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Articles 1321 - 1350 of 3798

Full-Text Articles in Physical Sciences and Mathematics

Advancing Rationality With Sustainability: An Analysis Of Agent-Based Simulation, Osman Goktug Tanrikulu Jun 2017

Advancing Rationality With Sustainability: An Analysis Of Agent-Based Simulation, Osman Goktug Tanrikulu

Hatfield Graduate Journal of Public Affairs

Today, falling trends of species and ecosystem in the world due to overconsumption and destruction of natural resources are at critical levels. It is vital for humanity to operate with sustainable and resilient modes of production and consumption. In this regard, this paper examines the basic premise of rationality and introduces sustainability as an advancement to the theoretical concept of rationality. Thus, a rational mindset and a sustainable mindset are compared under depletion of environmental resources. The understanding of rationality in the analysis is based on Garett Hardin’s (1968) ‘the tragedy of the commons’ model, in which actors are self-interested …


Fully Generic Programming Over Closed Universes Of Inductive-Recursive Types, Larry Diehl Jun 2017

Fully Generic Programming Over Closed Universes Of Inductive-Recursive Types, Larry Diehl

Dissertations and Theses

Dependently typed programming languages allow the type system to express arbitrary propositions of intuitionistic logic, thanks to the Curry-Howard isomorphism. Taking full advantage of this type system requires defining more types than usual, in order to encode logical correctness criteria into the definitions of datatypes. While an abundance of specialized types helps ensure correctness, it comes at the cost of needing to redefine common functions for each specialized type. This dissertation makes an effort to attack the problem of code reuse in dependently typed languages. Our solution is to write generic functions, which can be applied to any datatype.

Such …


Using Critical Physical Geography To Map The Unintended Consequences Of Conservation Management Programs, Melanie Malone Jun 2017

Using Critical Physical Geography To Map The Unintended Consequences Of Conservation Management Programs, Melanie Malone

Dissertations and Theses

A variety of conservation trends have gained and lost favor throughout the years in agriculture, with U.S. Farm Bills often influencing what conservation practices are implemented by farming communities throughout the U.S. This dissertation focuses on the unintended consequences of conservation management practices in the Fifteenmile Watershed of Wasco County, Oregon. Specifically, I seek to address how farmer enrollment in various conservation techniques, loosely defined as no-till agriculture, has affected soil and water quality through the increased use of herbicide, and subsequently rendered ecological and human health vulnerable. Using a critical physical geography framework, I address both the biophysical factors …


Investigation Of Ambient Reactive Nitrogen Emissions Sources And Deposition In The Columbia River Gorge National Scenic Area, Jacinda L. Mainord Jun 2017

Investigation Of Ambient Reactive Nitrogen Emissions Sources And Deposition In The Columbia River Gorge National Scenic Area, Jacinda L. Mainord

Dissertations and Theses

Anthropogenic reactive nitrogen is emitted into the atmosphere from fossil fuel combustion (nitrogen oxides) and agricultural activities (nitrogen oxides and ammonia). Nitrogen oxide emissions have long been controlled for their role in ambient air pollution and human health effects. However, reactive nitrogen deposition is less understood even though it can play a significant role in altering biodiversity, impairing ecosystem and biogeochemical function and degrading cultural artifacts. Although nitrogen deposition is a natural part of biogeochemical cycling, many ecosystems across the United States are at risk of exceeding the critical nitrogen deposition load. While nitrogen oxides are routinely measured in urban …


Design And Application Of A 3d Photocatalyst Material For Water Purification, Simon Paul Fowler Jun 2017

Design And Application Of A 3d Photocatalyst Material For Water Purification, Simon Paul Fowler

Dissertations and Theses

This dissertation presents a method for enhancement of the efficiency and scalability of photocatalytic water purification systems, along with an experimental validation of the concept. A 3-dimensional photocatalyst structure, made from a TiO2-SiO2 composite, has been designed and fabricated for use in a custom designed LED-source illumination chamber of rotational symmetry that corresponds with the symmetry of the photocatalyst material. The design of the photocatalyst material has two defining characteristics: geometrical form and material composition. The design of the material was developed through the creation of a theoretical model for consideration of the system's photonic efficiency. Fabrication …


Forest Collaborative Meeting Agenda, Athens, Greece, Environment For Development (Efd) Initiative Jun 2017

Forest Collaborative Meeting Agenda, Athens, Greece, Environment For Development (Efd) Initiative

Forest Collaborative Research

Agenda for the 1st Forest Collaborative Workshop on 27 – 28 June 2017 at Athinais Hotel in Athens, Greece Leontius Hall.


