Kryshchenko, Alona
Quantile-Based Randomized Kaczmarz for Corrupted Tensor Linear Systems
Castillo, Alejandra, Haddock, Jamie, Hartsock, Iryna, Hoyos, Paulina, Kassab, Lara, Kryshchenko, Alona, Larripa, Kamila, Needell, Deanna, Suryanarayanan, Shambhavi, Djima, Karamatou Yacoubou
The reconstruction of tensor-valued signals from corrupted measurements, known as tensor regression, has become essential in many multi-modal applications such as hyperspectral image reconstruction and medical imaging. In this work, we address the tensor linear system problem $\mathcal{A} \mathcal{X}=\mathcal{B}$, where $\mathcal{A}$ is a measurement operator, $\mathcal{X}$ is the unknown tensor-valued signal, and $\mathcal{B}$ contains the measurements, possibly corrupted by arbitrary errors. Such corruption is common in large-scale tensor data, where transmission, sensory, or storage errors are rare per instance but likely over the entire dataset and may be arbitrarily large in magnitude. We extend the Kaczmarz method, a popular iterative algorithm for solving large linear systems, to develop a Quantile Tensor Randomized Kaczmarz (QTRK) method robust to large, sparse corruptions in the observations $\mathcal{B}$. This approach combines the tensor Kaczmarz framework with quantile-based statistics, allowing it to mitigate adversarial corruptions and improve convergence reliability. We also propose and discuss the Masked Quantile Randomized Kaczmarz (mQTRK) variant, which selectively applies partial updates to handle corruptions further. We present convergence guarantees, discuss the advantages and disadvantages of our approaches, and demonstrate the effectiveness of our methods through experiments, including an application for video deblurring.
A non-parametric optimal design algorithm for population pharmacokinetics
Hovd, Markus, Kryshchenko, Alona, Neely, Michael N., Otalvaro, Julian, Schumitzky, Alan, Yamada, Walter M.
This paper introduces a non-parametric estimation algorithm designed to effectively estimate the joint distribution of model parameters with application to population pharmacokinetics. Our research group has previously developed the non-parametric adaptive grid (NPAG) algorithm, which while accurate, explores parameter space using an ad-hoc method to suggest new support points. In contrast, the non-parametric optimal design (NPOD) algorithm uses a gradient approach to suggest new support points, which reduces the amount of time spent evaluating non-relevant points and by this the overall number of cycles required to reach convergence. In this paper, we demonstrate that the NPOD algorithm achieves similar solutions to NPAG across two datasets, while being significantly more efficient in both the number of cycles required and overall runtime. Given the importance of developing robust and efficient algorithms for determining drug doses quickly in pharmacokinetics, the NPOD algorithm represents a valuable advancement in non-parametric modeling. Further analysis is needed to determine which algorithm performs better under specific conditions.
COVID-19 Literature Topic-Based Search via Hierarchical NMF
Grotheer, Rachel, Huang, Yihuan, Li, Pengyu, Rebrova, Elizaveta, Needell, Deanna, Huang, Longxiu, Kryshchenko, Alona, Li, Xia, Ha, Kyung, Kryshchenko, Oleksandr
The appearance of the novel SARS-CoV-2 virus on the global scale has generated demand for rapid 1.1 Contributions research into the virus and the disease it causes, Our methods help make sense of a vast and rapidly COVID-19. However, the literature about coronaviruses growing body of COVID-19 related literature. The such as SARS-CoV-2 is vast and difficult main contributions of this paper are as follows: to sift through. This paper describes an attempt to organize existing literature on coronaviruses, - A diverse dataset of COVID-19 related scientific other pandemics, and early research on the current literature is compiled, consisting of COVID-19 outbreak in response to the call to articles with full-text available drawn from action issued by the White House Office of Science several online collections.