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2004

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Articles 451 - 480 of 4447

Full-Text Articles in Physical Sciences and Mathematics

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix, Spencer M. Steinberg, Gary Cerefice, David W. Emerson Oct 2004

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix, Spencer M. Steinberg, Gary Cerefice, David W. Emerson

Separations Campaign (TRP)

The recovery of iodine released during the processing of used nuclear fuel poses a significant challenge to the transmutation of radioactive iodine. During the first two years of this program we have examined the potential of Fullerene Containing Carbon compounds (FCC) developed by KRI, and natural organic matter (NOM) as sorbents for iodine released during the reprocessing of nuclear fuel. This work involved the development of bench-scale testing of the FCC and NOM material in a simulated process off-gas environment.

Research Objectives and Goals

• Develop bench-scale experimental set-up and procedures for simulating PUREX head-end vapor phase; Develop experimental procedures …


Image Database Retrieval Using Sketched Queries, A. Chalechale, G. Naghdy, Prashan Premaratne Oct 2004

Image Database Retrieval Using Sketched Queries, A. Chalechale, G. Naghdy, Prashan Premaratne

Faculty of Informatics - Papers (Archive)

This paper presents a novel approach for sketch-based image retrieval based on low-level features. It enables the measuring of the similarity among full color multi-component images within a database (models) and simple black and white user sketched queries. It needs no cost intensive image segmentation. Strong edges of the model image and morphologically thinned version of the query image are used for image abstraction. Angular-radial decomposition of pixels in the abstract images is used to extract new compact and affine invariant features. Comparative results, employing an art database (ArT BANK), show significant improvement in average normalized modified retrieval rank (ANMRR) …


De-Cumulant Based Approaches For Convolutive Blind Source Separation, T. Mei, Jiangtao Xi, Joe F. Chicharo, F. Yin Oct 2004

De-Cumulant Based Approaches For Convolutive Blind Source Separation, T. Mei, Jiangtao Xi, Joe F. Chicharo, F. Yin

Faculty of Informatics - Papers (Archive)

This paper studies the blind separation of signal sources (BSS) based on the approach of de-cumulant. It considers the cases where independent signal sources are mixed through convolutive mixing system with unity autochannel frequency responses and causal cross-channel FIR filters. Firstly, it tries to show that the de-cumulant is sufficient for separation. Secondly, novel algorithms are developed based on zero-forcing of cross-cumulant pairs. These algorithms are developed in the time-domain and so there is not the frequency permutation ambiguity problem usually suffered by most of the frequency-domain algorithms. Simulation results are presented to support the validity of the proposed algorithms.


Hybrid Atomistic-Coarse-Grained Treatment Of Thin-Film Lubrication. Ii, Z.-B. Wu, Dennis J. Diestler, Xiao Cheng Zeng Oct 2004

Hybrid Atomistic-Coarse-Grained Treatment Of Thin-Film Lubrication. Ii, Z.-B. Wu, Dennis J. Diestler, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

A new hybrid atomistic-coarse-grained (HACG) treatment of reversible processes in multiple-scale systems involving fluid-solid interfaces was tested through isothermal-isobaric Monte Carlo simulations of the quasistatic shearing of a model two-dimensional lubricated contact comprising two planar Lennard-Jones solid substrates that sandwich a softer Lennard-Jones film. Shear-stress profiles (plots of shear stress Tyx versus lateral displacement of the substrates) obtained by the HACG technique, which combines an atomistic description of the interfacial region with a continuum description of regions well removed from the interface, are compared with “exact” profiles (obtained by treating the whole system at the atomic scale) for a …


Melting Points And Thermal Expansivities Of Proton-Disordered Hexagonal Ice With Several Model Potentials, Yuji Koyama, Hideki Tanaka, Guangtu Gao, Xiao Cheng Zeng Oct 2004

Melting Points And Thermal Expansivities Of Proton-Disordered Hexagonal Ice With Several Model Potentials, Yuji Koyama, Hideki Tanaka, Guangtu Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

