Fatim Majumder | Applied Mathematics / Machine Learning PhD Applicant

Scientific computing, optimization, inference, and reliable ML systems.

Incoming Columbia M.S. in Applied Mathematics, Fall 2026. Emory B.S. in Computer Science and Mathematics, expected May 2026.

I work on reliable empirical ML, scientific computing infrastructure, optimization, statistical model comparison, uncertainty-aware decision-making, and AI for science.

Guiding Thesis

Modern ML systems should be treated as scientific instruments: calibrated, auditable, stress-tested, falsifiable, and reproducible.

  • Scientific Computing
  • Optimization
  • Inference
  • Statistical Learning
  • AI for Science
  • Reliable Intelligent Systems
  • 3.98 /4.00 cumulative GPA; 4.00 mathematics and 4.00 computer science
  • Columbia M.S. Applied Mathematics, incoming Fall 2026
  • 52,000+ controlled LLM evaluation jobs/month at Arthur AI
  • 6.4B+ weekly product events validated at Fullstory
  • 30+ member quantitative research organization led at Algory Capital
  • 1,200+ biomedical ML experimental runs supported

About / Research Profile

Research Profile

I am an applied mathematics and machine learning researcher building reproducible computational systems for model evaluation, scientific inference, and uncertainty-aware decision-making.

I turn informal empirical ML questions into controlled numerical experiments with explicit data-generating assumptions, artifact provenance, calibrated uncertainty, numerical stability checks, and statistically valid comparisons.

My research direction spans reliable AI for science, robust optimization, uncertainty quantification, graph-structured inference, differentiable simulation, and evaluation methods for foundation models.

Education

Applied mathematics preparation for doctoral research.

Columbia University | New York, NY

M.S. in Applied Mathematics

Incoming Fall 2026.

Planned focus: numerical analysis, scientific computing, stochastic processes, optimization, inverse problems, probabilistic modeling, statistical inference, and mathematical machine learning.

Emory University | Atlanta, GA

B.S. in Computer Science and Mathematics

Expected May 2026. GPA: 3.98/4.00 cumulative; 4.00 mathematics; 4.00 computer science.

Analysis

  • Real Analysis I-II
  • Multivariable Calculus
  • Differential Equations
  • Partial Differential Equations

Algebra

  • Abstract Algebra I-II
  • Linear Algebra
  • Foundations of Mathematics
  • Combinatorics

Numerical / Scientific Computing

  • Numerical Analysis
  • Numerical Linear Algebra
  • Iterative Methods

Probability / Statistics

  • Probability
  • Stochastic Processes
  • Mathematical Statistics I-II
  • Statistical Learning

Optimization

  • Numerical Optimization
  • Convex Optimization

CS / ML / AI

  • Algorithms
  • Theory of Computing
  • Machine Learning
  • Artificial Intelligence
  • Deep Learning on Graphs
  • Data Mining
  • AI for Science Reading Seminar

Research Interests

Four research directions.

Mathematical Machine Learning

Statistical learning theory, calibration, conformal prediction, robustness, model selection, representation learning, graph learning, distribution shift, and benchmark validity.

Optimization and Numerical Computation

Stochastic approximation, adaptive first-order methods, mirror descent, momentum, preconditioning, constrained optimization, inverse problems, and PDE-constrained learning.

Scientific Computing and AI for Science

Numerical linear algebra, Krylov methods, state-space inference, differentiable simulation, surrogate modeling, uncertainty quantification, active experimentation, and structure-aware neural systems.

Reliable AI Systems

LLM evaluation, tool-use and retrieval benchmarks, agent reliability, artifact lineage, dataset/version control, inference orchestration, auditability, observability, and failure-mode analysis.

Experience

Research engineering as empirical ML discipline.

These roles are presented for the methods they required: reproducible experiments, statistical validation, lineage-aware infrastructure, and careful model comparison.

Arthur AI | May 2025 - Aug. 2025

Machine Learning Research Engineering Intern

  • Built an experiment-control layer for LLM evaluation with typed runs over dataset snapshot, prompt graph, model artifact, tokenizer revision, sampling policy, inference backend, judge rubric, scorer, postprocessor, aggregation rule, and environment hash.
  • Scaled benchmark execution to 52,000+ controlled evaluation jobs/month while raising exact rerun reproducibility from 71.4% to 99.98%.
  • Reduced median experiment turnaround from 9.6 hours to 54 minutes with asynchronous scheduling, adaptive batching, retry semantics, circuit breakers, and cost-aware queue priorities.
  • Implemented paired bootstrap intervals, stratified randomization tests, multiple-comparison correction, per-slice uncertainty bands, effect-size reporting, judge reliability diagnostics, and contamination detection.
  • Improved judge agreement from kappa = 0.43 to 0.76 and identified prompt-template leakage / near duplicates that inflated a reasoning suite by 5.8 absolute points.

Fullstory | May 2024 - Aug. 2024

Software Engineering Intern

  • Built analytics validation infrastructure for 6.4B+ weekly product events, covering schema evolution, event freshness, transformation replay, metric discontinuities, cardinality explosions, join drift, null spikes, and deploy-correlated anomalies.
  • Reframed monitoring as online statistical inference over a changing data-generating process.
  • Implemented robust z-scores, seasonal baselines, KS drift tests, population-stability indexes, entropy checks, foreign-key integrity tests, and lineage-neighbor correlation checks.
  • Improved alert precision from 61% to 97%, reduced false-positive pages by 82%, lowered median time-to-detection from 3.7 hours to 6 minutes, and reduced median debugging time from 2.8 hours to 19 minutes.

