Teaching high-performance service in a cluster computing course

[EN] Most courses on cluster computing in graduate and postgraduate studies are focused on parallel programming and high-performance/high-throughput computing. This is the typical usage of clusters in academia and research centres. However, nowadays, many companies are providing web, mail and, in general, Internet services using computer clusters. These services require a different ``cluster flavour'': high-performance service and high availability. Despite the fact that computer clusters for each environment demand a different configuration, most university cluster computing courses keep focusing only on high-performance computing, ignoring other possibilities. In this paper, we propose several teaching strategies for a course on cluster computing that could fill this gap. The content developed here would be taught as a part of the course. The subject shows several strategies about how to configure, test and evaluate a high-availability/load-balanced Internet server. A virtualization-based platform is used to build a cluster prototype, using Linux as its operating system. Evaluation of the course shows that students knowledge and skills on the subject are improved at the end of the course. On the other hand, regarding the teaching methodology, the results obtained in the yearly survey of the University confirm student satisfaction.This work was supported in part by the Spanish Ministerio de Economia y Competitividad (MINECO) and by FEDER funds under Grant TIN2015-66972-C5-1-R.López Rodríguez, PJ.; Baydal Cardona, ME. (2018). Teaching high-performance service in a cluster computing course. Journal of Parallel and Distributed Computing. 117:138-147. https://doi.org/10.1016/j.jpdc.2018.02.027S13814711

On a course on computer cluster configuration and administration

[EN] Computer clusters are today a cost-effective way of providing either high-performance and/or high-availability. The flexibility of their configuration aims to fit the needs of multiple environments, from small servers to SME and large Internet servers. For these reasons, their usage has expanded not only in academia but also in many companies. However, each environment needs a different ¿cluster flavour¿. High-performance and high-throughput computing are required in universities and research centres while high-performance service and high-availability are usually reserved to use in companies. Despite this fact, most university cluster computing courses continue to cover only high-performance computing, usually ignoring other possibilities. In this paper, a master-level course which attempts to fill this gap is discussed. It explores the different types of cluster computing as well as their functional basis, from a very practical point of view. As part of the teaching methodology, each student builds from scratch a computer cluster based on a virtualization tool. The entire process is designed to be scalable. The goal is to be able to apply it to an actual computer cluster with a larger number of nodes, such as those the students may subsequently encounter in their professional life.This work was supported in part by the Spanish Ministerio de Economia y Competitividad (MINECO) and by FEDER funds under Grant TIN2015-66972-C5-1-R.López Rodríguez, PJ.; Baydal Cardona, ME. (2017). On a course on computer cluster configuration and administration. Journal of Parallel and Distributed Computing. 105:127-137. https://doi.org/10.1016/j.jpdc.2017.01.009S12713710

A Survey on Optimization Techniques Applied to Magnetic Field Mitigation in Power Systems

With the continuous increase in the number and relevance of electric transmission lines and distribution networks, there is a higher exposure to the magnetic fields generated by them, leading to more cases of human electrosensitivity, which greatly necessitates the design and development of magnetic field mitigation procedures and, at the same time, the need to minimize both performance degradation and deterioration in the efficiency as well. During the last four decades, fruitful results have been reported about extremely low frequency magnetic field mitigation, giving a wide variety of solutions. This survey paper aims to give a comprehensive overview of cost-effective optimization techniques destined to magnetic field mitigation in power systems, with particular attention to the results reported in the last decade.Agencia Estatal de Investigación and Fondo Europeo de Desarrollo Regional (AEI/FEDER, UE) project ENE2017-89669-RUniversidad de Sevilla (VI PPIT-US) grant 2018/0000074

Evaluation of the power frequency magnetic field generated by three-core armored cables through 3D finite element simulations

