• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.3
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• pp.310-317
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• 2014

The Next-generation High-speed Rail Technology Development Project was started in 2007 by the Korean Government with the aim of developing the core technologies for a high-speed electric multiple unit (EMU) railway system. This is the first attempt to develop a high-speed EMU railway. High-speed EMU trains have superior acceleration and deceleration compared to push-pull high-speed railways such as KTX(Korean Train eXpress). A prototype train was developed and tested on a high-speed line starting in 2012. The new train must maintain running safety during the test. Generally, the international standard (UIC518) is adopted to evaluate the running safety of trains. This method suggests that the test zone must have over 25 sections, and the length of each section must be 500 m. However, it is difficult to implement these test conditions for a real high-speed line. In this study, we analyzed the running safety using several test section lengths (100 m to 500 m) and compared the results. The results of this study will be used to establish a running safety evaluation method for high-speed EMU railways.

• Wind and Structures
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• v.25 no.1
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• pp.63-77
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• 2017

When railway vehicles run by towers of long span bridges, the railway vehicles might experience a sudden load-off and load-on phenomenon in crosswind conditions. To ensure the running safety of the railway vehicles and the running comfort of the passengers, some studies were carried out to investigate the impacts of sudden changes of aerodynamic loads on moving railway vehicles. In the present study, the aerodynamic coefficients which were measured in wind tunnel tests using a moving train model are converted into the aerodynamic coefficients in the actual scale. The three-component aerodynamic loads are calculated based on the aerodynamic coefficients with consideration of the vehicle movement. A three-dimensional railway vehicle model is set up using the multibody dynamic theory, and the aerodynamic loads are treated as the inputs of excitation varied with time for kinetic simulations of the railway vehicle. Thus the dynamic responses of the railway vehicle passing by the bridge tower can be obtained from the kinetic simulations in the time domain. The effects of the mean wind speeds and the rail track positions on the running performance of the railway vehicle are discussed. The three-component aerodynamic loads on the railway vehicle are found to experience significant sudden changes when the vehicle passes by the bridge tower. Correspondingly, such sudden changes of aerodynamic loads have a large impact on the dynamic performance of the running railway vehicle. The dynamic responses of the railway vehicle have great fluctuations and significant sudden changes, which is adverse to the running safety and comfort of the railway vehicle passing by the bridge tower in crosswind conditions.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.909-914
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• 2009

A suspension is the most prior apparatus to decide vehicle's running safety and ride comfort, also the suspension stiffness is the most important parameter for the designing of the vehicle. Providing the strong stiffness with the primary suspension in order to improve the running safety with high speed, but it causes a problem with a curve running performance of a railway vehicle. Therefore, many studies deal with the optimal value of suspension stiffness. In this paper, we aim to optimize the suspension system to improve running safety by varying stiffness values of railway vehicle suspension. We have proceeded an analysis by design variables which are position, length, width, stiffness and damping coefficients of primary and secondary suspension to optimize the suspension characteristics. As a result of the optimization, we verified that the derailment coefficients of inside and outside of wheel are decreased in comparison with initial model.

• Journal of Nutrition and Health
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• v.33 no.8
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• pp.794-801
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• 2000

The purpose of this study is to determine the effects of the aerobic exercise type on macronutrient self-selection. Male Sprague-Dawley rats were placed on a macronutrient self-selection diet for 4 weeks. For this purpose, mixed feeds were prescribed for the rats while they were forced to swim and run for 4 weeks. Animals were either swimming exercise or treadmill running exercised at 20m/min(60min/day). Cumulative daily energy and macronutrient intake were determined during this period. The running exercise group gained weight much more than the control group, while the swimming exercise group lost weight less than the control group. Such findings suggests that the former group took more feed. On the other hand, the dietary efficiency of the control group was higher, which implies that no physical exercise would result in a higher dietary efficiency. And there was significant difference of total dietary and calorie intakes among the three groups, Although insignificant in statistical means, it was found that the running group took feed most, which is attributable to the homeostasis requiring the supplementation of the calorie lost by exercise. Also, the running exercise group took the protein and carbohydrate most. while the control group took fat most. The decrease of fat intake by the running exercise group suggests the possibility that the in-body enzymes should adapt themselves to the changing in-body condition caused by the endurance exercise. In contrast, it is conceived that the more intake of the carbohydrate may be attributable to the need of supplementing the nutrient lost by the endurance exercise. As discussed above, the endurance exercise group took carbohydrate and protein and less fat than control group. In particular, it was found that the amount of feed intakes was affected much by types, intensity and duration of the exercises. All in all, such findings would apply to human beings. Now can increase the intakes of carbohydrate and decrease the intake of fat through an effective running exercise program and thereby, change our dietary patterns to the benefit of our body and simultaneously, prevent and adult\\`s diseases by decreasing the in % body fat level.(Korean J Nutrition 33(8) : 794-801, 2000)

