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\chapter*{Colophon}

In short ``Thanks every body''!
%
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\\
%
%Completing my PhD %degree 
%is the most intellectually challenging                   %% FUCK OFF ZERNIKE POLYNOMIALS WERE MORE DIFFICULT --- and actually useful unlike set theory
%activity of my first 52 years of my life!                %% SET THEORY IS A LOAD OF BOLLOCKS
%
%The best and worst moments of this journey 
%have been shared with many people. 
%
It has been a great privilege to spend several years 
visiting the Mathematics and Engineering departments of 
the University of Brighton, pushing me forward in clarity of self-expression,
precision through mathematics, critical assessment and carefully crafted English:
its members will always remain dear to me. %, and I am sure, a strong influence
%on work I produce after this.
%
%%%% IS THIS BIT A BIT MAD???? YES! 27AUG2013
% % % Like an army recruits training Sergeant Major I found them 
% % % hard task masters at first, and then, as with realising the rationale behind training and
% % % {\em even} parade drill, respected and grew to like them. well one of them anyway, the one who actually helped. the one with the motorbike.
% % % %
%
My first debt of gratitude must go to my supervisors, 
Dr. A. Fish,
Dr. C Garret and        %% TOP BLOKE
%Dr. C Garret,          %% TOP BLOKE
Professor J. Howse. %% LAT HUND
%Dr. A. Fish.          %% JAVALA LAT HUND
%
They patiently provided the guidance, 
encouragement and advice necessary for me to proceed through the 
research, consolidation and write-up phases of the PhD program,
to prepare and present three papers to conferences~\cite{syssafe2011,syssafe2012,Clark_fastzone}  
and to complete and submit this thesis. 
\\
\\
%
%
I owe a debt of thanks to Dr J. flower, my MSc project supervisor, 
who explained that the chapter in my project documentation postulating a modular form of
FMEA---which had %obvious 
potential for making the process %FMEA
more efficient---was a concept worthy of being developed for a PhD and assisting  me
to present the chapter as %submit this as 
a conference paper~\cite{Clark200519}.
%
Further I thank her for encouraging me to apply for the PhD. %% PITY SHE DID NOT STAY ON AS MY PHD SUPERVISOR
%
I also wish to thank Alan Jones of  Brighton College of Technology
for taking a chance on someone with no `A' levels and letting him
start an HND in software Engineering in 1986. That more than anything
changed my life and gave me fantasic opportunities.
\\
\\
%
I am deeply thankful to the directors of {\etc} not only for
funding this course, but providing training and work experience in the
field of safety critical engineering and giving me Friday
afternoons to pursue my studies.
%
At Energy~Technology~Control, the following people gave encouragement, and
validated the concepts for the `modular~FMEA' that I was developing, 
Martin~Thirsk, 
Colin~Talmay and
Darren~Legge. % and 
%% Hazel~Anderson. Varfor satter min bok i 60oC du eller skitstovlen... 
%
These Engineers, whose whole careers
have been focused on the safety critical electronic/computing area,
gave valuable time to look at and comment on my FMMD proposals.
%
Their comments gave me confidence that the methodology I was developing had
%was not only an academic exercise but had 
potential practical 
applications and benefits.
%
The environment and context of the work at {\etc}
was very useful for clarifying concepts relating to FMEA and 
safety; at least once a week there is  a new practical case study arising
and being discussed, be it, say, the observability of the effect of failures in an 
traditional amplifier configuration,
or how a particular sensor could fail. 
%
The field of industrial burner control, is highly regulated and
is rich with practical examples of safety measures built into
hybrid digital/electronic systems.
%
This has given me many opportunities to %  has been % be
apply the new methodology against `real~world' problems.
%
%and thus its 
%theoretical aspects have been  often
%sounded out  against `real~world' problems.
%
These real~world failure scenarios and their proposed solutions, were often detailed in  
requirements and design documentation, submitted in support of 
safety accreditation. 
%
I was glad to be tasked to produce many of these documents.
%
Again I thank {\etc}, for giving me
these parallel tasks, which aided my studies.
\\
\\
%
%
I wish to thank my parents, Jennifer and Richard Clark.
% MY MUM for proof reading alot!
I hope that this work makes you proud.
%
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\clearpage

 \chapter*{Declaration}

I declare that the research contained in this thesis, unless otherwise formally indicated within the 
text, is the original work of the author.  The thesis has not been previously submitted to this or any 
other university for a degree, and does not incorporate any material already submitted for a 
degree.
\\
\\
\\
\\
Signed
\\
\\
\\
Dated
\clearpage


