Research & Writing

2026

False-colour comparison of HSC, HST and NEO galaxy imagery

Photometric Super-Resolution for Improving Galaxy Morphological Measurements using Conditional Generative Adversarial Networks

Samuel Kahn, Ryan Hausen, Hubert Bretonnière, Nicole E. Drakos, Brant E. Robertson

arXiv:2604.20195 (2026)

Morphological parameter estimation from astronomical images is limited by seeing, pixel scale, and depth. NEO is a conditional GAN: a U-Net generator with a super-resolution stage, paired with a PatchGAN discriminator, trained on ~1.5M paired HSC/HST cutouts in the COSMOS field. It reduces effective-radius bias from 0.72 ± 0.18 to 0.04 ± 0.30 and FWHM bias from 0.82 ± 0.05 to −0.02 ± 0.06, generalises to fields never seen during training, and reproduces the HST empirical PSF including its diffraction spikes. Built for LSST-era surveys in combination with HST, JWST, and Roman.

Schematic of incoming solar and reflected radiation across Earth's hemispheres

Towards a theory for Earth's albedo stability and hemispheric symmetry in the 21st Century

Daniel R. Feldman, Jake J. Gristey, Maria Z. Hakuba, Doug Hellinger, Samuel Kahn

Communications Earth & Environment (Nature Portfolio), 21 July 2026 · Open access

Understanding of top-of-atmosphere albedo stability and hemispheric symmetry remains largely phenomenological, producing diverging 21st-century estimates. We set out a framework for hypothesis testing and theory development, examine two competing hypotheses (that albedo is constrained by invariant Earth system properties, or is maintained by cloud buffering) and argue for a supporting role for AI methods that express the non-linear processes underlying these phenomena. Response to and relaxation from stratovolcanic eruptions offers a route to falsification.

Patents

Approaches to Predicting the Impact of Marketing Campaigns with Artificial Intelligence and Computer Programs for Implementing the Same

Samuel Kahn

U.S. Patent application 110565.8005.US01

Causal-inference methodology for isolating the true effect of a marketing campaign on a business metric in the presence of trend, seasonality, holidays, and latent confounders.

Press

Making Sense of the Early Universe: How AI and GPUs are helping astronomers work through unprecedented volumes of cosmic data

NVIDIA Blog, April 2026, featuring the NEO super-resolution work

Theses

Halo mass–concentration relation across redshifts

The Shape of Dark Matter Halos in a ΛCDM Cosmology

Samuel Kahn · Advisor: Joel R. Primack

Senior thesis, B.S. Physics, University of California, Santa Cruz, 2013

Measurement of dark matter halo concentration and triaxial shape in the Bolshoi and MultiDark N-body simulations, comparing shape estimators across redshift and testing how the relaxation criteria (offset parameter and virial ratio) affect the recovered mass–concentration relation.

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Writing

Diagram of a Thompson-sampling bandit allocating research agents under a code-computed verifiable reward

Verifiable Rewards for Predicting Multidistrict Litigation

A daily agentic discovery loop: a Thompson-sampling bandit allocates frontier research agents across search strategies under a reward computed in code, feeding a discrete-time hazard model of MDL consolidation at 0.90 held-out AUC.

banditsverifiable rewardssurvival model
Albedo climate network with hubs concentrated in the tropical Pacific

Agentic Discovery for Science

An autonomous AI scientist that ran 19 cycles and 49 analyses across 12 methodologies on 25 years of CERES satellite data, gated by a mandatory adversarial self-check, shuffle, confound, and robustness tests, before any result was recorded. Found that ENSO mediates hemispheric albedo coupling, and that cloud→albedo causality is unidirectional. Reported one of its three hypotheses as inconclusive.

agentsMCTScausal inference
GRPO training curves comparing reward and reasoning length across initializations

What GRPO Actually Optimizes

I treated a supervised label as an RLVR verifier and ran six GRPO configurations on a production risk classifier. Every variant landed on one ROC curve, and the labels drew it.

RLVRGRPOfine-tuning
RiskWise platform architecture diagram

RiskWise for the Era of Hyper-Automation

Why we built RiskWise: a platform that scales and automates risk analytics for the age of agents, and the emergent structure of risk it uncovers.

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Risk harness architecture diagram

The Agent Risk Harness

An agent is only as useful as the context it can assemble, the tools it can invoke, and the constraints that govern how it acts. What it takes to turn a model into a system.

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Win rate comparison chart

Improving Forecasting Models with Large Language Models

Augur, our LLM-guided covariate search. 15.6% average MAPE reduction, 13× faster, with logical validation of predictors.

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Coca-Cola composite risk index with driver-level components over five years

Seeing Risk Clearly: Moving Past Emotion to Measure Risk Exposure

Why sentiment is a poor proxy for exposure, and what an event-linked risk index looks like instead.

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Entity-level risk attribution accuracy: RiskWise-4B ahead of GPT-4o and GPT-4o-mini

Whispers of Latent Reasoning

A 4B thinking-tuned model beats GPT-5.2 on entity-level risk attribution, and keeps the gains even with chain-of-thought suppressed.

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Frontier model versus index comparison

RiskWise and Frontier AI: Rethinking How Emerging Risk Is Measured

Frontier models generate risk indices quickly, but reliable measurement needs transparent, event-linked signals. A head-to-head.

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Benchmark comparison chart

Surpassing Frontier AI for CPG & Retail

Dynamic hierarchical product categorization: a domain-tuned system beating OpenAI and Anthropic, at 100–1,000× human speed.

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Kernel density plot of MMR scores

Cold Start & Tuning for Retrieval Augmented Generation

How to tune a RAG system when you have no labelled data yet: chunking, retrieval parameters, and the MMR diversity trade-off.

ragretrieval
Causal impact of a marketing campaign

Predicting the Impact of Marketing Campaigns with AI

Year-over-year comparison is the wrong tool when the data-generating process isn't constant. Building a counterfactual instead. (Basis for a US patent application.)

causaltime series
Four considerations for CPG AI adoption

The AI-Augmented CPG, Part 1: What to Think About When Adopting AI

Four things to settle before expanding investment in generative AI: data sourcing, security, model selection, and evaluation.

strategydeployment
Predicted versus observed max power point time series

Recurrent networks for microgrid power forecasting

Predicting solar array max power point 10–60 minutes ahead at the NASA Ames Renewable Energy Testbed. Built the full pipeline: sensor integration on a Raspberry Pi, a MySQL schema and cron ingestion at five-minute resolution, then recurrent network models over the resulting series. Chart shows predicted (blue) against observed (red) at a ten-minute horizon.

RNNtime seriesenergy