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2004

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Articles 721 - 750 of 3873

Full-Text Articles in Physical Sciences and Mathematics

Tcp Processor: Design, Implementation, Operation, And Usage, David V. Schuehler Sep 2004

Tcp Processor: Design, Implementation, Operation, And Usage, David V. Schuehler

All Computer Science and Engineering Research

There is a critical need to perform advanced data processing on network traffic. In order to accom-plish this, protocol processing must first be performed to reassemble individual network packets into consistent data streams representing the exact dataset being transferred between end systems. This task is currently performed by protocol stacks running on end systems. Similar protocol processing opera-tions are needed to process the data on the interior of the network. Given millions of network connections operating on multi-gigabit per second network links, this task is extremely difficult. The TCP-Processor addresses this challenge. It is a hardware circuit designed to perform …


Oscillator Damped By A Constant-Magnitude Friction Force, Avi Marchewka, David S. Abbott, Robert J. Beichner Sep 2004

Oscillator Damped By A Constant-Magnitude Friction Force, Avi Marchewka, David S. Abbott, Robert J. Beichner

Dartmouth Scholarship

Although a simple spring/mass system damped by a friction force of constant magnitude shares many of the characteristics of the simple and damped harmonic oscillators, its solution is not presented in most texts. Closed form solutions for the turning and stopping points can be found using an energy-based approach. A dynamical approach leads to a closed form solution for the position of the mass as a function of time. The main result is that the amplitude of the oscillator damped by a constant magnitude friction force decreases by a constant amount each swing and the motion dies out after a …


Application Of Microgels For Optical Tagging, J. Michael Carthcart, L. Andrew Lyon, Marcus Weck, Robert D. Bock Sep 2004

Application Of Microgels For Optical Tagging, J. Michael Carthcart, L. Andrew Lyon, Marcus Weck, Robert D. Bock

Biology, Chemistry, and Environmental Sciences Faculty Books and Book Chapters

In this paper we present results from our research into the use of microgel-based photonic crystals in an optical tagging application. The basis for this research is the phenomena of self-assembly of hydrogel nano- and microparticles (i.e., microgels) into colloidal crystal Bragg reflectors. Previous research has demonstrated the assembly of Bragg structures that are sensitive in the visible spectral region. This current research focuses on the extension of this process into the infrared regime and the use of these infrared-sensitive structures in the creation of an optical tag. In particular, the research effort emphasizes two primary areas: the development of …


Nonparametric Confidence Intervals For The One- And Two-Sample Problems, Xiao-Hua Zhou, Phillip Dinh Sep 2004

Nonparametric Confidence Intervals For The One- And Two-Sample Problems, Xiao-Hua Zhou, Phillip Dinh

UW Biostatistics Working Paper Series

Confidence intervals for the mean of one sample and the difference in means of two independent samples based on the ordinary-t statistic suffer deficiencies when samples come from skewed distributions. In this article, we evaluate several existing techniques and propose new methods to improve coverage accuracy. The methods examined include the ordinary-t, the bootstrap-t, the biased-corrected acceleration (BCa) bootstrap, and three new intervals based on transformation of the t-statistic. Our study shows that our new transformation intervals and the bootstrap-t intervals give best coverage accuracy for a variety of skewed distributions; and that our new transformation intervals have shorter interval …


An Earlier Lidar Observation Of A Noctilucent Cloud Above Logan, Utah (41.7°N), Joshua P. Herron, Vincent B. Wickwar Sep 2004

An Earlier Lidar Observation Of A Noctilucent Cloud Above Logan, Utah (41.7°N), Joshua P. Herron, Vincent B. Wickwar

Posters

The Atmospheric Lidar Observatory (ALO) Rayleigh-scatter lidar has been operated for 11 years on the Utah State University (USU) campus (41.7o N 111.8o W). During the morning of 22 June 1995 a noctilucent cloud (NLC) was observed with the lidar well away from the twilight periods when NLCs are visible. It lasted for approximately one hour. This observation and a second in 1999 [Wickwar et al., 2002] are very significant because they show the penetration of NLCs equatorward of 50°, which may have important implications for global change. Temperature profiles calculated at hourly intervals were at least 20 …


