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AF comments for last week done, now CH2 and janet and john Weeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

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Robin Clark 2013-09-08 12:15:55 +01:00
parent f7c7aa33a2
commit 5c5dade1fa
6 changed files with 31 additions and 27 deletions
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1
submission_thesis/CH1_introduction/copy.tex
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@ -284,6 +284,7 @@ was presented to the IET System safety conference in 2011,~\cite{syssafe2011}.
%
FMEA, currently cannot integrate software models into its hardware failure mode models~\cite{sfmea,modelsfmea,embedsfmea,sfmeainterface}, but
%
\fmmdglossCONTRACTPROG
FMMD can use the existing structure of functional software, in conjunction
with contract programming to model software;
%and

4
submission_thesis/CH3_FMEA_criticism/copy.tex
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@ -186,8 +186,8 @@ as defined in equation~\ref{eqn:fmea_single},
%
% This figure would mean we could compare the maximum number of checks (i.e. exhaustive %rigorous
% analysis) with the number actually performed.
Comlexity comparision here, means the maximum number of checks (i.e. exhaustive %rigorous
analysis) could be compared to the number actually performed.
Complexity comparison here, means the maximum number of checks (i.e. exhaustive %rigorous
analysis) compared to the number actually performed.
%
In effect a yard~stick for the amount of work performed
for a particular FMEA analysis technique/strategy.

2
submission_thesis/CH4_FMMD/copy.tex
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@ -1436,7 +1436,7 @@ mode could be considered in the context of all other components in the system---
%
With FMMD, because the {\fgs} have small numbers of components in them, we can easily apply XFMEA within the {\fgs}.
%
In broad terms, FMMD mitigates state explosion by reducing the number of checks---{\fms} against components)---to perform.
In broad terms, FMMD mitigates state explosion by reducing the number of checks---{\fms} against components---to perform.
%
This issue addressed formally in section~\ref{sec:cc}.
\fmmdgloss

19
submission_thesis/CH8_Conclusion/copy.tex
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@ -53,7 +53,8 @@ A unitary state failure mode concept was developed (see section~\ref{sec:unitary
the FMMD process naturally enforced this throughout the hierarchy of a model.
\fmmdglossMUTEX
%
Finally the FMMD process was described algorithmically using set theory in appendix~\ref{sec:algorithmfmmd}.%{app:alg}.
Finally the FMMD process was described algorithmically % using set theory
in appendix~\ref{sec:algorithmfmmd}.%{app:alg}.
In conclusion then, a new method of failure analysis has been devised which improves on established techniques in the following ways:
% \begin{itemize}
@ -68,8 +69,8 @@ In conclusion then, a new method of failure analysis has been devised which imp
% \end{itemize}
\fmmdglossSTATEEX
\begin{itemize}
\item FMMD provides the means to create failure models that integrate software and hardware,
\item the state explosion related to exhaustive FMEA solved,
\item FMMD provides the means to determine failure models that integrate software and hardware,
\item the state explosion related to exhaustive FMEA reduced from a polynomial to logarithmic order,
\item a modular approach to FMEA means that analysis work is re-usable,
%\item FMMD encourages
\item distributed systems, and smart instruments, can now be analysed and assessed,
@ -79,7 +80,7 @@ These benefits fall under the following assumptions and constraints:
\begin{itemize}
\item Failure modes are available for all {\bcs},
\item Analysts are capable of finding suitable {\fgs} from electronic schematics,
\item Software is hierarchical and its elements (functions) can be modelled using contract programming.
\item Functional software and its elements (hardware interfaces, data and functions) can be modelled using contract programming.
%\item
\end{itemize}
\fmmdglossRD
@ -158,7 +159,7 @@ in hours for a wide range of generic components
can give conservative reliability figures when applied to
modern components}.
%
Using the MIL-HDBK-217F%~\cite{mil1991}
Using the MIL-HDBK-217F %~\cite{mil1991}
specifications for resistor and thermistor failure statistics, the reliability for the Pt100 example (see section~\ref{sec:Pt100}) is calculated below.
%
%
@ -526,7 +527,7 @@ all failure modes of the resultant {\dcs} as we progress up a hierarchy.
FMMD requires that all failure modes of components in a {\fg} are resolved to
a symptom in the resulting {\dc}.
%
Because we can enforce a `complete' analysis, FMMD can find failure modes were missed by
Because we can enforce a `complete' analysis, FMMD can find failure modes which were missed by
other FMEA processes; meaning that the FMMD process can expose un-handled
failure modes.
%come to light.
@ -562,7 +563,7 @@ leading to idealised XFMEA requirements (see section~\ref{sec:reasoningdistance}
Using FMMD only those modules in the hierarchy above the
component with the new failure mode need be re-visited.
%
The failure mode DAGs can be traced to determine exactly which
The failure mode DAGs (see section~\ref{sec:chap4}) can be traced to determine exactly which
{\fgs} exist in the hierarchy above the affected {\bcs}.
%
This means that with FMMD the re-work task can be precisely defined.
@ -570,7 +571,9 @@ This means that with FMMD the re-work task can be precisely defined.
Also where a new {\bc} {\fm} is merged with an existing symptom in the analysis
the re-work need not continue above it in the hierarchy.
%
This could be automated in a software tool that can traverse the failure mode trees.
That is a new {\bc} {\fm} may cause a symptom already found in the analysis hierarchy.
%
Finding these could be automated in a software tool that can traverse the failure mode trees.
%
% By %doing
% applying contracts and seeing how calling functions deal with

