Nathan Chen

Logo

Aspiring Data Scientist/Analyst with internship experience across SaaS, AI, and FoodTech. Recent Data Science graduate from UC Berkeley. Passionate about AI. US Citizen

View my LinkedIn Profile

View My GitHub Profile

Portfolio

4 selected projects in data science, machine learning, NLP and vibe coding


Work Experience

Data Science Intern @ Botrista (August 2025 - Present)

Data Science Intern @ Splashtop (May 2024 - August 2024)

Data Science Intern @ Ozaru (February 2024 - May 2024)


Projects


LLM Persona Fine-Tuning: The “Wednesday Addams” Chatbot

Developed a reusable fine-tuning pipeline to adapt open-source Large Language Models (LLMs) to specific personas or domain requirements. Tested with GPT and Llama. As a proof of concept, I engineered a chatbot with the distinct personality of Wednesday Addams (Netflix). Since no public dataset existed, I manually curated and formatted a custom dialogue dataset from the show’s scripts. I utilized QLoRA (Quantized Low-Rank Adaptation) and 4-bit quantization to fine-tune the model efficiently on my laptop with minimal computational cost.

Python PyTorch Hugging Face QLoRA

View Project Folder on GitHub


My Own Chess App

Developed a fully functional chess application with claude code to solve unlimited puzzles. Engineered the core game engine from scratch to enforce strict chess rules, including valid move generation, check/checkmate state detection, castling, and en passant. The frontend interface features interactive piece selection, legal move highlighting, a dynamic move history log, and a captured pieces tracker to provide a seamless user experience.

Gameplay Interface Demo:

Chess App Demo
Figure 1: Interactive Chess GUI and Move Logging

Claude Code Python React Vite Tailwind CSS OOP

View Project Repository


Ensemble Machine Learning for Sentiment Analysis on Amazon Reviews

Predicting customer satisfaction from text is a core challenge in e-commerce. In this project, I formulated star-rating prediction as a binary classification task, distinguishing 5-star reviews from lower ratings using Natural Language Processing (NLP). I created a custom ensemble (“Blending”) model that stacked Logistic Regression, CART, Random Forest, and Gradient Boosting classifiers, optimizing their weights via OLS regression to achieve a 16% accuracy improvement over the baseline.

Selected Project Figures:

ROC Curve
Figure 1. Logistic Regression ROC Curve
Feature Importance
Figure 2: Random Forest Most Important Features

Model Comparison Table
Figure 3: Model Comparison

Python Scikit-Learn Pandas NLTK Ensemble Learning

View Notebook on GitHub


7 Million Demand Elasticities: Visualizing the “Retail Apocalypse”

Collaborated with researchers from the San Francisco Fed and UChicago on the “Seven Million Demand Elasticities” (7MDE) project to investigate if broadband proliferation caused a decline in brick-and-mortar retail. Developed an interactive R Shiny dashboard to visualize over 7.5 million price elasticity estimates across 14,000 products. The analysis revealed no negative correlation between broadband usage and in-store consumer activity, challenging the retail apocalypse hypothesis.

Project Visualizations:

R R Shiny GIS

View Project Repository
View Official Poster