Effect Of Misreported Family History On Mendelian Mutation Prediction Models, Hormuzd A. Katki Sep 2004

Effect Of Misreported Family History On Mendelian Mutation Prediction Models, Hormuzd A. Katki

Johns Hopkins University, Dept. of Biostatistics Working Papers

People with familial history of disease often consult with genetic counselors about their chance of carrying mutations that increase disease risk. To aid them, genetic counselors use Mendelian models that predict whether the person carries deleterious mutations based on their reported family history. Such models rely on accurate reporting of each member's diagnosis and age of diagnosis, but this information may be inaccurate. Commonly encountered errors in family history can significantly distort predictions, and thus can alter the clinical management of people undergoing counseling, screening, or genetic testing. We derive general results about the distortion in the carrier probability estimate …


Entire Pluricomplex Green Functions And Lelong Numbers Of Projective Currents, Dan Coman Sep 2004

Entire Pluricomplex Green Functions And Lelong Numbers Of Projective Currents, Dan Coman

Mathematics - All Scholarship

Let T be a positive closed current of bidimension (1,1) and unit masson the complex projective space Pn. We prove that the set Valpa(T) of points where T has Lelong number larger than alpha is contained in a complex line if alpha ≥ 2/3, and |V alpa(T ) \ L| ≤ 1 for some complex line L if 1/2 ≤ alpha < 2/3. We also prove that in dimension 2 and if 2/5 ≤ alpha < 1/2, then |V alpha (T ) \ C| ≤ 1 for some conic C.


Evidence Of Linear Lattice Expansion And Covalency Enhancement In Rutile Tio2 Nanocrystals, Guangshe Li, Juliana Boerio-Goates, Brian F. Woodfield, Liping Li Sep 2004

Evidence Of Linear Lattice Expansion And Covalency Enhancement In Rutile Tio2 Nanocrystals, Guangshe Li, Juliana Boerio-Goates, Brian F. Woodfield, Liping Li

Faculty Publications

Lattice variations and bonding characteristics in rutile TiO2 nanocrystals were examined by x-ray diffraction and x-ray photoelectron spectroscopy. With a reduction in the physical dimensions, rutile TiO2 nanocrystals show a linear lattice expansion and an anomalous covalency enhancement in apparent contradiction to the ionicity increase in BaTiO3 and CuO nanocrystals as reported recently by S. Tsunekawa et al. [Phys. Rev. Lett. 2000, 85, 3440] and V. R. Palkar et al. [Phys. Rev. B 1996, 53, 2167]. A surface defect dipole model is proposed to explain these physical phenomena in terms of the strong interactions among the surface dipoles that produce …


Applications Of Decision And Utility Theory In Multi-Agent Systems, Xin Li, Leen-Kiat Soh Sep 2004

Applications Of Decision And Utility Theory In Multi-Agent Systems, Xin Li, Leen-Kiat Soh

School of Computing: Technical Reports

This report reviews the applications of decision-related theories (decision theory, utility theory, probability theory, and game theory) in various aspects of multi-agent systems. In recent years, multi-agent systems (MASs) have become a highly active research area as multi-agent systems have a wide range of applications. However, most of real-world environments are very complex and of uncertainty. An agent’s knowledge about the world is rather incomplete and uncertain. The actions of the agent are non-deterministic with a range of possible outcomes. The agent may have many desires that conflict each other. The agent also needs to know about other agents and …


Dirac-Fock Energy Levels And Transition Probabilities For Oxygen-Like Fe Xix, V. Jonauskas, F. P. Keenan, M. E. Foord, R. F. Heeter, S. J. Rose, Gary J. Ferland, R. Kisielius, Peter A. M. Van Hoof, P. H. Norrington Sep 2004

