Biblioteca Universidad Nebrija mOpac 2.3

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Dealing with Degeneracies in Automated Theorem Proving in Geometry [Recurso electrónico] / Zoltán Kovács, Tomas Recio, Luis F. Tabera, M. Pilar Vélez.

Autores: Kovács, Zoltán. ; Recio, Tomás. ; Tabera, Luis Felipe. ; Vélez Melón, M. Pilar.

a b 210923s2021uuuuxxx||0po 0 ||eng d 123442 eng 2021 RUNNE eng Dealing with Degeneracies in Automated Theorem Proving in Geometry [Recurso electrónico] / Zoltán Kovács, Tomas Recio, Luis F. Tabera, M. Pilar Vélez. Dominio público. application/pdftext/html Abstract: We report, through different examples, the current development in GeoGebra, a widespread Dynamic Geometry software, of geometric automated reasoning tools by means of computational algebraic geometry algorithms. Then we introduce and analyze the case of the degeneracy conditions that so often arise in the automated deduction in geometry context, proposing two different ways for dealing with them. One is working with the saturation of the hypotheses ideal with respect to the ring of geometrically independent variables, as a way to globally handle the statement over all non-degenerate components. The second is considering the reformulation of the given hypotheses ideal—considering the independent variables as invertible parameters—and developing and exploiting the specific properties of this zero-dimensional case to analyze individually the truth of the statement over the different non-degenerate components. info:eu-repo/semantics/openAccess. Sitio web de la revista (Consulta: 23-09-2021) Automated theorem proving in geometry Automated deduction in geometry Automated reasoning in geometry Dynamic Geometry GeoGebra Computational algebraic geometry Kovács, Zoltán. Recio, Tomás. Tabera, Luis Felipe. Vélez Melón, M. Pilar. Mathematics. -- 2021, v. 9, n. 16, 1964. 2227-7390 Mathematics. -- 2021, v. 9, n. 16, 1964. 2227-7390 https://doi.org/10.3390/math9161964 acceso al documento a través del sitio web de la revista

Anti-yaw damping monitoring of railway secondary suspension through a nonlinear constrained approach integrated with a randomly variable wheel-rail interaction [Recurso electrónico] / Ingo Kaiser, Salvatore Strano, Mario Terzo, Ciro Tordela.

Autores: Kaiser, Ingo. ; Strano, Salvatore. ; Terzo, Mario. ; Tordela, Ciro.

a b 210609s2021uuuuxxx|||||r z0 |eng d 121315 eng 2021 eng Anti-yaw damping monitoring of railway secondary suspension through a nonlinear constrained approach integrated with a randomly variable wheel-rail interaction [Recurso electrónico] / Ingo Kaiser, Salvatore Strano, Mario Terzo, Ciro Tordela. Documento no disponible en el fondo. Abstract: The real-time monitoring of railway vehicles is becoming a key factor for safety and the optimization of the maintenance costs. In this context, the secondary anti-yaw suspension system represents a key element, subjected to degradation phenomenon. This paper presents a model-based real time monitoring technique of the anti-yaw damping. The approach is based on a constrained nonlinear estimation procedure that employs a railway vehicle modelling characterized by the presence of a random walk model for the wheel-rail interaction. The technique allows to employ a model-based approach, with advantages in terms of robustness respect to the interaction parameters, a priori no knowledge of the track irregularities and constraints applied to the estimated states. Referencia y resumen en línea a través de la web de la revista (Consulta: 09-06-2021) Railway vehicle Anti-yaw damping Model-based estimator Monitoring Constrained estimation Track irregularities Condition-based maintenance Kaiser, Ingo. Strano, Salvatore. Terzo, Mario. Tordela, Ciro. Mechanical Systems and Signal Processing. -- 2021, v. 146, n. 1 (January), 107040. 0888-3270 2021, v. 146, n. 1 (January), 107040. 0888-3270 https://doi.org/10.1016/j.ymssp.2020.107040 acceso al documento (referencia y resumen)

Badea Romero, Francisco. Detailed Study on the Behavior of Improved Beam T-Junctions Modeling for the Characterization of Tubular Structures [Recurso electrónico]: Based on Artificial Neural Networks Trained with Finite Element Models / Francisco Badea, Jesus Angel Perez, Jose Luis Olazagoitia.

