Hebb's Postulate of Learning Biological formulation ● When an axon of cell A is near enough to excite a cell and repeatedly or persistently takes part in firing it,some growth process or metabolic change takes place in one or both cells such that A's efficiency as one of the cells firing B is increased. △WB,A F(yB,A) 09/07/2023 Artificial Neural Networks-I 16
09/07/2023 Artificial Neural Networks - I 16 Hebb’s Postulate of Learning • Biological formulation • When an axon of cell A is near enough to excite a cell and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency as one of the cells firing B is increased
赫布律 。 当细胞A的一个轴突和细胞B很近，足以对它产 生影响，并且持久地、不断地参与了对细胞B的 兴奋，那么在这两个细胞或其中之一会发生某 种生长过程或新陈代谢变化，以致于A作为能使 B兴奋的细胞之一，它的影响加强了。 09/07/2023 Artificial Neural Networks-I 17
09/07/2023 Artificial Neural Networks - I 17 赫布律 • 当细胞A的一个轴突和细胞B 很近，足以对它产 生影响，并且持久地、不断地参与了对细胞B 的 兴奋，那么在这两个细胞或其中之一会发生某 种生长过程或新陈代谢变化，以致于A作为能使 B 兴奋的细胞之一，它的影响加强了
Hebb's Postulate:revisited Stent (1973),and Changeux and Danchin(1976) have expanded Hebb's rule such that it also mo- ● dels inhibitory synapses: 1.If two neurons on either side of a synapse are activated simultaneously(synchronously),then the strength of that synapse is selectively increased. 2.If two neurons on either side of a synapse are activated asynchronously,then that synapse is selectively weakened or eliminated. 09/07/2023 Artificial Neural Networks-I 18
09/07/2023 Artificial Neural Networks - I 18 Hebb’s Postulate: revisited • Stent (1973), and Changeux and Danchin (1976) • have expanded Hebb’s rule such that it also mo- • dels inhibitory synapses: 1. If two neurons on either side of a synapse are activated simultaneously (synchronously), then the strength of that synapse is selectively increased. 2. If two neurons on either side of a synapse are activated asynchronously, then that synapse is selectively weakened or eliminated
Artificial Neural Networks T 1 Output layer fully connected Hidden layers 999 Input layer sparsely connected 9 09/07/2023 Artificial Neural Networks-I 19
09/07/2023 Artificial Neural Networks - I 19 Artificial Neural Networks Output layer Input layer Hidden layers fully connected sparsely connected
Feedforward ANN Architectures Information flow unidirectional 。Static mapping:y-几 Multi-Layer Perceptron (MLP) Radial Basis Function(RBF) Kohonen Self-Organising Map (SOM) 09/07/2023 Artificial Neural Networks-I 20
09/07/2023 Artificial Neural Networks - I 20 Feedforward ANN Architectures • Information flow unidirectional • Static mapping: y=f(x) • Multi-Layer Perceptron (MLP) • Radial Basis Function (RBF) • Kohonen Self-Organising Map (SOM)