Showing papers by "Rensselaer Polytechnic Institute published in 1977"
TL;DR: A method for detecting sharp "corners" in a chain-coded plane curve is described and a measure for the prominence ("cornerity") of a corner is introduced.
Abstract: A method for detecting sharp "corners" in a chain-coded plane curve is described. A measure for the prominence ("cornerity") of a corner is introduced. The effectiveness of the method is illustrated by means of a number of examples.
531 citations
TL;DR: The reduced update Kalman filter is shown to be optimum in that it minimizes the post update mean-square error (mse) under the constraint of updating only the nearby previously processed neighbors.
Abstract: The Kalman filtering method is extended to two dimensions. The resulting computational load is found to be excessive. Two new approximations are then introduced. One, called the strip processor, updates a line segment at a time; the other, called the reduced update Kalman filter, is a scalar processor. The reduced update Kalman filter is shown to be optimum in that it minimizes the post update mean-square error (mse) under the constraint of updating only the nearby previously processed neighbors. The resulting filter is a general two-dimensional recursive filter.
347 citations
TL;DR: Algorithms are described for extracting critical points of shape description in the presence of noise and an illustration is given showing how the critical points may be used in the development of a shape description system.
180 citations
TL;DR: A stochastic model of edge structure is proposed and the edge detection problem formulated as one of least mean-square spatial filtering, which indicates substantial advantages over conventional edge detectors in the presence of noise.
127 citations
TL;DR: The optimal control strategy with state variable constraints is studied and a numerical solution method is proposed for determining the optimal control for the case in which the intersection demand is predictable for the entire control period.
126 citations
TL;DR: In this paper, singular stress and strain fields are found at the tip of a crack growing steadily and quasi-statically into an elastic-plastic strain-hardening material, characterized by J2 flow theory together with a bilinear effective stress-strain curve.
Abstract: Singular stress and strain fields are found at the tip of a crack growing steadily and quasi-statically into an elastic-plastic strain-hardening material. The material is characterized byJ2 flow theory together with a bilinear effective stress-strain curve. The cases of anti-plane shear, plane stress and plane strain are each considered. Numerical results are given for the order of the singularity, details of the stress and strain-rate fields, and the near-tip regions of plastic loading and elastic unloading.
124 citations
TL;DR: In this paper, a van der Pol relaxation oscillator that is subjected to external sinusoidal forcing can exhibit stable and unstable periodic and almost periodic responses, and it even happens that two stable subharmonics having different periods may coexist.
Abstract: : A van der Pol relaxation oscillator that is subjected to external sinusoidal forcing can exhibit stable and unstable periodic and almost periodic responses. For some forcing amplitudes it even happens that two stable subharmonics having different periods may coexist. The stable responses of such forced oscillators are investigated. By numerically computing the rotation number of stable oscillations for various values of the forcing amplitude and oscillator tuning, descriptions are obtained of regions of phase locking, successive bifurcation of stable subharmonic and almost periodic oscillations, and overlap regions where two distinct stable oscillations can coexist.
101 citations
01 Apr 1977
TL;DR: In this paper, a van der Pol relaxation oscillator that is subjected to external sinusoidal forcing can exhibit stable and unstable periodic and almost periodic responses, and it even happens that two stable subharmonics having different periods may coexist.
Abstract: : A van der Pol relaxation oscillator that is subjected to external sinusoidal forcing can exhibit stable and unstable periodic and almost periodic responses. For some forcing amplitudes it even happens that two stable subharmonics having different periods may coexist. The stable responses of such forced oscillators are investigated. By numerically computing the rotation number of stable oscillations for various values of the forcing amplitude and oscillator tuning, descriptions are obtained of regions of phase locking, successive bifurcation of stable subharmonic and almost periodic oscillations, and overlap regions where two distinct stable oscillations can coexist.
88 citations
TL;DR: This work generalizes many of the results on efficient points for linear multiple objective optimization problems to the nonlinear case by focusing on an auxiliary problem by relying on duality theory.
Abstract: We generalize many of the results on efficient points for linear multiple objective optimization problems to the nonlinear case by focusing on an auxiliary problem. The approach, which relies on duality theory, is a straightforward development that even in the linear case yields simpler proofs.
