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2003

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Articles 1381 - 1410 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Using Low Level Linear Memory Management For Type-Preserving Mark-Sweep Garbage Collector, Edward Wei May 2003

Using Low Level Linear Memory Management For Type-Preserving Mark-Sweep Garbage Collector, Edward Wei

Dartmouth College Undergraduate Theses

Efficient low-level systems such as garbage collectors need more control over memory than safe high-level languages usually provide. Due to this constraint, garbage collectors are typically written in unsafe languages such as C. A collector of this form usually resides as a trusted primitive runtime service outside the model of the programming language. The type safety of these languages depends on the assumption that the garbage collector will not violate any typing invariants. However, no realistic systems provide proof of this assumption. A garbage collector written in a strongly typed language can guarantee not only the safety of the garbage …

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Combinatorial Techniques For Digital Image Charecterization And Retrieval:Algorithms,Architectures,And Applications., Arijit Bishnu Dr. May 2003

Combinatorial Techniques For Digital Image Charecterization And Retrieval:Algorithms,Architectures,And Applications., Arijit Bishnu Dr.

Doctoral Theses

Interest in digital images stems mostly from its application to various areas of computer vision [33, 57] and pattern recognition [145). Problems include robotic vision and con- trol, geographic and topographic map matching, target recognition, space applications, character recognition, scene analysis, fingerprint and face recognition, etc. Lately, with the advent of content-based image retrieval (CBIR) and proliferation of the Internet, digital imaging applications are in vogue now than ever before. In almost all the cases, the data size is enormously large, and at the same time, fast on-line as well as real- time computation is needed. For example, in fingerprint …

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Supervised Detection Of Regulatory Motifs In Dna Sequences, Sunduz Keles, Mark J. Van Der Laan, Sandrine Dudoit, Biao Xing, Michael B. Eisen May 2003

Supervised Detection Of Regulatory Motifs In Dna Sequences, Sunduz Keles, Mark J. Van Der Laan, Sandrine Dudoit, Biao Xing, Michael B. Eisen

U.C. Berkeley Division of Biostatistics Working Paper Series

Identification of transcription factor binding sites (regulatory motifs) is a major interest in contemporary biology. We propose a new likelihood based method, COMODE, for identifying structural motifs in DNA sequences. Commonly used methods (e.g. MEME, Gibbs sampler) model binding sites as families of sequences described by a position weight matrix (PWM) and identify PWMs that maximize the likelihood of observed sequence data under a simple multinomial mixture model. This model assumes that the positions of the PWM correspond to independent multinomial distributions with four cell probabilities. We address supervising the search for DNA binding sites using the information derived from …

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Knot Intervals And Multi-Degree Splines, Thomas W. Sederberg, Jianmin Zheng, Xiaowen Song May 2003

Knot Intervals And Multi-Degree Splines, Thomas W. Sederberg, Jianmin Zheng, Xiaowen Song

Faculty Publications

This paper studies the merits of using knot interval notation for B-spline curves, and presents formulae in terms of knot intervals for common B-spline operations such as knot insertion, differentiation, and degree elevation. Using knot interval notation, the paper introduces MD-splines, which are B-spline-like curves that are comprised of polynomial segments of various degrees (MD stands for \multi-degree"). MD-splines are a generalization of B-spline curves in that if all curve segments in an MD-spline have the same degree, it reduces to a B-spline curve. The paper focuses on MD-splines of degree 1, 2, and 3, as well as degree 1 …

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Lower Miocene To Present Stratigraphy Of The Equatorial Pacific Sediment Bulge And Carbonate Dissolution Anomalies, Neil C. Mitchell, Mitchell W. Lyle, Marie B. Knappenberger, Lee M. Liberty May 2003

Lower Miocene To Present Stratigraphy Of The Equatorial Pacific Sediment Bulge And Carbonate Dissolution Anomalies, Neil C. Mitchell, Mitchell W. Lyle, Marie B. Knappenberger, Lee M. Liberty

