Physical Sciences and Mathematics Commons^™

Wave Field Migration As A Tool For Estimating Spatially Continuous Radar Velocity And Water Content In Glaciers, John H. Bradford, Joel T. Harper

Geosciences Faculty Publications

Normal-moveout velocity analysis can lead to significant overestimates of the velocity structure of temperate glaciers since most englacial reflectors approximate point scatters and violate the assumption of planar flat lying reflectors. Migration velocity analysis (MVA) is a tool that does not depend on the assumption of flat lying reflectors. MVA can provide laterally and vertically continuous velocity estimates from conventional common-offset radar sections. In a study of temperate Bench Glacier, Alaska, we used MVA coupled with dielectric modeling to estimate the distribution of water content along a cross-section of the glacier. We found the glacier has two layers, an upper …

Composable Timed Automata Models For Real-Time Embedded Systems Middleware, Venkita Subramonian, Christopher Gill, Cesar Sanchez, Henny Sipma

All Computer Science and Engineering Research

Middleware for distributed real-time embedded (DRE) systems has grown more and more complex in recent years, to address functional and temporal requirements of complex real-time applications. While current approaches for modeling middleware have eased the task of assembling, deploying and configuring middleware and applications, a more formal, fundamental and lower-level set of models is needed to be able to uncover subtle safety and timing errors introduced by interference between computations, particularly in the face of alternative concurrency strategies in the middleware layer. In this paper, we examine how formal models of lower-level middleware building blocks provide an appropriate level of …

Resonant Nucleation, Marcelo Gleiser, Rafael C. Howell

Dartmouth Scholarship

We investigate the role played by fast quenching on the decay of metastable (or false vacuum) states. Instead of the exponentially slow decay rate per unit volume, ΓHN∼exp[−Eb/kBT] (Eb is the free energy of the critical bubble), predicted by homogeneous nucleation theory, we show that under fast enough quenching the decay rate is a power law ΓRN∼[Eb/kBT]−B, where B is weakly sensitive to the temperature. For a range of parameters, large-amplitude oscillations about the metastable state trigger the resonant emergence of coherent subcritical configurations. Decay mechanisms for different Eb are proposed and illustrated in a (2+1)-dimensional scalar field model.

Numerical Solutions Of The Three-Dimensional Magnetohydrodynamic Α Model, Pablo D. Mininni, David C. Montgomery, Annick Pouquet

Dartmouth Scholarship

We present direct numerical simulations and α-model simulations of four familiar three-dimensional magnetohydrodynamic (MHD) turbulence effects: selective decay, dynamic alignment, inverse cascade of magnetic helicity, and the helical dynamo effect. The MHD α model is shown to capture the long-wavelength spectra in all these problems, allowing for a significant reduction of computer time and memory at the same kinetic and magnetic Reynolds numbers. In the helical dynamo, not only does the α model correctly reproduce the growth rate of magnetic energy during the kinematic regime, it also captures the nonlinear saturation level and the late generation of a large scale …

Improving And Extending Behavioral Animation Through Machine Learning, Jonathan J. Dinerstein

Theses and Dissertations

Behavioral animation has become popular for creating virtual characters that are autonomous agents and thus self-animating. This is useful for lessening the workload of human animators, populating virtual environments with interactive agents, etc. Unfortunately, current behavioral animation techniques suffer from three key problems: (1) deliberative behavioral models (i.e., cognitive models) are slow to execute; (2) interactive virtual characters cannot adapt online due to interaction with a human user; (3) programming of behavioral models is a difficult and time-intensive process. This dissertation presents a collection of papers that seek to overcome each of these problems. Specifically, these issues are alleviated …

Adoption Of Riparian Forest Buffers On Private Lands In Nebraska, Usa, Peter Skelton, Scott J. Josiah, James W. King, James R. Brandle, Glenn A. Helmers, Charles A. Francis

Department of Agricultural Leadership, Education, and Communication: Faculty Publications

