\subsection{Write Math}

\begin{frame}{write-math.com}
    \begin{itemize}
        \item a website where users can add labeled training data
        \item works with desktop computers and touch devices
        \item symbol recognition can be done by multiple classifiers
        \item users can contribute formulas
        \item users can vote for formulas
        \item user who wrote the formula can accept one formula
    \end{itemize}
\end{frame}

\framedgraphic{Classify}{../images/classify.png}
\framedgraphic{Workflow}{../images/workflow.png}
\framedgraphic{User page}{../images/user-page.png}
\framedgraphic{Information about handwritten-data}{../images/view.png}
\framedgraphic{Non-mathematical symbols}{../images/yinyang.png}
\framedgraphic{Training}{../images/train.png}
\framedgraphic{Ranking}{../images/ranking.png}
\framedgraphic{Symbol page}{../images/symbol.png}

\begin{frame}{Statistics}
    \begin{itemize}
        \item 40 users
        \item 1076 symbols
        \item 5519 handwritten symbols (e.g. 195 times the letter \enquote{A})
        \begin{itemize}
            \item only 264 have 4 lines
            \item only 36 have 5 lines
            \item only 16 have 6 lines
            \item only 19 have 7 lines or more
            \item none has more than 12 lines
        \end{itemize}
    \end{itemize}
\end{frame}

\begin{frame}{First classification worker}
    \begin{itemize}
        \item preprocessing: Scale to fit into unit square while keeping the aspect
              ratio
        \item applies dynamic time warping
        \item compares a new handwritten symbol with every handwritten symbol
              in the database
        \item[$\Rightarrow$] Classification time is in $\mathcal{O}(\text{handwritten symbols})$,
              but we rather would like $\mathcal{O}(\text{symbols})$
        \item the current server / workflow can only handle about 4000 handwritten
              symbols
        \item[$\Rightarrow$] Another way to classify is necessary
    \end{itemize}
\end{frame}