Experience Replay Encoder for Continual Learning

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Solution Overview

Problem

Existing learning systems face challenges in continual learning as they tend to forget previously learned tasks when adapting to new tasks, leading to decreased learning capacity and performance over time, particularly due to catastrophic forgetting issues.

Innovation Solution

A system that uses experience replay with a Generative Autoencoder to map tasks into a shared distribution in an embedding space, generating pseudo-data points for experience replay, allowing the system to adapt to new tasks without forgetting past knowledge by enforcing a shared distribution across tasks using sliced-Wasserstein distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If model consolidation is used to separate information pathways for different tasks, then catastrophic forgetting is reduced, but network learning capacity is compromised

Engineering Contradiction:
Improveretention of past tasksVSAvoidlearning capacity
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The network is segmented into task-specific pathways and a shared pathway. Task-specific pathways preserve knowledge for individual tasks while the shared pathway enables generalization. This segmentation allows the network to maintain performance on past tasks without compromising overall learning capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The architecture implements nesting by placing task-specific modules within a broader shared network structure. Each task-specific pathway is nested within the shared pathway, allowing hierarchical organization of knowledge where specific task knowledge is contained within the general learning framework.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If experience replay with memory buffer is used to store past experiences, then catastrophic forgetting is reduced, but system complexity and memory requirements increase

Engineering Contradiction:
Improveretention of past tasksVSAvoidmemory buffer complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the essential function of experience replay by removing the need for explicit memory buffers. Instead of storing and replaying actual past experiences, the system uses task-specific pathways that inherently preserve task distributions, extracting only the necessary memory function while eliminating buffer complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system creates copies of task-specific knowledge through separate pathways rather than copying actual data samples into a buffer. Each task-specific pathway maintains a representation of its task distribution, effectively copying the essential information without requiring storage of original experiences.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If generative models are used to produce pseudo-data points, then dependence on memory buffer is reduced, but mode collapse and hyper-parameter sensitivity increase

Engineering Contradiction:
Improveindependence from memory bufferVSAvoidstability of generative process
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Task-specific pathways act as intermediaries between the shared network and the task distributions. Rather than using complex generative models to produce pseudo-data, the task-specific pathways directly maintain and provide task representations, serving as a stable intermediary that eliminates mode collapse issues.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Each task-specific pathway serves itself by maintaining its own task distribution representation. The pathways are self-sufficient in preserving task knowledge without requiring external generative models or memory buffers, making the system more stable and less sensitive to hyper-parameters.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS11645544B2System and method for continual learning using experience replay
Publication Date: 2023.05.09 HRL LAB
  • US11645544B2 patent drawing
  • US11645544B2 patent drawing
  • US11645544B2 patent drawing

AI summary

Described is a system for continual learning using experience replay. In operation, the system receives a plurality of tasks sequentially, from which a current task is fed to an encoder. The current task has data points associated with the current task. The encoder then maps the data points into an embedding space, which reflects the data points as discriminative features. A decoder then generates pseudo-data points from the discriminative features, which are provided back to the encoder. The discriminative features are updated in the embedding space based on the pseudo-data points. The encoder then learns (updates) a classification of a new task by matching the new task with the discriminative features in the embedding space.