A friend requested this slide, it took some time to ensure all the dependencies are there (there may be some unnecessary dependencies). Since I spent some time on this and it's more than 100 lines, I thought I would put it here.

context.tex

\documentclass[xcolor={x11names, table},table,compress,10pt]{beamer}

\usepackage{varwidth, graphicx, tikz, palatino}
\usetikzlibrary{arrows,shapes.geometric,positioning}

\definecolor{oegred}{RGB}{153,0,0}
\definecolor{oegblu}{RGB}{0,0,153}

% http://tex.stackexchange.com/questions/103688/folded-paper-shape-tikz
\makeatletter
\pgfdeclareshape{document}{
\inheritsavedanchors[from=rectangle] % this is nearly a rectangle
\inheritanchorborder[from=rectangle]
\inheritanchor[from=rectangle]{center}
\inheritanchor[from=rectangle]{north}
\inheritanchor[from=rectangle]{south}
\inheritanchor[from=rectangle]{west}
\inheritanchor[from=rectangle]{east}
% ... and possibly more
\backgroundpath{% this is new
% store lower right in xa/ya and upper right in xb/yb
\southwest \pgf@xa=\pgf@x \pgf@ya=\pgf@y
\northeast \pgf@xb=\pgf@x \pgf@yb=\pgf@y
% compute corner of ‘‘flipped page’’
\pgf@xc=\pgf@xb \advance\pgf@xc by-10pt % this should be a parameter
\pgf@yc=\pgf@yb \advance\pgf@yc by-10pt
% construct main path
\pgfpathmoveto{\pgfpoint{\pgf@xa}{\pgf@ya}}
\pgfpathlineto{\pgfpoint{\pgf@xa}{\pgf@yb}}
\pgfpathlineto{\pgfpoint{\pgf@xc}{\pgf@yb}}
\pgfpathlineto{\pgfpoint{\pgf@xb}{\pgf@yc}}
\pgfpathlineto{\pgfpoint{\pgf@xb}{\pgf@ya}}
\pgfpathclose
% add little corner
\pgfpathmoveto{\pgfpoint{\pgf@xc}{\pgf@yb}}
\pgfpathlineto{\pgfpoint{\pgf@xc}{\pgf@yc}}
\pgfpathlineto{\pgfpoint{\pgf@xb}{\pgf@yc}}
\pgfpathlineto{\pgfpoint{\pgf@xc}{\pgf@yc}}
}
}
\makeatother

\tikzstyle{decision} = [diamond, draw, fill=white!20, text width=4em, text badly centered, inner sep=0pt]
\tikzstyle{block} = [rectangle, draw, fill=white!20, text centered, minimum height=2em,
   execute at begin node={\begin{varwidth}{6em}\centering},
   execute at end node={\end{varwidth}}]
\tikzstyle{line} = [draw, -latex']
% \tikzstyle{curve} = [draw, bend left, -latex']
\tikzstyle{cloud} = [draw, ellipse,fill=white!20, text badly centered, minimum height=2em,
   execute at begin node={\begin{varwidth}{6em}\centering},
   execute at end node={\end{varwidth}}]
\tikzstyle{ontology} = [draw, isosceles triangle, text centered, isosceles triangle apex angle=60,fill=white!20, minimum height=2em, shape border rotate=90]
\tikzstyle{database} = [draw, cylinder, text centered, fill=white!20, shape border rotate=90, aspect=0.2,
   execute at begin node={\begin{varwidth}{6em}\centering},
   execute at end node={\end{varwidth}}]
\tikzstyle{doc}=[draw, shape=document, inner sep=2ex] % http://tex.stackexchange.com/questions/103688/folded-paper-shape-tikz

\begin{document}
\begin{frame}{Context}
\centering
\begin{tikzpicture}[node distance = 25mm and 35mm , thick,scale=0.7, every node/.style={transform shape}, auto, on grid=true]
\node [ontology] (ontology) {ontology};
\node<5>[ontology, fill=oegred!20, yshift=-9pt, xshift=9pt] (ontology) {ontology};
\node<5>[ontology, fill=oegred!20, yshift=-6pt, xshift=6pt] (ontology) {ontology};
\node<5>[ontology, fill=oegred!20, yshift=-3pt, xshift=3pt] (ontology) {ontology};
\node<2->[ontology, fill=oegred!20] (ontology) {ontology};
\node [block, right= of ontology, draw=oegred] (rewriting) {\textbf{\textsc{rewriting}}};
\node [cloud, below= of rewriting] (query) {query};
\node<2->[cloud, below= of rewriting, fill=oegred!20] (query) {query};
\node [cloud, right= of rewriting] (rewrittenquery) {rewritten query};
\node<2->[cloud, right= of rewriting, fill=oegred!20] (rewrittenquery) {rewritten query};
\node [block, right= of rewrittenquery] (translation) {translation};
\node<3-5>[block, right= of rewrittenquery, fill=oegblu!20] (translation) {translation};
\node [cloud, right= of translation] (translatedquery) {translated query};
\node [block, below= of translatedquery] (execution) {query execution};
\node [database, left= of execution] (database) {data source};
\node<3-5>[database, left= of execution, fill=oegblu!20] (database) {data source};
\node<4>[doc, left= of database] (ebox) {EBox};
\node<5>[doc, left= of database] (mappings) {Mappings};
\node [cloud, below= of execution] (results) {results};
\node [block, left= of results] (translationres) {translation};
\node<3-5>[block, left= of results, fill=oegblu!20] (translationres) {translation};
\node [cloud, left= of translationres] (transresults) {translated results};
\node<6>[doc, densely dotted, below= of query, fill=oegblu!20] (anal) {to analyse};
\path [line] (query) -- (rewriting);
\path [line] (ontology) -- (rewriting);
\path [line] (rewriting) -- (rewrittenquery);
\path [line] (rewrittenquery) -- (translation);
\path [line] (translation) -- (translatedquery);
\path [line] (translatedquery) -- (execution);
\path [line] (execution) -- (database);
\path [line] (database) -- (execution);
\path [line] (execution) -- (results);
\path [line] (results) -- (translationres);
\path [line] (translationres) -- (transresults);
\path<4>[line, dashed] (ebox) -- (rewriting);
\path<4>[line, dashed] (database) -- (ebox);
\path<5>[line, dashed] (database) -- (mappings);
\path<5>[line, dashed] (mappings) -- (translation);
\path<5>[line, dashed] (mappings) -- (translationres);
\path<5>[line, dashed] (mappings) -- (rewriting);
\path<6>[line, densely dotted] (anal) edge[bend left] (ontology);
\path<6>[line, densely dotted] (anal) -- (query);
\path<6>[line, densely dotted] (anal) edge[bend right] (rewrittenquery);
\end{tikzpicture}


\begin{tikzpicture}[remember picture,overlay]
\node[anchor=south east, xshift=-1.2em, yshift=1.2em] at (current page.south east) {\tiny Slide modified from \href{https://gist.github.com/jmora/7489184}{Jose Mora}, with permission} ;
\end{tikzpicture}
\end{frame}
\end{document}