Physical Sciences and Mathematics Commons^™

Lower Tropospheric Temperature Variability Over The Usa: A Gis Approach, Souleymane Fall, Dev Niyogi, Gilbert L. Rochon

GIS Day

We use the high resolution North American Regional Analysis (NARR) dataset to build for the United States a Temperature Change Index (TCI) based on four contributing variables derived from the layer-averaged temperature and lapse rate of the 1000mb - 700mb layer (near-surface to 3000 meters) for the 1979-2008 period. The analysis uses Geographic Information Systems (GIS) methods to identify distinct regional patterns based on aggregate temperature trends and variability scores. The resulting index allows us to identify and compare regions that experience high (low) temperature trends and variability that are referred to as hot spots (cold spots). The upper Midwest …

Simulations Of The Dipole-Dipole Interaction Between Two Spatially Separated Groups Of Rydberg Atoms, Thomas J. Carroll, Christopher Daniel, Leah Hoover, Timothy Sidie, Michael W. Noel

Physics and Astronomy Faculty Publications

The dipole-dipole interaction among ultracold Rydberg atoms is simulated. We examine a general interaction scheme in which two atoms excited to the x and x states are converted to y and y states via a Förster resonance. The atoms are arranged in two spatially separated groups, each consisting of only one species of atom. We monitor the state mixing by recording the fraction of atoms excited to the y state as the distance between the two groups is varied. With zero detuning a many-body effect that relies on always resonant interactions causes the state mixing to have a finite range. …

Electromagnetic Scattering Solutions For Digital Signal Processing, Jonathan Blackledge

Other resources

Electromagnetic scattering theory is fundamental to understanding the interaction between electromagnetic waves and inhomogeneous dielectric materials. The theory unpins the engineering of electromagnetic imaging systems over a broad range of frequencies, from optics to radio and microwave imaging, for example. Developing accurate scattering models is particularly important in the field of image understanding and the interpretation of electromagnetic signals generated by scattering events. To this end there are a number of approaches that can be taken. For relatively simple geometric configurations, approximation methods are used to develop a transformation from the object plane (where scattering events take place) to the …

Classification, Clustering And Data-Mining Of Biological Data, Thomas Triplet

School of Computing: Dissertations, Theses, and Student Research

The proliferation of biological databases and the easy access enabled by the Internet is having a beneficial impact on biological sciences and transforming the way research is conducted. There are currently over 1,100 molecular biology databases dispersed throughout the Internet. However, very few of them integrate data from multiple sources. To assist in the functional and evolutionary analysis of the abundant number of novel proteins, we introduce the PROFESS (PROtein Function, Evolution, Structure and Sequence) database that integrates data from various biological sources. PROFESS is freely available at http://cse.unl.edu/~profess/. Our database is designed to be versatile and expandable and …

The Spectroscopic Orbit Of Sao 167450, Visual Companion Of Aa Ceti, Francis C. Fekel, Daryl W. Willmarth

Information Systems and Engineering Management Research Publications

We have determined a spectroscopic orbit for SAO 167450, which is the visual secondary of the W UMa-type eclipsing binary AA Cet, and so the system is quadruple. Radial velocities from the coudé feed and 4 m telescopes at Kitt Peak National Observatory produce an orbit with a period of 25.68 days and an eccentricity of 0.50. We classify both the primary and secondary as G0 subgiant/dwarf stars and find that they are somewhat metal rich relative to the Sun. The high lithium abundances of both components argue that the stars are less than 1 Gyr old. If the components …

On The Behaviour Of Marginal And Conditional Akaike Information Criteria In Linear Mixed Models, Sonja Greven, Thomas Kneib

Johns Hopkins University, Dept. of Biostatistics Working Papers

In linear mixed models, model selection frequently includes the selection of random effects. Two versions of the Akaike information criterion (AIC) have been used, based either on the marginal or on the conditional distribution. We show that the marginal AIC is no longer an asymptotically unbiased estimator of the Akaike information, and in fact favours smaller models without random effects. For the conditional AIC, we show that ignoring estimation uncertainty in the random effects covariance matrix, as is common practice, induces a bias that leads to the selection of any random effect not predicted to be exactly zero. We derive …

Presentations Of Rings With Non-Trivial Semidualizing Modules, David A. Jorgensen, Graham J. Leuschke, Sean Sather-Wagstaff

