His research areas are the theory of self-organization, associative memories, neural networks, and pattern recognition, in which he has published over 300 research papers and four monography books. His fifth book is on digital computers. His more recent work is expounded in the third, extended edition (2001) of his book Self-Organizing Maps.
Since the 1960s, Professor Kohonen has introduced several new concepts to neural computing: fundamental theories of distributed associative memory and optimal associative mappings, the learning subspace method, the self-organizing feature maps (SOMs), the learning vector quantization (LVQ), novel algorithms for symbol processing like the redundant hash addressing, dynamically expanding context and a special SOM for symbolic data, and a SOM called the Adaptive-Subspace SOM (ASSOM) in which invariant-feature filters emergence. A new SOM architecture WEBSOM has been developed in his laboratory for exploratory textual data mining. In the largest WEBSOM implemented so far, about seven million documents have been organized in a one-million neuron network: for smaller WEBSOMs, see the demo at http://websom.hut.fi/websom/.
Professor Kohonen is recipient of the Honorary Prize of Emil Aaltonen Foundation in 1983, the Cultural Prize of the Finnish Commercial Television (MTV) in 1984, the IEEE Neural Networks Council Pioneer Award in 1991, the International Neural Network Society Lifetime Achievement Award in 1992, Prize of the Finnish Cultural Foundation in 1994, 1995 Technical Achievement Award of the IEEE Signal Processing Society, Centennial Prize of the Finnish Association of Graduate Engineers (TEK) in 1996, King-Sun Fu Prize of the International Association for Pattern Recognition in 1996, Jubilee Prize of the Finnish Foundation of Technology (TES) in 1999, Italgas Prize in 1999, and others. He received the honorary title of Academician in March, 2000. He is also Honorary Doctor of the University of York in U.K., Universität Dortmund in Germany, and Åbo Akademi in Finland, member of Academia Scientiarum et Artium Europaea, titular member of the Academié Européenne des Sciences, des Arts et des Lettres, member of the Finnish Academy of Sciences and the Finnish Academy of Engineering Sciences, IEEE Fellow, and Honorary Member of the Pattern Recognition Society of Finland as well as the Finnish Society for Medical Physics and Medical Engineering. He was elected the First Vice President of the International Association for Pattern Recognition for the period 1982 - 84, and acted as the first President of the European Neural Network Society during 1991 - 92.
The more recent work of Professor Kohonen is expounded in his newest book Self-Organizing Maps, Springer Series in Information Sciences, Vol. 30, 1995; Second edition, 1997; Third, extended edition, 2001.