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2009

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Articles 241 - 270 of 6337

Full-Text Articles in Physical Sciences and Mathematics

Converse Comparison Theorems For Backward Doubly Stochastic Differential Equations, Mohamed El Otmani, Naoual Mrhardy Dec 2009

Converse Comparison Theorems For Backward Doubly Stochastic Differential Equations, Mohamed El Otmani, Naoual Mrhardy

Communications on Stochastic Analysis

No abstract provided.


Spatial Instability Of Electrically Driven Jets With Finite Conductivity And Under Constant Or Variable Applied Field, Saulo Orizaga, Daniel N. Riahi Dec 2009

Spatial Instability Of Electrically Driven Jets With Finite Conductivity And Under Constant Or Variable Applied Field, Saulo Orizaga, Daniel N. Riahi

School of Mathematical & Statistical Sciences Faculty Publications

We investigate the problem of spatial instability of electrically driven viscous jets with finite electrical conductivity and in the presence of either a constant or a variable applied electric field. A mathematical model, which is developed and used for the spatially growing disturbances in electrically driven jet flows, leads to a lengthy equation for the unknown growth rate and frequency of the disturbances. This equation is solved numerically using Newton’s method. For neutral temporal stability boundary, we find, in particular, two new spatial modes of instability under certain conditions. One of these modes is enhanced by the strength Ω of …


On The Testing And Estimation Of High-Dimensional Covariance Matrices, Thomas Fisher Dec 2009

On The Testing And Estimation Of High-Dimensional Covariance Matrices, Thomas Fisher

All Dissertations

Many applications of modern science involve a large number of parameters. In
many cases, the number of parameters, p, exceeds the number of observations,
N. Classical multivariate statistics are based on the assumption that the
number of parameters is fixed and the number of observations is large. Many of
the classical techniques perform poorly, or are degenerate, in high-dimensional
situations.
In this work, we discuss and develop statistical methods for inference of
data in which the number of parameters exceeds the number of observations.
Specifically we look at the problems of hypothesis testing regarding and the
estimation of the covariance …


Exploring Formation And Distribution Of Halonitromethanes In Drinking Waters, Jia Hu Dec 2009

Exploring Formation And Distribution Of Halonitromethanes In Drinking Waters, Jia Hu

All Dissertations

ABSTRACT
Nine halonitromethanes (HNMs) were among the more than fifty unregulated high-priority disinfection by-products (DBPs) that were monitored for and detected in drinking waters in a 2000-2002 nationwide occurrence study funded by the US Environmental Protection Agency (USEPA). The toxicology studies conducted in recent years have shown that HNMs are one of the most cytotoxic and genotoxic classes among the emerging DBPs, with orders of magnitude higher cytotoxicity and genotoxicity than any of the regulated organic DBPs. Furthermore, brominated HNMs were found to be more toxic than their chlorinated analogs, with dibromonitromethane being the most cyto- and genotoxic. Today, our …


Tactical Analysis Of Attack In Physical And Digital Security Incidents:Towards A Model Of Asymmetry, Atif Ahmad Dec 2009

Tactical Analysis Of Attack In Physical And Digital Security Incidents:Towards A Model Of Asymmetry, Atif Ahmad

Australian Information Warfare and Security Conference

Asymmetric warfare is frequently described as a conflict where ‘weaker’ parties aim to offset their relatively inadequate resources by using particular strategies and tactics to their advantage. This research-in-progress paper develops a concept model of asymmetric warfare that represents the leverage available to the ‘weaker’ party over the ‘stronger’ party simply because the former is attacking rather than defending. Points of leverage include choice of timing, location, method of attack, best use of limited resources and time to prepare. The resulting concept model is used to discuss generic defensive strategies that can be applied by ‘stronger’ parties in the physical …


Ascent Of Asymmetric Risk In Information Security: An Initial Evaluation., Tobias Ruighaver, Matthew Warren, Atif Ahmad Dec 2009

Ascent Of Asymmetric Risk In Information Security: An Initial Evaluation., Tobias Ruighaver, Matthew Warren, Atif Ahmad

