Prediction Function Creation Device for Missing Value Patterns

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Solution Overview

Problem

Existing prediction systems face reduced accuracy when dealing with a large number of variations in missing values for explanatory variables, as the increased number of labels results in smaller sample sizes for training, leading to lower prediction function accuracy.

Innovation Solution

A prediction function creation device and method that clusters samples based on patterns of missing values, assigns weights to these clusters, and uses partial training data to determine relevant explanatory variables for creating prediction functions tailored to each pattern of missing values, thereby increasing the sample size for each prediction function and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If machine learning methods are applied to training data with missing explanatory variable values, then prediction accuracy can be improved, but the methods become inapplicable when missing values are present

Engineering Contradiction:
Improveprediction accuracyVSAvoidapplicability to data with missing values
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent converts the harmful effect of missing values (which make machine learning inapplicable) into a beneficial classification feature. By clustering samples based on their missing value patterns and treating these patterns as meaningful categories, the system enables machine learning to process and utilize data that would otherwise be unusable, thereby improving both applicability and prediction accuracy

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If missing values are imputed by mean value or predicted from other variables, then the data can be processed by machine learning, but unnecessary errors are introduced in the prediction

Engineering Contradiction:
Improveprocessability of data with missing valuesVSAvoidprediction accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the training data into distinct groups based on missing value patterns, creating separate subsets for each pattern type. This segmentation allows the system to apply appropriate processing to each group without introducing erroneous imputations, as each segment is handled according to its specific characteristics rather than applying a uniform imputation method that would propagate errors

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If data is partitioned by missing manner with each unique pattern receiving a separate label, then machine learning can be applied to each partition, but the sample size for each partition becomes small reducing prediction accuracy

Engineering Contradiction:
Improveability to handle different missing value patternsVSAvoidprediction accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent merges samples with similar missing value patterns into the same cluster, creating larger aggregated groups rather than treating each unique pattern separately. This merging increases the sample size for each cluster, enabling machine learning to achieve sufficient statistical power and prediction accuracy while still maintaining the ability to handle different missing value patterns through the clustering structure

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS10510005B2Prediction function creation device, prediction function creation method, and computer-readable storage medium
Publication Date: 2019.12.17 NEC CORP
  • US10510005B2 patent drawing
  • US10510005B2 patent drawing
  • US10510005B2 patent drawing

AI summary

The prediction function creation device according to the present invention for creating a prediction function to derive an objective variable by using a set of samples that include explanatory variables and an objective variable, the device includes: a clustering unit that clusters the respective samples by giving labels, and assigns weights to each label in accordance with patterns of missing values for the explanatory variables in labeled samples; a child model creation unit that makes portions of the training data partial training data on the basis of the weights, and determines an explanatory variable that constitutes the prediction function on the basis of patterns of missing values for the explanatory variables in the samples; and a mixture model creation unit that creates the prediction function with respect to each pattern of missing values by using the explanatory variable and the determined partial training data.