Ph.D. Theoretical Atomic Physics, University of Connecticut, 1965
Physics, Brandeis University, 1956-1958
B.M.E Mechanical Engineering, City College of New York, 1956
Personal Information
Post-Doctoral Research Fellow, NRC-NSF, National Bureau of Standards, USA, 1965-1966
Research Associate, Royal Holloway College, University of London, UK, 1966-1968
Assistant, Associate, Full Professor, Department of Computer Science,
University of Nebraska (Lincoln), 1968-1971-1976-1987.
Professor Lipsky teaches courses in Queueing Theory, Probabilistic Methods in
Digital Systems, Probabilistic Performance of Computer Systems, and Automata
Theory. He has a broad interest in atomic physics and various aspects of
computer science including numerical analysis and computing theory. His
specialty is computer network performance with special emphasis on Linear
Algebraic Queueing Theory (LAQT).
Research Interests:
Parallel and Distributed Computer Systems Performance Modeling
Applications of Queueing Theory to Problems in Computer Science
Theoretical Foundations for Linear Algebraic Queueing Theory
Publications and Reviewed Conference Proceedings Since 1989
``Modelling Parallel and Distributed Systems With Finite Workloads,"
(with Ahmed M. Mohamed and Reda Ammar),
Journal of Performance Evaluation, Volume 60, , May 2005, pp 303-325. (pdf 481Kb)
``The Effect of Different Failure recovery Procedures On the Distribution
Of Task Completion Times." (with Robert Sheahan and Pierre Fiorini)
DPDNS05 Denver CO, April 2005 (dpdns05.ps 225K)
``On the Relationship Between Packet Size and Router Performance for
Heavy-Tailed Traffic." (with Imad Antonios),
The Third IEEE International Symposium on Network
Computing and Applications (NCA04), Boston, MA, Sept, 2004 (nca04.pdf 600K)
``Analytic Performance Analysis for Parallel and Distributed Systems with
Non-exponential Service Centers,"
(with Ahmed M. Mohamed and Reda Ammar),
17th ISCA International Conference on
Parallel and Distributed Computing Systems (PDCS-04),
San Francisco, CA, Sept 2004.
``Transient Performance Model for Parallel and Distributed Systems,"
(with Ahmed M. Mohamed and Reda Ammar),
Proceedings of the 10th IEEE International Conference on Parallel and
distributed Systems (ICPADS-04), Newport Beach, CA, July 7-10, 2004. (pdf 239Kb)
``Modelling Parallel and Distributed Systems with Finite Workloads,"
(with Ahmed M. Mohamed and Reda Ammar),
Proceedings of the 9th IEEE Workshop on Fault-Tolerant Parallel,
Distributed and Network-Centric Systems (FTPDS-04), Santa Fe, NM,
April 26-30 2004 (pdf 255Kb)
``Efficient Resource Allocation for Parallel and Distributed Systems,"
(with Ahmed M. Mohamed and Reda Ammar),
WSEAS Transactions on Computers, Vol. 3, No. 5,
pp. 1214-1219, April, 2004.
(Also presented to the 4th WSEAS International Conference on Information
Science, Communication and Applications (ISA-04), Miami, FL, April 2004) (pdf 186Kb)
``Energy Levels and Classifications of Triply Excited States of N^4+, O^5+,
F^6+ and Ne^7+,'' (with M. J. Conneely),
Atomic Data and Nuclear Data Tables 86, January 2004
``Transient Model for Jackson Networks and its Approximation," (with
Ahmed M. Mohamed and Reda Ammar), 7th International Conference
on Principles of Distributed Systems (OPODIS03), December
10-13 2003, La Martinique, France. (PDF 229Kb)
``Efficient data Allocation for a Cluster of Workstations,"
(with Ahmed M. Mohamed and Reda Ammar)
16th International Conference on Parallel and Distributed
Computing Systems (PDCS 2003),
Reno, NV, August 10-13, 2003. (PDF 83Kb)
``Availability Versus Performance," (with Pierre Fiorini), Computing
International Scientific Journal, Vol 2, No. 1, June, 2003.
