Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Portland State University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 7411 - 7440 of 8690

Full-Text Articles in Entire DC Network

Portals - The Portland Area Library System: The Promise Of A Virtual Research Library, Gretta E. Siegel Dec 1993

Portals - The Portland Area Library System: The Promise Of A Virtual Research Library, Gretta E. Siegel

Library Faculty and Staff Publications and Presentations

About a year ago, someone from eastern Washington phoned and asked me about PORTALS. He was working with a group of libraries who were building a consortium and thought that PORTALS would be a good model to look at. I was a bit perplexed - yes, I was involved with PORTALS, but the problem was, it didn't really exist as anything that I could, point to and say, here, this is PORTALS. Now, a year later, I can proudly say that we have indeed metamorphosed into something identifiable, though the evolution continues. This article will attempt to describe what PORTALS …


Modeling And Simulation Of Bipolar Transistor At Low Temperature, Swarupa Madhav Nerurkar Nov 1993

Modeling And Simulation Of Bipolar Transistor At Low Temperature, Swarupa Madhav Nerurkar

Dissertations and Theses

The BICMOS technology which integrates the CMOS technology with bipolar technology has drawn considerable attention as an attractive VLSI technology because of the high speed performance and low power consumption of the BICMOS. However, continued down scaling of CMOS devices has caused increased concerns with problems such as latch up, hot carriers and short channel effect. Most of the above mentioned problems can be avoided by operating the CMOS at liquid-nitrogen temperature(LNT). At low-temperatures, the CMOS exhibits lower sub threshold leakage, higher carrier mobility (which yields improved speed performance), and a steeper logarithmic currentvoltage slope. On the other hand, the …


Pattern Recognition And Erp Waveform Analysis Using Wavelet Transform, Hong Qi Nov 1993

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 …


Investigation Of Solution Space Of Trees And Dags For Realization Of Combinational Logic In At 6000 Series Fpgas, Philip Ho Nov 1993

Investigation Of Solution Space Of Trees And Dags For Realization Of Combinational Logic In At 6000 Series Fpgas, Philip Ho

Dissertations and Theses

Various tree and Directed Acyclic Graph structures have been used for representation and manipulation of switching functions. Among these structures the Binary Decision Diagrams have been the most widely used in logic synthesis. A BDD is a binary tree graph that represents the recursive execution of Shannon's expansion. A FDD is a directed function graph that represents the recursive execution of Reed Muller expansion.

A family of decision diagrams for representation of Boolean function is introduced in this thesis. This family of Kronecker Functional Decision Diagrams (KFDD) includes the Binary Decision Diagrams (BDD) and Functional Decision Diagrams (FDD) as subsets. …


Determining The Property Value Impact Of Landfills, Okwuchukwu Gerald Uba Nov 1993

Determining The Property Value Impact Of Landfills, Okwuchukwu Gerald Uba

Dissertations and Theses

The decline in property value can be due to owner's act or exogenous act from the operation of landfills. Landfill neighbors, especially home owners, perceive landfill operation to pose environmental safety problem such as ground water contamination and methane gas leakage that could affect home value.

Owners of landfills, especially those landfills that accept only dry waste (limited purpose landfill), claim that since their facilities meet the requirements of environmental regulations and the type of waste they accept could not possibly produce methane gas and leachate there is no property value impact of their facilities.

Several studies have shown that …


Vertex Ordering For A Partitioning-Based Fitting Algorithm For An Epld Device, Tongjun Gao Nov 1993

Vertex Ordering For A Partitioning-Based Fitting Algorithm For An Epld Device, Tongjun Gao

Dissertations and Theses

As the Application-Specific Integrated Circuit(ASIC) technology develops to the trend of high density and modulization, the ASIC device market has been dominated gradually by the more complex Erasable Programmable Logic Devices (EPLDs) and the Field Programmable Gate Array(FPGAs) instead of the ordinally Programmable Logic Devices(PLDs). Meanwhile, the design automation system for such programmable devices has also moved from schematic entry design to high level hardware description language entry design. Usually, the whole design automation process consists of three phrases, the high level hardware description language compiler, the logic synthesis stage and the layout synthesis stage. Though the layout synthesis stage …


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

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.


Simulation Of Switched Linear Networks, Dietmar Reinhard Skowronn Oct 1993

Simulation Of Switched Linear Networks, Dietmar Reinhard Skowronn

Dissertations and Theses

This thesis deals with the time-domain analysis of switched linear networks and investigates inherent problems which have to be considered when analyzing this class of networks. Computer simulation requires the use of numerical methods and we focus on the transmission -line modelling technique (TLM) and the numerical inverse Laplace transform. A general approach based on the one-graph modified nodal description is given which allows the formulation of circuit equations of a TLM-modelled circuit by inspection. The numerical equivalence of TLM and trapezoidal rule has been found and a proof is given. A variable step size simulator has been developed based …


Fluttering Fountains: Simplified Models, Lee W. Casperson Oct 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.


