Digital Commons Network^™

Multigrid Convergence For Second Order Elliptic Problems With Smooth Complex Coefficients, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

The finite element method when applied to a second order partial differential equation in divergence form can generate operators that are neither Hermitian nor definite when the coefficient function is complex valued. For such problems, under a uniqueness assumption, we prove the continuous dependence of the exact solution and its finite element approximations on data provided that the coefficients are smooth and uniformly bounded away from zero. Then we show that a multigrid algorithm converges once the coarse mesh size is smaller than some fixed number, providing an efficient solver for computing discrete approximations. Numerical experiments, while confirming the theory, …

Polynomial Extension Operators. Part I, Leszek Demkowicz, Jay Gopalakrishnan, Joachim Schöberl

Mathematics and Statistics Faculty Publications and Presentations

In this series of papers, we construct operators that extend certain given functions on the boundary of a tetrahedron into the interior of the tetrahedron, with continuity properties in appropriate Sobolev norms. These extensions are novel in that they have certain polynomial preservation properties important in the analysis of high order finite elements. This part of the series is devoted to introducing our new technique for constructing the extensions, and its application to the case of polynomial extensions from H^½(∂K) into H¹(K), for any tetrahedron K.

Asymptotic And Numerical Techniques For Resonances Of Thin Photonic Structures, Jay Gopalakrishnan, Shari Moskow, Fadil Santosa

Mathematics and Statistics Faculty Publications and Presentations

We consider the problem of calculating resonance frequencies and radiative losses of an optical resonator. The optical resonator is in the form of a thin membrane with variable dielectric properties. This work provides two very different approaches for doing such calculations. The first is an asymptotic method which exploits the small thickness and high index of the membrane. We derive a limiting resonance problem as the thickness goes to zero, and for the case of a simple resonance, find a first order correction. The limiting problem and the correction are in one less space dimension, which can make the approach …

A Mixed Method For Axisymmetric Div-Curl Systems, Dylan M. Copeland, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

We present a mixed method for a three-dimensional axisymmetric div-curl system reduced to a two-dimensional computational domain via cylindrical coordinates. We show that when the meridian axisymmetric Maxwell problem is approximated by a mixed method using the lowest order Nédélec elements (for the vector variable) and linear elements (for the Lagrange multiplier), one obtains optimal error estimates in certain weighted Sobolev norms. The main ingredient of the analysis is a sequence of projectors in the weighted norms satisfying some commutativity properties.

The Indefinite Metric Of R. Mrugala And The Geometry Of The Thermodynamical Phase Space, Serge Preston, James Vargo

Mathematics and Statistics Faculty Publications and Presentations

We study an indefinite metric G which was introduced by R. Mrugala and is defined on the contact phase space (P, θ) of a homogeneous thermodynamical system. We describe the curvature properties and the isometry group of the metric G. We established an isomorphism of the space (P, θ, G) with the Heisenberg Lie group H_n, endowed with the right invariant contact structure and the right invariant indefinite metric. The lift of the metric G to the symplectization of contact space (P, θ) and its properties are studied. Finally we introduce the "hyperbolic projectivization" of the space …

Uniform Materials And The Multiplicative Decomposition Of The Deformation Gradient In Finite Elasto-Plasticity, Vincenzo Ciancio, Marina Dolfin, Mauro Francaviglia, Serge Preston

Mathematics and Statistics Faculty Publications and Presentations

In this work we analyze the relation between the multiplicative decomposition F = F e F p of the deformation gradient as a product of the elastic and plastic factors and the theory of uniform materials. We prove that postulating such a decomposition is equivalent to having a uniform material model with two configurations – total φ and the inelastic φ1. We introduce strain tensors characterizing different types of evolutions of the material and discuss the form of the internal energy and that of the dissipative potential. The evolution equations are obtained for the configurations (φ, φ1) and the material …

On The Spectra Of Certain Directed Paths, Carlos Martins Da Fonseca, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We describe the eigenpairs of special kinds of tridiagonal matrices related to problems on traffic on a one-lane road. Some numerical examples are provided.

