\section{Motivation}
\label{sec:label}


% In recent years, computers are used to some extend in almost every industry in
% Europe \cite{eurostat_ent_w_comp} and China \cite{iresearch_ent_w_comp}. This
% leads to the conclusion, that also other countries must have a high usage of
% computers in corporations. Furthermore, according to a statistic published by
% \citeauthor{itu_hh_w_comp} in 2019, nearly half of the worldwide households have
% access to at least one computer \cite{itu_hh_w_comp}. One of the most used
% devices for data input while operating a computer is the keyboard
% \parencite[22]{handbook_chi}. Therefore, people who use a computer, either at
% home or to fulfill certain tasks at work, are also likely to use a keyboard. An
% important part of a keyboard is the keyswitch also called keyboard key or
% key. Those keyswitches use, depending on the manufacturer or keyboard type,
% different mechanisms to actuate a keypress. More commonly used mechanism to date
% are scissor switches, mostly used in laptop keyboards, rubber dome and membrane switches,
% often used in low- to mid-priced keyboards, and mechanical switches which are
% the main switch type for high-end and gaming keyboards
% \cite{ergopedia_keyswitch}. Depending on the mechanism and type of key used, it
% is possible that different force has to be applied to the key to activate
% it. Normally, the force required to activate a key is identical for each key
% across the keyboard. However, previous research has shown, that there is a
% disparity in force generated by different fingers
% \cite{bretz_finger_force}. This raises the question, why there are no keyboards
% for personal or work related use cases with adjusted actuation forces per finger
% or even customizable keyboards, where an individual can select the actuation
% force for each keyswitch individually.

In recent decades, computers and other electronic devices have become an
indispensable part of everyday life. Computers are used in almost every industry
\cite{iresearch_ent_w_comp, eurostat_ent_w_comp} and 84\,\% of European
households as well as nearly half of the worldwide households have access to at
least one computer \cite{eurostat_hous_w_comp, itu_hh_w_comp}. Even 153 years
after the first typewriter was patented \cite{noyes_qwerty} people still mostly
use identical looking keyboards as their main way to input data into a computer
\parencite[22]{handbook_chi} \& \cite{broel_dektop_or_smartphone}. A potential
problem while interacting with a computer through the usage of a keyboard are
rapid movements of the fingers over a prolonged time, which can cause discomfort
and increase the risk for \gls{WRUED} \cite{pascarelli_wrued,
  ccfohas_wrued}. Previous research has shown, that the actuation force, which
is the force required to generate a keypress, is directly related to the actual
force an individual generates to press a specific key
\cite{gerard_keyswitch}. Also, the individual fingers are not capable of
exerting identical force, which could lead to higher fatigue in weaker fingers
\cite{bretz_finger, martin_force, baker_kinematics, dickson_finger}. There are
various designs for alternative keyboards by e.g.,
Maltron\footnote{\url{https://www.maltron.com/store/c47/Dual_Hand_Keyboards.html}},
Ergodox\footnote{\url{https://www.ergodox.io/}}, Kenesis
\footnote{\url{https://kinesis-ergo.com/keyboards/advantage2-keyboard/}},
etc. Due to the oftentimes unusual layouts and extra keys for the thumbs, all
these keyboards require the typist to adjust to a completely new way of typing
and therefore could reduce productivity during this adjustment
phase. Additionally, a study by Baker et al. (n = 77) revealed, that even after
several months of using a keyboard with an alternative design, in terms of
usability, participants still preferred the traditional design because of its
superb usability \cite{baker_ergo2}. With these insights, the uniformity of
actuation force across conventional keyboards may be a potential characteristic
that could be improved on, to reduce the strain on weaker fingers and thus
reduce fatigue and increase comfort. Therefore, a keyboard with, per key,
adjusted actuation force, depending on the finger usually operating the key,
might be a feasible solution without the requirement for typists to invest in
higher priced alternative keyboards, which also require additional
familiarization. To become a successful alternative, the adjusted keyboard
design has to perform equally good or even better than existing conventional
keyboard designs, while also enhancing the user experience during usage. These
requirements led to the following research question of this thesis:

\vspace{1em}
\begin{tabular}{p{0.3cm} p{0.5cm} p{13cm} p{0.5cm}}
  & \textbf{\large RQ}	& {Does an adjusted actuation force per key have a positive impact on efficiency and overall satisfaction while using a mechanical keyboard?} & \\
\end{tabular}
\vspace{1em}

If this question could be positively answered, companies producing keyboards
could implement the proposed adjustments in actuation force into existing
manufacturing processes and thereby make adjusted keyboard designs broadly
available and potentially keep the retail prices acceptably low.



% This raises the question, if keyboards for
% personal or work related use cases with adjusted actuation forces per finger or
% even customizable keyboards, where an individual can select the actuation force
% for each keyswitch individually.

% Depending on the mechanism and type of key used, it
% is possible that different force has to be applied to the key to activate
% it. Normally, the force required to activate a key is identical for each key
% across the keyboard. However, previous research has shown, that there is a
% disparity in force generated by different fingers
% \cite{bretz_finger_force}. This raises the question, why there are no keyboards
% for personal or work related use cases with adjusted actuation forces per finger
% or even customizable keyboards, where an individual can select the actuation
% force for each keyswitch individually.

% Input tasks are not only restricted to pure data entry but also include complex
% inputs required by games.