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Transformer

Reference​

Sequence to Sequence (Seq2Seq)​

  • Transformer is a type of Seq2Seq model.

Application​

  1. Seq2Seq for multi label classification An object can belong to multiple classes.
  2. Seq2Seq for Syntatic Parsing
  3. Deep Learning for human language Processing
  4. Seq2Seq for Object Detection

Architecture​

Encoder​

  • RNN, CNN, and Self-Attention are all viable choices for model encoders.
  • Input: sequence of vectors
  • Output: sequence of vectors

Transformer Encoder Architecture​

  • Simplified Transformer Encoder Architecture

Residual​

Problem: Vanishing gradients in deep networks. Solution: Add skip connections to allow gradients to flow through the network.

Decoder​

Decoders can be broadly categorized into two types: Autoregressive and Non-Autoregressive.

  • Autogressive decoder: one by one eating words and output

  • Non-Autoregressive decoder: all words at once

"Masked" Self-Attention​

只考慮之前的,因為之後的根本沒產生。

Encoder-Decoder 連接處​

Cross-Attention​

info

待完成

Training Tip​

Teacher Forcing​

  • 先標記 -> 計算 cross-entropy loss(one-hot vector vs real probability distribution)
  • Training 時直接強迫輸出正確答案

Copy Mechanism​

  • Pointer Network

Guided Attention​

  • Monotonic Attention, Location-aware Attention
  • 在speech Recognition,TTS 上可能很重要
  • In some tasks, input and output are monotonically aligned.