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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
An Empirical Study for Improving the Aptitude Management of the Railway's Safety-Critical Workers: Focusing on the Way of Stress Management
Shin, Tack-Hyun ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 605~612
The purpose of this article is to empirically suggest the necessity of reconsidering the new aptitude factors such as the ability to withstand work stress, to handle unusual events, and to work independently, in the respect that the environmental change in railway safety-critical worker's job should be flexibly reflected in the current aptitude management system. Besides, several ways of reducing the stress level for the railway safety-critical workers were suggested as well.
The Analysis on Competitiveness of Railroad Transport Focused on Container, Cement, Steel
Kim, Eun-Mi ; Park, Dong-Joo ; Ko, Young-Seung ; Kim, Hyun-Seung ; Park, Hyeong-Jun ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 613~622
The modal spilt of highway has been increased and the one of railway has been decreased from 17.2%(1990) to 6.3%(2006). In this context, it is meaningful to examine the competitiveness of the railroad of Korea. The objective of this study is to analyze the competitiveness of railroad with the highway so that countermeasures improving the competitiveness of railroad could be suggested. For this, firs of all, indicators representing the competitiveness of the railroad transport are determined. The main influencing factors for mode choice include transport time, transport cost and level of service. Three types of commodity, container, cement and steel are the target for the analysis. It was found that the overall competitiveness of railroad transport is weaker compared with highway even for the main freight origin-destination pairs. It means that the freight transport system is focused on road rather than railroad. Therefore, we need to remeasure the competitiveness of railroad transport related to methods for freight railroad competitiveness improvement.
Estimating Line Capacity Considering High-Speeding and Diversification of Trains
Ki, Hyung-Seo ; Park, Dong-Joo ; Choi, Jong-Bin ; Choo, Jun-Sup ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 623~630
The Korean railway system is a mass transit system consisting of a variety of train types such as common trains, high-speed train (KTX) and Metropolitan Express Railway (EMU). Its operation is based on the official timetable and it provides us with safe, accurate, quick and comfortable service. The objective of this study is to propose and prove more practical method for estimating line capacity by considering high-speeding and diversification of trains. In particular, the focus of this study is to reduce the discrepancy between the result of the theoretical line capacity estimation and the real line capacity of the operating agency of the Korean railway. In order to achieve the object, this study introduces a new railway capacity notion by considering TPS of line alignment, the operation type, train control and signaling system, etc. Through a practical schedule diagram exemplification, the result of the proposed method is verified as well.
The Effects of the Wave Propagation Path of Ground Vibration Induced by the Subway Train on the Reduction of Vibration Level
Shin, Han-Chul ; Cho, Sun-Kyu ; Yang, Shin-Chu ; Lee, Jong-Min ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 631~640
In this paper, Numerical analysis was conducted to study on the reduction of ground vibration level induced by subway train. The analytical results indicated that the soil properties were the predominant factor affecting the ground vibration when the tunnel was located in the soil layer. On the other hand, the rock properties were the predominant one when the tunnel was located in the rock layer. The effects of the angle between the vertical line of vibration source and the receive point on the reduction of vibration level were also evaluated. There were little difference in the reduction of vibration level when the receive point was located within
. The vibration level, however, rapidly decreased when the angle between the two points was larger than
Bonding Characteristics of Basalt Fiber Sheet as Strengthening Material for Railway Concrete Structures
Park, Cheol-Woo ; Sim, Jong-Sung ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 641~648
Concrete structures become more common in railway systems with an advancement of high speed train technologies. As the service life of concrete structures increases, structural strengthening for concrete structures may be necessary. There are several typical strengthening techniques using steel plate and fiber reinforced polymer (FRP) materials, which have their own inherent shortcomings. In order to enhance greater durability and resistance to fire and other environmental attacks, basalt fiber material attracts engineer's attention due to its characteristics. This study investigates bonding performance of basalt fiber sheet as a structural strengthening material. Experimental variables include bond width, length and number of layer. From the bonding tests, there were three different types of bonding failure modes: debonding, rupture and rip-off. Among the variables, bond width indicated more significant effect on bonding characteristics. In addition the bond length did not contribute to bond strength in proportion to the bond length. Hence this study evaluated effective bond length and effective bond strength. The effective bond strength was compared to those suggested by other researches which used different types of FRP strengthening materials such as carbon FRP.
