\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,-1)(6,6)
  \SpecialCoor

  \rput(1,0){\GM@node[observed=true]{x_t1}}
  \GM@label[angle=-90]{x_t1}{$\boldsymbol{x}_{t-1}$}

  \rput(4,0){\GM@node[observed=true]{x_t}}
  \GM@label[angle=-90]{x_t}{$\boldsymbol{x}_t$}

  \rput(2,1.5){\GM@node[observed=true]{y_t1}}
  \GM@label[angle=-90]{y_t1}{$\boldsymbol{y}_{t-1}$}

  \rput(5,1.5){\GM@node[observed=true]{y_t}}
  \GM@label[angle=-90]{y_t}{$\boldsymbol{y}_t$}

  \rput(1,3){\GM@node{s_t1}}
  \GM@label[angle=140]{s_t1}{$s_{t-1}$}
  
  \rput(4,3){\GM@node{s_t}}
  \GM@label[angle=140]{s_t}{$s_t$}

  \rput(1,5){\GM@node{theta_t1}}
  \GM@label[angle=90]{theta_t1}{$\boldsymbol{\theta}_{t-1}$}

  \rput(4,5){\GM@node{theta_t}}
  \GM@label[angle=90]{theta_t}{$\boldsymbol{\theta}_t$}

  \ncline{->}{theta_t1}{theta_t}
  \ncline{->}{x_t1}{s_t1}
  \ncline{->}{x_t}{s_t}
  \ncline{->}{s_t1}{y_t1}
  \ncline{->}{s_t}{y_t}
  \ncline{->}{theta_t1}{s_t1}
  \ncline{->}{theta_t}{s_t}

\end{pspicture}

\endTeXtoEPS
\end{document}
