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Machine Learning-Based Classification of Sulfide Mineral Spectral Emission in High Temperature Processes
(Multidisciplinary Digital Publishing Institute (MDPI), 0025) Toro, Carlos; Díaz, Walter; Reyes, Gonzalo; Peña, Miguel; Caselli, Nicolás; Taramasco, Carla; Ormeño-Arriagada, Pablo; Balladares, Eduardo
Accurate classification of sulfide minerals during combustion is essential for optimizing pyrometallurgical processes such as flash smelting, where efficient combustion impacts resource utilization, energy efficiency, and emission control. This study presents a deep learning-based approach for classifying visible and near-infrared (VIS-NIR) emission spectra from the combustion of high-grade sulfide minerals. A one-dimensional convolutional neural network (1D-CNN) was developed and trained on experimentally acquired spectral data, achieving a balanced accuracy score of 99.0% in a test set. The optimized deep learning model outperformed conventional machine learning methods, highlighting the effectiveness of deep learning for spectral analysis in high-temperature environments. In addition, Gradient-weighted Class Activation Mapping (Grad-CAM) was applied to enhance model interpretability and identify key spectral regions contributing to classification decisions. The results demonstrated that the model successfully distinguished spectral features associated with different mineral species, offering insights into combustion dynamics. These findings support the potential integration of deep learning for real-time spectral monitoring in industrial flash smelting operations, thereby enabling more precise process control and decision-making. © 2025 by the authors.
Applying Machine Learning Sampling Techniques to Address Data Imbalance in a Chilean COVID-19 Symptoms and Comorbidities Dataset
(Multidisciplinary Digital Publishing Institute (MDPI), 2025-02) Ormeño-Arriagada, Pablo; Márquez, Gastón; Araya, David; Rimassa, Carla; Taramasco, Carla
Reliably detecting COVID-19 is critical for diagnosis and disease control. However, imbalanced data in medical datasets pose significant challenges for machine learning models, leading to bias and poor generalization. The dataset obtained from the EPIVIGILA system and the Chilean Epidemiological Surveillance Process contains information on over 6,000,000 patients, but, like many current datasets, it suffers from class imbalance. To address this issue, we applied various machine learning algorithms, both with and without sampling methods, and compared them using different classification and diagnostic metrics such as precision, sensitivity, specificity, likelihood ratio positive, and diagnostic odds ratio. Our results showed that applying sampling methods to this dataset improved the metric values and contributed to models with better generalization. Effectively managing imbalanced data is crucial for reliable COVID-19 diagnosis. This study enhances the understanding of how machine learning techniques can improve diagnostic reliability and contribute to better patient outcomes. © 2024 by the authors.
Allocation of Strategic Positions for Storage of Meat Products Requiring Cold Chain
(Multidisciplinary Digital Publishing Institute (MDPI), 2025-03) Herrera, Fernando J. Olier; Berrio, Carlos A. Porto; Herrera-Vidal, Germán; Adarme, Wilson; Linfati, Rodrigo; Gatica, Gustavo; Coronado-Hernández, Jairo R.
The objective of this study is to optimize the allocation of storage positions in a cold storage facility for meat products, guaranteeing compliance with the cold chain and improving logistical efficiency. To this end, a mathematical optimization model was designed and applied that strategically assigns storage locations based on inventory turnover and product accessibility. Different configurations were evaluated based on space utilization criteria, access times, and operating costs. Based on the analyzed data, the findings indicate a significant improvement in storage efficiency, with utilization reaching 71.87% in U1, U2, U3, and UE units and 75% in C1 and C2 units. In addition, the new distribution minimized handling times and reduced the risk of product spoilage. Based on these findings, it is demonstrated that optimizing cold storage distribution not only improves inventory management and operational logistics but also contributes to system sustainability by reducing waste and costs associated with inefficient handling of perishable products. © 2025 by the authors.
