Glossario IA
Il dizionario completo dell'Intelligenza Artificiale
Echo State Network
Recurrent neural network architecture where only the output layer is trained, with the reservoir remaining fixed and random.
Reservoir
Collection of untrained recurrent neurons generating a rich and non-linear representation of the system's input history.
Echo state
Fundamental condition where the current reservoir states asymptotically depend only on recent past inputs and not on initial conditions.
Spectral radius
Maximum eigenvalue in magnitude of the reservoir weight matrix, controlling the memory dynamics and fade-out of the network.
Echo property
Essential characteristic ensuring that the influence of initial conditions disappears exponentially in favor of the input history.
Readout layer
Trainable linear output layer combining reservoir states to generate the final network prediction.
Reservoir computing
Computational paradigm using a fixed dynamic reservoir to project data into a high-dimensional space before classification.
Leaky integration
Mechanism controlling the update speed of reservoir states through a leak parameter between 0 and 1, adjusting temporal memory.
Reservoir connectivity
Density of non-zero connections in the reservoir weight matrix, typically low (1-10%) to ensure network sparsity.
Input matrix
Fixed weight matrix projecting input signals into the high-dimensional space of the reservoir with a controlled input scale.
Internal states
Vector of reservoir neuron activations at a given time, encapsulating the past temporal information of the system.
Input noise
Random perturbation added to inputs to improve reservoir robustness and avoid unwanted attractors in the dynamics.
Linear regression
Optimization method used to calculate output weights by minimizing the squared error between predictions and targets.
Memory capacity
Quantitative measure of the reservoir's ability to retain and retrieve information over varying time delays in inputs.
Time scale
Parameter determining the effective temporal memory window of the reservoir, controlled by the spectral radius and leak rate.
Chaotic dynamics
Operational regime of the reservoir where the spectral radius > 1, generating complex dynamics sensitive to initial conditions.