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<i>OLAP</i> users heavily rely on visualization of query answers for their interactive analysis of massive amounts of data. Very often, these answers cannot be visualized entirely and the user has to navigate through them to find relevant facts.In this paper, we propose a framework for personalizing <i>OLAP</i> queries. In this framework, the user is asked(More)
QRISTAL [10], [13] is a question answering system making intensive use of natural language processing both for indexing documents and extracting answers. This article describes the improvements of the system since last year. Then, it presents our benchmarked results for the CLEF 2008 campaign and a critical description of the system. Since Synapse(More)
Multidimensional databases have been designed to provide decision makers with the necessary tools to help them understand their data. This framework is different from transactional data as the datasets contain huge volumes of historicized and aggregated data defined over a set of dimensions that can be arranged through multiple levels of granularities. Many(More)
Views over databases have regained attention in the context of data warehouses, which are seen as materialized views. In this setting, efficient view maintenance is an important issue, for which the notion of self-maintainability has been identified as desirable. In this paper, we extend the concept of self-maintainability to (query and update) independence(More)
On-Line Analytical Processing (OLAP) provides an interactive query-driven analysis of multidimensional data based on a set of navigational operators like roll-up or slice and dice. In most cases, the analyst is expected to use these operations intuitively to find interesting patterns in a huge amount of data of high dimensionality.In this paper, we propose(More)
Association rule mining often requires the repeated execution of some extraction algorithm for different values of the support and confidence thresholds, as well as for different source datasets. This is an expensive process, even if we use the best existing algorithms. Hence the need for incremental mining, whereby mining results already obtained can be(More)
In the QA and information retrieval domains progress has been assessed via evaluation campaigns(Clef, Ntcir, Equer, Trec).In these evaluations, the systems handle independent questions and should provide one answer to each question, extracted from textual data, for both open domain and restricted domain. Quaero is a program promoting research and industrial(More)
We introduce a method for building an XML constraint validator from a given set of schema, key and foreign key constraints. The XML constraint val-idator obtained by our method is a bottom-up tree transducer that is used not only for checking, in only one pass, the correctness of an XML document but also for incrementally validating updates over this(More)
Algorithms for validation play a crucial role in the use of XML. Although much effort has been made for formalizing the treatment of elements, attributes have been neglected. This paper presents a validation model for XML documents that takes into account element and attribute constraints imposed by a given DTD. Our main contribution is the introduction of(More)