- Volume 32 Issue 3
Sigmoid modeling method, one of the widely used learning curve modeling methods, has its limits in implementing construction project cash flows, because it generates learning curve with just one single complicated formula. Therefore it needs to be developed to cope with practical situations - where many factors affect the shape of learning curves. This study adopts system dynamics modeling method to simulate S-shaped learning curves. The simulation model was constructed to apply various factors in modeling learning curves. It introduced several factors such as initial delay variance, cost variance, target date, productivity variance and these factors enable the simulation model to apply various situations of construction projects, such as schedule delay, cost increase, lagging work speed. While conventional sigmoid curve modelling is difficult to reflect changes in the middle of the project, the proposed model allows variable adjustment any time of the project progression. Statistical evaluation showed that it is 955 confident that the simulated result of the proposed model matches conventional sigmoid curve. It can be used for finding appropriate daily productivity by comparing the learning curves of target duration and actual duration, and can also be helpful forecasting cash flow features for S-shaped learning curve model.
- Gorog, M. (2009). A comprehensive model for planning and controlling contractor cash-flow, International Journal of Project Management, 27, 481-492. https://doi.org/10.1016/j.ijproman.2008.08.001
- Hwee, N., & Tiong, R. (2002). Model on cash flow forecasting and risk analysis for contracting firms, International Journal of Project Management, 20, 351-363. https://doi.org/10.1016/S0263-7863(01)00037-0
- Jimenez, L., & Pascual, L., (2008). Multicriteria cash-flow modeling and project value-multiples for two-stage project valuation, International Journal of Project Management, 26, 185-194. https://doi.org/10.1016/j.ijproman.2007.03.012
- Kim, K., (2007). System Dynamics using Vensim, Seoul Economics and Management.
- Lee M. (2006). The estimation of construciton costs by adopting the EVM mothod on the apartment housing, Journal of the Architectural Institute of Korea, Structure and Construction Section, 22(3), 147-154.
- Liu, S., & Wang, C. (2008). Resource-constrained construction project scheduling model for profit maximization considering cash flow, Automation in Construction, 17, 966-974. https://doi.org/10.1016/j.autcon.2008.04.006
- Mavrotas, G., Caloghirou, Y., & Koune, J. (2005). A model on cash flow forecasting and early warning for multi-project programmes: application to the Operational Programme for the Information Society in Greece, International Journal of Project Management, 23, 121-133. https://doi.org/10.1016/j.ijproman.2004.07.009
- Park, U. (2007). A study on the assessment model of preliminary cost estimates using support vector machines, Journal of the Architectural Institute of Korea, Structure and Construction Section, 23(4), 165-172.
- Yi, K. (2010). A Sigmoid S-curve model on cash flow forecasting for earned value management system, Journal of the Architectural Institute of Korea, Structure and Construction Section, 26(6), 103-110.