Survey on the Adoptability of IT and Smart Sensor Technologies into the Next-Generation High-Speed Train
Chang, Duk-Jin ; Kang, Song-Hee ; Song, Dahl-Ho ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 649~655
To join the leading four countries in high speed railway technology, the next generation high speed railway technology development project is undergoing. And, applying the IT for the safety and convenience of a passenger and an attendant is one of the research topics of the project. From the 24 derived candidate IT applications, the seven applications, such as information on an individual LCD monitor, an emergency or reminder notification, an Internet connection, remote communication with an attendant, air quality monitoring, extraordinary noise detection, and detection of an emergency in the lavatory, were selected to be implemented on the next generation train. In this paper, we presented the survey that was performed to make the selection process to be objective. Additional findings, such as what other services a passenger wishes to be provided, what activities passengers prefer to do based on duration of the trip, and things that make a passenger discomfort, were summarized.
Estimating Probability of Mode Choice at Regional Level by Considering Spatial Association of Departure Place
Eom, Jin-Ki ; Park, Man-Sik ; Heo, Tae-Young ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 656~662
In general, the analysis of travelers' mode choice behavior is accomplished by developing the utility functions which reflect individual's preference of mode choice according to their demographic and travel characteristics. In this paper, we propose a methodology that takes the spatial effects of individuals' departure locations into account in the mode choice model. The statistical models considered here are spatial logistic regression model and conditional autoregressive model taking a spatial association parameter into account. We employed the Bayesian approach in order to obtain more reliable parameter estimates. The proposed methodology allows us to estimate mode shares by departure places even though the survey does not cover all areas.
Development of a Pulley-type Tensioning Device
Lee, Ki-Won ; Cho, Yong-Hyeon ; Park, Young ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 663~669
In the electrical railway, the increase of tensions in an overhead contact lines is essential to speed-up of train, because current collection quality largely depends on the ratio of a wave propagation speed to a train speed. For Kyungbu high-speed line, a pulley-type tensioning device is required to have a tension variation of maximum 3%. Therefore we developed a pulley-type tensioning device in order to meet tension variation requirement of the high-speed tensioning device. To verify the performance of the developed device, a performance test, overload test and failure test were carried out according to the factory test procedure of the Kyung-Bu High-speed line. Furthermore, we also performed reliability performance through not only a fatigue test in a factory, but also on-line verification test in Chungbuk line for over 1 year. These tests verified that the tensioning device had applicability to a main line.
A Study on Maximum Speed Test for On-board Signalling Equipment in HEMU-400x
Shin, Duc-Ko ; Lee, Jae-Ho ; Lee, Kang-Mi ; Kim, Yong-Kyu ; Park, Choon-Soo ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 670~677
This paper is a study of testing on-board signalling equipment in advanced high speed rail at the maximum speed of 400km/h. The on-board signalling equipment in advanced high speed rail provides operating information to the driver when operating at ATC, ATS, and ATP sections, and maintains safety from driver oversight, signalling equipment malfunction, natural disasters and so on. Since the testing train performance of advanced high speed rail at 400km/h must include the function test of on-board signalling equipment, this thesis focuses on the function test of on-board signalling equipment and analyze the necessity of the test at the maximum speed. Finally, it is suggested to change some infrastructure and to use specific test methods to test the train performance at the maximum speed in high speed line ATC section.
Analysis of Occurrence Tendency of Rail Force According to Running the Hanvit 200 Train on Transition Curve Track
Park, Yong-Gul ; Choi, Sung-Yong ; Kim, Youn-Tae ; Choi, Jung-Youl ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 678~686
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. Therefore, in this study, the dynamic rail force of the tilting (Hanvit 200), high-speed (KTX) and general (Mugunghwa) vehicle caused by driving in transition curve track was measured. And, it compared the tilting response with the other by using the measured rail force data in transition curve track, and then evaluated probability the range of load fluctuation for the variable dynamic vertical and lateral wheel load. As a result, a range of rail force by occurred a change of cant from the high-speed and general vehicle which had fixed bogie structure was distributed throughout small deviation. Otherwise, in case of the tilting train which was consisted of the pendulum bogie structure was distributed wide range about large deviation by changed of cant.
