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2002

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Articles 121 - 150 of 2989

Full-Text Articles in Physical Sciences and Mathematics

Resource Annotation Framework In A Georeferenced And Geospatial Digital Library, Zehua Liu, Ee Peng Lim, Dion Hoe-Lian Goh Dec 2002

Resource Annotation Framework In A Georeferenced And Geospatial Digital Library, Zehua Liu, Ee Peng Lim, Dion Hoe-Lian Goh

Research Collection School Of Computing and Information Systems

G-Portal is a georeferenced and geospatial digital library that aims to identify, classify and organize geospatial and georeferenced resources on the web and to provide digital library services for these resources. Annotation service is supported in G-Portal to enable users to contribute content to the digital library. In this paper, we present a resource annotation framework for georeferenced and geospatial digital libraries and discuss its application in G-Portal. The framework is fiexible for managing annotations of heterogeneous web resources. It allows users to contribute not only the annotation content but also the schema of the annotations. Meanwhile, other digital library …


A Data Mining Approach To Library New Book Recommendations, San-Yih Hwang, Ee Peng Lim Dec 2002

A Data Mining Approach To Library New Book Recommendations, San-Yih Hwang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

In this paper, we propose a data mining approach to recommending new library books that have never been rated or borrowed by users. In our problem context, users are characterized by their demographic attributes, and concept hierarchies can be defined for some of these demographic attributes. Books are assigned to the base categories of a taxonomy. Our goal is therefore to identify the type of users interested in some specific type of books. We call such knowledge generalized profile association rules. In this paper, we propose a new definition of rule interestingness to prune away rules that are redundant and …


An Efficient Burst-Arrival And Batch- Departure Algoriths For Round-Robin Service, Jorge R. Ramos, Janche Sang Dec 2002

An Efficient Burst-Arrival And Batch- Departure Algoriths For Round-Robin Service, Jorge R. Ramos, Janche Sang

Department of Computer Science Technical Reports

No abstract provided.


Computer Sciences At Purdue University 1962 To 2000, John R. Rice, Saul Rosen Dec 2002

Computer Sciences At Purdue University 1962 To 2000, John R. Rice, Saul Rosen

Department of Computer Science Technical Reports

No abstract provided.


Performance Of Multi-Dimensional Space- Filling Curves, Mohamed F. Mokbel, Walid G. Aref, Ibrahim Kamel Dec 2002

Performance Of Multi-Dimensional Space- Filling Curves, Mohamed F. Mokbel, Walid G. Aref, Ibrahim Kamel

Department of Computer Science Technical Reports

No abstract provided.


Periodicity Detection In Time Series Databases, Mohamed G. Elfeky, Walid G. Aref, Mikhail J. Atallah Dec 2002

Periodicity Detection In Time Series Databases, Mohamed G. Elfeky, Walid G. Aref, Mikhail J. Atallah

Department of Computer Science Technical Reports

No abstract provided.


Multi-Dimenstional Traversals For Normalization Constants, Jorge R. Ramos, Vernon J. Rego Dec 2002

Multi-Dimenstional Traversals For Normalization Constants, Jorge R. Ramos, Vernon J. Rego

Department of Computer Science Technical Reports

No abstract provided.


Quiet Time Variability Of The Geosynchronous Magnetic Field And Its Response To The Solar Wind, Jeff Sanny, J. A. Tapia, D. G. Sibeck, M. B. Moldwin Dec 2002

Quiet Time Variability Of The Geosynchronous Magnetic Field And Its Response To The Solar Wind, Jeff Sanny, J. A. Tapia, D. G. Sibeck, M. B. Moldwin

Physics Faculty Works

We present a survey of the variability of the geosynchronous magnetic field strength on the dayside using observations by the GOES satellites over a period exceeding 4 years. Only intervals of reduced geomagnetic activity, as defined by Dst > −20 nT, were considered in this study. The magnetic field strength data were filtered with a passband of 1.7 mHz to 17 mHz (1–10 minutes), a process that eliminates the diurnal variation of the field strength and the effects of most of the higher frequency (>17 mHz) ultralow-frequency (ULF) waves. The geosynchronous field strength appears to exhibit the greatest variability in …


Effects Of Acid Mine Drainage On Limnological Conditions And Fish Assemblages In The Cumberland Plateau Region Of The North Chickamauga Creek System, Tennessee, Jennifer Copeland Backer Dec 2002

