Portail HAL Ensta
Not a member yet
11080 research outputs found
Sort by
The linear sampling method for data generated by small random scatterers
No full textInternational audienc
Le programme MAP-IO et son volet GNSS pour l’observation de la vapeur d’eau sur les Océans Austral et Indien
No full textInternational audienc
Drones suicides, munitions rôdeuses, etc. : appui ou remplacement des capacités missiles ?
No full textInternational audienc
Propagation d'impulsions laser intenses dans l'air
No full textInternational audienceLa propagation d’impulsions laser intenses et très courtes dans l’air donne lieu à des effets spectaculaires. Nous décrivons dans cet article plusieurs expériences réalisées avec le laser teramobile et ses successeurs
Operation-based versioning as a foundation for live executable models
No full textInternational audienceLive modeling is the ability to edit an executable model at run-time, and to subsequently continue the execution instead of having to restart it. Few modeling frameworks support this feature. Much of the research concerning live modeling attempts to bring “liveness” to existing modeling languages and environments, which is a complex, and often ad hoc endeavor. We instead argue to build modeling environments on an operation-based versioning foundation, to not only record edit operations, but also execution steps on an explicit run-time model. This reduces the complexity of patching the run-time state with edit operations to a simple merge-operation, while getting powerful features such as collaborative editing and debugging “for free.
A model-based kinematic guidance method for control of underactuated autonomous underwater vehicles
No full textInternational audienceIn this work, a novel guidance principle for underactuated autonomous underwater vehicles is introduced. This new method relies on the kinematic coupling between non-actuated and actuated degrees of freedom. It uses a newly introduced matrix called the Handy Matrix denoted H. The method allows reassigning unused degrees of freedom of the task to useful non-actuated DOF. The algorithm and design rules leading to the construction of H are also provided. Two different solutions based on matrix H are compared on a standard seabed scanning task
Naïve Unsupervised Bioacoustics Signal Processing with Nonnegative Matrix Factorization
No full textNational audienc
The Human is Not in Space. Humankind is in Space
No full textInternational audienceA contribution to philosophical anthropology exploring the relationship between humanity and outer space by studying how different ways of imagining and defining the essence of the human stand up to the empirical and experiential realities of life aboard the ISS. The aim of the paper is to show that in the Anthropocene understood as a Post-Planetary Age we ought to neither treat our encounter space as necessarily entangled with a flight away from the planet, nor as a justification for returning to Earth, but rather include it as a critical location within the narrative of planetization which can contribute to helping us to understand more clearly where we are, and how our choices and actions might come to affect the future of planetary life
Compression-compression fatigue of quasi-isotropic laminates: Failure mechanisms and link between dissipative behavior and fatigue life
No full textInternational audienceFew studies have investigated the fatigue of composite laminates under cyclic compression loading. Moreover, the self-heating approach to rapidly predict fatigue life has rarely been applied to this type of material. The objective of this work is to study the fatigue of a quasi-isotropic laminate under compression-compression loadings and to assess the possibility of rapidly determining an endurance limit from a self-heating test. Compression-compression fatigue and self-heating tests were carried out on a carbon/epoxy quasi-isotropic laminate with a stress ratio of 10. Fatigue tests were conducted for lifetimes up to 108 cycles. The damage scenario is investigated by interrupting fatigue tests and conducting subsequent observations of the samples using scanning electron microscopy and X-ray micro-computed tomography. A methodology for analyzing self-heating tests is applied, which allows the determination of the mean volumetric intrinsic cyclic dissipation of the laminate from surface thermal measurements. A method using a viscoelastic constitutive law is proposed to estimate the endurance limit from the self-heating curve