Pesticide and nutrient runoff from agricultural fields is a socio-environmental problem in the Midwestern United States. Riparian forest buffers (RFBs) are a proven conservation practice that effectively manage this problem, though adoption rates are low. A mail survey was conducted to determine differences between adopter and nonadopter characteristics and attitudes with regard to the use of RFBs. Data were collected from 48 RFB adopters and 261 RFB nonadopters in two Nebraska watersheds. Inferential and multivaririate statistics were used to identify differences between adapter status and producer status groups. About half (50.8%) the respondents were nonproducers. Nonproducers are agricultural landowners not …

Bimetallic Pt-Ag And Pd-Ag Nanoparticles, Frank D. Blum, Akira Tokuhiro, Massimo F. Bertino, Carmen M. Doudna

Chemistry Faculty Research & Creative Works

We report studies of bimetallic nanoparticles with 15%-16% atomic crystal parameters size mismatch. The degree of alloying was probed in a 2-nm Pt core (smallest attainable core size) of Pt-Ag nanoparticles (completely immiscible in bulk) and 20-nm-diameter Pd-Ag nanowires (completely miscible in bulk). Particles were synthesized radiolytically, and depending on the initial parameters, they assume spherical or cylindrical (nanowire) morphologies. In all cases, the metals are seen to follow their bulk alloying characteristics. Pt and Ag segregate in both spherical and wire forms, which indicates that strain due to crystallographic mismatch overcomes the excess surface free energy in the small …

Interactive Image Filling-In, Teryl Lynne Arnold

Theses and Dissertations

Removing unwanted scratches or objects from an image in an undetectable manner is a technique that has been researched for its many useful and varied applications, such as removing scratches, defects, super-imposed text, or even entire objects from a scene. Currently there is a wide variety of algorithms that fill in unwanted regions, none of which incorporate user preferences into the structure completion process. By building a framework to incorporate user preferences into the filling-in process, user input can be utilized to more effectively fill in damaged regions in an image. User input can influence the filling-in process in a …

T-Spline Merging, Heather Ipson

Theses and Dissertations

Geometric models, such as for use in CAD/CAM or animation, are often constructed in a piece-wise fashion. Historically, these models have been made of NURBS surfaces. For various reasons it is problematic and often times mathematically impossible to combine several NURBS models into one continuous surface. The recent invention of a surface type called T-splines has made the combining of NURBS surfaces into a single continuous surface possible, but much of the mathematics has yet to be explored. This thesis explores the mathematics and algorithms necessary to merge multiple NURBS, T-spline, or T-NURCC surfaces into a single continuous surface. This …

Two-Photon Photoionization Of The Ca 4s3d^1d2 Level In An Optical Dipole Trap, E. A. Cummings, J. E. Daily, Dallin S. Durfee, Scott D. Bergeson, R. Gommers

Faculty Publications

We report an optical dipole trap for calcium. The trap is created by focusing a 488-nm argon-ion laser beam into a calcium magneto-optical trap. The argon-ion laser photoionizes atoms in the trap because of a near-resonance with the 4s4f 1^F3 level. By measuring the dipole-trap decay rate as a function of argon-ion laser intensity, we determine the 1^F3 photoionization cross section at our wavelength to be approximately 230 Mb.

Patterns Of Fish Use And Piscivore Abundance Within A Reconnected Saltmarsh Impoundment In The Northern Indian River Lagoon, Florida, Philip W. Stevens, Clay L. Montague, Kenneth J. Sulak

United States Geological Survey: Staff Publications

Nearly all saltmarshes in east-central, Florida were impounded for mosquito control during the 1960s. The majority of these marshes have since been reconnected to the estuary by culverts, providing an opportunity to effectively measure exchange of aquatic organisms. A multi-gear approach was used monthly to simultaneously estimate fish standing stock (cast net), fish exchange with the estuary (culvert traps), and piscivore abundance (gill nets and bird counts) to document patterns of fish use in a reconnected saltmarsh impoundment. Changes in saltmarsh fish abundance, and exchange of fish with the estuary reflected the seasonal pattern of marsh flooding in the northern …

