Physical Sciences and Mathematics Commons^™

Measuring Multiple Parameters In A Self-Mixing Optical Feedback System, Yanguang Yu, Jiangtao Xi, Enbang Li, Joe F. Chicharo, Thierry Bosch

Faculty of Informatics - Papers (Archive)

We propose a new approach that yields the values of multiple parameters at the same time for self-mixing optical feedback interferometric systems. These parameters are the linewidth enhancement factor of Semiconductor Lasers, the optical feedback level factor as well as vibration information of a target including the frequency and the amplitude. The method is based on optical feedback interferometry. Its effectiveness has been confirmed by computer simulations and experiments.

Robust And Distributed Computation Of Aggregates In Wireless Sensor Networks, Jen-Yeu Chen, Gopal Pandurangan, Dongyan Xu

Department of Computer Science Technical Reports

No abstract provided.

Unstructured Peer-To-Peer Networks For Sharing Processor Cycles, Asad Awan, Ronaldo A. Ferreira, Suresh Jagannathan, Ananth Y. Grama

Department of Computer Science Technical Reports

No abstract provided.

Weighted Canonical Forms Of Nonlinear Single-Input Control Systems With Noncontrollable Linearization, Issa Amadou Tall, Witold Respondek

Miscellaneous (presentations, translations, interviews, etc)

We propose a weighted canonical form for single-input systems with noncontrollable first order approximation under the action of formal feedback transformations. This weighted canonical form is based on associating different weights to the linearly controllable and linearly noncontrollable parts of the system. We prove that two systems are formally feedback equivalent if and only if their weighted canonical forms coincide up to a diffeomorphism whose restriction to the linearly controllable part is identity.

Statistical Tools For Digital Image Forensics, Alin C. Popescu

Dartmouth College Ph.D Dissertations

A digitally altered image, often leaving no visual clues of having been tampered with, can be indistinguishable from an authentic image. The tampering, however, may disturb some underlying statistical properties of the image. Under this assumption, we propose five techniques that quantify and detect statistical perturbations found in different forms of tampered images: (1) re-sampled images (e.g., scaled or rotated); (2) manipulated color filter array interpolated images; (3) double JPEG compressed images; (4) images with duplicated regions; and (5) images with inconsistent noise patterns. These techniques work in the absence of any embedded watermarks or signatures. For each technique we …

A Calibration Approach For Decoupling Colour Cross-Talk Using Nonlinear Blind Signal Separation Network, Y. Hu, Jiangtao Xi, Enbang Li, Joe F. Chicharo, Zongkai Yang, Yuanguang Yu

Faculty of Informatics - Papers (Archive)

We present a calibration approach to invert the nonlinear mixing process of colour cross-talk in multi-channel profilometry systems. Parameters of the inverse network are determined by a nonlinear blind signal separation algorithm. Experimental and simulation results demonstrate that proposed approach can effectively reduce colour leakages and improve the measurement accuracy.

A Credit-Based Distributed Protocol For Long-Term Fairness In Ieee 802.11 Single-Hop Networks, Yan Wu, Sonia Fahmy

Department of Computer Science Technical Reports

No abstract provided.

Multiple Ionization Of Ne By H2⁺ Ions With Correlated Projectile Electron Loss, M. M. Sant'anna, H. Luna, Antonio C. Santos, C. Mcgrath, M. B. Shah, E. G. Cavalcanti, G. M. Sigaud, E. C. Montenegro

Physics Faculty Research & Creative Works

We consider multiple ionization of Ne by fast H²⁺, with and without projectile electron loss. Measurements of the total cross section for the direct ionization channel support the similarity of ionization of Ne by an H²⁺ projectile that does not break and Ne ionization by an equi-velocity proton. the multiple target ionization with projectile electron loss is analyzed within a proposed model, adapted from the independent particle model, taking into account post-collisional decay channels following the ionization of Ne 2s electrons. We point out that, for the H²⁺ + Ne collision system, the post-collisional decay channels …

Relativistic And Radiative Corrections To The Mollow Spectrum, Jorg Evers, Ulrich D. Jentschura, Christoph H. Keitel

Physics Faculty Research & Creative Works

The incoherent inelastic part of the resonance fluorescence spectrum of a laser-driven atom is known as the Mollow spectrum [B. R. Mollow, Phys. Rev. 188, 1969 (1969)]. Starting from this level of description, we discuss theoretical foundations of high-precision spectroscopy using the resonance fluorescence light of strongly laser-driven atoms. Specifically, we evaluate the leading relativistic and radiative corrections to the Mollow spectrum, up to the relative orders of ( Z α )² and α ( Z α )² , respectively, and Bloch-Siegert shifts as well as stimulated radiative corrections involving off-resonant virtual states. Complete results are provided for …

