Re-BERT OQA : un système de question-réponse dans le domaine ouvert

RÉSUMÉ : Dans le présent mémoire, nous abordons la tâche de question-réponse dans le domaine ouvert, c’est-à-dire la tâche qui a pour but de répondre à une question en utilisant son corpus de connaissances (qu’il soit structuré ou non) comme seule ressource. Plus spécifiquement notre but est de proposer un système de question-réponse dans le domaine ouvert capable de répondre à des questions factuelles en utilisant Wikipédia comme corpus de connaissances. En général, ce genre de système se divise en deux modules. Le premier, responsable de la recherche d’information, permet de trouver des documents pertinents dans le corpus de connaissance. Le second, le module d’extraction de réponse, a pour objectif d’extraire des candidats de réponse provenant des documents précédemment sélectionnés puis de déterminer une réponse finale parmi les candidats. Dans les dernières années, les avancées dans le domaine de la compréhension de lecture automatique ont été une grande source d’inspiration pour le module d’extraction résultant en la création des systèmes de question-réponse dans le domaine ouvert les plus efficaces à ce jour.----------ABSTRACT : In this thesis, we tackle the Open Domain Question-Answering task, where the goal is to be able to answer a question using a knowledge source (either structured like DBpedia or unstructured such as Wikipedia). Specifically, our goal is to propose an open domain questionanswering system capable of answering factoid questions using Wikipedia as knowledge source. In general, these types of systems are divided in two sub-modules. The first one, responsible of the information retrieval step, enables the system to find relevant documents in its knowledge source. The second, the answer extraction module, extracts answer candidates from the previously selected documents and then determines the final answer within the candidates. In recent years, the progress achieved in the machine reading comprehension field has driven the development of improved answer extraction modules resulting in the creation of the best open domain question answering systems to date

Bound states of edge dislocations: The quantum dipole problem in two dimensions

We investigate bound state solutions of the 2D Schr\"odinger equation with a dipole potential originating from the elastic effects of a single edge dislocation. The knowledge of these states could be useful for understanding a wide variety of physical systems, including superfluid behavior along dislocations in solid $^4$He. We present a review of the results obtained by previous workers together with an improved variational estimate of the ground state energy. We then numerically solve the eigenvalue problem and calculate the energy spectrum. In our dimensionless units, we find a ground state energy of -0.139, which is lower than any previous estimate. We also make successful contact with the behavior of the energy spectrum as derived from semiclassical considerations.Comment: 6 pages, 3 figures, submitted to PR

Progress of the LUNEX5 Project

http://accelconf.web.cern.ch/AccelConf/FEL2013/papers/wepso05.pdfInternational audienceLUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, and coherent pulses in the soft X-ray region. A 400 MeV superconducting linear accelerator and a laser wakefield accelerator (LWFA), will feed a single Free Electron Laser line with High order Harmonic in Gas and Echo Enable Harmonic Generation seeding. After the Conceptual Design Report (CDR), R&D has been launched on specific magnetic elements (cryo-ready 3 m long in-vacuum undulator, a variable strong permanent magnet quadrupoles), on diagnostics (Smith-Purcell, electro-optics). In recent transport studies of a LWFA based on more realistic beam parameters (1 % energy spread, 1 μm beam size and 1 mrad divergence) than the ones assumed in the CDR, a longitudinal and transverse manipulation enables to provide theoretical amplification. A test experiment is under preparation. It is noted in this context that among the French scientific community's interest in experiments at operating FELs is increasing

LUNEX5: A French FEL Test Facility Light Source Proposal

http://accelconf.web.cern.ch/AccelConf/IPAC2012/papers/tuppp005.pdfInternational audienceLUNEX5 is a new Free Electron Laser (FEL) source project aimed at delivering short and coherent X-ray pulses to probe ultrafast phenomena at the femto-second scale, to investigate extremely low density samples as well as to image individual nm scale objects

The LUNEX5 project

http://accelconf.web.cern.ch/AccelConf/FEL2012/papers/froa03.pdfInternational audienceLUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, and coherent pulses in the soft X-ray region. The project consists of a Free Electron Laser (FEL) line enabling the most advanced seeding configurations: High order Harmonic in Gas (HHG) seeding and Echo Enable Harmonic Generation (EEHG) with in-vacuum (potentially cryogenic) undulators of 15 and 30 mm period. Two accelerator types feed this FEL line : a 400 MeV Conventional Linear Accelerator (CLA) using superconducting cavities compatible with a future upgrade towards high repetition rate, for the investigations of the advanced FEL schemes; and a 0.4 - 1 GeV Laser Wake Field Accelerator (LWFA), to be qualified in view of FEL application, in the single spike or seeded regime. Two pilot user experiments for timeresolved studies of isolated species and solid state matter dynamics will take benefit of LUNEX5 FEL radiation and provide feedback of the performance of the different schemes under real user conditions

Accelerator Physics Code Web Repository

In the framework of the CARE HHH European Network, we have developed a web-based dynamic acceleratorphysics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking

Local Government Revenue Mobilisation in Anglophone Africa

This paper examines opportunities and constraints facing local revenue mobilisation in anglophone Africa, with an emphasis on urban settings. It discusses specific revenue instruments and their effects on economic efficiency, income distribution and accountability. In particular, it addresses political and administrative constraints facing various revenue instruments and factors affecting citizens’ compliance. The analysis is illustrated with examples from across anglophone Africa. A general conclusion emerging from the study is that local revenues mobilised in most local government authorities in Africa are necessary but not sufficient to develop and supply adequate services for the fast-growing population. On this basis, areas for further research on local government revenue mobilisation in Africa are identifiedDfI

Accelerator physics code web repository

In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this repository, illustrate its usage, and discuss our future plans, with emphasis on code benchmarking