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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Railway
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Journal DOI :
Korean Society for Railway
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Volume & Issues
Volume 12, Issue 6 - Dec 2009
Volume 12, Issue 5 - Oct 2009
Volume 12, Issue 4 - Aug 2009
Volume 12, Issue 3 - Jun 2009
Volume 12, Issue 2 - Apr 2009
Volume 12, Issue 1 - Feb 2009
Selecting the target year
Ballast Flying Probability Analysis for Ballast Types and Underbody Flow Conditions
Rho, Joo-Hyun ; Ku, Yo-Cheon ; Yun, Su-Hwan ; Park, Hoon-Il ; Kwon, Hyeuk-Bin ; Lee, Dong-Ho ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 829~834
A ballast-flying probabilitie is suggested for various ballast types, heighter types and underbody flow conditions as train speeds. The average speed of measured points is converted to the ballast-flying probabilities of BFPF which come from wind tunnel test data. Underbody flow fields are numerically simulated for the various conditions. The results show that the ballast-flying probability is steeply increased as train speed increased, and reaches a value of 87% at 350 km/h train speed. And the differences of probabilities among the ballast shapes are considerably high. The upper surface of heighter or tie is most probable area. Through this study, the ballast-flying Sensitivities with heighter was defined to understand the characteristics of ballast-flying probability on various conditions. And the ballast-flying probability can be reduced by the heighter.
Determination on the Reinforced Roadbed Thickness of Concrete Track at Embankment Section
Lee, Il-Wha ; Lee, Sung-Jin ; Sin, Min-Ho ; Hwang, Sun-Kun ; Lee, Chang-Jin ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 835~843
Recently the more stable roadbed is required due to the high speed and design load. Therefore the reinforced roadbed was introduced as the solution. But the thickness and stiffness of reinforced roadbed in design code is being conservatively assessed by the foreign code without considering the domestic construction condition. In this paper, adequate Young's modulus, drain capacity, freezing depth, economical efficiency, bearing capacity, construction condition and 3-D finite element method were employed to determine the proper thickness of reinforced roadbed at the embankment section.
A Study on the Relationship between Vertical Separation and Operational Efficiency of Railway Industry
Kim, Seong-Ho ; Choi, Tae-Sung ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 844~851
Since 1990s, the European railway sector has undergone both a vertical separation and a vertical integration. Recently Simar and Wilson (2008) provides a bootstrap test procedure for testing whether two groups' mean efficiencies are equivalent. The purpose of this paper is to ascertain the relationship between vertical separation and operational efficiency of railway industry using the Simar and Wilson's bootstrap test procedure not used in previous studies with a data set of 20 European countries from 1998 to 2005. From the value of test statistic it seems that the mean operational efficiencies of vertically separated railway industry were higher than those of vertically integrated railway industry. However the p-value indicates that the differences of mean operational efficiencies are not significat at any meaningful level.
A Study on the Reliability Management of Onboard Signaling Equipment for the Korean Tilting Train
Shin, Duck-O ; Baek, Jong-Hyun ; Lee, Knag-Me ; Kim, Yong-Kyu ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 852~858
This paper is a study on the reliability management of onboard signaling equipment for the Koran Tilting Train (TTX) to run the existing railway to express railway. For safe running of tilting train which operates at Automatic Train Protection (ATP) and Automatic Train Stop (ATS), a reliability management plan for TTX onboard is proposed for preventing train safety from driver oversight and malfunction by establishing braking curves based on movement authority and speed limit, according to preceding train location and rail conditions. Also, reliability of TTX onboard equipment on the basis of proposed plan was estimated, and actual case studies based on the international requirements IEC 62278 (EN 50126) were provided to verify its reliability.
