Many reinforcement learning (RL) problems admit multiple terminal solutions of comparable quality, where the goal is not to identify a single optimum but to represent a diverse set of high-quality outcomes. Nevertheless, policies trained by standard expected return maximization routinely collapse onto a small subset of outcomes, a phenomenon commonly attributed to insufficient exploration or weak regularization. We show that this explanation is incomplete: outcome level mode collapse is a structural consequence of the expected-return objective itself. Under […]

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I thought that it would be nice to have short and concise summaries of recent projects handy, to share them with a more general audience, including colleagues and students. So, I challenged myself to use fewer than 1000 words without getting distracted by the nitty-gritty details and technical jargon. In this post, I mainly cover some of my recent research in collaboration with the [iPRoBe Lab](http://iprobe.cse.msu.edu) that falls under the broad category of developing approaches to hide specific […]

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Developing good predictive models hinges upon accurate performance evaluation and comparisons. However, when evaluating machine learning models, we typically have to work around many constraints, including limited data, independence violations, and sampling biases. Confidence intervals are no silver bullet, but at the very least, they can offer an additional glimpse into the uncertainty of the reported accuracy and performance of a model. This article outlines different methods for creating confidence intervals for machine learning models. Note that these […]

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Can a fully sovereign open reasoning model match state of the art systems when every part of its training pipeline is transparent. Researchers from Mohamed bin Zayed University of Artificial Intelligence (MBZUAI) release K2 Think V2, a fully sovereign reasoning model designed to test how far open and fully documented pipelines can push long horizon reasoning on math, code, and science when the entire stack is open and reproducible. K2 Think V2 takes the 70 billion parameter K2 […]

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The requirement for expert annotations limits the effectiveness of deep learning for medical image analysis. Although 3D self-supervised methods like volume contrast learning (VoCo) are powerful and partially address the labeling scarcity issue, their high computational cost and memory consumption are barriers. We propose 2D-VoCo, an efficient adaptation of the VoCo framework for slice-level self-supervised pre-training that learns spatial-semantic features from unlabeled 2D CT slices via contrastive learning. The pre-trained CNN backbone is then integrated into a CNN-LSTM […]

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arXiv:2601.20892v1 Announce Type: new Abstract: Developing new metal hydrides is a critical step toward efficient hydrogen storage in carbon-neutral energy systems. However, existing materials databases, such as the Materials Project, contain a limited number of well-characterized hydrides, which constrains the discovery of optimal candidates. This work presents a framework that integrates causal discovery with a lightweight generative machine learning model to generate novel metal hydride candidates that may not exist in current databases. Using a dataset of 450 […]

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Contextual Reinforcement Learning (CRL) tackles the problem of solving a set of related Contextual Markov Decision Processes (CMDPs) that vary across different context variables. Traditional approaches–independent training and multi-task learning–struggle with either excessive computational costs or negative transfer. A recently proposed multi-policy approach, Model-Based Transfer Learning (MBTL), has demonstrated effectiveness by strategically selecting a few tasks to train and zero-shot transfer. However, CMDPs encompass a wide range of problems, exhibiting structural properties that vary from problem to problem. […]

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arXiv:2601.16412v1 Announce Type: new Abstract: The study of textit{regret minimization in fixed-price bilateral trade} has received considerable attention in recent research. Previous works [CCC+24a, CCC+24b, AFF24, BCCF24, CJLZ25, LCM25a, GDFS25] have acquired a thorough understanding of the problem, except for determining the tight regret bound for GBB semi-feedback fixed-price mechanisms under adversarial values. In this paper, we resolve this open question by devising an $widetilde{O}(T^{2 / 3})$-regret mechanism, matching the $Omega(T^{2 / 3})$ lower bound from [CJLZ25] up […]

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