Maskay is a scientific journal with semestral periodicity edited by the Department of Electrical, Electronics, and Telecommunications Engineering of the Universidad de las Fuerzas Armadas ESPE since 2011. Each volume of the Maskay journal comprises two issues; the first corresponds to the period between December and May, whereas the second number covers the period between June and November of each year. Makay journal is indexed in SciELO-Ecuador, Latindex, LatAmPlus, RootIndexing, MIAR, DOAJ, Directory of Research Journals Indexing, Dialnet, and REDIB (Red Iberoamericana de Innovación y Conocimiento Científico) platform; seeking to be a benchmark of advances related to Electrical and Electronic Engineering in the region.
Authors who publish in this journal agree to the following terms: Authors retain the copyright and guarantee the journal the right to be the first publication of the work, as well as, licensed under a Creative Commons Attribution License that allows others share the work with an acknowledgment of the authorship of the work and the initial publication in this journal. Authors may separately establish additional agreements for the non-exclusive distribution of the version of the work published in the journal (for example, placing it in an institutional repository or publishing it in a book), with acknowledgment of its initial publication in this journal. Authors are allowed and encouraged to disseminate their work electronically (for example, in institutional repositories or on their own website) before and during the submission process, as it may lead to productive exchanges as well as further citation earliest and oldest of published works.
Maskay Vol. 16 No. 1
Copyright (c) 2025 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/
Maskay Vol. 15 No. 2
Application of artificial intelligence in the Internet of Things: a documentary study
The convergence of the Internet of Things (IoT) and Artificial Intelligence (AI) has catalyzed substantial advancements across multiple sectors, including agriculture, security, healthcare, home automation, and resource management. This paper presents a systematic literature review aimed at identifying key applications, AI techniques, and benefits resulting from the integration of these technologies. The review process was conducted in accordance with the PRISMA methodology, encompassing publication selection, data extraction, and analysis. Out of 725 initially retrieved records, 53 studies were selected for detailed examination. The results indicate that multisensor systems represent 28.85% of the reported applications, followed by IoT security (21.15%) and smart cities (15.38%). In terms of AI techniques, multisensor data fusion was the most frequently employed (40.38%), followed by deep neural networks (19.23%) and support vector machines (15.38%). Most of the reviewed studies report accuracy levels of 90% or higher. These findings highlight the critical role of AI in enhancing IoT systems and identify the domains with the highest potential for future development.
Design and simulation of circularly polarized, quasi-square microstrip antennas for microsatellites: A practical guide to simulation with HFSS™ software
This paper presents a practical guide for the design of a Right-Hand Circular Polarization (RHCP) microstrip antenna using HFSS software. The design considers an antenna to acquire information transmitted by the Global Positioning System (GPS) in the L1 band. This signal is used by the Attitude Control Unit (ACU) to improve the positioning control of a microsatellite traveling in a Low Earth Orbit (LEO). Following the proposed procedure, values of an Axial Ratio (AR) of 1.22 dB, a directivity of 5.14 dB in the broadside direction, and an AR bandwidth of 15 MHz were obtained.
Design of a predictive control tuned by an evolutionary algorithm applied to a nonlinear conical tank level
The control of nonlinear dynamic systems, such as the liquid level in a conical tank, poses a critical challenge in various military applications, particularly for handling heavy liquids and slurries. This paper presents the design of a Model Predictive Control (MPC) algorithm that uses Particle Swarm Optimization (PSO) and Least Squares (LS) to control the liquid level in a conical tank. A prototype was built in a laboratory at the Universidad de las Fuerzas Armadas ESPE. The research highlights the limitations of traditional control methods, which fail to achieve a fast transient response and often cause overshoots. In the face of this problem, the incorporation of tuned evolutionary algorithms for MPC control is proposed to improve control performance for nonlinear systems.
Comparison of interior propagation models of the Wi-Fi network at the 5785 MHz band through RSSI measurements
This study presents a comparative analysis of the Cost231-Multi-Wall Model, the Motley-Keenan Model, the Modified Free Space Model, and the Log-Normal Shadowing Path Loss Model, applied to a 5G Wi-Fi network in an indoor analysis. The research seeks to recommend the most appropriate small-scale propagation model based on empirical measurements of signal strength. Initially, the router is located within the analysis area. Then, a detailed sketch is made in SketchUp, locating 133 points around the primary router, covering the entire indoor area of the analysis, ensuring an accurate assessment of the cellular network coverage. Subsequently, with the data collected over three campaigns, propagation losses were calculated to determine the theoretical power of each model and compare the measured power values with the theoretical power values to obtain a specific model. The four propagation models analyzed in the evaluator are based on data obtained in the range [-20 to-91] dBm. It was concluded that the Keenan-Motley propagation model offered a better fit to the measurements, presenting a value of 12.59 dB. In contrast, the Cost 231 model showed a value of 17.18 dB, the Modified Free Space model showed a value of 26.47 dB, and the Log-Normal Shadowing Path Loss model showed a value of 27.57 dB, indicating a greater discrepancy concerning the measured data. This model demonstrated greater accuracy in predicting the reception power compared to the other analysis models, adapting better to the specific characteristics of the environment. These results highlight the importance of strategically locating the router; therefore, it is recommended to locate it in a central location.
