Link Prediction with Positive-Unlabeled Learning for Incomplete Graphs

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Solution Overview

Problem

Conventional link prediction technologies for edge-incomplete graphs fail to consider unobserved missing edges, leading to overfitting and inability to propagate information between unconnected nodes, thus requiring a method that accurately predicts potential connections by processing observed edges as positive data and unconnected node pairs as unlabeled data.

Innovation Solution

A link prediction model is trained using positive-unlabeled data learning, converting edge-incomplete graphs into expected graphs with random variables, and applying dual and correction loss functions to balance edge connections, preventing overfitting and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional link prediction techniques presume edges are fully-observed and do not consider unobserved missing edges, then the model can be trained on given graph edges, but it becomes impossible to propagate information between unconnected nodes, leading to overfitting

Engineering Contradiction:
Improvelink prediction accuracyVSAvoidability to handle unconnected nodes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by constructing an expected graph that includes both observed edges and unobserved missing edges before training the link prediction model. This expected graph is built using domain knowledge and heuristics to predict potential connections that should exist but are currently unobserved. By preparing this augmented graph structure in advance, the model can learn from both connected and unconnected node pairs, preventing overfitting and improving generalization to real-world scenarios where edges may be missing.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the model processes only observed edges as positive data, then training is simplified, but unconnected node pairs cannot be utilized for information propagation

Engineering Contradiction:
Improvetraining efficiencyVSAvoidinformation between unconnected nodes
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent applies segmentation by dividing the training data into three distinct segments: observed edges (positive samples), unobserved missing edges (negative samples), and unconnected node pairs (unlabeled samples). Each segment is processed differently during training - observed edges provide confirmed connection patterns, unobserved edges provide counter-examples of non-connections, and unconnected pairs provide additional unlabeled data for self-supervised learning. This segmented approach allows the model to efficiently utilize all available information while maintaining training productivity through specialized processing for each data type.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If conventional techniques rely strongly on a given edge-incomplete graph, then the model can be trained on available data, but it cannot accurately predict potential future connections in edge-incomplete graphs

Engineering Contradiction:
Improvemodel training simplicityVSAvoidedge connection prediction accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces an expected graph as an intermediary structure that bridges the gap between the given edge-incomplete graph and the target prediction task. This expected graph incorporates domain knowledge, heuristics, and preliminary predictions to augment the original graph with potential missing edges. The link prediction model is then trained on this enriched expected graph rather than directly on the incomplete original graph, allowing it to learn more accurate connection patterns while maintaining training feasibility. The intermediary expected graph acts as a mediator that transforms the incomplete input into a more informative training representation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4592871A1Link prediction method and apparatus using accurate link prediction model based on positive-unlabeled data learning
Publication Date: 2025.07.30 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION
  • EP4592871A1 patent drawingFigure 1
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AI summary

Proposed herein are a link prediction method and apparatus. The link prediction method that is performed by the link prediction apparatus includes predicting one or more edges having a probability of being connected in the structure of an edge-incomplete graph by entering the edge-incomplete graph into a link prediction model. The link prediction model is a model that performs binary classification by processing at least one edge observed in the structure of the edge-incomplete graph as positive data and processing at least one node pair unconnected in the structure of the edge-incomplete graph as unlabeled data.