The relative ineffectiveness of information retrieval systems is largely caused by the inaccuracy with which a query formed by a few keywords models the actual user information need. One well known method to overcome this limitation is automatic query expansion (AQE), whereby the user’s original query is augmented by new features with a similar meaning. AQE has a long history in the information retrieval community but it is only in the last years that it has reached a level of scientific and experimental maturity, especially in laboratory settings such as TREC. This survey presents a unified view of a large number of recent approaches to AQE that leverage various data sources and employ very different principles and techniques. The following questions are addressed. Why is query expansion so important to improve search effectiveness? What are the main steps involved in the design and implementation of an AQE component? What approaches to AQE are available and how do they compare? Which issues must still be resolved before AQE becomes a standard component of large operational information retrieval systems (e.g., search engines)?

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A Survey of Automatic Query Expansion in Information Retrieval

This paper examines the meaning of context in relation to ontology based query expansion and contains a review of query expansion approaches. The various query expansion approaches include relevance feedback, corpus dependent knowledge models and corpus independent knowledge models. Case studies detailing query expansion using domain-specific and domain-independent ontologies are also included. The penultimate section attempts to synthesise the information obtained from the review and provide success factors in using an ontology for query expansion. Finally the area of further research in applying context from an ontology to query expansion within a newswire domain is described.

A review of ontology based query expansion

Semantic search has been one of the motivations of the semantic Web since it was envisioned. We propose a model for the exploitation of ontology-based knowledge bases to improve search over large document repositories. In our view of information retrieval on the semantic Web, a search engine returns documents rather than, or in addition to, exact values in response to user queries. For this purpose, our approach includes an ontology-based scheme for the semiautomatic annotation of documents and a retrieval system. The retrieval model is based on an adaptation of the classic vector-space model, including an annotation weighting algorithm, and a ranking algorithm. Semantic search is combined with conventional keyword-based retrieval to achieve tolerance to knowledge base incompleteness. Experiments are shown where our approach is tested on corpora of significant scale, showing clear improvements with respect to keyword-based search

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An Adaptation of the Vector-Space Model for Ontology-Based Information Retrieval

Word sense disambiguation (WSD) is traditionally considered an AI-hard problem. A break-through in this field would have a significant impact on many relevant Web-based applications, such as Web information retrieval, improved access to Web services, information extraction, etc. Early approaches to WSD, based on knowledge representation techniques, have been replaced in the past few years by more robust machine learning and statistical techniques. The results of recent comparative evaluations of WSD systems, however, show that these methods have inherent limitations. On the other hand, the increasing availability of large-scale, rich lexical knowledge resources seems to provide new challenges to knowledge-based approaches. In this paper, we present a method, called structural semantic interconnections (SSI), which creates structural specifications of the possible senses for each word in a context and selects the best hypothesis according to a grammar G, describing relations between sense specifications. Sense specifications are created from several available lexical resources that we integrated in part manually, in part with the help of automatic procedures. The SSI algorithm has been applied to different semantic disambiguation problems, like automatic ontology population, disambiguation of sentences in generic texts, disambiguation of words in glossary definitions. Evaluation experiments have been performed on specific knowledge domains (e.g., tourism, computer networks, enterprise interoperability), as well as on standard disambiguation test sets.

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Structural semantic interconnections: a knowledge-based approach to word sense disambiguation

Text document clustering plays an important role in providing intuitive navigation and browsing mechanisms by organizing large amounts of information into a small number of meaningful clusters. The bag of words representation used for these clustering methods is often unsatisfactory as it ignores relationships between important terms that do not co-occur literally. In order to deal with the problem, we integrate background knowledge — in our application Wordnet — into the process of clustering text documents. We cluster the documents by a standard partitional algorithm. Our experimental evaluation on Reuters newsfeeds compares clustering results with pre-categorizations of news. In the experiments, improvements of results by background knowledge compared to the baseline can be shown for many interesting tasks.

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WordNet improves text document clustering

The classical, vector space model for text retrieval is shown to give better results (up to 29% better in our experiments) if WordNet synsets are chosen as the indexing space, instead of word forms. This result is obtained for a manually disambiguated test collection (of queries and documents) derived from the Semcor semantic concordance. The sensitivity of retrieval performance to (automatic) disambiguation errors when indexing documents is also measured. Finally, it is observed that if queries are not disambiguated, indexing by synsets performs (at best) only as good as standard word indexing.

Indexing with WordNet synsets can improve text retrieval.

Indexing with WordNet synsets can improve Text Retrieval

This paper summarizes the goals, organization, and results of the second RepLab competitive evaluation campaign for Online Reputation Management Systems RepLab 2013. RepLab focused on the process of monitoring the reputation of companies and individuals, and asked participant systems to annotate different types of information on tweets containing the names of several companies: first tweets had to be classified as related or unrelated to the entity; relevant tweets had to be classified according to their polarity for reputation Does the content of the tweet have positive or negative implications for the reputation of the entity?, clustered in coherent topics, and clusters had to be ranked according to their priority potential reputation problems had to come first. The gold standard consists of more than 140,000 tweets annotated by a group of trained annotators supervised and monitored by reputation experts.

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Overview of RepLab 2013: Evaluating Online Reputation Monitoring Systems

This paper describes the organisation and results of RepLab 2014, the third competitive evaluation campaign for Online Reputation Management systems. This year the focus lied on two new tasks: reputation dimensions classification and author profiling, which complement the aspects of reputation analysis studied in the previous campaigns. The participants were asked (1) to classify tweets applying a standard typology of reputation dimensions and (2) categorise Twitter profiles by type of author as well as rank them according to their influence. New data collections were provided for the development and evaluation of systems that participated in this benchmarking activity.

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Overview of RepLab 2014: Author Profiling and Reputation Dimensions for Online Reputation Management

We present an approach to cross-language text retrieval based on the EuroWordNet (EWN) multilingual semantic database. EuroWordNet is a multilingual, WordNet-like database with basic semantic relations between words for several European languages (English, Dutch, Spanish, Italian, German, French, Czech, and Estonian). In addition to the relations in WordNet 1.5, EWN includes domain labels, cross-language, and cross-part-of-speech relations, which are directly useful for multilingual information retrieval. In our approach, documents in any language covered by EuroWordNet are indexed in a space of language-independent concepts (the EuroWordNet Inter Lingual Index), thus turning term weighting and query/document matching into language-independent tasks. We report on the results of a number of experiments that measure the potential benefits of the approach and its tolerance to word sense disambiguation errors. In our monolingual experiments, the classical, vector space model for text retrieval is shown to giv...

Irina Chugur

Papers

Indexing with WordNet synsets can improve text retrieval.

Indexing with WordNet synsets can improve Text Retrieval

Overview of RepLab 2013: Evaluating Online Reputation Monitoring Systems

Overview of RepLab 2014: Author Profiling and Reputation Dimensions for Online Reputation Management

Using eurowordnet in a concept-based approach to cross-language text retrieval