Browsing by Author "Insausti, Xabier"
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Item Algorithm for the Optimal Design of a Fault-Tolerant Aircraft Power Transmission Network(2022-12-01) Zarraga-Rodriguez, Marta; Insausti, Xabier; Lalanne, Fermin Rodriguez; Velasco, Javier; Gutierrez-Gutierrez, Jesus; Tecnalia Research & Innovation; DIGITAL ENERGYAircraft manufacturers aim to decrease the fuel consumption based on reducing weight and increasing the subsystem efficiency. Hence, the electric power system (EPS) acquires great relevance because it must be efficient and lightweight. Any change in the EPS must not affect the aircraft's electrical safety, which under a traditional decentralized EPS strategy is ensured by redundancy. Recently, several decentralized EPS strategies based on the introduction of multiport power converters have arisen. Such strategies meet the established safety goals since the aforementioned devices make it possible to recalculate the path to continue powering the loads in case of failure. However, the literature does not address how to connect such multiport power converters. The main contribution of this article is to present a low-complexity algorithm that minimizing the redundancy of wiring, provides a fault-tolerant power transmission network. This is done under a decentralized EPS strategy where multiport power converters are used. The proposed strategy is evaluated on Boeing 787 aircraft, where we compare the length of the cables both under a traditional decentralized network configuration (where the redundancy option is used to ensure the safety of operation) and in the network provided by our algorithm. A saving of 66.6% is obtained.Item Concurrent and distributed projection through local interference for wireless sensor networks(2012) Insausti, Xabier; Crespo, Pedro M.; Beferull, Baltasar; Del Ser, Javier; IAIn this paper we use a gossip algorithm to obtain the projection of the observed signal into a subspace of lower dimension. Gossip algorithms allow distributed, fast and efficient computations on a Wireless Sensor Network and they can be properly modified to evaluate the sought projection. By combining computation coding with gossip algorithms we proposed a novel strategy that leads to important saving on convergence time as well as exponentially decreasing energy consumption, as the size of the network increases.Item Signal shaping scheme based on the BWT for the transmission of non-binary sources with memory over the AWGN channel(2010) Crespo, Pedro M.; Insausti, Xabier; Del Ser, Javier; Gutiérrez-Gutiérrez, Jesús; IAThis paper proposes a low-complexity signal shaping scheme for the transmission of non-binary symbols generated by sources with memory over the AWGN channel. It is based on using the Burrows-Wheeler Transform (BWT) [1] and standard two dimensional (QAM) constellations. The constellation points are driven based on the first order probabilities of the BWT output symbols so that shaping gain is maximized. The proposed system is an extension of the one introduced in [2] for binary sources. To evaluate its performance, the corresponding average energy per transmitted symbol is compared with that obtained when using an ideal source encoder followed by a standard uncoded QAM transmission scheme. In addition, it is shown that the power gain ratio between both systems can be assessed based on the Kullback-Leibler divergence between the first order probability distributions of the BWT output symbols and the Maxwell-Boltzmann probability distribution, obtained under the constraint of achieving an entropy equal to the entropy-rate of the original source.Item Very short-term parametric ambient temperature confidence interval forecasting to compute key control parameters for photovoltaic generators(2022-06) Rodríguez, Fermín; Insausti, Xabier; Etxezarreta, Gorka; Galarza, Ainhoa; Guerrero, Josep M.; Tecnalia Research & Innovation; DIGITAL ENERGYIn recent years, various forecasters have been developed to decrease the uncertainty related to the intermittent nature of photovoltaic generation. While the vast majority of these forecasters are usually just focused on deterministic or probabilistic prediction points, few studies have been carried out in relation to prediction intervals. In increasing the reliability of photovoltaic generators, being able to set a confidence level is as important as the forecaster's accuracy. For instance, changes in ambient temperature or solar irradiation produce variations in photovoltaic generators’ output power as well as in control parameters such as cell temperature and open voltage circuit. Therefore, the aim of this paper is to develop a new mathematical model to quantify the confidence interval of ambient temperature in the next 10 min. Several error metrics, such as the prediction interval coverage percentage, the Winkler score and the Skill score, are calculated for 95%, 90% and 85% confidence levels to analyse the reliability of the developed model. In all cases, the prediction interval coverage percentage is higher than the selected confidence interval, which means that the estimation model is valid for practical photovoltaic applications.