1) Use the prosper package. seminar.sty is for old people.
2) Download mpa scheme from here: http://www.nefkom.net/georg.drenkhahn/prosper/PPRmpa.sty
3) Download logo from here: http://nlp.stanford.edu/local/nlp-logos/nlp-logo.eps
4) Start your declaration like this:

\documentclass[pdf,mpa]{prosper}
%\usepackage{graphicx}
%\usepackage{amsfonts}
 
\title{}
\subtitle{}
\author{}
\email{}
\institution{Stanford NLP Group}
\Logo{\includegraphics[height=.6in]{nlp-logo}}
 
\begin{document}
\maketitle
 
Complete example here: http://nlp.stanford.edu/local/nlp-latex/sigtest-example/