Assorted Details II


Screen shot #12 (Merely a picture to illustrate that our GUI is totally self-explanatory)

Click here to go to our overview of Atmospheric Models.

Click here to go to our discussion of Robust Control Topics.

Click here to see a sampling of topics discussed and our style of doing so within our self-contained TK-MIP.

Click here to go to our relevant Anagrams and Palindromes.

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Dr. Paul J. Cefola, the expert referenced above, has a consultancy in Sudbury, Massachusetts: cefola “at”

Update on Dr. Paul J. Cefola:
Paul J. Cefola, "Semianalytical Propagation Of Satellite Orbits About An Arbitrary Central Body," 
Active Member Affiliation(s) within the IAU
Member of Division A Fundamental Astronomy
Member of Division F Planetary Systems and Astrobiology
Member of Commission A2 Rotation of the Earth
Member of Inter-Division A-F Commission Celestial Mechanics and Dynamical Astronomy
Member of Cross-Division A-F Commission Solar System Ephemerides
Past affiliation(s) within the IAU
Past Member of Commission 7 Celestial Mechanics & Dynamical Astronomy (until 2015).
Past Member of Division I Fundamental Astronomy (until 2012).

Click here to get the (draft copy) of AIAA Standards for Atmospheric Modeling, as specified by the various U.S.and other International agencies.

With Prompters_On, we are less diplomatic and say what we really think (and can back-up)! Work on Robust Control over a decade and a half by the mid 1990's could merely handle Linear Time Invariant (LTI) systems with no nonlinearities, no time-varying parameters, and no noise disturbances present. The only disturbance Robust Control could handle successfully was a persistent constant bias offset. The real world is nonlinear and, even when locally linearized, it is usually properly modeled as being time-varying in general. One prominent Laboratory for Information and Decision Systems (LIDS) formulation at MIT for Robust Control (Lopez, J. E., Athans, M, “On Synthesizing Robust Decentralized Control,” American Control Conference, 1994-TK7855.M41.E3845 no. 2197 at Barker Library at MIT) requires that the system state dimension, the number of components of the output measurements, and the number of components of the control all be of the same exact dimension in common as well as the system being just LTI. This formulation is not very realistic (as an understatement since most systems will not exhibit these characteristics). Yet TK-MIP still reports here on the best that TeK Associates has found that: (1) heroically handles one scalar nonlinearity in an otherwise LTI system; (2) heroically handles one scalar time-varying parameter in an otherwise LTI system; and (3) heroically handles one scalar noise component in an otherwise LTI system. 

Apparently, none of these Robust Control formulations can yet handle all three of these situations simultaneously [in the mid-1990's]. Therefore Robust Control is evidently a much less capable methodology than what can be routinely handled in a straightforward manner within existing standard prior state variable formulations. LTI is needed to apply the Robust Control methodology since the new toy for these analysts, consisting of left and right lambda matrix factorizations, are performed in the frequency domain. By being so very conservative (in a minimax sense) by how Robust Control handles system control aspects by single-mindedly focusing on the worse case system characteristics and then by trying to do the best it can with the worse aspects, the subsequent system response is typically very, very sluggish! Few real applications can tolerate such unpleasantly slow response characteristics except, perhaps, in process control. This limited applicability should be emphasized more in the Robust Control literature as a standard disclaimer to the unwary. To date, this has not happened. TeK Associates is aware that, in 2009, there were about 40 books by different authors on how to apply Robust Control to applications. In our opinion, if the only objective is a ticket to a technical conference to present a paper on the subject, then this topic is germane. If the objective is to solve real-world problems in a timely manner with realistic resources (as historically had been the goal), then  perhaps use of Robust Control is not the path to follow. (TeK Associates has even actually overheard [in a public forum prior to the speaker going to participate in a crew event that weekend at “The Head of the Charles Regatta” (at Harvard University but the meeting where this event took place was not at Harvard)] this visiting Robust Control and Intelligent Control researcher’s flim-flam artist-like response to project funders at the end of the rainbow (to allow the researcher to save face): “Oops, the resulting solution is, unfortunately NP-hard, and therefore not tenable. Sorry!”, as he rehearsed and “broadcast as a shout out” for others to use as well in similar situations or circumstances. Talk about “biting the hand that feeds you!” Is this not welfare for Ph.D.’s? In a bygone era, control theorists used their considerable intellect to actually improve the world. Who, with undue or unwarranted influence, lead them so far astray? Fortunately or unfortunately, TeK Associates thinks it knows the answer. What was muttered in antiquity at the walls of Troy, at the sight of the large wooden horse?  

(The above cartoon refers merely to one particular person at MIT and not to a group or class)

He was one of several of my personal idols from 1967 for at least two decades until I could see more... (like seeing behind the wizard's curtain in the Wizard of Oz) and then I became somewhat disappointed and disillusioned.

With the apparent current lack of technical integrity and adequate oversight in a closed club, is it any wonder the U.S. is in its current predicament? [Well that pretty much proves that I have the jaw bone of an ass.... Now all I need to do is to let my hair grow longer and find a Delilah. Finding one shouldn't be too hard since so many of them abound.]

I need to properly acknowledge the research team that was able to accomplish Robust Control solutions via the above cited "heroic" methods: within a 2 year MIT Lincoln Laboratory funded IR&D contract that was performed ~1991 by Dr. Appa Madiwale (MIT Lincoln Labatory) and consultant Prof. Lena Valavani (MIT).

