A Rhetorical Structuring Model for Natural Language Generation in Human-Computer Multi-Party Dialogue

Multi-party human-computer dialogue research is still in its infancy. Most of the research in this respect either addresses dialogues between pairs of computers, or performs studies on multi-party human dialogue corpora, in order to better understand this type of interaction. Thus, there are only a few computational models for this type of linguistic interaction and this paper tries to fill this gap. However, only the issue of generating linguistically-appropriate speech turns in multi-party dialogue will be addressed here. For this, a formal framework that accounts for multi-party dialogue situations is developed. Then this model is customized, so that only the point of view of the machine is considered. Finally, several particularly interesting multi-party dialogue situations (for service-oriented systems) are enforced with algorithms for rhetorical structure updating for answer generation, in natural language, and evaluated on concrete multi-party dialogue examples

Spectrum of Galactic Cosmic Rays Accelerated in Supernova Remnants

The spectra of high-energy protons and nuclei accelerated by supernova remnant shocks are calculated taking into account magnetic field amplification and Alfvenic drift both upstream and downstream of the shock for different types of supernova remnants during their evolution. The maximum energy of accelerated particles may reach $5\cdot10^{18}$ eV for Fe ions in Type IIb SNRs. The calculated energy spectrum of cosmic rays after propagation through the Galaxy is in good agreement with the spectrum measured at the Earth.Comment: 9 pages, 3 figures, accepted to Ap

Measuring the Effect of Discourse Structure on Sentiment Analysis

International audienceThe aim of this paper is twofold: measuring the effect of discourse structure when assessing the overall opinion of a document and analyzing to what extent these effects depend on the corpus genre. Using Segmented Discourse Representation Theory as our formal framework, we propose several strategies to compute the overall rating. Our results show that discourse-based strategies lead to better scores in terms of accuracy and Pearson’s correlation than state-of-the-art approaches

Sentiment Composition Using a Parabolic Model

International audienceIn this paper, we propose a computational model that accounts for the effects of negation and modality on opinion expressions. Based on linguistic experiments informed by native speakers, we distil these effects according to the type of modality and negation. The model relies on a parabolic representation where an opinion expression is represented as a point on a parabola. Negation is modelled as functions over this parabola whereas modality through a family of parabolas of different slopes; each slope corresponds to a different certainty degree. The model is evaluated using two experiments, one involving direct strength judgements on a 7-point scale and the other relying on a sentiment annotated corpus. The empirical evaluation of our model shows that it matches the way humans handle negation and modality in opinionated sentence

Et Trajan traversa le Danube

Notre dossier traite de la mise en place des infrastructures nécessaires à la préparation des campagnes de Trajan en Dacie, à la traversée de la frontière, enfin à la sécurisation de la ligne du Danube inférieur. Il s’agit, donc, de présenter une histoire des travaux routiers, notamment la fin du chantier des Portes de Fer et la connexion avec le reste de la voie danubienne, doublée par les ports de la flotte de Mésie. Pour ce qui est du passage du fleuve, et la première campagne, nous allons évoquer, en particulier, le rôle des têtes de pont, des grands camps en terre qui permettent la concentration des troupes, des ponts et des premières voies au nord du Danube. Enfin, la période entre les deux campagnes, la chute du royaume dace et le début de la province, voit la mise en place d’un réseau de camps, parfois bâtis en pierre, reliés par des voies au pont de Pontes – Drobeta

Evaluation in Discourse: a Corpus-Based Study

This paper describes the CASOAR corpus, the first manually annotated corpus that explores the impact of discourse structure on sentiment analysis with a study of movie reviews in French and in English as well as letters to the editor in French. While annotating opinions at the expression, the sentence or the document level is a well-established task and relatively straightforward, discourse annotation remains difficult, especially for non-experts. Therefore, combining both annotations poses several methodological problems that we address here. We propose a multi-layered annotation scheme that includes: the complete discourse structure according to the Segmented Discourse Representation Theory, the opinion orientation of elementary discourse units and opinion expressions, and their associated features. We detail each layer, explore the interactions between them and discuss our results. In particular, we examine the correlation between discourse and semantic category of opinion expressions, the impact of discourse relations on both subjectivity and polarity analysis and the impact of discourse on the determination of the overall opinion of a document. Our results demonstrate that discourse is an important cue for sentiment analysis, at least for the corpus genres we have studied

Applications of stability criteria to time delay systems

Stability and stabilization of time delay systems (even of the linear ones) is again in the mainstream of the research. A most recent example is the stability analysis of feedback control loops containing a first order controlled object with pure delay and a standard PID controller, thus generating a system with a second degree quasi-polynomial as characteristic equation. Since the classical memoir of Čebotarev and Meiman (1949) up to the more recent monographs by Stepan (1989) and Górecki et al (1989) several approaches to this problem have been given, aiming to find the most complete Routh-Hurwitz type conditions for this case. In fact the main problem is here a missing case in the original memoir of Čebotarev and Meiman and its significance within the framework of the most recent analysis of Górecki et al. The present paper aims to a fairly complete analysis of the problem combined with some hints for the nonlinear case (Aizerman problem). State feedback stabilization based on Artstein reduction of a system with input delay to a system without delay is also considered