Lloyd Richard Welch is a noted American information theorist, and co-inventor of the Baum–Welch algorithm.

Welch received his B.S. in mathematics from the University of Illinois, 1951, and Ph.D. in mathematics from the California Institute of Technology

California Institute of Technology

The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...

, 1958, under advisor Frederic Bohnenblust. He worked at the Jet Propulsion Laboratory

Jet Propulsion Laboratory

Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 1956–1959, Institute for Defense Analyses

Institute for Defense Analyses

The Institute for Defense Analyses is a non-profit corporation that administers three federally funded research and development centers to assist the United States government in addressing important national security issues, particularly those requiring scientific and technical expertise...

, 1959–1965, and University of Southern California

University of Southern California

The University of Southern California is a private, not-for-profit, nonsectarian, research university located in Los Angeles, California, United States. USC was founded in 1880, making it California's oldest private research university...

, 1965–1999. He is a member of the National Academy of Engineering

National Academy of Engineering

The National Academy of Engineering is a government-created non-profit institution in the United States, that was founded in 1964 under the same congressional act that led to the founding of the National Academy of Sciences...

, IEEE Fellow

IEEE Fellow

An IEEE member is elevated to the grade of IEEE Fellow for "unusual distinction in the profession and shall be conferred by the Board of Directors upon a person with an extraordinary record of accomplishments in any of the IEEE fields of interest"...

, and received the 2003 Claude E. Shannon Award

Claude E. Shannon Award

The Claude E. Shannon Award of the IEEE Information Theory Society was instituted to honour consistent and profound contributions to the field of information theory. Each Shannon Award winner is expected to present a Shannon Lecture at the following IEEE International Symposium on Information Theory...

.