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.663-669
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• 2009

The purpose of this study was to investigate the functional role of foot effectiveness when humans execute running turn maneuvers. Foot rotation angle at the starting turn and body angle at the vertical axis were analyzed through three-dimensional image analysis and ground reaction force analysis. Then, we created a simple equation: foot effectiveness = total foot rotation angle/total body rotation angle at the vertical axis. This equation made it possible to explain the dynamics of angular running turns. We analyzed data from running turns(0, 30, and 60) at average initial running velocities of 4.5, as well as rotations around the vertical axis during the running turns. As a result, the stance time, foot placement, and left and right force increased.

• Korean Journal of Construction Engineering and Management
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• v.8 no.6
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• pp.139-149
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• 2007

The purpose of this study is to examine the problem of BTL(Build Transfer Lease) projects through comparative analysis on running costs, focusing on primary school, junior and senior high school education facilities, and then to provide useful information on the estimation of running costs by suggesting valid cost criteria. For this, eight schools from A and B consulting firms were sampled from capital region and other areas. Sampled schools were classified into four categories according to school grade, and running cost data are collected and analyzed from relative view points. The results of this study are as follows: 1) running costs which are analyzed by categories show some difference among sub-items, 2) major problems related to running cost prediction of BTL projects are revealed and improvement schemes are suggested for two groups (Owner and Project applicants).

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.29-35
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• 2018

Objective: The purpose of this study was to determine the asymmetry of vertical ground reaction force (GRF) components between dominant and non-dominant legs in rested and fatigued states in prolonged running. Method: Twenty healthy men, heel strikers, were included (age: $24.00{\pm}5.0years$; height: $176.1{\pm}6.0cm$; body mass: $69.0{\pm}6.0kg$) in this study. Subjects ran on an instrumented treadmill for 130 minutes. During treadmill running, GRF data (1,000 Hz) were collected for 20 strides at five minutes (rested) and 125 minutes (fatigued) running while they were unaware of collecting data. Asymmetry indexes (ASI) were calculated to quantify the asymmetry magnitude in rested and fatigued states. Paired t-test was used to verify the differences between dominant and non-dominant legs in rested and fatigued states. In addition, one-way repeated measure analysis of variance was applied for comparison of ASI of both states. The level of significance was set at p < .05. Results: Passive force peak magnitude, loading rate, and impulse affecting the development of running injury were found significantly greater in dominant leg than in non-dominant leg at rested state (p < .05). However, passive force peak time and active force peak magnitude were found significantly different between legs in fatigued state (p < .05). To determine changes in percentage of asymmetry between legs in both states, ASI was used. ASI for all variables increased in fatigued state; however, no significant differences were found between both states. Conclusion: This study found that fatigue did not affect differences in vertical GRF between dominant and non-dominant legs and asymmetry changes.

• Korean Journal of Applied Biomechanics
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• v.29 no.3
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• pp.173-183
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• 2019

Objective: The aim of this study was to investigate the correlation coefficients between anthropometric parameters of the foot and kinetic variables during running. Method: This study was conducted on 21 healthy young adults (age: $24.8{\pm}2.1yes$, height: $177.2{\pm}5.8cm$, body mass: $73.3{\pm}7.3kg$, foot length: $256.5{\pm}12.3mm$) with normal foot type and heel strike running. To measure the anthropometric parameters, radiographs were taken on the frontal and sagittal planes, and determined the length and width of each segment and the navicular height. Barefoot running was performed at a preferred velocity ($3.0{\pm}0.2m/s$) and a fixed velocity (4.0 m/s) on treadmill (Bertec, USA) in order to measure the kinetic variables. The vertical impact peak force, the vertical active peak force, the braking peak force, the propulsion peak force, the vertical force at mid-stance (vertical ground reaction when the foot is fully landed in mid-stance or at the point where the weight was uniformly distributed on the foot) and the impact loading rate were calculated. Pearson's correlation coefficient was used to investigate the relationship between anthropometric variables and kinetical variables. The significance level was set to ${\alpha}=.05$. Results: At the preferred velocity running, the runner with longer forefoot had lower active force (r=-.448, p=.041) than the runner with short forefoot. At the fixed velocity, as the navicular height increases, the vertical force at full landing moment increases (r= .671, p= .001) and as the rearfoot length increases, the impact loading rate decreases (r=- .469, p= .032). Conclusion: There was a statistically significant difference in the length of fore-foot and rearfoot, and navicular height. Therefore it was conclude that anthropometric properties need to be considered in the foot study. It was expected that the relationship between anthropometric parameters and kinetical variables of foot during running can be used as scientific criteria and data in various fields including performance, injury and equipment development.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.205-213
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• 2021

