Retired Professor
Department of Engineering Management, Information, and Systems
Contact
Phone:  2147683079 
Email:  helgason@lyle.smu.edu 
Educational Background
B.S., Iowa State University, 1962; M.S., University of Wisconsin, 1965; M.S., University of Colorado, 1973; M.S., Southern Methodist University, 1976; Ph.D., Southern Methodist University, 1980
About
B.S., Iowa State University, 1962; M.S., University of Wisconsin, 1965; M.S., University of Colorado, 1973; M.S., Southern Methodist University, 1976; Ph.D., Southern Methodist University, 1980Computational optimization, especially network flows; Computational geometry, especially identifying generators for convex hulls and cones; Also interested in computer algebra, economic analysis and missile routingBooks and Book Chapters

Algorithms for Network Programming, (with J. Kennington), John Wiley & Sons, (1980).

"Primal Simplex Algorithms for Minimum Cost Network Flows," (with J. Kennington), Chapter 2 in Handbook on Operations Research and Management Science Volume 7, Editors M. Ball, T. Magnanti, C. Monma, and G. Nemhauser, Elsevier Science B.V., NorthHolland, Amsterdam, (1995) 85133.

Interfaces in Computer Science and Operations Research: Advances in Metaheuristics, Optimization, and Stochastic Modeling Technologies (coeditor with R. Barr and J. Kennington), Kluwer Academic Publishers, Boston, (1997).

"Minimum Cost Network Flow Algorithms," (with J. Kennington), Chapter 6 in Handbook of Optimization in Telecommunications, Editors P. Pardalos and M. Resende, Kluwer Academic Publishers, Boston, (2006) 147162.
Refereed Publications

"A Matrix Method for Ordinary Differential Eigenvalue Problems," (with J. Gary), Journal of Computational Physics, 5(2), (1970), 169187.

"An Extension of FORTRAN Containing Finite Difference Operators," (with J. Gary), SOFTWARE: Practice and Experience, 2, (1972), 321336.

"An Efficient Procedure for Implementing a Dual Simplex Network Flow Algorithm," (with J. Kennington), AIEE Transactions, 9(1), (1977), 6368.

"A Product Form Representation of the Inverse of a Multicommodity Cycle Matrix," (with J. Kennington), Networks, 7(4), (1977), 297322. (Presented at ORSA/TIMS in San Francisco  1977.)

"Solving the Pipe Network Analysis Problem Using Optimization Techniques," (with M. Collins, L. Cooper, J. Kennington, and L. LeBlanc), Management Science, 24(7), (1978), 747760. (Invited paper at ORSA/TIMS in San Francisco  1977.)

"Primal Simplex Network Codes: StateoftheArt Implementation Technology," (with A. Ali, J. Kennington, and H. Lall), Networks, 8(4), (1978), 315340. (Invited paper at ORSA/TIMS in Atlanta  1977.)

"A New Storage Reduction Technique for the Solution of the Group Problem," (with J. Kennington), Naval Research Logistics Quarterly, 26(4), (1979), 681687. (Presented at ORSA/TIMS in New York  1978.)

"A Polynomially Bounded Algorithm for a Singly Constrained Quadratic Program," (with J. Kennington and H. Lall), Mathematical Programming, 18(3), (1980), 338343.

"Computational Comparison Among Three Multicommodity Network Flow Algorithms," (with A. Ali, J. Kennington, and H. Lall), Operations Research, 28(4), (1980), 9951000.

"Spike Swapping in Basis Reinversion," (with J. Kennington), Naval Research Logistics Quarterly, 27(4), (1980), 697701. (Presented at ORSA/TIMS in Milwaukee  1979.)

"Splitting the Bump in an Elimination Factorization," (with J. Kennington), Naval Research Logistics Quarterly, 29(1), (1982), 169178. (Presented at ORSA/TIMS in Washington, D.C.  1980.)

"Improved E_ciency of the FrankWolfe Algorithm," (with L. LeBlanc and D. Boyce), Transportation Science, 19(4), (1985), 445462. (Presented at ORSA/TIMS in Houston  1981.)

"The Frequency Assignment Problem: A Solution via Nonlinear Programming," (with J. Allen and J. Kennington), Naval Research Logistics, 34, (1987), 133139. (Presented at Mathematical Programming Symposium at MIT  August 1985.)

"A Generalization of Polyak's Convergence Result for Subgradient Optimization," (with E. Allen, J. Kennington, and B. Shetty), Mathematical Programming, 37, (1987), 309317.

"An Air Force Logistics Decision Support System Using Multicommodity Network Models," (with A. Ali and J. Kennington), The Annals of the Society of Logistics Engineers, 1(2), (1987), 93104. (Presented at ORSA/TIMS in Washington, D.C.  1980.)

"A Parallelization of the Simplex Method," (with J. Kennington and H. Zaki), Annals of Operations Research, 14, (1988), 1740.

"The Supressed Basis Method," (with B. Patty), Annals of Operations Research, 20, (1989), 233248.

"Minimal Spanning Trees: A Computational Investigation of Parallel Algorithms," (with R. Barr and J. Kennington), Parallel Computing, 12, (1989), 4552.

"Preprocessing Schemes and a Solution Method for the Convex Hull Problem in Multidimensional Space," (with J. Dula and B. Hickman), in Computer Science and Operations Research: New Developments in Their Interfaces, Pergamon Press, Oxford, England, (1992), 5970.

"The OnetoOne ShortestPath Problem: An Empirical Analysis with the TwoTree Dijkstra Algorithm," (with J. Kennington and B. Stewart), Computational Optimization and Applications, 1, (1993), 4775.

"A Direct Simplex Algorithm for Network Flow Problems with Convex Piecewise Linear Costs," (with R. Murthy), Optimization Methods and Software, 4, (1994), 191207.

"A Nearly Asynchronous Parallel LPbased Algorithm for the Convex Hull Problem in Multidimensional Space," (with J. Dula and N. Venugopal), in The Impact of Emerging Technology On Computer Science and Operations Research, S. Nash and A. Sofer, eds., Kluwer Academic Publishers, Boston, (1995), 89102.

"A New Procedure for Identifying the Frame of the Convex Hull of a Finite Collection of Points in Multidimensional Space," (with J. Dula), European Journal of Operational Research, 92, (1996), 352367.

"An Algorithm for Identifying the Frame of a Pointed Finite Conical Hull," (with J. Dula and N. Venugopal), INFORMS Journal on Computing, 10, (1998), 323330.

"Cruise Missle Mission Planning: A Heuristic Algorithm for Automatic Path Generation," (with J. Kennington and K. Lewis), Journal of Heuristics, 7, (2001), 473494.

"An EqualOpportunityLoss Model for Fairnessbased MPLS Network Design," (with R. Barr, S. Jarrar, and M. Petkova), Proceedings of the 2005 International Conference on Telecommunications Systems  Modeling and Analysis (ICTSMA2005), (2005), 96110.