Symmetric Graph Contrastive Learning against Noisy Views for Recommendation

TL;DR

Introduces SGCL method to improve recommendation accuracy by combating noisy views, achieving a 12.25% improvement.

cs.LG 🔴 Advanced 2024-08-03 6 views
Chu Zhao Enneng Yang Yuliang Liang Jianzhe Zhao Guibing Guo Xingwei Wang
contrastive learning recommender systems data augmentation graph neural networks noisy views

Key Findings

Methodology

This paper proposes a novel contrastive learning method called Symmetric Graph Contrastive Learning (SGCL) to enhance recommendation system performance. SGCL introduces symmetry theory to design a symmetric form and contrast loss resistant to noisy interference. This method effectively improves recommendation accuracy without relying on specific models. The core of SGCL is to enhance model tolerance to noisy views through a symmetric loss function.

Key Results

  • Experiments on three real-world datasets show that the SGCL method achieves up to 12.25% relative improvement in recommendation accuracy compared to nine competing models.
  • The experiments demonstrate a significant drop in recommendation performance when critical edges are removed, validating the negative impact of noisy views.
  • Ablation studies prove SGCL's robustness in handling noisy data, outperforming existing methods.

Significance

This study significantly improves recommendation system performance in noisy environments by proposing the SGCL method, addressing the performance degradation caused by noisy views in existing data augmentation methods. SGCL's theoretical guarantees and experimental validation provide new research directions for academia and practical solutions for industry recommendation systems.

Technical Contribution

SGCL introduces symmetry theory into contrastive learning, proposing a new symmetric loss function that maintains high recommendation accuracy in noisy environments. Compared to existing methods, SGCL is model-agnostic, offering broader applicability and stronger robustness.

Novelty

SGCL is the first method to introduce symmetry theory into contrastive learning, addressing the negative impact of noisy views on recommendation system performance. Compared to existing methods, SGCL provides theoretical noise tolerance guarantees.

Limitations

  • SGCL may still experience performance degradation when handling extremely noisy data.
  • The method's computational complexity is high, potentially affecting large-scale applications.

Future Work

Future research directions include optimizing SGCL's computational efficiency and exploring its potential applications in other fields. Further research on automatically identifying and handling noisy views is also important.

AI Executive Summary

In recommendation systems, existing graph contrastive learning methods generate contrastive views through data augmentation, but these methods may interfere with original connections, leading to performance degradation. This paper proposes a new method called Symmetric Graph Contrastive Learning (SGCL), which introduces symmetry theory to design a symmetric form and contrast loss resistant to noisy interference. Experimental results show that SGCL achieves up to 12.25% relative improvement in recommendation accuracy on three real-world datasets compared to nine competing models. SGCL's theoretical guarantees and experimental validation provide new research directions for academia and practical solutions for industry recommendation systems. Although SGCL performs well in handling noisy data, its computational complexity is high, and future research can further optimize its efficiency.

Deep Analysis

Background

In recent years, Graph Convolutional Networks (GCNs) have gained widespread attention in recommendation systems. GCNs effectively improve recommendation accuracy by learning complex user-item interaction representations. However, existing methods rely on high-quality labeled data, which is neither realistic nor economical in practical applications.

Core Problem

Existing graph contrastive learning methods generate contrastive views through data augmentation, but these methods may interfere with original connections, leading to generated views sharing less information with the original graph, forming noisy views, and affecting recommendation performance.

Innovation

SGCL introduces symmetry theory to design a symmetric form and contrast loss resistant to noisy interference. Unlike existing methods, SGCL is model-agnostic, offering broader applicability and stronger robustness.

Methodology

  • �� Introduce symmetry theory to design a symmetric loss function
  • �� Generate contrastive views through a contrastive learning framework
  • �� Enhance model tolerance to noisy views using a symmetric loss function
  • �� Conduct experiments on multiple datasets for validation

Experiments

Experiments are conducted on three real-world datasets, including Amazon-CD and Yelp2020. Baseline models used include SGL and KGCL. The main evaluation metric is recommendation accuracy (NDCG@20).

