• Land and Housing Review
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• v.12 no.3
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• pp.97-108
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• 2021

In bridge abutment structures, lateral squeeze due to lateral stress of embankment placement and thermal movement of the bridge structure leads to failure of approach slabs, girders, and bridge bearings. Recently, GRS (Geosynthetic-Reinforced Soil) integral bridge has been proposed as a new countermeasure. The GRS integral bridge is a combining structure of a GRS retaining wall and an integral abutment bridge. In this study, numerical analyses which considered construction sequences and earthquake loading conditions are performed to compare the behaviors of conventional PSC (Pre-Stressed Concrete) girder bridge, traditional GRS integral bridge structure and GRS integral bridge with bracket structures (newly developed LH-type GRS integral bridge). The analysis results show that the GRS integral bridge with bracket structures is most stable compared with the others in an aspect of stress concentration and deformation on foundation ground including differential settlements between abutment and backfill. Furthermore, the GRS integral bridge with/without bracket structures was found to show the best performance in terms of seismic stability.

• Strategy21
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• s.31
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• pp.120-141
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• 2013

Korea, China, and Japan forms triangle structure which mixed complicatedly on the history and maritime territorial disputes. Nationalism lies on the basis of triangle structure, and it is a main factor which increase tension and conflicts among three countries. Considering dynamics of changing nationalism circumstance, Ieodo issue needs to prepare active countermeasures which considers cope with nationalism confrontations. The aim of this article is suggests preparations of active countermeasures cope with nationalism provocative actions. First, I will specify nationalism as a factor of territorial dispute, and review characters of Ieodo issue. Second, I will analyse China's nationalism to Ieodo through analysis of China's media contents and coverage trend of Ieodo issue (2006~2008). I will suggest necessity of active defense measures coup with China's nationalism, basis of these analysis. As a result, China's nationalism might be a criterion which measures of China's desire for Ieodo. Stimulating Ieodo coverage of China's state media can be a criterion which predicts China governments's for Jurisdiction of Ieodo. We need active measures coup with China's nationalism Which evolves into a much more bold and assertive.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.694-698
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• 2006

This paper presents an optimal design process using beads on a body panel to improve interior noise of a passenger vehicle. Except modification of structural members, it is difficult to find effective countermeasures that can work for the intermediate frequency range from 100 Hz to 300 Hz which lies between the booming and low medium frequency. In this study, it is a major goal to find additional counter-measures for this intermediate frequency range by performing optimal design of beads on body panels. The proposed method for design optimization consists of 4 sub-steps, that is, a) problem definition, b) cause analysis, c) countermeasure development and d) validation. The objective function is minimization of interior noise level. The major design variables are the geometrical shape of a bead and combination of beads on the critical panels. Sensitivity analysis and optimization are performed according to the predefined process for an optimal design. It is verified that the proposed design decreases the level of noise transfer function above 5 dB.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.102-106
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• 2007

To apply the flux-lock type superconducting fault current limiter(SFCL) into power system, its current and voltage ratings are required to increase. Especially, in case of series connection of SFCLs, the countermeasure for simultaneous quenches must be considered. The structure, which each flux-lock type SFCL unit was wound in series on the same iron core, can induce the simultaneous quench of superconducting elements. Through the fault current limiting experiment for the suggested structure, it was confirmed that the even voltage burden among the superconducting elements comprising SFCLs could be made.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.974-979
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• 2008

A design process for the structure-borne noise in a passenger vehicle is presented. The proposed process is improved from the previous one. The major difference between the current and last ones is that most of the countermeasures should be developed before fixing a tool for structural parts. This is requested for QCDP(Quality, Cost, Delivery and Productivity) by the design engineers. The proposed one consists of 4 steps: Problem definition, Cause analysis, Development of counter-measure and Validation. Based on the general rule: divide and conquer, the complex problem can be simplified into a few critical sub-systems through the first step: Problem definition. Secondly, the critical causes can be identified for the critical sub-systems through the second step: Cause analysis. Thirdly, effective countermeasures are investigated and produced through the third step: Countermeasure development. The proposed countermeasures are finally validated in the forth step: Validation.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.476-480
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• 2010