Objective: The aim of this study was to analyze body stability Joint coordination pattern though as bending stiffness of shoes during stance phase of running. Method: 47 male subjects (Age: 26.33 ± 2.11 years, Height: 177.32 ± 4.31 cm, Weight: 65.8 ± 3.87 kg) participated in this study. All subjects tested wearing the same type of running shoes by classifying bending stiffness (A shoes: 3.2~4.1 N, B shoes: 9.25~10.53 N, C shoes: 20.22~21.59 N). They ran 10 m at 3.3 m/s (SD ±3%) speed, and the speed was monitored by installing a speedometer at 3 m intervals between force plate, and the measured data were analyzed five times. During running, ankle joint, MTP joint, coupling angle, inclination angle (anterior-posterior, medial-lateral) was collected and analyzed. Vector coding methods were used to calculate vector angle of 2 joint couples during running: MTP-Ankle joint frontal plane. All analyses were performed with SPSS 21.0 and for repeated measured ANOVA and Post-hoc was Bonferroni. Results: Results indicated that there was an interaction between three shoes and phases for MTP (Metatarsalphalangeal) joint angle (p = .045), the phases in the three shoes showed difference with heel strike~impact peak (p1) (p = .000), impact peak~active peak (p2) (p = .002), from active peak to half the distance to take-off until take-off (p4) (p = .032) except for active peak~from active peak to half the distance to take-off (p3) (p = .155). ML IA (medial-lateral inclination angle) for C shoes was increased than other shoes. The coupling angle of ankle angle and MTP joint showed that there was significantly difference of p2 (p = .005), p4 (p = .045), and the characteristics of C shoes were that single-joint pattern (ankle-phase, MTP-phase) was shown in each phase. Conclusion: In conclusion, by wearing high bending stiffness shoes, their body instability was increased during running.

• Korean Journal of Exercise Nutrition
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• v.13 no.3
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• pp.203-209
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• 2009

Periventricular leukomalacia (PVL) is a common white matter lesion affecting the neonatal brains. PVL is closely associated with cerebral palsy (CP). It has been suggested that maternal or placental infection can induce damage to the neonatal brains. In the present study, we investigated the effects of treadmill running and swimming of rat pups on the GFAP and MBP expressions in the brains of rat pups with maternal lipopolysaccharide (LPS)-induced CP. The rats were divided into the six groups for experiment 1: the control group, the control with mild exercise group, the control with moderate exercise group, the LPS-treated group, the LPS-treated with mild exercise group, and the LPS-treated with moderate exercise group (n=6 in each group). The rats in the running groups were forced to run on a motorized treadmill for 30 min 5 times a week for 4 weeks. For experiment 2, the rats were divided into four groups: the control group, the LPS-treated group, the LPS-treated with swimming group, and the LPS-treated with treadmill running group (n = 5 in each group). The rats in the swimming group were made to swim for 30 min once a day for 5 times per week during 2 weeks. The rats in the treadmill running group were made to run for 30 min once a day for 5 times per week during 2 weeks. The present results showed that intracervical maternal LPS injection during pregnancy significantly increased GFAP expression in the striatum and significantly decreased MBP expression in the corpus callosum of rat pups. The present results also showed that treadmill running and swimming significantly suppressed GFAP expression and significantly enhanced MBP expression in the brains of rat pups with maternal LPS-induced CP. This effect of treadmill running was shown as equally both in the mild-intensity exercise and in the moderate-intensity exercise. The present study revealed that exercise, both the treadmill running and swimming, is effective for the treatment of astrogliosis and hypomyelination associated with CP. Here in this study, we showed that treadmill running and swimming are effective for alleviating the detrimental effects of CP.