Recursos de colección

Archivo Digital UPM (107.543 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Telecomunicaciones

Mostrando recursos 1 - 20 de 3.451

  1. A multi functional plug-in for exergames

    Eckert, Martina; Gómez Martinho, Ignacio; Meneses Chaus, Juan Manuel; Martínez Ortega, José Fernán
    This paper describes the development of a software complement for Blender (a freely available animation software) which allows to insert motion data obtained from a motion capture camera device. The main target is to provide Blender with a tool to develop exergames, i.e. serious games for performing physical exercises, which are fully adaptive to the user?s needs and capabilities, especially addressing chronical patients or handicapped. The plugin incorporates both: motion control and recording, allowing to store user movements. Transmission is realized via the OSC (Open Sound Control) protocol. The tool is still under development, here a first version is presented...

  2. Performance comparison of SVD- and GMD-assisted MIMO systems

    Ahrens, Andreas; Benavente Peces, César; Aboltins, Arturs
    Singular-value decomposition (SVD)-based multiple-input multiple-output (MIMO) systems have attracted a lot of attention in the wireless community where the whole MIMO channel is decomposed into a number of unequally weighted independent single-input single-output (SISO) channels. The unequal weighting of the SISO channels has led to intensive research on bit- and power allocation even in MIMO channel situations with poor scattering conditions identified as the antenna correlation effect. In this situation, the unequal weighting of the SISO channels becomes even much stronger. In comparison to the SVD-assisted MIMO transmission, geometric mean decomposition (GMD)-based MIMO systems are able to compensate for the...

  3. High-power UV-LED degradation: Continuous and cycled working condition influence

    Arques Orobón, Francisco José; Núñez Mendoza, Neftalí; Vázquez López, Manuel; González Posadas, Vicente; Segura Antunez, C.
    High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal...

  4. Learning English is fun! Increasing motivation through video games

    Osma Ruiz, Víctor José; Saenz Lechón, Nicolás; Gutiérrez Arriola, Juana María; Argüelles Álvarez, Irina; Fraile Muñoz, Rubén; Marcano Ganzo, Roberto
    In this paper we present a study made with 16 university students with different levels of proficiency in English, who were divided into two groups: those with a basic level (B1 or lower) and those who had an advanced one (B2 or higher). These two groups had the opportunity to get to know and interact with a serious game developed in the ?Universidad Politécnica de Madrid? with the aim of helping in the teaching-learning process of English as a foreign language. Before and after the interaction, all students were interviewed on various aspects related to the English learning process. Although...

  5. Promocionar y coordinar la investigación científica y técnica

    Martín Pereda, José Antonio
    Análisis de algunos aspectos del Proyecto de Ley sobre Investigación Científica y Técnica, tales como la financiación regular de los equipos de investigación o la promoción de la participación de la comunidad científica, entre otros.

  6. Las nuevas tecnologías como variante clandestina de la postmodernidad

    Martín Pereda, José Antonio
    Reflexión sobre el estado de las "nuevas tecnologías" en el año 1987 en nuestro país. Se defiende la importancia de emplear dichas tecnologías en mejorar los servicios a los ciudadanos.

  7. Modeling and Design of Ring Oscillators and their Application in Radiation Environments

    Agustín Sáenz, Javier
    Humanity has always looked to the sky; first with mystery, later with curiosity. That curiosity led us to the desire of exploration of the unknown worlds. Although it was not immediate, as our limitations tend to keep us with our feet on the ground, we developed the necessary technology to see our dreams came true. This technology has seen its maximum development during the last half century lying on the evolution of electronic systems. As happens with other implicated sciences, overcoming the challenges presented by electronics along this path has not been a bed of roses. Many problems appeared from...

  8. Nueva técnica de modulación de excitación para sistemas EER

    Tena Ramos, David; Ortega González, Francisco Javier; Patiño Gómez, Moises; Pardo Martín, José Manuel
    This paper shows a novel drive modulation technique applied to a high power, high efficiency, linear Envelope Elimination and Restoration (EER) amplifier for L-Band. It comprises a mixed-mode suboptimum Class-E / Class-A wideband RF amplifier based on a dual GaN HEMT for RF carrier amplification and a high efficiency, high switching frequency, multi-phase, buck power converter based on Silicon LDMOS transistors to work as a modulator (or envelope amplifier). The linearity and power gain for this EER amplifier is improved by means of a new digital drive modulation technique and digital predistortion (DPD) to achieve linearity performances equivalent or better...

