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  • Publication . Conference object . Part of book or chapter of book . 2002
    Open Access English
    Authors: 
    Giovanni Santin; D Strul; D. Lazaro; Luc Simon; M. Krieguer; M. Vieira Martins; Vincent Breton; C. Morel;
    Publisher: HAL CCSD
    Country: France
    Project: SNSF | Design and construction o... (63870)

    GATE, the Geant4 Application for Tomographic Emission, is a simulation platform developed for PET and SPECT. It combines a powerful simulation core (the Geant4 toolkit) and a large range of developments dedicated to nuclear medicine. In particular, it models the passing of time during real acquisitions, allowing to handle dynamic systems such as decaying source distributions or moving detectors. We present several series of results that illustrate the possibilities of this new platform. The simulation of decaying sources is illustrated on a dual-isotope acquisition with multiple time-frames. Count rate curves taking into account random coincidences and dead-time are shown for a dual-crystal set-up and for a small-animal PET scanner configuration. Simulated resolution curves and reconstructed images are shown for rotating PET scanners. Lastly, we present comparisons of simulated point-spread functions and spectra with experimental results obtained from a small-animal gamma camera prototype.

  • Publication . Part of book or chapter of book . 2016
    Open Access English
    Authors: 
    Sonia Mandin; Marina De Simone; Sophie Soury-Lavergne;
    Publisher: HAL CCSD
    Countries: Switzerland, France

    International audience; We study how elementary school pupils give sense to the moves of a mobile robot in a mathematical game. The game consists in choosing 3 numbers out of 6, whose sum is a given target number. The robot moves on a game board have been implemented to provide pupils with a tangible feedback about their answer. We have studied strategies of pupils to solve the problem and their evolution. Our methodology included interviews, aloud verbalization and video observations of 28 pupils in grade 1 and 2 while they are playing. The pursuit of a mastery goal encourages a trial and error strategy for only some of the pupils. We conclude that some aspects of the moves of the robot, like its position, are perceived as a form of help and not as a threat, even if they are only partially understood.

  • Open Access English
    Authors: 
    Loïc Riom;
    Publisher: HAL CCSD
    Countries: Switzerland, France

    International audience; Globalization through individualization together with an increase of translocal relations has opened up new ways of identification. Music as a set of symbolic elements enables this identification process. Indie rock as a globalized musical genre is a fruitful field that gives insight into understanding how individuals adopt and adapt a musical style. The aim of this research is to describe how indie rock bands are situated in Switzerland within the indie rock genre, and how they get in contact and identify with it. This research is based on 15 individual interviews conducted with members of six different Swiss indie bands. The results show that these bands uphold translocal identification with the international musical genre through, among others, the generalized use of English as the language of indie rock. However, since only few of them have connections abroad, this translocal identification is mainly mediated through the consumption of both live and recorded music from international artists. Due to this peripheral position, these bands are unable to play a significant role within the indie rock scene. Their music is, so to say, internationally inspired but locally produced. In this context, they are still very dependent on their geographical environment considered as a space of experience and resource. Yet, local identity does not seem to be claimed neither is the feeling of belonging to a local scene. This research shows that indie rock has to be understood through the lense of a rhizomic phenomenon, which is being constantly adapted by individuals through a variety of mediators. Moreover it challenges the idea of a local scene by showing how it is socially constructed.

  • Publication . Part of book or chapter of book . Other literature type . 2010
    Closed Access English
    Authors: 
    Géraldine Masson; Luc Neuville; Carine Bughin; Aude Fayol; Jieping Zhu;
    Publisher: HAL CCSD
    Countries: France, Switzerland

    How to access efficiently the macrocyclic structure remained to be a challenging synthetic topic. Although many elegant approaches/reactions have been developed, construction of diverse collection of macrocycles is still elusive. This chapter summarized the recently emerged research area dealing with multicomponent synthesis of macrocycles, with particular emphasis on the approach named “multiple multicomponent reaction using two bifunctional building blocks”.

  • Publication . Part of book or chapter of book . Article . 2005
    Open Access English
    Authors: 
    Pierre de la Harpe; Claude Pache;
    Publisher: HAL CCSD
    Country: Switzerland

    Cubature formulas and geometrical designs are described in terms of reproducing kernels for Hilbert spaces of functions on the one hand, and Markov operators associated to orthogonal group representations on the other hand. In this way, several known results for spheres in Euclidean spaces, involving cubature formulas for polynomial functions and spherical designs, are shown to generalize to large classes of finite measure spaces $(\Omega,\sigma)$ and appropriate spaces of functions inside $L^2(\Omega,\sigma)$. The last section points out how spherical designs are related to a class of reflection groups which are (in general dense) subgroups of orthogonal groups.

