\documentclass{article}
\usepackage{com.braju.graphicalmodels}
\usepackage{amsmath}
% \special{papersize=40mm,80mm}
% \setlength{\pdfpagewidth}{40mm}
% \setlength{\pdfpageheight}{80mm}
% \usepackage[vcentering,dvips]{geometry}
% \geometry{papersize={80mm,120mm},total={80mm,120mm},margin=0mm}



\catcode`\@=11%

\pagestyle{empty}

\begin{document}
\TeXtoEPS

\LARGE
\psset{unit=10mm,arrowscale=1.5,linewidth=1.5pt}

\begin{pspicture}(0,0)(11,7)
  \SpecialCoor

  \rput(4,1){\GM@node[observed=true]{x_i}}
  \GM@label[angle=-90]{x_i}{$\boldsymbol{x}_i$}

  \rput(6,1){\GM@node[observed=true]{y_i}}
  \GM@label[angle=-90]{y_i}{$y_i$}
  
  \rput(5,3){\GM@node{z_i^s}}
  \GM@label[angle=90]{z_i^s}{$\boldsymbol{z}_i^s$}
  
  \rput(3,3){\GM@node{z_i^x}}
  \GM@label[angle=90]{z_i^x}{$\boldsymbol{z}_i^x$}

  \rput(7,3){\GM@node{z_i^y}}
  \GM@label[angle=90]{z_i^y}{$\boldsymbol{z}_i^y$}

  \rput(1,1){\GM@node{B_x}}
  \GM@label[angle=-90]{B_x}{$\boldsymbol{B}_x$}

  \rput(9,1){\GM@node{B_y}}
  \GM@label[angle=-90]{B_y}{$\boldsymbol{B}_y$}

  \rput(4,5){\GM@node{W_x}}
  \GM@label[angle=90]{W_x}{$\boldsymbol{W}_x$}

  \rput(6,5){\GM@node{W_y}}
  \GM@label[angle=90]{W_y}{$\boldsymbol{W}_y$}
  

  \rput(2.2,  0){\GM@plate{5.5}{4.2}{N}}
%  \rput(2.2,4.4){\GM@plate{5.5}{2}{L}}

  \ncline[arrows=->]{W_y}{y_i}
  \ncline[arrows=->]{W_x}{x_i}
  \ncline[arrows=->]{z_i^s}{y_i}
  \ncline[arrows=->]{z_i^y}{y_i}
  \ncline[arrows=->]{z_i^s}{x_i}
  \ncline[arrows=->]{z_i^x}{x_i}
  \ncline[arrows=->]{B_x}{x_i}
  \ncline[arrows=->]{B_y}{y_i}

\end{pspicture}

\endTeXtoEPS
\end{document}