• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.131-138
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• 2014

Vibration measurement of rotating shafts by installing sensors such as accelerometers or displacement sensors is costly and dangerous in some cases. As an alternative method, vibration measurement using camera images has been researched because sensor installation is not needed and displacement of a rotating shaft can be directly evaluated. This paper also suggests the enhanced technique applicable to the measurement of vibration of a large-scale rotating shaft. The concurrent methods based on camera images use marks, which are hardly applicable to rotating shafts. The proposed method measures vibration without any marks by evaluating shape errors. The working principle of the method is described and verified by a series of experiments.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.271-276
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• 1999

미국을 비롯한 선진국들은 이미 휘발성 유기화합물(volatile organic compounds) 과 독성 중금속(toxic metals)을 비롯한 유해 대기오염물(hazardous air pollutants)에 대해 ATEOS (Airborne Toxic Element and Organic Species), TEAM(Total Exposure Assessment Measurement) 연구등의 대규모 연구를 통하여 인체에 미치는 영향이 가장 큰 물질군이 휘발성 유기화합물임을 밝혀낸 바 있다. (중략)

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.3
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• pp.271-277
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• 2019

Objectives: A 46-year-old woman who had worked on cleaning stainless steel containers with Initially unknown powders died from acute silicosis. To determine whether the acute silicosis was related to his work environment, we conducted exposure assessment the level of exposure to respirable crystalline silica(RCS) during cleaning stainless steel containers with unknown powders. Methods: The exposure assessment of RCS were undertaken according to the National Institute for Occupational Safety and Health(NIOSH) method 7500. The components of the unknown powder were analyzed using X-ray Diffraction. Results: The unknown powder was found to be natural diatomaceous earth, which contained 12% and 9% quartz and cristobalite, respectively, crystalline silica. In the case of cleaning stainless steel containers with diatomaceous earth powder, the primary measurement resulted in 1.3 times higher occupational exposure limit of MOEL(in sum of quartz and cristobalite concentration) and 3.9 times higher in secondary measurement. The workbench was equipped with a local exhaust system, but because there was no hood at the end of the duct, the wind speed at the opening of the duct was 12 m/sec, whereas the controlled wind speed at the working position was only 0.3 m/sec below the legal standard. Conclusions: There is an urgent need to install the hood, conduct safety and health education for employers and workers, and periodically monitoring and manage the working environment.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.259-262
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• 2003

Fabric hand is ultimately a subjective response to physical stimuli, but there are clearly practical advantage in the development and commercial trading of textile fabrics to be gained from the replacement of the traditional subjective tactile assessment by an objective measurement evaluation method. Moreover, the reliable objective measurement method for warp knitted fabrics have not developed yet, despite their increasing importance. (omitted)

• Journal of the Korean School Mathematics Society
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• v.25 no.3
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• pp.261-278
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• 2022

The purpose of this study is to develop an assessment to diagnose difficulties in learning mathematics and misconstructions that elementary students have. With thorough theoretical background and analysis of mathematics curriculum documents, we established learning trajectories for the following content areas in grades 3 to 6: number and operation, regularity, data and chance, geometry, and measurement. Then, the research team created the assessment items targeting a specific stage in the learning trajectories and including item options to identify possible misconceptions. Based on the unified validity theory, we reported the detailed procedure of the assessment development and the evidence for the content, substance, and structural validity of the assessment. We collected the data of 675 elementary students. Rasch measurement modeling was applied, and Cronbach's alpha was estimated. We considered how to report students' assessment results to teachers appropriately and immediately, which suggested important implications for supporting teaching and learning mathematics in elementary schools. We also suggested how to use the assessment developed in this study in online and distance learning environments due to the COVID-19 pandemic.

• BMB Reports
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• v.36 no.1
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• pp.1-11
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• 2003

The causative role of polycyclic aromatic hydrocarbons (PAH) in human carcinogenesis is undisputed. Measurements of PAH-DNA adduct levels in easily accessible white blood cells therefore represent useful early endpoints in exposure intervention of chemoprevention studies. The successful applicability of DNA adducts as early endpoints depends on several criteria:i.adduct levels in easily accessible surrogate tissues should reflect adduct levels in target-tissues, ii. toxicokinetics and the temporal relevance should be properly defined.iii. sources of inter- and intra-individual variability must be known and controllable, and finally iv. adduct analyses must have advantages as compared to other markers of PAH-exposure. In general, higher DNA adduct levels or a higher proportion of subjects with detectable DNA adduct levels were found in exposed individuals as compared with non-exposed subjects, but saturation may occur at high exposures. Furthermore, DNA adduct levels varied according to changes in exposure, for example smoking cessation resulted in lower DNA adduct levels and adduct levels paralleled seasonal variations of air-pollution. Intra-individual variation during continuous exposure was low over a short period of time (weeks), but varied significantly when longer time periods (months) were investigated. Inter-individual variation is currently only partly explained by genetic polymorphisms in genes involved in PAH-metabolism and deserves further investigation. DNA adduct measurement may have three advantages over traditional exposure assessment: i. they can smooth the extreme variability in exposure which is typical for environmental toxicants and may integrate exposure over a longer period of time. Therefore, DNA adduct assessment may reduce the monitoring effort. ii. Biological monitoring of DNA adducts accounts for all exposure routes. iii. DNA adducts may account for inter-individual differences in uptake, elimination, distribution, metabolism and repair amongst exposed individuals. In conclusion, there is now a sufficiently large scientific basis to justify the application of DNA adduct measurement as biomarkers in exposure assessment and intervention studies. Their use in risk-assessment, however, requires further investigation.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.5 s.164
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• pp.788-800
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• 2007