``Availability Versus Performance," (with Pierre Fiorini),
The 2003 International Conference on Parallel and Distributed
Processing Techniques and Applications, (IDAACS-2003) pp.1352-1357,
Las Vegas, NV, June 23-26, 2003.
``Analytic Performance Model of P Fault-Prone Parallel Processors
Running N Deterministically Distributed Tasks," (with Saira Kazmi),
The 2003 International Conference on Parallel and Distributed
Processing Techniques and Applications (IDAACS-2003), pp.1339-1345,
Las Vegas, NV, June 23-26, 2003.
``Performance Model for a Cluster of Workstations," (with Ahmed M. Mohamed
and Reda A. Ammar), The 4th International Conference on Communications in
Computing (CIC-2003), pp. 227-233, Las Vegas, NV, June 23-26, 2003. (PDF 67Kb)
``A Matrix Analytic Approach to Assess the Performance of Computing Systems
Subject to Failure and Repair with non-Exponential Task Time Distributions,"
(with Robert W. Rowen and Pierre M. Fiorini), Proceedings of The
2003 International Conference on Parallel and Distributed Processing Techniques
and Applications (IDAACS-2003), pp 1363-1369, Las Vegas, NV, June 23-26, 2003.
``A Performance Model and Analysis of Heterogeneous Traffic with
Heavy Tails," (with Imad Antonios), The 2nd
IEEE International Symposium on Network Computing and
Applications (NCA03), pp.367-373, Cambridge, MA, April 2003.
``An Analytic Approach to Assess the Performability of Parallel and
Distributed Systems," (with P. M. Fiorini and Colin. Campbell)
15th International Conference on Parallel and Distributed
Computing Systems (PDCS 2002),
Lousville, Ky, September 19-21, 2002.
``Theoretical and Experimental Results of Processing N Tasks in the
Presence of Processor Failures," (with Gehan Weeransinghe),
15th International Conference on Parallel and Distributed
Computing Systems (PDCS 2002),
Lousville, Ky, September 19-21, 2002. (postscript 100Kb)
``Energy Levels and Classifications of Triply Excited States of Li, Be+, B++ and
C+++,'' (with M. J. Conneely),
Atomic Data and Nuclear Data Tables, September 2002 (postscript 336Kb)
``A Performance Model for End-to-End User Delay in Telecommunications Systems
With Self-Similar Traffic," (with Imad Antonios),
2002 International Symposium on Performance Evaluation of Computer and
Telecommunication Systems, (SPECTS 2002), San Diego, CA,
July 15-19, 2002.
``A Generalized Analytic Performance Model Of Distributed Systems That Perform
N Tasks Using P Fault-Prone Processors,"
(with Gehan Weeransinghe and
Imad Antonios), FTPDS-02, Fort Lauderdale, Fla, April 2002. (postscript 458kb)
``A Distributed Fault-Tolerant Asynchronous Algorithm for Performing N
Tasks,"
(with Gehan Weerasinghe), Special issue of INFORMATION: An International
Journal, pp. 513-527, Vol.4, No.4 ,2001, (extended version of our paper in
ISCA 16th International Conference on Computers and Their Applications,
Seattle, Washington, USA, March 28-30, 2001). (postscript 266Kb)
``Comparison of The Analytic N-Burst Model with Other Approximations to
Self-similar Telecommunications Traffic,'' (with Hans-Peter Schwefel, Michael
Greiner and Manfred Jobmann), IEEE NCA_01 Symp. on Network
Computing, Cambridge, MA. 10-12 October 2001 (rescheduled for February 11-13
2002), (preliminary version given at the 10th INFORMS Applied Probability
Conference, Ulm, Germany, July 26-28 1999.) (postscript gzip 139Kb)
``An Analytic Performance Model Of Parallel Systems That Perform N tasks Using
P Processors That Can Fail,'' (with Gehan Weerasinghe and Imad Antonios),
IEEE NCA_01 Symp. on Network Computing, Cambridge, MA. 10-12 October 2001
(rescheduled for February 11-13 2002). (postscript gzip 139Kb)
``On the Necessity of Transient Performance Analysis in Telecommunication
Networks," (with Hans Schwefel and Manfred Jobmann),
17th International Teletraffic Congress (ITC17),
Salvador da Bahia, Brazil, September 24-28 2001 (postscript gzip 383Kb)
``A Fault-Tolerant Asynchronous Algorithm for Performing N Tasks on a Cluster"
(with Gehan Weerasinghe), ISCA 16th International Conference
on Computers and Their Applications , Seattle, Washington, USA,
March 28-30, 2001.
