Appendix D: Basic Procedures
Under the supervision of the control system, different blocks are
activated, thereby processing information in alternative ways in
order (a) to decide whether all places in a given region have been
examined and (b) to create new regions.
![](Images%20Appendix%20D/image012.gif) |
Figure D2. Examined places. The activation of g1
depends on the active places and the values of the
associations between places and the exploratory goal.
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Figure D3.
Examined places. The agent represented with a gray oval
examines places 2, 3, 4, 6, 7, 8, 10, 11, and 12. Places
2, 6, and 10 are occupied by obstacles. Places 1, 5, and
9 remain unexamined. Black lines radiating from the
agent represent sensors, black circles represent
examined places, and white circles represent unexamined
places. Places 2, 6 and 10 contain an obstacle.
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Examined places. While
moving through a region, the representation of the current place
(see
in
Figure D1) activates the
representation of the region where that place is located through
place-region associations (see
in
Figure D1). In turn, region-place
associations activate the representations of all places in that
region (see
in
Figure D1) and, as explained below,
through place-exploratory goal associations the agent is able to
determine whether or not all places have been examined (see
in
Figure D1).
Figure D2 shows the unit that stores the
connections, Wi,g1, between places and the goal
being examined (see Figure 3). When
all the places that belong to the current region are activated, if
all Wi,g1 are zero, then g1 =
Ai
pi Wi,g1
= 0. This means that the whole region has been examined.
If, on the other hand, there is at least one place for which Wi,g1>
0, then there still are unexamined places.
Figure D3
shows that places adjacent to examined places and occupied by
obstacles are counted as examined (places 2, 6, and 10). Places that
are not adjacent to examined places due to the presence of obstacles
and therefore out of the reach for the agent's sensors, are counted
as unexamined places (places 1, 5, 9).
Creation of a new region. If
not all places have been examined (g1
> 0), then some unexplored places in the region are unreachable when
the agent is at any place of the already explored places. Therefore,
a new subregion should be defined.
There are three
possible cases concerning the status of an explored region.
Case 1: All places can be examined,
there are no obstacles. Figure D4 shows 6 accessible places
in a region that has not been explored. Because the agent can enter
all the places in the regions the weights connecting all place
representations remain equal to 1. When the agent applies the
examined places procedure
mentioned above, g1
equals 0.
![](Images%20Appendix%20D/image016.gif) |
Figure D4.
Accessibility: Continuous region. All places are
examined and the region remains the same.
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Case 2: All
places can be examined, some contain obstacles. Figure D5 shows 5
accessible places in an unexplored region. Because place 2 cannot be
entered, the connections between the representations of all places
and place 2 are set to 0. All other connections remain equal to 1.
As before, when the agent applies the examined places procedure, g1
equals 0. Even if place 2 is occupied by an obstacle, it is
considered as examined.
![](Images%20Appendix%20D/image018.gif)
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Figure D5.
Accessibility: Continuous region with one obstacle. All
places are examined. The region remains the same.
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Case
3: Not all places can be examined. Figure D6 shows 4
accessible places in a region that has not been explored. When the
agent is in place 1 or place 4, because places 2 and 5 are not
accessible their connectivity with places 1 and 4 are made equal to
0, whereas the connection between place 1 and place 4 stays equal to
1. As mentioned, places 2 and 5 are occupied by obstacles and are
considered as examined. Because they are out of reach for the
sensors of the agent, place 3 and 6 are considered unexamined.
Therefore, when the agent applies the
examined places procedure,
g1 is greater
than 0. This result indicates that there are unexamined places that
are disconnected from places 1 and 4, and therefore, two new
subregions should be defined.
![](Images%20Appendix%20D/image020.gif)
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Figure 6.
Accessibility: Continuous region. All places are
examined and the region remains the same.
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In order to update the
place-region and region-place connections, the system activates the
representation of the examined places (see Figure D7) and the
representation of region E, and as a consequence, places E1, E2, E4
and E5 remain part of that region. At the same time because the
representations of the unexamined places are not active when the
representation of region E is active, unexamined places E3 and
E6 are disconnected from region E. When the previous step is
completed, because region E has not been completely explored, a new
region E' is connected to the unexamined places E3 and E6.