diff --git a/submission_thesis/CH4_FMMD/copy.tex b/submission_thesis/CH4_FMMD/copy.tex index ccbb21b..d2b7f85 100644 --- a/submission_thesis/CH4_FMMD/copy.tex +++ b/submission_thesis/CH4_FMMD/copy.tex @@ -598,11 +598,11 @@ This is represented in the DAG in figure \ref{fig:fg1adag}. \end{figure} -We can now formulate a `derived component' to represent this potential divider. -This can be named \textbf{PD}. +We can now formulate a `derived component' to represent this potential divider: +we name this \textbf{PD}. This {\dc} will have two failure modes. -We can use the symbol $\derivec$ to represent the process of taking the analysed -{\fg} and creating from it, a {\dc}. The creation of the {\dc} \textbf{PD} is +We use the symbol $\derivec$ to represent the process of taking the analysed +{\fg} and creating from it a {\dc}. The creation of the {\dc} \textbf{PD} is represented in figure~\ref{fig:dc1}. We then represent the {\dc} as a DAG in figure \ref{fig:dc1dag}. @@ -694,7 +694,7 @@ We can represent these failure modes on a DAG (see figure~\ref{fig:op1dag}). %} %\clearpage %\paragraph{Modelling the OP amp with the potential divider.} -We now merge the OP amp and the {\dc} {\em PD}, to +We now collect the OP amp and the {\dc} {\em PD}, to form a {\fg} to represent the non-inverting amplifier. % %We have the failure modes of the {\dc} for the potential divider, @@ -703,6 +703,7 @@ form a {\fg} to represent the non-inverting amplifier. %We can now create a {\fg} for the non-inverting amplifier %by bringing together the failure modes from \textbf{opamp} and \textbf{PD}. % +The two components in this new {\fg} have failure modes. Each of these failure modes will be given a {\fc} for analysis, and this is represented in table \ref{tbl:ampfmea1}. @@ -871,7 +872,7 @@ and this is represented in table \ref{tbl:ampfmea1}. %amplification characteristics from FS2 and FS6 can be considered as low output from the OPAMP for the application %in hand (say milli-volt signal amplification). -For this amplifier configuration we have three failure modes; {\em AMP\_High, AMP\_Low, LowPass}.%see figure~\ref{fig:fgampb}. +For this amplifier configuration we have three failure modes; {\em AMP\_High, AMP\_Low, LowPass}. % see figure~\ref{fig:fgampb}. This model now has two stages of analysis hierarchy, as represented in figure~\ref{fig:dc2}. From the analysis in table \ref{tbl:ampfmea1} we can create the {\dc} {\em NONINVAMP}, which represents the failure mode behaviour of the non-inverting amplifier. @@ -884,11 +885,15 @@ represents the failure mode behaviour of the non-inverting amplifier. \label{fig:dc2} \end{figure} -We can now examine the {\dc} {\em INVAMP} by drawing it as a DAG. +We can now examine the failure mode relationships in the {\dc} {\em INVAMP} by drawing it as a DAG. %expand the {\em PD} {\dc} and have a full FMMD failure %mode %model -We can traverse this DAG, and thus determine all possible causes for +We can traverse this DAG, tracing the top level symptoms down to the leaves of the tree (the leaves being {\bc} failure modes), +and thus determine all possible causes for the three high level symptoms, i.e. the failure~modes of the non-inverting amplifier {\em INVAMP}. +Knowing all possible causes for a top level event/failure~mode +is extremely useful. Were the top level event to be classified as catastrophic for instance, we could use this information +to strengthen components that could cause the top level event/failure. % Figure \ref{fig:noninvdag1} shows a fully expanded DAG, from which we can derive information to assist in building models for FTA, FMEA, FMECA and FMEDA failure mode analysis methodologies. @@ -999,7 +1004,7 @@ It could be something %quite complicated like an %integrated micro-controller, or quite simple like the resistor. % -We can define a +We can identify a component by its name, a manufacturer's part number and perhaps a vendor's reference number. @@ -1017,8 +1022,8 @@ We, in fact, need to go a little further than the above definition of a part, and say that we want to define an atomic entity. % used as a building block. %The term component, in American English, can mean a building block or a part. %In British-English a component generally is given to mean the