• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1999-2004
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• 2009

Since 2003, the domestic ground signalling system of the Kyeongbu and Honam lines has been steadily improving with the introduction of the ATP system and application of the system to the train is actively being pursued for 2009 target. Therefore, new ground signalling systems are being installed to the trains and track conditions to control the train speed to a maximum of either 80km/h, 120km/h, 150km/h, or 160km/h. As well, considering safe breaking distance, block signalling has been installed and also the change over times of the track switching device has been adjusted according to the train speed. Since the new Tilting trains will be running faster than present trains, at speeds over 180 km/h, we anticipate that there will be problems with present signalling facilities. Therefore this paper attempts to examine the various problems with the interface between the ATP signalling system and the new Tilting trains and also it will propose the most effective operating plan based upon case studies of successful foreign operations.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.172-183
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• 1998

The purpose of this study is to reduce the number of employees hired by Seoul Metropolitan Subway Corporation(SMSC) as a way of responding to deteriorating financial deficit problem. For the reduction, the personnel structure of Seoul Metro Rapid Transit Subway(SMRTS) newly founded in 1995 is benchmarked. Several assumptions are set for seeking the persuasive alternative; 1) no compulsory reduction of existing personnel, 2) raising the salary of SMSC to the same level of SMRTS for compensating intensified work burden, 3) hiring new employees to the amount of one-third of the reduced workforce for minimizing the problems associated with the reduction. The study suggests that the personnel reduction in relevant parts be planned in the following ways; 1) passenger transport part: from daily 3 shifts of 4 group to 2 shifts of 3 group, 2) fleet inspection, civil d: electric engineering, railtrack maintenance, signal parts: from 12 day-off to 10day-off, 3) architecture, AFC parts: from 2 shifts of 3 group to daily work, 4) fleet maintenance, architecture parts: expanding out-sourcing ＆ automation, and 5) headquarter part: 10% reduction of the total of office workers. The study finds, by implementing the plan, that 1,270 employee can be reduced, and that aggregate 106.8 billion won will be saved for the next 10 years.

• 산업공학
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• 제16권spc호
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• pp.111-115
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• 2003

Railroad system is consisted of resources of rail track, signal system, and vehicles. Railway operation must use these limited resources and maximize resource utilization. Line capacity(number of trains throughput/day) is determined by such as parameters, line utilization rate($\alpha$), dummy rate for the break-through hour($\beta$), and dummy rate for the number of rail track intervals($\delta$). Line capacity simulation(LCS) determined the line capacity through simulation given $\alpha$, $\beta$, and $\delta$. This paper deals with the development of parameter evaluation simulation(PES). PES presents the decision maker with the relationship of line capacity and measurement of robustness for various scenarios in different parameters and then the decision maker can determine the appropriate parameters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1136-1139
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• 2000

The paper describes a new and rigorous mathematical model for the rotor field oriented system with induction motor which uses the estimated speed and rotor flux based on a Model Reference Adaptive System, as well as the real-time approach. The estimated speed and rotor flux is used for the speed and flux feedback control. The stability and the convergence of the estimator are improved on the basis of hyperstability theory for non-linear systems. The real-time controller and estimator are implemented with a sampling period of $926{\mu}s$ using a dual TMS320C44 floating-point digital signal processor. The validity of the proposed method is verified by simulation, and also, the sensorless control was tested on the propulsion system simulator, used for the development of Korean High-Speed Railway Train (KHSRT) [5].

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.941-946
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• 2006

It followed in system development and SMRT(Seoul Metropolitan Rapid Transit Co)System reached to an automatic train operation(ATO) and driverless operation(DLM) from the manual operation due to the train driver. The train like the general bus or the car vehicle was not serial riding in a car and the Parallel concept which the numerous passenger rides in a car simultaneously occur frequently the charge of the train driver unmanned bitterly from existing manual handling was a possibility of doing, train open door control(ODM) which bites also ATO, it handles it minimized. Like this ATO/DLM, the control system which bites being a Wayside to Train communication for immediacy, it is a system of the Vital concept the immediacy of the citizen Data evil the radio information transmission and the train of the interface which is accurate from unmanned operation and, will decipher, will accomplish it will guarantee. It respects the passenger accident prevention and an air question environment improvement from subway platform and phul leys the screen door of Platform(PSD) with the fire tube frost it refers and part it treats and to sleep it does, ODM which bites is accuracy and immediacy of altitude and when seeing from the viewpoint which demands the trust of altitude, ODM system the trust of car incest interface in the equipment construction which is safe and the comparative analysis back of the system analysis against the control which bites and case study and other subway system it leads from the research which it sees and signal - train in base grudge to sleep it contributes it does.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.499-503
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• 2009

