The Effect of Recency to Human Mobility

In recent years, we have seen scientists attempt to model and explain human dynamics and, in particular, human movement. Many aspects of our complex life are affected by human movements such as disease spread and epidemics modeling, city planning, wireless network development, and disaster relief, to name a few. Given the myriad of applications it is clear that a complete understanding of how people move in space can lead to huge benefits to our society. In most of the recent works, scientists have focused on the idea that people movements are biased towards frequently-visited locations. According to them, human movement is based on an exploration/exploitation dichotomy in which individuals choose new locations (exploration) or return to frequently-visited locations (exploitation). In this work, we focus on the concept of recency. We propose a model in which exploitation in human movement also considers recently-visited locations and not solely frequently-visited locations. We test our hypothesis against different empirical data of human mobility and show that our proposed model is able to better explain the human trajectories in these datasets

Ontologies for context-aware applications

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

Microwave Radiation Applied to the Synthesis of -butyrolactone Derivatives

Many natural products with a broad spectrum of biological effects bear the g-butyrolactone ring. Given the difficulty in isolating large amounts of butyrolactones from natural sources, interest in synthesizing structural analogs of these compounds and in studying their biological properties has increased. In this review, we summarize the main synthetic methodologies to construct γ-butyrolactone derivatives by using multicomponent processes. DOI: http://dx.doi.org/10.17807/orbital.v13i4.165

Uncovering Vegetation Changes in the Urban–Rural Interface through Semi-Automatic Methods

Barbosa, B., Rocha, J., Costa, H., & Caetano, M. (2022). Uncovering Vegetation Changes in the Urban–Rural Interface through Semi-Automatic Methods. Applied Sciences, 12(5), 1-14. [2294]. https://doi.org/10.3390/app12052294 -------------- Funding: This research was funded by Portuguese Foundation for Science and Technology, I.P. (FCT), under the framework of the Project “FORESTER—Data fusion of sensor networks and fire spread modelling for decision support in forest fire suppression” [name of funder] grant number PCIF/SSI/0102/2017. The APC was funded by the Research Unit UIDB/00295/2020 and UIDP/00295/2020.Forest fires are considered by Portuguese civil protection as one of the most serious natural disasters due to their frequency and extent. To address the problem, the Fire Forest Defense System establishes the implementation of fuel management bands to aid firefighting. The aim of this study was to develop a model capable of identifying vegetation removal in the urban–rural interface defined by law for fuel management actions. The model uses normalised difference vegetation index (NDVI) of Sentinel-2 images time series and is based on the Welch t-test to find statistically significant differences between (i) the value of the NDVI in the pixel; (ii) the mean of the NDVI in the pixels of the same land cover type in a radius of 500 m; and (iii) their difference. The model identifies a change when the t-test points for a significant difference of the NDVI value in the ‘pixel’ as comparted to the ‘difference’ but not the ‘mean’. We use a moving window limited to 60 days before and after the analysed date to reduce the phenological variations of vegetation. The model was applied in five municipalities of Portugal and the results are promising to identify the places where the management of fuel bands was not carried out. This indicates which model could be used to assist in the verification of the annual management of the fuel bands defined in the law.publishersversionpublishe

Automatic detection of vegetation cover changes in urban-rural interface areas

Barbosa, B., Rocha, J., Costa, H., & Caetano, M. (2022). Automatic detection of vegetation cover changes in urban-rural interface areas. MethodsX, 9, 1-7. [101643]. https://doi.org/10.1016/j.mex.2022.101643 ---------- This work was financed by national funds through FCT—Portuguese Foundation for Science and Technology, I.P., under the framework of the Project “FORESTER - Data fusion of sensor networks and fire spread modelling for decision support in forest fire suppression” [PCIF / SSI / 0102 / 2017] and is relative to a scientific Research Fellowship BI_27_20.The present work started from the need to streamline the process of monitoring changes in vegetation in the in urban-rural interface fuel management bands, defined by Portuguese legislation as areas where the existing biomass must be totally or partially removed. The model developed uses a time series of Sentinel 2 satellite images to search for changes in the vegetation cover in a 100 meters buffer around built-up areas. The use of satellite data allows analysing large areas and speeds up the task of identifying the places where fuel management took place and the places where there is a need to carry out such management. The objective of the proposed method is to give a script in Python language that can verify the cleanliness of vegetation in the fuel management ranges through multi-temporal analysis of satellite images.publishersversionpublishe

Optimizing high-volume ultrasonic melt degassing using synchronized kinematic translation

Ultrasonic vibration is a physical processing technique that has been gathering support as an environmentally friendly approach to degas light alloy melts. Since metallic sonotrodes promote melt inclusions due to erosion, ceramic sonotrodes have also been shown as a viable solution for ultrasonic melt degassing in industrial scales. This study shows that resonant ceramic sonotrodes are characterized by a complex low-amplitude radial eigen mode, while particle image velocimetry reveals that their efficiency depends on the angular direction. An approach based on synchronized kinematic translation was designed to optimize the degassing efficiency in ultrasonic approaches, assuring its angle with higher cavitation is always facing the center of the crucible. Results show that this approach can reach lower degassing thresholds (Hmin ¼ 0.13 ml/100 g Al) at higher degassing rates, relatively to both Argon inflation (Hmin ¼ 0.22 ml/100 g Al) and static Ultrasound (Hmin ¼ 0.18 ml/100 g Al) methods. An enhanced grain refinement further supports the hypothesis that promoting a synchronized kinematic translation enhances the ultra sonic degassing efficiency. Considering these results, this approach is suggested as a reliable route to implement efficient ultrasonic degassing techniques in industrial light alloy melt treatment.This work was supported by PTDC/EMEEME/30967/2017 and NORTE-0145-FEDER-030967, co-financed by the European Regional Development Fund (ERDF), through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under Portugal 2020, and by the Fundação para a Ciencia e a Tecnologia e FCT I.P. national funds. Also, this work was supported by Portuguese FCT, under the reference project UIDB/04436/2020 and Stimulus of Scientific Employment Application CEECIND/03991/2017

