Hongtu Zhu

Fitting Nonlinear Ordinary Differential Equation Models with Random Effects and Unknown Initial Conditions Using the Stochastic Approximation Expectation–Maximization (SAEM) Algorithm

2020 · UNC Libraries

The past decade has evidenced the increased prevalence of irregularly spaced longitudinal data in social sciences. Clearly lacking, however, are modeling tools that allow researchers to fit dynamic models to irregularly spaced data, particularly data …

Leveraging Brain Modularity Prior for Interpretable Representation Learning of fMRI

2024 · IEEE Transactions on Biomedical Engineering

Resting-state functional magnetic resonance imaging (rs-fMRI) can reflect spontaneous neural activities in the brain and is widely used for brain disorder analysis. Previous studies focus on extracting fMRI representations using machine/deep learning methods, but these …

Enhancing Missing Data Imputation through Combined Bipartite Graph and Complete Directed Graph

2024 · arXiv (Cornell University)

In this paper, we aim to address a significant challenge in the field of missing data imputation: identifying and leveraging the interdependencies among features to enhance missing data imputation for tabular data. We introduce a …

MMedAgent-RL: Optimizing Multi-Agent Collaboration for Multimodal Medical Reasoning

2025 · arXiv (Cornell University)

Medical Large Vision-Language Models (Med-LVLMs) have shown strong potential in multimodal diagnostic tasks. However, existing single-agent models struggle to generalize across diverse medical specialties, limiting their performance. Recent efforts introduce multi-agent collaboration frameworks inspired by …