CGISS Publications and Presentations

The bulge is a 600-m-thick regional deposit of pelagic sediment accumulated around the equator. Its stratigraphy reflects a number of factors: how accumulation rates have varied over time, how accumulation has been spatially focused around the equator, how much carbonate dissolution and reworking or nondeposition by bottom currents have occurred, and how much the deposits have been translated northward by motion of the Pacific tectonic plate on which they have accumulated. In order to fully explore the effects of these processes, a spatially continuous stratigraphic database is desirable, as existing cores provide information at only discrete points, and they tend …

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An Analysis Of Convergence Properties Of The Border Gateway Protocol Using Discrete Event Simulation, Brian J. Premore May 2003

An Analysis Of Convergence Properties Of The Border Gateway Protocol Using Discrete Event Simulation, Brian J. Premore

Dartmouth College Ph.D Dissertations

The Internet is an enormous internetwork formed by connecting tens of thousands of independently managed computer networks. Though the Internet has no central authority and is highly heterogeneous, a universally adopted addressing scheme---defined by the Internet Protocol (IP)---makes interaction between the individual networks possible. Complementing IP is the Border Gateway Protocol (BGP), which facilitates communication between parts of the internetwork by determining paths by which data can get from one network to any other. Just as IP is used ubiquitously as an addressing scheme, BGP is used ubiquitously for the purpose of network-to-network routing. Because BGP is universal, its well-being …

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Improved Confidence Intervals For The Sensitivity At A Fixed Level Of Specificity Of A Continuous-Scale Diagnostic Test, Xiao-Hua Zhou, Gengsheng Qin May 2003

Improved Confidence Intervals For The Sensitivity At A Fixed Level Of Specificity Of A Continuous-Scale Diagnostic Test, Xiao-Hua Zhou, Gengsheng Qin

UW Biostatistics Working Paper Series

For a continuous-scale test, it is an interest to construct a confidence interval for the sensitivity of the diagnostic test at the cut-off that yields a predetermined level of its specificity (eg. 80%, 90%, or 95%). IN this paper we proposed two new intervals for the sensitivity of a continuous-scale diagnostic test at a fixed level of specificity. We then conducted simulation studies to compare the relative performance of these two intervals with the best existing BCa bootstrap interval, proposed by Platt et al. (2000). Our simulation results showed that the newly proposed intervals are better than the BCa bootstrap …

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Unlv Transmutation Research Program Proposal Year Iii: Design And Evaluation Of Processes For Fuel Fabrication, Georg F. Mauer May 2003

Unlv Transmutation Research Program Proposal Year Iii: Design And Evaluation Of Processes For Fuel Fabrication, Georg F. Mauer

Fuels Campaign (TRP)

The objective of this project is the design and evaluation of manufacturing processes for transmuter fuel fabrication. The large-scale deployment of remote fabrication and refabrication processes will be required for all transmutation scenarios. Current program emphasis is on a five-year effort to determine the feasibility of transmutation as a technology to limit the need for repository storage of spent commercial fuel. The evaluation of the fabrication processes will create a decision support data base to document design, operations, and costs. Fabrication processes required for different fuel types differ in terms of equipment types, throughput, and cost. Differential cost Implications of …

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Synthesis Of Tin Oxide Nanocrystalline Phases Via Use Of Tin (Ii) Halide Precursors, Hongmei Deng, Frank K. Lamelas, Jeanne Hossenlopp May 2003

Synthesis Of Tin Oxide Nanocrystalline Phases Via Use Of Tin (Ii) Halide Precursors, Hongmei Deng, Frank K. Lamelas, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