  • Publication . Part of book or chapter of book . Conference object . 2017
    Open Access English
    Authors: 
    Michał Maciejewski; Joschka Bischoff; Sebastian Hörl; Kai Nagel;
    Publisher: HAL CCSD
    Countries: France, Germany

    International audience; Since modern transport services are becoming more flexible, demand-responsive, and energy/cost efficient, there is a growing demand for large-scale microscopic simulation platforms in order to test sophisticated routing algorithms. Such platforms have to simulate in detail, not only the dynamically changing demand and supply of the relevant service, but also traffic flow and other relevant transport services. This paper presents the DVRP extension to the open-source MATSim simulator. The extension is designed to be highly general and customizable to simulate a wide range of dynamic rich vehicle routing problems. The extension allows plugging in of various algorithms that are responsible for continuous re-optimisation of routes in response to changes in the system. The DVRP extension has been used in many research and commercial projects dealing with simulation of electric and autonomous taxis, demand-responsive transport, personal rapid transport, free-floating car sharing and parking search.

  • Publication . Other literature type . 2006
    Open Access English
    Authors: 
    Dillenbourg, P.; Bétrancourt, M.;
    Publisher: HAL CCSD
    Country: Switzerland

    Does collaboration increase or decrease cognitive load during learning? On one hand, collaboration enables some degree of division of labour that may reduce cognitive load. On the other hand since interacting, expressing thoughts, monitoring another's understanding, grounding, etc., are mechanisms inducing some extraneous cognitive load, they may create cognitive overload and impede learning mechanisms. However this additional load may explain why collaboration sometimes leads to knowledge construction. This trade-off between productive versus counter-productive load is not specific to collaborative learning. It is also present in individual learning, namely questioning guided-discovery learning methods. This contribution explores the concept of cognitive load in collaborative situations. We raise more question than provide answers. What constitutes collaboration load, i.e. which mechanisms triggered during collaborative learning more often than during individual learning, contribute to increase cognitive load? In collaborative learning software, which interface features and tool functionalities increase or decrease the different costs factors (verbalization, grounding, modelling...)? We explore these questions and illustrate our arguments with three studies on computer-supported collaborative problem solving. We also consider how the collaboration load may be tuned through the design of computer-supported collaborative learning environments.

  • Publication . Part of book or chapter of book . 2018
    English
    Authors: 
    Philippe Delaporte; Anne-Patricia Alloncle; Thomas Lippert;
    Publisher: HAL CCSD
    Country: France

    International audience

  • Publication . Part of book or chapter of book . Book . 2003
    Open Access English
    Authors: 
    Leonardo Vanneschi; Marco Tomassini; Manuel Clergue; Philippe Collard;
    Publisher: HAL CCSD
    Country: France

    International audience; This paper presents an original study of fitness distance correlation as a measure of problem difficulty in genetic programming. A new definition of distance, called structural distance, is used and suitable mutation operators for the program space are defined. The difficulty is studied for a number of problems, including, for the first time in GP, multimodal ones, both for the new hand-tailored mutation operators and standard crossover. Results are in agreement with empirical observations, thus confirming that fitness distance correlation can be considered a reasonable index of difficulty for genetic programming, at least for the set of problems studied here.

  • Publication . Other literature type . Part of book or chapter of book . Preprint . Article . 2007
    Open Access English
    Authors: 
    Montanari, Andrea; Urbanke, Rudiger;
    Publisher: HAL CCSD
    Countries: France, Switzerland
    Project: SNSF | NCCR MICS: Mobile Informa... (67322)

    These are the notes for a set of lectures delivered by the two authors at the Les Houches Summer School on `Complex Systems' in July 2006. They provide an introduction to the basic concepts in modern (probabilistic) coding theory, highlighting connections with statistical mechanics. We also stress common concepts with other disciplines dealing with similar problems that can be generically referred to as `large graphical models'. While most of the lectures are devoted to the classical channel coding problem over simple memoryless channels, we present a discussion of more complex channel models. We conclude with an overview of the main open challenges in the field. Lectures at Les Houches Summer School on `Complex Systems', July 2006, 44 pages, 25 ps figures

search
Include:
961 Research products, page 1 of 97
  • Publication . Conference object . Part of book or chapter of book . 2002
    Open Access English
    Authors: 
    Giovanni Santin; D Strul; D. Lazaro; Luc Simon; M. Krieguer; M. Vieira Martins; Vincent Breton; C. Morel;
    Publisher: HAL CCSD
    Country: France
    Project: SNSF | Design and construction o... (63870)

