CAT: Can Trust be Predicted with Context-Awareness in Dynamic Heterogeneous Networks?
Organizations: State Key Laboratory of Integrated Services Networks, School of Cyber Engineering, Xidian University · Hangzhou Institute of Technology, Xidian University · Department of Computer Science, Purdue University
Abstract
Trust prediction provides valuable support for decision-making, risk mitigation, and system security enhancement. Recently, Graph Neural Networks (GNNs) have emerged as a promising approach for trust prediction, owing to their ability to learn expressive node representations that capture intricate trust relationships within a network. However, current GNN-based trust prediction models face several limitations: (i) Most of them fail to capture trust dynamicity, leading to questionable inferences. (ii) They rarely consider the heterogeneous nature of real-world networks, resulting in a loss of rich semantics. (iii) None of them support context-awareness, a basic property of trust, making prediction results coarse-grained. To this end, we propose CAT, the first Context-Aware GNN-based Trust prediction model that supports trust dynamicity and accurately represents real-world heterogeneity. CAT consists of a graph construction layer, an embedding layer, a heterogeneous attention layer, and a prediction layer. It handles dynamic graphs using continuous-time representations and captures temporal information through a time encoding function. To model graph heterogeneity and leverage semantic information, CAT employs a dual attention mechanism that identifies the importance of different node types and nodes within each type. For context-awareness, we introduce a new notion of meta-paths to extract contextual features. By constructing context embeddings and integrating a context-aware aggregator, CAT can predict both context-aware trust and overall trust. Extensive experiments on three real-world datasets demonstrate that CAT outperforms five groups of baselines in trust prediction, while exhibiting strong scalability to large-scale graphs and robustness against both trust-oriented and GNN-oriented attacks.
Figures & tables
| Models | Guardian [ 6 ] | Medley [ 7 ] | GATrust [ 8 ] | TrustGNN [ 9 ] | KGTrust [ 10 ] | DTrust [ 11 ] | TrustGuard [ 2 ] | CAT |
| Dynamicity | ○ | ● | ○ | ○ | ○ | ● | ● | ● |
| Heterogeneity | ○ | ○ | ○ | ○ | ● | ○ | ○ | ● |
| Context-Awareness | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ● |
| Robustness | ○ | ○ | ○ | ○ | ○ | ○ | ◐ | ● |
| Datasets | # Users | # Items | # Ratings | # Trust relationships | # Contexts | Timestamps of ratings | Timestamps of trust relationships |
| Epinions | 9163 | 12573 | 265189 | 311158 | 25 | ✓ | ✓ |
| Ciao | 2378 | 16861 | 36065 | 57544 | 6 | ✓ | ✗ |
| CiaoDVD | 19533 | 16121 | 72665 | 40133 | 17 | ✓ | ✗ |
| CAT and variants | Epinions: Observed users | Epinions: Unobserved users | Ciao | ||||||
| MRR | AP | AUC | MRR | AP | AUC | MRR | AP | AUC | |
| CAT | 0.6025 | 0.9383 | 0.9677 | 0.4082 | 0.9527 | 0.8933 | 0.4150 | 0.9234 | 0.9327 |
| w/o Time Embedding | 0.5575 | 0.9240 | 0.9597 | 0.2441 | 0.9040 | 0.8045 | 0.3702 | 0.9050 | 0.9142 |
| w/o Type Attention | 0.5941 | 0.9368 | 0.9677 | 0.3033 | 0.9393 | 0.8776 | 0.4035 | 0.9216 | 0.9322 |
| w/o Node Attention | 0.5781 | 0.9328 | 0.9653 | 0.3975 | 0.9501 | 0.8851 | 0.4042 | 0.9194 | 0.9293 |
| w/o Ca Meta-path | 0.5763 | 0.9274 | 0.9600 | 0.2924 | 0.9328 | 0.8592 | 0.3959 | 0.9157 | 0.9256 |
| CAT and variants | Epinions: Observed users | Epinions: Unobserved users | Ciao | ||||||
| MRR | AP | AUC | MRR | AP | AUC | MRR | AP | AUC | |
| CAT | 0.6025 | 0.9383 | 0.9677 | 0.4082 | 0.9527 | 0.8933 | 0.4150 | 0.9234 | 0.9327 |
| w/o Time Embedding | 0.5575 | 0.9240 | 0.9597 | 0.2441 | 0.9040 | 0.8045 | 0.3702 | 0.9050 | 0.9142 |
| w/o Type Attention | 0.5941 | 0.9368 | 0.9677 | 0.3033 | 0.9393 | 0.8776 | 0.4035 | 0.9216 | 0.9322 |
| w/o Node Attention | 0.5781 | 0.9328 | 0.9653 | 0.3975 | 0.9501 | 0.8851 | 0.4042 | 0.9194 | 0.9293 |
| w/o Ca Meta-path | 0.5763 | 0.9274 | 0.9600 | 0.2924 | 0.9328 | 0.8592 | 0.3959 | 0.9157 | 0.9256 |
| Tasks | Models | Clean | Trust-oriented Attacks | GNN-oriented Attacks | ||||||||
| =5% | =10% | =15% | =20% | MDR | =5% | =10% | =15% | =20% | MDR | |||
| ① | Medley | 0.4762 | 0.4552 | 0.4367 | 0.4155 | 0.4079 | 14.34% | 0.4650 | 0.4576 | 0.4477 | 0.4393 | 7.75% |
| TrustGuard | 0.4955 | 0.4831 | 0.4820 | 0.4565 | 0.4528 | 8.62% | 0.4813 | 0.4711 | 0.4664 | 0.4721 | 5.87% | |
| CAT | 0.6025 | 0.5968 | 0.6046 | 0.6144 | 0.6070 | 0.95% | 0.5999 | 0.5869 | 0.5842 | 0.5821 | 3.39% | |
| ② | Medley | 0.1979 | 0.1894 | 0.1791 | 0.1756 | 0.1715 | 13.34% | 0.1909 | 0.1890 | 0.1846 | 0.1737 | 12.23% |
| TrustGuard | 0.2571 | 0.2465 | 0.2431 | 0.2253 | 0.2250 | 12.49% | 0.2477 | 0.2296 | 0.2348 | 0.2289 | 10.97% | |
Appendix figures & tables2 assets
Supplementary material from the paper’s appendix.
Appendix
| Metrics | Tasks | Models | Clean | Trust-oriented Attacks | GNN-oriented Attacks | ||||||||
| =5% | =10% | =15% | =20% | MDR | =5% | =10% | =15% | =20% | MDR | ||||
| AP | ① | Medley | 0.8944 | 0.8862 | 0.8855 | 0.8728 | 0.8613 | 3.70% | 0.8923 | 0.8838 | 0.8827 | 0.8810 | 1.50% |
| TrustGuard | 0.8919 | 0.8860 | 0.8855 | 0.8724 | 0.8685 | 2.62% | 0.8853 | 0.8816 | 0.8826 | 0.8814 | 1.18% | ||
| CAT | 0.9383 | 0.9394 | 0.9391 | 0.9415 | 0.9401 | -0.09% | 0.9399 | 0.9350 | 0.9326 | 0.9335 | 0.61% | ||
| ② | Medley | 0.8884 | 0.8714 | 0.8473 | 0.8430 | 0.8328 | 6.26% | 0.8799 | 0.8758 | 0.8780 | 0.8652 | 2.61% | |
| TrustGuard | 0.8950 | 0.8918 | 0.8918 | 0.8824 | 0.8802 | 1.65% | 0.8901 | 0.8881 | 0.8898 | 0.8881 | 0.77% | ||