Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.
AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.
Compressive sensing (CS) is an alternative to Shannon/Nyquist sampling for acquisition of sparse or compressible signals that can be well approximated by just K < N elements from an N-dimensional basis. Instead of taking periodic samples, we measure inner ...
Institute of Electrical and Electronics Engineers2010
Joints are important mechanical and hydrological features of rock masses, and they can greatly affect wave propagation and attenuation across jointed rock masses. Joints often contain liquid, and the presence of liquid will change the mechanical behaviors ...
The dynamic control of the beamwidth of a partially reflective surface (PRS) antenna is reported for the first time. First, a design methodology is proposed by revisiting the PRS antenna theory from the perspective of its reconfigurable beamwidth operation ...
Institute of Electrical and Electronics Engineers2010
An equivalent viscoelastic medium model is proposed for rock mass with parallel joints. A concept of "virtual wave source (VWS)'' is proposed to take into account the wave reflections between the joints. The equivalent model can be effectively applied to a ...
A reflecting cell allowing the dynamic and independent control of the reflection phase of two perpendicular linearly-polarized waves is presented. This capability is useful for the implementation of dual-polarized beam-reconfigurable reflectarrays, as well ...
Institute of Electrical and Electronics Engineers2010
Different methods are presently available for the analysis of wave propagation across jointed rock masses with the consideration of multiple wave reflections between joints. These methods can be divided into two categories. One is based on the displacement ...
A one-dimensional acoustic negative refractive index metamaterial based on the transmission line approach is presented. This structure implements the dual transmission line concept extensively investigated in microwave engineering. It consists of an acoust ...
Within the last years, an increasing number of studies have been carried out in the field of acoustic metamaterials. These artificial composite materials aim at achieving new macroscopic properties, like negative refraction, that are not readily present in ...
In this paper we review simplified analytical expressions derived by Wait using the concept of attenuation function for the analysis of the propagation of lightning-radiated electromagnetic fields over a mixed propagation path (vertically stratified ground ...
Lossless transmission of a set of correlated sources over a deterministic relay network is considered for two traffic requirements. In distributed multicast, the set of sources are to be delivered to a set of destinations. The source exchange requires all ...
