Digital Commons Network^™

Adaptive Execution Of Data Parallel Computations On Networks Of Heterogeneous Workstations, Robert Prouty, Steve Otto, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Parallel environments consisting of a network of heterogeneous workstations introduce an inherently dynamic environment that differs from multicomputers. Workstations are usually considered “shared” resources while multicomputers provide dedicated processing power. The number of workstations available for use is continually changing; the parallel machine presented by the network is in effect continually reconfiguring itself. Application programs must effectively adapt to the changing number of processing nodes while maintaining computational efficiency. This paper examines methods for adapting to this dynamic environment within the framework of explicit message passing under the data parallel programming model. We present four requirements which we feel a …

Culture And Consensus: The Use Of Mathematical Models To Examine A Culture Of Sports In The Portland Metropolitan Area, Phillip M. Crawford

Dissertations and Theses

The question of what constitutes a culture has often been answered in one phrase: shared knowledge. Recent developments in both the theory and mathematics of examining this shared cultural knowledge allow researchers to produce mathematical models of informants' knowledge and perceptions of the culture they belong to. Many studies in cognitive anthropology have utilized these theoretical and mathematical tools: the present research sought to integrate a research design (based on the theory and mathematics mentioned above) with a relatively new cultural domain: the culture of sports.

Three main question pertaining to cultural knowledge were addressed in this research:

1. Did an …

Solubility Studies Of Iron(Iii) Oxides And Hydroxides, Victor L. Menting

Dissertations and Theses

The hydrolysis of iron(III) ions in aqueous solution forms a series of soluble hydroxide complexes with associated equilibrium constants. The solubility of iron(III) is controlled by the various soluble hydroxide complexes, and can, in theory, be calculated from the pH and equilibrium constants. Experimental verification of the calculated solubility has proven difficult due to the lack of sensitive analytical techniques and the presence of colloidal ferric hydroxide interferences. Recently, electrochemical methods for the determination of low levels of iron(III) have been developed using adsorptive cathodic stripping voltammetry which relies on the interfacial accumulation of the chelate of iron with Solochrome …

Comet: A Synthetic Benchmark For Message-Passing Architectures, Nalini Ganapati, Steve Otto, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Rapid advances in hardware technology have led to wide diversity in parallel computer architectures. This diversity makes it difficult to evaluate or compare the performance of different parallel computers. Existing benchmarks tend either to be too architecture-specific, or too high-level. Both problems can result in benchmarks that not only provide insufficient information on the performance characteristics of the computer being tested, but are also difficult to port. New benchmarking approaches are needed for new architectural classes, particularly distributed-memory, message-passing computers. This paper focuses on benchmarking distributed-memory message-passing computers. A synthetic benchmark called CoMet (COmmunication METrics), is presented. CoMet is based …

The Schooling Of Vietnamese-American High School Students In Oregon: Their Perspectives, Minh Van Tran

Dissertations and Theses

Research on the education of Vietnamese-Americans is very limited, and mainstream media continue to project Vietnamese students either as high achievers or gang affiliated (Castro, 1983; Davis & McDaid, 1992). This kind of projection can mask the real issues that Vietnamese students are facing. Based on Cummins' (1979) Contextual Interaction Theory, this study examined the views of Vietnamese-American high school students in Oregon regarding their schooling under four major areas: Community Background Factors, Educational Input Factors, Instructional Treatment, and Student Input Factors. In particular, this study examined factors, within the above four areas, pertaining to the schooling of Vietnamese-American high …

Persistence Influences On The Minority Student Attending A Predominantly White Postsecondary Urban Institution: The Student Perspective, Annmarie O'Brien

Dissertations and Theses

This dissertation is an examination of influences that have contributed to the retention of a group of minority students attending a predominately white postsecondary institution. The focus of the study is on the students' perspectives and the meaning and personal interpretation students draw from influences that impinge upon them and from their interactions with the college experience. From a sociological perspective this view and emphasis on meaning is described as the sociology of everyday life. The component of the sociology of everyday life which directed the methodology is symbolic interactionism. The data collection instrument was a focused interview. Variables from …

Threshold Characteristics Of Multimode Semiconductor Lasers, Lee W. Casperson, Mehdi Khoshnevissan

Electrical and Computer Engineering Faculty Publications and Presentations

The effects of spontaneous emission on the threshold characteristics of multimode laser oscillators with mixed line broadening are considered in detail. Most previous studies of multimode laser operation have emphasized the two limits of homogeneous and inhomogeneous broadening. With homogeneous broadening there is a tendency for oscillation in a single longitudinal mode, while in the inhomogeneous limit oscillation over much of the gain spectrum is expected. All practical lasers are somewhere between these limits, and this study explores the mode characteristics of lasers with mixed line broadening. Special attention is given to the important practical case of semiconductor diode lasers, …

