Activation
An activation is a numerical signal or intermediate representation produced by a neural-network unit or layer during computation.
Deep Learning with Python, Third Edition
The numeric value of a model activation.
- How it is used
- Uses activations to inspect how successive ConvNet layers transform images and to interpret learned filters.
- How deep it goes
- Defines activation tensors, visualizes individual channels, and optimizes filter responses, but does not survey every interpretation technique.
- Examples
- Uses a cat image, a sixth-channel edge visualization, complete activation grids, and optimized Xception filter patterns.
- What you can do after
- Diagnose/debug with it: extract, inspect, visualize, and optimize ConvNet activations to understand learned visual responses.
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Natural Language Processing in Action, Second Edition
A hidden layer activation is the numerical output produced by a neural-network unit or layer for a particular input state.
- How it is used
- Uses activations to carry an RNN’s accumulated interpretation of sequential text into processing subsequent tokens.
- How deep it goes
- Explains storage, sequential overwriting, and compact representation, but does not detail the underlying neuron equations.
- Examples
- Uses token sequences, evolving text encodings, and a paint-smudge analogy to illustrate activation values.
- What you can do after
- Evaluate how an RNN activation changes as each token contributes to the sequence representation.
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Deep Learning with R, Third Edition
An activation is the numerical output produced by a neural-network unit or layer for a given input.
- How it is used
- Uses activations to inspect how a convolutional network decomposes an input into learned features.
- How deep it goes
- Defines activations, extracts layer outputs, examines tensor shapes, and visualizes channels as feature maps.
- Examples
- Uses a held-out cat image, a 178 × 178 × 32 first-layer activation, individual channels, and complete activation grids.
- What you can do after
- Diagnose and interpret convolutional representations by extracting, inspecting, and plotting intermediate activations with Keras.
Read how Deep Learning with R, Third Edition explains activation →
Related concepts
- activation functionproduced by · An activation function maps a neural-network unit’s or layer’s input to an output, often introducing nonlinearity into the network’s computation.
- sparse autoencoderused by · A sparse autoencoder is an autoencoder trained to produce representations in which most encoded units are inactive or near zero.
- l2 normmeasured by · The L2 norm is the nonnegative Euclidean magnitude of a vector, equal to the square root of the sum of its components’ squares, and to absolute value for a scalar.
- neuronproduced by · A neuron is a computational unit in a neural network that transforms inputs, typically using learned parameters and an activation function, to produce an output.
- Swishincludes · Swish, also called SiLU, is a smooth neural-network activation function defined as x multiplied by the sigmoid of βx.
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