Mapping Meaningful Places On Washington’S Olympic Peninsula: Toward A Deeper Understanding Of Landscape Values, Lee Cerveny, Kelly Biedenweg, Rebecca J. Mclain Jun 2017

Mapping Meaningful Places On Washington’S Olympic Peninsula: Toward A Deeper Understanding Of Landscape Values, Lee Cerveny, Kelly Biedenweg, Rebecca J. Mclain

Institute for Sustainable Solutions Publications and Presentations

Landscape values mapping has been widely employed as a form of public participation GIS (PPGIS) in natural resource planning and decision-making to capture the complex array of values, uses, and interactions between people and landscapes. A landscape values typology has been commonly employed in the mapping of social and environmental values in a variety of management settings and scales. We explore how people attribute meanings and assign values to special places on the Olympic Peninsula (Washington, USA) using both a landscape values typology and qualitative responses about residents’ placerelationships. Using geographically referenced social values data collected in community meetings (n …


Sensitivity Of Conus Summer Rainfall To The Selection Of Cumulus Parameterization Schemes In Nu-Wrf Seasonal Simulations, Takamichi Iguchi, Wei-Kuo Tao, Di Wu, Christa D. Peters-Lidard, Joseph A. Santanello, Eric Kemp, Yudong Tian, Jonathan Case, Weile Wang, Robert Ferraro, Duane E. Waliser, Jinwon Kim, Huikyo Lee, Bin Guan, Baijun Tian, Paul C. Loikith Jun 2017

Sensitivity Of Conus Summer Rainfall To The Selection Of Cumulus Parameterization Schemes In Nu-Wrf Seasonal Simulations, Takamichi Iguchi, Wei-Kuo Tao, Di Wu, Christa D. Peters-Lidard, Joseph A. Santanello, Eric Kemp, Yudong Tian, Jonathan Case, Weile Wang, Robert Ferraro, Duane E. Waliser, Jinwon Kim, Huikyo Lee, Bin Guan, Baijun Tian, Paul C. Loikith

Geography Faculty Publications and Presentations

This study investigates the sensitivity of daily rainfall rates in regional seasonal simulations over the contiguous United States (CONUS) to different cumulus parameterization schemes. Daily rainfall fields were simulated at 24-km resolution using the NASA-Unified Weather Research and Forecasting (NU-WRF) Model for June–August 2000. Four cumulus parameterization schemes and two options for shallow cumulus components in a specific scheme were tested. The spread in the domain-mean rainfall rates across the parameterization schemes was generally consistent between the entire CONUS and most subregions. The selection of the shallow cumulus component in a specific scheme had more impact than that of the …


Subgradients Of Minimal Time Functions Without Calmness, Nguyen Mau Nam, Dang Van Cuong Jun 2017

Subgradients Of Minimal Time Functions Without Calmness, Nguyen Mau Nam, Dang Van Cuong

Mathematics and Statistics Faculty Publications and Presentations

In recent years there has been great interest in variational analysis of a class of nonsmooth functions called the minimal time function. In this paper we continue this line of research by providing new results on generalized differentiation of this class of functions, relaxing assumptions imposed on the functions and sets involved for the results. In particular, we focus on the singular subdifferential and the limiting subdifferential of this class of functions.


Wicked Water Problems: Can Network Governance Deliver? Integrated Water Management Case Studies From New Zealand And Oregon, Usa, Jacqueline Dingfelder Jun 2017

Wicked Water Problems: Can Network Governance Deliver? Integrated Water Management Case Studies From New Zealand And Oregon, Usa, Jacqueline Dingfelder

Dissertations and Theses

Integrated water management is a wicked public policy problem with no clear path to resolution. This dissertation is an in-depth qualitative comparative analysis of two collaborative governance processes created to tackle complex water problems in New Zealand and Oregon, U.S.A. Both cases convened a wide range of state and non-state actors in efforts to find common ground, build consensus for change, and develop innovative water policy solutions.