Nanocrystalline tin oxides are synthesized via precipitation from heated solutions as well as from a novel above-solution vapor deposition route that occurs at low temperatures and atmospheric pressure. Crystalline phases are characterized via powder X-ray diffraction. Samples precipitated from reactions of SnCl2 are found to exist primarily as mixtures of tetragonal SnO and tetragonal SnO2 or tetragonal SnO2 and tin(II) oxyhydroxide (Sn6O4- (OH)4), depending on reaction conditions. A mixed tin(II)/tin(IV) sample is shown to produce a rarely observed form of the intermediate oxide Sn3O4 upon annealing in air at 600 °C. SnBr2 exclusively forms tetragonal SnO2 via precipitation. Variation in …

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Spacecraft Charging Research, Eric Crapo May 2003

Spacecraft Charging Research, Eric Crapo

Senior Theses and Projects

No abstract provided.

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Effects Of The Sound Speed Of Quintessence On The Microwave Background And Large Scale Structure, Simon Dedeo, R. R. Caldwell, Paul J. Steinhardt May 2003

Effects Of The Sound Speed Of Quintessence On The Microwave Background And Large Scale Structure, Simon Dedeo, R. R. Caldwell, Paul J. Steinhardt

Dartmouth Scholarship

We consider how quintessence models in which the sound speed differs from the speed of light and varies with time affect the cosmic microwave background and the fluctuation power spectrum. Significant modifications occur on length scales related to the Hubble radius during epochs in which the sound speed is near zero and the quintessence contributes a non-negligible fraction of the total energy density. For the microwave background, we find that the usual enhancement of the lowest multipole moments by the integrated Sachs-Wolfe effect can be modified, resulting in suppression or bumps instead. Also, the sound speed can produce oscillations and …

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Bootstrap Confidence Intervals For Medical Costs With Censored Observations, Hongyu Jiang, Xiao-Hua Zhou May 2003

Bootstrap Confidence Intervals For Medical Costs With Censored Observations, Hongyu Jiang, Xiao-Hua Zhou

UW Biostatistics Working Paper Series

Medical costs data with administratively censored observations often arise in cost-effectiveness studies of treatments for life threatening diseases. Mean of medical costs incurred from the start of a treatment till death or certain timepoint after the implementation of treatment is frequently of interest. In many situations, due to the skewed nature of the cost distribution and non-uniform rate of cost accumulation over time, the currently available normal approximation confidence interval has poor coverage accuracy. In this paper, we proposed a bootstrap confidence interval for the mean of medical costs with censored observations. In simulation studies, we showed that the proposed …

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Semantic Web Process Lifecycle: Role Of Semantics In Annotation, Discovery, Composition And Orchestration, Amit P. Sheth May 2003

Semantic Web Process Lifecycle: Role Of Semantics In Annotation, Discovery, Composition And Orchestration, Amit P. Sheth

Kno.e.sis Publications

No abstract provided.

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Is There A Cost Tipping Point For E-Journals?, Gordon C. Tibbitts May 2003

Is There A Cost Tipping Point For E-Journals?, Gordon C. Tibbitts

Gordon C. Tibbitts III

The above-inflation cost increases of scholarly publication and the reduction in library budgets may foster a new era of access. Emerging paradigms including open access, open choice, and "author paid" are only the beginning of the possibilities as the industry approaches what some call a "tipping point."

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New Intervals For The Difference Between Two Independent Binomial Proportions, Xiao-Hua Zhou, Min Tsao, Gengsheng Qin May 2003

New Intervals For The Difference Between Two Independent Binomial Proportions, Xiao-Hua Zhou, Min Tsao, Gengsheng Qin

UW Biostatistics Working Paper Series

In this paper we gave an Edgeworth expansion for the studentized difference of two binomial proportions. We then proposed two new intervals by correcting the skewness in the Edgeworth expansion in a direct and an indirect way. Such the bias-correct confidence intervals are easy to compute, and their coverage probabilities converge to the nominal level at a rate of O(n-½), where n is the size of the combined samples. Our simulation results suggest tat in finite samples the new interval based on the indirect method have the similar performance to the two best existing intervals in terms of coverage accuracy …