A method of free energy calculation is proposed, which enables to cover a wide range of pressure and temperature. The free energies of proton-disordered hexagonal ice (ice Ih) and liquid water are calculated for the TIP4P [J. Chem. Phys. 79, 926 (1983)] model and the TIP5P @J. Chem. Phys. 112, 8910 (2000) model. From the calculated free energy curves, we determine the melting point of the proton-disordered hexagonal ice at 0.1 MPa (atmospheric pressure), 50 MPa, 100 MPa, and 200 MPa. The melting temperatures at atmospheric pressure for the TIP4P ice and the TIP5P ice are found to be about …


Computing The M = 1 Diocotron Frequency Via An Equilibrium Calculation In Non-Neutral Plasmas, Ross L. Spencer Oct 2004

Computing The M = 1 Diocotron Frequency Via An Equilibrium Calculation In Non-Neutral Plasmas, Ross L. Spencer

Faculty Publications

The m = 1 diocotron mode in non-neutral plasmas has long been thought of as a shifted equilibrium, and its frequency has been approximately calculated in this way by Fine and Driscoll [Phys. Plasmas 5, 601 (1998)]. This article shows that this idea can be coupled with a standard axisymmetric equilibrium calculation on a grid to calculate the frequency of this mode to very high precision including both finite-length and thermal effects, provided that the Debye length is small enough. As the Debye length begins to approach the plasma size not only does the shifted equilibrium calculation fail to predict …


Direct Photon Cross Section With Conversions At Cdf, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Oct 2004

Direct Photon Cross Section With Conversions At Cdf, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present a measurement of the isolated direct photon cross section in pp̅ collisions at √s =1.8 TeV and |η|0→γγ and η→γγ events from the data we use a new background subtraction technique which takes advantage of the tracking information available in a photon conversion event. We find that the shape of the cross section as a function of photon pT is poorly described by next-to-leading-order QCD predictions, but agrees with previous CDF measurements.


Composing A Well-Typed Region, Chris Hawblitzel, Heng Huang, Lea Wittie Oct 2004

Composing A Well-Typed Region, Chris Hawblitzel, Heng Huang, Lea Wittie

Computer Science Technical Reports

Efficient low-level systems need more control over memory than safe high-level languages usually provide. In particular, safe languages usually prohibit explicit deallocation, in order to prevent dangling pointers. Regions provide one safe deallocation mechanism; indeed, many region calculi have appeared recently, each with its own set of operations and often complex rules. This paper encodes regions from lower-level typed primitives (linear memory, coercions, and delayed types), so that programmers can design their own region operations and rules.


Disk Based Model Checking, Tonglaga Bao Oct 2004

Disk Based Model Checking, Tonglaga Bao

Theses and Dissertations

Disk based model checking does not receive much attention in the model checking field becasue of its costly time overhead. In this thesis, we present a new disk based algorithm that can get close to or faster verification speed than a RAM based algorithm that has enough memory to complete its verification. This algorithm also outperforms Stern and Dill's original disk based algorithm. The algorithm partitions the state space to several files, and swaps files into and out of memory during verification. Compared with the RAM only algorithm, the new algoritm reduces hash table insertion time by reducing the cost …


Data Adaptive Estimation Of The Treatment Specific Mean, Yue Wang, Oliver Bembom, Mark J. Van Der Laan Oct 2004

Data Adaptive Estimation Of The Treatment Specific Mean, Yue Wang, Oliver Bembom, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

An important problem in epidemiology and medical research is the estimation of the causal effect of a treatment action at a single point in time on the mean of an outcome, possibly within strata of the target population defined by a subset of the baseline covariates. Current approaches to this problem are based on marginal structural models, i.e., parametric models for the marginal distribution of counterfactural outcomes as a function of treatment and effect modifiers. The various estimators developed in this context furthermore each depend on a high-dimensional nuisance parameter whose estimation currently also relies on parametric models. Since misspecification …


Finding Cancer Subtypes In Microarray Data Using Random Projections, Debashis Ghosh Oct 2004

Finding Cancer Subtypes In Microarray Data Using Random Projections, Debashis Ghosh

