Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Other

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type

Articles 1681 - 1710 of 2496

Full-Text Articles in Physical Sciences and Mathematics

Dynamic Cache Reconfiguration For Energy Optimization In Chip Multiprocessors, Gaurav Puri Jan 2012

Dynamic Cache Reconfiguration For Energy Optimization In Chip Multiprocessors, Gaurav Puri

Computer Science and Engineering Theses

Cache reconfiguration for chip multiprocessors (CMP) in order to reduce energy consumption is a challenging research problem. This thesis presents a dynamic scheme for level one cache design where the processing core can dynamically switch to a lower energy configuration. The proposed scheme is based on a heuristic that can either be executed as part of the firmware or implemented in hardware with very low additional overhead. The heuristic functions periodically after a pre-defined fixed interval for each processing core. The heuristic first examines the statistics calculated over the previous intervals and then switches the cache to an improved configuration …

Go to article

Querying Entity-Relationship Graphs By Example Tuples: Experimental Evaluation And User Study, Mahesh Gupta Jan 2012

Querying Entity-Relationship Graphs By Example Tuples: Experimental Evaluation And User Study, Mahesh Gupta

Computer Science and Engineering Theses

The World Wide Web today has evolved into a rich repository of entities where many knowledge bases containing entity-related information are directly available. Such knowledge bases are often in the form of entity-relationship graphs. To query entity-relationship graphs, users need to provide input entities, attributes and relationships by complex query graphs. To improve the usability of graph database systems, we study a novel mechanism that queriesentity-relationship graphs by example tuples. It allows users to express a query in the form of one or more tuples consisting of entities. The underlying query system automatically builds aquery graph based on the example …

Go to article

Defect Studies In Cu-Based P-Type Transparent Conducting Oxides, Fnu Ameena Jan 2012

Defect Studies In Cu-Based P-Type Transparent Conducting Oxides, Fnu Ameena

Physics Dissertations

Among other intrinsic open-volume defects, copper vacancy (VCu) has been theoretically identified as the major acceptor in p-type Cu-based semiconducting transparent oxides, which has potential as low-cost photovoltaic absorbers in semi-transparent solar cells. A series of positron annihilation experiments with pure Cu, Cu2O, and CuO presented strong presence of VCu and its complexes in the copper oxides. The lifetime data also showed that the density of VCu was becoming higher as the oxidation state of Cu increased which was consistent with the decrease in the formation energy of VCu. Doppler broadening measurements further indicated that electrons with low momentum made …

Go to article

Selected Studies Of Celestial Dynamics And Habitability Of Extra Solar Planetary Systems, Billy Lee Quarles Jan 2012

Selected Studies Of Celestial Dynamics And Habitability Of Extra Solar Planetary Systems, Billy Lee Quarles

Physics Dissertations

Planetary science in various forms has become interwoven into human culture during all of known human history. The need and desire to expand our horizons has brought humans from basic forms of observation to the development of space satellites that have (in)directly observed other worlds. A major feat of this enterprise during the last half century has been the develop of numerical tools and theories to determine the orbital stability of multiple objects orbiting a central body. Two special cases of the gravitational N body problem (N = 3,4) have been investigated along with the development of a stability criterion …

Go to article

Silicon Carbide At Nanoscale: Finite Single-Walled To "Infinite" Multi-Walled Tubes, Kapil Adhikari Jan 2012

Silicon Carbide At Nanoscale: Finite Single-Walled To "Infinite" Multi-Walled Tubes, Kapil Adhikari

Physics Dissertations

A systematic ab initio study of silicon carbide (SiC) nanostructures, especially finite single-walled, infinite double- and multi-walled nanotubes and nanocones is presented. Electronic and structural properties of all these nanostructures have been calculated using hybrid density functionals (B3LYP and PBE0) as implemented in the GAUSSIAN 03/09 suite of software. The unusual dependence of band gap of silicon carbide nanotubes (SiCNT) has been explained as a direct consequence of curvature effect on the ionicity of the bonds. The study of fullerene hemisphere capped, finite SiC nanotubes indicates that the carbon-capped SiC nanotubes are energetically more preferred than silicon-capped finite or hydrogen …

