SDE · MLE · Agent Engineering — New York

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

M.S. Computer Engineering @ Columbia · 4.0 GPA. Currently Algorithm Infra Intern @ TikTok; previously Johnson & Johnson and iQIYI. I make LLM agents and ML systems measurable, debuggable, and reliable.

4.0
Columbia GPA
5
Internships & research
12+
Projects built
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 (4.0 GPA) with five internships and research roles across TikTok, Johnson & Johnson Medical, iQIYI, 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 an agent-evaluation platform for production conversational AI. If it involves a model meeting the real world, I've probably debugged it at 2 a.m.

Off the clock I'm usually 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–engineering line.

Currently

  • Algorithm Infra Intern @ TikTok — Trust & Safety model platform
  • Agent-evaluation research @ Columbia — project with Walmart Global Tech
  • Graduating Dec 2026 — open to 2027 SDE / MLE / Agent roles
02 · Experience

Where I've shipped.

TikTok

Algorithm Infra Intern · Data-TNS Engineering Jun 2026 — Present
New York, NY
  • Migrated model serving from personal devboxes to a team-shared deployment platform — 25+ production content-safety models now jointly operated with standardized releases.
  • Automated multi-datacenter deployment with operator auto-registration and PSM switching across 120+ daily deploys.
  • Improved agent-evaluation accuracy ~15% with region-aware scoring and Top-K case surfacing before launch.
Model ServingDeployment InfraAgent EvaluationTrust & Safety

Johnson & Johnson Medical

Innovative Research Intern · CDO MT Jul — Aug 2025
Shanghai, China
  • 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
Shanghai, China
  • Built agent-driven image-generation pipelines in PyTorch — ~30% lower latency, 15+ production issues 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 generated ¥10K+ revenue in a single weekend; LLM translation + video restoration improved perceptual quality ~15–20% (PSNR/SSIM).
PyTorchLoRADiffusion PipelinesProduction ML

SJTU Network & Information Center

Full-stack Developer Jun — Aug 2024
Shanghai, China
  • 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 Platform

Walmart Global Tech · Columbia research

Turn-level attribute mining + concept clustering over thousands of production customer dialogues (NER, intent, knowledge-grounding signals).

Custom ranking (failure_lift / success_lift) surfaces highest-impact agent errors — validated against human annotations across 5 rating tiers.

Traffic-matched user simulator enables closed-loop agent improvement without fresh live conversations.

LLM EvalNERClusteringUser Simulator
/02

An-agent — 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.

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

YOLOv8TensorRTJetsonA* Search
/04

Stockbee — 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

HabitLedger — P2P Blockchain

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

VT-Refine-Lang — Robot Manipulation

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

LuxRent — Microservices Backend

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

FitMaster — Tool-Calling AI Coach

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

UAES — Automotive OTA Diffs

Led a 5-person team: differential upgrade packages 60%+ smaller, update time down 70%+. Adopted by UAES.

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 Multi-step PlanningAgent Evaluation Prompt EngineeringUser Simulation

ML Engineering

PyTorchLoRA / PEFTTensorRT ONNXComputer VisionNLP MultimodalHuggingFaceJetson Edge

Data & ML Systems

FAISS / Vector SearchKafkaSpark RedisSQLML Pipelines Batch & Streaming

Backend & Infra

PythonJavaC/C++ FastAPIDjangoSpring Boot DockerKubernetesAWSCI/CD
05 · Contact

Let's build something
that actually ships.

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

New York, NY · yj2923@columbia.edu