The University of Michigan Department of Biostatistics Working Paper Series

One of the benefits of profiling of cancer samples using microarrays is the generation of molecular fingerprints that will define subtypes of disease. Such subgroups have typically been found in microarray data using hierarchical clustering. A major problem in interpretation of the output is determining the number of clusters. We approach the problem of determining disease subtypes using mixture models. A novel estimation procedure of the parameters in the mixture model is developed based on a combination of random projections and the expectation-maximization algorithm. Because the approach is probabilistic, our approach provides a measure for the number of true clusters …


Semiparametric Methods For The Binormal Model With Multiple Biomarkers, Debashis Ghosh Oct 2004

Semiparametric Methods For The Binormal Model With Multiple Biomarkers, Debashis Ghosh

The University of Michigan Department of Biostatistics Working Paper Series

Abstract: In diagnostic medicine, there is great interest in developing strategies for combining biomarkers in order to optimize classification accuracy. A popular model that has been used when one biomarker is available is the binormal model. Extension of the model to accommodate multiple biomarkers has not been considered in this literature. Here, we consider a multivariate binormal framework for combining biomarkers using copula functions that leads to a natural multivariate extension of the binormal model. Estimation in this model will be done using rank-based procedures. We also discuss adjustment for covariates in this class of models and provide a simple …


Decorrelation: Sufficient For Convolutive Blind Source Separation?, Jiangtao Xi, T. Mei, Joe F. Chicharo, F. Yin Oct 2004

Decorrelation: Sufficient For Convolutive Blind Source Separation?, Jiangtao Xi, T. Mei, Joe F. Chicharo, F. Yin

Faculty of Informatics - Papers (Archive)

This paper considers blind separation of signal sources in a convolutive mixing environment. It tries to show that decorrelation is sufficient for separation of convolutively mixed sources. Two algorithms are also proposed and tested by computer simulations.


Blur Retrieval Via Separation Of Zeros Sheets From Noisy Blurred Images, Prashan Premaratne, I. Burnett, C. D. Liyanage Oct 2004

Blur Retrieval Via Separation Of Zeros Sheets From Noisy Blurred Images, Prashan Premaratne, I. Burnett, C. D. Liyanage

Faculty of Informatics - Papers (Archive)

A novel method of separating the point spread function from blurred images using zeros of the Z transform is presented when more than one blurred image is available. The proposed method is demonstrated to be effective with significant contamination with signal-to-noise ratios of over 30 dB. This method holds much promise as a blind deconvolution (i.e. problem of recovering two functions from their convolution) technique, as it does not impose any constraints on the point spread function, such as positivity. The article is presented with experimental results over different signal-to-noise ratios, depicting its effectiveness as a practical image restoration technique.


Long-Term Mechanical Behavior Of Yucca Mountain Tuffs, And Its Variability, Jaak J.K. Daemen, George Danko, Jaime Gonzalez, Amy J. Smiecinski, Raymond E. Keeler Oct 2004

Long-Term Mechanical Behavior Of Yucca Mountain Tuffs, And Its Variability, Jaak J.K. Daemen, George Danko, Jaime Gonzalez, Amy J. Smiecinski, Raymond E. Keeler

Publications (YM)

We propose to continue the investigation of the long term strength of Yucca Mountain tuffs, with particular emphasis on tuffs from and near the emplacement horizon. We propose to also continue and expand the investigation of the spatial variability of rock strength and stiffness. An intrinsic component of this planned rock testing is the testing of rock joints. Although the emphasis is on tests aimed at determining long term strength, as part of the testing measurements of stiffness also are collected, and will be collected, reported, and analyzed.


Unfolding Smooth Prismatoids, Nadia Benbernou, Patricia Cahn, Joseph O'Rourke Oct 2004

Unfolding Smooth Prismatoids, Nadia Benbernou, Patricia Cahn, Joseph O'Rourke

Computer Science: Faculty Publications

We define a notion for unfolding smooth, ruled surfaces, and prove that every smooth prismatoid (the convex hull of two smooth curves lying in parallel planes), has a nonoverlapping “volcano unfolding.” These unfoldings keep the base intact, unfold the sides outward, splayed around the base, and attach the top to the tip of some side rib. Our result answers a question for smooth prismatoids whose analog for polyhedral prismatoids remains unsolved.