The goal of this comparative case study analysis is to gain a better understanding of collaborative network governance frameworks as applied to integrated water management and primary factors for success. The proposition posits …


Generalized Differential Calculus And Applications To Optimization, R. Blake Rector Jun 2017

Generalized Differential Calculus And Applications To Optimization, R. Blake Rector

Dissertations and Theses

This thesis contains contributions in three areas: the theory of generalized calculus, numerical algorithms for operations research, and applications of optimization to problems in modern electric power systems. A geometric approach is used to advance the theory and tools used for studying generalized notions of derivatives for nonsmooth functions. These advances specifically pertain to methods for calculating subdifferentials and to expanding our understanding of a certain notion of derivative of set-valued maps, called the coderivative, in infinite dimensions. A strong understanding of the subdifferential is essential for numerical optimization algorithms, which are developed and applied to nonsmooth problems in operations …


Cascadia Subduction Tremor Muted By Crustal Faults, Ray E. Wells, Richard J. Blakely, Aaron G. Wech, Patricia A. Mccrory, Andrew Michael Jun 2017

Cascadia Subduction Tremor Muted By Crustal Faults, Ray E. Wells, Richard J. Blakely, Aaron G. Wech, Patricia A. Mccrory, Andrew Michael

Geology Faculty Publications and Presentations

Deep, episodic slow slip on the Cascadia subduction megathrust of western North America is accompanied by low-frequency tremor in a zone of high fluid pressure between 30 and 40 km depth. Tremor density (tremor epicenters per square kilometer) varies along strike, and lower tremor density statistically correlates with upper plate faults that accommodate northward motion and rotation of forearc blocks. Upper plate earthquakes occur to 35 km depth beneath the faults. We suggest that the faults extend to the overpressured megathrust, where they provide fracture pathways for fluid escape into the upper plate. This locally reduces megathrust fluid pressure and …


Utilization Of Remote Sensing In Drought Monitoring Over Iraq, Yousif Almamalachy May 2017

Utilization Of Remote Sensing In Drought Monitoring Over Iraq, Yousif Almamalachy

Dissertations and Theses

Agricultural drought is a creeping disaster that overshadows the vegetative cover in general and cropland specifically in Iraq, a country that was well known for its agricultural production and fertile soil. In the recent years, the arable lands in Iraq experienced increasing land degradation that led to desertification, economic losses, food insecurity, and deteriorating environment. Remote sensing is employed in this study and four different indices are utilized, each of which is derived from MODIS satellite mission products. Agricultural drought maps are produced from 2003 to 2015 after masking the vegetation cover. Year 2008 was found the most severe drought …


Communicating At Terahertz Frequencies, Farnoosh Moshirfatemi May 2017

Communicating At Terahertz Frequencies, Farnoosh Moshirfatemi

Dissertations and Theses

The number of users who get access to wireless links is increasing each day and many new applications require very high data rates. The increasing demand for higher data rates has led to the development of new techniques to increase spectrum efficiency to achieve this goal. However, the limited bandwidth of the frequency bands that are currently used for wireless communication bounds the maximum data rate possible.

In the past few years, researchers have developed new devices that work as Terahertz (THz) transmitters and receivers. The development of these devices and the large available bandwidth of the THz band is …


Influence Of Mixing And Buoyancy On Competition Between Cyanobacteria Species In Upper Klamath Lake, Roberta Joann Brunkalla May 2017

Influence Of Mixing And Buoyancy On Competition Between Cyanobacteria Species In Upper Klamath Lake, Roberta Joann Brunkalla

Dissertations and Theses

Cyanobacterial blooms in lakes impact human health, the economy, and ecosystem health. It is predicted that climate change will promote and increase the frequency and intensity of cyanobacterial blooms due to unique physiological adaptions that allow cyanobacteria to exploit warm stable water bodies. Key cyanobacteria physiological adaptions include nitrogen fixation, buoyancy regulation and higher optimum growth temperatures. The largest uncertainty of predicting the effect of climate change is in understanding how the interactions among species will change. Adding to the ambiguity, cyanobacteria physiological adaptions can vary based on lakespecific ecotypes and can have different sensitivities to temperature. It is critical …


