Physical Sciences and Mathematics Commons^™

A Newton Root-Finding Algorithm For Estimating The Regularization Parameter For Solving Ill-Conditioned Least Squares Problems, Jodi Mead, Rosemary Renaut

Jodi Mead

We discuss the solution of numerically ill-posed overdetermined systems of equations using Tikhonov a-priori-based regularization. When the noise distribution on the measured data is available to appropriately weight the fidelity term, and the regularization is assumed to be weighted by inverse covariance information on the model parameters, the underlying cost functional becomes a random variable that follows a X2 distribution. The regularization parameter can then be found so that the optimal cost functional has this property. Under this premise a scalar Newton root-finding algorithm for obtaining the regularization parameter is presented. The algorithm, which uses the singular value decomposition of …

Memristics: Memristors, Again?, Rudolf Kaehr

Rudolf Kaehr

This collection gives first and short critical reflections on the concepts of memristics, memristors and memristive systems and the history of similar movements with an own focus on a possible interplay between memory and computing functions, at once, at the same place and time, to achieve a new kind of complementarity between computation and memory on a single chip without retarding buffering conditions.

Wright State University Celebration Of Research, Scholarship And Creative Activities 2010 Book Of Abstracts, Wright State University Office Of Undergraduate Research And Stemm Activities

Symposium of Student Research, Scholarship, and Creative Activities Materials

The student abstract booklet is a compilation of abstracts from students' oral and poster presentations at Wright State University's inaugural Celebration of Research, Scholarship and Creative Activities on April 16, 2010.

A Sequence Stratigraphic And Isotopic Study Of Uppermost Pennsylvanian-Lower Permian Carbonate Strata, Orogrande Basin, New Mexico, Jesse Koch

Dissertations & Theses in Earth and Atmospheric Sciences

Determining how the tropics respond to glaciation is important for improving our global understanding of icehouse worlds. The impetus behind this study is to identify the far-field impacts of Gondwanan glaciation during the Early Permian. Impacts including climate and sea-level change should be evident in sensitive carbonate systems, such as the upper Paleozoic paleotropical strata in the Orogrande Basin. A sequence stratigraphic and stable isotopic approach is used to examine the effects of late Paleozoic climate change in the Orogrande Basin during the acme and subsequent demise of the late Paleozoic ice age.

Sequence stratigraphic analysis suggests the occurrence of …

Visual Networking, James Paul

Regis University Student Publications (comprehensive collection)

This research presents a case study of the Regis Academic Research Network (ARNe). It will focus on network bandwidth graphs and the information collected over a six month period of time. The case study will provide comparison of network bandwidth graphs. This case study will be used to theorize what is happening on the ARNE. In addition it will be used for creating hypotheses on what will happen to the network in the future. The research will also include a project. The project is to provide the setup and planning of the installation of open source tool set. This project …

Two-Dimensional Freezing Criteria For Crystallizing Colloidal Monolayers, Ziren Wang, Ahmed M. Alsayed, Arjun G. Yodh, Yilong Han

Department of Physics Papers

Video microscopy was employed to explore crystallization of colloidal monolayers composed of diameter-tunable microgel spheres. Two-dimensional (2D) colloidal liquids were frozen homogenously into polycrystalline solids, and four 2D criteria for freezing were experimentally tested in thermal systems for the first time: the Hansen–Verlet freezing rule, the Löwen–Palberg– Simon dynamical freezing criterion, and two other rules based, respectively, on the split shoulder of the radial distribution function and on the distribution of the shape factor of Voronoi polygons. Importantly, these freezing criteria, usually applied in the context of single crystals, were demonstrated to apply to the formation of polycrystalline solids. At …

Channel Characterization For Wireless Underground Sensor Networks, Agnelo R. Silva

Computer Science and Engineering: Theses, Dissertations, and Student Research

Wireless Underground Sensor Networks (WUSNs) are natural extensions of the established Wireless Sensor Network (WSN) phenomenon and consist of sensors buried underground which communicate through soil. WUSNs have the potential to impact a wide variety of applications including precision agriculture, environmental monitoring, border patrol, and infrastructure monitoring. The main difference between WUSNs and traditional wireless networks is the communication medium. However, a comprehensive wireless underground channel model for WUSNs has not been developed so far. In this thesis, the Soil Subsurface Wireless Communication (SSWC) channel model is developed based on an extensive empirical study in a large agriculture field. The …

Trust In Social And Sensor Networks, Pramod Anantharam, Krishnaprasad Thirunarayan, Cory Andrew Henson, Amit P. Sheth

Kno.e.sis Publications

Trust can be defined as the perception of the trustor about the degree to which the trustee would satisfy an expectation about a transaction constituting risk. Trust plays a pivotal role when the risk in believing incorrect information is high. With Web 2.0 where user generated content and real time interactions dominate, the openness of data contribution may hinder the quality of information we can get.

