• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1083-1084
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• 2006

The wide spread of DC electric railway systems such as urban rapid transits including heavy rail and light rail transits has significant ramification as the stray currents from return conductor rails can cause the electrochemical interference, that is, the electrolytic corrosion of both rails and outside underground metallic infrastructures. The immature understanding of either the railway authority who is responsible for establishing the necessary provisions at the design stage or the affected parties makes it difficult to prepare the optimum range of solutions for the long-pending interference problem. In Japan, however, numerous assessment studies have been carried out on the stray current interference, by which protective guidelines are provided by "Electrolysis Committee". In this paper, we review a guide book from "Tokyo Electrolysis Committee", namely, "Protective Methods for Stray Current Corrosion".

• Geomechanics and Engineering
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• v.21 no.2
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• pp.143-152
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• 2020

Korean society experienced successive earthquakes exceeding 5.0 magnitude in the past three years resulting in an increasing concern about earthquake stability of urban infrastructures. This study focuses on the significant aspects of earthquake risk assessment for the cut-and-cover underground railway station based on two-dimensional dynamic numerical analysis. Presented are features from a case study performed for the railway station in Seoul, South Korea. The PLAXIS2D was employed for numerical simulation and input of the earthquake ground motion was chosen from Pohang earthquake records (M5.4). The paper shows key aspects of earthquake risk for soil-structure system varying important parameters including embedded depth, supported ground information, and applied seismicity level, and then draws several meaningful conclusions from the analysis results such as seismic risk assessment.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2682-2687
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• 2008

Depressurized drainage systems have been used for more than 30 years and are becoming a common part of urban drainage infrastructures. The hydraulic principles governing the operation of the depressurized drainage systems were studied in this paper and particularly, focused on the analysis of unsteady characteristics of the two-phase flow. A definition of the filling ratio was outlined and types of flow pattern were classified according to the filling ratio. Experiments were conducted to investigate the main features of pressure fluctuation. All results were found to depend on the filling ratio of the upstream pipe flow as well as the upstream Froude number.

• KCI Concrete Journal
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• v.11 no.3
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• pp.109-114
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• 1999

Recently the interest in the safety assessment of civil infrastructures has increased. As bridge structures become large-scale, it is necessary to monitor and maintain the safety of large bridges, which requires smart systems that can make long-term monitoring a reality . Civil engineers have applied monitoring systems to several bridges, such as the New Haeng-Ju Bridge and Riverside Urban Highway Bridge, but these applications have some problems with the sensors for long-term measurement, setup techniques for the bridge monitoring system and the assessment of measured data. In the present study, an optical fiber sensor smart system was tested and confirmed in laboratory tests on the concrete members. By Attaching optical fiber sensors to the structural parts of the Sung-San Bridge, the bridge load test was measured. These smart concrete structure systems can be applied to bridges and the load capacity of the bridge can assessed.

• International Journal of Advanced Culture Technology
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• v.9 no.1
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• pp.22-27
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• 2021

Morphology of contemporary city streets is composed of overlapping infrastructures corresponding to the new street within the established organization, contemporary system, future circumstance, and population. As well, two overlaid organizations and morphological, historical, social and physical development lead to sharp acute algle(triangular) site, and the architecture in this site has a restriction on the availability of the internal space and the external design due to outside shape sharpness. We want to have a positive effect on the internal and external design of the architecture in the future by categorization of the shape and processing characteristics of the acute angle corner of the trilateral site. The characteristics and design categorization shown in this case study are as follows. Constitution a unique and independent form, lead streets and shape a exclusive image of the landscape, alleviate sharpness by configuring a acute angle point as a plane, use void to give reserve character, replace roundness for companionability to induce ambience in the road, embrace the characteristics of the site and create internal spaces and functions, emphasize the characteristics of each stairs, retain of uniqueness and highlight the characteristics of a vertical elements.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.32-39
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• 2009

"We need to overcome the lack of space and infrastructure." Construction in the 20th century had been basically motivated by this need. It had enabled almost automatic financing on land as well as plenty of public investment. However we cannot expect such investment in built environment any more in the 21st century, when urban structures have been fully built. "We have space and infrastructures but want to make them better." We must find the new way how to strategically organize creativity on use as well as such users' want itself for sustaining investment in built environment. In this paper the outline of such a new way is discussed.

