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

Digital Commons Network™

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

Clemson University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 3541 - 3570 of 5674

Full-Text Articles in Entire DC Network

Quality Representation In Multiobjective Programming, Stacey Faulkenberg Aug 2009

Quality Representation In Multiobjective Programming, Stacey Faulkenberg

All Dissertations

In recent years, emphasis has been placed on generating quality representations of the nondominated set of multiobjective programming problems. This manuscript presents two methods for generating discrete representations with equidistant points for multiobjective programs with solution sets determined by convex cones. The Bilevel Controlled Spacing (BCS) method has a bilevel structure with the lower-level generating the nondominated points and the upper-level controlling the spacing. The Constraint Controlled Spacing (CCS) method is based on the epsilon-constraint method with an additional constraint to control the spacing of generated points. Both methods (under certain assumptions) are proven to produce (weakly) nondominated points. Along …

Go to article

Development Of Improved Torsional Potentials In Classical Force Field Models Of Poly (Lactic Acid), James Mcaliley Aug 2009

Development Of Improved Torsional Potentials In Classical Force Field Models Of Poly (Lactic Acid), James Mcaliley

All Dissertations

In this work, existing force field descriptions of poly (lactic acid), or PLA, were improved by modifying the torsional potential energy terms to more accurately model the bond rotational behavior of PLA. Extensive calculations were carried out using density functional theory (DFT), for small PLA molecules in vacuo, and also using DFT with a continuum model to approximate the electronic structure of PLA in its condensed phase. From these results, improved force field parameters were developed using a combination of the OPLS and CHARMM force fields. The new force field, PLAFF2, is an update to the previously developed PLAFF model …

Go to article

Effect Of Cosb3 Nanoparticles On The Thermoelectric Properties Of Filled And Unfilled Cosb3 Skutterudites, Paola Alboni Aug 2009

Effect Of Cosb3 Nanoparticles On The Thermoelectric Properties Of Filled And Unfilled Cosb3 Skutterudites, Paola Alboni

All Dissertations

This study explores the possibility of somewhat decoupling the electrical and thermal conduction, thereby being able to limit the thermal conduction while minimizing the effect on the electrical conduction. The approach is using a nanoparticle layer with a slight compositional mismatch as compared to the bulk skutterudite. A hydrothermal nanoparticle-plating technique has been employed to grow a layer of CoSb3 nanoparticles on the surface of skutterudite bulk matrix grains. Skutterudites of various forms were fabricated and studied in order to assess the effect of this nano-plated layer as a viable method in the improvement of thermoelectric properties of CoSb …

Go to article

Population Ecology Of The Floodplain Herb Macbridea Caroliniana (Lamiaceae) With Investigations On The Species' Habitat, Breeding System And Genetic Diversity, Katherine Weeks Aug 2009

Population Ecology Of The Floodplain Herb Macbridea Caroliniana (Lamiaceae) With Investigations On The Species' Habitat, Breeding System And Genetic Diversity, Katherine Weeks

All Dissertations

The perennial herbaceous mint Macbridea caroliniana is known from 36 locations in discrete watersheds of the Carolinas and Georgia. It is one of relatively few conspicuously flowering herbs that occupy bottomland hardwood forests. The general project goal was to gain knowledge that is applicable to the species' conservation both at the Congaree National Park (CNP) where the largest known population of this species occurs and range-wide. Specific objectives were to (1) quantify the population size and describe the distribution of M. caroliniana within CNP, and determine the extent of co-occurrence with wild hogs and the non-native Murdannia keisak; (2) identify …

Go to article

Development And Integration Of Geometric And Optimization Algorithms For Packing And Layout Design, Santosh Tiwari Aug 2009

Development And Integration Of Geometric And Optimization Algorithms For Packing And Layout Design, Santosh Tiwari

All Dissertations

The research work presented in this dissertation focuses on the development and application of optimization and geometric algorithms to packing and layout optimization problems. As part of this research work, a compact packing algorithm, a physically-based shape morphing algorithm, and a general purpose constrained multi-objective optimization algorithm are proposed. The compact packing algorithm is designed to pack three-dimensional free-form objects with full rotational freedom inside an arbitrary enclosure such that the packing efficiency is maximized. The proposed compact packing algorithm can handle objects with holes or cavities and its performance does not degrade significantly with the increase in the complexity …

Go to article

Synthesis And Characterization Of Magnetic Solids Containing Periodic Arrays Of Transition Metal Oxide Nanostructures, Wendy Queen Aug 2009

Synthesis And Characterization Of Magnetic Solids Containing Periodic Arrays Of Transition Metal Oxide Nanostructures, Wendy Queen

