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2007

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Articles 421 - 450 of 6758

Full-Text Articles in Physical Sciences and Mathematics

The Tropical Forest And Fire Emissions Experiment: Method Evaluation Of Volatile Organic Compound Emissions Measured By Ptr-Ms, Ftir, And Gc From Tropical Biomass Burning, T. G. Karl, Ted J. Christian, Robert J. Yokelson, Paulo Artaxo, Wei Min Hao, Alex Guenther Nov 2007

The Tropical Forest And Fire Emissions Experiment: Method Evaluation Of Volatile Organic Compound Emissions Measured By Ptr-Ms, Ftir, And Gc From Tropical Biomass Burning, T. G. Karl, Ted J. Christian, Robert J. Yokelson, Paulo Artaxo, Wei Min Hao, Alex Guenther

Chemistry and Biochemistry Faculty Publications

Volatile Organic Compound (VOC) emissions from fires in tropical forest fuels were quantified using Proton-Transfer-Reaction Mass Spectrometry (PTRMS), Fourier Transform Infrared Spectroscopy (FTIR) and gas chromatography (GC) coupled to PTRMS (GC-PTR-MS). We investigated VOC emissions from 19 controlled laboratory fires at the USFS (United States Forest Service) Fire Sciences Laboratory and 16 fires during an intensive airborne field campaign during the peak of the burning season in Brazil in 2004. The VOC emissions were dominated by oxygenated VOCs (OVOC) (OVOC/NMHC similar to 4:1, NMHC: non-methane hydrocarbons) The specificity of the PTR-MS instrument, which measures the mass to charge ratio of …


Transition Analysis For Moderate Feedback Self-Mixing Interferometry, L. Wei, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo Nov 2007

Transition Analysis For Moderate Feedback Self-Mixing Interferometry, L. Wei, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo

Faculty of Informatics - Papers (Archive)

We present a theoretical analysis on the locations of transition points in moderate feedback self-mixing signal which is a fundamental issue to be addressed in preprocessing experimentally acquired data. Locations for the start and end points for upward and downward switchings are calculated based on the Lang-Kobayashi model and discussions are given, which provides guidance in achieving more accurate signal normalization.


Empirical Likelihood Based Confidence Intervals For The Difference Between Two Sensitivities Of Continuous-Scale Diagnostic Tests At A Fixed Level Of Specificity, Suqin Yao Nov 2007

Empirical Likelihood Based Confidence Intervals For The Difference Between Two Sensitivities Of Continuous-Scale Diagnostic Tests At A Fixed Level Of Specificity, Suqin Yao

Mathematics Theses

Diagnostic testing is essential to distinguish non-diseased individuals from diseased individuals. The sensitivity and specificity are two important indices for the diagnostic accuracy of continuous-scale diagnostic tests. If we want to compare the effectiveness of two tests, it is of interest to construct a confidence interval for the difference of the two sensitivities at a fixed level of specificity. In this thesis, we propose two empirical likelihood based confidence intervals (HBELI and HBELII) for the difference of two sensitivities at a predetermined specificity level. Simulation studies show that when correlation between the two test results exists, HBELI and HBELII intervals …


Empirical Likelihood Confidence Intervals For Generalized Lorenz Curve, Nelly E. Belinga-Hill Nov 2007

Empirical Likelihood Confidence Intervals For Generalized Lorenz Curve, Nelly E. Belinga-Hill

Mathematics Theses

Lorenz curves are extensively used in economics to analyze income inequality metrics. In this thesis, we discuss confidence interval estimation methods for generalized Lorenz curve. We first obtain normal approximation (NA) and empirical likelihood (EL) based confidence intervals for generalized Lorenz curves. Then we perform simulation studies to compare coverage probabilities and lengths of the proposed EL-based confidence interval with the NA-based confidence interval for generalized Lorenz curve. Simulation results show that the EL-based confidence intervals have better coverage probabilities and shorter lengths than the NA-based intervals at 100p-th percentiles when p is greater than 0.50. Finally, two real examples …


Selecting The Working Correlation Structure By A New Generalized Aic Index For Longitudinal Data, Wei-Lun Lin Nov 2007

Selecting The Working Correlation Structure By A New Generalized Aic Index For Longitudinal Data, Wei-Lun Lin

Mathematics Theses

The analysis of longitudinal data has been a popular subject for the recent years. The growth of the Generalized Estimating Equation (GEE) Liang & Zeger, 1986) is one of the most influential recent developments in statistical practice for this practice. GEE methods are attractive both from a theoretical and a practical standpoint. In this paper, we are interested in the influence of different "working" correlation structures for modeling the longitudinal data. Furthermore, we propose a new AIC-like method for the model assessment which generalized AIC from the point of view of the data generating. By comparing the difference of the …


