170 research outputs found
Extraction and Use of Geometry Data to Obtain 3D Buildings on a Web Map
The Fifth International Conference on Advances in Computation, Communications and Services ACCSE 2020, 27/09/2020-01/10/2020, Lisboa, PortugalThis work shows a comparison between two different techniques to obtain 3D buildings on a web map. The first one is based on the XYZ Tiles server of OSM Buildings and the second one is based on the Overpass servers of the collaborative project OpenStreetMap. Several simulations have been carried out to analyze their performance. Benefits and limitations of both methods are discussed.Comunidad de MadridUniversidad de Alcal
On the use of Websockets to maintain temporal states in stateless applications
The Fifteenth International Conference on Internet and Web Applications and Services ICIW 2020, 27/09/2020-01/10/2020, Lisboa, PortugalThis paper studies the use of Websockets to maintain temporal states in stateless applications. Concretely, it is used in a web-based application that calculates the propagation loss in outdoor environments. The reasons why Websockets are used and their limitations are discussed. A comparison with other similar technologies is also included.Comunidad de MadridUniversidad de Alcal
Analysis on the lack of motivation and dropout in engineering students in Spain
The dropout rate of engineering students is a concerning problem at the present time in many countries, resulting in difficulties to follow the demand of professionals in certain technological sectors as well as an associated negative economic impact. This study identifies a number of factors affecting the motivation degree of current electrical and computer engineering students, as well as the main reasons behind the dropout. A survey was completed by 624 students belonging to 8 different Spanish universities, rating the factors that could influence them to abandon their studies and those affecting their motivation to continue studying. Non-parametric analyses were performed in order to test the association of motivation as well as self-reported likelihood of dropping out with several variables. According to the research results, 23 of the 40 analyzed factors are correlated with the degree of motivation and 14 factors are correlated with the self-reported probability of dropping out. About 46% of the students declared to have thought about dropping out at some point in the past. Difficulty, followed by bad academic performance and negative relationships with professors are the main reasons for dropping out given by the students. Lack of vocation and distance to their home address were less frequent reasons.Universidad de Alcal
Analysis of Mobile Commerce in the SMEs of the European Union
This paper examines the situation of e-commerce and m-commerce in SMEs in the European Union and analyses if their behaviour in this field is determined by a series of factors, such as the size of the company, the type of business, turnover, etc. which may also influence their needs of specific training for their employees. This study is based on an online survey responded by 674 SMEs from eight different countries in Europe, aimed at providing training assistance to SMEs to support their efforts towards m-commerce. The objective is the analysis of the skills and knowledge to be recommended to employees of SMEs for a better preparation to implement the companies\u27 strategy of m-commerce. Although analysis of results from survey has supported the initial goal of developing training courses for m-commerce which include different economic, legal and technical topics, it has mainly provided very relevant conclusions on the factors which impact the adoption of e-commerce and m-commerce by SMEs
On the use of ray tracing programmable frameworks for radio wave propagation prediction
International Conference on Wireless Networks and Mobile Communication (EUIWNMC), 26/08/2021-27/08/2021, Marrakesh, Marruecos.This work focuses on the use of ray tracing programmable frameworks, like Nvidia Optix, for radio wave
propagation prediction. Although these frameworks are oriented to graphics visualization, they can be tailored to calculate
specular reflections on walls and diffractions in edges of buildings. Once all the paths between the transmitter and the
receiver are obtained, Maxwell"s equations can be applied to compute the path loss or the received power.Comunidad de Madri
Docker security in web simulation tools: a layered approach
International Conference on Wireless Networks and Mobile Communication (EUIWNMC), 26/08/2021-27/08/2021, Marrakesh, Marruecos.In this work, container security issues and strengths are studied using Docker as the main implementation. First,
the container infrastructure is described and compared against the traditional approach of virtual machines. Secondly, the
Docker containers security is discussed by the different infrastructure layers that compose them and different solutions are
proposed to try to decrease the attack surface over this kind of applications.Universidad de Alcal
Implementación de una herramienta para el diseño y análisis de reflectarrays
This paper presents a new computer aided technique to automatically design reflectarray antennas. The characteristics of the reflecting elements are selected considering the spatial phase delay at each unit cell to achieve a progressive phase shift. The reported technique is able to generate the geometrical model of the reflectarray antenna taking into account some input parameters such as the unit cell type, the operating frequency, the focal length, the periodicity and the desired main beam radiating direction. The tool also computes and provides the phase curve of the unit cell. To evaluate the performance of the new method, a reflectarray has been designed. Excellent results in terms of gain and polarization purity have been achieved
ZnO nanoparticles coated with oleic acid as additives for a polyalphaolefin lubricant
