Rockwell Automation (United States)

In 1997, Azuma published a survey on augmented reality (AR). Our goal is to complement, rather than replace, the original survey by presenting representative examples of the new advances. We refer one to the original survey for descriptions of potential applications (such as medical visualization, maintenance and repair of complex equipment, annotation, and path planning); summaries of AR system characteristics (such as the advantages and disadvantages of optical and video approaches to blending virtual and real, problems in display focus and contrast, and system portability); and an introduction to the crucial problem of registration, including sources of registration error and error-reduction strategies.

The overall mean recognition probability (mean accuracy) of a pattern classifier is calculated and numerically plotted as a function of the pattern measurement complexity n and design data set size <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</tex> . Utilized is the well-known probabilistic model of a two-class, discrete-measurement pattern environment (no Gaussian or statistical independence assumptions are made). The minimum-error recognition rule (Bayes) is used, with the unknown pattern environment probabilities estimated from the data relative frequencies. In calculating the mean accuracy over all such environments, only three parameters remain in the final equation: <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n, m</tex> , and the prior probability <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p_{c}</tex> of either of the pattern classes. With a fixed design pattern sample, recognition accuracy can first increase as the number of measurements made on a pattern increases, but decay with measurement complexity higher than some optimum value. Graphs of the mean accuracy exhibit both an optimal and a maximum acceptable value of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</tex> for fixed <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p_{c}</tex> . A four-place tabulation of the optimum <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</tex> and maximum mean accuracy values is given for equally likely classes and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</tex> ranging from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1000</tex> . The penalty exacted for the generality of the analysis is the use of the mean accuracy itself as a recognizer optimality criterion. Namely, one necessarily always has some particular recognition problem at hand whose Bayes accuracy will be higher or lower than the mean over all recognition problems having fixed <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n, m</tex> , and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p_{c}</tex> .

We present an efficient method for estimating cluster centers of numerical data. This method can be used to determine the number of clusters and their initial values for initializing iterative optimization-based clustering algorithms such as fuzzy C-means. Here we use the cluster estimation method as the basis of a fast and robust algorithm for identifying fuzzy models. A benchmark problem involving the prediction of a chaotic time series shows this model identification method compares favorably with other, more computationally intensive methods. We also illustrate an application of this method in modeling the relationship between automobile trips and demographic factors.

A new definition for work of adhesion Wa is applied to computationally define the dispersion γs d and polar γs d components of the solid surface tension γs = γs d + γs d for twenty-five low energy substrates. These calculated surface properties are correlated with surface composition and structure. Surface dipole orientation and electron induction effects are respectively distinguished for chlorinated and partially fluorinated hydrocarbons. Published values for critical surface tension of wetting γc are correlated with both γs d and γs.

A highly precise method for locating the valence-band edge in x-ray photoemission spectra is reported. The application to measuring semiconductor interface potentials is discussed. X-ray photoemission-spectroscopy experiments on Ge and GaAs(110) crystals have given Ge $3d$, Ga $3d$, and As $3d$ core level to valence-band edge binding-energy differences of 29.55, 18.81, and 40.73 eV to a precision of \ifmmode\pm\else\textpm\fi{}0.02 eV. For illustration, the valence-band discontinuity at an abrupt Ge/GaAs(110) heterojunction is determined to be 0.53\ifmmode\pm\else\textpm\fi{}0.03 eV.

1. General Information. 2. Linear Dynamic Systems. 3. Random Processes and Stochastic Systems. 4. Linear Optimal Filters and Predictors. 5. Nonlinear Applications. 6. Implementation Methods. 7. Practical Considerations. Appendix A: Software. Appendix B: A Matrix Refresher.

Operation of a phase locked loop (PLL) system under distorted utility conditions is presented. A control model of the PLL system is developed and recommendations are made on tuning of this model specially for operation under common utility distortions such as line notching, voltage unbalance/loss, and frequency variations. The PLL is completely implemented in software without any filters. All analytical results are experimentally verified.

The problem of wave-front estimation from wave-front slope measurements has been examined from a least-squares curve fitting model point of view. It is shown that the slope measurement sampling geometry influences the model selection for the phase estimation. Successive over-relaxation (SOR) is employed to numerically solve the exact zonal phase estimation problem. A new zonal phase gradient model is introduced and its error propagator, which relates the mean-square wave-front error to the noisy slope measurements, has been compared with two previously used models. A technique for the rapid extraction of phase aperture functions is presented. Error propagation properties for modal estimation are evaluated and compared with zonal estimation results.

