• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.133-138
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• 2010

Conceptual cost is estimated with insufficient information at an early stage of a building construction project, resulting in an inevitable gap between conceptual estimated cost and real constructed cost. For a project to be successful, this gap must be managed to be lower than a reliable level. Therefore, the purpose of this study is to propose a structural process for managing the reliability of conceptual cost estimates at an early stage of a building construction project. In researching this study, conceptual cost estimate experts were interviewed,and a risk management process was studied. Reliability assessment and a review process for improving the quality of conceptual cost estimate and the planning strategy of reliability management based on previous similar projects were added to the present estimate process. The proposed reliability management process will improve the chances of a successful project, by helping to decrease the risk of conceptual estimated cost.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.937-942
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• 2005

It is necessary to estimate the runoff hydrograph and peak flood discharge using law of probability for synthetic flood control policy and design of hydraulic structures. Rainfall analysis is needed in the process of peak flood discharge estimation and the time distribution of a design rainfall is a very important process in the analysis. In this study, we estimate design flood for a small urban basin and a rural basin of medium scale which have different travel times. The Huff method is widely used in Korea for the time distribution of design rainfall to estimate design flood. So, we use Huff method and a conceptual method which is suggested in this study for the comparative purpose. The 100-year frequency rainfall is used to estimate design flood for each basin and the design flood is compared with the existing design flood. As the result, the design flood is overestimated $14.6m^3/sec$ by Huff method and is underestimated $70.9m^3/sec$ by a conceptual method for the rural basin. For the small urban basin, the design flood is excessively overestimated $294.65m^3/sec$ by Huff method and is overestimated $173m^3/sec$ by a conceptual method. The reason of excessive overestimation by Huff method in the small urban basin is that the increased rate of rainfall intensity according to the decrease of duration is large and the duration exceeds the time of concentration when the increased rainfall intensity is concentrated in a quartile. Therefore, we suggested a conceptual method for the time distribution of design rainfall by considering the rainless period and duration. Especially, the conceptual method might be useful for the small urban basin with short concentration time which the design flood is overestimated by Huff method.

• Journal of the Korea Institute of Building Construction
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• v.20 no.2
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• pp.147-153
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• 2020

It is important to estimate the optimal construction cost at the early stage of the project. In this regard, conceptual cost estimate is an important factor for estimate optimal construction cost. However, domestic conceptual cost estimate are only used as cost per unit area according to the building type, and it's accuracy is not high. Hence, the purpose of this study is to calculate the approximate quantity and cost for reinforcing bars, concrete, and formwork by presenting a regression formula based on the total floor area of the common work items in the frame work. In order to verify the accuracy and validity of the regression formula presented in this study, a comparative analysis was performed by applying the regression formula and the traditional approximate quantity take-off method to real cases. As a result, the estimated error rate of the traditional method was -102~+55%, and exceeded the estimated conceptual cost estimate accuracy range of -50~+100% suggested by AACE(American Association of Cost Engineering). On the other hand, the error rate of the regression formula method presented in this study was -6.4~+11.62%. This can be used not only for conceptual cost estimate range of accuracy, but also for detailed estimates. However, it is necessary to analyze the factors that affect the unit price as well as quantity in order to calculate the appropriate cost.

• Korean Journal of Construction Engineering and Management
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• v.7 no.4 s.32
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• pp.91-99
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• 2006

The purpose of this study is propose an Artificial Neural Network(ANN) model for the construction estimate of the public educational facility at conceptual stage. The current method for the preliminary cost estimate of the public educational facility uses a single-parameter which is based on basic criteria such as a gross floor area. However, its accuracy is low due to the nature of the method. When the difference between the conceptual estimate and detailed estimate is huge, the project has to be modified to meet the established budget. Thus, the ANN model is developed by using multi-parameters in order to estimate the project budget cost more accurately. The result of the research shows 6.82% of the testing error rates when the developed model was tested. The error rates and the error range of the developed model are smaller than those of the general preliminary estimating model at conceptual stage. Since the proposed ANN model was trained using the detailed estimate information of the past 5 years' school construction data, it is expected to forecast the school project cost accurately.

• Journal of the Korea Institute of Building Construction
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• v.21 no.5
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• pp.495-506
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• 2021

A Conceptual cost estimate, which is computed in the preliminary step of a project, is important for decision-making by a contractor in terms of the project budget, economic feasibility and validity analysis, and alternative comparisons. Therefore, a high error rate of a prediction model for a conceptual cost estimate can lead to various problems including excessive project expenditures and a delayed break-even point. this study proposed optimal impact factors by configuring quantitative impact factors computable in a preliminary step in various cases(combinations of impact factors). subsequently, the accuracy of different cases was comparatively analyzed by using the cases as input values of a prediction model using regression analysis. when the optimal combination of impact factors proposed in this study and other combination of impact factors were applied to the prediction model, the regression analysis-based prediction model exhibited 0.2-4.7% improvements in accuracy, respectively. the optimal combination of impact factors proposed in this study improved the accuracy of the prediction model of a conceptual cost estimate by removing unnecessary impact factor.

