Obituary—Prof. Dr. Yangquan Chen

It is with deep sadness that we share the news of the passing of Prof. Dr. Yangquan Chen, Section Editor-in-Chief of Fractal and Fractional, on 27 April 2026. We are truly grateful for his contributions to the journal and for the lasting impact of his work on the academic community.

Prof. Dr. Chen was a distinguished scholar and dedicated educator. He served as professor of mechanical engineering at the University of California, Merced, where he led the Mechatronics, Embedded Systems, and Automation (MESA) Lab. His research spanned control systems, mechatronics, unmanned aerial systems, and fractional calculus, and he was widely recognized for his innovative and interdisciplinary approach. Throughout his career, he authored a substantial body of scholarly work, mentored many students and researchers, and was named a Highly Cited Researcher by Clarivate Analytics for several consecutive years. His work has had a lasting influence on both the scientific community and the development of engineering applications.

He was known not only for his academic achievements, but also for his openness, generosity, and willingness to support others. He actively encouraged collaboration and contributed to advancing research across disciplines.

Within the Fractal and Fractional journal, Prof. Dr. Chen served as Section Editor-in-Chief of “Optimization, Big Data, and AI/ML” since 2025. He played a key role in shaping the Section, promoting high-quality research and fostering interdisciplinary perspectives on the use of fractional calculus (FC) in optimization, machine learning, and big data. His efforts significantly contributed to the growth and direction of the Section.

On behalf of the Fractal and Fractional Editorial Office and the entire journal community, we extend our heartfelt condolences to his family, friends, colleagues, and students during this difficult time.

He will be remembered for both his scientific contributions and the positive impact he had on those who had the privilege of working with him.

Fractal and Fractional Editorial Office