Search results for "working"
showing 10 items of 2747 documents
NB PLC and Software Defined Networking for Smart Grid Applications
2017
During the last years, the installation of Distributed Energy Resources (DERs) and the expected diffusion of Electrical Vehicles (EVs), is increasing the complexity of the distribution grid, making the management of the grid operated by Distribution System Operators (DSOs) more difficult. The Smart Grid approach tries to provide a response to these troubles, by means of a strong interaction between the power grid and Information and Communication Technology (ICT) infrastructures. The drawback of this approach is an increase in the management effort of the ICT infrastructures, for which the DSO are not prepared. Software Defined Networking (SDN) is an approach developed to manage complex ICT…
A robust calibration methodology for an On-Board Diagnostic car system
2006
New car models are now by law equipped with on-board diagnostic (OBD) systems aimed at monitoring the state of health of strategic components that ensure low levels of polluting exhaust emissions. During development phases, for each new car model, the OBD system must be finely calibrated. This article presents a robust calibration methodology taking into account sources of variability mainly due to production process, operating, and environmental conditions. The methodology enables us to evaluate the false alarm and failure to detect risks intrinsically related to the adopted calibration. An application concerning an upstream oxygen sensor monitored by the OBD is presented.
A New Measurement Method for the Detection of Harmonic Sources in Power Systems Based on the Approach of the IEEE Std. 1459–2000
2010
In this paper, a novel single-point strategy is proposed for the detection of the harmonic sources in power systems. The method is an improvement of a strategy previously proposed by the authors; it is developed from the IEEE Std 1459-2000 approach and it can be entirely implemented in the time domain, thus simplifying the measurement system. The effectiveness of the proposed method is evaluated by introducing simple decision-making rules and by taking the presence of the measurement transducers into account. Several simulations and experimental tests are presented, showing that the enhanced strategy is able to give an useful information on the detection of the dominant harmonic source upst…
Aggregated Packet Transmission in Duty-Cycled WSNs: Modeling and Performance Evaluation
2017
[EN] Duty cycling (DC) is a popular technique for energy conservation in wireless sensor networks (WSNs) that allows nodes to wake up and sleep periodically. Typically, a single-packet transmission (SPT) occurs per cycle, leading to possibly long delay. With aggregated packet transmission (APT), nodes transmit a batch of packets in a single cycle. The potential benefits brought by an APT scheme include shorter delay, higher throughput, and higher energy efficiency. In the literature, different analytical models have been proposed to evaluate the performance of SPT schemes. However, no analytical models for the APT mode on synchronous DC medium access control (MAC) mechanisms exist. In this …
Sensorless control of PMSM by a linear neural network: TLS EXIN neuron
2010
Sensorless vector control applied to the Permanent Magnet Synchronous Motors (PMSMs) is a very challenging subject. It permits obtaining high dinamical performance by exploiting increased reliability and also reduced cost. Among the different methodologies proposed in literature, a model based approach has been proposed here. In particular, the space vector equations of the PMSM have been re-elaborated to permit the use of a Least Squares technique. The problem has been then faced-up to with the so-called TLS EXIN neuron, which is a linear neural network able to solve the TLS problem on-line. Simulation tests have been done on both interior mounted and surface mounted machines.
Advanced refrigerating plants based on transcritical cycles working with carbon dioxide for commercial refrigeration
2012
Supermarkets and hypermarkets require a huge amount of energy to maintain chilled and frozen food in product display cases and cold storage rooms and thermal comfort in the whole building. Systems exploited require very large refrigerant charges for operation and suffer significant leakages. The challenge for advanced systems, based on equipment which reduce TEWI, suggests the proposal of carbon dioxide: a natural working fluid. This paper deals with a feasibility study of a refrigerating system for a big hypermarket in Sicily based on a three-stage transcritical cycle working with carbon dioxide which is compared with an alternative system composed of two cycles operating as a binary refri…
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.
Fuzzy topology discovery protocol for SDN-based wireless sensor networks
2017
Abstract The growing trend in pervasive systems forces traditional wireless sensor networks to deal with new challenges, such as dynamic application requirements and heterogeneous networks. One of the latest paradigms in this area is software defined wireless sensor network. According to the paradigm, the networks take care of managing topological information and forwarding decisions using a bipartite architecture in which a control plane decides the forwarding policies and the data plane (i.e. ordinary sensor nodes) executes them. Unfortunately, in highly dynamic networks, this approach generates an overhead of control packet exchange between the ordinary nodes and the control plane, that …
A Novel Wireless Sensor Network for Electric Power Metering
2015
Wireless sensor network with lightweight and efficient communication infrastructures are today a great interest, both at research and industrial level, as they are the basis for reliable monitoring services. Mesh networks are ideal candidates in this scenario, as they can be very fault-tolerant. After introducing wireless network systems requirements, we show the design of a mesh network routing protocol based on AODV schemas. Its implementation runs on top of low-cost off-the-shelf components, and allowed us to build a custom power meter wireless sensor node.
Narrowband digital filtering with random frequency hopping spread spectrum
2014
International audience; In digital signal filtering, channels with narrow bandwidth need high order digital filter to be selected without introducing modulation errors. If a carrier randomly switches from a channel to another as in military applications, or some civilian communication standards, it is necessary to detect and estimate these jumps before transposing and analyzing signals in the baseband. This paper presents a real time solution to filter narrow band signals with random frequency hopping spread spectrum. The proposed method is based on three steps. Firstly, the detection of Signal Frequency Hopping (SFH) using the Fast Fourier Transform (FFT), an algorithm to estimate the Domi…