  9. Communication range dynamics using an energy saving self-adaptive transmission power controller in a wireless sensor network

    Lucas Martínez, Néstor; Martinez Ortega, José Fernán; Hernandez Diaz, Vicente; Toro Matamoros, Raúl del
    The deployment of the nodes in a Wireless Sensors and Actuators Network (WSAN) is typically restricted by the sensing and acting coverage. This implies that the locations of the nodes may be, and usually are, not optimal from the point of view of the radio communication. And also when the transmission power is tuned for those locations, there are other unpredictable factors that can cause connectivity failures, like interferences, signal fading due to passing objects, and of course, radio irregularities. A control based self-adaptive system is a typical solution to improve the energy consumption while keeping a good connectivity. In...

  10. Dynamic management of multikernel multithread accelerators using dynamic partial reconfiguration

    Rodríguez Medina, Alfonso; Valverde Alcalá, Juan; Torre Arnanz, Eduardo de la; Riesgo Alcaide, Teresa
    Ever demanding systems with restricted resources face increasingly complex applications. Additionally, changeable environments modify working conditions over time. Therefore, a dynamic resource management is required in order to provide adaptation capabilities. By using ARTICo3, a bus-based architecture with reconfigurable slots, this adaptation is accomplished in three different but dependent areas: Consumption, Confidentiality and fault tolerance, and Computation. The proposed resource management strategies rely on an architecture and a model of computation that make execution configuration to be application-independent, but context-aware, since a CUDA-like execution model is used. The inherent and explicit application-level parallelism of multithreaded CUDA kernels is used to...

  11. A run time adaptive architecture to trade-off performance for fault tolerance applied to a DVB on-board processor

    Veljković, Filip; Riesgo Alcaide, Teresa; Torre Arnanz, Eduardo de la; Regada, Raúl; Berrojo, Luis
    Reliability is one of the key issues in space applications. Although highly flexible and generally less expensive than predominantly used ASICs, SRAM-based FPGAs are very susceptible to radiation effects. Hence, various fault tolerant techniques have to be applied in order to handle faults and protect the design. This paper presents a reconfigurable on-board processor capable of run-time adaptation to harsh environmental conditions and different functional demands. Run-time reconfigurability is achieved applying two different reconfiguration methodologies. We propose a novel self-reconfigurable architecture able to on demand duplicate or triplicate part of the design in order to form DMR and TMR structures....

  12. Measurements of a MIMO train-to-wayside communication system on tunnels

    Moreno García-Loygorri, Juan; Haro Ariet, Leandro de; Rodríguez, Carlos; Cuéllar Navarrete, Luis; Riera Salis, Jose Manuel
    This paper presents a deep insight on a real implementation of a train-to-wayside radio on subway tunnels that makes use of a 2x2 MIMO-OFDM setup. The following parameters on the performance of such a system are investigated: polarization diversity, antenna separation, tunnel cross-section influence and MIMO capacity. Moreover, two different channel matrices have been calculated, assuming uniform power allocation and performing the waterfilling algorithm. Finally, the purpose of this paper is to evaluate the feasibility of a real MIMO-based train-to-wayside broadband radio. Measurements were carried out on Line 3 of Metro de Madrid, Spain.

  13. Broadband radio communications in subway stations and tunnels

    Lei, Zhang; Fernández Fernández, Jean Raphael; Briso Rodríguez, César; Rodríguez, Carlos; Moreno García-Loygorri, Juan; Guan, Ke
    Broadband radio communication systems are very important for railway traffic control systems and passengers network services. Nowadays, even though 4G LTE (Long Term Evolution) has deployed for commercial use with excellent results in open areas, it is still lack of knowledge regarding to how such broadband signals propagate inside complex environments with many complex structures that affect propagation such as subway tunnels and stations. For this reason, the aim of the presented measurements in this paper is to model the response of the broadband channel at 1000 MHz and 2450 MHz in the subway environments. These measurements focus on three...

  14. Platform for on-board real-time detection of wet, icy and snowy roads, using tyre/road noise analysis

    Alonso Fernández, Jesús; López Navarro, Juan Manuel; Pavón García, Ignacio; Asensio Rivera, César; Arcas Castro, Guillermo de
    Descripción de la plataforma hardware desarrollada para la discriminación del estado de la carretera (seco, mojado, helado, nevado) mediante el uso de análisis acústico y máquinas de vectores soporte. ABSTRACT In this paper, a new approach capable of detecting water, ice and snow on the road surface is shown, focusing on the hardware needed for the practical implementation. Proposed platform uses a simple microphone and a general purpose microcontroller. The system is tightly integrated with vehicle ECUs (Electronic Control Units). A CAN bus allows it to read some of the variable dynamics provided by the sensors already installed in virtually...

