diff --git a/chap4/methodology.tex b/chap4/methodology.tex index 9013d2b..ba0da1a 100644 --- a/chap4/methodology.tex +++ b/chap4/methodology.tex @@ -272,13 +272,13 @@ keyboard?.''} \\ & \textbf{H3} & Keys with lower actuation force are perceived as more satisfactory to type with than keys with higher actuation force. & \\ \\ - & \textbf{H4} & An adjusted keyboard (non-uniform actuation forces) improves typing speed compared to standard keyboards (uniform actuation forces) (efficiency - speed).& \\ + & \textbf{H4} & Differences in actuation force influence muscle activity while typing. & \\ \\ - & \textbf{H5} & An adjusted keyboard decreases typing errors compared to standard keyboards (efficiency - error rate).& \\ + & \textbf{H5} & An adjusted keyboard (non-uniform actuation forces) improves typing speed compared to standard keyboards (uniform actuation forces) (efficiency - speed).& \\ \\ - & \textbf{H6} & An adjusted keyboard is perceived as more satisfactory to type with compared to standard keyboards. & \\ + & \textbf{H6} & An adjusted keyboard decreases typing errors compared to standard keyboards (efficiency - error rate).& \\ \\ - & \textbf{H7} & Differences in actuation force influence muscle activity while typing. & \\ + & \textbf{H7} & An adjusted keyboard is perceived as more satisfactory to type with compared to standard keyboards. & \\ \end{longtable} \subsubsection{Method} diff --git a/chap5/results.tex b/chap5/results.tex index a734324..0a3b966 100644 --- a/chap5/results.tex +++ b/chap5/results.tex @@ -553,7 +553,7 @@ right term of the ``or'' questions. All sub-scales, pragmatic ($\alpha$ = for Cronbach's alpha of $\alpha$ > 0.7 \cite{schrepp_ueq_handbook}. The mean values for all responses of the \gls{UEQ-S} can be seen in Figure \ref{fig:kcq_tkbs_res} and the individual responses to the additional question -(SATI) are presented in Figure \ref{fig:sati_tkbs_res}. We conducted +(SATI) are presented in Figure \ref{fig:res_tkbs_sati}. We conducted \gls{rmANOVA}s for both sub-scales but found no statistically significant variations for the pragmatic scale (F(3, 69) = 3.254, p = 0.06, post-hoc did not reveal any tendencies) nor the hedonic scale (F(3, 69) = 0.425, p = @@ -598,7 +598,7 @@ observed in Tables \ref{tbl:res_tkbs_sati} and \ref{tbl:sum_tkbs_sati}. with lower actuation force against keyboards with higher actuation 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:sati_tkbs_res}} + \ref{fig:res_tkbs_sati}} \label{tbl:res_tkbs_sati} \end{table} @@ -629,7 +629,7 @@ observed in Tables \ref{tbl:res_tkbs_sati} and \ref{tbl:sum_tkbs_sati}. \caption{Responses for the additional question \textit{``How satisfied have you been with this keyboard?''} with the means for all participant represented as horizontal lines} - \label{fig:sati_tkbs_res} + \label{fig:res_tkbs_sati} \end{figure} diff --git a/chap6/discussion.tex b/chap6/discussion.tex index 621689b..9a578f5 100644 --- a/chap6/discussion.tex +++ b/chap6/discussion.tex @@ -36,12 +36,12 @@ 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 can accept our hypothesis that solely a -difference in actuation force has an impact on typing speed. +difference in operating speed, we can accept our hypothesis that a difference in +actuation force, at least indirectly, has an impact on typing speed. -\begin{phga_hyp}[\checkmark] +\begin{phga_hyp*}[1 $\rightarrow$ \cmark] Actuation force has an impact on typing speed (efficiency - speed). -\end{phga_hyp} +\end{phga_hyp*} % During our telephone interviews 76\% of respondents would have preferred a % keyboard with lighter actuation force. @@ -65,13 +65,13 @@ 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 -keyboard \textit{Own} for eleven of the subjects. This concludes, that a higher -actuation force has a positive impact on error rate. +keyboard \textit{Own} for eleven of the subjects. Overall, this concludes, that +a higher actuation force has a positive impact on error rate. -\begin{phga_hyp}[\checkmark] +\begin{phga_hyp*}[2 $\rightarrow$ \cmark] Higher key actuation force decreases typing errors compared to lower key actuation force (efficiency - error