• 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.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.1-13
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• 1999

Even though there is no fit test regulations in Korea, in many developed countries, respirator fit testing is required before entering specific work environment to ensure that the respirator worn satisfies a minimum of fit and that the user knows when the respirator fits properly. Due to no regulation for fit test, a lot of Korean workers wearing respirators may be potentially exposed to hazards. Anthropometric test panels for testing the fit of respirators are very important to develop respirators fitted properly for Korean workers. To evaluate the fitting performance, 304 workers (272 males, 32 females) and 536 students (268 male, 268 females) were fit tested for 4 full-facepieces (2 domestic-made S, C, and 2 foreign-made T, N), 2 half masks (1 domestic-made S, and 1 foreign-made T) and 3 quarter masks (2 domestic-made S, C, and 1 foreign-made T) with PortaCount 8020. Fit factors of foreign-made masks were higher than those of domestic-made masks in all types. Males were fitted more properly than females. A facial dimension survey of 364 workers (339 males, 25 females) and 158 students (69 males, 89 females) was conducted to develop test panels for fit testing. Subjects were selected on the basis of face length and face width to wear full-facepiece masks in test. For testing half- and quarter masks, face length and lip length were used. Test panels containing 25 male-and-female subjects and 16 male subjects were respectively developed for full-facepiece, and half-and quarter masks to represent a majority of population surveyed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.3
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• pp.279-291
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• 2024

Objective: This was to develop headforms for the labor population, based on a three-dimensional(3D) face dimensions data base(DB) and a principal component analysis(PCA) fit test panel, in selection, use and maintenance of respirators in Korea. Methods: This study was part of a two-year-project initiated in 2021. The study was designed and conducted in line with ISO 16976-2 while subjects were those employed in the development of the PCA fit test panel. The approaches included literature review; examination on conformity of the 3D face dimensions DB; and development of headforms representing the labor population. The mean data were used in order to construct each model of the headforms through a way of 3D modeling and 3D printing technology. Results: A total of 2,752 subjects were determined. Five models of headforms(small, medium, large, long-narrow, short-wide) were completely constructed for the labor population. For example, means of the 10 face dimensions for medium headform model were: minimum frontal breadth 106 mm, face width 136 mm, jaw width 127 mm, face length 111 mm, interpupillary distance 69 mm, head breadth 164 mm, nose protrusion 12 mm, nose breadth 34 mm, nasal root breadth 35 mm, and nose length 50 mm. Conclusions: Five models of headforms were newly constructed using the study data. It is likely desirable that the constructed headforms, together with the 3D face dimensions DB as well as the PCA fit test panel, can be utilized more effectively in selection, use and maintenance of respirators for users including the labor population.

• Journal of Fashion Business
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• v.22 no.5
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• pp.96-112
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• 2018

This study developed the pants pattern, that improved appearance and gesture functions in clothes to resolve inconveniences in case of activities with being adequate in fitness of slim-fit pants for obese adolescents. The slim-fit pants pattern was developed through the fitting test after designing and making the pattern of the experimental clothing A(c/pu; 99/1%) with the primary commercial clothing as basic prototype, through the fitting test and implementation of the experimental clothing, modified and supplemented secondarily, and through the fitting test of the second experimental clothing, modified and supplemented tertiary. In terms of findings, first, as a result of analyzing the commercial slim-fit pants, it is interpreted to have projected an optical illusion, that appears to be slim due to being narrow in width of the front panel when observed from the front of the pants. Second, in the fitting test of the first experimental clothing, the prototype of commercial clothing was understood to have improved butt, crotch, waist and femoral regions. Third, pattern design of the second experimental clothing was allowed to decline abdominal pressure, in case of the sitting position, by making the crotch line in the front panel short and by handling it with a yoke belt, and was processed a difference between waist and hip circumference in the back panel, with a rubber band in the whole waist part. Fourth, in the gesture function test of the third experimental clothing, high evaluation was received in every item excluding the knee region.

• 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.

• The Korean Journal of Applied Statistics
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• v.27 no.7
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• pp.1163-1170
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• 2014

The concepts and structure of intermittent panel time series data are introduced. We suggest a Wald test statistic for the test of homogeneity for intermittent panel first order autoregressive model and its limit distribution is derived. We consider the fitting the model with pooling data using sample mean at the time point if homogeneity for intermittent panel AR(1) is satisfied. We performed simulations to examine the limit distribution of the homogeneity test statistic for intermittent panel AR(1). In application, we fit the intermittent panel AR(1) for panel Mumps data and investigate the test of homogeneity.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.123-132
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• 2016

We can achieve the principle of parsimony and efficiency if homogeneity for panel time series model is satisfied. We suggest a Rao test statistic and a Wald test statistic for the test of homogeneity for panel AR(1) and derived the limit distribution. We performed a simulation to examine statistics with the same chisquare distribution when number of the individual is small and in common with large. We also simulated to compare the empirical power of the statistics in a small panel. In application, we fit panel AR(1) model using regional monthly economical active population data and test homogeneity for panel AR(1). It is satisfied homogeneity, so it could be fitted AR(1) using the sample mean at the time point. We also compare the power of prediction between each individual and pooled model.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.100-105
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• 1998

Image processing was used to recognize parts at various disposition. Non-transpatent tachometer panel for automobile and semi-transparent panel have been used as test specimen. Laplacian filter and various threshold values have been applied for preprocessing and edge following algorithm has been applied. Series of length data between edges have been generated from each image and compared using cross correlation coefficient. The result using cross correlation coefficient. The result using both edge following and cross correlation coefficient was proven to be the best fit for the proposed parts.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.356-363
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• 2016

Purpose: The purpose of this study is to propose efficiency of equipment testing the luminance degradation of OLED. Methods: The degradation model of Exponential model and Stretched exponential model is analyzed by goodness of fit test using calculated R-square. The degradation model having the higher R-square is finally selected. Scale parameter and Shape parameter using the selected degradation model is estimated. The activation energy and current density n using peck model among the accelerated model is estimated. the estimated parameters are analyzed by t-test. Results: The results of t-test show that the estimated parameters on chamber and hotplate are equal statistically. we can know the similarity of the luminance degradation rate and degradation pattern on chamber and hotplate. Conclusion: The result of the degradation test on chamber and hotplate is similar. when the accelerated degradation test on the panel of the OLED TV is performed, hotplate is requiring less samples, time and cost than chamber. so the accelerated degradation test on the panel of the OLED TV using the hoplate is efficient of time and cost.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.169-176
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• 1988

In order to obtain the objective indices which can assess the quality and the shelf-life of dried squid, nonenzymatic browning, carbonyl value, trimethyl amine (TMA) and trimethyl amine oxide (TMAO) decrease and panel test were determined in dried squid at various water activity levels. When the data of nonenzymatic browning fit a zero order equation, $r^2$ value were more than 0.92 except aw 0.52 for 0.8241. Through variance analysis for the data of browning extent and TMAO decrease, the confidence limits of regression equation were $99\%$ and their limit values of shelf-life were shown 0.45390 O. D./g. solid and 190.322 g/g respectively. In case of TMAO, $r^2$ value was calculated more than 0.95. Linear regression equation for the correlation between browning data and average panel score was Y=0.6138-0.053X and its $r^2$ value was 0.9285. Also in TMAO decrease, the equation was InY=2.0314+0.08269x and $r^2$ value was 0.7854. The shelf-life, evaluated by nonenzymatic browning, TMAO decrease and panel test, was 110-170 days at aw 0.45-0.76 except aw 0.15.