At the 1992 (or was it 1998?) Conference on Decision and Control, a Robust Control Design Challenge was levied, and several investigators rose to the challenge and submitted abstracts promising solutions to be presented at the subsequent year’s Conference on Decision and Control. The authors who planned to participate with their solutions looked like a who’s who in modern control. Despite the simplicity of the low dimensional example comprising the system to be designed for robust control, every anticipated presenter has a void in the proceedings of this subsequent year’s conference where the promised solutions should have appeared. What an embarrassment! This should have been a reality check early on regarding problems with the robust control methodology.

Although the late George Zames is credited in a moving (and extremely informative) tribute by MIT Prof. Sanjoy Mitter on pp. 590-595 in the May 1998 issue of IEEE Trans. on Automatic Control with, essentially, single-handedly bringing mathematical functional analysis to the aid of control and system theory via use of the contraction mapping principle (CMP) in Zames, G., “Feedback and Optimal Sensitivity: model reference transformations, multiplicative semi-norms, and approximate inverses,”  IEEE Trans. on Auto. Contr., Vol. 26, pp. 744-752, Apr. 1981. (see Bensoussan, A., Stochastic Control by Functional Analysis Methods, Vol. II, North-Holland Publishing, NY, 1982 and see Kreyszig, E., Introductory Functional Analysis with Applications, John Wiley & Sons, NY, 1978), please peruse the earlier contribution by Jack M. Holtzman’s (Bell Telephone Lab., Whippany, NJ) Nonlinear System Theory: A Functional Analysis Approach, Prentice-Hall, 1970, which also has the use of CMP as its main theme in such systems. However, Holtzman worked everything out in detail in the above cited book so that his results were on a platter in such a form that they could be easily understood and conveniently applied immediately to practical system design by engineering readers faced with real applications and who may not necessarily be interested in abstract results in a technical paper whose significance is not known until several years later. Charles Desoer’s and M. Vidyasagar’s (U. C., Berkley) textbook came out several years earlier than Zames too and also had a functional analysis bent. A. V. Balakrishnan (UCLA) has also been an avid practitioner of functional analysis in analyzing the behavior of systems and in understanding optimal control (including his contributions to numerical solution algorithms) since the early 1960’s. There is even another precedent for utilizing a contraction mapping to converge to the fixed point solution in: Kerr, T. H., “Real-Time Failure Detection: A Static Nonlinear Optimization Problem that Yields a Two Ellipsoid Overlap Test,” Journal of Optimization Theory and Applications, Vol. 22, No. 4, pp. 509-535, August 1977. Again for MIT, the well-known Not Invented Here ("NIH") syndrome seems to be at play  (i.e., only cite work from people affiliated with MIT in some way and ignore the rest even if they had priority in their results). With this, I keep my personal promise to the late Dr. Harold Chestnut, VP at General Electric in Schenectady, NY in the early 1970’s, to be vigilant on these issues (see Chestnut, H., “Bridging the Gap in Control - Status 1965,” IEEE Trans. on Automatic Control, Vol. 10, pp. 125-126, Apr. 1965 [and evidently still a problem today if not more so]). Also see more about Dr. Harold Chestnut in: , , 

In our opinion, if Control Theorists were actually interested in implementing a Robust Control, they would embrace the work of the IEEE Reliability Society (as it has evolved since the end of WWII) by also viewing the problem at a higher level involving the same constituent components participating within the principal path of implementing the solution and also utilize:

Reliability calculations using Mean-Time-To-Failure (MTTF) associated with each of the main components occurring/participating in postulated alternative control system architectures to achieve the same specified goal that is aspired to;

Availability [i.e., reliability with Mean-Time-To-Repair (MTTR)] for the above including sensors and transducers and actuators;

use of triple hardware redundancy;

use of voting between components (for three or more identical components);

benefits of "warm standby system" versus "cold standby system" components;

"m-out-of-n back-up" with identical components or identical sensors and actuators, where m < n;

"mid-point select strategy" (where warranted for three or more identical components or identical sensors);

algorithms for "real-time detection" of component or sensor failures;

Inclusion and evaluation of the two types of decision errors incurred: "Probability of Miss" and "Probability of False Alarms" associated with the above detection algorithms, where Probability of Miss = 1 - Probability of Correct Detection;

Use of system reconfiguration to meet goals (and [when things go wrong] not merely resort to use of (MIT Aero. & Astro. Prof. John Deyst's) "analytic redundancy" (Deyst, J. J., A Design Approach to Highly Reliable Flight Control Systems, The Charles Stark Draper Laboratory, Inc., Cambridge, MA, 1975; Montgomery, R. C., and Price, D. B., "Management of Analytical Redundancy in Digital Flight Control Systems for Aircraft," AIAA Paper 74-887, Aug. 1974), which should only be a temporary stop-gap measure for failsafe behavior, especially since "analytic redundancy" frequently requires (i.e., resorts to) more processing (and consequential time delay) to obtain the missing sensor information from the equations that model and describe the situation and is therefore more fragile but still desirable to have as a back-up and internal cross-check or as a type of sanity-check on existing unfailed sensors as well). It is an excellent idea to utilize and exploit "analytic redundancy";

Use of more realistic "3-state switches" in such reconfigurations, rather than use "ideal switches" (being idealizations that never miss and never false alarm), as should be considered in whole system or entire system Reliability calculations

Truthful and vigilant robustness needs to consider all the above aspects as well!

