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Portland State University

2001

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Articles 1 - 30 of 34

Full-Text Articles in Physical Sciences and Mathematics

Dual Heuristic Programming For Fuzzy Control, George G. Lendaris, Thaddeus T. Shannon, Larry J. Schultz, Steven Hutsell, Alec Rogers Dec 2001

Dual Heuristic Programming For Fuzzy Control, George G. Lendaris, Thaddeus T. Shannon, Larry J. Schultz, Steven Hutsell, Alec Rogers

Systems Science Faculty Publications and Presentations

Overview material for the Special Session (Tuning Fuzzy Controllers Using Adaptive Critic Based Approximate Dynamic Programming) is provided. The Dual Heuristic Programming (DHP) method of Approximate Dynamic Programming is described and used to the design a fuzzy control system. DHP and related techniques have been developed in the neurocontrol context but can be equally productive when used with fuzzy controllers or neuro-fuzzy hybrids. This technique is demonstrated by designing a temperature controller for a simple water bath system. In this example, we take advantage of the TSK model framework to initialize the tunable parameters of our plant model with reasonable …


Space-Group Revision For 4-Formylphenylboronic Acid, Frank R. Fronczek, Nadia N. St Luce, Robert M. Strongin Dec 2001

Space-Group Revision For 4-Formylphenylboronic Acid, Frank R. Fronczek, Nadia N. St Luce, Robert M. Strongin

Chemistry Faculty Publications and Presentations

The space group of the title compound, C7H7BO3, previously reported to be P, is properly Cc. There is no disorder of the formyl group or in the H atoms of the B(OH)2 group. Molecules lie on approximate twofold axes and are related by approximate centers, which relate all but the formyl O atom and boronic acid H atoms. The B-O distances are 1.363 (2) and 1.370 (2) Å.


Lower Willamette River Model: Model Calibration, Chris Berger, Robert Leslie Annear, Scott A. Wells Dec 2001

Lower Willamette River Model: Model Calibration, Chris Berger, Robert Leslie Annear, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

Water Environment Services of Clackamas County is in the process of planning upgrades on several of its wastewater treatment plants (WWTPs) which discharge into the Lower Willamette River. The goals of the modeling effort were to:

• Gather data to construct a computer simulation model of the Lower Willamette River system in order to evaluate the impact of the WWTP discharges on water quality

• Ensure that the model accurately represents the system physics and chemistry (flow, temperature, dissolved oxygen and nutrient dynamics) by model calibration

• Use the model to evaluate how to meet various future discharge scenarios for …


Capillary Flow In Interior Corners: The Infinite Column, Mark M. Weislogel Nov 2001

Capillary Flow In Interior Corners: The Infinite Column, Mark M. Weislogel

Mechanical and Materials Engineering Faculty Publications and Presentations

Capillary flow of a sinusoidally perturbed liquid column in an interior corner of infinite extent is solved using lubrication theory. Due primarily to the length scales selected to nondimensionalize the momentum equation, an analytic time scale governing the settling of the perturbation is determined. The time scale, which is shown to be independent of a steady base state flow, proves useful in rapidly predicting transients for surface settling in certain liquid-bearing tanks of spacecraft employing interior corners for fluids management purposes. The asymptotic analysis is extended to address flows along interior corners whose faces are slightly nonplanar. The generalized formulation …


Lower Willamette River Model: Boundary Conditions And Model Setup, Herman G. Rodriguez, Robert Leslie Annear, Scott A. Wells, Chris Berger Nov 2001

Lower Willamette River Model: Boundary Conditions And Model Setup, Herman G. Rodriguez, Robert Leslie Annear, Scott A. Wells, Chris Berger

Civil and Environmental Engineering Faculty Publications and Presentations

Water Environment Services of Clackamas County is in the process of planning upgrades on several of its sewage treatment plants which discharge into the Lower Willamette River. The goals of the modeling effort are to:

