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2002

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Articles 511 - 540 of 3435

Full-Text Articles in Physical Sciences and Mathematics

Land-Use And Vegetation In Western Australia : Project Daw27 : National Land And Water Resources Audit, G R. Beeston, A Jm Hopkins, D P. Shepherd Oct 2002

Land-Use And Vegetation In Western Australia : Project Daw27 : National Land And Water Resources Audit, G R. Beeston, A Jm Hopkins, D P. Shepherd

Resource management technical reports

This report details a project to compile detailed land-use data for Western Australia, on pre-European and present vegetation types, and aspects of disturbance of or threats to the present vegetation. Metadata on botanical surveys throughout the state were also compiled.


The Aminopeptidase From Aeromonas Proteolytica: Structure And Mechanism Of Co-Catalytic Metal Centers Involved In Peptide Hydrolysis, Richard C. Holz Oct 2002

The Aminopeptidase From Aeromonas Proteolytica: Structure And Mechanism Of Co-Catalytic Metal Centers Involved In Peptide Hydrolysis, Richard C. Holz

Chemistry Faculty Research and Publications

Enzymes containing multi-metal active sites are central to numerous biological processes and, consequently, characterization of their structure and function is a problem of outstanding importance. One of the least-explored groups of enzymes is the hydrolases that contain dinuclear metal centers. These enzymes play key roles in carcinogenesis, tissue repair, and protein degradation processes. In addition, some of these enzymes can catalyze the hydrolysis of phosphorus(V) compounds found in nerve gases and agricultural neurotoxins. The determination of detailed reaction mechanisms for these enzymes is required for the design of highly potent, specific inhibitors that can function as potential pharmaceuticals. Hydrolytic enzymes …


Cache Invalidation And Replacement Strategies For Location-Dependent Data In Mobile Environments, Baihua Zheng, Jianliang Xu, Dik Lun Lee Oct 2002

Cache Invalidation And Replacement Strategies For Location-Dependent Data In Mobile Environments, Baihua Zheng, Jianliang Xu, Dik Lun Lee

Research Collection School Of Computing and Information Systems

Mobile location-dependent information services (LDISs) have become increasingly popular in recent years. However, data caching strategies for LDISs have thus far received little attention. In this paper, we study the issues of cache invalidation and cache replacement for location-dependent data under a geometric location model. We introduce a new performance criterion, called caching efficiency, and propose a generic method for location-dependent cache invalidation strategies. In addition, two cache replacement policies, PA and PAID, are proposed. Unlike the conventional replacement policies, PA and PAID take into consideration the valid scope area of a data value. We conduct a series of simulation …


Adiabatic Invariance With First Integrals Of Motion, Artur D. Adib Oct 2002

Adiabatic Invariance With First Integrals Of Motion, Artur D. Adib

Dartmouth Scholarship

The construction of a microthermodynamic formalism for isolated systems based on the concept of adiabatic invariance is an old but seldom appreciated effort in the literature, dating back at least to P. Hertz [Ann. Phys. (Leipzig) 33, 225 (1910)]. An apparently independent extension of such formalism for systems bearing additional first integrals of motion was recently proposed by Hans H. Rugh [Phys. Rev. E 64, 055101 (2001)], establishing the concept of adiabatic invariance even in such singular cases. After some remarks in connection with the formalism pioneered by Hertz, it will be suggested that such an extension can …


Sea Level Slopes And Volume Fluxes Produced By Atmosphere Forcing In Chesapeake Bay, David Salas Monreal Oct 2002

Sea Level Slopes And Volume Fluxes Produced By Atmosphere Forcing In Chesapeake Bay, David Salas Monreal

OES Theses and Dissertations

Year long time series at eight stations in the Chesapeake Bay and inner shelf were used to determine the relative influence of wind, barometric pressure and thermosteric effects on subtidal sea level variability and slopes. Special emphasis was placed on the lower Chesapeake Bay, where inverse barometric effects accounted for up to 33% of the subtidal sea level variations and thermosteric effects accounted for less than 1 % of the variations. The greatest thermosteric influence was noted at the southernmost, saltier and shallower location (Chesapeake Bay Bridge Tunnel). Wind forcing accounted for most of this station's variability, making up more …


The Crest, Fall 2002, Virginia Institute Of Marine Science Oct 2002

The Crest, Fall 2002, Virginia Institute Of Marine Science

Reports

Table of Contents:

