Deep Active Learning with Manifold-preserving Trajectory Sampling
Yingrui Ji, Vijaya Sindhoori Kaza, Nishanth Artham, and Tianyang Wang

TL;DR
This paper introduces Manifold-Preserving Trajectory Sampling (MPTS), a novel active learning method that reduces bias in data selection by aligning feature space distributions, leading to improved model performance across vision and non-vision datasets.
Contribution
The paper proposes MPTS, a new active learning approach that enforces manifold preservation in feature space to correct bias from labeled data, enhancing data selection quality.
Findings
MPTS outperforms existing active learning methods on multiple benchmarks.
The method effectively reduces bias in data selection.
Experimental results show significant performance improvements.
Abstract
Active learning (AL) is for optimizing the selection of unlabeled data for annotation (labeling), aiming to enhance model performance while minimizing labeling effort. The key question in AL is which unlabeled data should be selected for annotation. Existing deep AL methods arguably suffer from bias incurred by clabeled data, which takes a much lower percentage than unlabeled data in AL context. We observe that such an issue is severe in different types of data, such as vision and non-vision data. To address this issue, we propose a novel method, namely Manifold-Preserving Trajectory Sampling (MPTS), aiming to enforce the feature space learned from labeled data to represent a more accurate manifold. By doing so, we expect to effectively correct the bias incurred by labeled data, which can cause a biased selection of unlabeled data. Despite its focus on manifold, the proposed method can…
Peer Reviews
Decision·ICLR 2026 Conference Withdrawn Submission
1. Trajactory-based sampling ensures sampling diversity and is faster than ensembled methods. 2. The model outperform other baselines on lots of tasks, such as SVHN, CIFAR10 and two tabular datasets --OpenML-6 and OpenML-155.
1. The trade-off between computational cost and model performance gain wasn't well established. Eventhough the author provided their complexity analysis in section 3.3, it would be more direct if we can see the wall-clock time of sampling time for MPTS and other benchmarks. 2. The advantage of using MPTS becomes minor when it comes to pretraining tasks. And the current experiments scope are limited to toy image/tabular/video data. I'm not sure about its impact in more realistic scenarios. 3. Th
Although the selection bias in active learning is not a new concept, the paper provides a fresh angle with the analysis in section 3.1. The manifold-preserving regularization aligns well with the analysis. The experiments are conducted on multiple datasets with a variety of feature sizes and model backbones as well. The proposed method shows a good advantage in the given settings.
1. The theoretical analysis is not clear enough. Equation (9) is too general and not informative. Equation (11) uses strong assumptions without much specification. Equation (12) is only verified empirically. The second strategy, the trajectory-based parameter sampling, is also a largely heuristic approach and weakens the connection between the theoretical motivation and proposed method. 2. There is too little analysis on the active sampling process. While the manifold perspective is somewhat n
1. The discussion of the issue raised by existing AL methods is motivated. 2. The proposed method is model-agnostic and can be easily integrated into existing AL frameworks.
1. The claim in Line 169-170, "Since existing methods only use biased labeled data L to learn feature representations" is not rigorous, as many existing AL methods also adopt unlabeled samples for learning feature representations. 2. The intuition behind the choice of MMD distance is missing. 3. It is unclear how to calculate Equation 8. More details are necessary. 4. The proposed method seems to be incremental, as MMD for manifold learning and stochastic Weight Averaging (SWA) for active learn
Strengths Method supported by theoretical foundations in Bayesian inference Empirical results show advantage of the method over selected baselines The trajectory-based sampling seems like a novel method.
Weaknesses 1. Active learning aims at optimizing the tradeoff between labeling effort and model accuracy. However, if we sample in a certain class distribution location that is not close to the decision boundary, I claim that this is a redundant sampling. The authors criterion to map distributions may result in redundant sampling, in my view. I would have much preferred it if the authors would introduce the well-known sampling tradeoff of exploration-exploitation in which the context of their w
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Taxonomy
TopicsMachine Learning and Algorithms · Robot Manipulation and Learning · Robotic Mechanisms and Dynamics
MethodsFocus