Would You Like Fires With That? Using Stakeholder-Derived Forest Management Preference Maps To Model Landscape-Level Fuel Reduction Treatment Effects On Wildfire Spread, Brooke A. Cassell, Robert M. Scheller, Max Nielsen-Pincus May 2017

Would You Like Fires With That? Using Stakeholder-Derived Forest Management Preference Maps To Model Landscape-Level Fuel Reduction Treatment Effects On Wildfire Spread, Brooke A. Cassell, Robert M. Scheller, Max Nielsen-Pincus

ESM Colloquium

Management of public lands in the U.S. aims to achieve multiple goals relating to ecological function, wildlife habitat, support of local economies, and recreation; and in fire-prone landscapes these goals are often combined with fuels reduction treatments such as forest thinning and prescribed fire. Applied landscape research may attempt to evaluate the tradeoffs implicit in public lands planning or envision potential future land management scenarios, but often fails to incorporate the spatial diversity of stakeholder perspectives. This study explores the use of public participation geographic systems (PPGIS) to identify spatial and thematic community preferences for fuel treatments in a fire-prone …


Non-Native Mangroves Of Moloka’I, Hawai’I: A Socio-Ecological Analysis, Casey Lewis May 2017

Non-Native Mangroves Of Moloka’I, Hawai’I: A Socio-Ecological Analysis, Casey Lewis

ESM Colloquium

Invasive species are recognized as a leading threat to biodiversity and their management is expensive, time consuming, and labor intensive. Therefore, it is important to review both benefits and detriments of the species to inform appropriate management decisions. Red mangrove was introduced to Moloka'i, Hawaii in 1902 to mitigate the effects of soil erosion and has since spread along the coast and to adjacent islands creating novel habitat. This study assessed both biological services and social attitudes towards Moloka'i's non-native mangroves to provide a comprehensive evaluation of the species. Zooplankton community structure was examined in mangrove and non-mangrove sites and …


Modeling The Effectiveness Of Riparian Restoration On Stream Shading In The Clackamas River Basin, Rachel Barksdale May 2017

Modeling The Effectiveness Of Riparian Restoration On Stream Shading In The Clackamas River Basin, Rachel Barksdale

ESM Colloquium

Rivers and streams within the Clackamas River Basin are not currently meeting water quality standards in terms of temperature. The Clackamas River Basin Council (CRBC) designed a restoration program to address the thermal loading on behalf of Portland General Electric (PGE) in which native trees and shrubs are planted along streams to restore riparian canopy cover. Solar radiation can be blocked by restoring canopy cover and is an effective way to provide shade, as well as providing ancillary environmental benefits such as enhanced wildlife habitat and erosion control. Stream and vegetation data were collected at nine sites to model the …


Effects Of Beaver Dams On Surface Water Flow During Storm Events In An Urban Landscape, Erin Poor May 2017

Effects Of Beaver Dams On Surface Water Flow During Storm Events In An Urban Landscape, Erin Poor

ESM Colloquium

Urban land-use generally alters the hydrologic cycle, leading to changes in the natural flow regime of local streams. Runoff from impervious surfaces and routing of stormwater to streams causes urban streams to respond quickly and more intensely to storm events-more so than then would be observed in a less urbanized landscape. The rapid pulse of water that is routed to streams during precipitation events can degrade the physical structure of the channel and alter water quality and habitat availability. To manage these common urban stream issues, agencies have been seeking alternative ways of restoring and enhancing resilience in urban stream …


Long-Term Ecological Research In Forest Park: Tracking Urban Impacts To Forest Structure And Productivity, Andrew Addessi, Marion Dresner May 2017

Long-Term Ecological Research In Forest Park: Tracking Urban Impacts To Forest Structure And Productivity, Andrew Addessi, Marion Dresner

ESM Colloquium

Current and historic land use practices as well as exposure to an urban environment can impact forest structure and function. Past and ongoing research in Forest Park, a large urban forest in Portland, Oregon, suggests that mature Douglas-fir (Psuedotsuga meziesii) dominated conifer stands in the more urban end of the park are not developing certain late successional features. Notably, they lack a shade-tolerant conifer understory composed of western hemlock (Tsuga heterophylla) and western red-cedar (Thuja plicata). Here, I present three lines of investigation taken from several 1-hectare permanent long-term ecological research (LTER) plots in Forest Park. First, I investigated whether …


