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The Missouri Miner, August 31, 1994 Aug 1994

The Missouri Miner, August 31, 1994

The Missouri Miner Newspaper

No abstract provided.

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Orientation Induced Scattering Asymmetry, Jee-Ching Wang, Ronald E. Olson Aug 1994

Orientation Induced Scattering Asymmetry, Jee-Ching Wang, Ronald E. Olson

Chemical and Biochemical Engineering Faculty Research & Creative Works

Projectile angular scattering is investigated following electron capture by protons from circular Rydberg atoms oriented along a quantization axis perpendicular to the incident projectile direction. We find strong left-right scattering asymmetry as a function of the orientation angle at collision speeds comparable to the electron orbital speed. The capture cross section is dramatically enhanced due to velocity matching when the angular momenta of the proton and the electron are aligned. The scattering asymmetry exhibits characteristic impact parameter dependencies suitable for studying three-body dynamics influenced by both long and short range forces of comparable strength. © 1994 IOP Publishing Ltd.

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He²⁺-He Collisions: One-Electron Capture And Target-Ion Excitation, H. O. Folkerts, F. W. Bliek, L. Meng, Ronald E. Olson, R. Morgenstern, M. V. Von Hellermann, H. P. Summers, R. Hoekstra Aug 1994

He²⁺-He Collisions: One-Electron Capture And Target-Ion Excitation, H. O. Folkerts, F. W. Bliek, L. Meng, Ronald E. Olson, R. Morgenstern, M. V. Von Hellermann, H. P. Summers, R. Hoekstra

Physics Faculty Research & Creative Works

By means of photon emission spectroscopy the authors have studied state selective one-electron capture and target-ion excitation in collisions of He2+ with He. The collision energy has been varied from 1 to 75 keV amu-1. Four-body classical trajectory Monte Carlo calculations have been performed in the energy range of 50-300 keV amu-1. In the energy range where experiment and theory overlap there is in general fair agreement, although the l-distributions within a principal quantum shell exhibit differences. At energies below 50 keV amu-1 the experiments confirm the results of atomic orbital calculations, presented in an accompanying paper by Fritsch (1994). …

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Ccfss Technical Bulletin August 1994, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 1994

Ccfss Technical Bulletin August 1994, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

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Asymmetric Upwarp Of The Asthenosphere Beneath The Baikal Rift Zone, Siberia, Stephen S. Gao, Paul M. Davis, Kelly H. Liu, Philip D. Slack, Yu A. Zorin, Nikolai A. Logatchev, M. Kogan, P. D. Burkholder, Robert P. Meyer Aug 1994

Asymmetric Upwarp Of The Asthenosphere Beneath The Baikal Rift Zone, Siberia, Stephen S. Gao, Paul M. Davis, Kelly H. Liu, Philip D. Slack, Yu A. Zorin, Nikolai A. Logatchev, M. Kogan, P. D. Burkholder, Robert P. Meyer

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

In the summer of 1991 we installed 27 seismic stations about lake Baikal, Siberia, aimed at obtaining accurately timed digital seismic data to investigate the deep structure and geodynamics of the Baikal rift zone and adjacent regions. Sixty-six teleseismic events with high signal-to-noise ratio were recorded. Travel time and Q analysis of teleseisms characterize an upwarp of the lithosphere-asthenosphere boundary under Baikal. Theoretical arrival times were calculated by using the International Association of Seismology and Physics of the Earth's interior 1991 Earth model, and travel time residuals were found by subtracting computed arrival times from observed ones. A three-dimensional downward …

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How To Program In Ccsp, Beth Arrowsmith Aug 1994

How To Program In Ccsp, Beth Arrowsmith

Computer Science Technical Reports

No abstract provided.

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Neutron-Diffraction Study Of Γ-Fe At High Pressure, Oran Allan Pringle, Rafael Calvo, R. E. Parra Aug 1994

Neutron-Diffraction Study Of Γ-Fe At High Pressure, Oran Allan Pringle, Rafael Calvo, R. E. Parra

Physics Faculty Research & Creative Works

Face-centered-cubic iron (γ-Fe) coherently precipitated in a single crystal of Cu has been studied by neutron diffraction at high pressures up to 0.9 GPa and in the temperature range from about 5 to 110 K. It undergoes antiferromagnetic ordering at 67±2 K at ambient pressure. The ordering temperature TN monotonically decreases with increasing pressure following a relation TN(K)=67-12.8p - 11.1p2 - 6.17p3, where p is in units of GPa. The change of TN in γ-Fe is discussed in terms of the volume change caused by pressurization or by alloying.