rate). -\end{phga_hyp} +\end{phga_hyp*} \textbf{Impact of \gls{TER} on \gls{WPM}} @@ -81,19 +81,190 @@ this additional relation, we conducted a \gls{LRT} of fixed effects for our linear mixed-effects model with two random effects (participant and first/second typing test), fixed effect \gls{TER} and response variable \gls{WPM}. The results of the \gls{LRT} ($\chi^2(1)$ = 110.44, p = 0.00000000000000022) -suggest, that the \gls{TER} indeed had an impact on \gls{WPM}. This could have -been, because every time an error was made, almost all participants decided to -correct it right away. With a higher error rate, this obviously leads to many -short interruptions and an increased number of characters that are not taken -into account when computing the \gls{WPM} metric. +together with the trends of lower \gls{WPM} with increasing \gls{TER}, visible +in Figure \ref{fig:reg_ter_wpm}, suggest, that the \gls{TER} indeed had an +impact on \gls{WPM}. This could have been, because every time an error was made, +almost all participants decided to correct it right away. With a higher error +rate, this obviously leads to many short interruptions and an increased number +of characters that are not taken into account when computing the \gls{WPM} +metric. +\begin{figure}[H] + \centering + \includegraphics[width=1.0\textwidth]{images/reg_ter_wpm} + \caption{Regression lines for the relation between \gls{TER} and \gls{WPM}. + The trends indicate a decrease in \gls{WPM} with rising \gls{TER} and + therefore the existence of a relation between the two metrics} + \label{fig:reg_ter_wpm} +\end{figure} \subsection{Impact of Actuation Force on Satisfaction} \label{sec:dis_sati} +We tried to narrow down the rather broad term ``satisfaction'' to individual +categories that we, with the information gathered through our literature review +and telephone interviews, defined as necessary for a positive user experience +while using a keyboard \cite{giese_sati}. We decided for the following metrics +to evaluate, whether or not a user experience with a keyboard that features +lighter actuation forces was more satisfactory: + +\begin{table}[H] + \centering + \ra{1.0} + \small + \begin{tabular}{l} + $\rightarrow$ Pragmatic scale from the \glsfirst{UEQ-S} \\ + $\rightarrow$ Score of the additional question \textit{``How satisfied have you been with this keyboard?''}\\ + $\rightarrow$ Results of the \glsfirst{KCQ}\\ + $\rightarrow$ Ranking of the keyboards during semi-structured interview\\ + $\rightarrow$ Ratio of positive and negative feedback for each keyboard during semi-structured interview\\ + \end{tabular} +\end{table} + +\textbf{[\xmark] Pragmatic Scale (\gls{UEQ-S})} + +As described in Section \ref{sec:res_ueqs}, we could not find statistically +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 +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}. + +\textbf{[\xmark] Additional Question of Satisfaction with Keyboard} + +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 +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 +the visualisation of the mean ratings in Figure \ref{fig:res_tkbs_sati} where +the average ratings for \textit{Aphrodite} and \textit{Hera} were approximately +10 points higher than those for \textit{Nyx} and \textit{Athena}. + +\textbf{[\xmark] Keyboard Comfort Questionnaire (\gls{KCQ})} + +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 +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 +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 +results do not indicate a clear trend towards enhanced user experience when +using keyboards with lower actuation forces. + +\textbf{[\xmark] Post Experiment Ranking of All Keyboards} + +The ranks in terms of favored test keyboard, provided by all twenty-four +participants during the post-experiment semi-structured interview, can be +observed in Figure \ref{fig:tkbs_ranking}. The results further support the +tendencies towards keyboards with medium actuation forces, that we already +observed in the last couple paragraphs. + +\begin{figure}[H] + \centering + \includegraphics[width=0.8\textwidth]{images/tkbs_ranking} + \caption{Rankings for only the test keyboards, gathered