Model for Construction Project Scheduling and Updating Considering the Dependent Randomness of Activities

In practice, the durations of activities are not independent random variables but rather dependent random variables. In this paper, an expert system is proposed to model the dependence of activity durations in project scheduling networks and to update the schedule, in which a Bayesian network is used to describe the interdependence between activities. According to the model, the marginal distribution of activity duration and the concordance coefficient between activities are first estimated by experts; the conditional probability and distribution of the Bayesian Network is calculated consequently; and then the conditional distribution of the durations of all activities and the project duration can be determined. An expert system is constructed, which can update the distribution of the durations of unfinished activities according to the observational durations of finished activities. Results from the numerical example show that the model is promising in reducing the risk of project schedule and predicting the uncertainty of activities.