Dirac-Fock Energy Levels And Transition Probabilities For Oxygen-Like Fe Xix, V. Jonauskas, F. P. Keenan, M. E. Foord, R. F. Heeter, S. J. Rose, Gary J. Ferland, R. Kisielius, Peter A. M. Van Hoof, P. H. Norrington

Physics and Astronomy Faculty Publications

Multiconfigurational Dirac-Fock calculations are reported for 656 energy levels and the 214 840 electric dipole (E1), electric quadrupole (E2) and magnetic dipole (M1) transition probabilities in oxygen-like FeXIX. The spectroscopic notations as well as the total transition probabilities from each energy level are provided. Good agreement is found with data compiled by NIST.


Redefining The Empirical Zz Ceti Instability Strip, Anjum S. Mukadam, Ted Von Hippel, Et Al. Sep 2004

Redefining The Empirical Zz Ceti Instability Strip, Anjum S. Mukadam, Ted Von Hippel, Et Al.

Publications

We use the new ZZ Ceti stars (hydrogen-atmosphere white dwarf variables; DAVs) discovered within the Sloan Digital Sky Survey (Mukadam et al. 2004) to redefine the empirical ZZ Ceti instability strip. This is the first time since the discovery of white dwarf variables in 1968 that we have a homogeneous set of spectra acquired using the same instrument on the same telescope, and with consistent data reductions, for a statistically significant sample of ZZ Ceti stars. The homogeneity of the spectra reduces the scatter in the spectroscopic temperatures, and we find a narrow instability strip of width ~950 K, from …


Reconstruction Of Partially Conductive Cracks Using Boundary Data, David Mccune, Janine Haugh Sep 2004

Reconstruction Of Partially Conductive Cracks Using Boundary Data, David Mccune, Janine Haugh

Mathematical Sciences Technical Reports (MSTR)

This paper develops an algorithm for finding one or more non-insulated, pair-wise disjoint, linear cracks in a two dimensional region using boundary measurements.


Homology Over Local Homomorphisms, Luchezar L. Avramov, Srikanth Iyengar, Claudia Miller Sep 2004

Homology Over Local Homomorphisms, Luchezar L. Avramov, Srikanth Iyengar, Claudia Miller

Mathematics - All Scholarship

The notions of Betti numbers and of Bass numbers of a finite module N over a local ring R are extended to modules that are only assumed to be finite over S, for some local homomorphism phi: R -> S. Various techniques are developed to study the new invariants and to establish their basic properties. In several cases they are computed in closed form. Applications go in several directions. One is to identify new classes of finite R-modules whose classical Betti numbers or Bass numbers have extremal growth. Another is to transfer ring theoretical properties between R and S in …


Use Of Fecal Glucocorticoid Metabolite Measures In Conservation Biology Research: Considerations For Application And Interpretation, Joshua J. Millspaugh, Brian E. Washburn Sep 2004

Use Of Fecal Glucocorticoid Metabolite Measures In Conservation Biology Research: Considerations For Application And Interpretation, Joshua J. Millspaugh, Brian E. Washburn

United States Department of Agriculture Wildlife Services: Staff Publications

Fecal glucocorticoid metabolite analyses are increasingly being used by a variety of scientists (e.g., conservation biologists, animal scientists) to examine glucocorticoid (i.e., stress hormone) secretion in domestic and wild vertebrates. Adrenocortical activity (i.e., stress response) is of interest to conservation biologists because stress can alter animal behavior, reduce resistance to disease, and affect population performance. The noninvasiveness of fecal-based assessments is attractive, particularly when studying endangered species, because samples can often be obtained without disturbing the animal. Despite such advantages, many confounding factors inhibit the utility of this technique in addressing conservation problems. In particular, interpretation of fecal glucocorticoid metabolite …


Increasing Acceptance And Efficacy Of Zinc Phosphide Rodenticide Baits Via Modification Of The Carbohydrate Profile, J. J. Johnston, D. L. Nolte, B. A. Kimball, K. R. Perry, J. C. Hurley Sep 2004

