From 99c751c966a35d3ee6a826ef050d1085eddd4af9 Mon Sep 17 00:00:00 2001 From: Robin Clark Date: Mon, 14 Feb 2011 09:32:34 +0000 Subject: [PATCH] nr compiles as thesis now --- nr/nr.tex | 6 ++++++ survey/survey.tex | 21 +++++++++++++-------- 2 files changed, 19 insertions(+), 8 deletions(-) diff --git a/nr/nr.tex b/nr/nr.tex index 9b30566..f7d655c 100644 --- a/nr/nr.tex +++ b/nr/nr.tex @@ -75,6 +75,8 @@ Assume resistors not from same batch. Show how parameter change is cancelled out, use sum of squares statistics to show by how much. +\ifthenelse {\boolean{paper}} +{ \begin{figure} \begin{tikzpicture}[line width=1pt] \draw (0,0) -- ++(0,1cm); @@ -118,3 +120,7 @@ to show by how much. \end{tikzpicture} \caption{A `network resistor'} \end{figure} +} +{ +electComp not in main thesis director yet +} diff --git a/survey/survey.tex b/survey/survey.tex index 1e6c8a7..8cca48e 100644 --- a/survey/survey.tex +++ b/survey/survey.tex @@ -266,6 +266,8 @@ of corrective action. \item Possibility to miss the effects of failure modes at SYSTEM level. \item Possibility to miss environmental effects. \item No possibility to model base component level double failure modes. +\item Does not model component failure modes +that may cause more than one type of SYSTEM failure. \end{itemize} \paragraph{Note.} FMEA is sometimes used in its literal sense, that is to say @@ -383,6 +385,8 @@ The $C_r$ value, for a given serverity $s$ is calculated thus under which the equipment is operating. \item Possibility to miss environmental affects. \item No possibility to model base component level double failure modes. +\item As with all failure mode methodologies based on FMEA, does not model component failure modes +that may cause more than one type of SYSTEM failure. \end{itemize} @@ -495,10 +499,11 @@ $\lambda_{SD}$, $\lambda_{SU}$, $\lambda_{DD}$, $\lambda_{DU}$). These new failures are added to the model. %SD, SU, DD, DU. -\glossary{name={SD},description={Safe Detected; a SYSTEM level failure mode that is considered safe, and is detected by self checking mechanisms}} -\glossary{name={SU},description={Safe Undetected; a SYSTEM level failure mode that is considered safe, and is not detected by self checking mechanisms}} -\glossary{name={DD},description={Dangerous Detected; a SYSTEM level failure mode that is considered dangerous, and is detected by self checking mechanisms}} -\glossary{name={DU},description={Dangerous Undetected; a SYSTEM level failure mode that is considered dangerous, and is not detected by self checking mechanisms}} + +\glossary{name={SU},description={Safe Undetected; a SYSTEM level failure mode that is considered safe, and is not detected by self checking mechanisms. See FMEDA~\cite{en61508}}} +\glossary{name={SD},description={Safe Detected; a SYSTEM level failure mode that is considered safe, and is detected by self checking mechanisms. See FMEDA~\cite{en61508}}} +\glossary{name={DD},description={Dangerous Detected; a SYSTEM level failure mode that is considered dangerous, and is detected by self checking mechanisms. See FMEDA~\cite{en61508}}} +\glossary{name={DU},description={Dangerous Undetected; a SYSTEM level failure mode that is considered dangerous, and is not detected by self checking mechanisms. See FMEDA~\cite{en61508}}} With these classifications, and statistics for each component we can now calculate statistics for the diagnostic coverage (how good at `self checking' the system is) @@ -590,14 +595,12 @@ With one component failure mode per row, all the statistical factors for SIL rating can be produced\footnote{A SIL rating will apply to an installed plant, i.e. a complete installed and working SYSTEM. SIL ratings for individual components or sub-systems are meaningless, and the nearest equivalent would be the FIT/PFD and SFF and diagnostic coverage figures.}. + + \glossary{name={FIT}, description={Failure in Time (FIT). The number of times a particular failure is expected to occur in a $10^{9}$ hour time period.}} - - - - \subsubsection{FMEDA and failure outcome prediction accuracy.} FMEDA suffers from the same problems of lack of component failure mode outcome prediction accuracy, as FMEA in section \ref{pfmea}. @@ -651,6 +654,8 @@ and its international analog standard IOC5108. \item Statistical nature allows a proportion of undetected failures for given S.I.L. level. \item Allows a small proportion of `undetectable' error conditions. \item No possibility to model base component level double failure modes. +\item As with all failure mode methodologies based on FMEA, does not model component failure modes +that may cause more than one type of SYSTEM failure. \end{itemize} %AND then how we can solve all there problems