Query Auto-Completion Ranking via Earth Mover's Distance

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Solution Overview

Problem

Existing query auto-completion systems in eCommerce do not effectively account for dynamic changes in product information supply and demand in consumer-to-consumer online marketplaces, leading to inefficient product retrieval.

Innovation Solution

The method employs Earth Mover's Distance (EMD) matching to evaluate search terms based on costs and frequencies, constructing a cost matrix and optimizing term vectors to rank queries for product retrieval efficiency, considering both query-side demand and product-side supply constraints, thereby suggesting the most efficient search terms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional query auto-completion methods (MPK or basic learning-based approaches) are used, then implementation simplicity is maintained, but product retrieval efficiency deteriorates due to ignoring dynamic product information supply changes

Engineering Contradiction:
Improveproduct retrieval efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic query auto-completion by continuously updating the supply-demand difference based on real-time product information changes. The system dynamically adjusts the QAC ranking by incorporating the time-varying supply-demand difference, making the previously static MPK approach adaptive to changing marketplace conditions. This resolves the contradiction by making the system dynamic without requiring complete redesign.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces a feedback mechanism where the supply-demand difference is calculated based on product information changes and fed back into the query auto-completion ranking. This feedback loop allows the system to adjust recommendations based on actual marketplace dynamics, improving retrieval efficiency while maintaining a relatively simple architecture by reusing existing components with an added feedback layer.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If query auto-completion considers only query-side features (time, location, behavior), then implementation complexity is reduced, but retrieval accuracy deteriorates due to ignoring product supply dynamics

Engineering Contradiction:
Improvequery evaluation accuracyVSAvoidfeature engineering complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges query-side demand features with product-side supply features by calculating the supply-demand difference. Instead of treating them separately, the system combines both aspects into a unified metric that reflects the actual marketplace state. This merging improves evaluation accuracy by considering both perspectives without requiring entirely separate processing pipelines.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the feature engineering into distinct components: query-side features (time, location, behavior) and product-side features (supply changes, product information updates). By segmenting the problem, the system can process each type of feature independently and then combine them through the supply-demand difference calculation, making the overall system more manageable and interpretable.

Inventive Principle:
Principle #1Segmentation

3Reliability

If static product information assumptions are made, then processing speed is improved, but retrieval relevance deteriorates in C2C marketplaces where product information changes frequently

Engineering Contradiction:
Improveretrieval relevanceVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies partial action by not requiring complete re-processing of all product information changes. Instead, it tracks and processes only the relevant supply-side changes that affect query auto-completion rankings. This selective approach maintains retrieval relevance by responding to important changes while avoiding the overhead of processing every possible update, thus preserving processing speed.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11341175B2Keyword ranking for query auto-completion based on product supply and demand
Publication Date: 2022.05.24 MERCARI INC(JP)
  • US11341175B2 patent drawing
  • US11341175B2 patent drawing
  • US11341175B2 patent drawing

AI summary

For query auto completion (QAC) in an eCommerce platform with constantly changing product supply and demand, a Query Mover's Distance (QMD) framework for ranking queries is used, which formulates QAC as an optimal transport problem balancing product demand and supply.