Data Engineering · Applied AI · Statistics

David Zhihao Xu

University of Waterloo student focused on data engineering and applied AI — building Python workflows that turn raw data into structured outputs and useful tools.

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Data Workflows

Python, SQL, data cleaning, validation, and structured outputs

Applied AI

API integration, source-grounded drafts, and human review workflows

Statistics

Regression, experimental design, and interpreting model outputs

About

Building reliable data workflows and practical AI tools.

I study Statistics, Mathematics and Finance at the University of Waterloo, with a growing focus on data engineering and applied AI. I enjoy the work behind a useful data product: bringing together messy inputs, checking their quality, and building repeatable Python and SQL workflows that produce clear, usable outputs.

My projects connect that foundation to real tasks, from transaction analysis to PayPal Cancellation Assistant, an AI-assisted merchant review tool. Through this project, I built API integrations, structured AI outputs, review history, and payment safeguards. I am looking for opportunities in data engineering and AI application development where I can keep building reliable systems and solve practical business problems.

Selected Work

Data workflows, applied AI, and business analysis.

PayPal AI Hackathon · Node.js · Express · OpenAI API · PayPal REST APIs

PayPal Cancellation Assistant

Built an AI-assisted workflow that turns customer cancellation requests into structured merchant reviews. It extracts order references and customer conditions, preserves review history, and supports explicitly approved voids of eligible uncaptured PayPal Sandbox authorizations.

Extract order references, cancellation intent, and conditions using strict structured AI outputs.
Save and reopen merchant findings with notes, timestamps, and previous conclusions; block conditional requests from payment execution.
Require merchant confirmation and backend order, amount, and capture checks before a Sandbox void, then independently verify the result.

Includes a credential-free local mock demo for review and history, plus documented OpenAI and PayPal Sandbox verification. Built with Node.js, Express, and vanilla JavaScript.

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Python · Pandas · CSV/JSON Workflows · Regression

Pricing Analytics MVP

Built an end-to-end CSV analysis workflow that processes transaction data, generates business summaries, estimates pricing opportunities, simulates A/B tests, and renders a decision-ready dashboard.

Processed 100K+ transaction records through a reusable analytics pipeline.
Used log-log regression to estimate price elasticity by category and price tier.
Generated JSON outputs for KPI cards, revenue trends, uplift charts, and recommendations.

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Equity Research · Valuation · DCF

Sportswear Equity Research Pitch

Researched a high-growth sportswear and accessories company using financial statements, valuation multiples, industry benchmarking, and a five-year DCF model.

Analyzed five years of revenue growth, margins, and strategic positioning.
Benchmarked against five major competitors to support an investment thesis.

Skills

Tools for data engineering and applied AI.

Programming

Python, R, JavaScript, C, HTML, CSS

Data Workflows

SQL, MySQL, PostgreSQL, Pandas, NumPy, Data Cleaning, Data Validation, CSV/JSON Processing

Analysis & Development

Regression, Experimental Design, A/B Testing, Excel, Power BI, Git, GitHub, Python/JavaScript Testing

Applied AI

OpenAI API Integration, Structured Model Outputs, Prompt Iteration, Source-Quote Checks, Human Review

Education

A statistical foundation for data and AI work.

University of Waterloo

Bachelor of Statistics, Mathematics and Finance

Relevant coursework: Linear Regression, Experimental Design, Algorithms and Data Structures, Statistical Data Analysis, Numerical Methods.

Charlottetown Rural High School

Student Council Vice President

Democratically elected to represent a student body of 500+.
Organized the first post-pandemic Winter Formal and a successful Grad Breakfast as Vice President.

Outside the Classroom

Personal habits that keep me curious and balanced.

Basketball

Travel

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