Mathematics - All Scholarship

Let R be a commutative noetherian local ring. A finitely generated R-module C is semidualizing if it is self-orthogonal and satisfies the condition Hom_R(C,C) \cong R. We prove that a Cohen-Macaulay ring R with dualizing module D admits a semidualizing module C satisfying R\ncong C \ncong D if and only if it is a homomorphic image of a Gorenstein ring in which the defining ideal decomposes in a cohomologically independent way. This expands on a well-known result of Foxby, Reiten and Sharp saying that R admits a dualizing module if and only if R is Cohen-Macaulay and a …

Model-Checking Bndc Properties In Cyber-Physical Systems, Ravi Akella, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

In Cyber-physical systems, which are the integrations of computational and physical processes, it is hard to realize certain security properties. Fundamentally, physically observable behavior leads to violations of confidentiality. We focus on analyzing certain non-interference-based security properties to ensure that interactions between the cyber and physical processes preserve confidentiality. a considerable barrier to this analysis is representing the physical system's interactions. in this paper, these physical system properties are encoded into a discrete event system and the combined Cyber-physical system is described using the process algebra SPA. the model checker, CoPS shows BNDC (Bisimulation based Non-Deducibility on Compositions) properties, which …

Ballistic-Ohmic Quantum Hall Plateau Transition In A Graphene P-N Junction, Tony Low

Birck and NCN Publications

Recent quantum Hall experiments conducted on disordered graphene p-n junction provide evidence that the junction resistance could be described by a simple Ohmic sum of the n and p mediums’ resistances. However in the ballistic limit, theory predicts the existence of chirality-dependent quantum Hall plateaus in a p-n junction. We show that two distinctively separate processes are required for this ballistic-Ohmic plateau transition, namely, (i) hole/electron Landau states mixing and (ii) valley isospin dilution of the incident Landau edge state. These conclusions are obtained by a simple scattering theory argument, and confirmed numerically by performing ensembles of quantum magnetotransport calculations …

Dihomotopic Reduction Used In Deadlock Detection, David A. Cape, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

Deadlock detection for concurrent programs has traditionally been accomplished by symbolic methods or by search of a state transition system. We examine an approach that uses geometric semantics involving the topological notion of dihomotopy to partition the state-space into components, after which the reduced state-space is exhaustively searched. Prior work partitioned the state-space inductively, but in this paper, we show that a recursive technique provides greater reduction of the size of the state transition system. as a result, we expect to see more efficient deadlock detection and eventually more efficient verification of some temporal properties for large problems if the …

Measurement Of The Longitudinal Proton Structure Function At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, F. Cindolo, M. Corradi, G. Iacobucci, A. Margotti, R. Nania, A. Polini, S. Antonelli, M. Basile, M. Bindi, L. Cifarelli, A. Contin, S. De Pasquale, G. Sartorelli, A. Zichichi, D. Bartsch, I. Brock, H. Hartmann

Faculty Publications

The reduced cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. From the cross sections, measured double differentially in Bjorken x and the virtuality, Q 2, the proton structure functions F L and F 2 have been extracted in the region 5 × 10 - 4 < x < 0.007 and 20 < Q 2 < 130 GeV 2. © 2009 Elsevier B.V.

Neural Network Control Of A Class Of Nonlinear Discrete Time Systems With Asymptotic Stability Guarantees, Balaje T. Thumati, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a single and multi-layer neural network (NN) controllers are developed for a class of nonlinear discrete time systems. under a mild assumption on the system uncertainties, which include unmodeled dynamics and bounded disturbances, by using novel weight update laws and a robust term, local asymptotic stability of the closed-loop system is guaranteed in contrast with all other NN controllers where a uniform ultimate boundedness is normally shown. Simulation results are presented to show the effectiveness of the controller design. © 2009 AACC.

Neural Network Control Of Quadrotor Uav Formations, Travis Dierks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel framework for leader-follower formation control is developed for the control of multiple quadrotors unmanned aerial vehicles (UAVs) based on spherical coordinates. the control objective for the follower UAV is to track its leader at a desired- separation, angle of incidence, and a bearing by using an auxiliary velocity control. Then, a novel neural network (NN) control law for the dynamical system is introduced to learn the complete dynamics of the UAV including unmodeled dynamics like aerodynamic friction. Additionally, the interconnection dynamic errors between the leader and its followers are explicitly considered, and the stability of …

Preparation And Characterization Of Stable Macroporous Titania Nano-Wells, Hema Santhi Aluri

Theses and Dissertations

Silica based sol-gel thin films have been extensively studied because of their advantages that include optical transparency, high biodegradability and low intrinsic fluorescence. However, one concern with silica based sol-gel derived materials is their long term stability in aqueous solutions. Another concern is their limited porosity. These two concerns limit the application of these materials in catalysis and separations. The main objective of this study is to prepare porous, thin films using titanium alkoxides as precursors and evaluate their long term stability in aqueous solutions. Colloidal crystal templating will be used to introduce macrosized pores into the titania network. The …

