• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.565-571
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• 2011

Because most fatigue cracks in wheel and rail take place by rolling contact of wheel and rail in railroad industry, it is critical to understand the rolling contact phenomena, especially for the three-dimensional situation. This paper presents an approach to steady-state rolling contact problem of three-dimensional contact bodies, with or without tangential force, based on the finite element method. The steady-state conditions are controlled by the applied relative slip and tangential force. The three-dimensional distribution of tangential traction and contact stresses on the contact surface are investigated. Results show that the distribution of tangential traction and contact stresses on the contact surface varies rapidly as a result of the variation of stick-slip region. The tangential traction is very close in form to Carter's distribution.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.392-396
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• 2004

The number of parameters and the number of samples are the key point of trans-log cost function which studied recently. Most of models show that the number of parameters is more than the number of samples. Therefore, these studies gave unreliability of the estimation results. First, we surveyed theoretical cases and researches for the formulation of cost function of railroad industry. Second, we will suggest trans-log cost function by analyzing cost data of KNR. And, the cumulative data will be needed for the confidence of estimation results.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1765-1769
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• 2004

The number of parameters and the number of samples are the key point of trans-log cost function which studied recently. Most of models show that the number of parameters is more than the number of samples. Therefore, these studies gave unreliability of the estimation results. First, we surveyed theoretical cases and researches for the formulation of cost function of railroad industry. Second, we will suggest trans-log cost function by analyzing cost data of KNR. And, the cumulative data will be needed for the confidence of estimation results.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.528-534
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• 2010

In the new growth theory, R&D stock is the third factor of production excluding a labor and capital. In this point, a R&D stock is located in a capital which is accumulated by money like existing capital and this is a knowledge capital. The effort for escalating this knowledge capital is R&D investment and R&D stock is an accumulation of this. A contribution degree of the economic growth and a return of R&D investments are analyzed by an estimation of relation R&D stock and a total factor of productivity. This study analyzed R&D stock of railroad R&D investments and compared R&D stock with a technical level. So, a technical level is proportionally escalated following escalation of R&D stock. and compared railroad industry weight on the GDP with a railroad R&D stock weight on whole industries R&D stock. According to a relatively small railroad R&D stock weight against the railroad industry weight, a continuous railroad R&D investment is needed.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.710-713
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• 2004

The domestic railroad industry 2004 April high-speed railroad commerce is the actual condition which is operated and the fact that in spite of railroad standard field many portion does not correspond in international standardize actuality. International standard correspondence propulsion direction and hereafter of railway rolling stock wheel standard it was presented from the research which it sees and the railway rolling stock wheel relation KS standard establishment by law direction it introduced.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.707-712
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• 2008

As RAMS becomes an international trend in the railroad industry, it is also generalized in the domestic railroad industry. This research is performed to present a criterion of the RAMS plan for the next generation high speed rolling stock. The criterion is developed based on IEC62278(EN50126), the international standard for railroad RAMS and CLC/TR 50126-2, 3, the guide to the application of IEC 62278. It is necessary for the export of the rolling stock. The criterion describes the RAMS targets and the contents to be included in the RAMS plan to meet the RAMS targets. Through developing the RAMS plan, we can identify RAMS activities and documents to be done in the total life cycle which includes design, manufacture and operation. It will help to accomplish synthetically the system targets of the next generation high speed rolling stock.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.791-794
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• 2009

Each nation of the world is intensively propelling the R&D investment to solve the financial crisis and worldwide economic recession occurred from last year. This means the world economic is under economic system based on the knowledge. So, The R&D is continuously propelled for possession of the technology through the R&D stock and which is core in the knowledge based economic system. In this world stream, our government is also increasing the R&D investment and checked the technology level through surveying the R&D stock and corn parison of each industry or world. The R&D investment of the railroad is continued but there is no data of the R&D stock. So, surveying the railroad R&D stock and comparing with korea industry is processed.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1618-1623
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• 2009

In this paper, we describe the design method of carbody structure with side-buffer. Recently railroad industry has a new interest with stability, fixed time, low environment pollution and mass transportation. Accidents have little on the railroad but railroad industry is trying to minimize carbody damage and passenger injury in case of accidents. So a side-buffer having anti-climber is applied to meet each special needs. Carbody with side-buffer is assembled with aluminum(6005A-T6) parts that are extruded. As the results of the study, it is showed that carbody with side-buffer has sufficient energy absorbtion about crashworthiness.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.2
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• pp.214-224
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• 2011

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1481-1498
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• 2007

As railroad industry face the new Renaissance era, effective and efficient maintenance methods for rolling stock operation are required with advanced railroad technology. All kinds of railroad systems such as high speed long distance train, metropolitan mass transit and light rail require systematic maintenance technology in order to maintain the safe railroad operation. Simulation models for detailed operations of the sample maintenance center are developed. In this study, standard maintenance procedures, layout, equipments and number of workers of Siheung Metropolitan Railroad Maintenance Rolling Stock Depot are considered. The proposed simulation models are developed using simulation package ARENA. Three simulation analysis using the developed simulation model are done. First, the bottleneck operation is identified. Second, the relationship between maintenance center size, number of workers and cycle time is analyzed. Lastly, the scheduling performances between PERT/CPM and Critical Chain Project Management(CCPM) are compared.