• Journal of Digital Convergence
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• v.14 no.4
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• pp.239-249
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• 2016

In this study, the personality type of youths was divided into 4 areas: Open, Blind, Hidden and Unknown, and the four different types were analysed according to the impact on smartphone addiction. The survey was conducted on 406 middle school students in Jeonbuk province to assess the relationship between smartphone addiction of youth and the personality type. The results of this study are as follows: First, the difference of smartphone addiction in youth between genders is not large, but males were largely affected by tolerance, while females by difficulty of daily living. Second, the differences of smartphone addiction between grades found that difficulty of daily living and tolerance had a statistically significant impact. Third, the result of co-relationship between the Johari window type of mind and smartphone addiction showed that blind type and unknown type had a statistically significant positive relationship but open type had a negative impact. Finally, analysis of variables about whether a type of mind affected smartphone addiction showed that there was a relationship. The most serious type of addiction to smartphones showed in hidden type and unknown type. Therefore in developing programs to treat smartphone addiction it should seek specific measures to help these groups.

• 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.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.161-171
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• 2023

It is largely agreed that elderly drivers (over 64 years) are more likely to cause fatal crashes than other age groups. According to national road crash statistics 2021, the number of road fatalities per 10,000 drivers over 64 years old was 1.77, while that of drivers in their 30s was 0.55. This indicates a 2.67 times higher probability of causing crashes among the former than the latter. The current study estimates how rear-end crashes may be reduced by installing Automatic Emergency Braking Systems (AEBS), particularly for elderly drivers. We analyzed data from Samsung Fire & Marine Insurance. The results show that the Odds Ratio of rear-end crash occurrence between vehicles with AEBS and without AEBS is 0.75, implying there were lesser rear-end crashes in the vehicles installed with AEBS. The Odds Ratio of male drivers was determined to be 0.78, which was lesser than the 0.81 Odds Ratio obtained for female drivers. Elderly drivers who had installed AEBS in their vehicles showed an Odds Ratio of 0.76, implying crash reduction. In particular, the Odds Ratio of male elderly drivers was found to be the lowest at 0.49. We believe incentivizing by giving discounted insurance premiums to the elderly who drive vehicles installed with AEBS will help reduce rear-end crashes.

• Food Science and Preservation
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• v.13 no.6
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• pp.789-795
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• 2006

This study was designed to investigate quality characteristics of Korean cabbage kimchi added with germinated brown rice extracts (GBRC; (A) and CBREP; (B)) and Korean cabbage kimchi on the market mom the result pH and total acidity were shown to be similar in all samples. In the case of Korean cabbage kimchi added with (A) and (B), content of total sugar and reducing sugar were higher than those of Korean cabbage kimchi on the market. Color values (L, b) were shown to be similar in all samples in which a value was lower than that of Korean cabbage kimchi on the market. The amounts of total amino acid and free amino acid of Korean cabbage kimchi added (A) and (B) were higher than those of Korean cabbage kimchi on the market. But the amount of $\gammma$-aminobutyric acid (GABA) in main functional components of germinated brown rice was shown to be low. Total phenol content and other antioxidant and anticoagulant activities of Korean cabbage kimchi fortified with (A) and (B) were higher than those of Korean cabbage kimchi on the market. In conclusion, Korean cabbage kimchi added with (A) and (B) were shown to be similar in fermentation tendency compared to Korean cabbage kimchi on the market and, the functional properties could be enhanced by the addition of (A) and (B).

• Journal of the Korean Institute of Gas
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• v.14 no.6
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• pp.15-20
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• 2010

Compressed Natural Gas (CNG) buses have been supplied since the year 2000 in order to resolve severe atmospheric pollution in metropolitan area and contributed on the improvement of urban atmospheric environment. However, it is indispensible to take an adequate measure to guarantee the safety of CNG vehicles because of the possibility of huge fire accident. A receptacle, connecting device between high pressure fuel supply tank and fuel line, plays an important role in CNG supply system. In recent, leakage of CNG from receptacles has been reported. So, the concern about the security and reliability of receptacles has been arisen. Therefore, a lot of efforts to prevent leakage are invested among researchers and the durability of this component should be guaranteed despite repeated operation. This research has performed durability tests of a CNG receptacle regarding the repeated usage, extreme chattering, and continuous full flow test. Although a receptacle used for CNG vehicle satisfies validation requirements in the test results, it has been found that failure in the function of leakage prevention in a receptacle could take place in the case of prolonged exposure to high supply pressure in common quick charging environment on site.

