Funding for this research was provided by:
Fundamental Research Funds for the Central Universities (NUAA NS2015099)
Text and Data Mining valid from 2018-05-11
Received: 13 February 2018
Accepted: 9 April 2018
First Online: 11 May 2018
Change Date: 29 September 2018
Change Type: Correction
Change Details: The original version of this article unfortunately contains mistakes. Below are the corrections: 1) In Equation 9, a “minus (-)” sign is missing in the second line and a “less-than or equal to (≤)” sign was captured in the third line instead of the correct “less than sign (<)”.
Compliance with Ethical Standards
: The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.