Ian H. Witten

Ian Hugh Witten was a computer scientist at the University of Waikato in New Zealand, born in Horsham, Sussex, England on 4 March 1947 and died on 5 May 2023. He studied mathematics at the University of Cambridge, took a master's degree in mathematics and computer science at the University of Calgary as a Commonwealth Scholar, and received his doctorate from the University of Essex in 1976. He is credited with discovering temporal-difference learning, inventing the tabular TD(0) rule, the first temporal-difference learning rule for reinforcement learning. He was a co-creator of the Sequitur algorithm, conceived and obtained funding for the original WEKA data mining software, and worked with Alistair Moffat and Timothy Bell on algorithms for text and image compression. He was also a major contributor to digital libraries and founded the Greenstone Digital Library Software. His doctoral students included Craig Nevill-Manning and Saul Greenberg. He became an ACM Fellow in 1996, a Fellow of the Royal Society of New Zealand in 1997, received the IFIP Namur Award in 2004 and the Hector Medal in 2005, and retired in 2014 as professor emeritus.