SDE · MLE · Agent Engineering · New York

Hi, I'm Christina Jia. I build AI agents
that ship to production.

M.S. Computer Engineering @ Columbia, graduating Dec 2026. SWE intern at TikTok Trust & Safety this past summer, now Lead Data Engineering & ML Intern at DiyoWater; previously Johnson & Johnson and iQIYI. I make LLM agents, ML systems, and vision pipelines measurable, debuggable, and reliable.

Dec '26
Columbia MS CE
6
Internships & research
20+
Projects shipped
25+
Prod models operated
scroll
01 · Who I am

The last mile of AI is my favorite mile.

I'm a Computer Engineering master's student at Columbia University with six internships and research roles across TikTok, DiyoWater, Johnson & Johnson Medical, iQIYI, UAES, and SJTU. My sweet spot is the unglamorous last mile of AI: evaluation, reliability, and infrastructure, making agents measurable, debuggable, and safe to ship.

I've built LoRA fine-tuning fleets and TensorRT edge deployments, multi-agent daemons with five-layer memory systems, TLA+-verified distributed locks, and Go async task infrastructure for an LLM agent in production. I'm especially drawn to computer vision: detection on the edge, diffusion and LoRA, computational imaging, and 3D reconstruction. If it involves a model meeting the real world, I've probably debugged it at 2 a.m.

Off the clock I'm usually behind a camera, on a bouldering wall, mapping my travels into a hand-built interactive atlas, or drawing pixel worlds. I like building things on both sides of the art and engineering line.

Currently

  • Lead Data Engineering & ML Intern @ DiyoWater, part-time
  • Research in Prof. Zhou Yu's lab @ Columbia, evaluating conversational LLM agents
  • Graduating Dec 2026, open to 2027 SDE / MLE / CV roles
02 · Experience

Where I've shipped.

DiyoWater

Lead Data Engineering & ML Intern Jun 2026 · Present
  • Scaled a production Python / DuckDB ETL pipeline for a live U.S. discovery app: ingestion, prompt and schema-driven LLM enrichment, validation, dedup, and venue-status refreshes for 11,000+ venues across five markets at 95%+ precision.
  • Built an end-to-end recommendation system on S3 / Athena behavioral analytics with DynamoDB serving; shipped personalized ranking and a FAISS two-tower retriever, lifting offline recall@100 ~15% over the heuristic baseline.
PythonDuckDBAWSFAISSRecSys

TikTok

Software Engineer Intern · Trust & Safety, Algorithm Infra Jun · Aug 2026
  • Shipped Firefly, a production LLM agent inside an internal safety-model evaluation platform: data discovery, schema checks, sandboxed code execution, and reviewable reports, cutting analyst turnaround from hours to minutes.
  • Re-architected its synchronous SSE path into MongoDB-backed async tasks with durable state, sandbox recovery, and per-run cancellation, raising the job ceiling from 15 minutes to 3 hours.
  • Extended a Go DAG engine with backward-compatible async triggers and fixed a production concurrency deadlock with state-level retry and regression tests, restoring skip/retry across parallel evaluation runs.
GoMongoDBLLM AgentsTask OrchestrationTrust & Safety

Johnson & Johnson Medical

Innovative Research Intern · CDO MT Jul · Aug 2025
  • Built a Python + SQL pipeline normalizing AI-product data from 20+ global smart-surgery companies across 5+ domains.
  • Automated benchmarking with rule-based and ML-driven workflows, cutting manual evaluation effort ~60%.
  • Optimized batch-processing and SQL bottlenecks for ~2.5× lower end-to-end latency for digital scientists.
PythonSQLML BenchmarkingHealthcare AI

iQIYI

Applied ML Engineer Intern · Intelligent Platform Feb · Jul 2025
  • Productionized agent-driven image-generation pipelines in PyTorch: ~30% lower latency, 15+ GPU memory, data-pipeline, and runtime failures resolved.
  • Fine-tuned and managed a fleet of LoRA adapters for style-controlled generation with batch inference and rapid version switching.
  • Modules adopted by 3+ commercial projects, one generating ¥10K+ revenue in a single weekend; LLM translation + video restoration improved perceptual quality ~15 to 20% (PSNR/SSIM).
PyTorchLoRADiffusionComputer Vision

UAES (United Automotive Electronic Systems)