Effects Of Acid Mine Drainage On Limnological Conditions And Fish Assemblages In The Cumberland Plateau Region Of The North Chickamauga Creek System, Tennessee, Jennifer Copeland Backer

Masters Theses and Doctoral Dissertations

Acid mine drainage (AMD) is the primary water pollution problem in Appalachian streams. The Cumberland Plateau (Southwestern Appalachians ecoregion) portion of North Chickamauga Creek (NCC), a fourth-order tributary to the Tennessee River (Tennessee), has been impacted by decades of AMD from active and abandoned coal mines. I assessed stream characteristics at 19 sites in the Cumberland Plateau region of the NCC system; these data were used to create a GIS database. Limnological conditions and fish assemblage attributes were compared between AMD-impacted and reference sites. Relationships were examined among water quality, habitat, and fish assemblage variables. Stream pH averaged lower at …


Effect Of Riparian Land Use On The Biotic Integrity Of Fish Assemblages In Black Creek, Chattanooga, Tennessee, Jerri Leigh Phillips Dec 2002

Effect Of Riparian Land Use On The Biotic Integrity Of Fish Assemblages In Black Creek, Chattanooga, Tennessee, Jerri Leigh Phillips

Masters Theses and Doctoral Dissertations

Black Creek is a third-order Ridge and Valley stream (Tennessee River drainage) in Chattanooga, Tennessee. Most ofBlack Creek's watershed is forested (ca. 71% in 1991 ). However, increasing urban development, particularly along the riparian landscapes, could impact the stream's ecological health. I assessed fish assemblages (biotic integrity), water quality, instream habitat, and riparian land-use features at eight sites in Black Creek, May-June 2000. Water quality conditions (temperature, dissolved oxygen, pH, conductivity) were favorable for stream fishes, but some level of habitat degradation (bank erosion, sedimentation, loss of riparian vegetation) was observed at all sites. Electrofishing samples yielded a total of29 …


Crystalclear: Active Visualization Of Association Rules, Hian-Huat Ong, Kok-Leong Ong, Wee-Keong Ng, Ee Peng Lim Dec 2002

Crystalclear: Active Visualization Of Association Rules, Hian-Huat Ong, Kok-Leong Ong, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Effective visualization is an important aspect of active data mining. In the context of association rules, this need has been driven by the large amount of rules produced from a run of the algorithm. To be able to address real user needs, the rules need to be summarized and organized so that it can be interpreted and applied in a timely manner. In this paper, we propose two visualization techniques that is an improvement over those used by existing data mining packages. In particular, we address the visualization of "differences" in the set of rules due to incremental changes in …


Upper Spokane River Model: Boundary Conditions And Model Setup, 2001, Spencer Slominski, Robert Leslie Annear, Chris Berger, Scott A. Wells Dec 2002

Upper Spokane River Model: Boundary Conditions And Model Setup, 2001, Spencer Slominski, Robert Leslie Annear, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:

• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam for 2001 based on the calibration conducted for 1991 and 2000 data sets, (Annear et al, 2001).

• Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen …


Microbial Community Structure In Hydrocarbon Impacted Sediment Associated With Anomalous Geophysical Signatures, Joseph W. Duris Dec 2002

Microbial Community Structure In Hydrocarbon Impacted Sediment Associated With Anomalous Geophysical Signatures, Joseph W. Duris

Masters Theses

The Crystal Refinery is a former refinery site in Carson City Michigan that has had historic releases of refined and unrefined crude oil dating back to the late 1940's. The contamination of soil with light non-aqueous phase liquids (LNAPL) has had a dynamic impact on the subsurface environment in adjacent Carson City Park. Very little is known about the complex interactions between microbial communities, geochemistry and geophysics. In order to investigate possible connections between these parameters a multidisciplinary study was undertaken to investigate the hypothesis that the degradation of LNAPL by resident microbial communities causes a local increase in organic …


Investigation Of The Corrosion Of Steel By Lead-Bismuth Eutectic (Lbe) Using Scanning Electron Microscopy And X-Ray Photoelectron Spectroscopy, Daniel Koury Dec 2002

Investigation Of The Corrosion Of Steel By Lead-Bismuth Eutectic (Lbe) Using Scanning Electron Microscopy And X-Ray Photoelectron Spectroscopy, Daniel Koury

