^pof;
Mechanical;
System;
Engineering,;
Faculty;
of;
Engineering,;
Gunma;
University,;
Kiryu;
376-8515,;
Japan;
^pof;
Mechanical;
Engineering,;
School;
of;
Mechanical;
Engineering;
and;
Automation,;
Dalian;
Polytechnic;
University,;
Dalian;
116034,;
PRO;