diff --git a/abstractDE.tex b/abstractDE.tex index e7d1b0f..039e916 100644 --- a/abstractDE.tex +++ b/abstractDE.tex @@ -9,7 +9,7 @@ Computer arbeiten. Einige Benutzer:innen empfinden jedoch irgendwann Unbehagen oder sogar Schmerzen bei der Verwendung einer Tastatur, da die Finger viele kleine und sich wiederholende Bewegungen ausführen müssen, um die Tasten zu bedienen. Daher versuchen wir in dieser Bachelorarbeit, ein alternatives, nicht -uniformes Tastaturdesign zu evaluieren, bei dem jede einzelne mechanische Taste +uniformes Tas\-taturdesign zu evaluieren, bei dem jede einzelne mechanische Taste mit einer Feder ausgestattet ist, die einen Widerstand aufweist, der dem spezifischen Finger entspricht, der sie normalerweise bedient. Die Idee hinter diesem angepassten Design ist, insbesondere die schwächeren Finger zu entlasten @@ -19,13 +19,13 @@ Finger angepassten Betätigungskraft einen positiven Einfluss auf die Effizienz und die allgemeine Zufriedenheit während der Benutzung hat. Darum haben wir die aktuelle Verfügbarkeit von Widerständen für mechanische Tastenschalter evaluiert und eine erste telefonische Befragung (n = 17) durchgeführt, um Präferenzen, -Anwendungsfälle und bisherige Erfahrungen mit Tastaturen zu ermitteln. Darüber +Anwendungsfälle und bisherige Erfahrungen mit Tas\-taturen zu ermitteln. Darüber hinaus führten wir ein weiteres Experiment durch, bei dem wir die maximal ausübbare Kraft für jeden Finger in verschiedenen, mit dem Drücken einer Taste verbundenen Positionen maßen und im Anschluss als Grundlage für unser angepasstes Tastaturdesign verwendeten. Schließlich wurden in einer dreiwöchigen Laborstudie mit 24 Teilnehmern das angepasste Tastaturdesign und drei -herkömmliche Tastaturen mit 35 g, 50 g und 80 g Betätigungskraft in Bezug auf +herkömmliche Tastaturen mit 35\,g, 50\,g und 80\,g Betätigungskraft in Bezug auf Leistung und allgemeine Zufriedenheit miteinander verglichen. Die statistische Auswertung ergab, dass vor allem die Fehlerquote durch höhere Betätigungskräfte positiv beeinflusst wird und dass Tastaturen mit weder zu hohem noch zu geringem @@ -39,4 +39,4 @@ das angepasste Design aufgrund der gleich guten Ergebnisse immer noch eine brauchbare Alternative ist und mit weiteren Verbesserungen, z. B. einer vollständigen Personalisierung des Federwiderstands für jede Taste, möglicherweise das Erlebnis bei der Verwendung und die Leistung für -anspruchsvolle Benutzer:innen verbessern könnte. +anspruchsvolle Benutzer:innen verbessert werden könnte. diff --git a/abstractEN.tex b/abstractEN.tex index e1a4f5c..09d2c1a 100644 --- a/abstractEN.tex +++ b/abstractEN.tex @@ -20,12 +20,12 @@ with keyboards. Further, we ran another preliminary experiment, where we measured the maximum applicable force for each finger in different positions related to keyboarding as a basis for our adjusted keyboard design. Lastly, during a three week laboratory user study with twenty-four participants, the -adjusted keyboard design and three traditional keyboards with 35 g, 50 g and 80 -g actuation force where compared to each other in terms of performance and user +adjusted keyboard design and three traditional keyboards with 35\,g, 50\,g and 80 +g actuation force were compared to each other in terms of performance and user satisfaction. The statistical analysis revealed, that especially error rates are positively influenced by higher actuation forces and that keyboards with neither -to heavy nor to light resistance generally perform the best in terms of typing -speed. Further, the adjusted keyboard and the 50 g keyboard performed almost +too heavy nor to light resistance generally perform the best in terms of typing +speed. Further, the adjusted keyboard and the 50\,g keyboard performed almost identically in all tests and therefore we could not derive any significant improvements in performance or satisfaction over traditional designs that utilize keyswitches with moderate resistance. However, we concluded, that with diff --git a/appendices.tex b/appendices.tex index 3a4520b..9bba426 100644 --- a/appendices.tex +++ b/appendices.tex @@ -28,7 +28,7 @@ \pagebreak -\subsection{UX-Curves for All Participants and All Groups} +\subsection{\Gls{UX Curve}s for All Participants and All Groups} \label{app:uxc} \begin{figure}[H] @@ -42,4 +42,12 @@ \begin{figure}[H] \centering \includegraphics[width=1.0\textwidth]{images/collage} -\end{figure} \ No newline at end of file +\end{figure} + +\subsection{The Four Test Keyboards} +\label{app:equipment} + +\begin{figure}[H] + \centering + \includegraphics[width=1.0\textwidth]{images/keyboards} +\end{figure} diff --git a/chap0/sec1.tex b/chap0/sec1.tex deleted file mode 100644 index d38b4b9..0000000 --- a/chap0/sec1.tex +++ /dev/null @@ -1,212 +0,0 @@ -% Chapter 0 - Proposal -% Section 1 - Motivation, problem statement and thesis objectives -\section{Bachelor Thesis Proposal - Philip Gaber} -{\huge Impact of adjusted, per key, actuation force on efficiency and satisfaction while using mechanical keyboards} -\subsection{Motivation} -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, dome/membrane switches, -often used in low- to mid-priced keyboards, and mechanical switches which are -the main switch type for high-priced 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. - -\subsection{Proposed Objective, Research Question and Hypothesis} - -% This thesis is intended to provide an overview of already conducted research in -% the domain of keyboards, especially in connection with actuation force and the -% impact of different keyswitches on keyboard users. - -% Because there is no previous research in the particular field of per finger/key -% actuation force for (mechanical) keyboards and the impact of such customization -% on efficiency and comfort, this thesis is also intended to research if this is a -% viable option in comparison to the classic keyboard with uniform actuation -% force. Therefore the author proposes to answer the question: - -This thesis is intended to research if a keyboard with zones of keys, which have -adjusted actuation force depending on the assigned finger for that zone and the -position on the keyboard, is a viable option compared to the standard keyboard -with uniform actuation force across all keyswitches. - -\begin{tabular}{p{0.3cm} p{0.5cm} p{13cm} p{0.5cm}} - & \textbf{\large RQ} & {\Large 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} - -% TODO: Dissatisfied statt comfort da hohe error rate und dadurch frustriert -% TODO: Bei hypothesen noch error rate bei geschwindigkeit mit einbeziehen -% ASK: Doch noch comfort mit einbeziehen? -\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 write with than keys with higher actuation force. & \\ - & & & \\ - & \textbf{H4} & Users perform better and feel more satisfied while using Keyboards with adjusted key actuation force than without the adjustment. & \\ -\end{longtable} - - -\section{Proposed Method} - -\subsection{Subjects} - -It is planned to recruit 20 participants in total. Main target group to recruit -participants for the research study from are personal contacts and fellow -students. Participants are required to type with more than just one finger per -hand. Thus, touch typing is not a mandatory but helpful skill to -participate. The age distribution for the subjects is estimated to be between 18 -and 56 years. The average typing speed should be known prior to the main -experiment. Therefore, a typing speed test should be performed on the subject's -own keyboard in beginning of the experiment. This typing test has to be -performed within the standardized test environment consisting of an adjustable -chair, desk, monitor and the typing test software used within the main -experiment. Also, all subjects have to give their written consent to -participate in the study. - -\subsection{Study design} - -Participants must complete several typing tests using four different keyboards. - -The experiment should consist of a experimental group and a control group. The -control group will perform all typing tests with the same keyboard. The text -used for the typing test should be easily understandable. Therefore, the text -has to be evaluated with the help of a \gls{FRE} \cite{flesch_fre} -adjusted for German language \cite{immel_fre}. - -\begin{equation}\label{fre_german} - FRE_{deutsch} = 180 - \underbrace{ASL}_{\mathclap{\text{Average Sentence Length}}} - (58,5 * \overbrace{ASW}^{\mathclap{\text{Average Syllables per Word}}}) -\end{equation} - -The adjusted formula (\ref{fre_german}) to estimate the understandability of the -texts used in this experiment usually yields a number in the range of -\([0;100]\) called the \gls{FRE}. Higher \gls{FRE}s refer to better -understandability and thus the texts used in this experiment all have to fulfill -the requirement of a \gls{FRE} \(> 70\), which represents a fairly easy text -\cite{immel_fre} and \cite{flesch_fre}. - -One typing test will consist of several smaller, randomly chosen, texts -snippets. The length of the snippets has to be between 100 and 400 characters -and a snippet has to meet the \gls{FRE} requirement. The snippets are generated by -volunteers via the web interface of the platform used in this experiment which -can be seen in appendix \ref{app:gott}. - -% ASK: Should there be a control group at all, if so should they use their own keyboard or always the same random keyboard while they think they are testing different keyswitches? -After each typing test, the participant has to fill out an adjusted CEN ISO/TS -9241-411:2014 keyboard comfort questionnaire \cite{iso9241-411}. One additional -question was added to this questionnaire: ``How satisfied have you been with -this keyboard?'' The answer for this question can be selected with the help of a -\gls{VAS} ranging from 0 to 100 \cite{lewis_vas}. - -\textbf{Planned experiment procedure: (Total time requirement: 120 min)} - -\begin{enumerate} - \item Pre-Test 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., \gls{RSI}, \gls{CTS}, etc. The full questionnaire can be observed - in the appendix \ref{app:gott}. (5 min) - - \item Adjustment of the test environment (Chair height, monitor height, etc.) (2 min) - \item Prepare subject for \gls{EMG} measurements: Electrodes are placed on the - \gls{FDS}/\gls{FDP} and \gls{ED} of both forearms. 