Dual Channel Network for Multivariate Time Series Retrieval

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Solution Overview

Problem

Conventional time series retrieval methods fail to account for static system statuses, which are essential in determining system behavior, leading to inaccurate results as they only consider dynamic time series data.

Innovation Solution

A dual-channel network is introduced, combining a Multi-Layer Perceptron (MLP) based static encoder with a Recurrent Neural Network (RNN) based temporal encoder, jointly trained using metric learning loss to encode time series segments with static statuses into compact binary codes, enabling effective multivariate time series retrieval.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional time series retrieval methods are used that only consider dynamic time series data, then the retrieval process is simple, but the retrieval accuracy deteriorates because static system statuses are not accounted for

Engineering Contradiction:
Improveretrieval accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the encoding process into two distinct channels: a static status encoder that processes static system statuses, and a temporal encoder that processes dynamic time series data. These two encoders work in parallel and their outputs are combined to form a comprehensive representation, allowing the system to capture both static and dynamic characteristics without overwhelming complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the outputs of the static status encoder and temporal encoder by concatenating their respective feature vectors. This combined representation is then passed through a binary code extractor to generate binary codes that encode both static and dynamic information, achieving accurate retrieval while managing complexity through efficient feature fusion

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If binary codes are generated to preserve relative similarity relations, then retrieval efficiency is improved, but information loss may occur during the encoding process

Engineering Contradiction:
Improveretrieval efficiencyVSAvoidinformation loss
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The system transforms continuous feature vectors from the encoders into discrete binary codes through a binary code extractor. This parameter transformation enables efficient similarity search using Hamming distance while the metric learning loss function ensures that the binary codes preserve relative similarity relationships, minimizing information loss during the discretization process

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional continuous-space similarity computation with discrete binary code comparison using Hamming distance. This substitution dramatically improves retrieval efficiency by enabling bitwise operations instead of computationally intensive continuous vector comparisons, while metric learning ensures the binary representation maintains similarity relationships

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If metric learning loss is used for joint training, then the preservation of relative similarity is improved, but training complexity increases

Engineering Contradiction:
Improvesimilarity preservationVSAvoidtraining complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The metric learning loss function provides feedback during training by computing the difference between predicted similarity (based on binary code Hamming distance) and actual similarity (based on ground truth labels). This feedback gradient guides the optimization of both static status encoder and temporal encoder parameters, ensuring they learn to produce binary codes that preserve relative similarity relationships

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The metric learning loss function serves multiple purposes: it trains both encoders simultaneously, ensures binary codes preserve similarity relationships, and enables end-to-end optimization of the entire retrieval system. This multi-functional loss formulation manages training complexity by unifying the optimization objective across different components

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS20230267305A1Dual channel network for multivariate time series retrieval with static statuses
Publication Date: 2023.08.24 NEC CORP
  • US20230267305A1 patent drawing
  • US20230267305A1 patent drawing
  • US20230267305A1 patent drawing

AI summary

A computer implemented method is provided. The method includes jointly encoding, by a dual-channel feature extractor, a current time series segment with corresponding static statuses into a compact feature. The method further includes converting, by a binary code extractor, the compact feature into a binary code. The method also includes computing distances between the binary code and all binary codes stored in a binary code database. The method additionally includes retrieving the top relevant multivariate time series segments based on the distances.