Increasing Acceptance And Efficacy Of Zinc Phosphide Rodenticide Baits Via Modification Of The Carbohydrate Profile, J. J. Johnston, D. L. Nolte, B. A. Kimball, K. R. Perry, J. C. Hurley

United States Department of Agriculture Wildlife Services: Staff Publications

Toxicant coated grain-based baits are widely used to control rodent pests throughout the world, but where alternative food sources are available, bait acceptance and efficacy are often less than optimal. In an attempt to develop baiting strategies to increasebait acceptance and efficacy of zinc phosphide-coated baits, a sugar-enhanced rolled oat based zinc phosphide bait was evaluated. With pre-baiting, 100 and 60% mortality was achieved for California and Belding’s ground squirrels, respectively. A series of two choice tests with a variety of potential bait matrices indicated that rolled oats was a desirable base matrix for both species but the lecithin sticker …


Interoperability And The Need For Intelligent Software: A Historical Perspective, Jens G. Pohl Sep 2004

Interoperability And The Need For Intelligent Software: A Historical Perspective, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

With the objective of defining the interoperability theme of this year’s conference it is the purpose of this paper1 to trace the evolution of intelligent software from data-centric applications that essentially encapsulate their data environment to ontology-based applications with automated reasoning capabilities. The author draws a distinction between human intelligence and component capabilities within a more general definition of intelligence; - a kind of intelligence that can be embedded in computer software. The primary vehicle in the quest for intelligent software has been the gradual recognition of the central role played by data and information, rather than the logic …


Proceedings Of The 2004 Onr Decision-Support Workshop Series: Interoperability, Collaborative Agent Design Research Center Sep 2004

Proceedings Of The 2004 Onr Decision-Support Workshop Series: Interoperability, Collaborative Agent Design Research Center

Collaborative Agent Design (CAD) Research Center

In August of 1998 the Collaborative Agent Design Research Center (CADRC) of the California Polytechnic State University in San Luis Obispo (Cal Poly), approached Dr. Phillip Abraham of the Office of Naval Research (ONR) with the proposal for an annual workshop focusing on emerging concepts in decision-support systems for military applications. The proposal was considered timely by the ONR Logistics Program Office for at least two reasons. First, rapid advances in information systems technology over the past decade had produced distributed collaborative computer-assistance capabilities with profound potential for providing meaningful support to military decision makers. Indeed, some systems based on …


Education In The Environment Partnership, Public Lands Institute Sep 2004

Education In The Environment Partnership, Public Lands Institute

Presentations (PLI Education)

  • Update on Oliver Ranch
  • Update on Forever Earth
  • Update on WOW on the Water


Influence Of Lithophysae Geometry And Distribution On Mechanical Properties Of Topopah Spring Tuff, Mohammad Shahidul Islam, Justin Fenton, Moses Karakouzian, Jaime Gonzalez, Amy J. Smiecinski, Raymond E. Keeler Sep 2004

Influence Of Lithophysae Geometry And Distribution On Mechanical Properties Of Topopah Spring Tuff, Mohammad Shahidul Islam, Justin Fenton, Moses Karakouzian, Jaime Gonzalez, Amy J. Smiecinski, Raymond E. Keeler

Publications (YM)

The current Site Recommendation study for the proposed high level nuclear waste repository at Yucca Mountain locates the repository emplacement drifts approximately 81% within the lower lithophysal unit of the Topopah Springs Formation (Tptpll), 4% within the upper lithophysal unit of the Topopah Springs Formation (Tptpul), and roughly 15% within the middle, non-lithophysal unit (Tptpmn) of the same formation. A major geomechanical issue facing the Yucca Mountain Project is to understand the thermomechanical behavior of lithophysal tuff, which comprises roughly 85% of the repository host rock.