All Dissertations

The ultimate goal of the research presented in this dissertation was to explore new systems containing low–dimensional magnetic nanostructures in hopes of finding new extended solids exhibiting novel magnetic properties due to the confined magnetic lattices. The scope of this research is threefold: 1) to explore new solids containing low–dimensional magnetic nanostructures in the A–M–X–O system, where A is an alkali or alkalinendash;earth metal cation, M is a first–row transition metal cation, and X is P, As, or V, 2) to characterize these new materials and, through chemical substitution, fine tune (and optimize) magnetic and electronic properties of solids that …

Go to article

Fast Rendering Of Forest Ecosystems With Dynamic Global Illumination, Jay Steele Aug 2009

Fast Rendering Of Forest Ecosystems With Dynamic Global Illumination, Jay Steele

All Dissertations

Real-time rendering of large-scale, forest ecosystems remains
a challenging problem, in that important global illumination effects,
such as leaf transparency and inter-object light scattering, are
difficult to capture, given tight timing constraints and scenes
that typically contain hundreds of millions of primitives.
We propose a new lighting model, adapted from
a model previously used to light convective clouds and other
participating media,
together with GPU ray tracing, in order to achieve these global illumination
effects while maintaining near real-time performance. The lighting
model is based on a lattice-Boltzmann method in which
reflectance, transmittance, and absorption parameters are
taken from measurements …

Go to article

Asymptotics Of Families Of Polynomials And Sums Of Hurwitz Class Numbers, Timothy Flowers Aug 2009

Asymptotics Of Families Of Polynomials And Sums Of Hurwitz Class Numbers, Timothy Flowers

All Dissertations

In a note in the American Mathematical Monthly in 1960, Strodt mentions a way to prove both the Euler-Maclaurin summation formula and the Boole summation formula using operators. In a 2009 article in the Monthly, Borwein, Calkin, and Manna expand on this idea. Therein, they define Strodt operators and Strodt polynomials and show that the classical Bernoulli polynomials and Euler polynomials are examples of Strodt polynomials.
It is well known that both Bernoulli polynomials and Euler polynomials on a fixed interval are asymptotically sinusoidal. Borwein, Calkin, and Manna show that a similar result holds for the uniform Strodt polynomials. We …

Go to article

The Dynamics Of Energy And Charge Transfer In Low And Hyperthermal Energy Ion-Solid Interactions, Matthew Ray Aug 2009

The Dynamics Of Energy And Charge Transfer In Low And Hyperthermal Energy Ion-Solid Interactions, Matthew Ray

All Dissertations

The energy and charge transfer dynamics for low and hyperthermal energy (10 eV to 2 keV) alkali and noble gas ions impacting noble metals as a function of incident energy, species and scattering geometry has been studied. The experiments were performed in an ultra-high vacuum scattering chamber attached to a low and hyperthermal energy beamline.
The energy transfer was measured for K+ scattered from a Ag(001) surface along the [110] crystalline direction at a fixed laboratory angle of 90°. It was found that as the incident energy is reduced from 100 to 10 eV, the normalized scattered energy increased. Previous …

Go to article

Pattern Recognition For Command And Control Data Systems, Jason Schwier Aug 2009

Pattern Recognition For Command And Control Data Systems, Jason Schwier

All Dissertations

To analyze real-world events, researchers collect observation data from an underlying process and construct models to represent the observed situation. In this work, we consider issues that affect the construction and usage of a specific type of model. Markov models are commonly used because their combination of discrete states and stochastic transitions is suited to applications with both deterministic and stochastic components. Hidden Markov Models (HMMs) are a class of Markov model commonly used in pattern recognition. We first demonstrate how to construct HMMs using only the observation data, and no a priori information, by extending a previously developed approach …

Go to article

Discrete Dynamics Over Finite Fields, Jang-Woo Park Aug 2009

Discrete Dynamics Over Finite Fields, Jang-Woo Park

All Dissertations

A dynamical system consists of a set V and a map f : V → V . The primary goal is to characterize points in V according to their limiting behaviors under iteration of the map f . Especially understanding dynamics of nonlinear maps is an important but difficult problem, and there are not many methods available. This work concentrates on dynamics of certain nonlinear maps over finite fields. First we study monomial dynamics over finite fields. We show that determining the number of fixed points of a boolean monomial dynamics is #P–complete problem and consider various cases in which …

