End - PowerPoint PPT Presentation

1 / 33
About This Presentation
Title:

End

Description:

Human brain can generalize from abstract. Recognize patterns in the ... transfer function: hyperbolic tangent sigmoid or logistic sigmoid,... ???? ??????? ... – PowerPoint PPT presentation

Number of Views:48
Avg rating:3.0/5.0
Slides: 34
Provided by: sar102
Category:
Tags: end | sigmoid

less

Transcript and Presenter's Notes

Title: End


1
???? ??? ????
  • ????? ???????
  • ??????? ?????
  • ???? ?????

2
????? ?????
????? ???? ????
????? ? ?????
???? ???? ??????
??????? ?? ??????
????? ???? ??? ????
???? ????? ???
???? ? ??????
??? ???? ?????
End
3
????? ???? ??? ????
  • What is a Neural Network?
  • Collection of neurons
  • Computes some function
  • Takes input
  • Produces output
  • Can learn

4
????? ???? ??? ????
  • Human Brain Function
  • Human brain can generalize from abstract
  • Recognize patterns in the presence of noise
  • Recall memories
  • Make decisions for current problems based on
    prior experience
  • Neural Network Neurons
  • Receives n-inputs
  • Multiplies each input by its weight
  • Applies activation function to the sum of results
  • Outputs result

5
???? ???? ??????
  • What is an Artificial Neural Network (ANN)?
  • The computational ability of a digital computer
    combined with the desirable functions of the
    human brain.

6
???? ???? ??????
  • Biological Neurons
  • Artificial Neurons

7
???? ???? ??????
  • ?????? ???? ???? ??????

8
???? ???? ??????
  • ????? ??? ???? ???? ? ???? ??????

9
???? ? ??????
  • How does a neural network learn?
  • A neural network learns by determining the
    relation between the inputs and outputs.
  • By calculating the relative importance of the
    inputs and outputs the system can determine such
    relationships.
  • Through trial and error the system compares its
    results with the expert provided results in the
    data until it has reached an accuracy level
    defined by the user.
  • With each trial the weight assigned to the inputs
    is changed until the desired results are reached.

10
???? ? ??????
  • How the Process Works ?
  • Step 1 Initialisation
  • Set initial weights to random numbers in your
    range
  • Step 2 Activation
  • Activate the perceptron by applying inputs and
    desired output.( training set data) Calculate
    the actual output at iteration .

11
???? ? ??????
  • Step 3 Weight training
  • Update the weights of the perceptron.The weight
    correction is computed by the delta rule
  • Step 4 Iteration
  • Increase iteration p by one, go back to Step 2
    and repeat the process until convergence.

12
????? ???? ??? ????
  • Different Learning Algorithms
  • Backpropagation
  • Delta Learning Rule
  • Forward Propagation
  • Hebb Learning Rule
  • Simulated Annealing
  • Genetic Algorithms
  • Types of Networks
  • Multi-Layer-Perceptron
  • Hopfield Net
  • Kohonen Feature Map
  • Adaptive Resonance Theory (Art), Fussy ArtMap
  • Type of Learning
  • Supervised
  • Unsupervised

13
????? ???? ??? ????
Muli-Layer Perceptron
Hopfield Net
14
????? ? ????? ??????? ?? ???? ??
  • Neural Networks can be extremely complex and hard
    to use
  • The programs are filled with settings you must
    input and a small amount of data will cause your
    predictions to have error
  • The results can be very hard to interpret as well
  • Dead-end situations are hard to avoid
  • Neural networks can find relations that no one
    ever guess they exist
  • Since they are data dependent performance will
    improve as sample size increases
  • Regression performs better when theory or
    experience indicates an underlying relationship

15
??????? ?? ??????
  • Marketing
  • Trading and financial forecast
  • Future price estimation
  • Exchange rate forcast
  • Bankruptcy prediction
  • Stock performance and selection
  • Portfolio assignment and optimization

16
???? ???????
  • Large amount of data available in databases
  • Customers data available in firms own database
    or can be supplied by companies which sell these
    information
  • These information can be applied for marketing
    purposes e.g. direct marketing

