Rule Based Plagiarism Detection using Information Retrieval - Notebook for PAN at CLEF 2011

This paper reports about the development of a Plagiarism detection system as a part of the Plagiarism detection task in PAN 2011. The external plagiarism detection problem has been solved with the help of Nutch, an open source Information Retrieval (IR) system. The system contains three phases – knowledge preparation, candidate retrieval and plagiarism detection. From the source documents, knowledge base has been prepared for developing the Nutch index and the queries have been formed from the suspicious documents for submission to the Nutch IR system. The retrieved candidate source sentences are assigned similarity scores by Nutch. Dissimilarity score is assigned for each candidate sentence and the suspicious sentence. Each candidate source sentence is ranked based on these two scores. The top ranked candidate sentence is selected for each suspicious sentence.