Physical Sciences and Mathematics Commons^™

Method For Identifying Individuals, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A method and system for identifying a subject comprises obtaining a digitised recording of an electrocardiogram measurement of the subject to be identified, the digitised recording being a cyclic waveform having a peak amplitude. The digitised recording is normalised to reduce variations due to physiological effects, and the normalised recording is processed to determine a feature vector in the frequency domain. The distance between the determined feature vector and a predetermined feature vector is measured to identify the subject.

On The Use Of Randomness In Computing To Perform Intelligent Tasks, Ryan Scott Regensburger

Theses and Dissertations

The study of Artificial Intelligence attempts to simulate the processes of human intelligence in a set of computable algorithms. The purpose of Random Algorithms in this field is to provide a best-guess approach at identifying the unknown. In this thesis, research shows that random algorithms are able to break down many intelligent processes into a set of solvable problems. For example, solving puzzles and playing games involve the same estimating ability shown in standard problems such as the Coupon Collector problem or the Monty Hall problem. This thesis shows Random Algorithmic applications in two overlapping categories of intelligent behavior: Pattern …

Tracking The Sea-Level Signature Of The 8.2 Ka Cooling Event: New Constraints From The Mississippi Delta, Torbjörn E. Törnqvist, Scott J. Bick, Juan L. Gonzalez, Klaas Van Der Borg, Arie F. M. De Jong

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The ever increasing need for accurate predictions of global environmental change under greenhouse conditions has sparked immense interest in an abrupt, century‐scale cooling around 8200 years ago, with a focal point in the North Atlantic and with hemispheric teleconnections. Despite considerable progress in the unraveling of this striking feature, including a conceivable driving mechanism (rapid drainage of proglacial Lake Agassiz/Ojibway and a resulting reduced strength of North Atlantic thermohaline circulation), several key questions remain unanswered. One salient aspect concerns the total amount of freshwater released during this catastrophic event, likely echoed by a near‐instantaneous eustatic sea‐level rise. So far, no …

Modeling The Spread And Prevention Of Malicious Mobile Code Via Simulation Cs-2004-15, Christopher Brian Shirey

Theses and Dissertations

Malicious mobile code causes billions of dollars every year in damages, and that cost keeps increasing. Traditional signature-based anti-virus software is a reactive solution that can not detect fast spreading malicious code quickly enough to prevent widespread infection. If we hope to prevent widespread infection of future malicious mobile code, new prevention techniques must be developed that either stop a new infection completely, or at least limit the spread until signature-based anti-virus software can be updated. Simulators exist that model the spread of malicious mobile code, but none currently exists that can efficiently model host-based and network-based spread prevention techniques …

Analysis Of Hostile Network Reconnaissance To Anticipate And Mitigate Network Attacks, Luis Angel Rivera

Theses and Dissertations

Network security systems today such as current intrusion detection systems, intrusion prevention systems and firewalls are good at reacting to attacks as they occur or shortly after they occur. Current security systems lack the ability to identify and detect the activity that usually precedes an attack. This activity is known as network reconnaissance. In this thesis we have developed a technique that can assist current security systems to detect hostile network reconnaissance to anticipate and mitigate network attacks.

On Security Notions For Steganalysis, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim, Jongin Lim

Research Collection School Of Computing and Information Systems

There have been some achievements in steganalysis recently. Many people have been making strides in steganalysis. They have approached steganalysis from different angles; from information theory to complexity theory. Anderson gave a possibility that there is a provable secure steganographic system, but there had not been complexity theoretical approaches for years. In 2002, Katzenbeisser and Petitcolas defined the conditional security of steganography and gave a possibility for a practical, provable secure steganography for the first time, and Hopper et al. introduced a provable secure steganographic algorithm in the sense of complexity theory. Chang et al. also tried to define the …

Recommender Systems For Multimedia Libraries: An Evaluation Of Different Models For Datamining Usage Data, Raquel Oliveira Araujo

Computer Science Theses & Dissertations

Many recommender systems exist today to help users deal with the large growth in the amount of information available in the Internet. Most of these recommender systems use collaborative filtering or content-based techniques to present new material that would be of interest to a user. While these methods have proven to be effective, they have not been designed specifically for multimedia collections. In this study we present a new method to find recommendations that is not dependent on traditional Information Retrieval (IR) methods and compare it to algorithms that do rely on traditional IR methods. We evaluated these algorithms using …

