Submitted on: 08 August 1999.
Revised on: 30 October 1999.
Accepted on: 10 December 1999.
___________________Journal of the Korean Statistical Society
Submitted on: 19 July 2004.
Revised on: 08 October 2004.
Accepted on: 07 November 2004.
___________________Journal of the Korean Statistical Society
Submitted on: 24 January 2003.
Revised on: 02 March 2003.
Accepted on: 17 March 2003.
___________________Journal of the Korean Statistical Society
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Submitted on: 16 May 2013.
Revised on: 30 August 2013.
Accepted on: 25 September 2013.
___________________Journal of the Korean Statistical Society
Submitted on: 14 April 2010.
Revised on: 08 June 2010.
Accepted on: 07 July 2010.
___________________Journal of the Korean Statistical Society
http://reply.papertrans.cn/2/198/19793/19793-17.png
http://reply.papertrans.cn/2/198/19793/19793-18.png
Submitted on: 04 June 1999.
Revised on: 12 September 1999.
Accepted on: 23 September 1999.
___________________Journal of the Korean Statistical Society
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