Submitted on: 29 July 2004.
Revised on: 09 September 2004.
Accepted on: 04 November 2004.
___________________IEEE ELECTRICAL INSULATION MAGAZINE
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Submitted on: 24 July 1998.
Revised on: 10 September 1998.
Accepted on: 31 October 1998.
___________________IEEE ELECTRICAL INSULATION MAGAZINE