Buffer Evaluation for Demand Variability Using Fuzzy Logic

Chien-Ho Ko1

1Assistant Professor, Department of Industrial Engineering and Technology Management, Da-Yeh University, 112 Shan-Jiau Rd., Da-Tsuen, Chang-Hua 515, Taiwan, e-mail: fpecount@yahoo.com.tw, phone: +886-4- 8511888, fax: +886-4-8511270; Research Director, Taiwan Lean Construction Institute; Executive Director, Lean Construction Institute Asia


Precast fabricators face numerous challenges as they strive for business success. Among them, demand variability is arguably the biggest headache. The objective of the research is to develop a Buffer Evaluation Model (BEM) to protect fabricators against the impact of demand variability. Laws of forecasting are considered when developing the model. A pulling strategy of finishing production later relative to erection dates is established thereafter. To avoid fabricators losing capacity due to the relatively later fabrication, a time buffer is analyzed using Fuzzy Logic (FL). FL, in the BEM, is primarily used to deal with uncertain information encountered while evaluating time buffer. The study validates performance of the proposed method using a real precast project. Application results show that the proposed method can effectively reduce level of the inventory as well as reduce the risk of producing product falling victim to design changes.


Fuzzy logic, precast fabrication, finished goods inventory, buffer management, demand variability



Ko, C. 2006, 'Buffer Evaluation for Demand Variability Using Fuzzy Logic' In:, 14th Annual Conference of the International Group for Lean Construction. Santiago, Chile, 1-. pp 255-264

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