Cascaded Machine Learning Models for Recommendation List Optimization

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Solution Overview

Problem

Recommender systems face limitations in providing personalized recommendations due to incomplete information and uncertainty, leading to user dissatisfaction and suboptimal interactions, as they rely on individual item scores and rankings without considering the overall list context.

Innovation Solution

A two-level cascaded machine learning approach is employed, where a first-level model generates predictions for individual items and a second-level model evaluates these predictions to optimize the list of recommendations, with iterative swapping strategies to enhance user interaction probabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a recommender system presents top-ranked items based on individual item scores, then the system can provide personalized recommendations efficiently, but the recommendations may not reflect the user's true interests due to incomplete information and uncertainty

Engineering Contradiction:
Improverecommendation generation efficiencyVSAvoidrecommendation quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces an intermediary list-level model that acts as a mediator between individual item predictions and final recommendations. This intermediary layer aggregates item-level features and applies list-level constraints to produce more reliable recommendations that reflect both individual item quality and overall list coherence, resolving the contradiction between efficient generation and reliable output.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from a single-dimension approach (individual item scoring) to a multi-dimensional approach by adding list-level features and constraints. This dimensional expansion allows the system to consider both item-quality dimensions and list-coherence dimensions, thereby improving recommendation reliability while maintaining efficiency through the structured two-level modeling framework.

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

2Ease of operation

If the recommender system uses incomplete user profile information, then the system can operate with available data, but the predictive power is imperfect and may not capture user preferences accurately

Engineering Contradiction:
Improvesystem operability with available dataVSAvoiduser preference prediction accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where list-level model predictions are fed back into the recommendation generation process. The list-level model provides corrective feedback that adjusts item-level predictions based on overall list context, thereby improving measurement precision of user preferences while maintaining ease of operation by working within the constraints of available data.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary feature aggregation and list-level constraint application before final recommendation generation. By pre-computing list-level features and applying constraints in advance, the system prepares enhanced prediction capabilities without adding operational complexity during real-time recommendation delivery, thus improving accuracy while maintaining ease of operation.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the recommender system presents items selected by substantially the same criteria, then the system can maintain consistency in recommendation approach, but all items in the list may fail to interest the user if the criteria are flawed

Engineering Contradiction:
Improverecommendation criteria consistencyVSAvoiduser interaction probability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent segments the recommendation system into two distinct levels: item-level modeling and list-level modeling. This segmentation allows different criteria to be applied at each level - item-level criteria for individual quality assessment and list-level criteria for overall coherence and diversity. This resolves the contradiction by maintaining consistency within each level while introducing variability across levels to improve user interaction probability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic adjustment mechanisms where list-level constraints can modify item selections based on overall list characteristics. This dynamic approach allows the system to maintain stability in its core recommendation approach while adapting to list-level conditions, thereby improving reliability of user interactions without completely abandoning consistent criteria.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11538086B2Recommender systems and methods using cascaded machine learning models
Publication Date: 2022.12.27 AMADEUS SAS
  • US11538086B2 patent drawing
  • US11538086B2 patent drawing
  • US11538086B2 patent drawing

AI summary

Computer-implemented methods of providing personalized recommendations to a user of items available in an online system, and related systems. First-level features including context features are computed based upon context data. A first-level machine learning model is then evaluated using the first-level features to generate predictions of user behavior in relation to a plurality of individual items available via the online system. A list of proposed item recommendations is constructed based upon the predictions. Second-level features are computed based upon the context data and list features based upon the list of proposed item recommendations and the corresponding predictions generated by the first-level machine learning model. A second-level machine learning model is evaluated using the second-level features to generate a prediction of user behavior in relation to the list of proposed item recommendations. A personalized list of item recommendations is provided based upon the prediction generated by the second-level machine learning model.