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2006

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Articles 241 - 270 of 5872

Full-Text Articles in Physical Sciences and Mathematics

Ahlfors Type Estimates For Perimeter Measures In Carnot-Carathéodory Spaces, Luca Capogna, Nicola Garofalo Dec 2006

Ahlfors Type Estimates For Perimeter Measures In Carnot-Carathéodory Spaces, Luca Capogna, Nicola Garofalo

Mathematics Sciences: Faculty Publications

We study the relationship between the geometry of hypersurfaces in a Carnot-Carathéodory (CC) space and the Ahlfors regularity of the corresponding perimeter measure. To this end we establish comparison theorems for perimeter estimates between an hypersurface and its tangent space, and between a CC geometry and its "tangent" Carnot group structure.


Implicit Online Learning With Kernels, Li Cheng, S. V. N. Vishwanathan, Dale Schuurmans, Shaojun Wang, Terry Caelli Dec 2006

Implicit Online Learning With Kernels, Li Cheng, S. V. N. Vishwanathan, Dale Schuurmans, Shaojun Wang, Terry Caelli

Kno.e.sis Publications

We present two new algorithms for online learning in reproducing kernel Hilbert spaces. Our first algorithm, ILK (implicit online learning with kernels), employs a new, implicit update technique that can be applied to a wide variety of convex loss functions. We then introduce a bounded memory version, SILK (sparse ILK), that maintains a compact representation of the predictor without compromising solution quality, even in non-stationary environments. We prove loss bounds and analyze the convergence rate of both. Experimental evidence shows that our proposed algorithms outperform current methods on synthetic and real data.


Regression Cubes With Lossless Compression And Aggregation, Yixin Chen, Guozhu Dong, Jiawei Han, Jian Pei, Benjamin W. Wah, Jianyong Wang Dec 2006

Regression Cubes With Lossless Compression And Aggregation, Yixin Chen, Guozhu Dong, Jiawei Han, Jian Pei, Benjamin W. Wah, Jianyong Wang

Kno.e.sis Publications

As OLAP engines are widely used to support multidimensional data analysis, it is desirable to support in data cubes advanced statistical measures, such as regression and filtering, in addition to the traditional simple measures such as count and average. Such new measures will allow users to model, smooth, and predict the trends and patterns of data. Existing algorithms for simple distributive and algebraic measures are inadequate for efficient computation of statistical measures in a multidimensional space. In this paper, we propose a fundamentally new class of measures, compressible measures, in order to support efficient computation of the statistical models. For …


Simple Braids For Surface Homeomorphisms, Kamlesh Parwani Dec 2006

Simple Braids For Surface Homeomorphisms, Kamlesh Parwani

Faculty Research and Creative Activity

Let S be a compact, oriented surface with negative Euler characteristic and f:S→S be a homeomorphism isotopic to the identity. If there exists a periodic orbit with a non-zero rotation vector (p→,q), then there exists a simple braid with the same rotation vector.


Moving Object Tracking: Seeking Extensible Solutions, Jeremy Pack Dec 2006

Moving Object Tracking: Seeking Extensible Solutions, Jeremy Pack

Undergraduate Honors Capstone Projects

Moving object tracking is a difficult field with no "best" solution. The documents contained here detail software that was developed in order to perform tracking of objects that are in the line of sight of multiple cameras. Some of the software developed is already in use by the US Army Dugway Proving Ground. Other software represents prototype or early development code. This software was written by Jeremy Pack, who was the lead programmer, and Luke Andrew at the Space Dynamics Laboratory in Logan, Utah.


Simple Braids For Surface Homeomorphisms, Kamlesh Parwani Dec 2006

Simple Braids For Surface Homeomorphisms, Kamlesh Parwani

Faculty Research and Creative Activity

Let S be a compact, oriented surface with negative Euler characteristic and f:S→S be a homeomorphism isotopic to the identity. If there exists a periodic orbit with a non-zero rotation vector (p→,q), then there exists a simple braid with the same rotation vector.


