• 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.

• Journal of Navigation and Port Research
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• v.47 no.1
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• pp.10-17
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• 2023

A series of studies on the development of autonomous surface ships have been promoted in domestic and foreign countries. One of the main technologies for the development of autonomous ships is path-following control, which is closely related to securing the safety of ships at sea. In this regard, the path-following performance of an autonomous ship should be first evaluated at the design stage. The main aim of this study was to develop a visual and quantitative evaluation method for the path-following control performance of an autonomous ship at the design stage. This evaluation technique was developed using a computational fluid dynamics (CFD)-based path-following control model together with a line-of-sight (LOS) guidance algorithm. CFD software was utilized to visualize waves around the ship, performing path-following control for visual evaluation. In addition, a quantitative evaluation was carried out using the difference between the desired and estimated yaw angles, as well as the distance difference between the planned and estimated trajectories. The results demonstrated that the ship experienced large deviations from the planned path near the waypoints while changing its course. It was also found that the fluid phenomena around the ship could be easily identified by visualizing the flow generated by the ship. It is expected that the evaluation method proposed in this study will contribute to the visual and quantitative evaluation of the path-following performance of autonomous ships at the design stage.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.608-616
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• 2021

Purpose: Safety inspections by existing personnel have been limited in evaluation and data securing due to concerns about the safety of technicians or difficulty in accessing them, and are becoming a bigger problem as the number of maintenance targets increases due to the aging of facilities. As drone technology develops, it is possible to ensure the safety of personnel, secure visual data, and diagnose quickly, and use it is increasing as safety inspection of facilities by drones was introduced recently. In order to further enhance utilization, it is considered necessary to base a consideration standard for facility appearance investigation by drones, and in this paper, research was conducted on dams. Method: To calculate the quality, existing domestic safety inspection and drone-related consideration standards were investigated, and procedures related to safety inspection using drones were compared and analyzed to review work procedures and construction types. In addition, empirical data were collected through drone photography and elevation image production for the actual dam. Result: Work types for safety inspection of facilities using drones were derived, and empirical survey results were collected for two dams according to work types. The existing guidelines were applied for the adjustment ratios for each structural type and standard of the facility, and if a meteorological reference point survey was necessary, the unmanned aerial vehicle survey of the construction work standard was applied. Conclusion: The finer the GSD in appearance investigation using drones, the greater the number of photographs taken, and the concept of adjustment cost was applied as a correction to calculate the consideration standard. In addition, it was found that the problem of maximum GSD indicating limitations should be considered in order to maintain the safe distance.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.43-57
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• 2022

In this paper, we propose a method of analyzing research papers published by researchers belonging to university departments in the field of disaster & safety for the scientometric analysis of the research status in the field of disaster safety. In order to conduct analysis research, the dataset constructed in previous studies was newly improved and utilized. In detail, for research papers of authors belonging to the disaster prevention and safety engineering type department of domestic universities, institution identification, cited journal identification of references, department type classification, disaster safety type classification, researcher major information, KSIC(Korean Standard Industrial Classification) mapping information was reflected in the experimental data. The proposed method has a difference from previous studies in the field of disaster & safety and data set based on related keyword searches. As a result of the analysis, the type and regional distribution of organizations belonging to the department of disaster prevention and safety engineering, the composition of co-authored department types, the researchers' majors, the status of disaster safety types and standard industry classification, the status of citations in academic journals, and major keywords were identified in detail. In addition, various co-occurrence networks were created and visualized for each analysis unit to identify key connections. The research results will be used to identify and recommend major organizations and information by disaster type for the establishment of an intelligent crisis warning system. In order to provide comprehensive and constant analysis information in the future, it is necessary to expand the analysis scope and automate the identification and classification process for data set construction.

• Computational Structural Engineering
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• v.7 no.3
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• pp.95-103
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• 1994

The safety related components in the nuclear power plant should be designed to withstand the seismic load. Among these components the integrity of reactor internals under earthquake load is important in stand points of safety and economics, because these are classified to Seismic Class I components. So far the modelling methods of reactor internals have been investigated by many authors. In this paper, the dynamic behaviour of reactor internals of Yong Gwang 1&2 nuclear power plants under SSE(Safe Shutdown Earthquake) load is analyzed by using of the simpled Global Beam Model. For this, as a first step, the characteristic analysis of reactor internal components are performed by using of the finite element code ANSYS. And the Global Beam Model for reactor internals which includes beam elements, nonlinear impact springs which have gaps in upper and lower positions, and hydrodynamical couplings which simulate the fluid-filled cylinders of reactor vessel and core barrel structures is established. And for the exciting external force the response spectrum which is applied to reactor support is converted to the time history input. With this excitation and the model the dynamic behaviour of reactor internals is obtained. As the results, the structural integrity of reactor internal components under seismic excitation is verified and the input for the detailed duel assembly series model could be obtained. And the simplicity and effectiveness of Global Beam Model and the economics of the explicit Runge-Kutta-Gills algorithm in impact problem of high frequency interface components are confirmed.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.1-6
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• 2017

