• Journal of The Geomorphological Association of Korea
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• v.23 no.1
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• pp.17-33
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• 2016

Samples from newly exposed outcrop of sedimentary layers forming Jeongdongjin coastal terrace in Gangreung area are collected and analyzed to find the sedimentary environment. The site are located at the gentle hillslope of the terrace surface area. The height of the outcrop is about 8m and the altitude of it's highest part is 68~73m MSL. The lowest part of this out crop is the partly consolidated sand layer with gravel veneer within it. It is found that this part is not in-situ weathered sand stone through the OSL method. This sand layer is overlain by the gravel layer with sand matrix. The shapes of the gravels from this part are mainly 'platy', 'elongated', and 'bladed' by the index of Sneed and Folk(1958). In addition, mean roundness is not so high. It is sceptical to regard this part as marine sediments which are continuously exposed to erosional processes. The boundary between the lowest sand layer and gravel layer showing the abrupt change in forming material without any mixture or transitional zone, so gravels are seemed to deposited after some degree of consolidation of the lowest sand layer. In addition, the hight of the boundary between layers are changed by the place, so the surface of the partly consolidated sand layer is not flat and has irregularity on topography when it buried by gravels. Main part of this out crop is the poorly sorted coarse gravel(22.4mm) with sand matrix($1.36{\phi}$) layer with at least 2m thick covering the relatively fine gravels discussed above. Over 20% of particles have 'very platy', 'very elongated' and 'very bladed' shape and only less than 5% of particles have 'compact' shape, So this particles are also very hard to be regard as marine gravels which are abraded by marine processes. It can be concluded that this gravel layer formed by fluvial processes rather than coastal processes base on the form of the clast and sedimentary structure. The gravel layer is covered by fine($3{\sim}4{\phi}$) material layers of psudo-gleization which showing inter-bedding of red and white layers. Chemical composition of matrix and other fine materials should be analyzed in further studies. It is attempted to fine the burial ages of the sediment using OSL method, but failed by the saturation. So it can be assumed that these sediments have be buried over 120ka.

• Journal of Rhinology
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• v.25 no.2
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• pp.69-74
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• 2018

Background and Objectives: Sleep disturbances and excessive daytime sleepiness (EDS) are the major symptoms of obstructive sleep apnea (OSA). This study aimed to investigate clinical implications of insomnia and EDS in patients with OSA using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Materials and Method: We evaluated 131 subjects with suspected OSA who were undergoing polysomnography (PSG) and performing the PSQI and ESS surveys. OSA was diagnosed when the apnea-hypopnea index was five or more. EDS was defined when ESS score was 11 points or higher. Detailed history and questionnaire were used to categorize insomnia. We compared clinical variables and PSG results in subgroups with or without insomnia and EDS. Results: There were no significant differences of PSQI and ESS score between controls and OSA. OSA with insomnia had significantly increased total score (p<0.001) and decreased total sleep time (p=0.001) and sleep efficiency (p=0.001) on the PSQI compared to those without insomnia. OSA with EDS showed significantly increased PSQI score (p=0.022) and decreased total sleep time (p=0.018) on PSG compared to those without EDS. Neither PSQI nor ESS score had a correlation with respiratory variables such as AHI and oxygen saturation. Total sleep time had a significant effect on both insomnia and EDS in patients with OSA. Conclusion: Decreased total sleep time had important effects on subjective symptoms of OSA and comorbid insomnia. Therefore, restoration of decreased sleep time is important in the management of OSA.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.3
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• pp.141-148
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• 2021

Agrivoltaic systems, also called solar sharing, stated from an idea that utilizes sunlight above the light saturation point of crops for power generation using solar panels. It is expected that agrivoltaic systems can realize climate smart agriculture by reducing evapotranspiration and methane emission due to the reduction of incident solar radiation and the consequent surface cooling effect and bring additional income to farms through solar power generation. In this study, to evaluate that agrivoltaic systems are suitable for realization of climate smart agriculture, we conducted agro-environmental observations (i.e., downward/upward shortwave/longwave radiations, air temperature, relative humidity, water temperature, soil temperature, and wind speed) in a rice paddy under an agrivoltaic system and compared with the environment outside the system using automated meteorological observing systems (AMOS). During the observation period, the spatially averaged incoming solar radiation under the agrivoltaic system was about 70% of that in the open paddy field, and clear differences in the soil and water temperatures between the paddy field under the agrivoltaic system and the open paddy field were confirmed, although the air temperatures were similar. It is required in the near future to confirm whether such environmental differences lead to a reduction in water consumption and greenhouse gas emissions by flux measurements.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.3
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• pp.313-329
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• 2021