Individual Growth Models Of Change In Peabody Picture Vocabulary Scores Of Children Treated For Brain Tumors, Ying Shen Nov 2007

Individual Growth Models Of Change In Peabody Picture Vocabulary Scores Of Children Treated For Brain Tumors, Ying Shen

Mathematics Theses

The individual growth model is a relatively new statistical technique. It is now widely used to examine the trajectories of individuals and groups in repeated measures data. This study examines the association of the receptive vocabulary over time and characteristics of children who were treated for brain tumors. The children undertook different types of treatment from one to any combinations of surgery, radiation and chemotherapy. The individual growth model is used to analyze the longitudinal data and to address the issues behind the data. Results of this study present several factors' influences to the rate of change of PPVT scores. …


Peer-To-Peer Distributed Syd Directory Synchronization In A Proximity-Based Environment, Sunetri Priyanka Dasari Nov 2007

Peer-To-Peer Distributed Syd Directory Synchronization In A Proximity-Based Environment, Sunetri Priyanka Dasari

Computer Science Theses

Distributed directory services are an evolving paradigm in the distributed computing arena. They are a shift from the centralized directory that causes delay and does not scale well to widespread peer-to-peer networks. With networking becoming more pervasive, there is a need to integrate the heterogeneity of device, data and network with the applications that are built on them. SyD or System on Mobile Devices is a middleware that is being used to implement such a distributed directory service. To provide a persistent global view of data, we serialize and synchronize the distributed directories. The SyD APIs provide a high-level environment …


Intrinsic Absorption With The Far Ultraviolet Spectroscopic Explorer, Jay Patrick Dunn Nov 2007

Intrinsic Absorption With The Far Ultraviolet Spectroscopic Explorer, Jay Patrick Dunn

Physics and Astronomy Dissertations

We present a survey of 72 Seyfert galaxies and quasars observed by the Far Ultraviolet Spectroscopic Explorer (FUSE). Our survey is the largest to date searching for intrinsic UV absorption with high spectral resolution, and is the first step toward a more comprehensive study of intrinsic absorption in low-redshift AGN. We have determined that 72 of 253 available active galactic nuclei (AGN) are viable targets for detection of intrinsic absorption lines. We examined these spectra for signs of intrinsic absorption in the O VI doublet (lambda lamdba 1031.9, 1037.6) and Lyman beta (lambda 1025.7). The fraction of Seyfert 1 galaxies …


Exploring The Role Of Calcium Ions In Biological Systems By Computational Prediction And Protein Engineering, Yubin Zhou Nov 2007

Exploring The Role Of Calcium Ions In Biological Systems By Computational Prediction And Protein Engineering, Yubin Zhou

Chemistry Dissertations

Ca2+, a signal for death and life, is closely involved in the regulation of numerous important cellular events. Ca2+ carries out its function through its binding to Ca2+-receptors or Ca2+-binding proteins. The EF-hand protein, with a helix-loop-helix Ca2+-binding motif, constitutes one of the largest protein families. To facilitate our understanding of the role of Ca2+ in biological systems (denoted as calciomics) using genomic information, an improved pattern search method (http://www.chemistry.gsu.edu/faculty/Yang/Calciomics.htm) for the identification of EF-hand and EF-like Ca2+-binding proteins was developed. This fast and robust method allows us to analyze putative EF-hand proteins at the genome-wide level and further visualize …


Electrokinetic Modeling Of Free Solution Electrophoresis, Yao Xin Nov 2007

Electrokinetic Modeling Of Free Solution Electrophoresis, Yao Xin

Chemistry Dissertations

Modeling electrophoresis of peptides, proteins, DNA, blood cells and colloids is based on classical electrokinetic theory. The coupled field equations-Poisson, Navier-Stokes or Brinkman, and ion transport equations are solved numerically to calculate the electrophoretic mobilities. First, free solution electrophoretic mobility expressions are derived for weakly charged rigid bead arrays. Variables include the number of beads (N), their size (radius), charge, distribution (configuration), salt type, and salt concentration. We apply these mobility expressions to rings, rigid rods, and wormlike chain models and then apply the approach to the electrophoretic mobilities and translational diffusion constants of weakly charged peptides. It is shown …


Brief Account On The 4~(Th) Cse Conference(November 3,2007,Yangzhou) Nov 2007

Brief Account On The 4~(Th) Cse Conference(November 3,2007,Yangzhou)

Journal of Electrochemistry

No abstract provided.


