Search results for "Location"

A New Mathematical Approach for Faults Identification and Location in Distribution Systems

2009

The paper presents a new methodology for fault identification and location in electrical distribution systems, based on the use of a lumped parameter representation of the faulted line and on a matrix approach. Utilities are quite interested in such items, since the new required quality standards put severe constraints on faults management and clearance.

A New Protection Strategy for Electrical Distribution Systems

2010

In this paper, the authors propose a new protection strategy for electrical Medium Voltage distribution networks, based on a distributed intelligence system composed of a central unit and of many local processing units. The distributed intelligence system can precisely identify and locate faults in suitably limited times. Each local processing unit is composed of a data acquisition system and a data analysis system. The first allows the accurate reconstruction of the fundamental using only 1.5 cycles of under fault transient electrical quantities. The second performs suitably precise on-line fault diagnosis based on the data provided by the data acquisition module. The data acquisition algo…

DESIGN OF A FAULT AND PARTIAL DISCHARGES LOCATION DEVICE FOR CABLE POWER NETWORK

In this thesis, a digital device for fault and on line partial discharge location is presented. The device employs the traveling wave method for two or multiple ends. The designed prototype shows interesting features connected to the low cost and to the possibility to collect data from different locations thus providing additional functionalities deriving from pre-fault and data analysis, relating the existence of defects to the subsequent fault event. The device also enables the acquisition of the temperature on the cable section where the sensor is installed. Such installation can also support DSO and TSO for carrying out both on-event and condition based maintenance, discovering the caus…

Realizing airtime allocations in multi-hop Wi-Fi networks: A stability and convergence study with testbed evaluation

2019

Abstract REACT is a distributed resource allocation protocol used to negotiate a max–min allocation of airtime for multi-hop ad hoc wireless networks. Two approaches are proposed for a node to realize its REACT allocation in a contention-based MAC protocol. This is achieved by tuning its contention window to a value that corresponds to its allocation. Only a change in the allocation, due to a change in local traffic requirements or local network views, results in re-tuning. The approaches for tuning are implemented in commercial Wi-Fi devices and their stability and convergence are studied experimentally in the w-iLab.t wireless network testbed. These properties are also studied analyticall…

An energy analysis of IEEE 802.15.6 scheduled access modes

2010

Body Area Networks (BANs) are an emerging area of wireless personal communications. The IEEE 802.15.6 working group aims to develop a communications standard optimised for low power devices operating on, in or around the human body. IEEE 802.15.6 specifically targets low power medical application areas. The IEEE 802.15.6 draft defines two main channel access modes; contention based and contention free. This paper examines the energy lifetime performance of contention free access and in particular of periodic scheduled allocations. This paper presents an overview of the IEEE 802.15.6 and an analytical model for estimating the device lifetime. The analysis determines the maximum device lifeti…

Achieving Robustness through Caching and Retransmissions in IEEE 802.15.4-based WSNs

2007

This paper proposes a network-layer protocol for wireless sensor networks based on the IEEE 802.15.4 standard. Our protocol is devised to provide reliable data gathering in latency-constrained applications, and exploits both the flexibility of the IEEE 802.15.4 MAC layer and features of data aggregation techniques, such as implicit acknowledgment of reception. The proposed protocol acts as a routing module and a control entity for the MAC layer and provides reliable communication, while managing power saving and synchronizertion among nodes. Without relying on MAC-layer acknowledgments, the protocol implements caching and network-layer retransmissions, triggered upon detection of a link fai…

Object Matching in Distributed Video Surveillance Systems by LDA-Based Appearance Descriptors

2009

Establishing correspondences among object instances is still challenging in multi-camera surveillance systems, especially when the cameras’ fields of view are non-overlapping. Spatiotemporal constraints can help in solving the correspondence problem but still leave a wide margin of uncertainty. One way to reduce this uncertainty is to use ap- pearance information about the moving objects in the site. In this paper we present the preliminary results of a new method that can capture salient appearance characteristics at each camera node in the network. A Latent Dirichlet Allocation (LDA) model is created and maintained at each node in the camera network. Each object is encoded in terms of the…

Extracting Touristic Information from Online Image Collections

2012

In this paper, we present a Geographical Information Retrieval system, which aims to automatically extract and analyze touristic information from photos of online image collections (in our case of study Flickr). Our system collect all the photos, and the related information, that are associated to a specific city. We then use Google Maps service to geolocate the retrieved photos, and finally we analyze geo-referenced data to obtain our goals: 1) determining and locating the most interesting places of the city, i.e. the most visited locations, and 2) reconstructing touristic routes of the users visiting the city. Information is filtered by using a set of constraints, which we apply to select…

Entropy-based Localization of Textured Regions

2011

Appearance description is a relevant field in computer vision that enables object recognition in domains as re-identification, retrieval and classification. Important cues to describe appearance are colors and textures. However, in real cases, texture detection is challenging due to occlusions and to deformations of the clothing while person's pose changes. Moreover, in some cases, the processed images have a low resolution and methods at the state of the art for texture analysis are not appropriate. In this paper, we deal with the problem of localizing real textures for clothing description purposes, such as stripes and/or complex patterns. Our method uses the entropy of primitive distribu…

MANSIONI E DEROGABILITÁ INDIVIDUALE ASSISTITA

2018

Il saggio analizza l'istituto della derogabilità individuale assistita delle mansioni per come configurato dal d.lgs. 81/2015: tale norma, nel consentire accordi tra lavoratore e datore modificativi di mansioni, retribuzione, livello di inquadramento e categoria legale, depone a favore di una marcata liberalizzazione dell’oggetto del contratto di lavoro. I limiti dettati dalla legge – la stipula innanzi a delle sedi protette e il ricorrere di generiche finalità – contribuiscono a creare uno scenario "fluido" di tutela del lavoratore quale contraente debole, non soltanto all'atto della sottoscrizione del patto, ma anche in sede processuale. The essay focuses on the mechanism of the individua…