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Longevity Of A Woodhouse's Toad, Richard M. Engeman, Melvin A. Engeman May 2003

Longevity Of A Woodhouse's Toad, Richard M. Engeman, Melvin A. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

We follow up a report on a male Woodhouse's toad (Bufo woodhousii) that had been observed since 1978 (Engeman RM, Engeman EM. 1996. Longevity of Woodhouse's toad in Colorado. Northwestern Naturalist 77:23). The toad had found its way into, and remained in, a basement window-well of a brick home in an unincorporated western suburb of Denver, Colorado. This property has recently changed hands, and access for future monitoring of the toad's survival is uncertain. Thus, we report its longevity as of 2002.

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Compression Tolerant Dct Based Image Hash, C. Kailasanathan, R. Safavi-Naini, P. Ogunbona May 2003

Compression Tolerant Dct Based Image Hash, C. Kailasanathan, R. Safavi-Naini, P. Ogunbona

Faculty of Informatics - Papers (Archive)

With the advent of Internet image authentication has become a central part of research in security. Since JPEG has recommended discrete cosine transform as one of the steps in image compression systems, a hash function which utilizes discrete cosine decomposition is desirable. In this paper, we propose a discrete cosine based hash function which distinguishes acceptable level of compression from image processing modifications such as Median filtering, Gaussian noise addition, and FMLR attack. To increase manipulation detection, we optimize the number of AC coefficients needed in smoothing.

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Anthropogenic Influences On Avian Life, Past And Present, Within The Adirondack Park, Melodee A. Decoteau May 2003

Anthropogenic Influences On Avian Life, Past And Present, Within The Adirondack Park, Melodee A. Decoteau

MALS Final Projects, 1995-2019

In the northeastern comer of New York over the last 10,000 years, avian life developed a complex network of niches within the varied ecosystems produced by the retreat of the last glacier. When humans began to dominate the area, beginning around two hundred years ago, avian diversity was compromised. The past and present anthropogenic influences have increasingly intensified the stresses on avian life in the park. If avian diversity is to be preserved, human factions must work together to decrease that stress. The establishment of the Adirondack Park and hunting seasons as well as restrictions on pesticide use have directly …

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A Noise Filtering Method Using Neural Networks, Tony R. Martinez, Xinchuan Zeng May 2003

A Noise Filtering Method Using Neural Networks, Tony R. Martinez, Xinchuan Zeng

Faculty Publications

During the data collecting and labeling process it is possible for noise to be introduced into a data set. As a result, the quality of the data set degrades and experiments and inferences derived from the data set become less reliable. In this paper we present an algorithm, called ANR (automatic noise reduction), as a filtering mechanism to identify and remove noisy data items whose classes have been mislabeled. The underlying mechanism behind ANR is based on a framework of multi-layer artificial neural networks. ANR assigns each data item a soft class label in the form of a class probability …

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Simplifying Ocr Neural Networks With Oracle Learning, Tony R. Martinez, Joshua Menke May 2003

Simplifying Ocr Neural Networks With Oracle Learning, Tony R. Martinez, Joshua Menke

Faculty Publications

Often the best model to solve a real world problem is relatively complex. The following presents oracle learning, a method using a larger model as an oracle to train a smaller model on unlabeled data in order to obtain (1) a simpler acceptable model and (2) improved results over standard training methods on a similarly sized smaller model. In particular, this paper looks at oracle learning as applied to multi-layer perceptrons trained using standard backpropagation. For optical character recognition, oracle learning results in an 11.40% average decrease in error over direct training while maintaining 98.95% of the initial oracle accuracy.

