\documentclass{article}
\usepackage{com.braju.graphicalmodels}

\catcode`\@=11%

\pagestyle{empty}

\begin{document}
\TeXtoEPS

\LARGE
\psset{unit=10mm,arrowscale=1.5,linewidth=1.5pt}
\begin{pspicture}(0,0)(8,1)%\showgrid
  \SpecialCoor

  \rput(1,1){\GM@node[observed=true]{x1}} \GM@label[angle=-90]{x1}{$x_{1}$}
  \rput(3,1){\GM@node[observed=true]{x2}} \GM@label[angle=-90]{x2}{$x_{2}$}
  \rput(5,1){\GM@node[observed=true]{x3}} \GM@label[angle=-90]{x3}{$x_{3}$}
  \rput(7,1){\GM@node[observed=true]{x4}} \GM@label[angle=-90]{x4}{$x_{4}$}
  \rput(9,1){\rnode{x5}{\psframebox[linecolor=white]{$\cdots$}}}

  \ncarc[arcangle=45,arrows=->]{x1}{x3}
  \ncline[arrows=->]{x1}{x2}

  \ncline[arrows=->]{x2}{x3}
  \ncarc[arcangle=45,arrows=->]{x2}{x4}
  \ncline[arrows=->]{x3}{x4}

  \ncline[arrows=->]{x4}{x5}
\end{pspicture}

\endTeXtoEPS
\end{document}