Neural Unlikelihood Training for Diverse Keyphrase Generation

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Solution Overview

Problem

Existing keyphrase generation systems face challenges in producing diverse and non-repetitive keyphrases, often requiring extensive computational resources and post-processing to remove duplicates, which can impact the quality and efficiency of downstream computing systems.

Innovation Solution

The proposed system employs a sequence-to-sequence machine learning model with an unlikelihood training objective that penalizes the decoder for generating repetitive tokens, using a combination of target and copy unlikelihood losses, and incorporates K-step ahead token prediction to enhance diversity and reduce the need for post-processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If exhaustive beam search decoding is used to generate a large number of keyphrases, then the diversity of keyphrases is improved, but the computational resources required increase significantly

Engineering Contradiction:
Improvediversity of keyphrasesVSAvoidcomputational resources
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by performing unlikelihood training during the model training phase to preemptively reduce repetition. The model is trained with a loss function that penalizes repetitive token generation, so that when inference occurs, the model inherently produces diverse keyphrases without requiring exhaustive beam search or post-processing deduplication. This shifts the diversity-enhancing action to the training stage rather than the inference stage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of repetition into a benefit by using unlikelihood training. The loss function specifically targets repetitive tokens and penalizes them, turning the problem of repetition into a learning signal that guides the model to generate diverse keyphrases. The harmful redundancy is transformed into a constructive training objective that improves diversity while reducing computational waste.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Loss of substance

If post-processing is applied to remove duplicate keyphrases, then the redundancy is reduced, but the processing time and computational overhead increase

Engineering Contradiction:
Improveredundancy of keyphrasesVSAvoidprocessing time
Core Design Contradiction:
Loss of substanceVSLoss of time

Solution Approach 1:

The patent performs the deduplication action preliminarily during training through unlikelihood training. The model learns to avoid generating repetitive keyphrases by being penalized for doing so during training. This preliminary learning eliminates the need for post-processing deduplication, as the model produces diverse keyphrases directly during inference, saving significant processing time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The model performs self-service by inherently generating diverse keyphrases without requiring external post-processing intervention. Through unlikelihood training, the model develops an internal mechanism to avoid repetition, making it self-sufficient in producing high-quality diverse keyphrases without needing additional processing steps to remove duplicates.

Inventive Principle:
Principle #25Self-service

3Productivity

If rule-based approaches are used for keyphrase extraction, then the process is simple and fast, but the output quality and diversity are poor

Engineering Contradiction:
Improveextraction speedVSAvoiddiversity of keyphrases
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical rule-based systems with a neural network-based sequence-to-sequence model trained with unlikelihood training. This substitution transitions from rigid, pre-programmed rules to a learned, adaptive system that can generate diverse and context-appropriate keyphrases. The neural model captures complex patterns in the data that rule-based systems cannot, improving both diversity and quality while maintaining computational efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of how keyphrases are generated - from fixed rule-based selection to probabilistic neural generation with unlikelihood training. By modifying the generation mechanism to use a trained model with a specialized loss function that penalizes repetition, the system achieves high diversity without sacrificing extraction speed, as the model generates keyphrases directly during inference.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If the model is trained to generate accurate keyphrases, then the output quality is improved, but the diversity decreases due to repetition

Engineering Contradiction:
Improveaccuracy of keyphrasesVSAvoiddiversity of keyphrases
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies anti-weight by introducing a counterbalancing force against repetition through the unlikelihood training loss function. While standard training objectives push the model toward accurate predictions (which can lead to repetition), the unlikelihood loss acts as a counterweight that penalizes repetitive tokens. This creates a balanced optimization process where the model learns to generate both accurate and diverse keyphrases simultaneously.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent introduces dynamics by making the training objective adaptive and multi-faceted. Instead of a static single objective, the model is trained with a dynamic loss function that combines accuracy-oriented terms with diversity-oriented unlikelihood penalties. This dynamic training approach allows the model to adaptively balance between generating accurate keyphrases and maintaining diversity, adjusting its predictions based on both quality and repetition considerations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11893348B2Training a machine learning system for keyword prediction with neural likelihood
Publication Date: 2024.02.06 ROYAL BANK OF CANADA
  • US11893348B2 patent drawing
  • US11893348B2 patent drawing
  • US11893348B2 patent drawing

AI summary

Computer implemented methods and systems are provided for generating diverse key phrases while maintaining competitive output quality. A system for training a sequence to sequence (S2S) machine learning model is proposed where neural unlikelihood objective approaches are used at (1) a target token level to discourage the generation of repeating tokens, and (2) a copy token level to avoid copying repetitive tokens from the source text. K-step ahead token prediction approaches are also proposed as an additional mechanism to augment the approach to further enhance the overall diversity of key phrase outputs.