simulation study implemented by Gibbs sampler shows that two-group reference prior is slightly edge over the others in terms of coverage probability.

• The Research Journal of the Costume Culture
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• v.7 no.6
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• pp.28-40
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• 1999

The purpose of this study was to understand the Korean teenagers\` clothing behavior through pointing out the factors that clothing behavior of teenagers that was initiated from the important reference group, TV stars. The subject of this study were 570 purposively selected students at female middle and high school students in Seoul. The results were as follows : 1. The clothing conformity to TV stars relating to demographic variables was influenced significantly by location and personal expense variable in the high school group. 2. The exhibition showed a more important role to the clothing conformity in middle school group than in high school group. 3. The clothing conformity to TV stars relating to the clothing related variables was significantly affected by self-confidence to clothing than clothing normative recognition, clothing risk recognition and degree of clothing importance regardless of groups. 4. The clothing conformity to TV stars relating to TV media variables was affected by TV media star identification variable in both groups. And in case of middle school group, interests in TV stars also had influence on the clothing conformity to TV stars. And in case of high school group, interests in TV had effect on the imitation to TV stars\` clothing. As middle school students tend to have self-identification about a particular person, TV media stars become the reference group for the adolescence to follow their clothing.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.6
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• pp.546-553
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• 2008

Purpose: The purpose of this study was to estimate validity of posterior anterior cephalometric and 3D-CT for orbital canting analysis. Materials and methods: Three trained observers classified two patients group using standardized frontal photographs of facial asymmetry patients. Group A consisted of patients with facial asymmetry and orbital canting(n=19), and group B consisted of patients with only facial asymmetry(n=43). Orbital canting was measured with line of bilateral inferior orbitale. Orbital canting measurement was done with posterior anterior cephalometric and 3D-CT. Each horizontal reference line was established by bilateral GWSO(cephalometric), FZS(3D-CT). Maxillary canting and mandibular deviation angle were also measured and analyzed with orbital canting. Results: The mean orbital canting was $3.03{\pm}1.00^{\circ}$ in Group A and $1.11{\pm}0.76^{\circ}$ in Group B in frontal photograph. The mean orbital canting was $1.20{\pm}0.74^{\circ}$ in group A and $1.22{\pm}0.65^{\circ}$ in group B by cephalometric analysis(p>0.05). In 3D-CT, orbital canting was almost paralleled with horizontal reference line. The orbital canting, maxillay canting and mandibular deviation between two groups showed no significant differences except madibular deviation in 3D-CT. Conclusion: Common analysis of posterior anterior cephalometric and 3D-CT is not valide method to evaluate orbital canting for facial asymmetry patients with orbital canting.

• Journal of Families and Better Life
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• v.9 no.1 s.17
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• pp.145-160
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• 1991

The purpose of this study is to suggest some fundamental data for the welfare of consumers by investigation some characteristics of the housewives and their attitudes toward a famous brand. For the purpose of this study, the samples were distributed to houswives who lived in Seoul. The 493 data obtained were analyzed by frequency distribution, percentile, $X^2$-test, t-test, F-test, Pearson's correlation, Duncan's multiple range test and Stepwise multiple regression analysis. The major finding were follows ; The major finding were follows ; 1) In general the score for the brand preference of the housewives was somewhat high. There were significant differences between the brand preference of the housewives and the socio-demographic, reference group variables. 2) There were significant differences between the brand image of housewives and the socio-demographic, reference group variables 3) In general the score for the dissatisfaction of the housewives was somewhat low. There were significant differences between the dissatisfaction the housewives and the socio-demographic variables. 4) The brand preference of the housewives had a positive relationship with the level of their dissatisfaction. 5) The most influential variables for the brand preference of the housewives was in the rank of reference group, income, education level.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.353-360
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• 2020

The main aim of study is to identify the factors that affect the purchasing intention of young adults. The reference group is an important factor in determining the underlying causes of young adults' purchasing intentions. However, the literature states that young adults prefer to buy brands they trust in order to eliminate the risks that may arise when buying products they may not know. Moving from this perspective, the study proposes a conceptual model that including structural relationships between brand trust, reference group, and purchasing intention. The study aims to contribute to the literature by discussing the moderator role of brand trust in this structure. A series of hypotheses are tested via a survey completed by 749 young people between the ages of 20 and 30 living in Istanbul, Turkey. The data were analyzed with IBM SPSS-23 and AMOS-18 program. In addition to descriptive, reliability, and factor (exploratory and confirmatory) analysis, hierarchical regression analysis was performed to test the research hypotheses. The results show that the reference group positively influences the purchasing intention, and brand trust plays a moderating role in this relationship. The findings are discussed and some practical suggestions are made for mobile phone manufacturers.