Showing papers by "Rensselaer Polytechnic Institute published in 1995"
2,728 citations
26 Dec 1995
TL;DR: In this article, the authors present an algebraic version of elementary mathematics proofs without words, including the concept of special numbers and the notion of numbers without words in elementary algebra.
Abstract: Numbers and Elementary Mathematics Proofs without words Constants Special numbers Number theory Series and products Algebra Elementary algebra Polynomials Vector algebra Linear and matrix algebra Abstract algebra Discrete Mathematics Set theory Combinatorics Graphs Combinatorial design theory Difference equations Geometry Euclidean geometry Coordinate systems in the plane Plane symmetries or isometries Other transformations of the plane Lines Polygons Surfaces of revolution: the torus Quadrics Spherical geometry and trigonometry Conics Special plane curves Coordinate systems in space Space symmetries or isometries Other transformations of space Direction angles and direction cosines Planes Lines in space Polyhedra Cylinders Cones Differential geometry Analysis Differential calculus Differential forms Integration Table of indefinite integrals Table of definite integrals Ordinary differential equations Partial differential equations Integral equations Tensor analysis Orthogonal coordinate systems Interval analysis Real analysis Generalized functions Complex analysis Special Functions Ceiling and floor functions Exponentiation Logarithmic functions Exponential function Trigonometric functions Circular functions and planar triangles Tables of trigonometric functions Angle conversion Inverse circular functions Hyperbolic functions Inverse hyperbolic functions Gudermannian function Orthogonal polynomials Gamma function Beta function Error functions Fresnel integrals Sine, cosine, and exponential integrals Polylogarithms Hypergeometric functions Legendre functions Bessel functions Elliptic integrals Jacobian elliptic functions Clebsch-Gordan coefficients Integral transforms: Preliminaries Fourier integral transform Discrete Fourier transform (DFT) Fast Fourier transform (FFT) Multidimensional Fourier transforms Laplace transform Hankel transform Hartley transform Mellin transform Hilbert transform Z-Transform Tables of transforms Probability and Statistics Probability theory Classical probability problems Probability distributions Queuing theory Markov chains Random number generation Control charts and reliability Statistics Confidence intervals Tests of hypotheses Linear regression Analysis of variance (ANOVA) Sample size Contingency tables Probability tables Scientific Computing Basic numerical analysis Numerical linear algebra Numerical integration and differentiation Mathematical Formulae from the Sciences Acoustics Astrophysics Atmospheric physics Atomic physics Basic mechanics Beam dynamics Classical mechanics Coordinate systems - Astronomical Coordinate systems - Terrestrial Earthquake engineering Electromagnetic transmission Electrostatics and magnetism Electronic circuits Epidemiology Finance Fluid mechanics Fuzzy logic Human body Image processing matrices Macroeconomics Modeling physical systems Optics Population genetics Quantum mechanics Quaternions Relativistic mechanics Solid mechanics Statistical mechanics Thermodynamics Miscellaneous Calendar computations Cellular automata Communication theory Control theory Computer languages Cryptography Discrete dynamical systems and chaos Electronic resources Elliptic curves Financial formulae Game theory Knot theory Lattices Moments of inertia Music Operations research Recreational mathematics Risk analysis and decision rules Signal processing Symbolic logic Units Voting power Greek alphabet Braille code Morse code List of References List of Figures List of Notation Index
656 citations
TL;DR: In this paper, the development of thermal-hydraulic design tools for rectangular offset strip fin compact heat exchangers and the associated convection process are delineated, and existing empirical f and j data for actual cores are reanalyzed.
480 citations
TL;DR: In this article, the authors found that although Sony was as fast as any of its chief competitors in getting new models to market, an important explanation for the wide variety of models offered by the firm is the greater longevity of its key models.
477 citations
TL;DR: Concepts are described which provide design engineers with the insight to control performance and the understanding needed to ensure the secure operation of the bulk transmission system.