``Triply Excited States of the Lithium Isoelectronic Sequence: Z=3 to 10,"
(with Micheal J. Conneely), 2000 DAMOP , Storrs CT, June 14-17, 2000.
``Impact of Aggregated, Self-Similar ON/OFF traffic on Delay in Stationary
Queueing Models (Extended Version)," (with Hans-Peter Schwefel),
PERFORMANCE EVALUATION , May 2000.
``Simulations With Heavy-Tailed Workloads," Chapter 3 of
"Self-Similar Network Traffic and Performance Evaluation",
(with M. E. Crovella), Wiley/Wiley-Interscience, 2000.
(See crovell@cs.bu.edu)
``Hollow States of Lithium,'' (with Micheal J. Conneely),
PHYSICAL REVIEW A, 61 , February 2000. (postscript gzip 168Kb)
``Impact of Aggregated Self-Similar ON/OFF Traffic on Delay in Stationary Queueing
Models," (with Hans-Peter Schwefel), Proceedings of SPIE, Vol.3841 (Performance and
Control of Network Systems III), Boston, USA, September 20, 21 1999. (Hans-Peter Schwefel)
``Analytic Models of Transient Behavior for Servers with Self-Similar Traffic,"
(with Hans-Peter Schwefel),
10th INFORMS Applied Probability Conference, Ulm, Germany, July 26-28 1999
``Performance Results For Models of Traffic in Telecommunication Systems, Based on
Multiple ON-OFF Sources With Self-Similar Behavior," (with Hans-Peter Schwefel),
Teletraffic Engineering in a Competitive world, Vol 3A, P.Key and D. Smith,
Eds., pp55-66, Elsevier Science B.V., 1999, also
Proceedings for the 16th International Teletraffic Congress,
Edinburgh, Scotland, June 7-11, 1999 (postscript gzip 153Kb)
``Buffer Size Issues in the Presence of Self-Similar Traffic,"
(with Hans-Peter Schwefel), Third IFIP workshop on Traffic Management and Design
of ATM Networks, London, April 26-27 1999. (postscript gzip 50KB)
``Analytic Model of Performance in Telecommunication Systems, Based on
ON-OFF Traffic Sources With Self-Similar Behavior,"
(with Pierre Fiorini and And Hans-Peter Schwefel), 7th International Conference on
Telecommunication Systems, Nashville, TN, March 18-21, 1999 (postscript gzip 170Kb)
``The Importance of Power-Tail Distributions for Modeling Queueing Systems,"
(with Manfred Jobmann and Michael Greiner),
Operations Research, Vol 47, No. 2, (March-April 1999). (postscript gzip 152kb)
``A Heavy-tailed ON/OFF Source Model with Applications to Network Capacity
Planning,'' (with P. M. Fiorini and Yiping Ding), PDCS'98, September 1998 (postscript gzip 104Kb)
``Long-Lasting Transient Conditions in Simulations with Heavy-Tailed
Workloads, (with Mark Crovella), Proceedings of the 1997 Winter
Simulation Conference (WSC-97), December 1997. (postscript gzip 173kb)
(See also crovell@cs.bu.edu)
``Consequence of Ignoring Self-Similar Data Traffic In Communications
Modeling", (with Pierre Fiorini and Mark Crovella),
Tenth International Conference on Parallel and Distributed Computing
(PDCS-97), New Orleans, LA, October 1997. (Related paper, postscript gzip 98Kb)
``Comparison of Buffer Usage Utilizing Multiple Servers in Network Systems
With Power-Tail Distributions," [Invited], (with John Hatem and Pierre
Fiorini), INFORMS97, Boston MA, 30 June-2 July 1997. (postscript gzip 94Kb)
``Tractable Queueing Paradigms for Modeling Telecommunications Systems
with Self-similar Traffic," [Invited], (with Pierre Fiorini),
INFORMS97, Boston MA, 30 June-2 July 1997.
