• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.3-14
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• 2005

Reliable predictions of the movement of earth retaining structures and the ground adjacent to braced walls in urban excavation are often difficult due to many variable factors. The ground settlement and the damage of adjacent structures in urban excavation has been an important issue. Therefore, the stability of the adjacent structures must be secured with the excavation support and research on the protection of adjacent structure is necessary. This study showed an urban excavation case and introduce observation method for case of damage behavior in urban excavation.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1539-1543
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• 2011

Due to recent large earthquakes around the world, there are increasing social needs for seismic safety of urban railway infrastructures. Urban railway infrastructures are applied different seismic performance evaluation procedure each of overground structures, underground structures and bridge structures, and the characteristics of urban railway infrastructures are not properly considered in the procedure. This study presents problems in the existing seismic performance evaluation procedure of urban railway infrastructures and proposes necessities of unified evaluation procedure.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.49-83
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• 2005

ESCP Project showed an urban excavation case and introduced design method for case of Soil-Structure behavior in urban excavation. In this case, a retaining structures design to analysis the behavior of retaining wall and adjacent structures in urban excavations was applied by using a Elasto-plastic beam and limit Equilibrium analysis and soil-structure interaction analysis. Reliable design of earth retaining structures and the ground adjacent to braced wall in urban excavation are often difficult due to many variable factors. The ground settlement and the damage of adjacent structures in urban excavation has been an imprtant issue. Therefore, the stability of the adjacent structures must be secured with the excavation support and research on the protection of adjacent structure is necessary.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.107-111
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• 2008

This paper presented a literature review and investigation analysis results of total 19 present guide book and provisions of maintenance and management system in existing railway bridges to development of urban maglev track structures inspection manual. This research carried out a cooperated research subject 3-1, development a design code and maintenance and management inspection manual for urban maglev track structures, of the Center for Urban Maglev Program. Three types of track structures were includes as a major analytical parameter together with railroad, high speed railroad, subway and light rail transit. Bridges were analyzed a general rules, investigation, evaluation, repair and strengthen method as a key aspect. And rail were analyzed examination and maintenance also. This analysis results show that the track structures evaluation are based on the test and examination results, and repaired or strengthened consideration of deterioration, track irregularity and materials according to provision requirements.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.493-500
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• 2001

The construction of bored tunnels in soft ground inevitably causes ground movements. In the urban environment these may be of particular significance, because of their influence on buildings, other tunnels and services. The prediction of ground movements and the assessment of the potential effects on the structures is therefore an essential aspect of planning, design and construction of a tunnelling project in the urban environment. In this study, to minimize the effect of tunnelling-Induced ground movements on the adjacent structures, a system for tile settlement risk management was developed. The GIS based risk assessment system for adjacent structures developed in this study consists of several modules such as building information module, settlement evaluation module, potential risk assessment module for adjacent structures, and analysis module for monitoring data. This system focuses on controlling and managing construction processes that may lead to settlement In the surrounding buildings and can contribute to producing the optimum technical and economic design.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.330-335
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• 2005

Reliable predictions of the movement of earth retaining structures and the ground adjacent to braced walls in urban excavation are often difficult due to many variable factors. The ground settlement and the damage of adjacent structures in urban excavation has been an important issue. Therefore, the stability of the adjacent structures must be secured with the excavation support and research on the protection of adjacent structure is necessary. This study showed a countermeasure method for case of damage behavior in urban excavation.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1318-1327
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• 2008

Geotechnical sites in urban areas may have embedded structures such as utility lines and underground concrete structures, which cause difficulties in site investigation. This study is a preliminary research to establish knowledge base for developing an optimal technique for site investigation in urban areas. Surface-wave method and resistivity survey, which are frequently adopted for non-destructive site-investigation for geotechnical sites, were investigated to characterize effects of adjacent structures. In case of surface wave method, patterns of wave propagation were investigated for typical sets of multi-layered geotechnical profiles by numerical simulation based on forward modeling theory and field experiments for small-size model tests and real-scale tests in the field. In case of resistivity survey, 3-D finite element analyses and field tests were performed to investigate effects of adjacent concrete structures. These theoretical and experimental researches for surface-wave method and resistivity survey resulted in establishing physical criteria to cause interference of adjacent structures in site investigation at urban areas.

• Journal of Ocean Engineering and Technology
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• v.29 no.5
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• pp.392-397
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• 2015

An autonomous underwater vehicle (AUV) can perform flexible operations even in complex underwater environments because of its autonomy. Localization is one of the key components of this autonomous navigation. Because the inertial navigation system of an AUV suffers from drift, observing fixed objects in an inertial reference system can enhance the localization performance. In this paper, we propose a method of AUV localization using visual measurements of underwater structures. A camera measurement model that emulates the camera’s observations of underwater structures is designed in a particle filtering framework. Then, the particle weight is updated based on the extracted visual information of the underwater structures. The proposed method is validated based on the results of experiments performed in a structured basin environment.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.2
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• pp.109-113
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• 2004

It is important to consider urban parks and greenery not only from the viewpoint of amenity or aesthetics but also from the viewpoint of biodiversity. In this study, we focused on bryophytes (mosses), and analyzed how existence of artificial structures in urban greeney, such as concrete curbs and stone walls, affect species diversity of bryophytes. Kyoto Gyoen in Kyoto City, western Japan, was selected as the study site. In consideration of kinds of substrates on which bryophytes grow, microhabitats of Kyoto Gyoen were divided into ten types including concrete curbs and stone walls. In each type of microhabitats, we selected the area where bryophyte diversity was highest, and established a quadrat for bryophyte flora survey. Our results showed that the number of bryophyte species and growth forms and the value of diversity indices on concrete curbs or stone walls were higher than the averages of those. The bryophyte species were divided into the four groups by TWINSPAN as follows: Group A (epiphyte species), Group B (rocky species), Group C (roadsides, grassland or forest species), and Group D (waterside species). Bryophytes classified into Group B (rocky species) were mainly recorded on concrete curbs or stone walls. It was considered that the existence of artificial structures (concrete curbs and stone walls) provided favorite habitats for the bryophytes classified into Group B (rocky species), which mainly grows on concrete or rocks, and enhanced species diversity of bryophytes in Kyoto Gyoen.

• Structural Monitoring and Maintenance
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• v.5 no.2
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• pp.313-323
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• 2018

The presence of water inside concrete structures is an essential condition for the deterioration of the structures. The free water in the concrete pores and micro-cracks is the culprit for the durability related problems, such as alkali-aggregate reaction, carbonation, freeze-thaw damage, and corrosion of steel reinforcement. To ensure the integrity and safe operation of the concrete structures, it is very important to monitor water seepage inside the concrete. This paper presents the experimental investigation of water seepage monitoring in a concrete slab using piezoelectric-based smart aggregates. In the experimental setup, an $800mm{\times}800mm{\times}100mm$ concrete slab was fabricated with 15 SAs distributed inside the slab. The water seepage process was monitored through interrogating the SA pairs. In each SA pair, one SA was used as actuator to emit harmonic sine wave, and the other was used as sensor to receive the transmitted stress wave. The amplitudes of the received signals were able to indicate the water seepage process inside the concrete slab.