Autores: Pérez, Jesús Ángel. ; Olazagoitia Rodríguez, José Luis.

a b 210730s2021 xxx||0p 0 ||eng d 123022 eng 2021 RUNNE eng Badea Romero, Francisco. Detailed Study on the Behavior of Improved Beam T-Junctions Modeling for the Characterization of Tubular Structures [Recurso electrónico]: Based on Artificial Neural Networks Trained with Finite Element Models /Francisco Badea, Jesus Angel Perez, Jose Luis Olazagoitia. Dominio público. application/pdf Abstract: The actual behavior of welded T-junctions in tubular structures depends strongly on the topology of the junction at the joint level. In finite element analysis, beam-type elements are usually employed due to their simplicity and low computational cost, even though they cannot reproduce the joints topologies and characteristics. To adjust their behavior to a more realistic situation, elastic elements can be introduced at the joint level, whose characteristics must be determined through costly validations. This paper studies the optimization and implementation of the validation data, through the creation of an optimal surrogate model based on neural networks, leading to a model that predicts the stiffness of elastic elements, introduced at the joint level based on available data. The paper focuses on how the neural network should be chosen, when training data is very limited and, more importantly, which of the available data should be used for training and which for verification. The methodology used is based on a Monte Carlo analysis that allows an exhaustive study of both the network parameters and the distribution and choice of the limited data in the training set to optimize its performance. The results obtained indicate that the use of neural networks without a careful methodology in this type of problems could lead to inaccurate results. It is also shown that a conscientious choice of training data, among the data available in the problem of choice of elastic parameters for T-junctions in finite elements, is fundamental to achieve functional surrogate models. info:eu-repo/semantics/openAccess. Sitio web de la revista (Consulta: 30-07-2021) T-junctions Neural networks Finite elements analysis Surrogate Beam improvements Beam T-junctions models Artificial neural networks (ANN) limited training data Pérez, Jesús Ángel. Olazagoitia Rodríguez, José Luis. Mathematics. -- 2021, v. 9, n. 9, 943. 2227-7390 2021, v. 9, n. 9, 943. 2227-7390 https://doi.org/10.3390/math9090943 acceso al documento a través del sitio web de la revista

Boosting the Tunable Microwave Scattering Signature of Sensing Array Platforms Consisting of Amorphous Ferromagnetic Fe2.25Co72.75Si10B15 Microwires and Its Amplification by Intercalating Cu Microwires [Recurso electrónico] / Diego Archilla, Jesús López-Sánchez, Antonio Hernando, Elena Navarro, Pilar Marín.

Autores: Archilla Sanz, Diego. ; López Sánchez, Jesús. ; Hernando Grande, Antonio. ; Navarro Palma, Elena. ; Marín Palacios, María Pilar.