Grassland Songbirds In A Dynamic Management Landscape: Behavioral Responses And Management Strategies, Noah G. Perlut, Allan M. Strong, Therese M. Donovan, Neil J. Buckley Dec 2006

Grassland Songbirds In A Dynamic Management Landscape: Behavioral Responses And Management Strategies, Noah G. Perlut, Allan M. Strong, Therese M. Donovan, Neil J. Buckley

Environmental Studies Faculty Publications

In recent decades, earlier and more frequent harvests of agricultural grasslands have been implicated as a major cause of population declines in grassland songbirds. From 2002 to 2005, in the Champlain Valley of Vermont and New York, USA, we studied the reproductive success of Savannah Sparrows (Passerculus sandwichensis) and Bobolinks (Dolichonyx oryzivorus) on four grassland treatments: (1) early-hayed fields cut before 11 June and again in early- to mid-July; (2) middle-hayed fields cut once between 21 June and 10 July; (3) late-hayed fields cut after 1 August; and (4) rotationally grazed pastures. Both the number of …


New Tests Of Univariate Symmetry Based On The Gini Mean Difference, Hend Ouda Dec 2006

New Tests Of Univariate Symmetry Based On The Gini Mean Difference, Hend Ouda

Dissertations

Gini mean difference (GMD) was proposed as a measure of income inequality by Corrado Gini in 1912. Since then it has been widely applied - mostly in theeconomics, but also in statistical and social science research.

Four statistical tests of univariate symmetry are being proposed---all based on the comparison of variation below and above the median (known or estimated) measured by the GMD. These tests are applicable to the data from populations with median known and unknown, and each of them has its rank-basedcounterpart, so they can also be used for ordinal data.

A Monte Carlo simulation study was performed …


Synthesis And Fundamental Characterization Of Nanoparticles And Their Clusters, Ke Du Dec 2006

Synthesis And Fundamental Characterization Of Nanoparticles And Their Clusters, Ke Du

Dissertations

Nanoparticles of gold derivatized with monolayers of thiocarboxylic acid ligands, core/shell nanoparticle composites of gold and silica, gold-glutathioneclusters, and titania nanoparticles were synthesized and their surface properties (extent of ligand coverage, net negative charge, and zeta potential) characterized by capillary electrophoresis as a function of pH, ionic strength, and dielectric constant for the first time. The hydrodynamic radii of thenanoparticles were determined by dynamic laser light scattering and used to calculate the net surface charge, extent of ligand coverage, and zeta potentials ofthe nanoparticles from electrophoresic mobilities. The ligand derivatized nanoparticles had similar hydrodynamic radius of about 20 nm which …


Single Top Quark Production At The Fermilab Tevatron: Threshold Resummation And Finite-Order Soft Gluon Corrections, Nikolaos Kidonakis Dec 2006

Single Top Quark Production At The Fermilab Tevatron: Threshold Resummation And Finite-Order Soft Gluon Corrections, Nikolaos Kidonakis

Faculty Articles

I present a calculation of threshold soft-gluon corrections to single top-quark production in p(p) collisions via all partonic processes in the t and s channels and via associated top quark and W boson production. The soft-gluon corrections are formally resummed to all orders, and finite-order expansions of the resummed cross section are calculated through next-to-next-to-next-to-leading-order (NNNLO) at next-to-leading logarithmic (NLL) accuracy. Numerical results for single top-quark production at the Tevatron are presented, including the dependence of the cross sections on the top-quark mass and on the factorization and renormalization scales. The threshold corrections in the t channel are small while …


Investigation Of Oxy-Anion Legand Adsorption Onto Surfaces Of Iron Oxide And Bacteria In Groundwater Aquifers, Haile Mengistu Dec 2006

Investigation Of Oxy-Anion Legand Adsorption Onto Surfaces Of Iron Oxide And Bacteria In Groundwater Aquifers, Haile Mengistu

Dissertations

We have measured adsorption of dissolved phosphate onto synthetic hydrous ferric oxide (HFO), dissolved arsenate and chromate onto the cell membrane of a bacterium species, S. putrefaciens as a function of pH, ionic strength, and relative concentrations of the respective oxy-ligands. Our experimental data were used to constrain optimal values for surface complexation reactions involving dissolved oxi-ligands (phosphate, and chromate) and the HFO surface and the cell membrane of S. putrefaciens respectively according to the diffuse layer model.

