Portrait of Yang Jiao

Data Scientist / ML Engineer

Yang Jiao

I'm a PhD-trained data scientist and Google Cloud Certified Professional Machine Learning Engineer with 6+ years of experience building end-to-end data and ML systems in production.

I specialize in taking models beyond notebooks—designing scalable data pipelines, deploying time-series and recommendation systems, and building internal data products that drive measurable business impact. From forecasting revenue, automating workflows to improving recommendation accuracy, I focus on reliable, maintainable, and value-generating ML solutions.

I'm deeply passionate about building robust, scalable technology and applying machine learning where it creates meaningful, measurable impact in real-world products.

See projects

Selected Projects

Job Hunting Assistant AI Agent

LLM Agent Systems · Evaluation · RAG · AWS

I built and deployed a production-oriented AI agent system for job search workflows. The assistant uses a LangGraph-orchestrated pipeline for intent classification, policy-based tool routing, guarded execution, response synthesis, telemetry, token usage tracking, and message persistence. This project showcases machine learning engineering across LLM workflow design, retrieval-augmented tool use, evaluation, backend systems, frontend UX, and cloud deployment.

Agent architecture: The core system is a tool-augmented assistant built with FastAPI, LangChain, and LangGraph. I implemented multiple AI workflows, including natural-language database querying with safety checks, AI-assisted CSV import for messy job-tracking data, schema-constrained webpage extraction for job posting ingestion, profile-aware drafting using CV and portfolio context, and semantic job search powered by Sentence Transformers embeddings and pgvector.

Evaluation and reliability: I treated the LLM workflow as a production ML system, adding deterministic policy routing, required-tool guard nodes, retry logic for transient provider failures, structured node/tool telemetry, trace propagation, and token usage tracking for cost visibility. I also built an offline routing evaluation harness with labeled datasets, saved experiment runs, route accuracy metrics, critical misroute tracking, clarification-rate analysis, and model comparison across LLM providers.

Cloud deployment: The application is containerized with Docker and deployed on AWS using ECS Fargate for frontend/backend services and Amazon RDS PostgreSQL for persistence. Delivery is automated via GitHub Actions with OIDC-based AWS auth, CloudFormation infrastructure-as-code, ECR image builds, CodeDeploy blue/green deployments, Secrets Manager for secret management, and CloudWatch for centralized logging.

Tech stack

  • ML/AI: LangChain, LangGraph, OpenAI/Anthropic/Gemini, Sentence Transformers, pgvector, routing evaluation
  • Backend & Data: FastAPI, PostgreSQL, JWT auth, structured telemetry, token usage tracking
  • Cloud & DevOps: Docker, Amazon ECS Fargate, Amazon RDS, ALB, ECR, CodeDeploy, CloudFormation, GitHub Actions, Secrets Manager, CloudWatch
  • Frontend: React 18, Vite, Zustand, Tailwind CSS, Recharts, Axios

ENTSO-E Load Forecasting App

End-to-End ML App · Time-Series Forecasting

I built an end-to-end machine learning application for forecasting day-ahead electricity load in the Germany-Luxembourg (DE-LU) bidding zone. The app ingests load data from the ENTSO-E Transparency Platform and weather data from Open-Meteo, engineers time-series features, and trains forecasting models for operational use. It includes a FastAPI backend for serving forecasts and metrics and a Streamlit dashboard for interactive monitoring and exploration.

Tech stack

  • Language: Python 3.11.
  • Data & ML: pandas, numpy, scikit-learn, LightGBM, XGBoost.
  • MLOps: MLflow.
  • Data sources: ENTSO-E API (entsoe-py), Open-Meteo API (openmeteo-requests).
  • Backend API: FastAPI, Uvicorn, Pydantic.
  • Dashboard/UI: Streamlit, Plotly.
  • Database layer: PostgreSQL, SQLAlchemy.
  • Infrastructure & runtime: Docker, EC2.
  • Developer tooling: pytest, Ruff, mypy, Makefile.

Contact

Open to data science and ML engineer opportunities.


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