http://reply.papertrans.cn/3/280/27959/27959-31.png
http://reply.papertrans.cn/3/280/27959/27959-32.png
Submitted on: 28 July 2012.
Revised on: 05 September 2012.
Accepted on: 10 September 2012.
SIGMOD RECORD
Submitted on: 24 January 2012.
Revised on: 21 February 2012.
Accepted on: 09 March 2012.
SIGMOD RECORD---ASSOC COMPUTING MACHINERY
Submitted on: 11 April 2016.
Revised on: 21 May 2016.
Accepted on: 09 June 2016.
SIGMOD RECORD
http://reply.papertrans.cn/3/280/27959/27959-36.png