Forecasting Irregular Time Series with Missing Values

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Solution Overview

Problem

Existing methods fail to effectively forecast future values in multivariate irregularly sampled time series data with missing values, as they do not account for the irregular sampling intervals and missing data points, leading to inaccurate predictions.

Innovation Solution

A processor uses a recurrent neural network, specifically gated recurrent units, to input non-missing values, mask values, and time interval values to predict missing values and forecast future data points, including the timing of next snapshots, by employing a custom loss function and imputation techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing forecasting methods are used on irregularly sampled time series data with missing values, then the method is simple to implement, but the forecasting accuracy deteriorates due to inability to account for irregular sampling intervals and missing data points

Engineering Contradiction:
Improveforecasting accuracyVSAvoidmethod complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-processing the time series data to extract and encode temporal characteristics (sampling intervals, missing value patterns, seasonality indicators) before feeding them to the forecasting model. This preprocessing step prepares the data in advance to account for irregular sampling and missing values, improving forecasting accuracy without requiring complex modifications to the core model architecture.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediary components including temporal encoding layers and attention mechanisms that act as mediators between the raw irregularly sampled data and the forecasting model. These intermediaries transform the irregular time series into a format suitable for standard forecasting architectures, bridging the gap between complex data characteristics and simpler model structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a recurrent neural network is used to capture long-term dependencies in irregularly sampled time series, then the forecasting accuracy improves, but the computational time and complexity increase

Engineering Contradiction:
Improveforecasting accuracyVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the time series processing into distinct components: temporal pattern extraction, seasonality detection, and trend analysis. By dividing the complex task of capturing long-term dependencies into separate modular components, the system achieves accurate forecasting while reducing overall computational burden through specialized efficient implementations of each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent leverages periodic action by detecting and exploiting seasonal patterns in the time series data. By identifying periodic components and using them to guide the forecasting process, the model can make accurate predictions about future values at corresponding seasonal points without requiring excessively long training sequences, thus reducing computational time while maintaining accuracy.

Inventive Principle:
Principle #19Periodic action

3Loss of information

If imputation techniques are applied to fill missing values in time series data, then the completeness of data improves, but the risk of introducing biased predictions increases

Engineering Contradiction:
Improvedata completenessVSAvoidprediction reliability
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent applies feedback by using the observed data patterns and temporal relationships to dynamically adjust imputation strategies. The model learns from the actual data distribution and uses this feedback to generate imputed values that are consistent with the underlying patterns, reducing bias introduction while maintaining data completeness. The feedback loop ensures imputed values align with observed behavior.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes parameters by adapting imputation methods based on local data characteristics rather than using fixed imputation rules. By adjusting imputation parameters dynamically according to the specific temporal context, seasonality, and missingness patterns, the system fills missing values in a way that preserves prediction reliability while achieving data completeness.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12050980B2Forecasting in multivariate irregularly sampled time series with missing values
Publication Date: 2024.07.30 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US12050980B2 patent drawing
  • US12050980B2 patent drawing
  • US12050980B2 patent drawing

AI summary

In an approach for forecasting in multivariate irregularly sampled time series, a processor receives time series data having one or more missing values. A processor determines, from the time series data, non-missing values present in the time series data. A processor determines, from the time series data, zero or more mask values for the time series data. A processor determines time interval values. A processor inputs the one or more missing values, the non-missing values, the zero or more mask values, and the time interval values into a recurrent neural network. A processor determines a predicted value for the one or more missing values.