update: after presentation

chap2/literature_review.tex

@@ -257,22 +257,23 @@ According to Flesch, the values retrieved by applying the formula to text can be
 classified according to the ranges given in Table \ref{tbl:fre_ranges} \cite{flesch_fre}.
 \begin{table}
   \centering
-  \caption{Categories for different FRE scores to classify the understandability
+  \ra{1.3}
-    of text \cite{flesch_fre}}
+  \begin{tabular}{?l^c}
-  \label{tbl:fre_ranges}
+    \toprule
-  \begin{tabular}{l|c}
+    \multicolumn{1}{c}{\emph{FRE}}& \emph{Understandability}  \\
-    \hline\hline
+    \midrule
-    \multicolumn{1}{c|}{FRE}      & Understandability  \\
+    \multicolumn{1}{c}{0 - 30}    & Very difficult     \\
-    \hline
-    \multicolumn{1}{c|}{0 - 30}   & Very difficult     \\
     30 - 50                       & Difficult          \\
     50 - 60                       & Fairly difficult   \\
     60 - 70                       & Standard           \\
     70 - 80                       & Fairly easy        \\
     80 - 90                       & Easy               \\
-    \multicolumn{1}{r|}{90 - 100} & Very easy          \\
+    \multicolumn{1}{r}{90 - 100}  & Very easy          \\
-    \hline
+    \bottomrule
   \end{tabular}
+  \caption{Categories for different FRE scores to classify the understandability
+    of text \cite{flesch_fre}}
+  \label{tbl:fre_ranges}
 \end{table}
 
 \subsubsection{Performance Metrics}

chap3/implementation.tex

@@ -21,9 +21,8 @@ and measure the applied force by the finger usually responsible to actuate a
 specific key.
 
 Both implementations are explained in more detail in the following two sections.
-\label{sec:label}
 \subsection{Typing Test Platform}
-\label{sec:label}
+\label{sec:gott}
 The platform we created is called \gls{GoTT} because the backend, which is the
 server side code, is programmend in Go, a programming language developed by a
 team at Google \cite{golang}. The decision for Go was made, because Go's
@@ -154,7 +153,10 @@ test or after every keyboard respectively. To manually match all finished
 questionnaires to the corresponding typing tests and keyboards, could introduce
 an unwanted source of errors. Therefore, we implemented a survey tool into
 \gls{GoTT} which automatically matched completed questionnaires to typing tests
-and keyboards. All questionnaires can be observed in Appendix \ref{app:gott}.
+and keyboards. The \gls{PTTQ} resembled the \gls{KCQ} \cite[56]{iso9241-411} and
+the questions for the \gls{PKQ} were gathered from the \gls{UEQ-S}
+\cite{schrepp_ueq_handbook}. All questionnaires can be observed in Appendix
+\ref{app:gott}.
 
 \item \textbf{The text crowdsourcing platform} was required because of the
 potential introduction of observer bias as described in Section
@@ -204,7 +206,10 @@ were used to derive the regex patterns to identify syllables
 with the help of multiple unit tests and also compared to scores obtained by
 another website \footnote{\url{https://fleschindex.de/berechnen/}} offering the
 calculation for German texts. The \gls{UI} for the crowdsourcing page is shown
-in Appendix \ref{app:gott}.
+in Appendix \ref{app:gott}. The gathered text snippets were, first checked for
+typos using \textit{Duden Mentor}\footnote{\url{https://mentor.duden.de/}},
+then randomized and finally aggregated into equally long texts with nearly
+identical \gls{FRE} scores (mean = 80.10, SD = 0.48).
 
 \begin{listing}[H]
 \caption{Algorithm that calculates the \gls{FRE} score for a given string in German

chap4/methodology.tex

@@ -24,6 +24,7 @@ including our adjusted keyboard, to values obtained with the participant's own
 keyboards.
 
 \subsection{Preliminary telephone interview}
+\label{sec:telephone_interview}
 Some of the studies we found that researched implications of actuation force on
 speed, preference or other metrics were published between 1984 and 2010. That is
 why we wanted to ascertain if and how, with the advance of technology in recent
@@ -84,7 +85,7 @@ actuation force is 35 g ($\approx$ 0.34 \gls{N}) the most common one is 50 g
 
 \begin{figure}[ht]
   \centering
-  \includegraphics[width=0.8\textwidth]{images/keyswitches_brands}
+  \includegraphics[width=0.9\textwidth]{images/keyswitches_brands}
   \caption{Available actuation forces for keyswitches of major keyswitch manufacturers}
   \label{fig:keyswitches_brands}
 \end{figure}
@@ -133,9 +134,9 @@ and \textit{Z} can be observed in Figure \ref{fig:FM_example}.
 The results of the measurements are given in Table \ref{tbl:finger_force}. The
 median of the means (15.47 N) of all measurements was used to calculate the
 actuation forces in gram for the keyswitches later incorporated in the layout
-for adjusted keyboard. We used Eq. (\ref{eq:N_to_g}) and
+for the adjusted keyboard. We used Eq. (\ref{eq:N_to_g}) and
-Eq. (\ref{eg:actuation_forces}) to calculate the gram values for each measured
+Eq. (\ref{eq:actuation_forces}) to calculate the theoretical gram values for
-keyswitch.
+each measured keyswitch.
 
