• International conference on construction engineering and project management
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• 2011.02a
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• pp.7-11
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• 2011

Quantity take-off (QT) is one of the most important tasks for determining the total cost of a construction project, and it requires accuracy and reliability for the result. Accuracy and reliability in BIM-based QT are also required to assure the completeness of the result. However, there has been no basis to measure the completeness of the BIM-based QT result. As BIM is increasingly being adopted in the construction industry with a wide variety of purposes, it becomes more important to have a method to improve the completeness of BIM-based QT and criteria to measure it. This research focuses on the hypothesis that the completeness of BIM-based QT relies on the accuracy and reliability of BIM and the BIM-based QT process. As a basic research to determine the completeness of BIM-based QT, this research analyzes and derives factors that affect the completeness of BIM-based QT.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.4
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• pp.94-100
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• 1999

Stone is one of the oldest material for construction and artistic works. This study investigates the current use of stones in landscape constructional works, and the design criteria to advance the arts of natural stone arrangements. Thirty four experts and thirty two others were surveyed with various photos of simulated construction works of natural stone arrangements fond improved design guidelines. Major findings are as follows: -The payment for the use of stones ranges approximately 5 to 10% of total cost of landscape constructional works. More stones may be used when better retailing system is introduced, working skill is standardized, and more of the substitute natural stones made of blasted rocks are provided and the cost goes down. -Preferences showed little difference for the mixed use of different sizes, colors and shapes of stones, and for the use of similar ones, in the construction of walls. This does not match with the current design guidelines. -Arranging three stones, which symbolizes heaven, earth, and human being, was the most preferred. As the supply of natural stones is limited and more substitute stones are used, it its needed to establish guidelines for the production of substitute stones. -Grasses are much more preferred between pavement stones than mortars. -In current practices, top of piled up natural stones is usually arranged level. More freely curved top lines are preferred to straight line.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.69-78
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• 2007

In real world, the project managers handle conflicting goals that govern the use of resources within the stipulated time and budget with required quality and safety. These conflicting goals are required to be optimized simultaneously by the project managers in the framework of fuzzy aspiration levels. The fuzzy linear programming model proposed herein helps project managers to minimize total project costs, completion time, and crashing costs considering indirect costs, contractual penalty costs etc by practically charging them in terms of direct cost of the project. A case study of bituminous pavement under construction is considered to demonstrate the feasibility of applying the proposed model for optimization of project parameters. Consequently, the proposed model yields an efficient compromise solution and the decision maker's overall degree of satisfaction with multiple fuzzy goal values. Additionally, the proposed model provides a systematic decision-making framework, enabling decision maker to interactively modify the fuzzy data and model parameters until a satisfactory solution is obtained. The significant characteristics that differentiate the proposed model with other models include, flexible decision-making process, multiple objective functions, and wide-ranging decision information.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1189-1194
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• 2009

A gutter-shaped U grating is a facility that is installed at the sides of a road to provide pedestrians with a rainwater-free road. The previous studies on this facility focused mainly on the progress of the efforts that are being made to improve its performance and interception efficiency so as to prevent damages in regional areas due to the heavy rains caused by climate change. The studies on its maintenance, however, are still inadequate. Therefore, this study was conducted to analyze and compare the life cycle costs and performance evaluations of the steel and magic gratings, which are installed in apartments. The results of the study show that the replacement period and rate of gratings differ depending on where they are installed. The initial capital investment cost of a magic grating installed at a road where many vehicles pass is quite high, but in terms of its maintenance and entire-life-cycle costs, its total expenses are lower than those of a steel grating. The results of this study are expected to serve as preliminary data for the selection of an adequate grating that is suitable for particular places in the design phase of construction projects.

• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.62-69
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• 2005

The optimal design of transmission system expansion planning is an important part of the overall planning task of electric power system under competitive electricity market environments. One of main keys of the successful grid expansion planning comes from optimal reliability level/criteria decision, which should be given for constraint in the optimal expansion problem. However, it's very difficult to decide logically the optimal reliability criteria of a transmission system as well as generation system expansion planning in a society. This paper approaches a methodology for deciding the optimal reliability criteria for an optimal transmission system expansion planning. A deterministic reliability criteria, BRR (Bus Reserve Rate) is used in this study. The optimal reliability criteria, BRR/sup */, is decided at minimum cost point of total cost curve which is the sum of the utility cost associated with construction cost and the customer outage cost associated with supply interruptions for load considering bus reserve rate at load buses in long term forecasting. The characteristics and effectiveness of this methodology are illustrated by the case study using IEEE-RTS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3D
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• pp.373-379
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• 2009

