\begin{tikzpicture}[x=1mm, y=1mm]
\small
% Common/shared environment?
- \node[minimum width=20mm, draw=black!20, fill=black!20, text=black, text width=20mm, line width=10mm, circle, align=center,outer sep=0, execute at begin node=\setlength{\baselineskip}{10mm}](environment) at (0,0) {Shared environment};
+ \node[minimum width=15mm, draw=black!20, fill=black!20, text=black, text width=20mm, line width=4mm, circle, align=center,outer sep=0, execute at begin node=\setlength{\baselineskip}{10mm}](environment) at (0,0) {Shared environment};
% Middle line
%\draw [line width=30, draw=black!20, fill=black!50] (0,-15) -- (0,15);
\labelcell{execution}{Execution loop}{30,0}
%Perception
- \draw[->, -stealth', line width=1mm, draw=myred!50!black, shorten >= -4.0, shorten <= 0.0] (environment.west) to[out=90,in=45, looseness=1.1] node[pos=0.8, above, rotate=20] {Perception} (user.north east);
+ \draw[->, -stealth', line width=1mm, draw=myred!50!black, shorten >= -4.0, shorten <= 0.0] (environment.west) ++(2,0) coordinate(uloop) to[out=90,in=45, looseness=1.1] node[pos=0.8, above, rotate=20] {Perception} (user.north east);
%Action
- \draw [->, -stealth', line width=1mm, draw=myred!50!black, shorten <= -4.0] (user.south east) to[out=-45,in=270, looseness=1.1] node[pos=0.2, below, rotate=-20] {Action} (environment.west);
+ \draw [->, -stealth', line width=1mm, draw=myred!50!black, shorten <= -4.0] (user.south east) to[out=-45,in=270, looseness=1.1] node[pos=0.2, below, rotate=-20] {Action} (uloop);
%Input
- \draw[->, -stealth', line width=1mm, draw=myblue!50!black, shorten >= -4.0, shorten <= 0.0] (environment.east) to[out=-90,in=225, looseness=1.1] node[pos=0.8, below, rotate=20] {Input} (system.south west);
+ \draw[->, -stealth', line width=1mm, draw=myblue!50!black, shorten >= -4.0, shorten <= 0.0] (environment.east) ++(-2,0) coordinate(sloop) to[out=-90,in=225, looseness=1.1] node[pos=0.8, below, rotate=20] {Input} (system.south west);
%Output
- \draw [->, -stealth', line width=1mm, draw=myblue!50!black, shorten <= -4.0] (system.north west) to[out=135,in=90, looseness=1.1] node[pos=0.2, above, rotate=-20] {Output} (environment.east);
+ \draw [->, -stealth', line width=1mm, draw=myblue!50!black, shorten <= -4.0] (system.north west) to[out=135,in=90, looseness=1.1] node[pos=0.2, above, rotate=-20] {Output} (sloop);
\end{tikzpicture}
\tikzexternaldisable
- \caption{The similarity of a user and a system interacting with their environment, and through which they can interact together.}
+ \caption{The user and the system interact together through a shared environment.}
\label{fig:loops}
\end{figure}
We can reach objects \SI{50}{\cm} away from us, but not \SI{50}{m}.
There is also a \emph{precision} limitation, for example we can distinguish colors of wavelength \SI{100}{\nano\metre} apart, but not \SI{1}{\nano\metre} apart.
Precision is actually a range in difference, therefore according to Weber's law the threshold is proportional to the base stimulus value~\cite{fechner60}.
-Finally, there are \emph{processing} limitations, related to our cognitive abilities to interpret signals desulting from our perceptionns and actions.
+Finally, there are \emph{processing} limitations, related to our cognitive abilities to interpret signals resulting from our perceptions and actions.
Typically, illusions are distortions of what we could consider as ground truth.
Interactive systems have the same kind of limitations.
They are limited by the inputs and outputs they receive, and computing capactities to interpret them.
On one side, humans use machines to extend their limitations discussed above.
Extending human capacities with computers marked the beginning of Human-Computer Interaction, with the pioneer visions of Bush~\cite{bush45} and Engelbart~\cite{engelbart68}.
