\paragraph{Discussion}
-I will not cover the experimental details, and the full analysis.
-Interested readers will find more details in the corresponding paper~\cite{potier16}.
-I will rather summarize the main findings and discuss further some aspects.
-
+Interested readers will find more details on the experimental details and the full analysis in the corresponding paper~\cite{potier16}.
+Here I will focus on the main findings.
We designed the patterns with several shapes and densities.
Therefore we expect partitipants to group patterns of same shapes or densities.
However the MDS analysis fails at identifying a good sets of clusters with 2 or 3 dimensions.
This means that this is unlikely there is a consensual grouping strategy among users and conditions.
-Looking at the data, we observed participants often grouped vertical and horizontal lines per shape in both conditions.
+We observed participants often grouped vertical and horizontal lines per shape in both conditions.
We hypothesize this is due to the fact that the sensation with these two shapes is different whether you explore them horizontally or vertically.
+%The limitation of an MDS analysis in general is that it measures a user-defined notion of similarity.
+%When participants group two items together, it does not necessarily mean they could not distinguish them.
+%It means they consider they fit together for whatever reason.
+
%Participants also grouped together high-density dots, circles and squares.
%They most likely identified them as a fine-grain
Next, we analyzed the composition of pattern groups made by participants.
We observed if groups contained the same \textsc{shape}, same \textsc{density} or if users \textsc{mixed} shapes and densities.
In the paper condition, participants used more often a \textsc{shape} or \textsc{density} strategy than a \textsc{mixed} strategy.
-In particular when they made groups of 6 or 7 items, they dominantly used a \textsc{shape strategy}.
+In particular when they made groups of 6 or 7 items, they dominantly used a \textsc{shape} strategy.
Interestingly, in the Stimtac condition participants mostly used a \textsc{mixed} strategy, and made more groups of 2 items.
Because the grouping strategy was different in the two conditions, we assume that they perceived the patterns differently with the paper cards and Stimtac.
%Overall, participants were able to identify shapes and den- sities, both with the paper and the programmable friction device. They mostly interpret patterns with both methods in a same way. They used different strategies only when patterns had fine details, which suggests that differences occur at the limit of the input and output resolution of pro- grammable friction devices. The whole device produces the same sensation across the device regardless the finger location. This means that the output refresh rate, input rate and input resolution contribute to the signal actually produced. Our results suggest that these limits have an impact on the interpretation of the patterns represented.
-Limitation of MDS: not similar does not mean we cannot distinguish
-
\subsubsection{Conclusion}
-On a methodological point of view we see that except at the limits of the device capabilities, the interpretation of simple patterns with a programmable friction device or with a physical surface is similar. This means for example that paper cards can be used for prototyping such interactions for a best case scenario.
+This project is a typically interdisciplinary project in which research was made on two fronts at the same time.
+On one side our Electrical engineering colleagues designed, simulated and implemented the device itself.
+On our side we evaluated the perception the haptic effect by users.
+Both research benefitted to the other.
+Our main contribution was the evaluation of variable friction parameters for the design of
+an output vocabulary with programmable friction devices.
+
+We first worked on the lexical level, and evaluated the JND of steps for six reference values of friction.
+We observed differences of perception between reference values.
+We attributed these differences to both the non-linearity of the mechanical effect resulting from the command, and the perception of the mechanical effect.
+As a result, the commands were adapted on the device.
+
+Then we worked on the syntactic level, and proposed definitions of tactile patterns and textures.
+We compared the users' estimation of similarity of tactile patterns made of different shapes and densities implemented with a Stimtac device and with coated paper cards.
+We observed differences of grouping stragety acrross conditions, suggesting differences of perception between the haptic device and the paper cards.
+It means that results about perception made with research prototypes are hard to generalize, and that using physical props is an alternative to evaluate best-case scenarios.
+
-On a perception point of view, we remind that this result stands with a one finger exploration.
-This means we do not exploit the richness of large surfaces and the ability to feel different sensations at the same time on different fingers.
-We are not aware of any technology able to produce such effects.
-Many studies, especially with visually impaired users take advantage of this capability, with embossed paper for example.
-We also remind that programmable friction devices like the STIMTAC we used cannot produce edge sensations, because it requires to feel two different sensations under the finger.
-This limitation did not have a particular effect on our results. It could be an issue for a realistic simulation of physical textures. In our case we do not require a realistic sensation.
+%\cite{bertin83}
+%Engineering: replicability, paper…
+
+%On a methodological point of view we see that except at the limits of the device capabilities, the interpretation of simple patterns with a programmable friction device or with a physical surface is similar. This means for example that paper cards can be used for prototyping such interactions for a best case scenario.
+
+%On a perception point of view, we remind that this result stands with a one finger exploration.
+%This means we do not exploit the richness of large surfaces and the ability to feel different sensations at the same time on different fingers.
+%We are not aware of any technology able to produce such effects.
+%Many studies, especially with visually impaired users take advantage of this capability, with embossed paper for example.
+%We also remind that programmable friction devices like the STIMTAC we used cannot produce edge sensations, because it requires to feel two different sensations under the finger.
+%This limitation did not have a particular effect on our results. It could be an issue for a realistic simulation of physical textures. In our case we do not require a realistic sensation.
\subsection{Vibrotactile widgets}
In this work we explore actuation and motion as a way of interacting with computer peripherals in the way they were not designed for.
%We discuss scenarios in which computer peripherals are tangible objects for interaction with digital information.
-\subsection{Related work}
+\subsubsection{Related work}
We describe below evolutions of the desktop interface, the use of motion as an output modality, and shape changing interfaces.
This object was specifically designed to behave this way.
At the opposite, Kim et al. designed an inflatable mouse~\cite{kim08} which can either give notifications, or be used as an elastic input device for continuous rate control.
-\subsection{Actuated peripherals}
+\subsubsection{Actuated peripherals}
In this project we use both the concepts of motion as output, and shape changing interfaces to redesign computer peripherals.
We discuss design rationales on the device level, desktop level, and envision extending the concept to en entire room or a house.
-\subsubsection{Device level}
+\paragraph{Device level}
+***
Motion is an essential aspect of interaction with peripherals.
Pointing devices rely on movement measurements.
The possibilities of such a keyboard go beyond text typing and keyboard shortcuts. Similarly to Relief~\cite{leithinger10}, it is a shape changing device which can be used to display information.
-\subsubsection{Desktop level}
-
+\paragraph{Desktop level}
+***
%Several augmented devices exist in the literature.
%They are essentially isolated devices, not a set of coherent devices which share the same behavior.
We observed people when they use a desktop computer, and identified situations in which they move their peripherals besides interaction with the computer.
The user has no control over the devices in this situation.
-\subsubsection{Going further}
-
+\paragraph{Going further}
+***
Looking at the office environment, there are many other objects involved.
They can be actuated to provide other interactive scenarios.
Probst et al. presented a prototype of chair they use for input\cite{probst14}.
The obvious application is to maintain sunlight at a specific location in the house.
But there may be many interesting interactive scenarios to study with such a building.
-\subsection{Conclusion}
+\subsubsection{Conclusion}
The early studies about TUIs used to consider everyday objects for interaction.
Nowadays, computer peripherals became everyday objects.
projects / hdr.git / commitdiff