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{netter_anatomy}. (8 min) - \item Familiarization with the typing test and keyboard model used in the experiment. All participants use the same keyboard with 50g actuation force for this step. (5 min) - \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) - % SUBTOTAL: 30 min - - \item \textbf{Main Test (H1-H4):} In this part the subject has to - take two, 5 minute, typing tests per keyboard, with a total of 4 - keyboards (\gls{KB} A, \gls{KB} B, \gls{KB} C, \gls{KB} D). After each - typing test, the subject has to fill out the post typing test keyboard - comfort questionnaire. 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} - -The \gls{EMG} data for all muscles is captured using the Flexvolt Chrome app and Flexvolt 8-Channel -biosensor device in combination with TIGA-MED ECD-Electrodes. The captured data is then processed and -plotted using Python. Hardware and plots can be observed in Figure \ref{fig:emg_setup}. - -\begin{figure}[h] - \centering - \includegraphics[width=1.0\textwidth]{images/emg_setup.jpg} - \caption{Flexvolt 8-Channel Biosensor and example plots of \gls{EMG} data} - \label{fig:emg_setup} -\end{figure} - -This test scenario is inspired by the tests conducted in \cite{kim_typingforces}. \ No newline at end of file diff --git a/chap1/introduction.tex b/chap1/introduction.tex index fee6abd..bca2f91 100644 --- a/chap1/introduction.tex +++ b/chap1/introduction.tex @@ -29,11 +29,11 @@ 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 +\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 @@ -42,29 +42,29 @@ and increase the risk for \gls{WRUED} \cite{pascarelli_wrued, 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 and therefore fatigue must be higher for weaker fingers +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. which, because of the often unusual layouts and extra keys for the thumbs, -all 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 research question of -this thesis: +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}} diff --git a/chap2/literature_review.tex b/chap2/literature_review.tex index 1e20960..ef66a77 100644 --- a/chap2/literature_review.tex +++ b/chap2/literature_review.tex @@ -17,12 +17,12 @@ results of previous research. \label{sec:wrued} \Gls{WRUED} is a term to describe a group of medical conditions related to muscles, tendons and nerves in shoulder, arm, elbow, forearm or hand, such as -e.g., \gls{CTS}, \gls{RSI}, tendonitis, tension neck syndrome, etc. Symptoms of +\gls{CTS}, \gls{RSI}, Tendinitis, \gls{TNS}, etc. Symptoms of \gls{WRUED} are aching, tiredness and fatigue of affected regions that either occur while working or even extend to phases of relaxation. A common way to treat \gls{WRUED} is to avoid the potentially harmful activities that cause discomfort in affected areas \cite{ccfohas_wrued}. Pascarelli and Hsu reported, -that out of 485 patients with \gls{WRUED} 17\% were computer users +that out of 485 patients with \gls{WRUED} 17\,\% were computer users \cite{pascarelli_wrued}. Since computers have become an essential part of many jobs in almost any sector of employment, restrictions of computer related activities would result in either reduced productivity or the complete inability @@ -125,9 +125,9 @@ separating the two plates which closes the electrical circuit and sends a keypress to the computer. After the key is released, the spring pushes the stem back to its original position \cite{bassett_keycap, peery_3d_keyswitch, ergopedia_keyswitch, chen_mech_switch}. Usually, mechanical keyswitches are -directly soldered onto the \gls{PCB} of the keyboard but there are also -keyboards where the \gls{PCB} features special sockets where the keyswitches can -be hot-swapped without soldering at all \cite{gmmk_hot_swap}. It is also +directly soldered onto the \gls{PCB} of the keyboard. However, there are also +keyboards with \gls{PCB}s that feature special sockets where the keyswitches can +be \gls{swapped} without soldering at all \cite{gmmk_hot_swap}. It is also possible to equip an already existing \gls{PCB} with sockets to make it hot-swappable \cite{te_connect}. @@ -147,27 +147,27 @@ primarily define if and how feedback for a keypress is realised: \item \textbf{Tactile Switches} utilize a small bump on the stem to slightly increase and then instantly collapse the force required immediately before the actual actuation happens \cite{cherry_mx_brown}. This provides the typist with - a short noticeable haptic feedback and which should encourage a premature + a short noticeable haptic feedback, which should encourage a premature release of the key. An early study by Brunner and Richardson suggested, that - this feedback leads to faster typing speeds and a lower error rate in both + this feedback leads to faster typing speed and a lower error rate in both experienced and casual typists (n=24) \cite{brunner_keyswitch}. Contrary, a - study by Akagi yielded no significant differences in terms of speed and error + study by Akagi yielded no significant differences in terms of speed nor error rate between tactile and linear keyswitches and links the variation found in error rates to differences in actuation force (n=24) \cite{akagi_keyswitch}. Tactile feedback could still assist the typist to prevent \gls{bottoming}. \item \textbf{Tactile and audible Switches (Clicky)} separate the stem into - two parts, the lower part also features a small bump to provide tactile + two parts. The lower part also features a small bump to provide tactile feedback and is also responsible for a distinct click sound when the actuation happens \cite{cherry_mx_blue}. Gerard et al. noted, that in their study - (n=24), keyboards with audible feedback increased typing speed and decreased + (n=24) keyboards with audible feedback increased typing speed and decreased typing force. This improvement could have been due to the previous experience of participants with keyboards of similar model and keyswitch characteristic \cite{gerard_keyswitch}. \item \textbf{Linear Switches} do not offer a distinct feedback for the typist. The activation of the keyswitch just happens after approximately half the total travel distance \cite{cherry_mx_red}. The only tactile feedback that - could happen is the impact of \gls{bottoming}, but with enough practice, + could happen is the impact of \gls{bottoming}. However, with enough practice typist can develop a lighter touch which reduces overall typing force and therefore reduces the risk of \gls{WRUED} \cite{gerard_keyswitch, peery_3d_keyswitch, fagarasanu_force_training}. @@ -192,7 +192,7 @@ forces. Actuation force, also sometimes referred to as make force, is the force required to activate the keyswitch \cite{radwin_keyswitch, ergopedia_keyswitch}. That means depending on the mechanism used, activation describes the closing of an electrical circuit which forwards a signal, that is -then processed by a controller inside of the keyboard and finally send to the +then processed by a controller inside of the keyboard and finally sent to the computer. The computer then selects the corresponding character depending on the layout used by the user. Previous studies have shown, that actuation force has an impact on error rate, subjective discomfort, muscle activity and force @@ -202,7 +202,7 @@ typing speed, which could be more significant with greater variation of actuation force across tested keyboards \cite{loricchio_force_speed}. \begin{phga_sum*} -Since this thesis is focused around keyboards and especially the relation +Since this thesis is focused on keyboards and especially the relation between the actuation force of the keyswitch and efficiency (speed, error rate) and also the differences in satisfaction while using keyswitches with varying actuation forces, it was important to evaluate different options of keyswitches @@ -217,14 +217,14 @@ each key should have an adjusted actuation force depending on the finger that normally operates it. It should be mentioned, that it is theoretically possible to exchange individual rubber dome switches on some keyboards, e.g. keyboards with \gls{Topre} switches, but the lacking availability of compatible keyboards -and especially the limited selection of actuation forces (30g to 55g for +and especially the limited selection of actuation forces (30\,g to 55\,g for \gls{Topre} \cite{realforce_topre}) makes this not a viable option for this thesis \cite{keychatter_topre}. Therefore, we decided to use mechanical -keyswitches for our experiment, because these keyswitches are broadly available +keyswitches for our experiment. These keyswitches are broadly available in a variety of actuation forces and because the spring which mainly defines the actuation force can be easily replaced with any other compatible spring on the market, the selection of actuation forces is much more appropriate for our use -case (30g to 150g) \cite{peery_3d_keyswitch}. We also decided to use linear +case (30\,g to 150\,g) \cite{peery_3d_keyswitch}. We also decided to use linear switches because they closest resemble the feedback of the more wide spread rubber dome switches. Further, linear switches do not introduce additional factors beside the actuation force to the experiment. In addition, based on the @@ -248,15 +248,16 @@ is transcribed \cite{chen_typing_test, hoffmann_typeright, \subsubsection{Readability of Text} \label{sec:meas_fre} -Text used should be easy to read for typists -participating in studies that evaluate their performance and are therefore is -chosen based on a metric called the \gls{FRE} which indicates the -understandability of text \cite{fagarasanu_force_training, - kim_typingforces, flesch_fre}. The score ranges from 0 which implies very poor reading -ease to 100 suggesting that