Sequential recommendation is an important task to predict the next-item to access based on a sequence of interacted items. Most existing works learn user preference as the transition pattern from the previous item to the next one, ignoring the time interval between these two items. However, we observe that the time interval in a sequence may vary significantly different, and thus result in the ineffectiveness of user modeling due to the issue of \emph{preference drift}. In fact, we conducted an empirical study to validate this observation, and found that a sequence with uniformly distributed time interval (denoted as uniform sequence) is more beneficial for performance improvement than that with greatly varying time interval. Therefore, we propose to augment sequence data from the perspective of time interval, which is not studied in the literature. Specifically, we design five operators (Ti-Crop, Ti-Reorder, Ti-Mask, Ti-Substitute, Ti-Insert) to transform the original non-uniform sequence to uniform sequence with the consideration of variance of time intervals. Then, we devise a control strategy to execute data augmentation on item sequences in different lengths. Finally, we implement these improvements on a state-of-the-art model CoSeRec and validate our approach on four real datasets. The experimental results show that our approach reaches significantly better performance than the other 11 competing methods. Our implementation is available: https://github.com/KingGugu/TiCoSeRec.

In this paper, we propose an end-to-end Retrieval-Augmented Visual Language Model (REVEAL) that learns to encode world knowledge into a large-scale memory, and to retrieve from it to answer knowledge-intensive queries. REVEAL consists of four key components: the memory, the encoder, the retriever and the generator. The large-scale memory encodes various sources of multimodal world knowledge (e.g. image-text pairs, question answering pairs, knowledge graph triplets, etc) via a unified encoder. The retriever finds the most relevant knowledge entries in the memory, and the generator fuses the retrieved knowledge with the input query to produce the output. A key novelty in our approach is that the memory, encoder, retriever and generator are all pre-trained end-to-end on a massive amount of data. Furthermore, our approach can use a diverse set of multimodal knowledge sources, which is shown to result in significant gains. We show that REVEAL achieves state-of-the-art results on visual question answering and image captioning.

Pandemic(epidemic) modeling, aiming at disease spreading analysis, has always been a popular research topic especially following the outbreak of COVID-19 in 2019. Some representative models including SIR-based deep learning prediction models have shown satisfactory performance. However, one major drawback for them is that they fall short in their long-term predictive ability. Although graph convolutional networks (GCN) also perform well, their edge representations do not contain complete information and it can lead to biases. Another drawback is that they usually use input features which they are unable to predict. Hence, those models are unable to predict further future. We propose a model that can propagate predictions further into the future and it has better edge representations. In particular, we model the pandemic as a spatial-temporal graph whose edges represent the transition of infections and are learned by our model. We use a two-stream framework that contains GCN and recursive structures (GRU) with an attention mechanism. Our model enables mobility analysis that provides an effective toolbox for public health researchers and policy makers to predict how different lock-down strategies that actively control mobility can influence the spread of pandemics. Experiments show that our model outperforms others in its long-term predictive power. Moreover, we simulate the effects of certain policies and predict their impacts on infection control.

Training labels for graph embedding algorithms could be costly to obtain in many practical scenarios. Active learning (AL) algorithms are very helpful to obtain the most useful labels for training while keeping the total number of label queries under a certain budget. The existing Active Graph Embedding framework proposes to use centrality score, density score, and entropy score to evaluate the value of unlabeled nodes, and it has been shown to be capable of bringing some improvement to the node classification tasks of Graph Convolutional Networks. However, when evaluating the importance of unlabeled nodes, it fails to consider the influence of existing labeled nodes on the value of unlabeled nodes. In other words, given the same unlabeled node, the computed informative score is always the same and is agnostic to the labeled node set. With the aim to address this limitation, in this work, we introduce 3 dissimilarity-based information scores for active learning: feature dissimilarity score (FDS), structure dissimilarity score (SDS), and embedding dissimilarity score (EDS). We find out that those three scores are able to take the influence of the labeled set on the value of unlabeled candidates into consideration, boosting our AL performance. According to experiments, our newly proposed scores boost the classification accuracy by 2.1% on average and are capable of generalizing to different Graph Neural Network architectures.

两视图知识图（kgs）共同表示两个组成部分：抽象和常识概念的本体论观点，以及针对本体论概念实例化的特定实体的实例视图。因此，这些kg包含来自实例视图的本体学和周期性的分层的异质结构。尽管KG中有这些不同的结构，但最新的嵌入KG的作品假设整个KG仅属于两个观点之一，但并非同时属于。对于寻求将KG视为两种视图的作品，假定实例和本体论的观点属于相同的几何空间，例如所有嵌入在同一欧几里得空间中的节点或非欧盟产品空间，不再是合理的。对于两视图kg，图表的不同部分显示出不同的结构。为了解决这个问题，我们定义并构建了一个双几何空间嵌入模型（DGS），该模型通过将KG的不同部分嵌入不同的几何空间中，该模型使用复杂的非欧盟几何几何空间进行对两视图KGS进行建模。 DGS利用球形空间，双曲线空间及其在统一框架中学习嵌入的框架中的相交空间。此外，对于球形空间，我们提出了直接在球形空间中运行的新型封闭的球形空间操作员，而无需映射到近似切线空间。公共数据集上的实验表明，DGS在KG完成任务上的先前最先进的基线模型明显优于先前的基线模型，这表明了其在KGS中更好地建模异质结构的能力。

