Search results for " Local"

Quantifying the trade-off between useful and parasitic absorption of light for plasmonic light trapping in thin silicon films

2016

We apply a combination of photocurrent and photothermal spectroscopic techniques to experimentally quantify the trade-off between useful and parasitic absorption of light in thin hydrogenated microcrystalline silicon (?c-Si:H) films incorporating self-assembled silver nanoparticle arrays, located at the rear side, for improved light trapping via resonant plasmonic scattering. The photothermal technique is used to measure the total absorptance while the photocurrent spectroscopy accounts only for the photons absorbed in the ?c-Si:H layer (useful absorptance); therefore, the method allows for independent quantification of the useful and parasitic absorptance of the plasmonic (or any other) li…

Revealing Transmit Diversity Mechanisms in Commercial IEEE 802.11 Cards

2008

Service differentiation in WLAN has been traditionally faced at the MAC layer. However, some PHY layer parameters, such as the transmission power, the antenna, and the modulation/coding scheme, have a deep impact on network performance. Since the criterion for selecting these parameters is left to the vendor specific implementations, the performance spread of most experimental results about 802.11 WLAN could be affected by vendor proprietary schemes. The focus of this paper is an experimental analysis of the undisclosed antenna diversity mechanisms employed by some widely used cards (namely, the Atheros and Intel based cards), and a thorough understanding of the optimization goals which gui…

INDOOR LOCALIZATION USING COGNITIVE RADIOS AND SOFTWARE-DEFINED WIRELESS NETWORKS

WMPS: A Positioning System for Localizing Legacy 802.11 Devices

2012

The huge success of location-aware applications calls for the quick development of a positioning system alternative to GPS for indoor localization based on existing technologies such as 802.11 wireless networks. In this paper we propose WMPS, the Wireless MAC Processor Positioning System, that is a localization system running on off-the-shelf 802.11 Access Points and based on time-of-flight ranging of users’ standard terminals. We prove through extensive experiments that propagation delays can be measured with the accuracy required by indoor applications despite the different noise components that can affect the result, like latencies of the hardware transreceivers, multi- path, ACK jitters…

A machine learning approach for user localization exploiting connectivity data

2016

The growing popularity of Location-Based Services (LBSs) has boosted research on cheaper and more pervasive localization systems, typically relying on such monitoring equipment as Wireless Sensor Networks (WSNs), which allow to re-use the same instrumentation both for monitoring and for localization without requiring lengthy off-line training. This work addresses the localization problem, exploiting knowledge acquired in sample environments, and extensible to areas not considered in advance. Localization is turned into a learning problem, solved by a statistical algorithm. Additionally, parameter tuning is fully automated thanks to its formulation as an optimization problem based only on co…

An evaluation of recent local image descriptors for real-world applications of image matching

2019

This paper discusses and compares the best and most recent local descriptors, evaluating them on increasingly complex image matching tasks, encompassing planar and non-planar scenarios under severe viewpoint changes. This evaluation, aimed at assessing descriptor suitability for real-world applications, leverages the concept of approximated overlap error as a means to naturally extend to non-planar scenes the standard metric used for planar scenes. According to the evaluation results, most descriptors exhibit a gradual performance degradation in the transition from planar to non-planar scenes. The best descriptors are those capable of capturing well not only the local image context, but als…

Text localization from photos

2009

In this paper a new text extraction algorithm is proposed. In real scenes the text is usually overlapped or is part of the background. To identify the text regions, in complex conditions, a method exploiting a “multi-resolution feature based method” for extracting text with undefined dimension has been developed. Once identified, the multi-resolution information are merged and skimmed through a set of Support Vector Machines (SVM). The tests and the comparisons with other techniques, performed on heterogeneous images, have shown the effectiveness of the proposed.

Politica e amministrazione nel sistema delle autonomie territoriali: merito e fiducia a trent’anni dalla privatizzazione

2022

il saggio analizza la disciplina dei rapporti tra organi di indirizzo politico e dirigenza amministrativa nel sistema delle autonomie territoriali.

sub artt. 90, 91, 92, 93, 94, 95, 96, 107, 109, 110, 111 d.lgs. n. 267/2000

2009

I saggi analizzano la disciplina del rapporto di lavoro alle dipendenze degli enti locali alla luce della dlgs. n. 267/2000. Particolare atenzione è dedicata al raffronto tra la disciplina del lavoro pubblico statale e quello alle dipendenze degli enti locali, al fine di segnalare discontinuità e interdipendenze.

Norme per gli enti territoriali e il servizio sanitario nazionale

2013

Il saggio analizza le norme dedicate a enti locali e SSN nella riforma Brunetta The essay analyses norms on local administrations and National Health Service in Brunetta reform