Profile

Shusei Yokoi

Data Scientist / Research Assistant

Data Scientist with a focus on trustworthy and interpretable AI. Currently pursuing an M.S. in Applied Data Science at USC and conducting trustworthy AI research at ISI.
I build data-driven solutions with strong software engineering skills and a business-driven mindset. I work end-to-end across the data science lifecycle, from defining business problems and analyzing data to evaluating models and deploying solutions that solve real-world problems.

— Turning Data into Smiles.

Experience & Education

Resume

Research Experience

USC Information Sciences Institute (ISI)

Research Assistant

2026 – Present

Bias by Prompt LLM Fairness | Python, ChatGPT, Claude, Gemini, Qwen

  • Conducting research on trustworthy AI, focusing on fairness, bias, and reliability in LLM-based decision-making
  • Designed controlled experiments to evaluate the effects of prompt framing on responses across LLMs, including ChatGPT, Claude, Gemini, and Qwen
  • Identified early evidence that emotional prompt framing can alter LLM behavior, causing conclusion shifts in some models and reduced confidence in others

Professional Experience

Datify

Founder / AI Product Developer

2025 – Present

Founded and Developed an AI-powered Solutions | R, Python, Swift, Azure OpenAI

  • Founded Datify to build AI-powered products that help people improve their lives through personalization
  • Developed HealthSync, an iOS AI health advisor app integrating Apple HealthKit and Azure OpenAI GPT-4o to deliver personalized health insights from biometric and activity data
  • Built data pipelines to extract biometric data from Apple HealthKit and convert them into structured summaries for AI analysis to generate dynamic, contextual health advice, helping users track trends and stay on target with personal goals

SoftBank

Data Scientist

2022 – 2024

Gym Chain Health Data Analysis | R, SQL

  • Analyzed 200,000 member records for a gymnasium company with 150+ branches across Japan.
  • Identified a 3-month weight regain trend in younger members and developed tailored retention strategies.
  • Implemented a notification service to re-engage inactive members, increasing re-engagement rate by 30%.

Software Development Team Productivity Analysis | SQL, Python, R

  • Performed Difference-in-Differences analysis on ticketing system data to diagnose productivity bottlenecks.
  • Found resource allocation inefficiencies and recommended more frequent ticket creation and resource optimization.

SoftBank

Technical Project Manager

2022 – 2024

Led Application Development | AWS, Azure, JavaScript, GitLab, SQL, VoltMX

  • Directed end-to-end development of a multi-platform office management system for teams in Vietnam, China, and Japan.
  • Led UI/UX design, back-end architecture, testing, and cross-platform deployment.

SoftBank

Data Scientist Contractor

2020 – 2022

Trade Area / Population Flow Analysis | Tableau, SQL, Python, R

  • Led trade area analysis for Izumi Co. with 190+ malls under SoftBank's Smart City project.
  • Built Tableau dashboards using GPS, demographic, and search data to uncover customer trends.
  • Recommended targeted ads, in-store improvements, and loyalty strategies based on retention and regional growth insights.

AI Engineer | Python, SQL

  • Developed a population inflow prediction model to optimize billboard advertising placement.
  • Improved model performance through data engineering and feature design, achieving an AUC of 0.70.

ABC Cooking Studio

Data Scientist Intern

2020

EC Site Analysis | SQL, Python, R, Google Analytics

  • Analyzed EC site traffic using Google Analytics and modeled sales patterns across product categories.
  • Predicted product sales using a multilevel model with category-specific price elasticity.

Education

University of Southern California

M.S. Applied Data Science

Expected 2027

Focused on machine learning, trustworthy AI, LLM evaluation, and real-world data science applications.

California Polytechnic State University, San Luis Obispo

B.S. Business Administration, Information Systems / Minor in Statistics

2021

Data Science & Statistics

Statistical learning, regression analysis, multilevel and mixed modeling, categorical data analysis, statistical computing in R, time series, forecasting, and model evaluation.

Programming & Systems

Python application development, database systems, ERD/UML, advanced SQL, systems analysis, SDLC, UI/UX requirements, project management, and blockchain development.

Projects

Ask Me project image

Ask Me

An agentic AI chatbot with RAG-based reasoning that answers my career related questions.

RAGLLMAWSCHATBOT
Bias by Prompt in LLM project image

Bias by Prompt in LLM

Shows that basic LLMs can change conclusions from the same loan data depending on prompt framing.

LLMFairness of AI
HealthSync project image

HealthSync

An iOS app that syncs HealthKit data and delivers personalized health advice using Azure OpenAI.

TYPESCRIPTLLMSWIFTIOS
How Hot project image

How Hot

Predict food spiciness from images using deep learning, with user feedback for continual improvement.

Human in the loopMLOpsResNet