Architecture Modeling - SPES 2020
Architecture Modeling - SPES 2020
Architecture Modeling - SPES 2020
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Pattern<br />
S3:<br />
Failure shall not be caused by n independent failures<br />
This pattern allows to specify that components have to be redundant and their failure may not be<br />
caused be a given number of other failures.<br />
Natural Language Requirement:<br />
Loss of engine shall not be caused by 2 independent failures.<br />
Pattern based RSL:<br />
EngineLoss shall not be caused by 2 independent failures<br />
Pattern hazard Hazard shall not occur with density higher than n per<br />
S4: reference<br />
This pattern can be used to express an hazard and specify its density.<br />
Example Pattern:<br />
hazard UnannunciatedLossOfDecelerationCapability shall not occur<br />
with density higher than 10E-9 per flightHour.<br />
There are also some patterns that allow to define some elements of the upper safety related patterns:<br />
Pattern<br />
S5:<br />
Function is realized by function_list<br />
This pattern is used to specify break-down of functions during system decomposition; function is<br />
linked to a set of functions of sub-components.<br />
In order to run safety analysis on a model, it is necessary to fully represent the flow and impact of<br />
failures. Hence the decomposition of functions has to be expressed. The commonly used black box<br />
view of components does not support the reference of elements inside a component from the<br />
outside. Since this is necessary for this decomposition a grey-box view is used. [speeds reference]<br />
Natural Language Requirement:<br />
The ABS system shall consist of the measuring unit for wheel slip and the braking system<br />
Pattern based RSL:<br />
ABSSystem is realized by WheelSlipMeasurin && BrakingSystem<br />
Pattern<br />
S6:<br />
<strong>Architecture</strong> <strong>Modeling</strong><br />
Failure is represented by failure_list<br />
This pattern is used to specify break-down of failures during system decomposition, failure is linked to<br />
a set of failures of sub-components. (see previous pattern for grey-box view).<br />
Natural Language Requirement:<br />
The braking system shall fail if the hydraulic system A fails and hydraulic system B fail.<br />
Pattern based RSL:<br />
BrakingSystemFails is represented by HydraulicSystemAFails &&<br />
HydraulicSystemBFails<br />
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