\documentclass{llncs}
\usepackage[american]{babel}
\usepackage[T1]{fontenc}
\usepackage{times}
\usepackage{graphicx}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}

\title{Improving plagiarism detection}
%%% Please do not remove the subtitle.
\subtitle{Notebook for PAN at CLEF 2013}

\author{\v{S}imon Suchomel \and Jan Kasprzak \and Michal Brandejs}
\institute{Faculty of Informatics, Masaryk University \\
{\tt\{suchomel,kas,brandejs\}@fi.muni.cz}}

\maketitle

\begin{abstract}
This paper describes approaches used for the Plagiarism Detection task in PAN 2013 international competition
on uncovering plagiarism, authorship, and social software misuse.  
We present modified three-way search methodology for Source Retrieval subtask and analyse snippet similarity performance.
Next, we show changes in selected feature for text alignement which led to plagdet score improvement.
The results of source retrieval show, that presented approach is adaptable in real-world plagiarism situations.
Improved results for text alignment achieved in the competition overall third place.
\end{abstract}


\section{Introduction}
In PAN 2013 competition on plagiarism detection we participated in both the Source Retrieval
and the Text Alignment subtask. In both tasks we adapted methodology used in PAN 2012.
Section~\ref{source_retr} describes querying approach for source retrieval, where we used three different 
types of queries. We present a new type of query based on text paragraphs.
The query execution were controled by its type and by preliminary similarities
discovered during the searches. 
In section~\ref{text_alignment} we present modified common text feature fot text alignment.
We also compare performance of both the previous and the modified algorithms. 


\input{simon-source_retrieval}
\input{yenya-text_alignment}


\section{Conclusions}

Unfortunately the ChatNoir search engine does not support phrasal search, therefore it
is possible that evaluated results may be quite distorted in this manner.

\bibliographystyle{splncs03}
\begin{raggedright}
\bibliography{pan13-notebook}
\end{raggedright}

\end{document}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