Active learning in engineering education: Insights from a faculty development program in higher education
(Eurasia Journal of Mathematics, Science and Technology Education, Volume 21, Issue 22025 Article number em2585, 2025) Dominguez, Angeles; Truyol, Maria Elena; Quezada-Espinoza, Monica; Calderon, Juan Felipe; Zavala, Genaro
This study examines the enhancement of teaching practices within the school of engineering at a private Chilean university that emerged from a collective reflection of ideas/actions on the strengths, weaknesses, opportunities, and threats in the implementation of a professional development program in the school of engineering. It investigates factors influencing the efficacy of student-centered learning and teaching through the application of the World Café methodology among faculty participants in a structured training program aligned with institutional educational policies. Emphasizing long-term sustainability, the findings underscore the presence of motivated instructors committed to ongoing improvement, bolstered by comprehensive continuing education opportunities provided by the university. Despite notable progress, challenges such as limited financial resources and the imperative for strategic institutional commitment are acknowledged. Crucially, successful educational initiatives hinge on robust collaboration and dialogue between faculty and administration. The study advocates for tailored faculty training essential for adapting to evolving educational and technological landscapes. It concludes by highlighting the broader implications for engineering and STEM disciplines, advocating for a cohesive teaching community poised to meet future educational challenges. © (2025), (Modestum LTD). All rights reserved
Continuing education of academic women in STEM: perspectives on mentoring and professional roles
(Frontiers in Education, Volume 102025 Article number 1473331, 2025) García-Silva, Erika; Perez-Suarez, Sonia; Zavala-Parrales, Ana; Meléndez-Anzures, Frank; Dominguez, Angeles
Despite ongoing efforts towards gender equity, the gender gap in STEM (Science, Technology, Engineering, and Mathematics) remains significant today. This article explores the motivations and perceptions of women in different professional roles within STEM fields regarding the importance of mentoring in fostering interest and participation in STEM careers, thus contributing to continuing engineering education. Based on qualitative data from 19 semi-structured interviews with women in managerial, research, teaching, and external academic and professional roles, the study delves into their motivations for pursuing STEM careers, their interest in promoting diversity, and the role of mentoring in supporting their professional development. The thematic analysis results are grouped into a hierarchical structure comprising one meta-theme, four primary, and six subthemes. The participants emphasized that their primary motivation for STEM involvement was contributing to society and promoting economic growth. Additionally, they advocated for greater diversity and challenged traditional gender roles in these areas. The participants highlighted the importance of closing the gender gap and recognizing the capabilities and new perspectives that women brought. Although these women faced obstacles such as glass ceilings, having a mentorship opportunity was identified as a critical tool for women’s empowerment and training. The insights contribute to advancing strategies for promoting gender equity and diversity in STEM fields, with implications for researchers, universities, and organizations seeking to support women’s participation and advancement in STEM careers. Further research is recommended to explore the perspectives of women in other roles and the effectiveness of mentoring programs in fostering gender diversity in STEM. Copyright © 2025 García-Silva, Perez-Suarez, Zavala-Parrales, Meléndez-Anzures and Dominguez.
Fuzzy Classification of Mineral Resources: Moving Toward Overlapping Categories to Account for Geological, Economic, Metallurgical, Environmental, and Operational Criteria
(Geological uncertainty; Geostatistical simulation; Mineral resource classification; Overlapping categories; Reporting standards, 0025) Mery, Nadia; Maleki, Mohammad; País, Gabriel; Molina, Andrés; Cáceres, Alejandro; Emery, Xavier
A pivotal aspect in the evaluation of mining projects is the classification of mineral resources, which directly influences the definition of mineral reserves and significantly impacts mine planning and operational stages. However, the current classification methodologies often need specificity regarding the methods and parameters employed and heavily rely on the qualified/competent person’s judgment. This study addresses these gaps by proposing a pioneering fuzzy approach to assess grade and tonnage uncertainties. By allowing for overlapping resource categories and directly incorporating economic, geological, metallurgical, environmental, and operational criteria, we aim to provide tools for decision-making and for the final classification and public disclosure of mineral resources and reserves. We demonstrate the potential of our proposed methodology through an application to an iron ore deposit case study and through a detailed discussion on its uses, contributions, strengths, weaknesses, and on whether it complies with international reporting codes. © The Author(s) 2025.
