• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.3
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• pp.355-373
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• 2017

Tunnelling in urban areas, it is essential to understand existing structure-tunnel interactive behavior. Serviced structures in the city are supported by pile foundation, since they are certainly effected due to tunnelling. In this research, thus, pile load distribution and ground behavior due to tunnelling below grouped pile were investigated using laboratory model test. Grouped pile foundations were considered as 2, 3 row pile and offsets (between pile tip and tunnel crown: 0.5D, 1.0D and 1.5D for generalization to tunnel diameter, D means tunnel diameter). Soil in the tank for laboratory model test was formed by loose sand (relative density: Dr = 30%) and strain gauges were attached to the pile inner shaft to estimate distribution of axial force. Also, settlements of grouped pile and adjacent ground surface depending on the offsets were measured by LVDT and dial gauge, respectively. Tunnelling-induced deformation of underground was measured by close range photogrammetric technique. Numerical analysis was conducted to analyze and compare with results from laboratory model test and close range photogrammetry. For expression of tunnel excavation, the concept of volume loss was applied in this study, it was 1.5%. As a result from this study, far offset, the smaller reduction of pile axial load and was appeared trend of settlement was similar among them. Particulary, ratio of pile load and settlement reduction were larger when the offset is from 0.5D to 1.0D than from 1.0D to 1.5D.

• Explosives and Blasting
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• v.23 no.3
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• pp.83-89
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• 2005

It follows in deterioration of the steel frame structure and becomes remodeling and removal. The construction work characteristic, economical efficiency and stability environment characteristic are planned and considered hereafter control plan of the steel frame structure which is deteriorated currently to cutting mettled plentifully sued on gas cutting of H beam. However it will not be able to apply from the explosives demolition which is makes a weak instantaneously and then collapses the building at the time. In this study, shape charge was used for cutting of the H-beam. That is the element testing to estimate explosives demolition for steel frame structure. As a result, it is found for single-side rutting method, both-sides rutting methods by H-beam thickness and pre-rutting process. It confirmed an affix method and an ease characteristic by fixing tool. Also, it is shown that air blasting decreased about 8dB(A) in order to reduce air blasting used by sand box. However, it will be required to reduce air blasting little more because explosives demolition will be done in urban site.

• Steel and Composite Structures
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• v.13 no.6
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• pp.501-519
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• 2012

As an alternative to current conventional force-based assessment methods, the energy-based seismic performance of a code-designed 20-storey high-rise steel building is evaluated in this paper. Using 3D nonlinear dynamic time-history method with consideration of additional material damping effect, the influences of different restoring force models and P-${\Delta}/{\delta}$ effects on energy components are investigated. By combining equivalent viscous damping and hysteretic damping ratios of the structure subjected to strong ground motions, a new damping model, which is amplitude-dependent, is discussed in detail. According to the analytical results, all energy components are affected to various extents by P-${\Delta}/{\delta}$ effects and a difference of less than 10% is observed; the energy values of the structure without consideration of P-${\Delta}/{\delta}$ effects are larger, while the restoring force models have a minor effect on seismic input energy with a difference of less than 5%, but they have a certain effect on both viscous damping energy and hysteretic energy with a difference of about 5~15%. The paper shows that the use of the hysteretic energy at its ultimate state as a seismic design parameter has more advantages than seismic input energy since it presents a more stable value. The total damping ratio of a structure consists of viscous damping ratio and hysteretic damping ratio and it is found that the equivalent viscous damping ratio is a constant for the structure, while the equivalent hysteretic damping ratio approximately increases linearly with structural response in elasto-plastic stage.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.5
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• pp.325-330
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• 2014

The era of convergence is being applied to all areas of Information and Communication Technology (ICT). The convergence of broadcasting service and communication service almost occurs on smart devices including smartphone. The smart hybrid Digital Multimedia Broadcasting (DMB) is a typical example of the convergence of broadcasting and wireless communication service. The hybrid mobile broadcasting service can support seamless video, 3D, high quality, and additional data services based on network connection between the broadcasting and wireless network. The gateway and terminal (including apps on the smartphone) take the role of the main components on the hybrid service. This paper presents the service concept, main components structure, the implementation of gateway and terminals, and field test to the urban areas for the mobile hybrid system.

• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1139-1149
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• 2017

Measuring tree's volume is very important input data of various environmental analysis modeling However, It's difficult to use economical and equipment to measure a fragmented small green space in the city. In addition, Trees are sensitive to seasons, so we need new and easier equipment and quantification methods for measuring trees than lidar for high frequency monitoring. In particular, the tree's size in a city affect management costs, ecosystem services, safety, and so need to be managed and informed on the individual tree-based. In this study, we aim to acquire image data with UAV(Unmanned Aerial Vehicle), which can be operated at low cost and frequently, and quickly and easily quantify a single tree using SfM-MVS(Structure from Motion-Multi View Stereo), and we evaluate the impact of reducing number of images on the point density of point clouds generated from SfM-MVS and the quantification of single trees. Also, We used the Watertight model to estimate the volume of a single tree and to shape it into a 3D structure and compare it with the quantification results of 3 different type of 3D models. The results of the analysis show that UAV, SfM-MVS and solid model can quantify and shape a single tree with low cost and high time resolution easily. This study is only for a single tree, Therefore, in order to apply it to a larger scale, it is necessary to follow up research to develop it, such as convergence with various spatial information data, improvement of quantification technique and flight plan for enlarging green space.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.6
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• pp.3-14
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• 2018

The aim of this study is to propose a method for calculating the weight of walking energy in ERAM model by calculating it for the analysis of vertical and horizontal spaces in a building. Conventional theories on the space analysis in the field of architectural planning predict the pedestrian volume of network spaces in urban street or in two-dimensional plane within a building, however, for vertical and horizontal spaces in a building, estimates of the pedestrian volume by those theories are limited. Because in the spatial syntax and ERAM model have been applied weights such as the spatial depth, adjacent angles, and physical distances available only to the two-dimensional same layer or plane. Therefore, the following basic assumptions and analysis conditions in this study were established for deriving a predictor of pedestrian volume in vertical and horizontal spaces of a building. The basic premise of space analysis is not to address the relationship between the pedestrian volume and the spatial structure itself but to the properties of spatial structure connection that human beings experience. The analysis conditions in three-dimensional spaces are as follows : 1) Measurement units should be standardized on the same scale, and 2) The connection characteristics between spaces should influence the accessibility of human beings. In this regard, a factor of walking energy has the attributes to analyze the connection of vertical and horizontal spaces and satisfies the analysis conditions presented in this study. This study has two implications. First, this study has shown how to quantitatively calculate the walking energy after a factor of walking energy was derived to predict the pedestrian volume in vertical and horizontal spaces. Second, the method of calculating the walking energy can be applied to the weights of the ERAM model, which provided the theoretical basis for future studies to predict the pedestrian volume of vertical and horizontal spaces in a building.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.39-47
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• 2022

Digital Twin is positioned as one of the establishment of a digital management system for core infrastructure in terms of collecting real data and implementing virtual space. However, there are currently no integrated three-dimensional marine information analysis tools and technologies in Korea, and unlike land, new 3D modeling technologies and data processing technologies are required to digitize flexible marine information, but there are limitations in implementation. Therefore, this study aims to present development directions in four areas: structure, data, modeling, and utilization platform of marine digital twin by analyzing trends related to marine digital twin and digital twin technology elements.

