# Jorma Rissanen

**Jorma J. Rissanen** (October 20, 1932 – May 9, 2020) was an information theorist, known for inventing the minimum description length principle and practical approaches to arithmetic coding for lossless data compression. His work inspired the development of the theory of stochastic chains with memory of variable length.

Jorma J. Rissanen | |
---|---|

Born | 20 October 1932 |

Died | May 9, 2020 Los Gatos, California, United States | (aged 87)

Alma mater | Helsinki University of Technology |

Known for | arithmetic coding and the minimum description length principle |

Awards | IEEE Richard W. Hamming Medal (1993) Claude E. Shannon Award (2009) |

Scientific career | |

Fields | Information Theory |

Institutions | IBM Tampere University of Technology |

An IBM researcher since 1960, first in Stockholm, Sweden, and then at IBM Almaden in California, Rissanen received his Ph.D. from the Helsinki University of Technology in 1965. He stayed with IBM until his retirement in 2002, with a brief interruption in 1974 as a professor of control theory in Sweden. During that time, he became familiar with the work on algorithmic randomness by Kolmogorov and Martin-Löf, which inspired his work on MDL and arithmetic coding. Retired from IBM, he remained professor emeritus of Tampere University of Technology and a fellow of Helsinki Institute for Information Technology.

## Awards and recognitionsEdit

He was awarded the IEEE Richard W. Hamming Medal in 1993,^{[1]} an IEEE Golden Jubilee Award for Technological Innovation from the IEEE Information Theory Society in 1998,^{[2]} the Kolmogorov Medal of the University of London in 2006,^{[3]} and the IEEE Claude E. Shannon Award in 2009.^{[4]} A Festschrift collection, which includes an interview and substantial biographical information, was published by the Tampere University of Technology in honor of his 75th birthday.^{[5]}

## ReferencesEdit

**^**"IEEE Richard W. Hamming Medal Recipients" (PDF). IEEE. Retrieved May 29, 2011.**^**"Golden Jubilee Awards for Technological Innovation". IEEE Information Theory Society. Retrieved July 14, 2011.**^**Kolmogorov Medal web site, University of London.**^**"Claude E. Shannon Award Recipients". IEEE Information Theory Society. Retrieved July 1, 2015.**^**Peter Grünwald, Petri Myllymäki, Ioan Tabus, Marcelo Weinberger, and Bin Yu (eds.), Festschrift in Honor of Jorma Rissanen on the Occasion of his 75th Birthday, Tampere University of Technology, 2008.

## External linksEdit

- Professor Jorma Rissanen page at RHUL

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