17
???? ???????
  • Direct marketing drives high cost
  • Targeting customers who are more likely to spend
    money !
  • Direct mailing to customers

18
???? ???????
  • In this example one charity organization apply
    direct mailing promotion to raise their funds
  • Neural network applied to target selection in
    this case
  • Neural network should determine those customers
    in data base who would be interested in the offer
    being maid
  • Neural network in a learning system which can
    adapt the nonlinearity in the data to capture
    complex

19
???? ???????
  • There can be different types of databaises with
    variety of data
  • There should be most important aspects of a
    successful mailing compa
  • Analytical methods (data mining, sensitivity
    analysis, )
  • Experiment ( some researches , literature , )
  • Causal relations
  • experties

20
???? ???????
  • Data mining offers following representations as
    purchase history
  • Recency of purchase
  • Frequency of purchase
  • Monetary value
  • These variables are called RFM variables

21
???? ???????
  • In working with models like ANN enough care must
    be taken about the process the data
  • data preparation publish inpublish out
  • Determining causal relations
  • Knowledge about customers attitude history

22
???? ???????
  • Mailing strategy
  • Who should be mailed and how frequent
  • How frequently Should be organized
  • How their promotional material should be
    organized

23
???? ???????
  • Classification or prediction
  • Asymmetrical misclassification costs
  • Weigh misclassified responders
  • Or target scoring to show customers willingness

24
???? ???????
  • What is ANN job
  • Trained to determine correct set of network
    parameters
  • Good indication of the willingness according to
    network inputs
  • Indeed, indication of responsive behavior
    regarding their characteristics
  • A nonlinear regression model

25
???? ???????
  • Network configuration
  • feed-forward neural networks for practical
    purpases
  • number of hidden layers
  • methods growing and pruning, heuristic search,
    optimization by evllutionary computation (e.g.
    GA). experiment,...

26
???? ???????
  • selecting network parameters
  • experiments show that one hidden layer provides
    model with sufficient accuracy in target
    selecting
  • transfer function hyperbolic tangent sigmoid or
    logistic sigmoid,...

27
???? ???????
  • data preparetoin
  • discription of raw data
  • size of data set
  • feature selection
  • process selected features
  • selecting suitabale training and validation sets

28
???? ???????
  • description of raw data
  • a well-known Dutch charuty organization
  • more than 725000 supporters in the internal
    database
  • database including
  • mailing dates,
  • amount of donation,
  • date of donation in response to a particular
    mailing,...

29
???? ???????
  • size of data set
  • aoge amount of records makes network too complex
    and slow
  • data size should be large enough and not too big
  • 1000 random records representativies of the whole
    data

30
???? ???????
  • Feature selection
  • neccessarily not all features are useful and
    meaningful for target selection
  • features that sumarize the most important aspects
  • RFM variables
  • table 2 the features used for the charity case
    study

31
??? ???? ?????
  • Neural networks provide ability to provide more
    human-like AI
  • Takes rough approximation and hard-coded
    reactions out of AI design (i.e. Rules and FSMs)
  • Still require a lot of fine-tuning during
    development

32
?????
  • Artificial Neural Network in Finance and
    Manufacturing,Joarder Kamruzzaman
  • Neural Networks And Their Statistical
    Application, Clint Hagen
  • Statistics Senior Seminar 2006
  • Neural Networks , Megan Vasta
  • Artificial Intelligence Neural Networks, Amir
    Hesami
  • Interview with Jeff Hannan, creator of AI for
    Colin McRae Rally 2.0
  • Interview with Derek Smart, creator of AI for
    Battlecruiser 3000AD
  • Neural Netware, a tutorial on neural networks
  • Sweetser, Penny. Strategic Decision-Making with
    Neural Networks and Influence Maps, AI Game
    Programming Wisdom 2, Section 7.7 (439 46)
  • Russell, Stuart and Norvig, Peter. Artificial
    Intelligence A Modern Approach, Section 20.5
    (736 48)

33
?? ???? ??? ????? ??????????
  • ???? ?????
  • ??????? ?????
  • ????? 1386
Write a Comment
User Comments (0)
About PowerShow.com