• Journal of Environmental Health Sciences
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• v.18 no.1
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• pp.6-11
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• 1992

This study was carried out to investigate exposure level, size distribution, and respirable mass fraction of airborne coal dust and heavy metal concentration of respirable coal dust at each work site in coal briquet factory from July 1991 to September 1991. Geometric mean of total dust concentration was 10.88mg/m$^{3}$ at storage shop, 8.22mg/m$^{3}$ at pulverize shop, and 3.79mg/m$^{3}$ at rotary press shop, respectively, but those at storage and pulverize shop were higher than TLV. Geometric mean of respirable coal dust concentration wat 1.03mg/m$^{3}$ at storage shop, 0.78mg/m$^{3}$ at pulverize shop, and 0.55mg/m$^{3}$ at rotary press shop, respectively, which were lower than TLV Aerodynamic 50% cutoff diameter of the suspended coal dust was 5$\mu$m at rotary press shop and 6.8$\mu$m at storage shop, ranged to thoracic particulate defined by ACGIH, and deposited in the region of repiratory system. The mass fraction rate of respirable dust to the total coal dust was 26.2% at rotary press shop, 18.8% at storage shop, and 13.8% at pulverize shop, respectively. Heavy metal concentrations of the respirable coal dust were 0.028mg/m$^{3}$ ib Fe, 0.0081mg/m$^{3}$ in Cu, and 0.0039mg/m$^{3}$ in Pb.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1377-1383
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• 2008

Parameterization of a 3D triangular mesh is a fundamental problem in various applications of geometric modeling and computer graphics. There are two major paradigms in mesh parameterization: energy functional minimization and the convex combination approach. In general, the convex combination approach is wifely used because of simple concept and one-to-one mapping. However, the approach has some problems such as high distortion near the boundary and time complexity. Moreover, the stability of the linear system may not be preserved according to the geometric information of the mesh. In this paper, we present an extension of the convex combination approach based on the mean value coordinates, which resolves the drawbacks of the convex combination approach. This may be a more practical solution because it is able to generate a stable linear system in a short time.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.172-183
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• 1995

The airborne concentrations of the welding fumes produced during $CO_2$ arcwelding process at shipbuilding, shiprepairing, container manufacturing and car accessary manufacturing industry were investigated. The effects how much reduced the welding fume were checked when the portable fan was used. The results were as follows; 1.The geometric mean of welding fume concentration in shipbuilding factory was $10.05mg/m^3$. This exposure concentration was higher than other 3 manufacturing industries at 95% confidence level. 2. The sampling filters for welding fume could be digested with acid within 1 hour by microwave oven. The recoveries for investigated metal elements were all over 95%. 3. The optimal wavelength could be selected for the simultaneous analysis of 8 metal elements by ICP(Inductively Coupled Plasma). 4. Noxious gases($O_1,NO_2$) produced during $CO_1$ gas arc welding process were detected that the concentration of ozone($O_1$) was less than 0.01 ppm and that of nitrogen dioxide($NO_2$) was 0.01-0.03 ppm. 5. The geometric mean of welding fume particle diameter was $1.26{\mu}m$ and geometric standard deviation was 1.51 for the counts when particle an analyzer(ELZONE) had been used. 6. When the portable fan had been used,the reduced percent of total welding fume for workers was about 47.8% when portable fan was applied to blow and 71.7% when to exhaust.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.4
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• pp.280-291
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• 2019

Potential utility of 14 candidate housekeeping genes as normalization reference for RT-qPCR analysis with developmental samples (fertilized eggs to late veliger larvae) in Pacific abalone Haliotis discus hannai was evaluated using four different statistical algorithms (geNorm, NormFinder, BestKeeper and comparative ΔCT method). Different algorithms identified different genes as the best candidates, and geometric mean-based final ranking from the most to the least stable expression was as follow: RPL5, RPL4, RPS18, RPL8, RPL7, UBE2, RPL7A, GAPDH, RPL36, PPIB, EF1A, ACTB and B-TU. The findings were further validated via relative quantification of metallothionein (MT) transcripts using the stable and unstable reference genes, and expression levels of MT were greatly influenced according to the choice of reference genes. In overall, our data suggest that RPL5 and RPS18, either singly or in combination, are appropriate for normalizing gene expression in developmental samples of this abalone species, whereas ACTB, B-TU and EF1A are less stable and not recommended. In addition, our findings propose that standard deviations in geometric ranking as well as geometric mean itself should also be taken into account for the final selection of reference gene(s). This study could be a useful basis to facilitate the generation of accurate and reliable RT-qPCR data with developmental samples in this abalone species.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.10
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• pp.2643-2657
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• 2023