Australian Information Warfare and Security Conference

Dramatic changes in the information security risk landscape over several decades have not yet been matched by similar changes in organizational information security, which is still mainly based on a mindset that security is achieved through extensive preventive controls. As a result, maintenance cost of information security is increasing rapidly, but this increased expenditure has not really made an attack more difficult. The opposite seems to be true, information security attacks have become easier to perpetrate and appear more like information warfare tactics. At the same time, the damage caused by a successful attack has increased significantly and may sometimes …


Information Security Disclosure: A Case Study, I Rosewall, M J. Warren Dec 2009

Information Security Disclosure: A Case Study, I Rosewall, M J. Warren

Australian Information Security Management Conference

New social networking systems such as Facebook are an ever evolving and developing means of social interaction, which is not only being used to disseminate information to family, friends and colleagues but as a way of meeting and interacting with "strangers" through the advent of a large number of social applications. This paper will focus upon the impact of Generation F - the Facebook Generation and their attitudes to security. The paper will be based around discussing the findings of a major UK case study and the implications that this has. The case study identifies 51 recommendations to improve the …


Strong Authentication For Web Services Using Smartcards, D S. Stienne, Nathan Clarke, Paul Reynolds Dec 2009

Strong Authentication For Web Services Using Smartcards, D S. Stienne, Nathan Clarke, Paul Reynolds

Australian Information Security Management Conference

The popularity of the Internet and the variety of services it provides has been immense. Unfortunately, many of these services require the user to register and subsequently login to the system in order to access them. This has resulted in the user having to remember a multitude of username and password combinations in order to use the service securely. However, literature has clearly demonstrated this is not an effective approach, as users will frequently choose simple passwords, write them down, share them or use the same password for multiple systems. This paper proposes a novel concept where Internet users authenticate …


Security Issues Challenging Facebook, S Leitch, M Warren Dec 2009

Security Issues Challenging Facebook, S Leitch, M Warren

Australian Information Security Management Conference

The advancement in Internet and bandwidth capability has resulted in a number of new applications to be developed; many of these newer applications are described as being Web 2. A Web 2 application such as Facebook has allowed people around the world to interact together. One of the interesting aspects of Facebook is the use of third parties applications and the interactions that this allows.Not surprisingly, the problems that exist in the real world such as theft, fraud, vandalism also exist in online Web 2 environments. This paper explores and categorises several security issues within the Facebook environment. It contributes …


Improving An Organisations Existing Information Technology Policy To Increase Security, Shane Talbot, Andrew Woodward Dec 2009

Improving An Organisations Existing Information Technology Policy To Increase Security, Shane Talbot, Andrew Woodward

Australian Information Security Management Conference

A security policy which includes the appropriate phases of implementation, enforcement, auditing and review is vital to protecting an organisations information security. This paper examined the information security policy of a government organisation in response to a number of perceived shortcomings. The specific issues identified relating to the organisations security policy as a result of this investigation were as follows: a culture of ignoring policies, minimal awareness of policies, minimal policy enforcement, policy updating and review ad hoc at best, policy framework, lengthy policy development and approval process, no compliance program, no formal non-compliance reporting and an apparent inconsistent enforcement …


Roost Selection By Rafinesque's Big-Eared Bats, Corynorhinus Rafinesquii, In Congaree National Park - A Multiscale Approach, Jessica Lucas Dec 2009

Roost Selection By Rafinesque's Big-Eared Bats, Corynorhinus Rafinesquii, In Congaree National Park - A Multiscale Approach, Jessica Lucas

All Theses

Little is known about natural roost selection of Rafinesque's big-eared bats, Corynorhinus rafinesquii , throughout their range. The objectives of this study were to determine roost use and selection of big-eared bats in the Upper Coastal Plain of South Carolina at multiple spatial scales and test whether roost use and selection differed between maternity colonies and solitary individuals. The study was conducted May-August 2006 and 2007 in Congaree National Park which contains extensive areas of old-growth bottomland forest. Roost trees were located via tree searches and radio-telemetry and I used univariate tests and multiple logistic regression to compare tree, stand, …