Cost And Benefit Elements Of A Tailored Application Versus An Off-The-Shelf Package And The Manager's Role., Fernando E. Rivera Oct 1993

Cost And Benefit Elements Of A Tailored Application Versus An Off-The-Shelf Package And The Manager's Role., Fernando E. Rivera

Engineering and Technology Management Student Projects

The author of the paper performs a cost-benefit analysis to determine whether to make or buy a software package. If a program is developed in house, whatever the organizational Software Department could have accomplished during the time it spent developing the system is determined. However, adoption of an off-the shelf package means that the benefits of having a "perfect" package will be lost. The opportunity cost would be an estimate of those benefits lost over the period the software packaging is to be used, minus the additional expenses involved in developing a "perfect" package.


A Study Of Spiking And Relaxation Oscillations In Nd:Yag Laser Using Measured Laser Parameters, Ramesh K. Shori Sep 1993

A Study Of Spiking And Relaxation Oscillations In Nd:Yag Laser Using Measured Laser Parameters, Ramesh K. Shori

Dissertations and Theses

It was shown analytically and experimentally that when the cavity losses are perturbed, the output intensity experiences an amplitude modulation or becomes a regular train of spikes, with the frequency depending on both the frequency of perturbation as well as pump power. Coupled nonlinear rate equations including the cavity perturbation term, are solved numerically by a Runga-Kutta method using experimentally-measured parameter values for Nd: Y AG laser. A continuously pumped Nd: Y AG laser was used to verify this theory.


Water Quality Modeling Of The Tualitin River, Christopher John Berger Sep 1993

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 Sep 1993

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. …


Meeting Notes 1993-09-09 , Joint Policy Advisory Committee On Transportation Sep 1993

Meeting Notes 1993-09-09 , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.


Portland State Magazine, Portland State University. Office Of University Communications Sep 1993

Portland State Magazine, Portland State University. Office Of University Communications

Portland State Magazine

PSU’s alumni magazine, published 2-3 times a year. In this issue: This physics grad can determine if a missile warhead contains nerve gas or if an egg is infected with salmonella; a PSU psychology professor is asking Portland’s gay men about their relationships, feelings, and sex lives; for the past 20 years Jame Maurer has been bringing hearing technology to Costa Rica; and more.


Meeting Notes 1993-08-12 , Joint Policy Advisory Committee On Transportation Aug 1993

Meeting Notes 1993-08-12 , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.


A Cognitively Motivated System For Software Component Reuse, Michael Joseph Mateas Jul 1993

A Cognitively Motivated System For Software Component Reuse, Michael Joseph Mateas

Dissertations and Theses

Software reuse via component libraries suffers from the twin problems of code location and comprehension. The Intelligent Code Object Planner (ICOP) is a cognitively motivated system that facilitates code reuse by answering queries about how to produce an effect with the library. It can plan for effects which are not primitive with respect to the library by building a plan that incorporates multiple components. The primary subsystems of ICOP are a knowledge base which describes the ontology of the library, a natural language interface which translates user queries into a formal effect language (predicates), a planner which accepts the effect …


Automatic Tuning Of Integrated Filters Using Neural Networks, Lutz Henning Lenz Jul 1993

Automatic Tuning Of Integrated Filters Using Neural Networks, Lutz Henning Lenz

Dissertations and Theses

Component values of integrated filters vary considerably due to· manufacturing tolerances and environmental changes. Thus it is of major importance that the components of an integrated filter be electronically tunable. The method explored in this thesis is the transconductance-C-method.

A method of realizing higher-order filters is to use a cascade structure of second-order filters. In this context, a method of tuning second-order filters becomes important.

The research objective of this thesis is to determine if the Neural Network methodology can be used to facilitate the filter tuning process for a second-order filter (realized via the transconductance-C-method). Since this thesis is, …


Unified Bias Analysis Of Subspace-Based Doa Estimation Algorithms, Yang Lu Jul 1993

Unified Bias Analysis Of Subspace-Based Doa Estimation Algorithms, Yang Lu

Dissertations and Theses

This thesis presents the unified bias analysis of subspace-based DOA estimation algorithms in terms of physical parameters such as source separation, signal coherence, number of senors and snapshots. The analysis reveals the direct relationship between the performance of the DOA algorithms and signal measurement conditions. Insights into different algorithms are provided. Based upon previous first-order subspace perturbations, second-order subspace perturbations are developed which provide basis for bias analysis and unification. Simulations verifying the theoretical bias analysis are presented.


Meeting Notes 1993-07-08 [Part B] , Joint Policy Advisory Committee On Transportation Jul 1993

Meeting Notes 1993-07-08 [Part B] , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.


Meeting Notes 1993-07-08 [Part A] , Joint Policy Advisory Committee On Transportation Jul 1993

Meeting Notes 1993-07-08 [Part A] , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.


Detecting Chaotic Signals With Nonlinear Models, Qin Cai Jul 1993

Detecting Chaotic Signals With Nonlinear Models, Qin Cai

Dissertations and Theses

In this thesis we apply chaotic dynamic data analysis to the area of discrete time signal processing. A newly developed Hidden Filter Hidden Markov Model is introduced in detection of chaotic signals. Numerical experiments have verified that this novel nonlinear model outperforms linear AR model in detecting chaotic signals buried by noise having similar power spectra. A simple Histogram Model is proposed which can also be used to do detection on the data sets with chaotic behavior. Receiver Operating Characteristics for a variety of noise levels and model classes are reported.


