• Journal of the Korean Society for Railway
• /
• v.14 no.6
• /
• pp.507-514
• /
• 2011

Recently, we developed a new subway train with many cooperative companies. The main controller of the subway train is Control and Monitoring System (TCMS), so we conducted requirement analysis of TCMS considering system performance, easy maintenance and service oriented flexibility. Hence, we adopted new bus architecture and QNX as a Real-time Operating System (RTOS) and developed hardware systems. The functions of TCMS are employed into two computers, service computer and control/monitor computer, to increase on their performance and to yield easy maintenance and to satisfy customer needs. The TCMS controls and monitors control devices equipped in the train through various protocols which are implemented in hardware. In order to evaluate the performance of the system and to satisfy reliability, various experiments including EMC/ECI were performed. Now the TCMS is installed on the newly developed train and is under performance evaluation through test driving.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.2
• /
• pp.40-48
• /
• 2016

To observe the rail-slab interaction in continuous welded railway(CWR) bridge when earthquake occurs, additional axial rail stresses and relative longitudinal displacements between rail and bridge deck were calculated with input of various load combinations and 3 different types of seismic loads to an analytical model. As results of analysis, it can be found that standard response spectrum proposed by Korea Rail(KR) network authority for earthquake design showed less additional axial rail stresses than allowable levels, but greater relative longitudinal displacement between rail and bridge deck, which means that adjustment of relative longitudinal displacement within a standard level is much more difficult than axial train stress. Additionally, if a large-scaled earthquake as occurred at Kobe, Japan comes up, then both of additional axial rail stress and relative displacement in rail-bridge deck may exceed allowable levels, which indicates to make proper design guides against sudden earthquake occurrence.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.4
• /
• pp.149-158
• /
• 2003

It is customary that tendons and sectional dimensions are calibrated and tendon forces are applied at once at the initial stage to keep the subsequent stresses occuring at different loading stages within the allowable stresse in prestressed concrete (PSC) bridge design. However, this traditional tensioning method usually results in a too conservative sectional depth in view of ultimate capacity of a girder. A new design method which can realize the reduction of sectional depth of PSC girder is theoretically suggested in this study. Tendons are tensioned twice at different loading stages: the initial stage and the stage after fresh slab concrete is cast. It can be shown that according to this technique, sectional depth can be significantly reduced and larger span can be realized compared to traditional ones. In this paper, there is an example about the design of bridge by means of new PSC design theory, having a longer span than a existing railway bridge. Also, a new method by continuous tendon profiles is presented to be continuous a IPC bridge.

• Journal of Wetlands Research
• /
• v.20 no.4
• /
• pp.424-431
• /
• 2018

Stormwater runoff containing considerable amounts of pollutants such as particulates, organics, nutrients, and heavy metals contaminate natural bodies of water. At present, best management practices (BMP) intended to reduce the volume and treat pollutants from stormwater runoff were devised to serve as cost-effective measures of stormwater management. However, improper design and lack of proper maintenance can lead to degradation of the facility, making it unable to perform its intended function. This study evaluated an infiltration trench (IT) that went through a series of maintenance operations. 41 monitored rainfall events from 2009 to 2016 were used to evaluate the pollutant removal capabilities of the IT. Assessment of the water quality and hydrological data revealed that the inflow volume was the most relative factor affecting the unit pollutant loads (UPL) entering the facility. Seasonal variations also affected the pollutant removal capabilities of the IT. During the summer season, the increased rainfall depths and runoff volumes diminished the pollutant removal efficiency (RE) of the facility due to increased volumes that washed off larger pollutant loads and caused the IT to overflow. Moreover, the system also exhibited reduced pollutant RE for the winter season due to frozen media layers and chemical-related mechanisms impacted by the low winter temperature. Maintenance operations also posed considerable effects of the performance of the IT. During the first two years of operation, the IT exhibited a decrease in pollutant RE due to aging and lack of proper maintenance. However, some events also showed reduced pollutant RE succeeding the maintenance as a result of disturbed sediments that were not removed from the geotextile. Ultimately, the presented effects of maintenance operations in relation to the pollutant RE of the system may lead to the optimization of maintenance schedules and procedures for BMP of same structure.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1134-1141
• /
• 2011

