• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1223-1228
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• 2001

We have been developing the pantograph for Korean High Speed Train for the last five years. To fulfil the following requirements at designed speed of 350km/h ： 1) contact loss less than 1 ％, 2) aerodynamic noise less than 91dB, 3) average uplift force less than 200N, the pantograph has been modified two times since the first prototype pantograph was manufactured, By means of the following up characteristic test, low speed wind tunnel test, and high speed wind tunnel test for the prototype pantographs, we found that the aerodynamic uplift force did not exceed l60N at speed up to 350km/h and the aerodynamic noise was less than 88dB, that the following up characteristics of the prototype pantograph was excellent.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1053-1062
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• 1993

The effect of loading speed on soil failure was studied by using a high speed triaxial compression test. Tests were conducted at 0.35-6.2m/s loading speed to compress soil specimens of sandy loam at different moisture contents. The axial stress at fracture increased with increase in loading speed up to certain critical speeds, however they decreased as the speed up to certain critical speeds, however they decreased as the speed increased further. Experiments were also conducted in the field of sandy loam soil with the vibrating tillage tool. Tests were done at 0.33-0.85m/s tractor speed oscillating frequency 13.7hz and oscillating amplitude 59mm. The maximum oscillating velocity of tillage tool was 2.5m/s. It was observed that for the oscillating operation, initially draft slightly increased with increase in forward speed and then it decreased .For the non-oscillating operation, draft increased continuously with increase in forward speed. Approach of studying soil failure in the laboratory test can be related to the field experiments.

• International Journal of Railway
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• v.6 no.2
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• pp.78-84
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• 2013

This paper is about the first experiment in Korea that was conducted on speeding increase up with rail speeds at 430km/h at high speed railway of designed 350km/h. and analysis data collected on vibration accelerations of roadbed. There are barely references on roadbed behavior measurement with rail speeds more than 350 km/h in Korea as it has never been conducted the experiment on it. So the experiments were confirmed the reliability through crosschecking the figures/values from respective sensors and measuring devices after measuring EMS and ICP types. Based on the study, values of vibration acceleration were less than 12% compared with the ones that conducted while speeding up of HEMU-430X. Also, figures of HSB for concrete bed tracks were 52% against the standard. According to the results, all the performance evaluation of vibration acceleration for roadbeds in transition zones is under the standard.

• Physical Therapy Korea
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• v.11 no.1
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• pp.1-17
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• 2004

The purposes of this study were to find correlations among Fugl-Meyer Assessment scale, gait speed, and Timed Up & Go test (TUG) and to predict gait ability from subscales of Fugl-Meyer Assessment scale. The study population consisted of 30 stroke patients referred to the Department of Rehabilitation Medicine in the Bundang Jaesang General Hospital. All subjects were ambulatory with or without an assistive device. All participants were assessed on Fugl-Meyer Assessment scale and gait speed (m/s), TUG (s). The data were analyzed using independent t-test, Pearson product moment correlation analysis and stepwise multiple regression. The results revealed that all items of Fugl-Meyer Assessment scale, except passive joint range of motion were significantly correlated with gait speed and TUG. In particular, sensation score, lower extremity motor and coordination score have a significant correlation with gait speed and TUG (p<.05). The sensation score and lower extremity motor score were important factors in comfortable gait and maximal gait speed. Their power of explanation regarding comfortable gait and maximal gait speed were 63.0% and 65.0%, respectively. The sensation score and lower extremity coordination score were important factors in TUG. Their power of explanation regarding TUG was 55.0%. These results showed that Fugl-Meyer Assessment scale is significantly correlated with gait speed and TUG. Therefore Fugl-Meyer Assessment scale is an appropriate assessment tool to predict gait ability of patients with stroke. Further study about gait speed and TUG by change of Fugl-Meyer Assessment score is needed using a longitudinal study design.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.212-216
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• 2001

Recently, it has been trending toward speed-up not only in the passenger car but in the freight cu. In this study, we thus performed stress analysis for the carbody for high speed container freight car in use and field test of the freight car in Gyungbu-line so that we may utilize the results as a design guide for speed-up hereafter- Five vertical loading conditions due to dynamic effect and the weight of the carbody and the container applied to locking devices of the carbody and its results are compared with that of a test, As a result, we found that there is need to complement the strength of the carbody in some measure when speed up the present freight car.

