Single-Board-Computer Clusters for Cloudlet Computing in Internet of Things

The number of connected sensors and devices is expected to increase to billions in the near future. However, centralised cloud-computing data centres present various challenges to meet the requirements inherent to Internet of Things (IoT) workloads, such as low latency, high throughput and bandwidth constraints. Edge computing is becoming the standard computing paradigm for latency-sensitive real-time IoT workloads, since it addresses the aforementioned limitations related to centralised cloud-computing models. Such a paradigm relies on bringing computation close to the source of data, which presents serious operational challenges for large-scale cloud-computing providers. In this work, we present an architecture composed of low-cost Single-Board-Computer clusters near to data sources, and centralised cloud-computing data centres. The proposed cost-efficient model may be employed as an alternative to fog computing to meet real-time IoT workload requirements while keeping scalability. We include an extensive empirical analysis to assess the suitability of single-board-computer clusters as cost-effective edge-computing micro data centres. Additionally, we compare the proposed architecture with traditional cloudlet and cloud architectures, and evaluate them through extensive simulation. We finally show that acquisition costs can be drastically reduced while keeping performance levels in data-intensive IoT use cases.Ministerio de Economía y Competitividad TIN2017-82113-C2-1-RMinisterio de Economía y Competitividad RTI2018-098062-A-I00European Union’s Horizon 2020 No. 754489Science Foundation Ireland grant 13/RC/209

Teaching Materials for Active Methodologies in University Education

In the present university educational model, teaching is less teacher-centered (instruction) and more student-centered (learning). In this context, it is essential to have adequate teaching materials to support the student, both in the learning process and in the evaluation stage of the subjects. Thus, the formative evaluation (it allows knowing the progress of the students, offering proposals for additional learning) becomes more important than merely summative evaluation (with the sole purpose of obtaining a grade). This article presents a teaching-learning proposal based on the experience accumulated by the authors over several years, in which different teaching innovations have been applied. These innovations were intended to facilitate learning, improve results, increase motivation, foster collaborative work and student involvement, among other objectives. It has been found that active methodologies improve learning results through student motivation and involvement. For their part, teaching materials play a fundamental role in guiding and orienting the students’ autonomous learning process and, at the same time, facilitating collaborative and participatory dynamics in the classroom

Benchmarking real-time vehicle data streaming models for a smart city

The information systems of smart cities offer project developers, institutions, industry and experts the possibility to handle massive incoming data from diverse information sources in order to produce new information services for citizens. Much of this information has to be processed as it arrives because a real-time response is often needed. Stream processing architectures solve this kind of problems, but sometimes it is not easy to benchmark the load capacity or the efficiency of a proposed architecture. This work presents a real case project in which an infrastructure was needed for gathering information from drivers in a big city, analyzing that information and sending real-time recommendations to improve driving efficiency and safety on roads. The challenge was to support the real-time recommendation service in a city with thousands of simultaneous drivers at the lowest possible cost. In addition, in order to estimate the ability of an infrastructure to handle load, a simulator that emulates the data produced by a given amount of simultaneous drivers was also developed. Experiments with the simulator show how recent stream processing platforms like Apache Kafka could replace custom-made streaming servers in a smart city to achieve a higher scalability and faster responses, together with cost reduction.This research is partially supported by the Spanish Ministry of Economy and Competitiveness and European Regional Development Fund (ERDF) through the “HERMES – SmartDriver” project (TIN2013-46801-C4-2-R), the “HERMES – Smart Citizen” project (TIN2013-46801-C4-1-R), and the “HERMES –Space&Time” project (TIN2013-46801-C4-3-R)

Impacto de la disfunción ventricular izquierda en el paciente intervenido de estenosis valvular aórtica moderada-grave

