• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.4
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• pp.409-417
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• 2009

Nowadays, the construction sites are growing in city every year, so complaints for construction noise have increased more and more. To analyze this noise scientifically, construction noise prediction program was developed in 1998 and 2005 but it is too difficult to apply program in field because there is few soundproof facilities and it can't understand the coordinate system and so on. The aim of this study is to develop noise prediction program to apply in construction sites. For this, the problems of existing program was analyzed and survey was performed to get requestion of field overseer and upgraded program. To get reliability of program, it was compared with sound measurement value in field. As a result, construction sound prediction program have various soundproof facilities data than existing program. It can also analyze multi receiver point at the same time for several construction machinery. Most of all, it is more powerful to set receiver or source in the axis of X, Y, Z. so program user can make use of it easily. An average of difference is -0.9~1.8 dB.

• Korean Journal of Construction Engineering and Management
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• v.3 no.1 s.9
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• pp.107-114
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• 2002

Recently, a few major construction companies in Korea have a growing interests to the risk management system, and they are trying to apply it to their construction projects. However, the existing methodologies to be applied to the foreign public projects are not proper to the construction environments due to its adaptabilities, that has one time process and heavily depends on personal judgement. The purpose of this paper is to propose a risk response process in consideration of the residual risks, which would be more adaptable and practical in the construction environment, overcoming the current obstacles to be mentioned above. This process has systematic repeat process until the residual risks go down to the risk thresholds based on the efficiency of specific response strategy.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.427-430
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• 2006

Recently, it is necessary that construction industry should be into high value-added business lines using the measurement system because construction projects are increasing their complexity, variety and scale. But Performance measurement Systems that are most used around the world are subject to limitations for application on internal construction industry. This study addresses limitations of measurement system that is existing and proposes methodology for development of efficient Success Index system based on Critical Success Factors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1782-1788
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• 2015

In this paper, analysis of the effects for construction tolerances on the current collection performance of high speed catenary system. The height of the contact wire is the geometrical position of the cantilever directly affects the current collection performance. Contact force when the height of the contact wire exceeds the construction tolerance were analyzed. As a result, the maximum contact force was analyzed to more than 350[N] that are recommended by EN50119. And when the geometrical position of the cantilever to exceeds the construction tolerance, the analysis results of uplift at the mast support points, it becomes 127[mm] that are recommended by UIC 799. If the construction tolerances exceeds the reference value, the current collection performance is deteriorated. Therefore, catenary system require high precision construction. In the future, there is a need for continuing research on the tolerance of catenary system in the actual operating state.

• Korean Journal of Construction Engineering and Management
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• v.17 no.1
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• pp.40-47
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• 2016

Recently, the demand of sewage treatment facilities have increased by growing the population growth of city and industrialization. However, most of public sewage treatment facilities lack the preparations of design criteria by increasing sewage water amount in the future. In order to respond to this situation, the government has consistently promoted the sewage treatment construction project. This study conducted a survey targeting residents and sewage treatment facilities, civil engineering a VE project professionals for effectively operating the sewage treatment facilities and improving its value to be built in the future. Based on this survey, this study will introduce the list of performance measurements which can not only save cost but also reflect opinion of users and residents. In addition, using Multi-Level Performance Measurement and AHP analyzed the weights of performance measurement which is more objective than existing things for applying efficient VE process

• International conference on construction engineering and project management
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• 2015.10a
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• pp.691-692
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• 2015

Several scholars in South Korea have predicted that maintenance costs of social infrastructure will sharply increase from the mid-2020s, and cause budgetary deficits among facilities management agencies. Interest in infrastructure asset management (IAM) is rising as a solution to such problem. In this study, an information system for asset valuation that reflects the salvage value and deferred cost of social infrastructure based on WBS (work breakdown structure) was developed in consideration of IAM. To reuse the construction cost information such as the acquisition cost, the interconnection between CBS (cost breakdown structure) and WBS was considered. Furthermore, asset valuation information was developed with XML schema to facilitate the exchange and reuse of the information among project participants.

