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Priolo A.,Third University of Rome | Gasparri A.,Third University of Rome | Montijano E.,Centro Universitario Of La Defensa Cud | Montijano E.,University of Zaragoza | Sagues C.,University of Zaragoza
Automatica | Year: 2014

In this work we propose a distributed algorithm to solve the discrete-time average consensus problem on strongly connected weighted digraphs (SCWDs). The key idea is to couple the computation of the average with the estimation of the left eigenvector associated with the zero eigenvalue of the Laplacian matrix according to the protocol described in Qu et al. (2012). The major contribution is the removal of the requirement of the knowledge of the out-neighborhood of an agent, thus paving the way for a simple implementation based on a pure broadcast-based communication scheme. © 2014 Elsevier Ltd. All rights reserved. Source


Montijano E.,Centro Universitario Of La Defensa Cud | Montijano J.I.,University of Zaragoza | Sagues C.,University of Zaragoza
IEEE Transactions on Signal Processing | Year: 2013

In this paper we analyze the use of Chebyshev polynomials in distributed consensus applications. It is well known that the use of polynomials speeds up the convergence to the consensus in a significant way. However, existing solutions only work for low degree polynomials and require the topology of the network to be fixed and known. We propose a distributed algorithm based on the second order difference equation that describes the Chebyshev polynomials of first kind. The contributions of our algorithm are three: (i) Since the evaluation of Chebyshev polynomials is stable, there is no limitation in the degree of the polynomial. (ii) Instead of the knowledge of the whole network topology, it only requires a partial knowledge or an approximation to it. (iii) It can be applied to time varying topologies. In the paper we characterize the main properties of the algorithm for both fixed and time-varying communication topologies. Theoretical results, as well as experiments with synthetic data, show the benefits of using our algorithm compared to existing methods.© 2012 IEEE. Source


Priolo A.,Third University of Rome | Gasparri A.,Third University of Rome | Montijano E.,Centro Universitario Of La Defensa Cud | Sagues C.,University of Zaragoza
Proceedings of the American Control Conference | Year: 2013

In this work we propose a decentralized algorithm for balancing a strongly connected weighted digraph. This algorithm relies on the decentralized estimation of the left eigenvector associated to the zero structural eigenvalue of the Laplacian matrix. The estimation is performed through the distributed computation of the powers of the Laplacian matrix itself. This information can be locally used by each agent to modify the weights of its incoming edges so that their sum is equal to the sum of the weights outgoing this agent, i.e., the weighted digraph is balanced. Simulation results are proposed to corroborate the theoretical results. © 2013 AACC American Automatic Control Council. Source


Altabas J.A.,Aragon Institute of Engineering Research | Izquierdo D.,Aragon Institute of Engineering Research | Izquierdo D.,Centro Universitario Of La Defensa Cud | Lazaro J.A.,Polytechnic University of Catalonia | And 3 more authors.
Optics Express | Year: 2016

1Gbps full-duplex optical links for 6.25GHz ultra dense WDM frequency slots are demonstrated and optimized for cost-effective metroaccess networks. The OLT-ONU downlinks are based on 1Gbps Nyquist- DPSK using MZM and single-detector heterodyne reception obtaining a sensitivity of -52dBm. The ONU-OLT uplinks are based on 1Gbps NRZDPSK by directly phase modulated DFB and also single-detector heterodyne reception obtaining same sensitivity of -52dBm. The power budget of full-duplex link is 43dB. These proposed links can provide service to 16 (32) users at each 100 (200) GHz WDM channel. © 2016 Optical Society of America. Source


Calvo-Lopez A.,Autonomous University of Barcelona | Ymbern O.,Autonomous University of Barcelona | Izquierdo D.,Centro Universitario Of La Defensa Cud | Izquierdo D.,Aragon Institute of Engineering Research | Alonso-Chamarro J.,Autonomous University of Barcelona
Analytica Chimica Acta | Year: 2016

The design, construction and evaluation of a low cost, cyclic olefin copolymer (COC)-based continuous flow microanalyzer, with optical detection, to monitor carbon dioxide in bottled wines and beers as well as in fermentation processes, is presented. The microsystem, constructed by computer numerically controlled (CNC) micromilling and using a multilayer approach, integrates microfluidics, gas-diffusion module and an optical flow-cell in a single polymeric substrate. Its size is slightly bigger than a credit card, exactly 45 × 60 × 4 mm in the microfluidic and diffusion module zone and 22.5 × 40 × 3 mm in the flow-cell zone. The gas-diffusion module is based on a hydrophobic polyvinylidene fluoride (PVDF) membrane, which allows the transfer of the carbon dioxide present in the sample to a bromothymol blue (BTB) pH-sensitive acceptor solution, where the color change is measured optically. The detection system consisted of a LED with an emission peak at 607 nm and a photodiode integrated in a printed circuit board (PCB). The obtained analytical features after the optimization of the microfluidic platform and hydrodynamic variables are a linear range from 255 to 10000 mg L−1 of CO2 and a detection limit of 83 mg L−1 with a sampling rate of 30 samples h−1. © 2016 Elsevier B.V. Source

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