KI2 - 7. Clustering Algorithms. Johan Everts. Kunstmatige Intelligentie / RuG. What is Clustering? .
Kunstmatige Intelligentie / RuG
Find K clusters (or a classification that consists of K clusters) so that the objects of one cluster are similar to each other whereas objects of different clusters are dissimilar. (Bacher 1996)
regardless of whether the data contains them
Agglomerative clustering treats each data point as a singleton cluster, and then successively merges clusters until all points have been merged into a single remaining cluster. Divisive clustering works the other way around.
In single-link hierarchical clustering, we merge in each step the two clusters whose two closest members have the smallest distance.
In complete-link hierarchical clustering, we merge in each step the two clusters whose merger has the smallest diameter.
The knee of a curve is defined as the point of maximum curvature.
Distance < Threshold
Distance > Threshold
The Self-Organizing Map (SOM) is an unsupervised artificial neural network algorithm. It is a compromise between biological modeling and statistical data processing
Learning rate & neighbourhood size
Distance related learning
mapping a 3D colorspace on a 2D Kohonen map