 \begin{equation}
   \label{eq:N_to_g}
@@ -161,45 +162,395 @@ key can be seen in Eq. (\ref{eq:force_example}).
   AF_{P} = GFR * MAF_{P} = 3.23 \frac{g}{N} * 10.45 N \approx 33.75 g
 \end{equation}
 
-Because there are only certain spring
+We then assigned the each theoretical actuation force to a group that resembles
+a spring resistance which is available on the market or can be adjusted to that
+value. We matched the results from Table \ref{tbl:finger_force} to the groups
+representing the best fit shown in Table \ref{tbl:force_groups}.
+
 
 % Custom spring stiffness
 % https://www.engineersedge.com/spring_comp_calc_k.htm
+% https://www.eng-tips.com/viewthread.cfm?qid=198360
 
 
-\begin{table*}[]
+\begin{table}
   \centering
   \ra{1.3}
-  \begin{tabularx}{13cm}{?l^l^l^l^l^l^l^l}
+  \begin{tabular}{?l^l^l^l^l^l^l^l^l^l^l}
     \toprule
-    \multicolumn{8}{c}{\textbf{Bottom Row}}\\
+    \textbf{Bottom Row} & \multicolumn{2}{c}{\emph{F5}} & \phantom{.} & \multicolumn{1}{c}{\emph{F4}} & \phantom{.} & \multicolumn{1}{c}{\emph{F3}} &  \phantom{.} &\multicolumn{3}{c}{\emph{F2}}\\
+    \cmidrule{2-3}\cmidrule{5-5}\cmidrule{7-7}\cmidrule{9-11}
     \rowstyle{\itshape}
-    \emph{Key}                 & ↑     & -     & :     & ;     & M     & N     & B    \\
+    Key                        & ↑     & -     && :     && ;     && M     & N     & B    \\
     \midrule
-    \emph{Mean Force (N)}      & 11.23 & 10.84 & 14.22 & 15.34 & 16.38 & 15.6  & 14.36\\
+    \emph{Mean Force (N)}      & 11.23 & 10.84 && 14.22 && 15.34 && 16.38 & 15.60 & 14.36\\
-    \emph{Actuation Force (g)} & 36.05 & 34.8  & 45.65 & 49.24 & 52.58 & 50.08 & 46.1\\
+    \emph{Actuation Force (g)} & 36.27 & 35.01 && 45.93 && 49.55 && 52.91 & 50.39 & 46.38\\
-  \end{tabularx}
+  \end{tabular}
-  \begin{tabularx}{13cm}{?l^l^l^l^l^l^l^X}
+  \begin{tabular}{?l^l^l^l^l^l^l^l^l^l^l}
-    \multicolumn{8}{c}{\textbf{Home Row}}\\
+    \\
+    \textbf{Home Row} & \multicolumn{2}{c}{\emph{F5}} & \phantom{.} & \multicolumn{1}{c}{\emph{F4}} & \phantom{.} & \multicolumn{1}{c}{\emph{F3}} &  \phantom{.} &\multicolumn{2}{c}{\emph{F2}}\\
+    \cmidrule{2-3}\cmidrule{5-5}\cmidrule{7-7}\cmidrule{9-10}
     \rowstyle{\itshape}
-    \emph{Key}                 & Ä     & Ö     & L     & K     & J     & H     &\\
+    Key                        & Ä     & Ö     && L     && K     && J     & H     &\\
     \midrule
-    \emph{Mean Force (N)}      & 11.88 & 12.27 & 15.84 & 18.56 & 17.78 & 18.43 &\\
+    \emph{Mean Force (N)}      & 11.88 & 12.27 && 15.84 && 18.56 && 17.78 & 18.43 & \phantom{69.69}\\
-    \emph{Actuation Force (g)} & 38.13 & 39.39 & 50.85 & 59.58 & 57.07 & 59.16 &\\
+    \emph{Actuation Force (g)} & 38.37 & 39.63 && 51.16 && 59.95 && 57.43 & 59.53 &\\
-  \end{tabularx}
+  \end{tabular}
-  \begin{tabularx}{13cm}{?l^l^l^l^l^l^l^l}
+  \begin{tabular}{?l^l^l^l^l^l^l^l^l^l^l}
-    \multicolumn{8}{c}{\textbf{Top Row}}\\
+    \\
+    \textbf{Top Row} & \multicolumn{3}{c}{\emph{F5}} & \phantom{.} & \multicolumn{1}{c}{\emph{F4}} & \phantom{.} & \multicolumn{1}{c}{\emph{F3}} &  \phantom{.} &\multicolumn{2}{c}{\emph{F2}}\\
+    \cmidrule{2-4}\cmidrule{6-6}\cmidrule{8-8}\cmidrule{10-11}
     \rowstyle{\itshape}
-    \emph{Key}                 & +     & Ü     & P     & O     & I     & U     & Z    \\
+    Key                        & +     & Ü     & P     && O     && I     && U     & Z    \\
     \midrule
-    \emph{Mean Force (N)}      & 10.8  & 10.7  & 10.45 & 14.34 & 17.95 & 17.0  & 16.8 \\
+    \emph{Mean Force (N)}      & 10.80 & 10.70 & 10.45 && 14.34 && 17.95 && 17.00 & 16.80 \\
-    \emph{Actuation Force (g)} & 34.67 & 34.35 & 33.54 & 46.03 & 57.62 & 54.57 & 53.93\\
+    \emph{Actuation Force (g)} & 34.88 & 34.56 & 33.75 && 46.32 && 57.98 && 54.91 & 54.26\\
     \bottomrule
-  \end{tabularx}
+  \end{tabular}
   \caption{Maximum force measurements for all digits of the right hand in
     different positions. The mean force of six participants is shown in the
