IMEKO Event Proceedings Search

Page 807 of 936 Results 8061 - 8070 of 9356

Salvatore Nuccio, Ciro Spataro, Giovanni Tinè
A procedure to evaluate the electromagnetic immunity degree of a data acquisition system

The paper deals with the empirical evaluation of the electromagnetic immunity degree of PC-based data acquisition systems. A first series of experiments is carried out subjecting the systems to known and standardized disturbances in order to check if and how their performances are corrupted. A second series of experiments is performed in locations where unknown electromagnetic disturbances are present with the aim to find a method for the evaluation of the actual effect of the disturbances. By means of the proposed approach, when a data acquisition system is used to perform a measurement, it is possible to decide if the actual measurement conditions are adequate for the measurement targets. In some cases, moreover, the procedure allows the implementation of algorithms to compensate for the disturbance effects.

Ciro Spataro
The PUMA method applied to the measures carried out by using a PC-based measurement instrument

The paper deals with the uncertainty management in the measurements performed by using a generic PC-based measurement instrument. To accomplish the task, the uncertainty estimation is performed by using the PUMA (Procedure for Uncertainty MAnagement) method, which is an iterative technique completely based on the “Guide to the Expression of Uncertainty in Measurement” rules, but which offers a more engineering methodology. With this approach, it is possible to optimize the cost of the measurements versus the uncertainty target, avoiding the use of inadequate or, on the contrary, too expensive instrumentation. According to the PUMA method, in the paper different approaches to evaluate the uncertainties are presented, starting from the more precise methodologies and keeping on with the coarser, but quicker and cheaper ones.

Antonio Delle Femine, Carmine Landi, Mario Luiso
A Fully Automated Measuring Station for the Calibration of Voltage Transducers

Power quality analyses in the last years has assumed more and more heaviness in industrial environments, due to the presence of non-linear loads: they require suitable and precise measuring instrumentation. Nevertheless, while there are lots of power quality standards fixing high frequency limits for harmonic analyses, there is a lack of standards concerning transducers calibration at amplitude and frequency different from the rated ones. Therefore in this paper a fully automated measuring station for the calibration of voltage transducers in wide amplitude and frequency ranges is discussed. As an application, the results of the calibration of a commercial transducer are presented: they are used to implement a time-domain procedure for real-time correction of the frequency response of the calibrated transducer.

Petruta Mihai, Mihaela Matei, Mihai O. Popescu
The extrapolative methods principle for the forecast of the electrical energy consumption

As part of this paper, the main purpose is to present the elaboration methodology of some forecasts in the energy consumptions area, using few mathematical models. It is self-understood that are processes which are developed in time, in conditions of aleatory perturbation. The adaptation process must be continuous, showed in forecasts and rehearses castigations which will mentain the evolution on the target. More, once we are close to the specific targets, in the future are new targets, who presumes new forecast horizons and new decisions.

Milos Sedlacek, Ondrej Tomiska
Upgrading E-learning of basic measurement algorithms based on DSP and MATLAB Web Server

The paper presents an upgraded version of an application of MATLAB web server, one of MATLAB toolboxes, for teaching/learning some selected measurement algorithms important in processing discrete-time signals in measurement. The original version is described in [1] and [2]. The topics included are DFT/FFT (demonstration of DFT basic properties and DFT application in spectrum analysis and detection of week tones close to a strong tone), FIR filters (including the important moving average filter), basic IIR filters and some basics of stochastic signal processing in time domain and amplitude domain including finding SNR using correlation analysis. This upgraded version of MATLAB web server application is currently replacing an old one in teaching signal processing at Department of Measurement of the CTU in Prague, Faculty of Electrical Engineering, for both the students studying in Czech and (mostly Erasmus students) in English.

Martin Novotny, Milos Sedlacek
To the uncertainty of DFT-based DSP algorithms used for processing multifrequency signals

The paper analyses effect of windowing a multi-frequency signal on the result of calculating signal parameters based on DFT. Influence of window side-lobes of nearby harmonic signals on the result of computation depends on the on the used window and on the difference in the two components magnitudes and frequencies. There are several other sources of resulting bias and uncertainty of measurements based on such algorithms. These influences are also briefly mentioned. The presented examples concern two methods of estimating RMS value, but the described principle is applicable to all algorithms based on DFT. Both theoretical relations and simulation results are included.

Grzegorz Lentka, Jerzy Hoja
Fast impedance measurement method using Laplace transformation

The paper presents the impedance measurement method using a real-life step pulse as a perturbation signal and Laplace transformation as a tool for analyzing the response of the object under test. The method is addressed to explore different technical object (like anticorrosion coatings, gas sensors, ceramics, dielectrics biological tissues etc.) when the measurement time cannot be long. The presented method is known, but is not very popular because of some limitation. The paper presents the influence of the limitations on the accuracy of the equivalent circuit parameters identification.

Septimiu Crisan, Ioan Gavril Tarnovan, Titus Eduard Crisan
Vein pattern recognition. Image enhancement and feature extraction algorithms

Vein pattern recognition is one of the newest biometric techniques researched today. While the concept behind the method is quite simple, there are various challenges to be found throughout the design and implementation of a vein scanning device concerning the hardware lighting system and the actual algorithms used for processing the acquired images. In order to keep the scanning errors to a minimum the image acquired from the camera should be almost noiseless and the algorithms should be able to detect the vein pattern in various real life conditions. Many implementations of this method are now in a commercial phase and there is a great need for a system that can detect, analyze and extract the correct human vein pattern while keeping a low cost and reducing the computational needs of the image processing algorithms. This paper will offer some hardware implementation solutions based on our research and different algorithms will be discussed.

Ioan Gavril Tarnovan, Bogdan Tebrean, Titus Eduard Crisan
Shock Transducer with Hall Sensing Element

The aim of this paper is to show a determination method for mechanical shocks, using as sensing element an analogical Hall effect transducer. In the first part of the paper there will be enunciated the used physical principle, mentioning the conservation laws of mechanical energy and in following part we will describe the experimental setups and the behavior of the implemented captors. We will also analyze the factors that can generate errors or they can disturb the measurement process. There will be presented the sensors as well as a implementation method of the sensor in complex integrated parts which contain the signal processing circuits and the sensing element. We can consider this transducers not a replacement to the present methods (piezoresistive, tensometric, optical, etc), but a viable alternative which is easy to implement.

Sorin Bercea, Constantin Cenusa, Aurelia Celarel, Elena Iliescu
Experimental Approach On The Electrical Capacity Of A Plan-Paralel Ionization Chamber

This paper presents an experimental approach on the electrical capacity of an ionization chamber, of a special shape: the electrodes of the chamber are two plan-parallel plates. The distance between the two electrodes can be varied mechanically; in this way, one can obtain also a variation of the sensitive volume of detector. Such a transducer of a special shape and size is very important in the ionizing radiation metrology, because it allows the use of an absolute method for the measurement of the absorbed dose in beta rays beams or fields.

Page 807 of 936 Results 8061 - 8070 of 9356