• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1067-1068
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• 2008

The Operation of high speed train in year 2004 bring about a great change in railroad industry. Especially in railroad construction field we have acquired great Know-how. And up to now we are building up operation skills. But the high speed train system are totally imported, so it is necessary to investigate some of the equipment based on our own environment. In case of Toughened Glass Stem Insulator, we don't have any application case in domestic and limited in abroad. So there must be some characteristic estimation. The estimation was made in three different ways. First electrical field cause, Second physical field cause and finally in circumstance cause. In Electrical field cause, amplitude and number of time for abnormal peak voltage data are collected. And in physical field cause, amplitude and trend of vibration in to the insulator are examined. And I circumstance cause, possibility of flying gravel and ice clod are investigated. Through this basic data suitability for Toughened Glass Stem Insulator using in domestic will be accumulated.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.324-333
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• 2014

In this study, physiological status of locomotive engineers were measured through EEG, ECG, EDA, PPG and respiration signals from 6 subjects to evaluate their arousal status during train operating. Existence of tunnels and mechanical vibration of train using 3-axes acceleration sensors were recorded simultaneously and were correlated with operator's physiological status. As the result of the analyzed subjects' physiological signals, mean SCR was increased in the section where more body movement is required. The RR interval was decreased before and after train stop due to the higher level of mental tension. The intensity of beta wave of EEG was found to be higher before and after train stop and tunnel section due to the increased mental arousal and tension. Therefore, it is expected that the outcomes of the physiological signals explored in this study can be utilized as the quantitative assessment methods for the arousal status to be used for sleepiness prevention system for vehicles operators which can greatly contribute to public transportation system safety.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.423-427
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• 2008

The Operation of high speed train in year 2004 bring about a great change in railroad industry. Especially in railroad construction field we have acquired great Know-how. And up to now we are building up operation skills. But the high speed train system are totally imported, so it is necessary to investigate some of the equipment based on our own environment. In case of Toughened Glass Stem Insulator, we don't have any application case in domestic and limited in abroad. So there must be some characteristic estimation. The estimation was made in three different ways. First electrical field cause, Second physical field cause and finally in circumstance cause. In Electrical field cause, amplitude and number of time for abnormal peak voltage data are collected. And in physical field cause, amplitude and trend of vibration in to the insulator are examined. And I circumstance cause, possibility of flying gravel and ice clod are investigated. Through this basic data suitability for Toughened Glass Stem Insulator using in domestic will be accumulated.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.140-143
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• 2008

The Operation of high speed train in year 2004 bring about a great change in railroad industry. Especially in railroad construction field we have acquired great Know-how. And up to now we are building up operation skills. But the high speed train system are totally imported, so it is necessary to investigate some of the equipment based on our own environment. In case of Toughened Glass Stem Insulator, we don't have any application case in domestic and limited in abroad. So there must be some characteristic estimation. This paper introduces estimation methode in three different field. First electrical field, Second physical field and finally environment circumstance. In Electrical field, amplitude and number of time for abnormal peak voltage data are collected. And in physical field case, amplitude and trend of vibration in to the insulator are examined. And I circumstance case, possibility of flying gravel and ice clod are investigated. Through this basic data, suitability for Toughened Glass Stem Insulator using in domestic will be accumulated and estimated.

• Smart Structures and Systems
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• v.29 no.2
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• pp.361-374
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• 2022

As civil infrastructure has continued to age worldwide, its structural integrity has been threatened owing to material deteriorations and continual loadings from the external environment. Structural Health Monitoring (SHM) has emerged as a cost-efficient method for ensuring structural safety and durability. As SHM research has gradually addressed an increasing number of structure-related problems, it has become difficult to understand the changing research topic trends. Although previous review papers have analyzed research trends on specific SHM topics, these studies have faced challenges in providing (1) consistent insights regarding macroscopic SHM research trends, (2) empirical evidence for research topic changes in overall SHM fields, and (3) methodological validations for the insights. To overcome these challenges, this study proposes a framework tailored to capturing the trends of research topics in SHM through a bibliometric and network analysis. The framework is applied to track SHM research topics over 15 years by identifying both quantitative and relational changes in the author keywords provided from representative SHM journals. The results of this study confirm that overall SHM research has become diversified and multi-disciplinary. Especially, the rapidly growing research topics are tightly related to applying machine learning and computer vision techniques to solve SHM-related issues. In addition, the research topic network indicates that damage detection and vibration control have been both steadily and actively studied in SHM research.