美国的意识形态分裂在日常交流中变得越来越突出。因此，关于政治两极分化的许多研究，包括最近采取计算观点的许多努力。通过检测文本语料库中的政治偏见，可以尝试描述和辨别该文本的两极分性。从直觉上讲，命名的实体（即，用作名词的名词和短语）和文本中的标签经常带有有关政治观点的信息。例如，使用“支持选择”一词的人可能是自由的，而使用“亲生生命”一词的人可能是保守的。在本文中，我们试图揭示社交媒体文本数据中的政治极性，并通过将极性得分分配给实体和标签来量化这些极性。尽管这个想法很简单，但很难以可信赖的定量方式进行这种推论。关键挑战包括少数已知标签，连续的政治观点，以及在嵌入单词媒介中的极性得分和极性中性语义含义的保存。为了克服这些挑战，我们提出了极性感知的嵌入多任务学习（PEM）模型。该模型包括（1）自制的上下文保护任务，（2）基于注意力的推文级别的极性推导任务，以及（3）对抗性学习任务，可促进嵌入式的极性维度及其语义之间的独立性方面。我们的实验结果表明，我们的PEM模型可以成功学习极性感知的嵌入。我们检查了各种应用，从而证明了PEM模型的有效性。我们还讨论了我们的工作的重要局限性，并在将PEM模型应用于现实世界情景时的压力谨慎。

最近的进步表明，使用强化学习和搜索来解决NP-HARD相关的任务的成功，例如旅行推销员优化，图表编辑距离计算等。但是，尚不清楚如何有效，准确地检测到如何有效地检测大型目标图中的一个小查询图，它是图数据库搜索，生物医学分析，社交组发现等中的核心操作。此任务称为子图匹配，本质上是在查询图和大型目标图之间执行子图同构检查。解决这个经典问题的一种有前途的方法是“学习进行搜索”范式，其中强化学习（RL）代理人的设计具有学习的政策，以指导搜索算法以快速找到解决方案而无需任何解决方案实例进行监督。但是，对于子图匹配的特定任务，尽管查询图通常由用户作为输入给出，但目标图通常更大。它为神经网络设计带来了挑战，并可能导致解决方案和奖励稀疏性。在本文中，我们提出了两项​​创新的N-BLS来应对挑战：（1）一种新颖的编码器折线神经网络体系结构，以动态计算每个搜索状态下查询和目标图之间的匹配信息； （2）蒙特卡洛树搜索增强了双层搜索框架，用于培训政策和价值网络。在五个大型现实世界目标图上进行的实验表明，N-BLS可以显着改善子图匹配性能。

Explaining machine learning models is an important and increasingly popular area of research interest. The Shapley value from game theory has been proposed as a prime approach to compute feature importance towards model predictions on images, text, tabular data, and recently graph neural networks (GNNs) on graphs. In this work, we revisit the appropriateness of the Shapley value for GNN explanation, where the task is to identify the most important subgraph and constituent nodes for GNN predictions. We claim that the Shapley value is a non-ideal choice for graph data because it is by definition not structure-aware. We propose a Graph Structure-aware eXplanation (GStarX) method to leverage the critical graph structure information to improve the explanation. Specifically, we define a scoring function based on a new structure-aware value from the cooperative game theory proposed by Hamiache and Navarro (HN). When used to score node importance, the HN value utilizes graph structures to attribute cooperation surplus between neighbor nodes, resembling message passing in GNNs, so that node importance scores reflect not only the node feature importance, but also the node structural roles. We demonstrate that GStarX produces qualitatively more intuitive explanations, and quantitatively improves explanation fidelity over strong baselines on chemical graph property prediction and text graph sentiment classification.

有效的模型选择，用于向下游任务识别合适的预先训练的神经网络是深度学习中的基本但具有挑战性的任务。目前的实践需要昂贵的计算成本在模型训练中进行性能预测。在本文中，我们通过在训练期间分析突触连接（边缘）的控制动态来提出一个新颖的神经网络选择框架。我们的框架是基于神经网络培训期间的回波传播相当于突触连接的动态演变。因此，融合的神经网络与由那些边缘组成的网络系统的平衡状态相关联。为此，我们构建一个网络映射$ \ phi $，将神经网络$ g_a $转换为定向行图$ g_b $，它在$ g_a $中定义。接下来，我们推导出神经电容度量标准$ \ beta _ {\ rm upf} $普遍捕获下游任务上的预测措施，仅使用少数早期训练结果。我们使用17个流行的预先训练的Imagenet模型和五个基准数据集进行了广泛的实验，包括CiFar10，CiFar100，SVHN，时尚Mnist和鸟类，以评估我们框架的微调性能。我们的神经电容度量显示为仅基于早期训练结果的模型选择的强大指标，比最先进的方法更有效。

高级综合（HLS）释放了计算机架构师以非常低级的语言开发他们的设计，并需要准确指定如何在寄存器级别传输数据。在HLS的帮助下，硬件设计人员必须只描述设计的高级行为流程。尽管如此，它仍然可能需要数周才能开发高性能架构，主要是因为在更高的水平下有许多设计选择需要更多的时间来探索。它还需要几分钟才能从HLS工具上获得每个设计候选人的质量的反馈。在本文中，我们建议通过使用培训的图形神经网络（GNN）来建立HLS工具来解决这个问题，该工具被培训用于广泛的应用程序。实验结果表明，通过采用基于GNN的模型，我们能够以高精度估计毫秒的设计质量，这可以帮助我们非常快速地搜索解决方案空间。