Lloyd R. Welch

Lloyd Richard Welch ( born September 28, 1927 in Detroit, Michigan) is an American mathematician who deals with coding theory.

Welch studied mathematics at the University of Illinois with a bachelor 's degree in 1951 and in 1958 at Frederic Bohnenblust at Caltech PhD (The rearrangement of functions and maximization of a convolution integral). From 1956 to 1959 he was at the Jet Propulsion Laboratory, 1969 to 1965 at the Institute for Defense Analyses; In 1965 he became a professor at the University of Southern California. In 1999 he retired.

He is known among other things for the MMRW - bounds for binary codes ( with Robert J. McEliece, R. Rodemick, Howard Rumsey ) and the Baum-Welch algorithm (also named after Leonard E. tree, the end of the 1960s at the Institute for Defense Analyses pioneering work on HMM undertook and published in 1970 ) for the determination of the parameters in a Hidden Markov Model (HMM ). His contribution is in its Shannon Lecture 2003. According to him and Elwyn Berlekamp Welch - Berlekamp algorithm is named for efficient error correction in BCH and Reed- Solomon codes.

He is a Fellow of the IEEE and the National Academy of Engineering. In 2003 he received the Claude E. Shannon Award.

Writings

• Lower Bounds on the Maximum Cross Correlation of Signals, IEEE Transactions on Information Theory, Vol IT -20, pp. 397-399, 1974.
• RJ McEliece, R. Rodemick, H. Rumsey New Upper Bounds on the rate of a code via the Delsarte - Mac Williams Inequalities, IEEE Transactions on Information Theory March 1977.
• With W. Ke Binary Sequences with Non- Positive Autocorrelation Values, ACTA Electronics Sinica September 1982.
• With J. Olsen, RA Scholtz Bent Function Sequences, IEEE Transactions on Information Theory, Nov. 1982.
• RA Scholtz GMW sequences, IEEE Transactions on Information Theory, May 1984.
• PV Kumar, RA Scholtz Generalized Bent Functions and Their Properties, Journal of Combinatorial Theory, September 1985,