Scene graphs are structured representations that can clearly convey objects and the relationships between them, but are often heavily biased due to the highly skewed, long-tailed relational labeling in the dataset. Indeed, the visual world itself and its descriptions are biased. Therefore, Unbiased Scene Graph Generation (USGG) prefers to train models to eliminate long-tail effects as much as possible, rather than altering the dataset directly. To this end, we propose Geometric and Semantic Improvement (GSI) for USGG to mitigate this issue. First, to fully exploit the feature information in the images, geometric dimension and semantic dimension enhancement modules are designed. The geometric module is designed from the perspective that the position information between neighboring object pairs will affect each other, which can improve the recall rate of the overall relationship in the dataset. The semantic module further processes the embedded word vector, which can enhance the acquisition of semantic information. Then, to improve the recall rate of the tail data, the Class Balanced Seesaw Loss (CBSLoss) is designed for the tail data. The recall rate of the prediction is improved by penalizing the body or tail relations that are judged incorrectly in the dataset. The experimental findings demonstrate that the GSI method performs better than mainstream models in terms of the mean Recall@K (mR@K) metric in three tasks. The long-tailed imbalance in the Visual Genome 150 (VG150) dataset is addressed better using the GSI method than by most of the existing methods.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.7-16
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• 1994

This study was designed to establish the relationship between airborne trichloroethylene concentrations and total trichloro-compounds and trichloroacetic acid in urine samples of the trichloroethylene exposed workers, to examine if the biological screening value for trichloroacetic acid in urine set by the Ministry of Labor is appropriate, and to suggest a suitable biological screening value for total trichloro-compounds in urine. Seventy male workers from the cleaning, the packing, and the inspcetion areas were selected as the study group and eighty male office workers were chosen as the control group. The results were as follows: 1. The mean values of total trichloro-compounds and trichloroacetic acid in the exposed group ($48.1{\pm}1.5mg/{\ell}$, $19.7{\pm}1.9mg/{\ell}$) were significantly higher than those in the control group($4.3{\pm}1.5mg/{\ell}$, $1.8{\pm}1.2mg/{\ell}$). 2. The airborne tichloroethylene concentrations were significantly related with the concentrations of total trichloro-compounds in urine(r=0.8212) and the concentrations of trichloroacetic acid in urine(r=0.7216). 3. The average trichloroethylene concentrations in the manual cleaning plants and that in the automatic cleaning plants were 40.1 ppm and 7.7 ppm, respectively. The difference between two groups was statistically significant. 4. The geometric mean of 49.6 ppm trichloroethylene concentration was resulted in the $185.4mg/{\ell}$ total trichloro-compounds in urine, and the 50 ppm trichloroethylene concentration was expected to produce $170.4{\pm}28.5mg/{\ell}$ total trichloro-compounds in urine. 5. With the geometric mean of 49.6 ppm trichloroethylene concentration, the corresponding geometric mean concentration of trichloroacetic acid in urine was $74.7mg/{\ell}$. In conclusion, the level of personal exposure to trichloroethylene concentration was significantly correlated with the concentrations of total trichloro-compounds and trichloroacetic acid in urine. Current biological screening value of $75mg/{\ell}$ for trichloroacetic acid in urine set by the Ministry of Labor was thought to be appropriate, and a biological screening value for total trichloro-compounds in urine should be set in the range of $170.4{\pm}28.5mg/{\ell}$ as a reference value for trichoroethylene exposure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.1
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• pp.38-47
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• 2016

