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Nomenclatura Unesco > (22) Física > (2203) Electrónica
(2203.01) Circuitos (2203.02) Elementos de circuitos
(2203.03) Válvulas electrónicas (2203.04) Microscopía electrónica
(2203.05) Estados electrónicos (2203.06) Transporte de electrones
(2203.07) Circuitos integrados (2203.08) Fotoelectricidad
(2203.09) Piezoelectricidad (2203.99) Otras (especificar)

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(3307) Tecnología electrónica

Mostrando recursos 1 - 20 de 249,401

1. Spain's Basques attack separatist violence with arts, investment / by Anne Swardson. - Swardson, Anne.
Documento electrónico extraido de Internet

2. 9-Fold Fresnel Köhler concentrator for increased uniform irradiance on high concentrations - Mendes Lopes, Joao; Benitez Gimenez, Pablo; Zamora Herranz, Pablo; Miñano Dominguez, Juan Carlos
Non-uniform irradiance patterns created by Concentrated Photovoltaics (CPV) concentrators over Multi-Junction Cells (MJC) can originate significant power losses, especially when there are different spectral irradiance distributions over the different MJC junctions. This fact has an increased importance considering the recent advances in 4 and 5 junction cells. The spectral irradiance distributions are especially affected with thermal effects on Silicone-on-Glass (SoG) CPV systems. This work presents a new CPV optical design, the 9-fold Fresnel Köhler concentrator, prepared to overcome these effects at high concentrations while maintaining a large acceptance angle, paving the way for a future generation of high efficiency CPV...

3. Numerical prediction of residual stresses fields induced in thin Al2024-T351 sheets by laser shock processing - Correa Guinea, Carlos; Morales Furió, Miguel; Porro González, Juan Antonio; Diaz Muñoz, Marcos; Ruiz de Lara de Luis, Leonardo; Peral Jiménez, David; Ocaña Moreno, Jose Luis
Outline: • Introduction • Numerical model SHOCKLAS© • Single LSP pulses • Overlapped LSP pulses • Discussion and Outlook

4. A novel FPGA-based evolvable hardware system based on multiple processing arrays - Gallego Galán, Ángel; Mora de Sambricio, Javier; Otero Marnotes, Andrés; Salvador Perea, Rubén; Torre Arnanz, Eduardo de la; Riesgo Alcaide, Teresa
In this paper, an architecture based on a scalable and flexible set of Evolvable Processing arrays is presented. FPGA-native Dynamic Partial Reconfiguration (DPR) is used for evolution, which is done intrinsically, letting the system to adapt autonomously to variable run-time conditions, including the presence of transient and permanent faults. The architecture supports different modes of operation, namely: independent, parallel, cascaded or bypass mode. These modes of operation can be used during evolution time or during normal operation. The evolvability of the architecture is combined with fault-tolerance techniques, to enhance the platform with self-healing features, making it suitable for applications which...

5. Application and modeling of GaN FET in 1MHz large signal bandwidth power supply for radio frequency power amplifier - Cucak, Dejana; Vasic, Miroslav; García Suárez, Oscar; Oliver Ramírez, Jesús Angel; Alou Cervera, Pedro; Cobos Márquez, José Antonio; Tadjer, Marko Jak; Calle Gómez, Fernando; Benkhelifa, F.; Reiner, R.; Waltereit, P.; Müller, S.
In this paper, implementation and testing of non- commercial GaN HEMT in a simple buck converter for envelope amplifier in ET and EER transmission techn iques has been done. Comparing to the prototypes with commercially available EPC1014 and 1015 GaN HEMTs, experimentally demonstrated power supply provided better thermal management and increased the switching frequency up to 25MHz. 64QAM signal with 1MHz of large signal bandw idth and 10.5dB of Peak to Average Power Ratio was gener ated, using the switching frequency of 20MHz. The obtaine defficiency was 38% including the driving circuit an d the total losses breakdown showed that switching power losses in the HEMT are the...

6. 9-fold Fresnel-Köhler concentrator for increased uniform irradiance on high concentrations - Mendes Lopes, Joao; Benitez Gimenez, Pablo; Zamora Herranz, Pablo; Miñano Dominguez, Juan Carlos
Non-uniform irradiance patterns created by Concentrated Photovoltaics (CPV) concentrators over Multi-Junction Cells (MJC) can originate significant power losses, especially when there are different spectral irradiance distributions over the different MJC junctions. This fact has an increased importance considering the recent advances in 4 and 5 junction cells. The spectral irradiance distributions are especially affected with thermal effects on Silicone-on-Glass (SoG) CPV systems. This work presents a new CPV optical design, the 9-fold Fresnel Köhler concentrator, prepared to overcome these effects at high concentrations while maintaining a large acceptance angle, paving the way for a future generation of high efficiency CPV...

