Joos is a Professor Emeritus with the Department of Electrical Engineering at the Catholic University of Leuven, Belgium. He is one of the most impactful researchers in Computer Science in the World, including in areas of cryptography, secure data communications, data mining and complex systems. His work has led to many areas of impact, including supervising the creators of the Advanced Encryption Standard. He has also worked to simplify the computational complexity of support vector machines, and which involved using a least-squares approach for learning-based classifiers. He has also enhanced the theory behind singular-value decomposition by extending it to multilinear dimensions, which has addressed complex data-mining challenges. Joos is also an IEEE Life Fellow and served as the President of the Royal Flemish Academy of Belgium KVAB. He also co-wrote the book defining "The Invisible Power of Mathematics".
