• Journal of Korean Society of Transportation
• /
• v.14 no.4
• /
• pp.77-90
• /
• 1996

Recently existing the road traffic low is requlated by hump standard, which is established throuth the actual england TRRL(Transpodt and Road Research Laboratory) experiment. The determined standard has been utilized, however, wihtout the test on of our street and its drivers driving characteristics. Even with the utilization, the appropriate before and after management, is not constituted. In Spite of minimum speed limit, in many case, the utilization itself is questionalble rather than the purpose of restraining speed limit or reducing vehicle confacts. Along with hump consideration, social attention is focused due to series of personal law suit(traffic accident) field against the negligence of local organization management. Therefore counter measure of safe transportation facility is urgently required. With consideration of above background, the purpose of this research is to develop the hump that is appropriate with our transportation environment. This can be achieved thr ugh analysis of hump effectiveness, examination of drivers awamess, facilitation/management problems, and various problems in verticle acceleration.

• Geomechanics and Engineering
• /
• v.9 no.2
• /
• pp.125-144
• /
• 2015

This paper presents the probabilistic seismic microzonation of densely populated Kolkata city, situated on the world's largest delta island with very soft alluvial soil deposit. At first probabilistic seismic hazard analysis of Kolkata city was carried out at bedrock level and then ground motion amplification due to sedimentary deposit was computed using one dimensional (1D) wave propagation analysis SHAKE2000. Different maps like fundamental frequency, amplification at fundamental frequency, peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), maximum response spectral acceleration at different time period bands are developed for variety of end users, structural and geotechnical engineers, land use planners, emergency managers and awareness of general public. The probabilistically predicted PGA at bedrock level is 0.12 g for 50% exceedance in 50 years and maximum PGA at surface level it varies from 0.095 g to 0.18 g for same probability of exceedance. The scenario of simulated ground motion revealed that Kolkata city is very much prone to damage during earthquake.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1995.10a
• /
• pp.258-265
• /
• 1995

For design of seismic isolated system the determination of isolated frequency is very important. In this paper the effects of seismic isolated frequency for cylindrical tank are investigated using the 1940 EL Centre earthquake(NS). From the results of analysis the seismic isolated frequencies significantly depend on input acceleration and displacement components in lower frequency regions. Therefore, the seismic isolated frequency should be determined by consideration of input ground motion characteristics. For the seismic analysis the modified hysteretic hi-linear model of seismic isolators which can consider the yield load variation, shape of hysterisis loop variation and hardening effects of isolators is proposed. The analyses using the proposed model give similar displacement responses but higher maximum acceleration responses than those using the simple hysteretic hi-linear model.

• International Journal of Aerospace System Engineering
• /
• v.4 no.2
• /
• pp.5-9
• /
• 2017

In a pressurized fuel supply system of aircraft, a flow passage opening device is required to keep fuel continuously transferred from one tank to the other. The device utilizes balancing weights in order to follow up an acceleration at special conditions such as negative g. It is very difficult to test the device in a real high-speed and high-altitude test since severe test conditions and expensive supports are needed. Therefore, this paper deals with performance analysis of a flow passage opening device through low speed aircraft captive flight tests (CFT) including roll and negative-g maneuvers. It is shown that balancing weights in the device can open the passage in accordance with fuel position.

• Smart Structures and Systems
• /
• v.8 no.2
• /
• pp.157-172
• /
• 2011

A new method for both local damage(s) identification and input excitation force identification of beam structures is presented using the dynamic response sensitivity-based finite element model updating method. The state-space approach is used to calculate both the structural dynamic responses and the responses sensitivities with respect to structural physical parameters such as elemental flexural rigidity and with respect to the force parameters as well. The sensitivities of displacement and acceleration responses with respect to structural physical parameters are calculated in time domain and compared to those by using Newmark method in the forward analysis. In the inverse analysis, both the input excitation force and the local damage are identified from only several acceleration measurements. Local damages and the input excitation force are identified in a gradient-based model updating method based on dynamic response sensitivity. Both computation simulations and the laboratory work illustrate the effectiveness and robustness of the proposed method.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.6
• /
• pp.608-613
• /
• 2006

Any input acceleration that bends RLG dithering axis causes flexure error, which is a source of the noncommutative error that can not be compensated by simply using integrated gyro sensor output. This paper introduces noncommutative error equations that define attitude errors caused by flexure errors. In this paper, flexure error is classified as sensor level error if the sensing axis coincides with the dithering axis and as system level error if the two axes do not coincide. The relationship between gyro output and the rotation vector is introduced and is used to define the coordinate transformation matrix and angular motion. Equations are derived for both sensor level and system level flexure error analysis. These equations show that RLG based INS attitude error caused by flexure is directly proportional to time, amount of input acceleration and the dynamic frequency of the vehicle.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.454-459
• /
• 2006

A wheel force becomes large as increasing the stiffness of rail-pad, and it accelerates the deterioration of track, and it leads the maintenance cost rising. So, it is required to determine an appropriate replacement period for rail-pad. As a preliminary study to determine it, a numerical analysis was conducted to investigate the influence on a track behavior by the hardening of rail-pad. From the analysis, one knows that the dynamic wheel force is vary depend on the stiffness of rail-pad and the running speed of vehicle, the displacement and acceleration of rail is decreasing as increasing stiffness of rail-pad, and the displacement and acceleration increased in proportion to the rail-pad stiffness increasing.

• Proceedings of the KAIS Fall Conference
• /
• 2004.11a
• /
• pp.203-205
• /
• 2004

A soft error rate neutrons is a growing problem for terrestrial integrated circuits with technology scaling. In the acceleration test with high-density neutron beam, a latch-up prohibits accurate estimations of the soft error rate (SER). This paper presents results of analysis for the latch-up characteristics in the circumstance corresponding to the acceleration SER test for SRAM. Simulation results, using a two-dimensional device simulator, show that the deep p-well structure has better latch-up immunity compared to normal twin and triple well structures. In addition, it is more effective to minimize the distance to ground power compared with controlling a path to the $V_{DD}$ power.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.15 no.6
• /
• pp.827-831
• /
• 2012

Passengers and mounted equipments on a vehicle are exposed to the vibration when it is driven on the road. To minimize the vibration and improve the dynamic characteristics of a vehicle are important factors. Those are changed by modifying parameters of the vehicle. To save development cost and time, simulation methods using vibration model have been widely used before making the real vehicle. In this paper two aimed functions, displacement between wheels and the body and acceleration of the body, have been defined for the parameter sensitivity analysis of the large vehicle. Full Vehicle Model having 11 degrees of freedom applied to solve those issues.

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.5
• /
• pp.155-163
• /
• 2008

This study investigated biomechanical response through the 3-dimensional virtual skeletal model developed and validated. Ten male subjects in standing posture were exposed to whole body vibrations and measured acceleration on anatomical of interest (head, $7^{th}$ cervical, $10^{th}$ thoracic, $4^{th}$ lumbar, knee joint and bottom of the vibrator). Three dimensional virtual skeletal model and vibration machine were created by using BRG LifeMOD and MSC.ADAMS. The results of forward dynamic analysis were compared with results of experiment. The results showed that the accuracy of developed model was $73.2{\pm}19.2%$ for all conditions.