     first row of each table and the resulting actuation force for the
     corresponding keyswitch in the following row. The columns indicate the label
     of the scale on the measuring device which can be seen in Figure
-    \ref{fig:FM_example}. \textit{↑} stands for the shift key.}
+    \ref{fig:FM_example}. \textit{↑} stands for the shift key. \textit{F5} :=
-\end{table*}
+    little finger, ..., \textit{F2} := index finger}
+  \label{tbl:finger_force}
+\end{table}
+
+\begin{table}
+  \centering
+  \ra{1.3}
+  \begin{tabular}{?l^c^c^c^c^c^c^c}
+    \toprule
+    \rowstyle{\itshape}
+    \textbf{Spring Stiffness:} &              35 g & 40 g  & 45 g  & 50 g  & 55 g  & 60 g \\
+    \midrule
+    \emph{\textbf{F5:} Key (g)} & \centered{P&(33.75)\\Ü&(34.56)\\+&(34.56)\\-&(35.01)\\↑&(36.27)}& \centered{Ä&(38.37)\\Ö&(39.63)}&&&&&\\
+    \midrule
+    \emph{\textbf{F4:} Key (g)} &&& \centered{:&(45.93)\\O&(46.32)} &\centered{L&(51.16)}&&\\
+    \midrule
+    \emph{\textbf{F3:} Key (g)} &&&&\centered{;&(49.55)}&&\centered{I&(57.98)\\K&(59.95)}\\
+    \midrule
+    \emph{\textbf{F2:} Key (g)} &&&\centered{B&(46.38)}&\centered{N&(50.39)\\M&(52.91)}&\centered{Z&(54.26)\\U&(54.91)\\J&(57.43)}&\centered{H&(59.53)}\\
+    \bottomrule
+  \end{tabular}
+  \caption{Categorization of theoretical actuation forces acquired with
+    Eq. (\ref{eq:actuation_forces}), into groups of more commonly available
+    stiffnesses of springs. The rows indicate which finger is used to press the
+    key. \textit{F5} := little finger, ..., \textit{F2} := index finger}
+  \label{tbl:force_groups}
+\end{table}
+
+We simply mirrored the results of the right hand, for keys operated by the left
+hand and copied the values to keys which are out of reach without lifting the
+hand. Finally, we created the adjusted keyboard layout that can be examined in
+Figure \ref{fig:adjusted_layout}. This layout was used in our main experiment
+where we compared it to four different keyboards with uniform actuation forces
+which is discussed in more detail in the following section.
+
+\begin{figure}[ht]
+  \centering
+  \includegraphics[width=1.0\textwidth]{images/adjusted_layout}
+  \caption{Adjusted keyboard layout based on the measurements conducted in this section}
+  \label{fig:adjusted_layout}
+\end{figure}
+
+\subsection{Main user study}
+\label{sec:main_study_meth}
+\subsubsection{Hypotheses}
+\label{sec:main_hypotheses}
+Based on the literature review and preliminary telephone interviews, we derived
+the following hypotheses concerning the impact of actuation force on different
+metrics related to performance and user experience to ultimately answer our
+research question―\textit{``Does an adjusted actuation force per key have a positive
+impact on efficiency and overall satisfaction while using a mechanical
+keyboard?.''}
+
+\begin{longtable}{p{0.3cm} p{0.5cm} p{13cm} p{0.5cm}}
+  & \textbf{H1}	& Lower key actuation force improves typing speed over higher key actuation force (efficiency - speed). & \\
+  \\
+  & \textbf{H2}	& Higher key actuation force decreases typing errors compared to lower key actuation force (efficiency - error rate). & \\
+  \\
+  & \textbf{H3}	& Keys with lower actuation force are perceived as more satisfactory to type with than keys with higher actuation force. & \\
+  \\
+  & \textbf{H4}	& An adjusted keyboard (non-uniform actuation forces) improves typing speed compared to standard keyboards (uniform actuation forces) (efficiency - speed).& \\
+  \\
+  & \textbf{H5}	& An adjusted keyboard decreases typing errors compared to standard keyboards (efficiency - error rate).& \\
+  \\
+  & \textbf{H6}	& An adjusted keyboard is perceived as more satisfactory to type with compared to standard keyboards. & \\
+  \\
+  & \textbf{H7}	& Differences in actuation force influence muscle activity while typing. & \\
+\end{longtable}
+
+\subsubsection{Method}
+\label{sec:main_method}
+In our laboratory study, twenty-four participants were required to perform two