Systematic analysis of data security protocols in cloud computing: Literature review
This paper presents a systematic review of relevant studies published between 2019 and 2024, focusing on data security protocols in cloud computing environments. The selection process was based on rigorous criteria to identify the most relevant features of these protocols and their current applications. The review examines their advantages as well as the cryptographic mechanisms used to protect sensitive data, including Advanced Encryption Standard (AES), Rivest–Shamir–Adleman (RSA), and Elliptic Curve Cryptography (ECC). Additionally, the increasing use of Kubernetes as a container orchestration tool is analyzed, acknowledging its significance in modern cloud infrastructures. Within this context, several studies are reviewed that highlight implementation limitations such as inadequate privilege management and the reliance on third-party solutions. This research aims to provide a comprehensive understanding of current trends and challenges in cloud data security and to support the identification of potential strategies to address these issues and enhance the robustness of cloud-based security architectures.
Uplink performance evaluation of wireless networks based on IEEE 802.11g and IEEE 802.11n under co-channel interference
Due to their widespread use, wireless networks conforming to IEEE 802.11g/n standards can experience channel saturation, leading to interference that affects their performance. This study analyzes the performance of these networks under various interference scenarios, evaluating their behavior in terms of Quality of Service (QoS) metrics, including throughput, delay, jitter, and packet loss. Experiments were conducted in indoor environments using two standards, IEEE 802.11g/n, and different channel configurations. Initially, networks were evaluated in scenarios where all devices operated on the same channel (1, 6, or 11), creating co-channel interference. Subsequently, scenarios were analyzed where each access point operated on a different channel to minimize interference. The intrusive traffic injection technique was employed for data collection, enabling precise measurements of the analyzed metrics. The results indicate that network performance varies significantly depending on the standard used and the channel configuration. Overall, networks operating under the IEEE 802.11n standard exhibited better throughput performance but were more susceptible to interference compared to those operating under the IEEE 802.11g standard. Additionally, transmission efficiency decreased significantly in the presence of co-channel interference, with performance losses of up to 35% in some scenarios. These findings underscore the significance of effective channel planning in wireless networks, enabling optimal performance and mitigating the adverse effects of interference.
Performance evaluation of IEEE 802.11g/n compliant wireless networks under different interference scenarios: Downlink
In this study, the performance of IEEE 802.11g and IEEE 802.11n wireless networks was investigated under different interference scenarios. Quality of service metrics include throughput, delay, delay variability, and packet loss rate. Experiments conducted in intra-apartment environments began with co-channel interference, with all devices connected on the same channel. Each device then broadcasts on a different channel, thereby minimizing interference. Intrusive traffic in the protocol was used for precise metrics measurements. Results indicate that performance varies depending on the standard and channel configuration. Overall, IEEE 802.11n offers superior performance, although it is more susceptible to interference compared to IEEE 802.11g. Transmission efficiency suffers significantly in the presence of co-channel interference, with throughput losses reaching up to 35% in specific scenarios. This study underscores the importance of proper channel planning to maximize throughput and mitigate the adverse effects of interference.
Copyright (c) 2024 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/
Copyright (c) 2023 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/
Copyright (c) 2022 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/
Copyright (c) 2021 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/
Prototype of a self-sustainable weather station for real-time monitoring of climate variables in Salinas
This research proposes the development of a low-cost weather station prototype integrating microcontrollers, environmental sensors, and IoT technology, aiming to evaluate its measurement accuracy through comparison with official data from Ecuador’s National Institute of Meteorology and Hydrology (INAMHI). The study examines key meteorological variables, including temperature, humidity, UV-A radiation, air quality, atmospheric pressure, and wind speed/direction, employing an experimental quantitative methodology structured in sequential phases: technological architecture design, system implementation, and data validation. For data validation, rigorous statistical methods were applied, including: individual error determination, standard deviation analysis, margin of error calculation, and Mean Absolute Percentage Error (MAPE)1. Results demonstrate acceptable error margins across critical variables: temperature measurements showed a mean error of ±0.3°C (MAPE: 1.15%), humidity displayed a -2.8% bias (MAPE: 6.7%), while atmospheric pressure achieved exceptional precision (MAPE: 0.034%). This work validates the prototype’s technical feasibility. It establishes a methodological framework for optimizing meteorological sensors in coastal environments like Santa Elena, Ecuador, ultimately contributing to more accessible and reliable environmental monitoring systems.