Go to article

Synthesis Of Polymers Featuring Novel Diphosphines, Eleanor Tennyson Aug 2009

Synthesis Of Polymers Featuring Novel Diphosphines, Eleanor Tennyson

All Theses

This report details the synthesis of functionalized platinum-based metallopolymers featuring m-terphenyl-scaffolded and light-harvesting phosphine ligands. Substituents placed on both the phosphine and pendant alkynyl units can enhance the optical activity of the metallopolymers depending on their inherent properties. The presence of the platinum metal atom can be exploited to increase conductivity of the molecule and promises to be a unique and valuable modification for polymers to be used in light emitting diodes and photovoltaics. Light-harvesting phosphines prepared in the course of the metallopolymer development have also been used to prepare luminescent polyelectrolytes that prove valuable for well-defined composite film formation …

Go to article

Modeling Nitrogen Loss From Regional Switchgrass Agriculture, Saumya Sarkar Aug 2009

Modeling Nitrogen Loss From Regional Switchgrass Agriculture, Saumya Sarkar

All Theses

A water quality modeling study was conducted to determine and compare nitrogen loss from agricultural systems growing switchgrass and cotton in the southeastern USA. The water quality impacts were modeled at the plot scale and at the watershed scale. The Soil and Water Assessment Tool (SWAT) was used to replicate field conditions observed at switchgrass research plots at Pee Dee Research and Educational Center at Florence, South Carolina. The plot scale modeling suggested that in the early years of growth there is significant nitrogen loss from switchgrass to streamflow and groundwater but they are significantly less as the switchgrass matures. …

Go to article

Predictive Energy Management In Smart Vehicles: Exploiting Traffic And Traffic Signal Preview For Fuel Saving, Behrang Asadi Aug 2009

Predictive Energy Management In Smart Vehicles: Exploiting Traffic And Traffic Signal Preview For Fuel Saving, Behrang Asadi

All Theses

This master thesis proposes methods for improving fuel economy and emissions of vehicles via use of future information of state of traffic lights, traffic flow, and deterministic traffic flow models.
The first part of this thesis proposes use of upcoming traffic signal information
within the vehicle's adaptive cruise control system to reduce idle time at stop lights and lower fuel use. To achieve this goal an optimization-based control algorithm is formulated for each equipped vehicle that uses short range radar and traffic signal information predictively to schedule an optimum velocity trajectory for the vehicle. The objectives are timely arrival at …

Go to article

Local Adaptive Smoothing In Kernel Regression Estimation, Qi Zheng Aug 2009

Local Adaptive Smoothing In Kernel Regression Estimation, Qi Zheng

All Theses

We consider nonparametric estimation of a smooth regression function of one variable. In practice it is quite popular to use the data to select one global smoothing parameter. Such global selection procedures cannot sufficiently account for local sparseness of the covariate nor can they adapt to local curvature of the regression function. We propose a new method to select local smoothing parameters which takes into account sparseness and adapts to local curvature of the regression function. A Bayesian method allows the smoothing parameter to adapt to the local sparseness of the covariate and provides the basis for a local cross …

Go to article

Structural Role Of Pseudouridines In The Peptidyl Transferase Center Of Human 28s Ribosomal Rna, Chris Mart Aug 2009

Structural Role Of Pseudouridines In The Peptidyl Transferase Center Of Human 28s Ribosomal Rna, Chris Mart

All Theses

The human ribosome is an RNA-protein complex responsible for protein synthesis in the cell. Crystal structures of bacterial ribosomes solved to date depict no protein sidechains within the catalytic core, or peptidyl transferase center (PTC). This region of the human ribosome comprises approximately 230 highly conserved nucleotides. Notably, several of the uridine bases clustered within the human PTC are post-transcriptionally modified to pseudouridines, as compared with bacterial analogues. Pseudouridines are base-rotated uridines, linked to their sugar moieties through C5-C1' linkages, affording additional hydrogen-bond donor groups at the N1 position of their rings. A connection was recently made between the absence …

Go to article

Development Of A Rigid Ring Tire Model And Comparison Among Various Tire Models For Ride Comfort Simulations, Norm Frey Aug 2009

Development Of A Rigid Ring Tire Model And Comparison Among Various Tire Models For Ride Comfort Simulations, Norm Frey

All Theses

One vehicle subassembly that is of great importance to automobile manufacturers for tuning final vehicle performance is the pneumatic tire. Pneumatic tires present themselves as unique tuning tools as they 1) are the sole link between the roadway surface and the integrated vehicle suspension, chassis and steering systems, and 2) provide a wide range of tunability over many vehicle performances, including handling (steering feel as well as chassis dynamics), traction (braking, driving, and cornering), and ride comfort (roadway isolation). Therefore the vehicle manufacturing industry continues to research and refine various aspects of tire modeling to improve up-front integrated tire/vehicle CAE/CAD …

Go to article

On The Modeling Of Energy Harvesters And Analysis Of Their Response Under Time-Varying Frequency Excitations, Thiago Seuaciuc-Osorio Aug 2009

