Submitted on: 05 June 2008.
Revised on: 22 September 2008.
Accepted on: 19 October 2008.
___________________IEEE COMPUTER GRAPHICS AND APPLICATIONS
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Submitted on: 06 September 2012.
Revised on: 24 November 2012.
Accepted on: 11 January 2013.
___________________IEEE COMPUTER GRAPHICS AND APPLICATIONS
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