Fairness in recommendation has drawn much attention since it significantly affects how users access information and how information is exposed to users. However, most fairness-aware methods are designed offline with the entire stationary interaction data to handle the global unfairness issue and evaluate their performance in a one-time paradigm. In real-world scenarios, users tend to interact with items continuously over time, leading to a dynamic recommendation environment where unfairness is evolving online. Moreover, previous methods that focus on mitigating the unfairness can hardly bring significant improvements to the recommendation task. Hence, in this paper, we propose aModel-agnosticDual-sideOnlineFairness Learning method (MDOFair) for the dynamic recommendation. First, we carefully design dynamic dual-side fairness learning to trace the rapid evolution of unfairness from both the user and item sides. Second, we leverage the fairness and recommendation tasks in one utilized framework to pursue the double-win success. Last, we present an efficient model-agnostic post-ranking method for the dynamic recommendation scenario to mitigate the dynamic unfairness while improving the recommendation performance significantly. Extensive experiments demonstrate the superiority and effectiveness of our proposed MDOFair by incorporating it into existing dynamic models as a post-ranking stage.

Nowadays, many dynamic recommendations still suffer from the insufficiency of finding user online interest evolving patterns because of those complicated interactions. In general, each interaction is usually impacted by multiple underlying reasons, which needs us to open the “box” of each interaction instance instead of simply treating them as a pair-wise link. Besides, different users usually perform differently for their long-term and short-term tastes, leaving traditional sequential models far from personalized. In this article, we propose a novel recommendation model based on Graph Diffusion and Ebbinghaus Curve. Specifically, to explore the underline reasons for different interactions, we explore an underlying sub-graph for each interaction and find important reasoning paths within the sub-graph via a well-designed graph diffusion method. To capture users’ personalized strategies on long-term and short-term tastes, we are inspired by the Ebbinghaus Curve, which can naturally describe users’ memory patterns, and design an effective neural network to process users’ evolving behaviors. We conduct extensive experiments on four real-world datasets and the results further confirm the superiority of our model compared with existing state-of-the-art baselines.

Communication networks represent communication between entities like social networks and microservice call graphs of microservice systems. Link prediction is useful in various communication network service systems such as predicting the relation between two services. Continuous-time dynamic graph (CTDG) is one form of representing temporal information in communication networks that treats them as a set of events occurring over time. Dynamic graph embedding for CTDG handles these events and disseminates event information to other nodes to get node embedding. Though dynamic graph embedding is suitable for making link prediction in communication networks, graph embedding for CTDG faces challenges such as how to model the event information dissemination process including information decaying over distance and influence of time information. To cope with this issue, we propose a CTDG-based dynamic graph embedding framework for dynamic communication networks link prediction called CTDGNN (Continuous-Time Dynamic Graph Neural Networks). In particular, we propose a self-adaptive information dissemination strategy based on node importance to update node embedding by disseminating event information. Finally, extensive numerical experiments on three real-world communication network datasets validate the effectiveness of our proposed model compared to other related methods.