Community Science And The Ecological Merits Of Backyard Habitat Patches And Adjacent Green-Spaces For Urban Avian Species, Kristen S. Gulick, Nikkie West, Marion Dresner May 2017

Community Science And The Ecological Merits Of Backyard Habitat Patches And Adjacent Green-Spaces For Urban Avian Species, Kristen S. Gulick, Nikkie West, Marion Dresner

ESM Colloquium

In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project investigates the contribution that a group of backyards, certified through the Backyard Habitat Certification Program, have in the suburb of Hillsdale, Oregon, which is adjacent to the natural area of Keller Woodland. Backyard owners functioning as citizen or community scientists assisted with conducting residential bird point-counts once a week in each backyard and the natural area. Counts were done for a total of 8 weeks during nesting season to …


The Limitation Of Spread Of Non-Native Marine Invertebrates From Artificial Structures To Natural Habitats, Whitney Mcclees, Catherine E. De Rivera May 2017

The Limitation Of Spread Of Non-Native Marine Invertebrates From Artificial Structures To Natural Habitats, Whitney Mcclees, Catherine E. De Rivera

ESM Colloquium

Artificial structures created for aquatic anthropogenic activities are often colonized and fouled by many non-native species, few of which have invaded natural areas. Some research has indicated predation is limiting the spread of non-native species, while other research has indicated that it is dispersal-driven. To determine the effects of dispersal limitation and predation on the risk to surrounding habitats of being invaded by non-native species established on marina docks, we used a three-factor design, deploying seven unglazed ceramic panels per each treatment combination of 1) inside versus outside a marina in Yaquina Bay, Oregon; 2) cage keeping out predators >mesh …


Informing Oregon's Marine Protected Area (Mpa) Baseline: Past And Present Tribal Uses Of Marine Resources, Sabra Marie Tallchief Comet May 2017

Informing Oregon's Marine Protected Area (Mpa) Baseline: Past And Present Tribal Uses Of Marine Resources, Sabra Marie Tallchief Comet

ESM Colloquium

Native American tribes with ancestral land adjacent to the coast have gathered, hunted, and fished marine resources for millennia. In 2012, the state of Oregon designated five marine sites as reserves in which ocean development and harvest were prohibited. Marine Protected Areas (MPAs) are paired with each of the reserves and have less stringent “take” restrictions. Conflict over tribal use of MPAs have arisen in other states (e.g., California) as designation of MPAs and Reserves can impact subsistence, ceremonial, and traditional uses. My master’s thesis is intended to inform Oregon MPA management by developing a dataset that will describe tribal …


Bayesian Optimization For Refining Object Proposals, With An Application To Pedestrian Detection, Anthony D. Rhodes May 2017

Bayesian Optimization For Refining Object Proposals, With An Application To Pedestrian Detection, Anthony D. Rhodes

Student Research Symposium

We devise an algorithm using a Bayesian optimization framework in conjunction with contextual visual data for the efficient localization of objects in still images. Recent research has demonstrated substantial progress in object localization and related tasks for computer vision. However, many current state-of-the-art object localization procedures still suffer from inaccuracy and inefficiency, in addition to failing to successfully leverage contextual data. We address these issues with the current research.

Our method encompasses an active search procedure that uses contextual data to generate initial bounding-box proposals for a target object. We train a convolutional neural network to approximate an offset distance …


An Operational Drought Prediction Framework With Application Of Vine Copula Functions, Mahkameh Zarekarizi May 2017

An Operational Drought Prediction Framework With Application Of Vine Copula Functions, Mahkameh Zarekarizi

Student Research Symposium

Early and accurate drought predictions can benefit water resources and emergency managers by enhancing drought preparedness. Soil moisture memory is shown to contain helpful information for prediction of future values. This study uses the soil moisture memory to predict their future states via multivariate statistical modeling. We present a drought forecasting framework which issues monthly and seasonal drought forecasts. This framework estimates droughts with different lead times and updates the forecasts when more data become available. Forecasts are generated by conditioning future soil moisture values on antecedent drought status. The statistical model is initialized by soil moisture simulations retrieved from …


