Research

Five threads run through my work. Each one is a general problem about learning across institutions and predicting when, worked out on hospital data. They overlap more than the list suggests.

Federated learning across institutions

Institutions that cannot hand each other their data still need to learn from each other, so the model travels to the data instead of the other way around. Each site trains on what it holds and sends back only what the model learned, never the records. The hard part is that sites are not interchangeable: their populations, their record-keeping, and how well they follow up all differ, so naive averaging quietly buries the ones that matter. Hospitals are the case I work on. Banks and insurers sit under the same constraint for their own reasons.

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Survival analysis and time-to-event

Survival analysis asks not whether something will happen but when, and it has to handle the cases whose outcome nobody has seen yet because they are still running or stopped being observed. That is usually the question people need answered: when will this patient get worse, when will this borrower default. Insurance pricing and equipment maintenance run on the same question. My own work is on clinical data, with Cox proportional hazards models and deep survival networks trained across many centers at once.

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Trust and privacy between institutions

To know whether another institution is helping your model, you would like to inspect what they sent. That is exactly the thing federated learning exists to prevent, and any federation of near rivals runs into it. My work builds reputation between sites from privacy-protected versions of their updates: enough signal to tell whether a peer helped, not enough to learn anything about a patient. Hospitals are where I measured it.

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Decentralized and edge systems

A central server is a convenient assumption and a bad single point of failure, and plenty of networks have nobody that everyone would trust to run one. I study peer-to-peer training where the network of who talks to whom is sparse, keeps changing, and has to earn its connections, along with what it takes to run these models on small hardware at the edge of a clinic rather than in a data center.

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Language models and agent systems

Most agent work assumes somebody else is paying for the compute: a large model behind an API, context to spare, a network that is always there. Take those away and most of what we have built stops working. That gap is the interesting part. The setting I know best is clinical, where the work is mostly text and language models are finally good enough to be useful on it, as long as the reasoning can be shown and checked. I work on fine-tuning, retrieval, and agent tooling for clinical decision support.

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What the numbers look like

Every figure below comes from the paper named above it.

HARMONY: Hybrid Aggregation and Reputation Mechanism for Cooperative Federated Survival Analysis

IEEE Journal of Biomedical and Health Informatics (JBHI) · 2026 · accepted September 1, 2026

Reported results for HARMONY: Hybrid Aggregation and Reputation Mechanism for Cooperative Federated Survival Analysis
MeasureValueComparisonSetting
C-index under 30% adversarial clients0.673FedAvg 0.622, Krum 0.648, Median 0.634SEER, federated survival model with 30% adversarial clients
Round-to-round stabilityabout 35% lower C-index variance at 20% adversariesfor 12% extra communicationSEER
Best per-registry C-indexup to 0.819—per SEER registry
Time to penalize an adversarial client3 to 5 rounds—reputation mechanism response time
Statistical significance of improvementsp < 0.05, paired effect sizes Cohen's d_z about 1.6 to 2.4—HARMONY JBHI rebuttal and dissertation ch. 6
Federated round timeabout 120 to 180 ms per full round—wall-clock cost of one complete federated round

Adaptive Bayesian Partner Selection for Federated Clinical Centers

arXiv preprint · 2026 · preprint

Reported results for Adaptive Bayesian Partner Selection for Federated Clinical Centers
MeasureValueComparisonSetting
AUROC on in-hospital mortality0.758matches FedDyn at 0.09x the communication bandwidth of FedAvgMIMIC-IV v3.1, 230 federated centers, compared against 12 baselines
Seed variance0.010baseline 0.017run-to-run stability across random seeds
Intentional isolation of unhelpful centers41% of centers isolated at 0.16x bandwidth—MIMIC-IV federated setup

Evolving Sparse P2P Networks for Federated Survival Prediction with Adaptive Utility

IEEE/ACM Conference on Connected Health: Applications, Systems and Engineering Technologies (CHASE) 2026, Pittsburgh, PA, USA · 2026 · accepted August 2, 2026; presented August 2026

Reported results for Evolving Sparse P2P Networks for Federated Survival Prediction with Adaptive Utility
MeasureValueComparisonSetting
C-indexabout 0.795centralized training 0.785SEER, 13 registries, sparse peer-to-peer topology
Integrated Brier Scoreabout 0.153—SEER, 13 registries
Communication reductionmore than 95% less than FedAvg—sparse peer-to-peer topology; graph reorganizes within two epochs under drift

Addressing Data Heterogeneity in Federated Learning of Cox Proportional Hazards Models

IEEE International Conference on E-health Networking, Application & Services (Healthcom) 2024, Nara, Japan · 2024 · published

Reported results for Addressing Data Heterogeneity in Federated Learning of Cox Proportional Hazards Models
MeasureValueComparisonSetting
Convergenceproven linear convergence—feature-presence clustering of federated centers