The Distribution And Reproductive Success Of The Western Snowy Plover Along The Oregon Coast - 2009, David J. Lauten, Kathleen J. Castelein, J. Daniel Farrar, Hendrik G. Herlyn, Eleanor P. Gaines Dec 2009

The Distribution And Reproductive Success Of The Western Snowy Plover Along The Oregon Coast - 2009, David J. Lauten, Kathleen J. Castelein, J. Daniel Farrar, Hendrik G. Herlyn, Eleanor P. Gaines

Institute for Natural Resources Publications

From 3 April – 23 September 2009 we monitored the distribution, abundance and productivity of the federally Threatened Western Snowy Plover (Charadrius alexandrinus nivosus) along the Oregon coast. From north to south, we surveyed and monitored plover activity at Sutton Beach, Siltcoos River estuary, the Dunes Overlook, North Tahkenitch Creek, Tenmile Creek, Coos Bay North Spit, Bandon Beach, New River, and Floras Lake. Our objectives for the Oregon coastal population in 2009 were to: 1) estimate the size of the adult Snowy Plover population, 2) locate plover nests, 3) continue selective use of mini-exclosures (MEs) to protect nests …


Empirical Mode Decomposition Operator For Dewowing Gpr Data, Bradley M. Battista, Adrian Addison, Camelia C. Knapp Dec 2009

Empirical Mode Decomposition Operator For Dewowing Gpr Data, Bradley M. Battista, Adrian Addison, Camelia C. Knapp

Faculty Publications

Signal processing tools available to ground penetrating radar data used for shallow subsurface imaging and hydrogeophysical parameter estimation are significantly handled using the same tools available to seismic reflection data. Overall, the same tools produce interpretable images from both data types, but particular noise (wow noise) in electromagnetic data must be removed before stable and accurate quantitative results can be produced. Wow noise is an inherent, nonlinear electromagnetic interference and a significant component of GPR data. Further, the nonlinear and non-stationary nature of wow noise provides a strong argument for preprocessing radar traces with time-domain operators. Time-domain operators designed for …


The Ecology Of The Peaks Of Otter Salamander (Plethodon Hubrichti) In Sympatry With The Eastern Red-Backed Salamander (Plethodon Cinereus), Norman Reichenbach, Andrew Kniowski Dec 2009

The Ecology Of The Peaks Of Otter Salamander (Plethodon Hubrichti) In Sympatry With The Eastern Red-Backed Salamander (Plethodon Cinereus), Norman Reichenbach, Andrew Kniowski

Faculty Publications and Presentations

The Peaks of Otter Salamander, Plethodon hubrichti, is found along a 19 km length of the Blue Ridge Mountains, Virginia, USA, often in sympatry with the Eastern Red-backed Salamander, P. cinereus. In a sympatric area of Bedford County, Virginia, we conducted a mark-recapture study on a 10 × 10 m site. Surface densities of salamanders increased as the number of days without precipitation prior to a collection event increased. This suggests vertical movements in response to surface moisture. When salamanders returned to the surface after rain, individuals appeared to “shuffle” between rocks and likely, leaf litter. That is, we were …


Nonlinear Evolution Of Baryon Acoustic Oscillations From Improved Perturbation Theory In Real And Redshift Spaces, Atsushi Taruya, Takahiro Nishimichi, Shun Saito, Takashi Hiramatsu Dec 2009

Nonlinear Evolution Of Baryon Acoustic Oscillations From Improved Perturbation Theory In Real And Redshift Spaces, Atsushi Taruya, Takahiro Nishimichi, Shun Saito, Takashi Hiramatsu

Physics Faculty Research & Creative Works

We study the nonlinear evolution of baryon acoustic oscillations in the matter power spectrum and correlation function from the improved perturbation theory (PT). Based on the framework of renormalized PT, which provides a nonperturbative way to treat the gravitational clustering of large-scale structure, we apply the closure approximation that truncates the infinite series of loop contributions at one-loop order, and obtain a closed set of integral equations for power spectrum and nonlinear propagator. The resultant integral expressions are basically equivalent to those previously derived in the form of evolution equations, and they keep important nonperturbative properties which can dramatically improve …