Simulations Of Resonant Alfvén Waves Generated By Artificial Hf Heating Of The Auroral Ionosphere, D Pokhotelov, W Lotko, A V. Streltsov Sep 2004

Simulations Of Resonant Alfvén Waves Generated By Artificial Hf Heating Of The Auroral Ionosphere, D Pokhotelov, W Lotko, A V. Streltsov

Dartmouth Scholarship

Numerical two-dimensional two-fluid MHD sim- ulations of dynamic magnetosphere-ionosphere (MI) cou- pling have been performed to model the effects imposed on the auroral ionosphere by a powerful HF radio wave trans- mitter. The simulations demonstrate that modifications of the ionospheric plasma temperature and recombination due to artificial heating may trigger the ionospheric feedback in- stability when the coupled MI system is close to the state of marginal stability. The linear dispersion analysis of MI coupling has been performed to find the favorable conditions for marginal stability of the system. The development of the ionospheric feedback instability leads to the generation …


Exclusive Electroproduction Of J/Ψ Mesons At-Hera, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, L. Rinaldi Sep 2004

Exclusive Electroproduction Of J/Ψ Mesons At-Hera, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, L. Rinaldi

Faculty Publications

The exclusive electroproduction of J/ψ mesons, ep→epJ/ψ, has been studied with the ZEUS detector at HERA for virtualities of the exchanged photon in the ranges 0.15


Halide Recognition Through Diagnostic “Anion–Π” Interactions: Molecular Complexes Of CL−, Br−, And I− With Olefinic And Aromatic Π Receptors, Yaroslav S. Rosokha, Sergey V. Lindeman, Sergiy V. Rosokha, Jay K. Kochi Sep 2004

Halide Recognition Through Diagnostic “Anion–Π” Interactions: Molecular Complexes Of CL−, Br−, And I− With Olefinic And Aromatic Π Receptors, Yaroslav S. Rosokha, Sergey V. Lindeman, Sergiy V. Rosokha, Jay K. Kochi

Chemistry Faculty Research and Publications

Intense colorations and new charge-transfer absorption bands are observed upon addition of a halide (Cl−, Br−, I−) to neutral organic π acceptors with electron-deficient olefinic and aromatic centers. These phenomena results from noncovalent anion–π interactions (shown schematically), which were confirmed by X-ray crystallography.


Non-Destructive Testing Of Thermal Resistances For A Single Inclusion In A 2-Dimensional Domain, Nicholas Christian, Mathew A. Johnson Sep 2004

Non-Destructive Testing Of Thermal Resistances For A Single Inclusion In A 2-Dimensional Domain, Nicholas Christian, Mathew A. Johnson

Mathematical Sciences Technical Reports (MSTR)

In this paper we examine the inverse problem of determining the amount of corrosion/disbonding which has occurred on the boundary of a single circular (or nearly circular) inclusion D in a two dimensional domain W using Cauchy data for the steady-state heat equation. We develop an algorithm for reconsructing a function which qunatifies the level of corrosion/disbonding at each point in ¶W. We also address the issue of well-posedness and develop a simple regularization scheme. Then we provide several numerical examples. We shall show a simple procedure for recovering the center of D assuming that the boundary of W and …


Lattice Supersymmetry Via Twisting, Simon Catterall Sep 2004

Lattice Supersymmetry Via Twisting, Simon Catterall

Physics - All Scholarship

We describe how the usual supercharges of extended supersymmetry may be {\it twisted} to produce a BRST-like supercharge Q. The usual supersymmetry algebra is then replaced by a twisted algebra and the action of the twisted theory is shown to be generically Q-exact. In flat space the twisting procedure can be regarded as a change of variables carrying no physical significance. However, the twisted theories can often be transferred to the lattice while preserving the twisted supersymmetry. As an example we construct a lattice version of the two-dimensional supersymmetric sigma model


Estimating A Survival Distribution With Current Status Data And High-Dimensional Covariates, Mark J. Van Der Laan, Aad Van Der Vaart Sep 2004

Estimating A Survival Distribution With Current Status Data And High-Dimensional Covariates, Mark J. Van Der Laan, Aad Van Der Vaart

U.C. Berkeley Division of Biostatistics Working Paper Series

We consider the inverse problem of estimating a survival distribution when the survival times are only observed to be in one of the intervals of a random bisection of the time axis. We are particularly interested in the case that high-dimensional and/or time-dependent covariates are available, and/or the survival events and censoring times are only conditionally independent given the covariate process. The method of estimation consists of regularizing the survival distribution by taking the primitive function or smoothing, estimating the regularized parameter by using estimating equations, and finally recovering an estimator for the parameter of interest.


