Non-autoregressive Dialog State Tracking via Fertility Decoding

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Solution Overview

Problem

Task-oriented dialog systems using neural networks face high time costs due to complex dialog contexts and multiple domains, particularly in dialog state tracking, which affects performance and latency in generating real-time responses.

Innovation Solution

The implementation of a non-autoregressive decoding framework for dialog state tracking, which learns inter-dependencies across slots and domains, allowing for joint state tracking and reducing inference latency by generating dialog states as structured sequences, using fertility to manage token copying and employing a two-stage decoding process with fertility and state decoders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If typical dialog state tracking approaches are used in task-oriented dialog systems, then the system can handle multiple dialog domains, but the inference latency increases significantly

Engineering Contradiction:
Improvemulti-domain handling capabilityVSAvoidinference latency
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the dialog state tracking process into two independent decoders: a fertility decoder that determines the number of tokens to copy from dialog history, and a state decoder that generates the actual dialog state. This segmentation allows parallel processing of different aspects of state tracking, reducing overall inference latency while maintaining multi-domain adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fertility decoder performs preliminary action by first determining the fertility values (number of tokens to copy) for each dialog history token before the state decoder generates the final dialog state. This preliminary determination of token copying strategy enables more efficient subsequent state generation and reduces total inference time.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If complex dialog contexts are processed to maintain accuracy across multiple domains, then the system achieves better task completion, but the processing time increases

Engineering Contradiction:
Improvedialog state tracking accuracyVSAvoidresponse generation speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent uses a copying mechanism where the fertility decoder determines how many tokens from the dialog history should be copied into the dialog state representation. This copying approach preserves important contextual information from the full dialog history without requiring complete reprocessing, thereby maintaining tracking accuracy while reducing computational burden and improving response speed.

Inventive Principle:
Principle #26Copying

3Reliability

If traditional sequential decoding is used for dialog state tracking, then the model can capture dependencies, but the inference time cost is high

Engineering Contradiction:
Improvedependency capture capabilityVSAvoidinference time cost
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent divides the sequential decoding process into two parallel decoder components that operate simultaneously. The fertility decoder and state decoder process different aspects of the dialog state tracking in parallel, reducing the overall sequential dependency chain length and inference time while still capturing necessary dependencies through their respective attention mechanisms.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11568000B2System and method for automatic task-oriented dialog system
Publication Date: 2023.01.31 SALESFORCE INC
  • US11568000B2 patent drawing
  • US11568000B2 patent drawing
  • US11568000B2 patent drawing

AI summary

A method for dialog state tracking includes decoding, by a fertility decoder, encoded dialog information associated with a dialog to generate fertilities for generating dialog states of the dialog. Each dialog state includes one or more domains. Each domain includes one or more slots. Each slot includes one or more slot tokens. The method further includes generating an input sequence to a state decoder based on the fertilities. A total number of each slot token in the input sequence is based on a corresponding fertility. The method further includes encoding, by a state encoder, the input sequence to the state decoder, and decoding, by the state decoder, the encoded input sequence to generate a complete sequence of the dialog states.