during the + post-experiment interview. It was possible to rank two or more keyboards the + same} + \label{fig:tkbs_ranking} +\end{figure} + +\textbf{[\xmark] Ratio of Positive and Negative Feedback} + +Lastly, we analysed all recordings of the post-experiment interviews and +categorized the feedback given for each keyboard into positive and negative +responses. We then calculated a ratio of these responses, which can be seen in +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 +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 +\textit{Nyx} and \textit{Athena} but would also indicate a worse experience with +those two keyboards \cite{baumeister_bad}. + +\begin{figure}[H] + \centering + \includegraphics[width=0.9\textwidth]{images/ratio_interview} + \caption{The ration of $\frac{Positive Responses}{Negative Responses}$ during + the semi-structured interview for all test keyboards} + \label{fig:ratio_interview} +\end{figure} + +\textbf{Conclusion} + +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 +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. + +\begin{phga_hyp*}[3 $\rightarrow$ \xmark] + Keys with lower actuation force are perceived as more satisfactory to type + with than keys with higher actuation force. +\end{phga_hyp*} + \subsection{Impact of Actuation Force on Muscle Activity} \label{sec:dis_emg} +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\% +of participants, could be interpreted as anecdotal evidence towards our +hypothesis, that actuation force has an impact on muscle activity. + +\begin{phga_hyp*}[4 $\rightarrow$ \xmark] + Differences in actuation force influence muscle activity while typing. +\end{phga_hyp*} + +%\subsection{Impact of an Adjusted Keyboard on Typing Speed, Error Rate and +% Satisfaction} + +\subsection{Implications for the Adjusted Keyboard} +\label{sec:dis_hera} + +As discussed in the previous sections, there were no statistically significant +differences in terms of satisfaction for any of the test keyboards, including +our adjusted keyboard \textit{Hera}. Still, the rather unconventional design +choice of non-uniform actuation forces across a keyboard did not negatively +influence the satisfaction compared to \textit{Aphrodite} which was often +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 +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 +reported a currently present disease of the left arm and wrist (Syndrome Sudeck, +complex regional pain syndrome (CRPS)), ranked Hera 30 points higher than all +other keyboards. \textit{I3Z4XI7H} also reported in the post-experiment +interview, that \textit{Hera} was surprisingly pleasant to use and that pain was +significantly lower than with all other keyboards including +\textit{Own}. However, because of the nearly identical scores to +\textit{Aphrodite} we have to reject our hypothesis, that an adjusted keyboard +is more satisfactory to use than standard keyboards. -\subsection{Impact of an Adjusted Keyboard on Typing Speed, Error Rate and - Satisfaction} -\label{sec:dis_hera} \ No newline at end of file +\begin{phga_hyp*}[7 $\rightarrow$ \xmark] + An adjusted keyboard is perceived as more satisfactory to type with compared to standard keyboards. +\end{phga_hyp*} diff --git a/images/ratio_interview.png b/images/ratio_interview.png new file mode 100644 index 0000000..01793a3 Binary files /dev/null and b/images/ratio_interview.png differ diff --git a/images/reg_ter_wpm.png b/images/reg_ter_wpm.png new file mode 100644 index 0000000..64d1982 Binary files /dev/null and b/images/reg_ter_wpm.png differ diff --git a/images/tkbs_ranking.png b/images/tkbs_ranking.png new file mode 100644 index 0000000..d2629ae Binary files /dev/null and b/images/tkbs_ranking.png differ diff --git a/ref_shelf.bib b/ref_shelf.bib index d0c2dd3..af4a1ad 100644 --- a/ref_shelf.bib +++ b/ref_shelf.bib @@ -922,4 +922,26 @@ number = {1}, volume = {13}, year = {2016}, pages = {67--75} +} + +@article{giese_sati, + title={Defining consumer satisfaction}, + author={Giese, Joan L and Cote, Joseph A}, + journal={Academy of marketing science review}, + volume={1}, + number={1}, + pages={1--22}, + year={2000}, + publisher={Vancouver} +} + +@article{baumeister_bad, + title={Bad