The great expansion in offshore power plants is raising the concern regarding the cumulative effect of the electromagnetic field emissions caused by submarine power cables. In this sense, owners are required to predict these emissions during the permitting and consenting process of new power plants. This is a challenging task, especially in the case of HVAC three-core armored cables due to their complex geometry. Customarily, 2D approaches based on the finite element method (FEM) have been employed for evaluating the magnetic field emissions caused by these cables. However, inaccurate results are obtained since the phase conductors and armor twisting is omitted. This work develops, for the first time in the literature, an in-depth analysis of the magnetic field caused by this type of cable through an ultra-shortened 3D-FEM model, which is also faced to experimental measurements taken on an actual 132 kV, 800 mm2 three-core armored cable. Relevant conclusions are derived regarding the impact of the cable design on the magnetic field emissions, including material properties, as well as single and double-layer armors, presenting the proposed model not only as a valuable tool for predicting purposes, but also for optimizing cable design in terms of magnetic field emissions

Burnout, Resilience, and COVID-19 among Teachers: Predictive Capacity of an Artificial Neural Network

Emotional exhaustion, cynicism, and work inefficiency are three dimensions that define burnout syndrome among teachers. On another note, resilience can be understood as the ability to adapt to the environment and overcome adverse situations. In addition, COVID-19 has provided a threatening environment that has led to the implementation of resilience strategies to struggle with burnout and cope with the virus. The aim of this study was to analyze the relationship between resilience, burnout dimensions, and variables associated with COVID-19 through the design of an artificial neural network architecture. For this purpose, the Maslach Burnout InventoryGeneral Survey (MBI-GS), the Brief Resilience Coping Scale (BRCS), and a questionnaire on stress towards COVID-19 were administered to 419 teachers from secondary schools in southeastern Spain (292 females; 69.7%). The results showed that 30.8% suffered from burnout (high emotional exhaustion, high cynicism, and low professional efficacy) and that 38.7% had a high level of resilience, with an inverse relationship between both constructs. Likewise, we modelled an ANN able to predict burnout syndrome among 97.4% of teachers based on its dimensions, resilience, sociodemographic variables, and the stress generated by COVID-19. Our conclusions shed some light on the efficacy of relying on artificial intelligence in the educational field to predict the psychological situation of teachers and take early action

Evaluation of Reliefs’ Properties on Design of Thermoformed Packaging Using Fused Deposition Modelling Moulds

The increased consumption of food requiring thermoformed packaging implies that the packaging industry demands customized solutions in terms of shapes and sizes to make each packaging unique. In particular, food industry increasingly requires more transparent packaging, with greater clarity and a better presentation of the product they contain. However, in turn, the differentiation of packaging is sought through its geometry and quality, as well as the arrangement of food inside the packaging. In addition, these types of packaging usually include ribs in the walls to improve their physical properties. However, these ribs also affect the final aesthetics of the product. In accordance with this, this research study analyses the mechanical properties of different relief geometries that can affect not only their aesthetics but also their strength. For this purpose, tensile and compression tests were carried out using thermoformed PET sheets. The results provide comparative data on the reliefs studied and show that there are differences in the mechanical properties according to shape, size and disposition in the package

Influence of irrigation conditions in the germination of plasma treated Nasturtium seeds

Plasma treatments had emerged as a useful technique to improve seed germination. In this work we investigate the influence of different irrigation conditions and plasma treatments on the germination of nasturtium seeds. During plasma treatment, seeds experience a progressive weight loss as a function of treatment time that has been associated to water release, a process that is more pronounced after longer plasma treatment times. Seeds treated for short times (<30 s) are able to germinate more efficiently than untreated specimen under hydric stress (drought conditions), while plasma treatments for longer times (up to 300 s) impaired germination independently on irrigation conditions. Characterization analysis of plasma treated seeds by FTIR-ATR, SEM/EDX and XPS showed that plasma treatment affected the chemical state of pericarp while, simultaneously, induced a considerable increase in the seeds water uptake capacity. The decrease in germination efficiency found after plasma treatment for long times, or for short times under optimum irrigation conditions, has been attributed to that the excess of water accumulated in the pericarp hampers the diffusion up to the embryo of other agents like oxygen which are deemed essential for germination.España FEDER y MINECO MINECO (projects MAT2013-40852-R, MAT2016-79866-R, MINECOCSIC 201560E055)España, RECUPERA 2020 y Junta de Andalucía project P12-2265 M