In this work, ZnO nanoparticles (NPs) were successfully synthesized and coated with oleic acid (OA). The mean diameter of these NPs (ZnO-OA) was around 11.5 nm, their core was characterized by XRD and their coating by FTIR and Raman. Homogeneous dispersions at different concentrations (0.10, 0.25, 0.50, 0.75 and 1.00 wt%) of ZnO-OA in polyalphaolefin 40 (PAO40) oil were thermophysically and tribologically characterized. Both density and viscosity values increased with the concentration of NPs, reaching relative increments of 0.5% and 4.0%, respectively, for the 1 wt% nanodispersion. Tribological tests were performed at 353.15 K using an Anton Paar MCR 302 rheometer equipped with a tribological ball-on three-pins configuration testing module. Regarding the tribological behavior, the optimal concentration was 0.25 wt% of ZnO-OA (25% of reduction in the friction coefficient and 82% wear reduction in terms of cross sectional area, respect to those obtained with the neat base oil). The rolling mechanism owing to the spherical shape of the nanoadditives, transforming sliding friction into rolling friction, and the mending effect could explain the better tribological performance of nanolubricants with respect to that of neat PAO40. In addition, the presence of PAO40, ZnO-OA NPs and iron oxides was evidenced from confocal Raman microscopy on the worn surfaces obtained from tribological test with PAO40 + 0.25 wt% ZnO-OA dispersionFunding for this work has been provided by the Ministry of Science, Innovation and Universities of Spain and the European Regional Development Fund (ERDF, FEDER in Spanish) through the ENE2017-86425-C2-2-R project, and by the Xunta de Galicia through ED431C 2020/10S
Tribological Behavior of Nanolubricants Based on Coated Magnetic Nanoparticles and Trimethylolpropane Trioleate Base Oil
The main task of this work is to study the tribological performance of nanolubricants formed by trimethylolpropane trioleate (TMPTO) base oil with magnetic nanoparticles coated with oleic acid: Fe3O4 of two sizes 6.3 nm and 10 nm, and Nd alloy compound of 19 nm. Coated nanoparticles (NPs) were synthesized via chemical co-precipitation or thermal decomposition by adsorption with oleic acid in the same step. Three nanodispersions of TMPTO of 0.015 wt% of each NP were prepared, which were stable for at least 11 months. Two different types of tribological tests were carried out: pure sliding conditions and rolling conditions (5% slide to roll ratio). With the aim of analyzing the wear by means of the wear scar diameter (WSD), the wear track depth and the volume of the wear track produced after the first type of the tribological tests, a 3D optical profiler was used. The best tribological performance was found for the Nd alloy compound nanodispersion, with reductions of 29% and 67% in friction and WSD, respectively, in comparison with TMPTO. On the other hand, rolling conditions tests were utilized to study friction and film thickness of nanolubricants, determining that Fe3O4 (6.3 nm) nanolubricant reduces friction in comparison to TMPTOThis research was supported by the Spanish Ministry of Economy and Competitiveness and the ERDF programme through the ENE2017-86425-C2-2-R project. Moreover, this work was funded by the Xunta de Galicia (ED431E 2018/08, GRC ED431C 2017/22 and GRC ED431C 2016/001). These three funders also financed the acquisition of the 3D Optical Profile Sensofar S Neox (UNST15-DE-3156)S
High mammographic density in long-term night shift workers: DDM-Spain /Var-DDM
[EN] Background: Night-shift work (NSW) has been suggested as a possible cause of breast cancer, and its association with mammographic density (MD), one of the strongest risk factors for breast cancer, has been scarcely addressed. This study examined NSW and MD in Spanish women.
Methods: The study covered 2,752 women aged 45-68 years recruited in 2007-2008 in 7 population-based public breast cancer screening centers, which included 243 women who had performed NSW for at least one year. Occupational data and information on potential confounders were collected by personal interview. Two trained radiologist estimated the percentage of MD assisted by a validated semiautomatic computer tool (DM-scan). Multivariable mixed linear regression models with random screening center-specific intercepts were fitted using log-transformed percentage of MD as the dependent variable and adjusting by known confounding variables.
Results: Having ever worked in NSW was not associated with MD [e(beta):0.96; 95% confidence interval (CI), 0.86-1.06]. However, the adjusted geometric mean of the percentage of MD in women with NSW for more than 15 years was 25% higher than that of those without NSW history (MD>15 (years):20.7% vs. MDnever:16.5%; e(beta):1.25; 95% CI, 1.01-1.54). This association was mainly observed in postmenopausal participants (e(beta):1.28; 95% CI, 1.00-1.64). Among NSW-exposed women, those with <= 2 night-shifts per week had higher MD than those with 5 to 7 nightshifts per week (e(beta):1.42; 95% CI, 1.10-1.84).
Conclusions: Performing NSW was associated with higherMD only in women with more than 15 years of cumulated exposure. These findings warrant replication in futures studies. (C)2017 AACR.We would like to thank the participants in the DDM-Spain/Var-DDM-Spain study for their contribution to breast cancer research. Other members of DDM-Spain/Var-DDM: Gonzalo. López-Abente, Roberto Pastor-Barriuso, Pablo Fernández-Navarro, Anna Cabanes, Soledad Laso, Manuela Alcaraz, María Casals, Inmaculada Martínez, Juan Carlos Pérez Cortés, Joaquín Antón, Nieves Ascunce, Isabel González-Román, Ana Belén Fernández, Montserrat Corujo, Soledad Abad, and Jesús Vioque. A.M. Pedraza-Flechas FI14CIII/00013 PFIS; B. Perez-Gomez FIS PS09/0790; M. Pollán FIS PI060386, EPY1306/06 collaboration agreement between Astra-Zeneca and ISCIII, and FECMA 485 EPY 1170 10; R. LLobet Gent per Gent Fund (EDEMAC Project); All authors: European Regional Development Fund (FEDER). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.Pedraza-Flechas, AM.; Lope, V.; Sanchez-Contador, C.; Santamarina, C.; Pedraz-Pingarron, C.; Moreo, P.; Ederra, M.... (2017). High mammographic density in long-term night shift workers: DDM-Spain /Var-DDM. Cancer Epidemiology Biomarkers & Prevention. 26(6):905-913. https://doi.org/10.1158/1055-9965.EPI-16-0507S90591326
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