Network-Centric Angle Only Tracking, Randy Paffenroth, Jason Yosinski, Nick Coult

Randy C. Paffenroth

The coordinated use of multiple distributed sensors by network communication has the potential to substantially improve track state estimates even in the presence of enemy countermeasures. In the modern electronic warfare environment, a network-centric tracking system must function in a variety of jamming scenarios. In some scenarios hostile electronic countermeasures (ECM) will endeavor to deny range and range rate information, leaving friendly sensors to depend on passive angle information for tracking. In these cases the detrimental effects of ECM can be at least partially ameliorated through the use of multiple networked sensors, due to the inability of the ECM to …

Ecological Niche Modeling And Local Knowledge Predict New Populations Of Gymnocladus Assamicus A Critically Endangered Tree Species, Shaily Menon, Baharul I. Choudhury, M. Latif Khan, A. Townsend Peterson

Shaily Menon

Gymnocladus assamicus is a critically endangered tree species endemic to northeastern India. Local inhabitants traditionally used this species for a variety of purposes. However, rapid population declines led to the species being considered extinct, until fieldwork in 2004 to 2007 identified 14 discrete populations of 1 to 7 trees each. To overcome constraints on field surveys imposed by the region’s remoteness and rugged terrain, we targeted areas of further field inventories by estimating the potential distribution of the species. Ecological niche modeling enabled us to identify 26 sites which the model predicted to be highly suitable for the species’ occurrence. …

Trends In Climate Change Education In Nevada's System Of Higher Education, Amy Northrup

Graduate Research Symposium (GCUA) (2010 - 2017)

This poster presents research into how climate change is taught in Nevada's colleges and universities. A completed inventory of the types of courses in different disciplines and at different institutions that relay information about climate change to students is discussed.

Assessing Invasive Plant Species As Threats In Mojave Desert Parks, Sara L. Mcpherson, Donovan J. Craig, Scott R. Abella

Graduate Research Symposium (GCUA) (2010 - 2017)

The invasion and persistence of exotic plant species threatens the natural features that national parks are designed to protect. For example, park managers have witnessed an increase in the frequency, extent and intensity of fires along with a reduction in native species richness and diversity. Many park managers are familiar with a suite of highly invasive plants, but lack a comprehensive and systematic way of prioritizing invasive plant species based on potential threats to the parks’ resources. We have entered into a collaborative project with the National Park Service’s Inventory and Monitoring program to develop an invasive plant early detection …

The Impact Of Academic Faculty On Campus Sustainability Initiatives, Aurali Dade

Graduate Research Symposium (GCUA) (2010 - 2017)

The focus of this poster is the role of academic faculty on campus sustainability initiatives at Institutions of Higher Education (IHEs). The 4,000+ IHEs in the United States train future leaders and have a great deal of influence on the environment and attitude of communities in which they reside. Academic faculty has a sizable impact on governance and significant influence on students. They also may have a major role in campus sustainability initiatives, practices, and policies at IHEs. In order to address whether this is the case, a survey of academic faculty at accredited colleges and universities in the United …

29 Years Of Vegetation Community Change Across Environmental Gradients In A Mojave Desert Mountain Range, Christopher L. Roberts, James S. Holland, Scott R. Abella

Graduate Research Symposium (GCUA) (2010 - 2017)

There is a great deal of uncertainty as to how biological communities respond to changes in land use and climate change, a situation particularly relevant in protected areas such as national parks that were designated to conserve specific biological features. Utilizing extant vegetation data sets with repeatable methodology can provide opportunities for insight into previous vegetation change and provide base line data for long-term monitoring projects useful for modeling vegetation community trajectories. We have relocated and resurveyed 106 sites from a vegetation community study initiated in 1979 in the Newberry Mountains, southern Nevada, within Lake Mead National Recreation Area managed …

