The Uncertain Time-Cost-Quality Optimizationmodels Considering Delay Time Interval

For national key projects,post-disaster reconstruction and other construction projects,managers are more concerned about the project completion time or whether the project can be completed on time.Because project completion time is affected by greater uncertainty,we take the normal duration as the uncertain variable,the controllable duration as the decision variable,apply uncertain programming theory to project scheduling problem.In order to meet the different requirements of managers in the target project time,the corresponding optimization models are established and the solution method is given.The main contents of this paper are as follows.First,the optimization models of time and cost under uncertain environment are established.According to the different requirements of project time,three optimization models of time and cost under uncertain environment were constructed.Firstly,a programming model with the goal of minimizing the expected project time and the constraint of keeping the total cost as low as possible is built.Secondly,a programming model with the maximum possibility of project completion on schedule as the goal and the constraint of keeping total cost under control as much as possible is constructed.Finally,a programming model is established with the objective of minimizing the target project time required when the project is completed on schedule as far as possible and the total cost as far as possible not exceeding the budget.Moreover,the equivalent forms of the above models are given and proven,at the same time used for the original models.Secondly,the uncertain time-cost optimization models considering delay time interval are established.On the basis of the above time-cost optimization models,the overlapping relationships between activities in the actual project is uniformly expressed as the delay time interval into the calculation of the project time.Therefore,three models including the expected project time minimization model,the project time chance maximization model and the ?-time minimization model were constructed.Moreover,the equivalent forms of the above models are given and proven,at the same time used for the original models.Thirdly,the uncertain time-cost-quality optimization models considering delay time interval are established.The expression of project quality is determined according to the linear relationship between activity quality level and duration,and between activity quality and total quality.On the basis of the above time-cost optimization models considering delay time interval,the quality of the project meeting the target requirements as far as possible was introduced into the programming models as a constraint,and three uncertain time-cost-quality optimization models considering delay time interval were built.Moreover,the equivalent forms of the above models are given and proven,at the same time used for the original models.Finally,the validity of the proposed models is verified by engineering cases.This paper further enriches the research results of project scheduling problem and broadens the application scope of uncertain programming theory.