Search results for "Node"
showing 10 items of 1701 documents
Minimum Losses Reconfiguration of MV Distribution Networks through Local Control of Tie Switches
2002
This paper deals with the problem of optimal reconfiguration of radial distribution networks for minimum loss operation. The proposed control strategy of the open-closed status of the tie-switches is distributed, since every MV/LV node is provided with local controllers having some measured entities as input. It also does not prevent the system from the future implementation of centralized control; instead it may represent the first step toward a complete automation of the distribution system. The proposed strategy is indeed organized in hierarchic levels, the highest of which may be in the future a central control. After introducing the general problem of networks reconfiguration, a review…
RF-based node system for blind navigation in running activities
2008
The system presented is oriented for use by blind adults or children in running activities at a stadium or an analogical large space. The system dynamically provides a blind person with navigation related information. Radio signal strength measurements are used in localization task. The system makes a blind person more independent in sport, eliminating the need in explicit human assistance.
Split-Delivery Capacitated Arc-Routing Problem: Lower Bound and Metaheuristic
2010
International audience; This paper proposes lower and upper bounds for the split-delivery capacitated arc-routing problem (SDCARP), a variant of the capacitated arc-routing problem in which an edge can be serviced by several vehicles. Recent papers on related problems in node routing have shown that this policy can bring significant savings. It is also more realistic in applications such as urban refuse collection, where a vehicle can become full in the middle of a street segment. This work presents the first lower bound for the SDCARP, computed with a cutting plane algorithm and an evolutionary local search reinforced by a multistart procedure and a variable neighborhood descent. Tests on …
Synergistic Use of Electrochemical Impedance Spectroscopy and Photoelectrochemical Measurements for Studying Solid State Properties of Anodic HfO2
2017
Within the past years, intense research has been carried out on HfO2 as high k material, promising candidate to replace SiO2 as gate dielectric in CMOS based devices (1), and as metal oxide for resistive random access memory (ReRAM) (2). For both technological applications compact, uniform and flat oxides are necessary, and a detailed understanding of their physical properties as a function of the fabrication conditions is strongly. Hafnia performance can be significantly influenced by carrier trapping taking place at pre-existing precursors states (induced by oxygen vacancies, interstitial ions, impurities acting as dopants), or by self-trapping in a perfect lattice, where the potential we…
A tunnel magnetoresistive effect wattmeters-based wireless sensors network
2017
Abstract In the present work a wireless sensors network (WSN) for smart energy metering is presented using the ZigBee protocol as the communication link. Each network node process the electrical power by means of a Wheatstone bridge sensor based on the tunnel magnetoresistive (TMR) effect working as analogue multiplier. The electrical power is acquired and processed by a digital signal processor that extracts various parameters of interest like current and voltage load, active power and power factor by means of Fourier analysis. All the obtained electrical parameters at each node are served and shown in a web page that can be easily accessed by authorized users.
Modelling of single cell solid oxide fuel cells using COMSOL multiphysics
2017
Solid oxide fuel cells (SOFCs) have the potential to become one of the efficient and cost effective systems for direct conversion of a wide variety of fuels to electricity. In this study, we developed a three-dimensional multiphysics model for a single cell SOFC using COMSOL multiphysics (version 5.2) software and performed simulations to examine the effect of gas flow patterns (radial flow and counter flow) in different operating temperatures (700° C, 800° C and 1000° C) for a planar anode supported SOFC. With the help of the simulation results, we have analyzed the electrical characteristics of the single cell SOFCs. From the simulation results, it is observable that the radial gas flow p…
A Comparative Analysis of the Reliability of Simple and Two-Level Checkpointing Techniques in two Different Distributed Industrial Control System Arc…
2003
In Distributed industrial control systems it is necessary to guarantee certain reliability level. In this sense, Checkpointing and Rollback techniques offer interesting possibilities to achieve fault tolerance without appreciable cost and complexity increment. Several Checkpointing techniques have been proposed. Most of them suppose the presence of stable storage in the system. But distributed industrial control systems usually do not dispose of this kind of storage. So, another storage strategy has to be employed. If Checkpoints were locally stored (Simple Checkpointing), the system tolerates only transient faults. If Checkpoints were locally, at the same node, and, additionally, at anothe…
A new backward/forward method for solving radial distribution networks with PV nodes
2008
Abstract In this paper, a new backward/forward (b/f) methodology for the analysis of distribution systems with constant power loads is presented. In the proposed method, at each iteration, the loads are considered as constant impedances; in the backward sweep all the network variables (bus voltages and branch currents) are evaluated considering a scaling factor which is determined at the end of the backward phase. Indeed the forward sweep is eliminated and the node voltages calculation does not demand the sequentiality needed in the b/f methodology. The developed method, although deriving conceptually from the b/f methodology, presents only the backward phase in which all the network variab…
Medición del efecto látigo en redes de suministro
2016
La variabilidad de la demanda que se origina de un agente a otro en la cadena de suministro, aumenta o amplifica a medida que la señal se aleja del punto de origen; estas distorsiones se denominan Efecto Látigo. En este artículo se aborda una red de suministros multieslabón, que estima los intervalos de medición de la distorsión de la demanda de la red, de acuerdo a comportamientos extremos en el sistema que permiten diagnosticar su desempeño en términos de la amplificación de demanda. Para la investigación se aplican mediciones estáticas locales y globales del efecto látigo, en cada nivel de la red de suministros del juego de la cerveza de cuatro eta-pas; cada etapa o eslabón tiene múltipl…
A Simple Method to Assess Loadability of Radial Distribution Networks
2005
This paper proposes a simple method to asses loadability in radial distribution systems. The relevant problem of voltage stability has been dealt with in past times with reference to higher voltage systems for generation and transmission. In more recent papers, the problem has been considered also at distribution level, since the new electrical energy market requirements and the increasing loadings are now more and more influencing these systems. The proposed method is based on a static approach and proceeds by first evaluating the stability indices and then the different loadability factors (related to real, reactive and apparent power). These calculations are carried out by identifying, s…