Robert Shuler - Research Interests, Publications, Papers
Physics & Math - Economics - Investing
Radiation Tolerant CMOS
Patents - Software - Reviews
Current Affiliation: NASA / Johnson Space Center - NASA profile
ORCID: orcid.org/0000-0002-6129-6867
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PHYSICS, INERTIA, GRAVITY & MATH
- Entropy-Like State Counting Leads to Human Readable Four Color Map Theorem Proof (Pure and Applied Mathematics Journal. Vol. 7, No. 3, 2018, pp. 37-44. doi: 10.11648/j.pamj.20180703.12) The problem of how many colors are required for a planar map has been used as a focal point for discussions of the limits of human direct understanding vs. automated methods. It is important to continue to investigate until it is convincingly proved map coloration is an exemplary irreducible problem or until it is reduced. Meanwhile a new way of thinking about surfaces which hide N-dimensional volumes has arisen in physics employing entropy and the holographic principle. In this paper we define coloration entropy or flexibility as a count of the possible distinct colorations of a map (planar graph), and show how a guaranteed minimum coloration flexibility changes based on additions at a boundary of the map. The map is 4-colorable as long as the flexibility is positive, even though the proof method does not construct a coloration. This demonstration is successful, resulting in a compact and easily comprehended proof of the four color theorem. The use of an entropy-like method suggests comparisons and applications to issues in physics such as black holes. Therefore in conclusion some comments are offered on the relation to physics and the relation of plane-section color-ability to higher dimensional spaces. Future directions of research are suggested which may connect the concepts to not only time and distance and thus entropic gravity but also momentum.
- A family of metric gravities With a new exact Schwarzschild method, a local space-time relation, strong-field verification targets, and the ability to promote field gravities to full metricity (The European Physical Journal Plus, 133: 158, April 2018) The goal of this paper is to take a completely fresh approach to metric gravity, in which the metric principle is strictly adhered to but its properties in local space-time are derived from conservation principles, not inferred from a global field equation. The global field strength variation then gains some flexibility, but only in the regime of very strong fields (2nd-order terms) whose measurement is now being contemplated. So doing provides a family of similar gravities, differing only in strong fields, which could be developed into meaningful verification targets for strong fields after the manner in which far-field variations were used in the 20th century. General Relativity (GR) is shown to be a member of the family and this is demonstrated by deriving the Schwarzschild metric exactly from a suitable field strength assumption. The method of doing so is interesting in itself because it involves only one differential equation rather than the usual four. Exact static symmetric field solutions are also given for one pedagogical alternative based on potential, and one theoretical alternative based on inertia, and the prospects of experimentally differentiating these are analyzed. Whether the method overturns the conventional wisdom that GR is the only metric theory of gravity and that alternatives must introduce additional interactions and fields is somewhat semantical, depending on whether one views the field strength assumption as a field and whether the assumption that produces GR is considered unique in some way. It is of course possible to have other fields, and the local space-time principle can be applied to field gravities which usually are weak-field approximations having only time dilation, giving them the spatial factor and promoting them to full metric theories. Though usually pedagogical, some of them are interesting from a quantum gravity perspective. Cases are noted where mass measurement errors, or distributions of dark matter, can cause one theory to mimic another implying that such estimates or distributions should be first obtained from weak-field measurements before being used to discriminate verification candidates. By this method theorists gain insight into the local constraints on space-time, and GR verification gains strong-field comparative objectives.
- Gravity-Independent and Gravity-Related Inertia Fields (Theoretical Physics, vol 2, no 2, pp 51-62, June 2017) This paper first assesses under what conditions the Higgs field has “no deep connection” to gravity, i.e. it is gravity-independent, and also whether it has a connection with or conflicts with other proposed inertia-causing fields such as the vacuum-reaction force. Then it develops a classical consistent field strength (CFS) framework to support analysis of inertia fields that are gravity-related, which seems likely in the case of vacuum-reaction inertia. The framework can produce important exact solutions to Einstein’s field equation. When used with alternative formulations it guarantees equivalence and conservative fields over a wide range of field choices from traditional metric space-time to background-embedded to emergent space-time. A short worked-out gravity-related inertia field example is given. New perspectives on spin and self-gravitation issues are discussed.
- Numerical Geodesic Approximation for Theoretical and Experimental Light Bending Analysis (Advances in Astrophysics, vol 2, no 1, pp 76-85, August 2016) This paper investigates a least-time (or fastest-path) two-point algorithm for numerically propagating a light ray in a gravitational field using anisotropic coordinate velocity and distantobserver coordinates. Rather than imaging or ray tracing, the objective is to support analysis of fundamentals and to be able to find null geodesics in arbitrary metrics. First we establish that results agree with geodesic paths in regard to bending angles to very high accuracy. Then we investigate the bending rate of two coordinate bending angles, wave and displacement, and find that wave angle illustrates well-known points about spatial and time components of light bending, while the displacement angle leads to simple analytic description of Einstein’s comment about the relation between these components, and a new figure showing the compatibility of light bending and equivalence. A second analysis compares light bending near a neutron star for Schwarzschild and one alternate metric to evaluate feasibility of future experiments. Two methods of extension to non-light speed objects are discussed.
