As sent to JMC for english pr

This commit is contained in:
Robin Clark 2012-09-09 10:50:04 +01:00
parent f9d7a41ce8
commit a55aa9698d
3 changed files with 39 additions and 10 deletions

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@ -156,7 +156,7 @@ Database
number = "", number = "",
pages = " ", pages = " ",
year = "2012", year = "2012",
note = "Proceedings of the First International Workshop on Euler Diagrams (Euler 2004)", note = " ",
issn = "1571-0661", issn = "1571-0661",
doi = "DOI: 10.1016/j.entcs.2005.02.018", doi = "DOI: 10.1016/j.entcs.2005.02.018",
url = "http://www.bsigroup.com/en/assessment-and-certification-services/management-systems/standards-and-schemes/iso-9001/", url = "http://www.bsigroup.com/en/assessment-and-certification-services/management-systems/standards-and-schemes/iso-9001/",

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@ -1223,6 +1223,18 @@ We can thus create a new component derived from analysing the {\fg} where
% %
the symptoms of failure of the {\fg} are the failure modes of this new `{\dc}'. the symptoms of failure of the {\fg} are the failure modes of this new `{\dc}'.
An outline of the FMMD process is itemised below:
\begin{itemize}
\item Collect components to form a {\fg},
\item Create failure cause `test~cases' for all failure modes of the components within the {\fg},
\item Analyse the effect of all the test~cases on the operation of the {\fg},
\item Determine the common failure modes of the {\fg},
\item Create and name a derived component for the {\fg},
\item Assign the common failure modes from the {\fg} as the failure modes of the {\dc}.
\end{itemize}
%We can now call our functional~group a sub-system or a derived~component. %We can now call our functional~group a sub-system or a derived~component.
%The goal here is to know how it will behave under fault conditions ! %The goal here is to know how it will behave under fault conditions !
%Imagine buying one such `sub~system' from a very honest vendor. %Imagine buying one such `sub~system' from a very honest vendor.
@ -1297,8 +1309,11 @@ The UML class diagram in figure
structure with its associated failure modes. structure with its associated failure modes.
% %
From this diagram we see that each component must have at least one failure mode. From this diagram we see that each component must have at least one failure mode.
%
To clearly show that the failure modes are mutually exclusive states, or unitary states associated with one component, To clearly show that the failure modes are mutually exclusive states, or unitary states associated with one component,
each failure mode is referenced back to only one component. This constraint is discussed in detail in section~\ref{sec:unitarystate}. each failure mode is referenced back to only one component.
%
This constraint is discussed in detail in section~\ref{sec:unitarystate}.
%%-%% MTTF STATS CHAPTER MAYBE ?? %%-%% MTTF STATS CHAPTER MAYBE ??
%%-%% %%-%%
@ -2156,6 +2171,7 @@ we can ensure that all these {\fms} are traceable to subsequent {\dc} {\fms}
in the model. in the model.
% %
With the above condition true, we term this a `complete' FMMD failure model. With the above condition true, we term this a `complete' FMMD failure model.
Ensuring this condition is described in section~\ref{sec:completetest}.
\paragraph{State explosion problem of FMEA solved by FMMD.} \paragraph{State explosion problem of FMEA solved by FMMD.}
% %
@ -2164,18 +2180,22 @@ the traditional state explosion problem in FMEA, where each failure
mode could be considered in the context of all other components in the system mode could be considered in the context of all other components in the system
disappears. disappears.
% %
This is dealt with formally in section~\ref{sec:cc}. This issue addressed formally in section~\ref{sec:cc}.
\paragraph{Uses of the FMMD failure mode model.} \paragraph{Uses of the FMMD failure mode model.}
% %
Having a failure mode graph/model, where base component failure modes are traceable to top event events, Having a failure mode graph/model, where base component failure modes are traceable to top event events,
provides a forward search derived failure mode model. provides a forward search derived failure mode model.
A forward search means that we can apply checks to ensure that
all known component failure
modes have been considered in the analysis (i.e. completeness as described above).
% %
%A forward search means that we can apply checks to ensure that This means that for every system level failure we can track back to possible causes
%all known component failure in the base components. Coupled with MTTF statistics for the base components
%modes have been considered in the analysis (i.e. completeness as described above). this allows use to predict statistical failure rates for system level failures (this is
described in greater detail in section~\ref{sec:determine_fms}).
% %
We can use this model to derive information We can also use the FMMD model to derive information
to assist in creating related models such as FTA~\cite{nucfta,nasafta}, to assist in creating related models such as FTA~\cite{nucfta,nasafta},
traditional FMEA, FMECA~\cite{safeware}[p.344], FMEDA~\cite{scsh}, diagnostics schemas~\cite{dbamafta} traditional FMEA, FMECA~\cite{safeware}[p.344], FMEDA~\cite{scsh}, diagnostics schemas~\cite{dbamafta}
and other failure mode analysis methodologies. and other failure mode analysis methodologies.

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@ -806,9 +806,18 @@ given by
$$ dtc(F) = TC $$ $$ dtc(F) = TC $$
In algorithm \ref{alg22}, the function \textbf{chosen} means that the failure modes for a particular test case have been chosen by In algorithm \ref{alg22}, the function \textbf{chosen} means that
a human operator and are additional to those chosen by the automated process (i.e they are special case test cases involving multiple failure modes) the failure modes for a particular test case have been chosen by
The function \textbf{unitary state} means that all test cases can have no pairs of failure modes sourced from the same component. a human operator and are additional to those chosen by the automated process (i.e they are
special case test cases involving multiple failure modes)
The function \textbf{unitary state} means that all test
cases can have no pairs of failure modes sourced from the same component.
\label{sec:completetest}
This function also ensure completeness in the model.
It ensures that for all failure modes in the {\fg} are considered in a test~case.
\ifthenelse {\boolean{paper}} \ifthenelse {\boolean{paper}}
{ {
%% perhaps ref a paper here XXXXX %% perhaps ref a paper here XXXXX