Molten Salt Systems And The New Developments For The Application Of Molten Salts, Peng Liu, Ye-Xiang Tong, Qi-Qin Yang Nov 2007

Molten Salt Systems And The New Developments For The Application Of Molten Salts, Peng Liu, Ye-Xiang Tong, Qi-Qin Yang

Journal of Electrochemistry

The general situation of molten salt systems since 21 century are presented.The development of room temperature molten salts are emphasized.Applications of molten salts to the areas of preparating alloys and functional materials;batteries and capacitors;analysis and separation;use as reaction media and catalyzers;environmental protection have good prospect.In order to continually develop the molten salt system,it is necessary further to know the properties of molten salts and relevant theories,as well as exploiting the new methods and novel systems of synthesizing molten salts.


A Circular On The 26~(Th) Ccs Congress(July 13~16,2008.Tianjin,China) Nov 2007

A Circular On The 26~(Th) Ccs Congress(July 13~16,2008.Tianjin,China)

Journal of Electrochemistry

No abstract provided.


Contour Based 3d Biological Image Reconstruction And Partial Retrieval, Yong Li Nov 2007

Contour Based 3d Biological Image Reconstruction And Partial Retrieval, Yong Li

Computer Science Dissertations

Image segmentation is one of the most difficult tasks in image processing. Segmentation algorithms are generally based on searching a region where pixels share similar gray level intensity and satisfy a set of defined criteria. However, the segmented region cannot be used directly for partial image retrieval. In this dissertation, a Contour Based Image Structure (CBIS) model is introduced. In this model, images are divided into several objects defined by their bounding contours. The bounding contour structure allows individual object extraction, and partial object matching and retrieval from a standard CBIS image structure. The CBIS model allows the representation of …


Inference For Cox's Regression Model Via A New Version Of Empirical Likelihood, Ali Jinnah Nov 2007

Inference For Cox's Regression Model Via A New Version Of Empirical Likelihood, Ali Jinnah

Mathematics Theses

Cox Proportional Hazard Model is one of the most popular tools used in the study of Survival Analysis. Empirical Likelihood (EL) method has been used to study the Cox Proportional Hazard Model. In recent work by Qin and Jing (2001), empirical likelihood based confidence region is constructed with the assumption that the baseline hazard function is known. However, in Cox’s regression model the baseline hazard function is unspecified. In this thesis, we re-formulate empirical likelihood for the vector of regression parameters by estimating the baseline hazard function. The EL confidence regions are obtained accordingly. In addition, Adjusted Empirical Likelihood (AEL) …


The Exponential Function Of Matrices, Nathalie Nicholle Smalls Nov 2007

The Exponential Function Of Matrices, Nathalie Nicholle Smalls

Mathematics Theses

The matrix exponential is a very important subclass of functions of matrices that has been studied extensively in the last 50 years. In this thesis, we discuss some of the more common matrix functions and their general properties, and we specifically explore the matrix exponential. In principle, the matrix exponential could be computed in many ways. In practice, some of the methods are preferable to others, but none are completely satisfactory. Computations of the matrix exponential using Taylor Series, Scaling and Squaring, Eigenvectors, and the Schur Decomposition methods are provided.


Construction Of A Calcium Matter-Wave Interferometer, Christopher Joseph Erickson Nov 2007

Construction Of A Calcium Matter-Wave Interferometer, Christopher Joseph Erickson

Theses and Dissertations

I describe the construction of a calcium matter-wave interferometer. The interferometer is based on a Ramsey-Borde scheme, and uses a thermal beam of atoms excited by an optical-frequency transition in calcium. In our experiment four pi/2 pulses of light are delivered to the atoms, which split and recombine the wave functions of the atoms. Our experimental design minimizes first-order Doppler shifts, and allows for the cancellation of systematic errors including phase shifts due to rotation and acceleration. I describe the individual components of the interferometer and its assembly. The requirements for the electronics used in the experiment as well as …


Preheating In Derivatively-Coupled Inflation Models, Christian Armendariz-Picon, Mark Trodden, Eric J. West Nov 2007

Preheating In Derivatively-Coupled Inflation Models, Christian Armendariz-Picon, Mark Trodden, Eric J. West

Physics - All Scholarship

We study preheating in theories where the inflaton couples derivatively to scalar and gauge fields. Such couplings may dominate in natural models of inflation, in which the flatness of the inflaton potential is related to an approximate shift symmetry of the inflaton. We compare our results with previously studied models with non-derivative couplings. For sufficiently heavy scalar matter, parametric resonance is ineffective in reheating the universe, because the couplings of the inflaton to matter are very weak. If scalar matter fields are light, derivative couplings lead to a mild long-wavelength instability that drives matter fields to non-zero expectation values. In …


