• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.504-509
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• 2012

Automotive suspension mat is installed at seat back frame. As the back part of passenger is aupported by suspension mat, it is prevented from the pressure concentration. The tired feeling at driving is minimized and the comfortable feeling is increased. In this study, vibration and fatigue are analyzed with plastic suspension mat modelled by 3 Dimension. By the analysis result, the natural frequency becomes 30 Hz with life of $10^6$ cycle and safety factor of 1.6055. Development time and evaluation cost can be cut down by utilizing this analytical technique.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.77-87
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• 2015

PURPOSES: It is theoretically well known all over the world, that porous hot mixed asphalt (HMA) with hydrated Lime improves moisture and rutting resistance, and reduces pothole occurrence frequency, as well as the life cycle cost (LCC). METHODS : Addictive in the two different formations of the liquid anti-stripping Agent and powder Hydrated-Lime was applied in this investigation in order to obtain relatively clear results according to their types and conditions. Firstly, the moisture conditions were set, and applied to the porous HMA mixtures with hydrated lime (anti-stripping agent). Next, it was followed by a non-destructive test with the application of three freeze-thaw cycles, which were individually carried out thrice to compare the results of the dynamic moduli. Lastly, the hydrated lime effect related to moisture sensibility to porous HMA has been verified through the analysis of the modulus results regarding the change rate of dynamic modulus per n-cycle. RESULTS: It is clear from this investigation, that the dynamic modulus is inversely proportional to the change in temperature, as the graph representing the rigidity of the thermorheologically simple (TRS) material showed gradual decline of the dynamic modulus with the increase in temperature. CONCLUSIONS: The porous HMA mixture with the anti-stripping agent (hydrated Lime) has been found to be more moisture resistant to freezing and thawing than the normal porous HMA mixture. It is clear that the hydrated lime helps the HMA mixture to improve its fatigue resistance.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.7-18
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• 2005

Over the past twenty years, the maintenance system has been developed and its importance has been increased. For the effective maintenance of the urban transit, we have developed the maintenance system based on the concept of RCM(Reliability Centered Maintenance). RCM analysis is a systematic approach to developing a cost-effective maintenance strategy based on the various components's reliability of the system in question. It is performed according to process that includes the following steps; definition of function and functional failures of the systems, construction of RB D(Reliability Block Diagram), performance of FMEA(Failure Modes & Effects Analysis) and calculation of the reliability index. The final process of RCM is to determine appropriate failure maintenance strategies. This paper aims to define the procedure of maintenace based on the concept of RCM for urban transit. The key for a successful maintenance system is an automated scheduling to the maximum extent possible and timely executions. The developed system issues maintenance plan and repair request based on analyzed data and maintenance experience.

• Korean Journal of Construction Engineering and Management
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• v.7 no.6
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• pp.121-131
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• 2006

Since "Act on Private Participation in Infrastructure" were changed in January 2005, BTL(Build-Transfer-Lease) projects of Private Participation In Infrastructure was introduced in the domestic construction market for the purpose of providing public facilities with the public. Selecting the most qualified Promoter should be considered discreetly in BTL projects because BTL projects is for projects with approximately thirty year project life cycle, plan, construction, operating, maintenance and obviously the success of the project totally depends on the capability and role of concessionaire. However, score for cost is likely to influence designating concessionaire to take the project. Accordingly, low bid contract with too much competition could decrease the quality of the construction plan and operating plan. Thus, this study did preliminary research and documents on problems of evaluation criteria for designating concessionaire in BTL projects, and proposed improvement program by doing questionnaire over specialists of each field.

• The Journal of Sustainable Design and Educational Environment Research
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• v.21 no.2
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• pp.1-10
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• 2022

This study aims to prepare an objective project basis by reviewing the feasibility of reconstructing and remodeling Greensmart Future School project for S High School's main building, which was built more than 40 years ago, in Incheon Metropolitan City, and to apply and review an effective methodology for determining renovation and remodeling. To this end, the feasibility of reconstruction and remodeling was evaluated in the long term by synthesizing the results of quantitative evaluation through economic review and qualitative evaluation through educational functional review. As a result of the study, it was found that the reconstruction plan was advantageous throughout all alternatives in terms of economic costs, and the field survey indicated limitations in spatial functions to support students' various educational activities and applying new directions, especially the 2022 revised curriculum and high school credit system.

• Korean Journal of Construction Engineering and Management
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• v.12 no.3
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• pp.91-100
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• 2011

Green technologies of buildings are spreading for saving resource and energy consumption during life cycle of buildings. However, selection of optimized the technologies for applying projects is needed a lot of time and costs. Therefore prioritization is necessary to apply the technologies for buildings. An evaluation of economic value for the technologies is significant for prioritization of the technologies, however, the current evaluation system of economic value for technologies is not reflected the accurate features of the technologies. Green technologies have the objectives for reducing the emission of CO2 and saving the cost during the whole lifecycle of buildings. Thus the evaluation of economic feasibility for green technologies is needed to include the economic value from improving the environment. This paper developed the economic evaluation method integrated with LCC and LCA to accurately analyze the economic value for green technologies. Moreover, this paper drew the priority of the technologies by conducting case studies with the integrated method and analyzing the results with AHP. The conclusion of case studies, Green technologies is worth more if to include the economic value from improving the environment. Then in analysis of priority, Green intelligent component technologies were rated the highest. The conclusion of the study is able to utilize the supporting tool for making decision to select the optimized technologies for the projects and precedence study for developing future research of prioritization for green technologies. The future study for improving the developed method will supplement the various evaluation factors and apply the detailed weight to analyze the priority of green technologies.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.119-129
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• 2009

