Vector quantization of images based upon the kohonen self-organization feature maps

1988 ◽  
Vol 1 ◽  
pp. 518 ◽  
Author(s):  
Nasser M. Nasrabadi ◽  
Yushu Feng
Author(s):  
Mu-Chun Su ◽  
◽  
Eugene Lai ◽  
Chee-Yuen Tew ◽  
Chih-Wen Liu ◽  
...  

In recent years, many significant research efforts have been devoted to voltage security margins which show how close the current operating point of a power system is to a voltage collapse point as assessment of voltage security. In this paper we propose a technique based on the SOM-based fuzzy systems for voltage security margin estimation. The SOM-based fuzzy systems use the Kohonen’s self-organizing feature map (SOM) algorithm, not only for its vector quantization feature, but also for its topological property. The vector quantization feature of feature maps is used to search a good supply of most representative cluster centers. Then the topology-preserving feature is fully utilized to select a set of most influential rules so as to contribute to the computation of system outputs. The proposed technique was tested on 1604 simulated data randomly generated from operating conditions on the IEEE 30-bus system to indicate its high efficiency.


2001 ◽  
Vol 13 (3) ◽  
pp. 563-593 ◽  
Author(s):  
James R. Williamson

This article proposes a neural network model of supervised learning that employs biologically motivated constraints of using local, on-line, constructive learning. The model possesses two novel learning mechanisms. The first is a network for learning topographic mixtures. The network's internal category nodes are the mixture components, which learn to encode smooth distributions in the input space by taking advantage of topography in the input feature maps. The second mechanism is an attentional biasing feedback circuit. When the network makes an incorrect output prediction, this feedback circuit modulates the learning rates of the category nodes, by amounts based on the sharpness of their tuning, in order to improve the network's prediction accuracy. The network is evaluated on several standard classification benchmarks and shown to perform well in comparison to other classifiers.


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