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+\usepackage{fontspec}\r
+\usepackage{xunicode}\r
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+\renewcommand{\SubSection}[2][?]{\r
+ \vspace{0.5\secskip}\r
+ \refstepcounter{subsection}\r
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+}\r
+\r
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\r
%%% Begin of Document\r
\r
The whole process is depicted at picture~\ref{fig:process}. The source retrieval task is divided into\r
2 subtasks: Quering and Selecting, during which the software utilizes given search engine. The retrieved\r
sources must be examined in detail in order to highlight as many plagiarism cases as possible. This process is depicted\r
-as Text Alignment.\r
-\r
+as Text Alignment. Results of this process are called {\em detections}, i.e.~passages of {\em source document} and {\em suspicious document}, which are similar enough to each other, and can serve as a basis for further manual examination for possible plagiarism.\r
%\r
\vfill\r
\columnbreak\r
\begin{minipage}{0.55\linewidth}\r
\subsection{Intrinsic Plagiarism Based Queries}\r
\begin{ytemize}\r
-\item Averaged Word Frequency Class based chunking~\cite{AWFC};\r
+\item Averaged Word Frequency Class based chunking~\cite{awfc};\r
\item Random sentence selection from the chunk;\r
\item Non-deterministic;\r
\item Positional;\r
\section{Selecting}\r
Document snippets were used for deciding whether to download the document for the text alignment.\r
We used 2-tuples measurement, which indicates how many neighbouring word pairs coexist in the snippet and in the suspicious document.\r
-Performance of this measure is depicted at picture~\ref{fig:snippet_graph}.\r
+Performance of this measure is depicted at Figure~\ref{fig:snippet_graph}.\r
Having this measure, a threshold for download decision needs to be set in order to maximize all discovered similarities\r
and minimize total downloads.\r
A profitable threshold is such that matches with the largest distance between those two curves.\r
\r
\section{Text Alignment}\r
\r
+The system uses the same basic principles as in \cite{suchomel_kas_12}:\r
+\r
+\begin{ytemize}\r
+\item{\cemph{common features} between source and suspicious documents}\r
+\begin{ytemize}\r
+\item{word 5-grams}\r
+\item{stop-word 8-grams \cite{stamatatos2011plagiarism}}\r
+\end{ytemize}\r
+\item{\cemph{valid intervals} of characters covered by common features\r
+ ``densely enough''}\r
+\item{\cemph{postprocessing}---remove overlapping detections,\r
+ join neighbouring detections}\r
+\end{ytemize}\r
+\r
+\subsection{Alternative Features}\r
+\r
+\begin{ytemize}\r
+\item{\cemph{contextual n-grams} \cite{torrejondetailed}}\r
+\begin{ytemize}\r
+\item{\cemph{The quick} brown \cemph{fox jumped} over the lazy dogs.}\r
+\item{The \cemph{quick brown} fox \cemph{jumped over} the lazy dogs.}\r
+\end{ytemize}\r
+\item{plain word 4-grams}\r
+\begin{ytemize}\r
+\item{\cemph{The quick brown fox} jumped over the lazy dogs.}\r
+\item{The \cemph{quick brown fox jumped} over the lazy dogs.}\r
+\end{ytemize}\r
+\end{ytemize}\r
+\r
+\begin{table}\r
+\r
+\begin{center}\r