``Buffer Problems in Telecommunications Networks," (with John E. Hatem),
Fifth International Conference on Telecommunication Systems,
Nashville, TN, March, 1997. (postscript gzip 82Kb)
``Modelling Telecommunications Systems That Have Power-tail (Bursty, Chaotic,
Heavy-Tail, Self-Similar, etc) Traffic," Invited Speaker, 22nd International
Conference for the Resource management and Performance Evaluation of
Computing Systems (CMG96), San Diego CA, December 1996.
``On The Performance of Parallel Computers: Order Statistics and Amdahl's
Law, and Their Applications," (with Tao Zhang and Yiping Ding)
22nd International Conference for the Resource Management and Performance
Evaluation of Computing Systems (CMG96),
San Diego CA, December 1996.
``On The Performance of Parallel Computers: Order Statistics and Amdahl's
Law," (with Tao Zhang and Seonglim Kang), International Journal Of
Computers And Their Applications, Vol 3, #2, August 1996. (postscript gzip 76Kb)
``Steady-State Solution for Join-the-Shortest-Queue Policy in General Server
Systems," (with Seonglim Kang), IASTED - International Conference on
Modeling and Simulation, Pittsburgh, PA, May 1996. (postscript gzip 82Kb)
``Configuration Mixings in Triply-Excited states in 3-Electron Systems,"
(with Micheal J. Conneely), XIX ICPEAC,
Vancouver, BC, Canada, July 1995.
``Load Sharing in Dynamic Environments,'' (with Seonglim Kang)
IASTED Secretariat PDCS'94 (IASM), Washington, D.C., October 1994.
``A Comparison of Three Switching Schemes In Isotropic Networks With Noisy
Channels,'' (with Aby Tehranipour), IEEE Transactions On
Communications, 41, pp. 782-792, (May 1993).
``A Model For The Probability Distribution of Medical Expenses''
(with Walter Lowrie), Proceedings of Conference Of Actuaries
In Public Practice, (1993).
``Three-Electron Systems With Inner Shell Vacancies,'' (with Micheal J.
Conneely and Arnold Russek), PHYSICAL REVIEW A, 46, 7,
pp. 4012-4025 (October 1992).
``The Effect of Power-Tail Distributions on the Behavior of Time Sharing
Computer Systems,'' (with Sharad Garg and Maryann Robbert), 1992 ACM
SIGAPP Symposium on Applied Computing, Kansas City, MO, March, 1992.
``The Generalized M/G/C//N-Queue as a Model for Time-Sharing
Systems,'' (with Aby Tehranipour), ACM-IEEE Joint Symposium on Applied
Computing, Fayetteville, AR, April, 1990.
``Signal Probabilities in AND-OR Trees,'' (with Sharad Seth),
IEEE - Transactions On Computers, V-38, 11, pp. 1558-1563,
November 1989.
``A Comparative Study of Switching Schemes in Isotropic Networks,''
(with Aby Tehranipour and I. Ieong), IEEE International
Conference on Systems Engineering, August 1989.
