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OK CH2 needs all the 'we' and 'our' sentences

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re-written. Ballcocks. AND CH4, caryy on with AF comments.
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Robin Clark 2013-09-06 18:48:10 +01:00
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27
submission_thesis/CH3_FMEA_criticism/copy.tex
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@ -21,12 +21,12 @@ our lives safer. This chapter aims to look for the deficiencies in current FMEA
and look for ways in which it could be performed better and more efficiently.
A major problem is with the scope of
examination---i.e. which/how~many components should we check against a particular failure mode---to
examination---i.e. which/how~many components should be checked against a particular failure mode---to
apply for FMEA analysis.
%
Checking all combinations quickly leads to a state explosion problem:
defining limits for the number of components to check for against a given {\bc}
{\fm} could address this.
Checking all possible combinations of {\fms} against all components quickly leads to a state explosion problem. %:
%defining limits for the number of components to check for against given {\bc}
%{\fms} could address this.
%
The difficulties of integrating software
and hardware in FMEA failure models mean that FMEA is showing its age: designed
@ -63,7 +63,7 @@ traceable reasoning) FMEA models are presented.
Finally we conclude with a list of deficiencies in current FMEA methodologies and present a wish list
for an improved methodology.
\section{Historical Origins of FMEA: {\bc} {\fm} to system level failure/symptom paradigm}
\section{Historical Origins of FMEA and the {\bc} {\fm} to system level failure/symptom paradigm}
\subsection{FMEA: {\bc} {\fm} to system level failure modelling}
FMEA traces it roots to the 1940s when it was used to identify the most costly
@ -145,12 +145,12 @@ This can be seen as an indicator of the lack of
cause to effect precision possible when analysing
large systems using FMEA.
%
Ideally this relationship would be one to one.
Ideally this relationship would be many ({\bc} {\fms}) to one (system level symptoms).
%
This would be beneficial in terms of validating
precision of analysis, and for by-products of
the process such as developing diagnostic fault trees from
FMEA analyses.
the process such as developing diagnostic fault trees~\cite{cbds}[Ch 6.2] from
FMEA results.
\section{Comparison Complexity}
%\section{Reasoning Distance used to measure Comparison Complexity}
@ -177,16 +177,17 @@ other system level symptoms.
% Were we to compare the reasoning distance with the theoretical maximum, the sum of all failure
% modes in a system, multiplied by the number of components in it, we could arrive at a maximum
% reasoning distance, which we can use as a comparison complexity figure.
If the reasoning distance is compared with the theoretical maximum, i.e.
as defined in equation~\ref{eqn:fmea_single}, this can be used as a comparison complexity figure.
If a reasoning distance used is compared with the theoretical maximum, i.e.
as defined in equation~\ref{eqn:fmea_single},
comparison complexity figures can be produced.
%
% This figure would mean we could compare the maximum number of checks (i.e. exhaustive %rigorous
% analysis) with the number actually performed.
This figure would mean this maximum number of checks (i.e. exhaustive %rigorous
Comlexity comparision means this maximum number of checks (i.e. exhaustive %rigorous
analysis) could be compared to the number actually performed.
%
In effect a yard~stick for the efficiency, in terms of work,
for a particular analysis technique.
In effect a yard~stick for the amount of work performed
for a particular FMEA analysis technique/strategy.
\paragraph{The ideal of exhaustive FMEA (XFMEA).}
%

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submission_thesis/CH4_FMMD/instance_diagram_NONINVAMP.dia
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