Flatness-based pre-compensation of laser diodes

International audienceA physical nonlinear dynamical model of a laser diode is considered. We propose a feed-forward control scheme based on differential flatness for the design of input-current modulations to compensate diode distortions. The goal is to transform without distortion a radio-frequency current modulation into a light modulation leaving the laser-diode and entering an optic fiber. We prove that standard physical dynamical models based on electron and photons balance are flat systems when the current is considered as control input, the flat output being the photon number (proportional to the light power). We prove that input-current is an affine map of the flat output, its logarithm and their time-derivatives up to order two. When the flat output is an almost harmonic signal with slowly varying amplitude and phase, these derivatives admit precise analytic approximations. It is then possible to design simple analogue electronic circuits to approximate the nonlinear computations required by our flatness-based inversion scheme. Simulations with the parameters of a commercial diode illustrate the practical interest of this pre-compensation scheme and its robustness versus modelling and analogue implementation errors

Computer-Assisted Generation of Patterns and Virtual Reality Techniques for Fashion Design

We present a methodology for the design of aesthetic patterns and their visualization on virtual clothes. Generated patterns are directly mapped on the dress of a virtual mannequin. Furthermore, patterns sets may be interactively mapped on the virtual dress using a specific 3D interaction technique called Back-and-Forth. Pattern generation involves different mathematical approaches such as iterated function systems (IFS) and nonlinear trajectory models. Both model parameters and color space exploration is performed through a simple user interface. This work contributes to promote both computer assistance in the context of mass customization for fashion design

3rd US-European Competition and Workshop on Micro Air Vehicle Systems (MAV07) European Micro Air Vehicle Conference and Flight Competition B-UAV tracking control integrating planned yaw and longitudinal/lateral inputs

In this study the tracking controller solution for the cartesian position and orientation (yaw) of the IBISC Bidirectional-Unmanned Arial Vehicle (B-UAV) is addressed in the cartesian coordinates. With respect to velocities based control, the cartesian accelerationbased model involves some difficulties in the conception of the tracking controller. Controlling the vehicle velocities (typical example from mobile robots) leads to a stabilizing/tracking of vehicle's positions. However, the problem is not straightforward when one considers acceleration-based motion. The aim of this work was to steer the B-UAV using the yaw attitude and two inclined rotor forces. The tracking control problem considers the dynamic model in accelerations and integrates some kinematic transformations. In neighborhood of the reference path, the transformed model in errors is linearized. Hence, the tracking results are local of nature but lead to a satisfactory simulation tracking tests. The planned yaw and longitudinal/lateral inputs are also considered in the tracking control design

Le tourisme saharien au sud-est tunisien, menace ou vecteur de développement durable des zones marginales

International audienc

Quelle alternative pour le développement des zones défavorisées en Tunisie ?

National audienceSouthern Tunisian regions benefited from several projects and programs of agricultural development demonstrating the determination of authorities to develop these discriminated regions. These projects are set up in the framework of the integrated rural development programme that aims at giving an impulse to the economic activity in the region and at managing its resources in a sustainable manner. Despite these actions, several dry regions are still isolated even though they are characterized by a very important wealth that can be enhanced. The innovation and the enhancement of this local wealth seem an interesting and essential solution for the development of these difficult areas. The region of Béni Khédache, in the South-East, is actually an example of these discriminated regions, confronted with several difficulties to follow the development pace but characterized by a very rich local wealth. This work aims at showing that the enhancement of the local heritage by local stakeholders can promote the sustainable development of these areas, from en economic, social and even environmental point of view. This local enhancement can be seen as an alternative for the development of this region.Le Sud est de la Tunisie a bénéficié de plusieurs projets et programmes de développement agricole qui montrent la détermination des pouvoirs publics à développer ces régions défavorisées. Ces projets font partie du programme de développement rural intégré qui vise à donner une impulsion à l'activité économique dans la région et à gérer ses ressources de manière durable. Malgré ces actions, plusieurs régions arides sont toujours enclavées même si elles peuvent être caractérisées par d'importantes richesses à mettre en valeur. La région de Béni Khédache du sud est tunisien en est un exemple. Cet article essaie de montrer que la valorisation du patrimoine local par les acteurs locaux constitue en elle-même un moteur pour le développement local durable de la zone aussi bien du point de vue économique que social et environnemental. Une telle valorisation devient une alternative pour le développement de cette région

Le tourisme saharien au sud-est tunisien, menace ou vecteur de développement durable des zones marginales

International audienc

Southern Tunisia patrimony: to restore properly and develop durably, vector of local development

National audienceLe développement du patrimoine architectural peut avoir des conséquences économiques étendues. Les travaux de conservation et de restauration des ksours, utilisant des technologies traditionnelles et agricoles peuvent mobiliser à la fois une main d'oeuvre spécialisée dans les travaux publics et l'artisanat. Les ksours, une fois restaurés et réhabilités, génèrent à leur tour de l'emploi dans le cadre de leur fonctionnement, leur maintenance et l'animation indirecte des ressources patrimoniales. Le tourisme culturel, même s'il n'en est pas le seul élément, peut contribuer à une nouvelle dynamique du développement durable. Les deux volets du schéma concernent d'une part une législation adéquate en vue de la classification des monuments historiques existants ainsi que leur plan de sauvegarde et d'autre part une politique de développement du patrimoine culturel - inclus dans le développement touristique sans toutefois le dénaturer et sans perdre sa valeur architecturale originelle. Le développement durable doit être une réponse transversale aux problèmes économiques, sociaux et écologiques