Revista elektron

94-99

Authors: Roberto M. Insabella, Martín Germán González

In this work, the source of the artifacts introduced in the images obtained with an optoacoustic tomography system based on the software-defined optoelectronics concept are analyzed and characterized. It is shown that the measured signals are affected both by the cylindrical geometry of the optical sensor and by electrical noise. The latter has well-defined frequencies within the spectrum caused by the electronics used in the heterodyning process of the ultrasound optical detector. A way to include these effects in simulated signals is proposed and the model is tested against measurements. The results of this work will allow the use of the deep learning technique to improve the quality of the images obtained with this type of tomographic systems.

105-111

Authors: Leonardo Martín Carducci, Ramiro Alfonso, Walter Gustavo Fano

This article presents the analog stage analysis of an extremely low frequency (ELF) magnetic field receiver. Details are described about the characterization and modeling of the antenna used, as well as the frequency behavior of the system. To achieve higher sensitivity, a coil was manufactured with a considerably high inductance (800 H), in addition to a high-gain amplification stage (88 dB). An equivalent circuit model was defined for the antenna, and its parasitic elements were determined by laboratory measurements and computational approximations. The acquisition system has a digitization stage with a sampling frequency of 100 Hz. To study its behavior against possible aliasing effects, an analysis of the analog stage in the frequency domain was carried out, determining the optimal operating conditions. Field tests of the equipment were carried out in the mountains of Villa Alpina, Cordoba, Argentina. Taking into account that the system was designed for the measurement and study of natural electromagnetic phenomena in the ELF band, the first six Schumann resonances have been successfully captured and detected.

7-14

Authors: Federico Roffé, Guillermo Oscar Lombardero, Guillermo Sánchez

This project consisted of the design, implementation and calibration of a system for recording variables of the operation of a cooling equipment. It was sought to have parameters for the analysis of efficiency and optimal establishment of the work cycle. The measurement system was implemented in a refrigeration circuit of the Thermodynamics Laboratory of the FACENA-UNNE, considering normal working conditions.

20-31

Authors: Alejandro Fabio Veyrat Durbex, Yaki Nachajon Schwartz, Hernán Tacca

The continuous search for improvement in electromechanical developments requires a clear understanding of the torque measurement required in each application. The decisions made will have a profound impact on the quality and cost of the results. This article presents the principles normally used for sensing mechanical torque on a shaft and the reasons for the widespread use of strain gauges. The importance of differentiation between static and dynamic measurements and the current technologies used in each case are discussed. The relevant factors that define a transducer are described and a comparative analysis between them is carried out, to then examine the possible mounting methods, with their benefits and limitations. Finally, different low-cost solutions are proposed for the design of the torque and speed measurement section without sacrificing system performance, for different test benches for electrical machine controllers, including the necessary signal conditioning electronics. The article aims to be a tutorial compendium of topics to study to successfully implement a test bench without damaging the torque transducer or introducing measurement errors, since the information on these topics is scattered and it is difficult to access knowledge of the selection criteria and project procedures.

37-44

Authors: Carlos Ismael Orozco, María Elena Buemi, Julio Jacobo Berlles

Action recognition in videos is currently a topic of interest in the area of computer vision, due to potential applications such as: multimedia indexing, surveillance in public spaces, among others. Attention mechanisms have become a very important concept within deep learning approach, their operation tries to imitate the visual capacity of people that allows them to focus their attention on relevant parts of a scene to extract important information. In this paper we propose a soft attention mechanism adapted to a base CNN–LSTM architecture. First, a VGG16 convolutional neural network extracts the features from the input video. Then an LSTM classifies the video into a particular class. To carry out the training and testing phases, we used the HMDB-51 and UCF-101 datasets. We evaluate the performance of our system using accuracy as an evaluation metric, obtaining 40,7 % (base approach), 51,2 % (with attention) for HMDB-51 and 75,8 % (base approach), 87,2 % (with attention) for UCF-101.

56-63

Authors: Anibal Fernando Antonelli, Carlos Arturo Gayoso

Within the digital design of programmable logic there is a large number of software, however the need for greater facilities for the users of these systems is observed. The necessary principles of usability can be provided by visual programming languages. On the other hand, to generate synthesizable VHDL or Verilog code in an FPGA through a coherent visual system, it is necessary to overcome multiple drawbacks. This work presents a new visual tool for the design of digital electronic circuits.

70-76

Authors: Matías N. Hadad, Patricio G. Donato, Marcos A. Funes

Narrowband powerline communication systems are widely used in many applications, such as smart metering devices, home automation and low-speed command and control systems. However, power lines were not designed for data transmission and they represent a harsh environment for communication. In the specific bibliography, it is possible to find studies that show the diverse issues of Narrowband Powerline Communication, being the impedance of the grid one of them. The main objective of the present work is to provide a study on the impedance of the grid over this communication band. This study was done in a University environment which has a diverse number of unknown loads, considering the variation with time and location. The data acquisition system developed to conduct the study is shown. The analysis of the results shows that the local grid exhibits issues as least as severe as the ones presented by other authors in different countries and environments.