Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Aquest article exposa què és i en què consisteix la temporalitat queer per a donar compte d‘algunes de les aportacions més rellevants en aquest àmbit emergent d'estudi, així com d’esbossar el diàleg entre les diferents propostes teòriques a propòsit de l’articulació política del queer. Així, a partir d’una lectura conjunta de Lee Edelman, Jack Halberstam, Heather Love, José Esteban Muñoz, Elizabeth Freeman, Sara Ahmed i Lorenzo Bernini s’aborda la qüestió de la temporalitat dels afectes en relació amb el debat de l’assimilació i la transgressió política en la cultura queer. La postulació d’una política queer del temps s’oposa al futurisme reproductiu i a la crononormatividad, translacions temporals de l’heteronormativitat que posen de manifest la vinculació entre les qüestions eròtiques, sexuals i genèriques i les temporals. Destaca la polèmica entre Edelman i Muñoz, els qui discuteixen sobre la viabilitat d'un horitzó futur emancipatori per a la política queer, representant el primer la postura de la negativitat enfront de l’utopisme del segon.

El present article de revisió mostra algunes aportacions del multiculturalisme i els desafiaments entorn de l'educació a Colòmbia a través de recerques desenvolupades en el territori nacional i internacional. Es presenta el desenvolupament metodològic, enfocant-se en la cerca de documents publicats entre 2015-2020 en revistes d'alt impacte i repositoris virtuals per mitjà de la metodologia de revisió sistemàtica de literatura i criteris d'inclusió i exclusió. Finalment, es plantegen recomanacions on es reconeix la necessitat d'articular la multiculturalitat amb els nivells de govern.

This work aims to reconfigure the structure of the emitter of an original offset parabolic reflector to achieve the transmission or reception of circularly polarized (CP) waves. To maintain the same radio technical requirements of the original linearly polarized offset reflector, based on its dimensions, the requirements to be met by the new circularly polarized emitter are analytically defined. For this purpose, the directional characteristics (CD) and the radiation angles it must have to guarantee the G gain requirements and the level of secondary lobes (NLS) required for the antenna are determined. For this purpose, an analytical procedure, developed and theoretically tested in MathCAD, has been developed. In addition, microstrip antennas (AMC) are selected as the most convenient to illuminate the parabola adequately with PC and for their easy fabrication and low cost. In this work, the design of a 2x2 array of AMC ("patches") operating in the frequency band of 1525 - 1559 MHz is proposed; it must also be of small dimensions to minimize the "shadow" effect of the parabola and is fed with microstrip line (MC) to which λ/4 coupling transformers are added. The design is validated with its simulation in the HFSS 13 software, proving that the analytical results are satisfactorily achieved. The proposed procedure has novel reverse engineering elements adjusted to determine the unknown requirements for the parabola and the emitter.

The objective methods of video quality evaluation without references make possible the identification of degradations and noises contained in videos, which are produced by several external factors present in the context of different telecommunication processes: acquisition, compression, processing, or transmission. Identifying degradations in the video is essential to improve its quality. Other processes need to be carried out later, such as detection, recognition of objects, or simply reproducing videos with higher quality. The methods of video quality assessment have evolved from the stage in which it was performed only from the perceptual or subjective evaluation of the quality based on the experience of experts. At the current stage, objective methods predominate using artificial intelligence techniques that perform the analysis from machine learning and are designed using convolutional neural networks. These processes are bio-inspired since they emulate how the human brain identifies noises and distortions in video sequences. This paper summarizes the study of the state of scientific knowledge in the field of video quality assessment methods based on deep learning, which has been developed in the last five years by the international scientific community. We aim to expand the potential for executing the process when large volumes of audiovisual information need to be managed in real-time.

The work describes the proposal for the development of a web application that allows to manage the scientific categories in LACETEL. Various tools and technologies are used, such as PHP programming language, using MySQL as a database manager, Apache as a web server, CodeIgniter as a development framework and NetBeans as a tool. In turn, the Model-View-Controller architectural pattern was used. The solution will allow each of the categorizable workers, and those who already have a scientific category, to prepare their scientific file. Both the file reviewers, as well as the managers at the different instances linked to the categorization process, will be able to observe the stage of the process, the levels of compliance or not by each worker in the preparation of the file, and take decision making in this regard. The solution, in addition, will alert workers about the times of fulfillment, delivery and activities to be carried out to opt for a scientific category.

The present research work proposes the design and simulation of a pentagonal patch antenna with circular polarization for the 2.4 GHz band by means of electromagnetic coupling in a single layer. The proposed configuration aims to be used in RFID (Radio Frequency Identification) systems to achieve good radiation characteristics when sending or receiving data from the RFID tags implanted in the objects to be identified, keeping the design as simple as possible. Circular polarization is obtained through the electromagnetic coupling technique by modifying the dimensions of the antenna feed line and is optimized by introducing disturbances in the geometry of the patch. The proposed antenna has small and acceptable dimensions for possible use in portable RFID readers, a gain of approximately 1.642 dB at 2.44 GHz, impedance matching and circular polarization bandwidths of 111.6 MHz and 138 MHz, which represents a 4.75% and 5.65% respectively of the center frequency of the working band.

The cultivation of sugar cane as a raw material for the production of sugar constitutes the primary link in a large food chain. In the present work, an algorithm proposal was developed for remote sensing of stressed sugarcane crops using digital image processing techniques. The images used were captured in the fields of central Cuba using a multispectral camera, mounted on an Unmanned Aerial Vehicle (UAV). These were then processed on a computer, using algorithms based on the Matlab digital image processing package. The proposed technique used matrix operations between the bands, the Otsu method, and morphological and logical operations. This technique helped to differentiate sugarcane fields affected by stress from healthy crops.

In this article, it is proposed to obtain a calculation method for the estimation of losses in wireless communication systems that use the 802.11b/g/n standards, specifically in security systems in indoor environments. The instrumentation used in the investigation (signal generator and spectrum analyzer) led to subsequent measurements, for which different scenarios were designed to imitate the approximate behavior of the real video surveillance system. Starting from an individual analysis of the measurements in each of the test environments, through the graphic representation of the losses obtained from the measurements taken, a comparison was made with certified empirical propagation models, based on ITU recommendations and the proposed model (obtained with the curve fitting method), allowing to know which of these theoretical models best fits the reality of the designed scenarios. The results obtained from the analysis showed that curve fitting is a possible method for predicting coverage behavior in indoor environments. In the case of this research, based on the mathematical models provided by the Curve Expert Professional software, the resulting model presents an acceptable level of accuracy, compared to the models taken by the UITR P.1238 recommendation in almost all scenarios.

The accelerated technological development and the growing demand for continuous and up-to-date training of university graduates and professionals in Cuban companies, together with the need to promote research activities, have motivated the design and implementation of this training course based on the use of virtual environments. The professional training course Sensors and Sensor Networks was given for companies in the Electronics Group in the form of a distance, synchronous, blended learning course. This article provides information on the procedures for prior coordination, methodological preparation and content development. The evaluation of the course was carried out through tutored mini-projects with asynchronous monitoring. The defence of the work was face-to-face in front of an examining board made up of the course lecturers, allowing individual marks to be awarded. The new practical experiences  ̶ acquired and presented here ̶  in the use of distance or blended learning models are of current interest, as these models are becoming increasingly widespread in the training of human resources in Cuban companies.