$B $B?M2A(B $B>e$X(B: $BI>2AJ}K!(B $BLa$k(B: $BI>2AJ}K!(B   $BL\

$B<+F0I>2A(B

$B5!3#K]Lu%7%9%F%`$NK]Lu@:EY$r<+F0E*$KI>2A$9$k2AK!$K$OB?$/$NJ}K!$,$"$k$,!$K\8&5f$G$O!$(BBLEU(BiLingual Evaluation Understudy)[14]$B!$(BNIST[15]$B!$(BMETEOR(Metric for Evaluation of Translation with Explicit ORdering)[16]$B$rMQ$$$k!%(B

• BLEU[14]
  BLEU$B$O!$5!3#K]Lu$NJ,Ln$K$*$$$F!$:G$b0lHLE*$J<+F0I>2A4p=`$G$"$k!%(BBLEU$B$O!$(Bn-gram$B%^%C%AN($K4p$E$/
  

  $$BLEU = BPexp\left(\sum_{n=1}^{N}w_{n}\log p_{n}\right)$$ (26)

  
  

  
  

  $$w_{n} = 1 / N$$ (27)

  
  

  
  

  $$p_{n} = \frac{\sum_{i}$B=PNOJ8Cf(Bi$B$H@52rJ8Cf(Bi$B$G0lCW$7$?(Bn-gram$B?t(B}{\sum_{i}$B=PNOJ8(Bi$BCf$NA4(Bn-gram$B?t(B}$$ (28)

  
  

  $B$3$3$G!$<0(B(26)$B$N(BBP$B$O!$5!3#K]Lu$N=PNOJ8$,!$@52rJ8$h$j$bC;$$>l9g$N%Z%J%k%F%#$G$"$k!%(B $B$^$?!$(BBLEU$B$OJ8C10L$G$O$J$/%I%-%e%a%s%HC10L$G$N;HMQ$rA0Ds$H$7$F$$$k!%$=$N$?$a!$K\8&5f$G$O!$J8C10L$G(B $B;HMQ$9$k$?$a$KJQ99$,9T$o$l$F$$$k!%$D$^$j!$(B$P_{n}=1$$B$N>l9g$K(BBLEU$BCM$,(B0$B$K$J$C$F$7$^$&$?$a!$(B$P_{n}\neq0$$B$G$"$k$h$&$J(B $B:GBg$N(Bn$B$r(BN$B$H$7$F;HMQ$9$k!%(BBLEU$B$O(B0$B$+$i(B1$B$NCM$r=PNO$7!$%9%3%"$,Bg$-$$$[$II>2A$,NI$$!%$J$*!$K\8&5f$G$O!$(BBLEU$BCM$N(B$n$-gram$B$K(B4-gram$B$rMQ$$$F$$$k!%(B

• NIST[15]
  NIST$B$O!$(BBLEU$B$HF1MM$K(Bn-gram$B%^%C%AN($rMQ$$$?30)$B$K<($9>pJsNL$N7W;;<0$GF@$i$l$k>pJsNL$K$h$C$F=E$_IU$1$7$F$$$kE@$,0[$J$k!%$^$?!$%Z%J%k%F%#4X?t$b(BBLEU$B$N%Z%J%k%F%#4X?t$H0[$J$C$F$*$j!$(BNIST$B$NJ}$,J8D9(B $B$r9MN8$9$k$h$&$K%Z%J%k%F%#$,$D$1$i$l$k!%(BNIST$B$O!$(B0$B$+$i!g$NCM$r=PNO$7!$%9%3%"$,Bg$-$$$[$II>2A$,NI$$!%(B

  
  

  $$NIST = BP\sum_{n=1}^{N}\frac{\left({\displaystyle\sum_{$B=PNOJ8(Bi$B$H(B.. ...} Info_{i}\left(w_{i}\cdots w_{n}\right)\right)}{\sum_{i}$B%9%_%[%^%O%/(Bi$B%Fl&%[%A%((Bn-gram$B%=t}(B$$ (29)

  
  

  
  

  $$Info(w_{i}\cdots w_{i}) = \log_{2}\frac{$BI>2A%3!<%Q%9Cf$N(Bw_{1}\cdots w_{n-1}$B?t(B}{$BI>2A%3!<%Q%9Cf$N(Bw_{1}\cdots w_{n}$B?t(B}$$ (30)

  
  

• METEOR[16]
  METEOR$B$O!$:F8=N((BR$B$HE,9gN((BP$B$K4p$E$/(BF$BCM$KBP$7$FC18l$NHsO"B3@-$KBP$9$k%Z%J%k%F%#4X?t(B$Pen$$B$rMxMQ$7$?I>2A4p=`$G$"$k!%(B $B<0(B32$B$N%Z%J%k%F%#4X?t(B$Pen$$B$K$"$k(B$m$$B$O5!3#K]Lu$N=PNOJ8$H@52rJ8$H$N4V$G0lCW$7$?C18l?t$G$"$j!$(B$c$$B$O0lCW$7$?3FC18l$rBP>]$H$7$F8l=g$,F1$8$b$N$r(B1$B$D$N$^$H$^$j$H$7$FE}9g$7$?>l9g$N$^$H$^$j$N?t$G$"$k!%$7$?$,$C$F!$5!3#K]Lu$N=PNOJ8$H@52rJ8$,40A40lCW$N>l9g$K$O(B$c=1$$B$H$J$j!$8l=g$,A4$F5U$N>l9g$K$O(Bc=m$B$H$J$k!%(B$\alpha$$B!$(B$\beta$$B!$(B$\gamma$$B$NCM$O%Q%i%a!<%?$G$"$k!%(BMETEOR$B$O!$(B0$B$+$i(B1$B$NCM$r%9%3%"$H$7$F=PNO$7!$%9%3%"$,9b$$$[$II>2A$,NI$$!%(B

  
  

  $$F = \frac{P \times R}{\alpha \times P + \left(1 - \alpha \right) \times R}$$ (31)

  
  

  
  

  $$Pen = \gamma \times (c/m)^{\beta}$$ (32)

  
  

  
  

  $$METEOR = (1 - Pen) \times F$$ (33)

  
  

$B $B?M2A(B $B>e$X(B: $BI>2AJ}K!(B $BLa$k(B: $BI>2AJ}K!(B   $BL\