Ricerc@Sapienza

The editorial describe the content of the Special Issue on Emerging Technologies for Ubiquitous and Intelligent Infrastructures, including six papers: “Joint Atomic Norm based Estimation of Sparse Time Dispersive SIMO Channels with Common Support in Pilot Aided OFDM Systems,” “Performance Evaluation of Non-prefiltering vs.

The need to manage connectivity, when Internet access is granted indoor via Visible Light Communications, leads to acquire information about user position. This is useful for accessing the medium via space division multiplexing and/or giving rise to handover procedure or, more, providing access to location based contents, as for example, in large indoor environments as malls or museums. In this regard, we propose a localization mechanism that exploits the properties of metamerism so that the red, green, and blue components used by LEDs, provide the white light sensation to the human eye.

The applications of spaceborne GNSS reflectometry data over land are investigated in this work using the data collected by the UK TechDemoSat experimental mission. In order to quantify the sensitivity of the GNSS reflections to biomass and soil moisture from real data it is necessary to extract a quantity, like the surface reflectivity, as much as possible independent from the system parameters. At the same time, to understand the scattering mechanisms and potentialities and limitations of GNSS-R over land, an electromagnetic simulator has to be used and compared to the experimental data.

Fabry-Perot cavity antennas with polarization-reconfigurable omnidirectional conical beams are presented. The partially reflecting screen covering the antenna cavity is constituted by omnidirectional homogenized metasurfaces exhibiting rotationally invariant electromagnetic features, and specifically metal patterned screens are considered. The antenna operates on the first higher-order TMi and TEi leaky modes, whose phase and attenuation constants are properly equalized.

Network Function Virtualization is a new technology allowing for a elastic cloud and bandwidth resource allocation. The technology requires an orchestrator whose role is the service and resource orchestration. It receives service requests, each one characterized by a Service Function Chain, which is a set of service functions to be executed according to a given order. It implements an algorithm for deciding where both to allocate the cloud and bandwidth resources and to route the SFCs.

This paper deals with the adoption of Unmanned Aerial Vehicles (UAVs) as mobile Base Stations providing video streaming services within a cellular macro area. We devise a Q-learning based UAV flight planning algorithm aimed at improving the Quality of Experience (QoE) of video users. Specifically, the proposed algorithm, herein denoted as Q-SQUARE, leverages the well-established Q-learning algorithm by introducing a reward related to a key QoE metric that is the video segment delay.

Aim of the present study was to test and validate an ex vivo predictive model for the evaluation of the shrinkage occurring in hepatic tissue during a microwave thermal ablation procedure. Microwave ablation (N=134) was conducted with three different commercial devices on cubes of ex vivo liver (15-40\pm 2 mm side) embedded in agar phantoms. 50-60W was applied for 1-10 min duration. Pre-and post-ablation dimensions of the samples, as well as the extent of carbonization and coagulation were measured.

It has recently been shown that the relaxation time of a graphene sheet is the crucial parameter that governs the radiation performance in graphene THz antennas based on either plasmonic or nonplasmonic leaky waves. Moreover, the radiating properties of these devices have always been derived assuming an ideal dipole-like source, and no full-wave and experimental results on realistic feeders have been reported, yet. To this purpose, in this work we aim at bringing the designs of graphene-based Fabry-Perot cavity leaky-wave antennas (FPC-LWAs) towards an experimental stage.

The shielding effectiveness of a planar multilayered screen is computed in the time domain in the presence of near-field magnetic sources. The proposed numerical method involves the efficient evaluation of classical Sommerfeld integrals and the inverse-Fourier transform through double-exponential formulas. For sufficiently thin screens with highly-conductive properties, an analytical method, based on a modified Cagniard-de Hoop approach, is also presented to validate the results.

.