• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.507-512
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• 2019

To study how illuminance affects cognitive ability of the elderly, the elderly's EEG, concentration, HRV and vibra image were measured in a test room with temperature $25[^{\circ}C]$, relative humidity 50[RH%] and air flow speed 0.02[m/sec] by varying illuminance to 100[lux], 300[lux], 600[lux], 1000[lux] and 1500[lux]. Ten active elderly males were selected as subjects. Experiment condition was fixed as 1met of activity amount where the subject is seated and relaxed with cloth amount of 0.7clo. As a result, 1000[lux] was found out to be the most pleasant illuminance for the elderly, because $M{\beta}$ increased by 66.35%, and $S{\alpha}$ increased by 31.57% when the elderly was under 1000[lux] of illuminance. Also, concentration under 1000[lux] increased by 8.83% compared to 100[lux], and the pattern of concentration maintained uniformly. SDNN increased by 74.94% under 1000[lux] compared to 100[lux]. Nervousness decreased by 97.23% under 1000[lux] compared to 100[lux]. Moreover, HRT notably increased and aggression remarkably decreased under illuminance of 1000[lux]. Thus, based on the fact that comfort, concentration and heart stability of the elderly reach the highest under 1000[lux], it is determined that the illuminance has to be considered foremost in designing the elderly's welfare facilities to raise their safety and level of independence.

• Journal of the Society of Disaster Information
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• v.14 no.4
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• pp.480-491
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• 2018

Purpose : This study aims to suggest social support composed of organizational support and managerial support would be systematically managed to enhance Disaster Operations Management at Seoul Emergency Operations Center. Method : Emotional labor was used as an independent variable, and organizational commitment was used as a dependent variable to analyze the mediating effects of social support. Results : First, in the aspect of organizational support, the objective evaluation of disaster situation management, disaster situation management emotional labor reduction education and training program development, monitoring of disaster situation management, quality improvement and work imbalance mitigation of firefighters, and emergency coordination managers are needed for systematic work management for emotional labor settlement. Secondly, it is necessary to select competent firefighters in the level of managerial support, to prepare healing measures for structured phased emotional labor for firefighters, and to have counseling competency for managers for emotional labor firefighting officers. Conclusion : In order to improve disaster management ability, education and training programs should be developed to improve organizational commitment based on social support.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.52-65
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• 2021

In this study, authors analyzed the vapor cloud explosion induced by propane leak at the PEMIX Terminal, which is the propane storage facility outside of Mexico City. TNT equivalence mass for the leaked 4750 kg propane was estimated to be 9398 kg. Blast parameters such as peak overpressure, positive phase duration, and impact at 40-400 (m) away from the center of the explosion were calculated by applying TNT Equivalency Method and Multi-Energy Method. The probability of damage due to lung damage, eardrum rupture, head impact, and whole-body displacement impact by applying the probit function obtained using blast parameters was evaluated. The peak overpressure obtained using Multi-Energy Method was found to be greater than the peak overpressure obtained by applying the TNT Equivalency Method at all distances considered, but it was evaluated that there was no significant difference from the points above 200 m. The peak overpressure obtained by Multi-Energy Method was computed to assess the extent of damage to the structure, and it was shown that structures within 100 m of the explosion center would collapse completely, and that the glasses of the structures 400 m away would be almost broken. The probability of death due to lung damage was shown to vary depending on a human body's position located in the propagating direction of shock wave, and if there is a reflecting surface in the immediate surroundings of a human body, the probability of death was estimated to be the greatest. The impact of shock wave on lung damage, eardrum rupture, head impact, and whole-body displacement impact was evaluated and found to affect whole-body impact < lung damage < eardrum rupture

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.1
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• pp.46-54
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• 2021

This study compared and analyzed the effects of forest tending works on the vertical distribution of wildfire fuel loads on Pinus densiflora stands in Gyeongbuk province. The study sites were located in Youngju and Bonghwa in Pinus densiflora stands. A total of 10 sample trees were collected for the development of the crown fuel vertical distribution model. The 6th NFI (National Forest Inventory) selected a sample point that only extracted from managed and unmanaged stands of Pinus densiflora in the Gyeongbuk province. The fitness index (F.I.) of the two models developed was 0.984 to 0.989, with the estimated parameter showing statistical significance (P<0.05). A s a results, the vertical distribution of wildfire fuel loads range of unmanaged stands was from 1m to 11m with the largest distribution at point 5m at the tree height. On the other hand, the vertical distribution of wildfire fuel loads range of the managed stands was from 1m to 15m with the largest distribution at the point of 8m at the tree height. The canopy bulk density was 0.16kg/㎥ for the managed stands and 0.25kg/㎥ for the unmanaged stands, unmanaged stands were about 1.6 times more than managed stands. This result is expected to be available for simulation through the implementation of the 3D model as crown fuel was analyzed in three dimensions.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.69-83
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• 2023