An Algorithm to Analyze Rail Potential Rise in DC Traction Power Supply System
Chung, Sang-Gi ; Kim, Hyung-Chul ; Jung, Ho-Sung ; Kwon, Sam-Young ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 687~693
An algorithm and a computer software are developed for the analysis of rail potential rise. The algorithm is intended to be integrated with the traction power system simulation program. In the algorithm, rail potentials are obtained by two step process. First the injection currents to the negative rail are obtained from load-flow study. In the next step, a network consisting of negative rail and the injection currents are constructed. Leakage resistance to ground are added to the network. And the network is analyzed for rail potentials. A software is developed to verify the validity of the algorithm. The result of the software is compared with the Simulink/SymPower circuit analysis result. The differences between the two results are with the acceptable range. The advantage of this algorithm is that it can be integrated with the existing traction power supply simulation program easily, which usually ignores negative rail's leakage resistance.
A Synchronous-Reference-Frame-Based Single-Phase UPQC for AC Electrified Railway Systems
Park, Han-Eol ; Kang, Ok-Ku ; Jang, Woo-Jin ; Song, Hwa-Chang ; Song, Joong-Ho ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 694~699
This paper presents a synchronous-reference-frame-based control of single-phase UPQC(Unified Power Quality Conditioner) to improve power quality in ac electrified railway systems. The proposed synchronous-reference-frame-based UPQC can compensate the voltage distortion, the voltage sag, the harmonic currents, and the reactive power instantaneously. The simulation results show that the UPQC can compensate the harmonic supply voltages, the voltage sag, the harmonic load currents, and the reactive power in electrified railway systems. Validity and effectiveness of the proposed UPQC control method based on the synchronous-reference-frame is illustrated through the simulation results.
A Methodology Study for Estimating the Benefits of Tilting Train Deployment
Lee, Jin-Sun ; Kim, Kyoung-Tae ; Eom, Jin-Ki ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 700~706
Unlike high-speed KTX trains and dual track railways, most single-track railways are not popular among passengers because of long travel hours. As a solution to the problem, tilting trains will be deployed along the conventional line. Tilting train has a mechanism that enables increased speed on regular and curved railway tracks. As a train rounds a curve at speed, objects inside the train experience centrifugal force. This can cause packages to slide about or seated passengers to feel squashed by the outboard armrest due to its centripetal force, and standing passengers to lose their balance. Tilting trains possess a top speed of up to 180 km per hour as opposed to the previous 140 km per hour, so allow the train to pass curve at higher speed without affecting passenger comfort. This paper describes the methodology study to estimate the benefits, especially on the extra benefits in case of tilting actuation.
A Study of the User's Evaluation on the Korea-China Railferry System
Cho, Chan-Hyouk ; Chung, Byung-Hyun ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 707~713
Planning railferry system in Korea-China trade routes, the overall evaluation and customer response are coming under spotlight in a preference and feasibility perspective. Persistent Railferry issue has been an area of study for the last decade. But until now, a surveyor or the evaluation from the actual users were exceptionally rate. Consequently, there is a need for a more detailed study into the practical issues such as customer response and railferry demand etc. Using a questionnaire survey from actual users, this paper examines the underlying evaluation on the Railferry system both in terms of demand and preference. The research questions were analyzed on data collected from almost 150 users in Korea. A range of arguments and expected problems were summarized. The results in general find a negative relationship between railferry preference and respondents' work experience. Findings in the reasons respondents are objecting the new railferry system, the suitable cargo type of railferry, and the possible barriers to introduce the system are discussed. Nonetheless further researches into railferry system as a possible alternative for Korea-China-Japan corridor should be followed in the near future.