+typing test with each of the four keyboards provided by us and two extra typing
+test with their own keyboards as a reference. The four keyboards differed only
+in actuation force and were the independent variable. The dependent variable
+were, typing speed (\gls{WPM} and \gls{KSPS}), error rate (\gls{CER}, \gls{TER})
+and satisfaction (preference, usability, comfort, forearm muscle activity
+measured via \gls{EMG}, post experiment semi structured interview and ux-curves)
+
+\subsubsection{Participants}
+\label{sec:main_participants}
+There were no specific eligibility criteria for participants (n=24) of this
+study beside the ability to type on a keyboard for longer durations and with all
+ten fingers. The style used to type was explicitly not restricted to schoolbook
+touch typing to also evaluate possible effects of the adjusted keyboard on
+untrained typists. All participants recruited were personal contacts. 54\% of
+subjects were females. Participant's ages ranged from 20 to 58 years with a mean
+age of 29. Sixteen out of the twenty-four subjects (67\%) reported that they
+were touch typists. Subjects reported the following keyboard types as their
+daily driver, notebook keyboard (12, 50\%), external keyboard (11, 46\%) and
+split keyboard (1, 4\%). The keyswitch types of those keyboards were distributed
+as follows: scissor-switch (13, 54\%), rubber dome (8, 33\%) and mechanical
+keyswitches (3, 13\%). We measured the actuation force of each participants own
+keyboard and the resulting distribution of actuation forces can be observed in
+Figure \ref{fig:main_actuation_force}. The self-reported average daily usage of
+a keyboard ranged from 1 hour to 13 hours, with a mean of 6.69 hours. As already
+mentioned in Section \ref{sec:telephone_interview} it is important to note, that
+a study by Mikkelsen et al. found, that self-reported durations related to
+computer work can be inaccurate \cite{mikkelsen_duration}. All participants used
+the \gls{QWERTZ} layout and therefore were already used to the layout used
+throughout the experiment.
+
+\begin{figure}[ht]
+  \centering
+  \includegraphics[width=0.8\textwidth]{images/main_actuation_force}
+  \caption{Distribution of actuation forces from participant's own
+    keyboards. The colors represent the type of keyboard. \textit{EXT:} external
+    keyboard, \textit{NOTE:} notebook, \textit{SPLIT}, split keyboard}
+  \label{fig:main_actuation_force}
+\end{figure}
+
+\subsubsection{Experimental Environment}
+\label{sec:main_environment}
+The whole experiments took place in a room normally used as an office. Chair,
+and table were both height adjustable. The armrests of the chair were also
+adjustable in height and horizontal position. The computer used for all
+measurements featured an Intel i7-5820K (12) @ 3.600GHz processor, 16 GB RAM and
+a NVIDIA GeForce GTX 980 Ti graphics card. The operating system on test machine
+was running \textit{Arch Linux}\footnote{\url{https://archlinux.org/}}
+(GNU/Linux, Linux kernel version: 5.11.16). The setup utilized two 1080p (Full
+HD, Resolution: 1920x1080, Refresh-rate: 144Hz) monitors were participants were
+allowed to adjust the angle, height and brightness prior to the start of the
+experiment. The only two applications that were used during the experiment were
+the typing test application described in Section \ref{sec:gott} inside of the
+\textit{Chromium}\footnote{\url{http://www.chromium.org/Home}} browser (Version:
+v90.0.4430.93-r857950) and \textit{FlexVolt
+  Viewer}\footnote{\url{https://www.flexvoltbiosensor.com/software/}} (Version:
+0.2.15, Chrome App). The FlexVolt Viewer app was used to collect \gls{EMG} data
+via a bluetooth dongle (\textit{Plugable USB 2.0 Bluetooth®
+  Adapter}\footnote{\url{https://plugable.com/products/usb-bt4le/}}) from the
+\textit{FlexVolt 8-Channel Bluetooth Sensor}. Because of the ongoing COVID-19
+pandemic\footnote{\url{https://www.who.int/emergencies/diseases/novel-coronavirus-2019}},