A Study on the Running Safety by F26 Turnout and Vehicle Model
Kim, Sung-Jong ; Lee, Hi-Sung ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 859~864
When the vehicle passes through turnout, the design is required to minimize the change of lateral force. Therefore, in case the vehicle passed the through turnout, we ought to execute dynamic analysis of the interaction between the vehicle and turnout in order to make an estimate of the lateral force and the derailment coefficient on the turnout. In this paper, we established the analytical model of the vehicle and turnout and analysed running safety when the vehicle passes through turnout in order to improve running safety of the vehicle on turnout. Also, to verify the vehicle and turnout model, we analysed reaction force and running behavior between wheel and rail, and running safety of the vehicle by changing cradle part and the tongue rail when the vehicle passes through turnout.
Experiments on Egress of Persons with Mobile Disability in Train Car
Kim, Jong-Hoon ; Kim, Woon-Hyung ; Roh, Sam-Kew ; Lee, Duck-Hee ; Jung, Woo-Sung ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 865~872
Korean railroad company is continuously improving the service for the disabled. They also install and reform many facilities for them. However, It is not considered the importance of egress when fire occurred in a cabin Now, Fire hazard analysis and risk assessment are introduced into domestic regulations for improving fire safety performance of train car and railroad facilities. Considering the fact that fire safety evaluation process doesn't fully include disabled person, fundamental egress data for them is very important for life safety aspect. In this paper, Egress experiments and analysis were conducted to measure the movement speed of the disabled with Mugunghwa and Saemaul.
Railway System Standby Power Nickel Metal Hydride Battery
Kim, Sung-Yong ; Park, Dong-Pil ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 873~877
In order to use railway system standby power, produced 160Ah NiMH battery that would be able to substitute the lead acid battery or NiCd battery form which contain the toxic material in environment, using parallel connected 80Ah NiMH battery. And in order to develop proper electrode in the 160Ah NiMH battery, tested high rate discharge performance of the ternary electrolyte. 160Ah NiMH battery evaluated the various test in order to use railway system standby power.
A GA-Based Algorithm for Generating a Train Speed Profile Optimizing Energy Efficiency
Kang, Moon-Ho ; Han, Moon-Seob ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 878~886
This paper proposes an optimal algorithm for generating a train speed profile giving optimal energy efficiency based on GA (Genetic Algorithm) and shows its effectiveness with simulations. After simplifying the train operation mode to a maximum traction, a coasting and a maximum breaking, adjusting the coasting point to minimize the train consuming energy is the basic scheme. Satisfying the two constraints, running distance and running time between two stations, a coasting point is determined by GA with a fitness function consisting of a target running time. Simulation results have shown that multiple coasting points could exist satisfying both of the two constraints. After figuring out consumed energies according to the multiple coasting points, an optimal train speed profile with a coasting point giving the smallest consumed energy has been selected. Simulation blocks for the train performance simulation and GA have been designed with the Simulink.
Image Quality Evaluation for the Railway Abrasion Measurement with a High Resolution
Ahn, Sung-Hyuk ; Kim, Man-Cheol ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 887~894
There is no standard rule for the test of the railway abrasion measurement system composed of the line laser and the camera. This paper is proposed of the method to estimate the performance of the railway abrasion measurement system. The performance estimation is achieved by the quantitative analysis parameters such as MTF, NPS and DQE.
Effect of Shot Peening on the Fatigue of SS400 Weldments
Kim, Jin-Hern ; Goo, Byeong-Choon ; Kim, Hyun-Gyu ; Cheong, Seong-Kyun ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 895~901
Fatigue fracture of the welded joints of bogie frames is one of unsolved problems. To improve the fatigue strength of the welded joints, various techniques have been applied. In this study, we have investigated the effect of shot peening on the fatigue characteristics of SS400 welded specimens. The fatigue lives of four kinds of welded specimens were examined; welded, PWHT, shot peened, and shot peened after PWHT. The results of the fatigue tests show that the fatigue limit of the shot-peened specimens is higher than that of the welded specimens, and the PWHT specimens have a lower fatigue limit than the welded specimens. It was found that shot peening is a very effective method to improve the fatigue strength of SS400 welded joints.