Abstract: The design of controllers sited in the transmission network for damping interarea power oscillations requires several types of analytical tools and field verification methods. Probably the most important aspect of such control design is the selection of proper feedback measurements from the network. This paper describes concepts which provide design engineers with the insight to control performance and the understanding needed to ensure the secure operation of the bulk transmission system. Specific attention is directed to procedures for selecting feedback signals. >
385 citations
20 Aug 1995
TL;DR: This work gives lock-free data structures and algorithms for implementing a shared singly-linked list, allowing concurrent traversal, insertion, and deletion by any number of processes, and shows how the basic data structure can be used as a building block for other lock- free data structures.
Abstract: Lock-free data structures implement concurrent objects without the use of mutual exclusion. This approach can avoid performance problems due to unpredictable delays while processes are within critical sections. Although universal methods are known that give lock-free data structures for any abstract data type, the overhead of these methods makes them inefficient when compared to conventional techniques using mutual exclusion, such as spin locks. We give lock-free data structures and algorithms for implementing a shared singly-linked list, allowing concurrent traversal, insertion, and deletion by any number of processes. We also show how the basic data structure can be used as a building block for other lock-free data structures. Our algorithms use the single word Compare-and-Swap synchronization primitive to implement the linked list directly, avoiding the overhead of universal methods, and are thus a practical alternative to using spin locks.
358 citations
TL;DR: In this paper, it is shown that sector zoning can arise as a natural consequence of slow lattice diffusion in refractory accessory minerals such as zircon and titanite.
Abstract: Abstract The occurrence of sector zoning in minerals of regional metamorphic or low-temperature intrusive origin implies that rapid growth is not required for the development of this particular form of homogeneous disequilibrium. It is shown here that sector zoning can be a natural consequence simply of slow lattice diffusion. Given anisotropic surface enrichment coupled with the low dilfusivities typical of highly charged elements in refractory accessory minerals such as zircon and titanite, sector zoning can arise even in cases of growth rjates as low as a few micrometers per million years. According to the proposed model, the development of sector zoning depends upon the competition between growth rate (V) and lattice diffusion (Di) within the near-surface layer (l), such that above a critical value of Vl/Di (~0.5-3), sector zoning is unavoidable in crystals that exhibit selective enrichment on some growth surfaces. Known diffusivities of rare earth elements in zircon and titanite lead to the expectation of sector zoning in these minerals with respect to REEs for reasonable geologic growth rates. Even in the case of clinopyroxene, diffusion of REEs and high field-strength elements may be slow enough to contribute to the development of sector zoning in laboratory-grown crystals.
296 citations
TL;DR: Transepithelial impedance of Madin-Darby canine kidney cell layers is measured by a new instrumental method, referred to as electric cell-substrate impedance sensing, and shows that reduction of Ca2+ concentration causes junction resistance between cells to drop and the distance between the basal cell surface and substratum to increase.
284 citations
TL;DR: A nonlinear control law which uses the feedback of the unit quaternion and the measured angular velocities is proposed and is shown to provide global asymptotic stability.
Abstract: This paper considers the problem of three-axis attitude stabilization of a rigid spacecraft. A nonlinear control law which uses the feedback of the unit quaternion and the measured angular velocities is proposed and is shown to provide global asymptotic stability. The control law does not require the knowledge of the system parameters and is, therefore, robust to modeling errors. The significance of the control law is that it can be used for large-angle maneuvers with guaranteed stability. >
276 citations
TL;DR: The technique of applying statistical methods to tolerance analysis of mechanical assemblies and the application of these methods to solid modelling systems and to the geometric tolerancing standard are described.
Abstract: The review paper describes the technique of applying statistical methods to tolerance analysis of mechanical assemblies. It states the problem, and reviews the various approaches proposed for statistical tolerance analysis. It also considers the important case of a nonideal probability distribution of component tolerances. Lastly, it reviews and assesses the application of these methods to solid modelling systems and to the geometric tolerancing standard, and makes recommendations about possible directions to be taken in future research on the subject.
260 citations
TL;DR: In this paper, a comparison of electromigration behavior of various possible interconnection metal in standard “bulk” state is made, followed by a review of the calculations made comparing the RC (resistance × capacitance) time constants of various material systems and the joule heating of the interconnection materials.