• Spatial Information Research
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• v.20 no.2
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• pp.155-164
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• 2012

Indoor fire simulators have been used to analyse building safety in the events of emergency evacuation. These applications are primarily focused on simulating evacuation behaviors for the purpose of checking building structural problems in normal time rather than in real time situations. Therefore, they have limitations in handling real-time evacuation events with the following reasons. First, the existing models mostly experiment the artificial situations using randomly generated evacuees while real world requires actual data. Second, they take too long time in operation to generate real time data. Third, they do not produce optimal results to be used in rescueing or evacuation guidance. In order to solve these limitations, we suggest a method to build an evacuation simulation system that can be used in real-world emergency situations. The system performs numerous simulations in advance according to varying distributions of occupants. Then the resulting data are stored in DBMS. The actual person data captured in infrared sensor network are compared with the simulation data in DBMS and the querried data most closely is provided to the user. The developed system is tested using a campus building and the suggested processes are illustrated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.707-716
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• 2009

The levels of psychosocial stresses and fatigue of firemen were analyzed to reveal the various factors related to them. The self-administered questionnaires were performed to 262 firemen ill Cheonsju City. In terms of various levels of psychosocial stresses, 12.2% were under potential stresses, 87.8% were under high-level of stress, but healthy group was not found. The levels of fatigue symptoms divided by the median of total scores was 51.1% of low levels, and 48.9% of high levels. Multiple stepwise analysis revealed that the factors or influence on psychosocial stresses with explanatory powers of 11.5% included subjective health status, job satisfaction, job demand and alcohol drinking habits. The factors of influence on fatigue symptoms with explanatory powers of 9.0% included subjective health and regular exercises. The study results indicate that the level of stress or fatigue is so complicatedly influenced by variable factors. Thus the effective strategy for stress and fatigue reduction among firemen should include additional programs focusing on health promotion.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.425-432
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• 2015

Pollution in the fresh water system in urban area has the adverse effect on the amphibians population. Restoration activity of amphibian in the urban stream has been growing in Korea as well as western country. For successful restoration water quality of urban stream should be sufficient for survival and normal development of amphibian. To monitor the biological safety of surface water in the Tancheon basin, the capital area of Korea, a 6-day exposure Bombina orientalis embryo developmental toxicity assay was examined. The toxicity of surface water of Tancheon mainstream were lower than those of tributaries of Tancheon. The survival rate of embryos negatively correlated with total dissolved solid, turbidity and electrical conductivity whereas the developmental abnormality and growth retardation of embryos was positively correlated with total dissolved solid, turbidity and electrical conductivity. An amphibian developmental toxicity assay would be helpful for the selection of point for construction of habitat and reintroduction of amphibian in interrupted urban stream.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1161-1175
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• 2018

An unexpected event could be easily followed by a large secondary accident due to the limitation in sight of drivers in road tunnels. Therefore, a series of automated incident detection systems have been under operation, which, however, appear in very low detection rates due to very low image qualities on CCTVs in tunnels. In order to overcome that limit, deep learning based tunnel incident detection system was developed, which already showed high detection rates in November of 2017. However, since the object detection process could deal with only still images, moving direction and speed of moving vehicles could not be identified. Furthermore it was hard to detect stopping and reverse the status of moving vehicles. Therefore, apart from the object detection, an object tracking method has been introduced and combined with the detection algorithm to track the moving vehicles. Also, stopping-reverse discrimination algorithm was proposed, thereby implementing into the combined incident detection processes. Each performance on detection of stopping, reverse driving and fire incident state were evaluated with showing 100% detection rate. But the detection for 'person' object appears relatively low success rate to 78.5%. Nevertheless, it is believed that the enlarged richness of image big-data could dramatically enhance the detection capacity of the automatic incident detection system.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.521-531
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• 2021

Vacuum Pressure Impregnation (VPI) is a process that enhances physical properties by coating some types of epoxy resins on windings of stator used in large rotators such as generators and motors. During vacuum and pressurization of the VPI process, resin gas is generated by vaporization of epoxy resin. When the tank is opened for curing after finishing impregnation, resin gas is leaked out of the tank. If the leaked resin gas spreads throughout the workplace, there are safety and environmental problems such as fire, explosion and respiratory problems. So, exhaust system for resin gas is required during the process. In this study, a case study of exhaust efficiency by location of vent was conducted using Computational Fluid Dynamics (CFD) in order to design a system for exhausting resin gas generated by the VPI process. The optimal exhaust system of this study allowed more than 90% of resin gas to be exhausted within 1,800 seconds and reduced the fraction of resin gas below the Low Explosive Limit (LEL).