Packet Data Performance Measurement in D-TRS Wireless Network Environment
Song, Byung-Kwen ; Jin, Myung-Suk ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 902~908
TETRA is the standard of Digital Trunked Radio System developed by the ETSI (European Telecommunications Standards Institute). It is currently adopted as Electric Power IT Wireless Backbone Network in Korea, and a national enterprise is going on for versatile utilization of TETRA. To use TETRA wireless network, TETRA modem is very necessary such that performance measurements are very crucial for each TETRA modem by various manufacturers. In this paper, PED (Protocol Evaluation Data) is suggested for PD performance measurement in D-TRS wireless network environment. The performance measurements for different data lengths and transmission intervals are done using TG (Traffic Generator) on Test Bed. The data size is increased by 10 bytes from 10-byte to 400-byte, and it is measured 1,000 times for each transmission interval of 0.5, 1.0, and 1.5 seconds. Based on the transmission time measured, average transmission speed and MER (Message Error Rate) are derived for TETRA Modem performance measurement. Two TMR880i's of EADS are used for TETRA modem, and SwMI (Switching and Management Infrastructure) of EADS is used for switching system in this paper.
A Study on the Optimization of Suspension Characteristics for Improving Running Safety of Railway Vehicle
Lee, Young-Yeob ; Lee, Hi-Sung ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 909~914
A suspension is the most prior apparatus to decide vehicle's running safety and ride comfort, also the suspension stiffness is the most important parameter for the designing of the vehicle. Providing the strong stiffness with the primary suspension in order to improve the running safety with high speed, but it causes a problem with a curve running performance of a railway vehicle. Therefore, many studies deal with the optimal value of suspension stiffness. In this paper, we aim to optimize the suspension system to improve running safety by varying stiffness values of railway vehicle suspension. We have proceeded an analysis by design variables which are position, length, width, stiffness and damping coefficients of primary and secondary suspension to optimize the suspension characteristics. As a result of the optimization, we verified that the derailment coefficients of inside and outside of wheel are decreased in comparison with initial model.
A Study on the Possibility of Place Marketing in Railway
Lee, Won-Hee ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 915~920
Place Marketing is a new strategy for the regional development, using the regional image, facility and history. The purpose of this paper is to search the possibility of place marketing in the area of railway. Already there were some cases to vitalize the close line and out-of-business station. In this context, some ideas to connect the railway with trip, leisure and regional festival are recommended. For the market place, the cooperation with local government is essential.
Evaluation for Risk Priority Number of Railway Power System Facility using Fuzzy Theory
Lee, Yun-Seong ; Byeon, Yoong-Tae ; Kim, Jin-O ; Kim, Hyung-Chul ; Lee, Jun-Kyung ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 921~926
The RPN provides information which includes the risk level and the priority order of maintenance tasks for components. However, if there is no sufficient historical failure data, the historical failure data from other sources can be applied to the target system. And if we use historical data from other sources without any process, there will be concomitant problems according to a discord of each system characteristic, a difference between the present and the date of failure data, etc. In this paper, a new methodology is proposed to model the failure rate as a fuzzy function to resolve these problems. Taking advantage of this result, the RPN can be calculated by using the fuzzy operation. The proposed method is applied to the substation system.
A Study on User's Awareness of Subway Environment Shape Objects in Metropolitan Cities
Choi, Chol-Heyong ; Park, Sun-Woo ; Kim, Chang-Hyun ; Cho, Han-Jin ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 927~935
Environmental shape objects not only play a part as various cultural facilities but also symbolize local unique culture beyond the limit of functional role. Therefore subway environmental shape objects should be approached in terms of public installations and art and should be designed to accommodate and meet the needs of subway users appropriately. In order to find out what subway users think about environment shape objects in subway stations, the factors that can evaluate awareness and preference for environment shape objects and visual image of environment shape objects were examined and analyzed. Positive elements were shown with regard to environment shape objects a lot but it is judged that visual quality of subway environment can be deteriorated if environment shape objects do not harmonize with the characteristics of station environment.
