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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Beyond Math Manipulatives: Smart Tangible Objects for Algebra Learning</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Anke V. Reinschluessel</string-name>
          <email>avr@uni-bremen.de</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Danny Thieme</string-name>
          <email>danny1@uni-bremen.de</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Tanja Döring</string-name>
          <email>tanja.doering@uni-bremen.de</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Rainer Malaka</string-name>
          <email>malaka@tzi.de</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Dmitry Alexandrovsky</string-name>
          <email>dimi@uni-bremen.de</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>University of Bremen</institution>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Bremen, Digital Media Lab</institution>
        </aff>
      </contrib-group>
      <fpage>9</fpage>
      <lpage>16</lpage>
      <abstract>
        <p>This workshop position paper presents ongoing research on using smart tangible objects for algebra learning. While mathematical manipulatives have played an important role in children's mathematics development for decades, employing tangible objects in the classroom has been rarely explored yet. In our work, we investigate the potentials of using smart objects for algebra learning. Our smart tiles are based on traditional algebra tiles, passive mathematical manipulatives used in many schools in Northern America, and we currently extend these by 1.) multimodal input and output capabilities, 2.) dynamic constraints and 3.) adaptivity and feedback. In this paper, we give an overview on the overall system concept, the interaction with the tangible objects and their current design, as well as on the potentials of actuated smart objects for future interaction.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Copyright © 2018 for this paper held by its author(s). Copying permitted for private
and academic purposes.</p>
    </sec>
    <sec id="sec-2">
      <title>Author Keywords</title>
      <p>Tangible user interface; smart objects; tabletop interaction;
embodied interaction; multimodal feedback; collaborative
learning; adaptive system.</p>
    </sec>
    <sec id="sec-3">
      <title>Introduction</title>
      <p>
        In math education, simple passive manipulatives provide
valuable “hands-on” approaches to teach students
abstract concepts, especially when the students start to learn
a novel unit of math, e.g., arithmetic, geometry, or
algebra. These approaches are in-line with models from
didactics like Bruner’s concrete-representational-abstract
approach [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] or the constructivistic objects-to-think-with
approach [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] that suggest to use physical objects for abstract
concepts, especially for beginners. While a considerable
body of research on using tangible user interfaces (TUIs)
for learning has been conducted, more research efforts
are needed to address the question how tangible user
interfaces can be made smarter in order to facilitate a better
learning environment and better support for learners.
In our research, we investigate the potentials of smart
objects for learning. The objects are based on traditional
algebra tiles, which are passive mathematical manipulatives
(see Fig. 1) as used in many schools in Northern America
to support algebra learning. We are extending these tiles to
smart “tiles” by 1.) multimodal input and output capabilities,
e.g., light and display, 2.) dynamic constraints, e.g.,
electromagnets attracting or repelling objects, and 3.) adaptivity
and feedback, e.g., user support and hints.
      </p>
      <p>
        In educational research tactile models are common, as
for example the ones by Bruner [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] or Kieran [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. They
showed that by using physical objects it is possible to teach
already small children mathematical, in particular
algebraic concepts. Common digital learning platforms, such
as Dragonbox1 lack the haptic and tactile components
and therefore the benefits that come with tangibility. By
transforming the algebra tiles to smart objects we want to
combine the richer feedback that can be provided by
digital platforms with the benefits of tactile interaction, where
the smart tiles themselves create dynamic constraints and
allow for multimodal input and output, also in combination
with a touch screen.
      </p>
    </sec>
    <sec id="sec-4">
      <title>Related Work</title>
      <p>
        Tangible user interfaces emerged in the 1990s, as Ishii and
Ullmer [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ] describe their vision for “tangible bits”. The gap
between the physical world and the digital world should be
closed by allowing users to directly manipulate these bits,
which can be everyday physical objects. Early examples
are the metaDesk [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ], the transBOARD [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] and the Urban
Planning Workbench [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ]. Since then, a popular
application domain for TUIs has been learning. Examples for using
tangibles for math learning have been provided by Falca¯ o
et al. [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], Girouard et al. [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], Manches and O’Malley [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ],
and Marichal et al. [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ], amongst many others. Others like
Rick [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] incorporate touch to be able to directly
manipulate math objects presented on a screen. Research about
how tangibles can support learning or how learning theories
can inform tangible development is for example presented
by the “Tangible Interaction Framework” by Hornecker and
Buur [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] or the “Tangible Learning Design Framework” by
Antle and Wise [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. They propose design principles for
tangibles and a taxonomy about the relationship between TUIs,
interactions and learning. Furthermore Marshall [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] and
Marshall, Price and Rogers [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] critically discuss how
tangibles can support learning.
