Computing Trees of Named Word Usages from a Crowdsourced Lexical Network

Thanks to the participation of a large number of persons via web-based games, a large-sized evolutionary lexical network is available for French. With this resource, we tackled the question of the determination of the word usages of a term, and then we introduced the notion of similarity between these various word usages. So, for a given term, we were able to build its word usage tree: the root groups together all its possible usages and a search in the tree corresponds to a refinement of these word usages. The labelling of the various nodes of the word usage tree of a term is made during a breadth-first search: the root is labelled by the term itself and each node of the tree is labelled by a term stemming from the clique or quasi-clique this node represents. We show on a precise example that it is possible that some nodes of the tree, often leaves, cannot be labelled without ambiguity. This paper ends with an evaluation about word usages detected in our lexical network.

Optimized physical recovery of DNAPL using upwelling technique and geostatistical analysis at large field scale

International audienceBackground/Objectives. The site is a large chloralcali chemical plant located in the centre-east of France. From the 1980s to 2007, a several hectares historical DNAPL pool was physically confined while migration was monitored. The DNAPL has rapidly migrated from a landfill and reached a static state within a shallow water-table sandy aquifer at top of a clayey unit at 10 meters depth. Thicknesses of DNAPL have been observed from 20 cm to 150 cm according to substratum morphology. Migration of DNAPL has been controlled by two water pumping wells for thirty years making a water depression in the area and inverse gradient. The average flow-rate of the hydraulic confinement is 40 m3/h. The DNAPL is composed of a mixture of heavy perchlorinated compounds, mainly hexchlorobutadiene (50%), hexachloroethane (10%), perchlorethylene, carbon tetrachloride and hexachlorobenzene. The continental climate at the site, with cold winters, adds major constraints due to crystallization of hexachlorobenzene in the mixture. After a review of several DNAPL recovery strategies, various pumping techniques were selected for testing and then implemented in the field. These methods include batch DNAPL pumping with and without water pumping and batch DNAPL pumping with vacuum. Approach/Activities. Location of DNAPL pumping stations was optimized after implementation of drillings and a geostatistical analysis. This revealed interesting features of DNAPL accumulation at the top of the substratum, such as a main flow channel and connected and disconnected basins. A non-enhanced low-flow batch pumping of DNAPL demonstrated that DNAPL could be recovered continuously at the beginning of the experiment (100 l/h). After a while, a lack of product feeding was observed at the pumping site revealing a threshold pumping rate (5 l/h) caused by weir effects (partially disconnected basin) of the substratum morphology. This demonstrated the limits of batch-pumping stations located above disconnected DNAPL basins. Results/Lessons Learned. When using hydraulic upwelling technique, during the pumping phase, water is pumped at a constant rate of 15 m3/h while DNAPL is continuously pumped with an average rate of 20 l/h. The pumping set leads to DNAPL upconing of 0,30 m while water level decrease by 3 meters. After both pumping ceased, DNAPL recovered to the initial interface static level after 50 hours while water level recover static level almost instantaneously. Water pumping induces a pressure gradient around the well that forces the DNAPL to flow at a higher rate towards the screened well without disconnecting small pools of product. Local pneumatic (vaccum) are being experimented at moment and are demonstrated good results. In order to improve the physical recovery of DNAPL, the optimized techniques implemented in the field tripling the yearly recovery rate between 2008 and 2013 to reach 200 tons

SPAM : a multiprocessor execution driven simulation Kernel

Trace driven simulation is a well known technique for performance evaluation of single processor computers. However, trace driven simulation introduces distortions when used to simulate multiprocessor architectures. Execution driven simulation is the only technique that gives accurate simulation results for multiprocessor architectures though it is difficult to implement. Thisd paper presents SPAM, a simulation kernel that simplifies the construction of execution driven simulators for shared memory multiprocessors. The kernel provides a tracing tool and a set of primitives which allow the execution, tracing and simulation of shared memory parallel applications on a single processor computer. The performance of the kernel allows the simulation of real sized parallel applications in a reasonnable time

Modalités et techniques modernes du diagnostic expérimental de la peste bovine

Les auteurs font le point sur les techniques de diagnostic susceptibles d'éradiquer la peste bovine d'Afrique. Ils passent en revue les étapes d'un bon diagnostic expérimental : Les méthodes de prélèvement, le choix des réactions et leur conduite, la réalisation du diagnosti

Si beaucoup d'oiseaux volent, peut-on en déduire que tous les oiseaux volent ? Production endogène de règles déductives dans un réseau lexico-sémantique

International audienceEndogenous production of deductive rules in a lexical-semantic network With a lexical-semantic network, it is possible to discover rule inductively from known facts. These rules are instrumental in reducing missing information in the network. In order to minimize emergence of relations that could be erroneous, we approached the question of polysemy and a filtering on rules presenting exceptions is realized.A partir d'un réseau lexico-sémantique, il est possible de générer des règles de façon inductive à partir des faits présents. Ces règles permettent de densifier le réseau et d'en réduire les silences. Afin de minimiser l'émergence de relations qui pourraient être erronées, la question de la polysémie est abordée et un filtrage sur les règles présentant des exceptions est réalisé