realizing the future can only be possible if the current and the past are clear. Hence, section 2 of this paper rectifies history of events and researches in the field in the period of 2002 to 2007 while section 3 concentrates only on recent research works in the period of 2008 and 2013 and offers categorization of major fields and a statistical comparison between industrial and academic in the field. Finally, we look into overlooked issues and offer several future research directions in the field.