• International conference on construction engineering and project management
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• 2009.05a
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• pp.1140-1147
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• 2009

Productivity measurement of construction machinery is a significant issue faced by many contractors especially those involved in earthwork projects. Traditionally, equipment production rate has been estimated using data available in manufacturers' catalogues, results of previous construction projects, or personal experience and assessments of the site personnel. Actual production rates obtained after the completion of a project demonstrate the fact that most of these methods fail to provide accurate results and as a direct consequence, may lead to unrealistic project cost estimations prepared by the contractors. What makes this more critical is that in most cases, inadequate cost estimations lead the entire project to exceed the initial budget or fall behind the schedule. In this paper, a linear regression method to estimate bulldozer productivity is introduced. This method has been developed using SPSS-16 software package. The presented method is used to estimate the productivity of Komatsu D-155A1 series which is commonly used in many earthmoving operations in Iran. The data required for the numerical analysis has been collected from actual site observation and productivity measurement of 60 pieces of D-155A1 series currently being used in several earthmoving projects in Iran. Comparative analysis of the output data of the presented regression method and the existing productivity tables provided by the manufacturer shows that when compared to the actual productivity data collected on the jobsite, a significant increase in accuracy and a remarkable reduction of data variance can be achieved by using the presented regression method.

• Journal of the Korea Institute of Building Construction
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• v.11 no.1
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• pp.91-99
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• 2011

Bayesian network is a form of probabilistic graphical model. It incorporates human reasoning to deal with sparse data availability and to determine the probabilities of uncertain cases. In this research, bayesian network is adopted to model the problem of construction project cost. General information, time, cost, and material, the four main factors dominating the characteristic of construction costs, are incorporated into the model. This research presents verify a model that were conducted to illustrate the functionality and application of a decision support system for predicting the costs. The Markov Chain Monte Carlo (MCMC) method is applied to estimate parameter distributions. Furthermore, it is shown that not all the parameters are normally distributed. In addition, cost estimates based on the Gibbs output is performed. It can enhance the decision the decision-making process.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1694-1714
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• 2007

This study is to estimate economic benefits of Standardization R&D of Urban Rail System. Benefit was to be realized through standardization of main areas such as train vehicle, railway, power system, and signal system. To derive and calculate the quantitative benefit, the sources of economic impact was divided into three dimensions -operational cost savings, import substitution, and safety effects. Economic effect of the standardization was categorized based on a modified BSC model. Economic benefits from time and labor savings are converted into cost savings. Import substitution and investment multiplier effect have a positive impact in addition to cost savings. The estimation of the standardization R&D of Urban Rail System was conservatively estimated 370 billion Won. Cost effectiveness of standardized safety system was conservatively translated into economic benefit in this analysis. This study provides a practical guide to economic evaluation of the various railway R&D projects.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.98-99
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• 2014

Construction equipment cost is critical to estimate the total construction costs, particularly in large and complicated projects. Despite its importance, the construction equipment cost may not reflect the current market value since the equipment database is being updated every 6 years at most. To keep construction equipment cost up to date, it is highly recommended to use the standard market price that is reported each year by the Ministry of Security and Public Administration (MOSPA). However, there is still a gap to adopt the standard market price system for the construction equipment cost computing system. Therefore, this paper suggests an effective way to develop a construction equipment cost estimation system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.175-180
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• 2006

Total conceptual cost estimates and the assessment of the reliability of these estimates are critical in the early stages of a building construction project. The purpose of this study is to propose the method to clients or estimators for improving the reliability of conceptual cost estimates by evaluating the reliability of conceptual cost estimates. The data from 83 building construction projects were collected for this study. The results showed that the proposed method can propose alternatives to clients or estimators for improving the reliability of conceptual cost estimates with the process of evaluation, review and feedback. This process can assist clients in their evaluation of the reliability of the estimated cost and the probability of exceeding the target cost, and in their re-estimation after dealing with the elements that influence the conceptual cost estimate badly.