Our results provide a more accurate fit to experimental measurements over a broader range of pH (3 - 12), ionic strength and …


Co-Evolution Of Agent-Oriented Conceptual Models And Caso Agent Programs, A. Dasgupta, Aneesh Krishna, Aditya K. Ghose Dec 2006

Co-Evolution Of Agent-Oriented Conceptual Models And Caso Agent Programs, A. Dasgupta, Aneesh Krishna, Aditya K. Ghose

Faculty of Informatics - Papers (Archive)

Agent-Oriented conceptual modelling notations are highly effective in representing requirements from an intentional stance and answering questions such as what goals exist, how key actors depend on each other and what alternatives must be considered. In this paper, we suggest an approach to executing i* models by translating these into set of interacting agents implemented in the CASO language. In addition, we suggest a hybrid modelling, or co-evolution, approach in which i* models and CASO agent programs are concurrently maintained and updated, while retaining some modicum of loose consistency between the two. This allows us to benefit from the complementary …


Determining Environmental Drivers Of Fish Community Structure Along The Coast Of Maine, Adrian Jordaan Dec 2006

Determining Environmental Drivers Of Fish Community Structure Along The Coast Of Maine, Adrian Jordaan

Electronic Theses and Dissertations

The work presented here was conceived to determine whether structure in marine communities could be related to multiple scaled environmental parameters, as seen in lake and stream systems. Four datasets collected from 2001 to 2005 were used. The datasets ranged from local scale tidepool and estuarine surveys, to more regional intertidal/subtidal surveys and conclude using a coast-wide trawl survey. Initially, a bootstrap program for running principal component analysis (PCA) was developed and tested for utility with additional information from Pearson correlation coefficients. The bootstrap-PC A program was capable of determining confidence limits for correlations amongst species. The results from analysis …


Topology Of Attractors From Two-Piece Expanding Maps, Youngna Choi Dec 2006

Topology Of Attractors From Two-Piece Expanding Maps, Youngna Choi

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

In this paper we study the topology of the invariant sets derived from two-piece expanding maps. We classify the conditions under which the invariant sets are topological attractors, and show that the set of attractors is open and dense in the set of invariant sets derived by two-piece expanding maps.


Don't Be A Phish: Steps In User Education, Stefan Robila, James W. Ragucci Dec 2006

Don't Be A Phish: Steps In User Education, Stefan Robila, James W. Ragucci

Department of Computer Science Faculty Scholarship and Creative Works

Phishing, e-mails sent out by hackers to lure unsuspecting victims into giving up confidential information, has been the cause of countless security breaches and has experienced in the last year an increase in frequency and diversity. While regular phishing attacks are easily thwarted, designing the attack to include user context information could potentially increase the user's vulnerability. To prevent this, phishing education needs to be considered. In this paper we provide an overview of phishing education, focusing on context aware attacks and introduce a new strategy for educating users by combining phishing IQ tests and class discussions. The technique encompasses …


Use Of Remote Sensing Applications And Its Implications To The Society, Stefan Robila Dec 2006

Use Of Remote Sensing Applications And Its Implications To The Society, Stefan Robila

Department of Computer Science Faculty Scholarship and Creative Works

Remote sensing, i.e. the technology that allows measuring object's properties from a distance, is currently undergoing tremendous advances in both precision and areas of applicability. Our study provides an overview of the recent developments in RS applications and their implications to the society. This was approached from three distinct directions, all with significant influence on the human's perception of the technology. First, we discuss how disaster prevention, reaction, and recovery can be supported by remote sensing. Next, we look at the popular view of remote sensing, as illustrated by media and commercial applications. Finally, we discuss legal implication of sensing …


