• Journal of Environmental Health Sciences
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• v.22 no.2
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• pp.43-57
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• 1996

To characterize worker's exposure to glass fibers, to find the correlation between airborne total dust concentrations and fiber concentrations and to recommend an appropriate evaluation method for worker's exposure to fibrous dusts in glass wool industry, we carried out this study. Average respirable fiber levels at five factories were 0.013-0.056 f/cc, and fairly below the OSHA PEL, 1 f/cc. A factory showed the lowest airborne fiber level, 0.013 f/cc, which was different significantly from those of other factories of which average fiber concentration was 0.046 f/cc. The cutting and grinding operations of insulation products resulted in higher airborne fiber cocentrations than any other processes(p<0.05). To characterize airborne fiber dimension, fiber length and diamter were determined using phase contrast microscope. The geometric means of airborne fiber lengths were $42-105 \mu m$. One factory had airborne fibers whose length distribution(GM = $105 \mu m$) was different from those of other factories(GM = $42-50 \mu m$). The percentages of respirable fibers less thinner than 3 gm were 38.9-90.9% at four factories, and two factories of them had the higher percentages than others. The findings explain for variation of airborne fiber diameters between factories. On the other hand, between the processes were the difference of fiber-length distributions observed. The cutting and grinding operations showed shorter fiber-length distributions than the fiber forming one. However, fiber-diameter distributions or respirable fiber contents were similar in all processes. The airborne fiber concentrations and the dust concentrations had relatively weak correlation(r=0.25), thus number of fibers couldn't be expected reliably from dust amount. Fiber count is appropriate for assessing accurate exposures and health effects caused by fibrous dusts including glass fibers. Ministry of Labor have established occupational exposure limit to glass fibers as nuisiance dust, but should establish it on the basis of respirable fiber concentration to provide adequate protection for worker's health

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.3
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• pp.257-267
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• 2005

The real-time operating system(RTOS) simulator, one of the tools provided by RTOS development environment, allows users to develop and debug application programs even before the target hardware is ready. Thus, most of commercial RTOS development environments provide with RTOS simulator for the purpose. But they are implemented to simulate only functional aspects on a host system, so that it is not possible to estimate execution time of application programs on the target hardware. Since the real-time system has to complete program executions in predetermined time, the RTOS simulator that can estimate the execution time is yeW useful in the development phase. In this study, we develop a machine instruction-level RTOS simulator that is able to estimate execution time of application programs on a target hardware, and prove its functionality and accuracy by using test .programs.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.4
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• pp.303-309
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• 2008

The reduction of risk within the workplace has long been focus of attention both through industry initiatives and legislation. Exposure matrices according to industries and processes treated DMF (N,N-Dimethylformamide) were constructed based on KOSHA (Korean Occupational Safety and Health Agency)'s 2005 exposure database which were gathered from Korean agencies of workplace hazards evaluation for business place. These exposure matrices were assessed by danger value (DV) that was calculated from combination of hazard rating, duration of use rating, and risk probability rating of exposure to chemical hazardous agents in accordance with Hallmark Risk Assessment Tool. The results of risk assessment is divided four kinds of control bands which were related with control measures. The applicability of risk assessment using exposure matrices was performed by field study and survey for high matrices group. This study found that more attentions should be paid to two industries, manufacture of sewn wearing apparel and manufacture of textiles, among 19 industries, and to 3 processes, coating, processing & mixing, and lab, among 80 processes because those were regarded as having the highest risk.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.2
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• pp.201-207
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• 2014

Objectives: Flow rate stability is very important for obtaining reliable measurements. However there is no easily used method for checking whether the flow rate set at the initial stage is sustained during sampling. The purpose of this study was to develop a method to evaluate the flow rate performance of gas sampling pumps with adsorbents commonly used to sample gases. Materials and methods: We tested the back pressure of gas sampling pumps commonly used in Korea with adsorbents such as charcoal and silica tubes and attempted to discover the combination conditions of adsorbents in accordance with back pressure required by ISO standard 13137. Results: We found the combination of sampling adsorbents to be applicable to the pressure drop required by the ISO standard for evaluating flow rate stability under increasing pressure drop and long term (eight-hour) performance. Conclusions: This evaluation method of using a sampling media matrix for checking flow rate stability as proposed by this study could be a highly useful tool for determining the reliability of the performance pumps before sampling.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.2
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• pp.193-200
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• 2014

