Probabilistic State RNNs for Interpretable Sequence Classification

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Solution Overview

Problem

Existing recurrent neural networks (RNNs) face difficulties in understanding, debugging, and verifying their inner workings, and struggle to extrapolate to longer input sequences, making it challenging to inspect and deploy them effectively in applications like natural language processing and network management.

Innovation Solution

The introduction of state-regularized RNNs (SR-RNNs) with a probabilistic state transition mechanism allows for the extraction of deterministic finite automata (DFAs) directly from trained RNNs, enabling improved generalization and predictability by restricting the model to a finite number of states, which can be inspected and adjusted before deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional recurrent neural networks are used, then sequence classification capability is achieved, but the model becomes difficult to understand, debug, and verify

Engineering Contradiction:
Improvemodel interpretabilityVSAvoidnetwork structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and isolates the state component from the recurrent neural network, separating it into a distinct probabilistic state machine module. This extraction allows the state transitions to be made explicit and inspectable, while the rest of the network maintains its computational power for sequence processing. The state component can be independently analyzed, debugged, and verified without affecting the overall network functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The recurrent neural network is segmented into distinct functional components: the probabilistic state machine module that handles state transitions, and the remaining network components that handle sequence processing. This segmentation allows each component to be optimized and inspected independently, improving overall interpretability while maintaining the network's computational capabilities.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If traditional recurrent neural networks are used, then sequence processing is performed, but the model struggles to extrapolate to longer input sequences

Engineering Contradiction:
Improvesequence length generalizationVSAvoidprediction accuracy for long sequences
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a dynamic probabilistic state transition mechanism that adapts to different sequence lengths. The probabilistic nature of the state transitions allows the model to handle variable-length sequences effectively, while the finite state space ensures that the model can generalize to longer sequences that were not present in the training data. The state transitions are updated based on observed sequences, enabling continuous adaptation to new patterns.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The model utilizes parameter changes in the probabilistic state transition probabilities to adapt to different sequence lengths. By learning from training data, the state transition parameters are updated to reflect the underlying patterns in the data, enabling the model to generalize effectively to longer sequences. The probabilistic parameters allow for flexible adaptation to varying sequence characteristics.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If recurrent neural networks are trained on sequence data, then classification capability is improved, but the inner workings become opaque and difficult to inspect

Engineering Contradiction:
Improvesequence classification performanceVSAvoidinternal state observability
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The probabilistic state machine acts as an intermediary layer between the input sequences and the final classification output. This intermediary component makes the internal workings of the network observable and inspectable, as the state transitions can be tracked and analyzed. The state component serves as a mediator that translates complex sequence processing into a series of interpretable state changes, while still maintaining the network's classification performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS11694062B2Recurrent neural networks having a probabilistic state component and state machines extracted from the recurrent neural networks
Publication Date: 2023.07.04 NEC CORP
  • US11694062B2 patent drawing
  • US11694062B2 patent drawing
  • US11694062B2 patent drawing

AI summary

A computer-implemented method includes instantiating a neural network including a recurrent cell. The recurrent cell includes a probabilistic state component. The method further includes training the neural network with a sequence of data. In an embodiment, the method includes extracting a deterministic finite automaton from the trained recurrent neural network and classifying a sequence with the extracted automaton.