Denaturation Transition Of Stretched Dna, Andreas Hanke, Martha G. Ochoa, Ralf Metzler

Physics & Astronomy Faculty Publications

We generalize the Poland-Scheraga model to consider DNA denaturation in the presence of an external stretching force. We demonstrate the existence of a force-induced DNA denaturation transition and obtain the temperature-force phase diagram. The transition is determined by the loop exponent c, for which we find the new value c=4ν−1/2 such that the transition is second order with c=1.85DNA, corresponding to a lower melting temperature T(F), in agreement with single-molecule DNA stretching experiments.

Search For Gravitational Waves From Binary Inspirals In S3 And S4 Ligo Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on a search for gravitational waves from the coalescence of compact binaries during the third and fourth LIGO science runs. The search focused on gravitational waves generated during the inspiral phase of the binary evolution. In our analysis, we considered three categories of compact binary systems, ordered by mass: (i) primordial black hole binaries with masses in the range 0.35M⊙

Search Of S3 Ligo Data For Gravitational Wave Signals From Spinning Black Hole And Neutron Star Binary Inspirals, B. P. Abbott, R. Grosso, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on the methods and results of the first dedicated search for gravitational waves emitted during the inspiral of compact binaries with spinning component bodies. We analyze 788 hours of data collected during the third science run (S3) of the LIGO detectors. We searched for binary systems using a detection template family specially designed to capture the effects of the spin-induced precession of the orbital plane. We present details of the techniques developed to enable this search for spin-modulated gravitational waves, highlighting the differences between this and other recent searches for binaries with nonspinning components. The template bank we …

Search For Gravitational Waves Associated With 39 Gamma-Ray Bursts Using Data From The Second, Third, And Fourth Ligo Runs, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We present the results of a search for short-duration gravitational-wave bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray satellite experiments during LIGO’s S2, S3, and S4 science runs. The search involves calculating the crosscorrelation between two interferometer data streams surrounding the GRB trigger time. We search for associated gravitational radiation from single GRBs, and also apply statistical tests to search for a gravitational-wave signature associated with the whole sample. For the sample examined, we find no evidence for the association of gravitational radiation with GRBs, either on a single-GRB basis or on a statistical basis. Simulating gravitational-wave bursts …

All-Sky Search For Periodic Gravitational Waves In Ligo S4 Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1000 Hz and with the frequency’s time derivative in the range −1×10−8  Hz s−1 to zero. Data from the fourth LIGO science run (S4) have been used in this search. Three different semicoherent methods of transforming and summing strain power from short Fourier transforms (SFTs) of the calibrated data have been used. The first, known as StackSlide, averages normalized power from each SFT. A “weighted Hough” scheme is also developed and used, which also allows for a multi-interferometer search. The third method, …

The Bulletin, Undergraduate Catalog 2008-2009 (2008), Minnesota State University Moorhead

Undergraduate Bulletins (Catalogs)

No abstract provided.

Hiv/Aids: Can We Get Any Lessons From Assessment In Zimbabwe Education?, Crispen Dirwai Ph.D.

Electronic Journal for Inclusive Education

HIV/AIDS is such a traumatizing experience not to be left to the medical fraternity alone, but to education as well. In the quest for a sustainable reduction in HIV prevalence rates in Less Developed Countries (LEDCs), a revisit on the role of inclusion of HIV in assessment is perceived crucial. There is no doubt HIV/AIDS is still claiming lives many in sub Saharan Africa, teachers and their students included hence the need for different platforms from which the issue can be talked about. Down playing the power of educational measurement in behavioral change is quite an unfortunate omission in itself. …

Sediment Transport And Contaminant Behavior In The Buffalo River, New York: Implications For River Management, Jill Singer, Patrick Mclaren

Earth Sciences Faculty Publications

The lower 9 km of the Buffalo River that flows into the eastern end of Lake Erie has been designated by the International Joint Commission as a Great Lakes area of concern (AoC) because of poor water quality, degraded riparian and river habitat, and contaminated sediments—impairments related to a long history of contamination from the industrial legacy of the past century. As a designated AoC, attention is presently focused on sediment remediation, an endeavor requiring an assessment of the relationship between sediment transport processes and sediment contaminant concentrations. In 1990 a pilot sediment trend analysis (STA) revealed an upriver return …

