• Communications of the Korean Mathematical Society
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• v.20 no.3
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• pp.611-621
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• 2005

This paper introduces an ID based authenticated two pass key agreement protocol of Smart[4] which used the Weil pairing. We propose other an ID based authenticated two pass key agreement protocol which using the Tate Pairing. We will compare protocol of Smart with this protocol.

• Korea Journal of Hospital Management
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• v.25 no.4
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• pp.1-12
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• 2020

During the COVID-19 pandemic, most of the western countries with advanced medical technology failed to contain coronavirus. This fact triggered our research question of what factors influence the clinical outcomes like infection rates and case mortality rates. This study aims to identify the determinants of COVID-19 related infection rates and case mortality rates. We considered three sets of independent variables: 1) socio-demographic characteristics; 2) cultural characteristics; 3) healthcare system characteristics. For the analysis, we created an international dataset from diverse sources like World Bank, Worldometers, Hofstede Insight, GHS index etc. The COVID-19 related statistics were retrieved from Aug. 1. Total cases are from 95 countries. We used hierarchical regression method to examine the linear relationship among variables. We found that obesity, uncertainty avoidance, hospital beds per 1,000 made a significant influence on the standardized COVID-19 infection rates. The countries with higher BMI score or higher uncertainty avoidance showed higher infection rates. The standardized COVID-19 infection rates were inversely related to hospital beds per 1,000. In the analysis on the standardized COVID-19 case mortality rates, we found that two cultural characteristics(e.g., individualism, uncertainty avoidance) showed statistically significant influence on the case mortality rates. The healthcare system characteristics did not show any statistically significant relationship with the case mortality rates. The cultural characteristics turn out to be significant factors influencing the clinical outcomes during COVID-19 pandemic. The results imply that the persuasive communication is important to trigger the public commitment to follow preventive measures. The strategy to keep the hospital surge capacity needs to be developed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.1
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• pp.73-81
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• 2012

Object: The aim of this study is to suggest a list of priority chemicals for the Hazard & Risk Evaluation of Chemicals (HREC) controlled by the Industrial Safety and Health Act (ISHA). Method: Screening assessment was done for 642 chemicals whose exposure threshold limit values were set by the Ministry of Employment and Labor (MOEL). Hazard data were collected from Korea Occupational Safety & Health Agency (KOSHA) and/or other toxicity database. Exposure data were obtained from KOSHA internal database. The hazard and exposure scores of chemicals were listed by order of priority in accordance with GHS classification and exposure index data. Result: From the result of screening risk assessment for 642 chemicals, we extracted a list of 13 priority chemicals for HREC performed by the ISHA. A priority list of 27 chemicals which have carcinogen, mutagen and/or reproductive toxicity but not controlled by the ISHA was suggested for additional evaluation as "chemicals for special management".

• Journal of the Korean Institute of Gas
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• v.25 no.1
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• pp.40-47
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• 2021

In this study, hazards of decomposition and explosion for tert-butylperoxymaleate(TBPM), an organic peroxide, were evaluated by using various equipment to determine the cause of a fire explosion accident. As a result of DSC analysis, the instantaneous power density of TBPM was 26,401 kW/ml, and the NFPA reactive index(Nr) was classified as 4. And the positive value of EP(explosive propagation) and SS(shock sensitivity) showed that the TBPM had a potential hazard of explosion. From the experimental results, the shock sensitivity and friction sensitivity was rated as class 4 and 5, respectively. In the pressure vessel test, TBPM was ranked USA-PVT No.4 and evaluated as a self-reactive substance. In the combustion rate test, TBPM had the combustion rate of 167 mm/sec and was evaluated as the flammable solid classification 2 in GHS.

• Journal of Bio-Environment Control
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• v.33 no.2
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• pp.88-98
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• 2024

This study provides basic data on the growth and production of seedlings produced in plant factories with artificial lighting by comparing seedling quality, growth and fruit characteristics, and production after transplanting cucumber seedlings according to environmental differences between plant factories with artificial lighting and conventional nurseries in greenhouse. The control group consisted of greenhouse seedlings (GH) grown in the conventional nursery before transplanting. Plant factory to greenhouse seedlings (PG) were grown for 9 days in a plant factory with artificial lighting and for 13 days in an conventional nursery. Plant factory seedlings (PF) were grown in a plant factory with artificial lighting for 22 days until planting. In terms of seedling quality, PFs had the highest relative growth rate and compactness and the best root zone development. After transplanting PFs tended to grow faster, the first harvest date was 2 days earlier than that of GHs, and the growing season ended 1 day earlier. The female flower flowering rate of the PFs was high, and the fruit set rate was of PF the lowest. The production per unit area was highest for PFs at 10.23kg Performance index on the absorption basis, the most sensitive chlorophyll fluorescence parameter, was highest at 4.14 for PFs at 4 weeks after transplantation. By comparing the maximum quantum yield of primary PS II photochemistry and dissipated energy flux per PS II reaction center electron at 4 weeks after transplantation, PFs tended to be the least stressed. PFs had the best seedling quality, growth, and production after planting, and fruit quality was consistent with that of greenhouse seedlings. Therefore, plant factory seedlings can be used in the field.