Survey And Census Techniques For Canids, E. M. Gese Oct 2004

Survey And Census Techniques For Canids, E. M. Gese

United States Department of Agriculture Wildlife Services: Staff Publications

We already know that the status and distribution of canid populations throughout the world is of growing concern for biologists and the public alike. Habitat loss, fragmentation and degradation, human persecution, decreases in prey, disease, poaching, and increased competition with other carnivores due to reduced space and habitat, have led to some canid species facing extinction, while others occupy only a fraction of their former range. While reintroductions of some species have been successful (e.g., grey wolves Canis lupus to the Northern Rockies of the U.S.), other species face an uncertain future (e.g., African wild dogs Lycaon pictus). Paramount …


Central And North America (Nearctic), E. M. Gese, M. Bekoff Oct 2004

Central And North America (Nearctic), E. M. Gese, M. Bekoff

United States Department of Agriculture Wildlife Services: Staff Publications

Coyotes appear slender with “a long, narrow, pointed nose; small rounded nose pads; large pointed ears; slender legs; small feet; and a bushy tail...” (Young and Jackson 1951). Size varies geographically (Young and Jackson 1951) (Table 4.1.1), although adult males are heavier and larger than adult females. They range in color from pure grey to rufous; melanistic coyotes are rare (Young and Jackson 1951). Fur texture and color varies geographically: northern subspecies have long coarse hair, coyotes in the desert tend to be fulvous in color, while coyotes at higher latitudes are darker and more grey (Young and Jackson 1951). …


Location Of The Optical Reverse Shock In The Cassiopeia A Supernova Remnant, Jon A. Morse, Robert A. Fesen, Roger A. Chevalier, Kazimierz J. Borkowski Oct 2004

Location Of The Optical Reverse Shock In The Cassiopeia A Supernova Remnant, Jon A. Morse, Robert A. Fesen, Roger A. Chevalier, Kazimierz J. Borkowski

Dartmouth Scholarship

We use two epochs of Hubble Space Telescope WFPC2 images separated by 2 yr to determine the location and propagation of the reverse shock (RS) in the young supernova remnant Cassiopeia A (Cas A). The images trace optical line emission from fast-moving knots and filaments of highly processed ejecta as they cross the RS, become heated and compressed, and radiatively cool. At numerous positions around the optical shell, new emission features are seen in the 2002 images that were not yet visible in the 2000 exposures. In a few instances emission features seen in the first epoch have completely disappeared …


Controlling Dissociative Adsorption For Effective Growth Of Carbon Nanotubes, Vijaya Kayastha, Yoke Khin Yap, Svetlana Dimovski, Yury Gogotsi Oct 2004

Controlling Dissociative Adsorption For Effective Growth Of Carbon Nanotubes, Vijaya Kayastha, Yoke Khin Yap, Svetlana Dimovski, Yury Gogotsi

Department of Physics Publications

Dissociative adsorption has been widely simplified as part of the vapor–liquid–solid (VLS) growth model. We found that the addition of specific carrier gases can critically modify the growth rate and growth density of multiwall carbon nanotubes (MWNTs). These results were explained by dissociative adsorption of C2H2 molecules and a solid-core VLS growth model. Based on these integrated mechanisms, vertically aligned MWNTs were grown with an initial growth rate as high as ∼800μm∕h. This efficient growth process results at temperature and C2H2 partial pressures at which the decomposition and segregation rates of carbon are balanced. …


Automated Motion Synthesis For Virtual Choreography, Gazihan Alankus, A. Alphan Bayazit, O. Burchan Bayazit Oct 2004

Automated Motion Synthesis For Virtual Choreography, Gazihan Alankus, A. Alphan Bayazit, O. Burchan Bayazit

