Funding for this research was provided by:
Division of Electrical, Communications and Cyber Systems (CIF-1618653)
Ministerio de Economía, Industria y Competitividad, Gobierno de España (TEC2016-75067-C4-3-R)
Received: 30 July 2018
Accepted: 14 December 2018
First Online: 14 January 2019
: The authors declare that they have no competing interests.
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