som of soms

Intelligent Database Systems Lab

國立雲林科技大學National Yunlin University of Science and Technology

SOM of SOMs

Presenter : Cheng-Feng Weng

Authors :Tetsuo Furukawa

2009/07/09

NN.16 (2009)

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Outline

Motivation Objective Method Experiments Conclusion Comments

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Motivation

The SOM provides a map of data vectors, but not a map of class distributions.

Class confusion

Attribute

X

Y

Z

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linear manifold

Motivation (cont.)

Manifold can be seen a class distributions.

viewpoint manifold

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Objective

The paper is to propose a method of mapping class called SOMs that can represent the relationships between distributions.

The manifold gradually changes shape.

15 classes

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The SOMs

It is a hierarchical structure of a set of child SOMs and a single parent SOM.

Bottle up

Manifold

Class distributions

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The SOMs algorithm

1. There are J child SOMs and a parent SOM map.

2. Children and parent maps have own parameters.

3. Randomize parent SOM map, and use least qe map to replace child’s.

4. Class maps are estimated for each class dataset.

5. The BMMs are regarded as data vectors for parent map.

6. Update child’s weights by overwriting its BMM.

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An Example for the SOMs

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Experiments

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Experiments (cont.)

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Application to autonomous mobile robot

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Conclusion

The essence of the algorithm is to generate a higher rank of data representation with class information as a clue, and the given datasets are modeled by fitting to a fiber bundle.

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Comments

Advantage From a class point of view Inversed construction

Drawback …

Application Class manifold LDA + SOM vs. SOM + LVQ