• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1088-1091
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• 2009

In a tilting train, aluminium honeycomb composite panel is used for the high speed and light weight. Side wall of the tilting train includes the composite panel of carbon fiber, aluminium honeycomb and epoxy fiber as a main structure. In this study, we measure the transmission loss (TL) of the honeycomb composite panel and analyse the sound insulation performance by using the orthotropic plate model. We investigate experimentally how the air gap, plywood and glass wool improve the sound insulation performance of the composite panel. The purpose of the study is to provide practical information for the improvement of TL of the honeycomb composite panel used for the tilting train.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.427-433
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• 2002

An inverter-driven induction motor is usually adapted to the traction motor for a high speed drive system requiring safety, reliability, performance, compact size owing to the space and weight alloted for attaching to train, etc. and AC Traction motor for G7 train will be operated in the worst condition such as mechanical vibration, limited mounting space, severe thermal stress, inverter with non-sinusoidal voltage waveform, dust and so on. therefore, design procedure must be carefully carried out wi th considering the motor size, vibration and thermal expansion of rotor bars, insulation system, reliability of frame, as well as output characteristics. In this paper, we will inform the characteristics and design of the traction motor for G7 train and also analyze the test result of it.

• Journal of Power Electronics
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• v.12 no.6
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• pp.992-1002
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• 2012

In this paper, the series chopper based power train for electric vehicle is proposed for aiming the increase of one battery charge driving distance. Both the motor test bench based experiments and the chassis dynamo based experiments are tested and then analyzed for EV driving performance that the proposed power train with SAZZ chopper and Quasi-PAM control scheme is compared with or without the series chopper. It is confirmed through two kinds of experimental analyses that the series chopper power train for EV can be useful to extend the driving distance if the high efficiency and the low weight of chopper are satisfied.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.479-486
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• 1999

The noises generated from the air-conditioning duct are known to strongly affect the indoor-noises of high speed trains. The acoustic characteristics of an air-conditioning duct should depend on the geometry and shape of the duct. The structural material for Korean high speed train is supposed to be changed from Steel, which was used for TGV, to Aluminum in order to reduce the total train weight. Accordingly, the shape and layout of the air-conditioning duct of Korean high speed train will be different from that of TGV. Thus, this paper introduces a analytical method to predict the noise attenuation through the air-conditioning duct, based on the ISO 7235. In this method, the whole duct is divided into several pieces and the noise attenuations predicted for each duct piece are integrated to get the noise attenuation for the whole duct system. The validity of the method introduced herein is discussed through some numerical tests.

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.142-148
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• 2022

In this paper, the weight reduction design of the yaw gearbox for wind turbine was performed through the finite element analysis method, and the stability was checked by performing the critical speed analysis. The weight reduction product can improve engine efficiency, save parts materials, and earn economic benefits. The yaw gearbox is lightweighted with the goal of achieving a safety rate of 1.3 or higher for wind turbine as indicated by IEC61400-1. In order to reduce the weight of the carrier, a topology optimization method was performed. The safety factor was verified by performing finite element analysis on the carrier. In addition, the housing and carrier were modeled using the finite element method, and the gear train was modeled using MASTA. For the yaw gearbox, the housing and carrier FE model and the gear train model were connected by the partial structural synthesis method to perform the rotational vibration analysis. Vibration excitation sources are mass unbalance and gear mesh frrequemcy, and as a result of the critical speed analysis, it was found that there was no resonance within the operating speed range.

• Journal of Korean Physical Therapy Science
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• v.9 no.1
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• pp.53-59
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• 2002

This study is research for effect of the involved lower limb weight bearing training on symmetrical weight supporting rate improvement by practicing involved lower limb weight bearing training of three weeks period to improve standing equilibrium problem with asymmetric weight supporting rate of hemiplegia. In result of the study, it has shown that P-value incase of involved supporting rate is lower than level of significance $\alpha$<.05 and mean improvement rate of experienced group is higher in comparison with controlled group and experienced group. In changing quantity of involved maximum supporting rate, P-value is .26 and higher than level of significance $\alpha$<.05, and so it did not show significant difference statistically. But in case of experienced group between pre and post-test, involved side supporting rate and involved side maximum supporting rate showed significant improvement in all. In comparison of relative characteristic training effect difference, it was shown that train-learning effect on case of 40-60 years old, hemorrhagic patient and standard body bun of patient is valuable, which showed significant improvement in case of paralytic side and disease period, it did not show significant difference on excercise learning effect in two above cases. In the above result, we can say that continuous weight bearing training on the involved lower limb for three weeks period help improve the involved side supporting rate of hemiplegia. Accordingly, the weight bearing training on the involved lower limb is training method that patient can easily train with simple guidance of therapists, without being special expensive equipment. Furthermore it can be helpful to establish home therapeutic plan for hemiplegia through education of a patron.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.411-416
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• 2002

The strength evaluation of a wheel is becoming very important due to the high speed of railway system and the reduction of wheel weight. Therefore, in this study, the influence of thermal stress at tread breaking in Korean High Speed Train wheel was investigated using FEM. During FEM analysis, the mechanical load or wheel-rail contract load and braking load were considered. When 300% of the block force was applied, the maximum von Mises stress of 61.0 ㎫ was found at the outside plate around 400mm far away from the wheel center.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.302-307
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• 2010

Development of light-weight high speed train (HST) based on distributed motor control with the top speed of 350 km/hr has engendered a need for abatement of the interior noise of the train cabin. The development of noise abatement measures is crucial at the design stage of the train car since the noise transmission characteristics of the car structure directly influences the cabin interior noise. Since the transmission loss measurement using the entire car structure is often not feasible, especially at the initial stages of the train development, investigation of transmission characteristics using small-scale reverberation chamber can furnish useful alternative source of predicting the noise level. In the present study, white noise is generated at source and transmission loss estimated by performing measurement of a specimen in a scaled reverberation chamber. Comparison of measured values with the previously derived numerical values show good agreement in the overall trend but appreciable quantitative differences still remain.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.435-442
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• 2004

Tilting train allow the train to pass curve at higher speed without affecting passenger comfort. As the tilting trains run curve track about 30$\%$ higher than non-tilting trains, the centrifugal force and dynamic force will be higher. Therefore it is very important for tilting train to ensure safety against derailment, and to reduce the lateral track forces by applying light-weight design, optimized suspension design and steering mechanism. The 180 km/h Korean Tilting Train(TTX) which is now developing as a part of the Korean National R & D project, was designed and analytically verified to meet these special requirements. This paper describes the analytic study to verify the safety against derailment, especially on the wheel unloading in case of tilting actuation. The severest curve geometry and curving speed was assumed, the tilting control pattern was also assumed as trapezoidal force function applied to tilting bolster and bogie frame. For the comparison, the operation with the speed of tilting train without tilting actuation was numerically simulated and the operation with the balanced speed without tilting actuation was also numerically simulated. Through the numerical simulation of various operating case, we found that derailment quotients, wheel unloading and Q/P was not affected by tilting actuation and that the bogie of TTX was nicely designed to satisfy the safety against the derailment.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.178-182
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• 2000

The purpose of this study is to investigate the train seat dimensions suitable for keeping comfortable postures. We designed a special experimental seat of which the lengths and angles are adjustable separately. Seat dimensions keeping subjects comfortable were measured for the restricted posture and the extended posture. The significant differences of dimensions fur two postures were analyzed, and the differences were found on backrest-seatpan angles, length of backrest and so on. The dimension differences fur the levels of height and weight were also found out. Some dimensions were correlated with subjects' height and weight..