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2007

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Articles 361 - 390 of 6758

Full-Text Articles in Physical Sciences and Mathematics

Competition In Modular Clusters, Carliss Y. Baldwin, C. Jason Woodard Dec 2007

Competition In Modular Clusters, Carliss Y. Baldwin, C. Jason Woodard

Research Collection School Of Computing and Information Systems

The last twenty years have witnessed the rise of disaggregated “clusters,” “networks,” or “ecosystems” of firms. In these clusters the activities of R&D, product design, production, distribution, and system integration may be split up among hundreds or even thousands of firms. Different firms will design and produce the different components of a complex artifact (like the processor, peripherals, and software of a computer system), and different firms will specialize in different stages of a complex production process. This paper considers the pricing behavior and profitability of these so-called modular clusters. In particular, we investigate a possibility hinted at in prior …

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Uniform Weighted Compact / Non-Compact Schemes For Shock / Boundary Layer Interaction, Peng Xie Dec 2007

Uniform Weighted Compact / Non-Compact Schemes For Shock / Boundary Layer Interaction, Peng Xie

Mathematics Dissertations

The critical problem of CFD is perhaps an accurate approximation of derivatives for a given discrete data set. Based on our previous work on the weighted compact scheme (WCS), a uniform weighted compact / non-compact scheme (UWCNC) has been developed. Similar to WENO, three high order candidates, left, right, and central, are constructed by using Hermite polynomials. According to the smoothness, three weights are derived and assigned to each candidate. The weights will lead the scheme to be upwind-biased when approaching the shock or other discontinuities but quickly becomes central, compact, and of high order just off the shock. Therefore, …

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Study Of Multiple Impacts Of A Rigid Body With A Flat Surface, Florin Vasile Badiu Dec 2007

Study Of Multiple Impacts Of A Rigid Body With A Flat Surface, Florin Vasile Badiu

Mathematics Dissertations

Both analytical and numerical results are presented for two rigid body problems: a rod colliding with the ground, and a rigid thin plate colliding with the ground. The study of the succession of impacts of the rod with the ground confirms results from literature, and explores new cases. Numerical simulations can provide results in the study of the clattering impacts of a 3D body colliding with the ground. For a simplification of the analytical calculations, a rectangular plate without thickness is studied. In this case, a comparison between the numerical method, which is a continuous contact method, and the analytical …

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Zinc Cysteine Active Sites Of Metalloproteins: A Density Functional Theory And X-Ray Absorption Fine Structure Study, N. Dimakis, Mohammed Junaid Farooqi, Emily Sofia Garza, Grant Bunker Dec 2007

Zinc Cysteine Active Sites Of Metalloproteins: A Density Functional Theory And X-Ray Absorption Fine Structure Study, N. Dimakis, Mohammed Junaid Farooqi, Emily Sofia Garza, Grant Bunker

Physics and Astronomy Faculty Publications and Presentations

Density functional theory (DFT) and x-ray absorption fine structure (XAFS) spectroscopy are complementary tools for the biophysical study of active sites in metalloproteins. DFT is used to compute XAFS multiple scattering Debye Waller factors, which are then employed in genetic algorithm-based fitting process to obtain a global fit to the XAFS in the space of fitting parameters. Zn-Cys sites, which serve important functions as transcriptional switches in Zn finger proteins and matrix metalloproteinases, previously have proven intractable by this method; here these limitations are removed. In this work we evaluate optimal DFT nonlocal functionals and basis sets for determining optimal …

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What Is Rcu, Fundamentally?, Paul E. Mckenney, Jonathan Walpole Dec 2007

What Is Rcu, Fundamentally?, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Read-copy update (RCU) is a synchronization mechanism that was added to the Linux kernel in October of 2002. RCU achieves scalability improvements by allowing reads to occur concurrently with updates. In contrast with conventional locking primitives that ensure mutual exclusion among concurrent threads regardless of whether they be readers or updaters, or with reader-writer locks that allow concurrent reads but not in the presence of updates, RCU supports concurrency between a single updater and multiple readers. RCU ensures that reads are coherent by maintaining multiple versions of objects and ensuring that they are not freed up until all pre-existing read-side …

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The Virginia Clean Marina Guidebook, Virginia Clean Marina Program, Virginia Institute Of Marine Science Dec 2007

The Virginia Clean Marina Guidebook, Virginia Clean Marina Program, Virginia Institute Of Marine Science

Reports

No abstract provided.

