• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.23-31
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• 2018

Recently, there was an collision accident of vehicle-concrete median barrier and unfortunately, passengers were killed by exceeded capacity of concrete median. Therefore, improving the capacity of concrete median barrier is need to reduce damage. Accordingly, in this study, appropriate collision model verified by using the FE analysis program LS-Dyna and recommend a concrete median barrier section. The improvement parameters such as wire mesh diameter, steel plate, rubber pad were selected for improved capacity of the median barrier. Finally, section of concrete median barrier improved wire mesh diameter decreased volume loss, section of concrete median barrier improved rubber pad accepted impact loading and increased elastic area.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.10
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• pp.1-10
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• 2000

A rigorous modeling of ultra-low energy implantation is becoming increasingly more important as devices shrink to deep submicron dimensions. In this paper, we have developed an efficient three-dimensional Monte Carlo ion implantation model based on a modified Binary Collision Approximation(BCA). To this purpose, the modified electronic stopping model and the multi-body collision model have been taken into account in this simulator. The dopant and damage profiles show very good agreement with SIMS(Secondary Ion Mass Spectroscopy) data and RBS(Rutherford Backscattering Spectroscopy) data, respectively. Moreover, the ion distribution replica method has been implemented into the model to get a computational efficiency in a 3D simulation, and we have calculated the 3D Monte Carlo simulation into the topographically complex structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.205-213
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• 2019

In the Pohang Earthquake in 2017, considerable damage to non-structural elements, such as ceiling systems, exterior finishes, and curtain walls, was reported; thus, the seismic designs of non-structural elements are important. In this study, the modal characteristics of a ceiling system were investigated through the impact hammer test. The frequency and damping ratio according to the length of the hanger bolt were identified. In addition, collision experiments were conducted to obtain the impact duration for exactly considering the impact effects of the ceiling against a wall or other adjacent elements. Based on the identified dynamics and impact duration of the ceiling system, the seismic responses of the ceiling system were obtained numerically in case of collision. Numerical simulation results show that the impact load tends to increase with the clearance between the ceiling and adjacent elements, and is not correlated with the length of the hanger bolt.

• Journal of Auto-vehicle Safety Association
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• v.13 no.3
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• pp.78-85
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• 2021

Recently a traffic accident of heavy duty vehicles under the mandatory installation of ADAS (Advanced Driver Assistance System) is often reported in the media. Heavy duty vehicle accidents are normally occurring a high number of passenger's injury. According to report of Insurance Institute for Highway Safety, FCW (Forward Collision Warning) and AEB (Automatic Emergency Braking) were associated with a statistically significant 12% reduction in the rate of police-reportable crashes per vehicle miles traveled, and a significant 41% reduction in the rear-end crash rate of large trucks. Also many countries around the world, including Korea, are studying the effects of ADAS installation on accident reduction. Traffic accident statistics of passenger vehicle for business purpose in TMACS (Traffic safety information Management Complex System in Korea) tends to remarkably reduce the number of deaths due to the accident (2017(211), 2018(170), 2019(139)), but the number of traffic accidents (2017(8,939), 2018(9,181), 2019(10,095)) increases. In this paper, it is introduced a traffic accident case that could lead to high injury traffic accidents by being equipped with AEB in a bus. AEB reduces accidents and damage in general but malfunction of AEB could occur severe accident. Therefore, proper education is required to use AEB system, simply instead of focusing on developing and installing AEB to prevent traffic accidents. Traffic accident of AEB equipped vehicle may arise a new dispute between a driver's fault and vehicle defect. It is highly recommended to regulate an advanced event data recorder system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.542-549
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• 2019

Maritime accidents, such as the collision of a fishing boat in Incheon's Yeongheung Island, result in several casualties and property damage, even if they occur just once. To prevent such accidents, the Incheon Metropolitan Government is implementing safety management policies; further, they will provide ship collision warning services to prevent collisions on WAVE (Wireless Access in Vehicular Environment) communication-based ship safety operation pilot projects. However, to realize these objectives, a service standardization method is required that defines specific service types, configurations, and systems, which should be prepared based on user requirement analyses. In this study, a standardization method of WAVE communication-based collision warning service was developed by analyzing the requirements of the vessel operators subject to the services and related authorities. This will help improve the quality of service, ensuring professionalism and reliability through continuous improvement and efforts for standardization, as well as data derived from demonstration projects. Therefore, it is expected to help prevent maritime accidents to a considerable extent.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.92-100
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• 2015