Objectives: To develop domestic charcoal tubes with good adsorption capacity, breakthrough experiments were performed on four types of activated charcoal. Materials: The adsorption capacity and the adsorption rate were determined using a modified Wheeler equation after the breakthrough experiment. For four types of charcoal (J, K, S and SKC Inc. 226-01), 100 mg were used in the breakthrough experiment. The test was done on benzene, toluene, n-hexane, and acetone in a dynamic chamber. Results: K charcoal had the greatest surface area and the highest micropore volume. J charcoal had a similar surface area and micropore volume to SKC charcoal. S charcoal had the lowest surface area and micropore volume. J charcoal had the highest adsorption capacity at 101, 252 and 609 ppm of benzene. The gap in benzene adsorption capacity among the types of charcoal was the least at 609 ppm and the greatest at 101 ppm. J charcoal showed the highest adsorption capacity at 54, 106, 228 and 508 ppm of toluene. J charcoal and SKC charcoal had a similar adsorption capacity for acetone. J charcoal had the highest adsorption capacity for n-hexane. In the experiment featuring 10% breakthrough volume, 10% breakthrough occurred at 18 liters at $2065.9mg/m^3$ for J charcoal and at 20 liters at $1771.2mg/m^3$ for K charcoal. It was difficult to judge adsorption capacity by surface area and micropore volume of charcoal. J charcoal, which was similar to SKC charcoal in surface area and micropore volume, showed good adsorption capacity at common workplace concentrations. Conclusions: The adsorption capacity of J and K charcoal was superior compared with SKC charcoal. J and K charcoal can be considered appropriate for use as sampling media based on this result.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.123-136
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• 2013

Objectives: This paper was prepapred to report airborne asbestos fiber concentrations in asbestos textile, brake-lining, commutator, and building materials manufacturing industries, and some other asbestos related industries in Korea from 1994 to 2006. Methods: Airborne asbestos data that have been sampled and analyzed in the above industries during 1994-2006 were collected. These data were reviewed to scrutinize the qualified data based on the records such as sampling and analyzed method and quality control procedures. All asbestos data were generated using the National Institute for Occupational Safety & Health (NIOSH) Method 7400. Results: Average concentration of asbestos fiber was 2.14 fibers/cc(0.02-15.6 fibers/cc) in the asbestos textile industry, 0.26 fibers/cc(0.01-1.01 fibers/cc) in the building-materials industry, 0.15 fibers/cc(0.01-0.93 fibers/cc) in the brake-lining manufacturing industry, and 0.14 fibers/cc(0.03-1.36 fibers/cc) in the commutator producing industry. For these industries, the percentage of samples of which asbestos fiber concentrations above the limit of exposure(0.1 fibers/cc) was 97.6% in the asbestos textile industry, 62.3% in the building-materials industry, 53.5% in the brake-lining manufacturing industry, and 34.3% in the commutator producing industry. Asbestos fiber concentration was below the limit of exposure in the gasket producing, petrochemistry, musical instrument producing industries, and the brake-lining exchange operations. Conclusions: Airborne asbestos fiber level in the asbestos textile, brake-lining producing, commutator and building-material producing industries was above the limit of exposure, but in the gasket producing, petrochemistry, musical instrument producing industries and the brake-lining exchange operations were below the limit of exposure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.108-113
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• 2013

