title: What's the difference between Conv layer and Pooling layer in CNN?
body: <p>Pooling can be considered as convolution whether it's max/average, right?</p>
  
  <p>The difference is that conv has parameters for optimization, but pooling doesn't, right? - e.g. the weights that filter in pooling has are not changed during learning.</p>
  
  <p>I'd also like to know what's the difference between <strong>the aims</strong> of conv and pooling.</p>
  
  <p>Why do we use each layers?
  What'll happen, if we don't use each layers?</p>