Development of the Risk Assessment Model for Railway Level-Crossing Accidents by Using The ETA and FTA
Kim, Min-Su ; Wang, Jong-Bae ; Park, Chan-Woo ; Cho, Yeon-Ok ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 936~943
In this study, a risk assessment model based on the ETA (Event Tree Analysis) and FTA (Fault Tree Analysis) is developed according to the procedure of hazard analysis and risk assessment in order to estimate the risk quantitatively. The FTA technique is applied to estimate the branch probability (frequency) and the ETA technique is applied to estimate the consequence for each branch path on the ET (Event Tree). A risk assessment model is developed by the combination of those ETA and FTA. In addition, the reliability and the validity of the risk assessment model are verified by comparing the risk estimated through the developed model with the actual equivalent fatality.
Crack Width Calculation Based on Bond Characteristics and Cracking Behavior of Reinforced Concrete Structures
Yang, Jun-Ho ; Kim, Woo ; Lee, Gi-Yeol ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 944~952
This paper presents an analytical model for calculation of crack widths in reinforced concrete structures. The model is mathematically derived from the actual bond stress-slip relationships between the reinforcement and the surrounding concrete, and the relationships summarized in CEB-FIP Model Code 1990 and Eurocode 2 are employed in this study together with the numerical analysis result of a linear slip distribution along the interface at the stabilized cracking stage. With these, the actual strains of the steel and the concrete are integrated respectively along the embedment length between the adjacent cracks so as to obtain the difference in the axial elongation. The model is applied to the test results available
An Estimation Model of the Minimum Required Dwell Time for Urban Railway
Kim, Dong-Hee ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 953~960
In the major operation section of urban railway, there has been occurred habitual delay, and delay propagation and spread to consecutive trains. Therefore, this delay cause the increase of operation time and irregular operation, also the increase of crowd and inconvenience to passengers. The railway operation plan is a promise to passengers and must have reliability. In the case of high frequency urban operation, dwell time have considerable influence on operational headway, so it is very important to efficiently plan and control the dwell time at stations. In this paper, the survey of the research on dwell time for urban railways is presented. The practical estimation model for minimum required dwell time, and the numerical example and validity are proposed.
Parametric Study of the Effects of Train Wind on Turnover Safety
Nam, Seong-Won ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 961~966
When constructing a high-speed railroad, the reduction of the distance between track centers and the width of track bed will save the construction cost. However the shortening the distance between track centers may cause the stability problems due to higher wind pressure. Therefore the extensive technical review and aerodynamical study should be performed to determine the adequate distance between track centers. In this study, the impact that the increase in wind pressure due to the change of aerodynamic phenomena with the change of the distance between track centers may have on two trains passing by each other was predicted, and the stability of train operation was analyzed in order to review the distance between track centers suitable to Honam HSR trains. We conducted the parametric study of the effects of train wind on the running stability.
A Study on Developing the Outcome Management System of Construction and Transportation R&D Project
Jung, Si-Kyo ; Moon, Dae-Seop ; Maeng, Hee-Young ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 967~973
Construction and Transportation R&D budget is increased every year. Therefore, outcome is important issue. Also, we must try for practical use of outcome. And we need strategy for practical use of outcome. This is research for the application of research and development outcome. Specially, this research studies about way for construction standard. And this proposes a institutional improvement. First, it catch a problem point with present condition analysis. Second, It executes a survey and analysis. Finally it presents some policy suggestion. This research solves two problems. This applies to the field of research and development outcome. Another this amend construction standard.
