About Me

I am Rikiya Takehi, a third-year undergraduate student at Waseda University, where I am honored to be supervised by Prof. Tetsuya Sakai.
Previously, I was a guest researcher at NIST in the US for one year, working with Dr. Ian Soboroff and Dr. Ellen Voorhees, conducting research mainly on evaluation.
I also collaborate closely with Yuta Saito of Cornell Univ., working on counterfactual learning and fairness in rankings.

I am one of the organizers of the upcoming Product Search and Recommendations Track at TREC (previously Product Search Track).

My research widely orbits around information retrieval and machine learning, particularly evaluation, counterfactual learning, and recommendation.

News

• Jan.2025: First authored paper General Framework for Off-Policy Learning with Partially-Observed Reward got accepted to ICLR 2025!
• Nov.2024: Gave an invited talk at NII about Using LLMs as Assistants for Building Test Collections invited by Prof. Noriko Kando.
• Nov.2024: First authored paper LLM-Assisted Relevance Assessments: When Should We Ask LLMs for Help? preprint available on arXiv!!
• Oct.2024: Started research internship at CyberAgent AI Lab. Algorithm Team.
• Aug.2024: Gave an invited talk at UMD College Park about Nugget-Based Evaluation and the Use of LLMs invited by Prof. Douglas Oard.
• Oct.2023: First authored paper Open-Domain Dialogue Quality Evaluation: Deriving Nugget-level Scores from Turn-level Scores accepted to SIGIR AP 2023.

Experience

• Research Intern at CyberAgent AI Lab. Algorithm Team, Tokyo, Japan. Oct 2024 - Present
• Guest Researcher at National Institute of Standards and Technology (NIST) Retrieval Group, Maryland, US. Oct 2023 - Sep 2024
• Research Intern at Hakuhodo Tech Inc. / Negocia Inc., Tokyo, Japan. Sept 2023 - Oct 2024
• Research Intern supervised by Yuta Saito of Cornell Univ. 7/1/2023 - Present