Out-of-Domain Detection for Chatbot Utterances

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Solution Overview

Problem

Existing chatbot systems face challenges in identifying out-of-domain (OOD) utterances, which are not within the domain of intents the chatbot is trained to handle, leading to potential misinterpretation and poor user experience.

Innovation Solution

The implementation of an OOD detector within the chatbot system using a combination of clustering and metrics-based algorithms. This involves generating sentence embeddings for utterances, obtaining embedding representations for in-domain clusters, and using metric learning and outlier detection models to predict the probability of an utterance belonging to the target domain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional chatbot systems are used without OOD detection, then the system structure remains simple, but the reliability deteriorates due to misinterpretation of out-of-domain utterances

Engineering Contradiction:
Improveaccuracy of utterance classificationVSAvoidsystem architecture complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the utterance processing task into distinct components: an OOD detector module that first determines whether an utterance is out-of-domain, and a separate intent classification module that processes in-domain utterances. This segmentation allows the system to handle OOD utterances reliably without compromising the overall system structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The OOD detector serves as an intermediary component between the user input and the intent classification system. It acts as a gatekeeper that filters out OOD utterances before they reach the intent classification module, preventing misinterpretation while maintaining a clear separation of concerns in the system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If clustering and metric learning models are implemented for OOD detection, then the measurement precision improves for identifying OOD utterances, but the device complexity increases due to multiple model components

Engineering Contradiction:
Improveprecision of OOD utterance identificationVSAvoidnumber of model components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system merges clustering-based OOD detection with metric learning-based intent classification into a unified framework. The same embedding space is used for both clustering in-domain utterances and measuring distance to detect OOD utterances, eliminating the need for separate feature extraction pipelines and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The embedding model serves multiple functions: it generates representations for clustering in-domain utterances, computes distances for OOD detection, and provides features for intent classification. This multi-functionality reduces the number of separate components needed while maintaining high precision in OOD utterance identification.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If sentence embeddings and multiple models are used for OOD detection, then the reliability improves, but the computational resources and time increase

Engineering Contradiction:
Improveaccuracy of domain classificationVSAvoidprocessing time per utterance
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary clustering of in-domain utterances during the training phase, creating a static cluster structure that can be efficiently queried during inference. This preliminary action eliminates the need for complex real-time computations when processing user utterances, as the cluster assignments and centroids are pre-computed and stored.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the OOD detection threshold based on the distribution of distances between utterances and cluster centroids. By adapting the threshold to the specific characteristics of the data, the system maintains high reliability while avoiding overly conservative detection that would increase false positives and processing time.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS12299402B2Techniques for out-of-domain (OOD) detection
Publication Date: 2025.05.13 ORACLE INT CORP
  • US12299402B2 patent drawing
  • US12299402B2 patent drawing
  • US12299402B2 patent drawing

AI summary

The present disclosure relates to techniques for identifying out-of-domain utterances. One particular technique includes receiving an utterance and a target domain of a chatbot, generating a sentence embedding for the utterance, obtaining an embedding representation for each cluster of in-domain utterances associated with the target domain, predicting, using a metric learning model, a first probability that the utterance belongs to the target domain based on a similarity or difference between the sentence embedding and each embedding representation for each cluster, predicting, using an outlier detection model, a second probability that the utterance belongs to the target domain based on a determined distance or density deviation between the sentence embedding and embedding representations for neighboring clusters, evaluating the first probability and the second probability to determine a final probability, and classifying the utterance as in-domain or out-of-domain for the chatbot based on the final probability.