Negative sampling plays a critical role in collaborative filtering (CF), as it accelerates convergence and improves recommendation accuracy. Among recent studies, mixup-based negative sampling has shown promising performance. However, existing methods primarily focus on increasing the similarity between the synthesized negative and the positive item, without considering the false positive issue commonly found in implicit feedback scenarios. Blindly training all positive samples with overly hard negatives can magnify the impact of false positives and hurt recommendation performance. To address this challenge, we first provide a theoretical analysis revealing that mixup-synthesized hard negatives implicitly reweight the similarity difference between the user's interactions and both the positive and negative boundaries, thereby shaping the training signal. Motivated by this, we propose a novel strategy named Dual Context-Aware Negative Sampling (DCANS), which enhances each positive item by assessing its alignment with the user's interest context, and simultaneously adjusts the hardness of synthesized negatives based on their relevance to the same interest context. This strategy optimizes the training direction toward the user's genuine preferences, mitigating the negative impact of false positives while preserving the benefits of hard negative sampling. Extensive experiments on three benchmark datasets demonstrate that our method achieves consistent improvements over state-of-the-art baselines. Our PyTorch implementation is available https://github.com/Wu-Xi/DCANS.

Recent years have witnessed a variety of applications of gaming video coding, while how to improve the coding efficiency has been relatively under-explored. The state-of-the-art video coding standard, Versatile Video Coding (VVC), adopts the Reference Picture Resampling (RPR) which allows the variation of the frame resolutions in encoding/decoding. The great flexibility supported by RPR motivates us to develop a bidirectional quality impulse based guidance scheme, in an effort to fully exploit the potential of RPR in gaming video coding. The design philosophy involves reducing the data volume on the encoder side through selective downsampling, and enhancing reconstruction by harnessing quality conveyance from neighboring frames. More specifically, a new RPR structure is developed based on the underlying philosophy that the periodic quality impulse could promisingly boost the quality of the whole sequence. On top of the developed structure, we propose a bidirectional guidance model that faithfully enhances video quality by resorting to frames with quality impulse. Experimental results exhibit the proposed scheme can achieve significant bit-rate savings for gaming videos.

Vision transformers have significantly advanced the field of computer vision in recent years. The cornerstone of these transformers is the multi-head attention mechanism, which models interactions between visual elements within a feature map. However, the vanilla multi-head attention paradigm independently learns parameters for each head, which ignores crucial interactions across different attention heads and may result in redundancy and under-utilization of the model’s capacity. To enhance model expressiveness, we propose a novel nested attention mechanism, Ne-Att, that explicitly models cross-head interactions via a hierarchical variational distribution. We conducted extensive experiments on image classification, and the results demonstrate the superiority of Ne-Att.

Cross-Domain Recommendation (CDR) is capable of incorporating auxiliary information from multiple domains to advance recommendation performance. Conventional CDR methods primarily rely on overlapping users, whereby knowledge is conveyed between the source and target identities belonging to the same natural person. However, such a heuristic assumption is not universally applicable due to an individual may exhibit distinct or even conflicting preferences in different domains, leading to potential noises. In this paper, we view the anchor links between users of various domains as the learnable parameters to learn the task-relevant cross-domain correlations. A novel optimal transport based model ALCDR is further proposed to precisely infer the anchor links and deeply aggregate collaborative signals from the perspectives of intra-domain and inter-domain. Our proposal is extensively evaluated over real-world datasets, and experimental results demonstrate its superiority.

Massive open online courses (MOOCs), which offer open access and widespread interactive participation through the internet, are quickly becoming the preferred method for online and remote learning. Several MOOC platforms offer the service of course recommendation to users, to improve the learning experience of users. Despite the usefulness of this service, we consider that recommending courses to users directly may neglect their varying degrees of expertise. To mitigate this gap, we examine an interesting problem of concept recommendation in this paper, which can be viewed as recommending knowledge to users in a fine-grained way. We put forward a novel approach, termedHinCRec-RL, forConceptRecommendation in MOOCs, which is based onHeterogeneousInformationNetworks andReinforcementLearning. In particular, we propose to shape the problem of concept recommendation within a reinforcement learning framework to characterize the dynamic interaction between users and knowledge concepts in MOOCs. Furthermore, we propose to form the interactions among users, courses, videos, and concepts into aheterogeneous information network (HIN)to learn the semantic user representations better. We then employ an attentional graph neural network to represent the users in the HIN, based on meta-paths. Extensive experiments are conducted on a real-world dataset collected from a Chinese MOOC platform,XuetangX, to validate the efficacy of our proposed HinCRec-RL. Experimental results and analysis demonstrate that our proposed HinCRec-RL performs well when compared with several state-of-the-art models.