An Experimental Study of Smoke Reduction System using Vacuum
Ham, Sung-Hoon ; Kwon, Young-Woong ; Oh, Se-Hoon ; Park, Sung-Cheon ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 714~718
Over the past years, many research works have been carried out to investigate the factors which govern the performance of diesel engine. The air pollutant emission from the diesel engine is still a significant environmental concern in many countries. In the present study, new system of smoke reduction of diesel engine is proposed. This new system is using vacuum equipment and filter included moisture for capture smoke. To verificate new system experiments were performed at diesel vehicle. As a result it is founded that smoke is decreased.
Finite Element Analysis and Validation for Mode I Interlaminar Fracture Behavior of Woven Fabric Composite for a Train Carbody Using CZM(Cohesive Zone Model)
Kim, Seung-Chul ; Kim, Jung-Seol ; Yoon, Hyuk-Jin ; Seo, Seung-Il ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 719~724
In this study, DCB(double cantilever beam) specimens of woven fabric carbon/epoxy and glass/epoxy were manufactured and mode I fracture toughness of specimen was measured according to ASTM 5528-01. And FE analysis was conducted in the same condition and evaluated the behavior of delamination analytically. Mode I fracture toughness measured by test was
in the case carbon/epoxy and that of glass/epoxy was
. FE analysis was conducted using cohesive elements for adhesive layer and applied measured fracture toughness. To verify the result of analysis, the reaction force measured at the end of specimen and that calculated by Timoshenko beam theory were compared. The numerical results show good agreements with the measured one.
Fatigue of SS490A and SS400 Corroded Specimens
Goo, Byeong-Choon ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 725~731
For structural design and diagnosis, quantitative relationship between corrosive degradation and variation of mechanical properties such as tensile strength and fatigue strength is needed. But it is difficult to find experimental data associated with corrosive degradation of structural structures in the literature. In this study, first of all I established the atmospheric corrosion test procedure. And using specimens of SM490A and SS400 on the atmospheric corrosion test bed, I carried out tensile and fatigue tests at regular intervals. And we studied the effect of post-weld heat treatment on the tensile and fatigue behaviour. It is found fatigue strength decreases as the atmospheric corrosion period increases.
A Real-scale Wind Tunnel Testing on a Pantograph for High-speed Train to Assess the Aerodynamic Characteristics
Kwon, Hyeok-Bin ; Cho, Young-Hyeon ; Lee, Ki-Won ; Kim, Ki-Nam ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 732~737
Wind tunnel testing on the real-scale pantograph for high-speed train has been conducted to investigate the aerodynamic characteristic of the pantograph at high-speed. The mid-scale subsonic wind tunnel of Korea Airforce Acamedy with 3.5m width, 2.45m height, and 8.8m length test section has been employed. The test model has been supported above 50cm height from the bottom of test section using vertical strut to eliminate the boundary layer generated from the bottom of the test section. The height of the pantograph has been varied in three cases, in both of the normal running and reverse running modes. The resultant lift forces of the pantograph to catenary system in all the cases have been measured and the relation between the test conditions and the lift forces have been extensively analyzed.
Development of Safety Equipment for Protection of Trackside Personnel Maintaining Using Radio Frequency Equipment
Hwang, Jong-Gyu ; Jo, Hyun-Jeong ; Yoon, Yong-Ki ; Kim, Yong-Kyu ; Jang, Yeong-Jun ; Ko, Yeong-Hwoang ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 738~743
Personnel maintaining or repairing the railway tracks or signaling device around tracks may experience the sensory disorder when they do routine works for many hours and they may not recognize the leading to train accidents. In order to prevent such train accidents that may occur because railway track workers are unable to recognize the approaching train, a safety-equipment is developed to make the approaching train send signals. We developed the new alarm equipment for protection of trackside maintenance workers using radio signals.
A Study on the Feasibility of Evaluating the Complexity of KTX Driving Tasks
Park, Jin-Kyun ; Jung, Won-Dea ; Jang, Seung-Cheol ; Ko, Jong-Hyun ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 744~750
According to the result of related studies, the degradation of human performance has been revealed as one of the most significant causes resulting in the safety of any human-involved system. This means that preventing the occurrence of accidents/incidents through avoiding the degradation of human performance is prerequisite for their successive operation. To this end, it is necessary to develop a plausible tool to evaluate the complexity of a task, which has been known as one of the decisive factors affecting the human performance. For this reason, in this paper, the complexity of tasks to be conducted by KTX drivers was quantified by TACOM measure that is enable to quantify the complexity of proceduralized tasks being used in nuclear power plants. After that, TACOM scores about the tasks of KTX drivers were compared with NASA-TLX scores that are responsible for the level of a subjective workload to be felt by KTX drivers.