• Gather data to construct a computer simulation model of the Lower Willamette River system including part of the Lower Columbia River and the Willamette River above the Oregon City Falls; Because of the tidal influence in the Lower Willamette River, portions of the Columbia River that might affect the Lower Willamette River water quality were also modeled. Also, a section of the Willamette River …


Upper Spokane River Model: Boundary Conditions And Model Setup, 1991 And 2000, Robert Leslie Annear, Chris Berger, Scott A. Wells Nov 2001

Upper Spokane River Model: Boundary Conditions And Model Setup, 1991 And 2000, Robert Leslie Annear, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:

• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam

• Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen and nutrient dynamics)

A hydrodynamic and water quality model, CE-QUAL-W2 Version 3 (Wells, 1997), is being applied …


Dynamical Theory For Modeling Dipole-Dipole Interactions In A Microcavity: The Green Dyadic Approach, P.T. Leung, R. L. Hartman Oct 2001

Dynamical Theory For Modeling Dipole-Dipole Interactions In A Microcavity: The Green Dyadic Approach, P.T. Leung, R. L. Hartman

Physics Faculty Publications and Presentations

A dynamical theory for modeling the dipole-dipole interaction in a microcavity is formulated using the Green dyadic approach. To our knowledge, this theory is one of the most general in many aspects of modeling the phenomenon. It accommodates an arbitrary number of layers adjacent to the cavity, constant but arbitrary dielectric properties within each layer, inclusion of retardation effects, arbitrary dipole orientations, and an unlimited number of interacting dipoles. Numerical results for the emission properties of interacting molecular dipoles in a microcavity are presented to illustrate the capability of the method.


Reifying Communication At The Application Level, Andrew P. Black, Jie Huang, Jonathan Walpole Oct 2001

Reifying Communication At The Application Level, Andrew P. Black, Jie Huang, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Middleware, from the earliest RPC systems to recent Object-Oriented Remote Message Sending (RMS) systems such as Java RMI and CORBA, claims transparency as one of its main attributes. Coulouris et al. define transparency as “the concealment from the … application programmer of the separation of components in a distributed system.” They go on to identify eight different kinds of transparency.

We considered titling this paper “Transparency Considered Harmful”, but that title is misleading because it implies that all kinds of transparency are bad. This is not our view. Rather, we believe that the choice of which transparencies should be offered …


Thermal Activation Between Landau Levels In The Organic Superconductor Β″-(Bedt-Ttf)2sf5ch2cf2so3, Gary L. Gard, M. S. Nam, A. Ardavan, J. A. Symington, J. Singleton, N. Harrison, C. H. Mielke, J. A. Schlueter, Rolf Walter Winter Sep 2001

Thermal Activation Between Landau Levels In The Organic Superconductor Β″-(Bedt-Ttf)2sf5ch2cf2so3, Gary L. Gard, M. S. Nam, A. Ardavan, J. A. Symington, J. Singleton, N. Harrison, C. H. Mielke, J. A. Schlueter, Rolf Walter Winter

Chemistry Faculty Publications and Presentations

We show that Shubnikov–de Haas oscillations in the interlayer resistivity of the organic superconductor β″-(BEDT-TTF)₂SF₅CH₂CF₂SO₃ become very pronounced in magnetic fields ~60T. The conductivity minima exhibit thermally activated behavior that can be explained simply by the presence of a Landau gap, with the quasi-one-dimensional Fermi surface sheets contributing negligibly to the conductivity. This observation, together with complete suppression of chemical potential oscillations, is consistent with an incommensurate nesting instability of the quasi-one-dimensional sheets.