 An example on how to handle such considerations is found in: Kerr, T. H., “Failure Detection Aids for Human Operator Decisions in a Precision Inertial Navigation System Complex,” Proceedings of Symposium on Applications of Decision Theory to Problems of Diagnosis and Repair, Keith Womer (editor), Wright-Patterson AFB, OH: AFIT TR 76-15, AFIT/EN, Oct. 1976, sponsored by Dayton Chapter of the American Statistical Association, Fairborn, Ohio, June 1976. 

For failsafe or Fault-Tolerant computer capabilities, look to Stratus Computers (now Stratus Technologies with its [Virtual Operating System-VOS] and EMC
locally in Massachusetts and nationally to Tandem Computers and Sequoia (fault-tolerant Unix systems) in California. They possess hardened operating systems, onboard diagnostic tools, and sophisticated workload-management software that complements the hardware redundancy. Among other things, such fault-tolerant software is designed to prevent the loss of data during failures and to manage tasks such as forced switchovers from a failed system.

See IEE Proceedings A - Physical Science, Measurement and Instrumentation, Management and Education - Reviews ( Volume: 128 , Issue: 4 , pp. 257 - 272, May 1981). Abstract: The paper reviews the methods by which reliable processing and control can be achieved using fault-tolerant digital computers. The motivation for employing such systems is discussed, together with an indication of current and potential areas of application. The features of fault-tolerant computers are described in general terms, together with a system design procedure specific to the development of a reliable computer. The adherence to a well structured design methodology is particularly important in a fault-tolerant computer to ensure an initially fault-free system. In order to follow this design procedure an intimate knowledge of the following subject areas is required: fault classification, redundancy techniques and their relative merits and reliability modeling and analysis. These topics are covered in the paper, with particular emphasis being placed upon the implementation of hardware, software, data and time-redundancy techniques. Examples of fault-tolerant computers proposed and produced in the last decade are described. The availability of Large Scale Integrated circuits (LSI) and, in particular, microprocessors will have a profound effect on the development and application of fault-tolerant computers. The implications of using LSI in this area are therefore discussed including a brief description of two fundamentally different approaches to the realization of a fault tolerant microcomputer.  

Also see: Fault-Tolerant Computing 1 This chapter is based in part on portions of Chapter 8 of “Computer Hardware/Software Architecture,” by Wing N. Toy and Benjamin Zee (Prentice-Hall, 1986), and “Microprogrammed Control and Reliable Design of Small Computers,” by George D. Kraft and Wing N. Toy (Prentice-Hall, 1981) in Advances in Computers, Elsevier, 1987.

Robust Control methodology (apparently a "new toy" of control theorists in the last 30 years is evidently of limited applicability in practice since Robust Control implementations have a sluggish response that few applications can tolerate other than those in the process control industry and even then this theory is stymied by presence of nonlinearities, time-varying parameters, or noises).

This new (frequency-domain only) predominately linear Robust Control approach provides NO new solutions NOR additional applications that it can solve beyond what previous theory already adequately handled (& handled exceptionally better for nonlinear, time-varying, noisy systems, and real systems of higher dimensional state sizes). We acknowledge that there are indeed a few examples where Robust Control does, in fact, handle a "non-linearity" present in only one loop, "time-varying" present in only one loop, and "noisy systems" present in only one loop; but, apparently, can only handle one-situation at a time but only by "heroic" efforts to date! 

While I am not intimidated by measure theory, nor by Lebesgue integrals in rigorous probability theoretic considerations, nor by other stochastic integrals such as that of Ito or Stratonovich or MacShane, nor by exotic norms in a Banach Space nor exotic inner products in a Hilbert Space, I fail to see any enticing overriding lure of Hardy spaces, and especially H for control and/or estimation. I am satisfied and happy with L1 or L2 convergence or other Lp spaces, and conjugate exponents: 1/p + 1/q = 1 for related pairs of Lebesgue integrals, L, and Essential Supremum. I am definitely not impressed by "Robust Control" and all its apparent pretensions. However, some useful motivation for its use is provided here:  and, subsequently or consequentially, here: Notice that the language is indeed that of "process control": slow and steady wins the race as in the story of the "Tortoise and the Hare" (so I did not exaggerate in my earlier criticism of Robust Control or H estimation as having an inherently sluggish response similar to the characteristic response of an "over damped" system rather than to the preferred  "critically damped" 2nd order LTI system that does not exhibit ringing oscillations nor overshoot but quickly and smoothly goes to the final target state in response to the most recent set-point value submitted). While we understand that Lp spaces have pathologies when p < 1, that Hp spaces don't exhibit when p < 1 (useful for further mathematical analysis but not related to Control Theory applications [even for process control], we are less enthusiastic concerning use of Hp spaces for practical engineering applications).

For the inner and outer loops of Fighter Aircraft guidance and control, several generations of linkages have evolved since Generation 1: pneumatic linkages and mechanical levers to exercise control actuators; through Generation 2: fly-by-wire (electrical cables) to exercise control actuators; to Generation 3: fly-by-light (i.e., fiber optic links) to exercise control actuators. Fiber optic cables would previously be bleached and turn cloudy (interfering with successful communications transmission) upon exposure to a nuclear environment unless they were doped with a "Halide" such as fluorine. There are now more modern solutions to that historical problem.  

M. G. Safonov and M. K. H. Fan, eds., Special Issue on Multivariable Stability Margin. International Journal of Robust and Nonlinear Control, Vol. 7, pp. 97–103 (1997). 