Forest fires increase the risk of subsequent soil erosion and mass movement in burned areas, even under rainfall conditions below landslide alert thresholds, by destroying plants and vegetation and causing changes to soil properties. These effects of forest fires can alter runoff in burned areas by altering soil composition, component minerals, soil water repellency, soil mass stability, and soil fabric. Heat from forest fires not only burns shallow organic matter and plants but also spreads below the surface, affecting soil constituents including minerals. This study analyzed X-ray diffraction and physical properties of topsoil and subsoil obtained from both burned and non-burned areas to identify the composition and distribution of clay minerals in the soil. Small amounts of mullite, analcite, and hematite were identified in burned soils. Vermiculite and mixed-layer illite/vermiculite (I/V) were found in topsoil samples from burned areas but not in those from non-burned areas. These findings show changes in soil mineral composition caused by forest fires. Expansive clay minerals increase the volume of soil during rainfall, degrading the structural stability of slopes. Clay minerals generated in soil in burned areas are therefore likely to affect the long-term stability of slopes in mountainous areas.

• Anxiety and mood
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• v.18 no.2
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• pp.39-47
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• 2022

Objective : This study investigated brain functional connectivity in male firefighters who showed subclinical post-traumatic stress disorder (PTSD) symptoms. Methods : We compared the data of 17 firefighters who were not diagnosed with PTSD and 18 healthy controls who had no trauma exposure. The following instruments were applied to assess psychiatric symptoms: Korean version of the Post-traumatic stress disorder Checklist for DSM-5 (PCL-5-K), Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory (BAI). For all subjects, functional magnetic resonance imaging was performed, and functional connectivity was compared between the two groups (family-wise error-corrected p<0.05). Additionally, correlations between psychiatric symptoms and functional connectivity were explored. Results : The following connectivity was higher than that of healthy controls: 1) the central opercular cortex-superior temporal gyrus, 2) planum polare-parahippocampal gyrus, 3) angular gyrus-amygdala, and 4) temporal fusiform cortex-parahippocampal gyrus. The functional connectivity of 1) the lateral occipital cortex-inferior temporal gyrus, 2) superior parietal lobule-caudate, and 3) middle temporal gyrus-thalamus were lower in firefighters. In firefighters, the connectivity of the planum polare-parahippocampal gyrus showed a negative correlation with the severity of arousal symptoms (rho=-0.586, p=0.013). The connectivity of the middle temporal gyrus-thalamus showed a positive correlation with the severity of intrusion (rho=0.552, p=0.022) and arousal symptoms (rho=0.619, p=0.008). The connectivity of the temporal fusiform cortex-parahippocampal gyrus was negatively correlated with intrusion (rho=-0.491, p=0.045) and arousal (rho=-0.579, p=0.015). Conclusion : Our results indicate that the brain functional connectivity is associated with occupational trauma exposure in firefighters without PTSD. Therefore, this study provides evidence that close monitoring and early intervention are important for firefighters with traumatic experience even at a subthreshold level.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.5
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• pp.251-264
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• 2022

Previous researches related to emotional labor have been cross-sectional studies focusing on static differences in emotional exhaustion. Previous studies on these relationships have not highlighted the dynamic properties of these relationships. This purpose of this study is to investigate the effect of emotional labor strategy on perceived emotional exhaustion and depression. This study was conducted by paying attention to the fact that service industry workers who have to respond kindly to customers often have to show emotions which is necessary for their business to the outside world rather than showing their true emotions. The results of this study are summarized as follows. First, it was confirmed that surface acting had a positive influence on emotional exhaustion, but deep acting had a negative influence to emotional exhaustion. Second, it was found that surface acting had a positive influence on depression, but deep acting had a negative influence on depression. Third, it was confirmed that the effect of deep acting on emotional exhaustion decreased when emotional labor was performed through deep acting on Mondays, Tuesdays, and Wednesdays, while emotional exhaustion was not significant on Thursdays and Fridays. Fourth, it was confirmed that the difference in the effect of emotional labor strategy on depression was greater in the case of performing emotional labor through surface acting than in the case of performing emotional labor through deep acting.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.407-417
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• 2024

The objective of this study is to predict and reduce potential damage caused by chlorine gas leaks, a hazardous material, when vehicles transporting it overturn due to accidents or other incidents. The goal is to forecast the anticipated damages caused by chlorine toxicity levels (ppm) and to design effective response strategies for mitigating them. To predict potential damages, we conducted quantitative assessments using the ALOHA program to calculate the toxic effects (ppm) and damage distances resulting from chlorine leaks, taking into account potential negligence of drivers during transportation. The extent of damage from toxic gas leaks is influenced by various factors, including the amount of the leaked hazardous material and the meteorological conditions at the time of the leak. Therefore, a comprehensive analysis of damage distances was conducted by examining various scenarios that involved variations in the amount of leakage and weather conditions. Under intermediate conditions (leakage quantity: 5 tons, wind speed: 3 m/s, atmospheric stability: D), the estimated distance for exceeding the AEGL-2 level of 2 ppm was calculated to be 9 km. This concentration poses a high risk of respiratory disturbance and potential human casualties, comparable to the toxicity of hydrogen chloride. In particular, leaks in urban areas can lead to significant loss of life. In the event of a leakage incident, we proposed a plan to minimize damage by implementing appropriate response strategies based on the location and amount of the leak when an accident occurs.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.5
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• pp.13-25
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• 2024

