Complex sentence: From 1998 to 2000 he served as an Assistant Professor at Emory, where he was awarded the Teacher of the Year award in his department, and then in 2000 began his tenure as Associate Professor at the University of California at San Diego.
Split into simpler sentences: From 1998 to 2000 he served as an Assistant Professor at Emory, where he was awarded the Teacher of the Year award in his department. In 2000 he began his tenure as Associate Professor at the University of California at San Diego.