Building construction trends have been changed dramatically in terms of size and mass. With the need to maximize land usage, there has been an increase in the construction of high-rise buildings. This affects not only the entire construction duration and cost, but also subsequent construction activities, such as work to increase underground facilities and in reclamation land area construction. These types of site conditions require soft ground reinforcement and the proper uplift water pressure treatment. In general, two kinds of methods have been used for uplift water pressure treatment systems. However, there have been some problems arising as the result of a lack of research and analysis on underground construction techniques, and a reliance on experiments over actual survey and analysis of site conditions. This paper focused on the problems of conventional selection procedure, by analyzing drawings and proposing a kind of modeling for a reasonable procedure. The results were applied to OO project as a sample construction case to be verified in this research. The initial plan in the case project was the Rock Anchor System. However, as there were terrible miscalculations of basic site conditions that had an extraordinary influence on the underground water level, such as the site's proximity to the Han-river, it was necessary to change the plan to include apermanent drainage system. This achieved a direct construction cost reduction \ 406,702,000 and a maximum sayings of 4% of operational cost, based on the 50-year building Life Cycle Cost.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.365-370
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• 2012

In this study, Economic analysis of supercritical coal-fired power plant with $CO_2$ capture process was performed. For this purpose, chemical absorption method using amine solvent, which is commercially available and most suitable for existing thermal power plant, was studied. For the evaluation of the economic analysis of coal-fired power plant with post-combustion $CO_2$ capture process in Korea, energy penalty after $CO_2$ capture was calculated using the power equivalent factor suggested by Bolland et al. And the overnight cost of power plant (or cost of plant construction) and the operation cost reported by the IEA (International Energy Agency) were used. Based on chemical absorption method using a amine solvent and 3.31 GJ/$tonCO_2$ as a regeneration energy in the stripper, the net power efficiency was reduced from 41.0% (without $CO_2$ capture) to 31.6% (with $CO_2$ capture) and the levelized cost of electricity was increased from 45.5 USD/MWh (Reference case, without $CO_2$ capture) to 73.9 USD/MWh (With $CO_2$ capture) and the cost of $CO_2$ avoided was estimated as 41.3 USD/$tonCO_2$.

• Korean Journal of Construction Engineering and Management
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• v.17 no.5
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• pp.120-129
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• 2016

The user cost is an important analysis item which should be considered together with life-cycle of facility, administrator cost and discount rate in LCCA for efficient asset management of SOC facilities. Especially, a significant delay cost occurs often for users in the road field due to a work zone for cleaning and maintenance, and in such case, the administrator should consider the administrator cost as well as the user cost for more rational decision making. However, the user cost has not been considered in most decision making steps until recently and relevant studies also have not been carried out actively. In this study, the methodology to estimate the user cost and delay cost required in the decision making step using the traffic flow model and the direct benefit estimation model in the traffic facility investment evaluation guideline is suggested. And, the traffic flow model was estimated on 4 national highway sections where maintenance was actually carried out in 2014 using VISSIM and, the user cost and the delay cost were estimated based on the suggested methodology. The analysis result showed that the average user cost of $17,569,000KRW/km{\times}day$ occurred on Section A with approximately 30,000 AADT before a work zone occurred, and in case the first lane was blocked for maintenance, the delay cost of $10,193,000KRW/km{\times}day$ (158%) on average occurred additionally. The delay cost of $1,507,000KRW/km{\times}day$ (115%) and $1,985,000KRW/km{\times}day$ (119%) occurred on Sections B and D with approximately 20,000 AADT respectively and the delay cost of $262,000KRW/km{\times}day$ (105%) occurred on Section C with approximately 10,000 AADT. This result of this study was estimated based on the simulation of traffic flow model so that there is a limitation in its actual application. A study ot develop a highly appropriate model using actual observation data and improve the possibility to apply it through the verification using the simulation will be necessary in future.

• Korean Journal of Construction Engineering and Management
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• v.10 no.1
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• pp.114-125
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• 2009

In this study, a design value analysis technique that considered stochastic LCC and stochastic performance evaluation was proposed, and by introducing the concept of reliability analysis, a decision making that secured reliability was supported. The results of this study, which was carried out according to the above objectives and methods, are summarized as follows: 1) The design value analysis procedures and value state function, improved in order to carry out a reliable analysis when evaluating alternate proposals that were extracted after the function definition was complete, were formalized, and in order to secure consistency and efficiency for value evaluation procedures, an evaluation index scheme was proposed; 2) Database collection and analysis were done for a bridge's LCC analysis. As for the collection scope of data, literature of previous research done on a bridge's LCC analysis was used as the basis for analysis, and for securing reliability regarding analysis results and dealing with uncertainty of collected data, the MCS technique was applied; 3) Weights and evaluation ranks for performance evaluation of each of the alternate proposals, as well as LCC analysis model, analysis period, discount rate, user expense, safety inspection and safety diagnosis expense conditions for LCC analysis were proposed. Lastly, a feasibility study was done and conclusion was made about "OO grand bridge and connecting road construction work execution design" project centered on value analysis execution case.