• KIPS Transactions on Software and Data Engineering
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• v.8 no.6
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• pp.243-250
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• 2019

Because of a moving UAV has a lot of potential/kinetic energy, if the UAV falls to the ground, it may have a lot of impact. Because this can lead to human casualities, in this paper, the population density area on the UAV flight path is defined as a dangerous area. The conventional UAV path flight was a passive form in which a UAV moved in accordance with a path preset by a user before the flight. Some UAVs include safety features such as a obstacle avoidance system during flight. Still, it is difficult to respond to changes in the real-time flight environment. Using public Big Data for UAV path flight can improve response to real-time flight environment changes by enabling detection of dangerous areas and avoidance of the areas. Therefore, in this paper, we propose a method to detect and avoid dangerous areas for UAVs by utilizing the Big Data collected in real-time. If the routh is designated according to the destination by the proposed method, the dangerous area is determined in real-time and the flight is made to the optimal bypass path. In further research, we will study ways to increase the quality satisfaction of the images acquired by flying under the avoidance flight plan.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.1
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• pp.195-201
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• 2019

Long caisson breakwaters can improve the structural safety of a caisson due to the wave dispersion effect which reduces the average wave force acting on one caisson. However, in order to make long caissons, there are many manufacturing and construction limitations. Recently, interlocking caisson systems, which are to form a long caisson by interlocking individual caissons with adjacent caissons, have been much attention. In the present study, a interlocking caisson system with shear-keys was proposed and the wave dispersion effect according to the shear-key was evaluated analytically. As a result, (1) Because of the asymmetric shape of the interlocking caisson, the structure behavior and the wave dispersion effect of one are also asymmetric. (2) The wave dispersion effect is more influenced by the distribution and characteristics of wave acting on each caisson rather than the shape of the shear-key such as shear angle, height, shear length ratio. (3) The interlocking caisson breakwater is almost the same behavior and wave dispersion effect as a fully integrated breakwater.

• Journal of Korean Society of Disaster and Security
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• v.11 no.2
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• pp.69-74
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• 2018

Fog to which environmental impacts are sensitive has a danger to the safety of citizens due to the difficulty in predicting the specific area/time zone. Therefore, we propose a white smoke fog reduction technique using a fog removal device that can remove fog particles directly through dry air and anionic condensation nucleus instead of conventional passive countermeasures. In this study, to verify the effect of reducing fog and the effect of temperature on the white smoke fog which is frequently occurred in the detention basin. As a result, the visible distance of 100m or more was secured within 30 seconds, and it was confirmed that the fog reduction effect is more effective. Also, the lower the temperature, the larger the amount of white smoke fog was. However, the effect of reducing the white smoke fog by temperature was insignificant. Through this experiment, it was possible to verify the reduction effect of the white smoke fog generated in the detention basin through fog removal device.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.84-95
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• 2019

This paper reports the process of seismic fragility analysis for the rahman-type continuous bridge system. The target structure was the five span highway bridge with maximum pier hight of 72m. OpenSees software was used for the nonlinear time history analysis. In this study, 50 ground motions are considered for nonlinear time history analysis. For each ground motion, PGA was scaled from 0.1g to 2.0g with intervals of 0.1g in order to consider a wide range of the seismic intensity measure. In addition, yield displacement and ultimate displacement of each pier were calculated through section analysis. Based on the result of non linear time history analysis and section analysis, damage condition of target bridge was classified according to the definition of damage condition proposed by Barbat et al. As a result, it was predicted that Extensive Damage occurred at P1 when 0.731 g earthquake occurred in the longitudinal direction. Based on the seismic fragility analysis results, it is found that the probability of occurrence of Extensive Damage in the 4,800 - year period earthquake was about 4.2%. Therefore the target bridge has enough safety for earthquake.

• Journal of the HCI Society of Korea
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• v.14 no.2
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• pp.41-47
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• 2019

In this study, a smart assistive device is designed to recognize pedestrian signal and to provide audio instructions for visually impaired people in crossing streets safely. Walking alone is one of the biggest challenges to the visually impaired and it deteriorates their life quality. The proposed device has a camera attached on a pair of glasses which can detect traffic lights, recognize pedestrian signals in real-time using a machine learning algorithm on GPU board and provide audio instructions to the user. For the portability, the dimension of the device is designed to be compact and light but with sufficient battery life. The embedded processor of device is wired to the small camera which is attached on a pair of glasses. Also, on inner part of the leg of the glasses, a bone-conduction speaker is installed which can give audio instructions without blocking external sounds for safety reason. The performance of the proposed device was validated with experiments and it showed 87.0% recall and 100% precision for detecting pedestrian green light, and 94.4% recall and 97.1% precision for detecting pedestrian red light.