Expectation-Maximization Optical Tomosynthetic Volume Imaging, Philip M. Hanna

Browse all Theses and Dissertations

Optical tomosynthetic imaging of 3-D objects from disparate 2-D images has been limited in the past by a lack of algorithmic enforcement of physical constraints, in particular within-scene obscuration and object self-occlusion. This paper presents a stochastic observation model of a tomosynthetic collection that explicitly includes an obscuration operator that is unknown by the sensor. The expectation-maximization algorithm is used to iteratively estimate the obscuration operator and to reconstruct the 3-D volume of interest. Explicit inclusion of obscuration effects greatly enhances the spatial and spectral accuracy of 3-D results without use of costly post-processing techniques. Performance metrics are introduced and …

Botminer: Clustering Analysis Of Network Traffic For Protocol- And Structure-Independent Botnet Detection, Guofei Gu, Roberto Perdisci, Junjie Zhang, Wenke Lee

Computer Science and Engineering Faculty Publications

Botnets are now the key platform for many Internet attacks, such as spam, distributed denial-of-service (DDoS), identity theft, and phishing. Most of the current botnet detection approaches work only on specific botnet command and control (C&C) protocols (e.g., IRC) and structures (e.g., centralized), and can become ineffective as botnets change their C&C techniques. In this paper, we present a general detection framework that is independent of botnet C&C protocol and structure, and requires no a priori knowledge of botnets (such as captured bot binaries and hence the botnet signatures, and C&C server names/addresses). We start from the definition and essential …

Learning Expressive Ontologies, Johanna Volker, Peter Haase, Pascal Hitzler

Computer Science and Engineering Faculty Publications

No abstract provided.

Hrests: An Html Microformat For Describing Restful Web Services, Jacek Kopecky, Karthik Gomadam, Tomas Vitvar

Kno.e.sis Publications

The Web 2.0 wave brings, among other aspects, the Programmable Web: increasing numbers of Web sites provide machine-oriented APIs and Web services. However, most APIs are only described with text in HTML documents. The lack of machine-readable API descriptions affects the feasibility of tool support for developers who use these services. We propose a microformat called hRESTS (HTML for RESTful Services) for machine-readable descriptions of Web APIs, backed by a simple service model. The hRESTS microformat describes main aspects of services, such as operations, inputs and outputs. We also present two extensions of hRESTS: SA-REST, which captures the facets of …

Joint Extraction Of Compound Entities And Relationships From Biomedical Literature, Cartic Ramakrishnan, Pablo N. Mendes, Rodrigo A.T.S. De Gama, Guilherme C.N. Ferreira, Amit P. Sheth

Kno.e.sis Publications

In this paper we identify some limitations of contemporary information extraction mechanisms in the context of biomedical literature. We present an extraction mechanism that generates structured representations of textual content. Our extraction mechanism achieves this by extracting compound entities, and relationships between them, occuring in text. A detailed evaluation of the relationship and compound entities extracted is presented. Our results show over 62% average precision across 8 relationship types tested with over 82% average precision for compound entity identification1.

Targeted Content Delivery For Social Media Content, Meenakshi Nagarajan, Kamal Baid, Amit P. Sheth, Shaojun Wang

Kno.e.sis Publications

Spotting contextually relevant keywords is fundamental to effective content suggestions on the Web. In this regard, misspellings, entity variations and off-topic discussions in content from Social Media pose unique challenges. Here, we present an algorithm that assists content delivery systems by identifying contextually relevant keywords and eliminating off-topic keywords. A preliminary user study over data from MySpace and Facebook clearly suggests the usefulness of our work in delivering more targeted content suggestions.

Traveling The Semantic Web Through Space, Theme And Time, Amit P. Sheth, Matthew Perry

Kno.e.sis Publications

In this installment of Semantics and Services, we further develop the idea of spatial, temporal, and thematic (STT) processing of semantic Web data and describe the Web infrastructure needed to support it. Starting from Ramesh Jain's vision of the EventWeb as a view of what's possible with a Web that better accommodates all three dimensions of event-related information (thematic, spatial, and temporal), we outline the architecture needed to support it and current research that aims to realize it.

Content Is Not Enough: A History Of Secondary Earth Science Teacher Preparation With Recommendations For Today, Elizabeth B. Lewis

Department of Teaching, Learning, and Teacher Education: Faculty Publications

Secondary geoscience education has its roots in geography and physiographic education from the turn of the 20th century. High school Earth science reached a peak during the late 1960s and 1970s, after plate tectonic theory revolutionized geology. The production of Earth science teachers, unlike biology teachers, has never reached full capacity, which has likely contributed to the lesser presence and status of Earth and space science in U.S. high schools today. Historically, the geoscience community has focused on enriching teachers' geoscience content knowledge, but modern Earth and space science teachers need more than just content knowledge.

