Search results for "automatic"

A control strategy based on intelligent algorithm (PSO) to perform electrical stimulation systems

2017

International audience; Adjusting stimulation parameters using control strategy based on reliable mathematical model that can predict perfectly the muscle response, may improve the efficiency of Functional Electrical Stimulation (FES) systems. In the present project, we investigate the PID control tuning based on the Particle Swarm Optimization (PSO) algorithm at the first time in neuro-muscular systems for updating automatically the stimulation pulse amplitude to track a desired force profiles. In the beginning, The PSO algorithm is used to identify unknown force model parameters. Next, optimal PID gains are found by the same intelligent algorithm to improve the control system. The obtaine…

Automated Checking of Flexible Mathematical Reasoning in the Case of Systems of (In)Equations and the Absolute Value Operator

2021

We present an approach and a tool for automatically providing feedback on solutions that involve complicated reasoning patterns. Currently the tool supports linear systems of equations and inequations that may also contain the absolute value operator and a restricted form of rational functions. This suffices for designing problems that are laborious to solve with standard mechanical procedures, but much easier using short-cuts that students may find by creative thinking. Earlier research has found that struggling with important mathematics promotes conceptual development. Our goal is to encourage students to such struggling. A crucial feature is to give them great freedom to choose the path…

Analysis of MAC-level throughput in LTE systems with link rate adaptation and HARQ protocols

2015

LTE is rapidly gaining momentum for building future 4G cellular systems, and real operational networks are under deployment worldwide. To achieve high throughput performance, in addition to an advanced physical layer design LTE exploits a combination of sophisticated mechanisms at the radio resource management layer. Clearly, this makes difficult to develop analytical tools to accurately assess and optimise the user perceived throughput under realistic channel assumptions. Thus, most existing studies focus only on link-layer throughput or consider individual mechanisms in isolation. The main contribution of this paper is a unified modelling framework of the MAC-level downlink throughput of …

Editorial: On the Nature and Scope of Habits and Model-Free Control

2021

Active disturbance rejection control of linear induction motor

2017

This paper proposes the theoretical framework and the experimental application of the active disturbance rejection control to linear induction motors. Such a nonlinear control (ADRC) technique can be viewed as a particular kind of input-output linearization control, where the nonlinear transformation of the state is not computed by means of the model, but it is estimated online. Such an approach permits to cope with unmodelling dynamics, as well as uncertainty in the knowledge of the model parameters and exogenous disturbances. The effectiveness of the proposed ADRC control law has been verified both by numerical simulations and experimentally on a suitably developed test setup. Moreover, t…

Optimal Resource Allocation in Multi-Hop Networks: Contention vs. Scheduling

2014

CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) is actually the most used method in ad-hoc networks for transmitting on a contending medium, even if it shows poor performance in presence of hidden nodes. To increase performance, we propose an algorithm that combines CSMA and TDMA (Time Division Multiple Access) approaches. The adopted solution consists of grouping contending nodes in non-interfering subsets and granting a different numbers of time slots to different groups, while using the CSMA to manage medium access among nodes belonging to the same subset. An optimization procedure to assign the time slots to each subset of nodes and to find an equilibrium between contention …

Stiffness Estimation and Adaptive Control for Soft Robots

2022

Nonostante la sorprendente crescita nello sviluppo dei robot ispirati alla natura, tra cui i cosiddetti soft robot, il potenziale di questi sistemi, che hanno intrinseche capacità di adattamento, non è ancora stato sfruttato a pieno. La ricerca ha principalmente considerato il controllo in retroazione della posizione dei giunti del robot, lasciando la gestione della cedevolezza di questi ultimi ancora in anello aperto. Peraltro, le attuali limitazioni nel processo di produzione degli attuatori a cedevolezza variabile e l'inevitabile variabilità nel tempo degli elementi elastici costitutivi, i quali sono soggetti ad usura e deformazione plastica, rendono il problema della determinazione prec…

Habit and physical activity: Theoretical advances, practical implications, and agenda for future research

2019

Abstract Objective Understanding habits may inform intervention development aimed at promoting physical activity maintenance for long-term health. In the present article, I review theory and research on habits applied to physical activity. I provide an overview of contemporary conceptualizations of habit and habit theory; address whether or not physical activity can be habitual; review perspectives on how physical activity habits develop; summarize research on effects of physical activity habits; identify intervention strategies effective in promoting physical activity habits; and propose an agenda for future research on physical activity habits. Design and Methods Conceptual and narrative …

Habit and physical activity : Theoretical advances, practical implications, and agenda for future research

2018

Objective: Understanding habits may inform intervention development aimed at promoting physical activity maintenance for long-term health. In the present article, I review theory and research on habits applied to physical activity. I provide an overview of contemporary conceptualizations of habit and habit theory; address whether or not physical activity can be habitual; review perspectives on how physical activity habits develop; summarize research on effects of physical activity habits; identify intervention strategies effective in promoting physical activity habits; and propose an agenda for future research on physical activity habits. Design and Methods: Conceptual and narrative review.…

Opportunistic Synchronization for Improving IEEE 802.15.4 MAC Performance in Chain Topologies

2010

The most effective solution for energy saving in low-rate wireless sensor networks is maintaining each node in a doze state as long as possible. In order to guarantee network connectivity, the intervals at which the network sensors are turned on and off have to be coordinated. Therefore, synchronization is a very critical function for sensor networks. In this paper, we analyze the IEEE 802.15.4 MAC performance in sensor networks deployed in a chain topology. For this topology, critical inefficiencies can arise in case of multi-hop packet deliveries. We evaluate the impact of different synchronization schemes on the network performance, both in terms of network throughput and in terms of ene…