\node[anchor=north west] (original4-3) at ([yshift=0.3em]original4-2.south west) {\scriptsize{悲哀，让我跟你去吧！''``哦，……爱，我实在太悲哀了，想自己一个人呆一会儿！''悲哀答}};
\node[anchor=north west] (original4-4) at ([yshift=0.3em]original4-3.south west) {\scriptsize{道。快乐走近爱的身边，但是她太快乐了，竟然没有听见爱在叫她！}};
%机器翻译--------------
\node [anchor=north west] (mt4) at ([xshift=-3.5em,yshift=-0.3em]original4-4.south west) {\scriptsize{机器翻译：At this time, Richness {\color{red}\underline{passed by}} in a big ship. Love said, ``Rich, can you take me away?'' Richness}};
\node [anchor=north west] (mt4-1) at ([xshift=3.5em,yshift=0.4em]mt4.south west) {\scriptsize{replied, ``No, {\color{red}\underline{there are many treasures}} of gold and silver in my ship,and there is no place for you.''}};
\node [anchor=north west] (mt4-2) at ([xshift=0em,yshift=0.3em]mt4-1.south west) {\scriptsize{ Love saw vanity in a magnificent boat and said, ``Vanity, help me!'' ``I can't help you. You are {\color{red}\underline{soak}}}};
\node [anchor=north west] (mt4-3) at ([yshift=0.4em]mt4-2.south west) {\scriptsize{{\color{red}\underline{-ed to the skin}} and will damage my beautiful boat.'' When sorrow came, love asked him for help: ``}};
\node [anchor=north west] (mt4-4) at ([yshift=0.4em]mt4-3.south west) {\scriptsize{sorrow, let me go with you!'' ``Oh,...love, I am so sad that I want to be alone for a while!'' Sadly rep}};
\node [anchor=north west] (mt4-5) at ([yshift=0.4em]mt4-4.south west) {\scriptsize{-lied. Happiness {\color{red}\underline{approached}} love, but she was too happy to hear love calling her!}};
%人工翻译---------------
\node [anchor=north west] (ht4) at ([xshift=-3.5em,yshift=0.3em]mt4-5.south west) {\scriptsize{人工翻译：At that moment, WEALTH {\color{red}\underline{was passing by}} in a big boat. Love said,``WEALTH, can you take me}};
\node [anchor=north west] (ht4-1) at ([xshift=3.5em,yshift=0.4em]ht4.south west) {\scriptsize{with you?'' WEALTH answered, ``no, {\color{red}\underline{there is a lot}} of gold and silver in my boat. There is no place}};
\node [anchor=north west] (ht4-2) at ([yshift=0.4em]ht4-1.south west) {\scriptsize{for you.'' Love saw VANITY in a beautiful boat and said, ``VANITY, help me!'' ``I can't help you.}};
\node [pos=0.4,left,xshift=-0.4em,yshift=2.0em] (mt4) {\scriptsize{机器翻译：At this time, Richness {\color{red}\underline{passed by}} in a big ship. Love said, ``Rich, can you take me away?'' Richness}};
\node [anchor=north west] (mt4-1) at ([xshift=3.5em,yshift=0.4em]mt4.south west) {\scriptsize{replied, ``No, {\color{red}\underline{there are many treasures}} of gold and silver in my ship,and there is no place for you.''}};
\node [anchor=north west] (mt4-2) at ([xshift=0em,yshift=0.3em]mt4-1.south west) {\scriptsize{ Love saw vanity in a magnificent boat and said, ``Vanity, help me!'' ``I can't help you. You are {\color{red}\underline{soak}}}};
\node [anchor=north west] (mt4-3) at ([yshift=0.4em]mt4-2.south west) {\scriptsize{{\color{red}\underline{-ed to the skin}} and will damage my beautiful boat.'' When sorrow came, love asked him for help: ``}};
\node [anchor=north west] (mt4-4) at ([yshift=0.4em]mt4-3.south west) {\scriptsize{sorrow, let me go with you!'' ``Oh,...love, I am so sad that I want to be alone for a while!'' Sadly rep}};
\node [anchor=north west] (mt4-5) at ([yshift=0.4em]mt4-4.south west) {\scriptsize{-lied. Happiness {\color{red}\underline{approached}} love, but she was too happy to hear love calling her!}};
%人工翻译---------------
