Java Reference
In-Depth Information
TimePlan
when
what
Resource
Task
Activity
Figure 3.1
Analysis diagram
3.2.1
Domain models
Both scenarios resemble typical job-shop scheduling problems that are well
known in the operational research field. This kind of problem is character-
ized by the exclusive use of finite-capacity resources for the execution of
process activities and tasks. Common examples can be found in the factory
automation domain, where the resources are the manufacturing facilities
(robots, machines, transports, etc.), the tasks are production jobs (e.g.
painting a car body), and the activities represent specific steps of the
production process (e.g. polishing).
An activity is characterized by five parameters.
The
type
determines the association between an activity and the
resources that can perform it as a service on demand.
■
The
release time
indicates the instant when the activity might start to be
executed if a resource is available.
■
The
activation time
is the actual instant to start the activity.
■
The
termination time
is the instant when the activity will complete its
execution according to the resource performance and the type of activity.
■
The
due time
represents the deadline when the activity is to be completed.
■
A task represents a chain of related activities. It maintains the temporal
dependencies (Figure 3.2) between activities through their release time and
due time. In reality, this definition applies to those application scenarios
where tasks are made up of activities that cannot be executed concurrently.
For example, a car body cannot be painted and polished simultaneously.
