diff --git a/mybib.bib b/mybib.bib index 6498d39..e6b1090 100644 --- a/mybib.bib +++ b/mybib.bib @@ -113,6 +113,16 @@ ISSN={Doi:10.1145/2330667.2330683},} YEAR = "2011" } + +@ARTICLE{fftoriginal, + author={James W. Cooley and John W. Tukey}, + journal={Mathematics of Computation}, + year={1965}, + volume={19}, + pages={297-301}, + publisher={American Mathematical Society} +} + @article{Lutz:1997:RAU:590564.590572, author = {Lutz, Robyn R. and Woodhouse, Robert M.}, title = {Requirements analysis using forward and backward search}, diff --git a/submission_thesis/CH1_introduction/copy.tex b/submission_thesis/CH1_introduction/copy.tex index 86186e7..2302771 100644 --- a/submission_thesis/CH1_introduction/copy.tex +++ b/submission_thesis/CH1_introduction/copy.tex @@ -23,7 +23,7 @@ The ability to assess the safety of man made equipment has been a concern since the dawn of the industrial age~\cite{usefulinfoengineers,steamboilers}. The philosophy behind safety measure has progressed with time, and by World War Two we begin to see concepts such as `no single component failure should cause -a dangerous system failure'~\cite{echoesofwar}[Ch.13] emerging. +a dangerous system failure'~\cite{boffin} emerging~\cite{echoesofwar}[Ch.13]. % Concepts such as these allow us to apply objective criteria to safety assessment. We can extend the `no~single~failure' concept @@ -32,8 +32,9 @@ to double or even multiple failures being unacceptable as the cause of dangerous The concept of a double failure causing a dangerous condition being forbidden can be found in the legally binding European standard EN298\footnote{EN298:2003 became a legal requirement for all new forced draft industrial burner controllers in 2006 within -the European Union.} which became -a legal requirement in 2006~\cite{en298}. +the European Union.} which +came into force +in 2006~\cite{en298}. % More sophisticated statistically based standards, i.e EN61508~\cite{en61508} and variants thereof, are based on statistical thresholds for the frequency of dangerous failures. @@ -55,12 +56,12 @@ the higher SIL rating we can demand for it. A band-saw with one operative may require a SIL rating of 1, a nuclear power-station, with far greater consequences on dangerous failure may require a SIL rating of 4. -SIL ratings give us another objective yardstick to measure system safety. +SIL ratings give us another objective yardstick for the measurement of system safety. %governing failure conditions and determining risk levels associated with systems. All of these risk assessment techniques are based on variations of %on the theme of Failure Mode Effect Analysis (FMEA), which has its roots in the 1940's mass production industry -and was designed to save large companies money by prioritising most financially +and was designed to save large companies money by prioritising the most financially draining problems in a product. % first. % The FMEA of the 1940's has been refined and extended into four main variants. @@ -94,7 +95,7 @@ MSc and my project was to create an Euler/Spider~Diagram~\cite{howse:spider} edi This editor allowed the user to draw Euler/Spider diagrams, and could then represent these as abstract---i.e. mathematical---definitions. The primary motive for writing the Spider diagram editor was to provide an alternative -to to formal languages for software specification. +to formal languages for software specification. Because of my exposure to FMEA, I started thinking of ways to apply formal languages and spider diagrams to failure mode analysis. \paragraph{European Safety Requirements increase in scope and complexity.} @@ -127,13 +128,13 @@ analysis of identical circuitry was performed many times. % % -\paragraph{Modularising/De-Composing FMEA: Initial concepts.} % and augmenting this with concepts from Euler/Spider Diagrams.} +\subsection{Modularising/De-Composing FMEA: Initial concepts.} % and augmenting this with concepts from Euler/Spider Diagrams.