Chemical And Toxicological Characterization Of The Upper York River, Virginia The Mattaponi And Pamunkey Rivers, Morris H. Roberts Jr., Mark Richards, Peter F. Delisle

Reports

This study describes the most extensive effort to characterize the chemistry, toxicology and community of the sediments of the Mattaponi and Pamunkey Rivers. This was accomplished using a study design modified to expand the number of stations occupied by reducing the cost of analyses by compositing replicate samples collected from each study site rather than performing toxicity tests on these samples individually. In previous studies, the variability in field replicate samples was equivalent to the variability in laboratory replicates. This design has long been used to analyze samples for various chemical contaminants as a cost savings endeavor. More ....

Automatic Model Structuring From Text Using Biomedical Ontology, Joshi R., Li X., Ramachandaran S., Tze-Yun Leong

Research Collection School Of Computing and Information Systems

Bayesian Networks and Influence Diagrams are effective methods for structuring clinical problems. Constructing a relevant structure without the numerical probabilities in itself is a challenging task. In addition, due to the rapid rate of innovations and new findings in the biomedical domain, constructing a relevant graphical model becomes even more challenging. Building a model structure from text with minimum intervention from domain experts and minimum training examples has always been a challenge for the researchers. In the biomedical domain, numerous advances have been made which may make this dream a possibility now. We are currently trying to build a general …

Analysis Of Reflected Spectral Signatures And Detection Of Geophysical Disturbance Using Hyperspectral Imagery, Forrest Mccoy Hoffman

Masters Theses

Geophysical disturbances resulting from human activities often have significant
consequences for plants and animals, and even for entire ecosystems.Disturbances resulting from petroleum exploration and production activities can have long term impacts on soils, watersheds, rivers and lakes, vegetation, wildlife, and humans. These anthropogenic disturbances are frequently the result of hydrocarbon (oil) or produced water (brine) spills. Brine is usually produced simultaneously with oil or gas. The ability to detect brine spills with remote sensing techniques would be valuable to petroleum companies and industry regulators. The objectives of this research were to 1) determine if brine spills could be detected spectroscopically, …

Joint Size Estimation Using Joint Traces On Borehole Walls, Christopher James Heiny

Masters Theses

One approach to characterizing subsurface joint populations is to assume
surface joint patterns are representative of joints at depth. Yet, many times, either the analogous surface joints are unexposed, or absent because surface rocks did not experience the same deformation history. The alternative of direct subsurface characterization has been limited by joints not being resolvable in seismic data and borehole data not yielding fracture size. The present approach uses the subsurface geometry of joint/borehole intersections to estimate mean joint size (mean joint length and width) and aspect ratio (joint length to width ratio), and presents a new method for determining …

Low Energy Excitations In Spin Clusters And Molecular Solids, Jason Thomas Haraldsen

Masters Theses

This thesis investigates low energy magnetic and vibrational excitations in molecular solids. Analytical and numerical studies of these two types of excitations, both in idealized systems and in more complicated models that are thought to capture the relevant physics of several materials. The materials considered include molecular magnets and layered organic superconductors and semiconductors. Our results include exact expressions for certain magnetic observables, neutron scattering structure factors for small spin 1/2 clusters, studies of the molecular dynamics of Fe₈Br₈ molecular magnet, the e®ects of symmetry breaking in (DT-TTF)₂Au(mnt)₂ spin ladder candidate, and the importance …

Crown Reductions And Decompositions: Theoretical Results And Practical Methods, William Henry Suters, Iii

Masters Theses

Two kernelization schemes for the vertex cover problem, an NP-hard problem in graph theory, are compared. The first, crown reduction, is based on the identification of a graph structure called a crown and is relatively new while the second, LP-kernelization has been used for some time. A proof of the crown reduction algorithm is presented, the algorithm is implemented and theorems are proven concerning its performance. Experiments are conducted comparing the performance of crown reduction and LP- kernelization on real world biological graphs. Next, theorems are presented that provide a logical connection between the crown structure and LP-kernelization. Finally, an …

Probabilistic Suffix Models For Windows Application Behavior Profiling: Framework And Initial Results, Geoffrey Alan Mazeroff

Masters Theses

Developing statistical/structural models of code execution behavior is of considerable practical importance. This thesis describes a framework for employing probabilistic suffix models as a means of constructing behavior profiles from code-traces of Windows XP applications. Emphasis is placed on the inference and use of probabilistic suffix trees and automata with new contributions in the area of auxiliary symbol distributions. An initial real-time classification system is discussed and preliminary results of detecting known benign and viral applications are presented.

