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

The aim of this study was to optimize irrigation water in the potato (Solanum tuberosum L. cv INIAP Natividad) crop to ensure the maximum productivity of the crop, using WSN according to the agro-ecological conditions of the area, which have allowed to monitor environmental parameters in potato cultivation and have ensured an efficient control system in irrigation. The WSN irrigation network was implemented using four Arduino modules configured with 6LoWPAN; two modules controlled the solenoid valves together with FC-28 sensors, which capture soil moisture, and through the DHT11 sensor the temperature and relative humidity. The fourth module functioned as a gateway through which information is sent to a database developed in PostgreSQL. Additionally, a Web server (Apache) was configured to visualize the control of the drip irrigation system developed in php, JAVA. It was concluded that the T1 (automated irrigation), which had achieved an evidence with a higher productivity in the potato cultivation in 19.2%, with a water consumption of 20% less than the T2 (manual irrigation). This evidences a clear saving of the hydric resource and an optimum development in the potato crop when comparing it with traditional irrigation system.

En este trabajo se propone el control predictivo económico como técnica para la gestión energética óptima de un vehículo híbrido. Se describe el modelo utilizado para el control y a partir del mismo se diseña un controlador predictivo económico. Finalmente, se estudia el mejor ajuste de los pesos del controlador que consiga la mayor reducción del consumo de la pila de combustible con la ayuda de baterías y supercapacitores. Para ello se determinan los puntos de consumo máximo y mínimo de la pila de combustible, y se caracteriza el problema de control multiobjetivo mediante la determinación de las curvas de Pareto. El artículo concluye con una discusión de los resultados y los trabajos futuros

Ecuador actualmente propone una matriz productiva basada no solo en la extracción de petróleo sino también en la explotación de algunos minerales. Como la minería del cobre, un sector con muchas necesidades por resolver, uno de ellos es el control de peso a la salida del mismo. Por tal motivo, en la Universidad Nacional de Loja se construyó un prototipo a escala de laboratorio de trituración de cobre, se identificó el modelo matemático del mismo, mediante el empleo de dos metodologías para la identificación, una basada en CADCS (Computer Aided diseñado y sistemas de control) y el otro en Ident (sistema de identificación) que posee el software MATLAB®, para optimizar este proceso. A continuación, se presentaron cuatro algoritmos que permitieron controlar en una simulación el proceso de trituración y que son: PID, Smith Predictor y luego los resultados del parámetro más relevante se presentaron en una tabla. Finalmente, el mejor algoritmo de control seleccionado fue implementado con la ayuda de Arduino.

En este trabajo se describe la forma de aplicar la mediana para la demodulación de una señal QPSK y de esa manera recuperar los bits de datos. Los resultados obtenidos muestran que la mediana es una técnica adecuada debido a su simplicidad. Para la modulación de las señales se usaron dos técnicas: síntesis digital directa (DDS) y almacenamiento de fases en memoria. Se compararon estas técnicas para probar posteriormente el funcionamiento del demodulador QPSK. Dicha comparación consistió en probar su eficiencia usando parámetros tales como: consumo de potencia y cantidad de elementos usados; se concluyó que la técnica de memorias es la óptima. Los moduladores y el demodulador con la técnica de tendencia central se diseñaron en lenguaje VHDL y se implementaron en una tarjeta FPGA Virtex-5 de Xilinx.

This prototype was carried out in a lab environment at ESPOCH in Ecuador, using USRP B210 working at 5GHz and two ZJL6G+ amplifiers in cascade connection with 20dB of the total gain to improve the overall system power. Three different samples with different humidity levels were used to determine the risk in diverse conditions in the measurement stage. The sample materials were macadam, soil, and sand. Depending on their humidity level, risks oscillate between maximum and minimum, where high humidity leads to increased risk and inversely. Macadam was the best material for landslides since it showed the lowest permittivity indexes and lowest risk. Results were processed to get reflection and relative permittivity values. Afterwards, they were stored in a database to be analyzed and determine levels of risks simulating landslides as a function of humidity level.

Sudden changes in a greenhouse environment negatively impact the development and production of crops, especially in greenhouses with natural ventilation when temperatures are low at night and change rapidly due to wet winds. To mitigate these variations, a design of a robust controller based on Quantitative Feedback Theory (QFT) as from a Smith predictor structure for the dead-time system is proposed. This structure offers high stability based on the gain margin, the phase margin, and the rejection of disturbances in the system output. This design was contrasted with a PID controller based on performance indices, according to the transient response and error in the presence of changes in the point of operation and charge disturbances. Final results showed that the dynamic response of the QFT controller improved compared to PID controller results.

Versión completa revista MASKAY

Versión completa revista MASKAY

Here, we propose a novel scheme based on advanced techniques of digital modulation in optical communications to achieve a single-channel transmission rate above 100 Gb/s. We utilize a hybrid scheme amplitude/phase/frequency/dual polarization, combined with multidimensional dual lattice and a low-density parity-check-coded modulation. The Stokes parameters are applied to the proposed scheme to map the four-dimensional classical polarization IX, QX, IY, QY in a three-dimensional space. In addition, in the proposed system, the packing theory is applied to the bit interleaver process. Three wavelengths are packaged before being transmitted over a wavelength-division multiplexing optical channel. This modulation process is carried out using symmetrical geometric shapes, such as a hypercube or a polyhedron, based on the molecular links theory using a grouping of 12 and 13/15 bits for the cubic and spherical lattices, respectively. The proposed technique is evaluated in the context of long-distance communications over distances up to 100km. The bit error rate (BER) results showed that the optical signal-to-noise ratio was approximately 4dB over a distance of 50km. In addition, the power spectral efficiency was found to be 3 lambdas, which is considered good performance considering the effects of distance and the non-linear effects influencing the number of lambdas. Also, we use an optical time-division multiplexing scheme (OTDM) in order to achieve a transmission rate beyond 1Tbit/s, where the speed effect is evaluated, taking into consideration that the power spectral efficiency is degraded.

This article describes the design of a wireless network of sensors for monitoring CO2 in the air and noise levels developed for the urban area of the city of Loja. The procedure starts with analyzing the functionality, protocols, and characteristics of the Wireless Sensor Networks (WSN) with the implementation of Zigbee communication technology. Then, the monitoring scenario was determined for the network design through the city's more significant concentration of socio-economic activity. From these scenarios, the sectorization of the city center was preceded, establishing the primary sources of emission of CO2 and noise levels. Then, the simulation was carried out in the Riverbed Modeler software to determine the evaluation parameters, such as the transmission speed, the delay, and the packets received from the chosen technology. Also, the sensor nodes and the coordinating node were designed, which allows the establishment and communication of the network through the XBee PRO S2B module of the Zigbee technology. Finally, to evaluate the designed network, two types of tests were performed: a reception power level test and a validation test of the operation of the network, based on the construction and implementation of prototypes of the proposed sensors, a node coordinator and two sensor nodes (one node for CO2 monitoring and one for noise). The generated information is displayed in a graphical interface developed in the VS Express 2017 software.