definition for part above. -We define {\bc} to be the lowest level of component that we use as a building block. -This is a choice made by the analyst. +We define {\bc} to be the lowest level---or entities we begin with in our analysis---of component that we use as a building block. +This is a choice made by the analyst, often guided by the standards to which the analysis is being performed to. % Both op-amps and transistors have published statistical failure rates and yet an op-amp is constructed from transistors. % @@ -1036,7 +1041,7 @@ to which we are approving/analysing a system. %% FUCKING STEREO SUB_SYSTEM EXAMPLE, THE FUCKING CHILDRENS SECTION -\subsection{Systems, functional groupings, components and failure modes: sound system example} +\subsection{definition of terms: sound system example.} %000000elpful here to define the terms, `system', `functional~group', `component', `base~component', `symptom' and `derived~component/sub-system'. %These are listed in table~\ref{tab:symexdef}. @@ -1051,7 +1056,7 @@ This is now used as an example to describe terms used in FMMD. % For instance a stereo amplifier separate/slave is a component. %The -whole sound system consists perhaps of the following `components': +A whole sound system consists perhaps of the following components: CD-player, tuner, amplifier~separate, loudspeakers and ipod~interface. %Thinking like this is a top~down analysis approach @@ -1084,9 +1089,10 @@ These collections are termed `{\fgs}'. % For instance, the circuitry that powers the laser diode to illuminate the CD might contain a handful of components, and as such would make a good candidate -as one of the base level {\fgs}. +as one of the base level {\fgs}. It is a good candidate because +it performs a well defined function and it could be considered a design module. -\paragraph{Functional group to {\dc} process outline.} +\paragraph{Functional grouping to {\dc} process outline.} %In choosing the lowest level (base component) sub-systems we would look %for the smallest `functional~groups' of components within a system. We can define a {\fg} as a set of components that interact @@ -1151,7 +1157,7 @@ Currently, failure mode information is generally only available for generic com % number of well defined ways. For common {\bcs} there is established literature for the failure modes for the system designer to consider (often with accompanying statistical -failure rates)~\cite{mil1991}~\cite{en298}~\cite{fmd91}. +failure rates)~\cite{mil1991,en298,fmd91}. % For instance, a simple resistor is generally considered to fail in two ways, it can go open circuit or it can short. @@ -1318,13 +1324,13 @@ A flat set is a set containing just failure modes and not sets of failure modes~ %for the {\fg}. % Each of these failure modes, and optionally combinations of them, are -formed into `test~cases' which are +formed into failure~scenarios which are analysed for their effect on the failure mode behaviour of the `{\fg}'. % Once we have the failure mode behaviour of the {\fg}, we can determine its symptoms of failure. %for the {\fg}. % -We could term these symptoms the derived failure modes of the `{\fg}'. +We view these symptoms as derived failure modes of the {\fg}. % Or in other words we can determine how the `{\fg}' can fail. We can now consider the {\fg} as a {\dc} % sort of super component @@ -1337,8 +1343,7 @@ The process for taking a {\fg}, analysing its failure mode behaviour, considerin all the failure modes of all the components in the group and collecting symptoms of failure, is termed `symptom abstraction'. % -This -is dealt with in detail using an algorithmic description, in appendix \ref{sec:algorithmfmmd}. +This is dealt with in detail using an algorithmic description, in appendix \ref{sec:algorithmfmmd}. % % define difference between a \fg and a \dc diff --git a/submission_thesis/CH4_FMMD/dc1.dia b/submission_thesis/CH4_FMMD/dc1.dia index ad29f82..c56cc7b 100644 Binary files a/submission_thesis/CH4_FMMD/dc1.dia and b/submission_thesis/CH4_FMMD/dc1.dia differ diff --git a/submission_thesis/CH4_FMMD/dc2.dia b/submission_thesis/CH4_FMMD/dc2.dia index 56c0ffb..152c56f 100644 Binary files a/submission_thesis/CH4_FMMD/dc2.dia and b/submission_thesis/CH4_FMMD/dc2.dia differ