Cumbajín Alferez, Myriam
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Preferred name
Cumbajín Alferez, Myriam
Main Affiliation
Ambato
Email
myriamcumbajin@uti.edu.ec
ORCID
Scopus Author ID
57198450868

Research Output
Now showing 1 - 10 of 21
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Improving PV Power Prediction Based on GRU and Meteorological Factors

2026 , Cumbajín Alferez, Myriam , Ruxandra Stoean , José Aguado , Gonzalo Joya

The gradual integration of renewable solar energy sources represents a major step toward sustainability, which is why the main objective of this study is to design an optimized GRU architecture for hourly prediction of photovoltaic generation, considering both single-step and multi-step forecasting. A recurrent neural network with a four-layer GRU structure was implemented, selected after a comparative validation process in which different depths were evaluated. This configuration balanced accuracy, stability, and generalization capacity, improving the model’s ability to capture complex relationships between the endogenous variable (photovoltaic generation) and a set of eight exogenous meteorological variables. This architecture proved robust to different sets of predictors, maintaining consistent performance under different input configurations. The result is a reliable prediction and forecast error for a power generation system with meteorological factors typical of Ibarra, Ecuador. Among the evaluation metrics used, the mean square error decreased by 19.61% and 23.69% for single-step prediction and multi-step forecasting, respectively. Therefore, the GRU model has managed to reduce the error by a moderate percentage, with a significant difference, supported by the evaluation metrics and the Wilcoxon-Mann-Whitney U test, it was possible to reduce the error obtaining a p-value less than 0.05, which represents that the data groups without meteorological factors and the data groups with meteorological factors are statistically different and therefore the error reduction is significant. Through this, it is demonstrated that including eight exogenous attributes reduces prediction and forecasting errors

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Smart Antenna Array for Optimal Electromagnetic Energy Capture

2023 , Cumbajín Alferez, Myriam , Sánchez, Patricio , Escobar E. , Gordón C.

Smart antennas are currently one of the most exploited fields in terms of wireless networks, allowing high data transmission capacities, this is achieved by focusing the radiation on the desired direction and adjusting to the environment and conditions in which communications are developed. Smart antennas employ a set of radiating and emitting and combining elements organized in the form of arrangements connected at a common point to guarantee the required power, the signals from these elements are combined to form a moving beam pattern that follows a pattern determined by the user or designer. The consumption of energy within communication systems is considered a big problem and a challenge when carrying out implementations in media where the storage or recharging of the end terminals is complicated by their location, this trend grows with the presence of the Internet of the IoT things, where it is directly dependent on the construction of a large wireless network that allows everything to be interconnected, for this reason there are investigations in the 2.4 and 5.8 GHz bands and represents future work for the 5th Generation (5G) cell phone. The great possibility of collecting electromagnetic energy from densely populated urban areas becomes a great renewable source of power for communication devices for both existing Wi-Fi technology and new technologies such as the 5G network. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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RF Energy Harvesting System Based on Spiral Logarithmic Dipole Rectenna Array

2023 , Cumbajín Alferez, Myriam , Sánchez, Patricio , Pillajo D. , Gordón C.

This paper presents the development, design, simulation and fabrication of a logarithmic spiral antenna array for the electromagnetic energy collection system independent of frequency, compact in microstrip technology, low cost and operating within a range of frequencies. 1 to 4 GHz, are designed using the CST Studio software that allows modeling and simulating essential parameters such as radiation lobes, VSWR, power, gain, parameter S11. From these simulations the printing is done on an RF4 substrate with a thickness of 1.6 mm, a dielectric constant of 4.4 and an input impedance of 50 Ω. The resonator structure antenna with dimensions of 190 × 210 mm. The frequencies obtained with the rectenna matrix, since it offers good performance for electromagnetic energy harvesting applications that operate in standard frequencies such as GSM, WiFi, LTE which are available in the environment and allows us to collect energy. To obtain electrical energy as part of the design of a frequency rectifier which is optimized with the application of the Schottky diode. In addition, its construction of the rectenna matrix was carried out based on the proposed design, then performance tests and validation of the prototype were carried out using the miniVNA Tiny spectrum verifier, and finally energy storage tests were carried out. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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Michell-Banki a Promise Turbine for Pico-Hydro in Water Irrigation Channel

