3,394 research outputs found
Intrusion Detection System for Platooning Connected Autonomous Vehicles
The deployment of Connected Autonomous Vehicles (CAVs) in Vehicular Ad Hoc Networks (VANETs) requires secure wireless communication in order to ensure reliable connectivity and safety. However, this wireless communication is vulnerable to a variety of cyber atacks such as spoofing or jamming attacks. In this paper, we describe an Intrusion Detection System (IDS) based on Machine Learning (ML) techniques designed to detect both spoofing and jamming attacks in a CAV environment. The IDS would reduce the risk of traffic disruption and accident caused as a result of cyber-attacks. The detection engine of the presented IDS is based on the ML algorithms Random Forest (RF), k-Nearest Neighbour (k-NN) and One-Class Support Vector Machine (OCSVM), as well as data fusion techniques in a cross-layer approach. To the best of the authors’ knowledge, the proposed IDS is the first in literature that uses a cross-layer approach to detect both spoofing and jamming attacks against the communication of connected vehicles platooning. The evaluation results of the implemented IDS present a high accuracy of over 90% using training datasets containing both known and unknown attacks
Electrical properties of individual tin oxide nanowires contacted to platinum electrodes
A simple and useful experimental alternative to field-effect transistors for measuring electrical properties
free electron concentration nd, electrical mobility , and conductivity in individual nanowires has been
developed. A combined model involving thermionic emission and tunneling through interface states is proposed
to describe the electrical conduction through the platinum-nanowire contacts, fabricated by focused ion
beam techniques. Current-voltage I-V plots of single nanowires measured in both two- and four-probe
configurations revealed high contact resistances and rectifying characteristics. The observed electrical behavior
was modeled using an equivalent circuit constituted by a resistance placed between two back-to-back Schottky
barriers, arising from the metal-semiconductor-metal M-S-M junctions. Temperature-dependent I-V measurements
revealed effective Schottky barrier heights up to BE= 0.4 eV
Eficacia de la suplementación con β-hydroxy-β-methylbutyrate (HMB) en el deporte: actualización e implicación práctica
Introduction: although β-hydroxy-β-methylbutyrate
(HMB) is generally marketed as a supplement for increasing
muscle mass and strength, it is still not fully understood
how and in which particular sports and conditions
HMB can be more effective.
Aims: the primary purpose of this review is to update
and summarize the current knowledge about the usefulness
of HMB and to organize this information by different
sports with specific reference to sports with high
wear and tear phenomena as soccer, rugby or football.
Methods: a search was performed in PubMed database.
This review presents the results about HMB use in
sport.
Results: the articles identified in this review support
the notion that HMB could help to attenuate tissue catabolism
and initiate muscle anabolism particularly in untrained
individuals exposed to strenuous exercise or when
trained individual are exposed to periods of high physical
stress. HMB could therefore be applied in some specific
periods of athlete’s season where there are high-intensity
training periods, high density of competitions and little
recovery time between them, starting recovery phases
from an injury period and/or any other different situation
where performance or recovery could be affected by
a great catabolic environment.
Conclusion: this update contributes to clarify and define
possible mechanisms and/or effectiveness of HMB
supplementation related to endurance sports (i.e. cycling
and athletics), strength-power sports (i.e. resistance training,
football, rugby, soccer, judo, waterpolo and rowing)
and recreational activities.Introducción: aunque el β-hidroxi-β-metilbutirato
(HMB) se ha empleado generalmente como suplemento
para aumentar la masa muscular y la fuerza, es necesario
un mejor entendimiento de su función y averiguar en qué
deportes es más efectivo.
Objetivos: el objetivo principal de esta revisión es actualizar
y resumir el conocimiento existente en torno a la
utilización del HMB para clasificarla en función de cada
modalidad deportiva, con especial mención a aquellas
actividades con un alto grado de destrucción muscular,
como pueden ser el fútbol, el rugby o el fútbol americano.
Métodos: se utilizó la base de datos PubMed para la
búsqueda de artículos. Esta revisión presenta los resultados
sobre la utilización de HMB clasificados por deportes.