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.53-59
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• 2008

Cost estimates are very important to their decision-making in the early stages of a construction project. So Clients have wanted not only to know the results of conceptual cost estimates but also to assess their quality Conceptual cost estimates process is very complex process, so the results of cost estimates are influenced by various factors. So the purpose of this study is to reveal the key factors which influence the reliability of conceptual cost estimates in building construction projects. The analytic hierarchy process is used to determine the relative important weights of elements influencing the conceptual cost estimates. And factor analysis is used to reveal the key factors from the elements that influence the conceptual cost estimates. The results showed that the key factors is an experience level, available data level, level of will for winning the bid, difficulty level of conceptual cost estimate, uncertainty level.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1595-1600
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• 2007

It is necessary a simple helicopter design and performance analysis program for a stage of helicopter conceptual design. To meet that needs, we have developed a program which is simply used to estimate helicopter configuration and performance. The program developed by this study is composed of Requirement, Mission profile Analysis, Size, Aerodynamic, Trim, Propulsion, Weight, and Performance modules, and each modules carry out operations for a given flight condition. In this study, we validate this analysis program in 9,500 1bs and 22,000 1bs helicopters and estimate design configuration and performance of 16,000 1b helicopter. And We can use this program to optimization process for Helicopter MDO framework.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.194-202
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• 2011

Most of Orders of Magnitude estimate are based on historical data. This data is converted to the current price using by the cost index method mainly. This method, however, is rarely utilized or only for one-time use due to the lack of data and the complex escalation calculation method. This paper present a typical process on the conceptual investment cost estimation using by Cost Indexes based on the actual case for the Train Control facility of High-speed rail project. The result is expected to serve as both an easy way for Order of Magnitude estimate and a standard guideline for computerized modeling.

• Ocean Systems Engineering
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• v.10 no.1
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• pp.111-129
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• 2020

A simplified algorithm is proposed for fast estimation of the material quantities required for the construction of rubble-mound breakwaters. The proposed algorithm is able to employ only the data available at feasibility study phase such as the maximum draught of the design ship selected to transport the cargos to the harbor despite, because at the feasibility phase, information for the planned harbor is likely to be very limited. A linear-constant waterdepth model together with a proposed section configuration for the breakwaters, which is customary for harbors, is considered to calculate the quantity of materials. The numerical simulation of the wave characteristics has been verified using the recorded wave data collected by a buoy installed near the Neka harbor in Caspian Sea waters. A case study has been also applied to four harbors to validate the proposed algorithm. The estimated weights using the proposed linear-constant and multi-linear waterdepth models were compared using the bathymetry maps and layouts of these harbors. A computer program, written in QBasic language, has been developed to simulate the wave characteristics and to estimate the material quantities needed to construct a rubble-mound breakwater. The obtained results show that taking into account the acceptable accuracies normally applied to the feasibility study and conceptual design phases, the proposed algorithm is sufficiently accurate and highly effective for the conceptual estimation of materials' quantities of breakwaters in the feasibility study phase of harbor projects.

• Asia Marketing Journal
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• v.13 no.4
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• pp.29-54
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• 2012

Recently, as film has been admitted as the artistic merit and higher value-added business, the past studies on film have been lively carried on various fields. Especially, the film business is thought to be value-added business and has explored the causes of influencing spectators. However, there are no researches enough to explain what induces the choice and diffusion of the film. The film is not only hedonic products but also typical example of experiential products. So how to process film formation plays important roles in explaining the procedures of forming preference on the film and the movies spread more widely. But the great part of study of films has been concentrated on exploring hedonic factors of influencing spectator's choice. Until now there is not enough study for the relationship between experiential information processing and film preference. To explain film's preference, our study focuses on preference fluency and processing fluency that can provide an insight for our question about the relationship. In this article, to explain the procedures of processing experiential information and forming preference on the film, our study focuses on finding the relationship between film's processing fluency and film's preference fluency and explores the factors that affect film's processing fluency. To achieve the goal of this study, we distinguish factors of film's conceptual fluency from factors of film's perceptual fluency and explore the paths from the factors to film's preference fluency. The factors which have effects on perceptual fluency are hypothesized to be distinction of image expression, distinction of sound expression, correspondence between actors' image and their role. The factors which have effect on conceptual fluency are supposed to be well-organized story, suitability of lines expression. The experiments in which students were sampled at 'C' university were conducted in 2010 (december). Data collection was proceeded through questionnaires. We test the hypothesized model by using structural equation modeling(Amos 17.0). The fit indices for the model are as follows : x²=416.266(df=213, p=0.00), GFI=0.855, AGFI=0.812, RMSEA =0.069, IFI=O.925, CFI=0.920, TLI=0.905. According to the guidelines, there is evidence that our measurement model fits data. The results of empirical study are as follows. The path from film's perceptual fluency to film's preference fluency is supported(estimate: 0.223, C.R: 2.641). The path from film's conceptual fluency to film's preference fluency is supported(estimate: 0.397, C.R: 4.863). The path from distinction of image expression to film's perceptual fluency is not supported(estimate: 0.113, C.R: 1.665). The path from distinction of sound expression to film's perceptual fluency is supported (estimate: 0.190, C.R: 2.042). The path from correspondence between actors' image and their role to film's perceptual fluency is supported(estimate: 0.686, C.R: 5.566). The path from well-organized story to film's conceptual fluency is supported(estimate: 0.396, C.R: 4.023). The path from suitability of lines expression to film's conceptual fluency is supported(estimate: 0.536, C.R: 5.441). Concludingly, our study explored the influencing factors of film's processing fluency inducing film's Preference fluency. First, film's perceptual fluency and film's conceptual fluency have positive effects on film's preference fluency. Second, distinction of image expression is not significant on film's perceptual fluency, but distinction of sound expression and image's correspondence of actors' image and their role have positive effects on film's perceptual fluency. Lastly, well-organized story and suitability of lines expression have positive effects on film's conceptual fluency.