Kevin A. Wise, "Bank-to-turn missile autopilot design using loop transfer recovery," AIAA Journal of Guidance, Control, and Dynamics, Vol. 13, No. 1, pp. 145-152, Jan-Feb. 1990. 
Published Online:23 May 2012  
As TeK Associates has observed or warned earlier here and elsewhere, that Loop Transfer Recovery (LTR) for LQG can only be invoked or implemented for LTI (Linear Time Invariant) systems. This is not likely the case for Bank-to-Turn missiles (except, maybe, only for one mode as a less realistic case).

Christopher I. Marrison and Robert F. Stengel, "Design of Robust Control Systems for a Hypersonic Aircraft," AIAA Journal of Guidance, Control, and Dynamics, Vol. 21, No. 1, pp. 58-63, Jan-Feb 1998. 
Published Online:23 May 2012  

Perhaps use of "Gain Scheduling" of various PID controllers (optimized for useful control of specific regions of the linearized nonlinear system) will 
suffice for many useful practical applications. Smooth transitions in switching between different design "set points" will also need to be included in the 
implementation. Finally, the utility of the particular "Gain Scheduled" PID implementations should be demonstrated by copious simulations of the exact  
nonlinear system
, as controlled by the PID Gain schedule, to verify that the resulting design is adequate for the intended nonlinear application.

For more insight into "Gain Scheduling", please click on: 

Gain Scheduling Basics: Gain scheduling is an approach to control of nonlinear systems using a family of linear controllers, each providing satisfactory 
control for a different operating point of the system. Gain-scheduled control is typically implemented using a controller whose gains are automatically 
adjusted as a function of scheduling variables that describe the current operating point.

We at TeK Associates are optimistic about the status of control theory in general and we are enthusiastic about:

Bossert, D. E., Lamont, G. B., Horowitz, I., “Design of Discrete Robust Controllers using Quantitative Feedback Theory and a Pseudo-Continuous-Time Approach,” on pp. 25-31 in Osita D. T. NWOKAH (Ed.), Recent Developments in Quantitative Feedback Theory: Work by Prof. Issac Horowitz (predating research in Robust Control by two decades), presented at the winter annual meeting of the American Society of Mechanical Engineers,  Dallas, TX, 25-30 Nov. 1990;

Barnard, R., “A Quantitative Feedback Theory Based on Time Domain and Fixed Point Notions (as a consequence of contraction mappings encountered),” on 45ff. in Osita D. T. NWOKAH (Ed.), Recent Developments in Quantitative Feedback Theory: Work by Prof. Issac Horowitz, presented at the winter annual meeting of the American Society of Mechanical Engineers,  Dallas, TX, 25-30 Nov. 1990;

Intelligent Control and Adaptive Systems, Ed./Chair Guillermo Rodriguez, Proceedings of SPIE-The International Society for Optical Engineering, Vol. 1196, Bellingham, WA, 7-8 Nov. 1989;

Butkovskiy, A. G., Pustyl'nikov, A. M., Mobile Control of Distributed Parameter Systems, Ellis Horwood Ltd., Chichester, Halstead Press, division of John Wiley, NY, 1997 (especially see Appendix 6 for 23 varieties of Integral Transforms on pp. 249-267; Appendix 7: Sobolev Transform; Appendix 12: On an Approximation Investigation of Mobile Control Problems for Distributed Control);

Becedas, J., Mamani, G., Feliu, V., Siva-Ramirez, H., “Estimation of Mass-Spring-Damper System,” in Advances in Computational Algorithms and Data Analysis, S.-I. Ao, B. Kieger, S.-S. Chen (Eds.), Springer Science & Business Media, 2009;

Schlacher, K., Irschik, H., Kugi, A., “Control of Nonlinear Beam Vibrations by Multiple Piezoelectric Layers,” pp. 355-362 in IUTAM Symposium on Interaction between Dynamics and Control in Advanced Mechanical Systems, D. H. VanCampen (Ed.), Kluwer Academic Publishers, Netherlands, 1997;

Hajek, O., Control Theory in the Plane, 2nd Edition, Lecture Notes in Control and Information Sciences, Springer-Verlag, NY, 2009;

Ching, S.-N., Eun, Y., Gokcek, C., Kabamba, P. T., Meerkov, S. M., Quasilinear Control: Performance analysis and design of feedback systems with nonlinear sensors and actuators, Cambridge University Press, Cambridge, UK, 2011.

To complete the expose started above, recall the creatively designed endeavor below which featured a multiple model bank of N Kalman filters in parallel with an LQ feedback regulator control law for each Kalman filter equipped feedback branch after which the aggregated net result of the particular scalar weightings consisting of the individual probabilities, as calculated on-line in real-time, and corresponding to any particular branch of the LQG being correctly associated with the present mode (of only N different possible modes being modeled) for the actual multi-mode system under consideration:

Athans, M., Castanon, D., Dunn, K.-P., Lee, W. H., Sandell, N. R., Willsky, A. S., “The Stochastic Control of the F-8C Aircraft using a Multiple Model Adaptive Control (MMAC) method - I: Equilibrium Flight,” IEEE Trans. on Automatic Control, Vol. 22, No. 5, pp. 768-780, Oct. 1977. Was non-equilibrum flight ever considered or handled (where non-equilibrium flight is take-offs and landings and dog fight maneuvers or even maneuvers as benign as just coordinated turns)? Did this approach actually work? Was there ever a Phase II follow-on thus indicating success of the particular approach? The answer appears to be “no” on all three counts. This constitutes a high profile publicity stunt or charade without any useful payoff to the NASA customer. This was business as usual in some circles! I definitely would like to chase the money changers from the temple (of learning and useful knowledge). If they had not been pretending so hard that LQG theory was not fatally flawed, they could have equipped each LQG leg with a stable replacement LQG/Loop Transfer Recovery, as its correction. The resulting redesign may now actually work as they had hoped the initial version would.