7. Televisión, pantallas y convergencia digital [Recurso electrónico] : el consumo, clave de bóveda de la industria audiovisual / Ricardo Vaca Berdayes. - Vaca Berdayes, Ricardo.
En portada : [Lección en la] festividad de San Isidoro de Sevilla y de San Francisco de Sales, abril de 2015, Facultad de Humanidades y Ciencias de la Comunicación, Universidad CEU San Pablo, [43 pp]

8. Proyecto VEM [Recurso electrónico] : arquitecturas para un más vivir / Juan Manuel Ros García. - Ros García, Juan Manuel.
[Lección magistral en la] festividad de San José, marzo 2015, Escuela Politécnica Superior, Universidad CEU San Pablo; [44 pp]

9. Ganymede's interaction with the jovian plasma from hybrid simulation - Leclercq, Ludivine; Modolo, Ronan; Hess, Sebastien; Leblanc, François
Ganymede is a unique object: it is the biggest moon of our solar system, and the only satellite which has its own intrinsic magnetic field leading to the formation of a small magnetosphere. The magnetosphere of Ganymede being embedded in the Jovian magnetosphere, the environment of the Galilean moon presents the only known case of interaction between two magnetospheres (Kivelson et al. 1996). This peculiar interaction has been investigated by means of a 3D parallel multi-species hybrid model based on a CAM-CL algorithm (Mathews et al. 1994). This generic model has been largely used for other magnetized or unmagnetized bodies...

10. Cognitive impairment in first-episode mania: a systematic review of the evidence in the acute and remission phases of the illness - Daglas, Rothanthi; Yücel, Murat; Cotton, Sue; Allott, Kelly; Hetrick, Sarah; Berk, Michael
There is evidence of cognitive impairment that persists in the remission phase of bipolar disorder; however, the extent of the deficits that occur from the first onset of the disorder remains unclear. This is the first systematic review on cognitive functioning in the early stages of bipolar I disorder. The aim of the study was to identify the patterns and degree of cognitive impairment that exists from first-episode mania. Three electronic databases (MEDLINE, PsycINFO and PubMed) were systematically searched for studies published from January 1980 to June 2014. Eligible studies were separated into two groups: acute and remission. The Newcastle-Ottawa...

11. A holistic approach to ZigBee performance enhancement for home automation networks - Betzler, August; Gómez Montenegro, Carlos; Seyfettin Demirkol, Ilker; Paradells Aspas, Josep
Wireless home automation networks are gaining importance for smart homes. In this ambit, ZigBee networks play an important role. The ZigBee specification defines a default set of protocol stack parameters and mechanisms that is further refined by the ZigBee Home Automation application profile. In a holistic approach, we analyze how the network performance is affected with the tuning of parameters and mechanisms across multiple layers of the ZigBee protocol stack and investigate possible performance gains by implementing and testing alternative settings. The evaluations are carried out in a testbed of 57 TelosB motes. The results show that considerable performance improvements...

12. Multi-objective optimization of WLAN associations with improved handover costs - Zola, Enrica Valeria; Barceló Arroyo, Francisco; Kassler, Andreas
The deployment of a large number of access points in public areas presents a new paradigm in which a given station may be served by more than one access point at a time. Recently, a network model has been proposed to derive the optimal association strategy for the stations by solving a linear optimization problem. According to that model, a station cannot download data while performing a handover. In this letter, we demonstrate that, even in static conditions (i.e., no mobility and constant load in the cell), an association strategy can force a handover. We thus propose a multi-objective optimization...

13. Stochastic estimation of the Frobenius norm in the ACA convergence criterion - Heldring, Alexander; Úbeda Farré, Eduard; Rius Casals, Juan Manuel
The adaptive cross approximation (ACA) algorithm has been used in many fast Integral Equation solvers for electromagnetic Radiation and Scattering problems. It efficiently computes a low rank approximation to the interaction matrix between mutually distant parts of a scattering object. The ACA is an iterative algorithm that needs an accurate and efficient convergence criterion. The evaluation of this criterion may consume a considerable part of the computational resources. This communication presents an efficient new way to evaluate the convergence criterion, using a stochastic approach.

