diff --git a/Thesis_Defense_Cholidis.tex b/Thesis_Defense_Cholidis.tex
index 35b58fc..17278db 100644
--- a/Thesis_Defense_Cholidis.tex
+++ b/Thesis_Defense_Cholidis.tex
@@ -327,7 +327,6 @@
 %-------------------------------------------------------------%
 
 %-------------------------------------------------------------Slide
-\setLayout{vertical}
 \begin{frame}
     \frametitle{Επιπρόσθετα Πλεονεκτήματα}
     \vspace{-3cm}
@@ -342,6 +341,7 @@
 %-------------------------------------------------------------%
 
 %-------------------------------------------------------------Slide
+\setLayout{vertical}
 \begin{frame}
     \frametitle{Υπερ-επόπτες}
     \begin{block}{Ορισμός}
@@ -364,7 +364,7 @@
 
 %-------------------------------------------------------------Slide
 \begin{frame}
-    \frametitle{Διαφορές Υπερ-επόπτη Τύπου 1 και 2}
+    \frametitle{Διαφορές υπερ-επόπτη Τύπου 1 και 2}
     \begin{columns}
         \column{0.35\textwidth}
             \begin{block}{Οι υπερ-επόπτες τύπου 1:}
@@ -630,34 +630,28 @@
 
 %-------------------------------------------------------------Slide
 \begin{frame}
-    \begin{columns}\column{\textwidth}
     \begin{figure}
         \centering
         \includegraphics[width=0.8\textwidth]{lib/figures/background/cia_confidentiality.png}
     \end{figure}
-    \end{columns}
 \end{frame}
 %-------------------------------------------------------------%
 
 %-------------------------------------------------------------Slide
 \begin{frame}
-    \begin{columns}\column{\textwidth}
     \begin{figure}
         \centering
         \includegraphics[width=0.8\textwidth]{lib/figures/background/cia_integrity.png}
     \end{figure}
-    \end{columns}
 \end{frame}
 %-------------------------------------------------------------%
 
 %-------------------------------------------------------------Slide
 \begin{frame}
-    \begin{columns}\column{\textwidth}
     \begin{figure}
         \centering
         \includegraphics[width=0.8\textwidth]{lib/figures/background/cia_availability.png}
     \end{figure}
-    \end{columns}
 \end{frame}
 %-------------------------------------------------------------%
 
@@ -922,12 +916,10 @@ Eγκατάσταση του watchtower. \\
 \section{Προτεινόμενη Λύση}
 \begin{frame}
     \frametitle{Προτεινόμενη Λύση}
-    \begin{columns}\column{\textwidth}
     \begin{figure}
         \centering
-        \includegraphics[width=0.6\textwidth]{lib/logos/secdep_logo.png}
+        \includegraphics[width=0.8\textwidth]{lib/logos/secdep_logo.png}
     \end{figure}
-    \end{columns}
 \end{frame}
 %-------------------------------------------------------------%
 
@@ -943,12 +935,12 @@ Eγκατάσταση του watchtower. \\
 \setLayout{vertical}
 \begin{frame}
     \frametitle{Μοντέλο Ανάπτυξης}
-    \begin{columns}\column{\textwidth}
+    % \begin{columns}\column{\textwidth}
     \begin{figure}
         \centering
         \includegraphics[width=0.6\textwidth]{lib/figures/development/waterfall_model.png}
     \end{figure}
-    \end{columns}
+    % \end{columns}
 \end{frame}
 %-------------------------------------------------------------%
 
@@ -1014,12 +1006,12 @@ Eγκατάσταση του watchtower. \\
 %-------------------------------------------------------------Slide
 \begin{frame}
     \frametitle{Διάγραμμα περιπτώσεων χρήσης}
-    \begin{columns}\column{\textwidth}
+    % \begin{columns}\column{\textwidth}
     \begin{figure}
         \centering
         \includegraphics[width=.75\textwidth]{lib/figures/development/secdep-use-case-diagram.jpg}
     \end{figure}
-    \end{columns}
+    % \end{columns}
 \end{frame}
 %-------------------------------------------------------------%
 
diff --git a/lib/figures/introduction/cloud_computing/saas_paas_iaas_scopes.png b/lib/figures/introduction/cloud_computing/saas_paas_iaas_scopes.png
index c1c8aa7..b30606b 100644
Binary files a/lib/figures/introduction/cloud_computing/saas_paas_iaas_scopes.png and b/lib/figures/introduction/cloud_computing/saas_paas_iaas_scopes.png differ