Marco Righero

Synchronization in Networks of Hindmarsh–Rose Neurons

Synchronization is deemed to play an important role in information processing in many neuronal systems. In this work, using a well known technique due to Pecora and Carroll, we investigate the existence of a synchronous state and the bifurcation diagram of a network of synaptically coupled neurons described by the Hindmarsh-Rose model. Through the analysis of the bifurcation diagram, the different dynamics of the possible synchronous states are evidenced. Furthermore, the influence of the topology on the synchronization properties of the network is shown through an example.

Evaluation of the Modeling of an EM Illumination on an Aircraft Cable Harness

This paper describes the approach developed in order to model the electromagnetic response of a cable bundle, part of the electrical wiring interconnection system of a real aircraft, submitted to an external electromagnetic excitation. The aim of this study is to highlight the main challenges in the synthetic modeling and validation of a fully real setup, from the electromagnetic compatibility point of view. Both conducted and radiated excitations have been considered in the electromagnetic global model. The solution is obtained through a cooperative simulation approach involving one 3-D full-wave solver and a multiconductor transmission line solver. The results are compared with measurements and specific tools, such as feature selective validation and integrated error against log frequency, are used to assess the adequacy of the results.

Sparse 2-D Array Placement for Arbitrary Pattern Mask and With Excitation Constraints: A Simple Deterministic Approach

We present a novel algorithm for the synthesis of planar (2-D) arrays subject to arbitrary pattern masks and excitation constraints (e.g., dynamic range). The algorithm is simple and deterministic, and considers the radiating element pattern. The procedure starts with a conventional constrained fixed-grid synthesis on a regular lattice, yielding a goal radiated field. Next, element locations are selected sequentially by maximizing projection on field difference to goal, while excitation amplitudes are computed using fixed-grid constrained synthesis for irregular lattices. The final result is the sparse layout and constrained excitation coefficients. The proposed method is validated against literature results; application examples are given for circular flat-top, isoflux and triangular flat-top shaped beam patterns, with constraints on excitation coefficients dynamic range, both for isotropic and patch-type element patterns.

Fast Antenna Testing With Reduced Near Field Sampling

This paper proposes an innovative functional testing methodology suitable for RF end-to-end antenna testing. Any measurement point requires mechanical movement and signal integration time to produce a sample; thus, the most radical way to reduce testing time is to reduce the number of required measured samples to a minimum. The presented approach exploits existing measurement capabilities, and allows a radical under-sampling via insertion of a-priori information by way of suitable use of advanced numerical modeling tools. The methodology can be used also with non-canonical grids, and when only a limited number of measured points is available. Experimental results are provided to show the potentials of the method.

Overview of the European project STRUCTURES

An overview of the European project STRUCTURES and its main challenges is given. Current and foreseen Intentional Electromagnetic Interference (IEMI) threats are classified according to their availability, their technical characteristics (such as bandwidth) and their portability. Critical infrastructures are identified and their most characteristic aspects are highlighted, from an electromagnetic point of view. These concepts are used to establish a set of reference threats to be investigated and possible techniques to handle simulations and measurements in this complex environment are explored, emphasizing the use of the topological approach.

Hierarchical Bases Preconditioner to Enhance Convergence of CFIE With Multiscale Meshes

A hierarchical quasi-Helmholtz decomposition, originally developed to address the dense-discretization breakdowns for the electric field integral equation, is applied together with an algebraic preconditioner to improve the convergence of the combined field integral equation in multiscale problems. The effectiveness of the proposed method is studied first on some simple examples; next, tests on real-life cases up to several hundreds of wavelengths show its good performance.

Master Stability Function for networks of Chua's circuits with static and dynamic couplings

An efficient tool to study synchronization of periodic oscillations in networks of coupled nonlinear oscillators, given by the joint application of the Master Stability Function and the Harmonic Balance, is applied to the to study of synchronization in networks of Chuas circuits coupled with resistors and capacitors.

The european project STRUCTURES: Challenges and results

The project STRUCTURES, funded by the European Union, started in July 2012 to study problems related to the emerging threats of electromagnetic attacks to critical infrastructures. Partners of the team have worked to list possible threats, identify the main characteristics of the critical infrastructures our way of living depends on, test current protection strategies with different simulation and measurement techniques, and condensate the results in guidelines accessible to an audience wider than the one of people working in the field. Here, we summarize the challenges, the solutions, and the results of almost three years of work.

Parametric interpolation using physics-based basis functions

An interpolation procedure to approximate the electromagnetic responses of structures for different values of some parameters describing the structures geometry is presented. Basis functions are obtained from known families (e.g. polynomials or trigonometric polynomials) and from a post-process of some actual responses of the system. The fitting, in the least squares sense, can be handled efficiently leveraging on the Kronecker form of the resulting linear system.

Frequency interpolation in the method of moments using the Discrete Empirical Interpolation Method

We present some preliminary results on the construction of a Reduced Order Model to simulate the electromagnetic response of a structure at different frequencies with Surface Integral Equations. The Discrete Empirical Interpolation Method, introduced for the simulation of nonlinear differential equations, is used in this context to accelerate the construction of the Reduced Order Model.