Perhaps the funniest situation was when several people complained that the IEEE TAC paper review system was, perhaps, apparently being abused by reviewers or assistant editors being the first to see and then recognize a significant new result and then dispatch a graduate student (among an ample pool of available talent) to either use the topic of the paper under review as their thesis or write a paper on the topic themselves and then submit it for publication even before the original paper had appeared in print for the first time (a process that took about two years in those days). Afterwards, people at a particular institution would just reference the work of the authors affiliated with the same institution and ignore the true originator (who should have been acknowledged as having had the precedent) as yet another example of the "NIH" syndrome. What was funny was who was on the two man committee: Prof. Michael Athans and Prof. Y.-C. "Larry" Ho [one who almost always indulged in "NIH" behavior and the other who didn't and was known for his steadfast integrity, respectively] to look into the possible problem and who jointly reported their conclusions that everything regarding the current IEEE TAC review process was just fine! Isn't that particular situation like “having the fox guard the chicken coop?”

In the old days (1970's and, perhaps, before), in order for a Navy Sea Hawk SH-60 helicopter to land on a ship's deck during high winds and a corresponding "high sea state", it would drop a strong steel cable that would be attached to a winch aboard ship. Then the helicopter would pull up against the cable to make the cable taught as the winch reeled it in. In that way, the helicopter would perfectly match the ship's motion on roughest of seas as it landed. RAN MH-60 Helicopter RAST Recovery Assist Explained: 

Years later (~1990's), I heard a presentation by (the late) Prof. Mike Athans at MIT (& Alphatech), where there was an attempt to do everything without the cable and, instead, rely only on a laser radar down and retroreflector-based back bounce control law for the landing. Even though I did not observe a cable in the above video, I still suspect that the complicated approach just described was not used here. The cable approach is robust and straight-forward. Judging by the way the helicopter moves perfectly to match the heaving of the ship's deck without any apparent computational delay (that would be incurred if a laser radar and a control law implementation were jointly used to control the helicopter's landing), I strongly suspect that there is a cable present. Modern cables can be made of carbon "Buckyballs" now for sufficient tensile strength without being easily visible to the naked eye. (At least it is something useful and a practical application for Buckyballs instead of a somewhat controversial (understatement) hypothesized "Space Elevator".
Click to view Japan's solution:

One further example: I am not accusing all of MIT of practicing "NIH" but am only complaining about the inner workings of one particular department that I am very familiar with: Electronic Systems Laboratory (ESL), which changed its name to Laboratory for Information and Decision Systems (LIDS). My complaint is only for a particular time epoch from the late 1960's until some aspects of the present and does not include or apply to everybody working in this department, nor to the students who graduated from this department; but merely to the "trickster" at the top for many of those years [who was also a brilliant teacher and insightful researcher with extensive breath and depth and an ability to communicate ideas simply and clearly so that ALL could understand]. (My own [115] was based on some of his earlier work.) However, in the 1990's, he even told his graduate students in class (which I overheard, as an outside member of the audience) how he handled the following situation: "One of my prior students, who had already graduated and was now working in industry, in seeking to apply some aspect of my prior published technique to a particular application in seeking to apply my earlier results to but then, unfortunately, encountered a problem in taking it to fruition in the manner expected. This graduate, now in industry, successfully persuaded his supervisor to finance a consulting visit for me to help resolve the problem and help them get over the perceived temporary hurdle. While there on location, I sought a private audience with my prior student's supervisor from whom this employee, got that consulting assignment for me; I told his supervisor that he "was not the sharpest knife in the drawer"!" Again, “biting the hand that feeds him!” Paying back an act of kindness by throwing his former student "under the bus". Prof. Michael Athans' meaning was clear: "If you bother me with some theoretical aspect or "wrinkle" associated with the material of this course after you leave here, I will do the same thing to you!" Usually, subsequent consulting work on the same topics and material already known and conveyed in prior classes on the subject is viewed as an opportunity to be a hero and "save the day" for its industrial application! It's a pity that Prof. Athans, apparently, did not view it that way. Perhaps later in life, he was merely too busy and did not want to interrupt what he was working on at the time. I will remember the fun times (e.g., at several meetings of the CDC in New Orleans, as he crossed Canal Street, with an impish grin on his face, and as he proceeded down Bourbon Street with Sol Gully [] to take in some of the many performances there). Prof. Athans had a very colorful personality. He will indeed be missed!

We at TeK Associates consider ourselves to have been extremely lucky for over more than forty years by our employers being in convenient proximity of two major educational institutions of higher learning where outstanding leaders in control theory taught; and who allowed us to attend important outside lecturers and presentations for free at both Harvard University (where Y. C. "Larry" Ho allowed us to hear but not ask questions nor make comments) and MIT (where we were allowed to ask probing questions). We also had library cards at both institutions, which greatly aided our research into these subjects. Weekly attendance at TASC "White Noise Hours" also provided us with experience more encompassing than our own mere first-person experience because we benefited from direct cross-corroboration with others who had different challenges. I also frequently used the Engineering and Science Library at Boston University, the Snell Library at Northeastern University, the Air Force Geophysical Library at Hanscom Field AFB (which became the Phillips Library) before it all moved to Albuquerque, New Mexico, the Lincoln Laboratory Library while I was working there, and the MITRE library in Bedford, MA (while I was consulting there) before it was dismantled in the early 2000's to be merely a "shadow of its former self".