A Study on the Evaluations and Issues of Rail Container Transport in Korea Railway
Woo, Jung-Wouk ; An, Joon-Yong ; Kim, Hyoung-Gi ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 751~760
The purpose of this study is to search how to improvement mathods of rail freight by understanding the problems and the evasion reasons in coping with various case of logistics environment and to enhance competitiveness of rail freight. So we examined improvement of in the productivity in the rail container possibility for Modal shift in Korea railway, we have done a survey among the shiffer and multimodal transport operators in Korea. Data were analyzed using quantitiative mathod.
The Effects of the Service Orientation on Job Satisfaction and Customer Orientation of the Urban Railway-operating Company
Lee, Hyun-Ju ; Kook, Kwang-Ho ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 761~771
This paper performed an empirical study through the survey to investigate the effects of the service orientation of the urban railway-operating company on employees' job satisfaction and customer orientation. For this, the surveyed data was analyzed through factor analysis, reliability analysis, and regression analysis. The difference between railway-operating companies was analyzed by the t-test and the differences between workers in different fields were analyzed by the ANOVA test. The results show that 1) human resource management, employee empowerment, service leadership, and service system are positively related to employees' job satisfaction in the decreasing order, 2) the service system, human resource management, and service leadership are positively related to customer orientation, but employee empowerment is negatively related to customer orientation, 3) the workers of the urban railway-operating company A and B show significant differences in job satisfaction and customer orientation, and 4) the job satisfaction and the customer orientation of the rolling stock maintenance workers was the highest and that of service workers in station was the lowest.
Design and Control Strategy of Fuel Cell Hybrid Power System for Light Electric Railway Vehicles
Kim, Young-Ryul ; Park, Young-Won ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 772~777
The development of fuel cell hybrid power system, as a next generation power system to promote clean energy which will mitigate the continued global warming, has demonstratd a significant progress in passenger vehicle applications. Also, in case of railway vehicles in non-electrified railway lines, the adoption of fuel cell hybrid power system is being studied among well-known manufacturers. This paper introduces both the configuration and the control strategy of fuel cell hybrid power system to apply to a light electronic railway vehicle having a repeated driving pattern of acceleration, coasting and deceleration. The simulation results demonstrate the viability of the proposed power system design and its control strategy.
A Historical Review of Socio-economic Changes of Railroad
Lee, Yong-Sang ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 778~787
This paper illustrates some examples of socio-economic changes brought about by railroads in Korea. The Korean railroad network has been running for 110 years since it started operation in 1899. The opening of railroad system in Korea has had a huge influence on its society, not only transportation but also in the development of infrastructure and formation of new cities, such as Daejeon Metropolitan City, which were built along with the rail network. This paper will examine some examples of the influence that railroads have had on Korean society: the changes of transport route from road to railroad, the emergence of new cities, industries and culture. Also, this paper will look over the various functions of railroads in Korea, and then it compares with those of foreign countries. It gives us chance to examine a specificity as well as universality in the function of railroads.
Investigation of Soil Pollution Status for Railroad Depot
Oa, Seong-Wook ; Lee, Tae-Gyu ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 788~792
Railroad is well known for eco-friendly transportation system. But, for past few decades, there might be happened many contamination acts in railway facility sites. Industrial and municipal solid wastes produced to maintain and fix trains were dumped to underground of railroad depot area. To develop and reconstruct this area, we should remediate the contaminated soil and ground water. This study was conducted to evaluate the soil pollution status of railroad depot and propose the optimum remediation processes. Our investigation showed that main pollutants sources were TPH and some heavy metals from the dump site. The surveying results for the soil under rail track and crossing nose areas showed TPH contamination from crossing nose area causing lubricant agent. It could be use and rehabilitate the railroad facility areas to an intended purpose with an application of well designed in-situ and ex-situ remediation processes.
