• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.145-155
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• 2023

Objectives: A fit test panel is needed to identify the fit performance of a respirator and its face seal. This is a criterion for selecting subjects that can represent the facial characteristics of users. Although anthropometry data has been developed for people in United States and China it is not yet present in Korea. This study aimed to develop a Korean fit test panel and test headform. Methods: For the 7th and 8th waves of the Size Korea anthropometry data, facial measurements of 11,429 people aged 15 to 69 years were used for analysis. PCA and bivariate panel were classified using the ISO16976-2:2022(E) anthropometrics analysis method. Based on this result, a static headform was developemed and a fit test chamber was constructed. Results: Of the 11,429 Korean people used for principal component analysis, 11,300 were included in the ellipse, marking an acceptance rate of 98.87% on PCA panel. The face types were classified into five types. Among them, a large, medium, and small static headform were printed using a 3D printer. In addition, 10,985 people (96.12%) were included in the bivariate panel based on face length and face width. The y-axis (face length) boundary was 97.87 to 134.59 mm, and the x-axis (face width) boundary was 120.75 to 158.23 mm. Conclusions: Compared to the ISO analysis, the Korean principal component was narrower in the width item (PC1) and longer in the length item (PC2). For the future, it is necessary to conduct a fit test using the developed headform and chamber device to confirm the usefulness of this Korean test panel. Therefore, this study is considered valuable as basic research for Korean test panels.

• Korean Journal of Organic Agriculture
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• v.17 no.4
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• pp.413-439
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• 2009

This study conducts a survey and test to understand U.S. public's perception about multifunctionality. The questionnaire suggests seven alternative way of providing questions about intangible benefits provided by agriculture in the U.S. The final questionnaire was administered as an e-mail survey in June 2008 to a nationally representative household panel maintained in the U.S. by the Ipsos Observer. Data analysis shows that 64 percent of respondents considered the multifunctionality of agriculiture as an important issue and 45 percent of respondents were in favor of increasing government expenditure to support farmland preservation. Using Fishbein's multi-attribute model as a theoretical background, this paper develops an empirical model to assess and attributes of multifunctionality. For the analysis, bivariate orderd probit model was set up to reflect respondent's attitude. Regression analyses show that two questions (how much you agree with agriculture's intangible benefit and increasing government expenditure to support agriculture) are shaped by different sets of facts.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.247-264
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• 2023

Objectives: The study was to examine the features of three-dimensional(3D) face dimensions and to develop fit test panels for the labor population using respirators in South Korea. Methods: This study was part of the first-year work of a two-year-project conducted at Occupational Safety and Health Research Institute in 2021. After 3D head dimensions data were collected from Size Korea Center managing Sixth Size Korea databases, 3D face dimensions DB for the South Korean labor population was established for 21 items of face dimensions in line with the ISO/TS 16976-2 and KS A ISO 15535. With the South Korean labor population 3D face dimensions DB, in accordance with the ISO/TS 16976-2, the descriptive statistics of 3D face dimensions were calculated and two fit test panels were developed. Results: A total of 2,752 subjects were finally determined and they were 52.9% for male, 41.2% for the highest age-group of 15-29, and residents in the capital area. Mean and standard deviation were obtained for each of the 21 3D face dimensions items for the South Korean labor population. Among the items, male and female face widths were 137.6±5.7 mm, 133.2±5.0 mm, respectively. Male and female face lengths were 116.6±7.0 mm, 107.8±6.8 mm, respectively. Two new South Korean fit test panels, a bivariate test panel and a principal component analysis test panel, were developed using the 3D face dimensions DB as well. Conclusions: Using the 3D face dimensions DB, the mean and standard deviation were featured for each of the 21 items and also the two fit test panels were newly developed in the study. It is suggested that the study outputs should be utilized practically and effectively in selection, use, and management of respirators at work, expecting that respiratory protection can be furthermore improved for respirator users including labor population across the country.

• Journal of Preventive Medicine and Public Health
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• v.49 no.5
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• pp.260-274
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• 2016

Objectives: Previous epidemiological studies about oxidative stress and depression are limited by hospital-based case-control design, single-time measurements of oxidative stress biomarkers, and the small number of study participants. Therefore, in this study, we analyzed the association between biomarker of oxidative stress and depressive symptom scores using repeatedly measured panel data from a community-dwelling elderly population. Methods: From 2008 to 2010, a total of 478 elderly participants residing in Seoul, Korea, were evaluated three times. Participants underwent the Korean version of the Short Form Generic Depression Scale (SGDS-K) test for screening depression, and urinary malondialdehyde (MDA) levels were measured as an oxidative stress biomarker. We used a generalized estimating equation with a compound symmetry covariance structure to estimate the effects of oxidative stress on depressive symptom scores. Results: A two-fold increase in urinary MDA concentration was significantly associated with a 33.88% (95% confidence interval [CI], 21.59% to 47.42%) increase in total SGDS-K scores. In subgroup analyses by gender, a two-fold increase in urinary MDA concentration was significantly associated with increased SGDS-K scores in both men and women (men: 30.88%; 95% CI, 10.24% to 55.37%; women: 34.77%; 95% CI, 20.09% to 51.25%). In bivariate analysis after an SGDS-K score ${\geq}8$ was defined as depression, the third and the fourth urinary MDA quartiles showed a significantly increased odds ratio(OR) of depression compared to the lowest urinary MDA quartile (third quartile OR, 6.51; 95% CI, 1.77 to 24.00; fourth quartile OR, 7.11; 95% CI, 1.99 to 25.42). Conclusions: Our study suggests a significant association between oxidative stress and depressive symptoms in the elderly population.

• Korean Journal of Social Welfare
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• v.67 no.3
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• pp.281-303
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• 2015

This study examined the interdependent retirement decision between husbands and wives. Since most of retirees in Korea retired by involuntary reasons such as health problems, it purposes to test whether the involuntary retirement of husbands(wives) influences the retirement decision of wives(husbands). Using data from 4th Korean Longitudinal Study of Ageing Panel, it conducted probit and multivariate probit analysis on 1,038 dual-earner couples aged 51~76 to test interdependence of couples' retirement. The results showed that husbands who have retired wife were more likely to retire. It also proved that involuntary retirement of spouse is a significant predictor of early retirement decision, though the direction of the effect is reversed by gender. Wives were more likely to retire when husband were retired involuntarily, while husbands were more likely to stay in labor market. These findings helped to understand the retirement decision of aged couples in Korea and brought suggestion on labor market and care policies for aged couples.