a b 210622s2020uuuuxxx||0po 0 ||eng d 121491 eng 2020 RUNNE eng Boosting the Tunable Microwave Scattering Signature of Sensing Array Platforms Consisting of Amorphous Ferromagnetic Fe2.25Co72.75Si10B15 Microwires and Its Amplification by Intercalating Cu Microwires [Recurso electrónico] / Diego Archilla, Jesús López-Sánchez, Antonio Hernando, Elena Navarro, Pilar Marín. Dominio público. application/pdf Abstract: The following work addresses new configurations of sensing array platforms that are composed of Co-based amorphous ferromagnetic microwires (MWs) to obtain an enhanced modulation of the microwave scattering effects through the application of low strength DC or AC magnetic fields. An amorphous MW is an ultrasoft ferromagnetic material (coercivity ~0.2 Oe) with a circumferential magnetic anisotropy that provides a high surface sensitivity when it is subjected to an external magnetic field. Firstly, microwave scattering experiments are performed as a function of the length and number of MWs placed parallel to each other forming an array. Subsequently, three array configurations are designed, achieving high S21 scattering coefficients up to about −50 dB. The influence of DC and AC magnetic fields on S21 has been analyzed in frequency and time domains representation, respectively. In addition, the MWs sensing array has been overlapped by polymeric surfaces and the variations of their micrometric thicknesses also cause strong changes in the S21 amplitude with displacements in the frequency that are associated to the maximum scattering behavior. Finally, a new concept for amplifying microwave scattering is provided by intercalating Cu MWs into the linear Co-based arrays. The designed mixed system that is composed by Co-based and Cu MWs exhibits a higher S21 coefficient when compared to a single Co-based MW system because of higher electrical conductivity of Cu. However, the ability to modulate the resulting electromagnetic scattering is conferred by the giant magneto-impedance (GMI) effects coming from properties of the ultrasoft amorphous MWs. The mixed array platform covers a wide range of sensor applications, demonstrating the feasibility of tuning the S21 amplitude over a wide scattering range by applying AC or DC magnetic fields and tuning the resonant frequency position according to the polymeric slab thickness. info:eu-repo/semantics/openAccess. Sitio web de la revista (Consulta: 22-06-2021) Soft magnetic materials Amorphous magnetic materials Magnetic microwires Microwave scattering Sensing array platforms Archilla Sanz, Diego. López Sánchez, Jesús. Hernando Grande, Antonio. Navarro Palma, Elena. Marín Palacios, María Pilar. Nanomaterials. -- 2021, v. 11, n. 4, 920. 2079-4991 Nanomaterials. -- 2021, v. 11, n. 4, 920. 2079-4991 https://doi.org/10.3390/nano11040920 acceso al documento a través del sitio web de la revista

Can a Semi-Active Energy Harvesting Shock Absorber Mimic a Given Vehicle Passive Suspension? [Recurso electrónico] / Jorge A. Reyes-Avendaño, Ciro Moreno-Ramírez, Carlos Gijón-Rivera, Hugo G. Gonzalez-Hernandez, José Luis Olazagoitia.

Autores: Reyes-Avendaño, Jorge A. ; Moreno Ramírez, Ciro. ; Gijón-Rivera, Carlos R. ; González-Hernández, Hugo G. ; Olazagoitia Rodríguez, José Luis.

a b 210923s2021uuuuxxx||0po 0 ||eng d 123448 eng 2021 RUNNE eng Can a Semi-Active Energy Harvesting Shock Absorber Mimic a Given Vehicle Passive Suspension? [Recurso electrónico] / Jorge A. Reyes-Avendaño, Ciro Moreno-Ramírez, Carlos Gijón-Rivera, Hugo G. Gonzalez-Hernandez, José Luis Olazagoitia. Dominio público. application/pdf Abstract: Energy harvesting shock absorbers (EHSA) have made great progress in recent years, although there are still no commercial solutions for this technology. This paper addresses the question of whether, and under what conditions, an EHSA can completely replace a conventional one. In this way, any conventional suspension could be replicated at will, while recovering part of the wasted energy. This paper focuses on mimicking the original passive damper behavior by continuously varying the electrical parameters of the regenerative damper. For this study, a typical ball-screw EHSA is chosen, and its equivalent suspension parameters are tried to be matched to the initial damper. The methodology proposes several electrical control circuits that optimize the dynamic behavior of the regenerative damper from the continuous variation of a load resistance. The results show that, given a target damper curve, the regenerative damper can adequately replicate it when there is a minimum velocity in the damper. However, when the damper velocity is close to zero, the only way to compensate for inertia is through the introduction of external energy to the system. info:eu-repo/semantics/openAccess. Sitio web de la revista (Consulta: 23-09-2021) Energy harvesting shock absorber Regenerative damper Semi-active suspension Reyes-Avendaño, Jorge A. Moreno Ramírez, Ciro. Gijón-Rivera, Carlos R. González-Hernández, Hugo G. Olazagoitia Rodríguez, José Luis. Sensors. -- 2021, v. 21, n. 13, 4378. 1424-8220 Sensors. -- 2021, v. 21, n. 13, 4378. 1424-8220 https://doi.org/10.3390/s21134378 acceso al documento a través del sitio web de la revista

