Submitted on: 26 December 2004.
Revised on: 22 January 2005.
Accepted on: 06 March 2005.
___________________COMMUNICATIONS OF THE ACM---ASSOC COMPUTING MACHINERY
Submitted on: 23 August 2013.
Revised on: 02 October 2013.
Accepted on: 21 November 2013.
___________________COMMUNICATIONS OF THE ACM---ASSOC COMPUTING MACHINERY
http://reply.papertrans.cn/1/61/6034/6034-13.png
Submitted on: 13 June 2002.
Revised on: 08 July 2002.
Accepted on: 09 August 2002.
___________________COMMUNICATIONS OF THE ACM---ASSOC COMPUTING MACHINERY
http://reply.papertrans.cn/1/61/6034/6034-15.png
Submitted on: 08 October 2001.
Revised on: 06 November 2001.
Accepted on: 23 December 2001.
___________________COMMUNICATIONS OF THE ACM---ASSOC COMPUTING MACHINERY
http://reply.papertrans.cn/1/61/6034/6034-17.png
http://reply.papertrans.cn/1/61/6034/6034-18.png
Submitted on: 14 September 2015.
Revised on: 28 November 2015.
Accepted on: 09 December 2015.
___________________COMMUNICATIONS OF THE ACM---ASSOC COMPUTING MACHINERY
Submitted on: 13 October 2009.
Revised on: 08 February 2010.
Accepted on: 01 April 2010.
___________________COMMUNICATIONS OF THE ACM---ASSOC COMPUTING MACHINERY