- Re-visiting the Anisotropy of Inertia Experiments (Advances in Astrophysics, vol 1, no 1, pp 47-53, July 2016) In the 1960s experiments investigating anisotropy of inertia relative to solar or galactic mass centers using the Mössbauer effect obtained negative results. Both sides of a debate over Mach’s Principle claimed the result was what should be expected. However in light of earlier comments by Einstein on the relativity of inertia to masses, Brans and Dicke felt a revised theory of gravity would better incorporate Mach’s Principle. We present a new view that the old experiment assumed, incorrectly, that Mach’s Principle affects only time dilation, which would violate the Equivalence Principle, and that the results were a predictable coordinate artifact. Using a special formalism of Distant Inertial and Spatially Homogeneous coordinates we give a plausible analysis that radial spatial distortion in a gravitational field is also related to Mach’s Principle and embodies the expected anisotropy while keeping equivalence locally intact. This leads to a view of momentum interactions via the space-time field that invites further analysis. Also, since Mach’s principle seems to be related to both time and spatial curvature, we briefly discuss whether it could be used as a postulate basis for space-time and how this might affect experiments designed to detect or exclude matter-coupled fields.
- Common pedagogical issues with de Broglie waves: moving double slits, composite mass and clock synchronization (Shuler, R.L., "Common Pedagogical Issues with De Broglie Waves: Moving Double Slits, Composite Mass, and Clock Synchronization," Physics Research International, Vol. 2015 (2015). - direct link to PDF) - This pedagogical paper suggests simple techniques for reference frame independent analysis of a moving double slit electron interference experiment, and a beat frequency heuristic for understanding de Broglie waves of composite particles such as neutrons and atoms. Points of similarity and difference between de Broglie and Schrödinger waves are explained. The necessity of momentum, energy and wavelength changes in the electrons in order for them to be vertically displaced in their own reference frame are shown to be required to make the double slit analysis work. A relativistic kinematic analysis of de Broglie frequency is provided showing how the higher de Broglie frequency of moving particles is consistent with Special Relativity and time dilation, and that it demonstrates a natural system which obeys Einstein's clock synchronization convention of simultaneity and no other. Students will be better prepared to identify practical approaches to solving problems, as well as to think about fundamental questions.
(click image to view animation of de Broglie's own "mechanical analogy")
- Leading Clocks Lag Phys. Ed., 51, 2 (2016) http://dx.doi.org/10.1088/0031-9120/51/2/025005 - A new memory aid for teaching the relativity of simultaneity is given that puts it on a par with "time dilation" and "length contraction" for quick and easy problem visualization. Guidelines for applicability of all three memory aids are given. As an example application the de Broglie wavelength is derived and dependence of de Broglie frequency on velocity explained in terms of Einstein synchronized reference frame measurements of a single clock (2 on 1) vs. measurements of an Einstein reference frame by an observer with a single clock (1 on 2).
- Is There a Gravitational Effect Which Is Analogous to Electrodynamic Induction? - by A. Einstein, 1912 - This important paper was not available in English and unknown in the English speaking world until the pubication of the posthumous complications of Einstein's papers in the 1970s. Thus it was overlooked by Sciama, Dicke and other important inertia researchers. It was until now still not available on the web and thus difficult to cite by modern standards, so I have re-keyed it and corrected some editorial problems. Einstein derives the same inertia as a summation of potential formula that other researchers have found, in a particularly concise manner without resorting to radiation or other controversial techniques. He uses an argument that is applicable to any theory of gravity which contains time dilation and other characteristics of modern gravity theories, thus this inertia is implicitly part of General Relativity and any of the various other metrical theories, without the need for specific formulation as for example in Brans-Dicke.
- The Twins-Clock Paradox History and Perspectives - (published in Journal of Modern Physics, very popular with many downloads, July 2014 DOI: 10.4236/jmp.2014.512108) - The twins or clock paradox has been a subject of lively discussion and occasional disagreement among both relativists and the public for over 100 years, and continues to attract physicists who write papers giving new analyses or defending old ones, even though many physicists now consider the matter only of educational interest. This paper investigates the number of papers, which is increasing, and trends in explanations, some of which are now targeted at professional physicists and other of which are targeted at optical or radar visualization rather than problem solving. Observations of students indicate the latest techniques help but only somewhat. An analysis is made of 21 previous treatments appearing in the education related American Journal of Physics, Einstein's discussions and several other pedagogical papers. A new memory aid for simultaneity transformation is given that puts it on a par with "time dilation" and "length contraction" for quick and easy problem visualization. The point of view of a trailing twin is introduced to show how simultaneity changes account for missing time in the turnaround. Length contraction is treated on equal footing with time dilation, and Swann's insight into clocks is extended to lengths. Treatments using the conventionality of simultaneity are seen as equivalent to choice of co-moving frames. Responses to difficult questions are suggested which avoid being dismissive, and engage students' critical thinking.