Reliability-Based Optimum Design of High-Speed Railway Steel Bridges Considering Bridge/Rail Longitudinal Analysis and Bridge/Vehicle Dynamic Effect
Lee, Jong-Soon ; Ihm, Yeong-Rok ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 974~982
To improve the effectiveness and economics the bridge design methodology considering the bridge/rail longitudinal analysis and bridge/vehicle dynamic effect suggested in this study. The reliability-based Life-Cycle Costs(LCC) effective optimum design is applied to a 2-main steel girder bridge, 5
(1@50m) for comparison with conventional design, initial cost optimization and equivalent LCC optimization. As a result of the optimum design based on reliability, it may be stated that the design of High-Speed railway bridges considering the bridge/rail longitudinal analysis and bridge/vehicle dynamic effect are more efficient than typical existing bridges and LCC optimization without respect to bridge/rail longitudinal analysis and bridge/vehicle dynamic effect. The result of optimization design considering the interaction, design methodology suggested in this study, is higher than result of initial cost optimization design in initial cost, but that has the advantage than result of initial cost optimization design in expected LCC.
An Analysis of Running Safety for Railway Vehicle Depending on Actual Track Conditions
Kim, Yong-Won ; Lee, Hi-Sung ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 983~988
When the railway vehicle passing through curves & transitions, the running speed must improve by proposing the practical standard about maximum running possibility speed of each section on existing line considering running safety. In this paper, when the railway vehicle passing through curves of actual track conditions (Namsunghyun-Chungdo up & down lines), the effect that has influence on running safety is examined to devise the high speed of vehicle which passing through curves which risk of derailment is high. The running safety analysis is performed that running speed by curve radius improves 5-20% compared with existing speed under actual track conditions. In result of the running safety analysis, in case the speed condition is fewer than 15% compared with existing speed, the derailment coefficient and unloading ratio are within acceptable level. so we could confirm possibility of speed improvement on the whole Namsunghyun-Chungdo up & down lines.
Time-frequency Analysis of Train Vibration Using Order Analysis and Correlation
Choi, Sung-Hoon ; Igusa, Takeru ; Park, Choon-Soo ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 989~995
Short-time Fourier transforms (STFT) are useful for analyzing signals with harmonics that vary with time. If the variation of the harmonics with time is smooth, such as in kinematic vibrations in vehicles, then it is possible to improve the STFT using order spectra and correlation analysis. In this paper, it is shown how correlation analysis can be performed when the speed signal is noisy or unknown and then it is shown how order spectra become simple to compute after this analysis. The results are illustrated by an analysis of axle and car body vibrations in the prototype high-speed train, HSR-350x.
A Study on the Development and Application of the Transport Accounts in Korea
Kim, Han-Young ; Lee, Won-Young ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 996~1010
This paper proposed the framework for the Korean transport accounts which is suitable to Korean situation and can be used for international comparison. The framework is composed of the costs, the revenues and the estimation methodology. This framework is applied to both the Korean road and rail transport, respectively. The result showed that the total cost compared to GDP for the road was higher than the Europe's by 3.23% and that for the rail was lower than the Europe's by 0.67%. Also, the result showed that, in terms of the unit cost, the passenger cost per person-kilometer of road transport was 4.8 times higher than that of rail transport and the freight cost per ton-kilometer of road transport was 2.4 times higher than that of rail transport.
Comparative Analysis on the Railway Construction Criteria with Regard to the Trans-Korea Railway Project and the Railway Modernization of DPRK
Kim, Sang-Gyun ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1011~1017
In pursuit of the Trans-Korea Railway (TKR) project connecting the Korean peninsular by a rail link, it is critical that the two railway systems in ROK and DPRK are comparable in criteria and standards. Yet, there is substantial divergence of the construction criteria between the two sides, which hinders from conducting the TKR project as well as the railway modernization of DPRK. In this regard, study and comparison of the criteria are a prerequisite for mitigating the hinderance. This study investigated the laws and regulations relating to the railway technologies and construction and in particular conducted a comparative analysis of both railway systems with a focus on railway facilities such as track, structures, electric power and signaling. The results of this study will provide a useful information for the improvement of existing lines and the construction of new lines in DPRK.