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Landau-Zener Treatment Of Intensity-Tuned Multiphoton Resonances Of Potassium, J. Greg Story, D. I. Duncan, Thomas F. Gallagher Aug 1994

Landau-Zener Treatment Of Intensity-Tuned Multiphoton Resonances Of Potassium, J. Greg Story, D. I. Duncan, Thomas F. Gallagher

Physics Faculty Research & Creative Works

When exposed to intense light of ~580 nm, the ground state of K shifts up in energy, passing through two photon resonances with Rydberg states, and finally crossing the two-photon ionization limit. We have used laser pulses of varying duration to study the nature of the population transfer from the ground state to the excited state due to the intensity-tuned resonances encountered during the rising edge of the pulse. A dynamic Floquet approach in which the resonances are treated as avoided crossings of the Floquet energy levels is used to model the population transfer and gives excellent agreement with the …

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Effect Of Carrier Gas Pressure On Condensation In A Supersonic Nozzle, Barbara Ellen Wyslouzil, Gerald Wilemski, M. G. Beals, Michael B. Frish Aug 1994

Effect Of Carrier Gas Pressure On Condensation In A Supersonic Nozzle, Barbara Ellen Wyslouzil, Gerald Wilemski, M. G. Beals, Michael B. Frish

Physics Faculty Research & Creative Works

Supersonic nozzle experiments were performed with a fixed water or ethanol vapor pressure and varying amounts of nitrogen to test the hypothesis that carrier gas pressure affects the onset of condensation. Such an effect might occur if nonisothermal nucleation were important under conditions of excess carrier gas in the atmospheric pressure range, as has been suggested by Ford and Clement [J. Phys. A 22, 4007 (1989)]. Although a small increase was observed in the condensation onset temperature as the stagnation pressure was reduced from 3 to 0.5 atm, these changes cannot be attributed to any nonisothermal effects. The pulsed nozzle …

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Ccfss News August 1994, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 1994

Ccfss News August 1994, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

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Identifying And Quantifying Printed Circuit Board Inductance, Todd H. Hubing, Thomas Van Doren, James L. Drewniak Aug 1994

Identifying And Quantifying Printed Circuit Board Inductance, Todd H. Hubing, Thomas Van Doren, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The concepts of inductance and partial inductance play a key role in printed circuit board (PCB) modeling. The inductance of the signal path is an important parameter in high-speed signal integrity calculations. Delta_I noise modeling, crosstalk calculations, and common-mode source identification all rely heavily on accurate estimations of the partial inductance associated with traces, vias, and signal return paths on printed circuit boards. The paper begins by identifying and quantifying the parameters that affect the inductance of typical PCB geometries. Closed-form equations are provided for estimating the partial inductances of simple trace, via, and ground plane configurations. Finally, the issue …

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Modeling Power Bus Decoupling On Multilayer Printed Circuit Boards, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, P. Baudendistal Aug 1994

Modeling Power Bus Decoupling On Multilayer Printed Circuit Boards, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, P. Baudendistal

Electrical and Computer Engineering Faculty Research & Creative Works

Power bus decoupling designs on multilayer printed circuit boards must adequately account for the power bus interplane capacitance and its consequences for the design. Lumped element models for a power bus on a multilayer printed circuit board where an appreciable or entire portion of a layer is devoted to power and ground have been developed. The models are applicable below the distributed resonances of the board. Analytical, circuit simulation, and experimental studies have been conducted to test the models, investigate the effects of the distributed interplane capacitance of the power bus, and the effect of interconnect inductance associated with surface-mount …

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The Multirate Method For Simulation Of Power System Dynamics, J. G. Chen, Mariesa Crow Aug 1994

The Multirate Method For Simulation Of Power System Dynamics, J. G. Chen, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the multirate method is introduced to analyse power system behavior for systems with widely varying time constants. Estimates for computational speed-up are derived based on a linear system approach. The method is applied to a small power system example and the results, both in terms of accuracy and computation time, are compared to traditional simulation methods

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Investigation Of Fundamental Mechanisms Of Common-Mode Radiation From Printed Circuit Boards With Attached Cables, James L. Drewniak, Todd H. Hubing, Thomas Van Doren Aug 1994

Investigation Of Fundamental Mechanisms Of Common-Mode Radiation From Printed Circuit Boards With Attached Cables, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Fundamental mechanisms leading to common-mode radiation from printed circuit boards with attached cables have been studied. Two primary mechanisms have been identified, one associated with a differential-mode voltage that results in a common-mode current on an attached cable, and another associated with a differential-mode current that results in a common-mode current on the cable. The two mechanisms are demonstrated through numerical and experimental results.