In this article we shall present a summary of the various stochastic approaches and applications to chemical reaction kinetics, but before discussing these we first briefly introduce the basic ideas and definitions of classical or deterministic chemical kinetics. One of the basic questions to which chemists address themselves is the rate of chemical reactions, or in other words, how long it takes for a chemical reaction to attain completion, or equilibrium. Apparently the first significant quantitative investigation was made in 1850 by L. Wilhelmy [93]. He studied the inversion of sucrose (cane sugar) in aqueous solutions of acids, whose reaction is He found empirically that the rate of decrease of concentration of sucrose was simply proportional to the concentration remaining unconverted, i.e., if S ( t ) is the concentration of sucrose, then The constant of proportionality is called the rate constant of the reaction. If S o is the initial concentration of sucrose, then Since then an enormous number of reactions has been studied and the field of chemical kinetics is now one of the largest areas of chemical research. The importance of the field lies in the fact that it yields concise expressions for the time dependence of reactions, predicts yields, optimum economic conditions, and gives one much insight into the actual molecular processes involved. The detailed molecular picture of a reaction process is called the mechanism of the reaction.

Operation of a three phase-phase locked loop-system under distorted utility conditions is presented. A control model of the PLL system is developed and and used for time and frequency domain analysis, and recommendations are made on tuning of this model specially for operation under common utility distortions as: line notching, voltage unbalance/loss, frequency variations. The PLL is completely implemented in software. All analytical results are experimentally verified.

A new mathematical model of the power circuit of a three-phase voltage source converter (VSC) was developed in the stationary and synchronous reference frames. The mathematical model was then used to analyze and synthesize the voltage and current control loops for the VSC. Analytical expressions were derived for calculating the gains and time constants of the current and voltage regulators. The mathematical model was used to control a 140-kW regenerative VSC. The synchronous reference-frame model was used to define feedforward signals in the current regulators to eliminate the cross coupling between the d and q phases. It allowed the reduction of the current control loops to first-order plants and improved their tracking capability. The bandwidths of the current and voltage-control loops were found to be approximately 20 and 60 times (respectively) smaller than the sampling frequency. All control algorithms were implemented in a digital signal processor. All results of the analysis were experimentally verified.

This paper provides analytical and graphical methods for the study, performance evaluation and design of the modern carrier-based pulse width modulators (PWMs), which are widely employed in PWM voltage-source inverter (VSI) drives. Simple techniques for generating the modulation waves of the high-performance PWM methods are described. The two most important modulator characteristics-the current ripple and the switching losses-are analytically modeled. The graphical illustration of these often complex multivariable functions accelerate the learning process and help one understand the microscopic (per-carrier cycle) and macroscopic (per fundamental cycle) behavior of all the modern PWM methods. The analytical formulae and graphics are valuable educational tools. They also aid the design and implementation of the high-performance PWM methods.

One of the early projects established by CODATA was intended to provide a recommended set of the fundamental physical constants, which are so important to the analysis and interpretation of experimental data in many scientific disciplines. The first "Recommended Consistent Values of the Fundamental Physical Constants" appeared in 1973 and was subsequently adopted by most international and national bodies in their own recommendations. This process has contributed to improved compatibility of scientific and technical data in all fields of science. CODATA presents here a revised version of these recommendations which takes into account the significant advances in metrology that have occurred since the 1973 analysis. "The 1986 adjustment of the fundamental physical constants" represents a 5-year effort involving experts from the major metrological laboratories of the world. It is hoped that this recommended data set will receive the acceptance of the scientific community which was achieved by its predecessor.

This paper presents a review of both active and passive ring laser devices. The operating principles of the ring laser are developed and discussed, with special emphasis given to the problems associated with the achievement of greater sensitivity and stability. First-principle treatments of the nature of quantum noise in the ring laser gyro and various methods designed to avoid low-rotation-rate lock-in are presented. Descriptions of state-of-the-art devices and current and proposed applications (including a proposed test of metric theories of gravity using a passive cavity ring laser) are given.