Systematic Analysis Of Double-Ionization Dynamics Based On Four-Body Dalitz Plots, Daniel Fischer, Michael Schulz, Katharina R. Schneider, Marcelo F. Ciappina, Tom Kirchner, Aditya H. Kelkar, S. Hagman, Manfred Grieser, Kai Uwe Kuhnel, Robert Moshammer, Joachim Hermann Ullrich Dec 2009

Systematic Analysis Of Double-Ionization Dynamics Based On Four-Body Dalitz Plots, Daniel Fischer, Michael Schulz, Katharina R. Schneider, Marcelo F. Ciappina, Tom Kirchner, Aditya H. Kelkar, S. Hagman, Manfred Grieser, Kai Uwe Kuhnel, Robert Moshammer, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

We report on an experimental and theoretical systematic study of double ionization of helium by ion impact in terms of four-particle Dalitz plots. Several collision systems covering abroad range of perturbation parameters η (projectile charge to speed ratio) were investigated. With increasing η we observe a systematic trend from features, characteristic to correlated double-ionization mechanisms, to signatures of higher-order processes not requiring electron-electron correlations [the mechanism called "two-step-two projectile-electron interaction" (TS-2)]. The data for the largest η can qualitatively be amazingly well described by a simple model only including the TS-2 mechanism.


The White Dwarfs Within 20 Parsecs Of The Sun: Kinematics And Statistics, Edward M. Sion, Jay B. Holberg, Terry D. Oswalt, George P. Mccook, Richard Wasatonic Dec 2009

The White Dwarfs Within 20 Parsecs Of The Sun: Kinematics And Statistics, Edward M. Sion, Jay B. Holberg, Terry D. Oswalt, George P. Mccook, Richard Wasatonic

Aerospace, Physics, and Space Science Faculty Publications

We present the kinematical properties, distribution of spectroscopic subtypes, and stellar population subcomponents of the white dwarfs within 20 pc of the Sun. We find no convincing evidence of halo white dwarfs in the total 20 pc sample of 129 white dwarfs nor is there convincing evidence of genuine thick disk subcomponent members within 20 parsecs. Virtually, the entire 20 pc sample likely belongs to the thin disk. The total DA to non-DA ratio of the 20 pc sample is 1.6, a manifestation of deepening envelope convection which transforms DA stars with sufficiently thin H surface layers into non-DAs. The …


Thin Film Integrated Capacitors With Sputtered-Anodized Niobium Pentoxide Dielectric For Decoupling Applications, Susan Jacob Dec 2009

Thin Film Integrated Capacitors With Sputtered-Anodized Niobium Pentoxide Dielectric For Decoupling Applications, Susan Jacob

Graduate Theses and Dissertations

Electronics system miniaturization is a major driver for high-k materials. High-k materials in capacitors allow for high capacitance, enabling system miniaturization. Ta2O5 (k~24) has been the dominant high-k material in the electronic industry for decoupling capacitors, filter capacitors, etc. In order to facilitate further system miniaturization, this project has investigated thin film integrated capacitors with Nb2O5 dielectric. Nb2O5 has k~41 and is a potential candidate for replacing Ta2O5. But, the presence of suboxides (NbO2 and NbO) in the dielectric deteriorates the electrical properties (leakage current, thermal instability of capacitance, etc.). Also, the high oxygen solubility of niobium results in oxygen …


An Isomorphism Theorem For Graphs, Laura Culp Dec 2009

An Isomorphism Theorem For Graphs, Laura Culp

Theses and Dissertations

In the 1970’s, L. Lovász proved that two graphs G and H are isomorphic if and only if for every graph X , the number of homomorphisms from X → G equals the number of homomorphisms from X → H . He used this result to deduce cancellation properties of the direct product of graphs. We develop a result analogous to Lovász’s theorem, but in the class of graphs without loops and with weak homomorphisms. We apply it prove a general cancellation property for the strong product of graphs.