Submarine landforms and seismic facies in Börgen Bay, Anvers Island: Imprints of the past glacial behaviour and climate influence in the Western Antarctic Peninsula
(Elsevier B.V., 2021-09) Rodrigo, Cristian; Herbstaedt, Rudolph
The glacimarine processes in the Western Antarctic Peninsula have been intensified since the “Little Ice Age”. These have been recorded in the distribution and shape of glacial submarine landforms and glacial sub-bottom stratigraphy. In this study, the dominant factors of the past ice flow behaviour and glacimarine sedimentary processes in Börgen Bay, Anvers Island, are identified and analyzed. The results indicate that the outer bay linear features are associable to the past ice flow during the Last Glacial Maximum. After that, a general deglaciation period occurred, with some readvances and short stillstand, interpreted by the presence of moraines and small transverse ridges. The presence of “pinning points” on the coast, could affect the glacier movements and favour the generation of moraines. Differences in the ice flow behaviour between the bay arms, are due to factors such as bathymetry, and the size of the drainage basin and glacier front. Main sedimentary processes are ice-rafting and subglacial flows, marked by chaotic seismic facies, and gravity flows identified by monticulated and transparent seismic facies, and also sediment plumes contribution, creating laminated facies in the proximal area basins. Those sedimentary mechanisms and landforms agree with a wet polar climate, but some of them would indicate a warmer climate shifting, that is necessary to prove with systematic future measurements. © 2021 Elsevier B.V. and NIPR
A grey system approach for estimating the hölderian regularity with an application to algerian well log data
(MDPI AG, 2021-09) Gaci, Said; Nicolis, Orietta
The Hölderian regularity is an important mathematical feature of a signal, connected with the physical nature of the measured parameter. Many algorithms have been proposed in lit-erature for estimating the local Hölder exponent value, but all of them lead to biased estimates. This paper attempts to apply the grey system theory (GST) on the raw signal for improving the accuracy of Hölderian regularity estimation. First, synthetic logs data are generated by the succes-sive random additions (SRA) method with different types of Hölder functions. The application on these simulated signals shows that the Hölder functions estimated by the GST are more precise than those derived from the raw data. Additionally, noisy signals are considered for the same ex-periment, and more accurate regularity is obtained using signals processed using GST. Second, the proposed technique is implemented on well log data measured at an Algerian exploration bore-hole. It is demonstrated that the regularity determined from the well logs analyzed by the GST is more reliable than that inferred from the raw data. In addition, the obtained Hölder functions al-most reflect the lithological discontinuities encountered by the well. To conclude, the GST is a powerful tool for enhancing the estimation of the Hölderian regularity of signals. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Fuzzy Classification of Mineral Resources: Moving Toward Overlapping Categories to Account for Geological, Economic, Metallurgical, Environmental, and Operational Criteria
(Springer, 0025) Mery, Nadia; Maleki, Mohammad; País, Gabriel; Molina, Andrés; Cáceres, Alejandro; Emery, Xavier
A pivotal aspect in the evaluation of mining projects is the classification of mineral resources, which directly influences the definition of mineral reserves and significantly impacts mine planning and operational stages. However, the current classification methodologies often need specificity regarding the methods and parameters employed and heavily rely on the qualified/competent person’s judgment. This study addresses these gaps by proposing a pioneering fuzzy approach to assess grade and tonnage uncertainties. By allowing for overlapping resource categories and directly incorporating economic, geological, metallurgical, environmental, and operational criteria, we aim to provide tools for decision-making and for the final classification and public disclosure of mineral resources and reserves. We demonstrate the potential of our proposed methodology through an application to an iron ore deposit case study and through a detailed discussion on its uses, contributions, strengths, weaknesses, and on whether it complies with international reporting codes. © The Author(s) 2025.