Weir River Estuary: Land Protection Plan, Chantal Lefebvre, Michelle Portman

Urban Harbors Institute Publications

If economic growth were the only measure of a community’s health and vitality, then the communities of Cohasset, Hingham, and Hull are fairing well. But this economic success is generally accompanied by changes in the physical landscape that can be unsettling for residents, especially when it means more development and expansion at the expense of culturally and socially important open space areas such as parks, woods, and marshes. The rapid pace and fragmented nature of such sprawling development gives communities little opportunity to come to terms with the long-term impacts, which in turn can lead to a sense of powerlessness …

The Prairie Naturalist Volume 36, No.4 December 2004

The Prairie Naturalist

ROADSIDE BIAS IN POINT COUNT SURVEYS AT ARROWWOOD NATIONAL WILDLIFE REFUGE, NORTH DAKOTA ▪ J. S. Dieni and P. Scherr

HISTORY OF GREATER SAGE-GROUSE IN THE DAKOTAS: DISTRIBUTION AND POPULATION TRENDS ▪ . J. T. Smith, L. D. Flake, K. F. Higgins, and G. D. Kobriger

PATCH USE BY A MONOPHAGOUS HERBIVORE IN FRAGMENTED PRAIRIE LANDSCAPES ▪ . M. J. St. Pierre and S. D. Hendrix

SNOWSHOE HARE OCCURRENCE AND WINTER HABITAT ON THE MISSOURI COTEAU IN NORTH DAKOTA ▪ R. K. Murphy 243

HIGH ABUNDANCE OF NESTING LONG-EARED OWLS IN NORTH DAKOTA ▪ R. K. Murphy, L. J. Rosenfield, …

Algorithms For Computing The Distributions Of Sums Of Discrete Random Variables, D. L. Evans, Lawrence Leemis

Arts & Sciences Articles

We present algorithms for computing the probability density function of the sum of two independent discrete random variables, along with an implementation of the algorithm in a computer algebra system. Some examples illustrate the utility of this algorithm.

Alligators As West Nile Virus Amplifiers, Kaci Klenk, Jamie Snow, Katrina Morgan, Richard Bowen, Michael Stephens, Falacia Foster, Paul Gordy, Susan Beckett, Nicholas Komar, Duane Gubler, Michael Bunning

United States Department of Agriculture Wildlife Services: Staff Publications

Recent evidence suggests that American alligators (Alligator mississippiensis) may be capable of transmitting West Nile virus (WNV) to other alligators. We experimentally exposed 24 juvenile alligators to WNV parenterally or orally. All became infected, and all but three sustained viremia titers >5.0 log₁₀ PFU/mL (a threshold considered infectious for Culex quinquefasciatus mosquitoes) for 1 to 8 days. Noninoculated tankmates also became infected. The viremia profiles and multiple routes of infection suggest alligators may play an important role in WNV transmission in areas with high population densities of juvenile alligators.

Generating Linear Orders Of Events For Geospatial Domains, Suzannah Hall

Electronic Theses and Dissertations

Events in the world do not occur in neat chronological order, but may take place, for example, during or overlapping each other, or as simultaneous events. Efficient summaries of real-world events are important in many disciplines and require events to be modeled in a linear fashion. This thesis focuses on modeling events as intervals and using relations between the events to derive linear orders from more complex partially ordered sets. A method is developed for mapping Allen's thirteen temporal relations to only two relations, before and equals, which allow a linear ordering of all events present in the set. This …

Mössbauer Spectral Study Of The Magnetocaloric Femnp₁₋ₓasₓ Compounds, Raphäel P. Hermann, Ojied Tegus, Ekkehard H. Brück, K. H. J. Buschow, Frank R. De Boer, Gary J. Long, Fernande Grandjean

Chemistry Faculty Research & Creative Works

The magnetic phase transitions in the FeMnP_1-xAs_x compounds with x= 0.25, 0.35, 0.45, 0.50, and 0.55, have been studied by iron-57 Mössbauer spectroscopy. The ferromagnetic and antiferromagnetic spectra have been analyzed with a model that takes into account the random distribution of the P and As near-neighbor anions of a given iron site. This distribution is a binomial distribution of the contributions to the spectra of each iron with n As near neighbors. A magnetostriction model has been used to characterize the temperature induced paramagnetic to ferromagnetic first-order phase transition and order parameters, η_F=2.6, 2.3, …

Topology Control Of Ad Hoc Wireless Networks For Energy Efficiency, Maggie Xiaoyan Cheng, Mihaela Cardei, Jinhua Sun, Xiaochun Cheng, Lusheng Wang, Yinfeng Xu, Ding-Zhu Du

