The ability to capture the temporal dimension of a natural language text is essential to many natural language processing applications, such as Question Answering, Automatic Summarisation, and Information Retrieval. Temporal processing is a ¯eld of Computational Linguistics which aims to access this dimension and derive a precise temporal representation of a natural language text by extracting time expressions, events and temporal relations, and then representing them according to a chosen knowledge framework. This thesis focuses on the investigation and understanding of the di®erent ways time is expressed in natural language, on the implementation of a temporal processing system in accordance with the results of this investigation, on the evaluation of the system, and on the extensive analysis of the errors and challenges that appear during system development. The ultimate goal of this research is to develop the ability to automatically annotate temporal expressions, verbal events and temporal relations in a natural language text. Temporal expression annotation involves two stages: temporal expression identi¯cation concerned with determining the textual extent of a temporal expression, and temporal expression normalisation which ¯nds the value that the temporal expression designates and represents it using an annotation standard. The research presented in this thesis approaches these tasks with a knowledge-based methodology that tackles temporal expressions according to their semantic classi¯cation. Several knowledge sources and normalisation models are experimented with to allow an analysis of their impact on system performance. The annotation of events expressed using either ¯nite or non-¯nite verbs is addressed with a method that overcomes the drawback of existing methods v which associate an event with the class that is most frequently assigned to it in a corpus and are limited in coverage by the small number of events present in the corpus. This limitation is overcome in this research by annotating each WordNet verb with an event class that best characterises that verb. This thesis also describes an original methodology for the identi¯cation of temporal relations that hold among events and temporal expressions. The method relies on sentence-level syntactic trees and a propagation of temporal relations between syntactic constituents, by analysing syntactic and lexical properties of the constituents and of the relations between them. The detailed evaluation and error analysis of the methods proposed for solving di®erent temporal processing tasks form an important part of this research. Various corpora widely used by researchers studying di®erent temporal phenomena are employed in the evaluation, thus enabling comparison with state of the art in the ¯eld. The detailed error analysis targeting each temporal processing task helps identify not only problems of the implemented methods, but also reliability problems of the annotated resources, and encourages potential reexaminations of some temporal processing tasks.

Este trabalho descreve EXTIO (Extraction of Temporal Information Using Ontologies), uma abordagem que permite a normalização de expressões temporais e a organização em ontologia de fatos temporais extraídos de texto em linguagem natural. Isto permite que motores de busca possam aproveitar melhor a informação temporal de páginas daWeb, realizando inferências sobre fatos temporais. EXTIO propõe: a normalização de expressões temporais relativas através de uma gramática formal para a língua inglesa; e a organização de fatos temporais extraídos do texto normalizado em uma ontologia. Expressões temporais relativas são construções textuais de tempo que se referem a uma data absoluta cujo valor é relativo a outra data. Por exemplo, a expressão “three months ago” (três meses atrás) é uma expressão temporal relativa, pois seu surgimento no texto se refere a uma data três meses antes da data de publicação do documento. Experimentos demonstram que a gramática formal proposta para a normalização de expressões temporais relativas supera o baseline na eficácia da normalização e no tempo de processamento de documentos em linguagem natural. A principal contribuição deste trabalho é a gramática formal para normalização de expressões temporais relativas de texto na língua inglesa. Também é contribuição deste trabalho o processamento semântico da informação temporal disponível em formato texto em documentos, para que possa ser melhor aproveitada por motores de busca. / This work describes EXTIO, an approach for the normalization of temporal expressions and the semantic organization of temporal facts extracted from natural language text. This approach allows search engines to benefit from temporal information in Web pages, performing inferences on temporal facts. EXTIO proposes: the normalization of relative temporal expressions through a formal grammar for the English language; and the organization of temporal facts extracted from normalized text in an ontology. Relative temporal expressions are textual time structures that refer to an absolute date whose value is relative to another date. For instance, “three months ago” is a relative temporal expression because its appearance in the text refers to a date three months before the document publication date. Experiments show that the proposed formal grammar for the normalization of relative temporal expressions has a better performance than the baseline in effectiveness and processing time. The main contribution of this work is the formal grammar for the normalization of temporal expressions in natural language text in English. Another contribution of this work is the semantic processing of temporal information available in documents, so that search engines may benefit from this information.

Este trabalho descreve EXTIO (Extraction of Temporal Information Using Ontologies), uma abordagem que permite a normalização de expressões temporais e a organização em ontologia de fatos temporais extraídos de texto em linguagem natural. Isto permite que motores de busca possam aproveitar melhor a informação temporal de páginas daWeb, realizando inferências sobre fatos temporais. EXTIO propõe: a normalização de expressões temporais relativas através de uma gramática formal para a língua inglesa; e a organização de fatos temporais extraídos do texto normalizado em uma ontologia. Expressões temporais relativas são construções textuais de tempo que se referem a uma data absoluta cujo valor é relativo a outra data. Por exemplo, a expressão “three months ago” (três meses atrás) é uma expressão temporal relativa, pois seu surgimento no texto se refere a uma data três meses antes da data de publicação do documento. Experimentos demonstram que a gramática formal proposta para a normalização de expressões temporais relativas supera o baseline na eficácia da normalização e no tempo de processamento de documentos em linguagem natural. A principal contribuição deste trabalho é a gramática formal para normalização de expressões temporais relativas de texto na língua inglesa. Também é contribuição deste trabalho o processamento semântico da informação temporal disponível em formato texto em documentos, para que possa ser melhor aproveitada por motores de busca. / This work describes EXTIO, an approach for the normalization of temporal expressions and the semantic organization of temporal facts extracted from natural language text. This approach allows search engines to benefit from temporal information in Web pages, performing inferences on temporal facts. EXTIO proposes: the normalization of relative temporal expressions through a formal grammar for the English language; and the organization of temporal facts extracted from normalized text in an ontology. Relative temporal expressions are textual time structures that refer to an absolute date whose value is relative to another date. For instance, “three months ago” is a relative temporal expression because its appearance in the text refers to a date three months before the document publication date. Experiments show that the proposed formal grammar for the normalization of relative temporal expressions has a better performance than the baseline in effectiveness and processing time. The main contribution of this work is the formal grammar for the normalization of temporal expressions in natural language text in English. Another contribution of this work is the semantic processing of temporal information available in documents, so that search engines may benefit from this information.