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix: Quaterly Report January-March 2005, Spencer M. Steinberg

Separations Campaign (TRP)

We have continued experiments on the reaction of iodate with sphagnum peat moss. We have established that iodate added to a suspension of peat moss undergoes reduction and to a significant extent is incorporated in to the peat moss. We have confirmed the incorporation of iodine into the peat matrix using pyrolysis GC/MS. In addition, we have performed a scaled up pyrolysis using the preparative GC system that was described in a previous report. This instrument consisted of a packed column gas chromatograph (SRI 8010) with a TCD detector and injector valve equipped with a thermal desorber. Pyrolysis experiments were …

Spatial Variability In Biogenic Gas Accumulations In Peat Soils Is Revealed By Ground Penetrating Radar (Gpr), Xavier Comas, Lee Slater, Andrew S. Reeve

Earth Science Faculty Scholarship

We performed surface and borehole ground penetrating radar (GPR) tests, together with moisture probe measurements and direct gas sampling to detect areas of biogenic gas accumulation in a northern peatland. The main findings are: (1) shadow zones (signal scattering) observed in surface GPR correlate with areas of elevated CH4 and CO2 concentration; (2) high velocities in zero offset profiles and lower water content inferred from moisture probes correlate with surface GPR shadow zones; (3) zero offset profiles depict depth variable gas accumulation from 0-10% by volume; (4) strong reflectors may represent confining layers restricting upward gas migration. Our results have …

The Tirac™ Development Toolkit: Technical Description, Russell Leighton, Lakshmi Vempati, Alan Davis, Mark Porczak, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This report provides a technical description of the Toolkit for Information Representation and Agent Collaboration (TIRAC^™) software framework for the development of intelligent decision-support applications. An overview of the transformational forces that have precipitated the need for a development toolkit capable of supporting a distributed, information-centric software environment, and the objectives of TIRAC™ are contained in a companion CDM Technical Report (CDM-17-04) entitled: “The TIRAC^™ Development Toolkit: Purpose and Overview.”

TIRAC™ is an application development framework and toolkit for distributed decision-support systems incorporating software agents that collaborate with each other and human users to monitor changes (i.e., …

What A Mesh: Dependent Data Types For Correct Mesh Manipulation Algorithms, Joel R. Brandt

All Computer Science and Engineering Research

The Edinburgh Logical Framework (LF) has been proposed as a system for expressing inductively defined sets. I will present an inductive definition of the set of manifold meshes in LF. This definition takes into account the topological characteri-zation of meshes, namely their Euler Characteristic. I will then present a set of dependent data types based on this inductive def-inition. These data types are defined in a programming language based on LF. The language’s type checking guarantees that any typeable expression represents a correct manifold mesh. Furthermore, any mesh can be represented using these data types. Hence, the encoding is sound …

Long-Lived Spin Coherence States In Semiconductor Heterostructures, Yuriy V. Pershin Dr

Faculty Publications

We study evolution of electron spin coherence having nonhomogeneous direction of spin polarization vector in semiconductor heterostructures. It is found that the electron spin relaxation time due to the D’yakonov- Perel’ relaxation mechanism essentially depends on the initial spin polarization distribution. This effect has its origin in the coherent spin precession of electrons diffusing in the same direction. We predict a long spin relaxation time of a novel structure: a spin coherence standing wave and discuss its experimental realization.

Presentation To Mojave-Southern Great Basin Rac, Public Lands Institute

Presentations (PLI)

University manages selected SNPLMA projects as determined by the four federal agencies. Projects must be:

• Compatible with UNLV’s mission.
• Enhance education and research.
• Draw upon expertise of faculty, staff, and students.

