-Artificial Neural NetworkChapter 2 Basic Model 朝陽科技大學 資訊管理系 李麗華 教授 Introduction to ANN Basic Model 1.

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Transcript -Artificial Neural NetworkChapter 2 Basic Model 朝陽科技大學 資訊管理系 李麗華 教授 Introduction to ANN Basic Model 1.

Slide 1

-Artificial Neural NetworkChapter 2 Basic Model
朝陽科技大學
資訊管理系
李麗華 教授


Slide 2

Introduction to ANN Basic Model
1. Input layer
2. Hidden layer
3. Output layer

4. Weights
5. Processing Element(PE)
6. Learning

7. Recalling
8. Energy function
朝陽科技大學 李麗華 教授

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Slide 3

ANN Components (1/4)
1. Input layer:[X1,X2,…..Xn]t , where t means vector transpose.
2. Hidden layer: I j => net j => Y j
3. Output layer:Yj
• Three ways of generating output: normalized,
competitive output, competitive learning
4. Weights :Wij means the connection value between layers
Wij

X1

Y1

X2












Yj

Xn
朝陽科技大學 李麗華 教授

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Slide 4

ANN Components (2/4)
5. Processing Element(PE)
Ij 

(A)Summation Function:

W

Xi

ij

(supervised)

i

or I 
j

 (X

i

 W ij )

(unsupervised)

2

i

(B)Activity Function: net

j

n
 I j or net

or net

n
j

 I j  C  net
n

n 1

 Ij CIj
n

j

n 1
j

(C)Transfer Function:
1.
2.
3.

Discrete type
Linear type
Non-linear type

朝陽科技大學 李麗華 教授

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Slide 5

ANN Components (3/4)
6. Learning:
– Based on the ANN model used, learning is to
adjust weights to accommodate a set of training
pattern in the network.

7. Recalling:
– Based on the ANN model used, recalling is to
apply the real data pattern to the trained network
so that the outputs are generated and examined.

朝陽科技大學 李麗華 教授

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Slide 6

ANN Components (4/4)
8. Energy function:
– Energy function is a verification function which
determines if the network energy has converged to its
minimum. Whenever the energy function approaches
to zero, the network approaches to its optimum
solution.

朝陽科技大學 李麗華 教授

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Slide 7

Transfer Functions (1/3)
• Discrete type transfer function:
1
Yj=

net j > 0
if

0

net j

1
Ynj=

1

Step function or
perceptron fc.

0

<=0

-1
1

net j > 0

Yn-1j if
0

netj=0

Hopfield-Tank fc.

0

net j<0

-1

1
1
if

Yj =
-1

net j > 0

Signum fc.

net j<=0

朝陽科技大學 李麗華 教授

0

-1

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Slide 8

Transfer Functions (2/3)
• Discrete type transfer function:
1
Yj =

0

if

netj = 0

-1

Yn-1j
-1

Signum0 fc.

0

net j<0

1
Ynj =

1

net j > 0

-1
1

net j > 0
if

net j = 0

BAM fc.

net j<0

朝陽科技大學 李麗華 教授

0

-1

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Slide 9

Transfer Functions (3/3)
• Linear type:
Yj = net j

net j

net j > 0

Yj =

if
0

net j <=0

• Nonlinear type transfer function:
1

Yj =

Yj =

1 



net

j



net

j

 net

Sigmoid function

j



 net

j



 net

j

Hyperbolic Tangent function

朝陽科技大學 李麗華 教授

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Slide 10

Energy function
(a) The energy function for supervised network learning:
E=

1
2

 T

j

Y

j



2

where E is the energy value

j

E

ΔW=   ‧

this is the value for adjusting weight Wij

 W ij

(b) The energy function for unsupervised network learning:
E=

ΔW=

1
2

 X

i

 W ij 

2

i

 ‧

E
 W ij

this is the value for adjusting weight Wij

朝陽科技大學 李麗華 教授

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