A Study on the Application of the Six Sigma Techniques to Railway Safety
Song, Bo-Young ; Kim, Man-Ung ; Moon, Dae-Seop ; Lee, Dong-Hun ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 793~799
Using transportations like railway, aviations and roads have been increasing continuously. Traffic accidents have been increasing as well. To prevent or lessen these accidents become a big issue to solve. Therefore, more enforced safety levels are being required to meet. In railway field, continuous efforts of railway safety are being executed to prevent traffic accidents. In present, railway accidents have been decreasing since subway accident happened in Daegu Subway in 2003. However, safety levels in railway field have not yet achieved as much as in advanced countries. Basic concept for enforced safety level in railway system is to prevent or minimize accidents by managing systems like related facilities, management method, organization, education. This is the same concept to minimize error rate in six sigma theory. In this paper, we are to apply six sigma techniques used in manufacturing industry to railway safety and go through ways to make more efficient railway safety system.
Development of the Track System for a LIM Type Maglev
Yeo, In-Ho ; Kim, Dong-Seok ; Jang, Seung-Yup ; Hwang, Sung-Ho ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 800~805
This paper proposes the track system with twin block sleeper for a LIM type maglev railroad. Because a LIM type maglev railroad is expected to be constructed in inner city, social costs can be required under construction. Accordingly, superstructure using precast plate was adopted and twin block sleeper which can be constructed together with precast plate was developed to reduce the construction period. To examine the structural safety of the proposed track system with twin block sleeper, the finite element analyses and the laboratory experiments were performed. Also, the workability of the proposed track system was investigated through the construction simulation test and construction experience in test bed.
An Experimental Study to Develop the Perforated Panel System for Noise Chamber
Lee, Young-Sup ; Lee, Dong-Hoon ; Chung, Kwang-Seop ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 806~810
The air conditioner system that is used in large structure, such as hospital, hotel, railway platform and train generate a high level noise generally. A chamber with sound absorbing materials, such as glass wool and polyurethane foam, are installed in this system to reduce the noise. However, these chambers cause environmental problems owing to the sound absorbing materials recently. Therefore, we develop noise chamber a built-in perforated panel resonance system as eco-friendly chamber to solve this problems. This noise chambers show the same noise reduction performance as the current chambers in the range above 500Hz. But, it reduces the noise up to 8dB(A) comparison to the current chambers in the range 200Hz~400Hz.
An Experimental Study on the Prediction of Progressive Cracking around Tunnel Fallout
Lee, Jun-S. ; SaGong, Myung ; Ahn, Sung-Kwon ; Yoo, Sang-Geon ; Song, Suk-Jun ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 811~818
An estimation method of the fallout volume of a tunnel under construction is proposed based on an empirical method called bulking factor. For this, the main causes of the tunnel fallout are investigated and the scale of the fallout which is not accessible is considered. The calculated height of the fallout area is compared with borehole core data and the accuracy and efficiency of the proposed method is demonstrated. Another experimental approach on the detection of a progressive cracking around the tunnel fallout is provided based on an acoustic emission method. From the field tests near the tunnel fallout, it is shown that additional progressive cracking of the reinforced area is not foreseen and the effectiveness of the reinforcement is proven.
Development of Standard Operation System of Emergency Restoration for Railway Accidents
Park, Yong-Gul ; Sung, Deok-Yong ; Choi, Sung-Yong ; Suh, Sang-Kyo ;
Journal of the Korean Society for Railway, volume 12, issue 5, 2009, Pages 819~828
This paper suggests to standardize railway accident restoration types as the code and standard operation system for efficient railway accident management. First of all, the damage types of have been carefully analyzed and reclassified. This study suggested the combination of 3 distinct code factors: restoration class, restoration object, and restoration location to standardize them. In addition, this study suggested procedures to make the standard operation system of emergency restoration, defined the worst case of emergency restoration and the important events. Therefore, the standard operation system of emergency restoration is developed. It shall play a major role as the database system for railway accident management, minimum of damage and rapid control of accident.