Prototypical Option Discovery for Transparent Imitation Policies

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Solution Overview

Problem

Existing imitation learning models lack transparency, limiting their application in decision-making scenarios like healthcare and finance, as they are considered 'black-boxes' and do not effectively explain their reasoning process.

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 prototypical contextual policies, and employs diversity regularization to ensure interpretability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If imitation learning models are used to mimic expert behaviors, then learning effectiveness is improved, but transparency and interpretability deteriorate making them 'black-boxes'

Engineering Contradiction:
Improvelearning effectivenessVSAvoidtransparency
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments expert trajectories into multiple discrete options or skills, where each option represents a meaningful sub-task or action sequence. This segmentation transforms the opaque imitation learning process into interpretable components that can be individually analyzed and understood, resolving the contradiction between learning effectiveness and transparency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces option embeddings as intermediary representations that bridge the gap between expert demonstrations and policy decisions. These embeddings serve as interpretable mediators that capture the essence of expert behaviors while maintaining transparency, allowing the system to maintain both learning effectiveness and interpretability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If complex policies are used to handle diverse decision-making scenarios, then adaptability is improved, but interpretability deteriorates

Engineering Contradiction:
Improvedecision-making capabilityVSAvoidinterpretability
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides complex decision-making policies into segmented options, where each option corresponds to a specific skill or action type. This segmentation enables the system to maintain adaptability across diverse scenarios while preserving interpretability, as each segmented option can be independently understood and explained.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning specific properties and meanings to different segments of the policy. Each option embedding captures local characteristics of expert behaviors in specific contexts, allowing the overall policy to be both versatile and interpretable through its locally-defined, meaningful components.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20250299112A1Interpretable imitation learning via prototypical option discovery for decision making
Publication Date: 2025.09.25 NEC LABORATORIES AMERICA INC
  • US20250299112A1 patent drawing
  • US20250299112A1 patent drawing
  • US20250299112A1 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.