Another variation of sorts of the dreaded NIH syndrome, discussed above, occurs in the following:

Smith, S. T., “Statistical Resolution Limits and the Complexified Cramer-Rao Bound,” IEEE Trans. on Signal Processing, Vol. 53, No. 5, pp. 1597-1609, May 2005.

Smith, S. T., “Covariance, Subspace, and Intrinsic Cramer-Rao Bounds,” IEEE Trans. on Signal Processing, Vol. 53, No. 5, pp. 1610-1630, May 2005.

where no reference is made to the following prior publication on this Cramer-Rao Lower Bound topic:

Kerr, T. H., “Status of CR-Like Lower bounds for Nonlinear Filtering,” IEEE Transactions on Aerospace and Electronic Systems, Vol. AES-25, No. 5, pp. 590-601, September 1989 (Author’s reply in Vol. AES-26, No. 5, pp. 896-898, September 1990).

yet several of the references cited in the above papers by Stephen Smith (of the Lincoln Laboratory of MIT) do, in fact, reference the above Kerr article as a significant historical precedent in the Cramer-Rao Lower Bound topic area that was published in a different IEEE Journal even though Kerr was in fact an employee of Lincoln Laboratory when his paper was published but is no longer (for good reasons such as this).  Substantiation of its significance may be found on page 9 in: Branko Ristic, “Cramer Rao Bounds for Target Tracking,” International Conference on Sensor Networks and Information Processing, 6 Dec. 2005.