Resultados: la mayoría de los artículos seleccionados
sugieren que cuando una persona entrenada o no entrenada
se somete a un ejercicio intenso o diferente al habitual,
el HMB puede atenuar el catabolismo muscular
producido e iniciar los procesos anabólicos necesarios
para recuperar lo antes posible. De esta forma, el HMB
podría aplicarse en algunos momentos concretos de la
temporada deportiva en los que hubiera períodos con
entrenamientos de alta intensidad, o durante un periodo
con alta densidad competitiva y con poca recuperación
entre competiciones, o bien durante las primeras fases
de la readaptación física después de una lesión y/o durante
cualquier otra situación en la que el rendimiento o
la recuperación se pueden ver afectados por un entorno
altamente catabólico.
Conclusión: esta revisión pretende aclarar y definir
los posibles mecanismos por los que la suplementación
con HMB puede ser efectiva en deportes de resistencia
(ciclismo y carreras de fondo), en deportes de fuerza-potencia
(fútbol, yudo, waterpolo, remo, fútbol americano y
musculación) y en actividades deportivas recreacionales.This work was supported by the Andalusian Sports Medicine Centre (C.A.M.D.) through project no. EX-2005/07.
FBO is granted by the Ministry of Economy and
Competitiveness (RYC-2011-09011)
A Methodology to Analyze and Evaluate the Uncertainty Propagation due to Temperature and Frequency and Design Optimization for EMC Testing Instrumentation
This paper presents a study and proposes a new methodology to analyze, evaluate and reduce the overall uncertainty of instrumentations for EMC measurements. For the scope of this work, the front end of a commercial EMI receiver is chosen and variations due to tolerances, temperature and frequency response of the system are evaluated. This paper illustrates in detail how to treat each block composing the model by analyzing each discrete component, and how to evaluate their influence on the measurand. Since a model can have hundreds or even thousands of parameters, the probability distribution functions (PDFs) of some variable might be unknown. So, a method that allows to obtain in a fast and easy way the uncertainty of the measurement despite having so many variables, to then being able to evaluate the influence of each component on the measurand, is necessary for a correct design. In this way, it will be possible to indicate which discrete components have the most influence on the measurand and thus set the maximum tolerances allowed and being able to design a cost-effective solution. Furthermore, this works presents a methodology which can easily be extended and applied to estimate and compute the uncertainty for electromagnetic interferences, energy storage systems (ESS), energy production, electric machines, electric transports and power plants in genera
20 años conservando semillas en el Banco de Germoplasma de la Flora Silvestre de la Generalitat Valenciana
Han pasado más de dos décadas desde que se realizaron las primeras recolecciones de semillas de especies de flora rara, endémica y/o amenazada con fines conservacionistas por parte de la administración autonómica valenciana, cuya actuación técnica se desarrolla a través del Servicio de Vida Silvestre (SVS) de la Generalitat ValencianaLas actividades aquí indicadas han sido cofinanciadas por la Comisión Europea a través de programas LIFE, FEOGA, FEADER y FEDER en la Comunidad Valencian
Datació absoluta de ceràmica pretalaiòtica de l'illa de Menorca
La datació mitjançant termoluminiscència de ceràmiques prehistòriques de la naveta d'enterrament de tipus intermedi de Biniac-l'Argentina de l'illa de Menorca, proporciona edats que perrneten documentar el grup cultural pretalaiotic en dates que van del segle XXIV al XVI a.e. Aquests resultats complementen l'esquema cronològic de la prehistòria de Menorca en un període del qual no es disposava de cap tipus de dates absolutes. Les dates aportades perrneten suposar per a la naveta una major antiguitat de l'acceptada generalment. Així doncs, caldrà esperar noves dates absolutes que confirmin aquesta tendència a situar a grans trets el complex cultural pretalaiòtic en un moment que compren el III mil·leni i la primera meitat del II a.C. ria de Menorca, cultura pretalaiotica, datació absoluta, terrnoluminiscencia, ceramica.Therrnoluminescence dating of prehistoric pottery from the intermediate type burial naveta in Biniac-l' Argentina (Minorca island), provides ages that perrnit to place the retalaiothic cultural group between the XXIV and XVII centuries b.e. These results fill sorne gaps in the chronological scheme of Minorca prehistory during a period in which no absolute dates were available. The dates indicate that the naveta is older than generally accepted. Therefore, to confirrn that the pretalaiothic cultural complex existed in a period comprised between the III rnillennium and the first half of the II b.C, we should wait for new absolute dates