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Authoritative Citation Knn Learning With Noisy Training Datasets, Leen-Kiat Soh, Joseph Bernadt May 2003

Authoritative Citation Knn Learning With Noisy Training Datasets, Leen-Kiat Soh, Joseph Bernadt

CSE Technical Reports

In this paper, we investigate the effectiveness of Citation K-Nearest Neighbors (KNN) learning with noisy training datasets. We devise an authority measure associated with each training instance that changes based on the outcome of Citation KNN classification. The authority is increased when a citer’s classification had been right; and vice versa. We show that by modifying only these authority measures, the classification accuracy of Citation KNN improves significantly in a variety of datasets with different noise levels. We also identify the general characteristics of a dataset that affect the improvement percentages. We conclude that the new algorithm is able to …

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Evaluating The Effects Of Enhanced Processivity And Metal Ions On Translesion Dna Replication Catalyzed By The Bacteriophage T4 Dna Polymerase, Edmunds Z. Reineks, Anthony J. Berdis May 2003

Evaluating The Effects Of Enhanced Processivity And Metal Ions On Translesion Dna Replication Catalyzed By The Bacteriophage T4 Dna Polymerase, Edmunds Z. Reineks, Anthony J. Berdis

Chemistry Faculty Publications

The fidelity of DNA replication is achieved in a multiplicative process encompassing nucleobase selection and insertion, removal of misinserted nucleotides by exonuclease activity, and enzyme dissociation from primer/templates that are misaligned due to mispairing. In this study, we have evaluated the effect of altering these kinetic processes on the dynamics of translesion DNA replication using the bacteriophage T4 replication apparatus as a model system. The effect of enhancing the processivity of the T4 DNA polymerase, gp43, on translesion DNA replication was evaluated using a defined in vitro assay system. While the T4 replicase (gp43 in complex with gp45) can perform …

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Linear Models For Microarray Data Analysis: Hidden Similarities And Differences, M. Kathleen Kerr May 2003

Linear Models For Microarray Data Analysis: Hidden Similarities And Differences, M. Kathleen Kerr

UW Biostatistics Working Paper Series

In the past several years many linear models have been proposed for analyzing two-color microarray data. As presented in the literature, many of these models appear dramatically different. However, many of these models are reformulations of the same basic approach to analyzing microarray data. This paper demonstrates the equivalence of some of these models. Attention is directed at choices in microarray data analysis that have a larger impact on the results than the choice of linear model.

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Compressed Data Structures For Recursive Flow Classification, Edward W. Spitznagel May 2003

Compressed Data Structures For Recursive Flow Classification, Edward W. Spitznagel

All Computer Science and Engineering Research

High-speed packet classification is crucial to the implementation of several advanced network services and protocols; many QoS implementations, active networking platforms, and security devices (such as firewalls and intrusion-detection systems) require it. But performing classification on multiple fields, at the speed of modern networks, is known to be a difficult problem. The Recursive Flow Classification (RFC) algorithm described by Gupta and McKeown performs classification very quickly, but can require excessive storage when using thousands of rules. This paper studies a compressed representation for the tables used in RFC, trading some memory accesses for space. The compression’s efficiency can be improved …

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Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823 For Transmutation Applications, Ajit K. Roy, Brendan O'Toole May 2003

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823 For Transmutation Applications, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The purpose of this project is to evaluate the elevated temperature tensile properties of Alloy EP-823, a leading target material for accelerator-driven waste transmutation applications. This alloy has been proven to be an excellent structural material to contain the lead-bismuth-eutectic (LBE) nuclear coolant needed for fast spectrum operations. However, very little data exist in the open literature on the tensile properties of this alloy. The selection of Alloy EP-823 as the test material in the proposed task is based on the recommendation of our collaborator at the Los Alamos National Laboratory (LANL). The test material will be thermally treated prior …

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Development Of A Systems Engineering Model Of The Chemical Separations Process, Yitung Chen, Darrell Pepper, Randy Clarksean May 2003

Development Of A Systems Engineering Model Of The Chemical Separations Process, Yitung Chen, Darrell Pepper, Randy Clarksean

Separations Campaign (TRP)