Computer Science Faculty Research & Creative Works

In ad hoc wireless networks, to compute the transmission power of each wireless node such that the resulting network is connected and the total energy consumption is minimized is defined as a Minimum Energy Network Connectivity (MENC) problem, which is an NP-complete problem. In this paper, we consider the approximated solutions for the MENC problem in ad hoc wireless networks. We present a theorem that reveals the relation between the energy consumption of an optimal solution and that of a spanning tree and propose an optimization algorithm that can improve the result of any spanning tree-based topology. Two polynomial time …

Introduction To The Legal Foundation Of Federal Land Management, University Of Colorado Boulder. Natural Resources Law Center

Introduction to the Legal Foundation of Federal Land Management (December 1-3)

1 v. (various pagings) : ill., maps ; 28 cm

Materials prepared for the course held at the National Center for Atmospheric Research in Boulder, Colorado on December 1-3, 2004

Course instructors: Charles Wilkinson; Sarah Krakoff; Kathryn Mutz; Ann Morgan; Maggie Fox

Contents:

Introduction -- Agenda -- Summaries of laws -- Case studies. Travel management; Oil and gas development; Timber/fuels reduction -- How to influence agency decision makers -- Natural resource related legal and policy resources for the non-legal professional

Two High School Teachers’ Initial Use Of Geometers Sketchpad: Issues Of Implementation, Kathryn G. Shafer

Dissertations

This study documents two teachers' instructional practices as they learn and incorporate Geometer's Sketchpad (GSP) activities into their curriculum. The researcher (as a mentor) worked closely with two high school geometry teachers following a case study methodology. As a secondary goal, this study examined the use of a mentor as a professional development model to assist classroom teachers in the learning and implementation of Geometer'sSketchpad. Data were gathered through interviews, surveys, observations, classroom videotape, participant journal entries, as well as researcher field notes.

Results are reported in the areas of goals of instruction, method of instruction, role of the teacher, …

Teaching Fractions, Natalie Miles

Mahurin Honors College Capstone Experience/Thesis Projects

Because fractions are a vital part of mathematics instruction in schools and can be found in real life, it is important that all students understand and be able to utilize them. Teachers should choose strategies that will work best for their individual students, taking into account the various ways their students learn and the fraction knowledge students already possess. To effectively teach fractions, teachers must find ways to prompt student interest. Teachers can accomplish this through the use of technology. games. and manipulatives. Effective teachers must take into account the cultural diversity of their students. Teachers must be able to …

Initial-Value Problem For Three-Dimensional Disturbances In A Hypersonic Boundary Layer, Eric Forgoston, Anatoli Tumin

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

An initial-value problem is formulated for a threedimensional wave packet in a hypersonic boundary layer flow. The problem is solved using a Laplace transform with respect to time and Fourier transforms with respect to the streamwise and spanwise coordinates. The solution can be presented as a sum of modes consisting of continuous and discrete spectra of temporal stability theory. Two discrete modes, known as Mode S and Mode F, are of interest since they may be involved in a laminar-turbulent transition scenario. The continuous and discrete spectrum are analyzed numerically, and the following features are revealed: (1) the synchronism of …

Using Fine-Grained Cycle Stealing To Improve Throughput, Efficiency And Response Time On A Dedicated Cluster While Maintaining Quality Of Service, Gary Stiehr

All Computer Science and Engineering Research

For various reasons, a dedicated cluster is not always fully utilized even when all of its processors are allocated to jobs. This occurs any time that a running job does not use 100% of each of the processors allocated to it. Keeping in mind the needs of both the cluster’s system administrators and its users, we would like to increase the throughput and efficiency of the cluster while maintaining or improving the average turnaround time of the jobs and the quality of service of the “primary” jobs originally scheduled on the cluster. To increase the throughput and efficiency of the …

Teacher In The Spotlight, Aaron Beaumont

Lake Union Herald

No abstract provided.

