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  • KAIST - Korea Advanced Institute of Science and Technology
  • South Korea
  • 08:29 (UTC +09:00)
  • LinkedIn in/aamirmalik-dr

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aamirmalik-dr/README.md

Aamir Malik

Data-Driven Materials Scientist (PhD, KAIST) working at the intersection of machine learning and the physical sciences. My work spans density-functional calculations, machine-learned interatomic potentials, molecular representation learning, deep learning for electron microscopy, active learning and uncertainty quantification, quantitative finance, generative models, and classical statistics.

Two habits run through everything here. I build the core machinery from scratch, periodic neighbor lists, message passing, backpropagation, attention, Gaussian-process posteriors, and I benchmark every learned method against a fair-tuned classical baseline. Each repository has an honest README, a reproducible demo that was actually run, and only real measured results, including the negative ones.

First-principles calculations and machine learning interatomic potentials

  • pd-hydrogen-diffusion-dft - Hydrogen diffusion in fcc palladium from CP-PAW density-functional calculations: a translation-invariant reaction coordinate, the octahedral-to-tetrahedral energy profile, and harmonic transition-state theory, with every input and protocol committed. The diffusion constant comes within a factor of seven of experiment, with its convergence limits stated plainly.
  • mlip-descriptor-potential - A Behler-Parrinello neural network potential from scratch in PyTorch: periodic neighbor lists, atom-centered symmetry functions, per-element networks, and autograd forces, benchmarked at matched budget against a tuned ridge model and a Morse pair potential with a leakage-safe group split.
  • graph-neural-forcefield - A SchNet-style message-passing potential on the same chemistry, benchmarked head to head against the descriptor network and the ridge baseline. The headline is data efficiency: it matches the linear baseline's full-data force accuracy with 102 of 882 training frames.
  • alloy-mlip-bench - The potentials deployed as ASE calculators and benchmarked against CHGNet and MACE-MP-0 small on equation of state, elastic constants, RDFs, thermal expansion, and vacancy formation. The compact distilled model nearly matches its teacher at 14.6x the MD speed.
  • forcefield-active-learning - Query-by-committee active learning for these potentials, against a random buyer at identical label budget. The honest headline is a measured negative: random selection wins on a well-mixed pool, while the same committee earns a 2.2x label saving on a redundancy-heavy one.

Molecular representation learning and generative modeling

  • graph-neural-networks-for-molecules - Message passing neural networks (MPNN and GCN) for molecular property prediction, written from scratch in PyTorch with no graph-learning framework, benchmarked on public MoleculeNet ESOL with a message-passing depth ablation.
  • molecular-property-prediction - A controlled comparison of three molecular representations for property prediction in PyTorch, a Morgan fingerprint MLP, a SMILES 1D-CNN, and a SMILES LSTM, trained on one shared codebase with RDKit-computed targets.
  • molecular-generative-models - A from-scratch SMILES GRU autoencoder and variational autoencoder in PyTorch with reparameterization and KL annealing, scored on the validity, uniqueness, and novelty of the molecules they generate.

Deep learning for electron microscopy imaging

  • stem-atom-finder - Atomic column detection in simulated HAADF-STEM images: a Laplacian-of-Gaussian detector versus a compact U-Net across a 2000x electron dose range, with sub-pixel refinement and an oracle-tuned baseline as the fairness control.
  • stem-denoising-restoration - Restoration of low-dose electron microscope images, scored by image fidelity and by downstream atom detection: variance-stabilized classical denoisers versus a residual U-Net trained supervised and as self-supervised Noise2Noise, with off-distribution checks.
  • stem-defect-segmentation - Pixel-level segmentation of simulated STEM into five defect classes with exact ground truth: a threshold-and-morphology baseline and a random-forest pixel classifier versus a multi-class U-Net, scored on per-class IoU, Dice, and boundary error.

Machine learning for diffraction and spectroscopy

  • diffraction-structure-classifier - Crystal-structure classification from simulated electron diffraction: a tuned classical baseline versus 1D radial-profile and 2D rotation-invariant polar-Fourier CNNs, with a shortcut control measuring how much accuracy is material identity rather than structure.
  • eels-spectrum-unmixing - Unsupervised decomposition of simulated STEM-EELS spectrum images into endmember spectra and abundance maps: PCA, NMF, and a from-scratch VCA versus a constrained linear-unmixing autoencoder, across dose, energy-drift, and spectral-overlap sweeps.
  • 4d-stem-orientation-mapping - Orientation and phase mapping from simulated 4D-STEM datacubes: template matching with sub-step refinement, a symmetry-aware CNN, and unsupervised grain clustering. The plainly reported negative result: fair-tuned template matching beats the CNN at every dose.

Active learning and uncertainty quantification

  • active-learning-microscopy - A simulation study of the autonomous-experiment loop, asking when a Gaussian-process-steered probe beats a competent space-filling scan against exact ground truth, built on a from-scratch GP with sequential posterior updates and measured failure regimes.
  • gaussian-process-flow-modeling - Gaussian-process regression reconstructing a divergence-free 2D velocity field from sparse noisy samples, with RK4 particle advection and a calibrated uncertainty map. The uncertainty-quantification counterpart to the active-learning study.

