• Proceedings of the KSR Conference
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• 2007.11a
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• pp.650-657
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• 2007

Since the railroad accidents due to the human error occupy considerable proportion among the railroad accidents, it is necessary to study the propriety of the physical examination system for the railroad workers. Our government is promoting some systematic supplementation for railroad safety on the basis of the Railroad Safety Act. In this paper, we perform a comparative analysis of domestic and foreign physical examination systems for railroad workers. We also compare the physical examination system for public officials with that for railroad workers. Then we consult expert opinions of the Korean Society of Occupational and Environmental Medicine. Through the comparative analysis, we provide useful information that is needed to amend the physical examination system.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.267-273
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• 2011

Since 'The Act on Private Investment of The Infrastructure' was established in 1994, private investment as well as government's investment in transport infrastructure has been active. However investment in transport infrastructure has more risks than others' due to uncertainty both in traffic volume and in construction cost. In the current appraisal procedure of deciding transportation infrastructure investment, instead of risk management, the sensitivity analysis considering only the changes of benefit, cost and social discount rate which are main factor affecting economic feasibility is carried out. Therefore the uncertainty of various factors affecting demand, cost and benefit are not considered in feasibility study. In this study the problems in current investment appraisal system were reviewed. Using Delphi technique the major factors which have high uncertainty in feasibility study were surveyed and then improvement plan was suggested in the respective of classic 4 step demand forecasting method. The range estimation technique was also mentioned to deal with the uncertainty of the future.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.71-80
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• 2015

During normal subway rush hours, a train-driver is in charge of more than 3,000 people on a daily basis. When an emergency event occurs, millions of people and their property come to depend only on the train-driver's ability. After the Daegu subway fire disaster in February 2003, the Railway Safety Act was enacted in October 2004 and the 'Train Drivers' Licensing System' was introduced by the National Railroad Administration in July 2006 to secure and improve protection. This study was conducted to investigate and evaluate the effects of the Train Drivers' Licensing System since the Licensing System was first introduced eight years ago. In addition, the analysis will suggest better policies for the effectiveness of the 'Train Drivers' Licensing System'.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.458-464
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• 2008

The objective of this paper is to seek an alternative to figure out appropriate ways since difficulties lie in the introduction of LRT system to be operated by governments and self-governing local governments in the country. This situation can act as a main cause of breakdown in domestic railway industry by deepening of outflow of national wealth and technological dependency. Policy makers are required to get awareness of justification and necessity of Project management such as project strategy, goals, operating budgets, risks, investment revenue prior to preparing the outline of the introduction of LRT system shall consider securing budget in light of performance, reliability, and safety withe the help of system engineering activities during the entire project cycle such as design, construction, quality management, and commissioning before mapping out the basic plans for LRT project. In view of the current domestic conditions, the first time within the country, Seoulmetro is training professional as trust education of specialist training about LRT system, SE and PM education. This study leads to participating in PM/SE business by human power who finished from education of domestic specialist for LRT introduction corporation and businesses, it is published for introduction of specialist education and business revitalization.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.441-445
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• 2008

LRT is eco-friendly transportation system and can be constructed at less than half cost of subway. Therefore many local governments have planned to construct a various type of LRT and some of them were already under construction. In Para. 2 of Art. 22 of the "Enforcement Decree of Urban Railroad Act" - safety standard of urban railroad vehicle, It can't be operated if "structures and devices" don't come up to standard required to safety operation. Constructor or operator should give an order or operate according to safety standard in Art. 3 of the Safety Standard of Urban Railroad Vehicle. Safety Standard of Urban Railroad Vehicle of 2000 was reformed once to tighten fire safety standard in 2004 after subway accident in Daegue. It was entirely made for medium and large-sized electric motor car. LRT, based on driverless operation and articulated bogie, has different safety standard in signalling devices and the axle load. etc. So many institutes related LRT have required to amend. In this paper, we described features of LRT vehicle and necessity of amendment and discussed how it should be amended.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1364-1371
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• 2011

