Time Domain Inverse Scattering for a Buried Homogeneous Cylinder in a Slab Medium Using NU-SSGA

[[abstract]]A time-domain inverse scattering technique for reconstructing a buried homogeneous cylinder with arbitrary cross section in a slab medium is proposed. For the forward scattering, the FDTD method is employed to calculate the scattered E fields. Base on the scattering fields, these inverse scattering problems are transformed into optimization problems. The non-uniform steady state genetic algorithm (NU-SSGA) is applied to reconstruct the location shape and permittivity of the two-dimensional homogeneous dielectric cylinder. The NU-SSGA is a population-based optimization approach that aims to minimize the objective function between measurements and computer-simulated data. A set of representative numerical results is presented for demonstrating that the proposed approach is able to efficiently reconstruct the electromagnetic properties of homogeneous dielectric scatterer even when the initial guess is far away from the exact one. In addition, the effects of Gaussian noises on the image reconstruction are also investigated.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]電子

GPR applications across Engineering and Geosciences disciplines in Italy: a review

In this paper, a review of the main ground-penetrating radar (GPR) applications, technologies, and methodologies used in Italy is given. The discussion has been organized in accordance with the field of application, and the use of this technology has been contextualized with cultural and territorial peculiarities, as well as with social, economic, and infrastructure requirements, which make the Italian territory a comprehensive large-scale study case to analyze. First, an overview on the use of GPR worldwide compared to its usage in Italy over the history is provided. Subsequently, the state of the art about the main GPR activities in Italy is deepened and divided according to the field of application. Notwithstanding a slight delay in delivering recognized literature studies with respect to other forefront countries, it has been shown how the Italian contribution is now aligned with the highest world standards of research and innovation in the field of GPR. Finally, possible research perspectives on the usage of GPR in Italy are briefly discussed

Sistema modular de medição do movimento humano baseado em ROS e sensores inerciais

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Faculdade UnB Gama, 2019.O presente trabalho apresenta uma proposta de um sistema modular de medição do movimento humano baseado em ROS e sensores inerciais. O objetivo do projeto é projetar um protótipo de um sistema de medição dos ângulos da articulação do cotovelo utilizando duas IMUs, uma localizada no braço, próximo ao cotovelo e outra localizada no antebraço. O ROS facilita a interconexão entre as unidades de medição inercial possibilitando o acoplamento de múltiplas IMUs. O projeto final apresenta um sistema capaz de captar os ângulos da junta do braço através de dois MPU-6050 acoplados ao corpo que realizam a aquisição desses dados que são tratados e expostos como uma subtração das angulações do movimento de inclinação pitch e roll.The present work presents a proposal of a modular system of human movement measurement based on ROS and inertial sensors. The objective of the project is design a prototype of an elbow joint angle measurement system using two IMUs, one located in the arm, near the elbow and another located on the forearm. The ROS facilitates the interconnection between the inertial measurement units allowing the coupling of multiple IMUs. The final design features a system capable of capturing the arm joint angles through two MPU- 6050 coupled to the body that perform the acquisition of these data that are treated and exposed as a subtraction of the angles of pitch and roll tilt movement

Through-the-Wall Imaging and Multipath Exploitation

We consider the problem of using electromagnetic sensing to estimate targets in complex environments, such as when they are hidden behind walls and other opaque objects. The often unknown electromagnetic interactions between the target and the surrounding area, make the problem challenging. To improve our results, we exploit information in the multipath of the objects surrounding both the target and the sensors. First, we estimate building layouts by using the jump-diffusion algorithm and employing prior knowledge about typical building layouts. We also take advantage of a detailed physical model that captures the scattering by the inner walls and efficiently utilizes the frequency bandwidth. We then localize targets hidden behind reinforced concrete walls. The sensing signals reflected from the targets are significantly distorted and attenuated by the embedded metal bars. Using the surface formulation of the method of moments, we model the response of the reinforced walls, and incorporate their transmission coefficients into the beamforming method to achieve better estimation accuracy. In a related effort, we utilize the sparsity constraint to improve electromagnetic imaging of hidden conducting targets, assuming that a set of equivalent sources can be substituted for the targets. We derive a linear measurement model and employ l1 regularization to identify the equivalent sources in the vicinity of the target surfaces. The proposed inverse method reconstructs the target shape in one or two steps, using single-frequency data. Our results are experimentally verified. Finally, we exploit the multipath from sensor-array platforms to facilitate direction finding. This in contrast to the usual approach, which utilizes the scattering close to the targets. We analyze the effect of the multipath in a statistical signal processing framework, and compute the Cramer-Rao bound to obtain the system resolution. We conduct experiments on a simple array platform to support our theoretical approach