On chip interconnects for multiprocessor turbo decoding architectures

International audienc

Use of Nanoparticles as Nanoelectrodes in Contact-Less Cell Membrane Permeabilization by Time-Varying Magnetic Field: A Computational Study

This paper describes a computational approach for the assessment of electric field enhancement by using highly conductive gold nanoparticles (Au NPs) in time-varying electromagnetic fields cell membrane permeabilization, estimating the influence of the presence of Au NPs on transmembrane potential and on the pore opening dynamics. To account for variability and uncertainty about geometries and relative placement and aggregations of the Au NPs, three different NP configurations were considered: spherical Au NPs equally spaced around the cell; cubic Au NPs, for accounting for the possible edge effect, equally spaced around the cell; and spherical Au NPs grouped in clusters. The results show that the combined use of Au NPs and a time-varying magnetic field can significantly improve the permeabilization of cell membranes. The variability of NPs' geometries and configurations in proximity of the cell membrane showed to have a strong influence on the pore opening mechanism. The study offers a better comprehension of the mechanisms, still not completely understood, underlying cell membrane permeabilization by time-varying magnetic fields

Improving Network-on-Chip-based Turbo Decoder Architectures

In this work novel results concerning Networkon- Chip-based turbo decoder architectures are presented. Stemming from previous publications, this work concentrates first on improving the throughput by exploiting adaptive-bandwidth-reduction techniques. This technique shows in the best case an improvement of more than 60 Mb/s. Moreover, it is known that double-binary turbo decoders require higher area than binary ones. This characteristic has the negative effect of increasing the data width of the network nodes. Thus, the second contribution of this work is to reduce the network complexity to support doublebinary codes, by exploiting bit-level and pseudo-floatingpoint representation of the extrinsic information. These two techniques allow for an area reduction of up to more than the 40 % with a performance degradation of about 0.2 d

Un approccio integrato allo studio delle mappe di connettività funzionale cerebrale mediante elettroencefalografia e risonanza magnetica funzionale

Il contenuto di questa tesi volge ad esporre le recenti metodiche per lo studio integrato delle mappe funzionali cerebrali basate in particolare su EEG e fMRI. Si sono indagate le ragioni della scelta di queste due tecniche di neuroimaging e si analizza una loro applicazione ad un modello sperimentale condotto in condizione di riposo con lo scopo di individuare reti di connessione cerebrale nella connettività funzionale. Viene fatta una breve descrizione morfologica del cervello con un approfondimento sul funzionamento dell'attività elettrica dei neuroni. In seguito vengono illustrate le varie tecniche di indagine cerebrale, approfondendo i meccanismi dell'elettroencefalografia e della risonanza magnetica funzionale; di entrambe vengono descritti i principi fisici e la loro acquisizione del segnale. Infine viene mostrata l'integrazione dell'EEG con la fMRI ai fini di ottenere un'indagine cerebrale con ottima risoluzione sia spaziale che temporale. Di questa integrazione multimodale vengono elencati gli aspetti positivi e quelli più problematici, come l'introduzione di artefatti, che rendono difficile l'utilizzo del segnale per lo studio delle mappe di connessione cerebrale. Vengono quindi presentate le procedure di preprocessing sia dell'EEG che della fMRI utilizzate per migliorare i segnali al fine di renderli integrabili e un modello sperimentale che studia la connettività funzionale in Resting State Networks

Exposure Assessment for Wearable Patch Antenna Array at Millimeter Waves

International audienceThe upcoming deployment of wireless networks and systems operating in the upper part of the microwave spectrum, including millimeter-wave (mmWave) frequencies, motivates user exposure assessment studies at these emerging frequencies. At mmWaves, the power absorption is mainly limited to cutaneous and subcutaneous tissues. Till now, there is no literature consensus on the skin model to employ in computational exposure assessment studies. For these reasons, this work analyses four different models of the most superficial tissues with different degree of details exposed to wearable patch antennas operating at 28 GHz and 39 GHz. The results for the layered models are compared to the homogeneous one. Simulations were performed using the FDTD method, implemented in the Sim4life platform and the exposure was assessed in terms of the absorbed power density averaged over 1 cm2 and 4 cm2 (Sab). The data showed that the homogeneous model underestimates the peak value of Sab obtained for multi-layer models in the stratum corneum (by 8% to 12% depending on the number of layers of the model and the frequency) when the simulated models have the same reflection coefficient. Conversely, there are no substantial differences in the exposure levels between the layered models