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Using Seeds To Propagate And Restore Vallisneria Americana Michaux (Wild Celery) In The Chesapeake Bay, Kenneth A. Moore, Jesse C. Jarvis Dec 2007

Using Seeds To Propagate And Restore Vallisneria Americana Michaux (Wild Celery) In The Chesapeake Bay, Kenneth A. Moore, Jesse C. Jarvis

Reports

Loss of submerged aquatic vegetation (SAV) has been significant in many coastal and estuarine systems such as the Chesapeake Bay where SAV die-offs have been observed in marine, brackish, and freshwater SAV communities (Orth and Moore 1983). Large-scale replanting using whole plants can be cost-prohibitive, and the use of plants taken from wild populations for propagule supply may not be possible or desirable. The use of SAV seeds for restoration has been increasingly demonstrated to be an effective method for replanting large areas of bottom, especially for marine species such as eelgrass, Zostera marina (Pickerell et al. 2005; Orth et …

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Development Of A Nontidal Wetland Inventory And Monitoring Strategy For Virginia – Completion Of Phase Ii (Coastal Plain And Piedmont Physiographic Provinces), Center For Coastal Resources Management, Virginia Institute Of Marine Science Dec 2007

Development Of A Nontidal Wetland Inventory And Monitoring Strategy For Virginia – Completion Of Phase Ii (Coastal Plain And Piedmont Physiographic Provinces), Center For Coastal Resources Management, Virginia Institute Of Marine Science

Reports

No abstract provided.

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A Unified Interdisciplinary Theory Of Open Source Culture And Entertainment, Jerald Hughes, Karl Reiner Lang, Eric K. Clemons, Robert J. Kauffman Dec 2007

A Unified Interdisciplinary Theory Of Open Source Culture And Entertainment, Jerald Hughes, Karl Reiner Lang, Eric K. Clemons, Robert J. Kauffman

Research Collection School Of Computing and Information Systems

Digital technologies are profoundly transforming the production and consumption of culture and entertainment products. The emerging digital re-mix culture is an open source approach where content products in the arts and entertainment industries are increasingly rearranged, manipulated, and extended in the process of creating new works. This article offers a unified description of the tools and techniques that led to the development of the open source culture and that enable the processes which promote re-use of previously recorded materials. It then lays out the incentives and forces that either promote or inhibit the development, distribution, and consumption of modified cultural …

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Preventing Location-Based Identity Inference In Anonymous Spatial Queries, Panos Kalnis, Gabriel Ghinita, Kyriakos Mouratidis, Dimitris Papadias Dec 2007

Preventing Location-Based Identity Inference In Anonymous Spatial Queries, Panos Kalnis, Gabriel Ghinita, Kyriakos Mouratidis, Dimitris Papadias

Research Collection School Of Computing and Information Systems

The increasing trend of embedding positioning capabilities (for example, GPS) in mobile devices facilitates the widespread use of location-based services. For such applications to succeed, privacy and confidentiality are essential. Existing privacy-enhancing techniques rely on encryption to safeguard communication channels, and on pseudonyms to protect user identities. Nevertheless, the query contents may disclose the physical location of the user. In this paper, we present a framework for preventing location-based identity inference of users who issue spatial queries to location-based services. We propose transformations based on the well-established K-anonymity concept to compute exact answers for range and nearest neighbor search, without …

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A Fast Image Super-Resolution Algorithm Using An Adaptive Wiener Filter, Russell C. Hardie Dec 2007

A Fast Image Super-Resolution Algorithm Using An Adaptive Wiener Filter, Russell C. Hardie