Based on current science …

Comparative Analysis Of Eo-1 Ali And Hyperion, And Landsat Etm+ Data For Mapping Forest Crown Closure And Leaf Area Index, Ruiliang Pu, Peng Gong, Qian Yu

School of Geosciences Faculty and Staff Publications

In this study, a comparative analysis of capabilities of three sensors for mapping forest crown closure (CC) and leaf area index (LAI) was conducted. The three sensors are Hyperspectral Imager (Hyperion) and Advanced Land Imager (ALI) onboard EO-1 satellite and Landsat-7 Enhanced Thematic Mapper Plus (ETM+). A total of 38 mixed coniferous forest CC and 38 LAI measurements were collected at Blodgett Forest Research Station, University of California at Berkeley, USA. The analysis method consists of (1) extracting spectral vegetation indices (VIs), spectral texture information and maximum noise fractions (MNFs), (2) establishing multivariate prediction models, (3) predicting and mapping pixel-based …

Amvc: A Loosely-Coupled Architecture For Component-Based Clients, Brendan Lawlor

Theses

There is an architectural deficit in most currently undertaken rich client applications: In n-tier applications the presentation layer is represented as a single layer. This is as true of browser-based rich clients (Rich Internet Applications) as of rich desktop clients since both are designed along component-based, event-driven lines. The result of creating rich clients without sufficient application architecture underpinning is often tightly-coupled code of unnecessary complexity, with the associated high cost of maintenance. No commonly understood pattern is currently evident that would allow rich client components to be combined into a loosely coupled application. This paper describes the theory and …

The Rollamo 2008, Missouri University Of Science And Technology

Yearbooks

No abstract provided.

Dielectronic Recombination And Stability Of Warm Gas In Active Galactic Nuclei, Susmita Chakravorty, Ajit K. Kembhavi, Martin Elvis, Gary J. Ferland, N. R. Badnell

Physics and Astronomy Faculty Publications

Understanding the thermal equilibrium (stability) curve may offer insights into the nature of the warm absorbers often found in active galactic nuclei. Its shape is determined by factors such as the spectrum of the ionizing continuum and the chemical composition of the gas. We find that the stability curves obtained under the same set of the above-mentioned physical factors, but using recently derived dielectronic recombination rates, give significantly different results, especially in the regions corresponding to warm absorbers, leading to different physical predictions. Using the current rates we find a larger probability of having a thermally stable warm absorber at …

Really Leaving No Child Behind: How The Supreme Court's Student Speech Doctrine Compromises Modern Education Reform - And How It Can Use The In Loco Parentis Doctrine To Change It, Scott J. Street

Richmond Public Interest Law Review

tudent speech" doctrine defined by Tinker in favor of an in loco parentis standard that defers to the expertise of school officials in maintaining a safe, effective, and orderly school environment. Contrary to what its critics assume, an in loco parentis standard would not give school officials carte blanche to violate their students' rights. It would, for example, prohibit school officials from discriminating against students on the basis of viewpoint. But as long as Tinker's student speech doctrine survives, efforts to improve our schools and prepare our children for the rigors of the twenty-first century will suffer. The in loco …

Mistaken Bids And Unilateral Mistaken Assumptions, A New Solution For An Old Problem?, John D. Mccamus

Articles & Book Chapters

The “two-contract” analysis of the Supreme Court of Canada’s decision in Ron Engineering has created a very substantial obstacle to relief for mistaken bidders who discover calculation errors upon the opening of the bids. Nonetheless, Canadian courts are inclined to narrowly distinguish that analysis and grant relief in cases of extreme error in order to avoid unduly onerous penalties for mistaken bidders and large unearned windfalls for issuers of invitations to bid. This article argues that recent decisions of Canadian appellate courts articulating a rule which would excuse bidders where the burden imposed by the miscalculation is so grossly disproportionate …

Digital Media John Deere, Nebraska Tractor Test Lab

Nebraska Tractor Tests

Images, videos and audios of 2008 John Deere Tractor Testing. Taken during March and April of 2008.