José R. Pérez-Agüera

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Query expansion is a well known method to improve the performance of information retrieval systems. In this work we have tested different approaches to extract the candidate query terms from the top ranked documents returned by the first-pass retrieval. One of them is the cooccurrence approach, based on measures of cooccurrence of the candidate and the(More)
This document describes the BM25 and BM25F implementation using the Lucene Java Framework. The implementation described here can be downloaded from [Pérez-Iglesias 08a]. Both models have stood out at TREC by their performance and are considered as stateof-the-art in the IR community. BM25 is applied to retrieval on plain text documents, that is for(More)
Nowadays, searching information in the web or in any kind of document collection has become one of the most frequent activities. However, user queries can be formulated in a way that hinder the recovery of the requested information. The objective of automatic query transformation is to improve the quality of the recovered information. This paper describes a(More)
Nowadays, searching information in the web or in any kind of document collection has become one of the most frequent activities. However, user queries can be formulated in a way that hinders the recovery of the requested information. The objective of automatic query transformation is to improve the quality of the recovered information. This paper describes(More)
This paper presents a new collection based on DBpedia and INEX for evaluating semantic search performance. The proposed corpus is used to calculate the impact of considering document's structure on the retrieval performance of the Lucene and BM25 ranking functions. Results show that BM25 outperforms Lucene in all the considered metrics and that there is(More)
In this paper we deal with two issues. First, we discuss the negative effects of term correlation in query expansion algorithms, and we propose a novel and simple method (query clauses) to represent expanded queries which may alleviate some of these negative effects. Second, we discuss a method to optimize local query-expansion methods using genetic(More)
The Delphi protocol is applied when a community of experts is required to reach a consensus and to deliver an answer. In these cases, consensus stands for reaching an agreement among the experts about what the answer should be. This consensus reaching problem has been already considered in the literature, though its automatisation remains as a challenge.(More)
With the increase in the use of mark-up languages, the classic IR models have been extended in order to be applied to structured documents. Generally these adaptations have been carried out by weighting the fields that form the document structure, and making the assumption of statistics independence between fields, forcing to an estimation of(More)