1,721,139 research outputs found
A new non-iterative inversion method for Electrical Resistance Tomography
No full textIn this paper, the inverse problem of resistivity retrieval is addressed in the frame of electrical resistance tomography (ERT). The ERT data is a set of measurements of the dc resistances between pairs of electrodes in contact with the conductor under investigation. This paper is focused on a non-iterative inversion method based on the monotonicity, of the resistance matrix (and of its numerical approximations). The main features of the proposed inversion method are its low computational cost requiring the solution of O(n) direct problems, where n is the number of parameters used to represent the unknown resistivity, and its very simple numerical implementation
An integral formulation for the electromagnetic analysis of lossy conductors and dielectrics
No full text
A new non-iterative inversion method for Electrical Resistance Tomography
No full textIn this paper, the inverse problem of resistivity retrieval is addressed in the frame of electrical resistance tomography (ERT). The ERT data is a set of measurements of the dc resistances between pairs of electrodes in contact with the conductor under investigation. This paper is focused on a non-iterative inversion method based on the monotonicity, of the resistance matrix (and of its numerical approximations). The main features of the proposed inversion method are its low computational cost requiring the solution of O(n) direct problems, where n is the number of parameters used to represent the unknown resistivity, and its very simple numerical implementation
A Broadband Volume Integral Formulation Based on Edge-Elements for Full-Wave Analysis of Lossy Interconnects
No full textA new numerical fully three-dimensional (3-D) volume integral formulation for the electromagnetic analysis from static to microwave frequencies of penetrable materials (dielectric, eventually lossy, and conductors with finite conductivity) is here discussed. Its key feature is the introduction of a volumetric loop-star decomposition for treating piecewise homogeneous materials. The associated shape functions have been determined to decompose the volume current density in a solenoidal and a nonsolenoidal part, in analogy to the surface loop-star shape functions, used for modeling surface current densities on perfect electric conductors. The possibility of modeling volumetric ohmic and polarization current densities allows to compute in an accurate way the electromagnetic field in complex 3-D geometries, such as high speed interconnects, on a broad range of frequencies
Fast methods for quantitative eddy-current tomography of conductive materials
No full textIn this paper, we address the imaging of the spatial distribution of the resistivity of conductive materials by using data from eddy-current nondestructive testing. Specifically, the data consists of measurements of the impedance matrix at several frequencies acquired using. a coil array. The imaging method processes the second-order term (estimated from the measured data) of the power series expansion, with respect to frequency, of the impedance matrix. This term accounts for the resistive contribution to changes of the impedance matrix, due to the presence of anomalies in the conductor under test, occurring at relatively low frequencies. The operator mapping a given resistivity distribution inside the conductor into the second-order term satisfies a proper monotonicity property. The monotonicity makes it possible to apply a fast noniterative imaging method initially developed by the authors for elliptic problems such as electrical resistance tomography. Numerical examples show the main features of the proposed method, and demonstrate the possibility of real-time imaging
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