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Common Mode Currents Induced On Wires Attached To Multilayer Printed Wire Boards With Segmented Ground Planes, R. Lee Hill, Thomas Van Doren, Todd H. Hubing, James L. Drewniak, Franz Gisn Aug 1994

Common Mode Currents Induced On Wires Attached To Multilayer Printed Wire Boards With Segmented Ground Planes, R. Lee Hill, Thomas Van Doren, Todd H. Hubing, James L. Drewniak, Franz Gisn

Electrical and Computer Engineering Faculty Research & Creative Works

An investigation has been undertaken to further study the fundamental mechanisms responsible for inducing high frequency common mode currents on wires attached to multilayer printed wire boards (PWBs). Previous work reported in the EMC literature has demonstrated that the presence of unintended common mode currents on the external cables of electronic equipment is often the primary source of radiated EMI at frequencies above 30 MHz. In an attempt to reduce the magnitude of these currents to yield `quieter' electronic products, many EMC engineers have implemented segmented or `gapped' ground plane geometries in mulilayer PWB designs. The objective of this study …

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Teaching The Practice Of Formal Methods In Distributed Computing Systems - A Module, Beth Arrowsmith, Bruce Mcmillin Jul 1994

Teaching The Practice Of Formal Methods In Distributed Computing Systems - A Module, Beth Arrowsmith, Bruce Mcmillin

Computer Science Technical Reports

No abstract provided.

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Missouri S&T Magazine, Autumn 1994, Miner Alumni Association Jul 1994

Missouri S&T Magazine, Autumn 1994, Miner Alumni Association

Missouri S&T Magazine

No abstract provided.

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A Novel Microwave Fatigue Crack Detection Technique Using An Open-Ended Coaxial Line, Nasser N. Qaddoumi, Stoyan I. Ganchev, R. Zoughi Jul 1994

A Novel Microwave Fatigue Crack Detection Technique Using An Open-Ended Coaxial Line, Nasser N. Qaddoumi, Stoyan I. Ganchev, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Surface crack detection on metallic structures (aircraft fuselage, turbine blades and nuclear power plant steam generator turbines) is of utmost importance. The use of an open-ended coaxial line for this purpose is very attractive because it offers advantages such as a wide frequency band of operation, small aperture (sensing) area, and excellent sensitivity.

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Differential Transfer Ionization Cross Sections For 50175-Kev Proton-Helium Collisions, S. W. Bross, S. M. Bonham, A. D. Gaus, Jerry Peacher, Tibor Vajnai, Michael Schulz, Horst Schmidt-Bocking Jul 1994

Differential Transfer Ionization Cross Sections For 50175-Kev Proton-Helium Collisions, S. W. Bross, S. M. Bonham, A. D. Gaus, Jerry Peacher, Tibor Vajnai, Michael Schulz, Horst Schmidt-Bocking

Physics Faculty Research & Creative Works

We have measured coincidences between neutralized projectiles and He recoil ions for 50175-keV proton-helium collisions. From the data we obtained transfer ionization (TI) cross sections differential in the projectile scattering angle. Laboratory scattering angles range from 0 to 2.0 mrad. The experimental method allowed separation of the postcollision charge states of the target atoms. The ratio of the cross sections for TI to the sum of TI and single capture, F, is presented as a function of projectile scattering angle. Comparison is made to previous measurements of this ratio where data is available. The differential cross sections are compared to …

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Critical Correlations And Susceptibilities In The Random-Field Spherical Model, Thomas Vojta, Michael Schreiber Jul 1994

Critical Correlations And Susceptibilities In The Random-Field Spherical Model, Thomas Vojta, Michael Schreiber

Physics Faculty Research & Creative Works

We investigate the behavior of the correlation function and the susceptibility of the random-field spherical model at the critical point. In particular we calculate the critical exponents η and η- describing the divergences of the susceptibility and its disconnected part, respectively. In the case of short-range interactions we obtain η=η-=0. For power-law interactions Uij~rij-σ we find η=1/2η-=D+2-σ (for D<σ

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Simple Apparatus For Producing Single Liquid Drops, Dhiren Panda, D. G. C. Robertson Jul 1994