      </p>
      <p>
        Examples for technological approaches for smart objects
are Sifteos (previously Siftables) [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ], small objects which
have all technology needed inside that react to each other
and encourage interaction with the objects themselves.
Sifteo cubes were launched as product in 2011 but are not
available anymore. A newer approach are the Actibles [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ],
which are tangibles with a smartwatch core and light
feedback. They allow a variety of interactions, including shaking,
tilting, stacking and neighbouring.
      </p>
    </sec>
    <sec id="sec-5">
      <title>Multimodal Algebra Learning with Tiles</title>
      <p>Algebra tiles as shown in Fig. 1 consist of three types of
tiles: single units used as “ones”, x-tiles and x2-tiles. Each
tile has a positive and a negative side, whereby the
negative side is colored red and the positive value is
represented by a unique color of that object. The tiles are
typically placed on a 2 2 area (compare Fig. 2), where the two
squares on the left represent the left side of an equation
and the two squares on the right represent the right side
of the equation. The top square on both sides is the
“addition zone”, i.e., all tiles there are connected by addition,
while the lower areas are the “subtraction zones”, i.e., all
tiles there are subtracted from the top ones. An equation,
for example 3 + ( x) 5 = x, is put up in tiles (see top
image in Fig. 3). There would be three positive ones and
one negative x-tile in the addition section on the left side,
and five positive ones in the subtraction zone. On the right
side there is just one positive x-tile in the addition zone.
The model comes with a set of possible actions that
correspond to typical algebraic manipulations, when dealing
with linear equations (addition, subtraction, multiplication
and division). Generally, the goal is to apply a sequence of
legal actions in order to transform the equation to another
form or to isolate the x-tile on one side and the one-tiles on
the other side. With the traditional tiles, a student can
transform the equation, but does not get any feedback about the
correctness of the actions. A teacher is still necessary to
verify them. On the contrary, in our approach, the algebra
tiles themselves are aware of the equation they are part of
and give feedback or hints about the steps. They can verify
the result of a student’s actions or support grouping of tiles
with visual feedback (see subsection Multimodal Input and
Output for more details). In combination with a touchscreen
and the capacity to track the tiles, multimodal algebra
learning is possible, as the benefits of the tangible tiles are
combined with the rich feedback such a system can provide.</p>
    </sec>
    <sec id="sec-6">
      <title>Interaction with Smart Tangible Objects</title>
      <p>In our current setup, the smart tangible objects are placed
on an interactive tabletop, where they are identified, located
and tracked with regard to orientation. This way, they are
integrated into a system that also uses the tabletop surface
for input and output capabilities (e.g., visual feedback and
multi-touch interaction). While we used passive tiles in early
versions of our systems (see Fig. 2, left side), the smart
tiles (see Fig. 4,5,6,7) are designed to provide rich
interaction capabilities themselves as this enhances the learning
environment and supports learners. Furthermore, this
approach would also allow for a setting in which the smart tiles
are used fully functional on their own without a multi-touch
table. The intelligence situated in our tangible objects and
their surrounding system currently improves the interaction
by three approaches: multimodal input and output
capabilities, dynamic constraints, and adaptivity and feedback.</p>
      <sec id="sec-6-1">
        <title>Multimodal Input and Output</title>
        <p>
          Multimodal input and output facilities of learning systems
can enhance learning experiences, as more senses are
involved in the learning process. Our tangibles follow this
approach by allowing direct haptic interaction with the tiles,
which can be moved around and placed in different areas
of the system for input, i.e., to perform algebraic
operations. Moreover, the objects directly give visual feedback,
for which we developed a model with two kinds of visual
feedback with central display and edge light feedback (see
also [
          <xref ref-type="bibr" rid="ref2 ref4">4, 2</xref>
          ] for a similar approach with low-resolution edge
displays). With this approach, the smart tiles can display
their current state in the center, e.g., the current value a
tile presents (see Fig. 6 and Fig. 7). At the same time they
communicate feedback on the performed operations via
edge light animations, e.g., if the moves were correct or
about current relations to surrounding tiles such as
grouping of tiles where tiles are combined to one unit. Other
output modalities such as sound and vibration feedback are
currently tested.