  • VIMS researchers win 5-year, $1.7 million NSF award
  • Pair complete 3-year study of clam disease
  • VIMS joins National Shark Research Consortium
  • McNinch receives Young Investigator award
  • Field research sheds light on barndoor skate
  • Management is key to scallop fishery's success
  • VIMS acquires new code for model
  • Yes vote on bond referendum good news for VIMS
  • CBNERR announces Summer 2003 educational programs
  • Workshop series targets charter boat operators
  • Ducklow elected AAAS Fellow
  • VIMS takes to the air(port)
  • VIMS scientists to host international conferences
  • Web update
  • VIMS researchers in educational videos
  • Hoenig writes "hot paper"
  • VIMS and partners win …


Sustainability Issues For Agriculture In Western Australia, Anne Bennett, Ross Kingwell, Ross George Oct 2002

Sustainability Issues For Agriculture In Western Australia, Anne Bennett, Ross Kingwell, Ross George

All other publications

Agriculture has been and will continue to be a major component of economic activity in several regions in Western Australia, and agricultural communities will remain an important part of the social fabric and landscape of the State. Promoting the sustainability of agriculture is likely to produce three main outcomes: vibrant rural communities; profitable agricultural systems; and conservation of the natural environment. This paper describes briefly the main challenges to the sustainability of agriculture and outlines some means of responding to the challenges: market-based approaches; agricultural and environmental research and development; accelerated adjustment; and global and national policy initiatives.


Recurrent Neural Networks And Algorithms For Reconstruction Of Images From Noisy And/Or Partial Data, Ming-Jung Seow Oct 2002

Recurrent Neural Networks And Algorithms For Reconstruction Of Images From Noisy And/Or Partial Data, Ming-Jung Seow

Electrical & Computer Engineering Theses & Dissertations

In this thesis, modular architectures and neighborhood-distance based learning algorithms for fast and effective convergence with increased storage capacity of Hopfield neural networks are presented. The main objective of this research work is to better understand the function of recurrent neural networks and the influence of modularity within a network, and to design, implement, and test the performance of modular Hopfield neural networks for pattern association. Mathematical analysis and results are provided to show that the speed, storage capacity, and generalization capability of the recurrent networks are improved significantly by incorporating the modular architectures and learning algorithms. A new ratio …


An Isolated, Recently Shocked Ism Cloud In The Cygnus Loop Supernova Remnant, D. J. Patnaude, R. A. Fesen, J. C. Raymond, N. A. Levenson Oct 2002

An Isolated, Recently Shocked Ism Cloud In The Cygnus Loop Supernova Remnant, D. J. Patnaude, R. A. Fesen, J. C. Raymond, N. A. Levenson

Dartmouth Scholarship

Spatially resolved ROSAT X-ray and ground-based optical data for the southwestern region of the Cygnus Loop supernova remnant (SNR) reveal in unprecedented detail the very early stages of a blast-wave interaction with an isolated interstellar cloud. Numerous internal cloud shock fronts near the upstream flow and along the cloud edges are visible optically as sharp filaments of enhanced H emission. Faint X-ray emission is seen along a line of Balmer-dominated shock filaments north and south of the cloud with an estimated X-ray gas temperature of 1.2 106 K (0.11 keV), corresponding to a shock velocity of 290 km s1 . …


Support For Statistical Analysis Of The Configurable Port Simulation (Cports), Saurav Mazumdar Oct 2002

Support For Statistical Analysis Of The Configurable Port Simulation (Cports), Saurav Mazumdar

Electrical & Computer Engineering Theses & Dissertations

The primary objective of this thesis is to provide support for statistical analysis of CPortS: a transportation logistics simulation, which models the movement of military traffic through seaports and the interaction of the traffic with port infrastructure. By any standards, CPortS is a very large, data intensive simulation. It provides capabilities for analyzing many important issues such as port clearance and throughput. CPortS was classically run in single run mode. Only a single replication of the simulation was performed and conclusions were drawn from the results obtained. Users and analysts of CPortS performed multiple runs only to see the effect …


Yet Another Algorithm For Pitch Tracking (Yaapt), Kavita Kasi Oct 2002

Yet Another Algorithm For Pitch Tracking (Yaapt), Kavita Kasi

Electrical & Computer Engineering Theses & Dissertations

This thesis presents a pitch detection algorithm that is extremely robust for both high quality and telephone speech. The kernel method for this algorithm is the Normalized Cross Correlation (NCCF) reported by David Talkin [16]. Major innovations include: processing of the original acoustic signal and a nonlinearly processed version of the signal to partially restore very weak F0 components; intelligent peak picking to select multiple F0 candidates and assign merit factors; and, incorporation of highly robust pitch contours obtained from smoothed versions of low frequency portions of spectrograms. Dynamic programming is used to find the ''best" pitch track among all …


