\chapter{Main contribution}
\section{Methods}
\subsection{Content based modelling}
Classifier creates a model for each user based on the acoustic features of the tracks that user has liked.
\subsection{Collaborative filtering}
At this stage, similarities between users is calculated to form a neighbourhood and predict user rating based on combination of the ratings of selected users in the neighbourhood.
\section{Algorithms}
\subsection{Deep Belief Networks}
Deep belief network is a probabilistic model that has one observed layer and several hidden layers.
\subsubsection{Convolutional Deep Belief Network (CDBN)}
