No review has been posted.
No open issue.
School of Information Science and Technology, Xiamen University, Xiamen, Fujian 361005, China
The work was supported by the Natural Science Foundation of China (Nos. 61370010, 31271405, 81101115), the Natural Science Foundation of Fujian Province of China (Nos. 2011J01371, 2011J05158) and the 2013 Program for New Century Excellent Talents in Fujian Province University.