Go to article

Quantum Modeling Of Dark Matter In Galactic Halos, Shane Charles Spivey Jan 2012

Quantum Modeling Of Dark Matter In Galactic Halos, Shane Charles Spivey

Physics Dissertations

Eighty years after its initial discovery, the nature of dark matter remains a mystery. Contrary to observational evidence, simulations of dark matter halos predict cuspy density profiles and an abundant population of dwarf galaxies. Increasingly refined measurements of the dark matter halos in galaxies reveal a large variety of halo shapes and sizes, and so far no universal profile has been able to incorporate them all. Among the numerous dark matter candidates, models of so-called quantum cold dark matter (QCDM) have the unique potential to address the many disparities between theory and observation.QCDM postulates that dark matter is composed primarily …

Go to article

Numerical Simulation Of The Base-Level Buffers And Buttresses Conceptual Model Of Fluvial Systems, Ronnie Tooyak Tingook Jan 2012

Numerical Simulation Of The Base-Level Buffers And Buttresses Conceptual Model Of Fluvial Systems, Ronnie Tooyak Tingook

Earth & Environmental Sciences Dissertations

A Buffer in fluvial stratigraphy is a potentiometric surface which defines either: a) the lowest possible depth to which streams will incise; or b) the maximum elevation to which aggradation will occur; together, these surfaces define a buffer zone. The buffer zone is tied down profile to a Buttress which defines base level for the system. A buttress shift, i.e., change in sea-level or shoreline-trajectory sensu (Catuneanu et al., 2009), will effect a change as to where the buffer zone exists for a fluvial system at a particular point in time. These terms were all introduced in (Holbrook et al., …

Go to article

The Impact Of Sprawl On Transportation Energy Copnsumption And Transportation Carbon Footprint In Large U.S. Cities, Leila Ahmadi Jan 2012

The Impact Of Sprawl On Transportation Energy Copnsumption And Transportation Carbon Footprint In Large U.S. Cities, Leila Ahmadi

Earth & Environmental Sciences Dissertations

Today, climate change and energy shortage are major concerns among scientists, politicians, and economists. For decades in the U.S., emphasis has been placed on improving energy efficiency through technological advances. However, most of these technologies are in the initial phases of development, while energy consumption continues to increase at a rapid pace. In order to solve this dilemma, there is a need to develop a faster and more effective approach for controlling the rates of energy consumption and demand. Transportation consumes more energy than other energy-dependent activities, such as those in the industrial, residential, and commercial sectors of the economy. …

Go to article

On-Road Measurement Of Nox And Co₂ Emissions From Biodiesel Produced From Different Feedstocks, Natchanok Pala-En Jan 2012

On-Road Measurement Of Nox And Co₂ Emissions From Biodiesel Produced From Different Feedstocks, Natchanok Pala-En

Earth & Environmental Sciences Dissertations

Biodiesel has generated increased interest in the US and elsewhere recently as an alternative to petroleum-derived diesel. Because it can be produced from domestic feedstocks such as soybeans, canola oil, and even recycled cooking oil, biodiesel can help reduce dependence on foreign petroleum. Due to its high oxygen content, biodiesel typically burns more completely than petroleum diesel, and thus has lower emissions of hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM). However, biodiesel may increase or decrease nitrogen oxide (NOx) and carbon dioxide (CO₂) emissions, depending on engine type, test cycle, and biodiesel feedstock. Therefore, the purpose of this …

Go to article

On Primitivity And Dimension Of Finite Semifields And Their Planes, Linlin Chen Jan 2012

On Primitivity And Dimension Of Finite Semifields And Their Planes, Linlin Chen

Mathematics Dissertations

The study of semifields was originated by L.E. Dickson in 1905 and was greatly developed in the 1960s by Albert, Knuth, Walker, Kleinfeld among others. Two problems of interest in this area are the primitivity of semifields and the dimension of semifields.For the first problem, we provide an equivalent condition for the right (or left) primitivity of finite semifields and with this result, we find that the classical Knuth binary semifields of order 2^{15}, 2^{17} and 2^{19} are all right and left primitive; the Albert semifields of order 2^i, where i=7, 9, 11, 13 are all primitive. Also we prove …

Go to article

Resolutions And Tor Algebra Structures For Trivariate Monomial Ideals, Jared Lafayette Painter Jan 2012

Resolutions And Tor Algebra Structures For Trivariate Monomial Ideals, Jared Lafayette Painter

