• LOGISTICS
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• s.10
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• pp.25-27
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• 2005

글로벌 경쟁체제의 도래와 정보화의 급진전 및 소비자의 권익신장 등 경제환경의 변화에 따라 고객서비스와 직결되는 물류의 중요성이 날로 강조되고 있다. 기업의 경쟁력 제고를 위한 물류의 아웃소싱 증가와 제3자물류산업의 활성화 및 공급사슬관리(SCM)의 보편화와 일관물류서비스에 대한 수요증가에 따라 물류센터의 기능 또한 종래의 보관 중심이 아닌 일관물류의 중심적 기능으로 발전하고 있으며, 일관물류서비스의 품질을 좌우하는 결정적 요소로 중시되고 있다. 이렇듯 물류센터의 기능이 중시되고 있음에도 현재 우리나라 물류센터들은 공급과잉과 정보부족 및 공급자의 영세성, 제도적 지원부족 등의 주요한 문제점들을 안고 있는 것으로 지적되고 있다. 이런 차에 지난 3월 31일 결성된 한국물류협회 물류센터분과위원횡 거는 관련 업계의 기대가 적지 않다. 이에 물류센터분과위원장으로 선임된 이강성 TL Korea 사장으로부터 우리나라 물류센터의 실태와 분과위원회의 지향점 등을 들어본다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1110-1115
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• 2002

The purpose of this study is to analyze the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type passenger vehicle. According to the results of simulation and the small scale vehicle test. Optimal condition was obtained for the stiffness ratio of the primary spring and secondary spring of the suspension system. When the stiffness ratio was Increased, the vortical vibration was increased on the car body for empty and weight car. The result of this study are stable to use of the optimum parameter of the ride duality of KT-23 type vehicle. Also, it is usefull to development of full scale vehicle dynamomer

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.994-999
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• 2003

A modeling method for the modal analysis of a rotating cross-ply composite beam based on Timoshenko beam theory is presented. To analyze the composite beam exactly, the effects of shear deformation and rotary inertia are included. Linear differential equations of motion are derived using the assumed mode method. For the modeling, hybrid deformation variables are employed and approximated to derive the equations of motion. The effects of the dimensionless angular velocity and the slenderness ratio parameter on the variations of modal characteristics are investigated

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.159-165
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• 1998

중트럭 통행으로 인한 철근콘크리트 교량바닥판의 열화는 교량구조물을 유지보수하는데 있어 심각한 문제 중 하나이며, 프리캐스트 바닥판을 이용한 교량바닥판의 시공 및 교체 방법이 실용적이며 효과적인 방법으로 인식되고 있다. 본 연구에서는 횡방향 ddusruf부에 종방향 프리스트레싱을 도입한 프리캐스트 바닥판의 모델을 제작하여 바닥판간 횡방향 연결부의 강성 평가 및 연결부의 피로 거동을 파악하기 위해서 피로실험을 수행하여 피로하중하에서의 휨강성의 변화, 균열발생 및 파괴하중 등을 측정하였다. 실험결과를 통해서 피로하중하에서 프리스트레스 프리캐스트 부재의 프리스트레스 효과를 평가하였으며, 현장타설에 의해서 시공되는 일반 RC 부재에 비해서 우수한 구조적 거동을 보여주는 적정량의 종방향 프리스트레스 크기를 결정하였다.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.786-791
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• 2004

This study proposed the analysis of mass position detection and modified stiffness due to the change of the mass and stiffness of structure by using the original and modified dynamic characteristics. The method is applied to examples of a cantilever and 3 degree of freedom by modifying the mass. The predicted detection of mass positions and magnitudes are in good agreement with these from the structural reanalysis using the modified mass.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.834-839
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• 2004

In this paper, modeling methods for the structural dynamic analysis employing single reference frame are presented and their modal and transient analysis results are compared. The geometric stiffening effects often occur when structures undergo large overall motion. These effects were considered in several structural previous modeling methods but the role of reference frame has never been scrutinized. In this study, modeling methods employing single reference frame are presented, and their numerical results are compared. The results show that discrepancy between the two modeling methods increases as the eccentricity of the structural system and the magnitude of the large overall motion increase.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.4
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• pp.7-12
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• 2005

This study predicts the modified eigenvectors and eigenvalues of the damped structure due to the change in the mass, damping and stiffness of structure by calculation of the sensitivity coefficient using the original dynamic characteristic. The method is applied to examples of the damped 3 degree of freedom system by modifing the mass, damping and stiffness. The predicted dynamic characteristics are in good agreement with these from the structural reanalysis using the modified mass, damping and stiffness.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.598-605
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• 2000

The design of a current collection system of high speed train requires the fundamental understandings fer the dynamic characteristics of a catenary system and pantograph. The stiffness of the catenary system of high speed train has the varying characteristics for the change of the contact point with a pantograph, since the supporting pole and hanger make the different boundary conditions for the updown stiffness of a trolley wire. The variation of stiffness results in Mathiue equation, which characterizes the stability of the system. However, the two terms variation of the stiffness due to span length and hanger distance cannot be solved analytically. In this paper, the stiffness variations are calculated, and the physical reasoning of linear model and one term Mathieu equation are reviewed. And the numerical analysis for the two term variation of the stiffness is done for the several design parameters of the pantograph.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.265-267
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• 2013

Tire labeling is an important issue to reduce $CO_2$ and to secure the safety of tire/vehicle on wet road. A basic study on the effects of tire basic stiffness design on tire labeling performance has been done through experimental test. The pass-by noise is affected by tire structural design. The tire with lower side part stiffness and lower tread part stiffness has the lowest PBN level and the best wet grip. And the tire with higher tread part stiffness and higher side part stiffness has the better RR performance. Also it is observed that the trade-off between RR and wet grip exists for various tire stiffness design.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1622-1627
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• 2008

A suspension is a core part, determining running stability and riding quality of vehicles and its stiffness is essential parameters in the process of vehicle designing. Suspension stiffness shall be adjusted to meet requirements of running stability and curve running performance, as adding stiffness to primary suspension for running stability in high-speed running results running performance degradation in curved track. The purpose of the report lies in utilization of usable data for optimization of suspension via analyzing running performance through changing stiffness of railway vehicle suspension.