Funding for this research was provided by:
National Science Foundation (CCF-0724979)
National Science Foundation (CCF-1421211)
National Science Foundation (OCI-1148125)
Fundação para a Ciência e a Tecnologia (SFRH/BD/47800/2008)
Article History
Received: 5 November 2014
Revised: 4 August 2015
Accepted: 18 August 2015
First Online: 7 September 2015