• Coupled systems mechanics
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• v.2 no.1
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• pp.85-110
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• 2013

Generally, mass concrete structural behavior is governed by the strain components. However, relevant guidelines in dam engineering evaluate the structural behavior of concrete dams using stress-based criteria. In the present study, strain-based criteria are proposed for the first time in a professional manner and their applicability in seismic failure evaluation of an arch dam are investigated. Numerical model of the dam is provided using NSAD-DRI finite element code and the foundation is modeled to be massed using infinite elements at its far-end boundaries. The coupled dam-reservoir-foundation system is solved in Lagrangian-Eulerian domain using Newmark-${\beta}$ time integration method. Seismic performance of the dam is investigated using parameters such as the demand-capacity ratio, the cumulative inelastic duration and the extension of the overstressed/overstrained areas. Real crack profile of the dam based on the damage mechanics approach is compared with those obtained from stress-based and strain-based approaches. It is found that using stress-based criteria leads to conservative results for arch action while seismic safety evaluation using the proposed strain-based criteria leads to conservative cantilever action.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.105-114
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• 2019

Recently, the paradigm of road policy has been focused on user safety. Recently, the number of road facility improvement project has been continuously increased but the economic feasibility (B/C ratio) is insufficient. Therefore, it is necessary to select a reasonable road improvement project through accurate and objective analysis of the road safety evaluation. In this study, to develop a new road safety evaluation method, data were collected based on the current road safety evaluation method for 75 routes including national roads and provincial ones. Based on the collected data, problems were analyzed and utilized as the basic factors of the new road safety evaluation method. Therefore, in this study, traffic accidents were reflected as a general evaluation item by weighing to solve these problems, and the evaluation items were added from experiences and ideas of the local public officials. For each evaluation item, a reasonable weight was determined through AHP (Analytic Hierarchy Process) questionnaire evaluation with highway experts. In addition, the safety index was determined based on the evaluation criteria for each evaluation item. The criteria for evaluating the danger zone are determined by the overall safety index. Finally, the criteria for selection of road improvement projects based on the overall risk level were derived.

• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.59-66
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• 2012

Steel industry in Korea is a key national industry that has led economic growth for a long time. And accidents occurred from a variety of causes has endlessly made as much as remarkable achievements of steel industry. It is a fact that research achievements of disaster prevention in steel industry has not been significantly, compared to production technique achievements. And the level of interest on safety management in the steel industry is conspicuously low. Although support activity for a various safety management are provided reasonably to prevent disasters occurring with subcontractors. A method capable of quantitative evaluation, applied to subcontractors in most business places are relatively rare except parent firms-leading places. This study is to make and show safety management activities to purcue in advance in conjunction with a parent firm through development of a more systematic and quantitative evaluation model for disaster prevention with steel industry subcontractors, and to contribute to disaster prevention in domestic steel industry through advanced safety management method, by applying a proposed evaluation model of safety management activities as subcontractors in steel industry.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.288-296
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• 2009

We conducted validation for asbestos quality control (QC) samples made by the developed method which was presented in our published paper. The main results of the validation study are as follows. The pooled coefficient variations of analytical results in three different concentrations (low, medium, and high concentration) for amosite and chrysotile were less than 20 %, which met the sample homogenicity criteria of NIOSH. Also we confirmed the homogenicity of asbestos samples by using the relocatable field slide. To evaluate the field applicability of the developed asbestos QC samples, the field validation was performed with four proficient asbestos analysts by using the statistical methods of AIHA asbestos PAT program. All analytical results from four asbestos analysts were located in the acceptable range.

