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Notes from J Howse 19NOV2010 Meeting

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Robin Clark 2010-11-21 20:16:04 +00:00
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6
symptom_ex_process/introduction.tex
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@ -12,9 +12,7 @@ In the field of safety engineering this derived component corresponds to a low~
%The technique uses a graphical notation, based on Euler\cite{eulerviz} and Constraint diagrams\cite{constraint} to model failure modes and failure mode common symptom collection. The technique is designed for making building blocks for a hierarchical fault model. %The technique uses a graphical notation, based on Euler\cite{eulerviz} and Constraint diagrams\cite{constraint} to model failure modes and failure mode common symptom collection. The technique is designed for making building blocks for a hierarchical fault model.
% %
Once the failure modes have been determined for a sub-system/{\dc}, Once the failure modes have been determined for a sub-system/{\dc},
this {\dc} can be combined with others to form {\fgs} groups this {\dc} can be combined with others to form {\fgs} to model higher level sub-systems/{\dcs}.
to model
higher level sub-systems/{\dcs}.
% %
In this way a hierarchy to represent the fault behaviour In this way a hierarchy to represent the fault behaviour
of a system can be built from the bottom~up. This process can continue of a system can be built from the bottom~up. This process can continue
@ -30,7 +28,7 @@ Once a hierarchy is in place, it can be converted into a fault data model.
From the fault data model, automatic generation From the fault data model, automatic generation
of FTA \cite{nasafta} (Fault Tree Analysis) and mimimal cuts sets \cite{nucfta} are possible. of FTA \cite{nasafta} (Fault Tree Analysis) and mimimal cuts sets \cite{nucfta} are possible.
Also statistical reliability/probability of failure~on~demand \cite{en61508} and MTTF (Mean Time to Failure) calculations can be produced Also statistical reliability/probability of failure~on~demand \cite{en61508} and MTTF (Mean Time to Failure) calculations can be produced
automatically \footnote{Where component failure mode statistics are available \cite{mil1991}}. automatically\footnote{Where component failure mode statistics are available \cite{mil1991}}.
% %
This chapter focuses on the process of converting {\fgs} to {\dcs}, or building the `blocks' of the FMMD hierarchy. This chapter focuses on the process of converting {\fgs} to {\dcs}, or building the `blocks' of the FMMD hierarchy.
We can term this stage in FMMD analysis as the `symptom extraction' process. We can term this stage in FMMD analysis as the `symptom extraction' process.

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symptom_ex_process/paper.tex
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@ -6,6 +6,7 @@
\usepackage{amsfonts,amsmath,amsthm} \usepackage{amsfonts,amsmath,amsthm}
\usepackage{algorithm} \usepackage{algorithm}
\usepackage{algorithmic} \usepackage{algorithmic}
\usepackage{lastpage}
\usepackage{ifthen} \usepackage{ifthen}
\newboolean{paper} \newboolean{paper}
\setboolean{paper}{true} % boolvar=true or false \setboolean{paper}{true} % boolvar=true or false
@ -16,6 +17,15 @@
\begin{document} \begin{document}
\pagestyle{fancy} \pagestyle{fancy}
\fancyhf{}
%\renewcommand{\chaptermark}[1]{\markboth{ \emph{#1}}{}}
\fancyhead[LO]{}
\fancyhead[RE]{\leftmark}
%\fancyfoot[LE,RO]{\thepage}
\cfoot{Page \thepage\ of \pageref{LastPage}}
\rfoot{\today}
\lhead{The Symptom Extraction process of FMMD}
%\outerhead{{\small\bf Symptom Extraction Process}} %\outerhead{{\small\bf Symptom Extraction Process}}
%\innerfoot{{\small\bf R.P. Clark } } %\innerfoot{{\small\bf R.P. Clark } }

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symptom_ex_process/top_down_de_comp.dia
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symptom_ex_process/top_down_de_comp.jpg
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symptom_ex_process/topbot.tex
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@ -1,5 +1,5 @@
\section{Fault Finding \\ and Failure Mode Analysis} \section{Fault Finding and Failure Mode Analysis}
\subsection{Static Analysis} \subsection{Static Analysis}
@ -23,7 +23,7 @@ can be derived.
FMMD can model electrical, mechanical and software using a common notation, FMMD can model electrical, mechanical and software using a common notation,
and can thus model an entire electro-mechanical software controlled system. and can thus model an entire electro-mechanical software controlled system.
\subsection{Top Down or \\ natural trouble shooting} \subsection{Top Down or natural trouble shooting}
It is interesting here to look at the `natural' trouble shooting process. It is interesting here to look at the `natural' trouble shooting process.
Fault finding is instinctively performed from the top-down. Fault finding is instinctively performed from the top-down.
A faulty piece of equipment is examined and will have a A faulty piece of equipment is examined and will have a
@ -49,6 +49,7 @@ Top down formal fault isolation/finding techniques for electronics are described
%% %%
%% insert diagram here %% insert diagram here
\begin{figure}[h] \begin{figure}[h]
\centering \centering
\includegraphics[width=300pt,bb=0 0 587 445,keepaspectratio=true]{symptom_ex_process/top_down_de_comp.jpg} \includegraphics[width=300pt,bb=0 0 587 445,keepaspectratio=true]{symptom_ex_process/top_down_de_comp.jpg}
@ -85,7 +86,10 @@ The effects on the functional group can then be collected as common symptoms,
and now we may treat the functional group as a component, as it has a known set of failure modes. and now we may treat the functional group as a component, as it has a known set of failure modes.
% %
By reusing the `components' derived from functional~groups an entire By reusing the `components' derived from functional~groups an entire
hierarichal failure mode of the system can be built. hierarichal failure mode model of the system can be built.
That is to say, using derived components in higher level functional groups
a hierarchy is naturally formed.
%
By working from the bottom up, we can trace all possible sources By working from the bottom up, we can trace all possible sources
that could cause a particular mode of equipment failure. that could cause a particular mode of equipment failure.
This means that at the design stage of a product all component failure This means that at the design stage of a product all component failure
@ -114,7 +118,7 @@ These are listed in table~\ref{tab:symexdef}.
A system, is any coherent entity that would be sold as a product. % safety critical product. A system, is any coherent entity that would be sold as a product. % safety critical product.
A sub-system is a system that is part of some larger system. A sub-system is a system that is part of some larger system.
For instance a stereo amplifier separate is a sub-system. The For instance a stereo amplifier separate/slave is a sub-system. The
whole sound system, consists perhaps of the following `sub-systems': whole sound system, consists perhaps of the following `sub-systems':
CD-player, tuner, amplifier~separate, loudspeakers and ipod~interface. CD-player, tuner, amplifier~separate, loudspeakers and ipod~interface.