bachelor-thesis/documentation/defense/defense.tex

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\AtBeginSection{\sectionpage}

\title{Inductive Short-Range Communication Channel}
\subtitle{Bachelorthesis}
\author[S. Kaderli]{Severin Kaderli}
\institute{Bern University of Applied Sciences}


\begin{document}

\maketitle

\section{Demo}


\section{Introduction}
\begin{frame}{Goals}
	The goal of the thesis was to create a communication channel that utilizes magnetic induction with the help of readily available components.
\end{frame}

\begin{frame}{Magnetic Induction}
	Magnetic Induction (MI), also known as magnetic flux density or simply the magnetic field,
    is a physical quantity measured in Tesla T. The movement of electric charges in a conductor produces a magnetic field around the conductor. 
\end{frame}

\section{Solution}
\begin{frame}{MagSend}
	\begin{itemize}
        \item{Uses two devices}
        \item{A laptop as sender}
        \item{A phone as receiver}
        \item{Laptop modifies a magnetic field}
        \item{The phone measures the field}
    \end{itemize}
\end{frame}

\begin{frame}{Calibration}
    \begin{columns}
        \begin{column}{.5\linewidth}
            \begin{figure}
                \fbox{\includegraphics[width=1\linewidth]{test_cases/t2.png}}
            \end{figure}
        \end{column}
        \begin{column}{.5\linewidth}
            \begin{figure}
                \fbox{\includegraphics[width=0.45\linewidth]{test_cases/t5.jpg}}
            \end{figure}
        \end{column}
    \end{columns}
\end{frame}

\begin{frame}{Calibration}
    \framesubtitle{CPU Load}
    \begin{figure}
        \fbox{\includegraphics[width=0.85\linewidth]{test_cases/t2_2.png}}
    \end{figure}
\end{frame}

\begin{frame}{Sending}
	\begin{figure}
        \fbox{\includegraphics[width=0.65\linewidth]{test_cases/t9.png}}
    \end{figure}
\end{frame}

\begin{frame}{Packet Format}
	\begin{itemize}
        \item{Header}
            \begin{itemize}
                \item{4 Bit}
                \item{Payload Length; Up to 16 bytes}
            \end{itemize}
        \item{Payload}
            \begin{itemize}
                \item{Bit stream of the ASCII Text}
                \item{Up to 16 characters}
            \end{itemize}
        \item{Checksum}
            \begin{itemize}
                \item{CRC-8-AUTOSAR}
            \end{itemize}
    \end{itemize}
\end{frame}

\begin{frame}{Packet Format}
    \framesubtitle{CRC-8-AUTOSAR}
	\begin{itemize}
        \item{Created by AUTOSAR}
        \item{Single, and double bit errors}
        \item{Burst errors of up to 8-bits}
        \item{Errors with an odd number of bits}
        \item{Up to 4 single bit errors in a message length up to 119 bits}
    \end{itemize}
\end{frame}

\begin{frame}{Packet Format}
    \framesubtitle{Structure}
	\begin{figure}
        \includegraphics[width=1\linewidth]{packet.png}
    \end{figure}
\end{frame}

\begin{frame}{Packet Format}
    \framesubtitle{Example for Text: "Test"}
	\begin{figure}
        \includegraphics[width=1\linewidth]{packet_test.png}
    \end{figure}
\end{frame}

\begin{frame}{Transmission}
	\begin{itemize}
        \item{Depending on the text, the website puts load on the CPU in a controlled way}
        \item{High signals are 1, and low signals are 0}
        \item{Packet is encoded using manchester encoding}
        \item{Preamble to indicate the start of a packet}
    \end{itemize}
\end{frame}

\begin{frame}{Transmission}
    \framesubtitle{Encoding}
	\begin{figure}
        \includegraphics[width=0.8\linewidth]{manchester_code.png}
    \end{figure}
    \footnote{https://commons.wikimedia.org/wiki/File:Manchester\_encoding\_both\_conventions.svg}
\end{frame}

\begin{frame}{Transmission}
    \framesubtitle{CPU Load}
	\begin{figure}
        \includegraphics[width=0.9\linewidth]{test_cases/t3_2.png}
    \end{figure}
\end{frame}

\begin{frame}{Transmission}
    \framesubtitle{CPU Load Example for Packet}
	\begin{figure}
        \includegraphics[width=0.9\linewidth]{cpu_test.png}
    \end{figure}
\end{frame}

\begin{frame}{Reception}
	The phone uses a magnetometer sensor to get the signal from the magnetic field. From that signals it deconstructs the packet to get to the text.
\end{frame}

\begin{frame}{Reception}
    \framesubtitle{Sensor Data}
	\begin{figure}
        \includegraphics[width=0.8\linewidth]{magnetic_induction_cpu.png}
    \end{figure}
\end{frame}

\begin{frame}{Reception}
    \framesubtitle{Sensor Data for Packet}
	\begin{figure}
        \includegraphics[width=0.9\linewidth]{magnetic_induction_test_packet.png}
    \end{figure}
\end{frame}

\begin{frame}{Benchmarking}
    \begin{itemize}
        \item{Works well at idle CPU load with 1 bit/s}
        \item{Problems already with 25\% CPU load}
        \item{Problems with thermal throttling}
    \end{itemize}
\end{frame}

\begin{frame}{Benchmarking}
    \framesubtitle{Thermal Throttling}
	\begin{figure}
        \includegraphics[width=0.9\linewidth]{benchmarking/1bps_25.png}
    \end{figure}
\end{frame}

\begin{frame}{Use Cases}
	\begin{itemize}
        \item{Works without connectivity e.g. in airplane mode}
        \item{Works better under water than radio waves}
        \item{Possible applications for small data transmissions: similar to QR codes, 2FA}
    \end{itemize}
\end{frame}

\begin{frame}{Future Work}
	\begin{itemize}
        \item{Enhance the robustness}
        \item{Increase transfer speed}
        \item{Improve user experience and user interface}
    \end{itemize}
\end{frame}

\section{Project Management}
\begin{frame}{Organization}
    \begin{itemize}
        \item{Git Repository}
        \item{Weekly meetings with advisor}
        \item{Created plan at the start}
    \end{itemize}
\end{frame}

\begin{frame}{Project Plan}
    \begin{figure}
        \includegraphics[width=0.7\linewidth]{project_plan.png}
    \end{figure}
\end{frame}

\begin{frame}{Project Plan}
    \framesubtitle{Actual Plan}
    \begin{figure}
        \includegraphics[width=0.7\linewidth]{actual_plan.png}
    \end{figure}
\end{frame}

\begin{frame}{Project Plan}
    \framesubtitle{Explanation}
    \begin{itemize}
        \item{Beginning went well}
        \item{COVID-19}
        \item{Winter break}
    \end{itemize}
\end{frame}

\begin{frame}{Conclusion}
    \begin{itemize}
        \item{Working prototype}
        \item{Better planning}
        \item{Better logging}
    \end{itemize}
\end{frame}

\begin{frame}{Try It Yourself}
    \begin{columns}
        \begin{column}{.5\linewidth}
            https://magsend.kaderli.dev
        \end{column}
        \begin{column}{.5\linewidth}
            \begin{figure}
                \includegraphics[width=0.9\linewidth]{qr_app.png}
            \end{figure}
        \end{column}
    \end{columns}
\end{frame}

\section{Questions}


\end{document}