Mathematics Dissertations

In this manuscript we explore properties of minimal free resolutions and their relationship to the Tor-algebra structure for trivariate monomial ideals. We begin with an in-depth analysis of minimal free resolutions of S = R / I, where R = k[x; y; z] is a polynomial ring over a field k, and I is a monomial ideal that is primary to the homogeneous maximal ideal m of R. We will de ne a special form of the minimal free resolution of S, and then determine when we get nonzero elements from I as entries in the matrices of the resolution. …

Go to article

High Order Dns For Late Flow Transition, Ping Lu Jan 2012

High Order Dns For Late Flow Transition, Ping Lu

Mathematics Dissertations

In this report, a new high order scheme for boundary points is introduced when calculating the derivative of smooth functions by Compact Scheme. The primitive function reconstruction method of ENO schemes is applied to obtain the conservative form of the Compact Scheme. Meanwhile, modified compact scheme is developed by using an effective shock detector to block upwinding compact scheme to cross the shock, a control function, and an adaptive scheme which uses some WENO flux near the shock. The new scheme makes the original upwinding compact scheme able to capture the shock sharper than WENO and, more important, keep high …

Go to article

New Results In Finite Geometries Pertaining To Albert-Like Semifields, Angela Michelle Brown Jan 2012

New Results In Finite Geometries Pertaining To Albert-Like Semifields, Angela Michelle Brown

Mathematics Dissertations

One of the most widely studied class of semifields are the generalized twisted fields defined by Albert in the 50s and 60s. The collineation groups of generalized twisted field planes have been completely described. In a series of papers Cordero and Figueroa studied semifields with an autotopism that acts transitively on one side of the autotopism triangle, equivalently the plane admits an autotopism which induces a permutation on a side of the autotopism triangle of order a p-primitive divisor of pr - 1. They showed that with some minor exceptions the plane is a generalized twisted field plane. These planes …

Go to article

From Discrete To Continuous Models Of Cell Movement: An Application To Medical Implants, Alicia Prieto Langarica Jan 2012

From Discrete To Continuous Models Of Cell Movement: An Application To Medical Implants, Alicia Prieto Langarica

Mathematics Dissertations

Mathematical modeling of cell movement is needed to aid in the deeper understanding of vital processes such as embryogenesis, angiogenesis, tumor metastasis, and immune reactions to foreign bodies. In this work, cell movement and growth in response to external stimulus and the interactions between cells and the stimulus are considered. In order to model the random nature of the movement, a discrete model is created to simulate cells moving in the presence of a growing and moving stimulus distribution. The model also includes the depletion of the stimulus under the presence of cells. The discrete model is then upscaled, based …

Go to article

A Study On The Two Component Periodic Shallow Water Systems, Caixia Chen Jan 2012

A Study On The Two Component Periodic Shallow Water Systems, Caixia Chen

Mathematics Dissertations

In this dissertation we study the generalized periodic two-component Camassa-Holm system and the generalized periodic two-component Dullin-Gottwald-Holm system, which can be derived from the Euler equation with nonzero constant vorticity in shallow water waves moving over a linear shear flow. The precise blow-up scenarios of strong solutions and several results of blow-up solutions with certain initial profiles are described in detail. The exact blow-up rates are also determined. Finally, the sufficient conditions for global solutions are established.

Go to article

Gis Data: Prince William County, Virginia Tidal Marsh Inventory, Marcia Berman, Harry Berquist, Sharon A. Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky Jan 2012

Gis Data: Prince William County, Virginia Tidal Marsh Inventory, Marcia Berman, Harry Berquist, Sharon A. Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky

Data

The 2012 Tidal Marsh Inventory update for Prince William County, Virginia was generated using on-screen digitizing techniques in the most recent version of ArcGIS® - ArcMap while viewing conditions observed in the most recent imagery from the Virginia Base Mapping Program (VBMP). Dominant plant community types were primarily determined during field surveys from shallow-draft boats moving along the shoreline. Land-based surveys were performed in some locations. One shapefile is developed that portrays tidal marsh areas represented as polygons. A metadata file accompanies the shapefile to define attribute accuracy, data development, and any use restrictions that pertain to the data.

