Satellite Communications Engineer
Expert Witness No. 121
New Jersey
Network Architecture, Design & Analysis Performance Analysis Broadband Wireless Satellite Networks
Professional Experience
A. T. Kearney, January 99 - Present
DLT Consultant, London, England
| • | Participate on the second phase of a technical due diligence team assessing the satellite and ground systems for a global mobile satellite system.
| • | Quantify launch failure scenarios.
AT&T Laboratories, October 98 – December 98
DLT Consultant, Holmdel, NJ
| • | Define Internet and Intranet measurement methodologies to assess end-user perceived performance.
Software Technologies, Inc., June 98 - Present
DLT Consultant, Melbourne, FL
| • | Perform scalability analysis of the system design for a ground station satellite controller.
Motorola Satellite Communications, June 98 - July 98
IQ Tech Consultant, Chandler, AZ
| • | Began performance assessment of access schemes for data services for a next generation mobile satellite system
A. T. Kearney,January 98 - March 98
IQ Tech Consultant, London, England
| • | Participate on a technical due diligence team assessing the satellite and ground systems for a global mobile satellite system.
| • | Assess cost models used in the Satellite System Business Plan.
| • | Quantify launch failure scenarios.
Bell Communications Research, September 97 - December 97
IQ Tech Consultant, Morristown, NJ
| • | Provide algorithms and custom software for approximating long-range dependent data traffic (e.g., IP or broadband) with a Markovian Arrival Process.
| • | Provide algorithms and custom software for computing appropriate performance measures to be used for engineering the network.
Lockheed Martin Telecommunications, September 96- August 97
IQ Tech Consultant, Sunnyvale, CA
| • | General performance analysis for theAstrolink broadband satellite system.
| • | Assessed the loss of efficiency of imposing various constraints on the Demand Assignment Multiple Access (DAMA) algorithms.
| • | Buffer sizing studies.
AT&T Laboratories, September 96 - April 97
IQ Tech Consultant, Holmdel, NJ
| • | Began assessment of internet telephony as both a threat and an opportunity to AT&T long distance revenues.
| • | Prepared an internal management presentation on Choices in Packet Telephony.
AirNet Communications, Inc., June 95 - June 96
IQ Tech Consultant, Melbourne, FL
| • | Provide continuing consulting services for performance analysis and architecture for a start-up wireless company.
| • | Supervised in-house development of a system-level simulation.
| • | Designed the resource allocation algorithm for a PCS1900 Base Station Subsystem.
| • | IQ Tech staff completed development of the call processing (architecture design, implementation and testing) of a PCS1900 Base Station Controller in 15 months.
| • | Presented the paper "Supporting ATM on Low-Earth Orbit Satellite Systems" at the ITC Specialists Seminar in Amsterdam.
Motorola, Inc., Sept. 94 - June 95
IQ Tech Consultant, Chandler, AZ
| • | General performance analysis for theIridium™ Low-Earth Orbit satellite system.
| • | Continued development of a crucial resource allocation algorithm which operates in real time on-board the satellite vehicle.
| • | Developed risk models to determine insurance strategies for coping with potentially unreliable launch vehicles in the initial deployment of theIridium™ system.
| • | Recruited and established a Network Integrity Support Team to focus on performance aspects of theIridium™ system.
Motorola, Inc., April-Sept. 1994
Member of Technical Staff (GS-13),Chandler, AZ
| • | General performance analysis for theIridium™ Low-Earth Orbit satellite system.
| • | Designed a real-time resource allocation algorithm to operate on-board the satellite vehicle.This algorithm avoided a costly hardware redesign saving more than $30M.
