Well got stuck into the presentation there,

started on the software example

presentations/System_safety_2012/fmmd_software_pres.tex

@@ -8,16 +8,36 @@
 \setbeamertemplate{footline}[page number]
 
 
-\newcommand{\fg}{\em functional~group}
+%\newcommand{\fg}{\em functional~group}
-\newcommand{\fgs}{\em functional~groups}
+%\newcommand{\fgs}{\em functional~groups}
+\newcommand{\fg}{\em functional~grouping}
+\newcommand{\fgs}{\em functional~groupings}
 \newcommand{\dc}{\em derived~component}
 \newcommand{\dcs}{\em derived~components}
 \newcommand{\bc}{\em base~component}
 \newcommand{\bcs}{\em base~components}
 \newcommand{\irl}{in~real~life}
-
+\newcommand{\derivec}{\ensuremath{\mathcal{\bowtie}}}
+\newcommand{\ft}{\ensuremath{4\!\!\rightarrow\!\!20mA} }
 \begin{document}
 
+
+
+\section{Applying failure Mode Modular de-Composition to integrated electronic and software Systems}
+\begin{frame}
+\frametitle{Failure Mode Modular De-Composition(FMMD)}
+\begin{itemize}
+  \pause \item FMMD is a modularised variant of FMEA
+   \pause \item FMMD can model integrated mechanical, electrical and software systems.
+   \pause \item FMMD has efficiency benefits (re-use reduced complexity of checking) compared to traditional FMEA
+  \pause \item FMMD models can be used to assist in the production of traditional FMEA based
+  methodologies (PFMEA, FMECA, FMEDA FTA etc.)
+\end{itemize}
+%\tableofcontents[currentsection]
+\end{frame}
+
+
+
 \section{F.M.E.A.}
 \begin{frame}
 \frametitle{FMEA}
@@ -28,9 +48,9 @@
 
 \begin{frame}
 \frametitle{FMEA}
-This talk introduces Failure Mode Effects Analysis, and the different ways it is applied.
+We now talk about Failure Mode Effects Analysis, and the different ways it is applied.
 These techniques are discussed, and then
-a refinement is proposed, which is essentially a modularisation of the FMEA process.
+a refinement(FMMD) is proposed, which is essentially a modularisation of the FMEA process.
 %
 
 \begin{itemize}
@@ -654,8 +674,8 @@ judged to be in critical sections of the product.
   \pause \item Collect Symptoms.
   \pause \item Create a '{\dc}', where its failure modes are the symptoms of the {\fg} from which it was derived.
   \pause \item The {\dc} is now available to be used in higher level {\fgs}.
-  %\pause \item We can represent this process as a function which converts a {\fg} into a {\dc} and use the symbol $ \bowtie $ to represet it.
+  %\pause \item We can represent this process as a function which converts a {\fg} into a {\dc} and use the symbol $ \derivec $ to represet it.
-  \pause  $ \bowtie ( FunctionalGroup ) \rightarrow {DerivedComponent} $
+  \pause  $ \derivec ( FunctionalGroup ) \rightarrow {DerivedComponent} $
   %\item could use AMALG instead here $ \amalg $
 \end{itemize}
 \end{frame}
@@ -914,7 +934,7 @@ with equation~\ref{eqn:anscen}.
 % and equation~\ref{eqn:anscen}.
 % \clearpage
 
-%\section{Example}/bowtie
+%\section{Example}/derivec
 \begin{frame}
 \frametitle{FMMD - Failure Mode Modular De-Composition}
 To see the effects of reducing `state~explosion' we can use an example.
@@ -1024,7 +1044,7 @@ missed in an analysis.
 
 
 
-\subsection{conclusion}
+\subsection{FMMD summary}
 \begin{frame}
 \frametitle{FMMD - Failure Mode Modular De-Composition}
 \textbf{Conclusion: FMMD}
@@ -1037,9 +1057,133 @@ missed in an analysis.
 \end{itemize}
 \end{frame}
 
