Reservoir Computing Node Diversity via Segmented Delay Paths

Solution Overview

Problem

Reservoir computing using a delayed feedback system has limited node diversity, which restricts computation ability due to its simple network configuration.

Innovation Solution

A device with a reservoir layer that includes an input unit, a nonlinear converter, and an output unit connected via a delay mechanism, where the nonlinear converter performs nonlinear conversion on a signal and the output unit generates a signal with different delay times, enhancing node diversity and computation ability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a simple delay loop configuration is used in reservoir computing, then the device complexity is reduced and ease of manufacture is improved, but the node diversity is limited and computation ability deteriorates

Engineering Contradiction:

Improveease of manufactureVSAvoidnode diversity

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The delay loop is segmented into multiple parallel delay paths with different delay times (τ1, τ2, ..., τn). Each path processes the signal with a unique delay, creating diverse node states without complicating the overall device structure. This segmentation allows the system to achieve high node diversity while maintaining manufacturing simplicity through modular path construction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces a time-dimension diversity by varying delay times across parallel paths. Instead of adding spatial complexity with more interconnected nodes, the system exploits the time dimension by creating signals with different temporal characteristics. This dimensional approach enhances computation ability without proportionally increasing device complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If a simple delay loop configuration is used in reservoir computing, then the device complexity is reduced, but the computation ability deteriorates due to limited node diversity

Engineering Contradiction:

Improvedevice complexityVSAvoidcomputation ability

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The delay loop is segmented into multiple parallel delay paths with different delay times (τ1, τ2, ..., τn). Each path processes the signal with a unique delay, creating diverse node states without complicating the overall device structure. This segmentation allows the system to achieve high node diversity while maintaining manufacturing simplicity through modular path construction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces a time-dimension diversity by varying delay times across parallel paths. Instead of adding spatial complexity with more interconnected nodes, the system exploits the time dimension by creating signals with different temporal characteristics. This dimensional approach enhances computation ability without proportionally increasing device complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If multiple parallel delay paths with different delay times are introduced, then the node diversity and computation ability are improved, but the device complexity increases

Engineering Contradiction:

Improvenode diversityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple parallel delay paths are merged into a single reservoir layer structure where all paths share common input and output connections. The nonlinear conversion unit receives signals from all delay paths and integrates them into a unified output. This merging approach allows the system to benefit from diverse delay characteristics while avoiding the complexity of fully interconnected multi-path architectures.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The parallel delay paths are designed with universal characteristics where each path performs the same basic function (delaying the signal) but with different delay parameters. This universality allows the system to achieve high node diversity through parameter variation rather than structural complexity, maintaining ease of manufacture while improving computation ability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11423299B2Device and computer realizing calculation of reservoir layer of reservoir computing

Publication Date: 2022.08.23 HITACHI LTD

AI summary

A device includes an input unit, a nonlinear converter, and an output unit. The nonlinear converter and the output unit are connected via a connection path having a delay mechanism that realizes a feedback loop giving a delay to a signal. The delay mechanism includes a conversion mechanism that generates a plurality of signals with different delay times using the signal output from the nonlinear converter, generates a new signal by superimposing the plurality of signals, and outputs the generated signal to the output unit.