Rainsford Island Shoreline Evolution Study (Rises), Christopher V. Maio Dec 2009

Rainsford Island Shoreline Evolution Study (Rises), Christopher V. Maio

Graduate Masters Theses

RISES conducted a shoreline change study in order to accurately map, quantify, and predict trends in shoreline evolution on Rainsford Island occurring from 1890-2008. It employed geographic information systems (GIS) and analytical statistical techniques to identify coastal hazard zones vulnerable to coastal erosion, rising sea-levels, and storm surges. The 11-acre Rainsford Island, located in Boston Harbor, Massachusetts, consists of two eroded drumlins connected by a low-lying spit. Settled by Europeans in 1636, the Island was later used as the Harbor’s main quarantine station. Previous archeological surveys have identified numerous historically sensitive sites dating to before the Revolutionary War period, including …


The R Journal (December 2009) 1(2): Complete Issue, The R Foundation Dec 2009

The R Journal (December 2009) 1(2): Complete Issue, The R Foundation

The R Journal

Contributed Research Articles

Aspects of the Social Organization and Trajectory of the R Project, John Fox

Party on! Carolin Strobl, Torsten Hothorn and Achim Zeileis

ConvergenceConcepts: An R Package to Investigate Various Modes of Convergence, Pierre Lafaye de Micheaux and Benoit Liquet

asympTest: A Simple R Package for Classical Parametric Statistical Tests and Confidence Intervals in Large Samples, J.-F. Coeurjolly, R. Drouilhet, P. Lafaye de Micheaux and J.-F. Robineau

copas: An R package for Fitting the Copas Selection Model, J. Carpenter, G. Rücker and G. Schwarzer

Transitioning to R: Replicating SAS, Stata, and SUDAAN Analysis Techniques in Health Policy Data, …


A Contrast Pattern Based Clustering Quality Index For Categorical Data, Qingbao Liu, Guozhu Dong Dec 2009

A Contrast Pattern Based Clustering Quality Index For Categorical Data, Qingbao Liu, Guozhu Dong

Kno.e.sis Publications

Since clustering is unsupervised and highly explorative, clustering validation (i.e. assessing the quality of clustering solutions) has been an important and long standing research problem. Existing validity measures have significant shortcomings. This paper proposes a novel contrast pattern based clustering quality index (CPCQ) for categorical data, by utilizing the quality and diversity of the contrast patterns (CPs) which contrast the clusters in clusterings. High quality CPs can characterize clusters and discriminate them against each other. Experiments show that the CPCQ index (1) can recognize that expert-determined classes are the best clusters for many datasets from the UCI repository; (2) does …


Bio-Inspired Node Localization In Wireless Sensor Networks, Raghavendra V. Kulkarni, Ganesh K. Venayagamoorthy, Maggie X. Cheng Dec 2009

Bio-Inspired Node Localization In Wireless Sensor Networks, Raghavendra V. Kulkarni, Ganesh K. Venayagamoorthy, Maggie X. Cheng

Electrical and Computer Engineering Faculty Research & Creative Works

Many applications of wireless sensor networks (WSNs) require location information of the randomly deployed nodes. a common solution to the localization problem is to deploy a few special beacon nodes having location awareness, which help the ordinary nodes to localize. in this approach, non-beacon nodes estimate their locations using noisy distance measurements from three or more non-collinear beacons they can receive signals from. in this paper, the ranging-Based localization task is formulated as a multidimensional optimization problem, and addressed using bio-inspired algorithms, exploiting their quick convergence to quality solutions. an investigation on distributed iterative localization is presented in this paper. …


Geometry Of Control-Affine Systems, Jeanne N. Clelland, Christopher G. Moseley, George R. Wilkens Dec 2009

Geometry Of Control-Affine Systems, Jeanne N. Clelland, Christopher G. Moseley, George R. Wilkens

University Faculty Publications and Creative Works

Motivated by control-affine systems in optimal control theory, we introduce the notion of a point-affine distribution on a manifold X - i.e., an affine distribution F together with a distinguished vector field contained in F. We compute local invariants for point-affine distributions of constant type when dim(X) = n, rank(F) = n - 1, and when dim(X) = 3, rank(F) = 1. Unlike linear distributions, which are characterized by integer- valued invariants - namely, the rank and growth vector - when dim(X) ≤ 4, we find local invariants depending on arbitrary functions even for rank 1 point-affine distributions on manifolds …