Visual evaluation of chest radiograph images is the most practical and effective method. This study compared the Body Mass Index, waist circumference, and mAs with chest radiographs of 351 women. The Bureau of Radiological Health method was used to evaluate the image quality of chest X-ray images by anatomical and physical methods. The average age of the subjects was $30.17{\pm}4.73$ and the average waist circumference was $66.91{\pm}4.67cm$. The mean Body Mass Index value was $20.21{\pm}2.23$, the mean value of mAs was $3.04{\pm}0.78$, and the mean value of Bureau of Radiological Health was $79.83{\pm}8.45$. When the Body Mass Index value increased, waist circumference and mAs mean value increased. The mean value of Body Mass Index was statistically significant(p<0.05) in Group 4 compared to Groups 1 and 2, with increasing Body Mass Index. Exposure control of the automatic exposure control system is considered to be well performed according to body thickness or Body Mass Index at the time of chest radiography. As the Body Mass Index increases, the thickness of the body increases and the breast thickness of the woman also increases. Therefore, it is considered that the exposure amount is changed by the automatic exposure control device to affect the image quality.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5D
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• pp.445-451
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• 2012

Visual changes and speed changes in curved sections of highways are more dangerous than straight sections According to the enquetes conducted by Coalition for Transportation Culture in 1999, about 78% of drivers are dissatisfied with traffic guide and safety signs, with lack of visibility being the largest reason with about 27.9% of respondents indicating it as reason for dissatisfaction. In particular, the lack of visibility during nighttime or bad weather not only threatens driver safety due to poor delivery of information, but also affects the service level of highways. Because of this a new delineation must be installed and managed to enhance driver visibility. In this research, an optimal delineation system to enhance traffic safety is presented. In this research drivers effectively obtained information on highway alignment on the curved sections using a retro-reflection type delineation system and a newly-developed internal lighting delineation system to improve safety on the highways. A statistical comparison was conducted and analysis was done for the delineation systems that enhanced visibility through primary and secondary enquaetes. As a result, inside-lighting delineator will be selected in terms of safety at the curve sections. The inside-lighting delineator was more effective than the retro-reflection delineator on visibility, the necessity of reduction of speed and will reduce the hazard at curve sections. It is anticipated that when a delineation system based on this research is installed, a reduction in the number the number and severity of traffic accidents on curved sections will be reduced. In addition this system will more effectively provide drivers with information about highway alignment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.403-412
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• 2011

On a curve radius, there is speed deviation because a driver who is on the curve radius can have visual distortion. The curve radius can be more dangerous than a straight radius by many reasons. Especially, visibility paralysis of delineator that is because of night and bad weather. Can pervert the information about curve sections, it threatens safety. More over accident risk is increased by influence to travel speed. Therefore, it needs to build and control delineators for driver's visibility. Therefore, this study focus on finding the two types of delineator(the retro-reflection and inside-lighting delineator) by insight-surveying and the operating speed are compared by survey and operating speed. Finally, inside-lighting delineator will be selected in terms of safety at the curve sections. The inside-lighting delineator was more effective than the retro-reflection delineator on visibility, the necessity of reduction of speed and will reduce the hazard at curve sections. Also, the study analyzes safety is guaranteed by the slight reduction of speed when the driver enters a curve radius with inside-lighting delineator. As a result, the inside-lighting delineator can give the information about horizontal and vertical profile effectively, so it can reduce the accident risk. And it can use to improve traffic safety on curve radius.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.11 no.3
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• pp.207-212
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• 2013

Since the Fukushima nuclear power plant accident in March 2011, critical views on the increase in operation of nuclear power plants including the safety and the economic feasibility thereof have been expanding across the world. In these circumstances, we are to find out solutions to the controversial questions on whether nuclear power plants are economically more feasible than other energy sources, while the safety thereof is fully maintained. Thereby, nuclear power plants will play a key role as a sustainable energy source in the future as well as at present. To measure the social safety level that Korean people are actually feeling after the Fukushima accident, a method of cost-benefit analysis called the Contingent Valuation Method(CVM) was used, whereby we wanted to estimate the amount of expenses the general public would be willing to pay for the safety based on their acceptance rather than the social safety. As a result of calculating the trade-off value of the economic feasibility versus the safety in nuclear power plants through the survey thereon, it caused the nuclear power generation cost to be increased by 4.75 won/kWh. Reflecting this on the current power generation cost of 39.11 won/kWh would increase the cost to 43.86 won/kWh. It is thought that this potential cost is still more competitive than the coal-fired power generation cost of 67 won/kWh. This result will be available as a basic data for the 2nd Energy Basic Plan to be drawn up this year, presenting policy implications at the same time.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2003.11a
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• pp.84-90
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• 2003

최근 견관절 질환 치료의 발전에 힘입어 술 후의 유병율을 줄이고, 보다 견고한 조직 복원이 가능해 짐으로써 운동사슬(kinetic chain)의 생리적이고 생 역학적인 복원을 위한 재활치료를 조기에 시행할 수 있게 되었다. 이러한 조기재활 치료는 술 전 적절한 준비, 해부학적인 수술적 치료, 술 중 적절한 운동범위의 회복, 술 후 조기 보조 및 능동 보조운동, closed chain-axial loading rehabilitation protocol, 재활치료 중 기능적 관절위치 유지 및 기능회복에 따른 생리적 호전 등의 원칙을 통해 견관절의 여러 질환의 재활치료에 적용할 수 있다. 견관절의 조기 재활치료 시 통증은 근육의 조화운동을 저해하게 되며 관절의 안정적인 운동과 기능을 방해하게 된다. 따라서 시각 측정표를 이용한 4이하의 통증범위에서, 관절의 위치와 팔 및 몸의 운동 그리고 근육의 작용을 잘 관찰하는 가운데 운동을 함으로써 통증으로 인한 근억제 효과를 줄이며, 보다 조기에 안전하게 일상생활 및 운동복귀를 할 수 있다.