81 citations
TL;DR: It is shown that coordination of the signals, according to analytical relationships developed here, is necessary for optimal operation and it is demonstrated that the entire congestion period must be divided into two intervals and that the optimal control in both intervals is determined by considering separate test functions.
78 citations
TL;DR: It has been determined that the nonlinear interaction between the hydraulic permeability of the tissue and the compressive strain on the tissue retards the progress of the consolidation of the cartilage during uniaxial compression.
TL;DR: Data suggest that apolar interactions plus disulfide bonds may be important in stabilizing the deposit structure, and point to improved cleaning procedures.
Abstract: Formation of opaque deposits on the anterior (air) surface of hydrophilic soft contact lenses is a problem worthy of investigation by all concerned. These deposits have been analyzed for biomaterials by chemical, biochemical, electrophoretic, and immunological techniques. Qualitative and quantitative chemical colorimetric tests revealed the presence of variable amounts of protein (5-10 microgram/lens), carbohydrate (1.0-1.2 microgram/lens), and phospholipids (0.01-0.05 micronmole/lens). Cholesterol and glucose were not present at detectable levels. Fluorescent antibody tests with appropriate controls gave positive tests for albumin, lysozyme, gamma-G-globulin, and alpha1-lipoprotein in the deposits, all proteins present in tear fluid. Deposits were most effectively removed from the lenses by the combination of heat, sodium dodecyl sulfate (SDS) detergent, and the thiol reagent dithiothreitol (DTT). SDS-denatured protein migrated on polyacrylamide gels with electrophoretic patterns corresponding to molecular weights for those proteins detected by the above antibody tests. The nature of the bonding interactions of biomaterials to the lenses was probed by chemical reagents used to remove them, employed singly and in all possible combinations. Urea, guanidine hydrochloride, potassium thiocyanate, potassium perchlorate, hydroxylamine, and EDTA were much less effective than SDS and DTT. These data suggest that apolar interactions plus disulfide bonds may be important in stabilizing the deposit structure, and point to improved cleaning procedures.
TL;DR: In this paper, the effect of austenite prestrain above the md temperature on the structure and transformation kinetics of the martensitic transformation observed on cooling was determined for a series of Fe-Ni-Cr-C alloys.
Abstract: The effect of austenite prestrain above theMd temperature on the structure and transformation kinetics of the martensitic transformation observed on cooling was determined for a series of Fe-Ni-Cr-C alloys. The alloys exhibited a shift in martensite morphology in the nondeformed state from twinned plate to lath while theMs temperature, carbon content, and austenite grain size were constant. The transformation behavior was observed over the temperature range 0 to -196°C as a function of tensile prestrains performed above theMd temperature. A range of prestrains from 5 pct to 45 pct was investigated. It is concluded that the response of a given alloy to austenite prestrain above theMd temperature can be correlated with the morphology of the martensite observed in the nondeformed, as-quenched state. For the range of prestrains investigated, the transformation of austenite to lath martensite is much more susceptible to stabilization by austenite prestrain above theMd temperature than is the transformation of austenite to plate martensite.
TL;DR: In this article, the problem of generating the efficient set of locations for a single facility where it is important that the facility be located as close as possible to each of a number of existing facilities whose locations are known is considered.
Abstract: Much of the literature involving the location of one or more new facilities in the plane is concerned with minimizing a single objective function. In this paper we consider the problem of generating the efficient set of locations for a single facility where it is important that the facility be located as close as possible to each of a number of existing facilities whose locations are known. We concentrate on the notion of distance commonly referred to as the l1 norm, the Manhattan norm, or the city-block norm but results for other norms are given also. We develop properties of the efficient set and present two separate procedures for generating the efficient set.
TL;DR: In this article, the authors derived the differential equations and boundary conditions describing the behavior of a finitely deformable, heat-conducting composite material by means of a systematic application of the laws of continuum mechanics to a well-defined macroscopic model consisting of interpenetrating solid continua.