Lead Optimization Of Cox-2 Inhibitor Nimesulide Analogs To Overcome Aromatase Inhibitor Resistance In Breast Cancer Cells, Bin Su, Shiuan Chen Dec 2009

Lead Optimization Of Cox-2 Inhibitor Nimesulide Analogs To Overcome Aromatase Inhibitor Resistance In Breast Cancer Cells, Bin Su, Shiuan Chen

Chemistry Faculty Publications

A series of COX-2 selective inhibitor nimesulide derivatives were synthesized. Their anti-cell proliferation activities were evaluated with a long-term estrogen deprived MCF-7aro (LTEDaro) breast cancer cell line, which is the biological model of aromatase inhibitor resistance for hormone-dependent breast cancer. Compared to nimesulide which inhibited LTEDaro cell proliferation with an IC50 at 170.30 μM, several new compounds showed IC50 close to 1.0 μM.


An Animation Framework For Improving The Comprehension Of Tinyos Programs, Sravanthi Dandamudi Dec 2009

An Animation Framework For Improving The Comprehension Of Tinyos Programs, Sravanthi Dandamudi

All Theses

To meet the increasing demand for monitoring of the physical world, there has been an increase in the development of wireless sensor network applications. The TinyOS platform has emerged as a de facto standard for developing these applications. The platform offers a number of advantages, with its support for concurrency, power-efficient operation, and resource-constrained hardware chief among them. However, the benefits come at a price. Even without the TinyOS platform, the inherent parallel and distributed nature of these applications makes it difficult for developers to reason about program behavior. Further, the TinyOS programming model adopts
asynchronous, split-phase execution semantics. Developers …


Thermochromic Absorption And Photoluminescence In [Pt(Ppy)(Μ-Ph2pz)]2, Aaron A. Rachford, Felix N. Castellano Dec 2009

Thermochromic Absorption And Photoluminescence In [Pt(Ppy)(Μ-Ph2pz)]2, Aaron A. Rachford, Felix N. Castellano

Chemistry Faculty Publications

The temperature effects on the spectral properties and photophysics of a new d(8)-d(8) dinuclear Pt-II chromophore, [Pt(ppy)(mu-Ph(2)pz)](2) (ppy is 2-phenylpyridine and Ph(2)pz is 3,5-diphenylpyrazolate), have been investigated. The thermochromic shifts are tentatively ascribed to intramolecular sigma interactions between the two pseudocofacial d(Z2) orbitals. Substantial emission profile changes occur in the solid state, solution, and doped polymer films.


Modeling The Fluorescence Of Protein-Embedded Tryptophans With Ab Initio Multiconfigurational Quantum Chemistry: The Limiting Cases Of Parvalbumin And Monellin, Sara Pistolesi, Adalgisa Sinicropi, Rebecca Pogni, Riccardo Basosi, Nicolas Ferre, Massimo Olivucci Dec 2009

Modeling The Fluorescence Of Protein-Embedded Tryptophans With Ab Initio Multiconfigurational Quantum Chemistry: The Limiting Cases Of Parvalbumin And Monellin, Sara Pistolesi, Adalgisa Sinicropi, Rebecca Pogni, Riccardo Basosi, Nicolas Ferre, Massimo Olivucci

Chemistry Faculty Publications

We show that a quantum-mechanics/molecular-mechanics strategy based on ab initio (i.e., first principle) multiconfigurational perturbation theory can reproduce the spectral properties of a tryptophan residue embedded in the contrasting hydrophobic and hydrophilic environments of parvalbumin and monellin, respectively. We show that the observed absorption and emission energies can be reproduced with a less than 3 kcal mol(-1) error. The analysis of the computed emission energies based on a protein disassembly scheme and protein electrostatic potential mapping allows for a detailed understanding of the factors modulating the tryptophan emission. It is shown that for rnonellin, where the tryptophan is exposed to …


Notes From The Director, The Mcnair Team Dec 2009

Notes From The Director, The Mcnair Team

McNair Scholars Research Journal

No abstract provided.


Acknowledgements, The Mcnair Team Dec 2009

Acknowledgements, The Mcnair Team

McNair Scholars Research Journal

No abstract provided.