Signature Lipids And Stable Carbon Isotope Analyses Of Octopus Spring Hyperthermophilic Communities Compared With Those Of Aquificales Representatives, Linda L. Jahnke, Wolfgang Eder, Robert Huber, Janet M. Hope, Kai-Uwe Hinrichs, John M. Hayes, David J. Des Marais, Sherry L. Cady, Roger E. Summons Aug 2001

Signature Lipids And Stable Carbon Isotope Analyses Of Octopus Spring Hyperthermophilic Communities Compared With Those Of Aquificales Representatives, Linda L. Jahnke, Wolfgang Eder, Robert Huber, Janet M. Hope, Kai-Uwe Hinrichs, John M. Hayes, David J. Des Marais, Sherry L. Cady, Roger E. Summons

Geology Faculty Publications and Presentations

The molecular and isotopic compositions of lipid biomarkers of cultured Aquificales genera have been used to study the community and trophic structure of the hyperthermophilic pink streamers and vent biofilm from Octopus Spring. Thermocrinis ruber, Thermocrinis sp. strain HI 11/12, Hydrogenobacter thermophilus TK-6, Aquifex pyrophilus, and Aquifex aeolicus all contained glycerol-ether phospholipids as well as acyl glycerides. The n-C20:1 and cy-C21 fatty acids dominated all of the Aquificales, while the alkyl glycerol ethers were mainly C18:0. These Aquificales biomarkers were major constituents of the lipid extracts of two Octopus Spring samples, a biofilm associated with the siliceous vent walls, and …


Snags In Beaver Ponds And Indications Of Use By Primary Cavity-Nesting Birds In The Western Oregon Cascades, Jacqueline I. Fern Jul 2001

Snags In Beaver Ponds And Indications Of Use By Primary Cavity-Nesting Birds In The Western Oregon Cascades, Jacqueline I. Fern

Dissertations and Theses

Dead trees, or snag , are used by primary cavity-nesting birds for nesting, foraging, and roosting and are essential habitat for the e species. Snags formed in beaver ponds due to flooded conditions are utilized by a variety of woodpecker species. In this study I quantified and compared snag density, size, decay characteristics, and excavations in beaver ponds and in forested riparian sites without beaver influence (reference sites) in the western Oregon Cascades. Beaver ponds were treated as a pooled group (n=8) and also categorized into old (n=5) and new (n=3) classes based on decay indicators. Reference sites (n=8) were …


Stochastic Properties Of Spacings In A Single-Outlier Exponential Model, Baha-Eldin Khaledi, Subhash C. Kochar Jul 2001

Stochastic Properties Of Spacings In A Single-Outlier Exponential Model, Baha-Eldin Khaledi, Subhash C. Kochar

Mathematics and Statistics Faculty Publications and Presentations

Let X1,..., Xn be independent exponential random variables with possibly different scale parameters. Kochar and Korwar [J. Multivar. Anal. 57 (1996)] conjectured that, in this case, the successive normalized spacings are increasing according to hazard rate ordering. In this article, we prove this conjecture in the case of a single-outlier exponential model when all except one of the parameters are identical. We also prove that the spacings are more dispersed and larger in the sense of hazard rate ordering when the vector of scale parameters is more dispersed in the sense of majorization.


An Information Theoretic Methodology For Prestructuring Neural Networks, Bjorn Chambless, George G. Lendaris, Martin Zwick Jul 2001

An Information Theoretic Methodology For Prestructuring Neural Networks, Bjorn Chambless, George G. Lendaris, Martin Zwick

Systems Science Faculty Publications and Presentations

Absence of a priori knowledge about a problem domain typically forces use of overly complex neural network structures. An information-theoretic method based on calculating information transmission is applied to training data to obtain a priori knowledge that is useful for prestructuring (reducing complexity) of neural networks. The method is applied to a continuous system, and it is shown that such prestructuring reduces training time, and enhances generalization capability.


