Doctor Hiroyuki Sato received his bachelor of engineering degree from the Faculty of Engineering, Kyoto University, Japan, in 2009 and his master and doctor of informatics degrees from the Graduate School of Informatics, Kyoto University, in 2011 and 2013, respectively. Following graduation, from 2013 to 2014, he was a research fellow of the Japan Society for the Promotion of Science. Subsequently, from 2014 to 2017, he worked as an assistant professor in the Faculty of Engineering, Tokyo University of Science, Japan. Further, from 2017 to 2018, Doctor Sato was employed as an assistant professor in the Hakubi Center for Advanced Research, Kyoto University. Currently, he is an associate professor in the Department of Applied Mathematics and Physics, Graduate School of Informatics, Kyoto University.Doctor Sato has been studying Riemannian optimization, that is, geometric optimization on Riemannian manifolds. His research interests include the theory of Riemannian optimization algorithms, such as the Riemannian conjugate gradient methods, and their applications to problems in other fields. His works contribute to developing the Riemannian optimization theory and proposing Riemannian optimization algorithms for problems arising in applications. Because Riemannian optimization is an interdisciplinary research field with diverse applications, Doctor Sato routinely collaborates with researchers across various fields, including numerical linear algebra, control engineering, and statistics.