Go to article

Gis Data: Mathews County, Virginia Tidal Marsh Inventory, Marcia Berman, Harry Berquist, Sharon Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt, David Weiss Jan 2012

Gis Data: Mathews County, Virginia Tidal Marsh Inventory, Marcia Berman, Harry Berquist, Sharon Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt, David Weiss

Data

The 2012 Tidal Marsh Inventory update for Mathews County, Virginia was generated using on-screen digitizing techniques in the most recent version of ArcGIS® - ArcMap while viewing conditions observed in the most recent imagery from the Virginia Base Mapping Program (VBMP). Dominant plant community types were primarily determined during field surveys from shallow-draft boats moving along the shoreline. Land-based surveys were performed in some locations. One shapefile is developed that portrays tidal marsh areas represented as polygons. A metadata file accompanies the shapefile to define attribute accuracy, data development, and any use restrictions that pertain to the data.

Go to article

Energy-Efficient Protocols And Systems For Wireless Sensor Networks And Smart Environments, Giacomo Ghidini Jan 2012

Energy-Efficient Protocols And Systems For Wireless Sensor Networks And Smart Environments, Giacomo Ghidini

Computer Science and Engineering Dissertations

In a wireless sensor network, small computing devices, called sensors, sense the surrounding environment and relay the sensed data to a base station over a multi-hop wireless network, eventually processing them en-route. Wireless sensor networks and other devices, such as smartphones, smart meters, and smart appliances, cooperate in smart environments to obtain information about the environment, and then use this information to improve the experience of the users. Since most of these systems rely on battery power, there is a need for energy-efficient solutions for their operation. The objective of this dissertation is to design algorithms and protocols to improve …

Go to article

Effective And Secure Use Of Human Relation Networks, Na Li Jan 2012

Effective And Secure Use Of Human Relation Networks, Na Li

Computer Science and Engineering Dissertations

With the advent of Web 2.0 and advanced techniques of wireless devices (e.g., smart phones or iPhones), Online Social Networks (OSNs) and Mobile Social Networks (MSNs) are becoming integral part of our lives as two main digital social communities. Data collected from people's communication on OSNs and MSNs contains valuable information which makes human relationships more visible as compared to their existence in our physical world. For instance, the friend list on a user's profile page on Facebook clearly tells us the user's friendships with other users. Moreover, the short-range wireless communication techniques (e.g., Bluetooth) also enable us to “sense” …

Go to article

An Updated Gps Velocity Field For Puerto Rico And The Virgin Islands: Constraints On Tectonic Setting And Internal-Deformation, Desmond Kelvin Ihemedu Dec 2011

An Updated Gps Velocity Field For Puerto Rico And The Virgin Islands: Constraints On Tectonic Setting And Internal-Deformation, Desmond Kelvin Ihemedu

Earth & Environmental Sciences Theses

Puerto Rico and the northern Virgin Islands define the eastern end of the Greater Antilles, while the Puerto Rico trench and the Muertos Trough define the northern and the southern limits of the North American - Caribbean plate boundary zone. Three microplates have been defined: (1) Gonave, to the west; (2) Hispaniola, at the center; and (3) Puerto Rico and the northern Virgin Islands (PRVI) at the eastern end. Global Positioning System (GPS) geodesy was previously conducted in this region from 1994 to 2003. It was concluded that the locus of the highest permissible on-surface deformation in Puerto Rico and …

Go to article

Results Of The Ioos Testbed For Comparison Of Hydrodynamic Models Of The Chesapeake Bay, Carl T. Friedrichs, A. J. Bever, M.A.M. Friedrichs, M.E. Scully Nov 2011

Results Of The Ioos Testbed For Comparison Of Hydrodynamic Models Of The Chesapeake Bay, Carl T. Friedrichs, A. J. Bever, M.A.M. Friedrichs, M.E. Scully

Presentations

No abstract provided.

Go to article

Is There Any Air Down There? Using Multiple 3d Numerical Models To Investigate Hypoxic Volumes Within The Chesapeake Bay, A. J. Bever, M.A.M. Friedrichs, Carl T. Friedrichs Nov 2011

Is There Any Air Down There? Using Multiple 3d Numerical Models To Investigate Hypoxic Volumes Within The Chesapeake Bay, A. J. Bever, M.A.M. Friedrichs, Carl T. Friedrichs

Presentations

No abstract provided.

