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Submitted on: 25 April 2010.
Revised on: 12 August 2010.
Accepted on: 03 October 2010.
___________________Frontiers of Information Technology & Electronic Engineering
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Submitted on: 18 July 2012.
Revised on: 13 September 2012.
Accepted on: 15 October 2012.
___________________Frontiers of Information Technology & Electronic Engineering