La economía de la atención [Texto impreso] / Filippo Menczer, y Thomas Hills.

a b 210224s2021 esp|||p|r 0 |spa d 119098 spa 2021 La economía de la atención [Texto impreso] / Filippo Menczer, y Thomas Hills. Este artículo se encuentra disponible en su edición impresa. Los datos para su localización están accesibles a través del enlace al título de la publicación. Referencias bibliográficas: p. 45. La proliferación de la información reduce su calidad, y las redes sociales amplifican nuestros sesgos cognitivos de un modo nocivo. Eso nos hace vulnerables a la polarización y la manipulación. Para protegernos contra los engaños y restablecer la salud del ecosistema informativo, resulta esencial comprender esas vulnerabilidades cognitivas y cómo las explotan los algoritmos y bots. Las herramientas informáticas pueden ayudarnos a detectar cuentas falsas o a visualizar la propagación de bulos, pero para poner freno a la desinformación harán falta cambios institucionales. Investigación y ciencia. -- 2021 (Febrero), n. 533, p. [38]-45 Investigación y ciencia. -- 2021 (Febrero), n. 533, p. [38]-45

Educación en redes sociales [Texto impreso] : Instagram = Education in social : Instagram / Carlos Casado, Ginés Ciudad-Real.

a b 210215s2021 esp|||| r 0 |0spa d 118989 spa 2021 Educación en redes sociales [Texto impreso] : Instagram = Education in social : Instagram / Carlos Casado, Ginés Ciudad-Real. Este artículo se encuentra disponible en su edición impresa y electrónica. Los datos para su localización y/o acceso electrónico están accesibles a través del enlace al título de la publicación.Sección Tema del mes: El paradigma del coaching educativo = The paradigm of educational coaching. Que las redes sociales son un fenómeno que alcanza a todas las realidades es un hecho más que asumido. En enero de 2020, según un estudio publicado por la plataforma Hootsuite, solo Twitter, Facebook e Instagram acumulaban más de 3.800 millones de usuarios activos y almacenaban un gran repositorio de información de todos los ámbitos culturales y sociales.El ámbito educativo no escapa a este entorno digital en el que se crean, promocionan y, sobre todo, se comparten ideas, iniciativas y recursos entre una comunidad cada vez más acostumbrada a servirse de las redes sociales para la comunicación y el desempeño de la actividad docente. En este artículo hemos querido seleccionar algunas de las cuentas educativas de Instagram en las que encontrar recursos de ayuda para nuestras aulas.Abstract: It is an assumed fact that social networks are a phenomenon that reaches all kinds of realities. In January 2020, according to a study published by Hootsuite platform, only Twitter, Facebook and Instagram accumulated over 3,800 million active users, storing a big information repository of all cultural and social fields.The educational field does not fall outside this digital environment in which ideas, initiatives and resources are created, promoted and, above all, shared among a community more and more accustomed to making use of social networks for communication and development of teaching.In this article, we have wanted to select some of the Instagram educational accounts in which we can find helpful resources for our classrooms. Redes Sociales Instagram Recursos interactivos Comunidad Digital Social Networks Instagram Interactive resources Digital community Cuadernos de pedagogía. -- 2021 (Enero), n. 516, p. 129-134 Cuadernos de pedagogía. -- 2021 (Enero), n. 516, p. 129-134

Errores y sensacionalismo en la divulgación científica [Texto impreso] / Tomás Ortín, Ángel Uranga.