14. On the network convergence process in RPL over IEEE 802.15.4 multihop networks: improvement and trade-offs - Kermajani, Hamidreza; Gómez Montenegro, Carlos
The IPv6 Routing Protocol for Low-power and Lossy Networks (RPL) has been recently developed by the Internet Engineering Task Force (IETF). Given its crucial role in enabling the Internet of Things, a significant amount of research effort has already been devoted to RPL. However, the RPL network convergence process has not yet been investigated in detail. In this paper we study the influence of the main RPL parameters and mechanisms on the network convergence process of this protocol in IEEE 802.15.4 multihop networks. We also propose and evaluate a mechanism that leverages an option available in RPL for accelerating the...

15. Token-MAC: A fair MAC protocol for passive RFID systems - Chen, Li; Seyfettin Demirkol, Ilker; Heinzelman, Wendi
Passive RFID systems used for inventory management and asset tracking typically utilize contention-based MAC protocols, such as the standard C1G2 protocol. Although the C1G2 protocol has the advantage that it is easy to implement, it suffers from unfairness and relatively low throughput when the number of tags in the network increases. This paper proposes a token-based MAC protocol called Token-MAC for passive RFID systems, which aims a) to provide a fair chance for tags in the network to access the medium without requiring synchronization of the tags, b) to increase the overall throughput, i.e., the tag rate, and c) to...

16. Cloud-based extension for Community-Lab - Selimi, Mennan; Florit Lopez, Jorge Luis; Vega d'Aurelio, Davide; Meseguer Pallarès, Roc; López Berga, Ester; Khan, Muhammad Amin; Neumann, Axel; Freitag, Fèlix; Navarro Moldes, Leandro; Baig Viñas, Roger; Escrich, Pau; Moll, Agusti; Pueyo, Roguer; Vilalta, Ivan; Aymerich, Marc; Lamora, Santiago
Community-Lab is an open, distributed infrastructure for researchers to carry out experiments within wireless community networks. Community networks are an emergent model of infrastructures built with off-the-shelf communication equipment that aims to satisfy a community's demand for Internet access and ICT services. Community-Lab consists of more than 100 nodes that are integrated in existing community networks, thus giving researchers access to community networks and allowing them to conduct experimental evaluation of routing protocols, services and applications deployed there. Community networks have now the opportunity to extend the collaborative network building to the next level, that is, building collaborative services implemented...

17. A model for revocation forecasting in public-key infrastructures - Hernández Gañan, Carlos; Mata Diaz, Jorge; Muñoz Tapia, José Luis; Esparza Martín, Óscar; Alins Delgado, Juan José
One of the hardest tasks of a certification infrastructure is to manage revocation. This process consists in collecting and making the revocation status of certificates available to users. Research on this topic has focused on the trade-offs that different revocation mechanisms offer. Much less effort has been conducted to understand and model real-world revocation processes. For this reason, in this paper, we present a novel analysis of real-world collected revocation data and we propose a revocation prediction model. The model uses an autoregressive integrated moving average model. Our prediction model enables certification authorities to forecast the number of revoked certificates...

18. Advanced radar geosynchronous observation system: ARGOS - Monti Guarnieri, Andrea; Broquetas Ibars, Antoni; Recchia, Andrea; Rocca, Fabio; Ruiz Rodon, Josep
The Advanced Radar Geosynchronous Observation System is proposed to be a multiple-input–multiple-output synthetic aperture radar (SAR) system hosted on a swarm of minisatellites in quasi-geostationary orbits. The system is made of N iso-frequency sensors, each of them transmitting and receiving the signals. The system would combine the continuous imaging capabilities of a geostationary SAR, gaining a factor N^{2} in signal-to-noise ratio (SNR). The real aperture would be achievable in \sim 40 min, enabling applications so far unseen, such as monitoring fast deformations, landslides, and other applications for emergency and security. Still, the SNR of the long acquisition time would be...

19. Noise characterization of an atomic magnetometer at sub-millihertz frequencies - Mateos, I.; Patton, B; Zhivun, E; Budker, D; Wurm, D; Ramos Castro, Juan José
Noise measurements have been carried out in the LISA bandwidth (0.1-100 mHz) to characterize an all-optical atomic magnetometer based on nonlinear magneto-optical rotation. This was done in order to assess if the technology can be used for space missions with demanding low-frequency requirements like the LISA concept. Magnetometry for low-frequency applications is usually limited by 1/f noise and thermal drifts, which become the dominant contributions at sub-millihertz frequencies. Magnetic field measurements with atomic magnetometers are not immune to low-frequency fluctuations and significant excess noise may arise due to external elements, such as temperature fluctuations or intrinsic noise in the electronics....

20. New sleep transition indexes for describing altered sleep in SAHS - Urra, Oiane; Jané Campos, Raimon
Peer Reviewed

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