Capstone Team Lead · Differential OTA Updates 2024 · 2025
  • Led a 5-person capstone team building an over-the-air differential update system for vehicle ECUs on Linux: C/C++ delta-patch generation shipping only what changed instead of full firmware images.
  • Built the installer with MD5 verification and rollback, so a half-applied update always ends completed and verified or fully undone; a Python + shell toolchain made releases versioned and repeatable across firmware variants.
  • Cut update package size by 60%+ and end-to-end update time by 70%+; delivered as a documented solution now reused internally at UAES.
C/C++Embedded LinuxOTAReliability

SJTU Network & Information Center

Full-stack Developer Jun · Aug 2024
  • Built a campus-scale ML service platform with Django APIs serving 40,000 users and 5,000+ model-driven interactions.
  • Fine-tuned LLaMA-2 with PEFT (LoRA) for a +22% gain on internal benchmarks.
  • Deployed async inference (Uvicorn/Gunicorn) with load balancing: +20% throughput, 99.9% availability at peak.
DjangoLLaMA-2 / PEFTAsync InferenceScaling
03 · Selected projects

Things I've built.

/01

Conversational Agent Evaluation

Prof. Zhou Yu's lab · Columbia

Research on how to evaluate production conversational LLM agents: what goes wrong in real dialogues, which failures matter most, and how to close the loop without new live traffic.

Working across turn-level analysis, ranking of failure patterns, and user simulation on real customer-service conversations.

Details stay under wraps until publication.

LLM EvalNLPUser SimulationResearch
/02

Nightwatch · Multi-Agent Personal AI

24/7 agent infrastructure on macOS

Long-lived multi-agent daemon: PID locking, signal handling, launchd batch jobs, structured incident logs, shell-level command interception.

5-layer memory (SQLite FTS5 + ChromaDB): sub-100ms recall at 100K+ entries with daily GC and graceful degradation.

3-layer rate limiting + circuit breakers keep misbehaving agents inside API quota.

Multi-AgentSQLite FTS5ChromaDBReliability
/03

RCRI · Climbing Route ID & Beta Solver

Real-time CV on the edge

Three-stage YOLOv8 pipeline (hold detection, 5-class type, volumes): mAP50 0.825 on hold detection.

Exported to ONNX, quantized to TensorRT FP16 on Jetson Nano: 12 FPS single-stage, 5 FPS full pipeline at 5W.

A* beta solver with scale-invariant reach recommends optimal move sequences via a Flask MJPEG WebUI.

YOLOv8TensorRTJetsonA* Search
/04

Helm · LLM-Orchestrated Quant System

Agent as decision orchestrator

LLM agent orchestrates macro analysis, multi-factor scoring, RL portfolio optimization, and news, behind a schema + risk + anomaly validation layer.

Multi-model routing picks vendor and model size per task: under $15/month for weekly rebalancing over a 100-stock universe.

Every decision recorded as a structured audit log for offline post-mortems and prompt/policy refinement.

LLM RoutingRLMulti-factorAudit Trail
/05

Distributed Lock Service, TLA+-Verified

Formal methods meet systems

Lease-based distributed lock with fault-tolerant renewal across crash and message-loss failure models.

TLA+ spec model-checked with fault injection: mutual exclusion, lease validity, and monotonicity invariants proven.

Property-tested the Python implementation with Crosshair, surfacing race conditions in lease handoff.

TLA+Distributed SystemsProperty Testing
/06

Pinyin Communication Badge for ASD Children

Assistive AI on a Raspberry Pi

Real-time multimodal pipeline: Pinyin parsing, error correction, ranking, and speech/image feedback under <1s end-to-end latency.

Trie retrieval + probabilistic correction + LLM fallback rerank reach >95% accuracy on noisy input.

Async LLM calls with non-blocking UI and fallbacks on resource-constrained hardware.

Edge AIMultimodalRaspberry PiAccessibility
/07

Desk Companions · 3D Desktop Pets for macOS

Native Swift shell + three.js, image to rigged 3D

Anime characters living on the desktop: image to 3D mesh (Hunyuan3D), auto-rigged, walk cycles and spell animations rendered with three.js + three-vrm inside a transparent, always-on-top WKWebView.

They actually do things: calendar reminders via EventKit, a drag-and-drop "magic shelf" for files, clipboard capture, screen snipping, and face-based photo sorting from the right-click menu.

Five characters shipped as standalone .app bundles with a one-script build; 2D sprite-sheet and 3D variants share the same Swift host.