Road User Exposure from ITS-5.9 GHz Vehicular Connectivity

This study addressed an important but not yet thoroughly investigated topic regarding human exposure to radio-frequency electromagnetic fields (RF-EMF) generated by vehicular connectivity. In particular, the study assessed, by means of computational dosimetry, the RF-EMF exposure in road users near a car equipped with vehicle-to-vehicle (V2V) communication antennas. The exposure scenario consisted of a 3D numerical model of a car with two V2V antennas, each fed with 1 W, operating at 5.9 GHz and an adult human model to simulate the road user near the car. The RF-EMF dose absorbed by the human model was calculated as the specific absorption rate (SAR), that is, the RF-EMF power absorbed per unit of mass. The highest SAR was observed in the skin of the head (34.7 mW/kg) and in the eyes (15 mW/kg); the SAR at the torso (including the genitals) and limbs was negligible or much lower than in the head and eyes. The SAR over the whole body was 0.19 mW/kg. The SAR was always well below the limits of human exposure in the 100 kHz–6 GHz band established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The proposed approach can be generalized to assess RF-EMF exposure in different conditions by varying the montage/number of V2V antennas and considering human models of different ages

Assessment of EMF Human Exposure Levels Due to Wearable Antennas at 5G Frequency Band

(1) Background: This work aims to assess human exposure to EMF due to two different wearable antennas tuned to two 5G bands. (2) Methods: The first one was centered in the lower 5G band, around f = 3.5 GHz, whereas the second one was tuned to the upper 5G band, at 26.5 GHz. Both antennas were positioned on the trunk of four simulated human models. The exposure assessment was performed by electromagnetic numerical simulations. Exposure levels were assessed by quantifying the specific absorption rate averaged on 10 g of tissue (SAR10g) and the absorbed power density (Sab), depending on the frequency of the wearable antenna. (3) Results: the higher exposure values that resulted were always mainly concentrated in a superficial area just below the antenna itself. In addition, these resulting distributions were narrowed around their peak values and tended to flatten toward lower values in farther anatomical body regions. All the exposure levels complied with ICNIRP guidelines when considering realistic input power. (4) Conclusions: This work highlights the importance of performing an exposure assessment when the antenna is placed on the human wearer, considering the growth of wearable technology and its wide variety of application, particularly regarding future 5G networks

Stochastic Dosimetry Assessment of Human RF-EMF Spatial Exposure Variability in 5G-V2X Vehicular Communication Scenario

The present work was focused on assessing the spatial exposure variability for pedestrians on the road, in close proximity to a car equipped with a 5G-V2X antenna, operating at the working frequency of 3.5 GHz and with 3D beamforming capability. Indeed, Cooperative Intelligent Transportation Systems (C-ITS) will soon utilize 5G New-Radio (NR) wireless communication to overcome the limitations of the current V2X (Vehicle-to-Everything) wireless communication technologies, enhancing road-safety and driving efficiency. However, this transition also introduces heterogeneity, uncertainty and variability in the radio frequency (RF) exposure levels of pedestrian and other road-users. To evaluate the spatial exposure variability in these new 5G-V2X scenarios, in this work we adopted an approach which combines a stochastic (metamodeling) technique called Polynomial Chaos Kriging with deterministic dosimetry (classical computation techniques). By utilizing this approach, we were able to assess the exposure levels, expressed in terms of specific absorption rate (SAR), for 1000 different beamforming patterns of the 5G-V2X antenna, with low computational cost. The results showed low exposure values compared to ICNIRP guidelines and highlighted a high exposure variability for 5G vehicular communication scenarios

Assessment of SAR in Road-Users from 5G-V2X Vehicular Connectivity Based on Computational Simulations

(1) Background: Cooperative Intelligent Transportation Systems (C-ITS) will soon operate using 5G New-Radio (NR) wireless communication, overcoming the limitations of the current V2X (Vehicle-to-Everything) wireless communication technologies and increasing road-safety and driving efficiency. These innovations will also change the RF exposure levels of pedestrians and road-users in general. These people, in fact, will be exposed to additional RF sources coming from nearby cars and from the infrastructure. Therefore, an exposure assessment of people in the proximity of a connected car is necessary and urgent. (2) Methods: Two array antennas for 5G-V2X communication at 3.5 GHz were modelled and mounted on a realistic 3D car model for evaluating the exposure levels of a human model representing people on the road near the car. Computational simulations were conducted using the FDTD solver implemented in the Sim4Life platform; different positions and orientations between the car and the human model were assessed. The analyzed quantities were the Specific Absorption Rate on the whole body (SARwb), averaged over 10 g (SAR10g) in specific tissues, as indicated in the ICNIRP guidelines. (3) Results: the data showed that the highest exposure levels were obtained mostly in the head area of the human model, with the highest peak obtained in the configuration where the main beam of the 5G-V2X antennas was more direct towards the human model. Moreover, in all configurations, the dose absorbed by a pedestrian was well below the ICNIRP guidelines to avoid harmful effects. (4) Conclusions: This work is the first study on human exposure assessment in a 5G-V2X scenario, and it expands the knowledge about the exposure levels for the forthcoming use of 5G in connected vehicles