Neutron-Scattering Study Of Librations And Intramolecular Phonons In Rb_{2.6}K_{0.4}C_{60}, D. Reznik, W. A. Kamitakahara, D. A. Neumann, J. R. D. Copley, J. E. Fischer, Robert M. Strongin, M. A. Cichy, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

We report the results of inelastic neutron-scattering measurements on Rb_2.6K_0.4C₆₀. Librational modes were observed as broad peaks with maxima between 4.1 and 4.7 meV, as the temperature is lowered from 300 to 12 K. As in K₃C₆₀, no change in the width or position of the librational peak was observed when the sample was cooled through the superconducting transition. Thus any coupling of the librations to electronic states is small. The magnitude of the orientational potential barrier was estimated from the librational peak frequency. A flat background observed in the …

A Simultaneous Route-Level Transit Patronage Model: Demand, Supply, And Inter-Route Relationship, Zhongren Peng

Dissertations and Theses

It is observed that transit riders are responding to service changes while transit planning is responding to ridership changes, or that transit patronage and service supply are highly interrelated. It is also noticed that transit riders transfer from route to route, the introduction of new service may draw some riders from the existing routes, which implies transit patronage on a route is also affected by other parallel and intersecting routes. An analytic tool is needed to examine these complex relationships in the transit system. This study has developed a quantitative model by incorporating these interactions into a simultaneous system. The …

Numerical Simulation Of Nonequilibrium Effects In An Argon Plasma Jet, C. H. Chang, John D. Ramshaw

Physics Faculty Publications and Presentations

Departures from thermal (translational), ionization, and excitation equilibrium in an axisymmetric argon plasma jet have been studied by two?dimensional numerical simulations. Electrons, ions, and excited and ground states of neutral atoms are represented as separate chemical species in the mixture. Transitions between excited states, as well as ionization/recombination reactions due to both collisional and radiative processes, are treated as separate chemical reactions. Resonance radiation transport is represented using Holstein escape factors to simulate both the optically thin and optically thick limits. The optically thin calculation showed significant underpopulation of excited species in the upstream part of the jet core, whereas …

A Model For Comprehensive Reform In General Education: Portland State University, Charles R. White

University Studies Assessment Research

Article presenting General Education Working Group Recommendations, research and rational for implementing the University Studies program.

Source Rock Geochemistry Of The Southern Tyee Basin, Southwest Oregon, David E. Long

Dissertations and Theses

This study examined source rock geochemistry of the southern Tyee Basin. Total organic carbon, rock-eval pyrolysis, vitrinite reflectance, thermal alteration index and visual assessments were performed on splits from cutting samples from five wells and on outcrop samples from four measured sections. Organic matter was found to be dispersed, averaging about 0.5 weight percent. The organic matter is primarily terrestrial in origin, or type I l l , with low potential for gas production and no oil potential. Three coal samples are clearly the richest sources of organic matter examined in this study.

Programmable Analog Array Circuit, Marek Perkowski, Edmund Pierzchala

Electrical and Computer Engineering Faculty Publications and Presentations

There is disclosed a programmable analog or mixed analog/ digital circuit. More particularly, this invention provides a circuit architecture that is ?exible for a programmable electronic hardWare device or for an analog circuit Whose input and output signals are analog or multi-valued in nature, and primarily continuous in time. There is further disclosed a design for a current-mode integrator and sample-and-hold circuit, based upon Miller effect.

Carbon Monoxide In The Antarctic Atmosphere: Observations Of Decreasing Concentrations, M. A. K. Khalil, R. A. Rasmussen

Environmental Science and Management Faculty Publications and Presentations

Hydroxyl radicals remove hundreds, perhaps thousands, of organic gases from the atmosphere and are often regarded as am index of the oxidizing capacity of the Earth's atmosphere (Thompson 1992). In recent years, there have been growing concerns that, over the past century and now, human activities may be depleting hydroxyl concentrations by adding huge amounts of carbon monoxide and methane to the atmosphere. Reduction in the hydroxyl concentrations can then indirectly lead to more global warming, stratospheric ozone depletion, and other disturbances in atmospheric chemistry. Carbon monoxide (CO) is a key component in the determination of hydroxyl radical (OH) concentrations: …

A Method For Determining Ice-Thickness Change At Remote Locations Using Gps, Christina L. Hulbe, I. M. Whillans