Improving degradation of emerging organic compounds by applying chaotic advection in Managed Aquifer Recharge in randomly heterogeneous porous media
Improving degradation rates of emerging organic compounds (EOCs) in groundwater is still a challenge. Although their degradation is not fully understood, it has been observed that some substances are preferably degraded under specific redox conditions. The coupling of Managed Aquifer Recharge with soil aquifer remediation treatment, by placing a reactive layer containing organic matter at the bottom of the infiltration pond, is a promising technology to improve the rate of degradation of EOCs. Its success is based on assuming that recharged water and groundwater get well mixed, which is not always true. It has been demonstrated that mixing can be enhanced by inducing chaotic advection through extraction-injection-engineering. In this work, we analyze how chaotic advection might enhance the spreading of redox conditions with the final aim of improving degradation of a mix of benzotriazoles: benzotriazole, 5-methyl-benzotriazole, and 5-chloro-benzotriazole. The degradation of the first two compounds was fastest under aerobic conditions whereas the third compound was best degraded under denitrification conditions. We developed a reactive transport model that describes how a recharged water rich in organic matter mixes with groundwater, how this organic matter is oxidized by different electron acceptors, and how the benzotriazoles are degraded attending for the redox state. The model was tested in different scenarios of recharge, both in homogenous and in heterogenous media. It was found that chaotic flow increases the spreading of the plume of recharged water. Consequently, different redox conditions coexist at a given time, facilitating the degradation of EOCs.Peer ReviewedPostprint (author's final draft
Tectonic evolution of Variscan Iberia: Gondwana–Laurussia
An integrated interpretation of the late Paleozoic structural and geochronological record of the Iberian Massif is
presented and discussed under the perspective of a Gondwana-Laurussia collision giving way to the Variscan
orogen. Compressional and extensional structures developed during the building of the Variscan orogenic crust
of Iberia are linked together into major tectonic events operating at lithosphere scale. A review of the
tectonometamorphic and magmatic evolution of the IberianMassif reveals backs and forths in the overall conver-
gence between Gondwana and Laurussia during theamalgamation of Pangea in late Paleozoic times. Stages dom-
inated by lithosphere compression are characterized by subduction, both oceanic and continental, development
of magmatic arcs, (over- and under-) thrusting of continental lithosphere, and folding. Variscan convergence re-
sulted in the eventual transference of a large allochthonous set of peri-Gondwanan terranes, the Iberian
Allochthon, onto the Gondwana mainland. The Iberian Allochthon bears the imprint of previous interaction be-
tween Gondwana and Laurussia, including their juxtaposition after the closure of the Rheic Ocean in Lower De-
vonian times. Stages governed by lithosphere extension are featured by the opening of two short-lived oceanic
basins that dissected previous Variscan orogenic crust, first in the Lower-Middle Devonian, following the closure
of the Rheic Ocean, and then in the early Carboniferous, following the emplacement of the peri-Gondwanan
allochthon. An additional, major intra-orogenic extensional event in the early-middle Carboniferous dismem-
bered the Iberian Allochthon into individual thrust stacks separated by extensional faults and domes. Lateral tec-
tonics played an important role through the Variscan orogenesis, especially during the creation of new tectonic
blocks separated by intracontinental strike-slip shear zones in the late stages of continental convergence
Optimal Reconfiguration of a Limited Parallel Robot for Forward Singularities Avoidance
