Showing papers by "Denis Gillet published in 2008"

Turning Web 2.0 Social Software into Versatile Collaborative Learning Solutions

Abstract: In the framework of the European Integrated Project PALETTE, the Ecole Polytechnique Federale de Lausanne (EPFL) is developing the eLogbook Web 2.0 social software. The purpose of eLogbook is to support tacit and explicit knowledge management in communities of practice. It can be customized by the users to serve as an asset management system, as a task management system or as a discussion platform. In this paper, the innovative Computer-Human Interaction features of eLogbook are introduced and its deployment scenario to support collaborative laboratory activities in engineering education is described. The main idea is to sustain interaction for learning purpose within self-organized teams that integrate -on a seamless level- both human actors (students, teaching assistants) and non-human actors such as laboratory equipments or software agents.

A systematic two-layer approach to develop Web-based experimentation environments for control engineering education

Abstract: This paper introduces the systematic approach currently used by the Department of Computer Science and Automatic Control of the Spanish University of Distance Learning (UNED) to develop Web-based laboratories for distance learning of topics with high technical contents such as control engineering. This approach differentiates two layers in the construction of web- based laboratories: the experimentation layer and the e-learning layer. For the experimentation layer, LabVIEW and data acquisition boards from National Instruments are used to create the server-side applications and Easy Java Simulations for the client-side interfaces. For the e-learning layer, the eMersion environment is used to support the required flexible educational scheme. This paper describes the programming techniques implemented and the design considerations that justify these particular choices. As an llustrative case-study, an example of development of a web-based application is discussed, in which an electrical drive servo-motor is introduced as a convenient setup to practice with motion control applications. Other significant examples of web-based experiments developed by the authors are also reported.

From online experiments to smart devices

Abstract: Online experiments have been available for more than a decade. The integration of online experiments into collaborative environments is more recent. The wealth of client applications/environments, the versatility of possible interaction protocols/technologies and the needs for more autonomous actions impel the evolution of online experiments to the smart device concept. This paper reviews the evolution of an electrical drive experiment and presents the requirements for turning online experiments into smart devices.

Real-time compensation of hysteresis in a piezoelectric-stack actuator tracking a stochastic reference

Abstract: This paper presents a convenient way to invert the classical Preisach model to compensate the hysteresis of a piezoelectric stack actuator in real-time. The advantage of the proposed method lies the possibility to track a stochastic signal and compensate the hysteresis in real-time. Experimental results show a reduction of the RMS tracking error by 67% to 90% by using the compensation algorithm designed.

The ESPRI project: astrometric exoplanet search with PRIMA

Abstract: PRIMA, the instrument for Phase-Referenced Imaging and Micro-arcsecond Astrometry at the VLTI, is currently being developed at ESO. PRIMA will implement the dual-feed capability, at first for two UTs or ATs, to enable simultaneous interferometric observations of two objects that are separated by up to 1 arcmin. PRIMA is designed to perform narrow-angle astrometry in K-band with two ATs as well as phase-referenced aperture synthesis imaging with instruments like Amber and Midi. In order to speed up the full implementation of the 10 microarcsec astrometric capability of the VLTI and to carry out a large astrometric planet search program, a consortium lead by the Observatoire de Geneve, Max Planck Institute for Astronomy, and Landessternwarte Heidelberg, has built Differential Delay Lines for PRIMA and is developing the astrometric observation preparation and data reduction software. When the facility becomes fully operational in 2009, we will use PRIMA to carry out a systematic astrometric Exoplanet Search program, called ESPRI. In this paper, we describe the narrow-angle astrometry measurement principle, give an overview of the ongoing hardand software developments, and outline our anticipated astrometric exoplanet search program.

The ESPRI Project: differential delay lines for PRIMA

Abstract: ESPRI is a project which aims at searching for and characterizing extra-solar planets by dual-beam astrometry with PRIMA@VLTI. Differential Delay Lines (DDL) are fundamental for achieving the micro-ar cseconds accuracy required by the scientific objective. Our Consortium, consisting of the Geneva Observatory, the Max-Planck Institut for Astronomy Heidelberg, and the Landessternwarte Heidelberg, in collaboration with ESO, has built and tested these DDLs successfully and will install them in summer 2008 at the VLTI. These DDLs consist of high quality cat’s eyes displaced on a parallel beam-mechanics and by means of a two-stage actuation with a precision of 5 nm over a stroke length of 70 mm. Over the full range, a bandwidth of about 400 Hz is achieved. The DDLs are operated in vacuum. We shall present, in this paper, their design and their exceptional performances. Keywords: Interferometry, near infrared, astrom etry, extrasolar planets, delay lines *Francesco.Pepe@obs.unige.ch