Predicción de casos de COVID-19 y modelo de localización asignación de bases y ambulancias considerando factores de vulnerabilidad
(Universidad de Tarapaca, 2021-09) Calderón, Samantha Reid; Nicolis, Orietta; Peralta, Billy; Menares, Franco
En este trabajo se aborda el problema de localización estratégica de bases y ambulancias, considerando la cantidad de habitantes y un ponderador de vulnerabilidad, confirmado por elementos socioeconómicos y epidemiológicos. A tal fin, se utiliza un modelo lineal generalizado (GLM) para la predicción de casos de COVID-19 a nivel comunal y un modelo de optimización matemático de localización y asignación que maximiza la cobertura de atención a la población. La metodología se aplica en la región Metropolitana en Chile, analizando la situación actual de la institución del Servicio de Atención Médico de Urgencias (SAMU), encargada de la gestión de ambulancias en la región. Asimismo, se ocupará el Índice de Prioridad Social (IPS) como factor socioeconómico y la cantidad de pacientes confirmados por COVID19 desde el 30 de Marzo hasta el 12 de Junio del 2020. En los resultados, para el modelo de predicción, se obtuvo una proyección coherente para una semana de estudio, con errores residuales aceptables. En cuanto al modelo de optimización, se comprueba la acción del ponderador de vulnerabilidad, tanto para una reasignación de ambulancias en el sistema como para una incorporación de bases y/o ambulancias, dando resultados en tiempos de cómputo aceptables.
The ages, metallicities, and alpha element enhancements of globular clusters in the elliptical NGC 5128: A homogeneous spectroscopic study with gemini/gemini multi-object spectrograph
(Institute of Physics Publishing, 2010) Woodley, Kristin A.; Harris, William E.; Puzia, Thomas H.; Gómez, Matías; Harris, Gretchen L. H.; Geisler, Doug
We present new integrated light spectroscopy of globular clusters (GCs) in NGC 5128, a nearby giant elliptical galaxy less than 4 Mpc away, in order to measure radial velocities and derive ages, metallicities, and alpha-element abundance ratios. Using the Gemini South 8 meter telescope with the instrument Gemini Multi-Object Spectrograph, we obtained spectroscopy in the range of ∼ 3400-5700 for 72 GCs with a signal-to-noise ratio greater than 30Å -1; and we have also discovered 35 new GCs within NGC 5128 from our radial velocity measurements. We measured and compared the Lick indices from HδA through Fe5406 with the single stellar population models of Thomas etal. in order to derive age, metallicity, and [α/Fe] values. We also measure Lick indices for 41 Milky Way GCs from Puzia etal. and Schiavon etal. with the same methodology for direct comparison. Our results show that 68% of the NGC 5128 GCs have old ages (>8 Gyr), 14% have intermediate ages (5-8 Gyr), and 18% have young ages (<5 Gyr). However, when we look at the metallicity of the GCs as a function of age, we find 92% of metal-poor GCs and 56% of metal-rich GCs in NGC 5128 have ages >8 Gyr, indicating that the majority of both metallicity subpopulations of GCs formed earlier, with a significant population of young and metal-rich GCs forming later. Our metallicity distribution function generated directly from spectroscopic Lick indices is clearly bimodal, as is the color distribution of the same set of GCs. Thus, the metallicity bimodality is real and not an artifact of the color to metallicity conversion. However, the metallicity distribution function obtained from comparison with the single stellar population models is consistent with a unimodal, bimodal, or multimodal shape. The [α/Fe] values are supersolar with a mean value of 0.14 ± 0.04, indicating a fast formation timescale. However, the GCs in NGC 5128 are not as [α/Fe] enhanced as the Milky Way GCs also examined in this study. Our measured indices also indicate that the GCs in NGC 5128 may have a slight overabundance in nitrogen and a wider range of calcium strength compared to the Milky Way GCs. Our results support a rapid, early formation of the GC system in NGC 5128, with subsequent major accretion and/or GC and star-forming events in more recent times. © 2010. The American Astronomical Society.
