Funding for this research was provided by:
Shenzhen Science, Technology and Innovation Commission (JCYJ20150630115257902)
the Research Grants Council of the Hong Kong Special Administrative Region (ITS/339/13FX)
Hong Kong Polytechnic University (RUK0)
Article History
Received: 19 October 2016
Accepted: 14 January 2018
First Online: 27 February 2018