Prediction Rule Calibration for Interpretability and Accuracy

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Solution Overview

Problem

Existing prediction rules in learning models, such as those determining whether a medical device is defective or non-defective using sensor data, are often unclear and lack alignment with expert knowledge, leading to unreliability even when highly accurate.

Innovation Solution

A prediction rule calibration system that includes a simplification unit, a branch condition search unit, and a threshold optimization unit, which use evaluation metrics and calibration information to modify and refine the prediction rules to ensure they are accurate, simple, and aligned with expert knowledge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the prediction rule is simplified to make it clear and understandable, then the interpretability is improved, but the accuracy may deteriorate

Engineering Contradiction:
ImproveinterpretabilityVSAvoidaccuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The system changes parameters of the prediction rule including branch conditions, thresholds, and prediction values to transform a complex accurate model into a simplified interpretable model that maintains acceptable accuracy. The parameter change process involves modifying the prediction rule iteratively while evaluating accuracy metrics to ensure the simplified rule remains reliable.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The prediction rule is segmented into distinct components including branch conditions, thresholds, and prediction values. This segmentation allows systematic modification of each component independently, enabling the transformation from complex to simple while maintaining the overall predictive function through controlled changes to individual segments.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the prediction rule is modified to match expert knowledge, then the reliability is improved, but the complexity increases

Engineering Contradiction:
ImprovereliabilityVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses accuracy evaluation metrics as feedback to guide the modification process. By continuously evaluating the accuracy of the prediction rule during parameter changes, the system ensures that modifications to match expert knowledge do not compromise the rule's reliability, creating a feedback-controlled optimization process.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The prediction rule is treated as a dynamic structure that can be iteratively modified. The system dynamically adjusts branch conditions, thresholds, and prediction values based on expert knowledge and accuracy evaluation, allowing the rule to evolve from an initial complex state to a refined state that balances expert alignment with simplicity.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the prediction rule is made simple using basic rules, then the ease of understanding is improved, but the accuracy deteriorates

Engineering Contradiction:
Improveease of understandingVSAvoidaccuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system systematically changes parameters of simple prediction rules including branch conditions, thresholds, and prediction values to improve accuracy while maintaining simplicity. This parameter optimization process transforms basic easy-to-understand rules into refined simple rules that achieve both ease of understanding and acceptable accuracy through iterative parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20220156602A1Prediction rule calibration system and prediction rule calibration method
Publication Date: 2022.05.19 HITACHI LTD
  • US20220156602A1 patent drawing
  • US20220156602A1 patent drawing
  • US20220156602A1 patent drawing

AI summary

In classification problems or regression problems, a prediction rule that is highly accurate, simple, and in match with the knowledge of experts is obtained. A system includes a prediction rule simplification unit that simplifies a prediction rule of a learning model using an evaluation metric and a restriction; a branch condition search unit that updates a part of the simplified branch condition for prediction rule based on calibration information expressing a request for a prediction value or a specific branch condition; and a threshold optimization unit that updates a part of a threshold of the simplified prediction rule based on the calibration information.