Francesco Adamo

This paper deals with the problem of measuring the moisture of agricultural soils by an accurate theoretical method valid for different kinds of soils in different physical conditions. In this work we propose a theoretical analysis based on the propagation of seismic waves in a complex medium as the agricultural soil is. Particularly we prove that the use of both compressional and shear waves simplifies the analysis (by reducing the number of parameters affecting the moisture measurement) and increases the accuracy of the assessment without increasing the computational charge. Moreover we have noticed that, to obtain a complete and accurate mathematical model, it is necessary to focus on the Z factor, which accounts for the influence of air and water content in the soil on the sound velocities. The aim is to demonstrate that velocity of propagation of compressional and shear waves are influenced differently for the different physical factors. Moreover, we will show that the Z factor has to be taken into account for this different dependence on parameters and microclimatic characteristics of the soil

Dithering is a useful technique that removes quantization error and part of the linearity error in A/D converters. Removing the remaining static error requires a periodical fast measurement of the characteristic, which is a rather difficult task because of the intrinsic very high ...

In this paper the design and the development of a moisture sensor for granular and porous mediums are presented. In the proposed method the moisture is measured by estimating the velocity of propagation of seismic waves (both compressional and shear ones) between a transmitter and a receiver separated by a known distance. The first experimental results are illustrated and compared with theoretical results.

This paper presents the application of a measurement procedure for improving data acquisition for the characterization of soft magnetic ferrites. The approach is based on a voltamperometric technique and is aimed at better measure minor asymmetric cycles improving the quality and resolution of measurement data. Physical and mathematical conditions require the use of current and voltage signals with very different dynamic range since the major loop has to be traced together to the minor cycles. In such a way, the possibility to get the signal via two channels with different configuration is analyzed and discussed. Preliminary results are reported in the paper together to some preliminary concerns relevant to the metrological characterization of the method.

This paper presents the evaluation of the performance, in terms of uncertainty, of a tool designed to estimate the main parameters of a model of a photovoltaic panel (PVP) under real and/or simulated working conditions. The presented tool permits the characterization of the panel, and it is useful to predict its behavior in whatever working condition; in this way, it is possible to compare the actual and expected performance to prevent any decrease in the output power, so permitting the replacement of the monitored module before it goes out of order or its efficiency falls under a given threshold. The well-known two-diode model is used to estimate the parameters of the electrical equivalent circuit of the PVP and to simulate the I -V and P-V characteristic curves in any given environmental condition of irradiance and/or temperature. The model and the estimation algorithm are implemented with MATLAB functions, whereas data acquisition and result presentation are managed by a LabVIEW graphics user interface. The presented tool has been validated against an experimentally characterized PVP. The environmental parameters of the model such as irradiance and temperature have been set (with their respective uncertainties) during simulations or directly measured during the outdoor tests, whereas the others parameters have been evaluated using a best-fit algorithm on the measured data. The estimation is based on the minimization of a new objective function and on a modified expression of the model resistances, which differ from those mentioned in the available literature. After a review of the state of the art, this paper provides the description of the estimation technique and its validation by means of simulations and experiments. Some results are also provided to illustrate the performance of the proposed test method.

Today, quality control is a nodal point in many industries, and in the glass one in particular; in most cases the human control does not catch up with the pressing market requirements, therefore computer vision inspection systems are preferable to reduce costs and to improve the product quality, but several problems must be solved. In this paper a prototype system, able to reproduce all the functionalities of an automatic glass inspection system, is designed and realized; it guarantees good results and considerable reliability with low incidence on manufacturing costs. The final in-line computer vision system is under development in cooperation with a specialized electronic industry.

Undoubtedly voltage and current measurements under distorted conditions have recently gained more and more importance in the actual electric market; the deregulation acting in this field with the consequential liberalization and the augmented request of monitoring capabilities on the power quality from the power suppliers, is at the origin of an increased demand of measurement instruments of the various electric parameters with increased capabilities (greater precision, versatility, etc.), less expensive and with interfacing capabilities to permit their use in automatic measurement system. In this paper we expose the first results of an experimental research activity currently in progress at Polytechnic of Bari, aiming at the design and realization of testing equipment that is cheap, simple to use and accurate.

... I. Kale is with the Applied DSP and Very Large Scale Integration Research Group, Department of Electronics Systems, University of Westminster, W1W 6UW London, UK (e-mail: kalei@westminster.ac.uk). Digital Object Identifier 10.1109/TIM.2007.894893 ...

The main purpose of the present work is to design and build a prototype system based on seismic sensors for the measurement of the degree of saturation in unconsolidated granular mediums. In previous papers (F. Adamo et al., 2004), (F. Adamo et al., 2006) the authors have described the theoretical analysis necessary to estimate the degree of soil saturation which is obtained by measuring the propagation velocities of both compressional and shear seismic waves. The knowledge of a general mathematical model based on theories of propagation of elastic waves has enabled the development of a first prototype of the system. The more in depth analysis of the first experimental results (F. Adamo et al., 2007) has highlighted the validity of the theoretical model but has also revealed some limits of the previously designed hardware. Considering these limits, the authors have developed an improved system based on very cheap tri-axial accelerometers: this prototype assesses the moisture in the soil with an acceptable measurement uncertainty. In this paper major emphasis is given to the description of the custom-built hardware and to the measurement method. This paper is arranged in three different sections: in the first section we present the mathematical model resume, in the second one we describe the last prototype developed to improve the performances of the measurement system in terms of measurement uncertainty, reliability and noise immunity: in the third section we characterize the measurement technique and the experimental setup.

The paper discusses the problem of measuring the dynamic systematic error, or the dynamic input-output characteristic, of an analog-to-digital converter simulated by a sinusoidal input. First of all, it is shown that the statistical methods, although widely used , yield misleading results in dynamic conditions, i.e., when the converter characteristics presents hysteresis. Secondly, the paper presents a modified version of a frequency-domain method (Chebyshev test), previously developed by the authors for testing static devices. Both simulation and experimental results show that the Chebyshev test for dynamic nonlinearities is a very fast way to measure the input-output characteristic of an ADC affected by hysteresis error.

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

This work gives a detailed description of some laboratory practices about SCADA/HMI systems developed for didactic purposes for various undergraduate courses at the 1st Engineering Faculty of Polytechnic of Bari, Department of Electrics and Electronics (Italy); they consider the use of National Instruments LabVIEWreg with the associated data logging and supervisory control toolset (DSCreg) to develop the SCADA/HMI portion (operator's interface and data logging) of a software simulated industrial plant consisting of a vessel with charge and discharge proportional valves, a heating/cooling element, a level sensor and two flow rate sensors. The control of this plant can be done in two different ways, according to the difficulty level of the practice: by way of a LabVIEW VI or by way of a ladder program written with RSLogix 5/500 and emulated by RSLogix Emulate 5/500 (both are Rockwell Software's products, the first being the ladder software development environment for PLC-5/SLC500 family of industrial programmable logic controllers (PLCs) from Allen Bradley and the second being the related software emulator)

ABSTRACT 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.

In the paper a new frequency-domain approach to measure and correct the static nonlinearity error of A/D converters is analyzed. The nonlinearity is (i) measured as a linear combination of Chebyshev polynomial, whose coefficients are derived via frequency-domain analysis, and (ii) corrected with a nonlinear equation solving method, which makes use of the parametric form of the static characteristic. The proposed methodology is especially suited for dithered converters, due to their particular features of smoother nonlinearity and very high resolution. Both simulation and experimental results are reported, quantifying also the achieved increase of effective bits.

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.

ABSTRACT 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.