UNLV Theses, Dissertations, Professional Papers, and Capstones

Lead Bismuth Eutectic (LBE) has been proposed for use in programs for accelerator transmutation of waste. LBE is the leading candidate material as a spallation target and an option for the sub-critical blanket coolant. The corrosion of 316 and 316L stainless steels by LBE has been studied using UNLV's facilities for Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). We have compared exposed and unexposed samples and studied the differences. Some amount of surface contamination is present on the samples and has been removed by ionbeam etching. The unexposed samples reveal typical stainless steel characteristics: a chromium oxide passivation …


Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix: Quarterly Report September-December 2002, Spencer M. Steinberg Dec 2002

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix: Quarterly Report September-December 2002, Spencer M. Steinberg

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. This proposal will develop and examine the use of Fullerene Containing Carbon (FCC) compounds as potential sorbents for iodine release from the reprocessing of nuclear fuel. This work will also include the development of bench-scale testing capabilities at UNLV to allow the testing of the FCC material in a simulated process off-gas environment. This experimental capability will also be used to test other potential sorbtion materials and processes, such as natural organic matter (NOM) and other promising alternatives. …


Robust Residuals And Diagnostics In Autoregressive Time Series, Kirk W. Anderson Dec 2002

Robust Residuals And Diagnostics In Autoregressive Time Series, Kirk W. Anderson

Dissertations

One of the goals of model diagnostics is outlier detection. In particular, we would like to use the residuals, appropriately standardized, to “flag” outliers. Hopefully, our (robust) procedure has yielded a fit that resists undue influence by outlying points, while simultaneously drawing attention to these interesting points via residual analysis. In this study we consider several different methods of standardizing the residuals resulting from autoregression. A large sample approximation for the variance of rank-based first order autoregressive time series residuals is developed. This provides studentized residuals, specific to the time series model and estimation procedure. Simulation studies are presented that …


On Rank-Based Considerations For Generalized Linear Models And Generalized Estimating Equation Models, Diana R. Cucos Dec 2002

On Rank-Based Considerations For Generalized Linear Models And Generalized Estimating Equation Models, Diana R. Cucos

Dissertations

This study discusses rank-based robust methods for estimation of parameters and hypotheses testing in the generalized linear models (GLM) and generalized estimating equations (GEE) setting. The robust estimates are obtained by minimizing a Wilcoxon drop in dispersion function for linear or nonlinear regression models. In addition, diagnostic tools for outliers and influential observations are being developed. These models are generalizations of linear and nonlinear models. They allow for both nonlinear mean functions and heteroscedasticity of their random errors. This makes them quite useful in practice. Rank-based inference has been developed for linear models over the last thirty years. This inference …


Geoelectrical Response Of An Aged Lnapl Plume: Implications For Monitoring Natural Attenuation, Douglas D. Werkema Jr. Dec 2002

Geoelectrical Response Of An Aged Lnapl Plume: Implications For Monitoring Natural Attenuation, Douglas D. Werkema Jr.

Dissertations

The geoelectric stratigraphy at a site impacted with light non-aqueous phase liquids (LNAPLs) is investigated for its link to natural biodegradation, its contribution to the conductive model for aged (i.e. mature) LNAPL contaminated sites, and the relationship to the natural hydrologic regime. The highest conductivities (lowest resistivities) were observed in portions o f soils where LNAPL was in residual and free phase. Corroborating evidence from bacteria enumeration from soil close to the vertical resistivity probe (VRP) installations show orders-of-magnitude increase in both heterotrophic and oil degrading microbes at the depths where the conductivity was at a maximum. The coincidence o …


New Statitstical Methods For The Estimation Of The Mean And Standard Deviation From Normally Distributed Censored Samples, Abou El-Makarim Abd El-Alim Aboueissa Dec 2002

New Statitstical Methods For The Estimation Of The Mean And Standard Deviation From Normally Distributed Censored Samples, Abou El-Makarim Abd El-Alim Aboueissa

Dissertations

The main objective of this dissertation is to estimate the mean /x and standard deviation cr of a normal population from left-censored samples. We have developed new methods for calculating estimates for the mean and standard deviation of a normal population from left-censored samples. Some of these methods based on traditional estimating procedures. A new method of obtaining the Cohen maximum likelihood estimates for fx and cr without the aid of an auxiliary table will be introduced. This new method will be used to extend Cohen table of estimating the Cohen A-parameter that is required for calculating the maximum likelihood …


Load Balancing And Congestion Avoidance Routing, Konstantinos N. Kokkinos Dec 2002