Custom Design of Packaging through Advanced Technologies: A Case Study Applied to Apples

In the context of food packaging design, customization enhances the value of a product by meeting consumer needs. Personalization is also linked to adaptation, so the properties of the packaging can be improved from several points of view: functional, aesthetic, economic and ecological. Currently, functional and formal properties of packaging are not investigated in depth. However, the study of both properties is the basis for creating a new concept of personalized and sustainable product. In accordance with this approach, a conceptual design procedure of packaging with personalized and adapted geometries based on the digitization of fresh food is proposed in this work. This study is based on the application of advanced technologies for the design and development of food packaging, apples in this work, in order to improve the quality of the packaging. The results obtained show that it is possible to use advanced technologies in the early stages of product design in order to obtain competitive products adapted to new emerging needs

Sedimentology and stratigraphic architecture of Barremian synrift barrier island–estuarine depositional systems from blended field and drone-derived data

The Lower Cretaceous (Barremian) Camarillas Formation in the Galve Sub-basin of eastern Spain is an exceptionally muddy, synrift, aggradational then retrogradational paralic succession. Deposition within these arid, equatorial paralic systems was strongly controlled by crustal rifting of the Iberia plate linked to the geodynamic evolution of the Atlantic Ocean, the Bay of Biscay and the Tethys Ocean. Although synsedimentary extensional tectonics controlled thickness and facies distributions, the parasequence stacking patterns point to a superimposed high-order allogenic control on the paralic succession. Field data and drone imagery are combined to document changes in sedimentology and three-dimensional stratigraphic architecture of these deposits to interpret changes in depositional environments as this basin filled. Three evolutionary stages are identified: (i) tide-dominated estuary; (ii) mixed-energy estuary, with a well-developed wave-dominated barrier island system; and (iii) barrier island–tidal inlet suite. An exceptional record of back-barrier-island depositional interactions is preserved in this high-subsidence, extensional-basin setting, including deposition of washover fans, flood-tidal deltas and ebb-tidal deltas. Drone-derived imagery facilitates three-dimensional architectural characterization of these complex paralic deposits, including multi-episodic tidal inlets, and correlation of basin scale stratigraphic markers. Spatio-temporal interactions between climate change, sea-level variations and rift-related subsidence generated complex estuarine and barrier island geobodies. The general transgressive trend recorded in the Camarillas Formation correlates well with global eustatic sea-level rise during the Barremian

Gas phase selective hydrogenation of furfural to furfuryl alcohol and 2-methylfuran over Cu-CeO2 coprecipitated catalysts

Furfural is an important chemical derived from lignocellulosic biomass, in particular from C5 sugars like xylose, and it is considered as a platform molecule of great potential for the synthesis of a broad spectrum of chemicals. In this sense, furfuryl alcohol and 2-methylfuran are two important chemicals which can be produced through furfural hydrogenation, either in liquid or vapor phase, although the latter is preferred because it can be carried out at atmospheric pressure. Industrially, a copper chromite catalyst is used, although this catalyst can become very toxic due to the presence of chromium. Therefore, much attention is being paid to the development of chromium-free catalysts, more sustainable and environmentally friendly, as those based on Cu or Ni which are active and selective towards the formation of furfuryl alcohol and 2-methylfuran. Furfuryl alcohol is mainly used for the production of thermostatic resins, intermediate in the manufacture of lysine, vitamin C and dispersing agents. Meanwhile, 2-methyl furan is used in the synthesis of pesticides, or in the pharmaceutical and fragrance industries. The aim of this work is the synthesis of a series of copper based catalysts, which have been synthesized by coprecipitation of copper and cerium(IV) and subsequent thermal programmed reduction. This method allows increasing the dispersion of Cu particles, while the use of a support like CeO2 can modify the electronic density of the active phase, which can influence the catalytic activity and resistance to deactivation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Economy and Competitiveness Ministry (Project CTQ2012-38204-C03-02), Junta de Andalucía (Project: RNM-1565) and FEDER funds of the European Unio