Changeset 67 for papers


Ignore:
Timestamp:
Mar 14, 2012, 4:27:45 PM (13 years ago)
Author:
cecile
Message:

Refinement text filter added

Location:
papers/FDL2012
Files:
2 edited

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  • papers/FDL2012/abstraction_refinement.tex

    r65 r67  
    1515$\widehat{M_{i+1}}$.
    1616\end{enumerate}
     17\label{def:goodrefinement}
    1718\end{definition}
    1819
  • papers/FDL2012/ordering_filter_properties.tex

    r65 r67  
    100100%\bigskip
    101101
    102 \emph{\underline{Example:}}  \\
    103 
    104 For example, if a global property $\phi$ consists of 3 variables: $ p, q, r $ where:
    105 \begin{itemize}
    106 \item{$p$ is dependent of $a$ and $b$}
    107 \item{$b$ is dependent of $c$}
    108 \item{$q$ is dependent of $x$}
    109 \item{$r$ is independent}
    110 \end{itemize}
    111 
    112 Example with unit weight= 50.
    113 The primary variables: $p$, $q$ and $r$ are weighted $100x10=1000$ each. \\
    114 The secondary level variables : $a$, $b$ and $x$ are weighted $50x2=100$ each. \\
    115 The tertiary level variable $c$ is weighted $50$. \\
    116 The weight of a non-related variable is $0$.
    117 
    118 So each verified properties available pertinency will be evaluated by adding the weights of all the variables in it. It is definitely not an exact pertinency calculation of properties but provides a good indicator of their possible impact on the global property.
    119 
    120 \bigskip
    121 \begin{figure}[h!]
    122    \centering
    123 %   \includegraphics[width=1.2\textwidth]{Dependency_graph_weight_PNG}
    124 %     \hspace*{-15mm}
    125      \includegraphics{Dependency_graph_weight_PNG}
    126    \caption{\label{DepGraphWeight} Example of weighting}
    127 \end{figure}
     102%\emph{\underline{Example:}}  \\
     103%
     104%For example, if a global property $\phi$ consists of 3 variables: $ p, q, r $ where:
     105%\begin{itemize}
     106%\item{$p$ is dependent of $a$ and $b$}
     107%\item{$b$ is dependent of $c$}
     108%\item{$q$ is dependent of $x$}
     109%\item{$r$ is independent}
     110%\end{itemize}
     111%
     112%Example with unit weight= 50.
     113%The primary variables: $p$, $q$ and $r$ are weighted $100*10=1000$ each. \\
     114%The secondary level variables : $a$, $b$ and $x$ are weighted $50x2=100$ each. \\
     115%The tertiary level variable $c$ is weighted $50$. \\
     116%The weight of a non-related variable is $0$.
     117%
     118%
     119%\bigskip
     120%\begin{figure}[h!]
     121%   \centering
     122%%   \includegraphics[width=1.2\textwidth]{Dependency_graph_weight_PNG}
     123%%     \hspace*{-15mm}
     124%     \includegraphics{Dependency_graph_weight_PNG}
     125%   \caption{\label{DepGraphWeight} Example of weighting}
     126%\end{figure}
    128127
    129128%Dans la figure~\ref{étiquette} page~\pageref{étiquette},  
     
    131130
    132131
    133 After this pre-processing phase, we will have a list of properties $L_\phi  $ ordered according to their pertinency in comparison to the global property.
    134 
    135 
    136 
     132Each verified properties available pertinency will be evaluated by adding the weights of all the variables in it.
     133It is definitely not an exact pertinency calculation of properties but provides a good indicator
     134of their possible impact on the global property.
     135After this pre-processing phase, we will have a list of properties $L_\phi$
     136ordered according to their pertinency in comparison to the global property.
    137137
    138138
     
    140140
    141141\subsection{Filtering properties}
    142 \TODO{Explaining w.r. to good refinement}
     142The refinement step consists of adding new AKS of properties selected according to
     143their pertinency. This refinement respects the points 1 and 2 of definition
     144\ref{def:goodrefinement}. The first item comes form AKS definition.
     145Adding a new AKS in the abstraction leads to an abstraction where more behaviors
     146are characterized. Hence there is more constrains behavior and more concretize
     147states.
     148
     149\Remark{Cécile}{Mettre definition, property and proof ?????}
     150
     151Unforutnatly, this refinement does not ensure that the spurious counter-example
     152is evicted.
     153As we would like to ensure the elimination of the counterexample previously found,
     154we filter out properties that don't have an impact on the counterexample $\sigma_i$ thus won't eliminate it.
     155In order to reach this obective, a AKS of the counterexample $\sigma_i$, $K(\sigma_i)$
     156is generated. $K(\sigma_i)$ is a succession of states corresponding to the counterexample path which dissatisfies
     157the global property $\Phi$. It is an abstract kripke structure since not all
     158variables are concrete.
     159Each properties
     160All the properties available are then model-checked on $K(\sigma_i)$. If the
     161property holds then the property will not discriminate the counter-example.
     162Hence this property is not a good candidate for refinement.
     163Therefore all properties that are satisfied won't be chosen to be integrated in the next step of refinement. At this stage, we already have a list of potential properties that will definitely eliminate the current counterexample $\sigma_i$ and might converge the abstract model towards a model sufficient to verify the global property $\phi$.
     164
     165
     166\TODO{Revoir la definition et Proof}
     167
    143168The refinement process from $\widehat{M}_i$ to $\widehat{M}_{i+1}$ can be seperated into 2 steps:
    144169
     
    216241
    217242
    218 Therefore all properties that are satisfied won't be chosen to be integrated in the next step of refinement. At this stage, we already have a list of potential properties that will definitely eliminate the current counterexample $\sigma_i$ and might converge the abstract model towards a model sufficient to verify the global property $\phi$.
    219 
    220243}
    221244%\bigskip
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