Maximal Clique Enumeration And Related Tools For Microarray Data Analysis, Nicole E. Baldwin

Masters Theses

The purpose of this study was to investigate the utility of exact maximal clique enumeration in DNA microarray analysis, to analyze and improve upon existing exact maximal clique enumeration algorithms, and to develop new clique-based algorithms to assist in the analysis as indicated during the course of the study. As a first test, microarray data sets comprised of pre-classified human lung tissue samples were obtained through the Critical Assessment of Microarray Data Analysis (CAMDA) conference. A combination of exact maximal clique enumeration and approximate dominating set was used to attempt to classify the samples.

In another test, maximal clique enumeration …

A Framework For Downloading Wide-Area Files, Rebecca Lynn Collins

Masters Theses

The challenge of efficiently retrieving files that are broken into segments and replicated across the widearea is of prime importance to wide-area, peer-to-peer, and Grid file systems. Two different algorithms addressing this challenge have been proposed and evaluated. While both have been successful in different performance scenarios, there has been no unifying work that can view both algorithms under a single framework. In this thesis, we define such a framework, where download algorithms are defined in terms of the four dimensions that the client always controls: the number of simultaneous downloads, the degree of work replication, the failover strategy, and …

The Characterization Of Nanosized Nickel-Zinc Ferrites Synthesized Within Reverse Micelles Of Ctab/1-Hexanol/Water Microemulsion, Vuk Uskoković, Miha Drofenik, Irena Ban

Pharmacy Faculty Articles and Research

Stoichiometric nanocrystalline nickel–zinc ferrites were synthesized by a reverse micelle method following a multi-microemulsion approach. Different pH values were chosen for the alkali precipitating reaction during the synthesis of different powders. Synthesized, as-dried and subsequently calcined powders were characterized in terms of their magnetic properties. XRD analyses and specific-surface area measurements were used to determine the average particle sizes of the synthesized samples. DCS and TGA measurements were performed to reveal the phase transitions within the samples at elevated temperatures, whereas TEM was used to view and record the microstructure of the nanosized ferrite samples. A possible mechanism of the …

Discrete-Time Fractional Differentiation From Integer Derivatives, Hany Farid

Computer Science Technical Reports

Discrete-time fractional derivative filters (1-D and 2-D) are shown to be well approximated from a small set of integer derivatives. A fractional derivative of arbitrary order (and, in 2-D, of arbitrary orientation) can therefore be efficiently computed from a linear combination of integer derivatives of the underlying signal or image.

Self‐Consistent Diffusive Lifetimes Of Weibel Magnetic Fields In Gamma‐Ray Bursts, C. H. Jaroschek, H. Lesch, R. A. Treumann

Dartmouth Scholarship

Weibel filamentation in relativistic plasma shell collisions has been demonstrated as an efficient and fast mechanism for the generation of near-equipartition magnetic fields in self-consistent particle-in-cell (PIC) simulations. In generic γ-ray burst (GRB) models with kinetically dominated plasma outflow, sufficient strength and lifetime of magnetic fields are essential to validate synchrotron emission as the source of radiative outbursts. In this article we report on self-consistent PIC simulations of pair-plasma shell collisions in the highly relativistic regime with particle ensembles up to 5 × 10⁸. Energy dependence of magnetic field generation in the Weibel process is discussed, and for …

Application Of Detuned Laser Beatwave For Generation Of Few-Cycle Electromagnetic Pulses, Serguei Y. Kalmykov, Gennady Shvets

