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# Data Applied:Similarity

## by dataapplied content, Datamining at DMT on Mar 06, 2010

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Data Applied:Similarity

Data Applied:Similarity

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## Data Applied:SimilarityPresentation Transcript

• Data-Applied.com: Similarity
• Introduction
Visualization of data having high dimensions is very difficult
The kohonen network enables us to represent high dimensional data in lower dimensions while keeping the topological information in it like similarity etc. intact
Kohonen networks or self organizing maps learn to classify data without supervision unlike artificial neural networks
A SOM does not need a target output to be specified unlike many other types of network. The learning steps are:
• Components of Kohonen network
Kohonen networks consist of:
Input nodes which are equal in number to the dimension of the data
A grid of nodes which are used for classification, each having a weight vector equal to the dimension of input and connected to all inputs
• Learn Algorithm Overview
Each node's weights are initialized.
A vector is chosen at random from the set of training data and presented to the lattice.
Every node is examined to calculate which one's weights are most like the input vector. The winning node is commonly known as the Best Matching Unit (BMU).
The radius of the neighbourhood of the BMU is now calculated. This is a value that starts large, typically set to the 'radius' of the lattice,  but diminishes each time-step. Any nodes found within this
• Learn Algorithm Overview
Each node's weights are initialized.
A vector is chosen at random from the set of training data and presented to the lattice.
Every node is examined to calculate which one's weights are most like the input vector. The winning node is commonly known as the Best Matching Unit (BMU).
The radius of the neighbourhood of the BMU is now calculated. This is a value that starts large, typically set to the 'radius' of the lattice,  but diminishes each time-step. Any node found within
• Learn Algorithm Overview(contd..)
radius are deemed to be inside the BMU's neighbourhood.
5. Each neighbouring node's (the nodes found in step 4) weights are adjusted to make them more like the input vector. The closer a node is to the BMU, the more its weights get altered.
6. Repeat step 2 for N iterations.
• Similarity using Data Applied’s web interface
• Step1: Selection of data
• Step2: Selecting Similarity
• Step3: Result
• Visit more self help tutorials
• Pick a tutorial of your choice and browse through it at your own pace.
• The tutorials section is free, self-guiding and will not involve any additional support.
• Visit us at www.dataminingtools.net