All Computer Science and Engineering Research

In this paper, we present a technique to automati-cally synthesize dancing moves for arbitrary songs. Our current implementation is for virtual characters, but it is easy to use the same algorithms for entertainer robots, such as robotic dancers, which fits very well to this year’s conference theme. Our technique is based on analyzing a musical tune (can be a song or melody) and synthesizing a motion for the virtual character where the character’s movement synchronizes to the musical beats. In order to analyze beats of the tune, we developed a fast and novel algorithm. Our motion synthesis algorithm analyze library …


Red Rock Desert Learning Center Core Group Meeting: October 19, 2004, Red Rock Desert Learning Center Oct 2004

Red Rock Desert Learning Center Core Group Meeting: October 19, 2004, Red Rock Desert Learning Center

Reports (RRLC)

  1. Introductions (5 min.)
  2. Approval of Minutes from September 21 Meeting (5 minutes)
  3. Review & Discussion of Suggested Core Curriculum Themes – Jeanne Klockow/Michael Reiland (20 min.)
  4. Update from Line and Space Architects – Les Wallach/Henry Tom (20 min.)
  5. Standing Reports (20 minutes)
    A. UNLV/CESU Update – Nancy Flagg
    C. BLM Update – Michael Reiland
  6. Committee Reports (10 min.)
    A. Building – Angie Lara
    B. Design Oversight – David Frommer
    C. Educational Programs – Paul Buck
    D. Fund-Raising & Partnerships – Blaine Benedict
    E. NEPA – Charles Carroll
    F. Operations – Jack Ramsey
    G. Other Uses – Pat Williams
    H. Wild …


2nd National Invasive Rodent Summit Oct 2004

2nd National Invasive Rodent Summit

United States Department of Agriculture Wildlife Services: Staff Publications

Papers (abstracts follow)

Historical perspectives and current ecological impacts of nutria in Louisiana
Urban desert islands
Flea control on wild rodents
An overview of rodent control to protect biodiversity on mainland New Zealand
Risk assessment of rodenticide use in New Zealand
Rodents on oceanic islands
Invasive species
Improving the management of rat control damage on the Caribbean National Forest
The USGS role in nutria research and management
Controlling roof rats (Rattus rattus) for protection of Puerto Rican parrots
Anticoagulant resistance in farm rat populations in the UK
Invasive rodent research priorities in New Zealand
The National Invasive Species Council
Integrated …


Cholesky Residuals For Assessing Normal Errors In A Linear Model With Correlated Outcomes: Technical Report, E. Andres Houseman, Louise Ryan, Brent Coull Oct 2004

Cholesky Residuals For Assessing Normal Errors In A Linear Model With Correlated Outcomes: Technical Report, E. Andres Houseman, Louise Ryan, Brent Coull

Harvard University Biostatistics Working Paper Series

Despite the widespread popularity of linear models for correlated outcomes (e.g. linear mixed models and time series models), distribution diagnostic methodology remains relatively underdeveloped in this context. In this paper we present an easy-to-implement approach that lends itself to graphical displays of model fit. Our approach involves multiplying the estimated margional residual vector by the Cholesky decomposition of the inverse of the estimated margional variance matrix. The resulting "rotated" residuals are used to construct an empirical cumulative distribution function and pointwise standard errors. The theoretical framework, including conditions and asymptotic properties, involves technical details that are motivated by Lange and …


Ferroelectric Nanomesa Formation From Polymer Langmuir-Blodgett Films, Mengjun Bai, Stephen Ducharme Oct 2004

Ferroelectric Nanomesa Formation From Polymer Langmuir-Blodgett Films, Mengjun Bai, Stephen Ducharme

Stephen Ducharme Publications

We report the fabrication and characterization of nanoscale ferroelectric structures consisting of disk-shaped nanomesas averaging 8.7±0.4 nm in height and 95±22 nm in diameter, and nanowells 9.8±3.3 nm in depth and 128±37 nm in diameter, formed from Langmuir–Blodgett films of vinylidene fluoride copolymers after annealing in the paraelectric phase. The nanomesas retain the ferroelectric properties of the bulk material and so may be suitable for use in high-density nonvolatile random-access memories, acoustic transducer arrays, or infrared imaging arrays. The nanomesa and nanowell patterns may provide useful templates for nanoscale molding or contact-printing.


