• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.854-860
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• 2014

Workers engaged in car inspection works have been exposed to many occupational hazards including noise, particulate matter, and volatile organic substances. Noise-induced hearing loss(NIHL) is one of the leading health hazards among Korean workers. The aim of this study is to evaluate the noise levels in several car inspection shops by introducing the evaluation methods of KMOEL/OSHA and ACGIH. Six sites in central area of Korea were selected to monitor the noise levels of workers by personal and area sampling methods for two consecutive days in spring, summer, fall and winter seasons. Dosimeters have been used for this noise monitoring program. Obtained noise levels by the evaluation method according to KMOEL/OSHA are the range of 50.2~88.2 dB(A), these are lower than KOEL/OSHA standards level of 90 dB(A). But highest noise by ACGIH's evaluation methodology is recorded 92.3 dB(A) and is greater than NIHL standard level of 85 dB(A). So that many workers may be exposed to the dangerous noise environment. The higher the car inspection loads daily, the higher the noise levels in the sites. Seasonal fluctuation of noise levels at the process might give monitoring results with high variations. Area noise levels showed higher than those of personal sampling, which illustrate some high noise spots in the car inspection areas.

• Journal of Bio-Environment Control
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• v.31 no.2
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• pp.79-89
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• 2022

With the wide use of greenhouses, the working hours have been increasing inside the greenhouse for workers. In the closed ventilated greenhouse, the internal environment has less affected to external weather during making a suitable temperature for crop growth. Greenhouse workers are exposed to organic dust including soil dust, pollen, pesticide residues, microorganisms during tillage process, soil grading, fertilizing, and harvesting operations. Therefore, the health status and working environment exposed to workers should be considered inside the greenhouse. It is necessary to secure basic data on particulate matter (PM) concentrations in order to set up dust reduction and health safety plans. To understand the PM concentration of working environment in greenhouse, the PM concnentrations were monitored in the cut-rose and Hallabong greenhouses in terms of PM size, working type, and working period. Compare to no-work (move) period, a significant increase in PM concentration was found during tillage operation in Hallabong greenhouse by 4.94 times on TSP (total suspended particle), 2.71 times on PM-10 (particle size of 10 ㎛ or larger), and 1.53 times on PM-2.5, respectively. During pruning operation in cut-rose greenhouse, TSP concentration was 7.4 times higher and PM-10 concentration was 3.2 times higher than during no-work period. As a result of analysis of PM contribution ratio by particle sizes, it was shown that PM-10 constitute the largest percentage. There was a significant difference in the PM concentration between work and no-work periods, and the concentration of PM during work was significant higher (p < 0.001). It was found that workers were generally exposed to a high level of dust concentration from 2.5 ㎛ to 35.15 ㎛ during tillage operation.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.303-314
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• 2004

Objectives: This study was carried out to assess exposure levels of organic dusts and ammonia in poultry farms in Korea. Methods: A total of six poultry farms were investigated. The farms were located in Namwon, Chonlabuk-do and in Kae-San, Chungchongbuk-do. This study consisted of a questionnaire and measuring organic dusts and ammonia. The questionnaire included the characteristics of the farms, work patterns and the tasks of the poultry farms. Results and Conclusions: The farmers raised the chickens 45 times a year and the average number of years in the poultry farm were eight years ranging from 2 to 12 years. They worked for seven days per week and the average hours spent caring the chickens are 6.3 hours per day. The duration of staying in the confinement buildings was 3.3 hours per day. The work time in summer was longest. The feed and the water supply systems were automatic and the control of ventilation windows used "winch curtain" was semiautomatic. They used mechanical ventilation system in winter and used dilution ventilation system in the other seasons. The geometric mean concentration of total and respirable dust sampled in the poultry confinement buildings was 4.0 mg/$m^3$and 0.9 mg/$m^3$ respectively. The ratio of respirable to total dusts range from 9 to 49 percent. There was no sample exceeding the criteria 10 mg/$m^3$ for total dust and 3 mg/$m^3$ for respirable dust in farms. The criteria have been recommended by Korean Ministry of Labor and American Conference of Governmental Industrial Hygienist. The personal respirable dusts measured during a circle work averaged geometric mean concentration 1.4 mg/$m^3$ Two personal samples were exceeded the threshold 3 mg/$m^3$. There was a positive relation between an index and the personal samples of respirable dusts($R^2$=0.98). The index is calculated by multipling the total number of chickens in the farm by the age of the chickens and then dividing by the volume of the confinement building. The geometric mean concentration of area and personal ammonia samples was 23.3 ppm and 22.2 ppm, respectively. Some of the ammonia samples, both area and personal samples, exceeded the short term exposure limit value 35 ppm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.451-457
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• 2020