Linear Conditions Imposed On Flag Varieties, Julianna S. Tymoczko Dec 2006

Linear Conditions Imposed On Flag Varieties, Julianna S. Tymoczko

Mathematics Sciences: Faculty Publications

We study subvarieties of the flag variety called Hessenberg varieties, defined by certain linear conditions. These subvarieties arise naturally in applications including geometric representation theory, number theory, and numerical analysis. We describe completely the homology of Hessenberg varieties over GLn(ℂ) and show that they have no odd-dimensional homology. We provide an explicit geometric construction which partitions each Hessenberg variety into pieces homeomorphic to affine space. We characterize these affine pieces by fillings of Young tableaux and show that the dimension of the affine piece can be computed by combinatorial rules generalizing the Eulerian numbers. We give an equivalent formulation of …


Generating Paraphrases With Greater Variation Using Syntactic Phrases, Rebecca Diane Madsen Dec 2006

Generating Paraphrases With Greater Variation Using Syntactic Phrases, Rebecca Diane Madsen

Theses and Dissertations

Given a sentence, a paraphrase generation system produces a sentence that says the same thing but usually in a different way. The paraphrase generation problem can be formulated in the machine translation paradigm; instead of translation of English to a foreign language, the system translates an English sentence (for example) to another English sentence. Quirk et al. (2004) demonstrated this approach to generate almost 90% acceptable paraphrases. However, most of the sentences had little variation from the original input sentence. Leveraging syntactic information, this thesis project presents an approach that successfully generated more varied paraphrase sentences than the approach of …


Probabilistic Localization Of Mobile Ad Hoc Networks, Rui Huang Dec 2006

Probabilistic Localization Of Mobile Ad Hoc Networks, Rui Huang

Computer Science and Engineering Dissertations

The mobile ad hoc network localization problem deals with estimating the physical location of the nodes that do not have a direct way (e.g., GPS) to determine their own locations. Being an enabling technology that is considered essential to the success of the future implementation of ad hoc networks in the real world, localization is a fundamental problem that needs to be solved with the best possible accuracy and efficiency. For this research, we study the localization problem in its various incarnations such as localization through static beacons, mobile beacons, dynamically deployed beacons and link longevity estimation based on relative …


Derelict Blue Crab Trap Impacts On Marine Fisheries In The Lower York River, Virginia, Kirk J. Havens, Donna Marie Bilkovic, David Stanhope, Kory Angstadt, Carl Hershner, Center For Coastal Resources Management, Virginia Institute Of Marine Science Dec 2006

Derelict Blue Crab Trap Impacts On Marine Fisheries In The Lower York River, Virginia, Kirk J. Havens, Donna Marie Bilkovic, David Stanhope, Kory Angstadt, Carl Hershner, Center For Coastal Resources Management, Virginia Institute Of Marine Science

Reports

In Virginia, an examination of existing derelict trap data retrieved from Chesapeake Bay Multispecies Monitoring and Assessment Program (ChesMMAP) trawl surveys shows the potential effect of derelict traps on fish communities in Virginia waters (Bonzek and Latour 2005). Since 2002, ChesMMAP has attempted to sample 90 stations in the mainstem Chesapeake Bay ranging from the southern edge of the Susquehanna Flats to the Bay mouth in all depths to a minimum of 10 feet during each cruise. There are approximately 4-5 cruises per year and a large mesh bottom trawl is used to capture adult fish of a variety of …


Mems Mobile Gis: A Spatially Enabled Fish Habitat Management System, Andrea Rizzini, Keith Gardiner, Michela Bertolotto, James Carswell Dec 2006

Mems Mobile Gis: A Spatially Enabled Fish Habitat Management System, Andrea Rizzini, Keith Gardiner, Michela Bertolotto, James Carswell

Conference papers

Spatially enabled computing can provide assistance to both web-based and mobile users by exploiting positional information and associated contextual knowledge. The Mobile Environmental Management System (MEMS) is a proof of concept prototype that has been developed in order to simplify administrative duties of biologists at the Department of Fisheries and Oceans (DFO), Canada. MEMS aims to deliver contextaware functionality aided by visualization, analysis and manipulation of spatial and attribute datasets. The resulting application delivers a set of functions and services that aids the DFO’s biologists in making everyday management decisions


Issues During The Inversion Of Crosshole Radar Data: Can We Have Confidence In The Outcome?, William P. Clement Dec 2006

Issues During The Inversion Of Crosshole Radar Data: Can We Have Confidence In The Outcome?, William P. Clement