Autonomous Mobile Station for Artificial Intelligence Monitoring of Mining Equipment and Risks
(Multidisciplinary Digital Publishing Institute (MDPI), 0025) Cerna, Gabriel País; Herrera-Vidal, Germán; Coronado-Hernández, Jairo R
Artificial intelligence in the mining industry is key to improving safety, optimizing resources, and ensuring sustainable operations in complex environments. The main objective of this research is to develop an autonomous mobile station equipped with artificial vision and artificial intelligence to identify and track equipment, people, and animals in critical areas of mining operations, issuing real-time alerts to reduce occupational risks and improve operational control. The research is applied with an experimental approach, designed to validate the effectiveness of the proposed system in real open-pit mining environments. The proposed methodology consisted of five stages: (i) Selection of data collection equipment, (ii) Definition of the positioning scheme, (iii) Incorporation of the communication system, (iv) Data processing and transformation, and (v) Equipment identification and tracking. The results showed an average accuracy of 98% in the validation and 95% in the test, achieving perfect performance (100%) in key categories such as excavators and drills, highlighting the potential of this technology to transform mining towards safer and more efficient standards. © 2025 by the authors.
Improvement of thermal stability of highly active species on SiO2supported copper-ceria catalysts
(Royal Society of Chemistry, 2021-09-28) Aguila, Gonzalo; Calle, Rafael; Guerrero, Sichem; Baeza, Patricio; Araya, Paulo
CuO-CeO2/SiO2 catalysts lose activity when they are calcined at 600 °C and temperatures above. This loss of activity was related to a decrease in the amount of highly dispersed Cu species interacting with Ce (CuO-CeO2 interface) over the SiO2 support. These species are highly active in CO oxidation, so this reaction was selected to conduct this study. In order to avoid the activity loss in CuO-CeO2/SiO2 catalysts, the effect of high Ce loads (8, 16, 24, and 36%) on the thermal stability of these catalysts was studied. The results reveal that when increasing calcination temperature from 500 to 700 °C, the catalysts with Ce load equal to or higher than 24% increase the formation of highly dispersed Cu interacting with Ce and therefore the activity (90% of CO conversion at 120 °C). In catalysts with Ce load below 24%, Cu species agglomerate and decrease the activity (less than 5% of CO conversion at 120 °C). This journal is © The Royal Society of Chemistry.
Stochastic approach to heterogeneity in short-time announcement effects on the Chilean stock market indexes within 2016-2019
(Taylor and Francis Ltd., 2023) Stehlík, Milan; Leal, Danilo; Kiseľák, Jozef; Leers, Joshua; Střelec, Luboš; Fuders, Felix
We aim to examine stock market returns before and after key events in the U.S. Sino trades between 2016 and 2019. The study tracks Cumulative Abnormal Returns (CAR) of the Índice de Precio Selectivo de Acciones (IPSA or S&P/CLX IPSA is a Chilean stock market index) for 26 important events throughout this time period. By testing for both directions and significance of market reaction to said events this study aims to clarify if these events and policy announcements were sufficient to influence local equity markets, and in which direction. A simple analysis of CAR showed 16 negative reactions and 10 Positive reactions. An estimated 13 billion USD in market capitalization was lost as a result. Of the 26 events studied 18 were found to produce statistically significant reactions and 8 did not. The IPSA’s reaction to the significant events was mixed with 11 negative reactions and 7 positive reactions. We also checked for the normality of the distribution by robust normality tests and expected returns possess significant asymmetry and above-normal kurtosis. As such on aggregate it can be concluded that Chilean capital markets reacted negatively to the U.S. Sino trade war. We model IPSA in the period 2016–2022, where we can observe qualitative differences before and after 2019. To the best knowledge of the authors, the model of IPSA in this article is the first attempt in this direction. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.
