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| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| data_mining:neural_network:perceptron [2017/02/03 23:17] – [What perceptrons can't do] phreazer | data_mining:neural_network:perceptron [2017/02/03 23:21] (current) – [What perceptrons can't do] phreazer | ||
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| Pos and neg cases can not be seperated by a plane => not linearly separable. | Pos and neg cases can not be seperated by a plane => not linearly separable. | ||
| + | === Discriminate patterns under translation with wrap-around === | ||
| + | |||
| + | Binary threshold neuron can't discriminate between different patterns that have same number of on pixels (if pattern can translate with wrap-around). | ||
| + | |||
| + | Proof: | ||
| + | |||
| + | Pattern A on all possible translations (4 on pixels). | ||
| + | Total Input will be 4x sum of all the weights. | ||
| + | |||
| + | Pattern B on all possible translations (4 on pixels) | ||
| + | Total Input will be 4x sum of all the weights. | ||
| + | |||
| + | But every single case of pattern A must provide more import than all single cases of pattern B. | ||
| Case: | Case: | ||