Interpretable Policy Creation Using Rule-Based Reinforcement Learning

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Solution Overview

Problem

The reinforcement learning method used to express know-how in processing plants is difficult for users to understand due to its reliance on neural networks, making it challenging to transfer high-quality work procedures effectively.

Innovation Solution

A policy creation apparatus that generates policies with a combination of rules for determining object states and actions, including action determination, policy evaluation, and selection, allowing for high-quality and visible policy creation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If reinforcement learning method with neural network is used to express know-how, then policy quality is improved, but user understanding and visibility deteriorate

Engineering Contradiction:
Improvepolicy qualityVSAvoiduser understanding
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent segments the neural network policy into multiple interpretable rules, each representing a specific condition-action pair. This segmentation allows the system to maintain high policy quality through neural network learning while improving user understanding by presenting discrete, explainable rules instead of a monolithic black-box model.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary layer that translates neural network outputs into human-readable rules. This intermediary mechanism bridges the gap between the high-performance neural network representation and the user-friendly rule-based format, enabling both high policy quality and good user understanding.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If neural network model is used to represent policies, then learning capability is improved, but model interpretability deteriorates

Engineering Contradiction:
Improvelearning capabilityVSAvoidmodel interpretability
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent divides the neural network's decision-making process into segmented rules that can be individually interpreted. Each rule captures a specific aspect of the learned policy, preserving the learning capability of the neural network while recovering interpretability through structured rule representation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter representation from continuous neural network weights to discrete rule parameters with explicit conditions and actions. This parameter transformation maintains the expressive power needed for learning while making the model interpretable through human-understandable parameter meanings.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11841689B2Policy creation apparatus, control apparatus, policy creation method, and non-transitory computer readable medium storing policy creation program
Publication Date: 2023.12.12 NEC CORP
  • US11841689B2 patent drawing
  • US11841689B2 patent drawing
  • US11841689B2 patent drawing

AI summary

A policy creation unit creates a plurality of policies each including a predetermined number of rules in which a condition for determining a state of an object is combined with an action in the state. An action determination unit determines, for each of the plurality of created policies, an action to be performed while a state of the object is changed from a first state to a second state in accordance with the policy. A policy evaluation unit determines, in accordance with a difference between a state between the first state and the second state and a desired state, the quality of the determined action and determines, for each of the plurality of policies, the quality of the policy based on the determined quality of the action. A policy selection unit selects the policy that is determined to have a high quality.