+we ensured proper ventilation of the room and all participants including the
+researchers were tested with antigen tests prior to every appointment.
+
+\subsubsection{Independent Variable: Keyboards}
+\label{sec:main_keyboards}
+Additionally to the reference tests conducted with the participant's own
+keyboards, we provided four keyboards which only differed in terms of actuation
+force.  We decided to assign pseudonyms in the form of Greek goddesses to the
+keyboards to make fast differentiation during the sessions easier and reduce
+ambiguity. The pseudonyms for each keyboard and the corresponding actuation
+force can be found in Table \ref{tbl:kb_pseudo}. All keyboards used the standard
+ISO/IEC 9995 \cite{iso9995-2} physical layout and provided keycaps representing
+the German \gls{QWERTZ} layout, which all participants were already familiar
+with. All four keyboards used in the experiment were
+\textit{\gls{GMMK}}\footnote{\url{https://www.pcgamingrace.com/products/gmmk-full-brown-switch}}
+equipped with \textit{Gateron} mechanical
+keyswitches\footnote{\url{http://www.gateron.com/col/58459?lang=en}}. The order
+in which participants would use the four keyboards during the experiment was
+defined by a balanced latin square to reduce order effects. Additionally, the
+mentioned reference tests with \textit{Own} were conducted at the start and end
+of each session to detect possible differences in performance due to
+exhaustion. The resulting groups used during the whole experiment were as
+follows:
+
+\begin{itemize}
+  \item \textbf{Group 1:} \textit{Own $\rightarrow$ Hera $\rightarrow$ Athena $\rightarrow$ Nyx
+    $\rightarrow$ Aphrodite $\rightarrow$ Own}
+  \item \textbf{Group 2:} \textit{Own $\rightarrow$ Athena $\rightarrow$ Aphrodite $\rightarrow$ Hera
+    $\rightarrow$ Nyx $\rightarrow$ Own}
+  \item \textbf{Group 3:} \textit{Own $\rightarrow$ Aphrodite $\rightarrow$ Nyx $\rightarrow$ Athena
+    $\rightarrow$ Hera $\rightarrow$ Own}
+  \item \textbf{Group 4:} \textit{Own $\rightarrow$ Nyx $\rightarrow$ Hera $\rightarrow$ Aphrodite
+    $\rightarrow$ Athena $\rightarrow$ Own}
+\end{itemize}
+
+\begin{table}
+  \centering
+  \ra{1.3}
+  \begin{tabular}{?l^l^l^l}
+    \toprule
+    \rowstyle{\itshape}
+    Pseudonym & Actuation Force && Description\\
+    \midrule
+    \textbf{Own}       & 35 g - 65 g & $\approx$ 0.34 N - 0.64 N & Participant's own keyboard (Figure \ref{fig:main_actuation_force})\\
+    \textbf{Nyx}       & 35 g & $\approx$ 0.34 N & Uniform\\
+    \textbf{Aphrodite} & 50 g & $\approx$ 0.49 N & Uniform\\
+    \textbf{Athena}    & 80 g & $\approx$ 0.78 N & Uniform\\
+    \textbf{Hera}      & 35 g - 60 g & $\approx$ 0.34 N - 0.59 N & Non-uniform / Adjusted (Figure \ref{fig:adjusted_layout})\\
+    \bottomrule
+  \end{tabular}
+  \caption{Pseudonyms used for the keyboards throughout the experiment.}
+  \label{tbl:kb_pseudo}
+\end{table}
+
+\subsubsection{Experimental Design}
+\label{sec:main_design}
+\textbf{Preparation and Demographics}
+
+The whole laboratory experiment was conducted over a total time span of 3
+weeks. Participants were tested one at a time in sessions that in total took
+$\approx$ 120 minutes. Prior to the evaluation of the different keyboards, the
+participant was instructed to read the terms of participation which included
+information about privacy, the \gls{EMG} measurements and questionnaires used
+during the experiment. Next, participants filled out a pre-experiment
+questionnaire to gather demographic and other relevant information e.g., touch
+typist, average \gls{KB} usage per day, predominantly used keyboard type,
+previous medical conditions affecting the result of the study e.g., \glsfirst{RSI},
+\glsfirst{CTS}, etc. The full questionnaire can be observed in the appendix
+\ref{app:gott}. Further, participants could adjust the chair, table and monitor
+to a comfortable position.
+
+\textbf{\gls{EMG} Measurements}
+
+Since we measured muscle activity during all typing tests, electrodes were