Abstract: The investigation of copper for use as an interconnection metal in the ultra large-scale integration (ULSI) era of silicon integrated circuits has accelerated in the past several years. The obvious advantages for using copper to replace currently used Al are related to its lower resistivity (1.7 μΩ-cm vs. 2.7 μω-cm for Al) and its higher electromigration resistance (several orders of magnitude higher compared with Al). The goal of this review is to examine the properties of copper and its applicability as the interconnection metal. A comparison of electromigration behavior of various possible interconnection metal in standard “bulk” state is made. This is followed by a review of the calculations made comparing (a) the RC (resistance × capacitance) time constants of various material systems and (b) the joule heating of the interconnection materials. A comparative study of various metal systems for the application as the interconnect metal is then made. These discussions will clearly establish the ...
TL;DR: In this paper, the authors describe the use of a stochastic search procedure that is the basis of genetic algorithms, in developing near-optimal topologies of load-bearing truss structures.
TL;DR: In this article, the authors used infrared spectroscopy to determine the fictive temperature of silica glasses and found that the equilibrium structural band positions were independent of impurity content, such as hydroxyl, in different types of glass.
Abstract: Infrared spectroscopy was used to determine fictive temperature of silica glasses. Positions of both the fundamental structural band at ∼ 1122 cm−1 monitored in infrared (IR) reflection mode and an overtone of this band at ∼ 2260 cm−1 monitored in IR transmission mode were found to be directly correlated with the glass fictive temperature. At any particular fictive temperature, the equilibrium structural band positions were found to be independent of the impurity content, such as hydroxyl, in different types of silica glass. From band shifts, the average SiOSi bond angle was computed to decrease by about 1.3° when the fictive temperature increased from 950 to 1400°C. Using this method, fictive temperatures of various as-received silica glasses were determined.
TL;DR: Analytically, it is demonstrated that MINPRAN distinguished good fits to random data andMINPRAN finds accurate fits and nearly the correct number of inliers, regardless of the percentage of true inLiers.
Abstract: MINPRAN is a new robust estimator capable of finding good fits in data sets containing more than 50% outliers. Unlike other techniques that handle large outlier percentages, MINPRAN does not rely on a known error bound for the good data. Instead, it assumes the bad data are randomly distributed within the dynamic range of the sensor. Based on this, MINPRAN uses random sampling to search for the fit and the inliers to the fit that are least likely to have occurred randomly. It runs in time O(N/sup 2/+SN log N), where S is the number of random samples and N is the number of data points. We demonstrate analytically that MINPRAN distinguished good fits to random data and MINPRAN finds accurate fits and nearly the correct number of inliers, regardless of the percentage of true inliers. We confirm MINPRAN's properties experimentally on synthetic data and show it compares favorably to least median of squares. Finally, we apply MINPRAN to fitting planar surface patches and eliminating outliers in range data taken from complicated scenes. >
TL;DR: The reported occurrence of drug-resistant schistosomes after treatment with oxamniquine and praziquantel suggests strict monitoring of such phenomena and encourages renewed efforts toward the development of multiple drugs against this human parasite.
TL;DR: New aggregation algorithms for obtaining reduced order power networks when coherent generators are aggregated will decrease the stiffening effect and produce, for the same coherent machine groups, aggregate networks with improved inter-area mode approximations.
Abstract: This paper presents new aggregation algorithms for obtaining reduced order power networks when coherent generators are aggregated. The generation terminal bus aggregation algorithm in the EPRI DYNRED software tends to stiffen the reduced order network during the aggregation process, thus increasing the frequencies of inter-area modes. The inertial and slow coherency aggregations will decrease the stiffening effect and produce, for the same coherent machine groups, aggregate networks with improved inter-area mode approximations. This paper contains new procedures to construct these aggregate networks and demonstrates the benefits of these new aggregate networks on a 48-machine power system using eigenvalues and nonlinear simulations. >
TL;DR: A detailed literature survey of multiple and bicriteria problems in scheduling can be found in this article, where the authors provide a broad classification scheme for scheduling problems and discuss the trade-offs involved in considering several different criteria.