Mash-Ups In Abe Models, And The New Epa Waters Web Services, Larry Theller

GIS Day

Documents recent efforts to integrate Purdue's Long-Term Hydrologic Impact Assessment (L-THIA) land use change model with data from Purdue, USEPA, and Michigan State’s Institute of Water Research within Google Maps

The Security Implication Of Multiple Observers In A Distributed System, Derek P. Ditch, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

Confidentiality is an often overlooked, yet crucial point in the security analysis of a system. infrastructures take for granted that confidentiality is maintained through obfuscation by dissemination of information. This dissemination does indeed maintain the confidentiality of the system when only a small portion of the information can be obtained by an outside observer. However, when multiple observers collaboratively make observations, the confidential information can be revealed or even just partially revealed. If a team of attackers on a system can deduce enough information to successfully perform a crippling attack, the system could not be considered secure. This paper will …

Dinosaurian Faunas Of The Cedar Mountain Formation And La-Icp-Ms Detrital Zircon Ages For Three Stratigraphic Sections, Hirotsugu Mori

Theses and Dissertations

The Cedar Mountain Formation contains the most diverse record of Early Cretaceous dinosaurs in the western hemisphere. However, analyses of its faunas have been hindered because 1) most taxa are based on incomplete/fragmentary materials or incomplete descriptions, 2) most sites and some horizons preserve few taxa, and 3) the stratigraphy and geochronology are poorly understood. To help resolve these stratigraphic and correlation problems U-Pb LA-ICP-MS detrital zircon ages were obtained at significant sites and horizons. These dates indicate all sites at or near the base of the formation are no older than 122 to 124 Ma, thus all basal stratigraphic …

User Survey Regarding The Needs Of Network Researchers In Trace-Anonymization Tools, Jihwang Yeo, Keren Tan, David Kotz

Computer Science Technical Reports

To understand the needs of network researchers in an anonymization tool, we conducted a survey on the network researchers. We invited network researchers world-wide to the survey by sending invitation emails to well-known mailing lists whose subscribers may be interested in network research with collecting, sharing and sanitizing network traces.

A Model Based Fault Detection And Accommodation Scheme For Nonlinear Discrete-Time Systems With Asymptotic Stability Guarantee, Balaje T. Thumati, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a fault detection and accommodation (FDA) framework is developed for unknown nonlinear discrete-time systems. the changes in the system dynamics due to the faults are modeled as a nonlinear function of state and input variables while the time profile of the fault is assumed to be exponentially developing. a fault is detected by monitoring the system states and reconstructing the fault dynamics using online approximators. the online approximator output is used first for fault detection and later reconfigured for accommodation. a stable adaptation law in discrete time is developed not only to characterize the faults but also …

R-Factor: A New Parameter To Enhance Location Accuracy In Rssi Based Real-Time Location Systems, Mohammed Rana Basheer, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

The fundamental cause of localization error in an indoor environment is fading and spreading of the radio signals due to scattering, diffraction, and reflection. These effects are predominant in regions where there is no-line-of-sight (NLoS) between the transmitter and the receiver. Efficient algorithms are needed to identify the subset of receivers that provide better localization accuracy. © 2009 IEEE.

Discovery Of A Magnetic Field In The O9 Sub-Giant Star Hd 57682 By The Mimes Collaboration, J. H. Grunhut, G. A. Wade, W. L.F. Marcolino, V. Petit, H. F. Henrichs, David H. Cohen, E. Alecian, D. A. Bohlender, J.-C. Bouret, O. Kochukhov, C. Neiner, N. St. Louis, R. H.D. Townsend

Physics & Astronomy Faculty Works

We report the detection of a strong, organized magnetic field in the O9IV star HD 57682, using spectropolarimetric observations obtained with ESPaDOnS at the 3.6-m Canada-France-Hawaii Telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Programme. From the fitting of our spectra using non-local thermodynamic equilibrium model atmospheres, we determined that HD 57682 is a 17(-9)(+19)M(circle dot) star with a radius of 7.0(-1.8)(+2.4)R(circle dot) and a relatively low mass-loss rate of 1.4(-0.95)(+3.1) x 10(-9) M(circle dot) yr(-1). The photospheric absorption lines are narrow, and we use the Fourier transform technique to infer v sin i = 15 …

Interview With Robert Dozono, Blackfish Gallery, 2009 (Audio), Robert Dozono

All Sustainability History Project Oral Histories

Interview of Robert Dozono by Greg Plath at Blackfish Gallery in Portland, Oregon on November 21st, 2009.