Oregon Aquatic Nuisance Species Management Plan, Erik Hanson, Mark Sytsma Jun 2001

Oregon Aquatic Nuisance Species Management Plan, Erik Hanson, Mark Sytsma

Center for Lakes and Reservoirs Publications and Presentations

Aquatic Nuisance Species (ANS) are a serious problem in Oregon. There are currently over 134 nonindigenous aquatic species reported in Oregon. More species are expected to arrive. Current state activities and authorities address some ANS, their prevention, and control. Yet, the activities are not coordinated or comprehensively managing the impacts of ANS. The importance of Oregon’s aquatic resources requires a coherent response to the threat posed by ANS. This management plan is the initial step in establishing a program in Oregon to specifically address ANS issues.


Visions, Values, Valuation And The Need For An Ecological Economics, Robert Costanza Jun 2001

Visions, Values, Valuation And The Need For An Ecological Economics, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Practical problem solving in complex, humandominated ecosystems requires the integration of three elements: (1) active and ongoing envisioning of both how the world works and how we would like the world to be, (2) systematic analysis appropriate to and consistent with the vision, and (3) implementation appropriate to the vision. Scientists generally focus on only the second of these steps, but integrating all three is essential to both good science and effective management. Subjective values enter in the vision element, both in terms of the formation of broad social goals and in the creation of a preanalytic vision,which necessarily precedes …


Globally Convergent Approximate Dynamic Programming Applied To An Autolander, J.J. Murray, Richard Saeks, C.J. Cox, George G. Lendaris Jun 2001

Globally Convergent Approximate Dynamic Programming Applied To An Autolander, J.J. Murray, Richard Saeks, C.J. Cox, George G. Lendaris

Systems Science Faculty Publications and Presentations

A globally convergent nonlinear Approximate Dynamic Programming algorithm is described, and an implementation of the algorithm in the linear case is developed. The resultant linear Approximate Dynamic Programming algorithm is illustrated via the design of an autolander for the NASA X-43 research aircraft, without a priori knowledge of the X-43's flight dynamics.


Meyer-Neldel Rule For Dark Current In Charge-Coupled Devices, Ralf Widenhorn, Lars Mündermann, Armin Rest, Erik Bodegom Jun 2001

Meyer-Neldel Rule For Dark Current In Charge-Coupled Devices, Ralf Widenhorn, Lars Mündermann, Armin Rest, Erik Bodegom

Physics Faculty Publications and Presentations

We present the results of a systematic study of the dark current in each pixel of a charged-coupled device chip. It was found that the Arrhenius plot, at temperatures between 222 and 291 K, deviated from a linear behavior in the form of continuous bending. However, as a first approximation, the dark current, D, can be expressed as: D=Dₒ exp(−ΔE/kT),where ΔE is the activation energy, k is Boltzmann’s constant, and T the absolute temperature. It was found that ΔE and the exponential prefactor Dₒ follow the Meyer–Neldel rule (MNR) for all of the more than 222,000 investigated pixels. The isokinetic …


Infopipes—An Abstraction For Information Flow, Jie Huang, Andrew P. Black, Jonathan Walpole, Calton Pu Jun 2001

Infopipes—An Abstraction For Information Flow, Jie Huang, Andrew P. Black, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

Building Object-Oriented Distributed Systems has been facilitated by Remote Message Sending (RMS) systems like Java RMI and implementations of CORBA. However, RMS systems are designed to support request/response interactions. Streaming applications, in contrast, are characterized by high-bandwidth, long-duration communication with stringent performance requirements. Examples of streaming applications include video-on-demand, teleconferencing, on-line education, and environmental observation. These applications transfer huge amounts of data and focus on distributed information flow rather than request/response.

To simplify the task of building distributed streaming applications, we propose a new abstraction for information flow—Infopipes. Using Infopipes, information flow becomes the heart of the system, not an …


Government Sponsored Perversity. Review Of: Perverse Subsidies: How Tax Dollars Can Undercut The Environment And The Economy By Norman Myers And Jennifer Kent, Robert Costanza May 2001

Government Sponsored Perversity. Review Of: Perverse Subsidies: How Tax Dollars Can Undercut The Environment And The Economy By Norman Myers And Jennifer Kent, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Book review of Perverse Subsidies: How Tax Dollars Can Undercut the Environment and the Economy. Norman Myers and Jennifer Kent. Island Press, Washington (DC), 2001.


