Professor Yuen is an internationally recognized expert in plant pathology, plant disease epidemiology, modelling, and statistics. He has published over 100 research citations, of which over 75 are journal articles or chapters in scholarly books. He has served as the principal or assistent advisor to a number of doctoral students in the US and in Sweden. In the past ten years, he has received the equivalent of over 15 million SEK in grants. He has taught a number of specialized courses at both the undergraduate and postgraduate level in both English and Swedish.
Prior to his first academic position in 1985, he served with the Asian Vegetable Reseach and Development Center in Taiwan.
Professor Yuen has served on the Graduate Faculty appointment board (docentnämnd) as well as on the University Faculty Appointment Board of both the JLT and NL faculty at SLU. He has served on external evaluation committees for other doctoral students at SLU and other universities, and has been the primary external examiner at doctoral thesis examinations. He has also served as a consultant reviewing grants and other applications for the European Commission (within the INCO-DEV program), The International Union Against Cancer, DANIDA, UMB/NLH, KU/KVL, Norges Forskningsråd and the Swiss Centre International Agriculture. Sida regarding matters relating to the Consultative Group on International Agriculture (CGIAR) from 2006-2007.