minor updates (sec 16)

Chapter16/chapter16.tex

@@ -790,7 +790,7 @@ P(t|s)=\frac{\mathrm{cos}(s,t)/\tau}{\sum_{t'}\mathrm{cos}(s,t')\tau}
 \begin{figure}[h]
 \centering
 \includegraphics[scale=0.2,angle=90]{Chapter16/Figures/figure-unmt-idea2.jpg}
-\caption{无监督神经机器翻译思路2。}
+\caption{基于无监督词典归纳的方法}
 \label{fig:16-2}
 \end{figure}
 
@@ -805,7 +805,7 @@ P(t|s)=\frac{\mathrm{cos}(s,t)/\tau}{\sum_{t'}\mathrm{cos}(s,t')\tau}
 \begin{figure}[h]
 \centering
 \includegraphics[scale=0.2,angle=90]{Chapter16/Figures/figure-unmt-idea3.jpg}
-\caption{无监督神经机器翻译思路3。}
+\caption{模型初始化方法的优化}
 \label{fig:16-3}
 \end{figure}