• Geomechanics and Engineering
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• v.19 no.4
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• pp.307-314
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• 2019

Light construction waste (LCW) particles are pieces of light concrete or insulation wall with light quality and certain strength, containing rich isolated and disconnected pores. Mixing LCW particles with soil can be one of the alternative lightweight soils. It can lighten and stabilize the deep-thick soft soil in-situ. In this study, the unconfined compressive strength (UCS) and its mechanism of Construction Waste Stabilized Lightweight Soil (CWSLS) are investigated. According to the prescription design, totally 35 sets of specimens are tested for the index of dry density (DD) and unconfined compressive strength (UCS). The results show that the DD of CWSLS is mainly affected by LCW content, and it decreases obviously with the increase of LCW content, while increases slightly with the increase of cement content. The UCS of CWSLS first increases and then decreases with the increase of LCW content, existing a peak value. The UCS increases linearly with the increase of cement content, while the strength growth rate is dramatically affected by the different LCW contents. The UCS of CWSLS mainly comes from the skeleton impaction of LCW particles and the gelation of soil-cement composite slurry. According to the distribution of LCW particles and soil-cement composite slurry, CWSLS specimens are divided into three structures: "suspend-dense" structure, "framework-dense" structure and "framework-pore" structure.

• Nuclear Engineering and Technology
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• v.42 no.4
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• pp.460-467
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• 2010

In this study, the parameters of the feedwater control system (FWCS) of the OPR1000 type nuclear power plant (NPP) are optimized by response surface methodology (RSM) in order to acquire better level control performance from the FWCS. The objective of the optimization is to minimize the steam generator (SG) water level deviation from the reference level during transients. The objective functions for this optimization are relationships between the SG level deviation and the parameters of the FWCS. However, in this case of FWCS parameter optimization, the objective functions are not available in the form of analytic equations and the responses (the SG level at plant transients) to inputs (FWCS parameters) can be evaluated by computer simulations only. Classical optimization methods cannot be used because the objective function value cannot be calculated directely. Therefore, the simulation optimization methodology is used and the RSM is adopted as the simulation optimization algorithm. Objective functions are evaluated with several typical transients in NPPs using a system simulation computer code that has been utilized for the system performance analysis of actual NPPs. The results show that the optimized parameters have better SG level control performance. The degree of the SG level deviation from the reference level during transients is minimized and consequently the control performance of the FWCS is remarkably improved.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.784-791
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• 2022

Tack coat is a thin layer of asphalt between the existing pavement and asphalt overlay. During construction, insufficient tack coat layering can later cause surface defects such as slippage, shoving, and rutting. This paper proposed a method for tack coat inspection improvement using an unmanned aerial vehicle (UAV) and deep learning neural network for automatic non-uniform assessment of the applied tack coat area. In this method, the drone-captured images are exploited for assessment using a combination of Mask R-CNN and Grey Level Co-occurrence Matrix (GLCM). Mask R-CNN is utilized to detect the tack coat region and segment the region of interest from the surroundings. GLCM is used to analyze the texture of the segmented region and measure the uniformity and non-uniformity of the tack coat on the existing pavements. The results of the field experiment showed both the intersection over union of Mask R-CNN and the non-uniformity measured by GLCM were promising with respect to their accuracy. The proposed method is automatic and cost-efficient, which would be of value to state Departments of Transportation for better management of their work in pavement construction and rehabilitation.

• Korean Journal of Construction Engineering and Management
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• v.19 no.2
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• pp.3-14
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• 2018

The system to appraise the execution capabilities of construction companies had been began as the Construction Contract Restriction System in 1958, was changed as the Construction Subcontract Restriction System in 1961, and finally has been operated as the Appraisal and Public Announcement of Execution Capacity (APAEC) from 1996. The APAEC system has been utilized as a firm and unique tool for assessing the execution capacities of construction companies despite many problems and continuous system changes. In spite of numerous studies to improve the APAEC system, however, efforts to analyze the system from the empirical point of view were insufficient. In this study, we analyze the status of APAEC system through analyzing correlations among assessment results of the APAEC, earned values of construction works, construction management performance indexes, and macroeconomic indexes for the past 10 years from 2007 to 2016. As a result of the analysis, it was found that Appraisal Value of Execution Capacity (AVEC) is excessively inflated in engineering and landscaping areas compared to Earned Value of Construction Work (EVCW) and the correlations between the AVECs and EVECs are not high in the areas of engineering, industrial equipment, and landscaping. In addition, technical appraisal values are excessively inflated in engineering and landscaping areas and correlations between AVEC and its components are high in the areas of engineering & building, industrial equipment, and large companies, but low in the areas of engineering, building, landscaping, and small and medium companies. Finally, the concentration of the AVEC is intensifying more and more and the concentration deteriorates construction management performance indexes and macroeconomic indexes. If we continuously improve the APAEC system based on the implications derived in this study, the APAEC system will be able to maintain it's position of a firm and unique means to access the execution capacities of construction companies.