• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.640-655
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• 2018

Recently, the construction of the urban area has been rapidly increasing, and the excavation work of the ground has been frequently performed at the upper part of the existing underground structures. Especially, when the structure is constructed after the excavation of the ground, the loading and unloading process in the ground under the excavation basement can affect the existing underground structures. Therefore, in order to maintain the stability of the existing underground structure due to the excavation of the ground, it is necessary to accurately grasp the influence of the excavation and the structure load in the adjoining part. In this study, the effect of the excavation of the ground and the new structure load on the existing tunnel was experimentally implemented and the influence of the adjacent construction on the existing tunnel was investigated. For this purpose a large testing model with 1/5 scale of the actual size was manufactured. The influence of ground excavation, width of the load due to new structure, and distance between centers of tunnel and of excavation on the existing tunnel was investigated. In this study, it was confirmed that the influence on the existing tunnel gets larger, as the excavation depth get deeper. At the same distance, it was confirmed that the tunnel displacement increased up to three times according to the increase of the building load width. That is, the load width influences the existing tunnel larger than the excavation depth. As the impact of the distance between centers of tunnel and of excavation, it was confirmed that tunnel crown displacement decreased by 48%. The result showed that a tunnel is located in the range of 1D (D: tunnel diameter) from the center of excavation, the effect of excavation is the largest.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.3
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• pp.293-300
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• 2015

In this study, a series of forced vibration testing and ambient vibration measurement were performed at a lowrise masonry-infilled reinforced concrete frame structure before and after seismic retrofit and its dynamic properties were extracted using system identification techniques. Also, analytical models which show similar dynamic properties to the measures ones were constructed. The system identification results showed that damping ratios in x direction along which the dampers were installed has been increased. From the comparison between the analytical models, the effective stiffness of post-installed member and post-reinforced members(shear walls and damper frames) were only 50% of gross sectional stiffness of the members, which indicates that the these members were not fully integrated with the existing structure or members. In addition, support condition of post-installed footing has to be pinned in y direction to match the dynamic properties, which is seemingly caused by the change of fixity of the soil due to the installation of new footing.

• International Journal of High-Rise Buildings
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• v.4 no.4
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• pp.291-310
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• 2015

It is common for tall buildings in Korea to have a ground response that is highly sensitive to the behavior of the structure. Therefore, the geology of the ground needs to be carefully assessed and considered in the design process to accurately predict the performance of the foundation system. This paper sets out a systematic design approach and ground investigation methodology for the soil conditions frequently encountered in Korea. Various foundation design methods are introduced along with several case studies conducted in Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.107-116
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• 2005

Korea has been suffering from various natural disasters. Slope-stability related disasters such as landslides usually occur during typhoon and torrential rain season. Types of slope-stability related disasters can be classified as failures in cut slopes along constructed roads, landslides in natural terrain, and retaining structure failures in urban area. This paper summarizes human casualties for the last 29 years in Korea, reviews field studies for the disaster sites that caused human casualties due to torrential rains in the Summer of 2005, analyzes causes of slope-stability related disasters and includes recommendations for an effective management system.

• Journal of the Korean Institute of Intelligent Systems
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• v.5 no.3
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• pp.92-100
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• 1995

Fuzzy reasoning has been applied to analysis of traffic problems on urban arterial road. As the analysis on factors of route choice has been already carried out, its result can be used for construction of the model. Route choice rate estimation by fuzzy reasoning was discussed from its structure and accuracy. The major objective of the study is to introduce some kinds of methods with fuzzy reasoning and to make their feature obvious. First, the production system model is introduced with consideration of reality to actual travel behavior. Second, overlapping areas of fuzzy language function are investigated. Finally, process of fuzzy reasoning was also considered. Five kinds of Fuzzy reasoning are compared to investigate in relation between shapes of membership function and estimation validity.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1880-1886
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• 2008

Recently, a railroad system has a big and complicated structure of specification. Therefore, traceability between specification need to be identified for design change management and this is many engineer's concerns. Traceability means technical relationship. This is to trace other specification or component connect with relevant problem in case some problem should be examined. Traceability between functional specification can be proved through functional analysis essentially. This study will introduce an application method of functional analysis in the case of practical use project of MAGLEV train. And we propose the guide to identify traceability between function through functional analysis.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.2
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• pp.161-173
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• 2013

When the ground is excavated near the pre-existing structures due to the region restricted condition such as urban area, the ground will be released by the excavation and the temporary wall will be deformed depending on the earth pressure. In this case, issues can be created in terms of stability of pre-existing structures. Firstly, the laboratory model tests were carried out to investigate the ground surface settlement due to the ground excavation according to the excavation methods in this study. Using the ground surface settlement results from model tests, numerical analyses were carried out to study the structure deformation due to the ground excavation according to the excavation methods. Finally, using the structure deformation results from numerical analysis, the damage assessment of structures was carried out by using the strain damage estimation criterion.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.1
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• pp.67-79
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• 2013

For the sake of the Transit-Oriented Development that has been prominent recently, an analysis of the spatial structures of transit centers, above all, should be carried out at a local level. This study, thus, analyzes the spatial structures of subway influence areas by applying a Geographically Weighted Regression (GWR) model to individual parcels. As a result of the validity analysis of the model, it has turned out that the subway influence areas have different characteristics respectively, and there is spatial heterogeneity even in the same single area. Also, the result of the comparison among models has proved that the GWR model is more adequate than the Ordinary Least Square (OLS) model and $R^2$ has been also increased in the GWR model. Then, the results have been mapped by means of the GIS, which have made it possible to understand the spatial structures at a local level. If the Transit-Oriented Development is fulfilled in consideration of the spatial structural characteristics of the subway influence areas drawn respectively from the model analysis, it will be helpful in adopting effective policies.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.632-637
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• 2018

AC 및 DC 전력공급구간에서 모두 주행이 가능한 AC/DC 철도차량은 추진제어장치 내부에 컨버터 및 인버터가 모두 구성되어 있다. 따라서 DC 철도차량에 비해서 구성이 복잡하며 각 전력공급 환경에 적합한 인버터 제어 방법이 요구된다. 본 논문에서는 각 전력공급구간에서 고려되어야 할 사항과 이에 대한 인버터 제어 방법에 대하여 기술하고 서울 1호선 및 4호선 철도차량에 적용한 결과를 분석하였다.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.477-482
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• 2022

The structure of the turnout track is very complex, so it is a facility that is more difficult to maintain and requires detailed management than a general track type. The purpose of this study is to analyze the effect on the deformation of the turnout system of the ground section due to the excavation work adjacent to the serviced urban railways. In this study, based on finite element analysis for each stage of adjacent excavation, the track deformation for each major location of turnout system was analyzed in consideration of the layout of the turnout system installed on the ground section, and the safety and stability was confirmed by comparing it with the track irregularity regulation. As a result of the study, it was found that the major construction stage affecting the track deformation of the turnout system on the ground section was the final stage of excavation. In addition, although the vertical displacement which is a vertical irregularity occurred relatively large, it was analyzed that the horizontal deformation was dominant overall, because of the excavation site is located on the side of the turnout system. In addition, it was analyzed that the amount of displacement at each major location of the turnout system is different, and there is a possibility that there may be a twist irregularity due to the deviation of the track deformation for each location according to the distance from the excavation site. Therefore, it was analyzed that it is necessary to classify and manage the importance of the track deformation of the turnout system of actual operating line, including additional displacement due to adjacent excavation, based on the track irregularity that has occurred at each location where the major deformation characteristics occur.