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The localization of nodes plays a fundamental role in Wireless Sensor and Actors Networks (WSAN) identifying geographically where an event occurred, which facilitates timely response to this action. This article presents a performance evaluation of multi-hop localization range-free algorithms used in WSAN, such as Distance Vector Hop (DV-Hop), Improved DV-Hop (IDV-Hop), and the Weighted DV-Hop (WDV-Hop). In addition, we propose a new localization algorithm, merging WDV-Hop, with the weighted hyperbolic localization algorithm (WH), which includes weights to the correlation matrix of the estimated distances between the node of interest (NOI) and the reference nodes (RN) in order to improve accuracy and precision. As performance metrics, the accuracy, precision, and computational complexity are evaluated. The algorithms are evaluated in three scenarios where all nodes are randomly distributed in a given area, varying the number of RNs, the density of nodes in the network, and radio coverage of the nodes. The results show that in networks with 100 nodes, WDV-Hop outperforms the DV-Hop and IDV-Hop even if the number of RNs is reduced to 10. Moreover, our proposal shows an improvement in terms of accuracy and precision at the cost of increased computational complexity, specifically in the algorithm execution time, but without affecting the hardware cost or power consumption.

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ObjectiveTo assess whether an intervention based on nurse home visits including alert buttons (NV+AB) is effective in reducing frailty compared to nurse home visits alone (NV-only) and usual care (control group) for older adults.DesignUnblinded, randomized, controlled trial.SettingInsured population covered by the Mexican Social Security Institute living in the city of Ensenada, Baja California, Mexico.ParticipantsPatients were aged over 60 years with a frailty index score higher than 0.14.InterventionAfter screening and informed consent, participants were allocated randomly to the control, NV+AB, or NV-only groups.MeasurementsThe primary outcome was the frailty score 9 months later. Quality of life, depression, comorbidities, health status, and health service utilization were also considered.ResultsThe framing sample included 819 patients. Of those, 591 were not located because they did not have a landline/telephone (341 patients), they had died (107), they were ill (50), or they were not currently living in the city (28). A screening interview was applied to 228 participants, and 57 had a score ≤0.14, 171 had ≥0.14, and 16 refused to complete the baseline questionnaire. A home visit was scheduled for 155 patients. However, 22 did not complete the baseline questionnaire. The final 133 subjects were randomized into the NV+AB (n = 45), NV-only (n = 44), and control (n = 44) groups. There were no statistically significant differences in the baseline characteristics of the groups. The mean age overall was 76.3 years (standard deviation 4.7) and 45% were men. At the baseline, 61.65% were classified as frail. At end of follow-up the adjusted prevalence of frailty in NV+AB group was 23.3% versus 58.3% in the control group.Conclusion:An intervention based on NV+AB seems to have a positive effect on frailty scores.

Se estudia las características principales del comportamiento del consumidor en plataformas de compra en línea en el estado sur de Sonora. Esto se hace mediante un estudio cualitativo basado en la metodología de la Teoría Fundamentada. La idea principal es identificar y categorizar variables sobre la compra en línea basándose en factores relevantes como la motivación de compra, preferencias, hábitos de consumo y patrones de compra. Para llevar a cabo el estudio, se realizaron entrevistas semi-estructuradas a consumidores del estado sur de Sonora, México, con experiencia en compras en línea. De esta manera, al concluir el análisis, se obtuvieron tres categorías principales: motivación de compra, experiencias del consumidor y comportamiento. También se identificaron una serie de variables que tienen mayor influencia en las preferencias, decisión de compra y el patrón de compra en los consumidores. Los resultados obtenidos proporcionan información de utilidad para la creación de estrategias que permitan tomar decisiones efectivas mediante su aplicación en el diseño de plataformas en línea ofreciendo un servicio personalizado a los consumidores.