    GATE, the Geant4 Application for Tomographic Emission, is a simulation platform developed for PET and SPECT. It combines a powerful simulation core (the Geant4 toolkit) and a large range of developments dedicated to nuclear medicine. In particular, it models the passing of time during real acquisitions, allowing to handle dynamic systems such as decaying source distributions or moving detectors. We present several series of results that illustrate the possibilities of this new platform. The simulation of decaying sources is illustrated on a dual-isotope acquisition with multiple time-frames. Count rate curves taking into account random coincidences and dead-time are shown for a dual-crystal set-up and for a small-animal PET scanner configuration. Simulated resolution curves and reconstructed images are shown for rotating PET scanners. Lastly, we present comparisons of simulated point-spread functions and spectra with experimental results obtained from a small-animal gamma camera prototype.

  • Publication . Part of book or chapter of book . 2016
    Open Access English
    Authors: 
    Sonia Mandin; Marina De Simone; Sophie Soury-Lavergne;
    Publisher: HAL CCSD
    Countries: Switzerland, France

    International audience; We study how elementary school pupils give sense to the moves of a mobile robot in a mathematical game. The game consists in choosing 3 numbers out of 6, whose sum is a given target number. The robot moves on a game board have been implemented to provide pupils with a tangible feedback about their answer. We have studied strategies of pupils to solve the problem and their evolution. Our methodology included interviews, aloud verbalization and video observations of 28 pupils in grade 1 and 2 while they are playing. The pursuit of a mastery goal encourages a trial and error strategy for only some of the pupils. We conclude that some aspects of the moves of the robot, like its position, are perceived as a form of help and not as a threat, even if they are only partially understood.

  • Open Access English
    Authors: 
    Loïc Riom;
    Publisher: HAL CCSD
    Countries: Switzerland, France

    International audience; Globalization through individualization together with an increase of translocal relations has opened up new ways of identification. Music as a set of symbolic elements enables this identification process. Indie rock as a globalized musical genre is a fruitful field that gives insight into understanding how individuals adopt and adapt a musical style. The aim of this research is to describe how indie rock bands are situated in Switzerland within the indie rock genre, and how they get in contact and identify with it. This research is based on 15 individual interviews conducted with members of six different Swiss indie bands. The results show that these bands uphold translocal identification with the international musical genre through, among others, the generalized use of English as the language of indie rock. However, since only few of them have connections abroad, this translocal identification is mainly mediated through the consumption of both live and recorded music from international artists. Due to this peripheral position, these bands are unable to play a significant role within the indie rock scene. Their music is, so to say, internationally inspired but locally produced. In this context, they are still very dependent on their geographical environment considered as a space of experience and resource. Yet, local identity does not seem to be claimed neither is the feeling of belonging to a local scene. This research shows that indie rock has to be understood through the lense of a rhizomic phenomenon, which is being constantly adapted by individuals through a variety of mediators. Moreover it challenges the idea of a local scene by showing how it is socially constructed.

  • Publication . Part of book or chapter of book . Other literature type . 2010
    Closed Access English
    Authors: 
    Géraldine Masson; Luc Neuville; Carine Bughin; Aude Fayol; Jieping Zhu;
    Publisher: HAL CCSD
    Countries: France, Switzerland

    How to access efficiently the macrocyclic structure remained to be a challenging synthetic topic. Although many elegant approaches/reactions have been developed, construction of diverse collection of macrocycles is still elusive. This chapter summarized the recently emerged research area dealing with multicomponent synthesis of macrocycles, with particular emphasis on the approach named “multiple multicomponent reaction using two bifunctional building blocks”.

  • Publication . Part of book or chapter of book . Article . 2005
    Open Access English
    Authors: 
    Pierre de la Harpe; Claude Pache;
    Publisher: HAL CCSD
    Country: Switzerland

    Cubature formulas and geometrical designs are described in terms of reproducing kernels for Hilbert spaces of functions on the one hand, and Markov operators associated to orthogonal group representations on the other hand. In this way, several known results for spheres in Euclidean spaces, involving cubature formulas for polynomial functions and spherical designs, are shown to generalize to large classes of finite measure spaces $(\Omega,\sigma)$ and appropriate spaces of functions inside $L^2(\Omega,\sigma)$. The last section points out how spherical designs are related to a class of reflection groups which are (in general dense) subgroups of orthogonal groups.

