Koby Hayashi
About Me
I’m a Machine Learning Engineer at Pacific Northwest National Laboratory, where I work on projects ranging from using LLM’s to improve the Enviornmental permitting process to developing simulation codes for improving energy efficiency at Commercial Ports.
Previously, I completed my PhD in Computational Science and Engineering at Georgia Tech’s College of Computing, advised by Haesun Park and Richard Vuduc. My doctoral research was supported by the DOE Computational Science Graduate Fellowship.
Current Work
At PNNL, I focus on:
- LLM Development: Fine-tuning and training large language models
- Evaluation & Benchmarking: Designing custom evaluation frameworks and LLM-as-Judge metrics for domain-specific applications
- Infrastructure & Optimization: Building scalable ML pipelines and optimizing compute infrastructure to help reduce project costs
- Applied Research: Working on research projects to help fufull DoE missions
Research Interests
My research sits at the intersection of machine learning, high-performance computing, and data science. I’m particularly interested in:
- Large Language Models: Training, fine-tuning, and evaluation of LLMs; long-context modeling
- Scalable Machine Learning: Designing algorithms that efficiently handle massive datasets and leverage parallel/distributed computing
- Graph & Network Analysis: Spectral methods, hypergraph clustering, and representation learning for complex relational data
- Numerical Optimization: Low-rank matrix and tensor factorizations with applications to dimension reduction and data mining
- ML Systems & Infrastructure: Building robust, efficient pipelines that enable research at scale
The common thread in my work is developing principled, scalable methods that combine strong theoretical foundations with practical performance—whether that’s training models on thousands of GPUs or clustering networks with millions of nodes.
Open Source & Impact
I’m a contributor to PLANC, an open-source C++ library for scalable non-negative matrix factorization and dimension reduction.
You can find my publications on Google Scholar.
Contact: hayakb95@gmail.com
Location: Atlanta, GA