• Proceedings of the KSME Conference
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• 2007.05a
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• pp.718-723
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• 2007

A three dimensional multibody modeling of a launcher system was developed and dynamic characteristics of the system was carried out. All the components were modeled as rigid bodies, All the components of system, ie; chassis, turret, cage and suspension parts, are modeled as rigid. The force interaction between the ground and tire was modeled as a point contact model. The factors were selected as cause and effect diagram of the MINITAB. To see effect of the stiffness, damping, mass at the launcher system, several cases of suspension parameters were compared and optimal values were selected. The stiffness and the damping coefficient were selected as design variables to minimize the required time for the next fire. The dynamic simulation was carried out using the ADAMS, and the MINITAB was employed for data analysis.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.306-311
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• 2015

Recently, vessel hijacking by pirates has been a big issue around the world. In case of the hostages of M/V "SAMHO Jewelry" on January 20, 2011, the Korean Navy has rescued 21 seafarers by first naval operation with somalia pirates since establishment of the Navy. Also, in case of the "HANJIN Tianjin", all crews evacuated to the Citadel promptly when being attacking by pirates and were safely rescued by the navy. By the accident, Necessity of Citadel for seafarer on board ship came to the fore against pirates. Taking in account increasing pirates accident at sea, many research relating to pirates has been implementing with a view to responding to them so far. By amending the ship facility regulation in the domestic law on Jan. 2011, the installment of Citadel on board ship became mandatory for ocean going vessel serving pirates area. Hence, this paper provides new model of Citadel structure based on an Fire Dynamic simulation in order to improve personal safety in case of vessel hijacking.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.229-236
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• 2016

For this research, the trajectory of a projectile was simulated via the multibody dynamics analysis of a self-propelled mortar. The dynamic model was composed of a mortar model and a vehicle model, and was simulated using the RecurDyn program. Interior ballistic was applied to the mortar model, and exterior ballistic was conducted by Matlab using the simulation results of the interior trajectory. Through repetitive Monte-Carlo simulations, the accuracy of the mortar was analyzed by considering variations in the aiming angle and vehicle dynamic response.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.850-852
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• 1996

High impedance fault (HIF) is defined as fault that general overcurrent relay can't detect or interrupt, Especially when HIF occur under 15 kV, energized high voltage conductor results in fire hazard, equipment damage or personal threat. Because most HIF occur arc, HIF detection using arc is to increase. Numerical arc model can be applied in an electromagnetic transients program (EMTP) to reproduce the dynamic and random characteristic of arcs for any insulator arrangement, current and system voltage. It allows the representation of any network configuration to be investigated, so the digital simulation of arc faults through air can be substitute for demanding power arc test.

• Fire Science and Engineering
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• v.22 no.3
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• pp.221-227
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• 2008

In this study, the fire suppression characteristics of a water mist with natural wind in a road tunnel were calculated using the FDS(Fire Dynamic Simulation) code. In addition, the cooling and the chemical kinetic effects of water vapor on fire extinction ere investigated in a counterflow non-premixed flame using a detailed chemistry. As a result, the behavior of fire plume and the spray characteristics of water mist are modified remarkably with the increasing of wind velocity. In the case which is not the external natural wind, small droplets are more efficient in fire suppression than large droplets. However, the large droplets show better results on the fire suppression than the small droplets with the increasing of wind velocity. It can be estimated that the natural wind disturb the penetration of water droplets into the flame region and decrease the effect of oxygen dilution. Finally, it can be identified that the fire into the natural wind can be suppressed with smaller amount of $H_2O$ by flame stretching effect in the flame region than one in an enclosure, and the chemical kinetic effects of $H_2O$ on fire extinction are not affected significantly the velocity of natural wind.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.4
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• pp.153-161
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• 2017

Liquid storage tank is one of the major infrastructures and generally used to store gases, drinking and utilizing water, dangerous fluids, fire water and so on. According to the recent reports and experiences, the tank structures are damaged in many earthquakes due to their low energy dissipating capacity. Therefore, many researchers have been tried to know the dynamic properties of the tanks including liquids. However, vary limited experimental studies are carried out using relatively small tank models. In this study, a series of shaking table tests are performed with maximum 2 m cubic rectangular liquid storage tanks made of steel to measure the natural frequency and estimate damping coefficient of impulsive and convective mode of the tanks. Especially, the damping values under different shapes and excitation methods are estimated by logarithmic decrement method and half power band-pass method and compared with current design code and standards such as ASCE 7, Eurocode 8 and NZS. Test results show that the impulsive mode damping is around 2% which is proposed by general standards and codes but the impulsive mode damping is 0.13% average that is slightly lower than the code recommendation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.689-695
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• 2015

The offshore plant crews that were commissioned in the commercial startup phase boarded the offshore plant in two shifts until the end of the project. The crews who were hired by the owner side stayed in the original offshore plant during the project. However, most of the offshore plant commissioned members who were dispatched from the shipyard were accommodated in the offshore accommodation barge. For this reason, they were exposed to many accidents since there are a lot of people staying in a small space. This study suggested a method for improving survival rate at offshore accommodation barge in terms of life safety. It is assumed that the fire accident among unfortunate events which take place in the offshore accommodation barge mainly occurred. So, this study analyzed the safety evacuation for offshore plant employees using fire simulation model based on both domestic and international law criteria. In particular, When fire occurs in the offshore accommodation barge, the periodically well trained crews are followed safety evacuation procedure. whereas many employees who have different background such as various occupations, cultural differences, races and nationality can be commissioned with improper evacuation behaviors. As a result, the risk will be greater than normal situation due to these inappropriate behaviors. Therefore, This study analyzed the Required Safe Escape Time (RSET) and Available Safe Escape Time (ASET). Also it was suggested the improvement of structure design and additional arrangement of safety equipment to improve the survival rate of the residents in offshore accommodation barge.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.3
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• pp.171-176
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• 2016

In this paper, we consider a regulation problem of nonlinear systems under two triangular conditions where there possibly exist unbounded parameters in the systems. We propose a state feedback controller with dynamic gains in order to deal with unbounded parameters based on the condition of the time-varying rate of the growing parameter. The analysis of our control scheme is carried out by Lyapunov stability method. Our control method is verified by simulation results.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.491-495
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• 2016

We deal with the regulation problem of nonlinear systems with time-varying delays in both the states and input. A new state feedback controller with dynamic gains is developed based on matrix inequality and non-predictor methods. The proposed control scheme is analyzed using the Razumikhin theorem, and its effectiveness is demonstrated with simulation results.

• Journal of the Semiconductor & Display Technology
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• v.17 no.3
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• pp.1-9
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• 2018

The drone has the restrictions on the controls, the battery and the surrounding environment in performing missions such as fire extinguishing. This restriction can improve the limitations that leave the leader can be monitored. The existing method of constructing the leader based on the GPS is highly dependent on the signal and is vulnerable to hardware defects. In this paper, we solve these problems with dynamic leaders decision. Drones can use their leader drones rather than remote controls. Information about the drones changes depending on the surrounding environment by replacing the leader with a dead battery or electing leader by the drones themselves without human intervention. This suggests that the leader monitors the community through a framework for continuing the drones collaboration and that the community can collaborate to overcome the limitations and continue the mission. The analysis of the proposed system through simulation experiments confirm that it has a better task performance. By using this system, it is possible to continue the mission and solve problems that are vulnerable to hardware defects.