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