Longitudinal Data With Follow-Up Truncated By Death: Finding A Match Between Analysis Method And Research Aims, Brenda Kurland, Laura Lee Johnson, Paula Diehr Nov 2007

Longitudinal Data With Follow-Up Truncated By Death: Finding A Match Between Analysis Method And Research Aims, Brenda Kurland, Laura Lee Johnson, Paula Diehr

UW Biostatistics Working Paper Series

Diverse analysis approaches have been proposed to distinguish data missing due to death from nonresponse, and to summarize trajectories of longitudinal data truncated by death. We demonstrate how these analysis approaches arise from factorizations of the distribution of longitudinal data and survival information. Models are illustrated using hypothetical data examples (cognitive functioning in older adults, and quality of life under hospice care) and up to 10 annual assessments of longitudinal cognitive functioning data for 3814 participants in an observational study. For unconditional models, deaths do not occur, deaths are independent of the longitudinal response, or the unconditional longitudinal response averages …


Ground Water Level Measurements In Selected Boreholes Near The Site Of The Proposed Repository, H. Scott Page, Klaus J. Stetzenbach, Amy J. Smiecinski Nov 2007

Ground Water Level Measurements In Selected Boreholes Near The Site Of The Proposed Repository, H. Scott Page, Klaus J. Stetzenbach, Amy J. Smiecinski

Publications (YM)

The purpose of this report is to summarize the work and present conclusions of Project Activity Task FY-04-005 conducted under DE-FC28-04RW12232 between the U.S. Department of Energy and the Nevada System of Higher Education (NSHE). The work was conducted in the Harry Reid Center for Environmental Studies of the University of Nevada – Las Vegas from Oct 1, 2003 to Sept 30, 2007.


Computational Intelligence Based Classifier Fusion Models For Biomedical Classification Applications, Xiujuan Chen Nov 2007

Computational Intelligence Based Classifier Fusion Models For Biomedical Classification Applications, Xiujuan Chen

Computer Science Dissertations

The generalization abilities of machine learning algorithms often depend on the algorithms’ initialization, parameter settings, training sets, or feature selections. For instance, SVM classifier performance largely relies on whether the selected kernel functions are suitable for real application data. To enhance the performance of individual classifiers, this dissertation proposes classifier fusion models using computational intelligence knowledge to combine different classifiers. The first fusion model called T1FFSVM combines multiple SVM classifiers through constructing a fuzzy logic system. T1FFSVM can be improved by tuning the fuzzy membership functions of linguistic variables using genetic algorithms. The improved model is called GFFSVM. To better …


A Contextualized Web-Based Learning Environments For Devs Models, Inthira Srivrunyoo Nov 2007

A Contextualized Web-Based Learning Environments For Devs Models, Inthira Srivrunyoo

Computer Science Theses

With the advance in applying technology in education, the traditional lecture-driven teaching style is gradually replaced by a more active teaching style where the students play a more active rule in the learning process. In this paper we introduce a new initiative to provide a suite of online tools for learning DEVS model. The uniqueness of this tutorial project is the integration of information technology and multimedia into education through the development of an interactive tutorial and the characteristic of contextualized learning. The tutorial teaches students about the basic aspects of discrete event system and simulation. The interactive tutorial fully …


New Ways To Collect Data In The Antarctic, Walker O. Smith, Vernon Asper Nov 2007

New Ways To Collect Data In The Antarctic, Walker O. Smith, Vernon Asper

Faculty Publications

Conducting Antarctic research is challenging. Not only is the environment difficult, given low temperatures, high winds, and ice cover, but also the availability of sampling platforms is limited. The U.S. National Science Foundation has only two vessels that can routinely operate in ice‐covered waters, the research vessel/icebreaker N.B. Palmer and the Antarctic research support vessel L.M. Gould. The restricted availability of vessels makes research operations difficult to schedule, especially during austral spring and summer. Traditional sampling methods (those confined to ships and moorings) have provided insights into distributions and processes in the Southern Ocean, but new research questions require new …


Improving Feature Selection Techniques For Machine Learning, Feng Tan Nov 2007

Improving Feature Selection Techniques For Machine Learning, Feng Tan

Computer Science Dissertations

As a commonly used technique in data preprocessing for machine learning, feature selection identifies important features and removes irrelevant, redundant or noise features to reduce the dimensionality of feature space. It improves efficiency, accuracy and comprehensibility of the models built by learning algorithms. Feature selection techniques have been widely employed in a variety of applications, such as genomic analysis, information retrieval, and text categorization. Researchers have introduced many feature selection algorithms with different selection criteria. However, it has been discovered that no single criterion is best for all applications. We proposed a hybrid feature selection framework called based on genetic …