  15. Analysis of the effect of modulation delays on the size of the output capacitor

    Cortés González, Jorge; Svikovic, Vladimir; Alou Cervera, Pedro; Oliver Ramírez, Jesús Angel; Cobos Marquez, Jose Antonio
    Constant frequency (PWM), constant on-time (COT) and constant off-time modulations exhibit inherent delays where the controller is unable to respond instantaneously. These delays can increase the required size of the output capacitor to meet dynamic requirements in applications with high demanding load such as the supply of microprocessors. This paper analyzes the minimum required output filter (output inductor and output capacitor) to meet a given specification and quantifies the effect that different modulations have in the minimum size of the output capacitor. The paper also shows a novel technique to mitigate the delays of the modulations by means of synchronizing...

  16. Modelling and planning reliable wireless sensor networks based on multi-objective optimization genetic algorithm with changeable length

    He, Danping; Mujica Rojas, Gabriel Noe; Portilla Berrueco, Jorge; Riesgo Alcaide, Teresa
    Wireless sensor networks (WSN) have shown their potentials in various applications, which bring a lot of benefits to users from different working areas. However, due to the diversity of the deployed environments and resource constraints, it is difficult to predict the performance of a topology. Besides the connectivity, coverage, cost, network longevity and service quality should all be considered during the planning procedure. Therefore, efficiently planning a reliable WSN is a challenging task, which requires designers coping with comprehensive and interdisciplinary knowledge. A WSN planning method is proposed in this work to tackle the above mentioned challenges and efficiently deploying...

  17. Echegaray, divulgador de la ciencia

    Martín Pereda, José Antonio
    Se presenta la faceta de Echegaray como divulgador de la Ciencia y la Tecnología, faceta a la que dedicó gran parte de su vida, con una producción muy extensa. Se plantea la forma que tenía para estructurar sus artículos, muy semejante a la que tenía para el desarrollo de sus obras dramáticas, y se resalta su peculiar sentido del humor. Se ofrecen algunos ejemplos de ambos aspectos.

  18. Measurement and analysis of extra propagation loss of tunnel curve

    Ai, Bo; Guan, Ke; Zhong, Zhangdui; López, Carlos F.; Lei, Zhang; Briso Rodríguez, César; He, Ruisi
    Wave propagation experiences extra loss in curved tunnels, which is highly desired for network planning. Extensive narrow-band propagation measurements are made in two types of Madrid subway tunnels (different cross sections and curvatures) with various configurations (different frequencies and polarizations). A ray tracer validated by the straight and curved parts of the measuring tunnels is employed to simulate the reference received signal power by assuming the curved tunnel to be straight. By subtracting the measured received power in the curved tunnels from the simulated reference power, the extra loss resulting from the tunnel curve is extracted. Finally, this paper presents the...

  19. Solución para garantizar la privacidad en el internet de las cosas

    Sanchez Alcon, Jose Antonio; Lopez Santidrian, Lourdes; Martinez Ortega, Jose Fernán
    Los nuevos productos y servicios de “internet de las cosas” nos harán más eficientes, con mayor capacidad de actuación y comprensión del entorno, habrá nuevas ayudas técnicas que permitirán prolongar nuestra vida activa y más. Sin embargo coexistiremos con una gran cantidad de dispositivos que recopilarán información sobre nuestra actividad, costumbres, preferencias,etc., que podrían amenazar nuestra privacidad. La desconfianza podría ser una barrera para el desarrollo pleno de estos nuevos productos y servicios. Se aporta una posible solución para la garantizar la seguridad y privacidad de los datos personales en internet de las cosas, mediante técnicas que resulten de la colaboración...

  20. Non-Cooperative target recognition by means of singular value decomposition applied to radar high resolution range profiles

    López Rodríguez, Patricia; Escot Bocanegra, David; Fernández Recio, Raúl; Bravo Muñoz, Ignacio
    Radar high resolution range profiles are widely used among the target recognition community for the detection and identification of flying targets. In this paper, singular value decomposition is applied to extract the relevant information and to model each aircraft as a subspace. The identification algorithm is based on angle between subspaces and takes place in a transformed domain. In order to have a wide database of radar signatures and evaluate the performance, simulated range profiles are used as the recognition database while the test samples comprise data of actual range profiles collected in a measurement campaign. Thanks to the modeling of...

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