I have a scheduling problem but rather than having a fixed duration of each task, we have another "concept" that verifies the following property. Let's say task A requires a default 200 hours, then :
i) It could be done in 400 hours if it's done by an employee whose efficiency is 0.5
ii) It could be done in 100 hours if it's done by two employees both with full efficiency (i.e with an efficiency equal to 1)
There will be some constraints like: each hour of the processing of the task, the working hours of employees could not exceed a threshold. For example if a task "default duration" is 200 hours, I cannot affect more than 16 working hours each hour which may correspond to 16 regular employees each hour.
How do we call this problem? Are there any papers that deal with it?