A Model and Approaches for Smoothing Peaks of Traction Energy in Timetabling
Kim, Kyung-Min ; Oh, Seog-Moon ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1018~1023
This paper describes a reduction in the peaks of traction energy for metro railways in timetabling. We develope a mixed integer programming (MIP) model, which minimizes the number of trains running simultaneously. We suggest two approaches. In the first approach, we use the commercial MIP solver, CPLEX. In the second approach, we propose a heuristic algorithm. We apply both methods to the current daily timetable of the Korea Metropolitan Subway. We determine an optimal solution, which results in an improvement of approximately 25% over the current timetable.
A Study for Control of Thermal Cracking by Heat of Hydration in Subway Concrete Box Structure
Song, Suk-Jun ; Yoo, Sang-Geon ; Park, Ji-Woong ; Kim, Eun-Kyum ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1024~1029
According to increase of massive concrete structures, Thermal crack done by heat of hydration have been increased in a process of the execution. In case of a subway concrete box structure, thickness of structures are almost over 1 meter, and penetrating crack by external restraint takes a bad effect on the durability with a water leakage and deterioration in especially concrete wall. A try of shortening a constructing period often occurs as subway is generally constructed according to a road to decrease a traffic jam. The research proposes executing method by skipping one block as a plan of shortening a constructing period and investigate an influence on thermal cracking control. Additionally, sensitivity analysis is accomplished by changing a height of a concrete wall, and concrete placing and air temperature met with a field condition.
Analyzing the Influence Factors on Efficiency of Railway Transport using DEA and Tobit Model
Lee, Yoon-Mi ; Yoo, Jae-Kyun ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1030~1036
In 1990's, in Europe and some advanced nations, the structural reform of the railroad industry for improving the productive efficiency of the railroad industry and competitive power had been progressed. This paper empirically explores the relationship between railway restructuring and productive efficiency in the railway industry. We use Data Envelopment Analysis (DEA) to construct efficiency scores, and explain these scores, using Tobit regression analysis by using variables reflecting institutional factors and organizational type. Our results suggest that vertical separation, infrastructure and services are separated, and horizontal separation, passenger service and freight service are separated, improve productive efficiency. We also find that market competition has positive effect on the efficiency, but independent management from the government has negative effect, which is in line with economic intuition as well as with expectations on the railway restructuring. As a consequence, increased independence without sufficient competition and adequate regulation may deteriorate incentives for productive efficiency.
Safety Regulation of Railway Embankment using Velocity of Failure Probability
Kim, Hyun-Ki ; Shin, Min-Ho ; Lee, Sung-Hyeok ; Choi, Chan-Yong ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1037~1042
Safety regulation of railway embankment is restricted by safety factor in dry season or rainy season in Korea. Safety factor which is results from the limit equilibrium analysis is varied by various external conditions. And because it has no reflection point, it is very difficult to manage the safety of trains. Safety regulation such like warning sign, reduce speed and train stop is the best choice to reduce the damage of embankments where it is worried about occurrence of disasters. In this study, additional index is proposed to support present safety standards based on unsaturated soil mechanics and reliability analysis. It is velocity of failure probability. It has an apparent reflection point near present safety regulation. It is possible to modify the regulation for safety management and monitoring system of embankments by using this index.
Reliability Analysis for Train Control System by Software Fault Tolerance Techniques
Suh, Seog-Chul ; Lee, Jong-Woo ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1043~1048
PES (Programmable Electronic System) is used by software development for the train control system. PES has been widely used in real world and consists of hardware, firmware and application software. The PES are easily apply to many applications because its implementation has high flexibility. Many safety critical functions are realized through software in safety critical system. Normally, it is difficult to detect failures for PES system because the PES is too sophisticated to identify sources of the failure. So, the reliability analysis is needed by using software fault tolerance techniques. Currently, there are the recovery block, distributed recovery block, N-version programming, N self-checking programming in fault tolerance techniques. In this paper, the models of recovery block and N-version programming in software fault tolerance techniques are suggested by using the Markov model. Also, the reliability in the train control system is analyzed through changing time. The fault occupancy rates of the program, adjustment test and voter are stationary. So, the relation between time and reliability is presented by using Matlab program. In the result of reliability, the reliability of recovery block is more high than N-version programming in case of the same number of substitution block.
