Antonio De Maio’s research while affiliated with Consorzio Nazionale Interuniversitario per le Telecomunicazioni and other places

This work considers Maximum Likelihood Estimation (MLE) of a Toeplitz structured covariance matrix. In this regard, an equivalent reformulation of the MLE problem is introduced, and two iterative algorithms are proposed for the optimization of the equivalent statistical learning framework. Both strategies are based on the Majorization Minimization (MM) paradigm and hence enjoy nice properties such as monotonicity and ensured convergence to a stationary point of the equivalent MLE problem. The proposed framework is also extended to deal with MLE of other practically relevant covariance structures, namely, the banded Toeplitz, block Toeplitz, and Toeplitz-block-Toeplitz. Through numerical simulations, it is shown that the new methods provide excellent performance levels in terms of both mean square estimation error (which is very close to the benchmark Cramér-Rao Bound (CRB)) and signal-to-interference-plus-noise ratio, especially in comparison with state-of-the art strategies. Moreover, the estimation task is accomplished with a remarkable reduction in computational complexity compared with a standard approach relying on a Semidefinite Programming (SDP) solver.

This paper focuses on the experimental validation of probing signals designed to enable radar operation in spectrally crowded environments using an S-band Software Defined Radar (SDR). The tested waveforms ensure spectral coexistence between the sensing system and frequency-overlaid emitters, while optimizing radar performance. This is achieved through a bespoke notching of the radar signal spectrum to control the amount of interference injected by the radar in each shared frequency interval. Additionally, some relevant features of the probing signal that influence radar performance are controlled via a similarity index, describing the maximum allowable distance between the spectrally-notched waveform and a prescribed radar signal. In a first stage, the study is aimed at verifying whether the transmit and receive chains of the SDR system impair the spectral and temporal features of the designed waveforms. Subsequently, the tested signals are radiated into the environment to investigate their effectiveness to detect targets in the illuminated scene, as well as to ensure spectral coexistence in the presence of frequency-overlaid emitters. The results demonstrated that by exploiting the designed radar probing signals, the SDR system is capable of sharing spectrum with other RF wireless systems while also allowing to detect both stationary and moving targets.

The aim of the present study was to characterize, for the first time, the poly(ADP-ribosyl)ation system in the micro-crustacean copepod Temora stylifera, a widespread species in the coastal area of the Mediterranean Sea, and one of the dominant calanoid of the zooplankton assemblage in the Gulf of Naples. The analysis of endogenous poly(ADP-ribose) polymerases (PARPs) and poly (ADP-ribose) glycohydrolases’ (PARGs) expression, together with PARP activity, were studied in the eggs laid by the females collected during the peak of the seasonal population dynamic of this species. In parallel, PARP activity in the adult females and their produced eggs were also measured after exposure for 3 consecutive days to a cytotoxic phytoplankton diet, the dinoflagellate Alexandrium andersoni (ALEX). Females and eggs fed with a non-toxic diet, the dinoflagellate Prorocentrum minimum (PRO), were used as control. A specific T. stylifera PARP (TPARP) of about 50 kDa and a PARG enzyme of about 60 kDa were identified. PARP activity increased to about seven mU in both copepod females and eggs following exposure to ALEX, after 1 and 2 days of feeding, respectively. This biochemical response was mirrored by a decrease in female survival (69%) and egg hatching success (53%). We suppose that the increase of PARP activity is a response to oxidative stress and subsequent DNA damage, induced by ALEX diet on both copepod adults and on developing embryos. In conclusion, TPARP is suggested as a new and useful biomarker of health status in T. stylifera females and eggs.

This letter presents an iterative method to estimate directions of arrival (DOA) of plane wave signals impinging on a Uniform Circular Array (UCA), accounting for the possible presence of mutual coupling (MC). After a tailored transformation that maps the data gathered by the UCA into a Virtual Uniform Linear Array (VULA), the mutual coupling effect is modeled via gain and phase errors affecting the resulting VULA. Therefore, a Coordinate Descent (CD) iterative procedure is designed to approximate the maximum likelihood (ML) estimates of the VULA calibration factors and of the sources power. Leveraging the resulting calibrated VULA array manifold, the DOAs are obtained using the Estimation of Signal Parameters via Rotational Invariant Technique (ESPRIT). Simulation results demonstrate the superior performance of the proposed method with respect to the baseline uncalibrated ESPRIT, in terms of DOA estimation accuracy in the presence of mutual coupling, making it viable to be implemented in actual sensing systems due to its moderate computational complexity.

Multifunction phased array radars (MPARs) exploit the intrinsic flexibility of their active electronically steered array (ESA) to perform, at the same time, a multitude of operations, such as search, tracking, fire control, classification, and communications. This paper aims at addressing the MPAR resource allocation so as to satisfy the quality of service (QoS) demanded by both line of sight (LOS) and reflective intelligent surfaces (RIS)-aided non line of sight (NLOS) search operations along with communications tasks. To this end, the ranges at which the cumulative detection probability and the channel capacity per bandwidth reach a desired value are introduced as task quality metrics for the search and communication functions, respectively. Then, to quantify the satisfaction level of each task, for each of them a bespoke utility function is defined to map the associated quality metric into the corresponding perceived utility. Hence, assigning different priority weights to each task, the resource allocation problem, in terms of radar power aperture (PAP) specification, is formulated as a constrained optimization problem whose solution optimizes the global radar QoS. Several simulations are conducted in scenarios of practical interest to prove the effectiveness of the approach.

Multi-platform radar networks (MPRNs) are an emerging sensing technology due to their ability to provide improved surveillance capabilities over plain monostatic and bistatic systems. The design of advanced detection, localization, and tracking algorithms for efficient fusion of information obtained through multiple receivers has attracted much attention. However, considerable challenges remain. This article provides an overview on recent unconstrained and constrained localization techniques as well as multitarget tracking (MTT) algorithms tailored to MPRNs. In particular, two data-processing methods are illustrated and explored in detail, one aimed at accomplishing localization tasks the other tracking functions. As to the former, assuming an MPRN with one transmitter and multiple receivers, the angular and range constrained estimator (ARCE) algorithm capitalizes on the knowledge of the transmitter antenna beamwidth. As to the latter, the scalable sum-product algorithm (SPA) based MTT technique is presented. Additionally, a solution to combine ARCE and SPA-based MTT is investigated in order to boost the accuracy of the overall surveillance system. Simulated experiments show the benefit of the combined algorithm in comparison with the conventional baseline SPA-based MTT and the stand-alone ARCE localization, in a 3D sensing scenario.

Exosomes, which are small membrane‐encapsulated particles derived from all cell types, are emerging as important mechanisms for intercellular communication. In addition, exosomes are currently envisioned as potential carriers for the delivery of drugs to target tissues. The natural population of exosomes is very variable due to the limited amount of cargo components present in these small vesicles. Consequently, common components of exosomes may play a role in their function. We have proposed that membrane phospholipids could be a common denominator in the effect of exosomes on cellular functions. In this regard, we have previously shown that liposomes made of phosphatidylcholine (PC) or phosphatidylserine (PS) induced a robust alteration of macrophage (Mϕ) gene expression. We herewith report that these two phospholipids modulate gene expression in Mϕs by different mechanisms. PS alters cellular responses by the interaction with surface receptors, particularly CD36. In contrast, PC is captured by a receptor‐independent process and likely triggers an activity within endocytic vesicles. Despite this difference in the capture mechanisms, both lipids mounted similar gene expression responses. This investigation suggests that multiple mechanisms mediated by membrane phospholipids could be participating in the alteration of cellular functions by exosomes.