Comparison Of Project Scheduling Policies In A Stochastic DTRTP Environment

With rapid development of economic and market, the environment of project becomes more and more complicate, resulting in high level of project management. In order to deal with various uncertainty in the complicated project environment, robust project scheduling has become one of the most hot and popular topic in the filed of project scheduling probelm. Especially, the Critical Chain Scheduling and Buffer Management (CC/BM) methodology and resource flow network have attack much attention to the world and have been proved to be good methodology to deal with robust project scheduling problem. CC/BM introduced the concepts of feeding buffers, project buffers and resource buffers as well as the roadrunner mentality. This last concept, in which activities are started as soon as possible, was introduced in order to speed up projects by taking advantage of predecessors finishing early on the one side. On the other side, the railway scheduling concept of never starting activities earlier than planned was introduced as a way to increase the stability of the project, typically at the cost of an increase in the expected project makespan. This dissertation applied the CC/BM and resource flow network to the multiple resource constrained project scheduling problem. Railway scheduling and roadrunner scheduling is compared in a stochastic DTRTP environment, a multi-level mixed model is built to fit the data of computational results through SAS, and the impact of resource flow network and priority list on the roadrunner scheduling and railway scheduling is analyzed.Firstly, a heuristic algorithm is proposed to identify the critical chain; some numerical results proved that this algorithm is feasible and effective. Secondly, some resource conflicts or precedence conflicts that might be occure after inserting the feeding buffer are shown and global/local branch and bound rescheduling algorithms are proposed to deal with these conflicts. Some simulations are designed to estimate the three different levels of activity uncertainty on the project completion rate and stability cost. Global branch and bound rescheduling algorithms was proved to be better than the local branch and bound rescheduling algorithms. Thirdly, CC/BM is applied to a stochastic DTRTP problem, three different experiments are designed to compare of roadrunner scheduling and railway scheduling from three different angles:the impact of feeding buffer, the impact of priority lists (critical chain priority list and other priority lists), and the impact of different level of availability. Finally, resource flow network is applied to a stochastic DTRTP environment. Retaining some good priority lists and critical chian priority list with good feeding buffer, computational experiments are simulated on the small-scale and larger-scale instances sets. A multi-level mixed model is designed to fit the data of computational results and some analysis are made for the impact of resource flow network/priority list on the roadrunner scheduling and railway scheduling by using SAS software.