morning edit

This commit is contained in:
Robin Clark 2010-07-28 08:32:07 +01:00
parent aacac3a651
commit b2929352e8
4 changed files with 15 additions and 12 deletions

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@ -21,7 +21,7 @@ its components.
Once the failure modes have been determined for a sub-system, Once the failure modes have been determined for a sub-system,
we can consider this to be a `derived component' we can consider this to be a `derived component'
which can be combined with others to form which can be combined with others to form
to model higher level sub-systems, which in turn can higher level sub-systems, which in turn can
be converted to derived components. be converted to derived components.
In this way a hierarchy representing the fault behaviour In this way a hierarchy representing the fault behaviour
of a system can be built from the bottom~up. of a system can be built from the bottom~up.

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@ -6,8 +6,11 @@
The symptom abstraction process described here, is a core process in the The symptom abstraction process described here, is a core process in the
%Failure Mode Modular De-Composition %Failure Mode Modular De-Composition
FMMD modelling technique. FMMD builds a hierarchy of failure mode behaviours from the bottom up. FMMD modelling technique. FMMD builds a hierarchy of failure mode behaviours from the bottom up.
To start with collections of base components are grouped into functional~groups, which are analysed To start with collections of base components are chosen to form functional~groups, which are analysed
and then treated as components in thier own right. These higher level, or derived compoenents, w.r.t. its failure mode behaviour.
These functional groups
can then be treated as a components in their own right.
These higher level, or derived compoenents,
can be used to build derived components at higher levels of abstraction, and ultimately can be used to build derived components at higher levels of abstraction, and ultimately
are used to build an FMMD fault model hierarchy of the system modelled. are used to build an FMMD fault model hierarchy of the system modelled.
Intermediate FMMD structures may be re-used in other designs, and Intermediate FMMD structures may be re-used in other designs, and

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@ -5,7 +5,7 @@
\input{fmmd} \input{fmmd}
%\input{introduction} %\input{introduction}
\input{topbot} \input{topbot}
\input{sys_abs} %\input{sys_abs}
\input{process} \input{process}
\input{algorithm} \input{algorithm}
@ -13,7 +13,7 @@
{ {
\input{./symptom_ex_process/introduction} \input{./symptom_ex_process/introduction}
\input{./symptom_ex_process/topbot} \input{./symptom_ex_process/topbot}
\input{./symptom_ex_process/sys_abs} %\input{./symptom_ex_process/sys_abs}
\input{./symptom_ex_process/process} \input{./symptom_ex_process/process}
\input{./symptom_ex_process/algorithm} \input{./symptom_ex_process/algorithm}
} }

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@ -12,12 +12,12 @@ Static testing is also applied. This is theoretical analysis of the design of th
perspective. perspective.
Three main techniques are currently used, Three main techniques are currently used,
Statistical failure models, FMEA (Failure mode Effects Analysis) and FTA (Fault Tree Analysis). Statistical failure models, FMEA (Failure mode Effects Analysis) and FTA (Fault Tree Analysis).
The FMMD technique is aimed primarily as design verification for The FMMD technique is a static modelling methodology, aimed primarily as design verification for
safety critical systems. safety critical systems.
However, FMMD also provides the mathematical frame work However, FMMD also provides the mathematical frame work
to assist in the production of these three results of static analysis. to assist in the production of the three traditional methods of static analysis.
From the model created by the FMMD technique, the three above failure mode From the model created by the FMMD technique, statistical, FTA and FMEA models
descriptions can be derived. can be derived.
FMMD can model electrical, mechanical and software using a common notation, FMMD can model electrical, mechanical and software using a common notation,
and can thus model an entire electro mechanical software controlled system. and can thus model an entire electro mechanical software controlled system.
@ -90,7 +90,7 @@ for each `component'.
If we look at the sound system example, If we look at the sound system example,
the CD~player could fail in several distinct ways, the CD~player could fail in several distinct ways,
and this couldbe due to a large number of and this could be due to a large number of
component failure modes. component failure modes.
%no matter what has happened to it or has gone wrong inside it. %no matter what has happened to it or has gone wrong inside it.
@ -115,8 +115,8 @@ to perform a specific function.
When we have analysed the fault behaviour of a functional group, we can treat it as a `black box'. When we have analysed the fault behaviour of a functional group, we can treat it as a `black box'.
The fault behaviour will consist of a set of `symptoms' caused by combinations The fault behaviour will consist of a set of `symptoms' caused by combinations
of the component failure modes. of its component failure modes.
We can make a new `component' derived from the functional~group. We can thus make a new `component' derived from the functional~group.
The symptoms are the failure modes of this new `derived component'. The symptoms are the failure modes of this new `derived component'.
%We can now call our functional~group a sub-system or a derived~component. %We can now call our functional~group a sub-system or a derived~component.