TL;DR: The results suggest that although endogenous kappa opioid systems may not tonically modulate mechanisms involved in drug reinforcement, pharmacological activation of kappa pathways may be a novel and effective pharmacological approach to treating both opioid and stimulant addiction.
21 May 1995
TL;DR: This note shows that the angular velocity feedback can be replaced by a nonlinear filter of the quarternion, thus removing the need of direct angular velocity measurement, and exploits the inherent passivity of the system.
Abstract: It is well known that the linear feedback of the quarternion of the attitude error and angular velocity globally stabilizes the attitude of a rigid body. In this note, we show that the angular velocity feedback can be replaced by a nonlinear filter of the quarternion, thus removing the need of direct angular velocity measurement. In contrast to other approaches, this design exploits the inherent passivity of the system; a dynamic observer reconstructing the velocity is not needed. An application of the proposed scheme is illustrated for the robot control problem. Simulation results are included to illustrate the theoretical results.
TL;DR: The use of cathodoluminescence (CL) and/or backscattered electron (BSE) imaging techniques with in situ ion probe analyses of zircons can help unravel complex crustal histories of metamorphic rocks that otherwise might remain elusive as discussed by the authors.
TL;DR: In this paper, an active power filter for single-phase power systems which are comprised of multiple nonlinear loads is presented. But the spectral performance of the active filter is not evaluated.
Abstract: This paper presents active power filters for single-phase power systems which are comprised of multiple nonlinear loads. The paper provides background on the operation of the filter, the details of the power circuit, the details of the control design, representative waveforms, and spectral performance for a filter which supports a 384 W AC controller and a 900 W uncontrolled bridge rectifier. Experimental data indicate that the active filter typically consumes 3% or less of the average load power, suggesting that a parallel filter is an efficient compensation approach. The spectral performance shows that the active filter brings the system into compliance with IEC-555 for decision frequencies in excess of 30 kHz. A discussion is presented outlining an alternative single-phase active filter which uses two controllable switches and is based on a half-bridge topology. >
TL;DR: In this paper, infrared spectroscopy was used to measure structural changes, water surface concentrations and effective hydroxyl diffusion coefficients in silica glass during isothermal hydration heat-treatments at temperatures from 80 to 1150°C in 0.467 atm of water vapor.
Abstract: Infrared spectroscopy was used to measure structural changes, water surface concentrations and effective hydroxyl diffusion coefficients in silica glass during isothermal hydration heat-treatments at temperatures from 80 to 1150°C in 0.467 atm of water vapor. The observed glass structural changes were determined to be identical to relaxation during annealing, and it was found that infrared spectrometry may be used to measure glass fictive temperatures. Minute amounts of water had a pronounced accelerating effect on structural relaxation, and relaxation, in turn, affected the water content of the glass in three ways: (1) slow relaxation at low temperatures hindered the glass-water reaction or caused a slow increase of the reaction equilibrium constant; (2) expansion of the glass during water entry allowed an increase of the molecular water solubility; and (3) healing of the glass during bulk relaxation caused a decrease of the hydroxyl solubility. These processes occurred at different rates causing a peculiar increase and then decrease with time of both the surface hydroxyl concentration in thick specimens and total hydroxyl uptake in thin specimens. This observation was used to demonstrate that hydroxyl solubility measurements taken below 850°C by other researchers are not true equilibrium solubilities. Additionally, the kink at 550°C in the Arrhenius plot of Deff,OH as observed by Wakabayashi and Tomozawa in 1989 was found to be a time-dependent phenomenon which is explained in terms of slow glass-water reaction during relaxation. Diffusion of water into silica glass is therefore suggested to be bounded by two extremes: a high-temperature (> 850°C)/long-time extreme where relaxation and reaction are faster than diffusion and water diffuses according to the Doremus model and a low-temperature/short-time extreme in which relaxation and reaction are slower than diffusion and water penetration is limited only by the diffusion coefficient of molecular water in the glass.
TL;DR: In this article, a novel and general method for modifying hydrophobic poly (arylsulfone) ultrafiltration membranes to produce highly hydrophilic surfaces has been developed.
