• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.1653-1661
• /
• 2008

A trial run of locally-developed tilting train has been in process on Chungbuk line since the test vehicle was first produced. For the system stabilization, interface verification among the systems including track, structure, catenary and signaling system, not to mention the rolling stock, is very crucial. In the area of wayside structure, the stability of track structure and train run shall be evaluated through the review of impact by increased speed by developed train on track structure. The study thus was intended to evaluate the impact on track while a tilting train is running the conventional line(ballast track), which is vulnerable to accelerated train speed. The evaluation of tilting train test running the part of Honam line was conducted to identify the impact on existing track performance by tilting train. To identify the performance of each part of track components while tilting train and high speed train were running the existing line, wheel load, rail bending stress, vertical displacement of rail and sleeper were compared so as to evaluate the expected impact by tilting train for improving the train speed.

• Journal of Internet of Things and Convergence
• /
• v.8 no.6
• /
• pp.55-63
• /
• 2022

In recent years, with the rapid development of large and medium-sized urban rail transit in China, the total operating mileage of high-speed railway and the total number of EMUs(Electric Multiple Units) are rising. The system complexity of high-speed EMU is constantly increasing, which puts forward higher requirements for the safety of equipment and the efficiency of maintenance.At present, the maintenance mode of high-speed EMU in China still adopts the post maintenance method based on planned maintenance and fault maintenance, which leads to insufficient or excessive maintenance, reduces the efficiency of equipment fault handling, and increases the maintenance cost. Based on the intelligent operation and maintenance technology of PHM(prognostics and health management). This thesis builds an integrated PHM platform of "vehicle system-communication system-ground system" by integrating multi-source heterogeneous data of different scenarios of high-speed EMU, and combines the equipment fault mechanism with artificial intelligence algorithms to build a fault prediction model for traction motors of high-speed EMU.Reliable fault prediction and accurate maintenance shall be carried out in advance to ensure safe and efficient operation of high-speed EMU.

• Applied Chemistry for Engineering
• /
• v.34 no.1
• /
• pp.69-74
• /
• 2023

As a chemical de-icing method, propylene glycol de-icing fluid is applicable for melting ice caused by snow and ice adhering to the lower part of high-speed rail rolling stock and bogie parts in winter. By spraying propylene-glycol de-icing fluid on high-speed rail rolling stock and bogie parts in advance to minimize snow adhesion, ice-melting efficiency can be further improved. In the case of high-speed rail rolling stock, even if propylene-glycol de-icing fluid is sprayed, the anti-icing performance is poor because the fluid is almost lost on the surface of the vehicle when operating at high speed. In this study, in order to prevent freezing caused by snow and ice adhering to the lower part of high-speed rail rolling stock and bogie parts, we have investigated the properties of propylene-glycol de/anti-icing fluid containing water-repellent agents that prevent surface freezing. We tried to find the optimal component for de/anti-icing fluid for high-speed rail rolling stock by evaluating the ice melting performance, contact angle, and anti-icing performance according to the types of water-repellent agent. As a result of the evaluation, it was confirmed that an de/anti-icing fluid containing an ethoxysilane-type water repellent agent was most suitable.

• Journal of Broadcast Engineering
• /
• v.18 no.4
• /
• pp.535-542
• /
• 2013

In this paper, we proposed a advanced hardware engine architecture for high speed and high detection rate image recognitions. We adopted the HOG-LBP feature extraction algorithm and more parallelized architecture in order to achieve higher detection rate and high throughput. As a simulation result, the designed engine which can search about 90 frames per second detects 97.7% of pedestrians when false positive per window is $10^{-4}$.

• Journal of computational fluids engineering
• /
• v.19 no.1
• /
• pp.7-14
• /
• 2014

Aerothermodynamic characteristics of re-entry vehicles in hypersonic speed regimes are investigated by applying CFD methods based on the Navier-Stokes-Fourier equations. A special emphasis is placed on the effects of high temperature chemically reacting gases on shock stand-off distance and thermal characteristics of the flowfields. A ten species model is used for describing the kinetic mechanism for high temperature air. In particular, the hypersonic flows around a cylinder are computed with and without chemically reacting effects. It is shown that, when the chemically reacting effects are taken into account, the shock stand-off distance and temperature are significantly reduced.

