Digital Commons Network^™

Signal Velocity In Oscillator Arrays, Carlos E. Cantos, David K. Hammond, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We investigate a system of coupled oscillators on the circle, which arises from a simple model for behavior of large numbers of autonomous vehicles. The model considers asymmetric, linear, decentralized dynamics, where the acceleration of each vehicle depends on the relative positions and velocities between itself and a set of local neighbors. We first derive necessary and sufficient conditions for asymptotic stability, then derive expressions for the phase velocity of propagation of disturbances in velocity through this system. We show that the high frequencies exhibit damping, which implies existence of well-defined signal velocities c+>0 and c−f(x−c+t) in the direction …

3d Hydrodynamic Model Development And Verification, Hussein A. M. Al-Zubaidi

Civil and Environmental Engineering Master's Project Reports

A three-dimensional numerical model was developed to simulate hydrodynamic, temperature, and water quality distributions in rivers and lakes. In an attempt to get rid of the extra approximation and complexity, no coordinate transformation has been done and z-coordinate system has been employed. The governing equations are the continuity equation, free surface equation, momentum equations, and conservation equations of temperature and water quality. The model employs the time splitting technique which allows splitting the directions in which we end with two-dimensional governing equations and eventually the solution ends with a tri-diagonal matrix, which is easily solved by Thomas algorithm. The first …

Structural Design Issues Of "Hexapod" Foundations For Wind Turbine Towers, Chad A. Norvell

Civil and Environmental Engineering Master's Project Reports

The current practice for wind turbine foundations is to use massive cast-in-place concrete spread footings or complex pile-supported foundations. Wind turbine generator components and the towers that support them are pre-fabricated and assembled on site, leaving the foundation as the only component of the wind turbine system requiring major in situ construction. The new "hexapod" foundation concept is fully pre-fabricated, uses a fraction of the quantity of concrete used in conventional foundations, and may be dismantled and re-used elsewhere. The wind turbine tower is attached to a steel or concrete hub which is attached to six radial, precast, post-tensioned concrete …

A Study On The Current State Of Contaminants Of Concern Research, With A Focus On Biosolids And Regulations, Maren Mariah Fulton

Civil and Environmental Engineering Master's Project Reports

Wastewater treatment plants are a major source of contaminants of emerging concern, as these facilities are the main receptors of these products via household, commercial, and industrial drains, and transport via stormwater runoff. Biosolids are composed of numerous constituents, with a number of environmentally persistent and potentially toxic contaminants of emerging concern identified as present in large concentrations. Research is needed to understand the transport and fate mechanisms of these compounds in biosolids. Additionally, this research is needed to determine a new priority framework to regulate CECs, both on the national level and regional levels. Wastewater treatment plant influent and …

Curriculum Change 2016-2017, Portland State University

Bulletin & Curriculum Change Documents

No abstract provided.

Madagascar’S Mangroves: Quantifying Nation-Wide And Ecosystem Specific Dynamics, And Detailed Contemporary Mapping Of Distinct Ecosystems, Trevor G. Jones, Leah Glass, Samir Gandhi, Lalao Ravaoarinorotsihoarana, Aude Carro, Lisa Benson, Harifidy Rakoto Ratsimba, Chandra Giri, Dannick Randriamanatena, Garth Cripps

Environmental Science and Management Faculty Publications and Presentations

Mangrove ecosystems help mitigate climate change, are highly biodiverse, and provide critical goods and services to coastal communities. Despite their importance, anthropogenic activities are rapidly degrading and deforesting mangroves world-wide. Madagascar contains 2% of the world’s mangroves, many of which have undergone or are starting to exhibit signs of widespread degradation and deforestation. Remotely sensed data can be used to quantify mangrove loss and characterize remaining distributions, providing detailed, accurate, timely and updateable information. We use USGS maps produced from Landsat data to calculate nation-wide dynamics for Madagascar’s mangroves from 1990 to 2010, and examine change more closely by partitioning …