        </p>
      </sec>
      <sec id="sec-6-2">
        <title>Dynamic Constraints</title>
        <p>Our smart objects are designed to provide dynamic
constraints that guide the interaction. In our system, the
dynamic constraints can direct the grouping of tiles, which is
an essential action for performing operations and thus for
transforming and solving equations, they can also prevent
wrong combination of tiles (e.g., placing a tile of unit one
along the long side of an x-tile). The dynamic constraints
change according to the current value of each tile and the
possible combinations. We realized the dynamic constraints
by adding neodymium magnets and electromagnets to the
sides of the objects. When the electromagnets are switched
off, the neodymium magnets repel two objects. In case the
electromagnets are switched on, realized by closed circuits
when two fitting objects have contact, the objects attract
each other (see next section for further information). With
this approach, we can also stack objects. Furthermore, this
physical grouping also gives a great physical representation
of grouped units and enhances the haptic interaction.</p>
      </sec>
      <sec id="sec-6-3">
        <title>Adaptivity and Feedback</title>
        <p>Among the advantages of our system is that it can be adapted
and, to some degree, can automatically adapt to learners
with different levels and needs with regard to feedback and
hints provided. Partly, this is directly provided by the smart
tiles themselves via display and light feedback as well as
magnetic hints, partly this is currently communicated by
the surrounding system, in our case the interactive
tabletop system. In order to make the system smart and allow
for good feedback and hints, we have integrated and
further employ a number of approaches. One of these is
using Wolfram Alpha as computation knowledge engine2 that
computes algebraic transformations and allows for feedback
if an operation is a useful move towards the result for
example. Moreover, machine learning approaches can support</p>
        <sec id="sec-6-3-1">
          <title>2https://www.wolfram.com/engine/</title>
          <p>the identification of typical errors and the integration of
useful feedback, which will also improve the feedback the tiles
communicate directly. A central challenge lies in finding a
good balance of learner level and adequate feedback and
hints.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>Current Design of the Smart Tangible Objects</title>
      <p>For our tangible learning system with algebra tiles we started
with passive tiles and optical tracking. Using the
reacTIVision3 framework we had an early setup with tracking from
below to avoid occlusion problems. Currently we are
working on capacitive tracking in combination with motion
sensors to enable working on touch screens like the Microsoft
Surface Hub4. The underlying software on the touchscreen
is programmed in Unity5 and for supporting the equation
solving we are using the Wolfram Alpha API.
the tiles have contact and close a circuit through conductive
contacts. These contacts only close a circuit when the
pairing is allowed, which can be changed dynamically. If
combined, the two objects stick together and represent a unit.
Through the neodymium magnets stacking tiles is generally
also possible.</p>
      <p>A concrete example for the use case of the magnets
attracting would be two tiles of opposite value, e.g., +1 and
1, which can be paired as an “zero pair” and be removed
from the working area, as they cancel out. Additionally we
have light feedback to support the same pairing process
and grouping. With the light feedback one smart tile can
support more advanced learners, which already know that
+1 on the left side on an equation can be moved to right
side and then results in an 1. Smart tiles can
automatically change color to show this sign change.</p>
    </sec>
    <sec id="sec-8">
      <title>Envisioning Future Smart Tangible Objects</title>
      <p>
        The current setup and underlying model have some
limitations that could be addressed by actuated tangibles.
During solving, especially children tend to compare the
resulting x-tile in size with the one-tiles. For the future,
smart x-tiles that could change their shape regarding size
would be beneficial to this step, after the equation is solved.
Additionally it may occur the case that the user is able to
see the solution even though there is still more than one
x-tile on the area. Being able to change the size for all
xtiles synchronously would enhance the effect that all x are
the same. Thus, exploring shape change (c.f. the design
space of shape-changing interfaces by [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]) for tangible
presentations of variables in algebraic expressions would
be valuable. Another case is that especially after a
division it happens that multiple objects need to be removed at
once, which tends to be bothersome for the user. Here
actuated smart tiles would do the trick and after performing a
division, they could automatically remove themselves from
the working area. Vice versa, for multiplication they would
automatically enter the working area. Also in case of
providing help they could rearrange to give another view on the
equation. Approaches like used in small swarm robots as
the Zooid Swarm Robots [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ] could be applied to make the
tiles and the interactions smarter.
      </p>
    </sec>
    <sec id="sec-9">
      <title>Conclusion</title>
      <p>In this paper, we presented our approach for smart tangible
objects to support algebra learning. Starting from traditional
passive math manipulatives, we developed a concept to
make these learning objects more intelligent in order to
provide better learning environments that allow for rich and
multimodal interactions, dynamic constraints, as well as
adaptivity and feedback. We presented our current
prototype, including the overall math system and the design of
the smart objects. Furthermore, we discussed strategies to
design even smarter tangible objects, which would address
some of the current limitations by realizing actuation, both
with regard to shape-change as well as to self-moving tiles.
Overall, while our ongoing work focuses on providing a
contribution to designing smart tangible objects for learning
scenarios, our approaches to make the interaction and the
objects smarter could also be valuable for other application
contexts.</p>
      <sec id="sec-9-1">
        <title>Tangible Objects via Low-Resolution Edge Displays.</title>
        <p>ACM Press, 481–488. DOI:
http://dx.doi.org/10.1145/3024969.3025078
on Human factors in computing systems. ACM,
234–241.</p>
      </sec>
    </sec>
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