Abstract: The differential equations and boundary conditions describing the behavior of a finitely deformable, heat-conducting composite material are derived by means of a systematic application of the laws of continuum mechanics to a well-defined macroscopic model consisting of interpenetrating solid continua. Each continuum represents one identifiable constituent of the N-constituent composite. The influence of viscous dissipation is included in the general treatment. Although the motion of the combined composite continuum may be arbitrarily large, the relative displacement of the individual constituents is required to be infinitesimal in order that the composite not rupture. The linear version of the equations in the absence of heat conduction and viscosity is exhibited in detail for the case of the two-constituent composite. The linear equations are written for both the isotropic and transversely isotropic material symmetries. Plane wave solutions in the isotropic case reveal the existence of high-frequency (optical type) branches as well as the ordinary low-frequency (acoustic type) branches, and all waves are dispersive. For the linear isotropic equations both static and dynamic potential representations are obtained, each of which is shown to be complete. The solutions for both the concentrated ordinary body force and relative body force are obtained from the static potential representation.
TL;DR: In this paper, the authors propose a block-iterative method for solving linear complementarity problems with finite-length journal bearings, where the subproblems arise in the process of making discrete approximations to differential equations with special side conditions.
Abstract: This paper delineates the underlying theory of an efficient method for solving a class of specially-structured linear complementarity problems of potentially very large size. We propose a block-iterative method in which the subproblems are linear complementarity problems. Problems of the type considered here arise in the process of making discrete approximations to differential equations in the presence of special side conditions. This problem source is exemplified by the free boundary problem for finite-length journal bearings. Some of the authors' computational experience with the method is presented.
TL;DR: Therapists generally found their more assertive patients to be happier, more active, and more strong-willed, suggesting that assertion training may be a useful treatment modality for depression.
TL;DR: Experimental results for a phase-shift keyed (PSK) signal embedded in unwanted interference is presented and the relative advantages of SAW technology with respect to other technologies such as charge coupled devices is discussed.
Abstract: In this paper, various potential implementations of spread spectrum systems using surface acoustic wave (SAW) devices are discussed and experimental results for a phase-shift keyed (PSK) signal embedded in unwanted interference is presented. An overview of acoustic surface wave technology as it applies to signal processing in spread spectrum communication systems is presented. The ability to implement most of the basic elements of such systems using SAW devices is discussed, with emphasis on the space charge coupled convolver and Fourier transformer. SAW implementation of a fairly general block diagram applicable to a variety of signal and interference situations is described, and the relative advantages of SAW technology with respect to other technologies such as charge coupled devices is discussed.
TL;DR: The thermal expansion of GeS has been studied above room temperature up to the melting point of 658 ± 5°C by X-ray diffraction techniques using a 190 mm diameter Unicam high temperature camera as discussed by the authors.
Abstract: The thermal expansion of GeS has been studied above room temperature up to the melting point of 658 ± 5°C by X-ray diffraction techniques using a 190 mm diameter Unicam high temperature camera. The thermal expansion of the crystallographic axes is linear with distinct changes in the rate of expansion at about 250°C, 370°C and 510°C. No first-order structural transformation was observed for this system up to the melting point. The results of additional studies on GeTe are in general agreement with those of others and confirm trends in the thermal expansion behavior of the germanium monochalcogenide series.
Die thermische Ausdehnung des GeS und GeTe
Die thermische Ausdehnung des GeS wurde rontgenographisch mittels einer 190 mm Unicam Hochtemperaturkamera von Zimmertemperatur bis zum Schmelzpunkt von 658 ± 5°C untersucht. Die thermische Ausdehnung der kristallographischen Achsen ist linear mit betonten Anderungen der Ausdehnungskoeffizienten bei ungefahr 250°C, 350°C und 510°C. Eine Strukturumwandlung erster Ordnung wurde fur diese. Verbindung bis zum Schmelzpunkt nicht beobachtet. Die Ergebnisse zusatzlicher Messungen am GeTe stimmen mit denen anderer uberein und bestatigen den Trend im thermischen Ausdehnungsverhalten der Germaniummonochalkogenide.
TL;DR: The interaction of ethylene gas with a Ni(110) surface has been studied by a combination of modulated beam mass spectrometry and Auger electron spectroscopy techniques.
TL;DR: In this paper, a three-layer model of articular cartilage is used to model the flow and deformational behavior of the articular surface. But the model is not suitable for the analysis of all the known histological, ultrastructural, and biomechanical variations of the tissue properties.