- A Fresh Spin on Newton's Bucket - (Published version in Physics Education vol. 50 no. 1 p. 88, 2015, short illustrated article suitable for high school or first semester physics students) An introduction to physics seems incomplete without the thought experiment known as Newton's Bucket. Doing so also introduces the famous historical critique of Newton by Mach, which inspired Einstein and spawned modern theories of gravity and the cosmos. The critique often fascinates and inspires students. But Mach's concept is not expressed in a simple algebraic way, which the students can analyze as easily as Newton's concepts. Recently that gap has been filled, and gives results which may have surprised Mach, and certainly will teach students how to think clearly about relative motion.
- On dynamics in a quasi-measurement field (Journal of Modern Physics Jan 2013 Vol. 4 No. 1) (needs updating for curved space-time) - A general theory of inertia tends to be circular because momentum and therefore inertia are taken as assumptions in quantum field theories. In this paper we explore instead using position uncertainty to infer inertia with mediation by quasi-measurement interactions. This method avoids attachment to the reference frame of the source masses and is thus completely relativistic, overcoming a conflict between historical theories of inertia and relativity. We investigate what laws of motion result, and whether natural explanations for equivalence and dark energy emerge.
ECONOMICS, ENGINEERING & SAFETY
- Isotropy, equivalence and the laws of inertia - (Physics Essays Dec 2011 Vol. 24 No. 4, pp 498-507) (Note: Discussions of light bending and full curvature metrics are superceded by the author's newer papers such as the one on "Numerical Geodesic Approximation...,"see above. ) Using equivalence to investigate gravitational time dilation, as Einstein once did, the laws of inertia are derived and it is shown that inertia is isotropic, in agreement with experiments based on the Mossbauer effect. Possible anisotropy of inertia should be removed as an objection to Mach's Principle. Additionally, a special non-physical condition on acceleration is derived which makes equivalence compatible with weak field effects (precession).
Tutorials & Working Papers:
Radiation Effects & Other Published Papers, Lead Author or principle innovator:
- Radiation Hardened By Design Standard Cell Library Techniques (tutorial - available by special arrangement only)
- Challenges in SET Measurement - (working paper)
- R. Shuler, B. Bhuva, B. Narasimham, Pulse Distortion in SET Measurements from Layout and Adjacent Signals
Note: IEEE may sometimes change links. If these links are broken, try searching on the title. If you do not have access to IEEE papers, request it from me on Academia.edu or ResearchGate.
Co-authored Papers:
- Configuration Tests of RHBD Library with DICE, TAG4, Dual Rail, TMR and New 10T Voting Latch using UMC 65 and XFAB 180 nm - (to be published Jan 2018 IEEE TNS) We describe heavy ion tests of RHBD configurations (varying guard timing, spacing, number of strings), including DICE, TAG4, TMR, I/O pads and a new 10T voting latch, to identify strategies for a portable nanoscale library. The TAG4, now off patent, provides superior performance to DICE. Large critical node separation requirements in bulk 65 nm are inferred. The new 10t voting latch performs as well as conventional TMR. A voting by block placement strategy demonstrates rapid reconfiguration for increased critical node group separation, and near optimal layout efficiency.
- Porting & Scaling Strategies for Nanoscale CMOS RHBD - (citation: Shuler, R.L., "Porting and Scaling Strategies for Nanoscale CMOS RHBD," Circuits and Systems I: Regular Papers, IEEE Transactions on, 62, 12, pp. 2856 - 2863 (2015). - pdf direct link - also available as presentation charts) Abstract: Techniques are described for minimizing the number of cells in a digital logic library, scaling and porting the cells to process nodes that do not nominally support scaling, and increasing the separation of critical node pairs without unduly disrupting the design process. A new compact modular 10T self-voting latch reduces circuitry by over half, allowing modular redundancy to approach theoretical efficiency limits. The result is allows investment in low volume designs, such as but not limited to radiation hardened by design (RHBD) applications for mission critical components, to provide returns over decades-long time periods.
