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Competitive learning :-
Competitive learning is a form of unsupervised learning in artificial neural networks, in which nodes compete for the right to respond to a subset of the input data.
A variant of Hebbian learning, competitive learning works by increasing the specialization of each node in the network. It is well suited to finding clusters within data.
Models and algorithms based on the principle of competitive learning include vector quantization and self-organizing maps.
In a competitive learning model, there are hierarchical sets of units in the network with inhibitory and excitatory connections.
The excitatory connections are between individual layers and the inhibitory connections are between units in layered clusters.
Units in a cluster are either active or inactive.
There are three basic elements to a competitive learning rule :
A set of neurons that are all the same except for some randomly distributed synaptic weights, and which therefore respond differently to a given set of input patterns.
A limit imposed on the “strength” of each neuron.
A mechanism that permits the neurons to compete for the right to respond to a given subset of inputs, such that only one output neuron (or only one neuron per group), is active (i.e., “on”) at a time. The neuron that wins the competition is called a “winner-take-all” neuron.