Cost estimation in the early phase enables government to plan public budgeting more efficiently by providing information about construction cost. However, cost estimation in the early phase is difficult to predict because only a little information can be utilized. The cost estimation method now being used by the government is calculated by length of the road multiplied by unit cost per length and shows high error rate because it cannot reflect the unique characteristics of each project. As the project is being proceeded, level of available information also changed. So, reflecting available information of a project is important. This paper divided early phase into two parts : planning phase and early design phase, and developed cost estimation model considering level of available information of each phase. Total 143 cases are utilized to find influencing variables and develop cost estimation model and model validation is done by adopting required accuracy level. This cost estimation model reflecting level of available information can be applied to public budgeting, feasibility test, and comparison between routes.

• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.87-96
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• 2004

The construction duration in apartment construction is an important factor which affects project cost. Henceforth, the time shortening is essential to retrench project cost and project risk when there adopt Five-Day Workweek and introduce apartment sales after completion of construction. Therefore, the purpose of this study is to examine closely the affecting factors on the duration of framework which forms about $40\sim50\$ percent of total time in apartment construction by analyzing the schedule mechanism of typical floor and to show the reasonable time shortening methods by case study. The shown schedule mechanism and basic schedule table can utilize as a guideline in case of scheduling of framework in the existing construction method. Also, the shown time shortening methods by three case studies will guide the direction and process of time shortening while there need time shortening in many-sided projects.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.21-28
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• 2006

Changes in building construction methods and repairing of older buildings have reduced infiltration rate. Synthetic materials, release airborne particles and uneven healthy odor are increased. For preventing pollutants introduce fresh outdoor air into the building, simply letting fresh outdoor air into building, however, Is not a cost-effective way to ventilation. When additional ventilation is added to an existing HVAC system, the heating and cooling equipment, often cannot handle the increased load. A HRV provides a way to minimize in energy costs while introducing fresh air to a building. In this study, the economical research of HRV, made of three types of materials, are conducted. Heat recovering characteristics are studied at seasonal outdoor air conditions based on the outdoor air property condition at, Seoul in 2002. As a results, the average sensible effectiveness is 0.75 in the sensible heat exchanger and average total effectiveness is 0.65 in the total heat exchanger. The pay back period of the sensible heat exchangers are $3.2{\sim}3.5$ year and it of total heat exchanger is 2.2 years.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.407-415
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• 2015

The railway route and alignment planning have been executed with a limited number of alternatives based on the site pre-survey and the topographic map. This study developed an intelligent railway alignment planning program (ei-Rail) which can derive all the considerable design alternatives and provide the data for the alternative evaluation such as constructions cost, operation cost, and etc. According to the comparisons with prevailing planned railway projects, the time and cost for planning can be reduced as well as the construction costs. This program may contribute to the development of railway industry by reducing the time and cost for planning as well as the total project cost.

• Korean Journal of Construction Engineering and Management
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• v.25 no.5
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• pp.73-81
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• 2024

In South Korea, NO_X emissions are a major concern, leading to acid rain and smog, harming both the atmosphere and human health, particularly in urban areas. This study seeks to determine the most advantageous pavement material for NO_X reduction in urban areas and assess whether photocatalytic pavement blocks, proven to reduce NO_X emissions, can serve as a viable alternative to conventional cement pavement blocks. To achieve this, a comparative life cycle cost (LCC) analysis was conducted between photocatalytic pavement blocks and conventional cement pavement blocks installed for their NO_X reduction capabilities. The cost-saving benefits of NO_X reduction were monetized for photocatalytic pavement blocks. The analysis period was based on the least common multiple of the replacement cycles of both pavement materials: 30 years. The results revealed that while photocatalytic pavement blocks initially produce higher installation costs than cement pavement blocks, they offer greater cost savings in terms of total cost and net present value due to their NO_X reduction effect over the life cycle. Additionally, the cost-saving effects of photocatalytic pavement blocks are even more pronounced because their replacement period is 5 years longer than that of cement pavement blocks. This study holds significance in performing an LCC analysis of the previously unanalyzed photocatalytic pavement blocks while also demonstrating their potential as substitutes for cement pavement blocks.