A New Approach To The Optimal Filtering Of Differential Phase Measurements Of Gps Signal In The Precision Survey, Shengan Wang Jul 1993

A New Approach To The Optimal Filtering Of Differential Phase Measurements Of Gps Signal In The Precision Survey, Shengan Wang

Dissertations and Theses

The Global Positioning System (GPS) has become popular research and application interests in surveying and many other areas. Nowadays, the accuracy of the Differential GPS can easily reach the order of a few meters. Yet, there are still many ways to exploit the GPS system signal carrier to improve the accuracy to less than meter level. In this thesis, a new approach to improve the accuracy to less than meter level is presented while the observer is in the dynamic situation. In order to reach the sub-meter accuracy, we measure on the carrier phase difference (The L1 carrier frequency is …


The Intellectual Grounding Of The San Francisco Committee Of Vigilance Of 1851, Jon Jeffrey Walker Jul 1993

The Intellectual Grounding Of The San Francisco Committee Of Vigilance Of 1851, Jon Jeffrey Walker

Dissertations and Theses

Vigilantism has a long history in the United States stretching back to the Regulator movement in South Carolina in 1767. These extralegal movements are distinguished from spontaneous and ephemeral mob activity by their regular organization and limited life-span. The San Francisco Committee of Vigilance of 1856 was the largest vigilante movement in American history. After a summer of vigilantism that included four hangings, the committee turned to politics and formed the People's Party which dominated San Francisco's city government for the next decade. The 1856 committee is generally considered the great exemplar of American vigilantism and has received considerable attention …


Scattering Of A Light Beam From Waves At An Air-Sea Interface, Donald D. Duncan, W. H. Carter Jun 1993

Scattering Of A Light Beam From Waves At An Air-Sea Interface, Donald D. Duncan, W. H. Carter

Electrical and Computer Engineering Faculty Publications and Presentations

The authors report a new theory that describes the scattering of an upward propagating laser beam from the sea through the air-sea interface in the presence of sea waves. The sea is assumed to be a uniform dielectric and conventional scattering theory is employed by using a modification to the first Born approximation that permits treatment of surface refraction phenomena. Methods of statistical radiometry are also used in a new manner by assuming that the surface scattering function for the sea waves can be treated by a quasi-homogeneous source model to calculate the second-order correlation functions for the partially coherent …


Predicting Seepage Of Leachate From The St. Johns Landfill To Ground And Surface Water Systems, Kevin A. Schock Jun 1993

Predicting Seepage Of Leachate From The St. Johns Landfill To Ground And Surface Water Systems, Kevin A. Schock

Dissertations and Theses

Determination of the vertical and horizontal groundwater hydraulic gradient within a landfill is the first step in determining the potential of groundwater contamination from the landfill leachate. The length of a study and the frequency at which measurements are recorded can greatly affect the description of the local groundwater environment. A more comprehensive analysis can be preformed for longer periods of study and greater measurement frequency. The intent of this study was to install a continuous groundwater level monitoring system around the st. Johns Landfill for a minimum study length of one year. This would allow a more thorough study …


Meeting Notes 1993-06-10 , Joint Policy Advisory Committee On Transportation Jun 1993

Meeting Notes 1993-06-10 , Joint Policy Advisory Committee On Transportation

Joint Policy Advisory Committee on Transportation

No abstract provided.


Waveform Estimation With Jitter Noise By Pseudo Symmetrical Probability Density Function, Wei-Da Hao Jun 1993

Waveform Estimation With Jitter Noise By Pseudo Symmetrical Probability Density Function, Wei-Da Hao

Dissertations and Theses

A new method for solving jitter noise in estimating high frequency waveform is proposed. It reduces the bias of the estimation in those points where all the other methods fail to achieve. It provides preliminary models for estimating percentiles in Normal, Exponential probability density function. Based on the model for Normal probability density function, a model for any probability density function is derived. The resulting percentiles, in turn, are used as estimates for the amplitude of the waveform. Simulation results show us with satisfactory accuracy.


Performance Analysis Of A Hierarchical, Cache-Coherent, Shared Memory Based, Multi-Processor System, Raman Nayyar Jun 1993

Performance Analysis Of A Hierarchical, Cache-Coherent, Shared Memory Based, Multi-Processor System, Raman Nayyar

Dissertations and Theses

We have conducted a performance analysis of a large scale multiprocessor system based on shared buses organized in a hierarchical fashion and employing an easy to implement snoopy cache protocol. · This arrangement, named TREEBUS [ 5], presents a logical extension path for multiprocessor systems based on a single shared bus whose scalability is limited by the available system bus bandwidth [26]. The multiple, independent, hierarchical buses overcome the bus bandwidth limitation and the architecture can scale to relatively large sizes. We have developed an easy to use, reasonably accurate and computationally efficient analytic model for analyzing the performance of …


Faculty Senate Monthly Packet June 1993, Portland State University Faculty Senate Jun 1993

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

Faculty Senate Monthly Packets

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