• Journal of Integrative Natural Science
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• v.14 no.2
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• pp.41-49
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• 2021

The causes of climate change are natural and artificial. Natural causes include changes in temperature and sunspot activities caused by changes in solar radiation due to large-scale volcanic activities, while artificial causes include increased greenhouse gas concentrations and land use changes. Studies have shown that excessive carbon use among artificial causes has accelerated global warming. Climate change is rapidly under way because of this. Due to climate change, the frequency and cycle of infectious disease viruses are greater and faster than before. Currently, the world is suffering greatly from coronavirus infection-19 (COVID-19). Korea is no exception. The first confirmed case occurred on January 20, 2020, and the number of infected people has steadily increased due to several waves since then, and many confirmed cases are occurring in 2021. In this study, we conduct a study on climate change before and after COVID-19 using weather data from Korea to determine whether climate change affects infectious disease viruses through logistic regression analysis. Based on this, we want to classify before and after COVID-19 through a logistic regression model to see how much classification rate we have. In addition, we compare monthly classification rates to see if there are seasonal classification differences.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.142-155
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• 1992

Numerical analysis is performed for the unsteady axisymmetric two dimensional phase change problem of freezing of water around a vertical tube. Heat conduction in the tube wall and solid phase, natural convection in liquid phase and volume expansion caused by density difference between solid and liquid phases are included in the numerical analysis. Existing correlation is used for estimating density-temperature relation of water, and the effect of volume expansion is reflected as fluid velocity at the interface and the free surface. As pure water has maximum density at 4.deg. C, it is found that there exists an initial temperature at which the flow direction reverses near the interface and by this effect the slope of interface becomes reversed depending on the initial temperature of water. By considering natural convection and solid-liquid density difference in the calculation, their effects on phase change process are studied and the effects of various parameters are also studied quantitatively.

• The korean journal of orthodontics
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• v.17 no.1
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• pp.55-62
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• 1987

Diagnosis and treatment plans of patients are depended on cephalogram in most case. However, conventional cephalogram may change diagnosis because it ignores a conception of natural head position. The purpose of this study was to investigate the difference of head positions between conventional X-ray taking and x-ray taking in natural head position, and correlation between above results and craniofacial morphology, 60 male students in dental college, Yon sei Univ. were selected, and every cephalogram is studied by comparison of the change of head position. The results are as follows. 1. When taking X-ray by using conventional method, external auditary meatus FH was more tilted than ear rod FM by $2.1^{\circ}{\pm}1.8$ in forward and downward direction. 2. As facial form becomes concave, natural head position and head position, appeared in X-ray taking by using conventional method, become more similiar. 3. Change in head position had showed high correlations with facial form (N-A-Pog angle), and there was high significance to concave group when compared with average group, but significance to convex group was not found. 4. Multiple regression equation concerning change of head position was solved. ${\Delta}FH=24.5\;+\;0.31$ NAPog + 0.43 Prominence of Chin + 0.13 Facial length -0.32 Anterior facial height.

• Journal of Korean Society of Rural Planning
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• v.19 no.4
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• pp.47-54
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• 2013

Climate change is the most direct threatening factors in sustaining agricultural productivity. It is necessary to reduce the damages from the natural hazards such as flood, drought, typhoons, and snowstorms caused by climate change. Through the vulnerability assessment to adapt the climate change, it is possible to analyze the priority, feasibility, effect of the reduction policy. For the vulnerability assessment, broad amount of weather data for each meterological station are required. Making the database management system for the meteorologic data could troubleshoot of the difficulties lie in handling and processing the weather data. In this study, we generated the meteorologic data retrieval system (MetSystem) for climate change vulnerability assessment. The user interface of MetSystem was implemented in the web-browser so as to access to a database server at any time and place, and it provides different query executions according to the criteria of meteorologic stations, temporal range, meteorologic items, statistics, and range of values, as well as the function of exporting to Excel format (*.xls). The developed system is expected that it will make it easier to try different analyses of vulnerability to natural hazards by the simple access to meteorologic database and the extensive search functions.

• Journal of Appropriate Technology
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• v.5 no.2
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• pp.118-125
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• 2019

Climate change is one part of 17 Sustainable Development Goals (SDGs). According to the Fifth Assessment Report by the Inter- governmental Panel on Climate Change(IPCC) published in 2014, global warming is caused by greenhouse gas (GHG) emissions. The most important GHG is carbon dioxide (CO₂), which is released by the burning of fossil fuels and, to a lesser extent, by land use practices, followed by nitrous oxide and methane. IPCC predicts that global temperatures will rise 3.7℃ and sea level will rise 0.63 m by 2099 in the case of no strong restraint. According to the report, we can expect a massive species extinctions, changes in storm and drought cycles, altered ocean circulation, and redistribution of vegetation by global warming. However, climate changes, especially global warming, are the largest potential threat to human health and the source of a number of diseases globally. If climate changes are continued uncontrolled, human health will be adversely affected by the accelerating climate change and the natural disaster induced by climate change. It means we will face more serious conditions of injury, disease, and death related to natural disasters such as flood, drought, heat waves, malnutrition, more allergy, air pollution and climate change related infections related to morbidity and mortality. This review emphasizes on the relationship between global climate changes and human health and provides some suggestions for improvement.