Format recognition and OCR techniques are widely used as methods for detecting and protecting personal information from electronic documents. However, due to the poor recognition rate of the OCR engine, personal information cannot be detected or false positives commonly occur. It also takes a long time to analyze a large amount of electronic documents. In this paper, we propose a method to improve the speed of image analysis of electronic documents, character recognition rate of the OCR engine, and detection rate of personal information by improving the existing method. The analysis speed was increased using the format recognition method while the analysis speed and character recognition rate of the OCR engine was improved by image correction. An algorithm for analyzing personal information from images was proposed to increase the reconnaissance rate of personal information. Through the experiments, 1755 image format recognition samples were analyzed in an average time of 0.24 seconds, which was 0.5 seconds higher than the conventional PAID system format recognition method, and the image recognition rate was 99%. The proposed method in this paper can be used in various fields such as public, telecommunications, finance, tourism, and security as a system to protect personal information in electronic documents.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.728-733
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• 2007

Presence and distribution of bacteria and fungi in inner compartment of PCs(Personal Computers) were investigated. Samples for the analysis were collected from inside of PCs which had been used in various facilities including public computer facilities, laboratories and computer training rooms of a university. Total number of PC examined in this study was 51 each. When the total CFU(colony forming unit) of the inner compartment of the PCs was measured, the bacterial count was found to be dependent on the operation time(total running time) of PCs. When the distribution of bacteria in the inner compartment of PCs was estimated, CPU(Central Processing Unit) cooling fan area showed the highest bacterial concentration(average 605 $CFU/cm^2$). In the case of the fungi, various opportunistic pathogens including Aspergillus sp. and Penicillium sp. were isolated and identified in the inner compartment of PCs. And the average of bacterial number in the dust collected from the PCs was 212 CFU/mg. These results indicated that handling of PC might have a risk of infection by the microorganism.

• Analytical Science and Technology
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• v.23 no.5
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• pp.477-484
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• 2010

Personal care products are a diverse group of synthetic organic chemicals such as antimicrobial compounds, UV filters and organo-phosphate flame retardants and derived from individual usages of soaps, toothpaste and cosmetics. It has been detected in municipal sewage effluent and various environmental samples such as surface water, marine, soil, sediment and aquatic biota in many countries. The occurrence of personal care products in environmental samples could negatively impact the health of the ecosystem and humans, due to persistent, long-term chronic exposure of aquatic organisms. In this study, fifteen personal care products in aquatic environmental samples were determined by gas chromatography-mass spectrometry (GC-MS) with liquidliquid extraction (LLE). Method detection limits were in the range of $0.004\sim0.273\;{\mu}g/L$. Two compounds (TCEP, TCPP) were detected in surface waters and seven compounds (triclosan, 4-MBC, EHMC, BP-3, TCEP, TPP, TBEP) were detected in sewage treatment plants (STP) influents or effluents.