Three Simple Experiments To Examine The Effect Of Sediment Pollution On Algae-Based Food Webs In Streams, Patrick M. Edwards, Rodney Shroufe

Environmental Science and Management Faculty Publications and Presentations

Streams and stream macroinvertebrates are ideal natural systems for ecological inquiry. We present three simple experiments that students can use to conduct field-based investigations which illustrate the importance of algae-based food webs in streams and measure the effects of sediment pollution (scour and deposition) on stream ecological processes. Over the past 5 years, we have conducted these experiments 19 times with our students. We report on the results and reliability of these experiments and make suggestions for other educators who may want to conduct them.

Resident Perceptions Of Natural Resources Between Cities And Across Scales In The Pacific Northwest, Anita T. Morzillo, Betty J. Kreakie, Noelwah R. Netusil, J. Alan Yeakley

Environmental Science and Management Faculty Publications and Presentations

As the global population becomes increasingly urban, research is needed to explore how local culture, land use, and policy will influence urban natural resource management. We used a broad-scale comparative approach and survey of residents within the Portland (Oregon)-Vancouver (Washington) metropolitan areas, USA, two states with similar geographical and ecological characteristics, but different approaches to land-use planning, to explore resident perceptions about natural resources at three scales of analysis: property level (“at or near my house”), neighborhood (“within a 20-minute walk from my house”), and metro level (“across the metro area”). At the metro-level scale, nonmetric multidimensional scaling revealed that …

The Effects Of The Aca On Actuarial Pricing: How The Work Of Health Actuaries Has Changed Post-Aca, Alex M.S. George

University Honors Theses

In the United States, the Patient Protection and Affordable Care Act (PPACA or ACA) drastically altered the health insurance industry. Insurers are no longer able to deny coverage or charge higher premiums based on an individual’s medical history. In order to more evenly spread the financial risks associated with these ACA reforms among insurers and stabilize health insurance premiums, risk-sharing provisions dubbed the "3 R's" (risk adjustment, risk corridors, and reinsurance) were instituted in the individual and small group market. This thesis will begin with a discussion of the "3 R's" and the other ACA regulations that have had significant …

Understanding Multiple Sclerosis Through Retinal Cell Layer Thickness: An Insight Into The Neurodegeneration Process, Zac Festner

University Honors Theses

Patients with multiple sclerosis (MS) have long been known to suffer deterioration of the retina, sometimes leading to blindness. The damage has been assumed to occur predominantly within the retinal nerve fiber layer. Using optical coherence tomography (OCT), researchers at Johns Hopkins University have determined that there is a subset of MS patients for whom the retinal deterioration is different. For this group the deterioration occurs at a deeper level within the retina, between the photoreceptors and the connecting cells. This deterioration affects the inner and outer nuclear layers of the retina. These findings are perplexing, as MS is considered …

Teaching The Middle East In Portland Public High Schools, Nicholas C. Jenkins

University Honors Theses

This paper examines the ways in which the Middle East is taught to high school students in Portland Public School. Specifically, it focuses on the required history courses, Modern World History and United States History for Freshman and Juniors, respectively. Beginning with a definition of the Middle East, this paper starts by placing itself and the author within a discourse community of educators, historians, and writers who discuss the issues with incorporating multiple points of view into their curriculum. After a discussion of the methods by which the data was collected, this paper concludes by offering a description of that …

A Numerical Modeling Investigation On Calving And The Recession Of South Cascade Glacier, Annika Noel Horlings

University Honors Theses

Retreat of South Cascade Glacier has been well documented since 1957. Despite this, little research has examined why South Cascade Glacier has receded more rapidly than other glaciers in the North Cascades region of Washington State during the last century. The purpose of this thesis is to determine whether calving associated with the proglacial South Cascade Lake significantly influenced the glacier’s retreat. A simple numerical model using documented and projected historical net mass balances, bed configuration data, and lake basin data is used to approximate the recession of South Cascade Glacier during the last century. To evaluate the influence of …