the style of writing used causes the text to be very -easy to comprehend \cite{flesch_fre}. Immel proposed an adjusted formula of the -\gls{FRE} that is suitable for German text \cite{immel_fre} and can be seen in -(\ref{eq:fre_german}). +The texts used should be easy to read for typists participating in studies that +evaluate their performance and are therefore chosen based on a metric called the +\gls{FRE} which indicates the understandability of text +\cite{fagarasanu_force_training, kim_typingforces, flesch_fre}. The score ranges +from 0 which implies very poor reading ease to 100 suggesting that the style of +writing used causes the text to be very easy to comprehend +\cite{flesch_fre}. Immel proposed an adjusted formula of the \gls{FRE} that is +suitable for German text \cite{immel_fre} and can be seen in +(\ref{eq:fre_german}). This formula was necessary, because all participants were +Germans. \begin{equation}\label{eq:fre_german} FRE_{deutsch} = 180 - \underbrace{ASL}_{\mathclap{\text{Average Sentence Length}}} - (58,5 * \overbrace{ASW}^{\mathclap{\text{Average Syllables per Word}}}) @@ -344,7 +345,7 @@ In several other studies, in addition to the metrics mentioned so far, \gls{EMG} data was captured to evaluate the muscle activity or applied force while typing on completely different or modified hardware \cite{kim_typingforces, fagarasanu_force_training, gerard_audio_force, gerard_keyswitch, martin_force, - rose_force, rempel_ergo, pereira_typing_test}. \gls{EMG} signals, are captured + rose_force, rempel_ergo, pereira_typing_test}. \gls{EMG} signals are captured with the help of specialized equipment that utilize electrodes which are either placed onto the skin above the muscles of interest (non-invasive) or inserted directly into the muscle (invasive). The disadvantage of non-invasive surface @@ -379,7 +380,7 @@ and satisfaction, are evaluated based on survey data collected after participants used different input methods \cite{kim_typingforces, bell_pauseboard, bufton_typingforces, pereira_typing_test, iso9241-411}. In their study, Kim et al. used a modified version of the \gls{KCQ} provided by the -\gls{ISO} which is specifically designed to evaluate different keyboards in +\gls{ISO}, which is specifically designed to evaluate different keyboards in terms of user satisfaction, comfort and usability \cite{kim_typingforces, iso9241-411}. This survey poses a total of twelve questions concerning e.g., fatigue of specific regions of the upper extremity, general satisfaction with @@ -392,7 +393,7 @@ categories \cite{nguyen_ueq, olshevsky_ueq, gkoumas_ueq}. While the full (attractiveness, perspicuity, efficiency, dependability, stimulation and novelty), the \gls{UEQ-S} only features 8 questions and two scales (pragmatic and hedonic quality). Because of the limited explanatory power of the -\gls{UEQ-S}, it is recommended to only use it, if there is not enough time to +\gls{UEQ-S}, it is recommended to only use it if there is not enough time to complete the full \gls{UEQ} or if the participants of a study are required to rate several products in one session \cite{schrepp_ueq_handbook}. @@ -416,9 +417,9 @@ As already discussed in Section \ref{sec:metrics}, it is common practice in research related to typing to present a text that has to be transcribed by the participant. Usually, the text was chosen by the researcher or already available through the used typing test software. If the understandability of text is of -concern, the binary choice of, is understandable or not, made by the researcher +concern, the binary choice of―is understandable or not―made by the researcher could lead to a phenomenon called the observer bias \cite{hrob_observer, - berger_observer, angrosino_observer}. Thus, the text could potentially be to + berger_observer, angrosino_observer}. Thus, the text could potentially be too difficult to understand for the participants if not evaluated with e.g. the \gls{FRE} or other adequate formulas. Further, if there is previous knowledge about the requested participants, the researcher could subconsciously select @@ -457,31 +458,31 @@ models. One difference was the applied force, a keyswitch required to activate. A study by Akagi tested the differences in performance and preference across four visually identical keyboards with different keyswitches. The keyswitches differed in actuation force and type. Two keyboards used tactile -keyswitches with 70.9 g (\gls{KB} A) and 32.5 g (\gls{KB} C) the other two -linear switches with 70.9 g (\gls{KB} D) and 42.5 g (\gls{KB} B). The (n=24) +keyswitches with 70.9\,g (\gls{KB} A) and 32.5\,g (\gls{KB} C) the other two +linear switches with 70.9\,g (\gls{KB} D) and 42.5\,g (\gls{KB} B). The (n=24) subjects were required to type on each keyboard for 7 to 8 minutes where speed -and errors were recorded. The results showed, that \gls{KB} D (linear, 70.9 g) -produced the lowest error rate followed by \gls{KB} A (tactile, 70.9 g), -\gls{KB} C (linear, 42.5 g) and \gls{KB} B (tactile, 35.5 g). Further, the -difference in typing speed between the slowest (tactile, 70.9 g) and fastest -(linear, 42.5 g) keyboard was only 2.61\% and according to Akagi too small to be +and errors were recorded. The results showed, that \gls{KB} D (linear, 70.9\,g) +produced the lowest error rate followed by \gls{KB} A (tactile, 70.9\,g), +\gls{KB} C (linear, 42.5\,g) and \gls{KB} B (tactile, 35.5\,g). Further, the +difference in typing speed between the slowest (tactile, 70.9\,g) and fastest +(linear, 42.5\,g) keyboard was only 2.61\,\% and according to Akagi too small to be significant in practical use. The study also revealed, that the preference for neither of the four keyboards was significantly different \cite{akagi_keyswitch}. A follow up survey by Akagi concerning the model of -keyboard typists would prefer to use in the future revealed, that 69\% of the 81 -participating decided for a newly proposed keyboard with 56.7 g resistance and +keyboard typists would prefer to use in the future revealed, that 69\,\% of the 81 +participating decided for a newly proposed keyboard with 56.7\,g resistance and light tactile feedback \cite{akagi_keyswitch}. Further, a study by Loricchio, -were (n=16) participants typed on two identical keyboard models that only -differed in actuation force (58 g and 74g), also yielded moderate differences in -typing speed. The keyboard with lower actuation force was 8.25\% faster and +where (n=16) participants typed on two identical keyboard models that only +differed in actuation force (58\,g and 74\,g), also yielded moderate differences in +typing speed. The keyboard with lower actuation force was 8.25\,\% faster and preferred by 15 out of the 16 subjects compared to the keyboard featuring keyswitches with higher actuation force \cite{loricchio_force_speed}. A study by Hoffmann et al. even designed a keyboard that utilized small electromagnets―instead of the typically used spring―to dynamically alter the resistance of keys to prevent erroneous input by increasing the force required to press keys that do not make sense in the current context of a word. This -design reduced the number of required corrections by 46\% and overall lowered -typos by 87\% compared to when the force feedback was turned off (n=12) +design reduced the number of required corrections by 46\,\% and overall lowered +typos by 87\,\% compared to when the force feedback was turned off (n=12) \cite{hoffmann_typeright}. \begin{phga_sum*} @@ -490,16 +491,16 @@ different results pertaining speed, but agreed that actuation force influences the error rate during typing related tasks. To our best knowledge, there are no studies that evaluated the effect of non-uniformly distributed actuation forces across one keyboard on speed, accuracy, error rate or preference. This is why we -want to reevaluate the influence of actuation force on speed and determine, if +want to reevaluate the influence of actuation force on speed and determine if keyboards with non-uniform actuation forces have a positive impact on all -metrics mentioned so far. The next section gives insights, into why such +metrics mentioned so far. The next section gives insights into why such keyboards could make sense. \end{phga_sum*} \subsection{Strength of Individual Fingers} As already mentioned in Section \ref{sec:mech_switch}, the force applied to a keyswitch is the concern of multiple studies that evaluate the relation between -keyboarding and \gls{WRUED}. Further, multiple studies came to the conclusion, +keyboarding and \gls{WRUED}. Further, multiple studies came to the conclusion that there is a significant discrepancy in strength between individual fingers \cite{bretz_finger, martin_force, baker_kinematics, dickson_finger}. Bretz et al. found, that when participants squeezed an object between thumb and finger, @@ -519,7 +520,7 @@ The goal of this thesis is to evaluate the possible advantages of keyboards with non-uniform actuation forces. The fairly small difference of only 0.08 \gls{N} in mean force applied to keyboards recorded by Martin et al. \cite{martin_force} but rather big difference in finger strength measured by Bretz et -al. \cite{bretz_finger} could indicate, that albeit the difference in strength, +al. \cite{bretz_finger} could indicate that albeit the difference in strength, all fingers have to apply equal force to generate a keypress because of the uniform actuation force used in commercially available keyboards. \end{phga_sum*} @@ -546,9 +547,9 @@ is feasible to evaluate possible alternative input methods to the more traditional keyboard. The availability of affordable surface level \gls{EMG} measurement devices makes it possible for researchers that are not medically trained to conduct non-invasive muscle activity measurements \cite{takala_emg} -and load cells in combination with micro controllers are a reliable, low-cost -solution to visualize the strength of different fingers and monitor applied -forces while typing \cite{gerard_keyswitch, rempel_ergo, +In addition, load cells in combination with micro