diff --git a/mybib.bib b/mybib.bib index d19b719..cec5374 100644 --- a/mybib.bib +++ b/mybib.bib @@ -1,3 +1,11 @@ +@INPROCEEDINGS{probfmea_4338247, +author={Grunske, Lars and Colvin, R. and Winter, K.}, +booktitle={Quantitative Evaluation of Systems, 2007. QEST 2007. Fourth International Conference on the}, title={Probabilistic Model-Checking Support for FMEA}, +year={Sept.}, +pages={119-128}, +keywords={fault diagnosis;formal verification;probability;system monitoring;effect analysis;failure mode;probabilistic fault injection;probabilistic model checking;Accidents;Australia;Cause effect analysis;Failure analysis;Hazards;Information analysis;Information technology;Probability;Risk analysis;Safety;Failure Mode;Probabilistic Model Checking;System Safety;and Effect Analysis}, +doi={10.1109/QEST.2007.18},} + @article{parnas1991assessment, title={Assessment of safety-critical software in nuclear power plants.}, diff --git a/related_papers_books/probablistic_modelchecking_support_FMEA_04338247.pdf b/related_papers_books/probablistic_modelchecking_support_FMEA_04338247.pdf new file mode 100644 index 0000000..9c45fb8 Binary files /dev/null and b/related_papers_books/probablistic_modelchecking_support_FMEA_04338247.pdf differ diff --git a/submission_thesis/CH2_FMEA/copy.tex b/submission_thesis/CH2_FMEA/copy.tex index 28be3c8..32f3234 100644 --- a/submission_thesis/CH2_FMEA/copy.tex +++ b/submission_thesis/CH2_FMEA/copy.tex @@ -608,6 +608,20 @@ because we can usually find Mean Time to Failure (MTTF) statistics for commonly Also, used in the design phase of a project, FMEA is a useful tool for discovering potential failure scenarios~\cite{1778436820050601}. % +From a whole system perspective, we may find that {\bc} {\fms} +may have more than one possible system event associated with them. +Often there will be a clear one to one mapping, but +probabilities to failure (as used in FMECA) +could mean one to many.% mapping. +% +We could represent a failure mode and its possible outcomes using a Markov chain~\cite{probfmea_4338247}. +% +Where multiple simultaneous\footnote{Multiple simultaneous failures are taken to mean failures that occur within the same detection period.} +failure modes are considered this complicates +the statistical nature of the Markov chain, cause effect model. +% +What we in fact get is the merging of two Markov chains +for our cause effect model. % Subject Object Wiki answers : Best Answer %It is not grammar or vocabulary. It is a philosophical reference. %The dichotomy is the surrounding view of self that we act out of. It is often learned with language and not taught [like the alphabet and numbers are taught] in early life through language and the forming of distinctions. @@ -628,17 +642,28 @@ the subjective sense can we determine its meaning and/or severity. It is worth remembering that failure mode analysis performed on the leaks possible from the O ring on the space shuttle did not link this failure to the catastrophic failure of the spacecraft~\cite{challenger,sanjeev}. +% This was not a failure in the objective reasoning, but more of the subjective, or the context in which the leak occurred. % +What this means is that for an objectively calculated failure mode outcome, we may have +more than one subjective outcome definition for it. + +\paragraph{Multiple Simultaneous Failure Modes} +% FMEA is less useful for determining events for multiple -simultaneous\footnote{Multiple simultaneous failures are taken to mean failures that occur within the same detection period.} +simultaneous failures. % Work has been performed using component failure statistics to offer the more likely multiple failures~\cite{FMEAmultiple653556} for analysis. % +We now compound the multiple symptoms from one {\bc} {\fm} possibility +with the merging of Markov chains. % -This is because with the additional complication of having to change between these two modes of thinking, it becomes more difficult to +So for multiple failures we have the objective criteria complicated, and the subjective +adds another layer of complication. +% +Also with the additional complication of having to change between these two modes of thinking, it becomes more difficult to get a balance between subjective and objective perspectives. %subjective/objective become more cluttered when there are multiple possibilities