Oscar Osvaldo Ordaz-García

Science, technology, engineering, and mathematics (STEM) education in Mexico currently offers an opportunity to adopt immersive virtual reality (VR) as a supplement to teaching methods in elementary education. This article presents the user-centered design (UCD) and exploratory classroom evaluation of Vulcanus, an immersive VR application for volcano-related STEM activities aimed at elementary school students aged 11 to 12. The application combines guided audiovisual content, hand tracking, rover assembly, and robotic exploration tasks. Forty-eight students participated (24 per condition); the 24 VR users completed questionnaires on experience, discomfort, and usability. The results showed an adapted experience score of 32.12/40; the adapted 10-item distress scale yielded a descriptive mean of 5.37/30, and an adapted System Usability Scale (SUS) score of 69.23/100. The classroom intervention included historical knowledge questionnaires; however, their scores were excluded from the main findings because the original open-ended response scoring could not be independently audited. The contribution of this article is the design and exploratory evaluation of an educational VR application with hand tracking.

La evidencia muestra que los modelos de machine learning (ML) se han utilizado para analizar patrones complejos en la cobertura de vacunación contra COVID-19, los efectos adversos y la respuesta inmune medida por anticuerpos. El objetivo de esta revisión es sintetizar sistemáticamente la evidencia sobre la aplicación de ML en estos tres dominios. Se incluyeron estudios originales publicados entre 2020 y 2025 mediante una búsqueda en MEDLINE/PubMed, Scopus, Web of Science, IEEE Xplore y ACM Digital Library. Se extrajeron variables relacionadas con población, predictores, algoritmos, métricas de desempeño e interpretabilidad, y el riesgo de sesgo se evaluó mediante PROBAST. En total, se incluyeron 62 estudios, destacando el uso frecuente de gradient boosting, random forest, redes neuronales y modelos multivariados. Los predictores más relevantes incluyeron factores sociodemográficos, psicológicos y clínicos, como comorbilidades y marcadores inmunológicos. El desempeño predictivo se reportó de moderado a alto, con especial efectividad de gradient boosting en la hesitación vacunal, y modelos multivariados en predicción de anticuerpos. Las principales limitaciones incluyeron muestreo no probabilístico, uso de datos autoinformados y falta de validación externa. En conjunto, los resultados evidencian el potencial del ML en salud pública, aunque resaltan la necesidad de mejorar la estandarización, transparencia y calidad metodológica.

Small-scale clay-brick yards require molding equipment that increases output while remaining mobile, locally serviceable, and compatible with intermittent material supply. This article documents the functional architecture and exploratory operational performance of the mobile 12-cavity hydraulic clay-brick molding machine (ML12). Its design contribution is the integration of a dimensioned wheeled steel chassis, seated paired-lever controls, a translating feed hopper/distributor, a 12-cavity mold, two vertical hydraulic actuators, and a water-spray cleaning subsystem in a four-stage operating cycle. A retrospective concept-appraisal matrix compares this architecture with fixed automated and mobile manual concepts; equal weighting and one-at-a-time ±25% weight variations preserve the ML12’s highest internal score, without establishing stakeholder preference or empirical superiority. The evidence base also comprises sequential daily production logs: ten days of traditional manual molding followed by ten days of ML12-assisted molding. Mean gross green-brick output was 720 ± 86 bricks/day in the traditional period and 1495 ± 16 bricks/day in the ML12 period; corresponding descriptive throughputs were 86.5 and 186.9 bricks/h. A rejection-rate sensitivity analysis shows that, if traditional production had no rejects, ML12 conforming output would equal the traditional gross mean at a 51.8% ML12 rejection rate; this quantity boundary is not an estimate of quality or economic break-even. A preliminary linear-static finite-element case for a reconstructed frame returned a maximum von Mises stress of 112.3 MPa, 1.82 mm resultant displacement, and a minimum elastic safety factor of 2.23 on the reported medium mesh; the result is limited to the specified 1.0 kN load case and is not structural certification of the complete machine. Because the operational comparison was non-randomized and did not control staffing, operators, clay batch, moisture, weather, energy use, or rejection rate, the observed difference cannot be attributed exclusively to the machine. The results establish the machine architecture, an operational signal, and a bounded preliminary frame response, but not brick quality, ergonomic benefit, full structural safety, environmental benefit, or commercial return.

Measuring solar irradiance helps maximize efficiency in photovoltaic power plants. Devices for detecting solar irradiance, such as pyranometers, are difficult to calibrate and extremely expensive. Given these limitations, they are rarely used in photovoltaic power plants. This study explores the feasibility of monitoring solar radiation using an FPGA and low-cost, ambient light and power sensors. The monitoring of irradiance and illuminance was graphed and stored in a software application. Unlike traditional monitoring systems, this approach directly measured the electrical power generated by the cell as a proxy for solar irradiance. To validate the accuracy of the system, the measurements obtained were compared with a professional reference pyranometer (INIFAP). Linear regression analysis showed a linear correlation (R²) of 0.8115 between the system measurements and the high-cost reference pyranometer. In addition, accuracy was quantified using the Root Mean Square Error (RMSE) of 21.68 W/m². The regression slope showed an average photovoltaic conversion efficiency of 15.44% during the test period, validating the system as an accurate, linear, and reliable tool for monitoring irradiance.

Smart lighting systems based on the Digital Addressable Lighting Interface (DALI) protocol are the most suitable for street lighting systems, allowing digital lighting control operations. Unfortunately, the microcontrollers, which are commonly used in the Wireless Sensor Network nodes to control the lamps, do not implement this protocol. The DALI protocol implemented by software in the microcontroller consumes hardware resources (timers), processing time and requires a precise temporal analysis of the application, due to the strict bit times and the Manchester coding that it uses. In this work, the design of a bridge is proposed to free the microcontroller from the implementation of the DALI protocol. The novelty of this work is the implementation of the DALI Bridge in a low-cost Field-Programmable Gate Array (FPGA) with low power consumption. The bridge has been described in the hardware description language following the 1076-93 and 1076.3-97 standards, to guarantee its portability. The results of the synthesis show that a minimum amount of logical and routing resources is used, that the power consumption is in the order of tens of mW, that it has a very small latency time and that it supports a high operating frequency, which allows adding new functions. Its operation is verified by implementing a wireless sensor node using an FPGA of the Lattice Semiconductor iCE40 family.

The objective of this chapter is to identify web accessibility problems in order to fulfill the design guidelines. According to the proposal, accessibility is assessed through easy checks of the implementation of the social engineering educational platform. As a first phase, the developer carries out this evaluation and his results are analyzed. The second phase solves the identified problems or at least tries to give them a solution implementing a redesign on the platform; in the same way, the results are analyzed. In the third phase, a proposal is made of the improvements that can be introduced in the redesign of the user interface in a way that best complies with the web accessibility. The problem identified shows the difficulty of implementing the accessibility guides and the need to propose accessibility implementation guidelines that guarantee their compliance.