Neogene Patagonian magmatism between the rupture of the Farallon plate and the Chile Ridge subduction
(Elsevier Ltd, 2021-10) Ramírez de Arellano, Cristóbal; Calderón, Mauricio; Rivera, Huber; Valenzuela, Mauricio; Fanning, C. Mark; Paredes, Eliot
Based on chemical composition and timing of late Paleogene and Neogene igneous rocks in southern Patagonia, six igneous suites are identified and correlated with subduction processes during the approaching and subduction of active oceanic ridges. Neogene magmatism took place after a period of decreased sub-alkaline magmatism during late Paleogene (LPg Suite). Early Miocene calc-alkaline rocks mark the reactivation of magmatism after subduction acceleration (Suite 1). These rocks are located at ca. 200 km from the trench and are typical products of continental magmatic arcs, where focused metasomatism of the mantle wedge results on high-degree of partial melting (>15%) in a restricted area expressed as a narrow volcanic arc. Contrarily, transitional sub-alkaline to alkaline rocks (Suite 2) were formed during the approaching of the Chile spreading ridge and the subduction of hot oceanic lithosphere (prior to the development of a slab window), where metasomatism encompassed a broader region of the mantle wedge, resulting in lower degrees of partial melting (<15%) and a wider volcanic arc, at ca 200–450 km from the trench. Intermediate igneous rocks with high Sr/Y ratio (Suite 3), located either within a magmatic arc setting, at ca. 270 km from the trench, or in the forearc region (less than 20 km from the trench), were formed during the subduction of the trailing edge of the Nazca plate. Alkaline basalts (Suite 4) are widely distributed, between 220 and 630 km from the trench. They are temporally and spatially related to a slab window generated after the subduction of the Chile Ridge. Andesites with high Sr/Y ratio (Suite 5) from the Quaternary Austral Volcanic Zone, at ca. 160 from the trench, were formed during the subduction of the leading edge of the Antarctica plate. The time and spatial distribution of these suites allow us to propose that the diverse chemical composition of Neogene igneous rocks in southern Patagonia was controlled by varying degrees of metasomatism and partial mantle melting controlled by the thermal structure of the mantle wedge prior, during and after the subduction of an active oceanic spreading ridge. Particularly, the chemical variability and the spatial distribution of Suite 2, which is not common in other magmatic arcs, could be used as a proxy for a warm mantle wedge structure. © 2021 Elsevier Ltd
Chaotic Binarization Schemes for Solving Combinatorial Optimization Problems Using Continuous Metaheuristics
(Multidisciplinary Digital Publishing Institute (MDPI), 0024) Cisternas-Caneo, Felipe; Crawford, Broderick; Soto, Ricardo; Giachetti, Giovanni; Paz, Álex; Peña Fritz, Alvaro
Chaotic maps are sources of randomness formed by a set of rules and chaotic variables. They have been incorporated into metaheuristics because they improve the balance of exploration and exploitation, and with this, they allow one to obtain better results. In the present work, chaotic maps are used to modify the behavior of the binarization rules that allow continuous metaheuristics to solve binary combinatorial optimization problems. In particular, seven different chaotic maps, three different binarization rules, and three continuous metaheuristics are used, which are the Sine Cosine Algorithm, Grey Wolf Optimizer, and Whale Optimization Algorithm. A classic combinatorial optimization problem is solved: the 0-1 Knapsack Problem. Experimental results indicate that chaotic maps have an impact on the binarization rule, leading to better results. Specifically, experiments incorporating the standard binarization rule and the complement binarization rule performed better than experiments incorporating the elitist binarization rule. The experiment with the best results was STD_TENT, which uses the standard binarization rule and the tent chaotic map. © 2024 by the authors.