Abstract: Fluid flow and mass transport mechanisms associated with articular cartilage function are important biomechanical processes of normal and pathological synovial joints. A three-layer permeable, two-phase medium of an incompressible fluid and a linear elastic solid are used to model the flow and deformational behavior of articular cartilage. The frictional resistance of the relative motion of the fluid phase with respect to the solid phase is given by a linear diffusive dissipation term. The subchondral bony substrate is represented by an elastic solid. The three-layer model of articular cartilage is chosen because of the known histological, ultrastructural, and biomechanical variations of the tissue properties. The calculated flow field shows that for material properties of normal healthy articular cartilage the tissue creates a naturally lubricated surface. The movement of the interstitial fluid at the surface is circulatory in manner, being exuded in front and near the leading half of the moving surface load and imbibed behind and near the trailing half of the moving load. The flow fields of healthy tissues are capable of sustaining a film of fluid at the articular surface whereas pathological tissues cannot.
TL;DR: In this article, the preparation and characterization of single-phase sintered ceramic materials based on Y2O3-stabilized ZrO2 with oxides of Ti, Zn, Ce, Cr, Mn, and U/Fe as third-component additives are described.
Abstract: The preparation and characterization of single-phase sintered ceramic materials based on Y2O3-stabilized ZrO2 with oxides of Ti, Zn, Ce, Cr, Mn, and U/Fe as third-component additives are described. These materials were prepared for a process to produce high-purity hydrogen and were evaluated for this process via measurements of electrical conductivity, stability, and transport number. Compositions with oxides of Ce and Cr in Y2O3-stabilized ZrO2 are shown to be the most promising candidates.
TL;DR: In this paper, the generality of the behaviour pattern makes it possible to predict foam behaviour of systems for which phase diagrams or solubilities are known. But the authors do not consider the case where phase diagrams are not available.
Abstract: The portions of phase diagrams near the critical point of a phase separation denote compositions that show dramatic contrasts in foam behavior. Homogeneous solutions containing two or three components show foaminess at concentrations near those at which a phase separation occurs, with maximum foaminess near the critical-solution point. Defoaming occurs in heterogeneous systems consisting of conjugate solutions, especially near critical-solution points. Analogous behaviour is shown by polymer solutions, for which the place of a phase diagram is supplied by solubility parameters. The generality of the behaviour pattern makes it possible to predict foam behaviour of systems for which phase diagrams or solubilities are known.
TL;DR: In this article, the authors incorporate job relevance into the weighting procedure via job analysis and inject the "hand of reason" into the process to ensure job-relatedness as well as validity.
Abstract: The use of the standard weighted application procedure relies on strictly empirically derived keys for validity. While weighted applications are generally valid in terms of the correlation between score on the application and position on the criterion, the empirical scheme may weight items that can not be shown to be relevant to the job for which they predict. To the extent that employment decisions are based on non-job-relevant weighted applications, such decisions may be contrary to the letter or the spirit of the Civil Rights Act. Alternative methods incorporating job relevance into the weighting procedure via job analysis inject the “hand of reason” into the process. Such rational-empirical approaches ensure job-relatedness as well as validity.
TL;DR: In this paper, a theory is presented for predicting the maximum spoutable height, in a spouted bed where fluidization of the annular solids limits the penetration of the fluid jet entering the bed.
Abstract: A theory is presented for predicting the maximum spoutable height, in a spouted bed where fluidization of the annular solids limits the penetration of the fluid jet entering the bed.
The quantity (Hmds/(D – d) is found to be a function of ds/Dc only for spherical particles and
\[ \frac{{H_m d_S }} {{(D_c^2 - d_S^2 )}} = 0.345\left( {\frac{{d_S }} {{D_c }}} \right)^{ - 0.384} \]
where the spout diameter is calculated using McNab's correlation(7). Insertion of McNab's correlation into Equation (1) shows that Hm is proportional to D and the effect of dp on Hm varies from d to d as the particle Reynolds number increases assuming 1 ≥ (ds/D).
Using experimental value of ds, the calculated values of Hm differ from the experimental ones by 8.5% on average.
When small particles are spouted with air, the penetration of the jet is limited by the formation of a slug in he spout and the theoretical value provides an upper limit for Hm.
On presente une theorie pour prevoir la hauteur maximale giclable dans un lit soumis a un jet fluide et dans lequel la fluidisation des solides annulaires limite la penetration dudit jet dans la lit.