• Journal of Environmental Impact Assessment
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• v.23 no.6
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• pp.517-526
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• 2014

This paper performed studies on a guide for an environmental assessment necessary to select railroad route optimally, and presented techniques for an environmental friendly route selection using AHP(Analytical Hierarchy Process) as an objective method. The AHP is an approach to decision making that involves multiple choice criteria into a hierarchy and assessing the relative importance of each criterion, and determining an overall ranking of the alternatives. For the purpose of this study, we established the weight and the order of major environmental assessment items based on the survey of experts. The results of the weight by AHP were in order of Fauna & Flora, Topography & Geology, Nature Environmental Assets, Noise & Vibration, Water Quality, Landscape and Air Quality indicating natural environment should be in priority. To develop the more efficient environmental friendly route selection systems, it is necessary to consider economical, technical, and social aspects in addition to environmental consideration.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.129-134
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• 2009

To ensure the safety and functionality of a railroad bridge, maintaining the integrity of the bridge via continuous structural health monitoring is important. However, most structural integrity monitoring methods proposed to date are based on modal responses which require the extracting process and have limited availability. In this paper, the applicability of the existing damage identification method based on free-vibration reponses to time-domain deflection shapes due to moving train load is investigated. Since the proposed method directly utilizes the time-domain responses of the structure due to the moving vehicles, the extracting process for modal responses can be avoided, and the applicability of structural health evaluation can be enhanced. The feasibility of the presented method is verified via a numerical example of a simple plate girder bridge.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.46-53
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• 2016

LED light sources have been known to have a long life and good energy efficiency compared to traditional light sources. Recently, headlamps using LED light sources have ensured the forward visibility and safe operation of high-speed rolling stock. However, assessing the lifespan of LED headlamps based on real test data is not easy because it depends on the multiple stress factors such as a fixed driving current, junction temperature, vibration and so on. Generally, LED headlamps have failed before their advertised life span mainly due to temperature. Thus, the performance assessment of a temperature control unit should be done before a life cycle test of LED headlamps. This study attempted to develop a prototype temperature control module for a lifecycle test system using a commercial LED headlight and verified the system through experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7941-7948
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• 2015

Rolling noises during train operation are caused by vibration excited from irregularities of surface roughness between wheel and rail. Therefore, a proper measurement and analysis techniques of acoustic roughness between wheel and rail surface are required for transmission, prediction, and analysis of the train rolling noise. However, since current measuring devices and methods use trolley-based manual handling devices, the measurements induce unstable measuring speed and vibrational interface that increases errors and disturbances. In this paper, a new automatic rail surface exploring platform with a speed controller has been developed for improving measurement accuracy and reducing inconsistency of measurements. In addition, we propose a data integration method of the rail surface roughness with multiple homogeneous displacement sensors and verified the accuracy of the integrated data through standard test-bed railway track investigation.

• Explosives and Blasting
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• v.40 no.2
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• pp.25-34
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• 2022

Recently, there has been an increasing number of cases of improving constructability by using electronic detonators with precise delay time in tunnel blasting sites. This case is a case of conducting test blasting using with non-electric detonator and electronic detonator at the site of 『Seoul Metropolitan Area Express Railroad Route A Private Investment Project Section 00』 that requires careful management of vibration and noise. Although this site was designed with a non-electric detonator, it was attempted to improve the advance rate and control vibration and noise by mixing the non-electric detonator and the electronic detonator due to the decrease in the advance rate. As a result of the blasting, the target value was achieved with an advance rate of about 85% and a maximum measured value of vibration and noise is 0.215cm/sec and 73.22dB(A) which were measured below regulatory standards. As blasting works in downtown areas, it is necessary to designate measurement and management objects to continuously manage vibration and noise.