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Portfolio

Things I've built, and what each one taught me

Production security and defense work I can only describe in outline, research projects with the numbers attached, and side projects I built because something annoyed me. Sorted by how much I want you to read them.

Play the games

Projects

Personal2026

neural-cost

A framework-neutral Python library that tells you how fast a neural network should run, not just how fast it does — FLOPs, tensor traffic and a roofline model across PyTorch, JAX and TensorFlow.

JAX won 4 of 5 architectures on the M3 CPU, then 1 of 5 on its GPU
PythonPyTorchJAXTensorFlow
Capstone2021

Sign Language Interpretation System

Control any smart device with American Sign Language — hand tracking, a gesture classifier and grammar correction, wired together over a client-server link.

98.8% accuracy across 14 hand gestures
PythonTensorFlowMediaPipeC++
Research2025

Patient Care Portal Triage

An NLP pipeline that routes patient portal messages to the right team and surfaces relevant evidence-based research while they wait for a human.

Classifies sentence embeddings into care teams, then retrieves supporting research
PyTorchEmbeddingGemmaNLPInformation retrieval
Diagram of a delivery pipeline running from a commit, through verified build and policy stages, into a Kubernetes cluster, with a trust boundary drawn at every hand-off.
Professional2025 — present

Threat modeling a zero-trust deployment pipeline

A continuous deployment pipeline for configuration-as-code and infrastructure-as-code into Kubernetes, designed from its threat model outward so the release process does the security review.

Security review is a stage of the release, not a meeting before it
Threat modelingKubernetesHelmAzure
Diagram of three applications moving into a Kubernetes cluster on Azure, each running beside a service-mesh sidecar, with encrypted links between them.
Professional2025 — present

Moving three toolchain apps to Kubernetes on Azure

Three toolchain applications moved to Kubernetes on Azure, deployed one way with Helm and infrastructure-as-code, and secured with an Istio service mesh.

Live demo that helped secure the company's share of a $90M award
KubernetesAzureIstioHelm
Diagram of the software stack, from hardware and kernel up through the communication protocol and task scheduler to application tasks, beside a timing chart of three periodic tasks sharing one core without missing a deadline.
Professional2021 — present

A processor built from the ground up

Kernel, task scheduler and communication protocol written from nothing, in C and Ada, now in production and distributed globally.

In production. Globally distributed.
CAdaRTOSBare metal
Personal2023 — present

Bindersnap

GitHub for everyone who doesn't use GitHub — document management, review lifecycle, team collaboration, search and an in-browser editor.

Started because my wife complained about her company's policy platform
GoVueAWSSQL
Professional2023

A system library that runs anywhere

One portable C++ library targeting any RTOS or bare-metal system, packaged with Docker, Bazel and GitLab CI — cutting porting work by 4×.

4× fewer engineering hours spent on porting
C++BazelDockerGitLab CI
School2026

LaCam for Multi-Agent Path Finding

A from-scratch LaCam solver for CS440 — agents searching a space of joint configurations, each expanded by a constraint tree that rules out collisions and swaps.

Search over joint configurations, not per-agent paths — the whole trick of LaCam
PythonSearchMulti-agent systems
Personal2024
Playable

Wordlet

A word guessing game built in Flutter and compiled to the web — playable right here, no install, no account.

Play it in the browser in about two seconds
DartFlutterWeb
Personal2026

This website

A static site built with Astro, hosted free on GitHub Pages, designed so writing a post costs one markdown file and nothing else.

Zero JavaScript on most pages
AstroTypeScriptTailwindGitHub Pages

Archive

Coursework from undergrad

Where I learned the basics properly. Kept because the code and reports are still downloadable, not because they're the best thing here.

Let's connect

Want the version with more detail?

A lot of the best work is easier to explain out loud than in writing. Ask me about any of it.

Email me

Usually replies within a day or two · St. Louis, Missouri

ESC

Home

Main landing page & highlights

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Work

All engineering projects & case studies

Page

Writing

Technical notes & engineering articles

Page

Games

Browser games, several against real models

Page

About

Background, career timeline & skills

Page

Contact

Email, inquiries & consultation

Page

Copy Email Address

[email protected]

Action

Toggle Light / Dark Theme

Switch color theme

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Resume

Web page, with a PDF download

Read

Visit GitHub

github.com/davidgraymi

External

Visit LinkedIn

linkedin.com/in/david-gray-mi

External

Beat the bot

Tetris against the value network from my reinforcement-learning project. Same pieces, two minutes, most lines wins.

Game

Draw a digit

Draw 0–9 and watch a weighted KNN classifier find its nearest MNIST neighbours as you go.