Serge Youri Kalmykov

An approach to compressing high-power laser beams in plasmas via coherent Raman sideband generation is described. The technique requires two beams: a pump and a probe detuned by a near-resonant frequency \Omega < \omega_p. The two laser beams drive a high-amplitude electron plasma wave (EPW) which modifies the refractive index of plasma so as to produce a periodic phase modulation of the incident laser with the laser beat period t_b = 2\pi / \Omega. After propagation through plasma, the original laser beam breaks into a train of chirped beatnotes (each of duration t_b). The chirp is positive (the longer-wavelength sidebands are advanced in time) when \Omega < \omega_p and negative otherwise. Finite group velocity dispersion (GVD) of radiation in plasma can compress the positively chirped beatnotes to a few-laser-cycle duration thus creating in plasma a sequence of sharp electromagnetic spikes separated in time by t_b. Driven EPW strongly couples the laser sidebands and thus reduces the effect of GVD. Compression of the chirped beatnotes can be implemented in a separate plasma of higher density, where the laser sidebands become uncoupled.

Field-And Temperature-Induced Topological Phase Transitions In Three Dimensional N-Component London Superconductor, J. Smiseth, E. Smorgrav, Egor Babaev, A. Sudbo

Egor Babaev

The phase diagram and critical properties of the $N$-component London superconductor are studied both analytically and through large-scale Monte-Carlo simulations in $d=2+1$ dimensions (components here refer to different replicas of the complex scalar field). Examples are given of physical systems to which this model is applicable. The model with different bare phase stiffnesses for each component, is a model of superconductivity which should arise out of metallic phases of light atoms under extreme pressure. A projected mixture of electronic and protonic condensates in liquid metallic hydrogen under extreme pressure is the simplest example, corresponding to N=2. These are such that …

Population Recovery And Differential Heat Shock Protein Expression For The Corals Agaricia Agaricites And A. Tenuifolia In Belize, Martha L. Robbart, Paulette M. Peckol, Stylianos P. Scordilis, H. Allen Curran, Jocelyn Brown-Saracino

Geosciences: Faculty Publications

Over recent decades, coral reefs worldwide have experienced severe sea-surface temperature (SST) anomalies. Associated with an El Niño-Southern Oscillation (ENSO) event of 1997-1998, nearly 100% mortality of the space-dominated coral Agaricia tenuifolia was reported at several shelf lagoonal sites of the Belize barrier reef system; a less abundant congener, A. agaricites, had lower mortality rates. We assessed A. agaricites and A. tenuifolia populations at coral reef ridges in the south-central sector of the Belize shelf lagoon and forereef sites to document recovery following the 1998 ENSO event and subsequent passage of Hurricane Mitch. To investigate the difference in heat …

Education In The Environment: A Hands-On Student Research And Outdoor Learning Experience: Quarterly Progress Report, Period Ending November 30, 2004, Margaret N. Rees

Reports (PLI Education)

During the past three-months, the focus of the university’s efforts has been 1) making progress on the hiring of permanent project managers for the Education in the Environment Strategy and the Forever Earth / Wonderful Outdoor World on the Water (WOW) projects; 2) completing legal review of the cooperative agreement and standard operating procedures required for the university to assume operations of the Forever Earth vessel; and 3) writing curriculum for the WOW and Forever Earth projects.

Effect Of Hydrologic Restoration On The Habitat Of The Cape Sable Seaside Sparrow, Annual Report Of 2003-2004, Michael S. Ross, Jay P. Sah, Pablo L. Ruiz, David T. Jones, Hillary Cooley, Rafael Travieso, James R. Snyder, Sara Robinson

SERC Research Reports

Following on our previous year’s work on ‘Effect of hydrologic restoration on the habitat of the Cape Sable seaside sparrow (CSSS)’, we presented first year results at the Cape Sable seaside sparrow – fire planning workshop at Everglades National Park in December 2003. Later, with almost the same set of crews as in the previous year, we started field work in the first week of January and continued till May 26, 2004. Protocols for sampling topography and vegetation in 2004 were identical to the previous year. In the early season, we completed topographic surveys along two remaining transects, B and …