Swift / AppKitthree.jsHunyuan3DRigging
/08

Atlas of Wonders · Interactive Travel Map

Hand-built d3-geo atlas, one self-contained HTML file

My U.S. trips as a magical interactive map: per-trip diaries, hand-drawn route animation, and venue markers reconstructed by running OCR over my own photos.

Build pipeline turns raw GPS, photos, and notes into a single static page; a public build strips every personal photo so the shareable version carries zero private data.

Zero frameworks at runtime, works offline, renders on a phone.

d3-geoVision OCRData PipelineVanilla JS

mbook · Deterministic Limit Order Book

C++17: O(1) dense tick ladder over a preallocated slab, no hot-path allocation, replay-verified determinism.

cs-interview-coach · Local-first Knowledge Coach

Tauri + SvelteKit + Rust: sub-ms FST search, FSRS spaced repetition, 140+ cards across DSA/ML/LLM/RecSys.

Facial Profile Analyzer · In-browser CV

Measures ten facial profile angles from a side photo, entirely client-side; shows population norms, uploads nothing.

Fall Sim · Live Desktop Wallpaper Game

Click-to-fall stress-relief game with combo scoring and depth-themed stages; runs as a live wallpaper via Lively.

Family Portrait · 3D Face Reconstruction

Faces to studio-style group portraits via Gaussian splatting with relighting; environment and object stage validated on a 4090.

VT-Refine-Lang · Robot Manipulation

Natural language to robot insertion depth: 4-tier router, 100% on a 372-case evalset (ALOHA bimanual).

gmail-digest · Rules-first Inbox Triage

Several inboxes into one Discord feed; the optional LLM pass must quote the email for every judgment it makes.

xhs-bilibili-distill · Video Distillation

One pipeline, two source adapters: transcript + scene-detected key frames + structured report.

FitMaster · Tool-Calling AI Coach

Local-first fitness app: Claude/GPT-4V coach with 16+ tools, voice + image input, 13 toggleable modules.

HabitLedger · P2P Blockchain

Proof-of-work chain in Python: Ed25519 transactions, fork resolution, mempool recovery on reorg.

LuxRent · Microservices Backend

Spring Boot microservices on AWS ECS with CI/CD, MySQL/MongoDB, and CloudWatch observability.

DeStudy · Web3 Notes NFT

Solidity + Hardhat contracts (no high-severity Slither findings, 100% test coverage) with Next.js + wagmi frontend.

04 · Toolbox

What I work with.

Agents & LLMs

LLMs / SLMsRAGTool Use MCPAgent Evaluation Prompt EngineeringUser Simulation

Computer Vision & Imaging

YOLOv8 / DetectionDiffusion & LoRA Computational ImagingGaussian Splatting OpenCVImage ProcessingMultimodal

ML Engineering

PyTorchLoRA / PEFTTensorRT ONNXJetson EdgeHuggingFace FAISS / Vector SearchNLP

Backend & Infra

GoPythonC/C++Java MongoDBDuckDBKafkaRedis DockerKubernetesAWSCI/CD
05 · Coursework

What I've studied.

Columbia University
M.S. Computer Engineering · 2025 to Dec 2026
  • Cloud Computing
  • Natural Language Processing
  • Computational Imaging
  • Deep Learning on the Edge
  • Deep Learning for Robotic Manipulation
  • Formal Verification of HW/SW Systems
  • Modeling & Performance Evaluation
  • Computer Networks
  • Web3 & Blockchain Applications
  • Data Center Processing in progress
  • Advanced Master's Research, Prof. Zhou Yu's lab in progress
UM-SJTU Joint Institute
B.E. Electrical & Computer Engineering · 2021 to 2025
  • Data Structures & Algorithms
  • Computer Architecture
  • Artificial Intelligence
  • Image Processing
  • Data Science & Analytics
  • Database Systems
  • Web Development
  • Stochastic Processes
  • Functional Analysis
  • Probability · Discrete Mathematics
New York University
Exchange · Spring 2024
  • Operating Systems
  • Computer Networks
  • Web Systems
  • AIoT
  • Hardware & Software Co-design
  • Introduction to Animation Technology
06 · Photography

What I see when I put the laptop down.

I shoot on a Canon R6 Mark II, mostly travel and portraits. Here's a first set from Peru; the archive is big and I'm bringing it over slowly.

07 · Contact

Let's build something
that actually ships.

Open to 2027 new-grad and internship roles in software engineering, machine learning, computer vision, and agent systems. I reply fast.

New York, NY · yj2923@columbia.edu