Matakuliah
Tahun
Versi
: T0264/Intelijensia Semu
: Juli 2006
: 2/1
Pertemuan 20
Understanding Continued
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Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• << TIK-99 >>
• << TIK-99>>
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Outline Materi
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Materi 1
Materi 2
Materi 3
Materi 4
Materi 5
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14.3. Understanding as Constraint Satisfaction
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There are two important steps in the use of
constraints in problem solving
1. Analyze the problem domain to determine
what the constraint are.
2. Solve the problem by applying a constraint
satisfaction algorithm that effectively uses the
constraints from step 1 to control the search.
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Understanding as Constraint Satisfaction
contd’
A Line Drawing
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•
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An Obscuring Edge  A boundary between objects, or
between objects and the background
A Concave Edge  An edge between two faces that
form an acute angle when viewed from outside the
object
A Convex Edge  An edge between two faces that
form an obtuse angle when viewed from outside the
object
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Trihedral Figures
• Some Trihedral Figures
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Nontrihedral Figures
• Some Nontrihedral Figures
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Line-Labeling
• Line-Labeling Conventions:
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Line-Labeling contd’
• An Example of line Labeling :
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The Four Trihedral Vertex Type
FORK : Sudut < 90o, dan ARROW : sudut > 90o
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A Figure Occupying One Octant
• Consider the drawing, which accupies one of the eight octant formed
by the intersection of the planes corresponding to the faces of vertex A.
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The Vertices of a Figure Occupying One Octant
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The Eighteen Physically Possible
Trihedral Vertices
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A Simple Example of the Labeling Process
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Algorithm : Waltz
1.
Find the lines at the border of the scene boundary and
label them. These lines can be found by finding an
outline such that no vertices are outside it. We do this
first because this labeling will impose additional
constraints on the other labelings in the figure.
2.
Number the vertices of the figure to be analyzed. These
number will correspond to the order in which the vertices
will be visited during the labeling process. To decide on
a numbering, do the following :
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Algorithm : Waltz
a.
Start at any vertex on the boundary of the figure. Since
boundary lines are known, the vertices involving them
are more highly constrained than are interior ones.
b.
Move from the vertex along the boundary to an
adjacent unnumbered vertex and continue until all
boundary vertices have been numbered.
Number interior vertices by moving from a numbered
vertex to some adjacent unnumbered one. By always
labeling a vertex next to one that has already been
labeled, maximum use can be made of the constraints.
c.
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Algorithm : Waltz
3. Visit each vertex V in order and attempt to label it by doing
the following :
a. Using the set of possible vertex labelings given in
figure (the eighteen physically possible trihedral
vertices), attach to V a list of its possible labelings.
b. See whether some of these labelings can be
eliminated on the basis of local constraints. To do this,
examine each vertex A that is adjacent to V and that
has already been visited. Check to see that for each
proposed labeling for V, there is a way to label the
line between V and A in such a way that at least one of
the labelings listed for A is still possible. Eliminate from
V’s list any labeling for which this is not the case.
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Algorithm : Waltz
c.
Use the set of labelings just attached to V to constraint
the labelings at vertices adjacent to V. For each vertex
A that was visited in the last step, do the following :
i) Eliminate all labelings of A that are not consistent
with at least one labeling of V.
ii). If any labelings were eliminated, continue constraint
propagation by examining the vertices adjacent to A
and checking for consistency with the restricted set of
labeling now attached to A.
iii). Continue to propagate until there are no adjacent
labeled vertices or until there is no change made to the
existing set of labelings.
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<< Closing >>
End of Pertemuan 20
Good Luck
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