The purpose of this study was to develop a caregiver's uniform that is appropriate for nursing and to improve movement adaptability as well as having a pleasing appearance. Based on the results of preliminary study, I investigated the inconvenience and problems with the existing uniforms and made a sample uniform taking into consideration the design, the material, and the pattern. We carried out a sensory assessment and quantitative assessment in order to compare the sample uniform with existing uniforms. Following are the results of this research. The top is a short-sleeved blouse with a round neckline having no collar and with armpit gussets. The armpit gussets are semicircles and the inverted pleats in the back are an improvement designed for activity. The pants are long reaching to the ankles with elastic in the waist so that the waist measurement may be adjusted. The length of the pants can be adjusted with strings and the pants have a funnel-shaped pocket for adjustment of length. We used a mix of polyurethane and polyester for the outer cloth of the uniform in order to improve activity function and used $Coolever^{TM}$, the sanitary textile that absorbs moisture well and dries in a short time, for gussets in the armpits, which is the heavy sweat area. The appearance assessment and movement adaptability assessment were performed with 5 subjects and 9 experts. For the results of the assessment, the sample uniform was appraised to be better than the existing uniforms in every item of an appearance comparison assessment except for the neckline assessment by the experts. As for the assessment of movement appropriateness and wearing assessment, the same subjects were used for analysis. As the results of the assessment, the sample uniform was rated higher than the existing uniforms in movement adaptability and pleasing appearance.

• Journal of Environmental Impact Assessment
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• v.12 no.2
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• pp.87-98
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• 2003

The main purpose of this study is to propose the integrated assessment model for the rational and effective selection of proposed sites in National Trust (NT) and conserve the ruined natural environment by excessive land development. The results of this study are as follows; 1) The specialists thought that rare and endangered species were very important in plant and animal, in case of landscape and environment, naturality and water quality were too important. 2) In the result of the correlation measure on the indicator of assessment, 'erosion of soil'and 'air pollutant'was highly correlative. Secondly, 'suspended solids' and 'erosion of soil'was high correlation. 3) In the result of forming the factors into the integrated indicators, they were classified into conditional, stable, valuable and potential factors and the purpose of this formation is to evaluate proposed sites in NT objectively and rationally with organic assessment. 4) In the integrated assessment model, the degree of explanation was observed approximately 36.4% and the important factor was the conditional factor, but we have to consider all factors for the effective and objective assessment. Therefore we organically have to apply and use them for the assessment of proposed sites in NT. It turns out to offer raw data on the land conservation and carry out the role of the instrument of measurement. As for future directions, the follow are proposed: 1) adaptation of real proposed site, 2) verification of effect and problem, 3) practical survey for diverse types as mountain, coast and inland.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.22-31
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• 2019

The flammable liquid conductivity is an important factor in determining the generation of electrostatic in fire and explosion hazardous areas, so it is necessary to study the physical properties of flammable liquids. In particular, the relevant liquid conductivity in the process of handling flammable liquids in relation to the risk assessment and risk control in fire and explosion hazard areas, such as chemical plants, is classified as a main evaluation item according to the IEC standard, and it is necessary to have flammable liquid conductivity measuring devices and related data are required depending on the handling conditions of the material, such as temperature and mixing ratio for preventing the fire and explosion related to electrostatic. In addition, IEC 60079-32-2 [Explosive Atmospheres-Part 32-2 (Electrostatic hazards-Tests)] refers to the measuring device standard and the conductivity of a single substance. It was concluded that there is no measurement data according to the handling conditions such as mixing ratio of flammable liquid and temperature together with the use and measurement examples. We have developed the measurement reliability by improving the structure, material and measurement method of measuring device by referring to the IEC standard. We have developed a measurement device that is developed and manufactured by itself. The test results of flammable liquid conductivity measurement and the data of the NFPA 77 (Recommended Practice on Static Electricity) Annex B Table B.2 Static Electric Characteristic of Liquids were compared and verified by conducting the conductivity measurement of the flammable liquid handled in the fire and explosion hazardous place by using Measuring / Data Acquisition / Processing / PC Communication. It will contribute to the prevention of static electricity related disaster by taking preliminary measures for fire and explosion prevention by providing technical guidance for static electricity risk assessment and risk control through flammable liquid conductivity measurement experiment. In addition, based on the experimental results, it is possible to create a big data base by constructing electrostatic physical characteristic data of flammable liquids by process and material. Also, it is analyzed that it will contribute to the foundation composition for adding the specific information of conductivity of flammable liquid to the physical and chemical characteristics of MSDS.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.555-571
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• 2023

Due to South Korea's concentrated summer rainfall, constituting 70% of the annual total, landslides frequently occur during the rainy season, necessitating accurate prediction methods to mitigate associated damage. In this study, a reduced-scale and full-scale slope was configured using weathered granite soil to find the possibility of establishing measurement management criterias through landslide reproduction. The experiment focused on matric suction, analyzing changes in ground properties and failure patterns caused by rainfall infiltration. Subsequently, an unsaturated infinite slope stability analysis was conducted. By calculating the failure time when the safety factor falls below 1 for each experiment, landslide prediction was demonstrated to be possible, approximately 17 minutes prior for the reduction-scale experiment and 6.5 hours for the full-scale experiment. These findings provide useful data for establishing Korean soil slope measurement management criteria that consider the characteristics of weathered granite soil.