``Residual Lifetimes as a Function of Queue Length for M/G/1//N Loops,''
(with Aby Tehranipour and Appie van de Liefvoort), Joint ACM-IEEE
Workshop on Applied Computing '89, Stillwater, Oklahoma, March 1989.
Technical reports and Works in Progress
``Dynamic resource Allocation of Computer Clusters With Probabilistic Workloads,"
(with Robert Sheahan, Marwan Sleiman and Pierre Fiorini),
Submitted to the NCA05. Cambridge MA, July 2005 (postscript 150Kb)
``Using Residual Times to Meet Deadlines in M/G/1 Queues,"
(with Sarah Tasneem, Reda Ammar and Howard Sholl),
Submitted to the NCA05. Cambridge MA, July 2005 (pdf 195Kb)
``Transient Model for Jackson Networks and its Application in Cluster Computing,"
(with Ahmed M. Mohamed and Reda Ammar),
Submitted to the Journal of Cluster Computing.
``Performance Analysis of Distributed Systems that
Perform N Tasks using P Fault-prone Processors, Without Repair,"
(with Gehan Weerasinghe), Technical Report, CSE/BRC July 2002. (postscript gzip 206Kb)
``How To Model Telecommunications (and Other) Systems Where Self-Similar
(Power-Tail) Behavior is Observed: (Background Review and Research Proposal),''
(with Michael Greiner, Mark Crovella, Wolfgang Klinger, Manfred Jobmann, Pierre Fiorini, and
Hans-Peter Schwefel), Technical Report, CSE/BRC May, 1997. (postscript gzip 223Kb)
``Hypothesis Testing Using The `Chi-Squared' Test,'' Class Notes, 1996 (postscript gzip 54Kb)
``Auto-Correlation of Lag-k For Customers Departing From Semi-Markov
Processes,'' (with Pierre Fiorini, Wen-Jung Hsin and Appie van de
Liefvoort), Technical Report, TUM, February 1995, (postscript gzip 470Kb)
``Transformation of the Kronecker Product of Identical Servers To A
Reduced Product Space,'' (with Appie van de Liefvoort),
Technical Report, TUM, December 1994, (postscript gzip 50Kb)
``A Comparison of Individual Shorter-Queue Selection With Globally More
Optimal Systems: An Application of LAQT; (with Seonglim Kang,
Tao Zhang and Brian Mackay), Technical Report BRC/CSE-TR-93-12 (1993). (postscript gzip 113Kb)
``N-Burst Processes as Analytic Models of Self-Similar Traffic in
Telecommunication Systems, I-Background, and II-Specific System Models and
Analytic Results,'' (with Hans-Peter Schwefel), In progress,
(With Technical University, Munich; Sponsored by Deutche Telecom)
Students' Theses
``Performance Based Cluster Architecture: Analytic Modelling and
Analysis," by Ahmed Mostafa Abdel-Rahman Mohamed, PhD, Department
of Computer Science and Engineering, University of Connecticut, June 2004. (thesis.ahmed.pdf 1703Kb)
``Performance Modelling and Experimental Evaluation of Systems That Perform
N Tasks Using P Fault-prone Processors in Parallel," by
Don Moses Gehan Weerinsinghe, PhD, Department of Computer Science and
Engineering, University of Connecticut, August 2002. (postscript gzip 2500Kb)
``Performance Analysis of Intermediate Systems Serving Aggregated ON/OFF Traffic with
Long-Range Dependent Properties,'' by Hans-Peter Schwefel, School
of Informatics, Technical University, Munich, Germany, September 2000. Hans-Peter Schwefel
``Comparison Of Buffer Usage Utilizing Single And Multiple Servers In
Network Systems With Power-tail Distributions.'' by John Edward Hatem,
PhD, Department of Computer
Science, University of Connecticut, December 1997. (postscript gzip 194kb)
``On the Convergence of Sums of Power-Tail Samples To Their $\alpha$-Stable
Distributions,'' by Wolfgang M. Klinger, MS, Department of Computer Science,
University of Connecticut, August 1997. (postscript gzip 212Kb) (scape.ps Hyp 593Kb)
``Modelling of Packet Arrivals Using Markov Modulated Poisson Processes With
Power-Tail Distributions,'' by Hans-Peter Schwefel, Diplomarbeit,
Faculty for Informatics, Technical University, Munich, Germany, September 1997. (postscript gzip 615Kb),
``Modeling Telecommunication Systems with Self-Similar Data Traffic," by
Pierre M. Fiorini, PhD, Department of Computer Science, University of
Connecticut, May 1998, (postscript gzip 280Kb)
Selected Recent Colloquia
"Comparison of Switching Schemes in Noisy Packet_Switching Networks,"