• Structural Engineering and Mechanics
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• v.44 no.1
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• pp.51-60
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• 2012

Concrete sleepers are essential components of the conventional railway. As support elements, sleepers are always subjective to a variety of time-dependent loads attributable to the train operations, either wheel or rail abnormalities. It has been observed that the sleepers may deteriorate due to these loads, inducing the formation of hairline cracks. There are two areas along the sleepers that are more prone to crack: the central and the rail seat sections. Several non-destructive methods have been developed to identify failures in structures. Health monitoring techniques are based on vibration responses measurements, which help engineers to identify the vibration-based damage or remotely monitor the sleeper health. In the present paper, the dynamic effects of the cracks in the vibration signatures of the railway pre-stressed concrete sleepers are investigated. The experimental modal analysis has been used to evaluate the modal bending changes in the vibration characteristics of the sleepers, differentiating between the central and the rail seat locations of the cracks. Modal parameters changes of the 'healthy' and cracked sleepers have been highlighted in terms of natural frequencies and modal damping. The paper concludes with a discussion of the most suitable failure indicator and it defines the vibration signatures of intact, central cracked and rail seat cracked sleepers.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1933-1942
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• 2008

Over the years, the Social Republic of Vietnam has demonstrated its high annual growth rate over 8%. In order to secure its sustainable economic growth, its has also demonstrated its sharp concerns on building up core infrastructures by luring foreign investments on a large scale, which would underpin the nation's economic propulsion. Among others, transport infrastructures and networks centering on railway systems are obviously seen as the most urgent to be built to continue its growth. Seoul Metro recently took a significant step forward in Vietnam to launch railway business by executing its export project of 6 units of metro cars to Hanoi as on July 10, 2008. Those 6 cars are scheduled to be put on the tracks linking Yen Bian, Hanoi with Ha Long, for demonstrative running, around October, 2008, carrying tourists on that 163kms of the National Railway line serving the region. A successful running on the track will duly entail further export of additional 54 units of Seoul Metro cars to Vietnam. In this thesis, description will be noted on the reuse and economic value of the Seoul Metro's de-commissioned metro cars, reflecting on the current urban railway law at home regulating the service life of rolling stocks domestically. This thesis will also study the points at issue, and the recommendable future orientation of the Vietnam railway business project.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.92-101
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• 2007

Urban freight system includes not just intra-urban freight movement but also inter-urban movement as well. Hence, to make Busan a hub of North-east asia freight movement it is necessary to develop a comprehensive plan for infrastructure expansion as well as improvement of freight system based on the present facility situation. This study identifies the status of freight facilities in Busan by establishing the freight related infrastructure Database(DB) utilizing Geographic Information System(GIS), and to enable planners and decision-makers to utilize the DB to develop a future plan. The DB includes port facilities, major and minor arterial roads, railroad lines and facilities, depots, center city business areas, and urban infrastructures which are related to the freight movements. The analyses show that major transportation facilities in Busan consist of roads, railroads, coastal transportation, and international transportation, and it was found that intermodal facilities are inadequate for freight system in Busan. The results of this study will be useful for freight experts and planners to develop a comprehensive freight system plan.

• Journal of Korean Society of Transportation
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• v.36 no.1
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• pp.23-37
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• 2018

In recent years, it is very difficult to construct and expand new infrastructures in a city center because of long-term low growth and lack of space due to urban overcrowding. So, there is a need to study a variety of Retrofitting techniques and urban applications that can lead to sustainable development while efficiently utilizing existing facilities. 'Retrofit' means a sustainable urban retrofitting as a directed alteration of the structures, formations and systems of existing facilities to improve energy, water and waste efficiencies. In this study, we applied a hierarchical network design technique that can reflect the structural hierarchy of a city to study how to retrofit public transportation routes in Seoul. The hierarchical network design means dividing the hierarchy according to the functions of hubs and connecting different hierarchies to form a hierarchical network. As a result of comparing the application results of various retrofitting scenarios of public transport, the differences of daily PKT and PHT by about 2.6~3.2% less than before the improvement address that the convenience of passengers is increased. Therefore, it is expected that if the route planning is established according to the proposed method, it will increase the number of passengers and the operational efficiency by the improved convenience of public transit passengers.