No there is not “a new sheriff in town” since THK III has pretty much been here and on station all along with eternal vigilance since 1971: “Making a list and checking it twice---trying to find out who’s naughty or nice...(You can run but you can't hide!)”
Click here to view our recent short comment submitted to the Institute of Navigation for publication in their Journal. Kerr, T. H., “Comment on 'Low-Noise Linear Combination of Triple-Frequency Carrier Phase Measurements',” Navigation: Journal of the Institute of Navigation, Vol.57, No. 2, pp. 161,162, Summer 2010.
Kerr, T. H., “Comment on ‘Precision Free-Inertial Navigation with Gravity Compensation by an Onboard Gradiometer’,”  AIAA Journal of Guidance, Control, and Dynamics, July-Aug. 2007.
Kerr, T. H., “Comments on ‘Determining if Two Solid Ellipsoids Intersect’,” AIAA Journal of Guidance, Control, and Dynamics, January-February 2005.
Kerr, T. H., “Further Critical Perspectives on Certain Aspects of GPS Development and Use,” Proceedings of 57th Annual Meeting of the Institute of Navigation, 9-13 June 2001.
Kerr, T. H., “Sensor Scheduling in Kalman Filters: Evaluating a Procedure for Varying Submarine Navaids,” Proceedings of 57th Annual Meeting of the Institute of Navigation, 9-13 June 2001.
Kerr, T. H., “Vulnerability of Recent GPS Adaptive Antenna Processing (and all STAP\SLC) to Statistically Non-Stationary Jammer Threats,” Proceedings of SPIE, Session 4473: Tracking Small Targets, 29 July-3 August 2001.
Kerr, T. H., “Exact Methodology for Testing Linear System Software Using Idempotent Matrices and Other Closed-Form Analytic Results,” Proceedings of SPIE, Session 4473: Tracking Small Targets, 29 July-3 August 2001. (closed-form analytic solutions and IMM critique near the end)
Kerr, T. H., “New Lamps for Old: a shell game for generalized likelihood ratio use in radar? Or this isn’t your father’s GLR!,” Proceedings of SPIE, Session 4473: Tracking Small Targets, 29 July-3 August 2001.
Kerr, T. H., “TeK Associates’ view in comparing use of a recursive Extended Kalman Filter (EKF) versus use of Batch Least Squares (BLS) algorithm for UEWR,” TeK Associates, Lexington, MA, (for Raytheon, Sudbury, MA), 12 Sep. 2000.
Kerr, T. H., “Considerations in whether to use Marquardt Nonlinear Least Squares vs. Lambert Algorithm for NMD Cue Track Initiation (TI) Calculations,” TeK Associates Technical Report No. 2000-101, Lexington, MA, (for Raytheon, Sudbury, MA), 27 Sep. 2000.
Kerr, T. H., “Critique of Some Neural Network Architectures and Claims for Control and Estimation,” IEEE Transactions on Aerospace and Electronic Systems, April 1998.
Kerr, T. H., “Comments on ‘An Algorithm for Real-Time Failure Detection in Kalman Filters’,” IEEE Trans. on Automatic Control, May 1998.
Kerr, T. H., “A Critical Perspective on Some Aspects of GPS Development and Use,” Proceedings of 16th Digital Avionics System Conference, Vol. II, pp. 9.4-9 to 9.4-20, Irvine, CA, 26-30 Oct. 1997.  [all worries expressed here by the author regarding GPS vulnerabilities were confirmed in experience in Three W. Mark Barnes, "Artillery Surveyors: Nomads of the Battlefield," Field Artillery, A Professional Bulletin for Redlegs, HQDA P B6-01-1, pp.43-47, Jan.-Feb. 2001]
Kerr, T. H., “Extending Decentralized Kalman Filtering (KF) to 2D for Real-Time Multisensor Image Fusion and\or Restoration: Optimality of Some Decentralized KF Architectures,” Proceedings of the International Conference on Signal Processing Applications & Technology (ICSPAT96), 7-10 October 1996.
Kerr, T. H., “Assessing and Improving the Status of Existing Angle-Only Tracking (AOT) Results,” Proceedings of the International Conference on Signal Processing Applications & Technology (ICSPAT), 24-26 October 1995.
Kerr, T. H., “Use of GPS\INS in the Design of Airborne Multisensor Data Collection Missions (for Tuning NN-based ATR algorithms),” Institute of Navigation Proceedings of GPS-94, 20-23 Sept. 1994.
Kerr, T. H., “Emulating Random Process Target Statistics (using MSF),” IEEE Transactions on Aerospace and Electronic Systems, Vol. 30, No. 2, pp. 556-577, April 1994. (closed-form analytic solutions and critique in Appendix)
Kerr, T. H., “Streamlining Measurement Iteration for EKF Target Tracking,” IEEE Transactions on Aerospace and Electronic Systems, March 1991.
Kerr, T. H., “An Invalid Norm Appearing in Control and Estimation,” IEEE Transactions on Automatic Control, Vol. 23, No. 1, Feb. 1978.  (counterexamples and a correction)
Kerr, T. H., “Testing Matrices for Definiteness and Application Examples that Spawn the Need,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 10, No. 5, pp. 503-506, Sept.-Oct., 1987. 
Kerr, T. H., “Rationale for Monte-Carlo Simulator Design to Support Multichannel Spectral Estimation and/or Kalman Filter Performance Testing and Software Validation/Verification Using Closed-Form Test Cases,” MIT Lincoln Laboratory Report No. PA-512, Lexington, MA, 22 December 1989 (BSD). 
Kerr, T. H., “Status of CR-Like Lower bounds for Nonlinear Filtering,” IEEE Transactions on Aerospace and Electronic Systems, Vol. 25, No. 5, pp. 590-601, Sep. 1989. (an expose) 
Kerr, T. H., “On Misstatements of the Test for Positive Semidefinite Matrices,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 13, No. 3, pp. 571-572, May-Jun. 1990. (occurring in Nav & Target Tracking s/w in ‘70’s/’80's)
Kerr, T. H., “Fallacies in Computational Testing of Matrix Positive Definiteness/Semidefiniteness,” IEEE Transactions on Aerospace and Electronic Systems, Vol. 26, No. 2, pp. 415-421, Mar. 1990. [Using counterexamples, he identifies fallacious algorithms that he found to exist in U.S. Navy submarine navigation and sonobuoy operational software that he reviewed in the late 1970's and early 1980's.]
 Kerr, T. H., “Computational Techniques for the Matrix Pseudoinverse in Minimum Variance Reduced-Order Filtering and Control,” in Control and Dynamic Systems-Advances in Theory and Applications, Vol. XXVIII: Advances in Algorithms and computational Techniques for Dynamic Control Systems, Part 1 of 3, C. T. Leondes (Ed.), Academic Press, NY, 1988.
Kerr, T. H., “Decentralized Filtering and Redundancy Management Failure Detection for Multi-Sensor Integrated Navigation Systems,” Proceedings of the National Technical Meeting of the Institute of Navigation (ION), San Diego, CA, 15-17 January 1985. (an expose)
Kerr, T. H., “Decentralized Filtering and Redundancy Management for Multisensor Navigation,” IEEE Trans. on AES, Vol.23, No. 1, pp. 83-119, Jan. 1987. (an expose)
Kerr, T. H., “Examining the Controversy Over the Acceptability of SPRT and GLR Techniques and Other Loose Ends in Failure Detection,” Proceedings of the American Control Conference, San Francisco, CA, 22-24 June 1983.  (an expose)
Kerr, T. H., “Comments on ‘A Chi-Square Test for Fault Detection in Kalman Filters’,” IEEE Transactions on AC, Vol. 35, No. 11, pp. 1277-1278, November 1990.
Kerr, T. H., “A Critique of Several Failure Detection Approaches for Navigation Systems,” IEEE Transactions on AC, Vol. 34, No. 7, pp. 791-792, July 1989.
Kerr, T.H., and Chin, L., “The Theory and Techniques of Discrete-Time Decentralized Filters,” in Advances in the Techniques and Technology in the Application of Nonlinear Filters and Kalman Filters, edited by C.T. Leondes, AGARDograph No. 256, Noordhoff International Publishing, Lieden, 1981.
Kerr, T. H., “The Proper Computation of the Matrix Pseudo-Inverse and its Impact in MVRO Filtering,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 21, No. 5, Sep. 1985.
Kerr, T. H., “The Principal Minor Test for Semidefinite Matrices-Author’s Reply,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 13, No. 3, p. 767, Sep.-Oct. 1989.
Kerr, T. H., “Three Important Matrix Inequalities Currently Impacting Control and Estimation Applications,” IEEE Transactions on Automatic Control, Vol. AC-23, No. 6, December 1978.
Kerr, T. H., “Functional and Mathematical Structural Analysis of the Passive Tracking Algorithm (PTA),” Intermetrics Report No. IR-MA-208, Cambridge, MA, 25 May 1983, for NADC.
Kerr, T. H., “Comments on ‘Estimation Using a Multirate Filter’,” IEEE Transactions on Automatic Control, Vol. AC-34, No. 3, p. 384, March 1989.
Kerr, T. H., “Comments on ‘Federated Square Root Filter for Decentralized Parallel Processes’,” IEEE Transactions on Aerospace and Electronic Systems, Vol. AES-27, No. 6, November 1991.   Go to Top