Geology Faculty Publications and Presentations

Ice-thickness changes at remote locations on ice sheets can be determined by means of precise Global Positioning System (GPS) surveys with interferometric solutions. Remote sites are precisely surveyed relative to GPS receivers on rock. Repeat observations of the position of a remote site provide its vertical velocity. The difference between this velocity and accumulation rate is an indicator of change in ice-sheet thickness. Allowance must be made for the movement of survey markers due to firn compaction and down-slope ice motion, To allow for firn compaction, very long- poles arc placed to a sufficient depth in the firn that the …

Evaluation Of Strain Rates On Ice Stream B, Antarctica, Obtained Using Differential Gps, Christina L. Hulbe, I. M. Whillans

Geology Faculty Publications and Presentations

The "stop-and-go" kinematic Global Positioning System (CPS) technique was used to survey 270 stations twice within a 25 km by 10 km strain grid on the surface of Ice Stream B. One or two geodetic quality receivers operated as reference pivots, while two similar receivers traveled to grid stations. Each station was occupied for 25 s. The method is rapid and reliable. Each survey was completed within 2 weeks. Calculated horizontal strain rates are accurate to 1%. Relative vertical velocities are accurate to 20 mm kmI a-1. Maps of the four horizontal velocity gradients, relative vertical velocity and surface elevation …

Atmospheric Hydrocarbon Analysis, Dawei Han

Dissertations and Theses

This treatise studied two correlated important issues in atmospheric chemistry: real-time monitoring of ambient air and removal mechanisms of atmospheric hydrocarbons. An analytical system was designed for the purpose of identification and measurement of sub-ppb level hydrocarbons of different reactivities in air samples. This analytical system was then applied to a series of smog-chamber studies which simulated the removal of reactive hydrocarbons from the atmosphere by reaction with hydroxyl radicals. Six representative atmospheric hydrocarbons (hexane, octane, toluene, m-xylene, a-xylene and mesitylene) were selected for these experiments. The experimental data indicated that the decay of atmospheric hydrocarbons under laboratory conditions is …

Script-Based Qos Specifications For Multimedia Presentations, Richard Staehli, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Multimedia presentations can convey information not only by the sequence of events but by their timing. The correctness of such presentations thus depends on the timing of events as well as their sequence and content. This paper introduces a formal specification language for playback of real-time presentations. The main contribution of this language is a quality of service (QOS) specification that relaxes resolution and synchronization requirements for playback. Our definitions give a precise meaning to the correctness of a presentation. This specification language will form the basis for a QOS interface for reservation of operating system resources.

Pattern Recognition And Erp Waveform Analysis Using Wavelet Transform, Hong Qi

Dissertations and Theses

Wavelet transform provides an alternative to the classical Short-Time Fourier Transform (STFT). In contrast to the STFT, which uses a single analysis window, the Wavelet Transform uses shorter windows at higher frequencies and longer windows at lower frequencies. For some particular wavelet functions, the local maxima of the wavelet transform correspond to the sharp variation points of the signal. As an application, wavelet transform is introduced to the character recognition. Local maximum of wavelet transform is used as a local feature to describe character boundary. The wavelet method performs well in the presence of noise. The maximum of wavelet transform …

Modeling Of The Surface Plasmon Resonance (Spr) Effect For A Metal-Semiconductor (M-S) Junction At Elevated Temperatures, Erik De Jesus Sanchez

Dissertations and Theses

The effect of temperature increase on the optical excitation of Surface Plasmon Resonance (SPR) at an Ag-Si metal-semiconductor (M-S) junction at a wavelength of 1 . 1 52 pm is investigated theoretically using computer modeling in Fortran. In order to accurately quantify the SPR, the temperature dependent optical constants for Ag and Si are obtained theoretically or semiempirically , using a Drude model for Ag and previous experimentally determined equations for Si (the behavior of the optical constants for crystalline Si and doped Si are found to have very little deviation between each other for our case). An improvement in …

Faculty Senate Monthly Packet November 1993, Portland State University Faculty Senate

Faculty Senate Monthly Packets

The November 1993 Monthly packet includes the November agenda and appendices and the Faculty Senate minutes and attachments from the meeting held October 1993.

Fluttering Fountains: Simplified Models, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Fluttering oscillations are sometimes observed in the falling sheets of water associated with dams and waterfall fountains, and a theoretical simulation of this phenomenon was recently reported. In this study approximate analytical solutions of the previous model are described and compared with the experimental and theoretical observations.

