Discretizing Numerical Variables for Cause-Effect Estimation

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Solution Overview

Problem

Existing methods struggle to estimate cause-effect relationships between multiple variables, particularly when categorical and numerical variables are mixed, as they face difficulties in assigning labels and determining whether to discretize numerical variables based on categorical variables, leading to challenges in building models like partial ancestral graphs.

Innovation Solution

An information processing apparatus and method that discretizes numerical variables based on categorical variables within a graphical model, using a discretization section to create discrete variables for conditional independence testing, allowing for the estimation of cause-effect relationships even when categorical and numerical variables are mixed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conditional independence testing is performed with mixed categorical and numerical variables, then cause-effect relationship estimation becomes possible, but difficulty in assigning labels and determining discretization arises

Engineering Contradiction:
Improvecause-effect relationship estimation accuracyVSAvoidmodel building complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the variable processing by distinguishing between categorical variables and numerical variables. Numerical variables are discretized into categorical forms based on categorical variables, allowing the system to handle mixed variable types through separate processing paths that ultimately integrate in the graphical model construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter state of numerical variables by transforming them from continuous values to discrete categorical values through discretization. This parameter transformation enables the application of conditional independence testing methods designed for categorical variables to mixed variable sets, resolving the complexity of handling different variable types simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If numerical variables are discretized based on categorical variables, then conditional independence testing becomes feasible, but additional processing steps are required

Engineering Contradiction:
Improvevariable type compatibilityVSAvoidprocessing procedure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary discretization of numerical variables based on categorical variables before conducting conditional independence testing. This preliminary action prepares the data in a uniform format that facilitates subsequent testing and model construction, eliminating the need to handle different variable types during the main processing phase.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces discretization as an intermediary process that converts numerical variables into categorical variables. This intermediary transformation enables the direct application of categorical variable testing methods to mixed variable sets, serving as a bridge between different variable type processing requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If discrete variables are used for testing, then conditional independence can be tested effectively, but information loss during discretization may occur

Engineering Contradiction:
Improveindependence test reliabilityVSAvoidnumerical variable information loss
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies local quality by performing discretization selectively based on the specific requirements of conditional independence testing. Rather than uniformly discretizing all numerical variables, the method discretizes only when and where categorical variables serve as conditioning variables, preserving numerical precision where it maintains test reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies partial discretization rather than complete discretization of all numerical variables. By discretizing only the portions of numerical variables that require categorical form for specific testing scenarios, the method achieves sufficient test reliability while minimizing information loss in the overall dataset.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS9852378B2Information processing apparatus and information processing method to estimate cause-effect relationship between variables
Publication Date: 2017.12.26 SONY GROUP CORP
  • US9852378B2 patent drawing
  • US9852378B2 patent drawing
  • US9852378B2 patent drawing

AI summary

Provided is an information processing apparatus that tests independence between multiple variables, the information processing apparatus including: a discretization section that discretizes at least one numerical variable on the basis of at least one categorical variable, when the categorical variable and the numerical variable are included in at least two dependent variables in a graphical model and a set of conditional variables serving as conditions of independence between the two variables; and a test execution section that executes a test for conditional independence between the two variables by using the categorical variable and a discrete variable which is obtained by discretizing the numerical variable.