Electrical and Computer Engineering Faculty Publications

A computationally simple super-resolution algorithm using a type of adaptive Wiener filter is proposed. The algorithm produces an improved resolution image from a sequence of low-resolution (LR) video frames with overlapping field of view. The algorithm uses subpixel registration to position each LR pixel value on a common spatial grid that is referenced to the average position of the input frames. The positions of the LR pixels are not quantized to a finite grid as with some previous techniques. The output high-resolution (HR) pixels are obtained using a weighted sum of LR pixels in a local moving window. Using a …

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Design Construction And Use Of A Thermomechanical Detwinning Apparatus: Detwinning Of Orthorhombic Nb2bacu2o3, Chad J. Bircher Dec 2007

Design Construction And Use Of A Thermomechanical Detwinning Apparatus: Detwinning Of Orthorhombic Nb2bacu2o3, Chad J. Bircher

Masters Theses

In this thesis I will describe a device designed and built for thermo- mechanically detwinning crystals. Twinning is a process in which a crys- talline structrure with two different axes of nearly equal length alternate directions throughout the material, effectively generating a single bulk material with two or more distinct internal crystals. This structure defect can lead to many other effects in the crystal, and it is useful to elimi- nate twinning in many materials in order to determine which properties are fundamental properties of the crystal, and which properties are ar- tifacts of the structural imperfections. The apparatus described …

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Reduction Of Human Factors-Related Accidents During The Flight Test Of Homebuilt Aircraft Through The Application Of Professional Flight Test Practices, Justin Samuel Garr Dec 2007

Reduction Of Human Factors-Related Accidents During The Flight Test Of Homebuilt Aircraft Through The Application Of Professional Flight Test Practices, Justin Samuel Garr

Masters Theses

Homebuilt aircraft have a high accident rate during the flight test period, particularly during their first and second flights. For the 2002-2004 period, over 1.0% of homebuilt aircraft were involved in an accident on their first flight, and 3.3% were involved in accidents in the first 40 hours of operation. Untrained, low time in aircraft type amateur flight test participants, unorthodox flight test procedures, and lack of clear guidance as to who should and how to conduct safe and effective flight test lead to unsafe conditions and the accident statistics support this hypothesis. In the accidents analyzed, lack of experience …

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Characterization Of The Temperature Dependence Of Optical Components In A Cryo-Vacuum Chamber Used For Space Sensor Testing, Jesse M. Labello Dec 2007

Characterization Of The Temperature Dependence Of Optical Components In A Cryo-Vacuum Chamber Used For Space Sensor Testing, Jesse M. Labello

Masters Theses

The space sensor cryo-vacuum chambers at Arnold Air Force Base are world class sensor characterization and calibration facilities. The chambers provide a simulated deep space background and accurate infrared projections. Several large optical systems are used within the chambers to accomplish this. Calibration of the chambers requires the use of a database of the measured optical properties of these components to simulate the output. However, as the information in the database is room temperature information and the chambers run near 20K, some discrepancies exist between the actual output and the model output. The purpose of this work is to translate …

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Major And Trace-Element Chemistry Of Minerals In Lithologies A And B In Martian Meteorite Eeta79001: Petrogenesis Revisited, Michael Joseph Mellin Dec 2007

Major And Trace-Element Chemistry Of Minerals In Lithologies A And B In Martian Meteorite Eeta79001: Petrogenesis Revisited, Michael Joseph Mellin

Masters Theses

EETA79001 is a unique shergottite composed of two mafic lithologies (termed LithA and LithB) that are separated by an igneous contact. Both lithologies have basaltic compositions; however, LithA contains megacrysts of olivine, orthopyroxenes, and chromite whereas LithB does not; also, LithA is finer-grained than LithB. Currently, the literature is in disagreement regarding the formation of this unique meteorite, especially regarding LithA. Different formational theories (e.g. fractional crystallization, magma mixing, assimilation, and impact melting) have their own constraints (chemical, thermal, or petrographic). This study uses petrographic observations combined with major- and trace- element compositions within minerals to investigate the petrogenesis of …