Algory Capital, Emory University | Sept. 2023 - Present

Head of Research

  • Led research infrastructure and analyst development for a 30+ member quantitative research organization.
  • Architected a point-in-time research platform spanning ingestion, universe construction, feature engineering, factor testing, walk-forward modeling, portfolio construction, transaction-cost simulation, exposure control, and attribution.
  • Increased reproducible research throughput by 8.4x and produced 18 reviewed research memos and 11 reproducible project repositories.
  • Added leakage-aware evaluation, portfolio optimization, and statistical validation layers for multiple testing, White-style reality checks, deflated Sharpe, false discovery control, unstable correlation warnings, regime sensitivity, and backtest-overfitting alarms.

Georgia Tech / Emory University | Sept. 2022 - Jan. 2024

Research Assistant

  • Developed biomedical ML pipelines supporting 1,200+ controlled experimental runs across cohort definitions, preprocessing variants, imaging features, clinical covariates, fusion strategies, calibration procedures, subgroup analyses, and decision thresholds.
  • Rebuilt cohort construction around patient-level independence, temporal separation, site-aware validation, feature availability, and label-proxy audits.
  • Improved clinically meaningful held-out AUROC from 0.69 to 0.86 and expected calibration error from 0.18 to 0.045 after leakage removal, standardized preprocessing, model-family sweeps, and systematic ablations.
  • Implemented bootstrap CIs, DeLong-style AUROC comparisons, AUPRC, sensitivity/specificity, decision-curve analysis, subgroup calibration, missingness analysis, and error taxonomy.

Selected Projects

Computational research projects with visible experimental assumptions.

The project archive emphasizes benchmark design, leakage-aware validation, robustness testing, state-space simulation, and reproducible empirical workflows.

Generative audio robustness

RE-AMP

Full-stack benchmark platform for generative audio models with 18,000+ controlled robustness runs, 82 perturbation operators, 9 evaluator families, deterministic manifests, and signal-level, perceptual, and model-based metrics.

Read case study

Graph learning

Traffic Collision Risk Modeling

Heterogeneous spatiotemporal graph prediction over 1.1M+ collision records and road-network topology, improving hotspot-ranking AUROC by 23.4 points and top-decile recall by 31% with leakage-aware validation.

Read case study

State-space estimation

Robust Kalman Filtering

Modular localization simulation comparing standard Kalman filtering with robust variants under sensor dropout, delayed observations, outlier regimes, correlated process noise, and measurement misspecification; median error fell 49%.

Read case study

Quantitative research

Quant Research Lab

Public-facing factor research and backtesting demo with point-in-time ingestion, signal construction, portfolio formation, evaluation, transaction-cost modeling, benchmark comparison, attribution, and reproducible tearsheets.

Read case study

Notes / Writing

Mathematical preparation made visible.

These notes emphasize derivation, geometric intuition, computational experiments, and failure cases.

in progress

Stochastic Optimization Notes

Mirror descent, momentum, stochastic approximation, and control-oriented views of optimization.

draft

Numerical Linear Algebra Notes

Spectral structure, conditioning, approximation, and the numerical behavior of ML computations.

draft

Graph Learning Notes

Road networks, spectral graph structure, message passing, retrieval, and representation learning.

draft

Diffusion Models and ML Foundations

Generative modeling, stochastic processes, denoising objectives, and computational failure modes.

outline

Gaussian Processes with Derivative Matching

Probabilistic modeling, derivative observations, covariance structure, and smoothness assumptions.

outline

Robust Kalman Filtering

State-space estimation under misspecification, delayed observations, outliers, and dropout.

Honors / Leadership

Academic and technical leadership markers.

Technical Skills

Applied math, ML, research infrastructure, and reliable systems.

Languages

Python, C++, C, SQL, TypeScript, JavaScript, Java, Bash, MATLAB, LaTeX

ML / AI

PyTorch, JAX, PyTorch Geometric, scikit-learn, XGBoost, statsmodels, Ray, LLM evaluation, graph ML, multimodal ML, transformer inference, retrieval evaluation, robustness testing, ablation studies, uncertainty estimation

Applied Math / Scientific Computing

Numerical linear algebra, Krylov methods, preconditioning, convex/numerical optimization, stochastic approximation, state-space models, Kalman filtering, Monte Carlo simulation, Bayesian inference, statistical learning, spectral methods, graph algorithms

Data / Research Infrastructure

PostgreSQL, MySQL, DuckDB, Redis, Kafka, Airflow, dbt, ETL/ELT, dataset versioning, artifact lineage, experiment tracking, reproducible replay, structured logging

Backend / Systems

FastAPI, Docker, Kubernetes, AWS, Linux, Git, GitHub Actions, CI/CD, distributed queues, async orchestration, caching, batching, observability, profiling

Evaluation / Reliability

Benchmark design, metric validation, regression detection, prompt/dataset lineage, statistical comparison, confidence intervals, run-diff tooling, audit logs, failure analysis, incident triage, model-risk documentation

Contact

Research conversations and collaboration.

I am especially interested in research mentorship and projects at the intersection of applied mathematics, mathematical ML, optimization, scientific computing, AI for science, statistical evaluation, and reliable AI systems.