a b 210407s2021 esp|||p|r 0 |spa d 120576 spa 2021 Errores y sensacionalismo en la divulgación científica [Texto impreso] / Tomás Ortín, Ángel Uranga. Este artículo se encuentra disponible en su edición impresa. Los datos para su localización están accesibles a través del enlace al título de la publicación. Referencias bibliográficas: p. 41. La divulgación de la ciencia vive un momento dorado gracias al auge de los medios digitales y las redes sociales. Sin embargo, esa facilidad para dar y recibir información ha exacerbado algunos problemas que afectan a la calidad de la comunicación. Algunos de ellos son propios del periodismo tradicional, como la precipitación informativa o la mitomanía. Otros se deben a un mal uso de las herramientas propias de la divulgación científica, como las analogías y las simplificaciones. Ello no solo implica una mala comprensión de la ciencia por parte del público, sino que erosiona los estándares de lo que se considera riguroso y abona el terreno para los bulos y la desinformación. Varios ejemplos tomados de la física ilustran la situación. Investigación y ciencia. -- 2021 (Abril), n. 535, p. [34]-41 Investigación y ciencia. -- 2021 (Abril), n. 535, p. [34]-41

Escritores robóticos [Texto impreso] / Matthew Hutson.

a b 210724s2021 esp|||p|r 0 |spa d 121919 spa 2021 Escritores robóticos [Texto impreso] / Matthew Hutson. Este artículo se encuentra disponible en su edición impresa. Los datos para su localización están accesibles a través del enlace al título de la publicación. Referencias bibliográficas: p. 73. Los grandes modelos de lenguaje, entre los que destaca GPT-3, son programas de inteligencia artificial capaces de generar flujos de texto coherente a partir de una instrucción. Esos sistemas pueden realizar tareas para las que no han recibido entrenamiento específico tan bien como las personas, pero aún presentan sesgos y producen respuestas peligrosas o sin sentido. El problema fundamental es que los modelos carecen de sentido común y, aunque se están estudiando vías para que lo adquieran, quizá no lo logren mientras se limiten al ámbito del lenguaje. Investigación y ciencia. -- 2021 (Julio), n. 538, p. 68-73 Investigación y ciencia. -- 2021 (Julio), n. 538, p. 68-73

High-accuracy compliance correction for nonlinear mechanical testing [Recurso electrónico] : Improving Small Punch Test characterization / David Sánchez-Ávila, Alberto Orozco-Caballero, Elkin Martínez, Luis Portolés, Rafael Barea, Fernando Carreño.

Autores: Sánchez Ávila, David.

a b 210730s2021uuuuxxx|||||r z0 |eng d 123021 eng 2021 eng High-accuracy compliance correction for nonlinear mechanical testing [Recurso electrónico] : Improving Small Punch Test characterization /David Sánchez-Ávila, Alberto Orozco-Caballero, Elkin Martínez, Luis Portolés, Rafael Barea, Fernando Carreño. Documento no disponible en el fondo. Abstract: Small punch test, SPT, of metallic materials is a very convenient mechanical test since it requires a small volume of material. However, SPT data from different laboratories suffer from large scatter, mainly due to the different experimental set-ups, especially when displacement is measured without an LVDT. Such uncertainty is attributed predominantly to the large effect of elastic displacement associated to the low stiffness of the device set-up, which has not been taken properly into account so far. Additionally, we show that large stiffness variations during SPT are taking place. Thus, in this study, we present a methodology for performing the elastic correction in SPT load vs. displacement curves through a load-unload cycles test, allowing the attainment of the elastic displacement and associated stiffness for each unload step as a function of increasing SPT displacement. The proposed methodology provides SPT load vs. plastic displacement curves, which offer more accurate mechanical data and more reliable comparisons among different laboratories and materials, independently on the employed SPT set-up. Referencia y resumen en línea a través de la web de la revista (Consulta: 30-07-2021) 316L stainless steel SPT (Small Punch Test) FEM (Finite Element Modelling) SLM (Selective Laser Melting) Plastic deformation Sánchez Ávila, David. Nuclear Materials and Energy. -- 2021. v. 26 (March), 100914.2352-1791 2021. v. 26 (March), 100914. 2352-1791 https://doi.org/10.1016/j.nme.2021.100914 acceso al documento (referencia y resumen)

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