Ip Algorithm Applied To Proteomics Data, Christopher Lee Green

Theses and Dissertations

Mass spectrometry has been used extensively in recent years as a valuable tool in the study of proteomics. However, the data thus produced exhibits hyper-dimensionality. Reducing the dimensionality of the data often requires the imposition of many assumptions which can be harmful to subsequent analysis. The IP algorithm is a dimension reduction algorithm, similar in purpose to latent variable analysis. It is based on the principle of maximum entropy and therefore imposes a minimum number of assumptions on the data. Partial Least Squares (PLS) is an algorithm commonly used with proteomics data from mass spectrometry in order to reduce the …

Evaluation Of Striped Bass Stocks In Virginia : Monitoring And Tagging Studies, 2004-2008 Annual Report 1 September 2003 - 31 August 2004, Philip W. Sadler, John M. Hoenig, Robert E. Harris, Bonnie G. Holliman

Reports

This report presents the results of striped bass (Marone saxatilis) tagging and monitoring activities in Virginia during the period 1 August 2003 through 31 August 2004. It includes an assessment of the biological characteristics of striped bass taken from the 2004 spring spawning run, estimates of annual survival based on annual spring tagging, and the results of the fall 2003 directed mortality study that is a collaborative effort with the Maryland Department ofNatural Resources. The information contained in this report is required by the Atlantic States Marine Fisheries Commission and is used to implement a coordinated management plan for striped …

Secure Hardware Enhanced Myproxy: A Ph.D. Thesis Proposal, John Marchesini, David Kotz

Computer Science Technical Reports

In 1976, Whitfield Diffie and Martin Hellman demonstrated how "New Directions In Cryptography" could enable secure information exchange between parties that do not share secrets. In order for public key cryptography to work in modern distributed environments, we need an infrastructure for finding and trusting other parties' public keys (i.e., a PKI). A number of useful applications become possible with PKI. While the applications differ in how they use keys (e.g., S/MIME uses the key for message encryption and signing, while client-side SSL uses the key for authentication), all applications share one assumption: users have keypairs. In previous work, we …

Pluton Zonation Unveiled By Gamma-Ray Spectrometry And Magnetic Susceptibility; A Case Study Of The Sheeprock Granite, Western, Utah, Paul D. Richardson

Theses and Dissertations

A radiometric survey of the zoned 21 Ma, A-type Sheeprock granite, western Utah, combined with measurements of magnetic susceptibility and field observations were analyzed using a geographic information system. The intrusion spans 25 square km and is roughly eliptical in shape with its long axis trending northwest. Concentration maps (composed of more than 500 survey stations) of eU, eTh, texture, magnetic susceptibility, color, and joint density help to constrain magmatic and post-magmatic processes related to its chemical and physical zonation. Uranium ranges from 3.9 to 26.9 ppm (mean 12.7) and thorium from 1.7 to 125.7 ppm (mean 45.5). Similarities in …

Attractiveness Of Brown Rice Baits To Non-Target Birds In Harvested Corn And Soybean Fields, George M. Linz, Gregory A. Knutsen, H. Jeffrey Homan, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

Brown rice is used as a bait-carrier for the avicide DRC-1339 (3-chloro-4-methyladhe) when baiting blackbirds (Icteridae). In March and April 1996 and 1997, we assessed non-target granivorous bird use of rice-baited plots placed in harvested corn and soybean fields in eastern South Dakota for 168 observation hours. In both years combined, we identified 10 and 14 granivorous species in corn and soybean fields, respectively. In 1996 (X = 0.2, SE = 0.04) and 1997 (X = 1.2, SE = 0.38), total numbers of granivores min^-1 were similar between crops (P ≥ 0.322). In 1996, bird numbers …

The Electrochemical Performance Of Modified Spinel At Elevated Temperature, Zhen-Ping Cai, Xiao-Hong Chen, Shi-Gang Lu, Ming-Xun Li, Wei-Hua Jin

Journal of Electrochemistry

The modified LiMn_2O_4 cathode materials for lithium ion batteries have been synthesized by solid-state reaction. The crystal structure and electrochemical performance of products have been investigated by SEM、XRD and electrochemical measurements. The XRD analysis indicated that all the synthesized products possess Fd3m spinel LiMn_2O_4 structure. Those modified LiMn_2O_4 materials showed improved cycling capacity over pure spinels at high temperature and room temperature.