Dr Geo II: Adding Interactivity Planes in Interactive Dynamic Geometry

International audienceInteractive geometry environments support the creation and exploitation of interactive geometric sketches. However, such environments are often driven in a rigid manner, following a well specified construction path. This rigidity is not always compatible with: i. the internal cognitive representation of the learner about the geometric domain and ii. the way a geometric sketch is used in a paper-pen environment. This rigidity is therefore a source of internal tension for the learner and it can reduce the pedagogical added value of the interactive geometry environments. We think additional interactive planes to manipulate a geometric sketch differently can help the learner. We have developed DR. GEO II, an interactive geometry framework that is able to receive additional interactive planes such as a free sketching and a command-based one. We have experimented it in a junior high school class and we report here our first results

De l'importance des plans d'interaction dans la géométrie interactive

International audienceInteractive geometry environments support creation and exploitation of geometric sketches. However, such environments are often driven in a rigid manner, following a well specified construction path. This rigidity is not always compatible with the internal cognitive representation of the learner about the geometric domain. This rigidity is therefore a source of internal tension for the learner and it can reduce the pedagogical added value of these environments. We think addi- tional interactive planes to manipulate a geometric sketch differently can help the learner. We have developed an interactive geometry framework that is able to receive additional interactive planes such as a free sketching and a command-based one. We have experimented it in a junior high school class and we report here our results.Les environnements de géométrie interactive permettent créations et explorations de figures géométriques. Ceux-ci imposent cependant à l'apprenant un formalisme fort lors de la construction d'une figure. Cette rigidité n'est pas toujours compatible avec la représentation cognitive de l'ap- prenant du domaine d'apprentissage. Elle est donc source de tensions internes chez celui-ci et peut réduire la portée pédagogique de ces environnements. Nous pensons que des plans d'interaction supplémentaires pour manipuler différemment une même figure géométrique peuvent aider l'appre- nant. Nous avons ainsi développé un framework de géométrie interactive permettant l'ajout de tels plans puis nous avons expérimenté son utilisation dans une classe de 3e

Guidage macroscopique de l'apprentissage

National audienceLes EIAH sont souvent spécialisés dans un domaine bien précis. Cela leur permet d'of- frir des modélisations fines du domaine et de l'apprenant. L'analyse alors produite à partir des traces est didactiquement très fine et spécifique au domaine en question. Elle permet de guider l'apprenant en cas de difficulté et de lui proposer des activités de soutien. Cependant cette ana- lyse est étroitement liée aux domaines didactiques, et différente d'un domaine à un autre. Face à la diversité des domaines enseignés, comment proposer un modèle tenant compte de cette multitude et permettant une analyse de l'activité de l'élève et son guidage ? Nous proposons une analyse de l'activité de l'élève hors du champ didactique pour un guidage que nous nommons macroscopique, par opposition à une analyse didactique fine. Le guidage proposé est générique mais paramétré par un réseau notionnel afin d'être transposable à diffé- rents domaines d'enseignement. Notre approche s'appuie sur les réseaux notionnels, les étayages pédagogiques, les traces d'ob- jets et l'inférence sur celles-ci. Leur utilisation conjointe permet la description du domaine, la modélisation de l'apprenant et son pilotage par l'EIAH. Nous présentons cette approche dans iSTOA.net

iSTOA: Artefacts for mathematical interactive learning exercises

International audienceIn primary schools, mathematics teachers use support tools to introduce new concepts. The objective of these tools is to reinforce a mental representation of the newly introduced concept. Tools can be physical objects or paper-pen based. We call these tools artefacts. In computer assisted environments, such artefacts are not always clearly present, those environments focus on the nature of the exercises (drills, quiz). To realise environments in closer relation to classroom teaching, we propose to analyse and categorise such artefacts: we used pedagogical literature and we extracted artefacts used in teaching multiplication. We present our infrastructure and a list of artefacts in the multiplication realm

Microstructured air-silica fibres: Recent developments in modelling, manufacturing and experiment

37 pagesInternational audienceThe main modelling methods devoted to microstrutured air-silica optical fibres (MOFs) are presented and discussed. Then, the specific propagation properties of MOFs are studied in detail. Characteristics measured on fibres manufactured in our laboratory or reported in the literature are analysed. A large number of potential and demonstrated applications are presented and the obtained performances are discussed. A particular attention is given to hollow- core photonic bandgap fibres and their applications

Dr Geo II: Adding Interactivity Planes in Interactive Dynamic Geometry

International audienceInteractive geometry environments support the creation and exploitation of interactive geometric sketches. However, such environments are often driven in a rigid manner, following a well specified construction path. This rigidity is not always compatible with: i. the internal cognitive representation of the learner about the geometric domain and ii. the way a geometric sketch is used in a paper-pen environment. This rigidity is therefore a source of internal tension for the learner and it can reduce the pedagogical added value of the interactive geometry environments. We think additional interactive planes to manipulate a geometric sketch differently can help the learner. We have developed DR. GEO II, an interactive geometry framework that is able to receive additional interactive planes such as a free sketching and a command-based one. We have experimented it in a junior high school class and we report here our first results

Spy-Game on graphs

International audienceWe define and study the following two-player game on a graph G. Let k ∈ N *. A set of k guards is occupying some vertices of G while one spy is standing at some node. At each turn, first the spy may move along at most s edges, where s ∈ N * is his speed. Then, each guard may move along one edge. The spy and the guards may occupy same vertices. The spy has to escape the surveillance of the guards, i.e., must reach a vertex at distance more than d ∈ N (a predefined distance) from every guard. Can the spy win against k guards? Similarly, what is the minimum distance d such that k guards may ensure that at least one of them remains at distance at most d from the spy? This game generalizes two well-studied games: Cops and robber games (when s = 1) and Eternal Dominating Set (when s is unbounded). We consider the computational complexity of the problem, showing that it is NP-hard and that it is PSPACE-hard in DAGs. Then, we establish tight tradeoffs between the number of guards and the required distance d when G is a path or a cycle. Our main result is that there exists > 0 such that Ω(n 1+) guards are required to win in any n × n grid

Towards More Predictive Nuclear Reaction Modelling

Nuclear reaction modelling relies on three main theoretical models connected together, namely the optical model, the pre-equilibrium model and the compound nucleus model. Each of these models makes use of various input data, which can either be directly obtained from experiment or from experimentally-based systematics, fine-tuned to reproduce data of interest, or deduced from more fundamental bases. For well measured nuclei, one usually adopts phenomenological approaches consisting in fine-tuning input parameters to fit at best important experimental measurements. However, when dealing with reactions on exotic targets far from the valley of stability, alternatives to risky input data extrapolation have to be considered. Thanks to the high computer power available nowadays, all the input data required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon–nucleon effective interaction. This concerns nuclear masses, optical model potential, total nuclear level densities, photon strength functions, as well as fission paths. Both the quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. Perspectives will also be drawn for the coming years on the improvement one can expect with respect to the quality of these ingredients or to the theoretical models using them.SCOPUS: cp.pinfo:eu-repo/semantics/publishe