Visible-infrared person re-identification (VI-ReID) has raised more attention in night-time surveillance applications due to the struggle to capture valid appearance information under poor illumination conditions via visible cameras. Existing works usually separate the modality-specific and modality-irrelevant information in visible and infrared features, or project features of two modalities into a unified embedding feature space directly, which aims to eliminate huge modality discrepancies. However, these methods neglect the intra-modality and inter-modality correlations. We argue that the correlations can implicitly guide the network to discover the modality-irrelevant information, thus more beneficial for eliminating huge modality discrepancies and preserving individual differences. To this end, we propose a novel framework, termed as correlation-guided semantic consistency network (CSC-Net), to explore and exploit the intra-modality and inter-modality correlations. Specifically, CSC-Net consists of a cross-modality semantic alignment (CSA) module, a cross-granularity discrepancy awareness (CDA) module, and a probability consistency constraint (PCC) module. CSA mines the inter-modality correlation by calculating the semantic similarity between modalities to explore modality-irrelevant features, and then transfers the learned features to the backbone network to face the input of only single modality images. To preserve the individual differences, CDA sufficiently utilizes the intra-modality correlation via exploring the multi-granularity discriminative information. Finally, PCC constrains the network at the probability level, cooperating with the CSA which constrains at the feature level, to further alleviate the modality discrepancy. Extensive experiments on two public VI-ReID datasets SYSU-MM01 and RegDB have verified the effectiveness of our approach.

Hard-label textual adversarial attack is a challenging task, as only the predicted label information is available, and the text space is discrete and non-differentiable. Relevant research work is still in fancy and just a handful of methods are proposed. However, existing methods suffer from either the high complexity of genetic algorithms or inaccurate gradient estimation, thus are arduous to obtain adversarial examples with high semantic similarity and low perturbation rate under the tight-budget scenario. In this paper, we propose a simple and sweet paradigm for hard-label textual adversarial attack, named SSPAttack. Specifically, SSPAttack first utilizes initialization to generate an adversarial example, and removes unnecessary replacement words to reduce the number of changed words. Then it determines the replacement order and searches for an anchor synonym, thus avoiding going through all the synonyms. Finally, it pushes substitution words towards original words until an appropriate adversarial example is obtained. The core idea of SSPAttack is just swapping words whose mechanism is simple. Experimental results on eight benchmark datasets and two real-world APIs have shown that the performance of SSPAttack is sweet in terms of similarity, perturbation rate and query efficiency.

Distribution estimation has been demonstrated as one of the most effective approaches in dealing with few-shot image classification, as the low-level patterns and underlying representations can be easily transferred across different tasks in computer vision domain. However, directly applying this approach to few-shot text classification is challenging, since leveraging the statistics of known classes with sufficient samples to calibrate the distributions of novel classes may cause negative effects due to serious category difference in text domain. To alleviate this issue, we propose two simple yet effective strategies to estimate the distributions of the novel classes by utilizing unlabeled query samples, thus avoiding the potential negative transfer issue. Specifically, we first assume a class or sample follows the Gaussian distribution, and use the original support set and the nearest few query samples to estimate the corresponding mean and covariance. Then, we augment the labeled samples by sampling from the estimated distribution, which can provide sufficient supervision for training the classification model. Extensive experiments on eight few-shot text classification datasets show that the proposed method outperforms state-of-the-art baselines significantly.