Abandono en servicios - Una revisión bibliométrica

[EN] The purpose of this article is to identify the most impactful research on customer churn and to map the conceptual and intellectual structure of its field of study. Data were collected from the WoS database, comprising 338 articles published between 1995 and 2020. Several bibliometric techniques were applied, including analysis of co-words, co-citation, bibliographic coupling, and co-authorship networks. R software and the Bibliometrix/Biblioshiny package were used to perform the analyses. The results identify the most active and influential authors, articles, and journals on the topic. More specifically, through co-citations and bibliographic coupling, it was possible to map the oldest articles (retrospective analysis) and the current research front (prospective analysis). The retrospective analysis, based on co-citations, revealed that the foundations of this research field are constructs such as quality of service, satisfaction, loyalty, and changing behaviors. The prospective analysis, performed through bibliographic coupling, revealed that current research is embedded in predictive analysis, clusters, data mining, and algorithms. The results provide robust guidance for further investigation in this field.[ES] El objetivo de este artículo es identificar las investigaciones más impactantes sobre la pérdida de clientes y trazar la estructura conceptual e intelectual de su campo de estudio. Los datos han sido recogidos de la base de datos WoS, que comprenden 338 artículos publicados entre 1995 y 2020. Varias técnicas bibliométricas fueron aplicadas, incluyendo el análisis de co-palabras, cocitaciones, acoplamiento bibliográfico y redes de coautoría. Para realizar los análisis se utilizaron el software R y el Bibliometrix/Biblioshiny. Los resultados identifican los autores, artículos y revistas más influyentes y activos sobre el tema. Más específicamente, a través de las cocitaciones y el acoplamiento bibliográfico, fue posible mapear los artículos más antiguos (análisis retrospectivo) y la investigación más actual (análisis prospectivo). El análisis retrospectivo, basado en las cocitaciones, reveló que los fundamentos de este campo de investigación son constructos como la calidad del servicio, la satisfacción, la lealtad y el cambio de comportamientos. El análisis prospectivo, realizado a través del acoplamiento bibliográfico, reveló que la investigación actual está inmersa en el análisis predictivo, los conglomerados, la minería de datos y los algoritmos. Los resultados proporcionan una sólida orientación para seguir investigando en este campo

An empirical standardized soil moisture index for agricultural drought assessment from remotely sensed data

AbstractWe propose a simple, spatially invariant and probabilistic year-round Empirical Standardized Soil Moisture Index (ESSMI) that is designed to classify soil moisture anomalies from harmonized multi-satellite surface data into categories of agricultural drought intensity. The ESSMI is computed by fitting a nonparametric empirical probability density function (ePDF) to historical time-series of soil moisture observations and then transforming it into a normal distribution with a mean of zero and standard deviation of one. Negative standard normal values indicate dry soil conditions, whereas positive values indicate wet soil conditions. Drought intensity is defined as the number of negative standard deviations between the observed soil moisture value and the respective normal climatological conditions. To evaluate the performance of the ESSMI, we fitted the ePDF to the Essential Climate Variable Soil Moisture (ECV SM) v02.0 data values collected in the period between January 1981 and December 2010 at South–Central America, and compared the root-mean-square-errors (RMSE) of residuals with those of beta and normal probability density functions (bPDF and nPDF, respectively). Goodness-of-fit results attained with time-series of ECV SM values averaged at monthly, seasonal, half-yearly and yearly timescales suggest that the ePDF provides triggers of agricultural drought onset and intensity that are more accurate and precise than the bPDF and nPDF. Furthermore, by accurately mapping the occurrence of major drought events over the last three decades, the ESSMI proved to be spatio-temporal consistent and the ECV SM data to provide a well calibrated and homogenized soil moisture climatology for the region. Maize, soybean and wheat crop yields in the region are highly correlated (r>0.82) with cumulative ESSMI values computed during the months of critical crop growing, indicating that the nonparametric index of soil moisture anomalies can be used for agricultural drought assessment

Residencia para la especialización en la docencia hospitalaria: Reflexiones sobre cuestiones curriculares en el posgrado en Educación y Salud

Este artículo, trae a discusión la implementación de un curso de especialización para la formación de profesores para la atención escolar hospitalaria de alumnos gravemente enfermos. Tiene como contexto empírico el curso que se desarrolla en la modalidad de residencia realizado en una universidad pública en la ciudad de San Pablo, Brasil. Nuestro objetivo es identificar y analizar evidencias que surgen durante este proceso de implementación esperando contribuir con la reflexión de trayectorias curriculares posibles durante la formación del profesorado, relacionadas y articuladas con las prácticas y producción de saberes en la frontera de Educación y Salud. En síntesis, considerando la abundancia de desafíos cuando se propone un diálogo entre esferas y actores sociales tan diferentes como los profesionales de estas áreas, el papel del currículo debe pautarse por un carácter teórico, creativo y mediador, contribuyendo así para la autonomía del grup