• The Journal of Society for e-Business Studies
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• v.24 no.2
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• pp.143-163
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• 2019

The purpose of this study is to identify acceptance factors and influencing factors of respondents' adoption of smart IoT technology to companion animal health based on the integrated technology acceptance model. Based on the previous studies, we constructed the hypotheses by defining the technical factors, social factors, control variables, and mediating variables (UTAUT), and set the hypotheses between the independent variables of each factor and the dependent intention. A research model was designed to verify the relationship between variables. We developed questionnaires on the items and verified them through data collected from 494 people. As a result, product design, quality of service, product performance, and quality service of technological factors had a significant effects on performance expectancy and effort expectancy. However, product safety, product function awareness, and product price did not significantly affect performance expectancy and effort expectancy. Social influence had significant effects on cognitive effect, welfare system, and welfare facilities. In conclusion, the comparative analysis of technical factors and social factors showed that social factors have more significant effects on welfare systems and facilities.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.77-83
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• 2019

With the increase in population, the number of such senior citizens is increasing day by day. These senior citizens have a variety of care needs, but there are not enough health workers to look after them. Ambient Assisted Living (AAL) aims at ensuring the safety and health quality of the older adults and extending the number of years the senior citizens can live independently in an environment of their own preference. AAL provides a system comprising of smart devices, medical sensors, wireless networks, computer and software applications for healthcare monitoring. AAL can be used for various purposes like preventing, curing, and improving wellness and health conditions of older adults. While information security and privacy are critical to providing assurance that users of AAL systems are protected, few studies take into account this feature. In this paper, we propose a secure and lightweight authentication scheme for the AAL systems. The proposed authentication scheme not only supports several important security requirements needed by the AAL systems, but can also withstand various types of attacks. Also, the security analysis results are presented to show the proposed authentication scheme is more secure and efficient rather than existing authentication schemes.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.141-146
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• 2019

Radiation sources used in the field of industrial non-destructive pose a risk of exposure due to ageing equipment and operator carelessness. Thus, the need for a safety management system to trace the location of the source is being added. In this study, Monte Carlo Simulation was performed to analyse the angle dependence of the unit-cell comprising the line-array dosimeter for tracking the location of radiation sources. As a result, the margin of error for the top 10% of each slope was 5.90% at $0^{\circ}$, 8.08% at $30^{\circ}$, and 20.90% at $60^{\circ}$. The ratio of the total absorbed dose was 83.77% at $30^{\circ}$ and 53.36% at $60^{\circ}$ based on $0^{\circ}$(100%) and showed a tendency to decrease with increasing slope. For all gradients, the maximum number was shown at $30^{\circ}$ No. 9 pixels, and for No. 10, there was a tendency to drop 7.24 percent. This study has shown a large amount of angle dependence, and it is estimated that the proper distance between the source and line-array dosimeters should be maintained at a distance of not less than 1 cm to reduce them.

• Journal of Korean Society on Water Environment
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• v.35 no.3
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• pp.224-233
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• 2019

Nitrogen components in liquid manure can reduce safety and quality of environment harmfully. To minimize the environmental risks of manure, understanding fate of manure in environment is necessary. This study aimed at investigating applicability of a simplified Level III fugacity model for simulating $NH_3-N$ component to analyze environmental fate and transport of $NH_3-N$ in liquid manure and to provide basis for improving management of N in the liquid manure system and for minimizing the environmental impacts of N. The model simulation conducted for four environmental compartments (air, water, soil, and rice plants) during rice-cropping to trace $NH_3-N$ component and provided applicability of the Level III fugacity model in studying the environmental fate of $NH_3-N$ in manure. Most of $NH_3-N$ was found in water body and in rice plants depending upon the physicochemical properties and proper removal processes. For more precise model results, the model is needed to modify with the detailed removal processes in each compartment and to collect proper and accurate information for input parameters. Further study should be about simulations of various N-typed fertilizers to compare with the liquid manure based on a modified and relatively simplified Level III fugacity model.