• Journal of the Korea Concrete Institute
• /
• v.28 no.6
• /
• pp.673-683
• /
• 2016

In recent years, frequent terror or military attack by explosion, impact, fire accidents have occurred. Particularly, World Trade Center collapse and US Department of Defense Pentagon attack on Sept. 11 of 2001. Also, nuclear power plant incident on Mar. 11 of 2011. These attacks and incidents were raised public concerns and anxiety of potential terrorist attacks on major infrastructures and structures. Therefore, the extreme loading researches were performed of prestressed concrete (PSC) member, which widely used for nuclear containment vessel and gas tank. In this paper, to evaluate the blast resistance capacity and its protective performance of bi-directional unbonded prestressed concrete member, blast tests were carried out on $1,400{\times}1,000{\times}300mm$ for reinforced concrete (RC), prestressed concrete without rebar (PSC), prestressed concrete with rebar (PSRC) specimens. The applied blast load was generated by the detonation of 55 lbs ANFO explosive charge at 1.0 m standoff distance. The data acquisitions not only included blast waves of incident pressure, reflected pressure, and impulse, but also included displacement, acceleration, and strains at steel, concrete, PS tendon. The results can be used as basic research references for related research areas, which include protective design and blast simulation under blast loading.

• Journal of Navigation and Port Research
• /
• v.31 no.3 s.119
• /
• pp.213-221
• /
• 2007

Recently, environmental design are becoming a matter of grave concern in shipbuilding. Out of these concern, oil spilt which is induced by grounding accidents is very critical reason of the ocean pollution. Therefore, a series qf quarter of 105k tanker model grounding simulations were conducted to analyze it's characteristics for the accident. ship get using LS-DYNA3D. In this paper, to conduct whole simulations, a meshsize convergence test was carried out to determine appropriate meshsize for grounding test. After the series analysis. These results were analyzed as each case.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.6
• /
• pp.600-606
• /
• 2016

Seafarers are often placed in circumstances that require emergency evacuations due to various causes, including ship collisions, sinking, stranding, and fires. Achieving shorter evacuation time is an important factor in increasing the survival rate during these circumstances, but the narrow and complicated structure of ships is an obstacle when it comes to executing a quick evacuation. Also, unpredictable restrictions may be imposed by bad sea or weather. In this study, various experiments were conducted with sailors currently on board ships in order to examine factors that increase evacuation time. The data was then and analyzed. Evacuation time was measured by dividing crews into groups: sailors that were given an explanation of the ship's structure and those that were not. Furthermore, the visibility range was divided into 0 m, 3 m, and 5 m. The results indicated that, having an explanation of the ship structure did not have much of an effect on evacuation time but visibility conditions led to an increase in evacuation time with a maximum of 2.5 to 2.6 times longer when the visible distance was 5 m, 0 m and 3 m. Therefore, ensuring a visible distance of over 5 m was determined to be the most important factor for reducing evacuation time. In the future, effort should be made to ensure a greater visible distance to improve the survival rate of seafarers and passengers on board ships that encounter incidents.

• Journal of the Korean Society for Railway
• /
• v.20 no.4
• /
• pp.458-465
• /
• 2017

The railway signaling system, which controls the course of trains and the distance between trains, is a safety critical system of the railway system because derailment or collision of trains can occur if unsafe failure is generated by any fault. The international standards of reliability, availability, maintainability, and safety of railway applications require that the safety of functions be guaranteed in safety critical systems; system reliability and safety are quantitatively estimated and demonstrated by the failure rates of devices. The development of technology has accelerated the development of railway signaling systems. Existing devices, which have already been verified as to their safety, are applied with special user requirements to reflect the new operation scenario. It is found that the reliability and safety of the devices are different depending on individual application. Therefore, the reliability of the railway signaling system must be considered while complying with the international standards; this requires that the initial failure rate be estimated and demonstrated using fault data gathered over several years. This paper shows a method for demonstrating the initial estimated failure rate and suggests a fault data collection method and an overall process that is based on probability.

• Korean Journal of Occupational Therapy
• /
• v.26 no.4
• /
• pp.127-143
• /
• 2018

Objective : The purpose of this study was to compare with the effects of driving simulator and Dynavision training after stroke through the test of cognitive ability and driving performance. Methods : Twenty-one stroke patients were randomly classified to the driving simulator training group (N=11) and Dynavision training group (N=10), and were carried out respectively training for 15 times. The driving performances was measured by the driving simulator test, and cognitive-perceptive abilities was measured by the DriveABLE Cognitive Assessment Tool, Trail Making Test-A, Trail Making Test-B and Mini Mental State Examination-K. Results : The driving simulator training group showed significant changes in all cognitive tests and most of driving performances. The Dynavision training group also showed significant changes in all cognitive tests except for Trail Making Test-A and some driving performances. The significant differences on both groups were found regarding the estimated degree of results on the on-road evaluation, the number of off road accidents and collisions. In addition, the causal influence of the two training methods on these variables was analyzed to be more than 20%. Conclusion : The driving simulator and Dynavision training were found to be effective intervention in the driving rehabilitation after stroke. In particular, it was confirmed that the driving simulator is an effective training to improve overall driving ability of stroke patients. In addition, the difference in training effect between the two training methods was found to be more than 20%.