• Safety and Health at Work
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• v.12 no.1
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• pp.136-138
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• 2021

Coronavirus disease 2019 (COVID-19), which is a newly emerging infectious disease worldwide, can be categorized as an occupational disease, because employees, particularly in the healthcare system, can be infected at the workplace. As of December 15, 2020, we summarized the occupational safety and health practices in selected countries on the recognition of COVID-19 as one of the occupational risks. The situation has differed among countries, including the recognition status and whether a specific regulation existed. International organizations, namely the International Labour Organization, World Health Organization, and European Union, should plan and conduct studies on the work-relatedness of COVID-19, propose criteria for recognition, and add the infection to the occupational disease list to provide a basis for specific country regulations. Stakeholders should also act to adjust country-level legislation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.200-208
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• 2012

Objectives: This study investigated the performance of three separate units of a portable photoionization detector (PID, ppb-RAE 3000) for measuring volatile organic compounds (VOCs) in a laboratory. Methods: A laboratory evaluation of the accuracy, precision, and inter-instrumental variance of three separate units of a portable PID (ppb-RAE 3000) was performed. The evaluation was based on the preparation of a test air sample of known toluene or ethylacetate concentration in a Tedlar$^{(R)}$ bag. The test air sample was monitored and data were logged consecutively by the three PIDs. A certified gas of 50 ppm toluene was also monitored during the test to ensure the reliability of the generated test air sample. Four different concentrations ranging from 0.1 to 2 TLV were used and a series of five measurements for each concentration level was performed. The accuracy was evaluated using National Institute for Occupational Safety and Health (NIOSH) criteria. Results: The results from the oldest ppb-RAE3000 unit among the three test units generally fell outside the NIOSH recommended accuracy criteria of ${\pm}25%$, whereas the other two units produced results which were acceptable at, or greater than, 25 ppm of toluene, or 0.5 TLV. These units also met the NIOSH criteria for some ethylacetate measurements but the results were not consistent. Conclusions: Considering the inconsistent performance of these ppb-RAE 3000 units, this device may not be appropriate for use as an alternative to the standard measurement methods. However, it can serve good survey instruments to identify exposure sources or concentration profiles. For all applications, the ppb-RAE 3000 should be used with frequent calibration checks, additional validation using a reference material, and careful maintenance.

• Journal of Environmental Health Sciences
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• v.20 no.1
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• pp.54-61
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• 1994

This study was carried out to investigate the degree of contamination in private-drinking water supply (PDWS) and simple-piped water supply (SPWS), and to compare of water quality between them for 3 years from 1990 to 1992. The results of the study were as follows: 1. Private-drinking water supply (PDWS) (1) Field-Site (ㄱ) The items which were very significantly over the criteria (p<0.01), were temp., pH, NO-N, standard plate count (S.P.C.) and Coliform. (ㄴ) No. of households which were over the criteria, were 11.2~51.7% in temp., pH, NH$_3$-N and NO$_2$-N, and 83.1~93.3% in NO-N, S.P.C. and Coliform. (2) Moutain-Site (ㄱ) The items which were over the criteria, were NO$_2$-N (p<0.05), S.P.C. (p<0.01) and Coliform (p<0.01). (ㄴ) No. of households which were over the criteria, were 33.6 ~ 75.6% in NO$_2$-N, S.P.C. and Coliform. (3) No. of households which were fit to the criteria of all items, were 9.0% in field-site and 14.1% in mountain-site. 2. Simple-piped water supply (SPWS) (1) The items which were very significantly over the critera (p<0.01), were standard plate count (S.P.C.) and Coliform. (2) The water qualities of adjacent and remote samples were better than those of source samples. (3) Residual chloride was not detected in any sample. In conclusion, rural community requires to be continually performed the policy of safety drinking water supply, and to be devised an epoch-making counterplan for the level-up of simple-piped water supply (SPWS), espically on the method of disinfection.

