diff --git a/component_failure_modes_definition/cfg2.dia b/component_failure_modes_definition/cfg2.dia new file mode 100644 index 0000000..fefc0ad Binary files /dev/null and b/component_failure_modes_definition/cfg2.dia differ diff --git a/component_failure_modes_definition/cfg2.jpg b/component_failure_modes_definition/cfg2.jpg new file mode 100644 index 0000000..2290552 Binary files /dev/null and b/component_failure_modes_definition/cfg2.jpg differ diff --git a/component_failure_modes_definition/component_failure_modes_definition.tex b/component_failure_modes_definition/component_failure_modes_definition.tex index 0e6dc44..3023182 100644 --- a/component_failure_modes_definition/component_failure_modes_definition.tex +++ b/component_failure_modes_definition/component_failure_modes_definition.tex @@ -727,10 +727,91 @@ such as Bayes theorem~\cite{probstat}. %%- \section{Complete UML Diagram} +For a complete UML data model we need to consider the System +as an object. This holds a parts list, and is the +key reference point in the data structure. + +A real life system will be expected to perform in a given environment. +Environment in the context of this study +means external influences the System could be expected to work under. +A typical data sheet for an electrical component will give +a working temperature range for instance. +Mechanical components will be specified for stress and loading limits. + +\paragraph{Environmental Modelling.} The external influences/environment could typically be temperature ranges, +levels of electrical interference, high voltage contamination on supply +lines, radiation levels etc. +Environmental influences will affect specific components in specific ways. +Environmental analysis is thus applicable to components. +\paragraph{Operational states.} +Within the field of safety critical engineering we often encounter +sub-system that include test facilities. We also encounter degraded performance +(such as only performing functions in an emergency) and lockout conditions. +These can be broadly termed operational states, and apply to the +functional groups. +Consider for instance an electrical circuit that has a TEST line. +When the TEST line is activated, it supplies a test signal +which will validate the circuit. This circuit will have two operational states, +NORMAL and TEST mode. + +It is natural to apply the operational states to functional groups. +Functional groups by definition implement functionality, or purpose +of particular sub-systems, and therefore are the best objects to model +operational states. + +\paragraph{UML Diagram Additional Objects.} +The additional objects System, Environment and Operational States +are added to UML diagram in figure \ref{fig:cfg} and represented in figure \ref{fig:cfg2}. + + +\begin{figure}[h] + \centering + \includegraphics[width=400pt,keepaspectratio=true]{./component_failure_modes_definition/cfg2.jpg} + % cfg2.jpg: 702x464 pixel, 72dpi, 24.76x16.37 cm, bb=0 0 702 464 + \caption{Complete UML diagram} + \label{fig:cfg2} +\end{figure} + + + \section{From UML Model to Data Model} + +HERE should how the hierarchy is built, how the inheritance works etc + +HAVE an example. totally theoretical. HAVE Common mode failure detection AND Common dependency detection + \subsection{Directed Acyclic Graph} + +Show how the hierarchy can be represented as a DAG + +draw a dag + \subsection{Traversing the datamodel} + +Show how we can find multiple causes for a SYSTEM level error + \subsubsection{Common mode failure detection} + +Describe what a common mode failure is. + +show how common mode failures can be detected by using the parts list (same components can all have their +error modes turned on, and the effect can be seen on the system, automatically tracing +common mode failures. + + \subsubsection{Common dependency detection} -\vspace{40pt} +The same component can be relied on by different functional groups within a system +For instance a power supply spur (i.e. supplying a particular isolated voltage say) +could have many functional groups depending or linked to its failure modes. + +Show how FMMD makes this tracable + + +% clear the page if its a paper to keep the diagram out of the references +\ifthenelse {\boolean{paper}} +{ +\clearpage +} +{ +}