Mum speel checked/proof read

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Robin Clark 2010-11-28 20:16:09 +00:00
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%% What I have done %% What I have done
%% %%
This paper presents a simple two level Failure Mode Modular De-Composition (FMMD) This paper presents a simple two level Failure Mode Modular De-Composition (FMMD)
model of a theoretical System. model of a theoretical system.
Firstly a UML model is presented and the class relationships described. Firstly a UML model is presented and the class relationships described.
Secondly the theoretical model is developed and analysed. Secondly the theoretical model is developed and analysed.
This model is then represented as a Directed Acyclic Graph (DAG), This model is then represented as a Directed Acyclic Graph (DAG),
@ -39,7 +39,7 @@ if they have multiple causes.
This chapter This chapter
presents a simple two stage FMMD % Failure Mode Modular De-Composition (FMMD) presents a simple two stage FMMD % Failure Mode Modular De-Composition (FMMD)
model of a theoretical System. model of a theoretical system.
The Analysis model is then represented as a Directed Acyclic Graph (DAG), of the {\fg}s The Analysis model is then represented as a Directed Acyclic Graph (DAG), of the {\fg}s
components and failure modes represented in it. components and failure modes represented in it.
@ -71,7 +71,7 @@ We can start with some base components, of types C and K say, $\{ C_1, C_2, C_3
\input{./shortfm} \input{./shortfm}
\paragraph{Determing Failure Mode collections.} \paragraph{Determining Failure Mode collections.}
Thus applying the function $fm$ to any of the components Thus applying the function $fm$ to any of the components
gives error modes identified by a or b. gives error modes identified by a or b.
@ -109,18 +109,18 @@ the functional groups $FG^0_1$ and $FG^1_1$.
Also note that the component type $K$ has been used by Also note that the component type $K$ has been used by
two different functional groups. two different functional groups.
For the sake of example let our temperature environment For the sake of example, let our temperature environment
for the SYSTEM be ${{0}\oc}$ to ${{125}\oc}$, but let the component for the SYSTEM be ${{0}\oc}$ to ${{125}\oc}$, but let the component
type `K' have a de-graded performance failure mode between type `K' have a de-graded performance failure mode between
${{80}\oc}$ and ${{125}\oc}$\footnote{ A real world example of ${{80}\oc}$ and ${{125}\oc}$\footnote{ A real world example of
degraded performace with temperature is the isolating opto coupler. degraded performace with temperature is the isolating opto coupler.
These can typically only cope with lower baud rate ranges These can typically only cope with lower baud rate ranges
at high temperatures \cite{tlp181}.}. We can term this at high temperatures \cite{tlp181}.}. We can term this
degraded performce of component `K' as failure mode `d'. degraded performance of component `K' as failure mode `d'.
\paragraph{Symptom Extraction.} \paragraph{Symptom Extraction.}
A processes of symptom extraction is now applied to the functional groups. A process of symptom extraction is now applied to the functional groups.
Again for the sake of example, let us say that each functional Again for the sake of example, let us say that each functional
group has one or two symptoms again subscripted by $a$ and $b$. group has one or two symptoms again subscripted by $a$ and $b$.
@ -157,7 +157,7 @@ We must check this against all components used.
For our example, we component `K' which has an extra For our example, we component `K' which has an extra
failure mode for degraded performance `d'. Thus applying the function $fm$ failure mode for degraded performance `d'. Thus applying the function $fm$
to component type `K' under these temperature range conditions to component type `K' under these temperature range conditions
give the foillowing failure modes, $fm{K} =\{ K_a, K_b, K_d \}$. gives the following failure modes, $fm{K} =\{ K_a, K_b, K_d \}$.
Were our system specified for a ${{0}\oc}$ to ${{80}\oc}$ range Were our system specified for a ${{0}\oc}$ to ${{80}\oc}$ range
we could say $fm{K} =\{ K_a, K_b \}$. we could say $fm{K} =\{ K_a, K_b \}$.
@ -179,7 +179,7 @@ We can call these failures modes `symptoms'.
As this is a theoretical example, we shall have to skip this step\footnote{ As this is a theoretical example, we shall have to skip this step\footnote{
In a real analysis this would involve evaluating the effect of each components failure mode, (or combinations of) In a real analysis this would involve evaluating the effect of each components failure mode, (or combinations of)
on the performance of the {\fg}.}. on the performance of the {\fg}.}.
The next stage is to collect the common symptoms, or the symtoms that The next stage is to collect the common symptoms, or the symptoms that
are the same {\em from the perspective of a user of the {\fg}}. are the same {\em from the perspective of a user of the {\fg}}.
We can define this stage as the function $\bowtie$ which has a set of failure modes as We can define this stage as the function $\bowtie$ which has a set of failure modes as
its range and {\dc} as its domain. its range and {\dc} as its domain.
@ -203,7 +203,7 @@ as a directed acyclic graph (see figure \ref{fig:dag0}).
We can now create a new {\dc}. This will have an $\alpha$ value higher We can now create a new {\dc}. This will have an $\alpha$ value higher
than the any of the components in the {\fg} that it was derived from. than the any of the components in the {\fg} that it was derived from.
In this case all components were base components and therefore have an $\alpha$ value of zero. In this case all components were base components and therefore have an $\alpha$ value of zero.
Our derived component can thus take a n $\alpha$ value of one. Our derived component can thus take an $\alpha$ value of one.
Our newly derived component can be Our newly derived component can be
$$ DC^1_1 = \bowtie fm(FG^0_1) .$$ $$ DC^1_1 = \bowtie fm(FG^0_1) .$$
@ -234,7 +234,7 @@ UML OBJECT MODEL OF DERIVED COMPONENT TOO
\subsection{Using Derived Components in Functional Groups} \subsection{Using Derived Components in Functional Groups}
HERE should how the hierarchy is built, how the inheritance works etc HERE show how the hierarchy is built, how the inheritance works etc
HAVE an example. totally theoretical. HAVE Common mode failure detection AND Common dependency detection HAVE an example. totally theoretical. HAVE Common mode failure detection AND Common dependency detection

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\ifthenelse {\boolean{paper}} \ifthenelse {\boolean{paper}}
{ {
\paragraph{Failure Mode function $fm$.} \paragraph{Failure Mode function $fm$.}
We can definine a `failure modes' function $fm$ that has a functional group as its range We can define a `failure modes' function $fm$ that has a functional group as its range
and returns a set of failure modes as its domain. and returns a set of failure modes as its domain.
We now use this to determine the failure modes We now use this to determine the failure modes
in our functional groups. in our functional groups.