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Bacterial Source Tracking In An Eastern Tennessee Stream Using Bacteroides Host Associated Real-Time Polymerase Chain Reaction Assays, Ryan Michael Ragsdale Dec 2007

Bacterial Source Tracking In An Eastern Tennessee Stream Using Bacteroides Host Associated Real-Time Polymerase Chain Reaction Assays, Ryan Michael Ragsdale

Masters Theses

A bacterial source tracking study using Bacteroides host associated real-time PCR assays was performed to determine the sources of fecal contamination in Pond Creek (HUC 06010201013). Pond Creek, located in the Ridge and Valley physiographic region in Eastern Tennessee, is a 303(d) listed stream that fails to meet water quality standards for pathogens. Water samples and discharge were measured monthly at eight locations from November 2005 to November 2006. Grab samples were analyzed for several chemical parameters and for microbial fecal indicator organisms, namely Bacteroides spp., Escherichia coli, and Enterococcus. The objectives of the study were to quantify total, …

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Stream Restoration Assessment Of Abrams Creek In The Great Smoky Mountains National Park: Management Implications And Comparison Of Empirical And Analytical Physical Assessment Approaches, Daniel L. Carter Dec 2007

Stream Restoration Assessment Of Abrams Creek In The Great Smoky Mountains National Park: Management Implications And Comparison Of Empirical And Analytical Physical Assessment Approaches, Daniel L. Carter

Masters Theses

Natural resource managers in the Great Smoky Mountains National Park requested the assistance of the University of Tennessee Department of Civil and Environmental Engineering to assess Abrams Creek for potential stream restoration needs. A presumed, unstable study reach and a stable reference reach were identified on Abrams Creek in Cades Cove. Chemical, biological and physical assessments were completed on Abrams Creek in order to evaluate ecological health and channel stability of the stream. Water quality and ecological (fish and habitat surveys) data acquired by National Park Service, Tennessee Valley Authority and the University of Tennessee were assessed. The physical assessment …

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Performance Of Sills: St. Mary’S City, St. Mary’S River, Maryland, C. Scott Hardaway Jr., W. G. Reay, Jian Shen, Scott Lerberg, Donna A. Milligan, Christine A. Wilcox, Kevin P. O'Brien Dec 2007

Performance Of Sills: St. Mary’S City, St. Mary’S River, Maryland, C. Scott Hardaway Jr., W. G. Reay, Jian Shen, Scott Lerberg, Donna A. Milligan, Christine A. Wilcox, Kevin P. O'Brien

Reports

Living shorelines represent a shoreline management option that combines various erosion control methodologies and/or structures while at the same time restoring or preserving natural shoreline vegetation communities. A common living shoreline design in Chesapeake Bay includes a low offshore rock sill to absorb wave energy with an emergent wetland landward of the sill to enhance erosion control, provide critical habitat, and improve water quality condition. This study is part of a larger, ongoing project to (1) evaluate erosion control effectiveness and the sustainability of offshore sill and fringing marsh design and structure, (2) evaluate ecological services (e.g., habitat value, water …

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An Analysis Of The Environmental Content Of Las Vegas Strip Hotels, Andrew M. Levey Dec 2007

An Analysis Of The Environmental Content Of Las Vegas Strip Hotels, Andrew M. Levey

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study examines the environmental content of hotel properties websites. The central question of this study is whether Las Vegas Strip properties have gone green, or plan to go green. Thus, the purpose of this paper is to examine the frequency of the environmental content of twenty-three Las Vegas Strip hotels’ websites as well as five upcoming hotel projects and one hotel expansion project on the Strip. The twenty-eight hotels are all located along Las Vegas Boulevard, also known as the Strip. All properties examined have over two thousand rooms each. The goal is to determine how prevalent and important …

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A Study Of The Relationship Between American Evangelicals And Human Rights, Amy Rachel Timmons Stumpf Dec 2007

A Study Of The Relationship Between American Evangelicals And Human Rights, Amy Rachel Timmons Stumpf