+placed on the \glsfirst{FDS}/\glsfirst{FDP} and \glsfirst{ED} of both
+forearms. As already discussed in Section \ref{sec:meas_emg}, the main function
+of the \gls{FDS} and \gls{FDP} is the flexion of the medial four digits, while
+the \gls{ED} mainly extends the medial four digits. Therefore, these muscles are
+primarily involved in the finger movements required for typing on a keyboard
+\cite[650-653]{netter_anatomy}. We used ECG-Electrodes (Ag/AgCI/Solid Adhesive,
+Pregelled, Size: 43mm) from TIGA-MED Deutschland
+GmbH\footnote{\url{https://www.tiga-med.de/Diagnostik-Geraete/EKG-Elektroden-Zubehoer/EKG-Klebeelektrode-Festgel-50-Stueck-Pack}}.
+To identify the correct locations for the electrodes, participants were
+instructed to wiggle their fingers till contractions of the \gls{FDS}, \gls{FDP}
+or \gls{ED} could be felt \cite{kim_typingforces}. A reference electrode was
+placed next to the pisiform bone onto the dorsal side of the wrist. The
+locations were then shaved and subsequently cleaned with alcohol before applying
+the electrode. The distance between electrodes was 20mm. The correct placement
+was then confirmed, by observing the data received by the \textit{FlexVolt
+  8-Channel Bluetooth Sensor} in the \textit{FlexVolt Viewer} application while
+the participant performed flexion and extension of the wrist. The
+\textit{FlexVolt 8-Channel Bluetooth Sensor} used following hardware settings to
+record the data: 8-Bit sensor resolution, 32ms \gls{RMS} window size and
+Hardware smoothing filter turned off. To gather reference values (100\%\gls{MVC}
+and 0\%\gls{MVC}), which are used later to calculate the percentage of muscle
+activity for each test, we performed three measurements. First, participants
+were instructed to fully relax the \gls{FDS}, \gls{FDP} and \gls{ED} by
+completely resting their forearms on the table. Second, participants exerted
+maximum possible force with their fingers against the top of the table
+(\gls{MVC} - flexion) and lastly, participants applied maximum possible force
+with their fingers to the bottom of the table while resting their forearms on
+their thighs (\gls{MVC} - extension). We decided to also measure 0\%\gls{MVC}
+before and after each typing test and used these values to normalize the final
+data instead of the 0\%\gls{MVC} we retrieved from the initial \gls{MVC}
+measurements.
+
+
+\textbf{Familiarization with \glsfirst{GoTT} and the Keyboards}
+
+Participants could familiarize themselves with the typing test application
+(\gls{GoTT}) for up to five minutes with a keyboard that was not used during the
+experiment. Further, representative of the other keyboard models used in the
+experiment (\gls{GMMK}), participants could familiarize themselves with
+Aphrodite (50 g). Additionally, because of a possible height difference between
+\gls{GMMK} compared to notebook or other keyboards, participants were given the
+choice to use wrist rests of adequate height in combination with all four
+keyboards during the experiment. If during this process participants reported
+that an electrode is uncomfortable and that it would influence the following
+typing test, this electrode was relocated and the procedure in the last section
+was repeated (Happened one time during the whole experiment).
+
+\textbf{Texts Used for Typing Tests}
+
+As described in Section \ref{sec:gott}, we acquired ten, non-overlapping, texts
+so that every keyboard could be tested twice. The texts were labeled T0\_1,
+T0\_2, T1\_1, ..., T4\_1, T4\_2 and could be selected before each typing
+test. The order of the texts did not change during the experiment. All texts had
+almost identical \gls{FRE} scores (mean = 80.10, SD = 0.48).
+
+\textbf{Questionnaires}
+
+To receive feedback about several aspects that define a satisfactory user
+experience while using a keyboard, we decided to incorporate two questionnaires
+into our experiment. The first questionnaire was the \glsfirst{KCQ} provided by