AT&T Bell Laboratories,1981-1994
Distinguished Member of Technical Staff, Holmdel, NJ
| • | Broadband ISDN/ATM
| • | defined overall control architecture, incorporating end-to-end flow control, traffic shaping capabilities and higher layer control functions; portions have been incorporated into international standards
| • | using exact and approximate models, quantified the multiplexing gain for a large number of bursty sources and the impact on engineering of ATM networks
| • | using exact models, demonstrated that predictions based on the popular notions of "effective bandwidth" could be arbitrarily poor; proposed more accurate approximations
| • | derived and solved analytically tractable models for quantifying the effectiveness of the "throughput-burstiness filter" and selective cell discard mechanisms for congestion control
| • | using models and analysis, formulated specific recommendations for switched virtual circuit call acceptance/denial algorithms and for bandwidth-on-demand negotiation algorithm
| • | Algorithmic solutions to stochastic models, queuing theory, and applied probability
| • | developed algorithms for numerically computing an arbitrary number of moments as well as the exact asymptotic behavior of a distribution function from its transform
| • | contributed to the development of algorithms for numerically inverting multidimensional Laplace-Stieltjes transforms and/or probability generating functions
| • | drastically simplified analysis and algorithms for a large class of complex queuing models (BMAP/G/1queue) which also include multiplexed, highly-correlated arrival streams
| • | derived exact solutions and numerical algorithms for computing the transient performance measures of the above class of models; this framework allows new insights into the problems of overload control and call acceptance algorithms for broadband networks
| • | combined transform/eigen-analysis approach with the matrix-geometric method to solve important class of voice and data queuing models
| • | introduced the, now popular, Markovian Arrival Process (MAP) as a versatile and tractable class which includes both renewal and non-renewal point processes
| • | solved the queue with vacations using above model; generalized known factorization results to the non-renewal case and obtained new factorization results
| • | derived an enormously improved approach for solving the nonlinear matrix functional equation arising in the matrix analytic solution to phase-type queues
| • | provided the first general proof that the key transform matrix involved in solving stochastic models of the "M/G/1 Type" was the unique minimal solution to a non-linear matrix- functional equation
| • | Variable-bit-rate video
| • | developed Markov renewal model for sizing leaky bucket parameters for call setup algorithms
| • | defined two novel measures of goodness-of-fit of model to data
| • | Packetized voice and data
| • | derived powerful, and widely used, methodology for approximating superpositions of complicated arrival stream (such as packetized voice) by simpler, tractable processes (e.g., Markov modulated Poisson processes)
| • | derived analytic model of bit-dropping in packetized voice which demonstrated (and explained why) a Poisson process was an accurate model for predicting performance
| • | Wideband packet technology
| • | derived and solved (using state-of-the-art solution techniques) an analytic model of the LAPD protocol incorporating timers, retransmissions, polls, etc., in conjunction with a variety of end-terminal window adaptation procedures and network throughput enforcement controls
| • | LAPD frame relay
| • | assisted in design of terminal adapters for frame-relay networks by identifying performance degradations resulting from interactions of pipelining and protocol windowing
| • | Packet switching
| • | derived matrix-analytic performance assessment methodology for a synchronous self-routing packet switching fabric which quantified impact of traffic burstiness and effects of switch parameters
| • | Digital switch performance
| • | responsible for performance of new modules required to support ISDN on existing digital switches
| • | provided developers with a variety of performance inputs which affected microprocessor selections, buffer sizing, capacity planning, etc.
| • | Cellular phone technology
| • | designed and analyzed a system level overload control; potential system throughput degradation under overload was identified; proposed a simple fix which was implemented in system
Education
Ph.D. Operations Research, University of Delaware, Newark, DE, 1981
| • | Dissertation analyzed stop-and-wait retransmission protocol for data integrity where the error environment is highly correlated; was published as a monograph in the Research Notes in Mathematics series of Pitman Books Limited, London, 1982
| • | Dissertation contained the first general proof that the key transform matrix involved in solving stochastic models of the "M/G/1 Type" was the unique minimal solution to a non-linear matrix functional equation
| • | Completed over 80 graduate credits in Mathematics and Operations Research with a GPA of 3.96/4.0
M.S. Statistics, University of Delaware, Newark, DE, 1978
| • | Thesis entitled Numerical Methods for a Wide Class of Markov Chains Arising in Queuing Theory
B.S. Mathematics, Towson State University, Towson, MD, 1976
Awards and Honors
| • | Mary Hudson Scarborough Award for Excellence in Mathematics, Towson State University, 1976
| • | Allan P. Colburn Prize for best dissertation in Engineering and Mathematical Sciences, University of Delaware, 1982
| • | Subject of biographical record in Who’s Who in Frontier Science and Technology, and American Men and Women in Science, 1984
| • | Co-recipient of IEEE Communications Society Stephen O. Rice Prize Paper Award in the field of Communication Theory (with H. Heffes), 1986
| • | Promoted to Distinguished Member of Technical Staff, AT&T Bell Laboratories, 1987
| • | Co-recipient of an Honorable Mention for the 1998 INFORMS Frederick W. Lanchester Prize for the best published work in Operations Research and the Management Sciences, 1998
Teaching Experience
Stevens Institute of Technology, 1991-93
Adjunct Professor, Computer Science, Hoboken, NJ
| • | Taught graduate level courses in Probability and Stochastic Processes
Patents
| • | Novel congestion control techniques for Broadband ISDN/ATM involving traffic monitoring and tagging as well as selective cell discard during congestion resulted in two patent awards (with A.E.Eckberg, D.T. Luan, and T.J. Schonfeld).
| • | The ideas behind these patents have been incorporated into the international standards for ATM switches.
| • | The patents are now the property of Lucent Technologies.
Professional Activities
| • | over fifty papers published in scientific journals
| • | former Associate Editor forQueuing Systems
| • | reviewer for National Science Foundation proposals and many scientific journals
| • | frequent speaker at international conferences and universities
| • | Member of IEEE, INFORMS, ACM
Publications
List of over 50 Available upon request
