Daniel P. Heyman

June 18, 1939

Brief Biography

Heyman APS Chair Portrait

Daniel P. Heyman is a telecommunications operations researcher who has made significant contributions to characterizing data traffic, queueing theory, Markov chain computations, and internet performance modeling. Heyman majored in industrial engineering at Rensselaer Polytechnic Institute prior to pursuing a Masters of Industrial Engineering from Syracuse University. In graduate school, Heyman’s scholastic emphasis was in operations research as he went on to receive a PhD in the subject from the University of California, Berkeley in 1966.

Early in his career, Heyman’s research primarily focused on queueing theory and its application. Heyman was part of the Operations Research Department of Bell Laboratories, primarily working on queueing problems. This involved publishing papers with Shaler Stidham and fellow Bell Labs employee Ward Whitt.There, he made theoretical contributions to the “T” policy for control of queues, conservation laws for queues, the analysis of non-stationary queues, and models of computer systems. In the 1970s, his research began to incorporate inventory theory, focusing on inventory models with returned items. Starting in 1974, Heyman began concurrently teaching graduate courses at Yale University’s Department of Administrative Sciences. As a instructor, he advised one PhD dissertation in operations research and one BS thesis in applied mathematics.

By 1990, Heyman had begun to move away from queueing theory. He had left Bell Labs for the Applied Probability Group of Bellcore in 1984 and had started research on communication protocol performance modeling, Markov Chains, and simulation. At Bellcore, Heyman dealt with a variety of topics in stochastic operations research. His application work included the design of a network management system for an emergency national telephone system and capacity planning for broadband services. In the early 1990s, he began working on coded video traffic source modeling, publishing articles on VBR video-conferences and statistical analysis in teleconference traffic.

In the early 1980s, Heyman co-authored a two-volume set on stochastic modeling with Matthew J. Sobel. The first volume, published in 1982, was a finalist for the Frederick W. Lanchester Prize for best publication in operations research. It explores the central facts and ideas of stochastic processes, illustrating their use in models based on applied and theoretical investigations. The second volume, published in 1984, focuses on stochastic optimization.

Heyman left Bellcore for the Network Design and Performance Analysis Department of AT&T Labs, where he remained until his 2003 retirement. It was here where he made his fundamental contributions to statistical modeling of data traffic. Heyman’s work included the modeling of data movement in order to develop practical methods to predict network performance and the design of overload control algorithms for packet networks. Three patents came from this work.

Heyman has been a dedicated member of the professional operations research and management sciences community. He is a past chairman the Applied Probability Society and the ORSA/INFORMS Technical Section on Telecommunications and has served on the selection committees for a number of prizes. He was also a member of the ORSA Council. In 2006, Heyman was elected a Fellow of the Institute for Operations Research and the Management Sciences.


Rensselaer Polytechnic Institute, BMgtE 1960

Syracuse University, MIE 1962

University of California, Berkeley, PhD 1966 (Mathematics Genealogy


Academic Affiliations
Non-Academic Affiliations

Key Interests in OR/MS

Application Areas

Memoirs and Autobiographies


Awards and Honors

Institute for Operations Research and the Management Sciences Fellow 2006

Professional Service

ORSA Technical Section on Telecommunications, Chair 1994

ORSA Council, 1984-1987

Applied Probability Society, Chair 1978-1979 

Selected Publications

Heyman D. P. (1968) Optimal operating policies for M/G/1 queuing systems. Operations Research, 16(2): 362-382.

Heyman D. P. (1978) Return policies for an inventory system with positive and negative demands. Naval Research Logistics Quarterly, 25(4): 581-596.

Heyman D. P. & Sobel M. J. (1982) Stochastic Models in Operations Research, volume 1. McGraw Hill: New York.

Heyman D. P. & Sobel M. J. (1984) Stochastic Models in Operations Research, volume 2. McGraw Hill: New York. 

Gassman W. K., Heyman D. P. & Taksar M. I. (1985) Regenerative analysis and steady state distributions for Markov chains. Operations Research, 33(5): 1107-1116.

Heyman D. P., Lakshman T. V., & Tabatabai A. (1992) Statistical analysis and simulation study of video teleconference traffic in ATM networks. IEEE Transactions on Circuits and Systems for Video Technology, 2(1): 49-59.

Elwalid A., Heyman D. P. Lakshman T. V., Mitra D., & Weiss A. (1995) Fundamental bounds and approximations for ATM multiplexers with applications to video teleconferencing. IEEE Journal on Selected Areas in Communications, 13(6): 1004-1016.

Heyman D. P. & Lakshman T. V. (1996) Source models for VBR broadcast-video traffic. IEEE/ACM Transactions on Networking, 4(1): 40-48.

Heyman D. P. & Lakshman T. V. (1996) What are the implications of long-range dependence for VBR-video traffic engineering?. IEEE/ACM Transactions on Networking, 4(3): 301-317.

Heyman D. P., Lakshman T. V., & Neidhardt A. L. (1997) A new method for analysing feedback-based protocols with applications to engineering web traffic over the internet. SIGMETRICS, 25(1): 24-38.

Heyman D. P. (2005) Sizing backbone internet links. Operations Research, 53(4): 575-585.