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Questions tagged [som]

A self-organizing map (SOM) is a type of artificial neural network that is trained using unsupervised learning to produce a map reprensenting the input space of the training samples.

A self-organizing map (SOM) is a type of artificial neural network that is trained using unsupervised learning to produce a map representing the input space of the training samples. Also, some supervised and semi-supervised SOMs exist.

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How do I make a U-matrix?

How exactly is an U-matrix constructed in order to visualise a self-organizing-map? More specifically, suppose that I have an output grid of 3x3 nodes (that have already been trained), how do I construct a U-matrix from this? You can e.g. assume…
Spacey
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What is the difference between SOM (Self Organizing Maps) and K-Means?

There is only one question related to this in stackoverflow, and it is more about which one is better. I just dont really understand the difference. I mean they both work with vectors, which are assigned randomly to clusters, they both work with the…
Oliver Hoffman
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Interpreting a Self Organizing Map

I have been doing reading about Self Organizing Maps, and I understand the Algorithm(I think), however something still eludes me. How do you interpret the trained network? How would you then actually use it for say, a classification task(once you…
Jack H
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Identify clusters in SOM (Self Organizing Map)

Once I have collected and organized data in a SOM how do I identify clusters? (Items are aggregated and clustered using many traits - upwards of 10) Specifically I want to find the 'center' of the cluster - therefor giving me the 'center' node(s).
Tyler Wall
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MATLAB: Self-Organizing Map (SOM) clustering

I'm trying to cluster some images depending on the angles between body parts. The features extracted from each image are: angle1 : torso - torso angle2 : torso - upper left arm .. angle10: torso - lower right foot Therefore the input data is a…
tguclu
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Self Organizing Maps in Mathematica (SOMs)

Does anybody know of, or have, a reasonable implementation of SOMs in Mathematica?
Richard Palmer
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Self Organizing Map (SOM) Implementation

I'm looking for a C, C++ or Java based SOM implementation with licensing applicable for commercial use (non-zero cost is okay). So far I'm aware that there exists SOM_PAK (from Kohonen), but the licensing forbids commercial use. Is anyone aware of…
Mark Elliot
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Error plotting Kohonen maps in R?

I was reading through this blog post on R-bloggers and I'm confused by the last section of the code and can't figure it out. http://www.r-bloggers.com/self-organising-maps-for-customer-segmentation-using-r/ I've attempted to recreate this with my…
James Willcox
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Convergence criterion for (batch) SOM (Self-Organizing Map, aka "Kohonen Map")?

I like to stop the execution when Batch SOM becomes converged. What error function can I use to determine the convergence?
S.N
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R package Kohonen - how to plot hexagons instead of circles as in Matlab SOM toolbox?

Is it possible to plot the SOM map (package Kohonen) with hexagons as elementary forms instead of circles? Now the different plottings (count, changes etc.) are plotted as circles with white surroundings. The aim is to create SOM visuals similar…
user2968765
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Is it right to normalize data and/or weight vectors in a SOM?

So I am being stumped by something that (should) be simple: I have written a SOM for a simple 'play' two-dimensional data set. Here is the data: You can make out 3 clusters by yourself. Now, there are two things that confuse me. The first is…
Spacey
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Efficient implementation of SOM (Self organizing map) on Pyspark

I am struggling with the implementation of a performant version of a SOM Batch algorithm on Spark / Pyspark for a huge dataset with > 100 features. I have the feeling that I can either use RDDs where I can/have to specifiy the parallization on my…
MosbyT
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Dimensionality Reduction using Self Organizing Maps

I have been working on Self Organizing Maps(SOM) for the past few months.But I still have some confusions in understanding the dimensionaliy reduction part.Can you suggest any simple method to understand the real working of SOMs on any real world…
Pooja
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Clustering through SOM

I have data of 71 attributes and 17 instances. I want to classify them into six groups or classes. I tried with newsom( data, [ 6 6 ] ). The result are shown in below figures. I can not figure out where the clusters are located and how I can…
user1900559
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Why is there a need for the number of iterations in the Self-Organizing Map?

:) While I was defending my thesis proposal, one of my professors asked me why do we have to specify the number of iterations in SOM? He said, there should've been a convergence criterion for us to stop training. However, I understand that we do not…
Chester
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