Cross-Domain Sequential Recommendation (CDSR) is a hot topic in sequence-based user interest modeling, which aims at utilizing a single model to predict the next items for different domains. To tackle the CDSR, many methods are focused on domain overlapped users’ behaviors fitting, which heavily relies on the same user’s different-domain item sequences collaborating signals to capture the synergy of cross-domain item-item correlation. Indeed, these overlapped users occupy a small fraction of the entire user set only, which introduces a strong assumption that the small group of domain overlapped users is enough to represent all domain user behavior characteristics. However, intuitively, such a suggestion is biased, and the insufficient learning paradigm in non-overlapped users will inevitably limit model performance. Further, it is not trivial to model non-overlapped user behaviors in CDSR because there are no other domain behaviors to collaborate with, which causes the observed single-domain users’ behavior sequences to be hard to contribute to cross-domain knowledge mining. Considering such a phenomenon, we raise a challenging and unexplored question: How to unleash the potential of non-overlapped users’ behaviors to empower CDSR? To this end, we propose a novel CDSR framework with Neural Processes (NP), briefly termed CDSRNP, where NP combines the advantages of meta-learning and stochastic processes. As a meta-learning based method, we first sample some observed overlapped users’ behaviors as the support set to empower query users’ prediction. Next, we employ the NP principle to align the cross-domain correlation prior/posterior distributions generated by support/query user sets, thus the query user (e.g., non-overlapped user) behaviors sequence could also establish a straight bridge to connect other domain items. Additionally, we design a fine-grained interest adaptive layer to identify the users’ interests to enhance prediction. Experimental results illustrate that CDSRNP1 outperforms state-of-the-art methods in two real-world datasets.

In real-world applications, users express different behaviors when they interact with different items, including implicit click/like interactions, and explicit comments/reviews interactions. Nevertheless, almost all recommender works are focused on how to describe user preferences by the implicit click/like interactions, to find the synergy of people. For the content-based explicit comments/reviews interactions, some works attempt to utilize them to mine the semantic knowledge to enhance recommender models. However, they still neglect the following two points: (1) The content semantic is a universal world knowledge; how do we extract the multi-aspect semantic information to empower different domains? (2) The user/item ID feature is a fundamental element for recommender models; how do we align the ID and content semantic feature space? In this paper, we propose a 'plugin' semantic knowledge transferring method LoID, which includes two major components: (1) LoRA-based large language model pretraining to extract multi-aspect semantic information; (2) ID-based contrastive objective to align their feature spaces. We conduct extensive experiments with SOTA baselines to demonstrate superiority of our method LoID.

Deep learning models have been widely applied in many fields, including medical image analysis and computer-aided disease diagnosis. However, these models are easily fooled by adversarial attacks from some created adversarial examples which are hardly distinguished by humans. In this paper, we implement a comprehensive assessment of six popular adversarial attacks on four multimodal medical image datasets using two main deep learning-based target models. Moreover, in order to evaluate the capability of defense, two new defense methods are leveraged to cope with medical adversarial attacks. More importantly, we also build and release a big multimodal medical adversarial database (including four medical adversarial datasets) with 712,596 examples to facilitate future research of adversarial attacks and defenses in the multimodal medical image field. Extensive experiments indicate that all-sided adversarial attacks like BIM are still scarce under different evaluation metrics and defenses are not universally successful.