- Real-Time Configurable Phase-Coherent Pipelines, with Dave Rutishauser, chapter 8, Embedded Systems, ed. Krzystof Iniewski, Wiley & Sons, Nov 2012
- Wide Range SET Pulse Measurement, with Li Chen, SEE Symposium, 2012
- Rapid Implementation of Floating-point Computations Using Phase-Coherent Dynamically Configurable Pipelines, presented at ERSA, July 2011
- SEU/SET Tolerant Phase Locked Loops in Radiation Effects in Semiconductors, ed. Krzysztof Iniewski, pp 305-324, CRC Press, Boca Raton FL, 2011
- SEE Tolerant Self-Calibrating Simple Fractional-N PLL, SEE Symposium, 2010
- Comparison of Dual-Rail and TMR Logic Cost Effectiveness and Suitability for FPGAs with Reconfigurable SEU Tolerance, NSREC 2008, IEEE Transactions on Nuclear Science Feb. 2009
- Fault Tolerant FPGA Reconfigurable Hardware Architecture, MAPLD 2008 (presentation)
- The Effectiveness of TAG or Guard-Gates in SET Suppression Using Delay and Dual-Rail Configurations at 0.35 um, NSREC 2006, IEEE Transactions on Nuclear Science Deb. 2006
- SEU Performance of TAG Based Flip-Flops, NSREC 2005, IEEE Transactions on Nuclear Science Dec. 2005
- Improved Discrete Approximation of Laplacian of Gaussian, NASA Tech Briefs, March 2004
- Switched RC Multi-pole Filter, 8th NASA Symposium on VLSI Design, 1999
- Single-Chip Instrumentation Module for Radiation Environment, 7th NASA Symposium on VLSI Design, 1998
- Efficient Real-Time Garbage Collection for LISP, First Annual Workshop on Robotics and Expert Systems, NASA/JSC, 1985
Patents:
- Gadlage, et. al., Temperature Dependence of Digital Single-Event Transients in Bulk and Fully-Depleted SOI Technologies, NSREC 2009
- Narasimham, Gambles, et. al., Quantifying the Effect of Guard Rings and Guard Drains in Mitigating Charge Collection and Charge Spread, NSREC 2008, IEEE TNS Dec. 2008
- Narasimham, et. al., Quantifying the Reduction in Collected Charge and Soft Errors in the Presence of Guard Rings, IEEE Trans. on Device and Materials Reliability, March 2008
- Narasimham, et. al., Quantifying the Effectiveness of Guard Bands in Reducing the Collected Charge Leading to Soft Errors, Reliability physics symposium, 2007. proceedings. 45th annual. IEEE
- Balasubramanian, et. al., A Built-In Self-Test (BIST) Technique for Single-Event Testing in Digital Circuits, NSREC 2008, IEEE TNS Dec. 2008
- Abbott, et. al., Avionics for a Small Satellite, AIP Space Technology and Applications International Forum - 2001
- Ellenberger, et. al., Automatic Generation of Real-Time Ada Simulations for Space Station Freedom, Society for Computer Simulation, Nov. 1993
Unofficial Interests:
- Methods and circuitry for reconfigurable SEU/SET tolerance, 7,859,292 B1, Dec 2010
- Auto-routable, configurable, daisy chainable data acquisition system, 6,943,621 Sep. 2005
- Practical active capacitor filter, 6,943,619 Sep. 2005
- Low offset rail-to-rail operational amplifier, 20060097791 A1, with Scott Askew, published May 2006, I do not remember the deal with this, whether no claims were allowed or it was too expensive, but it is cited by several subquent patents as prior art
- Method for evaluating and recommending digital image print size with ordering and overlapped file upload, 20050162670 A1, published Jul 2005 with claim allowed, but too expensive to file - cited in several subquent patents as prior art
- Method and apparatus for reducing the vulnerability of latches to single event upsets, 6,492,857 Dec 2002 (TAG / Guard Gate patent)
- Method and apparatus for reducing the vulnerability of latches to single event upsets, 6,377,097 April 2002 (compact delay patent)
- Real-time garbage collection for list processing using restructured cells for increased reference counter size, 4,912,629 March 1990
- Inertia and gravity as a result of quasi-measurement fields (position-momentum quantum fields, instead of the usual energy-time fields), and associated implications for dark energy.
- Limits on superposition and a resolution of the "measurement problem" in quantum mechanics based on the uncertainty principle.
- Sociology of highly reliable systems: crash rate theorem holds that malfunction costs are in equilibrium with utility. Not only does lowering malfunction costs result in more malfunctions, but perversely, improving reliability increases utility, and therefore also malfunction (accident) costs! Making a system safer may mean more people are killed by it in the long run.
- Economics and investing: non-linear market theory examines the effect of non-independence of returns on diversification and risk,and the long term outcome and social implications of growth vs. dividend strategies.
- Interpretation of folktales and myth: particularly the origin of family and religion, the marriage of Venus to Vulcan, and the true role of Venus in the legend of Cupid and Psyche.