Finding binary codes for documents
 2000  reconstructed counts
• Train an auto-encoder using 30
logistic units for the code layer.
• During the fine-tuning stage, add
noise to the inputs to the code
units.
– The “noise” vector for each
training case is fixed. So we
still get a deterministic gradient.
– The noise forces their activities
to become bimodal in order to
resist the effects of the noise.
– Then we simply round the
activities of the 30 code units to
1 or 0.
500 neurons
250 neurons
30
noise
250 neurons
500 neurons
     2000  word counts