Architecture Modeling - SPES 2020

Occurrences of a set of events in and arbitrary order
To specify the occurrences of a set of events without constraining their internal order, the “set”
statement can be used.
set{event1, event2, event3…} during Interval
A “set” statement is semantically equivalent to the permutation of all possible sequences of events
expressed by “and then” statements.
(event1 and then event2 and then event3 … during Interval) OR
(event1 and then event3 and then event2 … during Interval) OR
(event2 and then event1 and then event3 … during Interval) OR …
Unwanted events
Especially in sequences of events it is necessary to specify that there shall be no occurrences of some
events in a special interval:
Event not during Interval
This language construct is an event that occurs at the end of interval, if there was no occurrence of
this event. There is no relation to the filter construct “Event during interval”.
Creating Events from Conditions
It can be necessary to define the point in time where a condition becomes true or false. This is done
by the language constructs tr() and fs():
and
tr(Condition)
fs(Condition)
Architecture Modeling
Requirement:
If the cooling liquid exceeds 120 degrees celcius send a warning message.
Formalization:
whenever tr( liquitTemperature > 120) occurs
CoolingLiquidWarningMessage occurs.
To formulate requirements where a condition is true during a defined interval the following language
construct can be used:
Condition holds during Interval
Example Requirement: If the start button gets pushed signal a and signal b shall be equal for
at least 5 seconds.
116/ 156