controllers are a reliable, +low-cost solution to visualize the strength of different fingers and monitor +applied forces while typing \cite{gerard_keyswitch, rempel_ergo, bufton_typingforces}. Although, the strength of individual fingers has already been measured in different studies \cite{bretz_finger, martin_force, baker_kinematics, dickson_finger}, to our best knowledge, there are no diff --git a/chap3/implementation.tex b/chap3/implementation.tex index 9803310..369e826 100644 --- a/chap3/implementation.tex +++ b/chap3/implementation.tex @@ -1,12 +1,12 @@ \section{Development and Implementation of Necessary Tools} For the purpose of this thesis, we programmed our own typing test platform to have better control over the performance related measurements and the text that -has to be transcribed. Further, the participants had to fill out up to two -questionnaires after each typing test which had to be linked to this specific -typing test or keyboard. With a total number of 24 subjects, five keyboards and -therefore 10 individual typing tests per subject or 240 typing tests in total, -we decided to incorporate a questionnaire feature into our platform to mitigate -the possibility of false mappings between typing tests, surveys and +has to be transcribed. The participants had to fill out up to two questionnaires +after each typing test which had to be linked to this specific typing test or +keyboard. With a total number of 24 subjects, five keyboards and therefore 10 +individual typing tests per subject or 240 typing tests in total, we decided to +incorporate a questionnaire feature into our platform to mitigate the +possibility of false mappings between typing tests, surveys and participants. Additionally, because we wanted to control the understandability of text without introducing observer bias for the text selection process and also to save time, we implemented a crowdsourcing feature where individuals @@ -34,7 +34,7 @@ as shown in Figure \ref{fig:s3_flow} \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 +team at Google \cite{golang}. The decision for Go was made because Go's standard library offers convenient packages to quickly setup a web server with simple routing and templating functionalities \cite{golang_std}. The backend and frontend communicate through a \gls{REST} \gls{API} and exchange data in @@ -144,7 +144,8 @@ KSPS = roundToPrecision((ISL - 1) / TEST_TIME, 5); % KSPC = roundToPrecision(ISL / TL, 5); For further implementation details on how input was captured or sent to the -backend refer to the code in the online repository \footnote{TODO: GITHUB}. +backend, refer to the code in the online +repository\footnote{\url{https://github.com/qhga/GoTT}}. To test the usability of the typing test, we asked five individuals to complete multiple typing tests with their own computer. Based on the feedback we @@ -209,7 +210,7 @@ not. The implementation of the algorithm that calculates the \gls{FRE} can be seen in Listing \ref{lst:gott_fre}. The function \textit{countSyllables} utilizes regex \footnote{\url{https://github.com/google/re2/wiki/Syntax}} matching to identify the number of syllables in a given string in German -language. The rules for hyphenation defined by Duden online +language. The rules for hyphenation defined by \textit{Duden Online} \footnote{\url{https://www.duden.de/sprachwissen/rechtschreibregeln/worttrennung}} were used to derive the regex patterns to identify syllables \cite{duden_hyphen}. The \gls{FRE} scores yielded by our function were verified @@ -276,7 +277,10 @@ func calculateFRE(txt string) float64 { \begin{figure}[ht] \centering \includegraphics[width=0.8\textwidth]{images/force_master_1} - \caption{Prototype of a measuring device that simulates the distance and finger position required to press different keys on a keyboard. The display shows the currently applied force in gram and the peak force applied throughout the current measurement in gram and \gls{N}} + \caption{Prototype of a measuring device that simulates the distance and + finger position required to press different keys on a keyboard. The display + shows the currently applied force in gram and the peak force applied + throughout the current measurement in gram and \gls{N}} \label{fig:force_master} \end{figure} @@ -300,7 +304,7 @@ applied force in gram and peak force in gram and \gls{N}. The devices was mainly controlled via two terminal commands. One command initiated re-calibration that was used after each participant or in between measurements and the other command reset all peak values displayed via the display. The base of the device featured -a scale, which was traversed with the help of a wrist wrest that got aligned +a scale, which was traversed with the help of a wrist rest that got aligned with the markings corresponding to the currently measured key. Each mark represents the distance and position of a finger to the associated key indicated by the label underneath the marking. The measurement process is explained in diff --git a/chap4/methodology.tex b/chap4/methodology.tex index e57708e..0952806 100644 --- a/chap4/methodology.tex +++ b/chap4/methodology.tex @@ -40,17 +40,17 @@ why we wanted to ascertain if and how, with the advance of technology in recent years and especially the capabilities modern smartphones offer, keyboard usage has changed. Further, we wanted to gather information about the preference of key resistance, keyswitch type and experiences with \gls{WRUED}. Therefore, we -conducted a structured interview with seventeen volunteers (59\% females) via +conducted a structured interview with seventeen volunteers (59\,\% females) via telephone, from which the most important results are presented in Figure \ref{fig:res_tel}. The age of the subjects ranged between 22 and 52 with a mean age of 29 years. The professions of subjects were distributed among medical workers, students, office employees, computer engineers and community workers. The first question we asked was \textit{``Which keyboard in terms of actuation force would be the most satisfying for you to use in the long - run?''}. Thirteen (76\%) out of the seventeen subjects mentioned, that they + run?''}. Thirteen (76\,\%) out of the seventeen subjects mentioned, that they would prefer a keyboard with light actuation force over a keyboard with higher resistance. The next question \textit{``Have you ever had pain when using a - keyboard and if so, where did you have pain?''} yielded, that 41\% of those + keyboard and if so, where did you have pain?''} yielded, that 41\,\% of those polled experienced pain at least once while using a keyboard. The areas affected described by the seven who already experienced pain were the wrist \underline{and} forearm (3 out of 7), wrist only (2 out of 7), fingers (1 out of @@ -68,7 +68,7 @@ durations related to computer work can be inaccurate prefer to perform with a keyboard rather than your mobile phone?''} revealed, that all of the subjects preferred to use a keyboard when entering greater amounts of data (emails, applications, presentations, calculations, research), -but also surprisingly 41\% preferred to use a keyboard to write instant messages +but also surprisingly 41\,\% preferred to use a keyboard to write instant messages (chatting via Whatsapp Web\footnote{\url{https://web.whatsapp.com/}}, Signal Desktop\footnote{\url{https://signal.org/download/}}, Telegram Desktop\footnote{\url{https://desktop.telegram.org/}}). @@ -90,14 +90,14 @@ Matias\footnote{\url{http://matias.ca/switches/}}, Razer\footnote{\url{https://www.razer.com/razer-mechanical-switches}} and Logitech\footnote{\url{https://www.logitechg.com/en-us/innovation/mechanical-switches.html}}. Since some of the key actuation forces listed on the manufacturers or resellers -websites were given in cN and most of them in g or gf, the values were adjusted -to gram to reflect a trend that is within a margin of ± 2 g of accuracy. The -results shown in Figure \ref{fig:keyswitches_brands} are used to determine the -minimum, maximum and most common actuation force for broadly available -keyswitches. According to our findings, the lowest commercially available -actuation force is 35 g ($\approx$ 0.34 \gls{N}) the most common one is 50 g -($\approx$ 0.49 \gls{N}) and the highest resistance available is 80 g ($\approx$ -0.78 \gls{N}). +websites were given in \gls{cN} and most of them in gram or gram-force, the values +were adjusted to gram to reflect a trend that is within a margin of ± 2\,g of +accuracy. The results shown in Figure \ref{fig:keyswitches_brands} are used to +determine the minimum, maximum and most common actuation force for broadly +available keyswitches. According to our findings, the lowest commercially +available actuation force is 35\,g ($\approx$ 0.34 \gls{N}) the most common one +is 50\,g ($\approx$ 0.49 \gls{N}) and the highest resistance available is 80\,g +($\approx$ 0.78 \gls{N}). \begin{figure}[H] \centering @@ -107,33 +107,35 @@ actuation force is 35 g ($\approx$ 0.34 \gls{N}) the most common one is 50 g \end{figure} \subsection{Preliminary Study of Finger Strength} -To evaluate the impact of an adjusted keyboard (keyboard with non-uniform -actuation forces) on performance and satisfaction we first needed to get an -understanding on how to distribute keyswitches with different actuation forces -across a keyboard. Our first idea was to use a similar approach to the keyboard -we described in Section \ref{sec:lr_sum}, were the force required to activate -the keys decreased towards the left and right ends of the keyboard. This rather -simple approach only accounts for the differences in finger strength when all -fingers are in the same position, but omits possible differences in applicable -force depending on the position a finger has to enter to press a certain key. -To detect possible differences in peak force depending on the position of the -fingers, we conducted an experiment with six volunteers (50\% -females). Subject's ages ranged from 20 to 26 with a mean age of 24 years. The -subjects were all personal