• Journal of the Korea Safety Management & Science
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• v.9 no.4
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• pp.49-56
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• 2007

It is known that human factors account for 80 percent of all railway accidents. To reduce human errors must be the most efficient shortcut to railway safety. For public transportation employees like railway, the more delicate safety management should be executed in individual level. However, there are rarely efforts to improve safety performance of workers who are the subject operating the railway system. This paper develops a hierarchy model to evaluate the human safety performance in railway industry. To evaluate the model, AHP (Analytic Hierarchy Process) methodology is adopted. The hierarchy model is composed of four levels which are objective, two criteria, specific factors of criteria, and rating scales. In addition, since employees for evaluation are over 10, the pairwise comparisons for rating scales are carried out by the absolute measurement. We explore the applicability of AHP to the performance evaluation of railway safety workers by an example and also investigate the changes of alternatives that are railway employees according to the changes of human characteristic which is one of criteria.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.750-761
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• 2008

The social and economical value assessment of railway facilities implies unaccountable values such as: reduction of travel time, reduction of car accident, reduction of air pollution. However, the value of railway facilities has been evaluated as the transportation and management results. The investment and management results of railway need to be considered objectively. Therefore, this study established the economical value assessment method of railway facilities composed of 10 items of economical value through the existing a preliminary assessment investigation, a manual of railway investment assessment, paper study. In addition, this study proposed the strategy for the value assessment of railway facilities before and after.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1-9
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• 2008

A wide metropolitan railway and a metropolitan railway in metropolitan area are transportation systems to cope with possible large demand and are under construction continually. A wide metropolitan railway and a metropolitan railway in metropolitan area are running with low speed because it is difficult to improve train speed according to short distances between stations and topography. There is a few study on improving commercial speed on the existing wide metropolitan railway and metropolitan railway in metropolitan area, but there is no study on a new wide metropolitan railway. This study present speed-up scheme of the Sosa-Wonsi line by enlarging the curve radius, reducing the horizontal steep gradient, reducing the stopping time, speeding up at underground section, and installing the PSD, etc. This scheme is evaluated using the simulation technique.

• Journal of the Korean Society for Railway
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• v.17 no.6
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• pp.457-465
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• 2014

This study proposes a policy for urban railway travel demand management system in order to decrease the load factor of the Seoul metro Circle line, particularly for the segment between Sadang and Samsung stations, through analyzing the transit smart card data. We propose mixed train operations of the existing Circle line and a line that goes toward Samsung station in order to transport passengers that have two distinct groups: those with the destination of Samsung station and those with destinations after Samsung station. The introduction of a mixed train operation that encourages passengers passing through Samsung station to take a Circle line train will decrease the congested load factor by 11.3% during the morning peak hours using the mixed train operation of the Circle and Samsung lines. This policy could be an effective method to decrease the load factor and improve the comfort of rail passengers without extra investment in the railway facilities.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.7
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• pp.535-540
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• 2016

The braking device in railway vehicles decelerates or stops the train by dissipating the thermal energy converted from kinetic energy into the air. Therefore, the brake system is crucial for safety. In this paper, we performed a study on an electromechanical brake actuator using an electrical motor as an alternative to pneumatic air cylinders to reduce the idle running time in braking, which subsequently increases braking distance, and to ensure reliable response characteristics. Especially, to analyze the response characteristics of the electromechanical brake actuator, we measure the delay time, response time and power consumption compared to the air cylinder. It is confirmed that the electromechanical brake actuator can reduce reaction time by 0.1 seconds (Braking Action) and 0.46 seconds (Brake Release) compared to the air cylinder.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.1-6
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• 2013

In this study, the natural frequency and damping ratio of a four-harness satin woven glass/epoxy composite material are evaluated by means of modal tests and a finite element analysis. To achieve this goal, glass/epoxy beam specimens with different lengths and thicknesses were manufactured via autoclave curing. In the test, the maximum damping ratio was found to occur at the lowest test frequency. As the test frequency increased, the damping ratio decreased exponentially to a critical value. After that value, the damping ratio increased gradually to the maximum test frequency.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.7
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• pp.619-625
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• 2015

There is a large interest to find reliable and automatic methods for crack detection and quantification in the railway bogie frame. The non-destructive inspection of railway bogie frame has been performed by ultrasonic and magnetic particle testing in general inspection. The magnetic particle method has been utilized in the defect inspection of the bogie frame but the grinding process is required before inspection and the dust is developed resulting from the processing. The objective of this paper is to apply the inspection method of bogie frame using infra-red thermography. The infra-red thermography system using the excitation of eddy current was performed for the defect evaluation of weld specimen inserted artificial defects. The result shows that the infra-red thermography method can detect the surface and inner defects in weld specimen for bogie frame.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.536-543
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• 2011

The previous researches on railway sector have focused on the total greenhouse gas(GHG) emission through national approaches. The aim of this study was to calculate GHG emission at a local government level to measure each city's GHG intensity on rail transportation. This study followed 'the guidelines for local government greenhouse gas inventory(issued by Korea Environment Corporation)' including VKT(Vehicle kilometers Travelled) methodology for railway inventory at a metropolitan area. As a result, the gyeongsangbuk-do emitted the highest GHG emissions at a local government level, followed by chungcheongnam-do and chungcheongbuk-do in 2006. Among several cities, Gimcheon-city emitted the highest GHG at basic government level in 2006. In future, the calculation of GHG emissions at local government level can be applied to establish various policies for GHG reduction.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.477-483
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• 2011

Climate changes and environmental pollution problems are continuing every year. In Korea, the carbon dioxide(CO2) emissions by the transport sector reached around 20% of pollution. Many countries are enforcing the pollution-control policy. Korean government has introduced the modal shift grants as well as in other countries. In case of nation's transportation plan, the policy basis of green distribution is emphasized. However, the shipper and logistics company have low interests in the modal shift as the massive transportation system. The purpose of this paper is that I studied the policy alternatives for the modal shift of foreign railways., And also I studied the difficult problems at altering the railway freight from domestic road freight and I suggested the alternatives of modal shift to solve those problems.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.915-923
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• 2011

Our country is promoting the introduction of new means of transportation due to insufficient supply according to the existing demand of road traffic. Among them, manless light railroad transit is settled down as the most definite alternative. However, new traffic systems such as manless light railroad have certain difference between characteristics of hardware and software and subway system. Therefore, there will be many differences compared to the existing contingency system when accidents occur. Railway management organization has to establish railway contingency plan and acquire permission from the minister of the Ministry of Land, Transport, and Maritime Affairs. However, as commercial transportation is available, a new traffic system also should establish contingency plan. Therefore, the establishment of systematic contingency plan is suggested in order to analyze characteristics of manless light railroad in the beginning of introduction and to make contingency response available.