The European Coal And Steel Community: The Path Towards European Integration, Nicholas Hudson

University Honors Theses

This inquiry seeks to establish the importance of the European Coal and Steel Community (ECSC) and its key role as the foundation for deeper European integration projects, which ultimately have manifested in the European Union seen today. By the end of the Second World War, the European continent was left in ruins, with nations desperately seeking to rebuild their economies and infrastructures, while also attempting to create a stability that would bring lasting peace to a region historically torn apart by war. European leaders, including the French diplomat Jean Monnet, were faced with the challenge of increasing output and employment …

Ribozyme/Duplex Binding Interactions As A Thermodynamic Basis For Chemical Game Theory, Elizabeth Satterwhite

University Honors Theses

Origins of life research requires searching for a plausible transition from simple chemicals to larger macromolecules that can both hold information and catalyze their own production. It has been shown that some classes of RNA molecules possess the ability to help other RNA molecules form by recombination reactions in an auto-catalytic fashion.¹ By simplifying these recombination reactions, the thermodynamic binding strength between two nucleotides of two molecules can be quantified for all 16 possible genotype combinations. The purpose of this research is to provide evidence that the thermodynamic binding strength between the tag and internal guide sequence (IGS) is …

Formation Of Double Ridges On Europa Due To Viscoelastoplastic Deformation Above Crystallizing Cryovolcanic Intrusions, Dougal Hansen

University Honors Theses

Jupiter’s moon Europa is comprised of an icy shell and a ~100 km thick global ocean overlying a rocky core. Among the myriad topographic features etched across its enigmatic surface, double ridges, which consist of two raised flanks with a central trough, are the most pervasive. Often running for hundreds of kilometers, they frequently overprint and offset pre-existing features and appear to be genetically related to cracks in the icy shell. Yet, after nearly two decades of study, these ridge systems and the processes through which they form remain incompletely understood. Several mechanisms have been proposed for ridge formation, one …

A Low-Cost Apparatus For Laboratory Exercises And Classroom Demonstrations Of Geometric Optics, William Vincent Tex Hahn

University Honors Theses

Current trends in research towards the teaching of geometric suggest a constructivist approach. Student experimentation dealing directly with student misconceptions through repetition of examples in many contexts to confront conflicting reasoning allow students to construct definitions with their experiences and observations. Developing the scientific method of observation, prediction/experimental design, conducting experiments and repeating is reinforced with these techniques. Cataloguing student misconceptions and redesigning course material and laboratory experiments in their context has only recently begun. Use of technology has also been shown to increase student interest in course material and 3D printers have recently become common tools in schools. Additionally, …

Characterization Of Photonic Waveguides Using Fourier Analysis, Sam Olson

University Honors Theses

In this work, several characteristics of indium tin oxide (ITO) thin-film waveguides are analyzed. The simulation software COMSOL Multiphysics is used to create two waveguide models, one with a single 400 nm diameter hole, and one with two 400 nm diameter holes. A 410 nm light source is incident upon the models at an angle of 60° from the normal. Fourier analysis performed upon the normalized electric field at the surface led to effective indices in the waveguide of about 1.76 and 2.05.

Pdxscholar Annual Report 2015, Karen Bjork, Sherry Buchanan, David Coate, Bertrand Robinson, Stacey Schlatter

Library Faculty and Staff Publications and Presentations

This report details the fifth year of operation for PDXScholar, Portland State University's institutional repository. The report covers the period between January 1, 2015 and December 31, 2015.

The State Of The Portland Msa Housing Market, Portland State University. Northwest Economic Research Center

Northwest Economic Research Center Publications and Reports

On its surface, the rapid increase of home prices in the Portland Metropolitan Statistical Area (MSA) resembles the overheated moments before the housing bubble burst in 2007. OnPoint Community Credit Union, concerned that history may already be repeating itself, asked the Northwest Economic Research Center (NERC) to investigate speculation within the Portland housing market, provide a forecast of home prices, and summarize potential market headwinds and tailwinds.