Find, Build, And Export Information For 3d Printing Of Your Favorite Molecules And Crystal Structures At Two Dedicated Websites, Paul R. Destefano, Peter Moeck May 2017

Find, Build, And Export Information For 3d Printing Of Your Favorite Molecules And Crystal Structures At Two Dedicated Websites, Paul R. Destefano, Peter Moeck

Student Research Symposium

As 3D printers require instructions, the Nano-Crystallography Group at Portland State University is creating two websites (http://nanocrystallography.org/3dconvert/ and http://nanocrystallography.research.pdx.edu/3d-print-files/convert/) where such instructions are created, interactively, for the atomic arrangements of virtually all known molecules and crystals.

We will prepare a "pipeline" into which crystallographic information enters from two curated open access crystallographic databases, is manipulated to create the desired 3D models, and then is exported in either STL format (the standard for monochrome 3D printing) or VRML/X3D (the ISO successor to STL). The two aforementioned databases are the North-American mirror of the Crystallography Open Database (http://nanocrystallography.org) …


Quasi-Optical Measurement For Low Loss Material Characterization In Submillimeter Wave Range, Ha Khiem Tran, Thanh Ngoc Dan Le, Branimir Pejcinovic May 2017

Quasi-Optical Measurement For Low Loss Material Characterization In Submillimeter Wave Range, Ha Khiem Tran, Thanh Ngoc Dan Le, Branimir Pejcinovic

Student Research Symposium

An accurate knowledge of dielectric constant of materials is required in many sub-millimeter wave applications. Free-space measurement of materials has always been one of the first choices due to their non-destructive nature and relatively simple sample preparation. However, free-space measurement systems at sub-millimeter frequency range suffer from two main problems: high loss because of divergent beam pattern and diffraction when the beam waist of the radiated beam is relatively large compared to the size of the sample under tests. In order to mitigate these issues, we set up a quasi-optical system using off-axis parabolic mirrors, which enhance the dynamic range …


Non-Native Mangroves Of Moloka'i, Hawai'i: A Socio-Ecological Analysis, Casey Lewis May 2017

Non-Native Mangroves Of Moloka'i, Hawai'i: A Socio-Ecological Analysis, Casey Lewis

Student Research Symposium

Invasive species are recognized as a leading threat to ecosystems and their management is expensive, time consuming, and labor intensive. Therefore, it is important to review both benefits and detriments of the species to inform appropriate management decisions. Red mangrove was introduced to Moloka'i, Hawaii in 1902 to mitigate the effects of soil erosion and has since spread along the coast and to adjacent islands creating novel habitat. This study assessed both biological services and social attitudes towards Moloka'i's non-native mangroves to provide a comprehensive evaluation of the species. Zooplankton community structure was examined in mangrove and non-mangrove sites and …


Cox Processes For Visual Object Counting, Yongming Ma May 2017

Cox Processes For Visual Object Counting, Yongming Ma

Student Research Symposium

We present a model that utilizes Cox processes and CNN classifiers in order to count the number of instances of an object in an image. Poisson processes are well suited to events that occur randomly in space, like the location of objects in an image, as well as to the task of counting. Mixed Poisson processes also offer increased flexibility, however they do not easily scale with image size: they typically require O(n3) computation time and O(n2) storage, where n is the number of pixels. To mitigate this problem, we employ Kronecker algebra which takes advantage of the direct product …


The Importance Of Urban Habitat Connectivity And Influence On Native Avian Species And Community Science, Kristen S. Gulick May 2017

The Importance Of Urban Habitat Connectivity And Influence On Native Avian Species And Community Science, Kristen S. Gulick

Student Research Symposium

In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project investigates the contribution that a group of backyards, certified through the Backyard Habitat Certification Program, have in the suburb of Hillsdale, Oregon, which is adjacent to the natural area of Keller Woodland. Backyard owners functioning as citizen or community scientists assisted with conducting residential bird point-counts once a week in each backyard and the natural area. Counts were done for a total of 8 weeks during nesting season to …