On the other side, all machines need humans otherwise they have no purpose.
-They all need instructions and data, and the all modify the environment or produce information.
+They all need instructions and data, and they all modify the environment or produce information.
These interactions between entities, whether they are humas or machines, require communication.
What I mean by communication is to produce a physical effect on a shared environment that the other entity can perceive.
+This shared environment has a common space and time, at a similar scale.
%It is important to note that what the second entity does not perceive this physical effect, but its own interpretation of it.
-In \refsec{sec:humanbehavior} we discussed how people perceive their environment, and in particular interactive systems.
-We presented how Norman's theory of action (see \reffig{fig:sevenstages}) explains the difference between the conceptual model of the system, and the perceptual model the users have of it based on their perception.
\paragraph{Seven stages of reaction}
+In \refsec{sec:humanbehavior} we discussed how people perceive their environment, and in particular interactive systems.
+We presented how Norman's theory of action (see \reffig{fig:sevenstages}) explains the difference between the conceptual model of the system, and the perceptual model the users have of it based on their perception.
I suggest that interactive systems follow a similar perceptual scheme, as depicted on \reffig{fig:mysevenstages}.
% The system senses a physical effect in its environment.
% Then interprets it to form input events, which are filtered and normalized interpretations of these effects.
Physical sensors measure physical effect in the environment.
Typically they measure the user movements, but it can be various other information such as light, temperature, moisture, or vibrations.
All such information is transformed into \emph{input events}.
-At this stage we notice that the infinite richness of the world is reduced to a small number of digits.
+At this stage we notice that the infinite richness of the world is reduced to a small number of bits.
%Let's discuss the simple example of a keypress on a keyboard.
%The only information in the digital world is whether a key is pressed or not.
For example when a user presses a key on a keyboard, the interactive system only senses whether the key is pressed or not.
-There is no information about the finger that pressed it, the speed of the finger or its trajectory.
-There is neither the possibility if a finger is hovering the key, if several fingers are pressing it, or even if it was pressed with the nose.
+There is usually no information about the finger that pressed it, the speed of the finger or its trajectory.
+%, even if it is possible \cite{marquardt11,goguey14,goguey17}.
+%We usually neither know if a finger is hovering the key, if several fingers are pressing it, or even if it was pressed with the nose.
+%And this is also possible to sense it and improve interaction~\cite{rekimoto03,harrison11}.
Input events have to be treated as tokens, or lexical units.
They are interpreted as \emph{input phrases} with grammars or finite automatons~\cite{appert06} and form the building blocks of \defwords{interaction techniques}{interaction technique}~\cite{nigay93}.
The \emph{software} part is an interaction machine that receives streams of input phrases, interprets them with algorithms, and eventually sends back information through output streams.
A good design of the input chain senses the right phenomenons, at an appropriate amplitude, with a sufficient spatial and temporal resolution, and with little distortions.
These information must be combined correctly to form a meaningful sequence of actions that the users must perform.
For example, the \defword{Midas touch} problem is a usual issue with 3D gestural interaction.
-Since the sensors continuously observe the users movements, there is no obvious segmentation.
+Since the sensors observe the users movements without activation or interruption, there is no obvious segmentation.
The system has no way to know if the users move their hand to interact with the system, or for scratching their nose for example.
\defword{Occlusion} has the opposite issue.
%, occlusion is the other problem with vision-based gesture sensors.
The sensor cannot get position information for objects outside of its field of view.
-In these situations, we can grow the funnel of evaluation respectively by adding segmentation gestures, and using multiple cameras.
+In these situations, we can grow the funnel of evaluation respectively by adding segmentation gestures (see \refsec{sec:summon} below), and using multiple cameras.
\paragraph{Funnel of execution}
Last, the physical effect can be inconsistent for the same command.
Some haptic devices can behave differently depending on ambient conditions (\eg temperature, finger moisture, cleanliness).
+\paragraph{Computing affordance}
+
+
+
\begin{idee}
Communication: humans and system both have a perceptual model of the other.
It does not necessarily match their conceptual model.
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