Simple Apparatus For Producing Single Liquid Drops, Dhiren Panda, D. G. C. Robertson

Materials Science and Engineering Faculty Research & Creative Works

A simple experimental apparatus has been used to produce individual mercury and sodium amalgam drops in the size range of 0.3-2.5 mm diam. A high resistance to the flow of liquid was provided by a capillary tube. The cross section consisted of a 0.20 mm o.d. tungsten wire placed in a 0.25 mm capillary bore. By this method, flow rates of 1 μl/s and lower were obtained, which enabled the formation of drops as small as 1 mm diam in a time interval of 20 s. The drops were formed at a plastic tip, and on reaching the desired size, …

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A Magnetic, Neutron Diffraction, And Mössbauer Spectral Study Of Nd₂Fe₁₅Ga₂ And The Tb₂Fe₁₇₋ₓgaₓ Solid Solutions, Zhong Bo Hu, William B. Yelon, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, D. P. Middleton, K. H. J. Buschow, Fernande Grandjean Jul 1994

A Magnetic, Neutron Diffraction, And Mössbauer Spectral Study Of Nd₂Fe₁₅Ga₂ And The Tb₂Fe₁₇₋ₓgaₓ Solid Solutions, Zhong Bo Hu, William B. Yelon, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, D. P. Middleton, K. H. J. Buschow, Fernande Grandjean

Physics Faculty Research & Creative Works

An x-ray diffraction study of the substitution of gallium in Tb 2Fe17 to form the Tb2Fe17-xGax solid solutions indicates that the compounds adopt the rhombohedral Th2Zn17 structure. The unit cell volume and the a-axis lattice parameter increase linearly with increasing gallium content. The c-axis lattice parameter increases linearly from x=0 to 6 and then decreases between x=7 and 8. Magnetic studies show the Curie temperature increases by ~150° above that of Tb2Fe17 to reach a maximum between x=3 and 4, and then decreases with further increases in …

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Simulation Of Communication Systems, William H. Tranter, Kurt Louis Kosbar Jul 1994

Simulation Of Communication Systems, William H. Tranter, Kurt Louis Kosbar

Electrical and Computer Engineering Faculty Research & Creative Works

When both a complex system and a complex channel model are encountered, the result is typically a design or analysis problem that cannot be solved using traditional (pencil and paper) mathematical analysis. Computer-aided techniques, which usually involve some level of numerical simulation, can be a very valuable tool in these situations. The purpose of this article is to provide a tutorial review of some of the basic techniques of communication system simulation. The authors consider the basic techniques used to represent signals, generate signals, and model linear systems, nonlinear systems, and time-varying systems within a simulation. They consider the important …

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Analysis Of Radiation From An Open-Ended Coaxial Line Into Stratified Dielectrics, Sasan Bakhtiari, Stoyan I. Ganchev, R. Zoughi Jul 1994

Analysis Of Radiation From An Open-Ended Coaxial Line Into Stratified Dielectrics, Sasan Bakhtiari, Stoyan I. Ganchev, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Radiation from an open-ended coaxial transmission line into an N-layer dielectric medium is studied in application to nondestructive evaluation of materials. Explicit formulations for two cases of layered media, one terminated into an infinite half-space and the other into a conducting sheet are addressed in general form. In the theoretical derivations it is assumed that only the fundamental TEM mode propagates inside the coaxial line. The terminating admittance of the line is then formulated using the continuity of the power flow across the aperture. The admittance expressions for specific cases of two-layer dielectric composite with generally lossy dielectric properties, and …

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Detection Optimization Of Disbond In Layered Composites With Varying Thicknesses Using An Open-Ended Rectangular Waveguide, Stoyan I. Ganchev, Nasser N. Qaddoumi, R. Zoughi Jul 1994

Detection Optimization Of Disbond In Layered Composites With Varying Thicknesses Using An Open-Ended Rectangular Waveguide, Stoyan I. Ganchev, Nasser N. Qaddoumi, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The detection of air disbond in layered dielectric composite, which is an important practical issue in many industries, is studied both theoretically and experimentally. Sensitivity of disbond detection depends on certain parameters, like the frequency of operation, the distance between the sensor and the first dielectric layer, and the layered composite geometry (conductor backed or terminated by an infinite half-space of air). The impact of all these parameters is investigated theoretically and then verified experimentally.

