中文摘要：

在资源受限条件下,综合考虑项目选择与项目调度,以最大化项目组合收益为目标函数,建立了一般化的资源受限项目组合选择及调度问题的数学模型。针对问题特性,设计了双层决策方法用于求解该问题。上层决策采用改进的蚁群优化算法求解项目组合选择问题,下层决策则采用基于优先规则的多项目调度启发式算法。采用实验设计方法系统生成24个项目组合选择与调度问题实例,对算法效果进行了对比检验。结果表明：所设计的双层决策方法对于项目组合选择及调度问题具有较好的求解效果;所建立的数学模型与解决方案能够为决策者提供平均收益更高的项目组合。

英文摘要：

A general mathematical model is established to describe the resource-constrained project portfolio selection and scheduling problem.The objective is to maximize the benefit of the selected project portfolio.A bi-level decision approach is proposed to solve the problem.At the upper level,an enhanced ant colony optimization algorithm is adopted to select project portfolios;and at the lower level,apriority rule-based heuristic is used to solve the multi-project scheduling problem.A design of experiments is used to generate 24resource-constrained project portfolio selection and scheduling instances,and the proposed bi-level decision approach is tested and compared with existing heuristics.The experimental results show that the proposed approach is significantly superior and provides better project portfolios with higher average benefits.