Photocurrent-based detection of Terahertz radiation in graphene

Graphene is a promising candidate for the development of detectors of Terahertz (THz) radiation. A well-known detection scheme due to Dyakonov and Shur exploits the confinement of plasma waves in a field-effect transistor (FET), whereby a dc photovoltage is generated in response to a THz field. This scheme has already been experimentally studied in a graphene FET [L. Vicarelli et al., Nature Mat. 11, 865 (2012)]. In the quest for devices with a better signal-to-noise ratio, we theoretically investigate a plasma-wave photodetector in which a dc photocurrent is generated in a graphene FET. The rectified current features a peculiar change of sign when the frequency of the incoming radiation matches an even multiple of the fundamental frequency of plasma waves in the FET channel. The noise equivalent power per unit bandwidth of our device is shown to be much smaller than that of a Dyakonov-Shur detector in a wide spectral range.Comment: 5 pages, 4 figure

A flexible sensor technology for the distributed measurement of interaction pressure

We present a sensor technology for the measure of the physical human-robot interaction pressure developed in the last years at Scuola Superiore Sant'Anna. The system is composed of flexible matrices of opto-electronic sensors covered by a soft silicone cover. This sensory system is completely modular and scalable, allowing one to cover areas of any sizes and shapes, and to measure different pressure ranges. In this work we present the main application areas for this technology. A first generation of the system was used to monitor human-robot interaction in upper- (NEUROExos; Scuola Superiore Sant'Anna) and lower-limb (LOPES; University of Twente) exoskeletons for rehabilitation. A second generation, with increased resolution and wireless connection, was used to develop a pressure-sensitive foot insole and an improved human-robot interaction measurement systems. The experimental characterization of the latter system along with its validation on three healthy subjects is presented here for the first time. A perspective on future uses and development of the technology is finally drafted

A Wireless Flexible Sensorized Insole for Gait Analysis

This paper introduces the design and development of a novel pressure-sensitive foot insole for real-time monitoring of plantar pressure distribution during walking. The device consists of a flexible insole with 64 pressure-sensitive elements and an integrated electronic board for high-frequency data acquisition, pre-filtering, and wireless transmission to a remote data computing/storing unit. The pressure-sensitive technology is based on an optoelectronic technology developed at Scuola Superiore Sant'Anna. The insole is a low-cost and low-power battery-powered device. The design and development of the device is presented along with its experimental characterization and validation with healthy subjects performing a task of walking at different speeds, and benchmarked against an instrumented force platform

Distribution Network Models platform guideline

The Distribution Network Model (DiNeMo) is the collaborative platform where it is possible to model the electricity distribution grids of your community, city or region. This document provide a helpful guideline to the user.JRC.C.3-Energy Security, Distribution and Market

A robust resource allocation algorithm for packet BIC-UFMC 5G wireless communications

In this paper, we present a novel resource allocation (RA) algorithm for packet Universal Filtered Multi-Carrier (UFMC) BIC-based communications, the latter being a novel modulation format possibly envisaged to be applied in 5G wireless systems. Assuming the perfect knowledge of the channel and capitalizing on the specific UFMC signal waveform, the proposed RA strategy optimizes the coding rate and bit loading within the overall bandwidth along with the per-subband power distribution. In the presence of a carrier offset and over fading selective channels, the results we obtained are twofold: i) the UFMC format reveals to be more robust than the conventional OFDM scheme; ii) the performance of the UFMC system itself is further boosted by the optimal choice of radio resources evaluated by the proposed RA algorithm

A novel hand exoskeleton with series elastic actuation for modulated torque transfer

Abstract Among wearable robotic devices, hand exoskeletons present an important and persistent challenge due to the compact dimensions and kinematic complexity of the human hand. To address these challenges, this paper introduces HandeXos-Beta (HX-β), a novel index finger-thumb exoskeleton for hand rehabilitation. The HX-β system features an innovative kinematic architecture that allows independent actuation of thumb flexion/extension and circumduction (opposition), thus enabling a variety of naturalistic and functional grip configurations. Furthermore, HX-β features a novel series-elastic actuators (SEA) architecture that directly measures externally transferred torque in real-time, and thus enables both position- and torque-controlled modes of operation, allowing implementation of both robot-in-charge and user-in-charge exercise paradigms. Finally, HX-β's adjustable orthosis, passive degrees of freedom, and under-actuated control scheme allow for optimal comfort, robot-user joint alignment, and flexible actuation for users of various hand sizes. In addition to the mechatronic design and resulting functional capabilities of HX-β, this work presents a series of physical performance characterizations, including the position- and torque-control system performance, frequency response, end effector force, and output impedance. By each measure, the HX-β exhibited performance comparable or superior to previously reported hand exoskeletons, including position and torque step response times on the order of 0.3 s, −3 dB cut-off frequencies ranging from approximately 2.5 to 4 Hz, and fingertip output forces on the order of 4 N. During use by a healthy subject in torque-controlled transparent mode, the HX-β orthosis joints exhibited appropriately low output impedance, ranging from 0.42 to −0.042 Nm/rad at 1 Hz, over a range of functional grasps performed at real-life speeds. This combination of lab bench characterizations and functional evaluation provides a comprehensive verification of the design and performance of the HandeXos Beta exoskeleton, and its suitability for clinical application in hand rehabilitation

Distribution System Operators Observatory 2018

The distribution system is a key part of the electricity chain. It links bulk production with end consumers. Recently, radical changes have taken place in every segment of the power industry. These are calling for a changing role of the Distribution System Operators (DSOs) in Europe. This report provides a clear picture of the features of distribution grids in Europe, on the way they are operated and how far DSOs are from the paved provisions proposed in the recent Electricity Directive of the European Commission.JRC.C.3-Energy Security, Distribution and Market

Perceived organizational support and work engagement: the role of psychosocial variables

PurposeThis study aims to test the role that organizational sociopsychological variables may play in influencing job stress and work engagement in an organizational identity change scenario.Design/methodology/approachOn a sample of 118 employees of an Italian company in the personnel training services sector, multivariate statistical analysis tests a pattern where organizational variables such as work support (by supervisors and coworkers, independent variables) – moderated by corporate identification (moderating variable) – and mediated by organizational trust (mediating variable) – boosts employee work engagement and lowers psychosocial risks (dependent variables).FindingsThe mediating effect of "organizational trust" is significant in the relationships of "supervisor social support" and "coworker social support" with the "absence of psychosocial risks." Moreover, an increase in supervisor social support can lead to a statistically significant increase in work engagement. This occurs only for employees with low or medium identification and not in highly identified individuals.Originality/valueThe findings from the analysis on moderation are of primary importance because they show us a new perspective that can play the role of a guiding and practical principle on how to act on an organization's human resources, specifically targeting those with lower or medium corporate identification