[EN] The positioning of the anchoring points of a Parallel Kinematic Manipulator has an important impact on its later performance. This paper presents an optimization problem to deal with the reconfiguration of a Parallel Kinematic manipulator with four degrees of freedom and the corresponding algorithms to address such problem, with the subsequent test on an actual robot. The cost function minimizes the forces applied by the actuators along the trajectory and considers singular positions and the feasibility of the active generalized coordinates. Results are compared among different algorithms, including evolutionary, heuristics, multi-strategy and gradient-based optimizers.This work was supported by the Spanish Ministry of Education, Culture and Sports through the
Project for Research and Technological Development with Ref. DPI2017-84201-RLlopis-Albert, C.; Valero, F.; Mata, V.; Escarabajal, RJ.; Zamora-Ortiz, P.; Pulloquinga, JL. (2020). Optimal Reconfiguration of a Limited Parallel Robot for Forward Singularities Avoidance. Multidisciplinary Journal for Education, Social and Technological Sciences. 7(1):113-127. https://doi.org/10.4995/muse.2020.13352OJS11312771Arakelian, V., Briot, S., & Glazunov, V. (2008). Increase of singularity-free zones in the workspace of parallel manipulators using mechanisms of variable structure. Mechanism and Machine Theory, 43(9), 1129-1140. https://doi.org/10.1016/J.MECHMACHTHEORY.2007.09.005Araujo-Gómez, P., Díaz-Rodríguez, M., Mata, V., & González-Estrada, O. A. (2019). Kinematic analysis and dimensional optimization of a 2R2T parallel manipulator. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 41(10), 425. https://doi.org/10.1007/s40430-019-1934-1Araujo-Gómez, P., Mata, V., Díaz-Rodríguez, M., Valera, A., & Page, A. (2017). Design and kinematic analysis of a novel 3UPS/RPU parallel kinematic mechanism with 2T2R motion for knee diagnosis and rehabilitation tasks. Journal of Mechanisms and Robotics, 9(6), 061004. https://doi.org/10.1115/1.4037800Beiranvand, V., Hare, W., & Lucet, Y. (2017). Best practices for comparing optimization algorithms. Optimization and Engineering, 18(4), 815-848. https://doi.org/10.1007/s11081-017-9366-1Dash, A. K., Chen, I. M., Yeo, S. H., & Yang, G. (2005). Workspace generation and planning singularity-free path for parallel manipulators. Mechanism and Machine Theory, 40(7), 776-805. https://doi.org/10.1016/j.mechmachtheory.2005.01.001Gosselin, C., & Angeles, J. (1990). Singularity Analysis of Closed-Loop Kinematic Chains. IEEE Transactions on Robotics and Automation, 6(3), 281-290. https://doi.org/10.1109/70.56660Llopis-Albert, C., Rubio, F., & Valero, F. (2018). Optimization approaches for robot trajectory planning. Multidisciplinary Journal for Education, Social and Technological Sciences, 5(1), 1. https://doi.org/10.4995/muse.2018.9867Patel, Y. D., & George, P. M. (2012). Parallel Manipulators Applications-A Survey. Modern Mechanical Engineering, 02(03), 57-64. https://doi.org/10.4236/mme.2012.23008Rubio, F., Llopis-Albert, C., Valero, F., & Suñer, J. L. (2016). Industrial robot efficient trajectory generation without collision through the evolution of the optimal trajectory. Robotics and Autonomous Systems, 86, 106-112. https://doi.org/10.1016/j.robot.2016.09.008Rubio, F., Valero, F., & Llopis-Albert, C. (2019). A review of mobile robots: Concepts, methods, theoretical framework, and applications. International Journal of Advanced Robotic Systems, 16(2), 172988141983959. https://doi.org/10.1177/1729881419839596Tsai, L.-W. (1999). Robot Analysis and Design. John Wiley & Sons, Inc. New York, NY, USA ©1999.Valero, F., Rubio, F., & Llopis-Albert, C. (2019). Assessment of the Effect of Energy Consumption on Trajectory Improvement for a Car-like Robot. Robotica, 37(11), 1998-2009. https://doi.org/10.1017/S0263574719000407Vallés, M., Araujo-Gómez, P., Mata, V., Valera, A., Díaz-Rodríguez, M., Page, Á., & Farhat, N. M. (2018). Mechatronic design, experimental setup, and control architecture design of a novel 4 DoF parallel manipulator. Mechanics Based Design of Structures and Machines, 46(4), 425-439. https://doi.org/10.1080/15397734.2017.1355249Wehage, K. T., Wehage, R. A., & Ravani, B. (2015). Generalized coordinate partitioning for complex mechanisms based on kinematic substructuring. Mechanism and Machine Theory, 92, 464-483. https://doi.org/10.1016/j.mechmachtheory.2015.06.006www.esteco.com. (n.d.). Retrieved June 10, 2019, from https://www.esteco.com/Xianwen Kong, B., & Gosselin, C. M. (2002). Kinematics and singularity analysis of a novel type of 3-CRR 3-DOF translational parallel manipulator. International Journal of Robotics Research, 21(9), 791-798. https://doi.org/10.1177/02783649020210090501Yang, X. (2017). Optimization Algorithms Optimization and Metaheuristic Algorithms in Engineering. (March). https://doi.org/10.1007/978-3-642-20859-
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