Biometric System: Study of Radiation on the Human Arm
The study assessed radiation power absorption in the 1.5 to 5 GHz range for Wi-Fi, LTE, and AM modulation, using three Vivaldi antennas in an anechoic chamber with a phantom arm made of animal bone, ballistic gel, and pigskin. Wi-Fi showed the highest absorption levels, but these values (0.168 mW and 0.050 mW) were below ICNIRP safety limits, indicating no significant risk to human health.
Design and implementation of a patch-fractal antenna with phase control using Butler matrix
The study presents the successful design and implementation of a phase-controlled patch-fractal antenna using the Butler array. This work focuses on developing a laboratory prototype of a 4x4 array using microstrip technology. Theoretical conditions are established, and the theoretical basis of the microwave circuits that make up the matrix is described. Each element is individually designed, optimized, and simulated using specialized software (Ansoft Designer and Advanced Design System), and then its performance is verified by evaluating functional parameters. The tested designs are integrated into a single circuit to form the Butler matrix and are subjected to simulation and optimization before manufacturing. The functionality of the components is verified using a vector network analyzer. An analysis of the discrepancy between the measured values and the theoretical target parameters is performed, providing a comprehensive evaluation of the prototype's performance. Implementing the 4x4 Butler matrix together with the design of patch-fractal microstrip antennas has allowed practical phase control, demonstrating its viability in various applications. Results from both simulation and laboratory tests support the ability to direct the radiation lobe in various areas without the need for additional mechanical structures. The applicability of this antenna in short-range radar systems is highlighted, offering flexibility in addressing without compromising essential electromagnetic properties. For future applications requiring more precise control with a more significant number of radiation lobes, a Butler array with more ports is suggested.
Construction of a micro-hydroelectric generator based on a lower intake crossflow turbine
The study focuses on developing a micro-hydroelectric generator using a bottom inlet cross-flow turbine that takes advantage of the hydraulic potential of irrigation canals. The methodology used is quantitative and experimental and is based on a flow chart describing the stages from the creation to the implementation of the prototype. Variables such as water height and flow, as well as the dimensions of the irrigation canal, which could not be modified due to the agricultural activities carried out at the site, were taken into account. The results obtained from the field implementation of the designed prototype show that the generator can reach a power value of 93 W with an efficiency percentage of 11.3%, which sustainably produces energy in remote areas. In conclusion, the study highlights the need to explore new renewable and sustainable energy sources in response to the current energy crisis affecting society; it emphasizes the need to adopt cleaner energy alternatives that limit dependence on non-renewable resources while controlling the adverse effects of climate change.
Use of the 433MHz band for underwater communications in controlled environments
This research aims to design and implement an underwater communication system using radio frequency modules and Arduino. Underwater wireless communication is challenging due to the attenuation of electromagnetic waves in water. However, radio frequency signals in the 433MHz range and the added antenna have successfully transferred data. For this purpose, measurements are made at different distances, and data is collected in the aquatic environment and free space. A comparative analysis of the values of arrival powers and losses in the studied environment is carried out to verify the efficiency of this study in terms of range, transmission speed, and reliability.
Design of an optical-wireless system for the analysis of free space optics technology
In this paper, a study oriented to Free Space Optics (FSO) is carried out, identifying its main benefits and limitations. A practical case study is also considered in the city of Loja (Ecuador) for designing FSO technology, assessing suitable sites for deployment, climatic conditions and line of sight between the selected nodes, and technical characteristics of the equipment considered. Path loss and channel geometry analyses are also performed, where the results obtained allow understanding under which atmospheric conditions an optimal link is available. The study is validated by executing simulations using Optisystem software and considering several study scenarios. One of the actual results identified is the transmission rate supported by FSO technology in different atmospheric conditions, exceeding 3 km, and the high bandwidth offered compared to other technologies, such as RF, that are limited by similar factors.
