IREEL: remote experimentation with real protocols and applications over emulated network

This paper presents a novel e-learning platform called IREEL. IREEL is a virtual laboratory allowing students to drive experiments with real Internet applications and end-to-end protocols in the context of networking courses. This platform consists in a remote network emulator offering a set of predefined applications and protocol mechanisms. Experimenters configure and control the emulation and the end-systems behavior in order to perform tests, measurements and observations on protocols or applications operating under controlled specific networking conditions. A set of end-to-end mechanisms, mainly focusing on transport and application level protocols, are currently available. IREEL is scalable and easy to use thanks to an ergonomic web interface

On the role of computers in creativity-support systems

We report here on our experiences with designing computer-based creativity-support systems over several years. In particular, we present the design of three different systems incorporating different mechanisms of creativity. One of them uses an idea proposed by Rodari to stimulate imagination of the children in writing a picture-based story. The second one is aimed to model creativity in legal reasoning, and the third one uses low-level perceptual similarities to stimulate creation of novel conceptual associations in unrelated pictures.We discuss lessons learnt from these approaches, and address their implications for the question of how far creativity can be tamed by algorithmic approaches

Investigation of the electron emission properties of Silver: from exposed to ambient atmosphere Ag surface to ion-cleaned Ag surface

International audienceElectron emission properties of materials are highly dependent to the surface and the first nanometres subsurface. Technical materials, i.e used within applications are ordinarily exposed to atmosphere, which interacts with the surface. The contamination layer building up at the surface of materials and/or oxidation layer affects dramatically the electron emission proprieties. In this paper, starting from 99.99% pure silver sample, exposed 4 years to ambient atmosphere, we monitored the variations of the electron emission properties and the surface composition during step by step ion etching procedure

Calculation of the angular dependence of the total electron yield

Secondary electron emission plays an important role in many applic. ations such as scanning electron microscopy, space applications and accelerator technologies. Secondary electron yield delta(E)at normal incidence of a primary electron beam is frequently modelled by the well-known semi-empirical law. However, this model is not used in a consistent way to predict the angular dependence. Additionally, neglecting the energy reflection has particular influence on the angular dependence of the secondary electron yield and therefore cannot be ignored. We propose here a simple approach to calculate delta(E) for any incident angle based on the experimental result achieved at normal incidence. The secondary electron yield is calculated according to the universal semi-empirical law, while a fraction of the electron energy deposited into the sample is calculated using a Monte Carlo simulation. A simple modification of the original model for calculating a total electron yield (i.e. the sum of the true secondaries and backscattered electrons) is also presented. Very good agreement is observed between measurements and the calculation as long as the roughness is not significant The model works very well for both, low Z and high Z materials. In the case of rough samples this approach cannot predict the angular dependence of the total electron yield. (C) 2015 Elsevier Ltd. All rights reserved.Joint Meeting on the 13th European Vacuum Conference / 7th European Topical Conference on Hard Coatings / 9th Iberian Vacuum Meeting, Sep 08-12, 2014, Aveiro, Portuga

Un nouveau moyen expérimental de mesure de rendement de rétrodiffusion

National audienceUn moyen expérimental permettant de caractériser l'émission électronique sous irradiation par des électrons (flux, énergies) a été développé. Une technique originale a été implanté dans l'objectif d'identifier et quantifier le type d'électrons émis: secondaire ou rétrodiffusé. Les résultats obtenus sont en bon accord avec la littérature