Optical Distress Beacon For Use In Space Environments, Howard Chen, Andrew Joseph Giles, Nathaniel Pinckney, Sarah Harris, Andrew Danowitz, Samuel Seth Osofsky

Computer Science and Software Engineering

A beacon system includes emitter devices, driver circuitry configured for controlling the emitter devices, and at least one processor programmed to receive and process one or more inputs and control the driver circuitry to actuate the emitter devices. In an example embodiment, the emitter devices include visible light sources that are oriented to provide omnidirectional visibility for the beacon system. In an example embodiment, components of the beacon system including the emitter devices, driver circuitry and at least one processor are configured such that in a space environment heat generated by the beacon system is dissipated sufficiently well to prevent …

Youth Initiative Hector’S Helpers: Quarterly Progress Report, Period Covering February 11, 2010 – April 15, 2011, Hector's Helpers

Anti-littering Programs

The third quarter has progressed with the Hector’s Helpers program. We took action with hands-on classroom activities and lead three clean-up field trips. Students learned how to protect public lands in Southern Nevada through our anti-litter and desert dumping initiative. West Career Technical Academy students completed various GIS projects and finished the Adopt-A-Block Handbook. The Hector’s Helpers staff also submitted a formal proposal to study pre- and post-program surveys of students participating in the Hector's Helpers program.

Induction Annealing And Subsequent Quenching: Effect On The Thermoelectric Properties Of Boron-Doped Nanographite Ensembles, Ming Xie, Chee Huei Lee, Jiesheng Wang, Yoke Khin Yap, Paola Bruno, Dieter Gruen, Dileep Singh, Jules Routbort

Department of Physics Publications

Boron-doped nanographite ensembles (NGEs) are interesting thermoelectric nanomaterials for high temperature applications. Rapid induction annealing and quenching has been applied to boron-doped NGEs using a relatively low-cost, highly reliable, laboratory built furnace to show that substantial improvements in thermoelectric power factors can be achieved using this methodology. Details of the design and performance of this compact induction furnace as well as results of the thermoelectric measurements will be reported here.

Nanostructured Poly(3,4-Ethylenedioxythiophene)–Metalloporphyrin Films: Improved Catalytic Detection Of Peroxynitrite, Serban Peteu, Pubudu Peiris, Ermias Gebermichael, Mekki Bayachou

Chemistry Faculty Publications

We investigated in this paper the sensing performance of inherently conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), functionalized with hemin (iron protoporphyrin) as an electrocatalytic reporter. The sensing platform is prepared by electrodeposition of a composite film of hemin–PEDOT on a 30-μm diameter carbon fiber electrode (CFE). The polymerized films were characterized by field emission scanning electron microscopy (FESEM), which pointed to nanostructured films with tortuous pores. The electrocatalytic oxidation of peroxynitrite was characterized by cyclic voltammetry as well as other electrochemical methods. The catalytic current is proportional to the analyte's concentration. Optimized hemin–PEDOT modified CFEs were utilized for the first time to …

The Four-Color Theorem And Chromatic Numbers Of Graphs, Sarah E. Cates

Undergraduate Theses and Capstone Projects

We study graph colorings of the form made popular by the four-color theorem. Proved by Appel and Haken in 1976, the Four-Color Theorem states that all planar graphs can be vertex-colored with at most four colors. We consider an alternate way to prove the Four-Color Theorem, introduced by Hadwiger in 1943 and commonly know as Hadwiger’s Conjecture. In addition, we examine the chromatic number of graphs which are not planar. More specifically, we explore adding edges to a planar graph to create a non-planar graph which has the same chromatic number as the planar graph which we started from.

Charge And Spin Ordering In The Mixed-Valence Compound Lufe2O4, A. Brooks Harris, Taner Yildirim

Department of Physics Papers

Landau theory and symmetry considerations lead us to propose an explanation for several seemingly paradoxical behaviors of charge ordering (CO) and spin ordering (SO) in the mixed valence compound LuFe₂O₄. Both SO and CO are highly frustrated. We analyze a lattice gas model of CO within mean-field theory and determine the magnitude of several of the phenomenological interactions. We show that the assumption of a continuous phase transitions at which CO or SO develops implies that both CO and SO are incommensurate. To explain how ferroelectric fluctuations in the charge-disordered phase can be consistent with an …