Underwater Acoustic Target Recognition With RNN Differential Learning Rates

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Solution Overview

Problem

Current UATR methods face challenges such as low signal-to-noise ratio, limited datasets, and complexity due to underwater acoustic data characteristics, which affect accuracy and reliability, especially in military applications where data confidentiality limits training data availability.

Innovation Solution

A UATR method using a recurrent neural network (RNN) structure and differential learning rate (LR) retraining, involving preprocessing, constructing a UATR depth model with a pre-trained model, and setting different LRs for the pre-training part and RNN structure to enhance feature extraction and classification accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a pre-trained model is used for UATR, then training data requirement is reduced, but model adaptability to underwater acoustic signals deteriorates

Engineering Contradiction:
Improvetraining data quantityVSAvoidmodel adaptability to underwater acoustic signals
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by differentiating learning rates for different model components. The pre-trained model parameters use a first learning rate while the RNN structure parameters use a second learning rate, allowing each component to be optimized independently for its specific function in the underwater acoustic signal processing task.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the model into two distinct parts: a pre-trained model component for feature extraction and an RNN structure component for temporal modeling. This segmentation allows each part to be trained and optimized separately, with the pre-trained model providing general acoustic features and the RNN providing task-specific temporal processing for underwater acoustic signals.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single learning rate is used for the entire model, then training simplicity is improved, but training efficiency and convergence deteriorate

Engineering Contradiction:
Improvetraining configuration complexityVSAvoidtraining efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies local quality by assigning different learning rates to different parts of the model based on their specific requirements. The pre-trained model uses a first learning rate optimized for its feature extraction capabilities, while the RNN structure uses a second learning rate optimized for temporal pattern learning, allowing each component to converge at the appropriate speed.

Inventive Principle:
Principle #3Local quality

3Speed

If the pre-trained model is fine-tuned with high learning rate, then convergence speed is improved, but model stability and feature preservation deteriorate

Engineering Contradiction:
Improveconvergence speedVSAvoidmodel stability and feature preservation
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent uses parameter changes by setting a first learning rate for the pre-trained model that is lower than the second learning rate for the RNN structure. This differentiated approach allows the pre-trained model to preserve its stable features while still adapting to the new task, preventing excessive updates that would destabilize the model.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250217622A1Underwater acoustic target recognition (UATR) method based on recurrent neural network (RNN) structure and differential learning rate (LR) retraining
Publication Date: 2025.07.03 HANGZHOU DIANZI UNIV
  • US20250217622A1 patent drawing
  • US20250217622A1 patent drawing
  • US20250217622A1 patent drawing

AI summary

Provided is an underwater acoustic target recognition (UATR) method based on a recurrent neural network (RNN) structure and differential learning rate (LR) retraining, which is specifically aimed at identification and classification issues of ship underwater acoustic targets. Specific implementation steps include: 1. A ship underwater acoustic signal is preprocessed. 2. A UATR depth model is constructed based on a pre-trained model. 3. Retraining configuration. 4. The model is retrained to implement migration to a target domain. 5. A high-performance classification model for UATR is trained. In a model structure of this application, the pre-trained model is combined with the newly added RNN structure and a classification layer, so that a model obtained after retraining can more accurately identify an underwater acoustic target.