Load Balancing And Congestion Avoidance Routing, Konstantinos N. Kokkinos

Dissertations

Today’s high speed backbone networks are expected to support a wide range of communication-intensive applications. One of the most important issues in Quality of Service (QoS) is efficient routing. Many QoS routing solutions have been published lately for different criteria of QoS requirements and resource constraints. In this dissertation we focus on the design of regular network topologies and suggest efficient routing schemes to reduce the probability of hot spot creation in the network. Furthermore, we provide a detection of congestion mechanism that reroutes traffic to maintain balancing with small communication cost. Several theoretical results relatively to network traffic balancing …


Resolvability In Graphs, Varaporn Saenpholphat Dec 2002

Resolvability In Graphs, Varaporn Saenpholphat

Dissertations

The distance d (u, v ) between two vertices u and v in a connected graph G is the length of a shortest u - v path in G . For an ordered set W = { w1 , w2 , [Special characters omitted.] &cdots; , wk } of vertices in G and a vertex v of G , the code of v with respect to W is the k -vector cW (v ) = (d ( v, w1 ),d (v, w 2 ), [Special characters omitted.] &cdots; , d …


On Clustering And Retrieval Of Video Shots Through Temporal Slices Analysis, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang Dec 2002

On Clustering And Retrieval Of Video Shots Through Temporal Slices Analysis, Chong-Wah Ngo, Ting-Chuen Pong, Hong-Jiang Zhang

Research Collection School Of Computing and Information Systems

Based on the analysis of temporal slices, we propose novel approaches for clustering and retrieval of video shots. Temporal slices are a set of two-dimensional (2-D) images extracted along the time dimension of an image volume. They encode rich set of visual patterns for similarity measure. In this paper, we first demonstrate that tensor histogram features extracted from temporal slices are suitable for motion retrieval. Subsequently, we integrate both tensor and color histograms for constructing a two-level hierarchical clustering structure. Each cluster in the top level contains shots with similar color while each cluster in bottom level consists of shots …


Motion Retrieval By Temporal Slices Analysis, Chong-Wah Ngo, Chong-Wah Ngo, Hong-Jiang Zhang Dec 2002

Motion Retrieval By Temporal Slices Analysis, Chong-Wah Ngo, Chong-Wah Ngo, Hong-Jiang Zhang

Research Collection School Of Computing and Information Systems

In this papel; we investigate video shots retrieval based on the analysis of temporal slice images. Temporal slices are a set of2D images extracted along the time dimension of image sequences. They encode rich set of motion clues for shot similarity measure. Because motion is depicted as texture orientation in temporal slices, we utilize various texture features such as tensor histogram, Gabor feature, and the statistical feature of co-occurrence matrix extracted directly from slices for motion description and retrieval. In this way, motion retrieval can be treated in a similar way as texture retrieval problem. Experimental results indicate that the …


Alignment, Mechanical And Thermo-Physical Characterization Of Nanofiber-Reinforced Polyethylene, Veronica M. Diaz-Serrato Dec 2002

Alignment, Mechanical And Thermo-Physical Characterization Of Nanofiber-Reinforced Polyethylene, Veronica M. Diaz-Serrato

Theses and Dissertations - UTB/UTPA

Alignment of vapor grown carbon nano-reinforced polyethylene composites was performed using conventional extrusion processing methods. The alignment of the nanofibers within polyethylene, PE; the matrix, produced a material with anisotropic behavior. Mechanical and thermo-physical properties of the nanocomposite were studied. Enhancements in mechanical properties were investigated for pure PE, misaligned, and aligned specimens for stress versus strain, maximum load, and Young's modulus as high as 185, 273, and 80%, respectively. In fact, toughness was considerably high for the 10 rpm specimen when compared to other samples of different windup speeds. Thermo-physical studies were performed using differential scanning calorimetry (DSC) and …


Data Mining With Newton's Method., James Dale Cloyd Dec 2002

Data Mining With Newton's Method., James Dale Cloyd

Electronic Theses and Dissertations

Capable and well-organized data mining algorithms are essential and fundamental to helpful, useful, and successful knowledge discovery in databases. We discuss several data mining algorithms including genetic algorithms (GAs). In addition, we propose a modified multivariate Newton's method (NM) approach to data mining of technical data. Several strategies are employed to stabilize Newton's method to pathological function behavior. NM is compared to GAs and to the simplex evolutionary operation algorithm (EVOP). We find that GAs, NM, and EVOP all perform efficiently for well-behaved global optimization functions with NM providing an exponential improvement in convergence rate. For local optimization problems, we …


A Performance Study Of Lam And Mpich On An Smp Cluster, Brian Patrick Kearns Dec 2002

A Performance Study Of Lam And Mpich On An Smp Cluster, Brian Patrick Kearns

Dissertations and Theses

Many universities and research laboratories have developed low cost clusters, built from Commodity-Off-The-Shelf (COTS) components and running mostly free software. Research has shown that these types of systems are well-equipped to handle many problems requiring parallel processing. The primary components of clusters are hardware, networking, and system software. An important system software consideration for clusters is the choice of the message passing library.

