Hello there, welcome!
My name is Charles but everyone calls me Charlie. I am a postdoctoral researcher in the Computer Science department at Aalto University, working at the intersection of natural language processing and computing education. I am developping methods and frameworks for aligning language models with pedagogical objectives, with applications in automated programming feedback generation and evaluation, and simulated learners. I focus particularly on lightweight, open models that can be safely deployed in educational contexts.
My PhD dissertation laid the groundwork for this.
Recent News
30th April 2026
Our paper, “Teaching Language Models How to Code Like Learners: Conversational Serialization for Student Simulation” was accepted at EDM2026! I’ll present the paper in Koreea.
20th February 2026
I have succesfully defended my PhD!
5 December 2025
My Ph.D thesis has been accepted for defense! Defense information
15 September 2025
Two papers accepted at SIGCSE TS 2026!
- Aligning Small Language Models for Programming Feedback: Towards Scalable Coding Support in a Massive Global Course (first author)
- Fine-Tuning Open-Source Models as a Viable Alternative to Proprietary LLMs for Explaining Compiler Messages (second author)
The first came out of my research visit at Stanford, we also put together a presentation page. The second is a collaboration with researchers at The University of New South Wales.
27 May 2025
Paper accepted at CSEDM 2025: “Reinforcement Learning for Programming Feedback: Aligning Small Language Models Without Human Preferences” (first author).
24 May 2025
Paper accepted at BEA 2025: “Direct Repair Optimization: Training Small Language Models for Educational Program Repair Improves Feedback Abilities” (first author).
2 May 2025
Gave a talk at Berkeley’s ACE Lab on feedback generation with small language models.
1 April 2025
Started a research visit at the Piech Lab at Stanford University (through June 2025).