Loma Linda University Electronic Theses, Dissertations & Projects

Human rights violations and abuses affect every region of the globe. The most recent Amnesty International Annual Report details violations in 149 countries. While there are no simple solutions to a problem of this magnitude and complexity, the support of powerful social groups can help in providing relief to the victims, pressure on abusive governments, legal consequences for abusers, and other resources in combating the violence that seems to chronically plague over our world. One of the most powerful groups, with tremendous social capital, is American evangelicals. Evangelicalism, even given the loose and informal organizational structures, is one of the …

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The Opacity Of Spiral Galaxy Disks. Viii. Structure Of The Cold Ism., Benne W. Holwerda, B. Draine, K. D. Gordon, R. A. Gonzalez, D. Calzetti, M. Thornley, B. Buckalew, Ronald J. Allen, P C. Van Der Kruit Dec 2007

The Opacity Of Spiral Galaxy Disks. Viii. Structure Of The Cold Ism., Benne W. Holwerda, B. Draine, K. D. Gordon, R. A. Gonzalez, D. Calzetti, M. Thornley, B. Buckalew, Ronald J. Allen, P C. Van Der Kruit

Faculty and Staff Scholarship

The quantity of dust in a spiral disk can be estimated using the dust’s typical emission or the extinction of a known source. In this paper we compare two techniques, one based on emission and one on absorption, applied to sections of 14 disk galaxies. The two measurements reflect, respectively, the average and apparent optical depth of a disk section. Hence, they depend differently on the average number and optical depth of ISM structures in the disk. The small-scale geometry of the cold ISM is critical for accurate models of the overall energy budget of spiral disks. ISM geometry, relative …

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Spiral Disk Opacity From Occulting Galaxy Pairs In The Sloan Digital Sky Survey., Benne W. Holwerda, W. C. Keel, A. Bolton Dec 2007

Spiral Disk Opacity From Occulting Galaxy Pairs In The Sloan Digital Sky Survey., Benne W. Holwerda, W. C. Keel, A. Bolton

Faculty and Staff Scholarship

A spiral galaxy partially overlapping a more distant elliptical offers a unique opportunity to measure the dust extinction in the foreground spiral. From the Sloan Digital Sky Survey (SDSS) DR4 spectroscopic sample, we selected 83 occulting galaxy pairs and measured disk opacity over the redshift range z ¼ 0:0Y0:2 with the goal of determining the recent evolution of disk dust opacity. The enrichment of the ISM changes over the lifetime of a disk, and it is reasonable to expect the dust extinction properties of spiral disks as a whole to change over their lifetime. When they do, the change will …

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A Lower Estimate For The Norm Of The Kerzman-Stein Operator, Michael Bolt Dec 2007

A Lower Estimate For The Norm Of The Kerzman-Stein Operator, Michael Bolt

University Faculty Publications and Creative Works

We establish an elementary lower estimate for the norm of the Kerzman-Stein operator for a smooth, bounded domain. The estimate involves the boundary length and logarithmic capacity. The estimate is tested on model domains for which the norm is known explicitly. It is shown that the estimate is sharp for an annulus and a strip, and is asymptotically sharp for an ellipse and a wedge. © 2007 Rocky Mountain Mathematics Consortium.

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Can Collective Action And Capacity Building Reduce Vulnerability Among Settled Pastoralists?, D. Layne Coppock, Solomon Desta, Getachew Gebru, Seyoum Tezera Dec 2007

Can Collective Action And Capacity Building Reduce Vulnerability Among Settled Pastoralists?, D. Layne Coppock, Solomon Desta, Getachew Gebru, Seyoum Tezera

Environment and Society Faculty Publications

In 2001 PARIMA and her partners began to create collective-action groups among illiterate, settled pastoralists in southern Ethiopia. These groups—dominated by women—focused on savings-led microfinance, small business, and livestock marketing to increase incomes and diversify livelihoods. Fifty-nine groups with over 2,100 members were formed using intensive capacity- building methods. After six years we wanted to compare group members with their neighbors who never participated in the PARIMA program. We surveyed 180 individuals from groups and paired control (traditional) communities. Respondents were asked to assess the extent that they perceived positive, negative, or no change in their lives over the past …

