Marcus Vinicius Viegas Pinto, Noara Foiatto, Joao Miguel Lac Roehe, Marcos Augusto Stemmer
Uncertainty to harmonic measurements with DFT techniques

The harmonic content generated by the use of non-linear loads can cause an electrical device to operate improperly. For this reason, reliable measurements of this parameter are fundamental to guarantee the results needed by the electronics industry and medical devices. The aim of this work is to describe the development of a measurement system of harmonic signals with traceability to the international system of units (DC voltage), and its uncertainty levels. The system consist a software developed in Visual Basic language based on a voltmeter with a General Purpose Interface Bus (GPIB) able to digitalize a signal with sampling rates up to 100,000 samples per second. A Discrete Fourier Transform algorithm is used to evaluate the harmonic content of the signal. The work consists of a tool for the calibration services provided by the laboratory LABELO-PUCRS, and its results indicate the best capability (uncertainty) to harmonic measurements.

Marius Branzila, Valeriu David
Wireless Intelligent Systems for Biosignals Monitoring Using Low Cost Devices

In this paper we propose a system able to monitor biosignals, to record information on SD card or to send relevant data remotely. This application demonstrates how to develop new wireless intelligent system, to be future used in processing, analyzing and extracting necessary features from biosignals, easily and conveniently. Artificial intelligence improves the biosignals monitoring efficiency and help critical caretakers to speed up a prior diagnose. With LabVIEW and related toolkits, such as the Advanced Signal Processing Toolkit (ASPT) and the Digital Filter Design Toolkit (DFDT), we can conveniently build signal processing applications for both stages(preprocessing and filtering), including baseline wandering removing, noise cancellation, QRS complexes detection, fetal heart rate extraction and etc. We also discuss typical ECG signal processing methods based on LabVIEW and we present the developed improvements for preprocessing and processing ECG signals for QRS complexes, using different function from LabVIEW.

Néstor Castro Ingaroca, Juan Moises Mauricio Villanueva, Raimundo Carlos Freire, Thiago de Carvalho Batista
Crack Size Identification and Locatization Using Ultrasonic Sensors with Stationary Wavelet Transform and Hilbert Transform

This paper presents a method for locating and measuring the size of cracks in beams by time of flight (ToF) of ultrasonic wave. The echo detected was processed using the stationary wavelet transform and the Hilbert transform. The accuracy of the information obtained from the processed signal depends on the selected mother wavelet. To select the best mother wavelet for signal processing were used the Shannon’s entropy criterion. The ToFs were obtained from denoising process using the stationary wavelet transform and the envelope of the Hilbert transform. The uncertainties of the ToFs using Fuzzy numbers are also estimated in order to assessment the qualities of the ToF Measurement.

Alessio Carullo, Franco Ferraris, Alberto Vallan, Filippo Spertino, Filippo Attivissimo
Long-Term Monitoring of Photovoltaic Plants

This paper deals with a data-acquisition system that has been specifically developed for a long-term monitoring of ten different photovoltaic plants. The main goals of the system consist in estimating the drift of the plant components, mainly photovoltaic modules and power inverters, and comparing the performance of the ten plants, which are based on different technologies and architectures. Owing to these goals, the traceabilityassurance of the obtained measurements is mandatory, hence the data-acquisition system has been designed to be easily calibrated and, if necessary, adjusted to compensate for measuring-chain drifts. In addition, the measurement uncertainty, which has to be suitable to distinguish the behaviour of the different PV plants, has to be stated for each of the estimated parameters. A brief description of the data-acquisition system is provided and its measurement capabilities are highlighted in terms of measured quantities and expected uncertainty. Results that refer to a period of thirty months are also reported.

Cristian Zet, Cristian Fosalau, Daniel Petrisor, Catalin Damian
Landslide transducer based on amorphous wire strain gauges

The paper presents a landslide transducer based on amorphous wire strain gauges. Four such strain gauges are mounted on a flexible tube and connected in a Wheatstone bridge powered with a 1 MHz sine wave. The voltages from the mid points of the two arms of the bridge are amplified and further peak detected. The transducer is build around a low power microcontroller. The voltages from the peak detector are converted into digital data and the displacement and the direction are computed and corrected. The result is sent via a serial interface toward a central unit.
The originality of the paper consists of the use of such strain gauges as sensitive elements and processing of the signals for landslide detection. The results show higher sensitivity than classic strain gauges and the possibility to detect the direction of the displacement.