• Journal of Fashion Business
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• v.26 no.3
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• pp.87-97
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• 2022

This study investigated the dyeability and color change of the natural dyes of SeaCell, a biodegradable functional fiber that is permanently added to cellulose fibers with natural additives extracted from seaweeds. The natural dyes used in the study are five dyes. Gardenia and turmeric, which are yellow-based natural dyes, Sappan wood and Lac, which are red-based natural dyes, and Indigo, a blue-based natural dye, were selected. The dyeability and color change according to the change of the mordant conditions and the number of times of dyeing were investigated. In addition, the dyeing properties and colors of cotton and silk fibers were compared under the same dyeing conditions as SeaCell. The study results are as follows. It was found that SeaCell had lower dyeing properties than silk, a protein fiber, in gardenia, sappan wood, and lac dyes, but had higher dyeing properties than cotton with the same cellulose component as SeaCell fibers. In the case of turmeric, it showed higher dyeing properties than cotton except for the no mordant condition. In the case of Indigo dye, SeaCell shows the best dyeability, indicating that it is a very suitable fiber for Indigo dyeing. As sustainable functional fibers are continuously developed in the future, natural dyes that are environmentally friendly and human-friendly are actively introduced and commercialized, and it is expected that they can be used as reference materials.

• The Journal of Korean Academy of Prosthodontics
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• v.19 no.1
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• pp.47-54
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• 1981

Dental porcelains are widely used for restorative material because of its excellent esthetic property. But according to contact with natural teeth or metal in oral cavity, the porcelain may be worn and may effect on masticatory physiology and prosthetic function. The purpose of this experiment was to study on wear of porcelain surface which treated in different method. Using the abrasion device which was designed and constructed by myself, the different porcelain surface were abraded by gold alloy, nickel-chrome alloy and natural teeth in order to compare roughness. Results were as follows. 1. The group of porcelain abraded by gold alloy showed less surface roughness change (t=2.92, p<0.05), and the group of porcelain abraded by natural teeth had high surface roughness. change (t=6.84, p<0.05). 2. According to the method of surface treatment, the surface roughness were very significant (F=9.12, p<0.05). 3. After abrading, the porcelain surface roughness change was very significant (F=54.49, p<0.05). 4. There was no significant between surface treatment method and the kind of abrading materials. (F=1.01, p>0..05). 5. The group of natural glazing had the most smooth surface ($2.1{\pm}1.13{\mu}m$).

• ALGAE
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• v.35 no.4
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• pp.375-388
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• 2020

Ocean acidification and warming, identified as environmental concerns likely to be affected by climate change, are crucial determinants of algal growth. The ichthyotoxic raphidophytes Chattonella species are responsible for huge economic losses and environmental impact worldwide. In this study, we investigated the impact of CO2 on the thermal performance curves (TPCs) of Chattonella marina and Chattonella ovata grown under temperatures ranging from 13 to 34℃ under ambient pCO2 (350 μatm) and elevated pCO2 (950 μatm). TPCs were comparable between the species or even between pCO2 levels. With the exception of the critical thermal minimum (CTmin) for C. ovata, CTmin for C. marina and the thermal optimum (Topt) and critical thermal maximum (CTmax) for both species did not change with elevation of pCO2 levels. While CO2 enrichment increased the maximum photosynthetic rates (Pmax) up to 125% at the Totp of 30℃, specific growth rates were not significantly different under elevated pCO2 for the two species. Overall, C. ovata is likely to benefit from climate change, potentially widening its range of thermal tolerance limit in highly acidic waters and contributing to prolonged phenology of future phytoplankton assemblages in coastal waters.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.160-160
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• 2022

Floods are the most common natural disasters and are annually causing severe destructions worldwide. Human activities, along with expected increased extreme precipitation patterns as a result of climate change enhance the future potential of floods. There are proven evidence that infrastructure based responses to flood disaster is no longer achieving optimum mitigation and have created a false sense of security. Nature-based solutions(NBS) is a widely accepted sustainable and efficient approach for disaster risk reduction and involves the protection, restoration, or management of natural and semi-natural ecosystems to tackle the climate and natural crisis. Adoption of NBS in decision-making, especially in developing nations is limited due to a lack of sufficient scenario-based studies, research, and technical knowledge. This study explores the knowledge gap and challenges on NBS adoption with case study of developing nation, specially for flood management, by the study of multiple scenario analysis in the context of climate, land-use change, and policies. Identification and quantification of the strength of natural ecosystems for flood resilience and water management can help to prioritize NBS in policymaking leading to sustainable measures for integrated flood management.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.51-57
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• 2013

The process of liquefied natural gas is less then $-160^{\circ}C$ to natural gas by cooling at atmospheric pressure. When control strategy was made, one of the most significant is analysis of process. It is important to understand the control variable change according to manipulated variable change. In this study, we experiment natural gas liquefied process using C3MR(Propane Pre-cooled Mixed Refrigerant) process by BSU(Bench Scale Unit). We analyzed the change of refrigerant temperature and natural gas temperature according to the change of refrigerant flow rate so as to search an influence flow rate according to adjust each manipulated variables. One of the manipulated variable affected a number of control variables, but were able to confirm a control variable with a large response.