Spatial Distribution Of Competing Ions Around Dna In Solution, Kurt Andresen, R. Das, Hye Yoon Park, H. Smith, Lisa W. Kwok, Jessica S. Lamb, E. J. Kirkland, D. Herschlag, K. D. Finkelstein, Lois Pollack

Physics and Astronomy Faculty Publications

The competition of monovalent and divalent cations for proximity to negatively charged DNA is of biological importance and can provide strong constraints for theoretical treatments of polyelectrolytes. Resonant x-ray scattering experiments have allowed us to monitor the number and distribution of each cation in a mixed ion cloud around DNA. These measurements provide experimental evidence to support a general theoretical prediction: the normalized distribution of each ion around polyelectrolytes remains constant when ions are mixed at different ratios. In addition, the amplitudes of the scattering signals throughout the competition provide a measurement of the surface concentration parameter that predicts the …

Vertical Nanowire Light-Emitting Diode, Rolf Könenkamp, Robert Campbell Word, C. Schlegel

Physics Faculty Publications and Presentations

We report room-temperature, white-color electroluminescence in vertically oriented ZnO nanowires. Excitonic luminescence around 380 nm is observed as a shoulder on a broader defect-related band covering all of the visible range and centered at 620 nm. The ZnO nanowires are grown in a low-temperature process on SnO₂-coated glass substrates, employing a technique that is suitable for large-area applications. The nanowires are robustly encapsulated in a thin polystyrene film deposited from high-molecular-weight solutions. Electron injection occurs through the transparent SnO₂ layer, while hole injection is mediated by a p-doped polymer and an evaporated Au contact. Stable device operation …

The Meyer-Neldel Rule For Diodes In Forward Bias, Ralf Widenhorn, Michael Fitzgibbons, Erik Bodegom

Physics Faculty Publications and Presentations

We analyzed the temperature dependence of the forward current of a silicon diode. Instead of representing the data in the ordinarily used current versus voltage graph, the currents are plotted for different voltages as a function of the inverse temperature. The constant voltage curves can be fitted linearly and the extrapolations of the fits seem to merge to one common focal point. Hence, we demonstrate that a real diode follows the Meyer-Neldel rule (MNR). It is shown that the MNR is due to a shift of the current from ideal-diode to high-injection-diode behavior. We will argue that the merging of …

Risk Perceptions Of Adults In The Town Of Unicoi, Tennessee, Regarding The Possible Building Of A Uranium Enrichment Plant., Shannon Kathleen Sellards

Electronic Theses and Dissertations

A prolonged siting controversy for a uranium enrichment facility has occurred in the Town of Unicoi, Tennessee. One hundred-seventy residents of Unicoi were interviewed using a questionnaire regarding the building of a proposed uranium enrichment facility for Unicoi. The questionnaire sought to determine relationships between residents’ risk perceptions and 18 variables. When the Fisher’s exact procedure was applied at α< 0.05, the results indicated several associations. Odds ratio measured the strength of association. Results are reported as crude measures of association. Risk perceptions were influenced by the choice of possible locations for the facility [p=0.0003; OR=32.6]. Residents' risk perceptions were associated with a history of working with nuclear materials [p=0.0476; OR=3.2]. Finally, risk perceptions were associated with residents' beliefs that the nuclear facility would affect their health [p=0.0001; OR=18.8]. These results are discussed in light of risk perception and communication theories.

The Effect Of Naocl, Ca(Oh)2, Mta And Mtad On Root Dentin Fracture Resistance, Sunil Ilapogu

Loma Linda University Electronic Theses, Dissertations & Projects

Various materials are used for the treatment of immature teeth that have been subjected to trauma or decay. It is not well established what effect these materials may have on the immature root dentin. A concern would be the resistance to fracture of the remaining root dentin. The purpose of this study was to compare the resistance of fracture of bovine teeth treated with sodium hypochlorite, calcium hydroxide, gray MTA and gray MTA in conjunction with MTAD after certain periods of time. One hundred and ninety five freshly extracted, intact bovine incisors were prepared using a modified Haapasalo and Orstavik …

Laboratory Experiments Of Entrainment In Dry Convective Boundary Layers, Harm J.J. Jonker, Thijs Heus, Esther Hagen, Han Van Dop

Physics Faculty Publications

Entrainment in dry convective boundary layers was studied. A saline convection tank set-up was used as a laboratory model for a dry convective atmospheric boundary layer. The entrainment flux was measured using planar laser induced fluorescence (PLIF). It was found that the entrainment flux reveals a much stronger dependence on the inversion strength than large eddy simulations tend to do.

Coordinate Conditions For A Uniformly Accelerated Or Static Plane Symmetric Metric, Preston Jones, Lucas Wanex

Publications

The coordinate conditions for three exact solutions for the metric components of a coordinate system with constant acceleration or of a static plane symmetric gravitational field are presented. First, the coordinate condition that the acceleration of light is constant is applied to the field equations to derive the metric of a coordinate system of constant acceleration. Second, the coordinate conditions required to produce the metrics of Rindler and Lass are applied to the field equations to calculate the components of these two metrics and the coordinate velocities and coordinate accelerations for light of these two metrics are compared to the …

General Brochure, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Brochure about the Energy & Environmental Research Center (EERC), including its philosophy, program areas, and Centers of Excellence.