$B66IZ$G$9(B $B!!I%ED$5$s(B $B!!#1=54V$[$I%a!<%kFI$a$J$C$+$?$N$GCY$l$^$7$??=$7Lu$J$$$G$9(B $B!!!!(B > >$B5~ET#O#F#M$r2?;~$KCW$7$^$7$g$&$+!)!!3'MM$N$4ET9g$O!)(B >$B$G$O!#(B $B!!;d$b$*K_L@$1$,!!ET9gNI$$$G$9!!!!!!(B $B!!(B ---- $B66IZ6=@k(B o-hashitomi@iae.kyoto-u.ac.jp