Geosciences Faculty Publications and Presentations

One method of assessing the confidence in modeled features is to compare the results from different inversion schemes. I use synthetic traveltimes calculated from a model of an unconfined aquifer to determine the reliability of crosshole tomography. I compare the inverted models from straight and curved ray approximations to wave propagation. I investigate the effects of added random noise, regularization, the starting model, and the reference model on the curved ray inversion method. I also investigate the effects of different grid sizes for the forward model and of limited ray coverage through the earth model. Understanding the effects of these …


Conformality And Q-Harmonicity In Carnot Groups, Luca Capogna, Michael Cowling Dec 2006

Conformality And Q-Harmonicity In Carnot Groups, Luca Capogna, Michael Cowling

Mathematics Sciences: Faculty Publications

We show that if f is a 1-quasiconformal map defined on an open subset of a Carnot group G, then composition with f preserves Q-harmonic functions. We combine this with a regularity theorem for Q-harmonic functions and an algebraic regularity theorem for maps between Carnot groups to show that f is smooth. We give some applications to the study of rigidity.


Local Energy Decay For Solutions Of Multi-Dimensional Isotropic Symmetric Hyperbolic Systems, Thomas C. Sideris, Becca Thomases Dec 2006

Local Energy Decay For Solutions Of Multi-Dimensional Isotropic Symmetric Hyperbolic Systems, Thomas C. Sideris, Becca Thomases

Mathematics Sciences: Faculty Publications

The local decay of energy is established for solutions to certain linear, multidimensional symmetric hyperbolic systems, with constraints. The key assumptions are isotropy and nondegeneracy of the associated symbols. Examples are given, including Maxwell's equations and linearized elasticity. Such estimates prove useful in treating nonlinear perturbations.


Statistical Thermodynamics And Kinetics Of Dna Multiplex Hybridization Reactions, Albert S. Benight, M. T. Horne, D. J. Fish Dec 2006

Statistical Thermodynamics And Kinetics Of Dna Multiplex Hybridization Reactions, Albert S. Benight, M. T. Horne, D. J. Fish

Chemistry Faculty Publications and Presentations

A general analytical description of the equilibrium and reaction kinetics of DNA multiplex hybridization has been developed. In this approach, multiplex hybridization is considered to be a competitive multichannel reaction process: a system wherein many species can react both specifically and nonspecifically with one another. General equations are presented that can consider equilibrium and kinetic models of multiplex hybridization systems comprised, in principle, of any number of targets and probes. Numerical solutions to these systems for both equilibrium and kinetic behaviors are provided. Practical examples demonstrate clear differences between results obtained from more common simplex methods, in which individual hybridization …


The Proteomics Of N-Terminal Methionine Cleavage, Frédéric Frottin, Aude Martinez, Philippe Peynot, Sanghamitra Mitra, Richard C. Holz, Carmela Giglione, Thierry Meinnel Dec 2006

The Proteomics Of N-Terminal Methionine Cleavage, Frédéric Frottin, Aude Martinez, Philippe Peynot, Sanghamitra Mitra, Richard C. Holz, Carmela Giglione, Thierry Meinnel

Chemistry Faculty Research and Publications

Methionine aminopeptidase (MAP) is a ubiquitous, essential enzyme involved in protein N-terminal methionine excision. According to the generally accepted cleavage rules for MAP, this enzyme cleaves all proteins with small side chains on the residue in the second position (P1′), but many exceptions are known. The substrate specificity of Escherichia coli MAP1 was studied in vitro with a large (>120) coherent array of peptides mimicking the natural substrates and kinetically analyzed in detail. Peptides with Val or Thr at P1′ were much less efficiently cleaved than those with Ala, Cys, Gly, Pro, or Ser in this position. Certain residues …


