From dcad10e83d852a68a5a6a56918b928343371ebb5 Mon Sep 17 00:00:00 2001 From: Robin Date: Sun, 25 Apr 2010 12:40:03 +0100 Subject: [PATCH] 25APR2010 --- introduction/introduction.tex | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/introduction/introduction.tex b/introduction/introduction.tex index 839dd8e..2ba8a7a 100644 --- a/introduction/introduction.tex +++ b/introduction/introduction.tex @@ -9,12 +9,16 @@ the design of safety critical systems. The initial motivation for this study was to create a system applicable to industrial burner controllers. The methodology developed was designed to cope with -both the specific `simultaneous failures'\cite{EN298},\cite{EN230},\cite{EN12067} -and the probability to dangerous fault approach\cite{EN61508}. +both the +deterministic +and +probablistic approaches. +%specific `simultaneous failures'\cite{EN298},\cite{EN230},\cite{EN12067} +%and the probability to dangerous fault approach\cite{EN61508}. The visual notation developed was initially designed for electronic fault modelling. -However, it was relaised that could be applied to mechanical and software domains as well. -This changed the target for the study slightly to encompass these domains in a common notation. +However, it was realised that could be applied to mechanical and software domains as well. +This changed the target for the study slightly to encompass these three domains in a common notation. \section{Background} @@ -216,11 +220,15 @@ This was an X-ray dosage machine, that, due to software errors caused the deaths of several patients and injured more during the 1980's. The Therac-25 was a designed from a manual system, which had checks and interlocks, and was computerised. Software bugs were the primnary causes of the radiation -overdoses. +overdoses. \cite{therac} Any new safety critical analysis methodology should be able to model software, electrical and hardware faults using a common notation. +Ideally the tool should be automated so that it can +seamlessly analyse the entire system, and apply +rigorous checking to ensure that no +fault conditions are missed. % http://en.wikipedia.org/wiki/Autopilot