F. Attivissimo

Uncertainty Analysis in Photovoltaic Cell Parameter Estimation

This paper describes a theoretical approach to evaluate the uncertainty on the series and shunt resistances estimated by the seven-parameter (double diode) model of a photovoltaic (PV) cell using data commonly provided by panel manufacturers, measured environmental parameters, and semiempirical equations. After a brief survey on the state of the art and the treatment of the double-diode model, the procedure proposed by the authors, to estimate the unknown parameters, is illustrated. The theoretical expression of the uncertainty, which affects the estimation of the series and shunt resistances (namely, and ) of a PV cell, is then derived. A statistical analysis performed by means of a Monte Carlo simulation is in agreement with the theoretical expression of the uncertainty.

An acoustic method for soil moisture measurement

The paper deals with the problem of measuring the soil moisture by an accurate, in-situ, real-time method. Like this a mathematical model which describes a functional relationship between water content of agricultural soil and velocity of propagation of sound waves is analyzed in systematic way. After studying the conditions that guarantee the applicability of proposed model, the velocity curves relevant to different kinds of soils are determined. This model seems to be promising for moisture soil measurements in greenhouse where the soil characteristics are well known but further investigation are necessary.

Calibration of an Inspection System for Online Quality Control of Satin Glass

In this paper, a prototype system that is able to reproduce all the functionalities of an automatic glass inspection system is presented. The proposed quality inspection system assures several advantages with respect to the human-made inspection, such as objectivity and accuracy, and it is attractive for small enterprises with respect to commercial vision systems because it guarantees good results and considerable reliability with low incidence on manufacturing costs. In particular, it was proposed in this paper a method, based on morphological operations, for registering the acquisition system, which is composed of several cameras that acquire different partial images of the entire glass sheet moving on a conveyor. A method for digitally correcting the nonuniformities of the lighting system is also discussed; it is based on a least squares spline approximation of the intensity profile. The presented methods are rather general and can be applied to the calibration of image acquisition systems in other application fields.

A tool for Photovoltaic panels modeling and testing

This paper presents the results obtained testing a tool designed to characterize and simulate the behavior of a Photovoltaic (PV) panel under real and/or simulated working conditions. The presented tool permits the continuous monitoring of the I-V (Current-Voltage) and P-V (Power-Voltage) characteristics of the panel and the comparison between actual and expected performance; in this way it is possible to prevent any possible decrease of the output power and to replace the monitored module before it goes out of order or its efficiency falls under a given threshold.

Characterization of a system for measurements on soft ferrites

This paper deals with the characterization of a system for measurements on soft ferrites through a volt-amperometric method. The accurate control of the driving input field is discussed as a critical aspect for the definition of the correct operating conditions on the magnetic sample. A custom-built transimpedance amplifier is characterized in terms of total harmonic distortion and signal-to-noise and distortion ratio of the primary current and shown as a valid configuration for the required purposes. As a main contribution, the uncertainty analyses of the major loop measurement and of the magnetic accommodation measurement of minor asymmetric loops are provided.

Denoising filter to improve the quality of CT images

The purpose of this study is to assess the effect of different noise reduction filters on computed tomography (CT) images. In particular, a denoising filter based on a combination of Gaussian and Prewitt operators is proposed. Simulation results show that the technique proposed increases the image quality, and then allows using low radiation dose protocol in CT examinations. This work was carried out in collaboration with G.Moscati Hospital of Taranto (Italy), that supplied all the images and technical materials used in the proposed algorithm.

Design and Development of a sensor prototype for Soil Moisture Measurement: First Experimental Results

In this paper the design and the development of an innovative soil moisture sensor for agricultural applications is presented; also the first experimental results are illustrated and compared with those deriving by the underlying theory. The basic idea is to excite the soil with seismic waves (both compressional and shear ones) and to measure their velocity of propagation using a transmitter and a receiver that are separated by a known distance. The first encouraging experimental results here presented are obtained using the cross-correlation between the transmitted and the received signal; however repeated measures show a troublesome scattering around the theoretical values. In depth analysis has shown that this scattering is mainly due to the presence of interfering background noise; the authors are currently working to improve the experimental setup to guarantee better results.

Best matches procedure in transition phase identification for hand grip test analysis in normal and pathological subjects

In this paper, the analysis of biomedical data characterizing motor activities of the limbs is carried out with the aim of extracting useful information for evaluating the state of subjects affected by Parkinsons disease. Initially, a simple and inexpensive system that measures the force of the palmar grip has been presented; then, a suitable software protocol that is able to record, manage, and interpret the acquired data has been realized. Afterward, a first analysis in the time domain has led to the identification of some biomedical parameters characterizing motor activities of the limbs; the study of these parameters and the analysis of the correlations between the acquired data have permitted the development of suitable models describing the time behavior of the palmar grip. In this paper, the authors propose a more detailed study that evaluates the filtering, phase noise effects, and performance of different methods used to estimate the characteristic parameters of the palmar grip.

Wavelet based methods for speckle reduction in ultrasound images

The purpose of this study is to assess the effect of different noise reduction filters on ultrasound images. In particular two denoising filters based on thresholding and wavelet coefficients are proposed. Simulation results show that the techniques developed increase the image quality and then allow a more accurate diagnosis.

Image quality evaluation of breast tomosynthesis

Digital breast tomosynthesis provides significant opportunities in both diagnostic and cancer screening. It gives high quality image and overcomes some inherent limitations of the traditional 2D digital mammography due to tissues overlapping which makes difficult to detect cancers. Unfortunately, the quality of tomographic images is directly related to the radiation dose on the patient and it is significantly affected by the parameters set by the technician during the mammographic exam. Normally, breast tomosynthesis provides a little increase in radiation dose with respect 2D mammography. The aim of this study is to investigate the relation between the radiation dose on the patient and the resulting image quality, by comparing the tomosynthesis performance with the 2D digital mammography.