Yasir Khan, Xinlei Wu, Sangpil Youm, Justin Ho, Aryaan Mehboob Shaikh, Jairo Garciga, Rohan Sharma, Bonnie J Dorr. Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers). 2025.

Prompt Tuning has emerged as a prominent research paradigm for adapting vision-language models to various downstream tasks. However, recent research indicates that prompt tuning methods often lead to overfitting due to limited training samples. In this paper, we propose a Cross-modal Aligned Feature Tuning (CRAFT) method to address this issue. Cross-modal alignment is conducted by first selecting anchors from the alternative domain and deriving relative representations of the embeddings for the selected anchors. Optimizing for a feature alignment loss over anchor-aligned text and image modalities creates a more unified text-image common space. Overfitting in prompt tuning also deteriorates model performance on out-of-distribution samples. To further improve the prompt model's robustness, we propose minimizing Maximum Mean Discrepancy (MMD) over the anchor-aligned feature spaces to mitigate domain shift. The experiment on four different prompt tuning structures consistently shows the improvement of our method, with increases of up to 6.1% in the Base-to-Novel generalization task, 5.8% in the group robustness task, and 2.7% in the out-of-distribution tasks. The code is available at https://github.com/lingchensun/Craft.

Self-supervised learning through contrastive representations is an emergent and promising avenue, aiming at alleviating the availability of labeled data. Recent research in the field also demonstrates its viability for several downstream tasks, henceforth leading to works that implement the contrastive principle through innovative loss functions and methods. However, despite achieving impressive progress, most methods depend on prohibitively large batch sizes and compute requirements for good performance. In this work, we propose the $\textbf{AUC}$-$\textbf{C}$ontrastive $\textbf{L}$earning, a new approach to contrastive learning that demonstrates robust and competitive performance in compute-limited regimes. We propose to incorporate the contrastive objective within the AUC-maximization framework, by noting that the AUC metric is maximized upon enhancing the probability of the network's binary prediction difference between positive and negative samples which inspires adequate embedding space arrangements in representation learning. Unlike standard contrastive methods, when performing stochastic optimization, our method maintains unbiased stochastic gradients and thus is more robust to batchsizes as opposed to standard stochastic optimization problems. Remarkably, our method with a batch size of 256, outperforms several state-of-the-art methods that may need much larger batch sizes (e.g., 4096), on ImageNet and other standard datasets. Experiments on transfer learning, few-shot learning, and other downstream tasks also demonstrate the viability of our method.

Contrastive Learning (CL) plays a crucial role in molecular representation learning, enabling unsupervised learning from large scale unlabeled molecule datasets. It has inspired various applications in molecular property prediction and drug design. However, existing molecular representation learning methods often introduce potential false positive and false negative pairs through conventional graph augmentations like node masking and subgraph removal. The issue can lead to suboptimal performance when applying standard contrastive learning techniques to molecular datasets. To address the issue of false positive and negative pairs in molecular representation learning, we propose a novel probability-based contrastive learning (CL) framework. Unlike conventional methods, our approach introduces a learnable weight distribution via Bayesian modeling to automatically identify and mitigate false positive and negative pairs. This method is particularly effective because it dynamically adjusts to the data, improving the accuracy of the learned representations. Our model is learned by a stochastic expectation-maximization process, which optimizes the model by iteratively refining the probability estimates of sample weights and updating the model parameters. Experimental results indicate that our method outperforms existing approaches in 13 out of 15 molecular property prediction benchmarks in MoleculeNet dataset and 8 out of 12 benchmarks in the QM9 benchmark, achieving new state-of-the-art results on average.

Learning from noisy labels is an important and long-standing problem in machine learning for real applications. One of the main research lines focuses on learning a label corrector to purify potential noisy labels. However, these methods typically rely on strict assumptions and are limited to certain types of label noise. In this paper, we reformulate the label-noise problem from a generative-model perspective, *i.e.*, labels are generated by gradually refining an initial random guess. This new perspective immediately enables existing powerful diffusion models to seamlessly learn the stochastic generative process. Once the generative uncertainty is modeled, we can perform classification inference using maximum likelihood estimation of labels. To mitigate the impact of noisy labels, we propose the **L**abel-**R**etrieval-**A**ugmented (LRA) diffusion model, which leverages neighbor consistency to effectively construct pseudo-clean labels for diffusion training. Our model is flexible and general, allowing easy incorporation of different types of conditional information, *e.g.*, use of pre-trained models, to further boost model performance. Extensive experiments are conducted for evaluation. Our model achieves new state-of-the-art (SOTA) results on all the standard real-world benchmark datasets. Remarkably, by incorporating conditional information from the powerful CLIP model, our method can boost the current SOTA accuracy by 10-20 absolute points in many cases. Code is available: https://anonymous.4open.science/r/LRA-diffusion-5F2F

A fundamental question in software testing research is how to compare test suites, often as a means for comparing test-generation techniques that produce those test suites. Researchers frequently compare test suites by measuring their coverage . A coverage criterion C provides a set of test requirements and measures how many requirements a given suite satisfies. A suite that satisfies 100% of the feasible requirements is called C-adequate . Previous rigorous evaluations of coverage criteria mostly focused on such adequate test suites: given two criteria C and C ′, are C -adequate suites on average more effective than C ′-adequate suites? However, in many realistic cases, producing adequate suites is impractical or even impossible. This article presents the first extensive study that evaluates coverage criteria for the common case of non-adequate test suites: given two criteria C and C ′, which one is better to use to compare test suites? Namely, if suites T 1 , T 2 ,…, T n have coverage values c 1 , c 2 ,…, c n for C and c 1 ′, c 2 ′,…, c n ′ for C ′, is it better to compare suites based on c 1 , c 2 ,…, c n or based on c 1 ′, c 2 ′,…, c n ′ ? We evaluate a large set of plausible criteria, including basic criteria such as statement and branch coverage, as well as stronger criteria used in recent studies, including criteria based on program paths, equivalence classes of covered statements, and predicate states. The criteria are evaluated on a set of Java and C programs with both manually written and automatically generated test suites. The evaluation uses three correlation measures. Based on these experiments, two criteria perform best: branch coverage and an intraprocedural acyclic path coverage. We provide guidelines for testing researchers aiming to evaluate test suites using coverage criteria as well as for other researchers evaluating coverage criteria for research use.

A fundamental question in software testing research is how to compare test suites, often as a means for comparing test-generation techniques. Researchers frequently compare test suites by measuring their coverage. A coverage criterion C provides a set of test requirements and measures how many requirements a given suite satisfies. A suite that satisfies 100% of the (feasible) requirements is C-adequate.