Comparative analysis of propagation models in mobile telephony in the 1900 MHz band (LTE) using electric field measurements in Ambato city
This paper presents a comparative analysis of the propagation models Hata Extended, SUI with a frequency correction factor, and Ericsson 9999 in mobile telephony systems operating in the 1900 MHz band (LTE). The study is carried out by measuring the electric field to establish a recommendation for an existing propagation model that fits the characteristics of the urban area of Ambato City. First, five base stations were located. Then, two base stations working in the band and technology mentioned above are chosen. Subsequently, four radial limits were drawn in the surroundings of the base stations, and four electric field measurement campaigns were carried out with the Narda SRM-3006 equipment for a total of 48 points for 6 minutes per point. In addition, the coordinates of the measurement points were determined using the Spectra Precision Mobile Mapper 50 equipment, obtaining the distances and heights of the terrain with great precision. With the data collected, the propagation losses are calculated to bring the theoretical electric field of each propagation model. Next, a comparison of the measured electric field values concerning each model's theoretical electric field values is performed to evaluate which model best fits the measurements. Also, a comparison of the RMSE is made. Finally, it is concluded that the SUI model with frequency correction factor is the best fit for the urban environment in Ambato.
Comparative analysis of propagation path loss models for mobile communication in Riobamba
Propagation loss models play an essential role in the planning and designing of a cellular network to determine critical aspects of the system, such as optimization, power level adjustments, and placement of wireless network antennas. In addition, these models are used to predict path loss in a given environment. This paper analyzes and compares different propagation models based on measured data: The log-normal Model, the Okumura-Hata Model, the Standford University Interim (SUI) Model, the COST-231 Model, and the Walfisch-Bertoni Model. The power measurement data is taken in 5 urban sectors of Riobamba at an operating frequency of the Claro telephone network of 1900 MHz with the help of the Network Cell Info Lite application. The analysis and comparison results conclude that the Log-Normal and SUI models perform best in the five environments.
Dual-band monopole antennas for RF energy harvesting from the environment
This paper presents two low-cost dual-band antennas for collecting ambient RF energy from the GSM-850, GSM-1900, and UMTS-2100 MHz bands. Both rectennas (Rectifying Antennas) are based on Defected Grounded Structure (DGS) antennas. The first one is designed with a square resonator ring. The bandwidth is between 73.4 and 145 MHz, with a gain of 2.29 and 3.53 dBi. The other has a bandwidth of 86 and 124.8 MHz with a gain of 1 and 3.8 dBi. In addition, a triple-band rectifier with an HSMS-286C Schottky diode is used to improve the RF to DC power conversion efficiency. Measurement results show that between 150 and 308 mV of DC is harvested during 8 hours at 50 meters from a telephone base station. In 86 continuous hours of exposure to this station, a DC voltage between 4.0 and 4.50 volts of ambient RF energy is obtained.
This article reviews the Citizen Broadband Radio Service (CBRS) and its characteristics. It also describes the Spectrum Access System, which allows the bands not used by primary users to be intelligently occupied by secondary users to optimize this resource. As a rule, CBRS operates between 3550 and 3700 MHz, allowing users to connect with operators in high-traffic locations. Using Neutral Hosts minimizes the installation and operation costs of the Advanced Mobile Service’s operators. CBRS also functions as a private LTE network with several advantages over other wireless network technologies. This innovative proposal marks a milestone in shifting from fixed radio spectrum allocation to dynamic controlled access, enabling connectivity to a wide range of wireless devices.
Risk level measurement system for landslide zones using SDRadar technology in a lab environment
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 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. Risks oscillate between maximum and minimum depending on their humidity level, 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. Afterward, they were stored in a database to be analyzed, and simulated landslides determined levels of risk as a function of humidity level.
Copyright (c) 2019 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/
Robust multidimensional optical modulation based on hybrid subcarrier/amplitude/phase/dual polarization for wavelength-division multiplexing systems
Here, we propose a novel scheme based on advanced digital modulation techniques 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, and QY in a three-dimensional space. In addition, the packing theory is applied to the bit interleaving process in the proposed system. Three wavelengths are packaged before being transmitted over a wavelength-division multiplexing optical channel. This modulation process uses 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 50km. In addition, the power spectral efficiency was found to be three lambdas, which is considered a 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) to achieve a transmission rate beyond 1Tbit/s, where the speed effect is evaluated, considering that the power spectral efficiency is degraded.
Handmade LED phototherapy for the treatment of jaundice compared with other technologies
Phototherapy is the treatment indicated for the management of neonatal jaundice. There are different technologies to provide this treatment, including LED devices. For this study, an LED phototherapy lamp is developed for neonatal jaundice. Its efficacy is compared with other devices by measuring the speed at which it reduces bilirubin levels. This lamp is built with an LED light source composed of a 15×25 LED array that generates 460nm. This device is characterized by a very compact source of low energy consumption, long duration, and low cost. The results are comparable with industrial manufacturing devices but are less expensive and, therefore, more efficient regarding health costs.
Design of a WSN for monitoring CO2 in the air and noise levels in Loja
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 by analyzing the functionality, protocols, and characteristics of the Wireless Sensor Networks (WSN) and 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 CO2 emission and noise levels. Then, the simulation was carried out using 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 to allow 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.