text: Added references

text/introduction/main.tex

@@ -1,5 +1,6 @@
 \chapter{Introduction}
 \label{ch:intro}
+\nnfootnote{This chapter was presented at the S{\~a}o Paulo School of Advanced Science on Smart Cities~\cite{katsomallos2016measuring}, as well as during the $11$th International Workshop on Information Search, Integration, and Personalization~\cite{kotzinos2016data} and at the DaQuaTa International Workshop~\cite{kotzinos2017data}.}
 
 Data privacy is becoming an increasingly important issue, both at a technical and at a societal level, and introduces various challenges ranging from the way we share and publish data sets to the way we use online and mobile services.
 Personal information, also described as \emph{microdata}, acquired increasing value and are in many cases used as the `currency'~\cite{economist2016data} to pay for access to various services, i.e.,~users are asked to exchange their personal information with the service provided.
@@ -46,7 +47,7 @@ Selecting the wrong privacy algorithm or configuring it poorly may put at risk t
 
 \begin{figure}[htp]
   \centering
-  \includegraphics[width=.5\linewidth]{introduction/data-value}
+  \includegraphics[width=.75\linewidth]{introduction/data-value}
   \caption{Value of data for decision-making over time from less than seconds to more than months~\cite{gualtieri2016perishable}.}
   \label{fig:data-value}
 \end{figure}