} In the field of digital signal processing there is an algorithm that revolutionised -access to frequency analysis of digital samples called the Fast Fourier transform (FFT)~\cite{fpodsadsp}[Ch.8]. +access to frequency analysis of digital samples called the Fast Fourier transform (FFT)~\cite{fftoriginal}. This took the discrete Fourier transform (DFT), and applied de-composition to its -mesh of (often repeated) complex number calculations. -By doing this it broke the problem down from having an exponential -order to a polynomial~\cite{ctw}[pp.401-3]. +mesh of (often repeated) complex number calculations~\cite{fpodsadsp}[Ch.8]. +By doing this it broke the computing order of complexity problem down from having a polynomial %n exponential +order to logarithmic order~\cite{ctw}[pp.401-3]. I wondered if this thinking could be applied to the state explosion problems encountered in FMEA. % %Following the concept of de-composing a problem, and thus simplifying the state explosion---using the thinking behind @@ -142,7 +143,7 @@ I wondered if this thinking could be applied to the state explosion problems enc My reasoning was that were we to analyse the problem in small modules, from the bottom-up following the FFT example, we could apply checking for all double failure scenarios. % -Once these first modules were analysed---we now call them {\fgs}--we could determine the symptoms of failure for them. +Once these first modules were analysed---we now call them {\fgs}---we could determine the symptoms of failure for them. Using the symptoms of failure, we could now treat these modules as components in their own right---or {\dcs}---and use them to build higher level {\fgs}. Higher and higher levels of {\fgs} could be built until we had a hierarchy representing a failure mode model for the system. @@ -157,7 +158,7 @@ every double simultaneous failure of all components in a system. % This means, as a fortunate by-product, that many multiple as well as double failures would be analysed, but because failure modes are traceable from the base components to the top level---or system---failure modes -and these can be held in a traversable data structure. +these relationships can be held in a traversable data structure. % If held in a traversable data structure we can apply automated methods to search all the cardinalities of multiple failure modes within the model. @@ -183,6 +184,7 @@ meant that the analyst was forced to associate one component failure mode with o % These concepts were presented at the ``Euler~2004''~\cite{Clark200519} conference held at Brighton University. This defined the concepts for modularising FMEA using the formal visual notations from Spider diagrams. +This lead to work on rapidly calculating available zones in Euler diagrams~\cite{Clark_fastzone}. % The spider diagram notation was useful in defining the concepts and initial ideas, but a more traditional `spreadsheet' format has been used @@ -194,7 +196,7 @@ variant of FMEA that this thesis proposes and defends. % % -\subsection{Objectives of the thesis.} +\section{Objectives of the thesis.} The primary objective of the work performed for this thesis is to present a new modularised variant of FMEA which solves the problems of: \begin{itemize} @@ -203,15 +205,16 @@ FMEA which solves the problems of: \item Re-usability of pre-analysed modules, \item Inclusion of software in failure mode modelling. \end{itemize} -To support this worked examples using the new methodology were created and the work published and presented to +To support this, worked examples using the new methodology were created and the work published and presented to IET safety conferences. % in 2011~\cite{syssafe2011} and 2012~\cite{syssafe2012}. -The development of this new methodology +The development of FMMD, starting with a critique of FMEA and a wish-list for a better methodology, was presented to the IET System safety conference in 2011,~\cite{syssafe2011}. FMEA, currently cannot integrate software into its failure mode models~\cite{sfmea,modelsfmea,embedsfmea,sfmeainterface}. -A modular variant of FMEA can use the existing structure of functional software, in conjunction -with contract programming, to model software~\cite{syssafe2012}. +FMMD can use the existing structure of functional software, in conjunction +with contract programming, to model software and this concept was presented to the IET System safety conference in 2012~\cite{syssafe2012}. +\paragraph{Overview---quick guide to contents of the thesis.} Chapter~\ref{sec:chap2} examines the current state of FMEA based methodologies, Chapter~\ref{sec:chap3} examines the benefits and drawbacks of these methodologies and proposes a detailed wish list for an ideal FMEA technique. diff --git a/vmgbibliography.bib b/vmgbibliography.bib index 9067b84..962a50b 100644 --- a/vmgbibliography.bib +++ b/vmgbibliography.bib @@ -11,11 +11,12 @@ year = {2007} } -@MISC{Clark_fastzone, +% FZD fzd +@ARTICLE{Clark_fastzone, author = {Robin Clark}, - title = {Fast Zone Discrimination}, - year = {2007}, - booktitle = {Submitted to Visual Languages and Computing 2007}, + title = {Fast Zone Discrimination, an algorithm for quickly determining available zones in Euler diagrams using the java area and shape classes}, + year = {2007}, + journal = {Visual Languages and Computing 2007, Idaho, USA}, }