Objectives: Although several cases of lung diseases caused by indium have been reported in Japan, the United States and China, South Korea, which is estimated to have been the world's largest consumer of indium, has not yet established a criteria for the diagnosis of lung diseases caused by indium exposure. In this study, we tried to determine the applicability of the Krebs von den lungen-6, which has been widely recognized for its use with interstitial lung disease in Japan, as a biological exposure index for indium. Methods: Methods: The analysis of indium in serum was conducted by inductively coupled plasma mass spectrometry and the analysis of KL-6 in serum was carried out using enzyme-linked immunosorbent assay kit. Results: The indium levels in serum were distributed from below the detection limit to a peak of $125.78{\mu}g/L$, and the values of the KL-6 were distributed from 104.5 U/mL to 2162.2 U/mL. The serum indium and KL-6 showed good correlation ($R^2$=0.389,pfortrend=0.000) and smoking did not affect the KL-6. Conclusions: The usefulness of KL-6 as a specific biomarker for interstitial lung disease has been recognized. In addition, it is expected that effective prevention of health problems can be achieved by determining the lung-damage progress at an early stage according to individual susceptibility.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.50-57
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• 2020

Objectives: Methyl bromide is a highly toxic substance that can cause systemic poisoning, neurotoxicity, pulmonary edema. Methyl bromide is a widespread fumigation agent used for import and export quarantine, but there is little data on exposure assessment of workers participating in such fumigation. Therefore, this study aims to investigate the exposure level of methyl bromide among workers and the concentration distribution of methyl bromide in the workplace during fumigation. Methods: For this study, one wood tent and one container fumigation area in Pusan, and one wood tent fumigation area in Incheon were investigated over three months from June 2001. Results: Methyl bromide exposure levels for container fumigation workers were from undetected to 1.86 ppm and from undetected to 2.28 ppm for tent fumigation workers as an 8 hr TWA. After opening the container door, the methyl bromide concentration in the container decreased rapidly over time, but the concentration remained over 1 ppm even after about one hour. The concentrations around the tent during its removal were highly affected by wind, but were detected in a range from undetected to 11.97 ppm. Conclusions: This study confirmed that both container and tent fumigation caused workers to exceed the exposure limit of 1 ppm as an 8 hour TWA. In particular, it could be confirmed that a situation exists in which the worker may be exposed to high concentrations of methyl bromide when opening the container or removing the tent due to the nature of the work. Therefore, it is very important to improve working methods and to wear appropriate personal protective equipment.

• Journal of KIISE:Software and Applications
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• v.33 no.4
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• pp.378-387
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• 2006

A programming model for ubiquitous sensor network (USN) applications based on Nano-Qplus is proposed. USN applications mean programs of nodes which are components of sensor network such as sensor, router, sink and actuator. Developers can automatically generate programs of USN applications by setting attributes values of nodes using a script after they model a sensor network. A script for setting attributes values of a node is proposed in this paper. The algorithm of automatic code generation is also described. Developers can easily implement USN applications even if they do not know details of low-level communication, data sharing, and collective operations because the applications are automatically generated from a script. They set only attributes values of nodes using the script. Efforts for USN applications development also are reduced because of automatic code generation. Furthermore, developers can correct errors of applications in the early stage of development through ear]y test based on rapid code generation.

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.240-246
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• 2013

Airtouch technology to integrate the system in the way of information delivery devices, touch screen DID this study is to develop new ways of information delivery systems. Airtouch technology to design and implement a system that can be utilized to view the college campus announcements, education, information, and employment information, and store the remote operation and sharing content, the development of cloud services to sync content via smart technology implementation fusion DID systemto develop. Packs USB interface kinek because you may be used in connection with the information appliances, and low-cost product by leveraging the Kinect sensor, Airtouch technology implementation. Types of input devices paper Airtouch technology systems, the user's hand gestures alone can interact with information appliances, smart fusion system developed by DID by tracking the user's hand movements to manipulate the mouse pointer, and information through the user's hand gestures to command the unit so that you can make. Airtouch technology smart fusion DID system technology utilizing a ripple effect on other industries, such as the online education industry, advertising, information industry increases. Also, replace the existing interface device with the versatility of a wide range of technologies, usability is an infinite expansion.