Objetivo: El objetivo de este estudio es analizar el efecto de la disfunción ventricular izquierda grave en la mortalidad de la cirugía de estenosis valvular aórtica aislada o combinada con cirugía coronaria en el Hospital Universitario Son Espases. Métodos: Se incluyeron 666 pacientes intervenidos desde noviembre del 2002 hasta diciembre del 2009 en nuestro centro. Los pacientes se clasificaron en dos grupos según su fracción de eyección (FE): ≤35% y >35%. Se excluyeron los pacientes con insuficiencia valvular aórtica severa asociada y/o los intervenidos de cualquier otra valvulopatía. El seguimiento se realizó hasta el 31 de diciembre del 2011. El análisis del efecto de la disfunción ventricular grave en la mortalidad a medio plazo se realizó mediante curvas de supervivencia y un análisis de regresión de Cox ajustado por factores de confusión. Resultados: El 42,49% (n = 283) eran mujeres. La mediana de edad fue de 71,42 años (62,82 – 80,02) y la del Euroscore logístico 5,82 (3,74 - 9,15). La mortalidad bruta hospitalaria observada fue del 2,1% (n = 14). La mediana del tiempo seguimiento fue de 4,6 años, muy similar en ambos grupos. El análisis de regresión de Cox mostró una asociación entre disfunción ventricular izquierda severa y mortalidad a medio plazo (HR 2,55, IC 95% 1,36 - 4,76). Conclusiones: La disfunción ventricular izquierda grave es un factor de riesgo independiente asociado con una mayor mortalidad a medio plazo en pacientes intervenidos de estenosis aórtica aislada o combinada con cirugía coronaria. Palabras clave: Estenosis de la válvula aórtica, mortalidad, disfunción ventricular, procedimientos quirúrgicos cardíacos, válvula aórticaObjective: The objective of this study was to analyze the impact of severe left ventricular dysfunction on mortality after aortic valve replacement with and without combined coronary artery bypass graft surgery in Son Espases University Hospital. Methods: We included 666 patients undergoing aortic valve replacement from November 2000 through December 2009. Patients were clasified in two groups according to the ejection fraction (EF): ≤35% and >35%. Patients with associated severe aortic valve insufficiency or undergoing another surgical valve procedure were excluded. Mortality following discharge was calculated from data on patient life status at December 31, 2011. The effect of severe left ventricular dysfunction on mid-term mortality was analyzed with Kaplan-Meyer survival estimates and a risk-adjusted Cox proportional regression model. Results: The proportion of female sex was 42,49% (n = 283). Median age was 71,42 years (62,82 – 80,02) and median logistic Euroscore was 5,82 (3,74 – 9,15). Observed in-hospital mortality was 2,1% (n = 14). Median time of follow-up was 4,6 years, very similar in both groups. Cox regression analysis showed an association between severe left ventricular dysfunction and mid-term mortality (HR 2,55, CI 95% 1,36 - 4,76). Conclusions: Severe left ventricular dysfunction is associated with a higher mid-term mortality in patients undergoing aortic valve replacement with and without combined coronary surgery, aortic valve. Keywords: Aortic Valve Stenosis, Mortality, Ventricular Dysfunction, Cardiac Surgical Procedures, aortic valv

Benchmarking a wide spectrum of metaheuristic techniques for the radio network design problem

The radio network design (RND) is an NP-hard optimization problem which consists of the maximization of the coverage of a given area while minimizing the base station deployment. Solving RND problems efficiently is relevant to many fields of application and has a direct impact in the engineering, telecommunication, scientific, and industrial areas. Numerous works can be found in the literature dealing with the RND problem, although they all suffer from the same shortfall: a noncomparable efficiency. Therefore, the aim of this paper is twofold: first, to offer a reliable RND comparison base reference in order to cover a wide algorithmic spectrum, and, second, to offer a comprehensible insight into accurate comparisons of efficiency, reliability, and swiftness of the different techniques applied to solve the RND problem. In order to achieve the first aim we propose a canonical RND problem formulation driven by two main directives: technology independence and a normalized comparison criterion. Following this, we have included an exhaustive behavior comparison between 14 different techniques. Finally, this paper indicates algorithmic trends and different patterns that can be observed through this analysis.Publicad

Infraestructuras para gestión de información de una SmartCity

JARCA 2015: Actas de las XVII Jornadas de ARCA: Sistemas Cualitativos y sus Aplicaciones en Diagnosis, Robótica, Inteligencia Ambiental y Ciudades Inteligentes = Proceedings of the XVII ARCA Days: Qualitative Systems and its Applications in Diagnose Robotics, Ambient Intelligence and Smart Cities, Vinaros (Valencia), 23 al 27 de Junio de 2015.En este trabajo se describe la infraestructura propuesta en el proyecto Nacional Hermes en el que se plantea un modelo de transición para llegar a crear ciudades inteligentes sin necesidad de grandes inversiones en infraestructuras.Este trabajo ha sido parcialmente financiado por el proyecto del Ministerio de Economía y Competitividad HERMES (TIN2013-46801-C4-1-r) y los proyectos de excelencia de la Junta de Andalucía Simon (P11-TIC-8052) y Context-Learning (P11-TIC-7124

