Due to the long-range modeling ability and linear complexity property, Mamba has attracted considerable attention in point cloud analysis. Despite some interesting progress, related work still suffers from imperfect point cloud serialization, insufficient high-level geometric perception, and overfitting of the selective state space model (S6) at the core of Mamba. To this end, we resort to an SSM-based point cloud network termed CloudMamba to address the above challenges. Specifically, we propose sequence expanding and sequence merging, where the former serializes points along each axis separately and the latter serves to fuse the corresponding higher-order features causally inferred from different sequences, enabling unordered point sets to adapt more stably to the causal nature of Mamba without parameters. Meanwhile, we design chainedMamba that chains the forward and backward processes in the parallel bidirectional Mamba, capturing high-level geometric information during scanning. In addition, we propose a grouped selective state space model (GS6) via parameter sharing on S6, alleviating the overfitting problem caused by the computational mode in S6. Experiments on various point cloud tasks validate CloudMamba's ability to achieve state-of-the-art results with significantly less complexity.

Many practical time series forecasting (TSF) tasks are plagued by data limitations. To alleviate this challenge, we design a data-level augmentation framework. It involves a time series generation (TSG) module and a source data selection (Sel-src) module. TSG aims to achieve better generation results by considering both the global profile and temporal dynamics of series. However, when only few target data is available, TSG module may tend to simulate the limited target samples, leading to poor generalization performance. A natural idea for this problem is to seek help from related source domain, which can provide additional useful information for TSG module. Here we consider a more complex situation, where the relevance between source and target domains is ambiguous. That is, irrelevant samples may exist in the source domain. Blindly using all the source data may lead to counterproductive results. To meet this challenge, Sel-src module is designed to select effective source samples by Inter-Representation Learning (Inter-RL) and Intra-Representation Learning (Intra-RL). Effectiveness of this algorithm is underpinned from two aspects: the quality of the augmented data and the accuracy improvement upon the augmentation.

Time series forecasting (TSF) has gained significant attention as a widely explored research area in diverse applications. Existing methods, which focus on improvements in the most common scenarios, focus little on performance in rare cases. Despite their scarce occurrences in the data, these rare samples are more challenging and easily overlooked by models, significantly contributing to the total loss. In this paper, we propose a novel approach (dubbed iBACon) that overcomes this limitation by employing imbalance-aware contrastive learning and trend-seasonal decomposition architecture, specifically designed to solve TSF. To this end, we first introduce the Input-Output Difference (IOD) metric as a pseudo-label and reveal the data imbalance phenomenon in TSF. This label continuity inherently provides a meaningful distance between targets, implying a similarity between nearby targets in both label and feature spaces. Based on this similarity, the proposed imbalance-aware contrastive loss aims to reshape feature embeddings to facilitate knowledge dissemination among challenging samples and learn specific predictive features. Finally, when combined with our trend-seasonal decomposition network, iBACon significantly improves TSF accuracy. Experiments show that iBACon enhances overall average accuracy and substantially improves the 1-3% most challenging samples.