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**Renzo PerfettiZanichelli, 2013**

La seconda edizione di Circuiti elettrici mantiene la collaudata impostazione basata su una graduale esposizione della teoria, con particolare attenzione alle tecniche di risoluzione dei problemi, descritte in forma algoritmica e illustrate attraverso numerosi esempi svolti. Alcuni argomenti sono presentati secondo un nuovo ordine, più funzionale alle esigenze didattiche. Molti esempi sono stati aggiornati.

Sito web del libro:

http://www.zanichelli.it/ricerca/prodotti/9788808178886/renzo-perfetti/circuiti-elettrici/

**Recurrent neural network for approximate nonnegative matrix factorization ****Giovanni Costantini, Renzo Perfetti, Massimiliano Todisco**

A recurrent neural network solving the approximate nonnegative matrix factorization (NMF) problem is presented in this paper. The proposed network is based on the Lagrangian approach, and exploits a partial dual method in order to limit the number of dual variables. Sparsity constraints on basis or activation matrices are included by adding a weighted sum of constraint functions to the least squares reconstruction error. However, the corresponding Lagrange multipliers are computed by the network dynamics itself, avoiding empirical tuning or a validation process. It is proved that local solutions of the NMF optimization problem correspond to as many stable steady-state points of the network dynamics. The validity of the proposed approach is verified through several simulation examples concerning both synthetic and real-world datasets for feature extraction and clustering applications.

To be published in Neurocomputing (2014)

Elisa Ricci Renzo Perfetti

IEEE Transactions on Medical Imaging vol. 26, N. 10, 2007

**SINGLE-SIDED OBJECTIVE SPEECH INTELLIGIBILITY ASSESSMENT BASED ON SPARSE SIGNAL REPRESENTATION**

2012 IEEE INTERNATIONAL WORKSHOP ON MACHINE LEARNING FOR SIGNAL PROCESSING, SEPT. 23–26, 2012, SANTANDER, SPAIN

Transcription of speech signals, originating from a

lawful interception, is particularly important in the forensic

phonetics framework. These signals are often degraded and

the transcript may not replicate what was actually

pronounced. In the absence of the clean signal, the only way

to estimate the level of accuracy that can be obtained in the

transcription is to develop an objective methodology for

intelligibility measurements. In this paper a method based

on the Normalized Spectrum Envelope (NSE) and Sparse

Non-negative Matrix Factorization (SNMF) is proposed to

evaluate the signal intelligibility. The approaches are tested

with three different noise types and the results are compared

with the speech intelligibility scores measured by subjective

tests. The results of the experiments show a high correlation

between objective measurements and subjective evaluations.

Therefore, the proposed methodology can be successfully

used in order to establish whether a given intercepted signal

can be transcribed with sufficient reliability.

E. Cardelli, A. Faba, N. Palotti, M. Pompei and F. Tissi - INTERMAG 2012, 7-11 May, Vancouver.

Abstract - This paper deals with the design and the experimental verification of two distinct magnetic field exposure systems for applications related respectively to the in vivo and the in vitro analysis of the magnetic field effects at extremely low frequency ELF. The performances of the two systems in exposure uniformity, magnetic induction and frequency range are discussed in the paper, and verified with a dedicated series of experimental tests. Finally some information about the level of temperature and vibration increase expected and their control are given, in order to show the capability of the exposure systems presented to be efficient tools for magnetic ELF exposure studies not affected by typical artifacts produced by this kind of mechanical parasitic effects.

]]>The CEM laboratory is part of the "University of Perugia - Polo Scientifico e Didattico di Terni". The activities are focused on electromagnetic compatibility, electrical safety, electromagnetic nondestructive testing and magnetic materials.

More information at http://laboratoriocem.tr.unipg.it/index.htm

]]>More information at http://laboratoriocem.tr.unipg.it/index.htm

E. Cardelli, A. Faba, " A Benchmark Problem of Vector Magnetic Hysteresis for Numerical Models", IEEE Transactions on Magnetics, VOL. 50, NO. 2, February 2014, ISSN: 0018-9464.

Abstract - In this paper we present a benchmark problem for the validation of numerical models of vector magnetic hysteresis. The problem geometry and the measurement system are described. The materials considered are both oriented grain OG and not oriented grain NOG Si-Fe steels. A series of experimental data about magnetic field and magnetic induction loci under rotational magnetization are presented with the corresponding magnetic losses. The measured data can be useful as a reference for the numerical models testing, comparison and development. In addition, we propose here a comparison of the experimental data with the numerical results computed using a vector hysteresis model based on the extension of the Preisach model in 2-d.

A presentation of this work is in the attachment file.]]>