Trimethylsulfonium Methanesulfonate, Frank R. Fronczek, Rolanda J. Johnson, Robert M. Strongin May 2001

Trimethylsulfonium Methanesulfonate, Frank R. Fronczek, Rolanda J. Johnson, Robert M. Strongin

Chemistry Faculty Publications and Presentations

In the title compound, C3H9S+.CH3O3S-, a thermal decomposition product of dimethyl sulfoxide, both cation and anion lie on mirror planes. In the cation, the S atom lies 0.792 (2) Å out of the plane defined by the three C atoms, with S-C distances of 1.781 (2) and 1.786 (3) Å. In the anion, the S-O distances are 1.4556 (14) and 1.4646 (19) Å, and the S-C distance is 1.759 (3) Å.


Seasonal Patterns Of Photosynthesis In Douglas Fir Seedlings During The Third And Fourth Year Of Exposure To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey May 2001

Seasonal Patterns Of Photosynthesis In Douglas Fir Seedlings During The Third And Fourth Year Of Exposure To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

The interactive effects of elevated atmospheric CO2 and temperature on seasonal patterns of photosynthesis in Douglas fir (Psuedotsuga menziesii (Mirb.) Franco) seedlings were examined. Seedlings were grown in sunlit chambers controlled to track either ambient (~400 p.p.m.) CO2 or ambient +200 p.p.m. CO2, and either ambient temperature or ambient +4 °C. Light-saturated net photosynthetic rates were measured approximately monthly over a 21 month period. Elevated CO2 increased net photosynthetic rates by an average of 21% across temperature treatments during both the 1996 hydrologic year, the third year of exposure, and the 1997 hydrologic year. Elevated …


Building A Sustainable Future For Portland, City Club Of Portland (Portland, Or.) Apr 2001

Building A Sustainable Future For Portland, City Club Of Portland (Portland, Or.)

City Club of Portland

No abstract provided.


Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu Mar 2001

Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

This paper uses hybrid control to model a problem of computer network systems, the dynamic behavior of bandwidth sharing among competing TCP traffic. It has been well known in the computer network community that well-behaved (TCP-friendly) congestion control mechanisms are crucial to the robustness of the Internet. Congestion control determines the transmission rate for each flow. Right now, most TCP-friendly research focuses only on the average throughput behavior without considering how the data is sent out in the short-term (e.g. bursty or smooth). However, recent experimental results show that short-term rate adjustments can change the bandwidth sharing result. Therefore, it …


Infosphere Project: An Overview, Calton Pu, Jonathan Walpole Mar 2001

Infosphere Project: An Overview, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We describe the Infosphere project, which is building the systems software support for information-driven applications such as digital libraries and electronic commerce. The main technical contribution is the Infopipe abstraction to support information flow with quality of service. Using building blocks such as program specialization, software feedback, domain-specific languages, and personalized information filtering, the Infopipe software generates code and manage resources to provide the specified quality of service with support for composition and restructuring.


Moving Towards Massively Scalable Video-Based Sensor Networks, Wu-Chi Feng, Jonathan Walpole, Calton Pu, Wu-Chang Feng Mar 2001

Moving Towards Massively Scalable Video-Based Sensor Networks, Wu-Chi Feng, Jonathan Walpole, Calton Pu, Wu-Chang Feng

Computer Science Faculty Publications and Presentations

Networking and computing technologies are becoming advanced enough to enable a wealth of diverse applications that will drastically change our everyday lives. Some past examples of these developments include the World Wide Web and wireless data networking infrastructures. As is quite obvious, the World Wide Web has enabled a fundamental change in the way many people deal with day-to-day tasks. Through the web, one can now make on-line reservations for travel, pay bills through on-line banking services, and view personalized on-line newscasts. More recently, developments in wireless technologies have enabled anywhere, anytime access to information over wireless medium. As wireless …


