投影仪幻灯片中的不透明度徽标

Question

你好，我有以下 Beamer 幻灯片，我想让右下角的徽标的不透明度达到 50% 吗？

这是我的代码

    \documentclass[a4paper, ]{beamer}
    \usepackage[danish]{babel}
    \usepackage[utf8]{inputenc}
    \renewcommand{\danishhyphenmins}{22}
    \usepackage[T1]{fontenc}

\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{tikz}
\usepackage{pgfplots}
\usepackage{appendixnumberbeamer}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{units}

\usepackage{algpseudocode}
\usepackage[]{algorithm}
\algnewcommand\algorithmicinitialize{\textbf{\: \ initialization:}}
\algnewcommand\Initialize{\item[\algorithmicinitialize]}
\renewcommand{\algorithmicrequire}{\textbf{input:}}
\renewcommand{\algorithmicensure}{\textbf{output:}}

\usetheme{Madrid}
\usecolortheme{dolphin}

\title[Dept. of Theoretical Statistics]{Particle Filtering for Sequential Markov Coalescent}
\author[Simon Schou Simonsen]{Simon Schou Simonsen}
\institute[]{\textit{In collaboration with: }\\\textit{Svend V. Nielsen and Asger Hobolth}}
\date{26. januar 2015}
\logo{\includegraphics[scale=0.65]{segl.pdf}}

\begin{document}

\frame{\titlepage}

\begin{frame}
\frametitle{Program}
\tableofcontents
\end{frame}



\end{document}