LI Pu-cong, WANG Si-zhe , FAN Jia-jun , CAI Xin-yi , XIONG Yong-tao
Accepted: 2026-09-18
To address the key challenges faced by existing graph neural network (GNN) based multi‑criteria recommendation algorithms under data‑sparse conditions—namely the long‑tail effect, the difficulty in synergistically integrating graph attention networks (GAT) and graph convolutional networks (GCN) , and the ambiguous discrimination between positive and negative samples caused by the difficulty of contrastive learning anchor selection in multi‑criteria rating scenarios—this paper proposes a multi‑criteria recommendation algorithm that fuses noisy graph neural networks with contrastive learning, termed NGCLR. The research objective is to systematically mitigate node embedding degradation, enhance cross‑criteria representation consistency, and optimize contrastive learning effectiveness by introducing dynamic noise augmentation, a progressive fusion mechanism, and a neighbor‑similarity‑based anchor selection strategy, thereby significantly improving the rating prediction accuracy and generalization capability of multi‑criteria recommender systems in sparse interaction environments.
On the technical implementation side, the model first constructs a user item bipartite graph for each evaluation criterion independently and normalizes the adjacency relationships using a layer wise trained bipartite graph neural network matrix, so as to preserve the independent rating distribution characteristics of each criterion. To tackle the degradation phenomenon where long tail items' embeddings converge towards head items due to sparse neighborhoods, a Gaussian noise enhanced LightGCN module is designed: during each layer of graph convolution propagation, dynamic Gaussian noise with an initial intensity of 0.2 and an exponential decay rate of 0.5 per training epoch is injected into the current layer's node embeddings. This perturbation does not alter the graph topology but acts solely on the feature space, thereby breaking feature homogenization and encouraging a more uniform embedding distribution for long tail items. To fuse the complementary advantages of graph attention networks in capturing fine grained local interactions and graph convolutional networks in perceiving global structural patterns, a progressive fusion mechanism is proposed. At each propagation layer, the multi head attention outputs from GAT and the neighborhood aggregation outputs from LightGCN are concatenated, and a learnable parameter adaptively controls the contribution of each layer, achieving hierarchical fusion from low level local details to high level global semantics. To overcome the difficulty of reliably selecting contrastive learning anchors caused by the inconsistency between rating criteria and samples in multi criteria data, an anchor selection strategy based on average neighbor cosine similarity is designed: within each criterion view, the average similarity between each node's embedding and those of all its neighbors is computed, and the node with the highest similarity is selected as the anchor for that view, serving as a stable contrastive benchmark. On this basis, a dual contrastive learning task is constructed—the local contrastive loss maximizes the consistency of positive sample embeddings of the same node across different criteria while pushing away negative samples, and the global contrastive loss enhances cross criterion alignment among global embeddings (node means) of each criterion. These two losses are jointly optimized, and the total loss function combines the local loss, global loss, and an L₂ regularization term, balancing node level discriminability and distribution level consistency.
To validate the model's effectiveness, experiments are conducted on three publicly available real‑world datasets: Yahoo!Movies, BeerAdvocate, and TripAdvisor. Yahoo!Movies contains 6,078 users, 976 movies, and 758,405 four‑criterion ratings; BeerAdvocate comprises 8,831 users, 2,698 beers, and 3,880,359 four‑criterion ratings; TripAdvisor includes 15,000 users, 1,325 hotels, and 20,830 seven‑criterion ratings, with a high sparsity level. Using mean absolute error and root mean square error as evaluation metrics, the proposed NGCLR is compared against more than ten baseline methods, including BMF, MSVD, MLR, SVR, CIC, DMCF, CFM, DNN‑MF, MCAE‑FADNN, and the best‑performing baseline D‑MGAC. Experimental results show that NGCLR achieves MAE and RMSE of 0.6028 and 0.8211 on Yahoo!Movies, corresponding to relative reductions of 2.94% and 3.79% over D‑MGAC; on BeerAdvocate, the values are 0.3931 and 0.5380, with relative reductions of 4.93% and 2.73%; and on TripAdvisor, they are 0.7338 and 0.9724, with relative reductions of 2.04% and 1.96%. Ablation studies demonstrate that removing the noise augmentation module, the progressive fusion mechanism, or the contrastive learning module leads to varying degrees of increase in both MAE and RMSE. In particular, the variant adopting a random anchor selection strategy yields MAE values that are 2.86%, 2.21%, and 0.69% higher than the full model on the three datasets, respectively, confirming the independent contributions and synergistic gains of each core component. Hyperparameter analysis indicates that the optimal performance is achieved with an embedding dimension of 256, 8 attention heads, and equal weights of 0.5 for both local and global contrastive losses; the dynamic decay noise strategy outperforms fixed‑noise and standard‑adaptive‑noise strategies, and the neighbor‑similarity‑based anchor selection surpasses both global‑average‑similarity and PageRank‑based strategies. Head‑vs‑tail group experiments show that the model achieves significantly greater MAE improvements on tail item groups than on head groups, and noise enhancement visualization further confirms that the embedding distribution of long‑tail items shifts from clustering towards dispersion. In summary, NGCLR effectively addresses the three major challenges in multi‑criteria recommendation—long‑tail degradation, insufficient fusion of graph modules, and anchor bias in contrastive learning—achieving consistently superior prediction accuracy across multiple real datasets, and thus provides an efficient and robust solution for multi‑criteria recommender systems.