From 246e2eea203046bb6f8d1ff6581b45c44deddc3e Mon Sep 17 00:00:00 2001 From: Robin Clark Date: Mon, 27 Jun 2011 09:24:42 +0100 Subject: [PATCH] ... --- .../System_safety_2011/submission.tex | 75 ++++++++++--------- 1 file changed, 38 insertions(+), 37 deletions(-) diff --git a/fmmd_concept/System_safety_2011/submission.tex b/fmmd_concept/System_safety_2011/submission.tex index aed504f..4482ab1 100644 --- a/fmmd_concept/System_safety_2011/submission.tex +++ b/fmmd_concept/System_safety_2011/submission.tex @@ -13,7 +13,8 @@ \newcommand{\fc}{\em fault scenario} \newcommand{\fcs}{\em fault scenarios} \date{} - +\renewcommand{\encodingdefault}{T1} +\renewcommand{\rmdefault}{tnr} %\newboolean{paper} %\setboolean{paper}{true} % boolvar=true or false @@ -71,8 +72,8 @@ failure mode of the component or sub-system}}} %\nodate \maketitle -\paragraph{Keywords:} FMMD FTA FMEA static failure mode modelling safety critical -\small +\paragraph{Keywords:} static failure mode modelling safety-critical +%\small \abstract{ \em { The certification process of safety critical products for European and @@ -174,7 +175,7 @@ can reveal. %\subsection{Bottom-up approach: } -\paragraph{State Explosion problem for FMEA, FMECA, FMEDA.} +%\paragraph{State Explosion problem for FMEA, FMECA, FMEDA.} The bottom-up techniques all suffer from % a problem of state explosion. To perform the analysis rigorously, we would need to consider the effect @@ -184,9 +185,9 @@ and operational states further increases this effect. Let $N$ be the number of components in our system, and $K$ be the average number of component failure modes (ways in which a component can fail). The approximate total number of base component failure modes is $N \times K$. To examine the effect that one failure mode has on all -the other components\footnote{A %base -component failure will typically affect the sub-system -it is part of, and create a failure effect at the system level.} +the other components %\footnote{A %base +%component failure will typically affect the sub-system +%it is part of, and create a failure effect at the system level.} will be $(N-1) \times N \times K$. %, in effect a very large set cross product. If $E$ is the number of environmental conditions to consider in a system, and $A$ the number of applied/operational states (or modes of the system), @@ -245,7 +246,7 @@ From the deficiencies outlined above, ideally we can form a set of desirable cr \label{fmmdreq} \item Address the state explosion problem. % 1 \item Ensure that all component failure modes be considered in the model. % 2 -\item Be easy to integrate mechanical, electronic and software models \cite{sccs}[pp.287]. %3 +\item Be easy to integrate mechanical, electronic and software models \cite{sccs}[p.287]. %3 \item Be modular, in that commonly used {\fgs} can be re-used in other designs/projects. %4 \item It should have a formal basis, that is to say, be able to produce mathematical traceability %5 for its results, such as error causation trees.%, reliability and safety statistics. @@ -433,7 +434,7 @@ As an example, we consider a standard non-inverting op amp~\cite{aoe}[p.234], s \begin{figure}[h+] \centering - \includegraphics[width=150pt,keepaspectratio=true]{../../noninvopamp/noninv.png} + \includegraphics[width=100pt,keepaspectratio=true]{../../noninvopamp/noninv.png} % noninv.jpg: 341x186 pixel, 72dpi, 12.03x6.56 cm, bb=0 0 341 186 \caption{Standard non inverting amplifier configuration} \label{fig:noninvamp} @@ -597,7 +598,7 @@ we can show the relationships between the component failure modes and resultant %The {\fg} can now be considered a derived component. This is represented in the DAG in figure \ref{fig:fg1adag}. -\begin{figure}[h+] +\begin{figure}[h] \centering \begin{tikzpicture}[shorten >=1pt,->,draw=black!50, node distance=\layersep] \tikzstyle{every pin edge}=[<-,shorten <=1pt] @@ -607,14 +608,14 @@ This is represented in the DAG in figure \ref{fig:fg1adag}. \tikzstyle{symptom}=[fmmde, fill=blue!50]; \tikzstyle{annot} = [text width=4em, text centered] - \node[component] (R1) at (0,-4) {$R_1$}; - \node[component] (R2) at (0,-6) {$R_2$}; + \node[component] (R1) at (0,-0.7) {$R_1$}; + \node[component] (R2) at (0,-1.9) {$R_2$}; - \node[failure] (R1SHORT) at (\layersep,-2) {$R1_{SHORT}$}; - \node[failure] (R1OPEN) at (\layersep,-4) {$R1_{OPEN}$}; + \node[failure] (R1SHORT) at (\layersep,-0) {$R1_{Sh}$}; + \node[failure] (R1OPEN) at (\layersep,-1.2) {$R1_{Op}$}; - \node[failure] (R2SHORT) at (\layersep,-6) {$R2_{SHORT}$}; - \node[failure] (R2OPEN) at (\layersep,-8) {$R2_{OPEN}$}; + \node[failure] (R2SHORT) at (\layersep,-2.5) {$R2_{Sh}$}; + \node[failure] (R2OPEN) at (\layersep,-3.8) {$R2_{Op}$}; \path (R1) edge (R1SHORT); \path (R1) edge (R1OPEN); @@ -624,8 +625,8 @@ This is represented in the DAG in figure \ref{fig:fg1adag}. % Potential divider failure modes % - \node[symptom] (PDHIGH) at (\layersep*2,-4) {$PD_{HIGH}$}; - \node[symptom] (PDLOW) at (\layersep*2,-6) {$PD_{LOW}$}; + \node[symptom] (PDHIGH) at (\layersep*2,-0.7) {$PD_{HIGH}$}; + \node[symptom] (PDLOW) at (\layersep*2,-2.2) {$PD_{LOW}$}; \path (R1OPEN) edge (PDHIGH); \path (R2SHORT) edge (PDHIGH); @@ -768,12 +769,12 @@ We can represent these failure modes on a DAG (see figure~\ref{fig:op1dag}). \tikzstyle{symptom}=[fmmde, fill=blue!50]; \tikzstyle{annot} = [text width=4em, text centered] - \node[component] (OPAMP) at (0,-2.3) {$OPAMP$}; + \node[component] (OPAMP) at (0,-1.8) {$OPAMP$}; - \node[failure] (OPAMPLU) at (\layersep,-0) {latchup}; - \node[failure] (OPAMPLD) at (\layersep,-1.5) {latchdown}; - \node[failure] (OPAMPNP) at (\layersep,-2.9) {noop}; - \node[failure] (OPAMPLS) at (\layersep,-4.1) {lowslew}; + \node[failure] (OPAMPLU) at (\layersep,-0) {l-up}; + \node[failure] (OPAMPLD) at (\layersep,-1.2) {l-dn}; + \node[failure] (OPAMPNP) at (\layersep,-2.4) {noop}; + \node[failure] (OPAMPLS) at (\layersep,-3.6) {lowslew}; \path (OPAMP) edge (OPAMPLU); \path (OPAMP) edge (OPAMPLD); @@ -990,9 +991,9 @@ to assist in building models for FTA, FMEA, FMECA and FMEDA failure mode analysi % This is the same as writing \foreach \name / \y in {1/1,2/2,3/3,4/4} % \node[component, pin=left:Input \#\y] (I-\name) at (0,-\y) {}; - \node[component] (OPAMP) at (0,-2.8) {$OPAMP$}; - \node[component] (R1) at (0,-7) {$R_1$}; - \node[component] (R2) at (0,-10) {$R_2$}; + \node[component] (OPAMP) at (0,-1.8) {$OPAMP$}; + \node[component] (R1) at (0,-6) {$R_1$}; + \node[component] (R2) at (0,-7.6) {$R_2$}; %\node[component] (C-3) at (0,-5) {$C^0_3$}; %\node[component] (K-4) at (0,-8) {$K^0_4$}; @@ -1004,16 +1005,16 @@ to assist in building models for FTA, FMEA, FMECA and FMEDA failure mode analysi %\foreach \name / \y in {1,...,5} % \path[yshift=0.5cm] - \node[failure] (OPAMPLU) at (\layersep,-0) {latchup}; - \node[failure] (OPAMPLD) at (\layersep,-1.6) {latchdown}; - \node[failure] (OPAMPNP) at (\layersep,-3.2) {noop}; - \node[failure] (OPAMPLS) at (\layersep,-4.4) {lowslew}; + \node[failure] (OPAMPLU) at (\layersep,-0) {l-up}; + \node[failure] (OPAMPLD) at (\layersep,-1.3) {l-dn}; + \node[failure] (OPAMPNP) at (\layersep,-2.6) {noop}; + \node[failure] (OPAMPLS) at (\layersep,-3.9) {lowslew}; - \node[failure] (R1SHORT) at (\layersep,-6.0) {$R1_{SHORT}$}; - \node[failure] (R1OPEN) at (\layersep,-7.6) {$R1_{OPEN}$}; + \node[failure] (R1SHORT) at (\layersep,-5.2) {$R1_{Sh}$}; + \node[failure] (R1OPEN) at (\layersep,-6.5) {$R1_{Op}$}; - \node[failure] (R2SHORT) at (\layersep,-9.2) {$R2_{SHORT}$}; - \node[failure] (R2OPEN) at (\layersep,-10.7) {$R2_{OPEN}$}; + \node[failure] (R2SHORT) at (\layersep,-7.8) {$R2_{Sh}$}; + \node[failure] (R2OPEN) at (\layersep,-9.1) {$R2_{Op}$}; @@ -1037,8 +1038,8 @@ to assist in building models for FTA, FMEA, FMECA and FMEDA failure mode analysi % Potential divider failure modes % - \node[symptom] (PDHIGH) at (\layersep*2,-7) {$PD_{HIGH}$}; - \node[symptom] (PDLOW) at (\layersep*2,-9) {$PD_{LOW}$}; + \node[symptom] (PDHIGH) at (\layersep*2,-6) {$PD_{HIGH}$}; + \node[symptom] (PDLOW) at (\layersep*2,-7.6) {$PD_{LOW}$}; @@ -1240,7 +1241,7 @@ failure modes, with each step annotated as {\fcs}, the model is easier to mainta %\today % -{ \tiny +{ %\tiny %\footnotesize \bibliographystyle{plain} \bibliography{vmgbibliography,mybib} }