In the corrugated steel panels used for railway vehicles, sound insulation performance is significantly deteriorated by local resonance effect. In this study, as a countermeasure, polyurethane foam is filled in the corrugated steel panel and glass wool layer is inserted in the layered floor panel, and then improvement effect of the sound insulation performance is experimentally estimated. Based on ASTM E2249-02, intensity transmission loss is measured and estimated on the corrugated panel and floor structure. The aim of the study is to identify how the foam filling and inserting glass wool layer improve the sound insulation performance of the train body structure in aspect of the weight increment.

• Progress in Superconductivity and Cryogenics
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• v.18 no.2
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• pp.18-20
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• 2016

The study of superconducting fault current limiter (SFCL) is continuously being studied as a countermeasure for reducing fault-current in the power system. When the fault occurred in the power system, the fault-current was limited by the generated impedance of SFCLs. The operational characteristics of the flux-offset type SFCL according to turn ratios between the primary and the secondary winding of a reactor were compared in this study. We connected the secondary core to a superconductor and a SCR switch in series in the suggested structure. The fault current in the primary and the secondary winding of the reactor and the voltage of the superconductor on the secondary were measured and compared. The results showed that the fault current in the load line was the lowest and the voltage applied at both ends of the superconductor was also low when the secondary winding of the reactor had lower turn ratio than the primary. It was confirmed based on these results that the turn ratio of the secondary winding of the reactor must be designed to be lower than that of the primary winding to reduce the burden of the superconductor and to lower the fault current. Also, the suggested structure could increase the duration of the limited current by limiting the continuous current after the first half cycle from the fault with the fault current limiter.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.66-71
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• 2007

Human error is one of the major contributors to the railway accidents or incidents. In order to develop an effective countermeasure to remove or reduce human errors, a systematic analysis should be preferentially performed to identify their causes, characteristics, and types of human error induced in accidents or incidents. This paper introduces a case study for human error analysis of the railway accidents and incidents. For the case study, more than 1,000 domestic railway accidents or incidents that happened during the year of 2004 have been investigated and a detailed error analysis was performed on the selected 90 cases, which were obviously caused by human error. This paper presents a classification structure for human error analysis, and summarizes the analysis results such as causes of the events, error modes and types, related worker, and task type.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.515-520
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• 2011

The Climate Change has been emerged as one of the most important social and economic issues and is affecting our daily life. The Post-Kyoto Protocol aims to reduce GHG(Greenhouse Gas) emission and mitigate climate change. Under this protocol, developed countries which are classified as Annex I implements programmes and strategies confronting against the climate change. South Korea has set voluntary GHG reduction goal of 30% reduction compared to BAU(Business As Usual) in 2020 and prepares National GHG inventory system and Negotiated Agreements(NA) with industries. It will affect seriously to industry and transport sector and its obligation to reduce GHG emission will be strengthened gradually. Therefore, there will be large impact on industry structure. In Korea, various strategies against climate change are being prepared as researches of development of GHG emission reduction technologies and integrated GHG emission management system in transport sector. In this study, strategy on climate change in transport sector is proposed by being based on developed countries' respond to climate change in transport sector.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.753-756
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• 2011

Recently the construction of railway sections passing the central area of cities and stations under railway lines are increasing, and then it is urgently required to take the countermeasures against the railway vibration and the second-phase noise radiated from it. The most efficient countermeasure, out of technologies developed up to now, is the floating slab track which is the track system isolated from the sub-structure by springs. In other countries, the source technologies for anti-vibration design and vibration isolator - one of key components - have been developed and many installation experiences have been accumulated. However, in Korea, since the system design technology and technologies for key components are not yet developed, the foreign system are being introduced without any adjustment, and the key component, vibration isolator, depends on imports. In this study, analysis on floating slab system installed rubber mat and stopper is carried for the examination on the safety of floating slab system.