Advanced EMU completed a production of test train, composed of 6 cars, after 5 years of development process, and it is currently under the process of integrated test and evaluation to inspect performance of car system, efficiency of transport, safety, punctuality, energy efficiency in accordance with urban railways act at Daebul test line. Advanced EMU was produced under consideration of transportation capacity, maintainability, reliability, energy saving, convenience of passengers, and traffic-vulnerables, so it has an epochal difference from former EMU system. And advanced EMU assures operation management from manager's perspective and efficiency of maintenance for practicalization of car and individual equipment. This paper introduces each major equipment of advanced EMU which is based on many years of experience of management and maintenance.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1031-1035
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• 2007

When vehicles running, vertical force and lateral force act except load of vehicles to rail and wheel. This force happens by complex motion at running. If mark vertical force by P and lateral force by Q, derailment coefficient displays Q/P, most important indicator pointer of running safety judgment. If Q is grown than P from derailment coefficient, than arrived to derailment because wheel climb or jumps over rail. Wheel climb derailment among kind of derailment is when attack angle is +, wheel and rail strike and flange rides to rail. This derailment occurs much in curved line and occurs in low speed. In this study, occurred when running at low speed on curved line, analyze cause of derailment and presented the countermeasure plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.694-702
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• 2017

In the case of an elevated railway station, structure borne noise and vibration due to structural limitations allow the load and vibration from railway vehicles to be directly transmitted to the station structure, resulting in an increase in the number of civil complaints from customers and staff of the station. The floating slab track system, which is well known as one of the solutions for reducing the noise and vibration from elevated railway stations, usually contains rubber mounts or rubber pads under the railway slab which act as a damper. These types of device have the disadvantage that is difficult to predetermine the exact stiffness and damping ratio under the nonlinear loads resulting from train services. In this study, an isolator with a friction type of wedge is introduced, which can be applied to floating slab track systems and to be designed with precisely the required stiffness. Furthermore, a comparative analysis of the stiffness between the designed and experimental values is carried out, while the damping ratio, which is closely related to the friction wedge blocks, is deduced according to the train load condition. The performance tests of the isolator were conducted in accordance with the DIN 45673-7 standard which includes both static and dynamic load tests. The load conditions for the performance tests are designed to conform to the DIN standard related to the weight of the train and rail track, in order to perform vertical and horizontal load tests, so as to ensure the secure structural safety of the railway. Also, by checking the change aspect of the friction coefficients of the friction elements according to the loading rate, the vibration reduction performance of the friction type isolator with variable loading rate conditions is examined.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.18-30
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• 2023

Purpose: This study is to contribute to the development of monitoring technology through the increase of confidence in construction monitoring by deriving the analysis of construction monitoring cost and improvement measures of railway tunnel construction in Seoul. Method: It presents the status on design and contract of construction monitoring cost, status on application construction monitoring cost and its analysis, analysis on safety management cost and quality management cost, expansion of application of the price calculation standard for monitoring management services to improve this, and monitoring for direct order of ordering organization. Results: If the monitoring management service that was meanwhile ordered as included in the construction work is performed by the directly selected company of ordering organization through the preliminary screening for bidding qualification, then the improvement of monitoring quality and the accurate monitoring data can be secured. Conclusion: For the price calculation standard for monitoring management service, the application of actual cost addition method under the Engineering Promotion Act and the calculation standard of monitoring management cost for standard estimation for ground survey should be extended through the direct order of ordering organization, not the method to be included in the net construction cost where it is performed by a subcontractor via contractor.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.113-122
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• 2018

A hydraulic breaker is an attachment of an excavator, and it crushes stones. Recently, research to reduce the impact and noise of breakers are ongoing. In this paper, a method to improve the upper, lower, and side dampers, which act as insulation for the attenuation of vibration during breaker operation, is studied through testing and simulation. To obtain the nonlinear material constants required for the simulation, the biaxial tensile test was performed with urethane, which is a material used for dampers. The existing parts and the improved parts were compared and evaluated using the LS-DYNA program. As a result, 50% of the equivalent stress was reduced in the bracket body of the hydraulic breaker, and the equivalent stress of the side damper was also decreased. We verified that the fatigue conditions were satisfied by performing a fatigue analysis.