Costs have long since become a major issue in railway system analysis, attention is not limited to the acquisition costs alone, but encompasses all costs involved in the use and disposal of the systems. Concepts such as Life Cycle Cost(LCC), Costs Of Ownership(COO), or Total Ownership Cost(TOC) are more and more frequent in any document dealing with system analysis. Most of railway projects have applied this LCC Model to evaluate effectiveness of system acquisition cost. But these action of LCC model does not applied all the rest of system life cycle period due to the differences of its responsibility. This is why a study has been undertaken by the operation party to harmonize the most important aspects of the LCC model. This study focused on these and other objectives for introduction of method and needs for an action plan for maintenance actions involved relevant cost allocation.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1650-1655
• /
• 2010

This paper presents an activation plan for reliability centered maintenance (RCM) of rolling stock. The KTX is carrying out the maintenance in compliance with RCM. MKBSF, that is one of the reliability indices for KTX, is shown 183,483 km in 2009, whereas it is shown 68,986 km in 2004. It means that the reliability of KTX has been growing every year. It also is result of reliability management activities. KORAIL did not apply RCM until now about the conventional rolling stocks. But KORAIL decided that applies RCM system because of reliability management effect of KTX. In this study, we tried to know an activation plan for the reliability centered maintenance of the conventional rolling stocks.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.1350-1358
• /
• 2008

Recently the study related to life cycle cost analysis of railway structure consisted of a complex is proceeded covering several range, which is considering the methodology of efficiency and rationalization for maintenance and analysing long-time behavior of the structure of looking at standpoint from asset management and safety. But LCCA(life cycle cost analysis) of railway structure was almost impossible as there were not anything datum for maintenance plan, such as maintenance periods related to each of components(painting and corrosion of steel, and cracking of elements, etc)and maintenance proportion, despite of its 100-year history. According, for collecting data related to railway truss bridge, bridge record cards and testing safety papers, and researching question, etc are surveyed and classified for LCC Analysis. Especially, LCC assessment on the side of assets-maintenance considering about initial cost, maintenance cost, and indirect cost is constructed. Maintenance period and complementary measure rate are very important in maintenance. To decide maintenance period, Baysian updating method is applied.

• Proceedings of the KSR Conference
• /
• 2002.10a
• /
• pp.238-243
• /
• 2002

The maintenance CALS system for car of urban transit is a part of standardization and development of urban transit system, and We have been performed the establishment of maintenance CALS system from 2001 to 2005. These 2D and 3D configuration management system are utilized in a variety of CALS system for user's convenience and safety in maintenance. In this paper, the 2D and 3D configuration system will be discussed for necessity and possibility. This system include RAMS(reliability, availability, maintainability and safety) of the vehicles shall be enhanced in the future.

• Journal of the Korea Convergence Society
• /
• v.12 no.4
• /
• pp.1-8
• /
• 2021

Currently, lithium-ion batteries are mainly used in energy storage equipment products including automobiles. This can be exposed to dangerous situations such as explosions in the event of incorrect battery management conditions that are overcharged or left in high temperature conditions. It also causes a situation battery cannot be used when it has been over discharged. Therefore, a system that manages the state of the battery is required. The battery management system aims to obtain optimum battery efficiency by accurately recognizing the state of the battery and keeping the voltage of each cell constant. In this paper, we develop a lithium-iron phosphate battery that has higher safety than a general lithium-ion battery. Then, in order to manage this, we try to develop the algorithm of the BMS module based on the Bluetooth communication using the MATLAB-SIMULINK.

• Journal of Korea Society of Industrial Information Systems
• /
• v.23 no.6
• /
• pp.67-77
• /
• 2018

Currently, there are many problems due to the decline in school-age population. Moreover, Korea has the largest number of universities compared to the population, and the university enrollment rate is also the highest in the world. As a result, the minimum student retention rate required for the survival of each university is becoming increasingly important. The purpose of this study was to examine the effects of reducing the number of graduates of education and the social climate that prioritizes employment. And to determine what the basic direction is for students to manage the student retention rate, which can be maintained from admission to graduation, to determine the optimal input variables, Based on the input parameters, we will make associative analysis using apriori algorithm to collect training data that is most suitable for maintenance rate management and make base data for development of the most efficient Deep Learning module based on it. The accuracy of Deep Learning was 75%, which is a measure of graduation using decision trees. In decision tree, factors that determine whether to graduate are graduated from general high school and students who are female and high in residence in urban area have high probability of graduation. As a result, the Deep Learning module developed rather than the decision tree was identified as a model for evaluating the graduation of students more efficiently.