Abstract: Project scheduling is intended to allocate limited resources to appropriate activities and achieve the goal of optimal project construction period. It is an important means to optimize project resource allocation and shorten project construction period. In the process of scheduling, how to choose the appropriate activity based on limited resources in different periods is the key to solution. Based on the objective of minimum project construction period, from the perspective of activity combination, this paper designs a new project scheduling mechanism with the framework of branch and bound process, nested task combination optimization strategy and heuristic priority rules. In this process, firstly, breadth-first search is used to determine the activities to be decided and the branching time, and then the branching optimization and pruning process of the tree are completed based on the activity combination optimization strategy and depth-first search respectively. Finally, the experimental test is completed through an example and PSPLIB, and the traditional heuristic scheduling mechanism is compared to analyze the impact of different project environments on the scheduling and verify the effectiveness of the mechanism. The results show that the proposed scheduling mechanism is more efficient than the traditional heuristic scheduling mechanism in solving both the average project construction period and the optimal scheduling proportion. This conclusion can further guide project management practices and provide scientific decision-making basis for actual project scheduling.

Key words: project scheduling, activity combination optimization, priority rule, breadth-first search, depth-first search