New Cuoricino Results And Status Of Cuore, O. Cremonesi, R. Ardito, C. Arnaboldi, D.R. Artusa, F.T. Avignone Iii, M. Balata, I. Bandac, M. Barucci, J.W. Beeman, F. Bellini, C. Brofferio, C. Bucci, S. Capelli, F. Capozzi, L. Carbone, S. Cebrian, M. Clemenza, C. Cosmelli, R.J. Creswick, I. Dafinei, A. De Waard, M. Dolinski, H.A. Farach, F. Ferroni, C. Gargiulo, E. Guardincerri, A. Giuliani, P. Gorla, Thomas D. Gutierrez, E.E. Haller, I.G. Irastorza, E. Longo, G. Maier, R. Maruyama, S. Morganti, S. Nisi, C. Nones, E.B. Norman, A. Nucciotti, E. Olivieri, P. Ottonello, M. Pallavicini, E. Palmieri, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, B. Quiter, L. Risegari, C. Rosenfeld, S. Sangiorgio, M. Sisti, A.R. Smith, L. Torres, G. Ventura, N. Xu, L. Zanotti Dec 2006

New Cuoricino Results And Status Of Cuore, O. Cremonesi, R. Ardito, C. Arnaboldi, D.R. Artusa, F.T. Avignone Iii, M. Balata, I. Bandac, M. Barucci, J.W. Beeman, F. Bellini, C. Brofferio, C. Bucci, S. Capelli, F. Capozzi, L. Carbone, S. Cebrian, M. Clemenza, C. Cosmelli, R.J. Creswick, I. Dafinei, A. De Waard, M. Dolinski, H.A. Farach, F. Ferroni, C. Gargiulo, E. Guardincerri, A. Giuliani, P. Gorla, Thomas D. Gutierrez, E.E. Haller, I.G. Irastorza, E. Longo, G. Maier, R. Maruyama, S. Morganti, S. Nisi, C. Nones, E.B. Norman, A. Nucciotti, E. Olivieri, P. Ottonello, M. Pallavicini, E. Palmieri, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, B. Quiter, L. Risegari, C. Rosenfeld, S. Sangiorgio, M. Sisti, A.R. Smith, L. Torres, G. Ventura, N. Xu, L. Zanotti

Physics

CUORICINO is an array of 62 TeO2 bolometers with a total mass of 40.7 kg (11.2 kg of 130Te), operated at about 10 mK to search for ββ(0ν) of 130Te. The detectors are organized as a 14-story tower and intended as a slightly modified version of one of the 19 towers of the CUORE project, a proposed tightly packed array of 988 TeO2 bolometers (741 kg of total mass of TeO2) for ultralow-background searches on neutrinoless double-beta decay, cold dark matter, solar axions, and rare nuclear decays. Started in April 2003 at …


The Distribution And Reproductive Success Of The Western Snowy Plover Along The Oregon Coast - 2006, David J. Lauten, Kathleen J. Castelein, Susan Weston, Krista Eucken, Eleanor P. Gaines Dec 2006

The Distribution And Reproductive Success Of The Western Snowy Plover Along The Oregon Coast - 2006, David J. Lauten, Kathleen J. Castelein, Susan Weston, Krista Eucken, Eleanor P. Gaines

Institute for Natural Resources Publications

Part of the Oregon Bidiversity Information Center Report


Inside Unlv, Diane Russell, Cate Weeks, Shane Bevell, Mamie Peers, Lori Bachand Dec 2006

Inside Unlv, Diane Russell, Cate Weeks, Shane Bevell, Mamie Peers, Lori Bachand

Inside UNLV

No abstract provided.


Complementing Current Active Queue Management Schemes With Rechoke And Receiver-Window Modification (Rwm), Visvasuresh Govindaswamy Dec 2006

Complementing Current Active Queue Management Schemes With Rechoke And Receiver-Window Modification (Rwm), Visvasuresh Govindaswamy

Computer Science and Engineering Dissertations

Explicit Congestion Notification (ECN) and Active Queue Management (AQM) schemes have been proposed for present-day TCP/IP networks to better manage network congestion. ECN enabled AQMs were shown to have a promising advantage over existing drop-tail queues. However, when implemented, they were susceptible to the following problems: 1) the timeout mechanism or the duration of the reception of three duplicate acknowledgements (ACKs), due to early-dropped packets by these AQMs, delays the response time of TCP (in reducing the offered rate) 2) using ECN with these AQMs has its downsides: i) its messages may get delayed or dropped due to congestion in …