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Formation Of Peptide Nanospheres And Nanofibrils By Metal Coordination, Mikhail V. Tsurkan, Michael Y. Ogawa Dec 2007

Formation Of Peptide Nanospheres And Nanofibrils By Metal Coordination, Mikhail V. Tsurkan, Michael Y. Ogawa

Chemistry Faculty Publications

Two amphipathic polypeptides were coordinated to the cis positions of a square planar Pt(II) complex in order to provide the metal center with two noncovalent oligomerization domains. This resulted in the formation of new metal-peptide nanoassemblies which are shown to exist as nanometer-sized spheres and fibrils. Construction of these assemblies was based on the 30-residue polypeptide AQ-Pal14 which was designed for its ability to self-assemble into the common protein oligomerization motif of a noncovalent coiled-coil, and modified to contain a metal-binding 4-pyridylalanine residue at its surface. When AQ-Pal14 was reacted with Pt(en)(NO3)(2), a new metal-peptide complex was formed in which …

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Excited-State Equilibration Over 30 Angstrom In A Platinum(Ii) Quinolinolate-Bridge-Platinum(Ii) Porphyrin Complex, Victor A. Montes, Michael A. J. Rodgers, Pavel Anzenbacher Jr. Dec 2007

Excited-State Equilibration Over 30 Angstrom In A Platinum(Ii) Quinolinolate-Bridge-Platinum(Ii) Porphyrin Complex, Victor A. Montes, Michael A. J. Rodgers, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Long-range triplet excited-state equilibration occurs over a nanometric distance between platinum(II) 8-quinolinolate ((3)Ptq(2) = 1.87 eV) and platinum(II) tetraphenylporphyrin ((PtTPP)-Pt-3 = 1.89 eV). The equilibrium is mediated by a fluorene-thiophene-fluorene bridge ((FTF)-F-3 = 1.92 eV) and is characterized by a double-exponential decay (tau(1) = 39 +/- 4 ps; tau(2) = 351 +/- 15 ps) that suggests the participation of three separate excited states : (3)Ptq(2), (FTF)-F-3, and 3PtTPP, respectively. Numerical simulation of the dual equilibrium allowed for estimation of the individual rate constants for each of the reversible steps (k(ET) = 3.9 x 10(9)-4.1 x 10(10) s(-1)). As a result …

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A Unit Of Information-Based Content Adaptation Method For Improving Web Content Accessibility In The Mobile Internet, Stephen Yang, Jia Zhang, Rick Chen, Norman Shao Nov 2007

A Unit Of Information-Based Content Adaptation Method For Improving Web Content Accessibility In The Mobile Internet, Stephen Yang, Jia Zhang, Rick Chen, Norman Shao

Jia Zhang

No abstract provided.

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Exact One-Sided Confidence Limits For The Difference Between Two Correlated Proportions, Chris Lloyd, Max V. Moldovan Nov 2007

Exact One-Sided Confidence Limits For The Difference Between Two Correlated Proportions, Chris Lloyd, Max V. Moldovan

Chris J. Lloyd

We construct exact and optimal one-sided upper and lower confidence bounds for the difference between two probabilities based on matched binary pairs using well-established optimality theory of Buehler (1957). Starting with five different approximate loer and upper limits, we adjust them to have coverage probability exactly equal to the desired nominal level and then compare the resulting exact limits by their mean size. Exact limits based on the signed root likelihood ratio statistic are preferred and recommended for practical use.

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Roles And Responsiblities For Vicses In Flood Education (Report), Neil Dufty Nov 2007

Roles And Responsiblities For Vicses In Flood Education (Report), Neil Dufty

Neil Dufty

No abstract provided.

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Trends In Uspto Office Actions, Ron D. Katznelson Nov 2007

Trends In Uspto Office Actions, Ron D. Katznelson

Ron D. Katznelson

No abstract provided.

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