A. Di Nisio

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.

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.

Improved Static Testing of A/D Converters for DC Measurements

A new method is presented for the calibration and the linearity testing of analog-to-digital converters (ADCs) and dc digital instruments, such as digital voltmeters (DVMs). The test is truly static, because it uses only dc voltages with a small superimposed noise (dithering). It is much faster than that described in the IEEE Standard 1057/94 since it uses a minimal number of test signals and acquired samples in a theoretically nearly optimal manner, i.e., maximum-likelihood estimation. In addition, contrary to the test described in the IEEE Standard 1241/00, it allows offline measurements and testing of stand-alone instruments, such as DVMs. Another advantage of the proposed method is that the resolution requirements for the source of test signals are relaxed. After a review of the state of the art, this paper provides the mathematical derivation of the employed estimator. Simulations, theoretical analyses, and experimental results are also provided to illustrate the performances of the proposed test method.

Analysis of the uncertainty of the double-diode model of a photovoltaic panel

In this paper the theoretical expression of the uncertainty, which affects the estimation of the series and shunt resistances (namely Rs and Rsh) of a Photovoltaic cell, is derived. After a brief treatment about the double diode model, the new procedure to estimate the unknown parameters proposed by the authors is illustrated. Numerical results and a first discussion about the biases and standard deviations of Rs and Rsh estimators in a wide range of environmental conditions are given.

Design of a low cost multipurpose wireless sensor network

This paper proposes the implementation of a low-cost and reliable multipurpose wireless sensor network framework. It has been designed to be easily customizable in order to adapt it to the particular application.

A proposal for an open source energy meter

This paper describes the design and the implementation of a prototype for an Alternating Current (AC) energy monitoring device based on an open source concept. The measurement device aims to provide a remote monitoring interface useful for three-phase and single-phase AC power systems. The open-source philosophy has been adopted designing the software components in order to make all features easily customizable by the user. In this way one can easily develop new applications making cost- and time-effective the migration to future smart grid infrastructures.

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.

Validation of a Photovoltaic electrical model against experimental data

This paper deals with a Photovoltaic (PV) plants characterization technique based on the estimation of the electrical parameters of the double-diode equivalent circuit of each module. This effort was intended to predict the performance indexes of different photovoltaic technologies. The objectives of this work is to implement the methodology at the Photo Voltaic LABoratory (PV-LAB) to collect and analyze module performance data and to validate the electrical model by comparing the modeled I-V characteristics on the experimentally obtained data sets.

Measuring Dynamic Nonlinearity of Digitizers Affected by Time Base Distortion

Dynamic nonlinearity is a well-known major source of signal corruption in digital scopes and A/D conversion channels in general, particularly when dealing with fast signals and high sampling rates. This paper shows that the dynamic nonlinearity cannot be correctly measured without taking into account the systematic errors affecting the sampling instants (time base distortion) and presents two methods (nonparametric and parametric) to obtain accurate measurements in the presence of such errors. Both simulations and experimental results are provided to illustrate the problems arising with traditional methodologies and the accuracy of the proposed one.

Measuring Dynamic Nonlinearity in High-Speed Digital Scopes

The paper presents two methods (nonparametric and parametric) to measure the nonlinearity in presence of time base distortion, as usually happens in high-speed digitizers. Both simulation and experimental results are provided to illustrate the problems arising with traditional methodologies, and the accuracy of the proposed ones.