On a trouveque la quantite (Hmds/(D – d) n'etait fonction de ds/Dc que pour les particules spheriques et l'expression suivante:
\[ \frac{{H_m d_S }} {{(D_c^2 - d_S^2 )}} = 0.345\left( {\frac{{d_S }} {{D_c }}} \right)^{ - 0.384} \]
dans laquelle on calcule le diametre dela giclee en employant la correlation de McNab(7). En inserant la correlation de McNab dans l'equation (1), on constate que Hm est proportionnelle a D et que l'effet de dp sur Hm varie entre d et d, lorsque le nombre de Reynolds s'accroǐt, en supposant que 1 est ≥ (ds/D).
En employant les valeurs experimentales de ds, les valeurs calculees de Hm different en moyenne de 8.5% des valeurs experimentales.
Lorsqu'on soumet des petites particules a un jet d'air, la penetration de celui-ci est limitee par la formation d'un “barreau” (slug) dans le goulot et la valeur theorique fournit une limite superieure pour Hm.
TL;DR: In the early years of radio, the structure of the industry changed repeatedly with every innovation in apparatus or circuitry, a situation that led, as Professor Reich shows, to heavy investment in non-productive research as discussed by the authors.
Abstract: The advent of high-technology industries around the turn of the century created the modern industrial research department and placed a new emphasis upon the search for patentable innovations. While some of this research led to advances in basic scientific knowledge, and much of it produced product or process improvements that were directly applicable to a firm's business, a great deal was undertaken to enhance firms' bargaining powers with each other in order to preserve monopoly positions. In the early years of radio, the structure of the industry changed repeatedly with every innovation in apparatus or circuitry, a situation that led, as Professor Reich shows, to heavy investment in “non-productive” research.
TL;DR: In this paper, the melting or plasticating behavior of seven commercial polymers (high density polyethylene, low density polymethylene, polypropylene, polyoxymethylene copolymer, polystyrene, poly(methyl methacrylate), and polycarbonate (PC) was investigated using an experimental apparatus specifically designed to measure the melting rate and the viscous shear stress of a solid polymer on a steel surface under precisely controlled conditions of temperature, velocity, pressure and sample width comparable to actual processing.
Abstract: The melting or plasticating behavior of seven commercial polymers (high density polyethylene, low density polyethylene, polypropylene, polyoxymethylene copolymer, polystyrene, poly(methyl methacrylate), and polycarbonate (PC) was investigated using an experimental apparatus specifically designed to measure the melting rate and the viscous shear stress of a solid polymer on a steel surface under precisely controlled conditions of temperature, velocity, pressure and sample width comparable to actual processing. The melting rate (per unit polymer solid/metal contact area) was found to increase with increasing temperature for all polymers except PC, to decrease with increasing sample width and to increase less than proportionally to velocity. Pressure increased the melting rate somewhat for most of the polymers. The viscous shear stress decreased with increasing temperature for all polymers except PC, decreased with increasing sample width and increased with increasing velocity. Pressure generally increased the viscous shear stress. PC showed an unusual behavior with a maximum in the melting rate near 4200°F(215.5°C) and also a maximum in the viscous shear stress near 445°F (229.4°C). The present melting model could be examined unequivocally for the first time using our experimental results. Comparison of our experimental results with the predictions of the present melting model clearly indicates the inadequacy of the present melting model, Our experimental results will provide a basis for rational development of a reliable melting model.
TL;DR: Two studies are reported which demonstrate that in delayed alternation the spatial factor, though essential, serves primarily the sequential aspects of the task.
TL;DR: In this article, large activation energy asymptotics are employed to study one-dimensional, steady laminar flame propagation involving a sequential two-step reaction A → B → C. The response of the system is presented in terms of a graph for the burning rate M as a function of the Damkohler numbers D1 and D2 of the two reactions.
TL;DR: In this article, a peer rating approach is used to measure innovation and productivity in R&D productivity, and a peer-rated approach is proposed to evaluate the quality of a product.
Abstract: (1977). Improving R&D Productivity: Measuring Innovation and Productivity — A Peer Rating Approach. Research Management: Vol. 20, No. 1, pp. 35-38.