Siyan is a medical doctor and infectious disease epidemiologist by training, holding a Ph.D. in international health from the University of Tokyo and trained as a postdoctoral fellow at Stanford University’s Asia Health Policy Program. As an Assistant Professor at the Saw Swee Hock School of Public Health, National University of Singapore, he leads a regional integrated research program, serves as the Director of the KHANA Center for Population Health Research in Cambodia, and holds the title of Adjunct Associate Professor at Touro University California in the United States. His implementation research program focuses on innovative community-based interventions to improve access to services and health outcomes, benefiting vulnerable and marginalized populations in low- and middle-income countries.