2020 , Ibañez, L. , Escobar, L. , Hidalgo, A. , Gordón, C. , Cumbajín Alferez, Myriam

We report the design, manufacture, and testing of the Michell-Banki turbine by using the hydraulic data of the Ambato - Huachi - Pelileo water irrigation channel in the Tungurahua province in Ecuador. The turbine has the blade, impeller, flange and shaft that are purely plastic materials because they will be subject to the action of water and thus be able to extend the life of the components. For an optimal design it was considered an efficient alternative, which is the manipulation of the turbine, it should be portable and as light as possible. When performing the tests, it was determined that there is an error around 14% between speed and torque calculations, while the greater efficiency of the turbine is at the exit of each oval of the channel. The main contribution of the present work is to provide the required promise component in a Pico-Hydro that is expected to be implemented in the water irrigation channel. Also this work aims to provide several benefits to the society bordering the irrigation channel, such as generating energy for self-consumption as a contribution to the lighting of the channel at no cost to the people. © 2020, Springer Nature Switzerland AG.

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Multiband Microstrip Antennas for Energy Harvesting Systems

2022 , Gordón C. , Criollo W. , Cumbajín Alferez, Myriam , Peñafiel C.

In this paper, the development of two microstrip antennas for electromagnetic energy harvesting systems is presented. The first one, is the Hybrid Resonator Planar Structure Antenna operating at a specific 900 MHz frequency, while the other is an Archimedean Spiral Multiband Antenna working in a frequency range of 1 to 3 GHz, both were developed for energy harvesting systems. Both antennas were designed using CST Studio software and fabricated in a low cost FR4 substrate with a thickness of 1.6 mm, dielectric constant of 4.4 and an input impedance of 50 Ω. The frequencies achieved with the antennas are very promising, as it offers good performance for electromagnetic energy harvesting applications since it operates at standard frequencies such as GSM, Wi-Fi, LTE and UMTS which are available in the environment and allow us to harvest energy at any place and any time. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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Reverse Engineering for the Ecowitt WS90 Weather Station

2026 , Cumbajín Alferez, Myriam

This article presents a comprehensive reverse engineering study applied to the Ecowitt WS90 weather station, a self-contained device designed to collect essential environmental data such as temperature, humidity, wind direction and speed, light and UV radiation levels, and precipitation. The main objective of this work is to gain a deep understanding of the internal workings of the weather station through meticulous analysis of its hardware and software components. The methods used are described in detail, including careful disassembly of the device, precise identification of key components, and scanning and disassembling the embedded firmware. Additionally, significant challenges encountered during the rigorous reverse engineering process are discussed and possible improvements or modifications to the original design based on the findings are proposed. The results obtained in this study provide an unprecedented insight into the internal workings of the Ecowitt WS90 weather station, contributing to a deeper understanding of environmental monitoring systems in general. The detailed findings presented in this article can be very useful for future developments and advances in the field of environmental monitoring, by facilitating the optimization of existing devices or the design of new innovative solutions. Furthermore, this work lays the foundation for future research and more specialized studies in the area of reverse engineering applied to environmental data acquisition systems. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2026.

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Integration of renewable energies in conventional power systems based on computational reliability

2019 , Cumbajín Alferez, Myriam , Ramírez L. , Gordón C.

We report the successful computational reliability of integrating renewable energy into conventional electric power systems. According to renewable resources available in the province of Imbabura in Ecuador, where there are sufficient renewable resources to generate clean energy with three types of technology, such as wind energy, photovoltaic solar energy and thermoelectric energy. We have been able to conduct two fundamental case studies, and then calculate reliability indices using the non-sequential Monte Carlo method using Matlab programming. The reliability indices allowed us to evaluate the reliability of the system. Due to the fact that the lower the reliability index, the higher the reliability of the system. As a result, this paper provides a promising method for increasing the reliability of electric power systems and supporting the future integration of renewable energies. © 2019, Associacao Iberica de Sistemas e Tecnologias de Informacao. All rights reserved.