+\cite[56]{iso9241-411} and was filled out after each individual typing test. The
+second survey, that was filled out every time the keyboard was changed, was the
+\glsfirst{UEQ-S} \cite{schrepp_ueq_handbook} with an additional question―``How
+satisfied have you been with this keyboard?''―that could be answered with the
+help of an \gls{VAS} ranging from 0 to 100 \cite{lewis_vas}. The short version
+of the \gls{UEQ} was selected, because of the limited time participants had to
+fill out the questionnaires in between typing tests (2 - 3 minutes) and also
+because participants had to rate multiple keyboards in one session
+\cite{schrepp_ueq_handbook}.
+
+
+  \item Initial typing test with own keyboard. (5 min) \\
+        Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+        Pause with light stretching exercises. (3 min)
+
+        \item \textbf{Main Part of the Experiment:} In this part the subject had
+        to take two, 5 minute, typing tests per keyboard, with a total of 4
+        keyboards (\textit{Nyx, Aphrodite, Athena, Hera}). After each typing
+        test, the subject had to fill out the post typing test survey
+        (\gls{KCQ}). Keyboards A, B and C are equipped with one set of
+        keyswitches and therefore each of the keyboards provides one of the
+        following, uniform, actuation forces across all keyswitches: 35 \gls{g},
+        50 \gls{g} or 80 \gls{g}. These specific values are the results of a
+        self conducted comparison between the product lines of most major
+        keyswitch manufacturers. The results shown in appendix
+        \ref{app:keyswitch} yield, that the lowest broadly available force for
+        keyswitches is 35 \gls{g}, the highest broadly available force is 80
+        \gls{g}, and the most common offered force is 50 \gls{g}. Keyboard D is
+        equipped with different zones of keyswitches that use appropriate
+        actuation forces according to finger strength differences and key
+        position. The keyboards used in this experiment are visually identical,
+        ISO/IEC 9995-1 conform \cite{iso9995-1} and provide a \gls{QWERTZ}
+        layout to resemble the subjects day-to-day layout and keyboard format as
+        close as possible. All keyboards are equipped with linear mechanical
+        keyswitches from one manufacturer to minimize differences in haptic and
+        sound while typing. To mitigate order effects, the order of the
+        keyboards is counterbalanced with the help of the latin square method
+        and the text snippets for the individual tests are randomized
+        \cite{statist_counterbalancing}. \textbf{(total: 80 min)}
+
+  \begin{enumerate}
+    \item \textbf{\gls{KB} A, Part 1:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+    \item \textbf{\gls{KB} A, Part 2:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+    \item \textbf{\gls{KB} C, Part 1:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+    \item \textbf{\gls{KB} C, Part 2:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+    \item \textbf{\gls{KB} B, Part 1:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+    \item \textbf{\gls{KB} B, Part 2:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+    \item \textbf{\gls{KB} D, Part 1:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+    \item \textbf{\gls{KB} D, Part 2:} Typing test. (5min) \\
+    Adjusted follow-up ISO keyboard comfort questionnaire. (2 min) \\
+    Pause with light stretching exercises. (3 min)
+  \end{enumerate}
+
+  \item Post-Test semi-structured interview: The participant has to draw three
+  different UX curves \cite{kujala_ux_curve} to evaluate how fatigue,
+  performance and overall usability of the individual keyboards were perceived
+  during the experiment. While drawing the UX curve, participants should
+  describe their thought process. To reduce errors in the later evaluation of
+  the UX curves, the entire interview is recorded. (10 min)
+
+\end{enumerate}

