Multimode time-cost-robustness trade-off project scheduling problem under uncertainty

The time/cost trade-off problem is a well-known project scheduling problem that has been extensively studied. In recent years, many researchers have begun to focus on project scheduling problems under uncertainty to cope with uncertain factors, such as resource idleness, high inventory, and missing deadlines. To reduce the disturbance from uncertain factors, the aim of robust scheduling is to generate schedules with time buffers or resource buffers, which are capped by project makespan and project cost. This paper addresses a time-cost-robustness trade-off project scheduling problem with multiple activity execution modes under uncertainty. A multiobjective optimization model with three objectives (makespan minimization, cost minimization, and robustness maximization) is constructed and three propositions are proposed. An epsilon-constraint method-based genetic algorithm along with three improvement measures is designed to solve this NP-hard problem and to develop Pareto schedule sets, and a large-scale computational experiment on a randomly generated dataset is performed to validate the effectiveness of the proposed algorithm and the improvement measures. The final sensitivity analysis of three key parameters shows their distinctive influences on the three objectives, according to which several suggestions are given to project managers on the effective measures to improve the three objectives.

     

A positive psychology intervention to foster economic integration of Syrian refugees in the Netherlands

Research shows that the labour market integration of refugees is often problematic. Little is known about what kind of measures are effective to help them integrate into the labour market. In the Netherlands, a positive psychology intervention “Mosaic” for Syrian refugees was developed to support their economic participation. This study aims to assess the effect of “Mosaic” on the economic participation and work-related attitudes of Syrian refugees. “Mosaic” was implemented in six municipalities by conducting an RCT with a waiting list control group. The results show that in the short term, the intervention group realizes a significantly larger increase in hours spent on an internship as well as substantially larger gains in confidence to find work in the future. In the long term, the intervention group experiences larger confidence gains related to finding a job that fits their education and experience.