Fuzzy modus ponens deduction technique for construction scheduling

This paper presents a new method to estimate the duration of construction activities. A model, Activity Duration Decision Support System (ADDSS), was developed. This model employs the fuzzy modus ponens deduction (FMPD) technique to evaluate the impact of different factors on activity duration. The linguistic values of these factors are represented by angular fuzzy set models. The technique described in this paper allows a scheduler to partially match an evidence with a rule. The use of angular models demonstrates the use of a single and relatively simple fuzzy logic formula. The technique we developed does not require the scheduler to understand the underlying concept of fuzzy logic. In fact, one needs only to input an assessment of factors that may affect the completion of an activity. At this stage, ADDSS interfaces with the CA-SuperProject scheduling package. ADDSS was also developed to export and import data to and from the CA-SuperProject. Both the logic operations and angular models of ADDSS are elaborated. A step-by-step procedure using ADDSS is presented, followed by case studies demonstrating the implementation of ADDSS in hypothetical and real construction projects. These cases show the practicality and applicability of ADDSS.