On the physical properties of mixtures of nitrate salts and protic ionic liquids

We report a systematic study of the effect of salt concentration and its cation valence on several equilibrium and transport properties of mixtures of the model protic ionic liquid ethylammonium nitrate with monovalent (LiNO3), divalent (Mg(NO3)2 and Ca(NO3)2), and trivalent (Al(NO3)3) salts. These properties, determined by appropriate experimental techniques, include density, sound velocity, refractive index, surface tension, conductivity and viscosity. Single-particle dynamics and radial distribution functions were also analyzed by means of molecular dynamics simulations. The temperature dependence of the conductivity was studied in the Vogel-Fulcher-Tammann framework, and we obtained effective activation energies, fragility indexes, and Vogel temperatures. In addition, we performed a high-temperature Arrhenius analysis and we calculated the activation energies of both conductivity and viscosity. Finally, the exponents of the fractional Walden rule for the different mixtures were obtained and the ionicities and fragilities of the systems were analyzed, proving that all the mixtures are subionic and fragile. The distortion of the network of hydrogen bonds characteristic of protic ionic liquids and the formation of long-lived anionic aggregates composed of the cations of the added salt and the nitrate anions in their first solvation shell were found to have a deep impact on the analyzed properties. The role of the surface charge density of the salt cations on the structure and transport properties of the solutions is detailedly analyzed and related to solvation of salt species in the polar nanoregions of the ionic liquid (nanostructured solvation)The financial support of the Spanish Ministry of Economy and Competitiveness (Projects MAT2017-89239-C2-1-P and MAT2017-89239- C2-2-P) is gratefully acknowledged. Moreover, this work was funded by the Xunta de Galicia (ED431D 2017/06, ED431E 2018/08, GRC ED431C 2016/001 and GRC ED431C 2020/10). All these research projects were partially supported by FEDER. P. V. thanks the Spanish Ministry of Science, Innovation and Universities for his FPI grant (PRE2018-084212). T.M.-M. thanks the Spanish Ministry of Science, Innovation and Universities for her Juan de la Cierva grant (IJC2018-036774-I).J. J. Parajó thanks the funding support of I2C postdoctoral program of Xunta de Galicia. Y. A. thanks the funding support from postdoctoral Program of Xunta de Galicia (ED481B-2021-027)S

Cliocanarias III

Este número de Cliocanarias ofrece un conjunto de artículos de investigación y divulgación relativos a muy diversos temas y ámbitos territoriale

Diseño de una guía didáctica para la interpretación del paisaje a partir de recursos cartográficos online

El presente proyecto tiene por objetivo diseñar una guía didáctica para la interpretación del paisaje basada en cartografía digital online, adaptable a diferentes niveles académicos, cuyo fin será promover la educación en paisaje, de acuerdo con la necesidad que el Convenio Europeo del Paisaje (CEP) plantea acerca de contribuir a la formación de una sociedad que valore y demande paisajes de calidad, pues estos desempeñan un importante papel de interés general en los campos cultural, ecológico, medioambiental y social. El concepto de paisaje del que partimos es el acordado en el CEP y en las diferentes leyes del paisaje autonómicas españolas, entendiendo por paisaje no sólo aquellos espacios con altos valores naturales y/o estéticos, sino todo territorio tal y como lo percibe la sociedad. La guía supone el fruto de los resultados de numerosos trabajos llevados a cabo por el grupo en relación con la didáctica del paisaje. Entre ellos los PIMCD: 133/2011, 165/2013, 98/2014, 224/2015, 52/2016 y, principalmente del anterior 113/2017, en los que se han diseñado y aplicado recursos didácticos como comentario de imágenes, desarrollo de cartografía digital o diseño de itinerarios didácticos para la interpretación del paisaje en el ámbito de los Parques Nacionales españoles. Así, el proyecto se vertebra en dos líneas preferentes. Por un lado, acercar la diversidad de nuevas tecnologías y la información geográfica o geoinformación a través de una guía que compendia un variado elenco de recursos cartográficos digitales para el profesorado y alumnado, ofreciendo recursos que sirvan para el aprendizaje dentro y fuera del aula y, por otro, mejorar el conocimiento acerca de los valores naturales y culturales de los paisajes, fomentando una conciencia social que contribuya con su puesta en valor y mejora. La guía resultante podrá ser consultada en abierto y en el Atlas Digital Escolar por nuestros alumnos, tanto del Grado de Geografía y Ordenación del Territorio, los Grados de Maestro en Educación Infantil y Primaria así como de los másteres en Formación del Profesorado de ESO y Bachillerato, FP y Enseñanza de Idiomas, de Tecnologías de la Información y de Dinámicas Territoriales

Diseño de un modelo didáctico para la educación en paisaje utilizando Sigweb

A través del PIMCD 113, se ha diseñado e implementado un modelo didáctico para la educación en paisaje enfocado a alumnos del Grado de Maestro de Educación Primaria