S. M. Seyed-Hosseini - Department of Industrial Engineering, Iran University of Science & Technology,
Majid Sabzehparvar - Department of Industrial Engineering, Iran University of Science & Technology,
Siamac Nouri - Department of Industrial Engineering, Iran University of Science & Technology,

This paper presents an exact model and a genetic algorithm for the multi-mode resource constrained project scheduling problem with generalized precedence relations in which the duration of an activity is determined by the mode selection and the duration reduction (crashing) applied within the selected mode. All resources considered are renewable. The objective is to determine a mode, the amount of continuous crashing, and a start time for each activity so that all constraints are obeyed and the project duration is minimized. Project scheduling of this type occurs in many fields; for instance, predicting the resources and duration of activities in software development projects. A key feature of the model is that none of the typical models can cope with the continuous resource constraints. Computational results with a set of 100 generated instances have been reported and the efficiency of the proposed model has been analyzed.

Crashable modes; Multi-mode; Time/resource trade-off; Time windows