Objectives: The objective of this study was to determine the exposure levels of forklift operators to diesel engine exhaust(DEE) using black carbon(BC), elemental carbon(EC), and nitrogen dioxide($NO_2$) as indicators. Methods: A total of eight forklift operators in six collection companies were assessed over a period of two months from July to September 2015. BC was measured using a real-time monitor and respirable EC samples were analyzed using the NIOSH method 5040. $NO_2$ samples were collected using a passive badge-type sampler. Results: The geometric mean of BC, EC and $NO_2$ were $3.1-19.1{\mu}g/m^3$, $2.1-23.8{\mu}g/m^3$, and 12.5-166.6 ppb at all companies. When forklifts were operating both outside and inside, BC concentrations increased 2.0-5.6 times. The highest increase was observed when forklifts were operating indoors. The increase in BC concentrations varied by company(company A: 2.0 times, B: 3.2 times, C: 5.6 times, D: 2.1 times, E: 5.1 times, F: 2.6 times). The geometric mean of BC, EC, and $NO_2$ for the forklift operators was $9.6{\mu}g/m^3$, $7.9{\mu}g/m^3$, and 48.9 ppb, respectively. The geometric mean of BC, EC, and $NO_2$ for manufacturing workers was $9.3{\mu}g/m^3$, $0.9{\mu}g/m^3$, and 85.2 ppb, respectively. The mean BC and EC exposure levels for the forklift operators were slightly higher than those for manufacturing workers, but $NO_2$ levels for manufacturing workers were higher than those for the forklift operators(p>0.05). Multiple regression analysis revealed that diesel exhaust emissions standard, forklift weight and forklift manufacturer were the most influential factors in determining worker exposure. Conclusions: In the DEE work environment, workers who perform tasks within the workplace as well as inside forklifts as operators are likely to be exposed to a lack of ventilation. Further study of forklift operators' exposure to DEE indicators should be conducted to include a wider range of occupational and environmental situations, such as collection procedures, seasonal situations, types of fuel used, and number of forklifts.

• Journal of Preventive Medicine and Public Health
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• v.29 no.4 s.55
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• pp.863-875
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• 1996

In order to prepare the fundamental data for the health promotion by assessing the exposure level of styrene, the author determined the concentration of mandelic acid and phenylglyoxylic acid in urine of 42 workers who were exposed to styrene by high performance liquid chromatography and surveyed 16 symptoms, by questionnaire and also tested neurobehavioral test(digit symbol, benton visual retention) in 2 FRP plants of Kyung Nam area from July to September, 1995. Control was sampled by age sex matching method. The concentration of styrene in air was determined by gas chromatography. The results were as follows; 1. Geometric mean concentration of styrene in air was 17.4ppm, geometric mean concentration of mandelic acid(MA) in urine were 404.3mg/g creatinine for exposure group, 46.4mg/g creatinine for control group, geometric mean concentration of phenylglyoxylic acid(PGA) in urine were 57.5mg/g creatinine for exposure group, 9.5mg/g creatinine for control group. Mean concentration of MA and PGA showed statistically significant difference between exposure group and control group(p<0.01). 2. Number of symptom were 2.9 for exposure group, 3.3 for control group, number of digit symbol were 24.1 for exposure group, 32.5 for control group, number of Benton visual retention test were 6.1 for exposure group, 6.0 for control group, respectively. As result of adjusting the education year, number of Benton visual retention test showed statistically significant difference between exposure group and control group(p<0.05). 3. Excellent correlation were observed between environmental styrene exposure and urinary MA(r=0.80), PGA(r=0.73), and MA+PGA(r=0.81).

• Journal of Biosystems Engineering
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• v.33 no.2
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• pp.101-105
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• 2008

Some physical properties of rapeseed such as geometric properties (linear dimensions, sphericity, seed volume, surface area) and gravimetric properties (the mass of one thousand seeds, bulk density) were analyzed at five levels of moisture content of 10.03, 14.91, 20.07, 25.06 and 30.12% (w.b.). The physical properties of rapeseed were evaluated as a function of seed moisture content. In the moisture range, when the moisture content increase, sphericity decreased from 0.946 to 0.927, and geometric mean diameter, seed volume and surface area increased from 2.17 to 2.31 mm, 5.58 to $6.88 \;mm^3$ and 14.76 to $16.77\;mm^2$ respectively. Mass of one thousand seeds increased from 5.04 to 6.46 g. Bulk density decreased from 579.3 to $549.2\;kg/m^3$ due to swelling of the seed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.584-590
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• 2015

Objectives: The purpose of this study was to evaluate quartz concentrations in airborne total and respirable dusts. Materials: Respirable dust samples were collected using a 10 mm aluminum cyclone equipped with a 37 mm$5{\mu}m$ pore size PVC filter. Total dust samples were collected with a three stage cassette from three work sections at earthwork sites located in the South Chungcheong-do Province area. Results: The geometric means of quartz concentrations were $0.008mg/m^3$ and $0.004mg/m^3$ in total dust and respirable dust, respectively. The geometric means of quartz contents analyzed by FTIR were 3.74% in total dust and 3.16% in respirable dust. The geometric mean of quartz concentrations and contents in secondary blasting operations were higher than those in other operations. Conclusions: Given that secondary blasting operations had higher quartz concentrations, there is a need to reduce respirable dust, such as through wet operations.