This study analyzed the characteristics of the management crisis, the level of resilience, and the alternatives based on the companies' self-evaluation of the game industry in Daegu. The Daegu game industry, which started spontaneously in the late 1990s, grew rapidly until the late 2000s with the support of the government and supporting organizations. However, from the mid-2010s, it has entered a period of recession due to the number of companies that failed to respond to the saturation of the mobile game market and fierce competition at home and abroad. In response, some game companies turned the crisis into an opportunity to strengthen their competitiveness by pursuing challenging strategies for product differentiation and pioneering new markets. On the other hand, companies that were passive in responding to the crisis have not get out of the management crisis. In addition, in terms of the resilience level of game companies in Daegu, the level of immediate response to shock(rapidity) and replacement of the damaged part(redundancy) was low, but the level of mobilizing sufficient resources internally(resourcefulness) was high. However, as the Daegu game industry is facing more complex multi-spatial-scale environmental changes than in the past, its resilience should be strengthened through strategies that can compensate for weaknesses in terms of the game industry ecosystem beyond individual company-level efforts.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.153-161
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• 2021

The exterior color of the building reflects its style. With the advancement of the 'Village Art' project in South Korea, many villages have gradually developed into tourist attractions. Therefore, it is also important to distinguish between residents' lifestyles and tourist needs through architectural color design. This article first investigates the literature and analyzes the use function of the building and the role of the exterior color in the villages. Secondly, the four types of buildings in Huinnyeoul Culture Village: residential, commercial, leisure, and public toilets are investigated as the research objects. Analyze through the KSCA color measurement analysis system and questionnaire survey, and propose a color plan for the exterior of the building. Research results: First, the main color area of the outer wall of the residential building should be the largest, with a tendency of high brightness and low saturation. Second, small buildings with high chroma in the recreation area can be used as visual guidance.Third, the buildings in the commercial area are mainly of high brightness, high chroma, and multi-hue. Fourth, the main color of the bathroom is the main color of the residential area and the leisure area, which can provide a sense of visual stability.

• Journal of the Korean Geosynthetics Society
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• v.20 no.2
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• pp.1-11
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• 2021

In this study, a study related to laboratory and pilot test were performed to use an environmental soil stabilizer developed to induce a hardening reaction similar to that of Ordinary Portland Cement (OPC) by using industrial by-products of blast furnace slag and the combustion ash of a circulating fluidized bed boiler as the main material. For this, specimens were prepared using liquid A of sodium silicate and silica sol, and liquid B of an environmental soil stabilizer (or OPC), and laboratory tests were performed to analyze the strength and environmental characteristics. And pilot test was performed on the aging reservoir, field permeability test and electrical resistivity survey were performed in the field to analyze the applicability. As a result of the laboratory test, the homo-gel compressive strength of the chemical injection material using the environmental soil stabilizer as liquid B was about 2.88 to 3.23 times greater than that of OPC. In addition, the elution amount of most heavy metals was lower than that of OPC, and the survival rate in the fish, acute toxicity test was 100%. Therefore, when judged based on the results of the laboratory test, it was analyzed to be superior to OPC in terms of strength and environment. In the results of the pilot test in the aging reservoir, when the environmental soil stabilizer was reinforced with liquid B of the chemical injection material, the coefficient of permeability in the aging reservoir decreased to 1/50 level. In addition, as a result of the electrical resistivity survey, it was analyzed that the electrical resistivity inside the aging reservoir increased as time passed, the saturation zone disappeared, and the overall reinforcement.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.733-737
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• 2011

We investigated the effect of artificial warming on chlorophyll contents and net photosynthetic rates of 2-year-old Quercus variabilis seedlings in a nursery open-field experiment site. 64 seedlings were each planted in $1m{\times}1m$ plots (n = 4) and warmed with infrared lamps. The air temperature in warmed plots was $3^{\circ}C$ higher than that of control plots. Chlorophyll contents and net photosynthetic rates were measured in May, July, August, September and October, 2011. In May, September and October chlorophyll contents and net photosynthetic rates were significantly higher in warmed plots than in control plots. However, there were no significant differences in chlorophyll contents and net photosynthetic rates between warmed plots and control plots in July and August. It seemed that early developed leaves of warmed plots in May with higher chlorophyll contents could lead to higher net photosynthetic rates whereas there was no difference in net photosynthetic rates due to saturation of chlorophyll contents in July and August. Increased biosynthesis of chlorophyll due to warming might increase net photosynthetic rates in September and October.