Approaching High Fidelity Human Tracking And Representation In Interactive Virtual Environments, Taimur K. Khan Oct 2002

Approaching High Fidelity Human Tracking And Representation In Interactive Virtual Environments, Taimur K. Khan

Electrical & Computer Engineering Theses & Dissertations

This thesis revolves around an Office of Naval Research (ONR) grant known as Virtual Environments for Training (VET). The primary goal is to determine the effectiveness of an immersive environment for training; the secondary goal is to compare the results of this study to a similar study conducted in an environment that is less immersive.

Effectiveness will be determined by the performance of trainees manning a virtual military checkpoint. A four-wall immersive environment employing cave technology will be compared to a three dimensional desktop version of the scenarios employed in the more immersive environment. In order to make this comparison, …


Object-Oriented Architecture For Concurrent Processes In A Port Simulation, Reejo Mathew Oct 2002

Object-Oriented Architecture For Concurrent Processes In A Port Simulation, Reejo Mathew

Electrical & Computer Engineering Theses & Dissertations

An architectural model to represent the resources and infrastructure within a cargo terminal, as well as to support the concurrent but opposite flow of cargo within the terminal, is presented in this thesis. The model supports the configuration of an individual cargo terminal according to its characteristics, as well as the processing involved in the simultaneous flow of cargo in opposite directions through the terminal. This is useful in the analysis of the flow of military cargo and aids the decision-making process to increase the efficiency and throughput of any military operation. This model has been developed with the aim …


A Multilevel Neural Network Architecture For Digital Implementation Of A Face Recognition System Based On Eigenface Approach, Linda Rajan Oct 2002

A Multilevel Neural Network Architecture For Digital Implementation Of A Face Recognition System Based On Eigenface Approach, Linda Rajan

Electrical & Computer Engineering Theses & Dissertations

The design and development of the digital implementation of a multilevel feed forward neural network architecture for face recognition based on statistical features representing Eigenfaces is presented in this thesis. The architecture is divided into three parts: feature extractor, classifier and identifier, The Eigenface extractor architecture is developed based on an efficient design strategy in which all the M weight values corresponding to the Eigenfaces are generated simultaneously from M images representing the Eigen vectors and the test input image. The multilayer neural network classifier is trained using error backpropagation algorithm. A novel multilevel digital architecture is developed for the …


Understory Species Patterns And Diversity In Old-Growth And Managed Northern Hardwood Forests, Robert M. Scheller, David J. Mladenoff Oct 2002

Understory Species Patterns And Diversity In Old-Growth And Managed Northern Hardwood Forests, Robert M. Scheller, David J. Mladenoff

Environmental Science and Management Faculty Publications and Presentations

Forest management can significantly affect both the diversity and spatial patterning of understory vegetation. However, few studies have considered both diversity and spatial patterning at a stand scale. Our objective was to evaluate the effects of forest management on understory plant communities in northern hardwood forests and assess the processes governing differences in species composition, diversity, and spatial patterns. We sampled understory vegetation (all speciestall) and percentage of light transmission levels in three forest types in 12 mesic northern hardwood stands in northern Wisconsin and the Upper Peninsula of Michigan, USA: old-growth, undisturbed forests; even-aged forests resulting from clearcut logging …


Study Of Transport Properties Of Inas Using Monte Carlo Simulation, Satyanadh Gundimada Oct 2002

Study Of Transport Properties Of Inas Using Monte Carlo Simulation, Satyanadh Gundimada

Electrical & Computer Engineering Theses & Dissertations

The present research is aimed at ascertaining the usefulness of InAs semiconductor material for single photon avalanche photo detectors operating in the Geiger mode at 2 μm wavelengths. InAs is considered as the material suitable for the purpose because of its less bandgap and lower effective mass of the electrons when compared to other semiconductor materials presently in use. Hence, theoretically transient transport properties of bulk InAs are superior and the velocity overshoot phenomena stronger. InAs is a relatively less explored material when compared to other materials like GaAs. The choice of the material is justified with thorough exploration of …


A Mathematical Model Of Bacterial Aerotaxis, Borbala Mazzag, Alex Mogilner Sep 2002

A Mathematical Model Of Bacterial Aerotaxis, Borbala Mazzag, Alex Mogilner

Borbala Mazzag

No abstract provided.