+\begin{tabular}{|l|r|r|r|r|}\r
+\hline\r
+\bf feature & \bf recall & \bf precision & \bf granularity & plagdet \\\r
+\hline\r
+plain 5-grams & 0.6306 & 0.8484 & 1.0000 & \cemph{0.7235} \\\r
+contextual 4-grams & 0.6721 & \cemph{0.8282} & 1.0000 & \cemph{0.7421} \\\r
+plain 4-grams & \cemph{0.7556} & 0.7340 & 1.0000 & \cemph{0.7447} \\\r
+\hline\r
+\end{tabular}\r
+\end{center}\r
+\r
+\caption{Comparison of contextual 4-grams and plain word 4-grams}\r
+\end{table}\r
+\r
+\subsection{Global Postprocessing}\r
+\r
+\begin{ytemize}\r
+\item{Similar to PAN 2010 \cite{Kasprzak2010}}\r
+\item{Overlapping detections removal}\r
+\item{\cemph{Result:} improvement, but not as big as in 2010}\r
+\end{ytemize}\r
+\r
%\r
% Spolecna cast\r
%\r
\r
\section{Conclusion}\r
\r
-Nějaký závěr\r
+\subsection{Candidate retrieval}\r
\r
-%%% References\r
+\begin{ytemize}\r
+\item{Second best ratio of recall to the number of queries}\r
+\item{Missing support for phrasal search in ChatNoir is a big stumbling block}\r
+\end{ytemize}\r
\r
-%% Note: use of BibTeX als works!!\r
+\subsection{Text alignment}\r
\r
-\bibliographystyle{plain}\r
-\begin{thebibliography}{1}\r
+\begin{ytemize}\r
+\item{Significant improvement against PAN 2013}\r
+\item{Word 4-grams are better than contextual 4-grams}\r
+\item{We need a better ranking system than plagdet!}\r
+\end{ytemize}\r
\r
-\bibitem{ISMU}\r
-\cemph{Masaryk University Information System}\\\r
-{\tt http://is.muni.cz/}, contact: {\tt iscor@fi.muni.cz}.\r
+%%% References\r
\r
-\bibitem{Theses}\r
-\cemph{Czech National Archive of Graduate Theses}\\\r
-{\tt http://theses.cz/}, contact: {\tt theses@fi.muni.cz}.\r
+%% Note: use of BibTeX als works!!\r
\r
-\bibitem{AWFC}\r
-\cemph{Sven Meyer Zu Eissen and Benno Stein: Intrinsic Plagiarism Detection}\\\r
-{\tt Proceedings of the European Conference on Information Retrieval (ECIR-06)}, {\tt 2006}\r
+\bibliographystyle{plain}\r
+\bibliography{pan13-notebook}\r
+\nocite{awfc}\r
\r
-\end{thebibliography}\r
+%\begin{thebibliography}{1}\r
+%\r
+%\bibitem{ISMU}\r
+%\cemph{Masaryk University Information System}\\\r
+%{\tt http://is.muni.cz/}, contact: {\tt iscor@fi.muni.cz}.\r
+%\r
+%\bibitem{Theses}\r
+%\cemph{Czech National Archive of Graduate Theses}\\\r
+%{\tt http://theses.cz/}, contact: {\tt theses@fi.muni.cz}.\r
+%\r
+%\bibitem{AWFC}\r
+%\cemph{Sven Meyer Zu Eissen and Benno Stein: Intrinsic Plagiarism Detection}\\\r
+%{\tt Proceedings of the European Conference on Information Retrieval (ECIR-06)}, {\tt 2006}\r
+%\r
+%\end{thebibliography}\r
\r
\smallskip\r
\hrule height .1em\r
\r
% \sffamily\r
\r
-QR kód?\r
\r
+\hbox to \hsize{\r
+ {\hsize=0.5\hsize\vbox{\r
\cemph{Contact information:}\\\r
- Šimon Suchomel {\tt suchomel@fi.muni.cz},\\\r
- Jan Kasprzak, {\tt kas@fi.muni.cz}.\r
-\r
+ Šimon Suchomel {\tt suchomel@fi.muni.cz}\\\r
+ Jan Kasprzak {\tt kas@fi.muni.cz}\\\r
+ {\cemph{\tt http://www.fi.muni.cz/\~{}kas/pan13/}}\r
+}\r
+ \hfill\r
+ {\hsize=0.4\hsize\vbox{\r
+ \includegraphics[width=\hsize]{qrcode.png}\r
+}}}}\r
+ \r
\r
\end{multicols}\r
\r
\end{document}\r
-\r
https://www.fi.muni.cz/~kas/git / pan13-paper.git / blobdiff