• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1360-1365
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• 2010

The TBO of main unit of propulsion control devices on high-speed railway vehicles proposed by the makers is appropriated 10 years cycle, but the maintenance of internal device are proceeding before coming to the particular period of time. In the Future, increasing of the failure probability occurred by increasing train service and obtaining spare parts are predicted that it would be difficult. the propulsion control devices develop is needed in other to the ease maintenance, cost savings and ensuring related domestic technologies when considering operating on long term of high-speed railway vehicles. In this paper, we proposed development a way that current-controlled type propulsion control devices using the newest power semiconductors which is easy to supply and demand through identifying performance and characteristics of existing current-controlled type propulsion control devices of high-speed railway vehicles.

• 한국정밀공학회지
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• 제31권9호
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• pp.773-776
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• 2014

KTX (Korea Train eXpress) is the first high-speed train operated in Korea and its highest speed reaches 300 km/h. Korean high-speed trains are mostly operated on the railroads exclusively designed for high-speed trains, but the sections of Seoul~Gwangmyeong, nearby of Daejeon station and Dongdaegu are operated on the existing tracks having the speed less than 150 km/h. With this paper, we'd like to analyze the lateral force that occurs between the wheels and the rail when high-speed trains were operated on the existing track section to suggest an appropriate driving speed for high-speed trains. As the rigid wheel base of the high-speed train is 3m which is about 50% longer than normal vehicles, it works as an advantage for high-speed driving. However, as the lateral force becomes higher than normal vehicles when driving on curves, plans to reduce wear-outs on the wheels are required.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1720-1723
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• 2003

Recently, as the road capacity reaches a limit and environmental problems becomes serious, there exists a gradually increased need for railway vehicles that are environment-friendly, punctual, reliable and safe. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. Korean High Speed Train has been developed for last 6 years to satisfy the need. Authors developed a measurement system for on-line test and evaluation of performances of Korean High-Speed Train. The measurement system is composed of software part and hardware part. Perfect interface between multi-users is possible. A new method to measure temperature was applied to the measurement system. By using the system, measurement and evaluation of the mechanical characteristics of motors and main transformers in Korean High Speed Train was conducted during test running. The measured results for the temperature characteristics of electric devices verify that the measurement system is accurate and reliable.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권1호
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• pp.135-158
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• 2018

High-Speed vehicles can be considered as multiple mobile nodes that move together in a large-scale mobile network. High-speed makes the time allowed for a mobile node to complete a handover procedure shorter and more frequently. Hence, several protocols are used to manage the mobility of mobile nodes such as Network Mobility (NEMO). However, there are still some problems such as high handover latency and packet loss. So efficient handover management is needed to meet Quality of Service (QoS) requirements for real-time applications. This paper utilizes the cross-layer seamless handover technique for network mobility presented in cellular networks. It extends this technique to propose QoS-aware NEMO protocol which considers QoS requirements for real-time applications. A novel analytical framework is developed to compare the performance of the proposed protocol with basic NEMO using cost functions for realistic city mobility model. The numerical results show that QoS-aware NEMO protocol improves the performance in terms of handover latency, packet delivery cost, location update cost, and total cost.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.328-335
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• 2005

For high speed railway vehicles, we consider a vibration of flexible track/wheel system. It is very important to deal with the complex phenomena of high-speed vehicles that can be occurred in the vertical vibration of the system. From a viewpoint of multibody dynamics, this kind of problem needs accurate analysis because the system includes mutual dynamic behaviors of rigid body and flexible body. The simulation technique for the complex problems is also discussed. We consider the high-speed translation, rail elasticity, elastic supports under the rail and contact rigidity. Eigen value analysis is also completed to verify the mechanism of the coupled vertical vibration of the system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.378-382
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• 2005

