Prototypical Option Discovery for Interpretable Imitation Learning

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Solution Overview

Problem

Existing imitation learning models lack transparency, limiting their application in decision-making scenarios due to their 'black-box' nature, especially in fields like healthcare and finance, where interpretability is crucial.

Innovation Solution

The introduction of prototypical option discovery (IPOD) framework for interpretable imitation learning, which segments expert trajectories into prototypical options using LSTM with soft-attention, learns segment embeddings, and constructs interpretable policies by comparing states to prototypical option embeddings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If imitation learning models are used to achieve automated decision-making, then productivity and automation extent are improved, but interpretability and transparency deteriorate due to black-box nature

Engineering Contradiction:
Improveautomated decision-makingVSAvoidinterpretability
Core Design Contradiction:
Extent of automationVSLoss of information

Solution Approach 1:

The patent segments the expert trajectory into multiple discrete options or skills, each representing a distinct sub-task or action sequence. This segmentation allows the system to break down complex decision-making into interpretable components while maintaining automation, directly resolving the contradiction between automation extent and interpretability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If complex imitation learning models are used to capture expert behavior, then reliability and accuracy are improved, but device complexity increases

Engineering Contradiction:
Improveexpert behavior captureVSAvoidmodel complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs dynamic option discovery that adapts to the specific task and expert behavior being learned. The system dynamically identifies and segments relevant skills based on the trajectory data, rather than using a fixed complex model structure. This dynamic approach maintains reliability in capturing expert behavior while managing model complexity through adaptive simplification.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If detailed trajectory analysis is performed to understand expert policy, then measurement precision is improved, but loss of time increases due to computational complexity

Engineering Contradiction:
Improveexpert policy understandingVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts essential features and skills from expert trajectories by identifying discrete options and their corresponding state segments. This extraction process captures the critical elements of expert policy understanding while discarding redundant information, thereby achieving measurement precision without proportional increases in computational time.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS20250299111A1Interpretable imitation learning via prototypical option discovery for decision making
Publication Date: 2025.09.25 NEC LABORATORIES AMERICA INC
  • US20250299111A1 patent drawing
  • US20250299111A1 patent drawing
  • US20250299111A1 patent drawing

AI summary

A method for learning prototypical options for interpretable imitation learning is presented. The method includes initializing options by bottleneck state discovery, each of the options presented by an instance of trajectories generated by experts, applying segmentation embedding learning to extract features to represent current states in segmentations by dividing the trajectories into a set of segmentations, learning prototypical options for each segment of the set of segmentations to mimic expert policies by minimizing loss of a policy and projecting prototypes to the current states, training option policy with imitation learning techniques to learn a conditional policy, generating interpretable policies by comparing the current states in the segmentations to one or more prototypical option embeddings, and taking an action based on the interpretable policies generated.