Andrea Zanobini

Automatic-test equipment for the characterization of aluminum electrolytic capacitors

This paper describes the most important factors influencing the aluminum electrolyte capacitor showing, in particular, the effect of temperature on the lifetime of this device. The automation of the measurement system, with the oven interfaced with a PC, was also completed to control all the involved parameters.

The evaluation of the combined standard uncertainty for nonlinear models

In this work, the law of propagation of uncertainty is studied for complex system with nonlinear properties. Sensitivity analysis is carried out using the Taylors series expansion of higher-order terms than the usual one presented in the ISO (GUM). An experimental problem is considered to verify the obtained theoretical results and to asses the validity of the implemented formulation.

The Principle of Maximum Entropy Applied in the Evaluation of the Measurement Uncertainty

The maximum entropy approach is a flexible and powerful tool for assigning a probability distribution to a measurable quantity treated as a random variable, subjected to known moment constraints. The aim of this paper is to describe how the principle of maximum entropy may be used to transform information about the value of a quantity into a probability density function reflecting exactly that information and nothing more. The principle will be applied to common cases of metrological interest, where different kinds of information are available. The derivation of the probability density function is given in each case and numerical results are reported to demonstrate the efficiency of the method

Measurement uncertainty in a multivariate model: A novel approach

The confidence region and the related confidence level are the bases for the uncertainty expression in a measurement process. In this work a multivariate model is considered and different situations with respect the parameters constituting the model are examined. Computational results are reported and analysed to asses the validity of the proposed approach.

Evaluation of measurement uncertainty by Bayesian-entropic approach

This paper discusses the possibility of using Bayesian inference methods and entropy optimization principles for the evaluation of uncertainty in a measurement process. In particular, the proposed approach is applied to the recalibration of a measurement device which incorporates a calibrated reference quantity. An a priori estimate and an uncertainty for the reference quantity are supposed to be available from a previous calibration. The adopted method is shown to produce a posteriori estimates for the reference quantity, regarded as the recalibrated value and for the measurand which are correlated.

Qualification tests and reliability analysis on electronic ballast system

The paper presents results obtained by qualification tests implemented on an electronic ballast, with particular attention to ON/OFF and thermal tests and EMC tests. Being the device under test an innovative electronic power supply system designed for application in energy saving, its fundamental also an evaluation and analysis of the reliability performances. To this aim some results obtained with reliability prediction method are also presented in the paper.

Generalized distribution-free bound on the level of confidence in the result of a multivariate measurement process

The confidence region and the related confidence level ore the bases for the uncertainty expression in a multivariate measurement process. The Guide [l] ,gives an extended discussion of the problem of establishing the relation between the confidence interval and the related confidence level, which depend on the probability distribution associated with ones knowledge of the measurand. In this work a generalized distribution free bound on the level of confidence in the result of a measurement performed in a multivariate model-process is presented. The bound is based on the generalization of the second order Markov inequality. Kewords Confidence region-level of confidenceMarkov inequality.

A drone anti-collision system: Maintaining a fixed distance from a target during the flight

The purpose of this paper is the metrological characterization of the infrared distance sensor Teraranger One, developed and built by Terabee HQ, located in Saint Genis Poully, near Geneve. The purpose of this project is to give to the aircraft a frontal anticollision system based on the sensor in question, with the additional functionality of maintaining a fixed distance from the detected target. The control of the position in the frontal direction is maintained through maneuvers of pitch, which alter the relative height of the nose and the rear of the aircraft, allowing the latter to advance or retreat. The controls roll, yaw and throttle are not affected by this movement. Therefore, to obtain the control using a distance sensor it is sufficient that the latter is introduced in the control chain of the only pitch channel. In this way, the other controls will still be used, and their operation will be unaffected. It will therefore be possible to move the drone along a wall maintaining a fixed distance from it, with useful applications in isometric imaging or the use of drones for inspection.

Measurements and characterization of air temperature sensors for weather stations

Weather monitoring has become extremely important with numerous applications in agriculture, military operations, civil transportation and to avoid natural disasters. For this reason there is an increasing number of measurement stations and their performances, with particular attention to the sensors section, have to be verified before their application on the field. A typical weather station uses multiple sensors to monitor relative humidity, temperature and so on. In particular, in this paper two different types of temperature sensors will be tested: a glass-coated PT100 class A 4-wire air temperature sensor and a combined temperature/humidity sensor. This work aims to compare these two sensors under variable weather conditions by a specific testing activity in order to evaluate their performance also in a real installation.

Bayesian statistics for conformity assessment

This paper discusses the opportunity to use the Bayesian inference methods to evaluate the uncertainty of measurement in the conformity assessment. In a small practical example the approach is applied to the conductivity measurement of a rubber insulating. The adopted method is shown to produce a posterior estimates to test a hypothesis with a significance level.