
53Central Concepts
on weekends; the capacity of a doctor’s ofce may be zero after business
hours, and so on. Capacity may also change due to other circumstances. For
example, the recovery room nurse who ordinarily takes care of ve patients
may have a reduced capacity of one, if that patient is in severe distress or on
a medication that requires constant monitoring.
Resources typically have a cost. This can be a simple amount every time the
resource is used, or it can be a value that is determined according to various
rules. These can range from time-based rules (e.g., cost per hour of use), to
more complex ones that take into account when the ...