Computer Science and Telecommunications, University of Missouri-Kansas City,
13 September 1994.
"Dynamic scheduling of Queues," Department of Computer Science, University of
Nebraska, 22 September 1994.
``Queueing Theory in Computer Science," Department of Computer Science,
Regensburg Fachhochschule, Regensburg, Germany, 12 January 1995
``Power-Tail Distributions and Their Significance in the Behavior of
Computer and Telecommunications Systems," Dipartimento di Ingegneria
Elettronica, Universita' Degli Studi Di Napoli ``Federico II,"
Naples, Italy, 25 January 1995
``Power-Tail Distributions and Their Significance in the Behavior of
Computer and Telecommunications Systems," Department of Systems and
Networks, Siemens Corporation, München, Germany, 23 February 1995
``Power-Tail Distributions and Their Significance in the Behavior of
Computer and Telecommunications Systems," Applied Probability Group,
Dublin Institute for Advanced Studies, Dublin, Ireland, 15 April 1995.
``Power-Tail Distributions and Their Significance in the Behavior of
Computer and Telecommunications Systems,"Facultät Für Informatik,
Universät Der Bundeswehr München, München, Germany, 5
May 1995
``Power-Tail Distributions and Their Significance in the Behavior of
Computer and Telecommunications Systems," Department of Computer Science
and Engineering, University of Connecticut, Storrs, CT, 13 October 1995.
``Power-Tail Distributions and Their Significance in the Behavior of
Computer and Telecommunications Systems," Department of Electrical, Computer,
and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY, 1
February 1996.
``Power-Tail Renewal Processes as Models for `Self-Similar' Arrival Processes,
and Their Significance for Telecommunications Systems" Department of Computer
Science, Boston University, Boston, MA, 16 October 1996.
``Power-Tail Renewal Processes as Models for `Self-Similar' Arrival Processes,
and Their Significance for Telecommunications Systems" Department of Computer
Science, University of Nebraska, Lincoln, NE, 8 and 9 April 1997.
``Analytic Modelling of `Self-Similar' Traffic Using Power-Tail
Distributions," Performance Modelling Group, AT\&T Labs, Holmdel, NJ,
22 September,1997.
``Power-Tail Distributions and Their Significance in the Behavior of
Computer and Telecommunications Systems," Performance Modelling Group,
BGS Systems, Waltham, Mass, 14 November 1997.
``Why Standard Models Don't Work For Telecommunications Systems, and an
Analytic Method, The N-Burst Process, That Does," Department of Computer
Science, Regensburg Fachhochschule, Regensburg, Germany, 10 June 1998.
``Why Standard Models Don't Work For Telecommunications Systems, and an
Analytic Method, The N-Burst Process, That Does," Department of Computer
Science, University of Versailles, Versailles, France, 22 September 1998.
``Why Standard Models Don't Work For Telecommunications Systems, and an
Analytic Method, The N-Burst Process, That Does," Department of Computer
Science, University of Bourgoyne, Dijon, France, 25 September 1998.
Hobbies
Listening to jazz and classical music, playing with my grandchildren,
playing bridge and Spider, hiking
Temporary Material
(pdf encoded file)
