line spacing of Proof [closed]

I'm using the \linespread{1.8} for line spacing of my document in class offered by my university. Also, I'm using the \begin{proof} of the amsthm package. However, this \linespread{1.8} command is not applied to my proof. Then, how can I increase line spacing of my proof?

I attaches the mentioned codes in reply.

\documentclass[master,english,final]{kaist-ucs}
...
\usepackage{amsmath}
...
\begin{document}
...
\begin{proof}
...
\end{proof}...\end{document}

#### kaist-ucs.cls #####
\NeedsTeXFormat{LaTeX2e}[1995/12/01]
\ProvidesClass{kaist-ucs}%
[2008/10/21 v0.4 Standard KAIST Thesis document class, ko.TeX version]
\newif\if@isDoctor
\newif\if@isKorean
\newif\if@isFinal
\newif\if@PDFdoc\@PDFdocfalse
\newif\if@dvips\@dvipsfalse

\DeclareOption{doctor} {\@isDoctortrue}
\DeclareOption{master} {\@isDoctorfalse}
\DeclareOption{korean} {\@isKoreantrue}
\DeclareOption{english}{\@isKoreanfalse}
\DeclareOption{final}  {\@isFinaltrue}
\DeclareOption{draft}  {\@isFinalfalse}
\DeclareOption{pdfdoc} {\@PDFdoctrue}
\DeclareOption{dvips}  {\@dvipstrue}

\DeclareOption{leqno}  {\PassOptionsToClass{leqno}  {report}}
\DeclareOption{fleqn}  {\PassOptionsToClass{fleqn}  {report}}
\DeclareOption{openbib}{\PassOptionsToClass{openbib}{report}}

\ExecuteOptions{doctor,korean,final}
\ProcessOptions


Welcome to TeX.sx! Please add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – Stephan Lehmke Dec 8 '12 at 13:37
with the report class and only the amsthm package loaded, \linespread{1.8} is applied to the proof. so something else is at work here. as Stephan said, we need more information. – barbara beeton Dec 8 '12 at 13:52