YufeiMa

Computer engineer. Web interfaces, applied ML, data pipelines, hardware-adjacent systems. San Diego, CA.

FocusWeb / ML / data / systems
EducationB.S. Computer Engineering
RecentPostmaster tracking platform
Based inSan Diego, CA

Projects

Postmaster

Repo ↗

End-to-end tracking platform that unifies USPS, UPS, and FedEx behind one API and a power-user web dashboard.

  • Designed and shipped a typed REST API on Cloudflare Workers that normalizes three carriers' tracking responses behind a single endpoint with consistent status, ETA, and event schema.
  • Engineered the full request pipeline: OAuth client-credential auth per carrier, key-value caching with status-aware TTLs, per-IP rate limiting, and structured error handling.
  • Hardened browser access with Cloudflare Turnstile attestation and origin-locked CORS; gated server-to-server calls with bearer auth.
  • Built the companion dashboard with batched lookups, client-side carrier auto-detection, inline event timelines, and CSV export, deployed globally on Cloudflare Pages.
TypeScript / Cloudflare Workers / Pages / KV / OAuth / Turnstile

Transformer-Based Music Generation

Repo ↗

From-scratch PyTorch transformer that produces coherent multi-track symbolic music without melody prompts.

  • Trained an unconditional symbolic music transformer on the POP909 dataset, applying segmented tokenization to capture phrase-level musical structure across multiple instrument tracks.
  • Built a CUDA-accelerated inference loop with configurable temperature and top-k sampling, surfacing the trade-off between conservative continuations and more exploratory outputs.
  • Fine-tuned a pretrained checkpoint with a custom tokenizer and 200-token context windows, balancing training throughput against musical coherence over longer horizons.
  • Adapted a conditional harmonization framework to the unconditional setting and benchmarked the resulting outputs against the reference distribution.
Generated output sample0:00 / 0:00
PyTorch / CUDA / POP909 / Hugging Face / BPE

Kendo Training Analysis Server

Repo ↗

Dual-sensor IMU pipeline that grades kendo technique on form, force, and exertion in real time.

  • Led the backend: a Flask service on Raspberry Pi that ingests time-series IMU and heart-rate data from a Galaxy Watch and a paired shinai sensor, persists sessions to SQLite, and serves a dashboard for review.
  • Designed strike-detection and form-scoring algorithms in NumPy — peak detection on accelerometer magnitude with 200ms refractory windowing, plus straightness and consistency scores derived from trajectory variance and waveform correlation.
  • Modeled strike kinematics from angular velocity (tip speed v = ω·r) to derive kinetic energy and impact force at the sword tip, then translated raw metrics into actionable training feedback (Effort, Control, Heart).
  • Owned the cross-disciplinary integration across REST APIs, embedded sensor sampling, CAD-printed mount hardware, and a small admin endpoint for backfilling new metrics across historical sessions.
Python / Flask / SQLite / NumPy / WearOS / Raspberry Pi

Experience

Tesla
Advisor
Aug 2025 - Dec 2025
San Diego, CA

Frontline diagnostic and customer-facing role on production EV hardware and software, working across Toolbox 3, firmware, and live customer support.

  • Diagnosed and resolved hardware-software faults on 25+ vehicles using Toolbox 3, comparing across firmware versions to isolate regressions and coordinating firmware reflashes and module replacements when service-tier fixes were insufficient.
  • Filed escalations that engineering acted on, including a same-day fix to a post-launch website with incorrect product information and a confirmed autopilot issue routed to the responsible team for resolution.
  • Supported a multilingual customer base in English, Mandarin, and Cantonese — walking customers through OTA update flows, autopilot and FSD behavior and limitations, mobile-app and account issues, and routing edge cases to the correct internal team when out of scope.
  • Trained incoming advisors on the diagnostic suite and core service workflows; maintained 99.7%+ customer satisfaction across the engagement.
Lex Software LLC
Backend Software Developer
Feb 2021 - May 2021
Remote

Owned end-to-end backend features for the community tooling behind a paid (~$40/mo) members-only platform with roughly 1,000 active subscribers.

  • Built moderation, onboarding, role assignment, scheduled-announcement, and post-management automations on Node.js against the Discord API, including channel archiving and data-scraping pipelines for writeup generation.
  • Designed and shipped REST endpoints in Node.js that served as the system of record for bot state and configuration, with the bot acting as a client against the API.
  • Owned features end-to-end: API design, implementation, containerized deploy, and post-deploy monitoring through Grafana and Sentry, with CI via GitHub Actions and integration testing via Postman.

Skills

Languages
PythonTypeScriptJavaScriptJavaCC++SQL
Frameworks
ReactNext.jsNode.jsExpressFastAPIFlaskVitePlaywright
Data + ML
PyTorchCUDAHugging FacePandasNumPyscikit-learn
Infra + Cloud
Cloudflare WorkersCloudflare PagesCloudflare KVAWSGCPDockerDocker ComposeGitHub ActionsGrafanaSentry
Databases + Auth
PostgreSQLMySQLSQLiteRedisOAuth 2.0JWTGitBashPostman
Hardware + Signals
IMU signal processingEmbedded sensorsRaspberry PiWearOSCAD3D printing