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Convolutional neural network oriented to the gesticulation control of an interactive social robot with humanoid aspect [Red neuronal convolucional orientado a la gesticulación de un robot social interactivo con aspecto humanoide]

2019 , Arias E. , Encalada P. , García M. , Granizo C. , Tigre F. , Cumbajín Alferez, Myriam

Social robots present the boom of an infinity of investigations in terms of design and control, these in turn approach with greater intensity to be our partners at home or work, however, still lack similar social interaction skills to the human being. This paper presents the implementation of a convolutional neuronal network algorithm aimed at the arrest of emotions for decision-making in the gesticulation of the social robot with a humanoid appearance. In addition, emphasis is placed on the use of visemas as a unit of labial movement for improve the human-robot interaction in any field in which the social robot can be used, be it teaching, therapies, safe navigation, etc., simultaneously coordinating and similar to the human naturalness the movement of servomechanisms of the mouth and the synthesized audio of the text that the robot gives in response. © 2019, Associacao Iberica de Sistemas e Tecnologias de Informacao. All rights reserved.

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Suitable electric generator for pico-hydro power plant in ambato–huachi–pelileo water irrigation channel

2020 , Cumbajín Alferez, Myriam , Sánchez, Patricio , Hidalgo, A. , Gordón, C.

We present the analysis of the selection of electric generator suitable for Pico-Hydro Power Plant in the Ambato-Huachi-Pelileo irrigation channel in Ecuador. For which a meticulous literary review has been carried out about the main characteristics of the Pico-Hydro Power Plant as it is the height, the hydric resource, the turbine and the generator. Considering the water resource, which in our case is provided by the Ambato-Huachi-Pelileo irrigation channel, the parameters of low height and slow speed have been taken around 1.6 m3/s, which has allowed us to analyze the generator suitable for the required Pico-Hydro Power Plant. Therefore, the study conducted has allowed us to conclude that the electric generator suitable for the Pico-Hydro Power Plant in the Ambato-Huachi-Pelileo irrigation channel is a radial flux permanent magnet generator that is capable of providing sufficient electrical power with a simple structure, low revolutions, and high efficiency. Also, a Matlab simulation was developed in order to predict the power which is capable of provide the radial flux permanent magnet generator which in this case is 3.8 KW. This work aims to provide several benefits to the society bordering the irrigation channel, such as generating energy for self-consumption as a contribution to the lighting of the channel at no cost to the public in order that it is not dangerous for the passers at night and providing the ability for maintenance works at any time. © Springer Nature Switzerland AG 2020.

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Health and Educational Impacts Reduction Using a Supervisory Control and Data Acquisition Web System

2018 , Davila L. , Robalino F. , Gordon C. , Cumbajín Alferez, Myriam

We present the design and implementation of a Supervisory Control and Data Acquisition SCADA web system of pollution factors such as Nitrogen Dioxide (NO2), Carbon Dioxide (CO2) and Carbon Monoxide (CO) in order to manage them, providing comfort in indoor environments. The SCADA web system allows a comparative analysis of the recorded information with the alert, alarm and emergency levels, established in the Ecuadorian air quality regulations, annex 4 of Book VI of the Unified Legislation of Secondary Legislation of the Ministry of the Environment., The SCADA web system performs the comparison of the registered information, with the physical agents of environmental comfort, established in the ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) standards. In the process of stabilization of the pollution factors, in indoor environments, air ionizers are used, which emit negative ions to maintain the standardized range in micrograms per cubic meter (3). Finally, we have been able to develop a SCADA web system for controlling pollution factors in indoor environments thanks to the integration of firebase (Android Studio), authentication (Facebook), notification (Database and Web Server), control and monitoring (Android Studio) interfaces. Besides, the SCADA web system allows preventing long term health problems such as allergic reactions, physical exhaustion and respiratory diseases, which influence academic performance during study days in educational institutions. © 2018 IEEE.

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