Ahmad A. Rushdi — Projects

High-d sampling & visualization

A library of high-dimensional test functions for optimization, uncertainty quantification, and numerical integration problems.

Model evaluation & UQ for AI/ML

Quantifying uncertainty in AI/ML predictive estimates, decomposing it into aleatoric and epistemic components, and using it to guide active learning. Applications across vision, image classification, regression, and time-series.

Vision. Uncertainty in object detection, segmentation, and image generation/captioning workflows.

DALL·E 3 generation — Text-to-image generation with DALL·E 3 (prompt: "A nature reserve with giraffe, elephant, zebra, lion, faceted style.")

YOLO detection — Object detection with YOLOv3 (COCO).

SAM segmentation — Image segmentation using Meta's Segment Anything (SAM).

BLIP captioning — Image captioning with BLIP (via Hugging Face inference API).

Image classification. Accuracy & uncertainty impact of rotation and AWGN on NN classifiers (MNIST / CIFAR).

MNIST under rotation.

MNIST under additive Gaussian noise.

1-d regression. Uncertainty bands with deep ensembles, MC dropout, and conformal prediction over limited noisy observations.

Uncertainty bands across methods.

Voronoi Piecewise Surrogate (VPS) models

Leveraging Voronoi diagrams and Delaunay graphs for global surrogate modeling in high-dimensional UQ and adaptive sampling under limited sample budgets (multifidelity / costly / high-stakes simulations).

VPS neighbors — Finding significant Voronoi neighbors in high dimension. paper

VPS surrogate — A global high-d surrogate stitching local patches in Voronoi cells. paper

gradients — Gradient samples for local active subspaces.

POF darts — Adaptive sampling for probability-of-failure estimation. paper

Meshing & mesh tuning

Creating and tuning 2-d / 3-d meshes with guaranteed quality properties.

VoroCrust: unclipped Voronoi mesh conforming to a high-quality surface mesh. paper

All-quad mesh — Robust all-quad meshing of domains with connected regions, with angle & edge-length guarantees. paper

Fourier & signal processing in bio / bioinformatics

Feature extraction (e.g., period-3 in DNA), object localization (e.g., echoes in ultrasound), and spectral analysis of high-d sampling techniques via Nd-FFT.

persistence spectrum — Persistence spectrum: a narrowband interference signal embedded in broadband.

Digital notch filtering to detect wideband ultrasound contrast echoes in blood.

Spoke-darts spectrum — Fourier spectrum of high-d sample patterns. paper

From computational methods to engineering applications

Extending mesh-tuning methods (e.g., non-obtuse triangulation, paper) to model fiber-reinforced polymers for elastic & failure simulations; and ML for collision detection and motion planning.

fiber simulation — Cross-section of a fiber micrograph and model at peak load; simulated tensile response of different packings. paper

Collision detection phase model.