\documentclass{scrartcl}
\setlength\paperwidth{20.999cm}
\setlength\paperheight{29.699cm}
\setlength\voffset{-1in}
\setlength\hoffset{-1in}
\setlength\topmargin{1.499cm}
\setlength\headheight{12pt}
\setlength\headsep{.7cm}
\setlength\footskip{1.131cm}
\setlength\textheight{25cm}
\setlength\oddsidemargin{2.499cm}
\setlength\textwidth{15.999cm}
\setlength\parindent{0cm}
\setlength\parskip{0.3em}

\usepackage{amsmath}
\usepackage{listings}
\usepackage{xcolor}
\usepackage{fancyvrb}
\usepackage{newverbs}
\usepackage{fancyhdr}
\usepackage{extramarks}
\usepackage{graphicx}
\usepackage{mathtools}
\usepackage{multicol}
\usepackage{hyperref}
\usepackage{booktabs}
\usepackage{float}
\usepackage{subcaption}

\pagestyle{fancy}
\lhead{Aksakal, Maggioni, Riggio - Bug Triaging}
\DeclarePairedDelimiter\ceil{\lceil}{\rceil}
\DeclarePairedDelimiter\floor{\lfloor}{\rfloor}

\newcommand\vartextvisiblespace[1][.6em]{%
    \makebox[\#1]{%
        \kern.07em
        \vrule height.4ex
        \hrulefill
        \vrule height.4ex
        \kern.07em
    }%
}

\begin{document}
    \thispagestyle{plain}

    \begin{center}
        \hrule

        \vspace{.4cm}
        {\textbf {\Huge Bug Triaging}} \\
        \vspace{.2cm}
        {\textbf Software Analytics}
        \vspace{.2cm}
    \end{center}
    {\textbf Baris Aksakal } (baris.aksakal@usi.ch) \hspace{\fill}  \\
    {\textbf Claudio Maggioni } (claudio.maggioni@usi.ch) \hspace{\fill}  \\
    {\textbf Edoardo Riggio } (edoardo.riggio@usi.ch) \hspace{\fill} \today \\
    \hrule
    \vspace{.2cm}

    \input{./sections/introduction}
    \input{./sections/scraping}
    \input{./sections/cleaning}
    \input{./sections/statistics}
    \input{./sections/prototype_model}
    \input{./sections/model}
    \input{./sections/references}

\end{document}