Ieee 802.15.4 Mac Protocol Study And Improvement, Liang Cheng Nov 2007

Ieee 802.15.4 Mac Protocol Study And Improvement, Liang Cheng

Computer Science Dissertations

IEEE 802.15.4 is a standard used for low rate personal area networks (PANs). It offers device level connectivity in applications with limited ower and relaxed throughput requirements. Devices with IEEE 802.15.4 technology can be used in many potential applications, such as home networking, industry/environments monitoring, healthcare equipments, etc, due to its extremely low power features. Although the superframe beacons play the key role in synchronizing channel access in IEEE 802.15.4, they are sources for energy inefficiency. This research focuses on exploring how to optimize the beacons, and designing novel schemes to distribute the information that are supposed to be delivered …


Prediction Of Oxidation States Of Cysteines And Disulphide Connectivity, Aiguo Du Nov 2007

Prediction Of Oxidation States Of Cysteines And Disulphide Connectivity, Aiguo Du

Computer Science Dissertations

Knowledge on cysteine oxidation state and disulfide bond connectivity is of great importance to protein chemistry and 3-D structures. This research is aimed at finding the most relevant features in prediction of cysteines oxidation states and the disulfide bonds connectivity of proteins. Models predicting the oxidation states of cysteines are developed with machine learning techniques such as Support Vector Machines (SVMs) and Associative Neural Networks (ASNNs). A record high prediction accuracy of oxidation state, 95%, is achieved by incorporating the oxidation states of N-terminus cysteines, flanking sequences of cysteines and global information on the protein chain (number of cysteines, length …


Evaluation Of Striped Bass Stocks In Virginia : Monitoring And Tagging Studies, 2004-2008 - Annual Report 1 September 2006 - 31 August 2007, Philip W. Sadler, John M. Hoenig, Robert E. Harris, Rebecca J. Wilk, Lydia M. Goins Nov 2007

Evaluation Of Striped Bass Stocks In Virginia : Monitoring And Tagging Studies, 2004-2008 - Annual Report 1 September 2006 - 31 August 2007, Philip W. Sadler, John M. Hoenig, Robert E. Harris, Rebecca J. Wilk, Lydia M. Goins

Reports

This report presents the results of striped bass (Morone saxatilis) tagging and monitoring activities in Virginia during the period 1 September 2006 through 31 August 2007. It includes an assessment of the biological characteristics of striped bass taken from the 2007 spring spawning run, estimates of annual survival and fishing mortality based on annual spring tagging, and the preliminary results of the fall 2006 study that documents the prevalence of mycobacterial infections of striped bass in Chesapeake Bay. The information contained in this report is required by the Atlantic States Marine Fisheries Commission and is used to implement a coordinated …


Correction: Using Participatory Design To Develop (Public) Health Decision Support Systems Through Gis, S. Michelle Driedger, Anita Kothari, Jason Morrison, Michael Sawada, Eric J. Crighton, Ian D. Graham Nov 2007

Correction: Using Participatory Design To Develop (Public) Health Decision Support Systems Through Gis, S. Michelle Driedger, Anita Kothari, Jason Morrison, Michael Sawada, Eric J. Crighton, Ian D. Graham

Anita Kothari

Background: Organizations that collect substantial data for decision-making purposes are often characterized as being 'data rich' but 'information poor'. Maps and mapping tools can be very useful for research transfer in converting locally collected data into information. Challenges involved in incorporating GIS applications into the decision-making process within the non-profit (public) health sector include a lack of financial resources for software acquisition and training for nonspecialists to use such tools. This on-going project has two primary phases. This paper critically reflects on Phase 1: the participatory design (PD) process of developing a collaborative web-based GIS tool.

Methods: A case study …


Nebraska Record Fish Nov 2007

Nebraska Record Fish

Nebraska Game and Parks Commission: Publications

Nebraska Record Fish:
Rod and Reel
Bow and Arrow
Underwater Powered Spearing
Surface Spearfishing


1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev Nov 2007

1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev

Faculty Publications

The title compound, C72F36, is one of four isomers of C60(CF3)12 for which crystal structures have been obtained. The fullerene mol­ecule has an idealized Ih C60 core with the 12 CF3 groups arranged in an asymmetric fashion on two ribbons of edge-sharing C6(CF3)2 hexa­gons, a parametaparaparaparametapara ribbon and a parametapara ribbon, giving an overall pmp 3 mp,pmp structure. There are no cage Csp 3 …