\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)(10,6)
  \SpecialCoor

  \rput(1,1){\rnode{q_tm1}{$q_{t-1}$}}
  \rput(3,3){\rnode{q_t_tm1}{$q_{t|t-1}$}}
  \rput(5,5){\rnode{p_t}{$\hat{p}_t$}}
  \rput(5,1){\rnode{q_t}{$q_t$}}
  \rput(7,3){\rnode{q_tp1_t}{$q_{t+1|t}$}}
  \rput(9,5){\rnode{p_tp1}{$\hat{p}_{t+1}$}}
  \rput(9,1){\rnode{q_tp1}{$q_{t+1}$}}
  
  \psset{arrows=->,nodesep=3pt}
  \large
  \ncline{q_tm1}{q_t_tm1} \naput[nrot=:U]{\red Predict}
  \ncline{q_t_tm1}{p_t}   \naput[nrot=:U]{\red Update}
  \ncline{p_t}{q_t}       \nbput[nrot=:U]{\red Project}
  \ncline{q_t}{q_tp1_t}   \naput[nrot=:U]{\red Predict}
  \ncline{q_tp1_t}{p_tp1} \naput[nrot=:U]{\red Update}
  \ncline{p_tp1}{q_tp1}   \nbput[nrot=:U]{\red Project}
  
\end{pspicture}

\endTeXtoEPS
\end{document}