data/keyswitches_brands.csv

@@ -1,71 +0,0 @@
-brand,switch_name,actuation_force,type
-Cherry,MX (silent) Red,45,Linear
-Cherry,MX Speed Silver,45,Linear
-Cherry,MX (silent) Back,60,Linear
-Cherry,MX Brown,55,Tactile
-Cherry,MX Clear,65,Tactile
-Cherry,MX Grey,80,Tactile
-Cherry,MX Blue,60,Tactile + Audible
-Cherry,MX Green,80,Tactile + Audible
-Cherry,MX Low Profile Red,45,Linear
-Cherry,MX Low Profile Speed,45,Linear
-Kailh,BOX CPG1511F01S37,35,Linear
-Kailh,BOX CPG1511F01S38,45,Tactile
-Kailh,BOX CPG1511F01S02,55,Tactile + Audible
-Kailh,BOX CPG1511F01S03,60,Tactile
-Kailh,BOX CPG1511F01S04,45,Linear
-Kailh,BOX CPG1511F01S05,60,Linear
-Kailh,Choc CPG135301D03,55,Tactile + Audible
-Kailh,Choc CPG135301D02,50,Tactile
-Kailh,Choc CPG135301D01,50,Linear
-Kailh,Choc CPG135001D03,60,Tactile + Audible
-Kailh,Choc CPG135001D02,60,Tactile
-Kailh,Choc CPG135001D01,50,Linear
-Kailh,KT CPG151101D222,50,Tactile
-Kailh,KT CPG151101D223,60,Tactile + Audible
-Kailh,KT CPG151101D221,50,Linear
-Kailh,KT CPG151101D93,50,Linear
-Kailh,KT CPG151101D94,60,Linear
-Kailh,KT CPG151101D92,60,Tactile
-Kailh,KT CPG151101D91,60,Tactile + Audible
-Kailh,KT CPG151101D13,50,Tactile + Audible
-Kailh,KT CPG151101D06,50,Tactile
-Kailh,KT CPG151101D05,50,Linear
-Kailh,KT CPG151101D01,60,Linear
-Kailh,KS CPG151101D211,60,Tactile + Audible
-Kailh,KS CPG151101D213,50,Tactile
-Kailh,KS CPG151101D212,40,Linear
-Kailh,KS CPG151101D214,60,Tactile + Audible
-Kailh,KS CPG151101D215,50,Tactile + Audible
-Kailh,KS CPG151101D218,70,Linear
-Kailh,KS CPG151101D219,70,Linear
-Kailh,KS CPG151101D220,70,Tactile + Audible
-Kailh,KS CPG151101D234,70,Tactile + Audible
-Kailh,KH CPG128001S03,45,Tactile
-Kailh,KH CPG128001S02,45,Tactile + Audible
-Kailh,KH CPG128001S01,45,Linear
-Kailh,KO RGB CPG159301S09,50,Tactile + Audible
-Kailh,KO RGB CPG159301S08,50,Tactile
-Kailh,KO RGB CPG159301S07,50,Linear
-Kailh,Sun CPG1511B01D03,50,Tactile + Audible
-Gateron,Clear,35,Linear
-Gateron,Red,45,Linear
-Gateron,Black,50,Linear
-Gateron,Blue,55,Tactile + Audible
-Gateron,Green,80,Tactile + Audible
-Gateron,Brown,45,Tactile
-Gateron,Yellow,50,Linear
-Matias,Quiet Linear,35,Linear
-Matias,Quiet Click,60,Tactile
-Matias,Standard Click,60,Tactile + Audible
-Razer,Green,50,Tactile + Audible
-Razer,Orange,45,Tactile
-Razer,Yellow,45,Linear
-Logitech,GL Tactile,50,Tactile
-Logitech,GL Linear,50,Linear
-Logitech,GL Clicky,50,Tactile + Audible
-Logitech,Romer-G Tactile,45,Tactile
-Logitech,Romer-G Linear,45,Linear
-Logitech,GX Blue,50,Tactile + Audible
-Logitech,GX Brown,50,Tactile
-Logitech,GX Red,50,Linear

glossary.tex

@@ -7,6 +7,7 @@
 \newacronym{RSI}{RSI}{Repetitive Strain Injury}
 \newacronym{FRE}{FRE}{Flesch Reading Ease Score}
 \newacronym{VAS}{VAS}{visual analog scale}
+\newacronym{RMS}{RMS}{root-mean-square}
 % Mulcles alive p. 189
 % Atlas of Human Anatomy p. 433
 \newacronym{FDS}{FDS}{flexor digitorum superficialis}
@@ -33,6 +34,7 @@
 \newacronym{PTTQ}{PTTQ}{post typing test questionnaire}
 \newacronym{PKQ}{PKQ}{post keyboard questionnaire}
 \newacronym{OLED}{OLED}{organic light-emitting diode}
+\newacronym{GMMK}{GMMK}{Glorious Modular Mechanical Keyboards}
 
 \newglossaryentry{N}{
 name={N},

scripts/keyswitches_brands.py

@@ -1,12 +0,0 @@
-import seaborn as sns
-import matplotlib.pyplot as mp
-from pandas import read_csv
-
-sns.set_theme(style="white", color_codes=True)
-sns.set_palette("colorblind")
-
-switches = read_csv("../data/keyswitches_brands.csv")
-
-axis = sns.countplot(data=switches, x="actuation_force")
-axis.set(ylabel="Number of available Keyswitches", xlabel="Actuation force ± 2 g")
-mp.savefig("../images/keyswitches_brands.png")

thesis.tex

@@ -24,7 +24,7 @@
 \BeforeBeginEnvironment{minted}{\begin{mdframed}}
 \AfterEndEnvironment{minted}{\end{mdframed}}
 \usepackage{booktabs}
-\usepackage{tabularx}
+% \usepackage{tabularx}
 \newcommand{\ra}[1]{\renewcommand{\arraystretch}{#1}}
 \usepackage{array}
 \newcolumntype{?}{>{\global\let\currentrowstyle\relax}}
@@ -32,6 +32,7 @@
 \newcommand{\rowstyle}[1]{\gdef\currentrowstyle{#1}%
   #1\ignorespaces
 }
+\newcommand{\centered}[1]{\begin{tabular}{@{}c@{\hskip 0.13cm}l@{}} #1 \end{tabular}}
 % \usepackage{mathpazo}
 
 % verbesserter Randausgleich