• Environmental Engineering Research
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• v.18 no.3
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• pp.117-121
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• 2013

For underpasses in Yeongjong Sky City business district, the guided drainage system, as a buoyancy prevention system has been designed, and is under construction. This paper investigates the safety of the guided drainage system for underpass structures being constructed in Yeongjong Sky City business district. This paper also calculates the amount of outflowing groundwater generated by the guided drainage system, and proposes alternative usages of the water. In order to investigate safety and field applicability of the guided drainage system for underpasses, characteristics of the surface flow for the area of interest have been analyzed, and the flow change of groundwater following the underpass structure construction has been evaluated using the 3-dimensional groundwater program MODFLOW. The influence of ground water on safety of the underpass structures has been calculated by FLAC2D analysis. For alternative usages for the outflowing groundwater generated by the guided drainage system, utilization methods of the outflowing groundwater in national and international resources have been researched. The amount of an outflowing groundwater to be generated in the area of interest has been analyzed, and efficient potential usages of this groundwater have been researched. When guided drainage technique is applied, the change in flow of groundwater must be evaluated and considered as safety factor relating to the buoyancy of the structure. As a result, safety factor demonstrated more than 1.2, meaning that the underpass structure is safe. The amount of subsoil drain generated by the guided drainage system was also analyzed. The quality and amount of water satisfied the standards and volume requirements, so as to make it applicable for a number of uses, such as X, Y, and Z, and should prove to be a valuable resource as the circumstances of the neighboring area change over time. These resources can be used as basic data for future urban water circulation studies, as well as generating research of alternative water usages.

• KIEAE Journal
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• v.12 no.6
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• pp.77-84
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• 2012

The current architectural design of unit modular has been based on 2D of CAD program, so unit modular character which needs unit information management, as a dried-member system, has no effect on design process. The purpose of this study is We have developed a suitable BIM design process, according to various works of construction, then tried to contribute to supply and activation of the urban-life-housing based on unit modular. The BIM modeling process based on unit modular has been in order of unit combination with preparing manual classification, and, it has been constructed, at construction site, from housing foundation to roof finish by Bottom-up method. At a manufacturing factory, it has been produced in order of 1) grouping materials and parts, 2) fabricating unit boxes, and 3) interference examination of unit boxes, and each order has been classified as housing structure, architecture, plumbing process separately. At a construction site, the fabrication has been done in order of, like as a real housing construction scenario, 1) RC foundation work 2) unit module job-site-fabrication work, 3) roof truss work, 4) plumbing and HVAC work, and 5) housing interior finish work. After modeling process, the interference examination on each work of construction has finally completed modeling. The Unit modular utilizing BIM modeling can make easy housing maintenance through systematic control with preparing manual of unit module information, and securing accurate and speedy construction information. And it will promote design credibility and create maximum effect of unit modular construction method, such as construction period reduction and upgrade of construction quality, etc., through the computer simulation as real as construction environment in cyber space, and with the interfering examination.

• Land and Housing Review
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• v.3 no.3
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• pp.299-305
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• 2012

Various types of bio wood chip for fermentation-extinction of food waste was investigated by comparing their different pore structure with the performance of weight loss rate and microbial activity. The fermentation-extinction of food waste with bio wood chip was examined by adding 700~1,500g of food waste every day during 15 days to the fermentation-extinction reactor with condition of $30{\sim}50^{\circ}C$ temperature and 30~70% humidity, where 1,500g of bio wood chips were existed. The bio wood chips used in this experiment were categorized into 4 different types; microbial-mixing type(A biochip), macro pore type(B biochip) under $2{\mu}m$ of pore size, micro pore type of wood-chips(C biochip) under $0.1{\mu}m$ of pore size, viscous & sticky type(D biochip). As a result, A, B, C, D bio wood chip exhibited 85%, 63%, 92%, 73% weight loss of food waste with fermentation-extinction. The maximum weight loss of food waste was obtained at the fermentation-extinction experiments by using C bio wood chip. On the other hands, the maximum ratio of ATP to COD and TN was obtained from $3.00{\times}10^{-10}$ and $2.31{\times}10^{-11}$ in the case of C bio wood chip, comparing with other types of bio wood chip. Consequently, the performance of weight loss rate was affected with the micro pore structure of bio wood chip which have an advantage of extensive microbial activity space in the fermentation-extinction of food waste.