Pooled Resources

Suppose you are scheduling training sessions and each session requires a room, an instructor, and a laptop for each student.  You want to assign the rooms and instructors by name, but you don’t care which laptops are assigned to the trainees.  The laptops are a “pool” of resources.

Or suppose you are scheduling an auto repair facility.  Each repair job requires a service bay, but you don’t need to assign each particular bay.  You only want to be sure there are enough bays to make the schedule feasible.  The service bays are a “pool” of resources that could be constraining if sufficient quantities were not available.

In the event planning business, you need rooms, people, tables and chairs.  Obviously you don’t need to schedule each chair!  The chairs and tables are “pools”.

Many scheduling applications handle resource assignments for individual resources, but not for pooled resources.  The FAST system removes this restriction and allows an activity’s resource requirements to include any number of both pooled and individual resources.

As schedules get developed, the availability profiles for pooled resources begin to look like city skylines with lots of notches in them.  Technically these resource profiles are piece-wise constant time profiles.  That is, they are sets of consecutive intervals with different quantities associated with each interval.  As activities are scheduled, the pooled resource requirements for each activity must be compared to these notched availability profiles to determine if the activity can be scheduled.  The FAST system does these profile comparisons and determines all of the time intervals that the activity’s requirements can be met.

Finally, suppose that the activity you are scheduling requires different quantities of pooled resources over the duration of the activity.  For example, a construction activity might require three forklifts for the first 90 minutes and only two  thereafter.  Now we have a notched profile for the forklift requirement that must be compared to the current notched availability profile for forklifts.  Recognize that  forklifts are also being used by many other activities.  It is  very difficult  for a scheduler to figure out when the activity is feasible.  The FAST system does this no matter how complicated the requirement profiles are, and  no matter how notched the availability profiles have become due to previous assignments affecting the original availability of the pool.  This is a huge advantage in many applications such as project scheduling, manufacturing, the hospitality industry, and health care industries.

So if you have time-varying resource requirements within an activity, how do you specify the breakpoints (times) in these profiles?  In the next post, we will describe how time is modeled in the FAST system.  Most other schedulers use pre-specified time intervals or “Buckets”.  FAST does not.  Be sure to read the next post!