• Analytical Science and Technology
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• v.26 no.2
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• pp.125-134
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• 2013

This study was demonstrated to estimate the measurement uncertainty of 23 multiple-component amino acids from beef bone extract by high performance liquid chromatography (HPLC). The sources of measurement uncertainty (i.e. sample weight, final volume, standard weight, purity, standard solution, calibration curve, recovery and repeatability) in associated with the analysis of amino acids were evaluated. The estimation of uncertainty obtained on the GUM (Guide to the expression of uncertainty in measurement) and EURACHEM document with mathematical calculation and statistical analysis. The content of total amino acids from beef bone extract was 36.18 g/100 g and the expanded uncertainty by multiplying coverage factor (k, 2.05~2.36) was 3.81 g/100 g at a 95% confidence level. The major contributors to the measurement uncertainty were identified in the order of recovery and repeatability (25.2%), sample pretreatment (24.5%), calibration-curve (24.0%) and weight of the reference material (10.4%). Therefore, more careful experiments are required in these steps to reduce uncertainties of amino acids analysis with a better personal proficiency improvement.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.28-34
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• 2015

This study is to investigate microbiological hazards which can be used as fundamental data to adequately control leeks hazards and develop leeks GAP model for those who want to get GAP system. The microbiological investigations on cultivation environments (soil and water), crops (leeks), personal hygiene (workers' hands, clothes and gloves) and working tools (boxes) have been conducted for one year, so the period was classified under non-cultivation, cultivation, and post harvest. Total bacteria was detected from soil (4.0~6.7 log CFU/g), leeks (4.6~5.1 log CFU/g), hands (ND~3.3 log CFU/hand) and gloves ($ND{\sim}5.4\;log\;CFU/cm^2$) while nothing was detected from the other samples. The coliform contamination of leeks (4.8~5.0 log CFU/g) was more high than that of soil (3.9~4.2 log CFU/g). In case of foodborne pathogens, only B. cereus was detected at the level of 0.5~4.6 log CFU/g (or hand, $100cm^2$). Fungi was observed at the level of 2.1~3.8 log CFU/g (or hand, $100cm^2$) excepting water and some working tools. These results demonstrate that the contamination of leeks is comparatively higher than that of soil sample. The reason may be the cross-contamination by biological hazards presenting on soil. Therefore, it is necessary to properly control soil and fertilizer for safety against biological hazards.

• Analytical Science and Technology
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• v.18 no.4
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• pp.362-367
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• 2005

The human mitochondrial genome (mtDNA) has been an important tool in the field of forensic investigations. Within the entire mtDNA molecule, the non-coding control region which is approximately 1,100 bp including hypervariable region I and II (HV1 and HV2) is widely studied because it is highly polymorphic and useful for human identification purposes. In this study, 360 unrelated Koreans were analyzed in HV1. The number of polymorphic sites and genetic lineage were 124 and 210, respectively. The most prevalent substitution was C-T and 75.8% of DNA showed C-T substitution at 16223. There were 20 kinds of polymorphism between 16180 and 16193 including insertion and deletion. The most frequent haplotype was [16223T, 16362C] representing 5%. Approximately 25.9% of DNA showed the same haplotype in at least two samples. The gene diversity was calculated to 0.996 and the probability of two unrelated perosons having the same haplotype was determined to 0.7%.

• Journal of the Korean Chemical Society
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• v.47 no.4
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• pp.401-411
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• 2003

One of the most important characteristics in the seventh educational course is an enforcement of differentiated level curriculum. Therefore, development of various different level educational subjects is needed. A new chromatographic experimental kit which is helpful for middle school students to understand chromatographic principles is needed to correct some mistakes of chromatographic part within the 6th educational course's middle school textbook. In this research, a new thin layer chromatography(TLC) experimental kit for middle school students are developed by using acid-base indicator as samples and ethyl alcohol, ethylacetate, hexane as eluents. The kit is applied to two kinds of middle school student groups(general group & genius group) and two kinds of teacher groups(science teacher & non-science teacher) and an efficacy of the new chromatographic kits are evaluated through making up some questions.