The history and fundamentals of distributed arithmetic (DA) are presented. Ways to increase the speed of DA multiplication are described. DA is applied to a biquadratic digital filter, providing an example of vector dot-product and vector-matrix-product mechanization. Applications to transformers and nonlinear and/or nonstationary processing with DA are discussed. It is seen that DA is a very efficient means to mechanize computations that are dominated by inner products.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The collection of charge from ion tracks can produce logic upset and memory change in high density integrated circuits. It has been experimentally observed that drift conduction usually plays a dominant role when the ion track penetrates a junction. The first charge collection analysis concentrated on the diffusion conduction process. A recent analysis emphasizes drift conduction and describes the "funnel" which produces drift collection from the substrate. The funneling phenomenon has been modelled using two-dimensional computer simulations. It is extremely desirable to develop analytical solutions tp better understand the problem and to provide the basis for modelling the effect in circuit and system analysis computer codes such as SYSCAP. This paper develops an approximate analytic solution expressed as I(t) = Io [exp(-αt) - exp (-ßt)] (1) where Io is approximately the maximum current, 1/β is the collection time constant of the junction, and 1/ß is the time constant for initially establishing the ion track. The junction time constant is shown to be Kεo/qμND, and it increases slowly with funnel length when a funnel is present. The analysis shows that the excess carriers move almost exclusively by ambipolar diffusion for very early times, and that the fields present in semiconductor devices, including p-n junction fields, collapse. Ambipolar diffusion proceeds until the excess carrier concentration is reduced to approximately the background doping density at which time the junction field is restored and the carriers move by drift.

In this paper we describe the current state of the DARPA packet radio network. Fully automated algorithms and protocols to organize, control, maintain, and move traffic through the packet radio network have been designed, implemented, and tested. By means of protocols, networks of about 50 packet radios with some degree of nodal mobility can be organized and maintained under a fully distributed mode of control. We have described the algorithms and illustrated how the PRNET provides highly reliable network transport and datagram service, by dynamically determining optimal routes, effectively controlling congestion, and fairly allocating the channel in the face of changing link conditions, mobility, and varying traffic loads.

This paper is a summary of the 1973 least-squares adjustment of the fundamental physical constants carried out by the authors under the auspices of the CODATA Task Group on Fundamental Constants. The salient features of both the input data used and its detailed analysis by least-squares are given. Also included is the resulting set of best values of the constants which is to be recommended for international adoption by CODATA, a comparison of several of these values with those resulting from recent past adjustments, and a discussion of current problem areas in the fundamental constants field requiring additional research.

Immittance, transfer, and scattering characteristics are studied for acoustic surface wave transducers of the interdigital electrode form. Linear network models are used to represent the transducer as a chain of identical three-ports which are acoustically in cascade but electrically in parallel. Transducer operation at acoustic synchronism is described theoretically and compared to current experimental data for transducers operating at 100 MHz and fabricated on lithium niobate. Favorable lithium niobate configurations for efficient, broad-band transducer operation are given. Scattering characteristics as a function of electric load are discussed. Low values of acoustic reflection loss are predicted theoretically and observed experimentally when the electric load and transducer capacitance are in resonance. The frequency dependence of transducer radiation immittance is studied, and the response is found to be analogous to the response of an endfire antenna array.

A study of heterojunction interface geometry based on our measured differences in $3d$ core-state binding energies for germanium and gallium at Ge-GaAs heterojunctions of different crystallographic orientations is reported. For the interfaces which have been studied, i.e., (110), (100) Ga, (100) As, (111) Ga, and ($\overline{1}\overline{1}\overline{1}$) As, orientation-dependent variations in dipole contributions to valence-band discontinuities of about 0.2 eV have been observed. From electrostatic considerations we deduce the simplest interface geometries consistent with the facts that the differences are small and no large charge accumulations can occur at the junction. An abrupt planar junction is allowed for the (110) interface, but the polar interfaces require at least two transition planes of atoms with compositions which are deduced from the two conditions above. The electrostatic calculations were based upon the differences in nuclear charge and are unaffected by the resulting polarization of the bonds if that polarization is described in an "electronegativity" approximation. In this approximation there would in fact be no dipole shift for the ideal geometries proposed. An improved treatment of the bond polarization based upon the bond-orbital model gives residual dipole shifts somewhat smaller than those observed, and in poor agreement with our measurements. Inclusion of lattice-distortion effects at the interface also fails to account for the observed dipole shifts. We conclude that the experimentally prepared junctions must contain deviations from the ideal atom arrangements. The number of these deviations required to account for the observed shifts is on the order of one for every fifteen interface atoms.