Neighbor-Score Matrix for Binary Collaborative Filtering

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Solution Overview

Problem

Collaborative filtering systems face challenges in generating accurate recommendations using binary implicit feedback data, as latent factor approaches perform poorly on such data due to increased signal noise and difficulty in gauging preference degrees.

Innovation Solution

The method involves converting binary data into a neighbor-score matrix using a neighborhood-based approach and applying singular value decomposition (SVD) for factorization, allowing for the derivation of accurate user and item latent factors, which are then used to compute scores for recommendations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If latent factor approaches are used for collaborative filtering, then real-time recommendations can be generated, but performance deteriorates when using binary implicit feedback data due to signal noise and inability to gauge preference degrees

Engineering Contradiction:
Improvereal-time recommendation generationVSAvoidpreference measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent transforms binary preference data (0 or 1) into continuous score values by computing the number of common neighbors between user-item pairs. This parameter transformation converts discrete binary data into continuous measurements that reflect preference strength, enabling latent factor models to process implicit feedback data effectively while maintaining real-time recommendation capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a neighbor-score matrix as an intermediary representation between the original binary feedback matrix and the latent factor decomposition. This intermediary matrix captures the strength of preferences through neighbor overlap scores, bridging the gap between binary data and continuous latent factor requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If binary implicit feedback data is used, then data collection cost is reduced and quantity is increased, but recommendation accuracy deteriorates due to signal noise and loss of preference degree information

Engineering Contradiction:
Improvedata collection efficiencyVSAvoidpreference measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies parameter transformation by converting binary indicators into continuous scores based on neighbor overlap. This allows the system to retain the ease of binary data collection while recovering preference degree information through the computed scores, thereby improving measurement precision without sacrificing data collection efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary transformation of binary data into neighbor-score matrices before applying latent factor decomposition. This preliminary action enriches the binary data with preference strength information in advance, enabling more accurate recommendations while maintaining the original data collection advantages

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10932003B2Method and system for making recommendations from binary data using neighbor-score matrix and latent factors
Publication Date: 2021.02.23 THE TORONTO DOMINION BANK
  • US10932003B2 patent drawing
  • US10932003B2 patent drawing
  • US10932003B2 patent drawing

AI summary

One embodiment is a method executed by a computer system that applies collaborative filtering to provide a recommendation to a user. The method includes retrieving a binary matrix that includes rows and columns of binary data for preferences of users on items; applying a neighborhood-based approach to convert the binary matrix into a neighbor-score matrix; applying a factorization to approximate the neighbor-score matrix with a product of lower rank matrices; calculating a user factor and an item factor based on the factorization; calculating scores for user-item pairs by computing a dot product between the user factor and the item factor; sorting the scores of the user-item pairs to generate the recommendation to the user; and providing the recommendation to a general-purpose computer of the user.