The aim of this study is to evaluate the fracture characteristics of ductile fiber reinforced cement based composites with 1.5 volume ratio of polyvinyl alcohol and steel fiber by high velocity impact of steel projectile. We used gunpowder impact facility to evaluate the fracture characteristics of ductile fiber reinforced cement based composites by collision of steel projectile, and the impact velocity was from about 150 to 1,000m/s. The results of evaluation on the fracture characteristics of ductile fiber reinforced cement based composites were penetration grade, which is the kinetic energy more than three times of no-fiber reinforced specimen (Plain). In addition, ductile fiber reinforced cement based composites did not occurred critical damage other than the debris. In the case of mass loss, Plain specimen was proportional to kinetic energy of steel projectile, while ductile fiber reinforced cement based composites was not significantly affected by kinetic energy of steel projectile. In particular, this tendency had a close relationship with the fracture characteristics of back side of specimens, and the scabbing inhibiting efficiency of PVA specimen was higher than S specimen. In the results of verifying relationship between front and back side calculated by local damage, scabbing occurred at the region close to the back side in the ductile fiber reinforced cement based composites unlike Plain specimen. Thus, in this study, we examined principal fracture behaviors of ductile fiber reinforced cement based composites under collision of steel projectile, and verified that impact resistance performance was improved as compared to Plain specimen.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.851-856
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• 2012

There has been increasing the possibility of occurring the marine accident and become bigger the extent of damage with the growing number and high speed of ships. Also, there were tremendous loss of lives and properties in accidents of Hebei spirit in 2007 and Cheon Ahan war ship in 2010 with the insufficient salvage response and the lack of emergency response systems. When a ship has suffered an incident, the best way of preventing damage or pollution from its progressive deterioration would be to providing a place of refuge and to repair the damage rapidly. Therefore, it was examined the recent collision accident broken out near the Nam-Hae, and then suggested that it was necessary to be improved of the domestic salvage systems. It requires the procedures of providing a place of refuge, and the towing support system which make the damaged ship moved to the safe area, and joining of the ISU.

• Fire Science and Engineering
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• v.30 no.1
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• pp.130-137
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• 2016

The purpose of this study is to investigate the circumstances surrounding collisions involving ambulances with an aim to improving the safe operation of emergency services. Collisions are relatively common within paramedic emergency services. We analyzed the time, injury site, and any other specific factors of 908 collisions occurring within four cities. Within our study 29.6% of paramedics have been involved in accidents while responding to an emergency call, with the main cause of the accident being signal violation (35.7%), and is the other party's negligence (22.2%). 92.1% of these accidents occurred while the emergency lights were being operated. XX% of accidents took place in the afternoon, while xx% took place within the hours of xx:xx and xx:xx, during which time there is generally lower levels of traffic, which can cause severe brain and neck damage of 14.4% but the other part is 62.1%. (Ed note; this is not clear at all. 14.4% of collisions resulted in severe head and neck injuries, while 23.5% of collisions resulted in no injury. According to the respondents, defensive driving (xx%), observance of traffic laws (xx%), safe driving habits (xx%)to paramedics were the most critical factors in evading collision. Signal passes were identified as the most common cause of collision (70.1%). Although the majority of collisions occurred while the emergency lights were operational, the damage can cause severe damage at the time of accident occurred.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.125-136
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• 2017

This study investigated the performance of a steel column standing on a reinforced concrete footing when it was subjected to collision of an eight-ton single unit truck. Finite element analyses of the structure with different connection schemes were performed using the finite element model of the truck, and the results showed that the behavior of the column subjected to the automobile impact depended largely on the column-footing connection detail. Various reinforcement schemes were investigated to mitigate the damage caused by the car impact. The probability of the model reinforced with a certain scheme to reach a given limit state was obtained by fragility analysis, and the effects of the combined reinforcement methods were investigated based on the equivalent fragility scheme. The analysis results showed that the reinforcement schemes such as increase of the pedestal area, decrease of the pedestal height, and the steel plate jacketing of the pedestal were effective in reducing the damage. As the speed of the automobile increased the contribution of the increase in the number of the anchor bolts and the dowel bars became more important to prevent crushing of the pedestal.

• Journal of Power System Engineering
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• v.12 no.4
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• pp.64-71
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• 2008

This study is on pedestrian protection device using pneumatic cylinder and simple link mechanism when vehicle collide with pedestrian. This study ensured the safety space between engine and hood after it applies to simple link mechanism and pneumatic cylinder. It can absorb the damage which measure the specific device if vehicle collide with pedestrian. Combination of simple link mechanism and pneumatic cylinder was more superior than the present pedestrian protection device. Simple link mechanism could confirm superior height and survival probability than when only cylinder operated. It also ensured enough space between engine and hood. And if a cylinder is not working because of old cylinder, poor repair or damage of accident vertical cylinder would be difficult to execute because there exists the irregular space between engine and hood. If simple link mechanism operates with only one cylinder it could ensure the regular space because simple link mechanism set up at the middle of hood. So this device could confirm high safety for pedestrian.