\node [anchor=north west] (ht4) at ([xshift=-3.5em,yshift=0.3em]mt4-5.south west) {\scriptsize{人工翻译：At that moment, WEALTH {\color{red}\underline{was passing by}} in a big boat. Love said,``WEALTH, can you take me}};
\node [anchor=north west] (ht4-1) at ([xshift=3.5em,yshift=0.4em]ht4.south west) {\scriptsize{with you?'' WEALTH answered, ``no, {\color{red}\underline{there is a lot}} of gold and silver in my boat. There is no place}};
\node [anchor=north west] (ht4-2) at ([yshift=0.4em]ht4-1.south west) {\scriptsize{for you.'' Love saw VANITY in a beautiful boat and said, ``VANITY, help me!'' ``I can't help you.}};
\node [anchor=north west] (ht4-3) at ([yshift=0.4em]ht4-2.south west) {\scriptsize{You are {\color{red}\underline{all wet,}} and will break my pretty boat.'' Then SADNESS came. Love asked for help,``SAD}};
\node [pos=0.4,left,xshift=-0.4em,yshift=2.0em,opacity=0] (mt4) {\scriptsize{机器翻译：At this time, Richness {\color{red}\underline{passed by}} in a big ship. Love said, ``Rich, can you take me away?'' Richness}};
\node [anchor=north west] (ht4-3) at ([xshift=3.5em,yshift=1.3em]mt4.south west) {\scriptsize{You are {\color{red}\underline{all wet,}} and will break my pretty boat.'' Then SADNESS came. Love asked for help,``SAD}};
\node [anchor=north west] (ht4-4) at ([yshift=0.4em]ht4-3.south west) {\scriptsize{-NESS, let me go with you!'' ``Oh,...LOVE, I am so sad that I want to be alone for a while!'' ``Repli}};
\node [anchor=north west] (ht4-5) at ([yshift=0.4em]ht4-4.south west) {\scriptsize{-ed SADNESS. JOY {\color{red}\underline{came close to }} love, but she was so happy that she did not hear him call her!}};
\parinterval通常一个典型的{\small\bfnew{基于转换规则的机器翻译}}\index{基于转换规则的机器翻译}(Transfer Based Translation)过程可以被视为``独立分析-独立生成-相关转换''的过程\cite{jurafsky2000speech}。如图\ref{fig:1-11}所示，整个完整的机器翻译过程可以分成六个步骤，其中每一个步骤都是通过相应的翻译规则来完成，比如第一个步骤中需要构建源语词法分析规则，第二个步骤中需要构建源语句法分析规则，第三个和第四个步骤中需要构建源语-目标语词汇和结构转换规则等等。
\parinterval 基于转换的方法可以通过词汇层、句法层和语义层完成源语和目标的转换过程，虽然采用了独立分析和独立生成的两个子过程，但中间包含一个从源语到目标语的相关转换过程。这就会导致一个实际问题，假设需要实现$N$个语言之间互译的机器翻译系统，采用基于转换的方法，需要构建$N(N-1)$个不同的机器翻译系统，这个构建代价是非常高的。为了解决这个问题，一种有效的解决方案是使用{\small\bfnew{基于中间语言的机器翻译}}\index{基于中间语言的机器翻译}(Interlingua Based Translation)方法。
\item OpenSeq2Seq。由NVIDIA团队开发的\cite{DBLP:journals/corr/abs-1805-10387}基于TensorFlow的模块化架构，用于序列到序列的模型，允许从可用组件中组装新模型，支持混合精度训练，利用NVIDIA Volta Turing GPU中的Tensor核心，基于Horovod的快速分布式训练，支持多GPU，多节点多模式。网址：\url{https://nvidia.github.io/OpenSeq2Seq/html/index.html}
\parinterval机器翻译相关评测主要有两种组织形式，一种是由政府及国家相关机构组织，权威性强。如由美国国家标准技术研究所组织的NIST评测、日本国家科学咨询系统中心主办的NACSIS Test Collections for IR（NTCIR）PatentMT、日本科学振兴机构（Japan Science and Technology Agency，简称JST）等组织联合举办的Workshop on Asian Translation（WAT）以及国内由中文信息学会主办的全国机器翻译大会（China Conference on Machine Translation，简称CCMT）；另一种是由相关学术机构组织，具有领域针对性的特点，如倾向新闻领域的Conference on Machine Translation（WMT）以及面向口语的International Workshop on Spoken Language Translation（IWSLT）。下面将针对上述评测进行简要介绍。
\item WMT由Special Interest Group for Machine Translation（SIGMT）主办，会议自2006年起每年召开一次，是一个涉及机器翻译多种任务的综合性会议，包括多领域翻译评测任务、质量评价任务以及其他与机器翻译的相关任务（如文档对齐评测等）。现在WMT已经成为机器翻译领域的旗舰评测会议，很多研究工作都以WMT评测结果作为基准。WMT评测涉及的语言范围较广，包括英语、德语、芬兰语、捷克语、罗马尼亚语等十多种语言，翻译方向一般以英语为核心，探索英语与其他语言之间的翻译性能，领域包括新闻、信息技术、生物医学。最近，也增加了无指导机器翻译等热门问题。WMT在评价方面类似于CCMT，也采用人工评价与自动评价相结合的方式，自动评价的指标一般为BLEU、TER 等。此外，WMT公开了所有评测数据，因此也经常被机器翻译相关人员所使用。更多WMT的机器翻译评测相关信息可参考SIGMT官网：\url{http://www.sigmt.org/}。
\parinterval 以上评测数据大多可以从评测网站上下载，此外部分数据也可以从LDC（Lingu-istic Data Consortium）上申请，网址为\url{https://www.ldc.upenn.edu/}。ELRA（Euro-pean Language Resources Association）上也有一些免费的语料库供研究使用，其官网为\url{http://www.elra.info/}。更多机器翻译的语料信息可参看附录\ref{appendix-A}。
