http://hdl.handle.net/10016/14137 2013-05-21T10:34:36Z http://hdl.handle.net/10016/16217 Title: Fair design of plug-in electric vehicles aggregator for V2G regulation Author(s): Escudero-Garzás, J. Joaquín; García-Armada, Ana; Seco-Granados, Gonzalo Abstract: Plug-in electric vehicles (PEVs) have recently attracted much attention due to their potential to reduce CO2 emissions and transportation costs and can be grouped into entities (aggregators) to provide ancillary services such as frequency regulation. In this paper, the application of aggregators to frequency regulation by making fair use of their energy storage capacity is addressed. When the power grid requires frequency regulation service to the aggregator to adjust the grid frequency, the PEVs participating in providing the service can either draw energy (as it is usually done to charge the vehicle) or deliver energy to the grid by means of the vehicle-to-grid (V2G) interface. Under the general framework of optimizing the aggregator profit, different methods, such as state-dependent allocation and the water-filling approach, are proposed to achieve a final state of charge (SOC) of the PEVs that satisfy the desired fairness criteria once the regulation service has been carried out. 2012-09-30T22:00:00Z http://hdl.handle.net/10016/14602 Title: Field measurements and guidelines for the application of wireless sensor networks to the environment and security Author(s): Gil-Jiménez, Víctor P.; García-Armada, Ana Abstract: Frequently, Wireless Sensor Networks (WSN) are designed focusing on applications and omitting transmission problems in these wireless networks. In this paper, we present a measurement campaign that has been carried out using one of the most commonly used WSN platforms, the micaZ from Crossbow°c . Based on these measurements, some guidelines to deploy a robust and reliable WSN are provided. The results are focused on security and environmental applications but can also be extrapolated to other scenarios. A main conclusion that can be extracted is that, from the transmission point of view, a dense WSN is one of the best choices to overcome many of the transmission problems such as the existence of a transitional region, redundance, forwarding, obstructions or interference with other systems. 2009-12-17T23:00:00Z http://hdl.handle.net/10016/14425 Title: Reduction of power envelope fluctuations in OFDM signals by using neural networks Author(s): Jabrane, Younes; Gil-Jiménez, Víctor P.; García-Armada, Ana; Ait Es Said, Brahim; Ait Ouahman, Abdellah Abstract: One of the main drawbacks of Orthogonal Frequency Division Multiplexing (OFDM) are the large fluctuations of its power envelope. In this letter, a novel and efficient scheme based on Multilayer Perceptron (MLP) Neural Networks (NN) is proposed. The NN synthesizes the Active Constellation Expansion - (ACE) technique which is able to drastically reduce envelope fluctuations. This is achieved with much lower complexity, faster convergence, and better performance compared to previously available methods. 2010-06-30T22:00:00Z http://hdl.handle.net/10016/14426 Title: Effects of channel estimation on multiuser virtual MIMO-OFDMA relay-based networks Author(s): Gil-Jiménez, Víctor P.; Ribeiro, Carlos; Gameiro, Atilio; García-Armada, Ana Abstract: A practical multiuser cooperative transmission scheme denoted as Virtual Maximum Ratio Transmission (VMRT) for multiple-input multiple-output-orthogonal frequency division multiple access (MIMO-OFDMA) relay-based networks is proposed and evaluated in the presence of a realistic channel estimation algorithm and using low-density parity-check (LDPC) codes. It is shown that this scheme is robust against channel estimation errors. It offers diversity and array gain, keeping the complexity low with a multiuser and multiantenna channel estimation algorithm that is simple and efficient. In addition, the combination with LDPC codes provides improved gains; diversity gains larger than 6 dB can be easily obtained with a reduced number of relays. Thus, this scheme can be used to extend coverage or increase system throughput by using simple cooperative OFDMA-based relays. 2010-11-10T23:00:00Z