Cascading Category Recommender for Precise User-Specific Category Prediction

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Solution Overview

Problem

Existing recommender systems face challenges in category-level recommendations, including conflicting inferred categories, lossy user preferences, and the difficulty in maintaining high precision with a concise set of category recommendations, especially for users with limited interaction history.

Innovation Solution

A cascading category recommender system comprising a candidate category model, a per-user category encoder, and a category prediction model, which uses item-level dependent category embeddings and a precise-centric loss function to generate strong negative samples and user-specific category embeddings, optimizing for high precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional recommendation systems are used for category-level recommendations, then user engagement can be expanded to different types of items, but the precision of category recommendations deteriorates due to conflicting inferred categories and lossy user preferences

Engineering Contradiction:
Improveuser engagement expansionVSAvoidcategory recommendation precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The recommendation system is segmented into multiple specialized models: a candidate category model that generates potential categories, a per-user category encoder that creates user-specific embeddings, and a category prediction model that selects final recommendations. This segmentation allows each component to specialize in specific tasks, improving overall precision while maintaining versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The per-user category encoder generates category embeddings that are specific to each user's preferences and interaction patterns. This local quality approach ensures that category representations are tailored to individual users rather than using generic category embeddings, thereby improving recommendation precision for each user while maintaining system-wide adaptability.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If a concise set of category recommendations is provided, then ease of operation is improved, but the quantity of useful information is reduced leading to lossy user preferences

Engineering Contradiction:
Improverecommendation simplicityVSAvoiduser preference information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The system transitions from flat category lists to multi-dimensional category embeddings that capture user-specific preferences, item-level information, and category relationships. This dimensional enrichment allows the system to preserve rich user preference information while presenting a concise recommendation set, as the embeddings encode multiple aspects of user preferences in a compact form.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The candidate category model generates a broader set of potential categories beforehand, which are then filtered and refined by the category prediction model to produce the final concise recommendation set. This preliminary action ensures that comprehensive user preference information is considered before selecting the final concise recommendations, preventing information loss.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If item-level recommendations are used, then manufacturing precision of recommendations is improved, but device complexity increases making it challenging for users with little-known information

Engineering Contradiction:
Improverecommendation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Category-level recommendations serve as an intermediary layer between user interactions and item-level recommendations. The category embeddings capture item-level information in a simplified form that is easier to process, especially for cold-start users with limited interaction history. This intermediary approach maintains recommendation accuracy while reducing system complexity compared to direct item-level recommendations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The category embeddings serve multiple functions simultaneously: they represent user preferences, encode item characteristics, and facilitate both category-level and item-level recommendations. This multi-functionality reduces overall system complexity by using a single representation mechanism for multiple purposes, rather than requiring separate mechanisms for each function.

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

4Device complexity

If negative samples are not generated, then device complexity is reduced, but measurement precision of category recommendations deteriorates due to inability to distinguish positive from negative categories

Engineering Contradiction:
Improvemodel training complexityVSAvoidcategory discrimination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The candidate category model generates negative samples automatically from the category set without requiring external manual annotation or complex sampling mechanisms. This self-service approach to negative sample generation maintains measurement precision by providing sufficient positive-negative category pairs for training, while keeping the system complexity low through automated generation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS20250356411A1Cascading category recommender
Publication Date: 2025.11.20 EBAY INC
  • US20250356411A1 patent drawing
  • US20250356411A1 patent drawing
  • US20250356411A1 patent drawing

AI summary

Some aspects relate to technologies for category recommendation for a listing platform using a cascading category recommender. The cascading category recommender includes a candidate category model, a per-user category encoder, and a category prediction model. Given a sequence of interacted categories for a user, the candidate category model selects candidate categories from a category set that sets forth categories for item listings on a listing platform. The per-user category encoder generates a category embedding for each interacted category based on interacted items for the user corresponding to each interacted category. The category prediction model selects categories for recommendation using the candidate categories, the sequence of interacted categories, and the category embeddings.