Implementation And Comparison Of Denial Of Service Attack Techniques, Khaled M. Elleithy, Drazen Blagovic, Wang K. Cheng, Paul Sideleau Oct 2004

Implementation And Comparison Of Denial Of Service Attack Techniques, Khaled M. Elleithy, Drazen Blagovic, Wang K. Cheng, Paul Sideleau

School of Computer Science & Engineering Faculty Publications

A denial of service attack (DOS) is any type of attack on a networking structure to disable a server from servicing its clients. Attacks range from sending millions of requests to a server in an attempt to slow it down, flooding a server with large packets of invalid data, to sending requests with an invalid of spoofed IP address. In this paper we show the implementation and analysis of three main types of attack: Ping of Death, TCP SYN Flood, and Distributed DOS. The Ping of Death attack will be simulated against a Microsoft Windows 95 computer. The TCP SYN …


Indirect Effects Of Carnivores On Livestock Foraging Behavior And Production, Larry D. Howery, Thomas J. Deliberto Oct 2004

Indirect Effects Of Carnivores On Livestock Foraging Behavior And Production, Larry D. Howery, Thomas J. Deliberto

Sheep and Goat Research Journal

Direct effects of predation (i.e., killing of animals) can result in significant economic losses to livestock producers. A recent publication by the USDA, Wildlife Services (2002) identified the following losses: (1) livestock losses attributed to predators, predominantly coyotes (Canis latrans), reach about $71 million annually; (2) cattle and calf losses to predators in the United States totaled 147,000 head during 2000. A National Agricultural Statistics Service (NASS) study valued these losses at $51.6 million; (3) sheep and lamb losses to predators in the United States totaled 273,000 in 1999. A NASS study valued these losses at $16.5 million; (4) In …


Coyote In The Edwards Plateau Of Texas — An Update, Gary Nunley Oct 2004

Coyote In The Edwards Plateau Of Texas — An Update, Gary Nunley

Sheep and Goat Research Journal

In the early 1900s, organized predator control was initiated to remove coyotes and wolves from the sheep- and goat-producing areas of Texas. Operations were begun in the Edwards Plateau, the largest area of sheep concentration. The Edwards Plateau and, to a lesser extent, portions of other adjoining ecological areas presently account for 18% (1.2 million head) of the sheep and lambs and 85% (1.2 million head) of the goats in the United States (Texas Agriculture Statistics Service, 2004). These numbers are down in both actual numbers and as a percent of the national flocks. It is important that the industries …


Non-Lethal Alternatives For Predation Management, John A. Shivik Oct 2004

Non-Lethal Alternatives For Predation Management, John A. Shivik

Sheep and Goat Research Journal

The ethical milieu in which wildlife biologists and livestock producers work continues to change as the concepts of environmentalism and animal rights and welfare have become introduced and normalized (Singer, 1975). The American public, including livestock producers, are mired within a typically human psychological quagmire of having a high demand for benefit, but a low tolerance for cost — that is, economic forces. Americans tend to demand a cheap, reliable food supply, while simultaneously demanding the existence of animals that, through predation activities, drive up production costs. Ironically, members of the urban public who may find fault with food and …


Predation And Livestock Production: Perspective And Overview, Maurice Shelton Oct 2004

Predation And Livestock Production: Perspective And Overview, Maurice Shelton

Sheep and Goat Research Journal

1. Predation is a more serious problem for the livestock industry than most people realize unless they are somehow involved. This problem is almost certain to increase due to the dispersal of feral or wild hogs throughout the country and the expanding range of the reintroduced grey wolf.

2. Because predator species do not respect property or political boundaries, it is important that control efforts be conducted on a national, state or regional basis. At present, these efforts are carried out by the USDA-APHIS Wildlife Service Programs in cooperation with state agencies and livestock producers. Possibly some type of zoning …