is stronger than good}, + author={Baumeister, Roy F and Bratslavsky, Ellen and Finkenauer, Catrin and Vohs, Kathleen D}, + journal={Review of general psychology}, + volume={5}, + number={4}, + pages={323--370}, + year={2001}, + publisher={SAGE Publications Sage CA: Los Angeles, CA} } \ No newline at end of file diff --git a/thesis.tex b/thesis.tex index e3c05e5..a392c71 100644 --- a/thesis.tex +++ b/thesis.tex @@ -22,7 +22,10 @@ openright]{scrartcl} \usepackage[font=footnotesize]{caption} \usepackage[outputdir=auto]{minted} \usepackage[framemethod=tikz]{mdframed} -\usepackage{amssymb} + +\usepackage{pifont} +\newcommand{\cmark}{\ding{51}} +\newcommand{\xmark}{\ding{55}} \BeforeBeginEnvironment{minted}{\begin{mdframed}} \AfterEndEnvironment{minted}{\end{mdframed}} @@ -110,7 +113,96 @@ citecolor=red, \setlength{\textheight}{235mm} % Texthöhe % ------------------------------------------------------------------------------------ -\renewcommand{\thetheorem}{\relax} +% Fix for mdtheorem separator: https://tex.stackexchange.com/a/179794/226500 +\makeatletter +\DeclareDocumentCommand{\mdtheorem}{ O{} m o m o }% +{\ifcsdef{#2}% + {\mdf@PackageWarning{Environment #2 already exits\MessageBreak}}% + {% + \IfNoValueTF {#3}% + {%#3 not given -- number relationship + \IfNoValueTF {#5}% + {%#3+#5 not given + \@definecounter{#2}% + \expandafter\xdef\csname the#2\endcsname{\@thmcounter{#2}}% + \newenvironment{#2}[1][]{% + \refstepcounter{#2}% + \ifstrempty{##1}% + {\let\@temptitle\relax}% + {% + \def\@temptitle{\mdf@theoremseparator% + \mdf@theoremspace% + \mdf@theoremtitlefont% + ##1}% + \mdf@thm@caption{#2}{{#4}{\csname the#2\endcsname}{##1}}% + }% + \begin{mdframed}[#1,frametitle={\strut#4\ \csname the#2\endcsname% + \@temptitle}]}% + {\end{mdframed}}% + \newenvironment{#2*}[1][]{% + \ifstrempty{##1}{\let\@temptitle\relax}{\def\@temptitle{\mdf@theoremseparator\ ##1}}% <- the problem was here + \begin{mdframed}[#1,frametitle={\strut#4\@temptitle}]}% + {\end{mdframed}}% + }% + {%#5 given -- reset counter + \@definecounter{#2}\@newctr{#2}[#5]% + \expandafter\xdef\csname the#2\endcsname{\@thmcounter{#2}}% + \expandafter\xdef\csname the#2\endcsname{% + \expandafter\noexpand\csname the#5\endcsname \@thmcountersep% + \@thmcounter{#2}}% + \newenvironment{#2}[1][]{% + \refstepcounter{#2}% + \ifstrempty{##1}% + {\let\@temptitle\relax}% + {% + \def\@temptitle{\mdf@theoremseparator% + \mdf@theoremspace% + \mdf@theoremtitlefont% + ##1}% + \mdf@thm@caption{#2}{{#4}{\csname the#2\endcsname}{##1}}% + } + \begin{mdframed}[#1,frametitle={\strut#4\ \csname the#2\endcsname% + \@temptitle}]}% + {\end{mdframed}}% + \newenvironment{#2*}[1][]{% + \ifstrempty{##1}% + {\let\@temptitle\relax}% + {% + \def\@temptitle{\mdf@theoremseparator% + \mdf@theoremspace% + \mdf@theoremtitlefont% + ##1}% + \mdf@thm@caption{#2}{{#4}{\csname the#2\endcsname}{##1}}% + }% + \begin{mdframed}[#1,frametitle={\strut#4\@temptitle}]}% + {\end{mdframed}}% + }% + }% + {%#3 given -- number relationship + \global\@namedef{the#2}{\@nameuse{the#3}}% + \newenvironment{#2}[1][]{% + \refstepcounter{#3}% + \ifstrempty{##1}% + {\let\@temptitle\relax}% + {% + \def\@temptitle{\mdf@theoremseparator% + \mdf@theoremspace% + \mdf@theoremtitlefont% + ##1}% + \mdf@thm@caption{#2}{{#4}{\csname the#2\endcsname}{##1}}% + } + \begin{mdframed}[#1,frametitle={\strut#4\ \csname the#2\endcsname% + \@temptitle}]}% + {\end{mdframed}}% + \newenvironment{#2*}[1][]{% + \ifstrempty{##1}{\let\@temptitle\relax}{\def\@temptitle{:\ ##1}}% + \begin{mdframed}[#1,frametitle={\strut#4\@temptitle}]}% + {\end{mdframed}}% + }% + }% +} +\makeanother + \mdfdefinestyle{phga_sum}{ skipabove = 20pt, skipbelow = 20pt, @@ -123,6 +215,8 @@ citecolor=red, bottomline=false, } \mdtheorem[style=phga_sum]{phga_sum}{Relevance for this Thesis} + + \mdfdefinestyle{phga_hyp}{ skipabove = 20pt, skipbelow = 20pt, @@ -134,7 +228,9 @@ citecolor=red, leftline=false, rightline=false, bottomline=false, + theoremseparator={ }, } + \mdtheorem[style=phga_hyp]{phga_hyp}{Hypothesis} % ----Glossar-------------------------------------------------------------------------