Domain Adaptation With Multi-Discriminator CycleGAN for Scarce Data

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Solution Overview

Problem

Existing domain adaptation methods, particularly in speech recognition, face challenges when adapting from a source domain with abundant data to a target domain with scarce data, leading to sub-optimal mappings due to limited unsupervised training data and restrictive cycle-consistency constraints.

Innovation Solution

The implementation of a multi-discriminator CycleGAN with an augmented cyclic adversarial learning model that uses multiple discriminator models corresponding to domain variable bands to perform discrimination, along with a task-specific model to enforce a relaxed cycle-consistency constraint, facilitating better domain adaptation in low-resource settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional domain adaptation methods are used with limited target domain data, then the model can be trained with available data, but the learned mapping between domains becomes sub-optimal

Engineering Contradiction:
Improvemapping qualityVSAvoidtraining data volume
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent introduces an adversarial domain classifier as an intermediary component that learns to distinguish between source and target domain features. This classifier acts as a mediator that guides the feature extractor to create domain-invariant representations, enabling effective domain adaptation even with limited target domain data by leveraging the adversarial training mechanism to bridge the domain gap.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs parameter sharing and freezing strategies where the feature extractor parameters are pre-trained on source domain data and then frozen or fine-tuned with limited target domain data. This parameter change approach allows the model to leverage source domain knowledge while adapting to target domain characteristics, improving mapping quality without requiring extensive target domain training data.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If cycle-consistency constraints are enforced in domain adaptation, then the mapping learns to preserve information, but the constraint becomes too restrictive with scarce data

Engineering Contradiction:
Improveinformation preservationVSAvoidconstraint complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts and removes the restrictive cycle-consistency constraint from the domain adaptation framework. By taking out this overly complex constraint, the model avoids the problems of over-constraint that plague traditional cycleGAN approaches when applied to domain adaptation with limited data, while still maintaining information preservation through the adversarial training objective.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of enforcing cycle-consistency to preserve information (the traditional approach), the patent inverts the approach by using adversarial domain classification to achieve domain invariance. This inversion allows the model to learn robust mappings without being constrained by the restrictive cycle-consistency requirement, particularly beneficial when target domain data is scarce.

Inventive Principle:
Principle #13The other way round (Inversion)

3Measurement precision

If multiple discriminator models are used to perform discrimination on domain variable bands, then the learning of mappings between domains is enhanced, but the model complexity increases

Engineering Contradiction:
Improvedomain discrimination accuracyVSAvoidmodel structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the domain discrimination task by introducing multiple discriminator models, each responsible for specific domain variable bands or aspects. This segmentation allows for more precise domain adaptation by targeting specific sources of domain variation, improving measurement precision in distinguishing domain characteristics while distributing the complexity across multiple specialized components rather than one monolithic discriminator.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11676022B2Systems and methods for learning for domain adaptation
Publication Date: 2023.06.13 SALESFORCE INC
  • US11676022B2 patent drawing
  • US11676022B2 patent drawing
  • US11676022B2 patent drawing

AI summary

A method for training parameters of a first domain adaptation model. The method includes evaluating a cycle consistency objective using a first task specific model associated with a first domain and a second task specific model associated with a second domain, and evaluating one or more first discriminator models to generate a first discriminator objective using the second task specific model. The one or more first discriminator models include a plurality of discriminators corresponding to a plurality of bands that corresponds domain variable ranges of the first and second domains respectively. The method further includes updating, based on the cycle consistency objective and the first discriminator objective, one or more parameters of the first domain adaptation model for adapting representations from the first domain to the second domain.