A Study on the Rolling Stock Workshop to Analyze the Contribution to the Modern Korean Architecture
Lee, Sang-Haeng ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1049~1058
Korea's Rolling stock workshop were established with the introduction of a railway, and became the center of industrial construction in the modern age of Korea. There still exist a lot of Rolling stock workshop buildings in the Youngsan Rolling stock workshop, the representative case of Korean Rolling stock workshop, and especially the study aims to look into modern architectural properties centered on those well-preserved buildings. Korea's Rolling stock workshop were built considering the proper conditions of location such as the neighboring districts from the port to transport vehicles and materials, the place where railroad lines are centralized, the short returning distance of railroad cars for entry and departure, and had the facility layout according to the order of a working process of vehicles, and the unique structure and the section facade shape with proper functions and sizes according to each purpose. In particular, they actively adopted steel-frame structure and reinforced concrete structure, and came to have the initial characteristics of Korea's modern industrial building which is called the structural transition. Therefore, this study aims to highlight the importance of Rolling stock workshop including the Youngsan Rolling stock workshop as industrial architecture heritage in the modern age of Korea.
The Recovery of Carbon Fiber from Carbon Fiber Reinforced Epoxy Composites Applied to Railway Vehicles
Lee, Suk-Ho ; Kim, Jung-Seok ; Lee, Cheul-Kyu ; Kim, Yong-Ki ; Ju, Chang-Sik ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1059~1066
Recently, the amount of thermosetting plastic wastes has increased with the production of reinforced plastic composites and causes serious environmental problems. The epoxy resins, one of the versatile thermosetting plastics with excellent properties, cannot be melted down and remolded as what is done in the thermoplastic industry. In this research, a series of experiments that decompose epoxy resin and recover carbon fibers from carbon fiber reinforced epoxy composites applied to railway vehicles was performed. We experimentally examined various decomposition processes and compared their decomposition efficiencies and mechanical property of recovered carbon fibers. For the prevention of tangle of recovered carbon fibers, each composites specimen was fixed with a Teflon supporter and no mechanical mixing was applied. Decomposition products were analyzed by scanning electron microscope (SEM), gas chromatography mass spectrometer (GC-MS), and universal testing machine (UTM). Carbon fibers could be completely recovered from decomposition process using nitric acid aqueous solution, liquid-phase thermal cracking and pyrolysis. The tensile strength losses of the recovered carbon fibers were less than 4%.
The Feasibility Studies for Introducing Bimodal Tram System Based on Urban Scale
Eom, Jin-Ki ; Sung, Myoung-Joon ; Kim, Hyun-Woong ; Lee, Jun ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1067~1075
The Bimodal Tram being developed in Korea is a new transit system that provides both benefits of rail and bus systems in terms of accessibility and fixed time schedule. This study accomplished a feasibility study for introducing the Bimodal Tram system by considering the travel demand and existing transit system at a city level based on its population. The feasibility of Bimodal Tram system varies depending on cities with respect to demographic scale, mode shares, and operational distances. The strategies introduced here will help any cities where transport agencies are trying to introduce the Bimodal Tram as a new transit system.
A Study on Modeling of Life Cycle Cost for Magnetic Levitation Train
Lee, Yun-Seong ; Kim, Jin-O ; Kim, Hyung-Chul ; Jang, Dong-Uk ;
Journal of the Korean Society for Railway, volume 12, issue 6, 2009, Pages 1076~1080
An analysis of Life Cycle Cost (LCC) is to evaluate the system through the total cost accounting during the total life cycle. Railway system has problem that abundant capital has to be utilized efficiently because railway system is a combined system such as power supply, machines, electric signals. Especially, Magnetic Levitation Train needs high technique and more study about the Life Cycle cost by using the system being developed currently in Korea. Therefore, the Modeling of Life Cycle Cost for Magnetic Levitation Train is proposed considering the tendency of the studies in other countries.