Optimization of Reconfigurable Intelligent Surfaces with Electromagnetic Field Exposure Constraints

This work tackles the problem of maximizing the achievable rate in a reconfigurable intelligent surface (RIS)-assisted communication link, by enforcing conventional maximum power constraints and additional constraints on the maximum exposure to electromagnetic radiations of the end-users. The RIS phase shift matrix, the transmit beamforming filter, and the linear receive filter are jointly optimized, and two provably convergent and low-complexity algorithms are developed. One algorithm can be applied to general system setups, but does not guarantee global optimality. The other is shown to be provably optimal in the special case of isotropic electromagnetic exposure constraints. The numerical results show that RIS-assisted communications can ensure high data rate transmissions while guaranteeing users' exposure constraints to radio frequency emissions

System-Level Modeling and Optimization of the Energy Efficiency in Cellular Networks -- A Stochastic Geometry Framework

In this paper, we analyze and optimize the energy efficiency of downlink cellular networks. With the aid of tools from stochastic geometry, we introduce a new closed-form analytical expression of the potential spectral efficiency (bit/sec/m$^2$). In the interference-limited regime for data transmission, unlike currently available mathematical frameworks, the proposed analytical formulation depends on the transmit power and deployment density of the base stations. This is obtained by generalizing the definition of coverage probability and by accounting for the sensitivity of the receiver not only during the decoding of information data, but during the cell association phase as well. Based on the new formulation of the potential spectral efficiency, the energy efficiency (bit/Joule) is given in a tractable closed-form formula. An optimization problem is formulated and is comprehensively studied. It is mathematically proved, in particular, that the energy efficiency is a unimodal and strictly pseudo-concave function in the transmit power, given the density of the base stations, and in the density of the base stations, given the transmit power. Under these assumptions, therefore, a unique transmit power and density of the base stations exist, which maximize the energy efficiency. Numerical results are illustrated in order to confirm the obtained findings and to prove the usefulness of the proposed framework for optimizing the network planning and deployment of cellular networks from the energy efficiency standpoint.Comment: To appear in IEEE Transactions on Wireless Communication

on simultaneous wireless information and power transfer for receive spatial modulation

International audience; In this paper, we study the performance of receive spatial modulation (RSM) with simultaneous wireless information and power transfer (SWIPT) capabilities. RSM is a multi-antenna modulation scheme, where the information bits are encoded into complex constellation symbols and the indices of the receive antennas. We show how RSM can be combined with SWIPT, by allowing the receivers to increase their data rate and, at the same time, to recharge their batteries. An optimization problem is formulated in order to optimize the fraction of transmit power to be used for information decoding and energy harvesting, as well as the covariance matrix of the energy waveform. Efficient numerical algorithms to tackle the associated optimization problems are proposed. Our analysis shows that RSM-SWIPT is a flexible transmission scheme that is capable of achieving different rate-energy demands. RSM-SWIPT, in particular, can be configured to leverage only the energy waveform for transmitting information data and power simultaneously. Compared with conventional SWIPT-enabled multiple-antenna systems, the proposed RSM-SWIPT scheme increases the amount of harvested energy for low values of the rate and avoids the need of using energy cancellation algorithms if information and power are transmitted only through the energy waveform

Scrivere la LIS con il Sign Writing. Manuale introduttivo

Abstract not availableQuesto manuale nasce da un\u27intuizione, quella di poter utilizzare un sistema per trascrivere la Lingua dei Segni Italiana (LIS), adattando ai segni italiani il Sign Writing, ideato nel 1995 da Valerie Sutton (1995) e proposto come "un alfabeto per scrivere le lingue dei segni". La LIS infatti, come le altre lingue dei segni, non ha una corrispettiva forma scritta ed è stata tramandata di generazione in generazione dalla comunità sorda. La mancanza di una forma scritta, del resto comune a molte altre lingue, ha avuto tutta una serie di implicazioni nella storia della comunità sorda e la possibilità di utilizzare un sistema di trascrizione - come ha detto Valerie Sutton - può aprire nuove frontiere della comunicazione per i segnanti. L\u27attuale generazione di persone sorde adulte, che sta imparando a leggere e a scrivere le lingue segnate per la prima volta, sta creando la base per il lavoro delle generazioni future

Towards Integrated Sensing and Communications for 6G: A Standardization Perspective

The radio communication division of the International Telecommunication Union (ITU-R) has recently adopted Integrated Sensing and Communication (ISAC) among the key usage scenarios for IMT-2030/6G. ISAC is envisioned to play a vital role in the upcoming wireless generation standards. In this work, we bring together several paramount and innovative aspects of ISAC technology from a global 6G standardization perspective, including both industrial and academic progress. Specifically, this article provides 6G requirements and ISAC-enabled vision, including various aspects of 6G standardization, benefits of ISAC co-existence, and integration challenges. Moreover, we present key enabling technologies, including intelligent metasurface-aided ISAC, as well as Orthogonal Time Frequency Space (OTFS) waveform design and interference management for ISAC. Finally, future aspects are discussed to open various research opportunities and challenges on the ISAC technology towards 6G wireless communications.Comment: 7 pages, 5 figure

Specific capture and whole‑genome phylogeography of Dolphin morbillivirus

Dolphin morbillivirus (DMV) is considered an emerging threat having caused several epidemics worldwide. Only few DMV genomes are publicly available. Here, we report the use of target enrichment directly from cetacean tissues to obtain novel DMV genome sequences, with sequence comparison and phylodynamic analysis. RNA from 15 tissue samples of cetaceans stranded along the Italian and French coasts (2008–2017) was purified and processed using custom probes (by bait hybridization) for target enrichment and sequenced on Illumina MiSeq. Data were mapped against the reference genome, and the novel sequences were aligned to the available genome sequences. The alignment was then used for phylogenetic and phylogeographic analysis using MrBayes and BEAST. We herein report that target enrichment by specific capture may be a successful strategy for whole-genome sequencing of DMV directly from field samples. By this strategy, 14 complete and one partially complete genomes were obtained, with reads mapping to the virus up to 98% and coverage up to 7800X. The phylogenetic tree well discriminated the Mediterranean and the NE-Atlantic strains, circulating in the Mediterranean Sea and causing two different epidemics (2008–2015 and 2014–2017, respectively), with a limited time overlap of the two strains, sharing a common ancestor approximately in 1998

Stereotactic body radiotherapy vs conventionally fractionated chemoradiation in locally advanced pancreatic cancer: A multicenter case‐control study (PAULA‐1)

The aim of this study was to compare two cohorts of LAPC patients treated with SBRT ± CHT vs CRT ± CHT in terms of local control (LC), distant metastases- free survival (DMFS), progression-free survival (PFS), overall survival (OS), and toxicity. Eighty patients were included. Patients in the two cohorts were matched ac- cording to: age ≤/>65 years, tumor diameter (two cut-offs

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population