Economics As A Life Science: Review Of You Can't Eat Gnp: Economics As If Ecology Mattered By Eric A. Davidson And The Nature Of Economies By Jane Jacobs, Robert Costanza Feb 2001

Economics As A Life Science: Review Of You Can't Eat Gnp: Economics As If Ecology Mattered By Eric A. Davidson And The Nature Of Economies By Jane Jacobs, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Two Book Reviews: You Can?t Eat GNP: Economics As If Ecology Mattered by Eric A. Davidson and The Nature of Economies by Jane Jacobs


The Multiplicities Of A Dual-Thin Q-Polynomial Association Scheme, Bruce E. Sagen, John S. Caughman Iv Jan 2001

The Multiplicities Of A Dual-Thin Q-Polynomial Association Scheme, Bruce E. Sagen, John S. Caughman Iv

Mathematics and Statistics Faculty Publications and Presentations

Let Y=(X,{Ri}1≤iD) denote a symmetric association scheme, and assume that Y is Q-polynomial with respect to an ordering E0,...,ED of the primitive idempotents. Bannai and Ito conjectured that the associated sequence of multiplicities mi (0≤iD) of Yis unimodal. Talking to Terwilliger, Stanton made the related conjecture that mimi+1 and mimDi for i<D/2. We prove that if Y is dual-thin in the sense of Terwilliger, then the …


Post-Stagnation Behavior In The Upstream Regions Of Ice Stream C, West Antarctica, Stephen F. Price, R. A. Bindschadler, Christina L. Hulbe, Ian R. Joughin Jan 2001

Post-Stagnation Behavior In The Upstream Regions Of Ice Stream C, West Antarctica, Stephen F. Price, R. A. Bindschadler, Christina L. Hulbe, Ian R. Joughin

Geology Faculty Publications and Presentations

The region where two active tributaries feed into the now stagnant Ice Stream C (ISC), West Antarctica, is thickening. In this region, we observe a correlation between faster ice flow (the tributaries) and elevated topography. We conclude that stagnation of ISC resulted in compression and thickening along the tributaries, eventually forming a "bulge" on the ice-sheet surface. Modern hydraulic potential gradients would divert basal meltwater from ISC to Ice Stream B (ISB). These gradients are primarily controlled by the bulge topography, and so likely formed subsequent to trunk stagnation. As such, we argue against "water piracy" as being the cause …


The Impact Of Fine Sediment On Stream Macroinvertebrates In Urban And Rural Oregon Streams, Raymond S. Hoy Jan 2001

The Impact Of Fine Sediment On Stream Macroinvertebrates In Urban And Rural Oregon Streams, Raymond S. Hoy

Dissertations and Theses

Urbanization, often characterized by high impervious surface area, can result in excessive inputs of fine sediments into urban streams. Excessive fine sediments can blanket the stream bed filling the interstitial space in the substratum, which may have adverse effects on stream biota. A field survey was conducted in Oregon urban and non-urban basins to investigate the relationship between fine sediments and stream macroinvertebrates. Physical, chemical, and biological data were collected from 59 stream sites in two urban and two rural streams. The stream sites fulfilled a continuous sediment gradient, which ranged from a low of 2% of fine sediment in …


Wholes And Parts In General Systems Methodology, Martin Zwick Jan 2001

Wholes And Parts In General Systems Methodology, Martin Zwick

Systems Science Faculty Publications and Presentations

Reconstructability analysis (RA) decomposes wholes, namely data in the form either of set-theoretic relations or multivariate probability distributions, into parts, namely relations or distributions involving subsets of variables. Data is modeled and compressed by variablebased decomposition, by more general state-based decomposition, or by the use of latent variables. Models, which specify the interdependencies among the variables, are selected to minimize error and complexity.