To accomplish this, NERC estimates the change in local home prices due to ‘fundamental’ drivers. Using population and income to estimate a fundamental home price index (HPI), this analysis compares the fundamental HPI …

Mangrove Enhancement As A Climate Change Adaptation Strategy In The Republic Of The Marshall Islands (Rmi): Potential Ecosystem Service Shifts Following Colonization, Andrew S. Harwood

Environmental Science and Management Professional Master's Project Reports

The ability of Small Island Developing States (SIDS) and Pacific Island communities to adapt to the increasing sea-levels, storm surge, saltwater intrusion, and other threats posed by global climate change is critical to the survival of many of these local communities as well as their cultures (LivingIslands.org). One of the world’s most striking examples of a nation at great risk is the Republic of the Marshall Islands (RMI) in the central Pacific Ocean. Due to a combination of factors, including the country’s extremely low elevation above sea-level (an average of 2 meters) and lack of adequate structures to provide safety …

Assessment Of Tmdl Implementation And Water Quality Status And Trends In Amazon Creek And Coyote Creek Watersheds, Stosh Zydek

Environmental Science and Management Professional Master's Project Reports

In this project, I analyzed the status and trends of water quality data describing fecal bacteria (E. coli) and DO in the Amazon and Coyote Creek watersheds of the Southern Willamette Valley, Oregon. I also examined TMDL implementation plans produced by DMAs, determined if and how implementation activities corresponded to changes in water quality, compared management and planning of DMAs in the watersheds, discussed aspects of the current TMDL, and compared state regulations and standards in other states. I concluded by making management recommendations to better facilitate future status and trend analysis.

Amazon Creek, Amazon Diversion Channel, A-3 …

Management Plan For Western Painted Turtle (Chrysemys Picta Belli) At Fairview Creek Headwaters, Ashley Smithers

Environmental Science and Management Professional Master's Project Reports

Western painted turtles (Chrysemys picta belli) are found occupying Fairview Creek Headwaters (FCH) in Gresham, Oregon. This urban stream contains a large wetland with an adjacent butte, all managed by the City of Gresham. This management plan addresses the preferred habitat and population of turtles at the site. A habitat delineation of the site revealed specific locations where habitat improvements could take place as well as areas of already beneficial habitat. Two site plans were prepared showing areas of the site that could be enhanced with nesting habitat as well as additional aquatic habitat and basking habitat. A habitat study …

Greenroof Study: Final Report, An Assessment Of Greenroof Design And Maintenance In Portland, Oregon: 2011 – 2013, Windy Carney Beck

Environmental Science and Management Professional Master's Project Reports

In 1999 the City of Portland (City) began to require that stormwater management facilities (SMF) be built when private property is newly developed or redeveloped (City Code Chapter 17.38). Proper maintenance and upkeep of SMFs is essential to ensuring they function appropriately. The City's Maintenance Inspection Program (MIP) is tasked with inspecting stormwater management facilities on private properties in order to ensure that they are being properly operated and maintained and to meet provisions of the City's NPDES Municipal Separated Storm Sewer System (MS4) permit.

Greenroofs are one type of SMF that are installed to satisfy this requirement. Understanding the …

“I Understand What These Students Are Experiencing”: Linguistically Diverse Preservice Teachers’ Narratives Regarding English Learners, Amanda Sugimoto

Curriculum and Instruction Faculty Publications and Presentations

Preservice teachers enter their preparation programs with multiple years of experience in schools as k-12 students. Past schooling experiences, or their ‘apprenticeship of observation’ (Lortie, 1975), often shape preservice teachers’ understandings of schools, teaching, and learning. Teacher preparation programs must address these experiences and related preconceptions when preparing preservice teachers to work with students, specifically diverse student populations (Hammerness et al., 2005). While the majority of the teaching force remains White, female, and monolingual English speaking, the scholarly community has begun to focus on the preparation of diverse preservice teachers (e.g., Tsui, 2007). This study focuses on one such a …

