diff --git a/symptom_ex_process/symptom_ex_process.tex b/symptom_ex_process/symptom_ex_process.tex
index f06521e..3386126 100644
--- a/symptom_ex_process/symptom_ex_process.tex
+++ b/symptom_ex_process/symptom_ex_process.tex
@@ -7,8 +7,11 @@ In failure mode analysis, it is essential to
 know the failure modes of the sub-systems and components used.
 This paper outlines a technique for determining the failure modes of a sub-system given 
 its components.
-
-This chapter describes a process for taking a functional group of components, applying FMEA analysis and then determining how that functional group can fail.
+%
+This paper describes a process for taking a functional~group of components,
+applying FMEA analysis on all the component failure modes possible in that functional~group,
+and then determining how that functional group can fail.
+%
 With this information, we can treat the functional group
 as a component in its own right.
 This new component is a derived component.
@@ -34,16 +37,57 @@ of FTA\cite{nasafta} (Fault Tree Analysis) and mimimal cuts sets\cite{nucfta} ar
 Also statistical reliability/probability of failure~on~demand\cite{en61508} and MTTF (Mean Time to Failure) calculations can be produced 
 automatically, where component failure mode statistics are available\cite{mil1991}.
 %
-This paper focuses on the process of building the blocks, that are key to creating an FMMD hierarchy.
-
+%
+This paper focuses on the process of building the blocks, the symptom extraction or abstraction process, that is key to creating an FMMD hierarchy.
 \end{abstract}
 }
-{}
+{
+\section{Introduction}
+
+In failure mode analysis, it is essential to
+know the failure modes of the sub-systems and components used.
+This paper outlines a technique for determining the failure modes of a sub-system given 
+its components.
+%
+This chapter describes a process for taking a functional group of components,
+applying FMEA analysis on all the component failure modes possible in that functional~group,
+and then determining how that functional group can fail.
+%
+%
+With this information, we can treat the functional group
+as a component in its own right.
+This new component is a derived component.
+For a top down technique this would correspond to a low~level sub-system.
+%The technique uses a graphical notation, based on Euler\cite{eulerviz} and Constraint diagrams\cite{constraint} to model failure modes and failure mode common symptom collection.  The technique is designed for making building blocks for a hierarchical fault model.
+%
+Once the failure modes have been determined for a sub-system/derived~component,
+this derived component can be combined with others to form functional groups
+to model 
+higher level sub-systems/derived~components. 
+%
+In this way a hierarchy to represent the fault behaviour
+of a system can be built from the bottom~up. This process can continue
+until there is a complete hierarchy representing the failure mode
+behaviour of the entire system under analysis.
+%FMMD hierarchy
+Using the FMMD technique the hierarchy is built from the bottom up to ensure complete failure mode coverage.
+Because the process is bottom-up, syntax checking and tracking can ensure that
+no component failure mode can be overlooked.
+Once a hierarchy is in place it can be converted into a fault data model.
+%
+From the fault data model, automatic generation
+of FTA\cite{nasafta} (Fault Tree Analysis) and mimimal cuts sets\cite{nucfta} are possible. 
+Also statistical reliability/probability of failure~on~demand\cite{en61508} and MTTF (Mean Time to Failure) calculations can be produced 
+automatically, where component failure mode statistics are available\cite{mil1991}.
+%
+This chapter focuses on the process of building the blocks, the symptom extraction or abstraction process, that is key to creating an FMMD hierarchy.
+
+
+}
 
 
 %\clearpage
 
-\section{Introduction}
 
 \subsection{Top Down or natural trouble shooting}
 It is interesting here to look at the `natural' trouble shooting process.