Task 1 overlaps Task 2
The first model is shows in Figure 20. In this model
(overlapsB), Task 2 must start before the end of Task 1, but there
is no restriction on which task must finish before. In the coordination
mechanism, transition t1 send tokens to P1 and P3,
the latter indicating to Task 2 that Task 1 has already started (enables
t3 - Task 2 may start). The firing of t3 send tokens
to P5 and P4, the latter indicating to Task 1 that Task 2
has already started (enables t2 - Task 1 may finish). Task 1 has
a timeout.
To add the restriction that Task 1 must finish before Task 2 (overlapsA),
it is necessary to add an AND-join in the model (P6, P7 and
t4 in Figure 21).
Figure 20: Task 1 overlapsB Task2.
Figure 21: Task 1 overlapsA Task 2.
The same mechanisms modeled with high level PNs are shown in Figures
22 and 23.
Figure 22: Task A overlapsB Task B using high level PN.
Figure 23: Task A overlapsA Task B using high level PN.
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