P-Selectivity, Immunity, and the Power of One Bit

We prove that P-sel, the class of all P-selective sets, is EXP-immune, but is not EXP/1-immune. That is, we prove that some infinite P-selective set has no infinite EXP-time subset, but we also prove that every infinite P-selective set has some infinite subset in EXP/1. Informally put, the immunity of P-sel is so fragile that it is pierced by a single bit of information. The above claims follow from broader results that we obtain about the immunity of the P-selective sets. In particular, we prove that for every recursive function f, P-sel is DTIME(f)-immune. Yet we also prove that P-sel is not \Pi_2^p/1-immune

New Concept of PLC Modems: Multi-Carrier System for Frequency Selective Slow-Fading Channels Based on Layered SCCC Turbocodes

The article introduces a novel concept of a PLC modem as a complement to the existing G3 and PRIME standards for communications using medium- or high-voltage overhead or cable lines. The proposed concept is based on the fact that the levels of impulse noise and frequency selectivity are lower on high-voltage lines than on low-voltage ones. Also, the demands for “cost-effective” circuitry design are not so crucial as in the case of modems for low-voltage level. In contract to these positive conditions, however, there is the need to overcome much longer distances and to take into account low SNR on the receiving side. With respect to the listed reasons, our concept makes use of MCM, instead of OFDM. The assumption of low SNR is compensated through the use of an efficient channel coding based on a serially concatenated turbo code. In addition, MCM offers lower latency and PAPR compared to OFDM. Therefore, when using MCM, it is possible to excite the line with higher power. The proposed concept has been verified during experimental transmission of testing data over a real, 5 km long, 22kV overhead line

Spiking Chemical Sensor (SCS): A new platform for neuro-chemical sensing

Published versio

Waveform Approach for Assessing Conformity of CISPR 16-1-1 Measuring Receivers

An alternative approach for assessing the conformity of electromagnetic interference measuring receivers with respect to the baseline CISPR 16-1-1 requirements is proposed. The method’s core is based on the generation of digitally synthesized complex waveforms comprising multisine excitation signals and modulated pulses. The superposition of multiple narrowband reference signals populating the standard frequency bands allows for a single-stage evaluation of the receiver’s voltage accuracy and frequency selectivity. Moreover, characterizing the response of the weighting detectors using modulated pulses is more repeatable and less restrictive than the conventional approach. This methodology significantly reduces the amount of time required to complete the verification of the receiver’s baseline magnitudes, because time-domain measurements enable a broadband assessment while the typical calibration methodology follows the time-consuming narrow band frequency sweep scheme. Since the reference signals are generated using arbitrary waveform generators, they can be easily reproduced from a standard numerical vector. For different test receivers, the results of such assessment are presented in the 9 kHz–1 GHz frequency range. Finally, a discussion on the measurement uncertainty of this methodology for assessing measuring receivers is given.Postprint (author's final draft

Photonic millimeter-wave frequency multiplication based on cascaded four-wave mixing and polarization pulling

This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.005055. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] A technique for the frequency multiplication of microwave signals based on the combination of two optical nonlinear phenomena in a single nonlinear fiber is investigated. Multiple four-wave mixing is used to generate harmonics on an externally modulated optical carrier while polarization pulling through stimulated Brillouin scattering is used to filter the desired harmonics. Microwave signals in the 60 GHz region are generated showing harmonic frequency multiplication factors of up to 25 with a suppression of undesired harmonics better than 20 dB. © 2012 Optical Society of America.This research was supported in part by the Spanish Ministerio de Economia y Competitividad through TEC2009-08078 and TEC2012-35797 projects.Vidal Rodriguez, B. (2012). Photonic millimeter-wave frequency multiplication based on cascaded four-wave mixing and polarization pulling. Optics Letters. 37(24):25478-25488. https://doi.org/10.1364/OL.37.005055S25478254883724Kawanishi, T., Oikawa, S., Yoshiara, K., Sakamoto, T., Shinada, S., & Izutsu, M. (2005). Low noise photonic Millimeter-wave generation using an integrated reciprocating optical Modulator. IEEE Photonics Technology Letters, 17(3), 669-671. doi:10.1109/lpt.2004.842377Li, W., & Yao, J. (2010). Investigation of Photonically Assisted Microwave Frequency Multiplication Based on External Modulation. IEEE Transactions on Microwave Theory and Techniques, 58(11), 3259-3268. doi:10.1109/tmtt.2010.2075671Vidal, B., Huggard, P. G., Ellison, B. N., & Gomes, N. J. (2010). Optoelectronic generation of W-band millimetre-wave signals using Brillouin amplification. Electronics Letters, 46(21), 1449. doi:10.1049/el.2010.2310Wiberg, A., Perez-Millan, P., Andres, M. V., & Hedekvist, P. O. (2006). Microwave-photonic frequency multiplication utilizing optical four-wave mixing and fiber Bragg gratings. Journal of Lightwave Technology, 24(1), 329-334. doi:10.1109/jlt.2005.860164Wang, Q., Rideout, H., Zeng, F., & Yao, J. (2006). Millimeter-Wave Frequency Tripling Based on Four-Wave Mixing in a Semiconductor Optical Amplifier. IEEE Photonics Technology Letters, 18(23), 2460-2462. doi:10.1109/lpt.2006.886826Li, Y., Naderi, N. A., Kovanis, V., & Lester, L. F. (2010). Enhancing the 3-dB Bandwidth via the Gain-Lever Effect in Quantum-Dot Lasers. IEEE Photonics Journal, 2(3), 321-329. doi:10.1109/jphot.2010.2046481McKinstrie, C. J., & Raymer, M. G. (2006). Four-wave-mixing cascades near the zero-dispersion frequency. Optics Express, 14(21), 9600. doi:10.1364/oe.14.009600Cerqueira Sodre, A., Chavez Boggio, J. M., Rieznik, A. A., Hernandez-Figueroa, H. E., Fragnito, H. L., & Knight, J. C. (2008). Highly efficient generation of broadband cascaded four-wave mixing products. Optics Express, 16(4), 2816. doi:10.1364/oe.16.002816Wise, A., Tur, M., & Zadok, A. (2011). Sharp tunable optical filters based on the polarization attributes of stimulated Brillouin scattering. Optics Express, 19(22), 21945. doi:10.1364/oe.19.021945Hansryd, J., Andrekson, P. A., Westlund, M., Jie Li, & Hedekvist, P.-O. (2002). Fiber-based optical parametric amplifiers and their applications. IEEE Journal of Selected Topics in Quantum Electronics, 8(3), 506-520. doi:10.1109/jstqe.2002.101635

Development of a dc-ac power conditioner for wind generator by using neural network

This project present of development single phase DC-AC converter for wind generator application. The mathematical model of the wind generator and Artificial Neural Network control for DC-AC converter is derived. The controller is designed to stabilize the output voltage of DC-AC converter. To verify the effectiveness of the proposal controller, both simulation and experimental are developed. The simulation and experimental result show that the amplitude of output voltage of the DC-AC converter can be controlled

Performance evaluation of channel estimation techniques for a mobile fourth generation wide area OFDM system

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