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## Robert E. Bixby, ORIE Ph.D. '72, returns to Cornell to Deliver the Fulkerson Lectures on Optimization

Robert E. Bixby ORIE Ph.D. '72, the Noah Harding Professor Emeritus of Computational and Applied Mathematics and Research Professor of Management at Rice University, will deliver the twenty-second series of D. R. Fulkerson Lectures on April 21st, 23rd and 25th.

In 1987 Bixby co-founded CPLEX Optimization, Inc., which was acquired in 1997 by ILOG, Inc., a leading provider of software for business decision making. Until recently he served as Chief Scientific Officer of ILOG. ILOG CPLEX, developed by Bixby, is one of the leading software packages for large scale linear and integer optimization. In parallel to his business activities Bixby has led an active research and teaching career, holding academic positions at leading universities in the United States and Europe and publishing more than 50 papers. In 1997 he was elected to the National Academy of Engineering and in 1992 he received the Humboldt Senior Scientist Award. In 2007 Bixby and his co-authors won the Frederick W. Lanchester prize for their book *The Traveling Salesman Problem: A Computational Study*. The problem addressed in this book is the archetype of a class of computational problems known to be extremely difficult to solve.

The Fulkerson lectures will examine the computational state-of-the-art in linear and integer programming, which has seen an increase in solving power of more than six orders of magnitude in 20 years (with improvements in software having an even greater impact than the improvements in raw processing power that are described by "Moore's Law"). The lectures will show how these improvements, together with improved data access and automated business processes, are making optimization tools a more central part of enterprise management. An early contribution to these improvements was Bixby's incorporation of a number of ideas relating to software architecture, algorithms, and numerical analysis into the development of the CPLEX software, which led to the foundation of the company bearing its name.

The lectures honor the memory of D. R. Fulkerson, who was the Maxwell Upson Professor of Engineering in ORIE from 1971 until his death in 1976. Prior to coming to Cornell Fulkerson spent 20 years in the mathematics department at the Rand Corporation. He was one of the pioneers of Operations Research, a field that had been established only a few years before he received his Ph.D. from the University of Wisconsin in 1951.

Fulkerson's first published paper, with George Dantzig, solved a problem of scheduling cargo ships and is still commonly cited in courses as an example of the applicability of network optimization models. His second paper, with Dantzig and Selmer Johnson, introduced a construct known as cutting planes and set the stage for successful computational approaches to large-scale optimization problems in which the solution values are constrained to be whole numbers (integer programming). The authors solved a 49-city traveling salesman problem, a tour-de-force given the limitations of computing power in the 1950s. His third paper, the beginning of a stream of work with L. R. Ford, Jr. that laid the foundations of the theory of flows in networks, proved the fundamental theorem characterizing the maximum rate of flow through a network of capacity-constrained links in terms of the minimum capacity of a cut separating the source and sink of the flow.

Bixby's first lecture, "Solving Linear and Integer Programs: More than Moore," will take place at 4:30 p.m. on Monday, April 21, 2008. The second lecture, "Implementing Simplex Algorithms," will take place at 4:30 p.m. on Wednesday, April 23, 2008. The third lecture, "From Planning to Operations: The Ever-Shrinking Optimization Time Horizon", will take place at 3:30 p.m. on Friday, April 25, 2008. It is sponsored jointly by the Center for Applied Mathematics. All three lectures will be given in B17 Upson Hall.

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