Fractal Theory
BY : EHSAN HAMZEI - 810392121
Fractal? 1
 A fractal is generally "a rough or fragmented geometric
shape that can be subdivided in parts, each of which is (at
least approximately) a reduced-size copy of the whole“ – (B.
Mandlebrot).
 This property is called self-similarity.
Graph Theory History 2
 Lewis Fry Richardson, “War & and Common
Border”
 Benoit Mandelbrot, “How Long Is the Coast of
Britain”
Properties 3
 A fractal often has the following features:
 It has a fine structure at arbitrarily small scales.
 It is self-similar (at least approximately).
 It is too irregular to be easily described in traditional
Euclidean geometric.
 It has a dimension which is non-integer.
 It has a simple and recursive definition.
Examples of Fractals: 4
 Natural:
 Mathematical:
Example (Creating) 5
 Example: Cantor set.
 The Cantor set is obtained by deleting recursively the 1/3 middle
part of a set of line segments.
Example (Creating) 6
 Properties of the Cantor set C:
 C has a structure at arbitrarily small scale.
 C is self-similar
 The dimension of C is not an integer!
 Length = limn->∞((2/3)n)=0. (But infinite points…)
Example 2 (Creating) 7
 The Koch curve is obtained as
follows:
 start with a line segment S0.
 delete the middle 1/3 part of S0
and replace it with two other 2-
sides.
 Subsequent stages are generated
recursively by the same rule
 But >> limit K=S∞ !!
Fractal Dimension 8
 A mathematical description of dimension is based on how the
"size" of an object behaves as the linear dimension increases.
 In 1D, we need r segments of scale r to equal the original segment.
 In 2D, we need r2 squares of scale r to equal the original square.
 In 3D, we need r3 cubes of scale r to equal the original cube.
Fractal Dimension 9
 This relationship between the dimension d, the scaling
factor r and the number m of rescaled copies required
to cover the original object is thus:
 Rearranging the above equation:
Back to Examples
 M = 2
 R = 3
 D = ln(M)/ln(R) = ln2/ln3 = 0.63
10
Back to Examples 11
 M = 4
 R = 3
 D = ln4/ln3 = 1.26
References 11
 Didier Gonze, “Fractals: theory and applications”
Lecture Note Libre de Bruxelles University
 Mandelbort, “Fractal Theory”.
Thanks 12

Fractal Theory

  • 1.
    Fractal Theory BY :EHSAN HAMZEI - 810392121
  • 2.
    Fractal? 1  Afractal is generally "a rough or fragmented geometric shape that can be subdivided in parts, each of which is (at least approximately) a reduced-size copy of the whole“ – (B. Mandlebrot).  This property is called self-similarity.
  • 3.
    Graph Theory History2  Lewis Fry Richardson, “War & and Common Border”  Benoit Mandelbrot, “How Long Is the Coast of Britain”
  • 4.
    Properties 3  Afractal often has the following features:  It has a fine structure at arbitrarily small scales.  It is self-similar (at least approximately).  It is too irregular to be easily described in traditional Euclidean geometric.  It has a dimension which is non-integer.  It has a simple and recursive definition.
  • 5.
    Examples of Fractals:4  Natural:  Mathematical:
  • 6.
    Example (Creating) 5 Example: Cantor set.  The Cantor set is obtained by deleting recursively the 1/3 middle part of a set of line segments.
  • 7.
    Example (Creating) 6 Properties of the Cantor set C:  C has a structure at arbitrarily small scale.  C is self-similar  The dimension of C is not an integer!  Length = limn->∞((2/3)n)=0. (But infinite points…)
  • 8.
    Example 2 (Creating)7  The Koch curve is obtained as follows:  start with a line segment S0.  delete the middle 1/3 part of S0 and replace it with two other 2- sides.  Subsequent stages are generated recursively by the same rule  But >> limit K=S∞ !!
  • 9.
    Fractal Dimension 8 A mathematical description of dimension is based on how the "size" of an object behaves as the linear dimension increases.  In 1D, we need r segments of scale r to equal the original segment.  In 2D, we need r2 squares of scale r to equal the original square.  In 3D, we need r3 cubes of scale r to equal the original cube.
  • 10.
    Fractal Dimension 9 This relationship between the dimension d, the scaling factor r and the number m of rescaled copies required to cover the original object is thus:  Rearranging the above equation:
  • 11.
    Back to Examples M = 2  R = 3  D = ln(M)/ln(R) = ln2/ln3 = 0.63 10
  • 12.
    Back to Examples11  M = 4  R = 3  D = ln4/ln3 = 1.26
  • 13.
    References 11  DidierGonze, “Fractals: theory and applications” Lecture Note Libre de Bruxelles University  Mandelbort, “Fractal Theory”.
  • 14.