TL;DR: There is a high diversity of heterotrophic nitrogen-fixing organisms in marine cyanobacterial mats, with a few being most closely related to the cluster of (gamma)-proteobacteria containing Klebsiella and Azotob bacteria.
Abstract: The diversity of nitrogenase genes in a marine cyanobacterial mat was investigated through amplification of a fragment of nifH, which encodes the Fe protein of the nitrogenase complex. The amplified nifH products were characterized by DNA sequencing and were compared with the sequences of nitrogenase genes from cultivated organisms. Phylogenetic analysis showed that similar organisms clustered together, with the exception that anaerobic bacteria clustered together, even though they represented firmicutes, (delta)-proteobacteria, and (gamma)-proteobacteria. Mat nifH sequences were most closely related to those of the anaerobes, with a few being most closely related to the cluster of (gamma)-proteobacteria containing Klebsiella and Azotobacter species. No cyanobacterial nifH sequences were found from the mat collected in November when Microcoleus chthonoplastes was the dominant cyanobacterium, but sequences closely related to the cyanobacterium Lyngbya lagerheimeii were found during summer, when a Lyngbya strain was dominant. The results indicate that there is a high diversity of heterotrophic nitrogen-fixing organisms in marine cyanobacterial mats.
TL;DR: In this article, the usefulness of silicides and their thin films in microelectronics is discussed with emphasis on electrically conducting transition-metal silicides followed by a brief description of the device structure, contact resistance and interconnection delay.
01 May 1995
TL;DR: UnWindows VI is presented, a set of tools designed to assist low vision users of X Windows in effectively accomplishing two mundane yet critical interaction tasks: selectively magnifying areas of the screen so that the contents can be seen comfortably, and keeping track of the location of the mouse pointer.
Abstract: We present UnWindows VI, a set of tools designed to assist low vision users of X Windows in effectively accomplishing two mundane yet critical interaction tasks: selectively magnifying areas of the screen so that the contents can be seen comfortably, and keeping track of the location of the mouse pointer. We describe our software from both the end user's and implementor's points of view, with particular emphasis on issues related to screen magnification techniques. We conclude with details regarding software availability and plans for future extensions.
TL;DR: In this paper, the authors investigated the mechanisms by which removal and planarization occur during the chemical mechanical polishing of copper, used for pattern delineation in a multilevel metallization scheme, and proposed that removal occurs as mechanical abrasion of the surface followed by chemical dissolution of the abraded species.
TL;DR: This paper presents planning algorithms for finding a set of sensing operations for completely measuring the exposed surface of an object to be inspected and these algorithms are applicable to other inspection systems and other applications than inspection.
TL;DR: In this article, the authors investigated the interconnectivity of carbonate melts in a synthetic dunite at low melt fractions at 1 GPa and 1300° C and found that carbonate melt remains interconnected to 0.05 wt% in fine-grained olivine (all grains initially ≤ 63 μm).
TL;DR: The diffusion of water into silica glass is modeled to result from the diffusion of molecular water into the glass and its reaction with the silicon-oxygen network to form SiOH groups as discussed by the authors.
Abstract: The diffusion of water into silica glass is modeled to result from the diffusion of molecular water into the glass and its reaction with the silicon-oxygen network to form SiOH groups. Equations for this diffusion-reaction mechanism are presented and compared with experimental diffusion profiles. At temperatures above about 500 °C the reaction goes to equilibrium, but at lower temperatures it does not, leading to a time dependence of the concentration of surface-reacted OH groups and of their apparent diffusion coefficient. At higher temperatures, the OH groups are nearly immobile, but diffuse far enough to sample neighboring OH groups, leading to a bimolecular reverse reaction. At lower temperatures only OH pairs react, giving a first-order reaction. When water tagged with O18 diffuses into silica, the O18 exchanges with O16 in the silicon-oxygen network of the glass. This process is also controlled by the rate of diffusion of molecular water into the glass, and the rate of O18-O16 exchange. This diffusion-reaction mechanism gives a unified description of the diffusion of water in silica glass from 160 °C to 1200 °C at least.