Hyun-Seok Moon

CBR-based cost prediction model-II of the design phase for multi-family housing projects

Predicting adequate construction cost is an important factor in effective investment because owners must set the most appropriate budget for their projects. Unlike the existing cost prediction models, the variables that have an interrelation with construction cost were selected as attributes using correlation analysis based on 786 cases. In selecting the attribute weight, the cost prediction model-II for construction projects was developed using the genetic algorithm. The developed cost prediction model-II was verified with four project cases. The result of the verification showed error ratios of -2.57%, -4.25%, 5.25%, and 4.59%, respectively. The developed cost prediction model-II can predict construction cost that corresponds with the project characteristics. It can also be expected that the developed model is effective in design management and cost management since the construction cost can be predicted before the completion of a projects design stage.

Selection Model for Delivery Methods for Multifamily-Housing Construction Projects

Selecting an appropriate delivery method that will achieve a project’s objectives and characteristics is one of the most critical factors for the project’s success. A selection model for this study was developed by using actual construction case data in quantitative data analysis methods such as logistic regression, factor analysis, and correlation analysis. The model was developed on the basis of the design-build and design-bid-build methods from various project delivery methods. To validate the developed model, comparative tests were conducted on the selection of the delivery method for multifamily-housing construction projects, which showed that the model resulted in 95.0% accuracy. It is expected that the developed selection model will enable owners to select delivery methods that accurately meet their needs characteristics, project characteristics, and external environments.

Prediction Model of CO2 Emission for Residential Buildings in South Korea

AbstractThe emission of CO2 is becoming an increasingly important consideration in the construction industry, resulting in a significant amount of research actively being conducted to assess CO2 emission by using the completed designs of construction projects. However, studies on estimating CO2 emission of new construction projects remain few and far between. Thus, this study aimed at developing a model for estimating CO2 emission based on materials required in the construction and maintenance phases of residential buildings prior to design completion. Toward this end, the study used a case-based reasoning approach to predict the quantities of materials required in the construction and maintenance phases. Furthermore, through the life-cycle assessment approach, this study established a database of CO2 emission to calculate CO2 emission according to the construction materials. The study then proposed a method that could estimate CO2 emission by using the predicted quantities of materials and the establishe...

Evaluation Model for Carbon Dioxide Emissions of Construction Methods

Greenhouse gases and higher energy consumption due to industrial activities have led to serious problems such as global warming. To solve this problem, various acts are adapted and many researchers have conducted studies to propose improvements. Furthermore, the construction industry has embarked on many studies to achieve sustainability of various resources required for construction projects. Most Life Cycle Assessment models developed in previous researches for use in evaluating an environmental performance, however, were developed for a manufacture and maintenance phase of construction projects. Therefore, it is difficult to evaluate the environmental performance in a construction phase. Generally, the environmental performance in the construction phase depends on construction methods used. Therefore, in this research, to evaluate the environmental impact of the construction phase, the construction methods based on the construction process of residential buildings were reviewed. Moreover, an evaluation model for the carbon dioxide emission of the construction methods was developed based on the LCA methodology. Through the developed model, eco-friendly construction methods that can enable carbon dioxide emission reduction are expected to be selected.

Cost Prediction Model using Qualitative Variables focused on Planning Phase for Public Multi-Housing Projects

In planning phase of Public Multi-Housing Projects, it is required to develop the methodology and criteria for fair cost prediction with influencing power from planning phase to occupancy phase. Many studies still have focused on the prediction of cost by multiple regression. However, there is no logical explanation about the influence of nonmetric variables for the prediction of cost in planning phase. Accordingly, this research pursues a cost prediction model including nonmetric variables for use in planning phase. There are 3 steps of this research : 1) Finding the factors influencing construction cost and assigning variables for a multiple regression. 2) Conducting a dummy regression analysis with nonmetric variables and model validation by comparing actual cost data. 3) Developing the ratio of RC structure cost to wall structure cost by using cost predection model. The results could establish cost prediction process including the influence of nonmetric variables and the ratio of RC structure cost to wall structure cost.

Subject Selection Model of Green VE for Sustainable Design

As environmental issues are rising recently efforts to reduce environmental stress are emerging in all industry segments. Especially environmental impact of buildings occupy a critical portion, so each country is operating green building rating system for life cycle of buildings. Accordingly green building rating system for every facility is operating in Korea. And acquisition of grade I for building energy efficiency is mandatory for every new public buildings since 2010. To design green building efficiently and systematically eco-friendly elements should be considered and checked from the schematic design phase. But in many cases eco-friendly elements are checked at the end of constructed design phase. So applying eco-friendly elements at the value engineering process, which is performing through schematic and constructed design phase, could make a efficient and systematic green building design. Value engineering process is divided into pre workshop, workshop and post workshop stages. And subject selection in pre workshop stage is the step that finds out the subjects which has the great possibility to be improved to perform efficient value engineering workshop. So this study present the Green VE subject selection model to select the most considerable eco-friendly subjects in projects.

Improvement of Technical Proposal Tendering Evaluation Criteria for Small and Medium sized Construction Projects

The government introduced the technical proposal drafting system in September 2007, as a new method to stimulate technical competence among construction companies to require ingenuity, creativity, artistic sense, and high-level technology. However, an examination of instances has shown that this system has been applied only to large scale constructions worth 30 billion won or more, and not to small and medium constructions worth less than 30 billion won. This is because the evaluation criteria of the system is structured in a manner that makes it difficult to apply to small and medium constructions. This study presented methods to improve the evaluation factors, categories, and scoring scheme of the technical proposal creation system for medium to small scale constructions to be able to further apply the current system to small and medium constructions. The technical proposal evaluation criteria presented in this study was significant in that it enabled the technical proposal creation system that was mainly used for large scale constructions to be further applied to medium to small scale constructions. And it also contributes to the establishment and settlement of a new technical proposal tendering for medium to small scale constructions.