Showing papers by "Denis Gillet published in 2006"

Strategy for the Control of a Dual-stage Nano-positioning System with a Single Metrology

Abstract: A double-stage feedback control structure for a double-stage mechanical system, with a single optical metrology is developed to reach nanometer accuracy at high bandwidth over large displacements. A piezoelectric stack actuator is used for fine positioning, while a permanent magnet (PM) stepper motor handles the coarse positioning. Two different control approaches are compared for driving the PM stepper motor, while a classical PID controller is designed to drive the piezoelectric actuator. Since only a single measurement device is used, the references for both control loops (fine and coarse) must be appropriately obtained. An adequate control structure including a partial observer is designed so as to take into account the influence of the fine actuator on the position estimation of the coarse actuator. The complete control mechanism and strategy ensure the tracking of the real reference with sufficient accuracy and bandwidth.

Awareness: An Enabling Feature for mediated Interaction in Communities of Practise

Abstract: The Ecole Polytechnique Federale de Lausanne (EPFL) is currently using a Web-based experimentation environment to support laboratory activities in engineering education. The key service for the acceptance of the learning modalities and the appropriation of the environment by the students is a shared electronic notebook called the eJournal. This service is not only used by students to perform the required laboratory work; it is also used to sustain collaboration between students. Additionally it provides support for exchanges with other services integrated in the learning environment. By tracking the creation, the exchanges and the tagging of the digital assets stored in the eJournal database, awareness can be provided. This position paper presents how the eJournal and the associated awareness features are currently enhanced to effectively support interaction in laboratory-oriented communities of practice for members using either desktop or mobile client devices.

Framework for Sustaining Collaboration in Laboratory-Oriented Communities of Practice

Abstract: This paper presents a Web-based collaboration framework designed for sustaining laboratory-oriented activities carried out within academic communities of practice. This framework relies on a Web-based collaboration environment designed as an electronic notebook; such journaling resources being commonly used in laboratory activities for collecting data and thoughts, keeping analyses and notes, as well as sharing information and results. Many electronic notebook systems exist. They are however mostly domain-oriented, such as the ejournal environment developed at the Ecole Polytechnique Federale de Lausanne (EPFL) to support collaborative experimentation in engineering education or the Collaboratories supporting experimental research in specific natural science areas. The new version of the ejournal introduced in this paper, namely the CoPs ejournal, aims at overcoming this limitation by focusing more on the context and the community. The CoPs ejournal has been developed jointly by the EPFL and the HE-Arc Ingenierie (School of engineering, University of Applied Sciences, Western Switzerland). The original environment has been designed to sustain collaboration in domains characterized by predefined roles (guests, students, assistants, and educators), predefined types of shared assets (measurement data, equipment settings, experimentation protocols or analysis scripts) and predefined privileges and services. The CoPs ejournal is designed to let the users adapt features, structures and rules according to the tacit and evolving interaction schemes driving their community. This is achieved through the definition of a community protocol. The CoPs ejournal has been entirely developed as a collection of Web services using the .NET Framework. It is currently refined and validated for sustaining laboratory-oriented activities within two academic contexts: engineering education and joint research using scientific laboratory resources.

Web Based Catalogue of Online Experiments

Abstract: A knowledge base of online experiments was built. It is a kind of catalogue describing online experiments used for educational purposes. Metadata for describing this special kind of learning resources and analysis of experiments available in the catalogue (both virtual and remote) are presented in this paper. Examples of online lab experiments and exercises are developed by different European universities are also described.

Prototype of the web-based tool supporting argumentative collaboration towards learning

Abstract: This deliverable describes the prototype version of CoPe_it!, a web-based tool that supports argumentative collaboration towards learning. The prototype is in a demonstrable form, and can be used and tested through the web (http://copeit.cti.gr/). We present here the rationality behind its development, its generic features and functionalities, its technical specifications, and its deliberate limitations. We also provide a brief discussion on related approaches that validates our motivation and reveals interesting issues to be considered in the future. We conclude with a set of steps to be followed during the evolution of CoPe_it! in the next six months in the context of Palette.

Joint publication on adapting industrial simulations to obtain virtual experiments for learning

Abstract: The development of online experiments and especially virtual laboratories (i.e. interactive simulation of real equipments) is a complex and resource-consuming process. Their availability is however a prerequisite to any serious learning activities in sciences and engineering. The trend for reducing the implementation overhead for educators is to rely on professional simulation packages on top of which technology-enhanced learning layers are added. The first type of professional simulation packages used in education includes game development engines that provide suitable functionalities for effectively defining scenarios and rendering complex entities. The difficulty in this case is to develop the dynamical model of the scientific or technical objects to be simulated. The second type of professional simulation packages includes professional model libraries targeting at specific application domains. The difficulty here is related to the development of the interactive user interfaces (views). In the framework of the PROLEARN network of excellence, core and associated partners have developed and shared best practices for the development and the implementation of virtual laboratories relying on the EasyJava Simulations framework (http://www.um.es/fem/Ejs/), which is part of the Open Source Physics project. The EasyJava Simulations framework especially facilitates the design of virtual laboratories with highly interactive user interfaces (views). The present document presents a recent extension of this work that takes advantage of the freely available, object-oriented modelling language Modelica that strongly facilitates the reuse of industrial models in educational virtual laboratories, while keeping the benefits of the EasyJava Simulations. It corresponds to a state-of-the-art approach shared by PROLEARN partners. This document is the preprint of an article accepted for publication in the Mathematical and Computer Modelling of Dynamical Systems Journal (copyright Taylor & Francis) that is available online at http://journalsonline.tandf.co.uk/.