• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.161-168
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• 2005

Torsional behavior of eccentric structure under seismic loading may cause the stress and/or deformation concentration. Hence it is hard to estimate the seismic behavior of the structure with plan irregularity. This study suggests the method to setup the seismic fragility curve of the torsionally irregular structures. The suggested fragility curve may be acquired from the fragility surface defined on the D-R plan according to the estimated torsional behavior. The torsional behavior is predicted considering the inelastic region by adapting the inelastic stiffness of each wall. Finally the system displacement is converted to the spectral acceleration and the fragility curve for the seismic excitation level is presented. In addition, the fragility curve considering the excitation direction is proposed.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.236-243
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• 2005

Nonlinear static analysis is used to quantify the resistance of the structure to lateral deformation and to gauge the mode of deformation and intensity of local demands. A simple method for the nonlinear static analysis of complex building structures subjected to monotonically increasing horizontal loading(pushover analysis) is presented. The method is designed to be a part of new methodologies for the seismic design and evaluation of structures. A variety of existing pushover analysis procedures are currently being consolidated under programs such as ATC 40 and FEMA 273. And various techniques have been recommended, including the use of constant lateral force profiles and the use of adaptive and multimodal approaches. In this paper a modal pushover analysis using design response spectra of UBC 97 is proposed. Proposed method is compared against the method in FEMA 273 and ATC 40, and results of time history analysis.

• 약학회지
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• 제48권2호
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• pp.130-134
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• 2004

Phellinus linteus (Hymenocaetaceae) has been used for the treatment of gastric cancer, noninsulin dependant diabetes, diarrhea, and menstrual irregularity. The antioxidative effect of cultivated fruit body of Phellinus linteus on low density lipoprotein oxidation was investigated. The MeOH and water extracts were examined by TEARS assay on human plasma LDL in vitro system. The MeOH ex. showed antioxidative activity, and then was fractionated into Precipitates, Water Insoluble fr., Water fro and ether fro The results showed that the lipophilic fractions, Water Insoluble fr. and Ether fr. of cu 1-tivated fruit body of Phellinus linteus, inhibited the oxidative modification of LDL.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.473-478
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• 2005

Active suspension system improves ride quality with optimized suspension force, generated by electric, hydrolic or pneumatic power and controlled by micro-processor under various operation condition of train, while Semi-Active susepsion system provides optimized and controlled characteristics of suspensions such as damping coefficient without external energy. The benefits fo Semi-Active suspension are no required power source and to be made compact with lower cost. Train with narrow gauge could be more unstable than one for normal or wide gauge, and it could be more vibrated than others one by external force such as aerodynamic force and track irregularity. So, the reduced ride quality could be improved with appling with Semi-active suspension system. In this report, the Semi-Active suspension system for narrow gauge train shall be proposed and to prepare the Roller Rig test of this train, integration of system, development of control algorithm and confirmation of its performance with simulation tool would be taken.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.182-187
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• 2007

The accuracy of the results of the rail vehicle dynamic model is dependent on the realism of the track input to the model. An important part of the track input is the irregularities that exist on actual track. This study presents a modeling method for creating track data with the irregularities for use as the input to VAMPIRE, a rail vehicle dynamic analysis program. The characteristics of the measured track data using the mid chord system has been studied and examined the method to create track data with the measured data to apply in the vehicle dynamic analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.303-310
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• 2007

In this paper, the correlation between the vibration characteristics of the track components and the parameters affecting the vibration is analysed. To do it, the accelerations of each track component such as rails, sleepers and ballast are measured in Kyong-Bu high-speed railway lines. The RMS values of the measured data are calculated and the corrugation, the track irregularity and the pad stiffness are considered as the parameters in the viewpoint of track. By using the linear regression, the correlation coefficient is calculated to analyse the relationship. The parameter whose correlation coefficient is more than 0.7 is considered as the major one. Also, the 1/3 Octave analysis is calculated to analyse the dominant frequency band of the vibrations of the track components.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.358-368
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• 2007

At this current, KORAIL track maintenance system has been worked with the method of corrective maintenance which is repaired some location exceeded the track management criteria as a result of track measurement. It brings about a lot of additional expenses that the corrective maintenance might be a way of missing an appropriate maintenance time, after occurring some trouble on the track due to track maintenance characteristic. We sincerely need a track maintenance system including the concept of preventive maintenance that track is corrected with predicting the trend of track irregularity. I would like to present a development direction for Korea track maintenance system having a good application in our track with analyzing TRAMS21 and RAMSYS as overseas railway company has operated a track maintenance system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.30-35
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• 2010

The railway vehicle is a multi-body system running on the track which consists of carbody, bogie and wheelset, each of components is connected with rigid mass, spring and damper. each of components has translation motions of longitudinal (X axis), lateral(Y axis) and vertical(Z axis) direction, and rotation motions of X, Y, Z axis which are named Rolling, Pitching and Yawing. The vibration mode of railway vehicle is difficult to find the characteristics of motion during the operation on the track because these happen to independence or duplication motion caused by vehicle, wheel/rail and track irregularity etc. This paper presents the result of ramp test to show the bounce, roll, pitch and yaw mode frequency of the railway vehicle.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.249-255
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• 2010

Ballasted track is under the circumstance of repetition of deterioration and recovery. Track deterioration is presented as track irregularity or settlement, and dynamic force subjected to track is one of major cause of the deterioration. The dynamic force is determined from the dynamic interaction between track and vehicle. Rail-pad stiffness is one of the factor affects track dynamic property. In this study, the relationship between rail-pad stiffness and track settlement was investigated. Dynamic forces according to various rail-pad stiffness was obtained from the dynamic vehicle-track interaction analysis using DARTS-NL. Track settlement was calculated by substitution the dynamic forces into various formulas for track settlement. From the result of analysis, it was known that the track settlement is increased about 6% when the rail-pad stiffness rise about twice. And this result leads that there is only a little relationship between rail-pad stiffness and track settlement.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.272-277
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• 2007

Generally railway vehicle runs on the rail with endless interaction between wheel and rail. Irregularity of rail causes the periodic motion of the vehicle. In association with this motion, the design of vehicle would be carried out in order to avoid the resonance between car-body and bogie. It may be seen that the first vertical bending mode of car-body contributes considerably to the vertical ride comfort level. In this paper to know the effect of the car-body first vertical bending mode on vertical ride comfort, the mode has been considered with dynamic model. I-DEAS program was used to get the car-body first vertical bending mode and VAMPIRE program was used to analyze ride comfort index(Wz) with FE interface file.