360 research outputs found
Concept-based Interactive Query Expansion Support Tool (CIQUEST)
This report describes a three-year project (2000-03) undertaken in the Information Studies
Department at The University of Sheffield and funded by Resource, The Council for
Museums, Archives and Libraries. The overall aim of the research was to provide user
support for query formulation and reformulation in searching large-scale textual resources
including those of the World Wide Web. More specifically the objectives were: to investigate
and evaluate methods for the automatic generation and organisation of concepts derived from
retrieved document sets, based on statistical methods for term weighting; and to conduct
user-based evaluations on the understanding, presentation and retrieval effectiveness of
concept structures in selecting candidate terms for interactive query expansion.
The TREC test collection formed the basis for the seven evaluative experiments conducted in
the course of the project. These formed four distinct phases in the project plan. In the first
phase, a series of experiments was conducted to investigate further techniques for concept
derivation and hierarchical organisation and structure. The second phase was concerned with
user-based validation of the concept structures. Results of phases 1 and 2 informed on the
design of the test system and the user interface was developed in phase 3. The final phase
entailed a user-based summative evaluation of the CiQuest system.
The main findings demonstrate that concept hierarchies can effectively be generated from
sets of retrieved documents and displayed to searchers in a meaningful way. The approach
provides the searcher with an overview of the contents of the retrieved documents, which in
turn facilitates the viewing of documents and selection of the most relevant ones. Concept
hierarchies are a good source of terms for query expansion and can improve precision. The
extraction of descriptive phrases as an alternative source of terms was also effective. With
respect to presentation, cascading menus were easy to browse for selecting terms and for
viewing documents. In conclusion the project dissemination programme and future work are
outlined
Toponym Disambiguation in Information Retrieval
In recent years, geography has acquired a great importance in the context of
Information Retrieval (IR) and, in general, of the automated processing of
information in text. Mobile devices that are able to surf the web and at the
same time inform about their position are now a common reality, together
with applications that can exploit this data to provide users with locally
customised information, such as directions or advertisements. Therefore,
it is important to deal properly with the geographic information that is
included in electronic texts. The majority of such kind of information is
contained as place names, or toponyms.
Toponym ambiguity represents an important issue in Geographical Information
Retrieval (GIR), due to the fact that queries are geographically constrained.
There has been a struggle to nd speci c geographical IR methods
that actually outperform traditional IR techniques. Toponym ambiguity
may constitute a relevant factor in the inability of current GIR systems to
take advantage from geographical knowledge. Recently, some Ph.D. theses
have dealt with Toponym Disambiguation (TD) from di erent perspectives,
from the development of resources for the evaluation of Toponym Disambiguation
(Leidner (2007)) to the use of TD to improve geographical scope
resolution (Andogah (2010)). The Ph.D. thesis presented here introduces
a TD method based on WordNet and carries out a detailed study of the
relationship of Toponym Disambiguation to some IR applications, such as
GIR, Question Answering (QA) and Web retrieval.
The work presented in this thesis starts with an introduction to the applications
in which TD may result useful, together with an analysis of the
ambiguity of toponyms in news collections. It could not be possible to
study the ambiguity of toponyms without studying the resources that are
used as placename repositories; these resources are the equivalent to language
dictionaries, which provide the di erent meanings of a given word.Buscaldi, D. (2010). Toponym Disambiguation in Information Retrieval [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8912Palanci
Cogex: A semantically and contextually enriched logic prover for question answering
AbstractThis paper presents the architecture and functionality of a logic prover designed for question answering. The approach transforms questions and answer passages into logic representations based on syntactic, semantic and contextual information. World knowledge supplements the linguistic, ontological, and temporal axioms supplied to the prover which renders a deep understanding of the relationship between the question and answer text. The trace of the proofs provides a basis for generating human comprehensible answer justifications. The results show that the prover boosts the performance of the Question Answering system on TREC 2004 questions by 12%
Designing Semantic Kernels as Implicit Superconcept Expansions
Recently, there has been an increased interest in the exploitation of background knowledge in the context of text mining tasks, especially text classification. At the same time, kernel-based learning algorithms like Support Vector Machines have become a dominant paradigm in the text mining community. Amongst other reasons, this is also due to their capability to achieve more accurate learning results by replacing standard linear kernel (bag-of-words) with customized kernel functions which incorporate additional apriori knowledge. In this paper we propose a new approach to the design of ‘semantic smoothing kernels’ by means of an implicit superconcept expansion using well-known measures of term similarity. The experimental evaluation on two different datasets indicates that our approach consistently improves performance in situations where (i) training data is scarce or (ii) the bag-ofwords representation is too sparse to build stable models when using the linear kernel
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