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

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.6
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• pp.284-292
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• 2005

Because all of the short-circuit testing laboratories have the limitation of test facilities, the synthetic making test methods have been used to estimate the short-circuit making performance of the ultra high-voltage circuit breaker as the alternative to direct test methods. So, KERI(Korea Eelctrotechnology Research institute) has completed the construction of the synthetic making test facilities using the low capacity step-up transformer method which fulfill the requirements specified in newly revised IEC 62271-100 Edition 1.1(2003) and have the testing capability up to 550kV, 63kA full-pole circuit breaker. The test facilities using the low capacity step-up transformer method presented in this paper are made up of the unit equipments such as HCS(High-speed Closing Switch), ITMC(Initial Transient Making Current) circuit and UP TR(low capacity step-up transformer) and have the operating range of 17.6$^{\circ}$ $\~$ 145.1$^{\circ}$ for testing the circuit breaker rated on up to 50kA and 43.1$^{\circ}$ $\~$ 119.6$^{\circ}$ for more than 50kA.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.145-151
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• 2022

Purpose : Stroke patients exhibit abnormal walking patterns such as slow walking speed and asymmetrical walking values. The recovery of symmetrical walking in the stance phase using a treadmill means improvements in walking speed and asymmetrical walking. The purpose of this research was to investigate the effect of unilateral step treadmill training (USTT) on gait speed and the recovery of symmetrical walking in chronic stroke patients. Methods : Fifteen patients (11 men and 4 women) with chronic stroke participated in this study. The 10-meter walk test (10MWT) and GAITRite system were used to determine the intervention-related changes in gait speed and symmetrical walking values such as non-paretic step length (NSL), non-paretic step time (NST), paretic single-support time (PSST), step length asymmetry (SLA), and step time asymmetry (STA) after USTT. All participants completed USTT and underwent measurements at 3 different times: at pretest, posttest, and the follow-up test. Repeated-measures analysis of variance was used to compare walking speed and asymmetrical walking values. The statistical significance level was set at p<.05. Results : Walking speed by 10MWT (p<.05) showed significant improvements after USTT as follows: at pretest and posttest (p<.05), posttest and follow-up test (p<.05), and pretest and follow-up test (p<.05). Recovery of symmetrical walking patterns such as NSL (p<.05), NST (p<.05), and SLA (p<.05) were observed after USTT. However, no significant improvements were found in PSST (p>.05) and STA (p>.05) in symmetrical gait. Conclusion : This study suggests that USTT may have a positive effect on walking speed and symmetrical walking patterns in chronic stroke patients. Thus, this study contributes to the existing knowledge about the usefulness of USTT for the effective management of patients with chronic stroke. Further studies are needed to generalize these findings.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.334-338
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• 2004

KTX has started commercial service from Seoul to Busan and Mokpo since April 1, 2004. The service line is composed of new-high speed line and conventional line. Before KTX is runs, the maximum operational speed on conventional line was 140km/h. In order to reduce the traveling time, operation speed of KTX must be increased on the conventional line. So, we performed test running with prototype HSR-350x and verification of safety was made in $10\%$ speed-up. Korean High Speed Train HSR-350x) was developed by G7 - R&D project. In this study, in safety aspect, several technical reviews are introduced and the possibility for reduction of traveling time is investigated on the conventional line by using HSR-350x.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.401-409
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• 2015

Defects generated in a railroad track that guides the railroad vehicle have the characteristic of growing fast; as such, the detection technology for railroad track defects is very important because defects can eventually cause mass disasters like derailments. In this study, a speed-up test facility was fabricated to investigate the feasibility of using magnetic flux leakage (MFL) technology for defect detection in a railroad track under speed-up condition; a test was conducted using a railroad track specimen with defects. For this purpose, an MFL sensor head dedicated to the configuration of the railroad was designed and test specimens with artificial defects on their surfaces were manufactured. Using the test facility, a speed-up test ranging from 4km/h to 12km/h was performed and defects including locations were successfully detected from MFL signals induced by defects with enhanced visibility by differentiating raw MFL signals. In the future, it should be possible to apply this system to a high-speed railroad inspection car by improving the lift-off stability that is necessary for speed-up of the developed MFL sensor system.