Computer vision: classification, generation, and adversarial robustness

  • image-classification-pytorch - A CIFAR-10 architecture study in PyTorch comparing an MLP, a plain CNN, and VGG-style and ResNet-style networks under one shared training budget, with a regularization ablation isolating what each technique contributes.
  • medical-image-classification - Chest X-ray pneumonia screening on public MedMNIST data, comparing a from-scratch CNN with a transfer-learning ResNet-18 and reporting accuracy, recall, and ROC-AUC. A teaching example, not a clinical tool.
  • gan-image-generation - A DCGAN in PyTorch generating handwritten-digit images from random noise, with a clean adversarial training loop, generator and discriminator loss curves, and sample grids tracking output quality over training.
  • adversarial-attacks - FGSM, iterative, and least-likely-class adversarial attacks on an MNIST image classifier in PyTorch, with robustness-versus-epsilon curves showing how accuracy degrades as the perturbation budget grows.

Sequence modeling and NLP

  • text-sentiment-lstm - A bidirectional LSTM sentiment classifier in PyTorch on public Rotten Tomatoes data, with a from-scratch tokenizer and vocabulary pipeline and optional pretrained GloVe embeddings in place of learned ones.
  • neural-machine-translation - A sequence-to-sequence translation model with Bahdanau attention, built from scratch in PyTorch and demonstrated on a date-normalization task with 100 percent exact-match accuracy and interpretable attention alignment maps.

Quantitative finance and time series

  • neural-option-pricing - Classical option-pricing engines from scratch (Black-Scholes, binomial, Crank-Nicolson, variance-reduced Monte Carlo, Heston), plus a neural pricing surrogate and a CVaR-trained deep hedging policy, benchmarked honestly on simulated markets against tuned classical baselines that close much of the neural gap.
  • financial-forecasting-benchmarks - A walk-forward benchmark of ML models against fair-tuned classical baselines for daily return and volatility forecasting on eight US ETFs over two decades. The defended null result: next-day returns are essentially unforecastable, and GARCH(1,1) beats LightGBM and an LSTM at volatility.
  • yield-curve-factor-analysis - PCA and NMF factor analysis of the US Treasury yield curve, recovering the classic level, slope, and curvature factors from public rates data, with a resilient, offline-capable data pipeline.
  • time-series-forecasting - Classical time-series forecasting end to end: STL decomposition into trend and seasonal components, ARIMA and SARIMAX models, and a walk-forward backtest reporting RMSE and MAPE.

Neural networks and classical ML from scratch

  • neural-network-from-scratch - A feedforward network in pure NumPy: backpropagation, SGD/Momentum/Adam, He and Xavier initialization, L2 and dropout, and numerical gradient checking as the correctness proof, demonstrated on a two-moons task.
  • classical-ml-from-scratch - Linear and logistic regression, k-nearest neighbors, a CART decision tree, Gaussian naive Bayes, a kernel SVM, k-means, PCA, and Gaussian-mixture EM in NumPy, each unit-tested against scikit-learn.

Statistical and probabilistic modeling

  • high-dimensional-genomics-ml - PCA, clustering, and cross-validated classification on the public Golub leukemia gene-expression set, plus differential expression with a from-scratch Benjamini-Hochberg FDR correction.
  • tabular-ml-pipeline - A reusable scikit-learn pipeline for messy tabular data: ColumnTransformer imputation and encoding, LASSO feature selection, and a tuned multi-model comparison, on the public UCI Adult dataset.
  • temporal-network-analysis - Per-phase structure and centrality trajectories in a time-varying network with networkx, validated on a synthetic role-planted graph, with an optional path to the public SNAP CollegeMsg dataset.
  • statistical-methods-in-r - A collection of statistical analyses in base R: hypothesis testing, ANOVA, regression, PCA and factor analysis, and from-scratch association-rule mining, fully reproducible with no external packages.

Skills and tools

  • Languages: Python, R
  • Frameworks and libraries: PyTorch, scikit-learn, NumPy, ASE, RDKit, statsmodels, networkx, pandas, Matplotlib
  • Simulation codes: CP-PAW (density-functional theory, projector augmented wave method)
  • Learned methods: message passing neural networks, interatomic potentials with autograd forces, U-Net segmentation, CNNs, LSTMs, sequence-to-sequence with attention, variational autoencoders, GANs
  • Statistical methods: Gaussian-process regression, active learning, PCA/NMF/VCA decompositions, ARIMA/SARIMAX and GARCH modeling, walk-forward evaluation with Diebold-Mariano tests and block bootstrap, multiple-testing control with Benjamini-Hochberg FDR

Contact

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  1. graph-neural-forcefield graph-neural-forcefield Public

    From-scratch SchNet-style message-passing neural network potential for BCC TiZrNb, benchmarked head to head against descriptor baselines at matched data and budget. Surrogate teacher labels (CHGNet…

    Jupyter Notebook

  2. alloy-mlip-bench alloy-mlip-bench Public

    MLIPs as ASE calculators, benchmarked on BCC TiZrNb properties: a distilled compact potential vs pretrained foundation potentials, accuracy vs speed

    Jupyter Notebook

  3. 4d-stem-orientation-mapping 4d-stem-orientation-mapping Public

    4D-STEM orientation and phase mapping on simulated polycrystals: kinematical simulator with exact ground truth, virtual imaging, template matching, symmetry-aware CNN, grain clustering, fixed-seed …

    Jupyter Notebook

  4. active-learning-microscopy active-learning-microscopy Public

    Gaussian-process active learning for autonomous microscopy, benchmarked against space-filling scans.

    Jupyter Notebook

  5. graph-neural-networks-for-molecules graph-neural-networks-for-molecules Public

    From-scratch message passing neural networks (MPNN, GCN) in PyTorch for molecular property prediction on ESOL.

    Python

  6. neural-option-pricing neural-option-pricing Public

    Classical option pricing and hedging engines plus a neural Heston surrogate and a CVaR-trained deep hedging policy, benchmarked honestly on simulated markets

    Jupyter Notebook