Model of Switched-Capacitor Programmable Voltage Reference: Optimization for Ultra Low-Power Applications

This paper proposes an analytical model for the optimized design of a switched-capacitor programmable voltage reference (SC-PVREF). This PVREF topology guarantees a straightforward design, easy portability across different technology nodes, and does not require any special technology option. The developed model allows the study of the trade-offs and the a priori evaluation of the system performance. Circuit optimization is carried out with MATLAB and permits SC-PVREF to achieve current consumptions of tens of nanoampere, suitable for ultra low-power applications

Asymptotics as s→0+s \to 0^+ of the fractional perimeter on Riemannian manifolds

In this work we find the asymptotic behaviour as $s\to 0^+$ of the fractional $s$-perimeter $P_s(E,\Omega)$ of a set $E$ in a domain $\Omega \subset M$, when the ambient space is any complete Riemannian manifold $(M,g)$. Prior to the present work, the asymptotic was studied in only two very specific cases where the explicit form of the heat kernel is known: on $\R^n$ in [11] and recently on the Gaussian space in [8]. The limit is different in this two cases. Somehow surprisingly, we show that the latter behaviours are the only two possible under very general assumptions. \vsp In the case of complete manifolds with finite volume, we find that the limit is a sort of localized Riemannian volume invariant under complementation. Our proofs are robust and they apply verbatim to the case of weighted Riemannian manifolds, thus implying the result in [8]. \vsp On the other hand, for stochastically complete Riemannian manifolds with infinite volume and having the $L^\infty-{\rm Liouville}$ property, we extend the classical result in [11] for the standard $s$-perimeter in $\R^n$, and we show an analogous behavior in the limit. Moreover, even when the $L^\infty-{\rm Liouville}$ property does not hold our proof still holds and exploits a link between the asymptotics of the fractional Laplacian (and of the fractional perimeter) and the existence of bounded harmonic functions on $M$.Comment: 39 pages, modified introduction, added Theorem 1.

Designing Distributed, Component-Based Systems for Industrial Robotic Applications

none3noneM. Amoretti; S. Caselli; M. ReggianiM., Amoretti; S., Caselli; Reggiani, Monic

Memory Devices and A/D Interfaces: Design Trade-offs in Mixed-Signal Accelerators for Machine Learning Applications

This tutorial focuses on memory elements and analog/digital (A/D) interfaces used in mixed-signal accelerators for deep neural networks (DNNs) in machine learning (ML) applications. These very dedicated systems exploit analog in-memory computation (AiMC) of weights and input activations to accelerate the DNN algorithm. The co-optimization of the memory cell storing the weights with the peripheral circuits is mandatory for improving the performance metrics of the accelerator. In this tutorial, four memory devices for AiMC are reported and analyzed with their computation scheme, including the digital-to-analog converter (DAC). Moreover, we review analog-to-digital converters (ADCs) for the quantization of the AiMC results, focusing on the design trade-offs of the different topologies given by the context

Regularity results for solutions to obstacle problems with Sobolev coeffcients

We establish the higher differentiability of solutions to a class of obstacle problems for integral functionals where the convex integrand f satisfies p-growth conditions with respect to the gradient variable. We derive that the higher differentiability property of the weak solution v is related to the regularity of the assigned , under a suitable Sobolev assumption on the partial map that measures the oscillation of f with respect to the x variable. The main novelty is that such assumption is independent of the dimension n and that, in the case p<=n-2, improves previous known results

Power Management Circuits for Low-Power RF Energy Harvesters

The paper describes the design and implementation of power management circuits for RF energy harvesters suitable for integration in wireless sensor nodes. In particular, we report the power management circuits used to provide the voltage supply of an integrated temperature sensor with analog-to-digital converter. A DC-DC boost converter is used to transfer efficiently the energy harvested from a generic radio-frequency rectifier into a charge reservoir, whereas a linear regulator scales the voltage supply to a suitable value for a sensing and conversion circuit. Implemented in a 65 nm CMOS technology, the power management system achieves a measured overall efficiency of 20%, with an available power of 4.5 μW at the DC-DC converter input. The system can sustain a temperature measurement rate of one sample/s with an RF input power of −28 dBm, making it compatible with the power levels available in generic outdoor environments

Widespread Urban Regeneration of Existing Residential Areas in European Medium-Sized Cities. A Framework to Locate Redevelopment Interventions

Within the scientific debate on urban regeneration, this paper intends to question possible planning techniques to address the implementation of widespread regeneration interventions in obsolete residential areas within medium-sized European cities, with particular attention to constructing a cognitive framework to locate redevelopment interventions. The widespread urban regeneration approach has yet to be sufficiently explored in the scientific literature, which focuses much more on replacing large derelict areas, though it seems particularly relevant for research and urban practice. This paper aims to illustrate a methodological framework for defining obsolete and degraded areas (at the block scale) suitable for redevelopment. Various criteria are considered, e.g., land use, buildings’ dating, state of preservation, population density, public spaces, and facility provision, and degree of accessibility. The methodological framework is then tested in the medium-sized Italian city of Parma. Data set parameters and threshold values to quantify the previously introduced criteria and perform GIS-based statistical and spatial analysis. The results show 96 areas potentially in need of regeneration, providing an opportunity to reflect on the criteria of suitability and priority for transformation and the framework of past and future planning scenarios

CMOS Interface Circuits for High-Voltage Automotive Signals

Abstract: The acquisition of high-voltage signals from sensors and actuators in an internal-combustion engine is often required for diagnostic purposes or in the case of conversion to alternative fuels, such as hydrogen, natural gas, or biogas. The integration of electronic interfaces and acquisition circuits in a single device provides benefits in terms of component-count reduction and performance. Nonetheless, the high voltage level of the involved signals makes on-chip design challenging. Addi- tionally, the circuits should be compatible with the CMOS technology, with limited use of high-voltage options and a minimum number of off-chip components. This paper describes the design and the implementation in 350 nm CMOS technology of electronic interfaces and acquisition circuits for typical high-voltage signals of automotive context. In particular, a novel co-design of dedicated voltage clamps with electro-static discharge (ESD) protections is described. The proposed circuits require only a single off-chip resistor, and they are suitable for the acquisition of signals with peak voltages up to 400 V. The measured performance of the silicon prototypes, in the [−40 °C, +125 °C] temperature range, make the proposed electronic interfaces suitable for the automotive domain

Exploring the 15-minute neighbourhoods. An evaluation based on the walkability performance to public facilities

Recent trends in urban policies are rediscovering a new focus on different urban life models that exclude the obsolete vehicle model and lead to renewed attention on the proximity dimension and active mobility. This vision takes concrete form in the concept of the 15-minute city model, focused on pedestrian accessibility from one’s home to nearby urban services and spaces. In this perspective, the paper aims at exploring the theme of 15-minute cities through a GIS-based model to evaluate pedestrian accessibility to neighbourhood facilities. The implemented methodology integrates the assessment of walking distances, considering the time factor as crucial, and mapping the resident population. The method is then applied to measure the current performances of an existing neighbourhood in Parma from the 15 minutes city perspective, assessing accessibility based on home-facility travel times and the resident population distribution within reach. A reflection is proposed on what has been learned and on the possible contribution that the method can bring to monitoring the 15-minute city and to urban planning