\ifthenelse {\boolean{paper}} { \abstract{ This paper proposes a methodology for creating failure mode models of safety critical systems, which have a common and integrateable notation for mechanical, electronic and software domains. The proposed methodology is bottom-up and modular. } } {} \section{Introduction} \section{Some requirements for a failure mode methodolgy} \begin{itemize} \item All component failure modes must be considered in the model. \item It should be easy to integrate mechanical, electronic and software models. \item It should be re-usable, in that commonly used modules can be re-used in other designs/projects. \item It should have a formal babsis, that is to say it should be able to produce mathematical proofs for its results. \item It should be capable of producing reliability and danger evaluation statistics. \item It should be easy to use. \end{itemize} OK need to describe the need for it AND then how we can solve all there problems AND then a rough outline of what is needed AND then a general description of symptom extraction AND the hierarchy... Probab about 3 pages