Estimation Of Treatment Effects In Randomized Trials With Noncompliance And A Dichotomous Outcome , Mark J. Van Der Laan, Alan E. Hubbard, Nicholas P. Jewell Sep 2004

Estimation Of Treatment Effects In Randomized Trials With Noncompliance And A Dichotomous Outcome , Mark J. Van Der Laan, Alan E. Hubbard, Nicholas P. Jewell

U.C. Berkeley Division of Biostatistics Working Paper Series

We propose a class of estimators of the treatment effect on a dichotomous outcome among the treated subjects within covariate and treatment arm strata in randomized trials with non-compliance. Recent articles by Vansteelandt and Goethebeur (2003) and Robins and Rotnitzky (2004) have presented consistent and asymptotically linear estimators of a causal odds ratio, which rely, beyond correct specification of a model for the causal odds ratio, on a correctly specified model for a potentially high dimensional nuisance parameter. In this article we propose consistent, asymptotically linear and locally efficient estimators of a causal relative risk and a new parameter -- …


Spin Mass Of An Electron Liquid, Zhixin Qian, Giovanni Vignale, D C. Marinescu Sep 2004

Spin Mass Of An Electron Liquid, Zhixin Qian, Giovanni Vignale, D C. Marinescu

Publications

We show that in order to calculate correctly the spin current carried by a quasiparticle in an electron liquid one must use an effective ‘‘spin mass’’ ms that is larger than both the band mass mb, which determines the charge current, and the quasiparticle effective mass m, which determines the heat capacity. We present two independent estimates of the spin mass enhancement, ms=mb, in two- and three-dimensional electron liquids, based on (i) previously calculated values of the Landau parameters and (ii) a recent theory of the dynamical local field factor in the spin channel. Both methods yield a significant spin …


Gaining Ground Information Database, John R. Nolon, Jessica A. Bacher, Susan Moritz Sep 2004

Gaining Ground Information Database, John R. Nolon, Jessica A. Bacher, Susan Moritz

Yale School of the Environment Publications Series

A Report on a New Internet Research Library of Innovative Land Use Laws, Regulations, and Practices


Subgradients Of Distance Functions At Out-Of-Set Points, Boris S. Mordukhovich, Nguyen Mau Nam Sep 2004

Subgradients Of Distance Functions At Out-Of-Set Points, Boris S. Mordukhovich, Nguyen Mau Nam

Mathematics Research Reports

This paper deals with the classical distance function to closed sets and its extension to the case of set-valued mappings. It has been well recognized that the distance functions play a crucial role in many aspects of variational analysis, optimization, and their applications. One of the most remarkable properties of even the classical distance function is its intrinsic nonsmoothness, which requires the usage of generalized differential constructions for its study and applications. In this paper we present new results in theser directions using mostly the generalized differential constructions introduced earlier by the first author, as well as their recent modifications. …


On Time Series Analysis Of Public Health And Biomedical Data, Scott L. Zeger, Rafael A. Irizarry, Roger D. Peng Sep 2004

On Time Series Analysis Of Public Health And Biomedical Data, Scott L. Zeger, Rafael A. Irizarry, Roger D. Peng

Johns Hopkins University, Dept. of Biostatistics Working Papers

A time series is a sequence of observations made over time. Examples in public health include daily ozone concentrations, weekly admissions to an emergency department or annual expenditures on health care in the United States. Time series models are used to describe the dependence of the response at each time on predictor variables including covariates and possibly previous values in the series. Time series methods are necessary to account for the correlation among repeated responses over time. This paper gives an overview of time series ideas and methods used in public health research.