Two activities are proposed: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model will be continuously focusing on the integrated approach to the analysis of the materials separations associated with the TRP Program. A second portion of the project will streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral to the systems engineering model. …

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Highly Oriented Nonepitaxially Grown L10 Fept Films, M.L. Yan, Nathan D. Powers, David J. Sellmyer May 2003

Highly Oriented Nonepitaxially Grown L10 Fept Films, M.L. Yan, Nathan D. Powers, David J. Sellmyer

David Sellmyer Publications

A method of preparing nonepitaxially grown, highly textured L10 FePt thin films is described. A nearly perfect (001) texture was obtained by direct deposition of FePt films on Corning 7059 glass substrates and subsequent rapid thermal annealing. The ordering and orientation of the L10-phase FePt grains were controlled by the initial as-deposited film structure, and also by the annealing process. Magnetic measurements reveal large perpendicular anisotropy for these (001) textured films. The substrates and processes used for nonepitaxial growth of L10 ordered FePt films are much more compatible with practical applications than those …

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Studies Of Magnetic Properties Of The Stabilizing Layer For Synthetic Antiferromagnetically Coupled Media, Z.S. Shan, L. Bitman, S.S. Malhotra, D. Stafford, B. Bian, G. Bertero May 2003

Studies Of Magnetic Properties Of The Stabilizing Layer For Synthetic Antiferromagnetically Coupled Media, Z.S. Shan, L. Bitman, S.S. Malhotra, D. Stafford, B. Bian, G. Bertero

David Sellmyer Publications

The effects of the stabilizing layer thickness and its temperature dependence on the magnetic properties were investigated experimentally. These results were used to analyze the magnetic structure of the thin stabilizing layer and its effect on the coupling strength, which is valuable for improving the design of synthetic antiferromagnetically coupled media.

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Structure And Magnetic Properties Of Sputtered Hard/Soft Multilayer Magnets, W. Liu, Z.D. Zhang, J. Ping Liu, B.Z. Cui, X.K. Sun, J. Zhou, David J. Sellmyer May 2003

Structure And Magnetic Properties Of Sputtered Hard/Soft Multilayer Magnets, W. Liu, Z.D. Zhang, J. Ping Liu, B.Z. Cui, X.K. Sun, J. Zhou, David J. Sellmyer

David Sellmyer Publications

The films with HM = (Pr,Dy)(Fe,Co,Nb,B) 5.5 and SM=Fe, FeCo were prepared by sputtering and subsequent heat treatment. The coercivity of Ti-buffered (Pr,Dy)(Fe,Co,Nb,B) 5.5 single-layer film with 320 nm thickness is as large as 18.8 kOe at room temperature. X-ray diffraction results reveal that the Pr2Fe14B-type phase is randomly oriented in almost all the multilayer films. For the multilayers of Ti(30 nm)/[HM(16 nm)Fe(x nm)]×20/Ti(30 nm)/Si(substrate), the remanence increases and the coercivity decreases with the addition of Fe content, in comparison with the results of the single-layer film and the maximum energy product of 14.8 MGOe is …

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Exchange Through Nonmagnetic Insulating Matrix, Ralph Skomski, Arti Kashyap, Y. Quiang, David J. Sellmyer May 2003

Exchange Through Nonmagnetic Insulating Matrix, Ralph Skomski, Arti Kashyap, Y. Quiang, David J. Sellmyer

David Sellmyer Publications

Exchange interactions between hard-magnetic particles in a nonmagnetic matrix are investigated by model calculations. A Landau–Ginzburg approach is developed to describe the net exchange interactions between spheres of arbitrary diameters. Introducing cylindrical coordinates and integrating over the surfaces of the adjacent spheres yields an exchange coupling which decreases with a decay length depending on interatomic exchange, intra-atomic exchange, and temperature. Typically, the decay length does not exceed a few interatomic distances. The decay is exponential but also contains a prefactor depending on the surface curvature of the grains. It increases with decreasing curvature, but this dependence is only a small …

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