+\section{Software and Failure Mode Effects Analysis}
+
+\subsection{Software and FMEA---Current work}
 \begin{frame}
-\frametitle{FMMD - Failure Mode Modular De-Composition}
+ \frametitle{Software FMEA (SFMEA) --- Current work }
-\textbf{Questions?}
+ %\paragraph{Current work on Software FMEA}
+\begin{itemize}
+ \pause \item SFMEA is performed in isolation to hardware FMEA
+  \pause \item SFMEA considers all variables within a function as potentially corruptible ---
+  \pause this means a large number of combinations ---  databases
+to track the relationships between variables 
+and system failure modes
+  \pause \item %Because of the large number of combinations for considering all variables as corruptible
+     automated SFMEA 
+  
+  \pause \item Some schools of thought recommend combining SFTA with SFMEA
+\end{itemize}
+% SFMEA usually does not seek to integrate
+% hardware and software models, but to perform
+% FMEA on the software in isolation~\cite{procsfmea}.
+% %
+% Work has been performed using databases
+% to track the relationships between variables 
+% and system failure modes~\cite{procsfmeadb}, to %work has been performed to 
+% introduce automation into the FMEA process~\cite{appswfmea} and to provide code analysis
+% automation~\cite{modelsfmea}. Although the SFMEA and hardware FMEAs are performed separately,
+% some schools of thought aim for Fault Tree Analysis (FTA)~\cite{nasafta,nucfta} (top down - deductive) 
+% and FMEA (bottom-up inductive)
+% to be performed on the same system to provide insight into the
+% software hardware/interface~\cite{embedsfmea}.
+% %
+% Although this
+% would give a better picture of the failure mode behaviour, it
+% is by no means a rigorous approach to tracing errors that may occur in hardware
+% through to the top (and therefore ultimately controlling) layer of software.
+\end{frame}
+
+
+\subsection{Software and FMMD}
+\begin{frame}
+\frametitle{FMMD - How to apply this to software}
+Clearly we need to be able to represent software failure modes
+in a clear and modular model.
+\end{frame}
+
+\begin{frame}
+\frametitle{FMMD - How to apply this to software}
+\begin{itemize}
+   \pause \item Software is already modular call tree, function hierarchy \pause A function can be considered as a {\fg}
+   \pause \item A function has inputs and outputs \pause these can correspond to failure modes
+   and symptoms of failure for the function
+   \pause \item We can apply contract programming, giving a function pre and post conditions
+  \pause \item Pre condition violations are analogous to component failure modes
+  \pause \item Post condition violations are analogous to symptoms of failure of the function
+\end{itemize}
+
+\end{frame}
+
+
+
+\begin{frame}
+\frametitle{FMMD - Example integrated hardware/software system --- {\ft} input}
+
+
+For the purpose of example, we chose a simple common safety critical industrial circuit
+that is nearly always used in conjunction with a programmatic element.
+A common method for delivering a quantitative value in analogue electronics is
+to supply a current signal to represent the value to be sent. %~\cite{aoe}[p.934].
+Usually, $4mA$ represents a zero or starting value and $20mA$ represents the full scale,
+and this is referred to as {\ft} signalling.
+\end{frame}
+
+\begin{frame}
+\frametitle{FMMD - Example integrated hardware/software system --- {\ft} input}
+\begin{figure}[h]
+ \centering
+ \includegraphics[width=200pt]{./ftcontext.png}
+ % ftcontext.png: 767x385 pixel, 72dpi, 27.06x13.58 cm, bb=0 0 767 385
+ \caption{Context Diagram for {\ft} loop}
+ \label{fig:ftcontext}
+\end{figure}
+%The diagram in figure~\ref{fig:ftcontext} shows some equipment which is sending a {\ft}
+%signal to a micro-controller system.
+%The signal is locally driven over a load resistor, and then read into the micro-controller via
+%an ADC and its multiplexer.
+%With the voltage detected at the ADC the multiplexer can read the intended quantitative
+%value from the external equipment.
+\end{frame}
+%
+\begin{frame}
+\frametitle{FMMD - Example integrated hardware/software system --- {\ft} input}
+General Failure behaviour of {\ft} signalling
+\begin{itemize}
+   \pause \item Electrical Current in a loop is constant (Kirchoff)
+   \pause \item Current to voltage conversion is simple at receiving end \pause a single resistor
+   \pause \item Detectable Error if outside 4mA 20mA range
+   \pause \item On disconnection \pause : 0mA, on mis-wiring\pause  : 0mA
+  %\pause \item Post condition violations are analogous to symptoms of failure of the function
+\end{itemize}
+%{\ft} has an electrical advantage as well because the current in a loop is constant. %~\cite{aoe}[p.20].
+%Thus resistance in the wires between the source and the receiving end is not an issue
+%that can alter the accuracy of the signal.
+%
+% This circuit has many advantages for safety. If the signal becomes disconnected
+% it reads an out of range $0mA$ at the receiving end. This is outside the {\ft} range,
+% and is therefore easy to detect as an error rather than an incorrect value.
+%   
+% General Failure behaviour of {\ft}.
+% 
+% Should the driving electronics go wrong at the source end, it will usually
+% supply far too little or far too much current, making an error condition easy to detect.
+% %
+% At the receiving end, one needs a resistor to convert the 
+% current signal into a voltage that we can read with an ADC.%
+\end{frame}
+
+\begin{frame}
+\frametitle{FMMD - Example integrated hardware/software system --- {\ft} input}
+ If we consider the software at the top of the failure mode hierarchy
+ the hardware is  at the bottom.
+ 
+ Yourdon, afferent---transform---efferent data flow, in an embedded system our
+ sensors---data processing/software---actuators.
+ So the electronics are the bottom.
+ 
+ Starting with the bottom-up for this {\ft} input, we have the resistor
+ 
 \end{frame}
 
 \end{document}