contacts. Subjects professions were distributed as -follows: computer science students (3/6), physiotherapist (1/6), user experience -consultant (1/6) and retail (1/6). All Participants were given instructions to -exert maximum force for approximately one second onto the key mounted to the -measuring device described in Section \ref{sec:force_meas_dev}. We also used a -timer to announced when to press and when to stop. We provided a keyboard to -every participant, which was used as a reference for the finger position before -every measurement. To reduce order effects, we used a balanced latin square to -specify the sequence of rows (top, home, bottom) in which the participants had -to press the keys \cite{bradley_latin_square}. Additionally, because there were -only six people available, we alternated the direction from which participants -had to start in such a way, that every second subject started with the little -finger instead of the index finger. An example of four different positions of -the finger while performing the measurements for the keys \textit{Shift, L, I} -and \textit{Z} can be observed in Figure \ref{fig:FM_example}. +\label{sec:meth_force} +To evaluate the impact of an adjusted keyboard\footnote{keyboard with + non-uniform actuation forces} on performance and satisfaction we first needed +to get an understanding on how to distribute keyswitches with different +actuation forces across a keyboard. Our first idea was to use a similar approach +to the keyboard we described in Section \ref{sec:lr_sum}, were the force +required to activate the keys decreased towards the left and right ends of the +keyboard. This rather simple approach only accounts for the differences in +finger strength when all fingers are in the same position, but omits possible +differences in applicable force depending on the position a finger has to enter +to press a certain key. To detect possible differences in peak force depending +on the position of the fingers, we conducted an experiment with six volunteers +(50\,\% females). Subject's ages ranged from 20 to 26 with a mean age of 24 +years. The subjects were all personal contacts. Subjects professions were +distributed as follows: computer science students (3/6), physiotherapist (1/6), +user experience consultant (1/6) and retail (1/6). All Participants were given +instructions to exert maximum force for approximately one second onto the key +mounted to the measuring device described in Section +\ref{sec:force_meas_dev}. We also used a timer to announced when to press and +when to stop. We provided a keyboard to every participant, which was used as a +reference for the finger position before every measurement. To reduce order +effects, we used a balanced latin square to specify the sequence of rows (top, +home, bottom) in which the participants had to press the keys +\cite{bradley_latin_square}. Additionally, because there were only six people +available, we alternated the direction from which participants had to start in +such a way, that every second subject started with the little finger instead of +the index finger. An example of four different positions of the finger while +performing the measurements for the keys \textit{Shift, L, I} and \textit{Z} can +be observed in Figure \ref{fig:FM_example}. \begin{figure}[H] \centering @@ -148,7 +150,7 @@ and \textit{Z} can be observed in Figure \ref{fig:FM_example}. \end{figure} 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 +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 the adjusted keyboard. We used Eq. (\ref{eq:N_to_g}) and Eq. (\ref{eq:actuation_forces}) to calculate the theoretical gram values for @@ -156,7 +158,7 @@ each measured keyswitch. \begin{equation} \label{eq:N_to_g} - GFR = \frac{50 g}{M_{maf}} = \frac{50 g}{14.47 N} = 3.23 \frac{g}{N} + GFR = \frac{50\,g}{M_{maf}} = \frac{50\,g}{14.47\,N} = 3.23 \frac{g}{N} \end{equation} \begin{equation} @@ -164,7 +166,7 @@ each measured keyswitch. AF_{key} = GFR * MAF_{key} \end{equation} -With $M_{maf}$ the median of the means of applicable forces, $50 g$ the most +With $M_{maf}$ the median of the means of applicable forces, $50\,g$ the most commonly found actuation force on the market (Section \ref{sec:market_forces}), $GFR_{key}$ the gram to force ratio, $MAF_{key}$ the median of applicable force for a specific key and $AF_{key}$ the actuation force for that specific key in @@ -175,7 +177,7 @@ key can be seen in Eq. (\ref{eq:force_example}). \begin{equation} \label{eq:force_example} - AF_{P} = GFR * MAF_{P} = 3.23 \frac{g}{N} * 10.45 N \approx 33.75 g + AF_{P} = GFR * MAF_{P} = 3.23 \frac{g}{N} * 10.45\,N \approx 33.75\,g \end{equation} We then assigned the each theoretical actuation force to a group that resembles @@ -239,7 +241,7 @@ representing the best fit shown in Table \ref{tbl:force_groups}. \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 \\ + \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 @@ -314,14 +316,14 @@ 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 +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 +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 +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 @@ -345,7 +347,7 @@ throughout the experiment. 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 +measurements featured an Intel i7-5820K (12) @ 3.600\,GHz 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 @@ -381,11 +383,11 @@ corresponding actuation force can be found in Table \ref{tbl:kb_pseudo}. \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})\\ + \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.} @@ -457,8 +459,8 @@ was then confirmed, by observing the data received by the \textit{FlexVolt 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 +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 @@ -466,8 +468,8 @@ maximum possible force with their fingers (volar) against the top of the table (\gls{MVC} - flexion) and lastly, participants applied maximum possible force with their fingers (dorsal) 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 +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. A picture of all participants with the attached electrodes can be observed in Appendix \ref{app:emg}. @@ -477,13 +479,13 @@ 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 +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). +was repeated\footnote{Happened one time during the whole experiment}. \textbf{Texts Used for Typing Tests} @@ -508,7 +510,7 @@ 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}. -\textbf{Post Experiment Interview \& UX-Curves} +\textbf{Post Experiment Interview \& \Gls{UX Curve}s} To give participants the chance to recapitulate their experience during the whole experiment, we conducted a semi-structured interview, after all typing @@ -517,11 +519,11 @@ interviews and afterwards categorized common statements about each keyboard. Further, we prepared two different graphs were participants had to draw -UX-Curves related to subjectively perceived typing speed and subjectively +\Gls{UX Curve}s related to subjectively perceived typing speed and subjectively perceived fatigue for every keyboard and corresponding typing test. The graphs always reflected the order of keyboards for the group the current participant was part of. Furthermore, before the interview started, participants were given -a brief introduction on how to draw UX-Curves and that it is desirable to +a brief introduction on how to draw \Gls{UX Curve}s and that it is desirable to explain the thought process while drawing each curve \cite{kujala_ux_curve}. An example of the empty graph for perceived fatigue (group 1) can be seen in Figure \ref{fig:empty_ux_g1}. @@ -529,7 +531,7 @@ example of the empty graph for perceived fatigue (group 1) can be seen in Figure \begin{figure}[H] \centering \includegraphics[width=1.0\textwidth]{images/empty_ux_g1} - \caption{Empty graph for participants of group 1 to draw an UX-curve related + \caption{Empty graph for participants of group 1 to draw an \gls{UX Curve} related to perceived fatigue during the experiment} \label{fig:empty_ux_g1} \end{figure} @@ -538,8 +540,8 @@ example of the empty graph for perceived fatigue (group 1) can be seen in Figure Each subject had to take two, 5 minute, typing tests per keyboard, with a total of 5 keyboards, namely \textit{Own (participant's own keyboard)}, \textit{Nyx - (35 g, uniform), Aphrodite (50 g, uniform), Athena (80 g uniform)} and -\textit{Hera (35 g - 60 g, adjusted)} (Table \ref{tbl:kb_pseudo}). As described + (35\,g, uniform), Aphrodite (50\,g, uniform), Athena (80\,g uniform)} and +\textit{Hera (35\,g - 60\,g, adjusted)} (Table \ref{tbl:kb_pseudo}). As described in Section \ref{sec:main_keyboards}, the order of the keyboards \textit{Nyx, Aphrodite, Athena} and \textit{Hera} was counterbalanced with the help of a balanced latin square to reduce order effects. The keyboard \textit{Own} was @@ -566,4 +568,4 @@ necessary data for the design of the adjusted keyboard layout. Throughout the main user study, where we compared five different keyboards, we were able to obtain various qualitative and quantitative data regarding performance and satisfaction. The statistical evaluation of this data will be presented in the -next Section. +next sections. diff --git a/chap5/results.tex b/chap5/results.tex index 0a3b966..8a536a0 100644 --- a/chap5/results.tex +++ b/chap5/results.tex @@ -15,7 +15,7 @@ tests \cite{field_stats, downey_stats}. The reliability of the two sub-scales (hedonic and pragmatic quality) in the \glsfirst{UEQ-S} was estimated using \textit{Cronbach's alpha} \cite{tavakol_cronbachs_alpha}. All results are reported statistically significant with an $\alpha$-level of $p < 0.05$. We used -95\% confidence intervals when presenting certain results. Normality of data or +95\,\% confidence intervals when presenting certain results. Normality of data or residuals was checked using visual assessment of \gls{Q-Q} plots and additionally \textit{Shapiro-Wilk} Test. Further, we used \textit{Mauchly's Test for