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Projectile And Electron Spectra Resulting From Positron-Argon Collisions, R. A. Sparrow, Ronald E. Olson Jun 1994

Projectile And Electron Spectra Resulting From Positron-Argon Collisions, R. A. Sparrow, Ronald E. Olson

Physics Faculty Research & Creative Works

A three-body classical trajectory Monte-Carlo calculation is used to evaluate the differential cross sections for the ejected electron, as well as the projectile scattering for 50, 100 and 150 eV e++Ar0 electron removal collisions. In the ionized eleciron spectra both the electron capture to the continuum (ecc) and binary peak structures are observed. The theoretical ecc peak is diffuse and shifted to lower energies than expected from simple arguments. The calculated double differential cross sections for electron ejection have been compared to experiment, When the experimental apparatus function of Moxom et al is used to convolute the theoretical spectra, good …

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The Response Of Dispersion-Strengthened Copper Alloys To High Fluence Neutron Irradiation At 415⁰C, Danny J. Edwards, Joseph William Newkirk, Frank A. Garner, Margaret L. Hamilton, A. Nadkarni, P. Samal Jun 1994

The Response Of Dispersion-Strengthened Copper Alloys To High Fluence Neutron Irradiation At 415⁰C, Danny J. Edwards, Joseph William Newkirk, Frank A. Garner, Margaret L. Hamilton, A. Nadkarni, P. Samal

Materials Science and Engineering Faculty Research & Creative Works

Various oxide-dispersion-strengthened copper alloys have been irradiated to 150 dpa at 415°C in the Fast Flux Test Facility (FFTF). The Al2O3-strengthened GlidCop™ alloys, followed closely by a HfO2-strengthened alloy, displayed the best swelling resistance, electrical conductivity, and tensile properties. The conductivity of the HfO2-strengthened alloy reached a plateau at the higher levels of irradiation, instead of exhibiting the steady decrease in conductivity observed in the other alloys. A high initial oxygen content resulted in significantly higher swelling for a series of castable oxide-dispersion-strengthened alloys, while a Cr2O3 -strengthened alloys …

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State-Selective Electron Capture In He²⁺-H2 Collisions, L. Meng, Ronald E. Olson, H. O. Folkerts, R. Hoekstra Jun 1994

State-Selective Electron Capture In He²⁺-H2 Collisions, L. Meng, Ronald E. Olson, H. O. Folkerts, R. Hoekstra

Physics Faculty Research & Creative Works

A classical phase-space model of the hydrogen molecule which includes both electrons and nuclear centers is utilized to study state selective electron capture for collisions with alpha particles at intermediate impact energies (30-200 keV amu‑1), The calculations are performed within the framework of the classical trajectory Monte Carlo method. The direct one-electron transfer process and the transfer ionization reaction which becomes increasingly important at the higher impact energies are directly included in the cross section determinations. Photon emission spectroscopy experiments were conducted to obtain line emission cross sections for capture to the He+(np) states, n = 2-5, for energies from …

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Qualitative Study Of The Symplectic Stormer-Verlet Integrator, D. J. Hardy, D. I. Okunbor Jun 1994

Qualitative Study Of The Symplectic Stormer-Verlet Integrator, D. J. Hardy, D. I. Okunbor

Computer Science Technical Reports

Symplectic numerical integrators, such as the Stormer-Verlet method, are useful in preserving certain important properties that are not preserved by conventional numerical integrators. This paper analyzes the Stormer-Verlet method as applied to the simple harmonic model, which is an important model for molecular dynamics simulations. Restricting our attention to the one-dimensional case, both the exact solution and the Stormer-Verlet solution to this model are expressed as functions of the number of time steps taken, and then both of these functions are interpreted geometrically. The paper shows the existence of an upper bound on the error from the Stormer-Verlet method, and …

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Hardware Assists For High Performance Computing Using A Mathematics Of Arrays, H. Pottinger, W. Eatherton, L. Mullin, T. Schiefelbein Jun 1994

Hardware Assists For High Performance Computing Using A Mathematics Of Arrays, H. Pottinger, W. Eatherton, L. Mullin, T. Schiefelbein

Computer Science Technical Reports

Work in progress at the University of Missouri - Rolla on hardware assists for high performance computing and communication is presented. This research consists of a field programmable gate array based rapid prototyping environment (Chameleon) being used to evaluate hardware architectures for speedup of array partitioning and routing algorithms. These algorithms have been developed using a Mathematics of Arrays (MOA) and are optimal in the sense that they reduce normal array indexing operations to a series of primitive additions based on array shape. The method is simple yet powerful, produces algorithms which are provably correct, and are independent of dimensionality. …

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