26
submission_thesis/appendixes/detailed_analysis.tex
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@ -833,54 +833,54 @@ FMMD analysis tables from chapter~\ref{sec:chap6}.
\label{sec:gnuplotxfmeafmmdcomp}
\begin{verbatim}
##
#####################################################################################
# GNUPLOT SCRIPT to plot XFMEA FMMD reasoning distance
# comparisons.
#
#
# alway define fp in declaration, as in 'C'
# or gnuplot treats these as integers.
# Always define floating point explicitly at initialisation, as in 'C',
# because otherwise gnuplot treats these as integers.
#
# number of failure modes per component
fm = 3.0
#
# number of components in each functional group
k = 3.0
#
# place the functional group size and failure mode per components
# size into a string to use as the graph title
#
tt = sprintf("reasoning distance comparison for |fg| = %d and |fm| = %d", k, fm)
set title tt
#
a = 0.0
b = 0.0
#
# formula for reasoning distance in one level of FMMD
# hierarchy (as given by ll)
#
fmmd(ll)=k**ll * k * fm * (k - 1)
#
# set up iterative sum in gnuplot syntax
# to iterate over FMMD levels
#
sum(a,b) = (a > b) ? 0 : fmmd(a) + sum(a+1, b)
sig_fx(c) = sum(a,c)
#
# reasoning distance for exhaustive case in FMEA
# where ll is the hierarchy level
xfmea(ll) = k**(ll+1) * ( k**(ll+1) -1 ) * fm
#
#
set xrange [0:1000]
set xlabel "Component count"
set ylabel "reasoning distance"
set logscale y
#
set terminal png
set output 'xfmea_fmmd_comp.png'
plot sig_fx(x**(1/k)), xfmea(x**(1/k))
#!sleep 20
#####################################################################################
\end{verbatim}

6
submission_thesis/style.tex
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@ -127,8 +127,8 @@ Software Fault Tree Analysis (SFTA):
top down failure investigation applied to software}}}
\newcommand{\fmmdglossSA}{\glossary{name={Symptom Abstraction},description={
By applying failure mode analysis to a module, the symptoms of failure for the it are determined
given the failure modes of its components, its topology and expected behaviour.}}}
By applying failure mode analysis to a module the symptoms of failure for it are determined
given the failure modes of its components, its topology and its expected behaviour}}}
\newcommand{\fmmdglossMUTEX}{\glossary{name={mutually~exclusive},description={
Mutual exclusivity applied to component failure modes
@ -138,7 +138,7 @@ only one of its failure modes may be active at any given time}}}
\newcommand{\fmmdglossSTATEEX}{\glossary{name={State~explosion},description={
State Explosion is the effect where very large numbers of combinations of conditions, or combinations of
conditions and entities have to be processed. The number to be processed can quickly become too large
for practical consideration, and when this happens `state~explosion' can be said to have occurred.
for practical consideration, and when this happens `state~explosion' can be said to have occurred
}}}
\newcommand{\fmmdglossFTA}{\glossary{name={FTA},description={