Valencia-Aragón, Kevin
Preferred name
Valencia-Aragón, Kevin
Main Affiliation
Quito
13 results
Now showing 1 - 10 of 13
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Item type:Publication, Low-Cost Non-Wearable Fall Detection System Implemented on a Single Board Computer for People in Need of Care(2024); This work aims at proposing an affordable, non-wearable system to detect falls of people in need of care. The proposal uses artificial vision based on deep learning techniques implemented on a Raspberry Pi4 4GB RAM with a High-Definition IR-CUT camera. The CNN architecture classifies detected people into five classes: fallen, crouching, sitting, standing, and lying down. When a fall is detected, the system sends an alert notification to mobile devices through the Telegram instant messaging platform. The system was evaluated considering real daily indoor activities under different conditions: outfit, lightning, and distance from camera. Results show a good trade-off between performance and cost of the system. Obtained performance metrics are: precision of 96.4%, specificity of 96.6%, accuracy of 94.8%, and sensitivity of 93.1%. Regarding privacy concerns, even though this system uses a camera, the video is not recorded or monitored by anyone, and pictures are only sent in case of fall detection. This work can contribute to reducing the fatal consequences of falls in people in need of care by providing them with prompt attention. Such a low-cost solution would be desirable, particularly in developing countries with limited or no medical alert systems and few resources.11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Environmental Patterns of Phytoplankton Community Composition Across Lentic and Lotic Systems in Ecuador(2026); Phytoplankton are key indicators of water quality and low-cost tools for freshwater monitoring, yet their diversity and ecological drivers remain poorly documented in the Tropical Andes. This study provides the first national-scale, multi-ecosystem assessment of net phytoplanktonic communities (including microalgae and cyanobacteria), across Ecuador, integrating physicochemical, multivariate, and geospatial analyses. Eighteen lakes and rivers from three biogeographic regions and a wide altitudinal gradient were surveyed, yielding 129 taxa, 77 identified at species level, the most comprehensive checklist reported to date for Ecuador. Community structure showed a clear lentic–lotic differentiation driven by hydrodynamic contrasts, while the absence of distance–decay patterns indicated high dispersal and environmental filtering pattern rather than spatial structuring. Anthropogenic pressure acted as a secondary gradient: pristine high-Andean lakes were dominated by desmids and diatoms, whereas agricultural and urban basins showed chlorophyte and potentially toxic cyanobacterial assemblages. Palmer’s Index detected organic pollution but underestimated eutrophication in endorheic, geochemically enriched lakes. Land-use effects presented strong basin-scale signals in lakes but weak correlations in rivers due to overriding hydromorphological constraints. These findings establish a robust spatial baseline for freshwater bioassessment in the Andes, demonstrating the value of phytoplankton as effective, low-cost indicators readily applicable to national water-quality assessment programs.8 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Kiteracy-PiFo: Technological Tool for Teaching the Rules of Grapheme-Phoneme Correspondence(2025); ; This study presents Kiteracy-PiFo, a technological tool designed to teach grapheme-phoneme correspondence to preschool students. Combining computer engineering and special education, the tool was developed to enhance Human-Computer Interaction in early literacy education. Despite challenges, including unforeseen events and technical issues, the tool was successfully implemented across schools in Cartago, Costa Rica. Statistical analysis revealed significant differences in vowel recognition between the experimental group using Kiteracy-PiFo and the control group using traditional methods, with the experimental group achieving higher results in less time. These findings suggest that integrating innovative technologies like Kiteracy-PiFo into educational practices can effectively accelerate learning in early childhood settings. However, successful implementation depends on strong pedagogical support and alignment with psychological principles to meet students’ cognitive and emotional needs.18 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Eye-Tracking and Pictograms: Improving Communication and Accessibility for Senior Adults(2024); ; Sandra Sanchez-GordonAn important factor in exploring the world around us and understanding the cognitive process of individuals is analyzing the characteristics and behavior of the eyes, as they provide reliable information. Improving communication processes with users through visual communication environments can create an accessible environment for virtual interaction. In this context, the global population is aging at a faster rate, leading to social transformation. This population segment may face challenges with language skills, health issues, psychological disorders, and traumas that can limit their ability to speak or move. The purpose of this study is to investigate whether eye-tracking, using the eye-tracking device, will enable senior adults to interact with their caregivers through a pictogram-based interface, allowing them to generate messages and communicate their needs. The research method involves the conceptual development of an experiment designed for senior adults, including the use of an eye-tracking device, calibration tests, and interface responses. This research aims to better understand and promote the importance of meeting the needs and expectations of the elderly segment.20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Microplastics in Two Tropical Andean Lakes: Contrasting Human-Impacted and Minimally Disturbed Watersheds(2026); Microplastics (MPs) are emerging contaminants in freshwater systems, yet their sources and transport pathways in tropical high-altitude lakes remain poorly understood. This study quantified and characterized MPs in two Andean lakes in Ecuador with contrasting watershed conditions: San Pablo (2672 m a.s.l.), influenced by agricultural and urban land use, and Caricocha (3724 m a.s.l.), a protected high-Andean lake. Sixteen samples per lake were collected during four field campaigns. MPs were identified using visual and morphological criteria, and classified by shape, color, and size. MP concentrations were higher in San Pablo (238 ± 32 MP m−3, mean ± SD) than in Caricocha (32 ± 10 MP m−3). Fibers dominated (87.3%), followed by fragments, while microspheres were detected only in Caricocha. MP concentrations showed positive correlations with urban-agricultural land use (ρ = 0.87, p < 0.0001) and negative correlations with natural vegetation cover (ρ = −0.87, p < 0.0001). Principal Component Analysis linked fiber abundance and small size classes (<500 µm) and anthropogenic land use, consistent with surface runoff and wastewater-associated pathways. In contrast, MPs in the protected lake may originate from long-range atmospheric deposition. These results indicate that watershed configuration and protection status shape MP inputs in high-Andean lakes.5 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Optimizing Agriculture with LoRaWAN and HCI: A Smart Approach to Sustainable Farming(2025); ; 24 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Artificial Intelligence and Assistive Technologies: A Systematic Review of Educational Applications for Disabilities(2025); ; 39 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Evaluating Signage Accessibility for Individuals with Visual Impairments: A Case Study in Ecuador(2024); ; 10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Indoor Monitoring System Based on Computer Vision for Fall Detection Oriented to Elderly Assistance(2025); 20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Optimizing Agriculture with LoRaWAN and HCI: A Smart Approach to Sustainable Farming(2025); ; 31