• Journal of The Korean Society of Clinical Toxicology
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• v.19 no.1
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• pp.8-16
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• 2021

Purpose: This study was conducted to analyze the social factors influencing the 'authenticity of suicidal ideation' based post-suicidal care programs in emergency departments (EDs). Methods: This retrospective study was an analysis using the data of patients who had attempted suicide and visited the ED in tertiary urban hospitals from January 1, 2016, to December 31, 2018. The variables examined included gender, age, history of previous psychiatric disease, suicide method, and the number of previous attempts. Univariate and multivariate logistic regression analyses were conducted to identify factors influencing the registration rate for the community-based post-suicide care program. Results: Overall,1,460 suicides were analyzed, 177 (1.16%) showed a high authenticity of suicide. The social factors influencing the authenticity of suicide intent were the unmarried status of men and women, joblessness, history of mental illnesses, more than two previous suicide attempts, the influence of alcohol, and an attempt to commit suicide after midnight more specifically between 24:00 to 6:00 hours in the morning (p<.05). The factors influencing the severity of the condition of high authenticity suicide patients were low Glasgow coma scores (12 points or less), lactate levels, and oxygen saturation observed in the patients who were admitted to the intensive care unit for treatment and died (p<.05). Conclusion: The need for evidence-based preventive measures and early assessment tools at the emergency medicine level is emphasized to reduce the rate of suicide attempts. If the results of this study are used in the management of suicide prevention, the evaluation of the authenticity of suicide intent will be more likely to be made at the emergency medicine level, allowing the severity to be assessed earlier.

• Journal of the Korean Geosynthetics Society
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• v.20 no.1
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• pp.45-55
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• 2021

In this study, the behavioral characteristics of the fill dam were analyzed during water level fluctuations through a numerical analysis model, and the reservoir safety management plan was prepared. The variation in plastic deviatoric strain, horizontal displacement, stress path, pore water pressure, etc., due to elevation of water level in the upper and lower sides of shell and core were analyzed using numerical analysis software, viz. GTS NX and LIQCA. The analysis results manifest that as the water level in the dam body increases rapidly, the pore water pressure and displacement also increase quickly. It was found that the elevation of the water level causes an increase in pore water pressure in the dam body as well as an increase in the saturation of the dam body and decreased effective stress. It is considered that this type of dam behavior can be the cause of the reduction of strength and stiffness of the dam. Also, it is assumed that the accumulated plastic deviatoric strain due to the deformation of the dam body caused by water infiltration causes an increase in displacement. Based on these experimental results and the results of analyses of the existing reservoir safety diagnosis techniques, an improvement plan for dam safety diagnosis and evaluation criteria was proposed, and these results can be used as primary data while revising dam safety diagnosis guidelines.

• Journal of the Korean GEO-environmental Society
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• v.22 no.3
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• pp.5-13
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• 2021

Due to population growth and industrial development, the amount of industrial waste is increasing every year. In particular, in a thermal power plant using finely divided coal, a large amount of coal ash is generated after combustion of the coal. Among them, fly ash is recycled as a raw material for cement production and concrete admixture, but about 20% is not utilized and is landfilled. Due to the continuous reclamation of such a large amount of coal ash, it is required to find a correct treatment and recycling plan for the coal ash due to problems of saturation of the landfill site and environmental damage such as soil and water pollution. In recent years, the use of a fluid embankment material that can exhibit an appropriate strength without requiring a compaction operation is increasing. The fluid embankment material is a stable treated soil formed by mixing solidifying materials such as water and cement with soil, which is the main material, and has high fluidity before hardening, so compaction work is not required. In addition, after hardening, it is used for backfilling or filling in places where compaction is difficult because higher strength and earth pressure reduction effect can be obtained compared to general soil. In this study, the possibility of use of fluidized soil using high water content cohesive soil and coal ash is considered. And it is intended to examine the flow characteristics, strength, and bearing capacity characteristics of the material, and to investigate the effect of reducing the earth pressure when applied to an underground burial.