Unsupervised domain adaptation (UDA) provides a strategy for improving machine learning performance in data-rich (target) domains where ground truth labels are inaccessible but can be found in related (source) domains. In cases where meta-domain information such as label distributions is available, weak supervision can further boost performance. We propose a novel framework, CALDA, to tackle these two problems. CALDA synergistically combines the principles of contrastive learning and adversarial learning to robustly support multi-source UDA (MS-UDA) for time series data. Similar to prior methods, CALDA utilizes adversarial learning to align source and target feature representations. Unlike prior approaches, CALDA additionally leverages cross-source label information across domains. CALDA pulls examples with the same label close to each other, while pushing apart examples with different labels, reshaping the space through contrastive learning. Unlike prior contrastive adaptation methods, CALDA requires neither data augmentation nor pseudo labeling, which may be more challenging for time series. We empirically validate our proposed approach. Based on results from human activity recognition, electromyography, and synthetic datasets, we find utilizing cross-source information improves performance over prior time series and contrastive methods. Weak supervision further improves performance, even in the presence of noise, allowing CALDA to offer generalizable strategies for MS-UDA. Code is available at: https://github.com/floft/calda

提出一种新的框架 CALDA，将对比学习和对抗学习的原则相结合，用于多源自适应学习，特别是时间序列数据。与之前的方法不同，其中 CALDA 还利用跨源标签信息，通过对比学习重新塑造空间，推动相同标签的示例彼此靠近，将不同标签的示例分开。实现结果表明，使用交叉源信息使得 CALDA 在时间序列和对比方法方面的表现都有所提高。当存在噪声时，弱监督进一步提高了性能，允许 CALDA 提供可推广的 MS-UDA 策略。

使用对比度对抗学习改进多源时间序列域自适应