Winner-take-all (computing)

Output nodes in the network mutually inhibit each other, while simultaneously activating themselves through reflexive connections.

After some time, only one node in the output layer will be active, namely the one corresponding to the strongest input.

Thus the network uses nonlinear inhibition to pick out the largest of a set of inputs.

Winner-take-all is a general computational primitive that can be implemented using different types of neural network models, including both continuous-time and spiking networks.

[1][2] Winner-take-all networks are commonly used in computational models of the brain, particularly for distributed decision-making or action selection in the cortex.

[4][5] They are also common in artificial neural networks and neuromorphic analog VLSI circuits.

[7] This rule is unsupervised, since we need just the input vector, not a reference output.

[8] A simple, but popular CMOS winner-take-all circuit is shown on the right.

This circuit was originally proposed by Lazzaro et al. (1989)[9] using MOS transistors biased to operate in the weak-inversion or subthreshold regime.

In addition, the bias current IBIAS is set by a single global transistor that is common to all the inputs.

The largest of the input currents sets the common potential VC.

Thus, the circuit selects the larger of the two input currents, i.e., if IIN,1 > IIN,2, we get IOUT,1 = IBIAS and IOUT,2 = 0.

A SPICE-based DC simulation of the CMOS winner-take-all circuit in the two-input case is shown on the right.

As shown in the top subplot, the input IIN,1 was fixed at 6nA, while IIN,2 was linearly increased from 0 to 10nA.

In stereo matching algorithms, following the taxonomy proposed by Scharstein and Szelliski,[10] winner-take-all is a local method for disparity computation.

Adopting a winner-take-all strategy, the disparity associated with the minimum or maximum cost value is selected at each pixel.

It is axiomatic that in the electronic commerce market, early dominant players such as AOL or Yahoo!

By 1998, one study[clarification needed] found the top 5% of all web sites garnered more than 74% of all traffic.

The winner-take-all hypothesis in economics suggests that once a technology or a firm gets ahead, it will do better and better over time, whereas lagging technology and firms will fall further behind.