Go to article

Results Of The Ioos Testbed For Comparison Of Hydrodynamic Models Of The Chesapeake Bay, Carl T. Friedrichs, A. J. Bever, M.A.M. Friedrichs, M. E. Scully Nov 2011

Results Of The Ioos Testbed For Comparison Of Hydrodynamic Models Of The Chesapeake Bay, Carl T. Friedrichs, A. J. Bever, M.A.M. Friedrichs, M. E. Scully

Presentations

No abstract provided.

Go to article

Is There Any Air Down There? Using Multiple 3d Numerical Models To Investigate Hypoxic Volumes Within The Chesapeake Bay, A. J. Bever, M. A.M. Friedrichs, Carl T. Friedrichs Nov 2011

Is There Any Air Down There? Using Multiple 3d Numerical Models To Investigate Hypoxic Volumes Within The Chesapeake Bay, A. J. Bever, M. A.M. Friedrichs, Carl T. Friedrichs

Presentations

No abstract provided.

Go to article

Results Of The Us Ioos Testbed For Comparison Of Hydrodynamic And Hypoxia Models Of The Chesapeake Bay, Carl T. Friedrichs, A. J. Bever, M.A.M. Friedrichs, M. E. Scully Oct 2011

Results Of The Us Ioos Testbed For Comparison Of Hydrodynamic And Hypoxia Models Of The Chesapeake Bay, Carl T. Friedrichs, A. J. Bever, M.A.M. Friedrichs, M. E. Scully

Presentations

No abstract provided.

Go to article

Estuarine Hypoxia Component Of Testbed 2, Marjorie A.M. Friedrichs, Carl T. Friedrichs, W. Long, R. Hood Oct 2011

Estuarine Hypoxia Component Of Testbed 2, Marjorie A.M. Friedrichs, Carl T. Friedrichs, W. Long, R. Hood

Presentations

No abstract provided.

Go to article

Development Of A Passive Sampler For Gaseous Mercury, Mae S. Gustin, Seth N. Lyman, P. Kilner, E. Prestbo Oct 2011

Development Of A Passive Sampler For Gaseous Mercury, Mae S. Gustin, Seth N. Lyman, P. Kilner, E. Prestbo

USU Uintah Basin Faculty Publications

Here we describe work toward development of the components of a cost effective passive sampling system for gaseous Hg that could be broadly deployed by nontechnical staff. The passive sampling system included an external shield to reduce turbulence and exposure to precipitation and dust, a diffusive housing that directly protects the collection surface during deployment and handling, and a collection surface. A protocol for cleaning and deploying the sampler and an analytical method were developed. Our final design consisted of a polycarbonate external shield enclosing a custom diffusive housing made from expanded PTFE tubing. Two collection surfaces were investigated, gold …

Go to article

Damping Of Turbulence By Suspended Sediment In The Bottom Boundary Layer, Carl T. Friedrichs Sep 2011

Damping Of Turbulence By Suspended Sediment In The Bottom Boundary Layer, Carl T. Friedrichs

Presentations

No abstract provided.

Go to article

A Data-Driven Approach For Processing Heterogeneous Categorical Sensor Signals, Randy Paffenroth, Christopher Calderon, Austin Jones, Scott Lundberg Sep 2011

A Data-Driven Approach For Processing Heterogeneous Categorical Sensor Signals, Randy Paffenroth, Christopher Calderon, Austin Jones, Scott Lundberg

Randy C. Paffenroth

False alarms generated by sensors pose a substantial problem to a variety of fusion applications. We focus on situations where the frequency of a genuine alarm is "rare" but the false alarm rate is high. The goal is to mitigate the false alarms while retaining power to detect true events. We propose to utilize data streams contaminated by false alarms (generated in the field) to compute statistics on a single sensor's misclassification rate. The nominal misclassification rate of a deployed sensor is often suspect because it is unlikely that these rates were tuned to the specific environmental conditions in which …

Go to article

Operation Comics: Making Math Fun, Bruce Kessler Sep 2011

Operation Comics: Making Math Fun, Bruce Kessler

Mathematics Faculty Publications

This talk gives a background on the Operation Comics series, which integrates mathematics into a comic book storyline, as an example of how creativity is not exclusive to the traditional arts, like music and dance, but is a vital part of math, science, and engineering.

Go to article

First Prev Next Last