• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.3
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• pp.223-230
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• 2007

As the centralization of city, underground facilities is increasing and being more important. Although the importance of underground facilities map has been emphasized, there were many accidents related underground facilities. The inaccuracy of existing data and the carelessness of management caused many accidents. It is very important to update and to have high quality accuracy of underground facilities maps. But the underground facilities maps are mapped and updated by each institutes. So it is difficult to verify the accuracy of the data. In this study, Field Test is performed to analyze the horizontal accuracy of existing maps using Electromegnetic Induction Method, Total Station and GPS. Surveying of underground facilities in Seoul was performed for 6 institutes of underground facilities during 3 years. The aim of this study is to verify the horizontal accuracy of data and to improve the accuracy of underground facility maps. As the result of analysis, the horizontal accuracy of 6 underground facilities management institutes is 73 cm(2004), 78 cm(2005) and 75 cm(2006).

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.97-107
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• 2017

Recently, there have been a lot of incidents related to ground sinks in urban areas, but restoration work is complicated and inconvenience due to on-site control, and particularly, grouting and soil filling are generally applied as recovery measures, but when the grouting or the soil filling is carried out, material segregation phenomenon occurs in the ground or a lot of restoration amount is often required, depending on the state of sinks and the existence of groundwater under the ground and the soil can be lost due to the flow of the ground water, and thus the purpose of this study is to develop a pouch-type filler applied to a trenchless method for emergency reinforcement of the ground sinks with the aim of quick recovery of the ground sink in urban areas, and as a result, it was confirmed that compression strength and the expansion ratio were different according to the temperature of ground water and the compression strength and the expansion ratio could be controlled by mixing alumina powder.

• Korean Journal of Construction Engineering and Management
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• v.5 no.2 s.18
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• pp.136-143
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• 2004

This study presents a risk management methodology using fuzzy theory for early construction stage and is focused on risk identification and risk analysis. This study identifies various risk factors associated with activities clearly construction stage, then establishes the Risk Breakdown Structure(RBS) by classifying the risks into the three groups; Common risks, risks for Earth works, and risks for Foundation works. The risk analysis method presented in this study is based on the RBS that has two levels such as upper level and lower level. The risk exposure of lower level risk factors is assessed by fuzzy inference. The weight of risks is estimated by fuzzy measure. Then, the estimated risk exposures and weights are aggregated to assess the risk exposure of upper level risks by Choquet fuzzy integral. The risk exposure of upper level risks determine the priority of risk factors in view of risk management. This study performs case study to validate the proposed method. The result of case study shows that the methodology suggested in this thesis would be utilized well in evaluating risk exposure.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.64-71
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• 2011

Construction projects are becoming larger in size and higher in complexity. Operation and maintenance, therefore, is an important part in providing the serviceability of the built facility from the perspective of life-cycle. This paper presents a 3D graphic model-integrated data extraction for bridge maintenance. The 3D graphic model environment assigns attributes to the member blocks in CAD, and link the attributes to the data stored in a database. Then, the user can click the member block to extract the data associated with the attributes. A prototype has been developed to test the applicability of the 3D graphic model environment using CAD and web. Application of the system in an actual bridge construction showed that the 3D graphic model environment can help the user find necessary data at a shorter time, thereby increasing the effectiveness of operation and maintenance in bridge structures.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.58-66
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• 2009

Due to a shortage of professional labor and the stagnant construction industry in recent days, there has been an increasing demand for securing profitability through cost reduction. Though its importance in the cost and its great influence on the safety and durability of structures, the labor intensiveness of rebar work has caused a serious problem of rising cost accompanied by the loss of rebar materials. In the plant manufacturing process, rebar is cut and bent at the automated facilities and conveyed to the construction site, which makes it possible to manufacture higher-quality bars and to reduce the losses from rebar materials. Different from the expectation, however, this type of plant manufacturing still has not been active since its first introduction in 1990s. In this study, a research on the actual condition of rebar manufacturing plant has been implemented and a standardized rebar manufacturing has been provided as a way to activate rebar manufacturing.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.127-134
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• 2009

This study aims to provide an optimal model for the layout of multiple tower cranes and material stockyards which have multiple candidate positions. In a high-rise building construction, the positional allocation of tower cranes and material stockyard has an effect on the travel time of material hauling. In addition, in case of using multiple tower cranes, specific location of a tower crane allocated to each material determines the efficiency of the works. Current optimal model limited to the optimization of position of single tower crane and material stockyards. This study suggests optimal model both for the positions of multiple tower cranes and material stockyards. Layout of multiple tower cranes requires additional allocation of each crane to each material hauling and control on the minimum distance between tower cranes. This optimization model utilizes genetic algorithm to deal with complex interaction on the candidate positions of multiple tower cranes, material stockyards, and types of materials. In order to identify its utility, case study was performed.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.152.1-152.1
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• 2012