• Journal of Environmental Health Sciences
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• v.40 no.3
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• pp.187-203
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• 2014

Objectives: As the demand to deal with pathogens in domestic research institutions has expanded and biological accidents have increased, the need for systematic biosafety management in infectious disease laboratories has grown. According to international standards, risk assessment (RA) is required for biosafety management. However, RA criteria have not been clearly established in Korea, so to this end I have attempted to determine RA criteria meeting international levels Methods: In order to provide RA criteria for application, I analyzed the RA criteria in use in the U.S., Europe and at international organizations. In order to ensure the public nature of the RA criteria, I constructed the research model through modified management consulting methodology reflecting the model of Radnor and O'Mahoney. Results: According to the results of the study, existing laboratory biosafety regulations were comparable to domestic laboratory safety laws. Existing laboratory biosafety standards that are designed around risk factors were found to be insufficient. An RA case to be carried out in infectious disease laboratories at the National Institute of Health of KCDC was identified. Conclusion: To establish a systematic risk management system meeting international standards, it was necessary first to harmonize the systems of national and international standards. In addition, in order to provide specific biosafety management on-site, I recognized a need for methodology and planning strategies to discover biosafety management so that it can be carried out as required through the RA of individual laboratories.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1646-1655
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• 2015

Korean government has issued the ratings standard for disease control of aquaculture farms according to the Aquatic Life Disease Control Act in 2008. There are five rating criteria within the enforcement regulations; period of disease free, performance of disinfection, environmental and hygienic management, keeping record of trade and sales, completion of education for disease control. There are no application has been applied on the basis of the rating criteria so far because detailed subcriteria and scoring indicators has not established for assessment process. In order to apply the ratings standard for disease control, we set up the subcriteria and new scoring for rating disease control level based on legal criteria in this study. This study was conducted on 90 targeted olive flounder farms in Jeju. The result of disease control level assessment on olive flounder aquaculture farms show the overall average of Jeju-do was 72.9 points and differed depending on the district; 74.7 in Jeju-si and 71.1 in Seogwipo-si, respectively. The Spearman correlation of each evaluation index show the disease control level score was correlated highly with the performance of disinfection(R=0.715, p<0.01), and environmental and hygienic management(R=0.661, p<0.01). The result of correlation analysis show that there is the highest correlation between the aquaculture farm status and the total mortality(R= -0.618, p<0.01). The reliability of the results are considered to be accurate in the Cronbach's alpha value of 0.727.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.101-119
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• 2018

In this study, we analyzed long-term measurements and air quality simulation results of four criteria air pollutants ($PM_{10}$, $O_3$, $NO_2$, and $SO_2$) for 10 years, from 2006 to 2015, with emphasis on trends of annual variabilities. With the observation data, we conducted spatial interpolation using the Kriging method to estimate spatial distribution of pollutant concentrations. We also performed air quality simulations using the CMAQ model to consider the nonlinearity of the secondary air pollutants such as $O_3$ and the influence of long-range transport. In addition, these simulations are used to deduce the effect of long-term meteorological variations on trends of air quality changes because we fixed the emissions inventory while changing meteorological inputs. The nation-wide inter-annual variability of modeled $PM_{10}$ concentrations was $-0.11{\mu}g/m^3/yr$, while that of observed concentrations was $-0.84{\mu}g/m^3/yr$. For the Seoul Metropolitan Area, the inter-annual variability of observed $PM_{10}$ concentrations was $-1.64{\mu}g/m^3/yr$ that is two times rapid improvement compared to other regions. On the other hand, the inter-annual variability of observed $O_3$ concentrations is 0.62 ppb/yr which is larger than the simulated result of 0.13 ppb/yr. Magnitudes of differences between the modeled and observed inter-annual variabilities indicated that decreasing trend of $PM_{10}$ and increasing trend of $O_3$ are more influenced by emissions and oxidation states than meteorological conditions. We also found similar patterns in $NO_2$. However, $NO_2$ trends showed greater regional and seasonal differences than other pollutants. The analytic approach used in this study can be applicable to estimate changes in factors determining air quality such as emissions, weather, and surrounding conditions over a long term. Then analysis results can be used as important data for air quality management planning and evaluation of the chronic impact of air quality.