CRENNA F.

The probabilistic modelling of measurement systems is discussed, showing how it provides a practical and effective way for addressing uncertainty evaluation, that does not require any commitment to specific philosophical schools, such as the frequentistic and the Bayesian ones. Firstly, different ways of modelling the same measuring device are...

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Systematic dynamic effects in linear measuring devices include possible amplification or attenuation, and phase shift of the spectral components of the indicated signal in respect to the original phenomenon. When this effect is non negligible, dynamic compensation should be applied. Yet in any case uncertainty on the modulus and the phase of...

An important task in biomechanics is human body articulations' internal torques measurement. This is known as a kinetic or inverse-dynamics problem. Its solution requires a combination of kinematic and dynamic measurements with a biomechanical model, involving subject-related anthropometric parameters. The uncertainty-evaluation thereof is here...

Biomechanical analysis of human movement is based on dynamic measurements of refer-ence points on the subject's body and orientation measurements of body segments. Collected data include positions' measurement, in a three-dimensional space. Signal enhancement by proper filtering is often recommended. Velocity and acceleration signal must be...

This paper deals with the spectral estimation of sea wave elevation time series by means of ARMA models. To start, the procedure to estimate the ARMA coefficients, based on the use of the Prony's method applied to the auto-covariance series, is presented. Afterwards, an analysis on how the parameters involved in the ARMA reconstruction...

The paper focuses on the tuning of Auto Regressive Moving Average (ARMA) models aimed at describing the spectral behaviour of sea wave elevation time series. The analysis considers mono-modal sea states, mainly due to the wind effect. The main problem related to the estimation of such models, starting from the wave elevation time series,...

The evaluation of the uncertainty due to systematic dynamic effects is addressed. When high dynamic performance is required, they should be compensated, by solving the associated inverse dynamic problem. When instead they are considered compatible with the target uncertainty, they may be simply included in the uncertainty budget. Furthermore,...

The approval of the European Measuring Instrument Directive on April 2004 renews completely the legal metrology sector, proposing a "new approach" aiming to technical normalization and harmonization and toward a "global approach" to evaluation and conformity. According to the principles of the "new approach" regulatory model, the Directive...

The problem of the nature of probability has been drawn to the attention of the measurement community in the comparison between the frequentist and the Bayesian views, in the expression and the evaluation of measurement uncertainty. In this regard, it is here suggested that probability can be interpreted as a logic for developing models of...

Information technology and distribution instrumentation, supporting the monitoring of dynamical processes, deserve careful consideration to exploit their ability of providing "measurements" with acknowledged metrological consistency. The paper discusses the conceptual background for characterizing vibrating systems through standardized...

The monitoring of sea state conditions, either for weather forecasting or ship seakeeping analysis, requires the reliable assessment of the sea spectra encountered by the ship, either as a final result or intermediate step for the measurement of the relevant wave-motion parameters. In current analyses, different spectrum estimation methods,...

The monitoring of sea waves, either for weather forecasting or for comfort evaluation in navigation, typically includes spectrum measurement of wave elevation, either as the final result or as an intermediate step for the measurement of the relevant wave-motion parameters. Therefore, different spectrum estimation methods have been compared, by...

Remote sensing, implemented through virtual instrumentation, is a very important technology for industrial measurements. Moreover, the architecture and methods involved are effective for the teaching and dissemination of measurement technologies. A proper design may yield to cost-effectiveness, reliability and flexibility. Despite that, some...

The reliable monitoring of sea state parameters is a key factor for weather forecasting, as well as for ensuring the safety and navigation of ships. In the current analysis, two spectrum estimation techniques, based on the Welch and Thomson methods, were applied to a set of random wave signals generated from a theoretical wave spectrum obtained...