Game

Is it poisonous?

A real mushroom from the UCI dataset. Make your call, then watch an ID3 decision tree make its own.

Game

Route the robots

Draw a warehouse, place robots and goals, and race a LaCAM multi-agent path-finding solver to the shortest plan.

Game

Daily Wordlet

One five-letter word a day, the same for everyone. Six guesses.

Game

Bot or human?

14 rounds. One line from a public-domain classic, one written by a language model. Spot the bot.

Game

Reaction test

Wait for the panel to light up amber, then hit it as fast as you can.

Game

Lost signal

The 404 page's dodge game. Packets rain down; steer the receiver out of the way.

Game

neural-cost

A framework-neutral Python library that tells you how fast a neural network should run, not just how fast it does — FLOPs, tensor traffic and a roofline model across PyTorch, JAX and TensorFlow.

Personal

Sign Language Interpretation System

Control any smart device with American Sign Language — hand tracking, a gesture classifier and grammar correction, wired together over a client-server link.

Capstone

Patient Care Portal Triage

An NLP pipeline that routes patient portal messages to the right team and surfaces relevant evidence-based research while they wait for a human.

Research

Threat modeling a zero-trust deployment pipeline

A continuous deployment pipeline for configuration-as-code and infrastructure-as-code into Kubernetes, designed from its threat model outward so the release process does the security review.

Professional

Moving three toolchain apps to Kubernetes on Azure

Three toolchain applications moved to Kubernetes on Azure, deployed one way with Helm and infrastructure-as-code, and secured with an Istio service mesh.

Professional

A processor built from the ground up

Kernel, task scheduler and communication protocol written from nothing, in C and Ada, now in production and distributed globally.

Professional

A system library that runs anywhere

One portable C++ library targeting any RTOS or bare-metal system, packaged with Docker, Bazel and GitLab CI — cutting porting work by 4×.

Professional

LaCam for Multi-Agent Path Finding

A from-scratch LaCam solver for CS440 — agents searching a space of joint configurations, each expanded by a constraint tree that rules out collisions and swaps.

School

Bindersnap

GitHub for everyone who doesn't use GitHub — document management, review lifecycle, team collaboration, search and an in-browser editor.

Personal

Wordlet

A word guessing game built in Flutter and compiled to the web — playable right here, no install, no account.

Personal

Reinforcement Learning applied to Tetris

An agent that learns to play Tetris — a genuinely fun excuse to get hands-on with reward shaping.

School

Handwritten digit recognition with weighted KNN

A KNN classifier for handwritten digits, plus a k-value optimizer that collapses repeated distance calculations into a single pass.

School

ID3 mushroom classification

A from-scratch ID3 decision tree that predicts whether a mushroom is edible or poisonous from its attributes.

School

Healthcare length-of-stay estimator

A data mining project predicting how long a patient will stay, from admission-time features.

School

This website

A static site built with Astro, hosted free on GitHub Pages, designed so writing a post costs one markdown file and nothing else.

Personal

An Unexpected Email, REPRO-SIGN, and 11 Citations on Google Scholar

Years after our college capstone, an out-of-the-blue email from European AI researchers wanting to reproduce our sign language paper sent me to Google Scholar, where we've been cited 11 times.

Post

Connecting the Dots: How a Sign Language Capstone Got Me Hooked on AI

Looking back at my senior capstone project at Missouri State — building a real-time American Sign Language smart home controller with MediaPipe, custom CNNs, and networking — and how it sparked my path in machine learning.

Post

GPU vs. CPU: Roofline Benchmarks on Apple Silicon MPS with neural-cost v0.2.0

The neural-cost v0.2.0 GPU benchmark moves from CPU roofline analysis to Apple Silicon's MPS GPU backend — measuring PyTorch and JAX across five architectures, four batch sizes, and both eager and compiled execution modes.

Post

PyTorch vs. JAX vs. TensorFlow: A Roofline Benchmark Across 5 Architectures

An empirical investigation comparing PyTorch 2.14, JAX 0.11, and TensorFlow across five model architectures and four batch sizes, measuring compiler speedups, kernel overheads, and hardware limits on Apple Silicon.

Post

neural-cost: Roofline Analysis Across PyTorch, JAX, and TensorFlow

A framework-neutral Python library that estimates a neural network's FLOPs and tensor traffic, measures its runtime, and uses a roofline model to tell you exactly where performance is being left on the table.

Post

I rebuilt this site so that publishing costs one file

The old site was a single 41,000-character index.html. Every change was archaeology. Here is what I replaced it with and why the constraint was maintenance, not design.

Post
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