Sphericity} to evaluate if there was statistically significant variation @@ -95,13 +95,13 @@ can be observed in Table \ref{tbl:res_own_before_after}. We also evaluated the means of \glsfirst{KCQ} questions 8 to 12 which concerned perceived fatigue in fingers, wrists, arms, shoulders and neck respectively (7-point Likert scale) and the slopes (improving, deteriorating, stable) of the -UX-curves drawn by each participant after the whole experiment, to identify +\gls{UX Curve}s drawn by each participant after the whole experiment, to identify possible differences in perceived fatigue from T0\_1 to T0\_2. As shown in Figure \ref{fig:res_own_per_fat}, participants \gls{KCQ} reported slight improvements in terms of finger (diff = 0.33) and wrist (diff = 0.33) fatigue in T0\_2 compared to T0\_1, no difference in arm fatigue (diff = 0) and very slightly increased fatigue in shoulder (diff = -0.12) and neck (diff = -0.13) in -T0\_2 compared to T0\_1. Sixteen of the twenty-four UX-curves regarding overall +T0\_2 compared to T0\_1. Sixteen of the twenty-four \gls{UX Curve}s regarding overall perceived fatigue had positive slope when measured from start of T0\_1 to end of T0\_2 ($\pm$ 1 mm). The subjective reports about the decrease in finger and wrist fatigue emphasize the decrease in muscle activity for the flexor muscles @@ -112,7 +112,7 @@ we described in the last paragraph. \includegraphics[width=1.0\textwidth]{images/res_own_per_fat} \caption{Trends for reported fatigue through the \gls{KCQ} (questions 8: finger, 9: wrist, 10: arm, 11: shoulder, 12: neck) and histogram for the - slopes (IM: improving, DE: deteriorating, ST: stable) of UX-curves + slopes (IM: improving, DE: deteriorating, ST: stable) of \gls{UX Curve}s concerning perceived fatigue. The curves were evaluated by looking at the y value of the starting point for T0\_1 and comparing it to y value of the end point for T0\_2 with a margin of $\pm$ 1 mm} @@ -144,12 +144,12 @@ relevant results of the post-hoc tests and the summary of the performance data can be observed in Tables \ref{tbl:sum_tkbs_speed} and \ref{tbl:res_tkbs_speed}. We further examined, which of the four test keyboard was the fastest for each participant and found, that \textit{Hera} was the -fastest keyboard in terms of \gls{WPM} for 46\% (11) of the twenty-four +fastest keyboard in terms of \gls{WPM} for 46\,\% (11) of the twenty-four subjects. Additionally, we analyzed the \gls{WPM} percentage of \textit{Own} (\gls{OPC}) for all test keyboards to figure out, which keyboard exceeded the performance of the participant's own keyboard. We found, that three subjects -reached \gls{OPC}\_\gls{WPM} values greater than 100\% with all four test -keyboards. Also, \textit{Athena, Aphrodite} and \textit{Hera} exceeded 100\% of +reached \gls{OPC}\_\gls{WPM} values greater than 100\,\% with all four test +keyboards. Also, \textit{Athena, Aphrodite} and \textit{Hera} exceeded 100\,\% of \gls{OPC}\_\gls{WPM} eight, seven and six times respectively. Detailed results are presented in Figure \ref{fig:max_opc_wpm}. @@ -230,7 +230,7 @@ are presented in Figure \ref{fig:max_opc_wpm}. \includegraphics[width=1.0\textwidth]{images/max_opc_wpm} \caption{The left graph shows the fastest keyboard in terms of \gls{WPM} for each participant. The right graph shows, which keyboards were even faster - than the participant's own keyboard (\gls{OPC}\_\gls{WPM} > 100\%)} + than the participant's own keyboard (\gls{OPC}\_\gls{WPM} > 100\,\%)} \label{fig:max_opc_wpm} \end{figure} @@ -247,7 +247,7 @@ conduct the analysis. The Friedman's Tests for \gls{TER} ($\chi^2$(3) = 25.4, p (\gls{GG})) revealed differences for at least two test keyboards. The Friedman's Test for \gls{UER} ($\chi^2$(3) = 2.59, p = 0.46) yielded no statistical significant difference. It should be noted, that the 90th percentile of -\gls{UER} for all keyboards was still below 1\%. Summaries for the individual +\gls{UER} for all keyboards was still below 1\,\%. Summaries for the individual metrics and results for all post-hoc tests can be seen in Table \ref{tbl:sum_tkbs_err} and \ref{tbl:res_tkbs_err}. Furthermore, we compared the \gls{TER} of all test keyboards for each participant and found, that @@ -341,7 +341,7 @@ to \textit{Own} (\gls{OPC}). All data can be observed in Figure \includegraphics[width=1.0\textwidth]{images/max_opc_ter} \caption{The left graph shows the keyboard with the lowest \gls{TER} for each participant. The right graph shows, which keyboards were more accurate than - the participant's own keyboard (\gls{OPC}\_\gls{TER} < 100\%)} + the participant's own keyboard (\gls{OPC}\_\gls{TER} < 100\,\%)} \label{fig:max_opc_ter} \end{figure} @@ -366,11 +366,11 @@ test keyboards of the mean values for both typing tests combined can be observed in Table \ref{tbl:sum_tkbs_emg}. Lastly, we created histograms (Figure \ref{fig:max_emg_tkbs}) for each of the observed muscle groups, that show the number of times a keyboard yielded the highest \%\gls{MVC} out of all keyboards -for each participant. We found, that \textit{Athena} most frequently ($\approx$45\%) +for each participant. We found, that \textit{Athena} most frequently ($\approx$45\,\%) produced the highest extensor muscle activity for both arms. The highest muscle activity for both flexor muscle groups was evenly distributed among all test keyboards with a slight exception of \textit{Nyx}, which produced the highest -\%\gls{MVC} only in ~14\% of participants. +\%\gls{MVC} only in ~14\,\% of participants. \begin{figure}[H] \centering @@ -518,7 +518,7 @@ Table \ref{tbl:res_kcq}. \end{table} \subsubsection{User Experience Questionnaire (Short)} \label{sec:res_ueqs} -Additionally to the \gls{KCQ} we utilized the \glsfirst{UEQ-S}. It featured +In addition to to the \gls{KCQ}, we utilized the \glsfirst{UEQ-S}. It featured eight questions on a 7-point Likert scale, which formed two scales (pragmatic, hedonic). Additionally we added one extra question that could be answered on a \glsfirst{VAS} from 0 to 100. The survey was filled out after both tests with a @@ -596,7 +596,7 @@ observed in Tables \ref{tbl:res_tkbs_sati} and \ref{tbl:sum_tkbs_sati}. towards significance are denoted with $\dagger$. Confidence intervals are given for the difference of the location parameter. We only tested keyboards with lower actuation force against keyboards with higher actuation - force. The first comparison of Aphrodite (50 g) and Nyx (35 g) was added, + force. The first comparison of Aphrodite (50\,g) and Nyx (35\,g) was added, because of the noticeable differences in the visual assessment of Figure \ref{fig:res_tkbs_sati}} \label{tbl:res_tkbs_sati} @@ -637,7 +637,7 @@ observed in Tables \ref{tbl:res_tkbs_sati} and \ref{tbl:sum_tkbs_sati}. \label{sec:res_uxc} In order to give all participants the chance to recapitulate the whole experiment and give retrospective feedback about each individual keyboard, we -conducted a semi-structured interview which included drawing UX-curves for +conducted a semi-structured interview which included drawing \gls{UX Curve}s for perceived fatigue and perceived typing speed. We evaluated the curves by measuring the y position of the \gls{SP} for a curve and the y position of the respective \gls{EP} an determine the slope of that curve. Slopes are defined as @@ -655,7 +655,7 @@ participants own keyboard was four times more often placed first than any other keyboard. \textit{Hera} was the only keyboard, that never got placed fifth and except for \textit{Own}, was the most represented keyboard in the top three. The ranking of the perceived actuation force revealed, that participants were able -to identify \textit{Nyx} (35 g) and \textit{Athena} (80 g) as the keyboards with +to identify \textit{Nyx} (35\,g) and \textit{Athena} (80\,g) as the keyboards with the lowest and highest actuation force respectively. All results for both rankings are visualized in Figure \ref{fig:res_interview}. Lastly, we analyzed the recordings of all interviews and found several similar statements about @@ -674,7 +674,7 @@ which could be related to a comment of two subjects―\textit{``It felt very \begin{figure}[H] \centering \includegraphics[width=1.0\textwidth]{images/res_uxc} - \caption{\centering Evaluation of UX-curve slopes for perceived fatigue and perceived + \caption{\centering Evaluation of \gls{UX Curve} slopes for perceived fatigue and perceived speed. \\ \textit{DE:} deteriorating, \textit{IM:} improving, \textit{ST:} stable} \label{fig:res_uxc} diff --git a/chap6/discussion.tex b/chap6/discussion.tex index 077edd8..28e5c25 100644 --- a/chap6/discussion.tex +++ b/chap6/discussion.tex @@ -12,19 +12,19 @@ question \textit{``Does an adjusted actuation force per key have a positive Our main experiment yielded, that there are differences in typing speed for both metrics related to transcribed text we measured―namely \glsfirst{WPM} and \glsfirst{AdjWPM}. Especially the keyboard with the lowest uniform actuation -force of 35 g―\textit{Nyx}―performed worse than all other keyboards. In terms of -\gls{WPM}, \textit{Nyx (35 g)} was on average 4.1\% slower than \textit{Athena - (80 g)} and \textit{Aphrodite (50 g)} and 4.8\% slower than the adjusted -keyboard \textit{Hera (35 - 60 g)}. Similarly, for \gls{AdjWPM}, \textit{Nyx} -was 4.3\% slower than \textit{Athena} and \textit{Aphrodite} and 4.9\% slower -than \textit{Hera}. The 4\% to 5\% difference in \gls{WPM} and \gls{AdjWPM} in -our sample account for approximately 2 words per minute. When extrapolated with -the mean daily keyboard usage of 6.69 hours reported by our participants, this -difference would be as big as 803 words, which when put into perspective, is -equivalent to roughly two full pages of only written content (11pt font -size). Although, this specific example would assume constant typing for 6.69 -hours, it is still a useful estimate of the loss in productivity under normal -working conditions over the course of several days. These differences in +force of 35\,g―\textit{Nyx}―performed worse than all other keyboards. In terms +of \gls{WPM}, \textit{Nyx (35\,g)} was on average 4.1\,\% slower than +\textit{Athena (80\,g)} and \textit{Aphrodite (50\,g)} and 4.8\,\% slower than the +adjusted keyboard \textit{Hera (35 - 60\,g)}. Similarly, for \gls{AdjWPM}, +\textit{Nyx} was 4.3\,\% slower than \textit{Athena} and \textit{Aphrodite} and +4.9\,\% slower than \textit{Hera}. The 4\,\% to 5\,\% difference in \gls{WPM} and +\gls{AdjWPM} in our sample account for approximately 2 words per minute. When +extrapolated with the mean daily keyboard usage of 6.69 hours reported by our +participants, this difference would be as big as 803 words, which when put into +perspective, is equivalent to roughly two full pages of only written content +(11pt font size). Although, this specific example would assume constant typing +for 6.69 hours, it is still a useful estimate of the loss in productivity under +normal working conditions over the course of several days. These differences in \gls{WPM} and \gls{AdjWPM} could be explained by the higher error rates and thereby the loss of ``typing flow'' we discuss in the next section. \gls{KSPS} reflects the raw input speed by including backspaces and previously deleted @@ -32,10 +32,10 @@ characters. The reason we included \gls{KSPS} in our analysis was to reveal possible differences in the physical speed participants type on a keyboard and not to further asses speed in the sense of productivity. We could not find any statistically significant differences in \gls{KSPS} but saw a trend, indicating -that subjects typed a bit slower (< 3\%) on \textit{Athena (80 g)} compared to -\textit{Aphrodite (50 g)} and \textit{Hera (35 - 60 g)}. With the differences in -metrics that are commonly used to measure typing speed more closely related to -productivity (\gls{WPM}, \gls{AdjWPM}) and the trends that indicate a slight +that subjects typed a bit slower (< 3\,\%) on \textit{Athena (80\,g)} compared to +\textit{Aphrodite (50\,g)} and \textit{Hera (35 - 60\,g)}. With the differences +in metrics that are commonly used to measure typing speed more closely related +to productivity (\gls{WPM}, \gls{AdjWPM}) and the trends that indicate a slight difference in operating speed we could have accepted our hypothesis. However, with the relation between error rate and typing speed described in the next section and the thereby rather indirect effect of the actuation force, we can @@ -46,7 +46,7 @@ force, has an impact on typing speed. Actuation force has an impact on typing speed (efficiency - speed). \end{phga_hyp*} -% During our telephone interviews 76\% of respondents would have preferred a +% During our telephone interviews 76\,\% of respondents would have preferred a % keyboard with lighter actuation force. % Our study tried to present the participant with a typing scenario that is as @@ -58,16 +58,16 @@ force, has an impact on typing speed. As already briefly mentioned in Section \ref{sec:dis_speed}, measured error rates like \glsfirst{UER}, \glsfirst{CER} and \glsfirst{TER} differed especially -between \textit{Nyx (35 g)} and the other test keyboards. The statistical +between \textit{Nyx (35\,g)} and the other test keyboards. The statistical analyses further revealed, that \textit{Athena}, the keyboard with the highest -actuation force of 80 g, produced on average 1\% less \gls{TER} than -\textit{Hera (35 - 60 g)} and \textit{Aphrodite (50 g)} and 3\% less than -\textit{Nyx (35g)}. Furthermore, \textit{Hera} and \textit{Aphrodite} both had a -2\% lower \gls{TER} than \textit{Nyx}. Additionally to the quantitative results, +actuation force of 80\,g, produced on average 1\,\% less \gls{TER} than +\textit{Hera (35 - 60\,g)} and \textit{Aphrodite (50\,g)} and 3\,\% less than +\textit{Nyx (35\,g)}. Furthermore, \textit{Hera} and \textit{Aphrodite} both had a +2\,\% lower \gls{TER} than \textit{Nyx}. Additionally to the quantitative results, fourteen of the twenty-four participants also reported, that \textit{Nyx's} light actuation force was the reason for many accidental key presses. It further stood out, that as shown in Figure \ref{fig:max_opc_ter}, \textit{Athena} was -the most accurate keyboard for 58\% of participants and also more accurate than +the most accurate keyboard for 58\,\% of participants and also more accurate than keyboard \textit{Own} for eleven of the subjects. Overall, this concludes, that a higher actuation force has a positive impact on error rate. @@ -131,7 +131,7 @@ significant differences for any of the test keyboards regarding the pragmatic scale of the \gls{UEQ-S}. From visual assessment of the graph shown in Figure \ref{fig:ueq_tkbs_res} we could conclude, that there is a slight trend towards a more positive rating for keyboards that utilized keyswitches with higher -actuation forces than \textit{Nyx (35 g)}. This trend in the opposite direction +actuation forces than \textit{Nyx (35\,g)}. This trend in the opposite direction of our hypothesized outcome, that lighter actuation force leads to more user satisfaction, could be due to the longer familiarization time required for keyboards with very light actuation force \cite{gerard_keyswitch}. @@ -141,10 +141,10 @@ keyboards with very light actuation force \cite{gerard_keyswitch}. The results deduced from the additional question \textit{``How satisfied have you been with this keyboard?''}, which could be answered on a \glsfirst{VAS} from 0 to 100 after both tying tests with a keyboard, suggested that \textit{Nyx - (35 g)}, the keyboard with the lightest actuation force and also -\textit{Athena (80 g)} the keyboard with the highest actuation force, were rated -significantly worse than \textit{Aphrodite (50 g)}. Additionally, \textit{Hera - (35 - 60 g)}, the adjusted keyboard showed a trend towards a significantly + (35\,g)}, the keyboard with the lightest actuation force and also +\textit{Athena (80\,g)} the keyboard with the highest actuation force, were rated +significantly worse than \textit{Aphrodite (50\,g)}. Additionally, \textit{Hera + (35 - 60\,g)}, the adjusted keyboard showed a trend towards a significantly better rating than \textit{Nyx}. These results indicate, that neither of the keyboards with extreme actuation forces were perceived as a overwhelmingly pleasant keyboard to use during our typing tests. This is further supported by @@ -156,15 +156,15 @@ the average ratings for \textit{Aphrodite} and \textit{Hera} were approximately For the \gls{KCQ} we found several statistically significant differences. For questions related to effort or fatigue while operating a keyboard, -\textit{Athena (80 g)} received significantly lower ratings than the other test +\textit{Athena (80\,g)} received significantly lower ratings than the other test keyboards. Additionally to the measured differences in error rates discussed in Section \ref{sec:dis_error}, we discovered that participants also perceived the -accuracy of \textit{Athena (80 g)} and \textit{Aphrodite (50 g)} higher compared -to \textit{Nyx (35 g)}. Similarly to the results discussed in the last +accuracy of \textit{Athena (80\,g)} and \textit{Aphrodite (50\,g)} higher compared +to \textit{Nyx (35\,g)}. Similarly to the results discussed in the last paragraph, the scores of the two keyboards with extreme actuation forces, -\textit{Nyx (35 g)} and \textit{Athena (80 g)} fluctuated quite a bit and on -average those two keyboards scored lower than \textit{Aphrodite (50 g)} or -\textit{Hera (35 - 60 g)} (Figure \ref{fig:kcq_tkbs_res}). Thereby, these +\textit{Nyx (35\,g)} and \textit{Athena (80\,g)} fluctuated quite a bit and on +average those two keyboards scored lower than \textit{Aphrodite (50\,g)} or +\textit{Hera (35 - 60\,g)} (Figure \ref{fig:kcq_tkbs_res}). Thereby, these results do not indicate a clear trend towards enhanced user experience when using keyboards with lower actuation forces. @@ -194,7 +194,7 @@ Figure \ref{fig:ratio_interview}, to evaluate preferences towards specific keyboards, that could not be expressed by our participants through any other supplied method during the experiment. Like all other factors we identified as reasonable indicators for satisfaction, these ratios yielded, that neither -\textit{Athena (80 g)} nor \textit{Nyx (35 g)} received more positive than +\textit{Athena (80\,g)} nor \textit{Nyx (35\,g)} received more positive than negative feedback. It should be noted, that previous research has shown that people tend to remember and process bad experiences more thorough than good ones, which could be a reason for the increased number of negative feedback for @@ -211,13 +211,13 @@ those two keyboards \cite{baumeister_bad}. \textbf{Conclusion} -Contrary to the responses of our preliminary telephone interview, where 76\% of +Contrary to the responses of our preliminary telephone interview, where 76\,\% of attendees preferred a keyboard with light actuation force, none of the factors we defined as relevant for user satisfaction suggests, that keyboards with lower actuation force are more satisfactory to use than keyboards with higher actuation force. Therefore, we have to fully reject our hypothesis. We can conclude thought, that keyboards with actuation forces in between those two -extremes (35 g / 80 g), are persistently perceived as more pleasant to use and +extremes (35\,g / 80\,g), are persistently perceived as more pleasant to use and that ratings keyboards with extreme actuation forces are highly influenced by personal preference, which is indicated by the high fluctuation of almost all responses regarding our evaluated factors. @@ -232,7 +232,7 @@ responses regarding our evaluated factors. In contrast to other studies that suggested, that actuation force has an impact on muscle activity, we could not identify significant differences in terms of \% of \glsfirst{MVC} for any of our \gls{EMG} measurements. Only a slight trend, -that \textit{Nyx (35 g)} produced the highest flexor \%\gls{MVC} for only 14\% +that \textit{Nyx (35\,g)} produced the highest flexor \%\gls{MVC} for only 14\,\% of participants, could be interpreted as anecdotal evidence towards our hypothesis, that