Social Software Modeling and Mashup based on Actors, Activities and Assets

Abstract: Despite the extreme diversity of Web applications, one can find similarities among them This paper proposes an answer to the question of knowing whether it is possible to conceptually represent different Web applications in a common manner such that they can generically be integrated in other Web applications The 3A model developed at EPFL in the framework of the European PALETTE project is used to generalize the visual and functional properties of Web applications A Web 20 personal learning environment based on the 3A model called eLogbook is used as a mashup container to integrate existing Web applications The mapping procedure is described and illustrated with the example of an instant messaging application, showing that mashup is possible with 3A model

Participatory Design for Awareness Features: Enhancing Interaction in Communities of Practice

Abstract: In the framework of the European Integrated Project PALETTE, the Ecole Polytechnique Federale de Lausanne (EPFL) and the University of Patras are developing mediation services. These services aim at sustaining collaboration, supporting tacit and explicit knowledge management and enhancing individual and organizational learning in communities of practice (CoPs). Defined by Dourish and Belloti as "an understanding of the activities of others, which provides a context for one's own activity", awareness is one of the most crucial needs expressed by communities of practice in the framework of the participatory design process implemented within the Palette project. Awareness of past and current actions in shared environments and over shared artifacts motivates participation and guides the members' decisions and course of actions. This paper describes the approach adopted by two Web-based collaboration support applications, namely eLogbook and CoPe_it!, for developing awareness services. CoPs needs, in terms of awareness, were identified through the participatory design approach. Then, a combination of relevant awareness types found in the literature was adopted in order to address the identified awareness requirements. The resulting awareness services implemented by Palette's mediation services (eLogbook and CoPe_it!) are presented. In particular, the kind of awareness information provided and its rendering means are described. For each tool, the available awareness functionality is related to the awareness type it contributes.

Dedicated controller design for a dual-stage opto-mechatronic system

Abstract: To improve the resolution of the very large telescope interferometer (VLTI) a two-stage mechanical system, a so called differential delay line (DDL), is developed jointly by the EPFL and the Observatory of Geneva. The system is designed to reach nanometer accuracy at high bandwidth over large displacements. The coarse stage features a permanent magnet (PM) stepper motor driving a lead screw connected to a double-parallelogram flexure with notch-hinges (blade) guiding system, and the fine stage features a stacked piezoelectric device, combine to one single measurable output. This paper compares different control approaches for the DDL with their respective advantages and disadvantages. The developed control methods are based on modern linear and nonlinear control theory. The performance of the control schemes is illustrated via simulation and measurement on the available prototype. The new developed methods are compared to the currently implemented decoupled SISO design which features a direct-coil controller for the coarse stage and a simple PID-controller for the fine one.

Social Software for Supporting Interaction in a Community of Practice Dedicated to e-Learning

Abstract: Keywords: social networking systems ; Web 2.0 Note: Prj_elogbook Reference LA-PRESENTATION-2008-015 URL: http://research.ihost.com/cscw08-socialnetworkinginorgs/ Record created on 2008-11-24, modified on 2016-08-08

Feed-oriented awareness services for e-logbook mobile users

Abstract: The e-logbook is a collaborative web-based environment deployed by the Swiss Federal Institute of Technology in Lausanne (EPFL). It consists of an activity-oriented space where a community of educators, teaching assistants and students can form groups, conduct activities and perform several actions over stored and shared assets. Moreover, the e-logbook offers awareness services to sustain collaboration and coordination among the community members. This paper presents adaptive feed-oriented services designed and implemented to deliver awareness to mobile users, taking into account their device limitations and their activity context.

Developing Interoperable Collaboration Services to Sustain Activities of Communities of Practice

Abstract: Communities of Practice (CoPs) have attracted the interest of professionals and researchers as successful environments for enhancing, developing and improving practices through collaboration between their members. More and more, CoPs are choosing virtual environments and services to support their activities. However, recent research has underlined the lack of adequate scaffolding in terms of technical support and appropriate use of technology for communication and collaboration. The paper argues in favour of a collaborative design methodology for the development of services based on new technologies, open-source or "open-source minded". Producing interoperable, evolutionary, flexible and truly collaborative services appears of major interest to sustain activities of distributed CoPs. The paper uses as a case study the description of collaboratively designed services addressing the needs of distributed CoPs within the European Project PALETTE. The example of PALETTE shows that in complex project situations, collaborative design sustained by Actor-Network Theory is a helpful framework to reach the goals of the project.