\section*{Abstract}

\subsection*{Failure Mode Modular De-Composition}

%
% This should be a three hundred word summary of the work and findings
% Supervisors did not warn me this was required.
% I found out by reading the OU ``how to get a PhD'' book in the bath, and then wading through the Brighton University
% regulations where it is stated on page 14 of a 30+ page document filled with mostly n/a regulations to me.
%
%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% BEGINING --- Introduce the field
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
The certification process of safety critical products for European and other international 
standards typically demand environmental stress, endurance and electro magnetic compatibility testing. 
%
Theoretical, or `static~testing' also a requirement. 
%
Failure Mode Effects Analysis (FMEA) is a tool used for static testing.
FMEA is a bottom-up technique that aims to assess the effects 
of all component failure modes in a system.
%
Its use is traditionally limited to hardware systems. % only. 
%
With the growing complexity of modern electronics traditional FMEA
is suffering from state explosion and re-use of analysis problems.
%
Also with the now ubiquitous use of micro-controllers in smart~instruments and control systems, 
software is increasingly being seen as a `missing~factor' for FMEA. % analysis.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Middle work and findings
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
This thesis presents a new modular variant of FMEA, Failure Mode Modular Decomposition (FMMD).
%
FMMD has been designed to integrate mechanical/electronic and software 
failure models, by treating them all as components  in terms of their failure modes. 
%
For instance, software functions, 
electronic and mechanical components
can all be assigned sets of failure modes.
%
FMMD builds failure mode models from the bottom-up by incrementally analysing
{\fgs} of components, using the results of analysis to create higher level {\dcs},
which in turn can be used to build {\fgs}.
%
In this way a hierarchical failure mode model 
is built. 
%
Software functions are treated as components by FMMD and can thus be incorporated seamlessly into
the failure mode hierarchical model.
%
A selection of examples, electronic circuits and hardware/software hybrids are analysed using 
this new methodology.
%
The results of these analyses are then discussed from the perspective of safety critical application.
%
Performance in terms of test efficiency is greatly improved by FMMD and 
the examples analysed and theoretical models are used to demonstrate this.
%

%Because FMMD is modular and hierarchical, and deals with all its objects in 
%terms of their failure mode behaviour, it is ideally suited to creating integrated software and hardware models.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% End what has been achieved ---- all in 300ish word OK here we go.
%Conclusions are presented listing the 
%and FMMD is compared with traditional HFMEA and SFMEA.
This thesis presents a methodology that solves the state explosion problems of FMEA;
provides integrated hardware and software failure mode models;
facilitates multiple failure mode analysis;
encourages re-use of analysis work
and can be used to produce traditional format FMEA reports.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 
% The certification process of safety critical products for European and other international 
% standards often demand environmental stress, endurance and Electro Magnetic Compatibility (EMC) testing. 
% Theoretical, or `static testing',is often also required. Failure Mode effects Analysis (FMEA) is a tool used for static testing. 
% Its use is traditionally applied to hardware (electrical and mechanical) systems. 
% With the increasing use of micro-controllers in smart~instruments and control systems, 
% software is increasingly being seen as the `missing factor' in FMEA analysis. 
% This paper presents a new modular variant of FMEA, Failure Mode Modular Decomposition (FMMD).
% Because FMMD is modular and hierarchical, and deals with all its objects in 
% % terms of their failure mode behaviour, it is ideally suited to creating integrated software and hardware models.
% FMEA is a bottom-up technique that aims to assess the effects 
% of all component failure modes on a system. It is used both as a design tool (to determine weaknesses), 
% and is a requirement of certification of safety critical products. FMEA has been successfully applied to
% mechanical, electrical and hybrid electro-mechanical systems. Work on software FMEA (SFMEA) is beginning, 
% but at present no technique for SFMEA that integrates hardware and software models exists. 
% Software in current embedded systems practise sits on top of most modern safety critical control systems 
% [and inside many  data collection/actuator modules (smart~instruments)], and defines their most important
% system wide behaviour, interfaces and communications. Currently standards  that demand FMEA for hardware 
% (e.g. EN298, EN61508), do not specify it for software, but instead specify, computer architecture, good software practise,
% review processes and language feature constraints. Where FMEA traces component failure modes to resultant system failures,
% software has been left in a non-analytical limbo of best practises and constraints. Where SFMEA has been applied---for some 
% automotive and highly safety critical systems---it has always been performed  separately from  hardware FMEA (HFMEA). 
% %
% At present the hardware/software interface is a source for confusion and misunderstanding, and in many organisations, 
% the actual design teams for software and hardware work in separate departments. Subtle errors of electronic systems for instance, 
% may not be picked up by software specialists, and vice versa. It would be  desirable to have a methodology that provides seamless 
% software and hardware integration in its failure modelling. FMMD has been designed to integrate mechanical/electronic and software 
% failure models, by treating all modular components  in terms of their failure modes. For instance, a software function, 
% or an electronic or a mechanical component can be assigned a known set of failure modes.
% This paper presents an overview of the FMMD methodology and then an FMMD analysis of a simple software/hardware hybrid sub-system. 
% 
% 
% The example system chosen is a 4->20mA input circuit consisting of a resistive element, multiplexer (MUX), 
% Analogue to Digital Converter (ADC) and two software functions. The purpose of this system is to convert an 
% electrical current signal into a value for use in software. FMMD is applied to the hardware (resistive element, MUX and ADC) 
% and  to the software components (two `C' functions), producing one integrated failure mode model.  
% The 4->20mA input circuitry used in the example and its related software, are accepted practise and in 
% common use, and therefore its failure mode behaviour is well known and understood. For this reason it is a
% good example to use for comparing the  results from FMMD analysis with known failure mode behaviour 
% from the field/direct experience of engineers. The  failure model is then discussed and compared with 
% heuristic knowledge of 4->20mA inputs, circuitry and software.
% Conclusions are then presented listing the benefits and draw-backs of analysing the
% hardware/software hybrid system using FMMD, and FMMD is compared with traditional HFMEA and SFMEA.