The interview index is available for download.

Preparing Water Users In The Lower Rio Grande For Adjudication Through An Informative Workshop, Leslie R. Kryder

Water Resources Professional Project Reports

The Lower Rio Grande basin in New Mexico is currently undergoing water right adjudication. The adjudication process is important to identify and quantify water uses throughout the Lower Rio Grande. It is intended to facilitate water rights administration by the Office of the State Engineer. Where water users do not understand the purpose and process, they may not participate effectively. Through conversations with irrigators and others familiar with the situation, I explore some of the water users perspectives regarding the adjudication. In general, the water users find the adjudication packets received from the Office of the State Engineer difficult to …

Survival Analysis With Error-Prone Time-Varying Covariates: A Risk Set Calibration Approach, Xiaomei Liao, David M. Zucker, Yi Li, Donna Spiegelman

Harvard University Biostatistics Working Paper Series

No abstract provided.

Is Survival The Only Or Even The Right Outcome For Evaluating Treatments For Out-Of-Hospital Cardiac Arrest? A Proposed Test Based On Both An Intermediate And Ultimate Outcome., Al Hallstrom

UW Biostatistics Working Paper Series

It is generally agreed that the goal of resuscitation is survival with neurological and physiological status similar to that preceding the cardiac arrest. Previously I have argued that the lack of improvement in outcome from resuscitation over the past 3 to 4 decades, as compared to the substantial progress made in treatment of ischemic heart disease, is a consequence of the absence of randomized clinical trials of new interventions and the use of intermediate endpoints such as return of spontaneous circulation or admittance to hospital. Proponents of these intermediate endpoints have argued that those involved in the resuscitation have no …

Accurate Inversion Of High-Resolution Snow Penetrometer Signals For Microstructural And Micromechanical Properties, Hans-Peter Marshall, Jerome B. Johnson

CGISS Publications and Presentations

Measurements of snow using a high-resolution micropenetrometer can be used to discriminate between different snow types; in lower-density snow the signal is sensitive to microstructure, and micromechanical properties can be estimated. Although a physics-based snow penetration theory was first developed almost a decade ago, since that time the majority of studies using snow micropenetrometers have focused on using direct hardness measurements in statistical relationships. We use Monte-Carlo simulations to rigorously test the existing physics-based snow micropenetration theories over a wide range of parameters. These tests revealed four major sources of error in the inversion, which are corrected in this analysis. …

Interview With Kimberly Holmes, 4r Sustainability, 2009 (Audio), Kimberly Holmes

All Sustainability History Project Oral Histories

Interview of Kimberly Holmes by Patrick Fausel in Portland, Oregon on November 20th, 2009.

The interview index is available for download.

Aether Unleashed, Christian Armendariz-Picon, Alberto Diez-Tejedor

Physics - All Scholarship

We follow a low-energy effective theory approach to identify the general class of theories that describes a vector field (of unconstrained norm) coupled to gravity. The resulting set may be regarded as a generalization of the conventional vector-tensor theories, and as a high-momentum completion of aether models. We study the conditions that a viable cosmology, Newtonian limit and absence of classical and quantum instabilities impose on the parameters of our class of models, and compare these constraints with those derived in previously studied and related cases. The most stringent conditions arise from the quantum stability of the theory, which allows …

Hokua – A Wavelet Method For Audio Fingerprinting, Steven S. Lutz

Theses and Dissertations

In recent years, multimedia identification has become important as the volume of digital media has dramatically increased. With music files, one method of identification is audio fingerprinting. The underlying method for most algorithms is the Fourier transform. However, due to a lack of temporal resolution, these algorithms rely on the short-time Fourier transform. We propose an audio fingerprinting algorithm that uses a wavelet transform, which has good temporal resolution. In this thesis, we examine the basics of certain topics that are needed in understanding audio fingerprinting techniques. We also look at a brief history of work done in this field. …

An Empirical Study Of Instance Hardness, Michael Reed Smith

Theses and Dissertations

Most widely accepted measures of performance for learning algorithms, such as accuracy and area under the ROC curve, provide information about behavior at the data set level. They say nothing about which instances are misclassified, whether two learning algorithms with the same classification accuracy on a data set misclassify the same instances, or whether there are instances misclassified by all learning algorithms. These questions about behavior at the instance level motivate our empirical analysis of instance hardness, a measure of expected classification accuracy for an instance. We analyze the classification of 57 data sets using 9 learning algorithms. Of …