On Porosity Prediction From Seismic Data In Ghawar Field, Saudi Arabia, Thomas M. Loretto Sep 2002

On Porosity Prediction From Seismic Data In Ghawar Field, Saudi Arabia, Thomas M. Loretto

Thomas M Loretto

No abstract provided.


Expressing Logistic Regression Coefficients As Changes In Initial Probability Values: Useful Information For Practitioners, John Fraas, J Michael Drushal, Jef Graham Sep 2002

Expressing Logistic Regression Coefficients As Changes In Initial Probability Values: Useful Information For Practitioners, John Fraas, J Michael Drushal, Jef Graham

John W. Fraas

No abstract provided.


The Analysis Of Placement Values For Evaluating Discriminatory Measures, Margaret S. Pepe, Tianxi Cai Sep 2002

The Analysis Of Placement Values For Evaluating Discriminatory Measures, Margaret S. Pepe, Tianxi Cai

UW Biostatistics Working Paper Series

The idea of using measurements such as biomarkers, clinical data, or molecular biology assays for classification and prediction is popular in modern medicine. The scientific evaluation of such measures includes assessing the accuracy with which they predict the outcome of interest. Receiver operating characteristic curves are commonly used for evaluating the accuracy of diagnostic tests. They can be applied more broadly, indeed to any problem involving classification to two states or populations (D = 0 or D = 1). We show that the ROC curve can be interpreted as a cumulative distribution function for the discriminatory measure Y in the …


On-Site Sewage Disposal Systems & Septage Management For Individual Homes And Small Communities, James R. Hegarty Sep 2002

On-Site Sewage Disposal Systems & Septage Management For Individual Homes And Small Communities, James R. Hegarty

Watershed Management Plans and Reports

The purpose of this paper is two-fold:

To identify alternatives and/or improvements to conventional septic systems for residential sewage collection and treatment for small communities and residential developments.

To research existing ordinances that require on-going management of residential and community septic systems, disposal of septage, and develop a model septic system and septage management ordinance that can apply to Kent County communities.

It is hoped that this study’s recommendations will be adopted in Kent County. Eventually, Kent County’s model program can be used to effect statewide implementation of responsible environmental policies that will improve our environment and public health. The …


Training Of The Exchange-Bias Effect In Nio-Fe Heterostructures, A. Hochstrat, Christian Binek, Wolfgang Kleemann Sep 2002

Training Of The Exchange-Bias Effect In Nio-Fe Heterostructures, A. Hochstrat, Christian Binek, Wolfgang Kleemann

Christian Binek Publications

The training effect of a NiO(001)/Fe(110) heterostructure is studied from magnetic hysteresis loops measured by superconducting quantum interference device magnetometry. Consecutive hysteresis loops exhibit a decreasing exchange bias effect. This behavior is known as the training effect, which reflects the dependence of the exchange bias field on the antiferromagnetic interface magnetization. In order to evidence this dependence, we study the decrease of the total saturation magnetization of the heterostructure for an increasing number of hysteresis cycles. Assuming proportionality between the interface magnetization and the total saturation magnetization, the description of the data is consistent within the phenomenological Meiklejohn Bean approach.


Calibrating A 4-Wheel Mobile Robot, Phillip J. Mckerrow, D. Ratner Sep 2002

Calibrating A 4-Wheel Mobile Robot, Phillip J. Mckerrow, D. Ratner

Faculty of Informatics - Papers (Archive)

When a mobile robot is constructed the odometry must be calibrated. Calibrating a 4-wheel robot requires the accurate measurement of steering angle as well as translation and rotation. Some measurements are made with a tape measure and some with ultrasonic sensors. The measurements are used to determine the parameters of the odometry calibration matrix and the steering kinematic model. A procedure for calibrating a 4-wheel robot is discussed.


Coupling Of Coamps And Wavetech With Improved Wave Physics, Shahrdad Sajjadi, Pat Fitzpatrick, Gueorgui Mostovoi, Yongzuo Li, Matt Bettencourt Sep 2002

Coupling Of Coamps And Wavetech With Improved Wave Physics, Shahrdad Sajjadi, Pat Fitzpatrick, Gueorgui Mostovoi, Yongzuo Li, Matt Bettencourt

Publications

The Model Coupling Executable Library (MCEL), developed at the University of Southern Mississippi's Center of Higher Learning, has been successfully used to couple the Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS) and the ocean wave model WAVEWATCH. An example of its application is shown for Hurricane Gordon, showing that two-way coupling results affects boundary layer physics differently than one-way coupling --- in this case, resulting in larger o z and, consequently, larger surface fluxes and a more intense hurricane. However, since analyzing MCEL is difficult because the wave physics is inaccurate, improvements to the wave algorithms are also part of the …


Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823 For Transmutation Applications: Annual Progress Report (September 2001 – August 2002), Ajit K. Roy, Brendan O'Toole Sep 2002

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823 For Transmutation Applications: Annual Progress Report (September 2001 – August 2002), 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. Very little data exist in the open literature on the tensile properties of this alloy. The test material will be thermally treated prior to the evaluation of its tensile properties at temperatures relevant to the transmutation applications. The deformation characteristics of tensile specimens, upon completion of testing, will be evaluated by surface …


Development Of A Systems Engineering Model Of The Chemical Separations Process, Yitung Chen, Randy Clarksean, Darrell Pepper Sep 2002

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

Separations Campaign (TRP)

The AAA program is developing technology for the transmutation of nuclear waste to address many of the long-term disposal issues. An integral part of this program is the proposed chemical separations scheme. This process, as envisioned by Argonne National Laboratory (ANL) researchers, will be outlined later in this report.

Nearly all issues related to risks to future generations arising from long-term disposal of such spent nuclear fuel is attributable to ~1% of its content. This 1% is made up primarily of plutonium, neptunium, americium, and curium (the transuranic elements) and long-lived isotopes of iodine and technetium created as products from …


Late Quaternary Slip Rates Across The Central Tien Shan, Kyrgyzstan, Central Asia, Stephen C. Thompson, Ray J. Weldon, Charles M. Rubin, Kanatbek Abdrakhmatov, Peter Molnar, Glenn W. Berger Sep 2002

Late Quaternary Slip Rates Across The Central Tien Shan, Kyrgyzstan, Central Asia, Stephen C. Thompson, Ray J. Weldon, Charles M. Rubin, Kanatbek Abdrakhmatov, Peter Molnar, Glenn W. Berger

All Faculty Scholarship for the College of the Sciences

Slip rates across active faults and folds show that late Quaternary faulting is distributed across the central Tien Shan, not concentrated at its margins. Nearly every intermontane basin contains Neogene and Quaternary syntectonic strata deformed by Holocene north‐south shortening on thrust or reverse faults. In a region that spans two thirds of the north‐south width of the central Tien Shan, slip rates on eight faults in five basins range from ∼0.1 to ∼3 mm/yr. Fault slip rates are derived from faulted and folded river terraces and from trenches. Radiocarbon, optically stimulated luminescence, and thermoluminescence ages limit ages of terraces and …


Whole Mantle Shear Structure Beneath The East Pacific Rise, Timothy I. Melbourne, Donald V. Helmberger Sep 2002

Whole Mantle Shear Structure Beneath The East Pacific Rise, Timothy I. Melbourne, Donald V. Helmberger

All Faculty Scholarship for the College of the Sciences

We model broadband seismograms containing triplicated S, S2, and S3 along with ScS to produce a pure path one‐dimensional model extending from the crust to the core‐mantle boundary beneath the East Pacific Rise. We simultaneously model all body wave shapes and amplitudes, thereby eliminating depth‐velocity ambiguities. The data consist of western North American broadband recordings of East Pacific Rise (EPR) affiliate transform events that form a continuous record section out to 82° and sample nearly the entire East Pacific Rise. The best fitting synthetics contain attenuation and small changes in lithospheric thickness needed to correct for …


Accelerated Hazards Model: Method, Theory And Applications, Ying Qing Chen, Nicholas P. Jewell, Jingrong Yang Sep 2002

Accelerated Hazards Model: Method, Theory And Applications, Ying Qing Chen, Nicholas P. Jewell, Jingrong Yang

U.C. Berkeley Division of Biostatistics Working Paper Series

In an accelerated hazards model, the hazard functions of a failure time are related through the time scale-change, which is often a function of covariates and associated parameters. When the hazard functions have special properties, such as monotonicity in time, the parameters may be clinically meaningful in measuring a treatment effect. This paper reviews methodological and theoretical development of this model. Applications of the accelerated hazards model including sample size calculation in clinical trials, are also explored.


Using The Emulab Network Testbed To Evaluate The Armada I/O Framework For Computational Grids, Ron Oldfield, David Kotz Sep 2002

Using The Emulab Network Testbed To Evaluate The Armada I/O Framework For Computational Grids, Ron Oldfield, David Kotz

Computer Science Technical Reports

This short report describes our experiences using the Emulab network testbed at the University of Utah to test performance of the Armada framework for parallel I/O on computational grids.