Subreption, Radical Institutionalism, And Evolutionary Economics, John B. Hall, Alexander Dunlap, Joe Mitchell-Nelson

Economics Faculty Publications and Presentations

This inquiry seeks to establish the importance of subreption as an approach to economic and social evolution that also proves integral to the tradition of radical institutionalism. We relate subreption’s etymology and appearances in Roman, Canon and Scots Law, as well as in Philosophy, to its applications found in writings advanced by Thorstein Veblen and carried on later as William Dugger details the rise of corporate hegemony. Understood as an approach derivable from selected philosophical writings of Immanuel Kant, in social science subreption is suggested to occur through the introduction of an outside value that sets off a form of …

Response Of Antarctic Cryoconite Microbial Communities To Light, Elizabeth A. Bagshaw, Jemma L. Wadham, Martyn Tranter, Rupert Perkins, Alistair Morgan, Christopher J. Williamson, Andrew G. Fountain, Sean Fitzsimons, Ashley Dubnick

Geology Faculty Publications and Presentations

Microbial communities on polar glacier surfaces are found dispersed on the ice surface, or concentrated in cryoconite holes and cryolakes, which are accumulations of debris covered by a layer of ice for some or all of the year. The ice lid limits the penetration of photosynthetically available radiation (PAR) to the sediment layer, since the ice attenuates up to 99% of incoming radiation. This suite of field and laboratory experiments demonstrates that PAR is an important control on primary production in cryoconite and cryolake ecosystems. Increased light intensity increased efficiency of primary production in controlled laboratory incubations of debris from …

Looking To The Future Of Education: A Social Art Practice Pedagogy, Alexis Xochihua

University Honors Theses

This article discusses how the implementation of a social practice arts pedagogy will benefit the American educational system. It discusses methodologies and influences that affect the current system and how this system does not prepare students for higher education or life. The social practice art pedagogy utilized arts-integrated pluralization of topics and integration of social examination in order to develop critical thinking skills, social awareness, and quality of education.

Arts Integrated Elementary School Classrooms And Academic Success, Rachel Fackler

University Honors Theses

To support academic achievement, schools must consider an arts integrated approach to lecture based learning. However, teachers, especially those from lower funded schools, who want to integrate the arts into their classrooms often have to fight and defend their reasoning for doing so. With standardized test scores often being the "end all be all" to how schools are funded and supported, arts education has been some of the first variables to be cut from schools and school districts. This is a failure to the students who need a multi-sensory approach to learning that only art can provide. Activities that activate …

Convex And Nonconvex Optimization Techniques For The Constrained Fermat-Torricelli Problem, Nathan Lawrence

University Honors Theses

The Fermat-Torricelli problem asks for a point that minimizes the sum of the distances to three given points in the plane. This problem was introduced by the French mathematician Fermat in the 17th century and was solved by the Italian mathematician and physicist Torricelli. In this thesis we introduce a constrained version of the Fermat-Torricelli problem in high dimensions that involves distances to a finite number of points with both positive and negative weights. Based on the distance penalty method, Nesterov’s smoothing technique, and optimization techniques for minimizing differences of convex functions, we provide effective algorithms to solve the problem. …

A Multivariate Nonlinear Mixed Effects Model For Longitudinal Image Analysis: Application To Amyloid Imaging, Murat Bilgel, Jerry L. Prince, Dean F. Wong, Susan M. Resnick, Bruno M. Jedynak

Mathematics and Statistics Faculty Publications and Presentations

It is important to characterize the temporal trajectories of disease-related biomarkers in order to monitor progression and identify potential points of intervention. These are especially important for neurodegenerative diseases, as therapeutic intervention is most likely to be effective in the preclinical disease stages prior to significant neuronal damage. Neuroimaging allows for the measurement of structural, functional, and metabolic integrity of the brain at the level of voxels, whose volumes are on the order of mm³. These voxelwise measurements provide a rich collection of disease indicators. Longitudinal neuroimaging studies enable the analysis of changes in these voxelwise measures. However, …