• Smart Media Journal
• /
• v.3 no.3
• /
• pp.46-50
• /
• 2014

Nowadays, mobile devices such as smartphones and tablet PC's are making big changes in our life. The most widely used mobile operating systems are Google's Android, Apple's iOS and Microsoft's Windows Mobile. Among them, Android has been researched in various electronic fields such as smartphones and tablet PC's as well as automobiles, Media oriented systems transport(MOST) is a standard for high-speed multimedia communications in automotive industries. In this paper, we present the design results of in-vehicle infotainment software using MOST network based on Android.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.6
• /
• pp.61-66
• /
• 2012

Conventional method to transform vehicle driving condition to engine operation mode is to use vehicle road load under neutral gear and mechanical efficiency of drivetrain. But this method requires additional measurement of efficiency of drivetrain on a test rig. And this measurement is normally done at fixed speed and thus estimated accuracy of engine operation mode is not considered to be high enough. This study suggests new method to calculate engine operation mode for prescribed driving mode such as NEDC using vehicle coastdown test under gear engaged condition without measurement of mechanical efficiency of drivetrain. Coastdown test was done under neutral and gear engaged condition for comparison and also trial to extract mechanical loss of drivetrain was carried out. Calculated engine torque by conventional and newly suggested method was compared with actually measured torque of a vehicle on a chassis dynamometer during NEDC. Newly suggested method showed slightly higher accuracy of accumulated brake work during NEDC.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.589-594
• /
• 2004

In design of suspension system for KHST, it was applied the approximated optimization method using meta-models which called Response Surface Model and Neural Network Model for 29 design variables and 46 performance index. These models was coded using correlation between design variables and performance indices that is made by the 66 times iterative execution through the design of experimental table consisted orthogonal array L32 and D-Optimal design table. The results show that the optimization process is very efficient and simply applicable for complex mechanical system such as railway vehicle system. Also it was compared with the sensitivity of some design variables in order to know the characteristics of two models. This paper describes the general method for dynamic analysis and design process of railway vehicle system applied to KHST development, and proposed the efficient methods for vibration mode analysis process dealing with test data and the function based approximation method using meta-model applicable for a complex mechanical system. This method will be able to apply to the other railway vehicle system in oder to systematize and generalize the design process of railway vehicle dynamic system.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.58-61
• /
• 2006

The effect of the steel ratio on the behavior of continuously reinforced concrete pavement (CRCP) under moving wheel loads and environmental loads were investigated in this study. The CRCP sections having different steel ratios of 0.6, 0.7, and 0.8% were considered: (1) to evaluate the load transfer efficiency (LTE) at transverse cracks; (2) to investigate strains in CRCP when the system is subjected to moving vehicle loads; (3) and to investigate the time histories of the crack spacing variations. The LTEs were obtained by conducting the falling weight deflectometer (FWD) tests. The strains in the concrete slab and the bond braker layer under moving vehicle loads were obtained using embedded strain gages. The results of this study show that the LTEs at transverse cracks are very high and not affected by the steel ratio. The strains in CRCP under vehicle loads become smaller as the vehicle speed increases or as the wandering distance increases; however, the strains are not clearly affected by the steel ratio. However, the changes in the crack spacings are affected by the steel ratio.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1708-1713
• /
• 2003

The acceptance test of KTX has been performed in Korea. During the test, lateral vibration of carbody over the accepted value called swat was found. KTX has 20 car trainsed formation whose trailer cars are linked by articulate bogies. So this study is performed to see the effects of long trainsed formation on vehicle dynamics and the train stability by 20 car vehicle model. Firstly the reliable vehicle model which shows well the tendencies appeared in the tests on the high speed test line is required to find the cause of lateral vibration and the countermeasure. Vehicle model was made for the analysis with VAMPIRE. The analysis results show that secondary air spring lateral stiffness is the most significant parameter to cause carbody lateral vibration. Mode analysis results show that he least damped mode shape is similar to the vibration pattern shown in the tests that the amplitude of the motion increases along the train set and decreases in the tail part. For the case of short train formation with 7 or 10cars, sway does not happen. But in the case of longer train formation with 16 or 20 cars, sway was found.