a) Describe how manual tasks are assigned to persons using role definitions.
b) What advantages does the usage of role definitions bring in contrast to directly allocating tasks to persons at design-time?
c) Describe situations in which role-based allocation of tasks to persons is not appropriate. Try to find extensions to classical role definitions.
Hint: As additional inspiration for this exercise you could have a look at the Workflow Resource Patterns (see http://workflowpatterns.com/patterns/resource/index.php).