title: Online training in convolutional neural network
body: <p>In <a href="https://arxiv.org/pdf/1503.03832.pdf" rel="nofollow noreferrer">this</a> article the neural network is trained <strong>online</strong> - the input is selected during training:</p>
  
  <blockquote>
    <p>This can be done by selecting the hard
    positive/negative exemplars from within a mini-batch.</p>
  </blockquote>
  
  <p>Can someone explain online training in detail? </p>