  • Publication . Part of book or chapter of book . Conference object . 2017
    Open Access English
    Authors: 
    Michał Maciejewski; Joschka Bischoff; Sebastian Hörl; Kai Nagel;
    Publisher: HAL CCSD
    Countries: France, Germany

    International audience; Since modern transport services are becoming more flexible, demand-responsive, and energy/cost efficient, there is a growing demand for large-scale microscopic simulation platforms in order to test sophisticated routing algorithms. Such platforms have to simulate in detail, not only the dynamically changing demand and supply of the relevant service, but also traffic flow and other relevant transport services. This paper presents the DVRP extension to the open-source MATSim simulator. The extension is designed to be highly general and customizable to simulate a wide range of dynamic rich vehicle routing problems. The extension allows plugging in of various algorithms that are responsible for continuous re-optimisation of routes in response to changes in the system. The DVRP extension has been used in many research and commercial projects dealing with simulation of electric and autonomous taxis, demand-responsive transport, personal rapid transport, free-floating car sharing and parking search.

  • Publication . Other literature type . 2006
    Open Access English
    Authors: 
    Dillenbourg, P.; Bétrancourt, M.;
    Publisher: HAL CCSD
    Country: Switzerland

    Does collaboration increase or decrease cognitive load during learning? On one hand, collaboration enables some degree of division of labour that may reduce cognitive load. On the other hand since interacting, expressing thoughts, monitoring another's understanding, grounding, etc., are mechanisms inducing some extraneous cognitive load, they may create cognitive overload and impede learning mechanisms. However this additional load may explain why collaboration sometimes leads to knowledge construction. This trade-off between productive versus counter-productive load is not specific to collaborative learning. It is also present in individual learning, namely questioning guided-discovery learning methods. This contribution explores the concept of cognitive load in collaborative situations. We raise more question than provide answers. What constitutes collaboration load, i.e. which mechanisms triggered during collaborative learning more often than during individual learning, contribute to increase cognitive load? In collaborative learning software, which interface features and tool functionalities increase or decrease the different costs factors (verbalization, grounding, modelling...)? We explore these questions and illustrate our arguments with three studies on computer-supported collaborative problem solving. We also consider how the collaboration load may be tuned through the design of computer-supported collaborative learning environments.

  • Publication . Part of book or chapter of book . 2018
    English
    Authors: 
    Philippe Delaporte; Anne-Patricia Alloncle; Thomas Lippert;
    Publisher: HAL CCSD
    Country: France

    International audience

  • Publication . Part of book or chapter of book . Book . 2003
    Open Access English
    Authors: 
    Leonardo Vanneschi; Marco Tomassini; Manuel Clergue; Philippe Collard;
    Publisher: HAL CCSD
    Country: France

    International audience; This paper presents an original study of fitness distance correlation as a measure of problem difficulty in genetic programming. A new definition of distance, called structural distance, is used and suitable mutation operators for the program space are defined. The difficulty is studied for a number of problems, including, for the first time in GP, multimodal ones, both for the new hand-tailored mutation operators and standard crossover. Results are in agreement with empirical observations, thus confirming that fitness distance correlation can be considered a reasonable index of difficulty for genetic programming, at least for the set of problems studied here.

  • Publication . Other literature type . Part of book or chapter of book . Preprint . Article . 2007
    Open Access English
    Authors: 
    Montanari, Andrea; Urbanke, Rudiger;
    Publisher: HAL CCSD
    Countries: France, Switzerland
    Project: SNSF | NCCR MICS: Mobile Informa... (67322)

    These are the notes for a set of lectures delivered by the two authors at the Les Houches Summer School on `Complex Systems' in July 2006. They provide an introduction to the basic concepts in modern (probabilistic) coding theory, highlighting connections with statistical mechanics. We also stress common concepts with other disciplines dealing with similar problems that can be generically referred to as `large graphical models'. While most of the lectures are devoted to the classical channel coding problem over simple memoryless channels, we present a discussion of more complex channel models. We conclude with an overview of the main open challenges in the field. Lectures at Les Houches Summer School on `Complex Systems', July 2006, 44 pages, 25 ps figures

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