Monitoring Relative Abundance Of American Shad In Virginia Rivers 2004 Annual Report, John E. Olney

Reports

Concern about the decline in landings of American shad (Alosa sapidissima) along the Atlantic coast prompted the development of an interstate fisheries management plan (FMP) under the auspices of the Atlantic States Marine Fisheries Management Program (ASMFC 1999). Legislation enables imposition of federal sanctions on fishing in those states that fail to comply with the FMP. To be in compliance, coastal states are required to implement and maintain fishery-dependent and fishery-independent monitoring programs as specified by the FMP. For Virginia, these requirements include spawning stock assessments, the collection of biological data on the spawning run (e.g., age-structure, sex ratio, and …

January: Search Based On Social Insect Behavior, Peter C. Lamborn

Theses and Dissertations

January is a group of interacting stateless model checkers. Each agent functions on a processor located on a super computer or a network of workstations (NOW). The agent's search pattern is a semi-random walk based on the behavior of the grey field slug (Agriolimax reticulatus), the house fly (Musca domestica), and the black ant (Lassius niger). The agents communicate to lessen the amount of duplicate work being done. Every algorithm has a memory threshold above which they search efficiently. This threshold varies not only by model but also by algorithm. Janaury's threshold is lower than the thresholds of other algorithms …

Measurement Of The Tt̅ Production Cross Section In Pp̅ Collisions At √S =1.96 Tev Using Kinematic Fitting Of B-Tagged Lepton+Jet Events, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report a measurement of the tt̅ production cross section using the CDF II detector at the Fermilab Tevatron. The data consist of events with an energetic electron or muon, missing transverse energy, and three or more hadronic jets, at least one of which is identified as a b-quark jet by reconstructing a secondary vertex. The background fraction is determined from a fit of the transverse energy of the leading jet. Using 162±10 pb^-1 of data, the total cross section is found to be 6.0±1.6(stat.)±1.2(syst.) pb, which is consistent with the standard model prediction.

An Estimate Of The Gas Transfer Rate From Oceanic Bubbles Derived From Multibeam Sonar Observations Of A Ship Wake, Thomas C. Weber, Anthony P. Lyons, David L. Bradley

Center for Coastal and Ocean Mapping

Measurements of gas transfer rates from bubbles have been made in the laboratory, but these are difficult to extrapolate to oceanic bubbles where populations of surfactants and particulate matter that inhibit gas transfer are different. Measurements at sea are complicated by unknown bubble creation rates that make it difficult to uniquely identify and observe the evolution of individual bubble clouds. One method that eliminates these difficulties is to measure bubbles in a ship wake where bubble creation at any given location is confined to the duration of the passing ship. This method assumes that the mechanisms slowing the gas dissolution …

E-Mail Spam Filtering Solution For The Western Interstate Commission For Higher Education (Wiche), Jerry Worley

Regis University Student Publications (comprehensive collection)

WICHE staff, consultants and constituents that connect to WICHE's network are provided with internet access and e-mail accounts. In the past, email was not monitored or controlled, other than scanning e-mail attachments for viruses with Norton Antivirus for Exchange Server. This has become a problem for several reasons. Just a few of the reasons are viruses, wasted staff time, inappropriate material stored on the network and inappropriate use of network resources. The WICHE Spam filtering solution includes monitoring and restriction of incoming and outgoing email, email attachment and storage limitations and filtering incoming email for Spam. All internal, incoming and …

Improving Routing Security Using A Decentralized Public Key Distribution Algorithm, Jeremy C. Goold

Theses and Dissertations

Today's society has developed a reliance on networking infrastructures. Health, financial, and many other institutions deploy mission critical and even life critical applications on local networks and the global Internet. The security of this infrastructure has been called into question over the last decade. In particular, the protocols directing traffic through the network have been found to be vulnerable. One such protocol is the Open Shortest Path First (OSPF) protocol. This thesis proposes a security extension to OSPF containing a decentralized certificate authentication scheme (DecentCA) that eliminates the single point of failure/attack present in current OSPF security extensions. An analysis …

Improving Performance Characteristics Of Hyphenated Preconcentrator Gc Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: A "Gold Standard" For Sensor Development, Touradj Solouski