Water Quality Modeling Of The Tualitin River, Christopher John Berger

Dissertations and Theses

Water quality problems related to excessive algal growth, high nutrient loading, and low flows have been occurring along Oregon's Tualatin River. The Tualatin River is 86 miles long and has a drainage basin of 711 square miles. The drainage basin incorporates forest, agricultural, and urban areas. Located in the Portland metropolitan area, these problems have been acerbated by the effects of urban growth. To help analyze pollution control alternatives, a river model study, funded by the Oregon Department of Environmental Quality (DEQ}, was undertaken. An in-stream model of hydraulics and water quality was developed. The Corps of Engineer's CE-QUAL-W2 model, …

Modeling Of Flow And Water Quality In Henry Hagg Lake Near Forest Grove, Oregon, Michael T. Knutson

Dissertations and Theses

Increased population growth in Washington County, Oregon, has helped cause the water quality of the Tualatin River to decline. Henry Hagg Lake is a storage reservoir which was built to augment summer low flows in the Tualatin River. Hagg Lake also supplies the Tualatin River Basin with both irrigation and municipal water in the summer. Using the U.S. Army Corps of Engineer's model CE-QUAL-W2 (a two-dimensional hydrodynamic and water quality model) , a model of Henry Hagg Lake was created. The model was calibrated using water quality and hydraulic data for 1990 at the Hagg Lake outflow in Scoggins Creek. …

Mapping The Distribution Of Vesicular Textures On Silicic Lavas Using The Thermal Infrared Multispectral Scanner, Jaime Ondrusek, Philip R. Christensen, Jonathan Fink

Geology Faculty Publications and Presentations

The Thermal Infrared Multispectral Scanner (TlMS) is a potentially powerful tool for mapping detailed chemical variations in silicic lava flows which in turn could expand knowledge of pre-eruption compositional gradients and mixing processes in silicic magma bodies. However, thermal infrared image data may be greatly influenced by the range of vesicular textures which occur on silicic flows . To investigate the effect of vesicularity on TIMS imagery independent of chemical variations, we studied Little Glass Mountain at the Medicine Lake Volcano of northern California, a large rhyolitic flow of uniform composition but textural heterogeneity. The imagery was recalibrated so that …

Modeling Complex Ecological Economic Systems: Toward An Evolutionary, Dynamic Understanding Of People And Nature, Robert Costanza, Lisa Wainger, Carl Folke, Karl-Göran Mäler

Institute for Sustainable Solutions Publications and Presentations

Recent understanding about system dynamics and predictability that has emerged from the study of complex systems is creating new tools for modeling interactions between anthropogenic and natural systems. A range of techniques has become available through advances in computer speed and accessibility and by implementing a broad, interdisciplinary systems view.

General Education Working Group Report Recommendations, Portland State University. General Education Working Group

University Studies Assessment Research

This report seeks to address several of the questions and concerns raised by faculty at a previous meeting and to more completely set forth the rationale for the goals of the general education program the General Education Working Group recommend.

Data Dependence In Programs Involving Indexed Variables, Borislav Nikolik

Dissertations and Theses

Symbolic execution is a powerful technique used to perform various activities such as program testing, formal verification of programs, etc. However, symbolic execution does not deal with indexed variables in an adequate manner. Integration of indexed variables such as arrays into symbolic execution would increase the generality of this technique. We present an original substitution technique that produces array-term-free constraints as a counterargument to the commonly accepted belief that symbolic execution cannot handle arrays. The substitution technique deals with constraints involving array terms with a single aggregate name, array terms with multiple aggregate names, and nested array terms. Our approach …

Evaluating The Effectiveness Of Certain Metrics In Measuring The Quality Of End User Documentation, Ronald Morrison

Dissertations and Theses

Traditional methods of evaluating quality in computer end user documentation have been subjective in nature, and have not been widely used in practice. Attempts to quantify quality and more narrowly define the essential features of quality have been limited -- leaving the issue of quality largely up to the writer of the user manual.

Quantifiable measures from the literature, especially Velotta (1992) and Brockman (1990), have been assembled into a set of uniformly weighted metrics for the measurement of document quality. This measure has been applied to the end user documentation of eighty-two personal computer packages. End user documentation is …

Orientational Phase Transition In Na_{X}C_{60} (1, T. Yildirim, J. E. Fischer, A. B. Harris, Peter W. Stephens, Dengfa Liu, Laurent Brard, Robert M. Strongin, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

X-ray diffraction and calorimetry data on cubic Na_xC₆₀(1<x60, e.g., T_m(x=1.3)=325 K. The ordered phases are the same as in pure C₆₀: simple cubic, space group Pa3¯, but the orientations in the disordered phase are more restricted. We explain how Na stabilizes the ordered phase to rather high T, while K and Rb do not, in terms of Coulomb interactions between C₆₀ molecules and and Na ions which we calculate from the local charge density of C₆₀.