Never Trust a Simulation
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Date
Wednesday, December 3, 2003
Time
6:00PM
Subject
Never Trust a Simulation without a Back-of-the-Envelope calculation to Explain it
Description
Simulations are a crucial tool for systems engineers, and I have coded, developed, analyzed, debugged and debunked many such simulations in my 34 years of system engineering. However, they cannot be trusted. All too often system engineers come a cropper due to believing the results of simulations without making sure that the results are correct and relevant. Significant errors can occur for many reasons: bugs, bugs, bugs, incorrect parameters, incorrect physical models, incorrect application of perfectly fine code, incorrect interpretation of accurate results, etc.
As a young system engineer, I was deeply shaped by a system engineering culture that valued simple back-of-the-envelope calculations to provide insight into what was going on. I still remember Bill Shrader's eloquent advice from three decades ago: "never trust a simulation without a back-of-the-envelope calculation to explain it." I have lived by this good advice for my whole career in system engineering, and I find simple back-of-the-envelope calculations to be both useful and esthetically pleasing. Moreover, I am appalled when I see system engineers blindly believe the results of simulations.
This talk will give five or ten examples of system engineering blunders caused by faulty simulations or erroneous physical experiments. This is analogous to the situation in experimental physics, in which many theoretical physicists have learned to distrust experiments that lack sufficient theoretical explanation. For example, Shelley Glashow knew that cold fusion was impossible based on theory alone.
Speaker Bio
Fred Daum is a senior principal fellow, which is the highest technical level at Raytheon. Fred was awarded the Tom Phillips prize for technical excellence, in recognition of his ability to make complex radar systems work in the real world. He developed, analyzed
and tested the real time algorithms for essentially all the large phased array radars built by the USA in the last three decades, including Cobra Dane, PAVE PAWS, Cobra Judy and BMEWS. Fred has also worked on THAAD, UEWR and ROTHR, as well as several air traffic control systems and ship board fire control systems. These real time algorithms include: Kalman filters, radar waveform scheduling, Bayesian discrimination, data association, track initiation, discrimination of satellites from missiles, calibration
of tropospheric and ionospheric refraction, and target object mapping, for which he was recently given the "Radar Scottie Award" for his work on THAAD. Moreover, Fred single-handedly developed, analyzed and tested the real time Bayesian discrimination algorithms for Cobra Dane, Cobra Judy, PAVE PAWS and BMEWS. He is a graduate of Harvard University. Fred's nonlinear filter theory has been applied by engineers at Boeing for the boost phase intercept problem, with results that are vastly superior to the extended Kalman filter. Fred's nonlinear filter theory generalizes the Kalman and Benes filters. He has published nearly one hundred technical papers, and he has given invited lectures at MIT, Harvard, Yale, Brown, Georgia Tech., University of Connecticut (many times), Univ. Minnesota, Univ. of Illinois at Chicago and Northeastern University.
Location
Best Western Tlc Hotel
477 Totten Pond Road, Waltham, MA 02451
781-890-7800
Cost
INCOSE Members $10
Non members: $20
Student members: $5
Payable at the door.
Reservations
Please RSVP to info@incose-ne.org