University of Maine Office of Research Administration: Grant Reports

Professor Touradj Solouki of the University of Maine at Orono is supported by the Analytical and Surface Chemistry Program to investigate cryofocusing of analytes in an Electrospray Ionization Fourier Transform Ion Cyclotron Resonance (ESI-FT-ICR) mass spectrometer. To overcome sensitivity problems of FT-ICR, Professor Solouki has added a pre-concentration (PC) gas chromatograph (GC) step to his setup. The goal of this Small Grant for Exploratory Research is to add an additional device: a cryofocuser after the GC. This is predicted to improve the detection limit by two orders of magnitude, and mass resolving power by a factor of 5-10. The PI …

Fire Retardancy Of Polystyrene - Hectorite Nanocomposites, Dongyan Wang, Bok Nam Jang, Shengpei Su, Jinguo Zhang, Xiaoxia Zheng, Grace Chigwada, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

No abstract provided.

Wavelength Control For A Potassium Resonance Lidar, Everett E. A., Vincent B. Wickwar

Posters

An important ground-based way to measure temperatures and winds in the transition region between the upper mesosphere and lower thermosphere (80 to 105 km) is with a resonance-scatter lidar. An alexandrite laser, with a wavelength in the near infrared at 770 nm, is being added to the Atmospheric Lidar Observatory to make this type of observation of potassium. These observations will complement those that have been made for many years with the green Rayleigh-scatter lidar. For these resonance-scatter observations it is necessary to accurately and precisely control the laser wavelength. The intent is to carefully step across the 4 pm …

Development Of An Online Business-To-Business Gift Box Company, Jason R. Lynn

Regis University Student Publications (comprehensive collection)

The Silvered Leaf & Co. project addresses a potential on-line web solution and e-business for marketing, selling and distributing specialized and contemporary theme-based gift baskets featuring products produced and manufactured on the Western Slope of Colorado. Currently, there are many web-based businesses that offer gift baskets with a variety of goods. However, all of the available options duplicate each other in quality, selection of products, and overall appeal. In addition, the web content and solutions on the existing sites are limited and cluttered. Each provides a few features that are appealing but none contain the majority of the important features …

An Introduction To The Use Of Fillers And Nanocomposites In Fire Retardancy, Charles A. Wilkie

Chemistry Faculty Research and Publications

No abstract provided.

High-Temperature Ferromagnetism In Pulsed-Laser Deposited Epitaxial (Zn,Mn)O Thin Films: Effects Of Substrate Temperature, Aswini K. Pradhan, Kai Zhang, S. Mohanty, J.B. Dadson, D. Hunter, Jun Zhang, David J. Sellmyer, U.N. Roy, Y. Cui, A. Burger, S. Mathews, B. Joseph, B.R. Sekhar, B.K. Roul

David Sellmyer Publications

We report on the observation of remarkable room-temperature ferromagnetism in epitaxial (Zn,Mn)O films grown by a pulsed-laser deposition technique using high-density targets. The optimum growth conditions were demonstrated from x-ray measurements, microstructure, Rutherford backscattering, micro-Raman, and magnetic studies. Superior ferromagnetic properties were observed in (Zn,Mn)O films grown at a substrate temperature of 500 °C and with an oxygen partial pressure of 1 mTorr. Ferromagnetism becomes weaker with increasing substrate temperature due to the formation of isolated Mn clusters irrespective of higher crystalline quality of the film.

Causal Inference In Longitudinal Studies With History-Restricted Marginal Structural Models, Romain Neugebauer, Mark J. Van Der Laan, Ira B. Tager

U.C. Berkeley Division of Biostatistics Working Paper Series

Causal Inference based on Marginal Structural Models (MSMs) is particularly attractive to subject-matter investigators because MSM parameters provide explicit representations of causal effects. We introduce History-Restricted Marginal Structural Models (HRMSMs) for longitudinal data for the purpose of defining causal parameters which may often be better suited for Public Health research. This new class of MSMs allows investigators to analyze the causal effect of a treatment on an outcome based on a fixed, shorter and user-specified history of exposure compared to MSMs. By default, the latter represents the treatment causal effect of interest based on a treatment history defined by the …