MPI (Message Passing Interface) has arguably become the most widely used message passing library on clusters and other parallel architectures, due in part to its existence as a standard. As a standard, MPI is open for anyone …


Power Scaling Feasibility Of Chromium-Doped Ii-Vi Laser Sources And The Demonstration Of A Chromium-Doped Zinc Selenide Face-Cooled Disk Laser, Jason B. Mckay Dec 2002

Power Scaling Feasibility Of Chromium-Doped Ii-Vi Laser Sources And The Demonstration Of A Chromium-Doped Zinc Selenide Face-Cooled Disk Laser, Jason B. Mckay

Theses and Dissertations

Tunable lasers in the 2-4 µm wavelength range are needed for Air Force sensor applications. Chromium-doped II-VI materials are a promising class of laser material for tunable operation in this wavelength range, but until recently had not produced enough output power to meet application requirements. This dissertation investigates Cr2+:II-VI material properties and potential laser designs, then experimentally demonstrates and analyzes the performance of a Cr2+:ZnSe disk laser design that can produce sufficient output power. Cr2+:II-VI laser materials are found to be susceptible to overheating and thermal lensing, but are otherwise satisfactory laser materials. The …


Active Processor Scheduling Using Evolution Algorithms, David J. Caswell Dec 2002

Active Processor Scheduling Using Evolution Algorithms, David J. Caswell

Theses and Dissertations

The allocation of processes to processors has long been of interest to engineers. The processor allocation problem considered here assigns multiple applications onto a computing system. With this algorithm researchers could more efficiently examine real-time sensor data like that used by United States Air Force digital signal processing efforts or real-time aerosol hazard detection as examined by the Department of Homeland Security. Different choices for the design of a load balancing algorithm are examined in both the problem and algorithm domains. Evolutionary algorithms are used to find near-optimal solutions. These algorithms incorporate multiobjective coevolutionary and parallel principles to create an …


Optimization Of Edxrf For The Study Of Heavy Metal Pollution Of Lake Victoria, Nk Mahommed, In Makundi Nov 2002

Optimization Of Edxrf For The Study Of Heavy Metal Pollution Of Lake Victoria, Nk Mahommed, In Makundi

Tanzania Journal of Science

This study reports on the optimisation and calibration of the Energy Dispersive X-ray Fluorescence (EDXRF) spectrometer installed in the Department of Physics, University of Dar es Salaam. The spectrometer was subsequently utilized to determine concentrations of heavy metals in water hyacinth (Eichhornia crassipes (Mart) Solms.) found growing along the shore of Lake Victoria. The optimal conditions and detection limits were determined experimentally by variation of the excitation parameters. The study found that the use of a collimator with two apertures of diameter 4 mm each placed 8 mm apart and made of materials that do not interfere with elements to …


Studies On Benthic Denitrification In The Chwaka Bay Mangrove Sediments, Zanzibar, Sm Mahommed, Rw Johnstone Nov 2002

Studies On Benthic Denitrification In The Chwaka Bay Mangrove Sediments, Zanzibar, Sm Mahommed, Rw Johnstone

Tanzania Journal of Science

Denitrification was measured at three sites in a narrow tidal creek in the Chwaka mangrove ecosystem. Denitrification arising from water column nitrate (Dw) was low (< 0.1μM Nm-2h-1) and there was little spatial and seasonal variation in Dw rates in the creek. Coupled nitrification-denitrification (Dn) was found to be low, but within the range measured in other mangrove sediments. Average values ranged from 0.01 to 0.45 μM Nm-2h-1 and showed strong spatial variations. The low denitrifcation rates observed in the creek were possibly as a result of the low availability of NO3 and high C:N values of the organic matter in the sediment. Spatial variations in denitrification rates were due to variations in concentration levels of organic matter and possibly to disproportionate competition for inorganic nitrogen between denitrifiers and benthic autotrophs among sites. There were no seasonal differences in denitrification rates. Results from the present study suggest that sediment denitrification does not play a major role as a sink for N in this ecosystem