trying to get this fir for Andrew to see

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Robin 2010-03-20 19:48:51 +00:00
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#
# Make the propositional logic diagram a paper
#
paper: paper.tex component_failure_modes_definition_paper.tex
#latex paper.tex
#dvipdf paper pdflatex cannot use eps ffs
pdflatex paper.tex
okular paper.pdf
# Remove the need for referncing graphics in subdirectories
#
component_failure_modes_definition_paper.tex: component_failure_modes_definition.tex
cat component_failure_modes_definition.tex | sed 's/component_failure_modes_definition\///' > component_failure_modes_definition_paper.tex

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\abstract{ This chapter defines what is meant by the terms \abstract{ This chapter defines what is meant by the terms
components, component fault modess and atomic component fault modes. components, component fault modess and `unitary~state' component fault modes.
Mathematical constraints and definitions are made using set theory. Mathematical constraints and definitions are made using set theory.
} }
\section{Introduction} \section{Introduction}
When building a system the components used, will have known failure modes. When building a system from components,
we should be able to find all known failure modes for each component.
For most common electrical and mechanical components, the failure modes For most common electrical and mechanical components, the failure modes
for a given type of part can be obtained from standard literature\cite{mil1991} for a given type of part can be obtained from standard literature\cite{mil1991}
\cite{mech}. \cite{mech}. %The failure modes for a given component $K$ form a set $F$.
We can define a function $FM()$ to represent thiss, where K is the component An important factor in defining a failure mode is that they
and F is the set of failure modes and A represents the set of atomic failure mode sets. should be as clearly defined as possible.
%
It should not be possible for instance for
a component to have two or more failure modes active at once.
Should this be the case, the failure modes have not been clearly analysed.
The combination could be represented by a new failure mode, or
the component should be re-analysed. A set of failure modes where only one fault mode
can be active at a time is termed a `unitary~state' failure mode set.
$$ FM : K \mapsto F | F \exits A $$ We can define a function $FM()$ to
take a given component $K$ and return its set of failure modes $F$.
$$ FM : K \mapsto F $$
We can further define a set $U$ which is a set of sets of failure modes, where
the component failure modes in each of its members are unitary~state.
Thus if the failure modes of $F$ are unitary~state, we can say $F \in U$.
\subsection{Component failure modes : Atomic definition} \subsection{Component failure modes : Unitary State example}
Electrical resistors can fail by going OPEN or SHORTED for instance. A component with simple ``unitary~state'' failure modes is the electrical resistor.
Electrical resistors can fail by going OPEN or SHORTED.
However they cannot fail with both conditions active. The conditions However they cannot fail with both conditions active. The conditions
OPEN and SHORT are mutually exlusive. OPEN and SHORT are mutually exlusive.
Because of this these failure modes can be considered `atomic'. Because of this the failure mode set $F=FM(R)$ is `unitary~state'.
A more complex component, say a micro controller could have several %A more complex component, say a micro controller could have several
faults active. It could for instance have a broken I/O output %faults active. It could for instance have a broken I/O output
and an unstable ADC input. Here the faults cannot be considered atomic. %and an unstable ADC input. Here the faults cannot be considered `unitary~state'.
A set of failure modes, where only one or no failure modes % A set of failure modes, where only one or no failure modes
are active is termed an atomic failure mode set. This % are active is termed an `unitary~state' failure mode set. This
will be donoted as set $A$. % will be donoted as set $A$.
%
To define `unitary~state' using set theory we can define a function
`active'.
The function $active(f)$ deontes that the failure mode $f$ (where $f$ is an element of $F$) is currently active.
The function $active(f)$ deontes that the failure mode f is currently active. Thus for the set $F$ to exist in $U$ the following condition must be true.
Thus for the set $F$ to exist in $A$ the following condition must be true.
\begin{equation} \begin{equation}
\label{atomic_def} \label{unitarystate_def}
active(f) | f \in F \wedge f1 \in F | f1 \neq f \wedge \neg active(f1) F \in U | f \in F \wedge active(f) \wedge f1 \in \wedge \neq f \wedge \neg active(f1)
\end{equation} \end{equation}
As an example the resistor $R$ As an example the resistor $R$
has two failure modes $_{open}$ and $R_{shorted}$. has two failure modes $R_{open}$ and $R_{shorted}$.
$$ F = FM(R) = \{ R_{open}, R_{shorted} \} $$ $$ FM(R) = F = \{ R_{open}, R_{shorted} \} $$
Applying equation \ref{atomic_definition} to a resistor Applying equation \ref{`unitarystate'_definition} to a resistor
for both fault modes for both fault modes
$$ active(R_{short}) | R_{short} \in F \wedge R_{open} \in F | R_{open} \neq R_{short} \wedge \neg active(R_{open}) $$ $$ active(R_{short}) | R_{short} \in F \wedge R_{open} \in F \wedge R_{open} \neq R_{short} \wedge \neg active(R_{open}) $$
$$ active(R_{open}) | R_{open} \in F \wedge R_{short} \in F | R_{short} \neq R_{open} \wedge \neg active(R_{short}) $$ $$ active(R_{open}) | R_{open} \in F \wedge R_{short} \in F \wedge R_{short} \neq R_{open} \wedge \neg active(R_{short}) $$
For the case of the resistor with only two failure modes the results above, being true, For the case of the resistor with only two failure modes the results above, being true,
show that the failure modes for a resistor of $ F = \{ R_{open}, R_{shorted} \} $ are atomic show that the failure modes for a resistor of $ F = \{ R_{open}, R_{shorted} \} $ are `unitary~state'
component failure modes. component failure modes.
A general case can be stated by taking equation \ref{atomnic_def} and making it a function thus. Thus
$$ FM(R) = \{ R_{open}, R_{shorted} \} \in U $$
A general case can be stated by taking equation \ref{unitary_state_def} and making it a function thus.
\begin{equation} \begin{equation}
\label{atomic_def} \label{`unitarystate'_def}
Atomic(F) = \forall f \in F | active(f) \wedge f1 \in F \wedge f1 \neq f \wedge \neg active(f1) UnitaryState(F) = \forall f \in F | active(f) \wedge f1 \in F \wedge f1 \neq f \wedge \neg active(f1)
\end{equation} \end{equation}
%Which can be written
%$$ UnitaryState(FM(K)) $$
% should this be a paragraph in Symptom Abstraction ????

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\documentclass[a4paper,10pt]{article}
\usepackage{graphicx}
\usepackage{fancyhdr}
\usepackage{tikz}
\usepackage{amsfonts,amsmath,amsthm}
\input{style}
%\newtheorem{definition}{Definition:}
\begin{document}
\pagestyle{fancy}
\outerhead{{\small\bf Unitary State Failure Mode Sets}}
%\innerfoot{{\small\bf R.P. Clark } }
% numbers at outer edges
\pagenumbering{arabic} % Arabic page numbers hereafter
\author{R.P.Clark}
\title{Unitary State Failure Mode Sets}
\maketitle
\input{component_failure_modes_definition_paper}
\bibliographystyle{plain}
\bibliography{vmgbibliography,mybib}
\today
\end{document}