The opening of high speed railway upgraded our land transportation speed limit, causing lots of changes including living and culture and also paving the way for stepping up the railway technology. However, it is also true that we had a limit to adopt the existing railway system structured for 150km/h to the new structure requiring a higher speed of approximate 300km/h due to technological, based on the time and experience. More importantly, heading toward a step of operating such a high speed railway system, it has been practically and quickly proposed that the railway needs high speed railway engineering, maintenance technology of parts of the vehicles to have a stable maintenance foundation and localization of major parts. Therefore, this study was intended to research the actual displacement characteristics in runningg on an actual track for the purpose of developing the protective and maintenance technology of springs and dampers, which are core parts among suspension elements of a high speed railway vehicle. For this, it was researched the actual vehicle test and its interpretation centered on primary spring, which is used for the suspension system of a bogie, body-body dampers and body-bogie yaw damper. Also, to analyze the displacement characteristics of suspension system in the actual conditions of high speed railway vehicles, a vehicle‘s dynamic characteristics was analyzed and interpreted. At the same time, a tester for measuring the actual displacement of such suspension elements was designed and attached to actual vehicles, to measure the displacements that occur in running it on the Seoul-Busan line, one of major lines serviced by KTX. The displacement data gained from the test with actual vehicles was analyzed for its displacement distribution depending on the service sections and frequency, with which the valuable data necessary for any potential breakdown or maintenance in the future could be obtained.

• 항공우주시스템공학회지
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• 제7권3호
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• pp.7-14
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• 2013

Hypersonic vehicles over Mach 5 need active cooling or thermal management systems to resolve excessive heating problems on their fuselage and engines. Endothermic fuels are widely used these days not only for the energy source but also for a heat sink. Therefore, fuel supply systems of hypersonic vehicles should be mainly composed of adiabatic fuel storage tank, cooling systems for the airframe and engine/nozzle, and fuel supply/injection systems in high pressure, high temperature, and high fuel flow rate conditions. This paper describes a conceptual design process of a hypersonic fuel supply system in order for designing a layout of the system, and identifying components and their specification requirements.

• 제어로봇시스템학회논문지
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• 제17권4호
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• pp.313-320
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• 2011

Multi-axle driving vehicles that are used in special environments require high driving performance, steering performance, and stability. Among these vehicles, 6WS/6WD vehicles with middle wheels have structural safety by distributing the load and reducing the pitch angle during rapid acceleration and braking. 6WS/6WD vehicles are favored for military use in off road operations because of their high maneuverability and mobility on extreme terrains and obstacles. 6WD vehicles that using in-wheel motor can generate the independent wheel torque without other mechanical parts. Conventional vehicles, however, cannot generate an opposite driving force at each side wheel. Using an independent steering and driving system, six-wheel vehicles can show better performance than conventional vehicles. Using of independent steering and driving system, the 6 wheel vehicle can improve a performance better than conventional vehicle. This vehicle enhances the maneuverability under low speed and the stability at high speed. This paper describes an independent 6WS/6WD vehicle, consists of three parts; Vehicle Model, Control Algorithm for 6WS/6WD and Simulation. First, vehicle model is application of TruckSim software for 6WS and 6WD. Second, control algorithm describes the optimum tire force distribution method in view of energy saving. Last is simulation and verification.

• 대한기계학회논문집B
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• 제33권5호
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• pp.358-364
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• 2009

This paper is to investigate the influence of driving patterns of slow and high speed vehicles on the performance of continuously regenerating diesel particulate filter(DPF) system matched with operating conditions in field application. The DPF performance test for field application was carried out for two identical DPFs installed to slow and high speed vehicles. A slow speed vehicle was selected among local buses which have driving patterns to repeat running and stop frequently, while a high speed vehicle was prepared to have long route of high speed over 60km/h like inter-city buses. In this test, the regeneration performance on the DPF of slow speed vehicle deteriorated because of high soot load index(SLI) in spite of same balance point temperature(BPT) distribution for high speed vehicle. The DPF of slow speed vehicle melted in the end because the rapid increase of back pressure caused high temperature over $1200^{\circ}C$ in the ceramic wall of DPF. The PM components like ash collected to the filter in the DPF were analyzed in order to investigate the cause of the defect and provide an operation performance of DPF system. In the result of the analysis, high levels of lubrication oil ash(Ca, Mg, P, Zn) were detected.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.165-173
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• 2014

The method of emission inspection for Heavy-duty diesel vehicles has been engine speed type Lug-down 3mode. This method could bring damage to decrepit vehicles under high speed and high load condition and it could not apply the driving pattern on the road. For these reasons, this study has started to create new emission inspection which is appropriate for Korea's road infrastructure. KD 147 would be applied to light-duty diesel vehicles from july 2010 after model operations. Therefore, this study has investigated new emission inspection system for heavy-duty diesel vehicles, except for light-duty diesel vehicles. In consideration of domestic conditions to meet the new load test method in this study, the Lug-down3 mode vehicle speed method was developed for the first time in korea.