Research Of Multi-project Robust Scheduling Based On Critical Chain

As today's project are highly innovative, large scale and require complex resource with a high degree of parallelism, scheduling schemes are often difficult to be implemented as scheduled. In this case, scholars began to expand the resource constrained multi-project robust scheduling that not only takes into account the resource constraints, but also gives full consideration to the practical implementation of the project with various uncertainties. The resource constrained multi-project robust scheduling can be effective against the risk of project delays and improves the quality of completion of the project, and have high academic and practical value.Since its inception, critical chain project management theory has been widely applied with great success. Practical application of the critical chain project scheduling has proved that it can effectively shorten the project duration, while increasing the rate of on time project completion. However, time-limits of projects in critical chain project scheduling become less sensitive to the change of durations through cutting task duration and setting concentrated buffer. It also makes the duration of single task easily be extended and lead to the start time of subsequent missions become unstable. Therefore, the solution robustness of scheduling becomes poor. In order to solve this problem, a multi-project critical chain based robustness scheduling model aiming at maximizing the robustness indicator and minimizing durations of projects is proposed.To solve this model, the traditional multi-project scheduling based on critical chain search their own critical chain for each projects, and are then staggered to avoid bottlenecks in the implementation, this approach can easily lead to a new bottleneck in dealing with multiple resource constraints complex multi-project scheduling problem, and make it difficult to generate an effective multi-project critical chain scheduling. Also traditional approach which is limited to a certain set of priority rules can not find an optimal solution. Therefore, we propose a multi-project critical chain scheduling hybrid optimization algorithm; the algorithm is divided into two modules. To break the limitations of priority rules, it uses genetic algorithms to find the optimal priority list of project activities; to solve the problem that traditional multi-project critical chain scheduling algorithm faces when solving complex resource-constrained project scheduling, using priority-based multi-project critical chain scheduling algorithm. Two algorithms combined with each other, ensures the critical chain scheduling with better solution robustness and quality robustness. The proposed robustness scheduling model and hybrid algorithm are verified by a case study. Simulation results show that the robustness of scheduling has been improved significantly.Finally, a summary of the paper is given and the further research trends are outlined.