Results

SGCL achieves up to 12.25% relative improvement in recommendation accuracy compared to nine competing models. Experiments demonstrate a significant drop in performance when critical edges are removed, validating the negative impact of noisy views.

Applications

SGCL can be directly applied to recommendation systems that need to handle noisy data, especially when user behavior data is incomplete or inconsistent. Its theoretical guarantees and experimental validation provide practical solutions for industry recommendation systems.

Limitations & Outlook

SGCL may still experience performance degradation when handling extremely noisy data. The method's computational complexity is high, potentially affecting large-scale applications. Future research can further optimize its efficiency.

Plain Language Accessible to non-experts

Imagine a kitchen where a chef is preparing a grand meal. Each dish requires different ingredients and steps. Existing recommendation systems are like a chef, relying on high-quality ingredients (data) to create delicious dishes (recommendations). However, sometimes the ingredients may not be fresh (data noise), affecting the taste of the dish. SGCL is like an experienced chef who can ensure the dish's taste by adjusting cooking methods (symmetric loss function) even when the ingredients are not ideal.

ELI14 Explained like you're 14

Imagine you're playing a game where you need to find hidden treasure based on different clues. Existing recommendation systems are like a player relying on clear clues to find the treasure (recommendations). But sometimes the clues may not be clear (data noise), causing the player to lose direction. SGCL is like a smart player who can find the treasure by analyzing other information (symmetric loss function) even when the clues are unclear.

Glossary

Contrastive Learning

A method that learns data representations by contrasting different data views.

Used to enhance representation learning in recommendation systems.

Noisy Views

Views generated during data augmentation that share less information with the original data.

Negatively impact recommendation system performance.

Symmetric Loss

A noise-tolerant loss function that maintains model performance in noisy environments.

Used to enhance SGCL's robustness.

Graph Convolutional Network (GCN)

A neural network model for processing graph-structured data.

Used to model user-item interactions.

Data Augmentation

A method of generating new data samples by transforming existing data.

Used to generate contrastive views in contrastive learning.

Open Questions Unanswered questions from this research

  • 1 How to improve SGCL's efficiency without increasing computational complexity?
  • 2 How to automatically identify and handle noisy views to further improve recommendation performance?

Applications

Immediate Applications

Online Recommendation Systems

SGCL can be used to improve the performance of online recommendation systems in noisy data environments, especially when user behavior data is incomplete or inconsistent.

Long-term Vision

Cross-domain Recommendation

SGCL's theoretical guarantees and experimental validation provide new ideas for developing cross-domain recommendation systems, which can be applied to more complex scenarios in the future.

Abstract

Graph Contrastive Learning (GCL) leverages data augmentation techniques to produce contrasting views, enhancing the accuracy of recommendation systems through learning the consistency between contrastive views. However, existing augmentation methods, such as directly perturbing interaction graph (e.g., node/edge dropout), may interfere with the original connections and generate poor contrasting views, resulting in sub-optimal performance. In this paper, we define the views that share only a small amount of information with the original graph due to poor data augmentation as noisy views (i.e., the last 20% of the views with a cosine similarity value less than 0.1 to the original view). We demonstrate through detailed experiments that noisy views will significantly degrade recommendation performance. Further, we propose a model-agnostic Symmetric Graph Contrastive Learning (SGCL) method with theoretical guarantees to address this issue. Specifically, we introduce symmetry theory into graph contrastive learning, based on which we propose a symmetric form and contrast loss resistant to noisy interference. We provide theoretical proof that our proposed SGCL method has a high tolerance to noisy views. Further demonstration is given by conducting extensive experiments on three real-world datasets. The experimental results demonstrate that our approach substantially increases recommendation accuracy, with relative improvements reaching as high as 12.25% over nine other competing models. These results highlight the efficacy of our method.

cs.LG cs.AI cs.IR