Measuring Complexity in Manufacturing: Integrating Entropic Methods, Programming and Simulation
(Entropy, Volume 27, Issue 11 January 2025 Article number 50, 2025) Herrera-Vidal, Germán; Coronado-Hernández, Jairo; Derpich-Contreras, Ivan; Martínez Paredes, Breezy P.; Gatica, Gustavo
This research addresses complexity in manufacturing systems from an entropic perspective for production improvement. The main objective is to develop and validate a methodology that develops an entropic metric of complexity in an integral way in production environments, through simulation and programming techniques. The methodological proposal is composed of six stages: (i) Case study, (ii) Hypothesis formulation, (iii) Discrete event simulation, (iv) Measurement of entropic complexity by applying Shannon’s information theory, (v) Entropy analysis, and (vi) Statistical analysis by ANOVA. The results confirm that factors such as production sequence and product volume significantly influence the structural complexity of the workstations, with station A being less complex (0.4154 to 0.9913 bits) compared to stations B and C, which reached up to 2.2084 bits. This analysis has shown that optimizing production scheduling can reduce bottlenecks and improve system efficiency. Furthermore, the developed methodology, validated in a case study of the metalworking sector, provides a quantitative framework that combines discrete event simulation and robust statistical analysis, offering an effective tool to anticipate and manage complexity in production. In synthesis, this research presents an innovative methodology to measure static and dynamic complexity in manufacturing systems, with practical application to improve efficiency and competitiveness in the industrial sector. © 2025 by the authors
Visual-aid positioning using point cloud compression and RGB-D cameras for robotic manipulators
(Ingeniare, Volume 312023 Article number 16, 2023) Cisternas Velásquez, Estefan Iván; Del Río Caldumbide, Julio Andrés; Prado Romo, Álvaro Javier; Menéndez Granizo, Oswaldo Aníbal
Over the last decade, optimization of a massive set of industrial tasks has been achieved by taking advantage of repeatability and precision of robotic arms. While the new era of robotic arms introduces high-tech tools to fix positioning and tracking issues, upgrading older units is a significant challenge due to hardware incompatibilities, outdated mechanisms, and operation restrictions. This work introduces a new visual system to determine the position of a robotic arm using a two-stereo-cameras array. The visual-positioning system estimates the position of the end-effector using an inverse model of the robot and the full point cloud acquired with the stereo cameras. An Iterative Point Cloud algorithm merges the partial point clouds of each depth sensor, and with a yellow color detector, the algorithm extracts the Region of Interest (ROI). Experimental results show that the proposed device can estimate the relative position of the end-effector with respect to the robotic arm base with errors in the longitudinal, lateral, and vertical positions of around 19.6%, 15.7% and 9.2%, respectively. © 2023, Universidad de Tarapaca. All rights reserved
CANVAS: una nueva etiología de la ataxia del adulto. La asociación con tos orienta al diagnóstico. Comunicación de 2 pacientes
(Sociedad Medica de Santiago, 2023-04) Miranda, Marcelo C.; Diaz, Mario; Hughes, Ricardo G.; Nakousi, Nicole C.; Campero, Mario S.
Presentamos dos pacientes no relacionados con ataxia cerebelosa de inicio tardío asociada con neuropatía y tos seca de larga data. Un paciente tenía dos hermanos afectados con neuropatía sensorial y tos. Ambos probandos tuvieron investigaciones extensas que incluyó pruebas genéticas negativas para las ataxias más comunes, así como pruebas paraneoplásicas y otras causas inmunológicas. Ambos pacientes mostraron una expansión intrónica anormal en el pentanucleótido AAGGG del gen RFC1. Esta etiología se informa como causa frecuente de ataxia de inicio en adultos; la presencia de tos puede conducir al diagnóstico correcto.
Exact formulation and analysis for the bi-objective insular traveling salesman problem
(MDPI, 2021-11-01) Miranda-Gonzalez, Pablo A.; Maturana-Ross, Javier; Blazquez, Carola A.; Cabrera-Guerrero, Guillermo
This paper aims at studying the Bi-Objective Insular Traveling Salesman Problem (BO-InTSP), which searches for a set of efficient, single visit sequences to collect (or distribute) freight from a set of islands. In this problem, the selection of ports (nodes) to be visited at each island, along with the associated port visit sequence, are optimized simultaneously, while the maritime transportation costs and the ground transportation costs inside the islands are minimized with a bi-objective perspective. This approach is employed since these costs are of a conflictive nature. A previous Approximated Formulation of the BO-InTSP relies on aggregating the actual demand locations within each island in a certain number of centroids for computing the ground transportation costs. Conversely, this paper proposes and develops a novel Exact Formulation for the problem based on the actual demand locations, instead of aggregating the demand inside the islands. Additionally, a systematic evaluation approach is developed to compare the two alternative formulations with different levels of demand aggregation inside the islands, considering the bi-objective nature of the problem. The results reveal that the novel Exact Formulation significantly outperforms the previous aggregated approach in terms of the solutions quality and computational resources. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

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