arrg git and its helpful error messages

component_failure_modes_definition/component_failure_modes_definition.tex

@@ -1,6 +1,6 @@
 
 \abstract{ This chapter defines what is meant by the terms
-components, component fault modes and `unitary~state' component fault modes.
+components, derived~components, functional~groups, component fault modes and `unitary~state' component fault modes.
 %The application of Bayes theorem  in current methodologies, and
 %the suitability of the `null hypothesis' or `P' value statistical approach
 %are discussed.
@@ -62,7 +62,10 @@ From this diagram we see that each component must have at least one failure mode
 Also to clearly show that the failure modes are unique events associated with one component,
 each failure mode is referenced back to only one component. 
 This modelling constraint is due to the fact that even generic components with the same 
-failure mode types, will have different statistical MTTF properties within the same circuitry.
+failure mode types, may have different statistical MTTF properties within the same 
+circuitry\footnote{For example, consider resistors one of high resistance and one low.
+The generic failure modes for a resistor will be the same for both.
+The lower resistance part will draw more current and therefore have a statistically higher chance of failure.}.
 %% sharing failure modes arrrgghh so irrelevant
 %% wrong as well perhaps, as each component will have environmental constraints
 %% that determine its statistical behaviour. A 1 Meg ohm resistor
@@ -85,11 +88,12 @@ as shown in figure \ref{fig:componentpl}.
  \label{fig:componentpl}
 \end{figure}
 
-Parts in the parts list (bought in parts) will be termed `base~comonents'.
-Parts derived from base~components may not require parts numbers, and will
+Components in the parts list (bought in parts) will be termed `base~comonents'.
+Components derived from base~components may not require 
+parts~numbers\footnote{It is common practise for sub assemblies, PCB's, mechanical parts,
+software modules and some collections of components to have part numbers}, and will
 not require a vendor reference, but must be named.
 
-
  
 
 %%
@@ -108,7 +112,7 @@ Another top down technique is to apply cost benifit analysis
 to determine which faults are the highest priority to fix\cite{FMEA}.
 The aim of FMMD analysis is to produce complete  failure
 models of safety critical systems  from the bottom-up,
-starting, where possible with known component failure modes.
+starting, where possible with known base~component failure~modes.
 
 An advantage of working from the bottom up is that we can ensure that
 all component failure modes must be considered. A top down approach
@@ -120,15 +124,19 @@ work together to perform a simple function.
 The components to include in a  functional group are chosen by a human, the analyst.
 %We can represent the `Functional~Group' as a class. 
  When we have a 
-`Functional~Group' we can look at the failure modes of all the components
-in it.
+`Functional~Group' we can look at the components it contains,
+and from this determine the failure modes of all the components that belong to it.
+%
 % and determine a failure mode model for that group.
-The `Functional~Group' is seen by the analyst as a collection of component failures modes.
+The `Functional~Group' as used by the analyst is a collection of component failures modes.
 Each of these failure modes, and optionally combinations of them, are
 analsyed for their effect on the failure mode behaviour of the `Functional~Group'.
-From this we can determine a new set of failure modes, the failure modes of the 
-Or in other words we can determine the failure modes of the `Functional~Group'.
-group. We can now consider the functional group as a sort of super component
+%
+From this we can determine a new set of failure modes, the failure modes of the
+`Functional~Group'.
+% 
+Or in other words we can determine how the `Functional~Group' can fail.
+We can now consider the functional group as a sort of super component
 with a known set of failure modes.
 
 
@@ -157,6 +165,12 @@ fault behaviour.
 The UML representation shows a `functional group' having a one to one relationship with a derived~component.
 We can represent this using an UML diagram in figure \ref{fig:cfg}.
 
+Using the symbol $\bowtie$ to indicate the analysis process that takes a
+functional group and converts it into a new component.
+
+$$ \bowtie ( FG ) \mapsto DerivedComponent $$
+
+
 \begin{figure}[h]
  \centering
  \includegraphics[width=400pt,bb=0 0 712 286,keepaspectratio=true]{component_failure_modes_definition/cfg.jpg}
@@ -165,12 +179,6 @@ We can represent this using an UML diagram in figure \ref{fig:cfg}.
  \label{fig:cfg}
 \end{figure}
 
-Using the symbol $\bowtie$ to indicate an analysis process that takes a
-functional group and converts it into a new component.
-
-$$ \bowtie ( FG ) \mapsto DerivedComponent $$
-
-
 
 \subsection{Keeping track of the derived \\ components position in the hierarchy}
 
@@ -235,15 +243,16 @@ This corresponds to the `mutually exclusive' definition in
 probability theory\cite{probandstat}.
 \end{definition}
 
-We can define a function $FM()$ to 
-take a given component $K$ and return its set of failure modes $F$.
+We can define a function $FM$ to 
+take a given component $C$ and return its set of failure modes $F$.
 
-$$  FM : K \mapsto F $$
+$$  FM : C \mapsto F $$
 
-We can further define a set $U$ which is a set of sets of failure modes, where
+\begin{definition}
+We can 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 $F \in U$.
-
+\end{definition}
 
 \section{Component failure modes:\\ Unitary State example}
 

thesis.tex

@@ -54,7 +54,7 @@
 \input{standards/standards}
 
 \chapter{Statistical Methods and Models}
-%\input{statistics/statistics}
+\input{statistics/statistics}
 
 \chapter{Survey of Safety Critical Analysis Methodologies and Tools Available}
 \input{survey/survey}