• East Asian Journal of Business Economics (EAJBE)
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• v.12 no.1
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• pp.35-42
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• 2024

Purpose: A railroad project is a complex system with large construction costs in the initial stage and ongoing operating costs over its lifecycle. Current railroad projects tend to be based on construction options, which leads to huge deficiencies in operating costs. This phenomenon results from a lack of appropriate tools to accurately estimate a railroad project's lifecycle costs. This study attempts to analyze the major components of railroad operating costs and to propose a decision-making system for analyzing the long-term lifecycle costs of railroad projects. Research design, data and methodology: We review the literature and analyze the current status of railroad operating costs in Korea and overseas. Based on previous projects, a framework for project options and operating costs is proposed. The framework is applied to actual railroad projects to demonstrate the validity of the model. Results: Case analysis shows that our framework is comprehensive in analyzing the primary aspects of railroad operating costs and plays an effective role in choosing various railroad project options. This study points out that the railway project operates inefficiently because estimating long-term costs without reflecting specific project options causes many errors. Conclusions: A major contribution of this study is the development of an improved framework for accurately estimating operating costs and providing policymakers and engineering firms with a holistic decision support system. Detailed components in estimating operating costs of the railroad business are discussed. And we present a decision-making tool that policymakers and private businesses can use in planning the railroad business.

• The Journal of Information Systems
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• v.27 no.4
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• pp.149-165
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• 2018

Purpose As Korean economy has been sluggish in recent years, firms' interest in publicly financed projects has increased due to the relatively increasing proportion in the economy. Since 1999, publicly financed projects in Korea need to undergo preliminary feasibility study to evaluate economic efficiency and policy quality if they are larger than a certain scale. The benefits of public projects are one of the most important factors in the preliminary feasibility study but are difficult to estimate due to their nature. Design/methodology/approach This study estimates the benefits of the agricultural soil information database, a public database in Korea. The method used in the study is the stated preference method which is formally used in Korea's preliminary feasibility study. Data are collected through surveys and a logit model is constructed to be estimated by the maximum likelihood estimation method. Findings As the first study evaluating a public database, this study can be used as a baseline in all public database projects developed in the future. In addition, this study can contribute to improving the understanding of both private companies and public organizations who are interested in the cost-benefit analysis and estimation procedure for the publicly financed projects.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.202-203
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• 2020

Unlike price calculation by cost accounting, which categorizes costs into material costs, labor costs, and miscellaneous expenses to determine the construction budget price, construction cost calculation based on Construction Standard Unit Prices utilizes unit prices extracted from market prices of items from projects already completed to estimate costs of similar construction projects. Although unit price information is collected through construction site surveys to revise these construction standard unit prices every year, but due to the limitations of the site survey method, it is difficult to quickly implement the rapid changes in the construction methods and market prices. As such, an important issue that arose was the identification of work items whose prices need urgent revision. This study conducted research on factors that need to be considered when developing online survey system for monitoring construction site market prices. This study is expected to enhance convenience for users, and provide an efficient data collection and management system for administrators.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.274-277
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• 2006

The EAC(Estimate at Completion) among existing methods, which estimate cost and time effectively, help managers anticipate changeable several results at the point of $15{\sim}30%$ in the project progress. However, this method may cause such some problems as not to consider the periodically changing circumstances caused by construction risks or uncertainties which can affect the cost and time in the project, and to regard collected and accumulated data only as a single value when predicting the results on the progress. Accordingly, it is very difficult to accept the even small range of variability based on the anticipation of EAC. Consequently, the study focuses on the possibility methodology to anticipate time and cost accurately on the way to utilize EVMS(Earned Value Management System), and also suggest the way to perform the right estimation of EAC as considering various risks and uncertainties in construction projects.

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.65-74
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• 2008

Public institutions recognize the importance of cost management from the planning stage but they do not have an organized construction cost estimation and management system. Thus, at the stage of planning a new public construction project and estimating the cost, those in charge of budgeting estimate construction cost based on existing data and experiences, compare construction cost estimated after the basic design stage and the execution design stage with budgets, and then decide whether to continue the project or change the design according to the budgets. Therefore, we would develop the cost prediction model through regression analysis that can predict construction cost in Schematic Design Phase of the Public Multi-Family housing. Accordingly, if public institutions have a construction cost prediction model and management system that can estimate the optimum construction cost, they can make and execute budgets in a more efficient way than they do at present.