actuation force has an impact on muscle activity. Therefore we have to reject our hypothesis. @@ -256,7 +256,7 @@ perceived as equivalent to the participant's own keyboard. In fact, \textit{Hera} was the keyboard with the most occurrences in the top three, tied first place with \textit{Aphrodite} and was never ranked 4th place during the post-experiment interview (Figure \ref{fig:tkbs_ranking}). Since \textit{Hera}, -among others, utilized keyswitches with light actuation force (35 g), the +among others, utilized keyswitches with light actuation force (35\,g), the satisfaction could improve during prolonged usage, because of the longer familiarization period required by keyboards with lighter actuation forces \cite{gerard_keyswitch}. Interestingly, participant \textit{I3Z4XI7H} who @@ -274,16 +274,16 @@ that an adjusted keyboard is more satisfactory to use than standard keyboards. to standard keyboards. \end{phga_hyp*} -Similarly, the resulting error rates measured for \textit{Hera (35 - 60 g)} were -close to equal to the results of \textit{Aphrodite (50 g)} and for speed related +Similarly, the resulting error rates measured for \textit{Hera (35 - 60\,g)} were +close to equal to the results of \textit{Aphrodite (50\,g)} and for speed related metrics between those two keyboards only slight improvements while using -\textit{Hera} in \gls{WPM} (0.8\%), \gls{AdjWPM} (0.6\%) and \gls{KSPS} (1\%)― +\textit{Hera} in \gls{WPM} (0.8\,\%), \gls{AdjWPM} (0.6\,\%) and \gls{KSPS} (1\,\%)― that were not statistically significant―were recorded during our experiment. It was still interesting to see, that \textit{Hera} was the fastest, out of all -four test keyboards, for eleven (45\%) out of the twenty-four subjects and that -albeit the usage of 30\% keyswitches\footnote{That were actually pressed during - our typing tests} that required 35 - 40 g actuation force, which is similar to -the actuation force of \textit{Nyx (35 g)}, we did not see comparably high error +four test keyboards, for eleven (45\,\%) out of the twenty-four subjects and that +albeit the usage of 30\,\% keyswitches\footnote{That were actually pressed during + our typing tests} that required 35 - 40\,g actuation force, which is similar to +the actuation force of \textit{Nyx (35\,g)}, we did not see comparably high error rates. Because of the lacking evidence, that an adjusted keyboard produces less errors or supports the typist in achieving higher typing speeds, we have to reject our two hypotheses regarding those improvements. @@ -299,7 +299,7 @@ reject our two hypotheses regarding those improvements. \end{phga_hyp*} Our experiment basically revealed, that keyboards which utilized keyswitches -with actuation forces that were neither to light (35 g) nor to heavy (80 g), +with actuation forces that were neither too light (35\,g) nor too heavy (80\,g), generally outperformed keyboards which featured those extreme actuation forces. In the following section, we elaborate on possible limitations of our experimental design and future research that could be reasonable to further diff --git a/chap7/conclusion.tex b/chap7/conclusion.tex index 6baa6c8..78cd317 100644 --- a/chap7/conclusion.tex +++ b/chap7/conclusion.tex @@ -13,7 +13,7 @@ on typing speed, error rate and satisfaction revealed, that higher actuation forces reduce error rates compared to lower actuation forces and that the typing speed is also influenced, \textbf{at least indirectly}, by differences in actuation force. Especially the keyboard with very low actuation force, -\textit{Nyx (35 g)}, which also had the highest average error rate was +\textit{Nyx (35\,g)}, which also had the highest average error rate was significantly slower than all other keyboards. Therefore, we investigated, if there is a connection between high error rates and stagnating typing speed and found, that in general, the error rate was a factor for lower input @@ -21,16 +21,16 @@ rates. Neither the satisfaction nor the muscle activity was significantly influenced solely by the actuation. In conclusion, our study showed, that the keyboard with non-uniform actuation -forces―\textit{Hera (35 - 60 g)}―was not able to improve the overall typing +forces―\textit{Hera (35 - 60\,g)}―was not able to improve the overall typing experience significantly enough to supersede existing designs, but was still a viable alternative to all traditional keyboards we tested. It could be possible, -that due to the unconventional force distribution, that similar to keyboards +that due to the unconventional force distribution, that is similar to keyboards with very light actuation force, the muscle activity while using \textit{Hera} could decrease when users are given more time to adapt to this keyboard \cite{gerard_keyswitch}. Additionally, we found that keyboards with either very -high (80 g) or very low (35 g) actuation forces had the most influence on typing +high (80\,g) or very low (35\,g) actuation forces had the most influence on typing related metrics, when compared to the more commonly sold keyboards with around -50 g to 60 g actuation force. In the next sections we identify possible +50\,g to 60\,g actuation force. In the next sections we identify possible limitations and propose some ideas on how to reevaluate custom keyboard designs in future studies. @@ -45,7 +45,7 @@ the researcher was in the same room, the limited time for the individual typing tests and the rather short breaks in between typing tests, could have influenced some subjects by inducing unnecessary stress. Another limitation related to the preliminary finger strength study, was the very small number of participants (n -= 6). Although we measured the finger strengths in different positions for 50\% += 6). Although we measured the finger strengths in different positions for 50\,\% female and male participants, the age distribution was not diverse (M = 24) and with a higher number of subjects, the results would have been much more reliable. Similarly, the number and diversity in occupation of participants @@ -62,8 +62,8 @@ We propose, that in further research related to keyboards with non-uniform actuation force (adjusted keyboards), participants should test several different adjusted keyboards and the results should be compared to one identical looking keyboard that utilizes a uniform layout of keyswitches with an actuation force -of 50 g to 65 g. Further, different adjusted layouts, with e.g. higher or lower -base actuation force than 50 g could be used to calculate the individual spring +of 50\,g to 65\,g. Further, different adjusted layouts, with e.g. higher or lower +base actuation force than 50\,g could be used to calculate the individual spring resistances used for each key or a similar layout to the one used in Realforce\footnote{\url{https://www.realforce.co.jp/en/products/}} keyboards, could be compared to each other. Furthermore, long term studies with adjusted diff --git a/glossary.tex b/glossary.tex index e8f9f2e..ad2b162 100644 --- a/glossary.tex +++ b/glossary.tex @@ -5,9 +5,11 @@ \newacronym{MVC}{MVC}{maximum voluntary contraction} \newacronym{CTS}{CTS}{Carpal Tunnel Syndrome} \newacronym{RSI}{RSI}{Repetitive Strain Injury} +\newacronym{TNS}{TNS}{Tension Neck Syndrome} \newacronym{FRE}{FRE}{Flesch Reading Ease Score} \newacronym{VAS}{VAS}{visual analog scale} \newacronym{RMS}{RMS}{root-mean-square} +\newacronym{ISO}{ISO}{International Organization for Standardization} % Mulcles alive p. 189 % Atlas of Human Anatomy p. 433 \newacronym{FDS}{FDS}{flexor digitorum superficialis} @@ -45,25 +47,22 @@ \newacronym{EP}{EP}{end point} \newacronym{LRT}{LRT}{Likelihood Ratio Test} - - - \newglossaryentry{N}{ name={N}, -description={Newton: 1 N $ \approx $ 101.97 g} +description={Newton: 1\,N $ \approx $ 101.97\,g} } \newglossaryentry{cN}{ name={cN}, -description={Centinewton: 1 cN $ \approx $ 1.02 g} +description={Centinewton: 1\,cN $ \approx $ 1.02\,g} } \newglossaryentry{g}{ name={g}, -description={Gram: 1 g $ \approx $ 0.97 cN} +description={Gram: 1\,g $ \approx $ 0.97\,cN} } \newglossaryentry{gf}{ name={gf}, -description={Gram-force: 1 gf = 1 g} +description={Gram-force: 1\,gf = 1\,g} } \newglossaryentry{QWERTY}{ name={QWERTY}, @@ -76,7 +75,13 @@ description={Keyboard layout commonly used in Germany} \newglossaryentry{bottoming}{ name={bottoming out}, -description={Describes the scenario when the typist does not release the key before impact with the bottom of the keyswitch is made} +description={Describes the scenario, when the typist does not release the key before impact with the bottom of the keyswitch is made} +} + +\newglossaryentry{swapped}{ +name={hot-swapped}, +description={Usually describes the process of replacing a part of a device in a + quick an simple way, without the need to power off the device} } \newglossaryentry{Topre}{ @@ -87,4 +92,11 @@ description={Topre switches are keyswitches produced by the Japanese company Top \newglossaryentry{MongoDB}{ name={MongoDB}, description={General purpose, document-based database which name originates from the word humongous} -} \ No newline at end of file +} + +\newglossaryentry{UX Curve}{ + name={UX Curve}, + description={A User Experience + Curve is used to assess long-term user experience for a product. Users draw + a curve, that represents a certain experience, positive, neutral or negative, for + a specific product during a time span} } diff --git a/images/keyboards.jpg b/images/keyboards.jpg new file mode 100644 index 0000000..c09f988 Binary files /dev/null and b/images/keyboards.jpg differ diff --git a/images/keyboards.jpg~ b/images/keyboards.jpg~ new file mode 100644 index 0000000..12e7343 Binary files /dev/null and b/images/keyboards.jpg~ differ diff --git a/images/res_own_per_fat.png b/images/res_own_per_fat.png index 005c771..7c7a34a 100644 Binary files a/images/res_own_per_fat.png and b/images/res_own_per_fat.png differ diff --git a/images/ux_curve_results.jpg b/images/ux_curve_results.jpg index 2deb13b..0268511 100644 Binary files a/images/ux_curve_results.jpg and b/images/ux_curve_results.jpg differ