In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated from an electrical response point of view. To analysis power line disturbance by induced contact loss phenomenon for high speed operation, a hardware Simulator which considered contact loss between contact wire and the pantograph as well as contact wire deviation is developed. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that an arc phenomenon by loss of contact brings out EMI. In case of a high-speed train using electrical power, as comparison with diesel rolling stock, PLD(Power Line Disturbance) such as harmonic, transient voltage and current, EMI, dummy signal injection etc usually occurs. Throughout experiment, it is verified that an arc phenomenon is brought out for simulator operation and consequently conducted noise is flowed in electric circuit by power line disturbance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1270-1278
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• 2008

A great deal of development has been made in the field of railroad control in Korea. Like the recent High speed railroad (KTX) and the intercity light rail train (LRT) are being vigorously promoted. Therefore, in concert with the new railroad development projects, improved train control technics are being applied. Along with the focus on these newly developed advanced technologies the need for a reliable safety system for the safety of the passengers and railroad control personnel alike is being intensified. New safety facilities are continuously being developed in order to safely introduce and develop these new technologies. There is an urgent need for research and development of safety facilities for the implementation of the presently developed facilities as well as for the presently being used. Therefore, this research will study the safe operation of Korean railroad and the implementation situation of the class, functionality, ensured safety range etc. of the safety facilities for users and operators. In studying the material of the kinds of implemented safety facilities and technologies being used abroad we have researched into the most suitable direction of development of safety facilities for the Korean railroad environment.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1454-1462
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• 2008

This paper is focused on the analysis of the noise and vibration measured near the wheelset of the high-speed trains using a time-varying frequency transform as a preliminary research of running monitoring. Due to the non-stationary characteristics, it is necessary to examine noise and vibration of the train with time-varying frequency transforms. In this paper, the short-time Fourier transform method is utilized - the stored data is localized by modulating with a window function, and Fourier transform is taken to each localized data. For the examination, the non-stationary noise and vibration of the high-speed train's wheelset are measured by using some microphones and accelerometers, and those signals are stored in a on-board data acquisition system. The non-stationary random signal analyses with the short-time Fourier transform are performed, and the result are classified as follows; auto-spectral density, cross-spectral density, frequency response, and coherence functions. From those functions, it is possible to observe the frequency characteristics of sleepers, switchers, tunnels, and steel bridges. Also, some distinct peaks, which are not dependent upon the train's speed, are identified from the results.

• 한국멀티미디어학회논문지
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• 제25권11호
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• pp.1547-1556
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• 2022

As mechanical facilities are interacting with each other, the failure of some equipment can affect the entire system, so it is necessary to quickly detect and diagnose the abnormality of mechanical equipment. This study proposes a deep learning model that can effectively diagnose abnormalities in rotating machinery and equipment. CNN is widely used for feature extraction and LSTMs are known to be effective in learning sequential information. In LSTM, the number of parameters and learning time increase as the length of input data increases. In this study, we propose a method of segmenting an input segment signal into shorter-length sub-segment signals, sequentially inputting them to CNN through a time-distributed method for extracting features, and inputting them into LSTM. A failure diagnosis test was performed using the vibration data collected from the motor for ventilation equipment installed at the urban railway station. The experiment showed an accuracy of 99.784% in fault diagnosis. It shows that the proposed method is effective in the fault diagnosis of rotating machinery and equipment.

• Structural Engineering and Mechanics
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• 제77권4호
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• pp.495-508
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• 2021

This study devises a novel approach, namely quadruple 1D convolutional neural network, for detecting connection stiffness reduction in steel truss bridge structure using experimental and numerical modal data. The method is developed based on expertise in two domains: firstly, in Structural Health Monitoring, the mode shapes and its high-order derivatives, including second, third, and fourth derivatives, are accurate indicators in assessing damages. Secondly, in the Machine Learning literature, the deep convolutional neural networks are able to extract relevant features from input data, then perform classification tasks with high accuracy and reduced time complexity. The efficacy and effectiveness of the present method are supported through an extensive case study with the railway Nam O bridge. It delivers highly accurate results in assessing damage localization and damage severity for single as well as multiple damage scenarios. In addition, the robustness of this method is tested with the presence of white noise reflecting unavoidable uncertainties in signal processing and modeling in reality. The proposed approach is able to provide stable results with data corrupted by noise up to 10%.