Explanations pop-up instantaneously where you need them but only when requested, as seen below for the single button appearing on the screen above. An exception is if the USER sets Prompters_On as an option that can be activated from the Menu Bar appearing on most of the primary Screens. When Prompters_On is set, many of the informational screens open automatically when that screen is visited as a helpful mnemonic device. This feature is especially useful when a substantial period of time elapses between TK-MIP activation as other tasks are being pursued. No user manual is ever necessary to feel comfortable and confident in running TK-MIP. This prompting does not make use of the Internet. Otherwise TK-MIP could not be run in a secure stand-alone CLASSIFIED mode.

The close (equivalent) model relationship between a Box-Jenkins time-series representation and a state variable representation has been known for a least  4 or 5 decades, as spelled out in:  A. Gelb (Ed.), “Applied Optimal Estimation,” MIT Press, Cambridge, MA, 1974.
Kerr, T. H., “Applying Stochastic Integral Equations to Solve a Particular Stochastic Modeling Problem,” Ph.D. Thesis in the Department of Electrical Engineering, University of Iowa, Iowa City, Iowa, January 1971. (This offers a simple algorithm for easily converting an ARMA time-series into a more tractable AR one of higher dimension.)
Kerr, T. H., Multichannel Shaping Filter Formulations for Vector Random Process Modeling Using Matrix Spectral Factorization, MIT Lincoln Laboratory Report No. PA-500, Lexington, MA, 27 March 1989. (This offers a simple algorithm for easily converting an ARMA time-series into a more tractable AR one of higher dimension.)
Kerr, T. H., “Emulating Random Process Target Statistics (Using MSF),” IEEE Trans. on Aerospace and Electronic Systems, Vol. 30, No. 2, pp. 556-577, Apr. 1994. (This offers a simple algorithm for easily converting an ARMA time-series into a more tractable AR one of higher dimension.)

Please click this for a simple overview perspective. 

Update: Now 50 years of experience with Kalman Filter applications and he is an IEEE Life Senior Member and an Associate Fellow of the AIAA in GNC and a Member of SPIE. 

The buttons depicted in the screen immediately above represent a dynamic application overview available to the seated
operator (in blue silhouette) at a console who is keeping abreast of the situation. When our TK-MIP USER clicks these particular buttons,
a short unclassified video segment is played depicting the dynamics of the indicated application performing properly, as designed.

Please click on for free ways to check your Window's registry for compatibility with TK-MIP and its ability to automatically access the various file extensions that it needs to access (as representatively sampled in the file view above) in order that TK-MIP work properly without conflict after it is installed.

Please click on for free ways to check your Window's registry for compatibility with TK-MIP and its ability to automatically access the various file extensions that it needs to access (as representatively sampled in the file view above) in order that TK-MIP work properly without conflict after it is installed.

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Sh, Tom sees moths. 

Are we not drawn onward to new era?

To Idi Amin. I'm a idiot.

Splat! I hit Alps.

Norma is as selfless as I am, Ron.




Hardware Options for sequential real-data inputs to TeK Associates' TK-MIPTM Software

Other NI conventions using various USB types now exist:  

Others offer Data Acqusition solutions too:  
DMC leverages a variety of programming platforms for success in Test & Measurement solutions. These include LabVIEW and text-based languages (Python
LabWindows/CVI, Measurement Studio, .NET, ASP.NET, C#, C++, C, Java, and more). 

Identifying other DAC approaches that are compatible with Visual Basic:
Marvin Test Solutions's ATEasy: 
NI's TestStand:  

Including additional lesser-known sensor data acquisition options: 
Further considerations and rankings:  (please see ActiveX tools here)
More considerations:  
Get Guide:  
Data Acquisition Methods:  
Data Management Index: 

"Yes, we CAN":

The SUNIX UTS series ComHub transform your USB port into asynchronous RS-422/485 serial ports for communication with serial devices.   
Compatible with both USB 2.0 and 1.1 specifications, SUNIX provides serial ports with transfer speed up to 921.6Kbps. A quick, simple and cost-effective way to bring the advantages of data accessibility and mobile 

solution for kinds of commercial and industrial automation applications. 
Versatile Applications  
RS-422/485 signal is ideal for long-distance communication. For example, our customer, an system integrator of building automation, chose to deploy SUNIX UTS4009PN to smart building projects 

due to the lack of Serial ports on their PC system, which needs to connect many IoT devices.


For completeness and for nostalgia purposes (since we are familiar with standard DoD applications too) 
even though TK-MIP is definitely NOT for use with 1553 buses, click here to see
update in this area too.

Rather than TeK Associates personalizing TK-MIP software to a wide variety of different USER options beforehand, it would be easier (for us) to let the USER perform personalization themselves for the I/O hardware compatibility that they really want!

IMPORTANT: There exists an input signal simulator which can be used to realistically emulate a sequential vector input stream for purposes of initially verifying the computational behavior of TK-MIP before a USER adapts TK-MIP to their preferred data acquisition I/O hardware, as recommended.

Click here to view more of the beauty of Arithmetic rather than of Mathematics, as claimed.

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