Este trabalho descreve EXTIO (Extraction of Temporal Information Using Ontologies), uma abordagem que permite a normalização de expressões temporais e a organização em ontologia de fatos temporais extraídos de texto em linguagem natural. Isto permite que motores de busca possam aproveitar melhor a informação temporal de páginas daWeb, realizando inferências sobre fatos temporais. EXTIO propõe: a normalização de expressões temporais relativas através de uma gramática formal para a língua inglesa; e a organização de fatos temporais extraídos do texto normalizado em uma ontologia. Expressões temporais relativas são construções textuais de tempo que se referem a uma data absoluta cujo valor é relativo a outra data. Por exemplo, a expressão “three months ago” (três meses atrás) é uma expressão temporal relativa, pois seu surgimento no texto se refere a uma data três meses antes da data de publicação do documento. Experimentos demonstram que a gramática formal proposta para a normalização de expressões temporais relativas supera o baseline na eficácia da normalização e no tempo de processamento de documentos em linguagem natural. A principal contribuição deste trabalho é a gramática formal para normalização de expressões temporais relativas de texto na língua inglesa. Também é contribuição deste trabalho o processamento semântico da informação temporal disponível em formato texto em documentos, para que possa ser melhor aproveitada por motores de busca. / This work describes EXTIO, an approach for the normalization of temporal expressions and the semantic organization of temporal facts extracted from natural language text. This approach allows search engines to benefit from temporal information in Web pages, performing inferences on temporal facts. EXTIO proposes: the normalization of relative temporal expressions through a formal grammar for the English language; and the organization of temporal facts extracted from normalized text in an ontology. Relative temporal expressions are textual time structures that refer to an absolute date whose value is relative to another date. For instance, “three months ago” is a relative temporal expression because its appearance in the text refers to a date three months before the document publication date. Experiments show that the proposed formal grammar for the normalization of relative temporal expressions has a better performance than the baseline in effectiveness and processing time. The main contribution of this work is the formal grammar for the normalization of temporal expressions in natural language text in English. Another contribution of this work is the semantic processing of temporal information available in documents, so that search engines may benefit from this information.

Bien que les travaux existants aient montré que les noms sans déterminant étaient particulièrement fréquents dans les syntagmes prépositionnels, les mécanismes régissant leur emploi dans les SP demeurent assez mal connus. Cette thèse présente les résultats d’une étude de corpus synchronique portant sur certains SP spatio-temporels sans déterminant de l’anglais et du français. Nous montrons que ces SP sont extrêmement hétérogènes sur le plan syntaxique, lexical, sémantique et pragmatique ; ils s’inscrivent sur un gradient allant d’expressions pleinement figées et opaques à des séquences transparentes, modifiables et productives. Nos données n’étayent pas l’hypothèse d’un phénomène unifié et strictement grammatical. Cependant, ces SP ne peuvent être simplement considérés comme une collection d’anomalies sans rapport les unes avec les autres ; certains d’entre eux appartiennent à des groupements productifs dans lesquels la syntaxe marquée va de pair avec un sens marqué. Les différences entre les SP anglais et français peuvent tenir soit à la productivité des groupements, soit à leurs caractéristiques sémantiques et/ou pragmatiques, qui reflètent la place et la saillance des noms sans déterminant dans les deux langues. Ce travail montre que l’application de l’analyse constructionnelle à ces SP éclaire leur intégration dans le système linguistique tout en permettant une typologie fine ; il suggère que des interactions plus importantes entre phraséologie et grammaire des constructions seraient particulièrement intéressantes pour l’étude des « moules » phraséologiques et des expressions polylexicales syntaxiquement marquées. / Although previous research has shown that bare nouns are particularly frequent in prepositional phrases, the mechanisms underlying their use in PPs remain a relatively understudied topic. This thesis presents the results of a synchronic, corpus-based analysis of several groups of English and French spatio-temporal PPs. The case studies show that determinerless PPs are syntactically, lexically, semantically and pragmatically highly heterogeneous, ranging from fully fixed, opaque expressions to transparent, modifiable and productive sequences. The corpus data does not support the hypothesis of a unified, strictly grammatical phenomenon. However, these PPs cannot be explained away as a mere collection of unrelated anomalies; some of them cluster into productive sub-groupings in which marked syntax correlates with marked meaning. The differences between the French and English PPs can pertain either to the productivity of the groupings, or to their semantic and/or pragmatic properties. In the latter case, the contrasts reflect the place and salience of bare noun constructions in each language. The application of constructional analysis to the PPs is shown to be an illuminating way of accounting for their integration into the linguistic system whilst allowing for a fine-grained typology. This thesis argues that a greater interaction between phraseology and construction grammar would be of particular interest for the study of phraseological “patterns” and syntactically marked multi-word constructs.