With the increasing wildfire damage driven by climate change, it is crucial to assess the effectiveness of restoration efforts on a large scale. The majority of forests in Korea are situated in rugged mountainous regions, making it challenging to monitor large-scale wildfires. Consequently, establishing methodologies that use satellite imagery to evaluate restoration effectiveness is essential. This study aims to assess the recovery trends of ecosystems in wildfire-affected areas using NDVI mean-variance plots, which monitor changes in NDVI mean and variance over time through satellite imagery and visually represent the restoration process. The analysis of NDVI mean-variance plots for different restoration methods revealed that landscape restoration had the slowest recovery. This slower recovery is likely due to reduced growth from the complete removal of damaged trees. In contrast to High Severity (HS) areas, Moderate High Severity (MHS) areas showed that commercial afforestation, revegetation, ecological forest treatment led to a more stable recovery state post-disturbance, suggesting that areas with lower wildfire severity may recover more quickly. Furthermore, the recovery trends between artificial and natural restoration showed no significant difference, indicating that natural restoration can have similar restoration effects to artificial restoration in appropriate areas. Therefore, the study emphasizes the need to expand natural restoration areas, considering ecological and economic benefits such as increased biodiversity and genetic resource conservation. This research provides critical baseline data for the formulation and implementation of restoration policies in large-scale wildfire-affected regions and is expected to contribute significantly to the development of effective management strategies and monitoring techniques.

• Journal of Intelligence and Information Systems
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• v.22 no.1
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• pp.119-138
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• 2016

Since the Industrial Revolution, which made the mass production and mass distribution of standardized goods possible, machine-made (manufactured) products have accounted for the majority of the market. However, in recent years, the phenomenon of purchasing even more expensive handmade products has become a noticeable trend as consumers have started to acknowledge the value of handmade products, such as the craftsman's commitment, belief in their quality and scarcity, and the sense of self-esteem from having them,. Consumer interest in these handmade products has shown explosive growth and has been coupled with the recent development of three-dimensional (3D) printing technologies. Etsy.com is the world's largest online handmade platform. It is no different from any other online platform; it provides an online market where buyers and sellers virtually meet to share information and transact business. However, Etsy.com is different in that shops within this platform only deal with handmade products in a variety of categories, ranging from jewelry to toys. Since its establishment in 2005, despite being limited to handmade products, Etsy.com has enjoyed rapid growth in membership, transaction volume, and revenue. Most recently in April 2015, it raised funds through an initial public offering (IPO) of more than 1.8 billion USD, which demonstrates the huge potential of online handmade platforms. After the success of Etsy.com, various types of online handmade platforms such as Handmade at Amazon, ArtFire, DaWanda, and Craft is ART have emerged and are now competing with each other, at the same time, which has increased the size of the market. According to Deloitte's 2015 holiday survey on which types of gifts the respondents plan to buy during the holiday season, about 16% of U.S. consumers chose "homemade or craft items (e.g., Etsy purchase)," which was the same rate as those for the computer game and shoes categories. This indicates that consumer interests in online handmade platforms will continue to rise in the future. However, this high interest in the market for handmade products and their platforms has not yet led to academic research. Most extant studies have only focused on machine-made products and intelligent services for them. This indicates a lack of studies on handmade products and their intelligent services on virtual platforms. Therefore, this study used signaling theory and prior research on the effects of sellers' characteristics on their performance (e.g., total sales and price premiums) in the buyer-seller relationship to identify the key influencing e-Image factors (e.g., reputation, size, information sharing, and length of relationship). Then, their impacts on the performance of shops within the online handmade platform were empirically examined; the dataset was collected from Etsy.com through the application of web harvesting technology. The results from the structural equation modeling revealed that the reputation, size, and information sharing have significant effects on the total sales, while the reputation and length of relationship influence price premiums. This study extended the online platform research into online handmade platform research by identifying key influencing e-Image factors on within-platform shop's total sales and price premiums based on signaling theory and then performed a statistical investigation. These findings are expected to be a stepping stone for future studies on intelligent online handmade services as well as handmade products themselves. Furthermore, the findings of the study provide online handmade platform operators with practical guidelines on how to implement intelligent online handmade services. They should also help shop managers build their marketing strategies in a more specific and effective manner by suggesting key influencing e-Image factors. The results of this study should contribute to the vitalization of intelligent online handmade services by providing clues on how to maximize within-platform shops' total sales and price premiums.