Target Encoder Adaptation Using Synchronized Discriminator Weights

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Solution Overview

Problem

Existing domain adaptation methods face challenges in adapting models from a source domain to a target domain due to differences in data distributions, known as domain shift, which affects the performance of machine learning models in real-world applications.

Innovation Solution

The approach initializes a target encoder and discriminator based on a source encoder and discriminator, using a first algorithm trained on labelled data, and synchronizes their weights through a local loss function mechanism, allowing the target encoder to adapt to the target domain while the source encoder remains fixed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If domain adaptation is performed to adapt models from source domain to target domain, then model performance under varying data distributions is improved, but computational complexity and training time increase

Engineering Contradiction:
Improvemodel performanceVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The domain adaptation process is segmented into distinct phases: initialization phase where target encoder and discriminator are set up based on source models, training phase where they are trained using local loss functions, and synchronization phase where weights are aligned. This segmentation allows manageable computation at each stage rather than requiring complete retraining.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The target encoder and discriminator are preliminarily initialized using pre-trained source encoder and discriminator weights before actual domain adaptation training begins. This preliminary action provides a strong starting point that reduces the computational burden of subsequent adaptation training.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If complete retraining is performed to adapt to target domain, then model accuracy is improved, but training time and computational resources increase

Engineering Contradiction:
Improvemodel accuracyVSAvoidtraining time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

Instead of complete retraining, the method applies partial action by training only the target encoder and target discriminator with domain adaptation objectives. The source encoder remains fixed, and only specific components are updated, significantly reducing training time while maintaining accuracy improvements.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The method changes parameters selectively by updating weights of target encoder and target discriminator while keeping source encoder weights fixed. Weight synchronization is performed periodically rather than continuously, optimizing the balance between adaptation accuracy and training efficiency.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If domain adaptation is applied to handle data distribution differences, then model robustness is improved, but additional training requirements increase

Engineering Contradiction:
Improvemodel robustnessVSAvoidtraining efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The target discriminator is trained to distinguish between source and target domain features, and the target encoder is trained to minimize this discrimination. This self-service mechanism allows the model to automatically adapt to domain shifts without requiring manual intervention or additional annotated target domain data.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The method employs feedback through local loss functions that provide continuous signals during training. The target discriminator provides feedback on domain differences, and the target encoder uses this feedback to adjust its features, creating a closed-loop adaptation process that improves robustness efficiently.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11664820B2Domain adaptation
Publication Date: 2023.05.30 NOKIA TECHNOLOGIES OY
  • US11664820B2 patent drawing
  • US11664820B2 patent drawing
  • US11664820B2 patent drawing

AI summary

An apparatus, method and computer program is described comprising: initialising weights of a target encoder based on a source encoder; initialising weights of a target discriminator associated with the target encoder such that the target discriminator is initialised to match a source discriminator associated with the source encoder; applying some of a target data set to the target encoder to generate target encoder outputs; applying the target encoder outputs to the target discriminator to generate a first local loss function output; training the target encoder to seek to increase the first local loss function output; training the target discriminator to seek to decrease the first local loss function output; and synchronising weights of the target discriminator and the source discriminator.