한국형발사체개발사업은 대형복합시스템 사업이며, 장기간에 걸쳐 개발이 진행되는 사업이다. 따라서 사업적, 기술적 측면의 불확실성과 위험 등이 존재하며, 이를 적절히 관리 통제하지 못하면 비용 상승, 일정 지연 및 기술성능 요구조건 등의 불만족을 초래한다. 따라서 개발사업 초기단계에서부터 일정, 비용, 기술성능 및 위험관리 등을 위한 종합적 사업관리시스템 구축 및 운용은 개발사업 성공의 주요 관건이다. 현재 한국형개발사업단에서는 이러한 요구조건을 만족시키기 위한 일환으로써 일정 및 비용에 대한 효과적 관리시스템인 EVMS(Earned Value Management System)을 구축하여 운용 중에 있으며, 한국형개발사업에 맞는 최적화된 EVMS을 구축하기 위하여 시스템 커스터마이징 작업을 수행 중에 있다. EVMS의 구축과정에서 가장 고심했던 문제는 WBS 개발과 성과(Earned Value) 측정방법의 선정이었다. WBS의 경우, 개발초기단계에서부터 사업 전체를 포괄하는 완벽한 WBS을 개발하는 것은 상당히 어려운 문제이다. 그러나 사업초기에 존재하는 불확실성 및 위험에도 불구하고 개발을 계속 진행해야 하는 상황은 개발 현장에서 자주 접하게 되는 문제이다. 이러한 문제를 해결하기 위해서 적용하는 유용한 기법이 연동계획하기(Rolling Wave Planning)이다. 한국형개발사업을 위한 EVMS 구축과정에서도 이와 같은 문제에 봉착하게 되어 WBS 개발 시 연동계획하기(Rolling Wave Planning)기법을 적용할 예정이다. 성과(EV) 측정방법의 경우, 퍼센트완료기법과 마일스톤+퍼센트완료기법 등을 선정하여 적용 중에 있다. 현재 연구개발사업의 특성을 고려하여 우선 퍼센트완료기법을 적용하여 성과를 측정하였으나, 성과측정 결과의 주관성 문제로 인하여 마일스톤+퍼센트완료기법을 적용하여 성과(EV) 측정 결과의 객관성을 최대한 확보 할 예정이며, 최종적으로 한국형개발사업에 최적화된 성과측정 기법을 개발할 예정이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.270-273
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• 1999

Y2k will be able to enormous disaster. The many make an effort to find a solution to problem of Y2k. Problem of Y2k must solution to as follow. First, problem of Y2k solution organization must constructed. Second, in step with each stage-the first, developing and complete stage, stage of Y2k solution must be constructed. Third, solution of Y2k must construct to hierarchy. hierarchy structure constructed form six stage to first stage, first stage is investigation resources, second stage is estimation influence, third stage is planing conversion, fourth stage is working conversion, fifte spot, sixth stage is diffusion on the spot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7941-7948
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• 2015

Rolling noises during train operation are caused by vibration excited from irregularities of surface roughness between wheel and rail. Therefore, a proper measurement and analysis techniques of acoustic roughness between wheel and rail surface are required for transmission, prediction, and analysis of the train rolling noise. However, since current measuring devices and methods use trolley-based manual handling devices, the measurements induce unstable measuring speed and vibrational interface that increases errors and disturbances. In this paper, a new automatic rail surface exploring platform with a speed controller has been developed for improving measurement accuracy and reducing inconsistency of measurements. In addition, we propose a data integration method of the rail surface roughness with multiple homogeneous displacement sensors and verified the accuracy of the integrated data through standard test-bed railway track investigation.

• The KIPS Transactions:PartD
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• v.16D no.3
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• pp.433-440
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• 2009

As information technology of constructional area develops recently, web-based on-line system is rapidly increasing to provide information on diverse constructional materials so as to enhance productivity of constructional business and to reduce cost. Since the constructional materials information provided by these systems, i.e., quality, specification, etc are not standardized, however, the staffs on the constructional site suffer considerable difficulties in using materials information when acquiring information on specific materials, e.g., using diverse information systems or repeating similar jobs. Thus, this research typified information items of constructional materials on the basis of GDAS and designed multi system model to control integrated information on constructional materials. This system can efficiently control and utilize materials information by supporting automatic classification of constructional materials to which OmniClass Part-22 and UNSPSC are applied, conditional complex retrieval of materials information, real-time automatic embodiment of electronic catalog and retrieving/controlling RFID.