On The Modeling Of Energy Harvesters And Analysis Of Their Response Under Time-Varying Frequency Excitations, Thiago Seuaciuc-Osorio

All Theses

Energy harvesting is a process by which otherwise wasted ambient energy can be captured and transformed into a useful form. Historical examples of this concept include windmills, sailing ships, and waterwheels. Modern technologies and current energy needs have brought this same concept to a smaller scale wherein small wireless devices with minute energy consumption can be operated autonomously. Today, many critical electronic devices, such as health-monitoring sensors, pace makers, spinal stimulators, electric pain relievers, etc. require minimal amounts of power to function, which permits utilizing energy from their environment to power them. By exploiting the ability of active materials and …

Go to article

Synthesis Of Optimal Usage Of Available Aggregates In Highway Construction And Maintenance, Benjamin Skidmore Aug 2009

Synthesis Of Optimal Usage Of Available Aggregates In Highway Construction And Maintenance, Benjamin Skidmore

All Theses

The optimization of the available aggregates for highway construction and maintenance is vital both from an economic and environmental perspective. By not optimizing the aggregate supply project costs escalate as a simple response to supply and demand, and just as important the fact that aggregate is a natural resource and a limited one, it is crucial that is used as efficiently as possible. This paper examines specifically the use of aggregates by the South Carolina Department of Transportation, but can easily be adapted to any state. Through DOT and quarry surveys and an examination of aggregate gradation specifications it was …

Go to article

Sparse Representations In Power Systems Signals, Jack Cooper Aug 2009

Sparse Representations In Power Systems Signals, Jack Cooper

All Theses

This thesis seeks to detect transient disturbances in power system signals in a sparse framework. To this end, an overcomplete wavelet packet dictionary and damped sinusoid dictionary are considered, and for each dictionary Matching Pursuit is compared with Basis Pursuit. Previous work in developing waveform dictionary theory and sparse representation is reviewed, and simulations are run on a test signal in both noisy and noiseless environments. The solutions are viewed as time-frequency plane tilings to compare the accuracy and sparsity of these algorithms in properly resolving optimal representations of the disturbances. The advantages and disadvantages of each combination of dictionary …

Go to article

A Study For Scalable Directory In Parallel File Systems, Yang Wu Aug 2009

A Study For Scalable Directory In Parallel File Systems, Yang Wu

All Theses

One of the challenges that the design of parallel file system for
HPC(High Performance Computing) has to face today is maintaining the
scalability to handle the I/O generated by parallel applications that
involve accessing directories containing a large number of entries and
performing hundreds of thousands of operations per second. Currently,
highly concurrent access to large directories is poorly supported in
parallel file systems. As a result, it is important to build a
scalable directory service for parallel file systems to support
efficient concurrent access to larger directories.
In this thesis we demonstrate a scalable directory service designed
for parallel …

Go to article

A Spectroscopic Analysis Of V505 Persei And The Origin Of The Lithium Dip, Patrick Baugh Aug 2009

A Spectroscopic Analysis Of V505 Persei And The Origin Of The Lithium Dip, Patrick Baugh

All Theses

We study the observed Li Dip in stellar clusters and field stars, testing Rotationally Induced Mixing (RIM) by measuring Li abundances in a middle-aged (1.1±0.15 Gyr), metal poor ([Fe/H]=-0.15±0.03), short period binary, V505 Per, finding Li abundances of Log N(Li)=2.67±0.1 and 2.42±0.2 from the primary and secondary components, respectively. These abundances are significantly higher than observed abundances from single stars of similar metallicity and ZAMS Teff; as shown by comparison with NGC 752, and suggest that RIM may be a primary cause of the Li Dip.

Go to article

Accuracy And Multi-Core Performance Of Machine Learning Algorithms For Handwritten Character Recognition, Sumod Mohan Aug 2009

Accuracy And Multi-Core Performance Of Machine Learning Algorithms For Handwritten Character Recognition, Sumod Mohan

All Theses

There have been considerable developments in the quest for intelligent machines since the beginning of the cybernetics revolution and the advent of computers. In the last two decades with the onset of the internet the developments have been extensive. This quest for building intelligent machines have led into research on the working of human brain, which has in turn led to the development of pattern recognition models which take inspiration in their structure and performance from biological neural networks. Research in creating intelligent systems poses two main problems. The first one is to develop algorithms which can generalize and predict …

Go to article

The Effect Of Bio-Based Materials On Quality And Shelf Life Of Celery, Chike Ifezue Aug 2009

The Effect Of Bio-Based Materials On Quality And Shelf Life Of Celery, Chike Ifezue

All Theses

Bio-based materials have garnered increasing interest as food packaging
materials because they are derived from renewable resources such
as corn starch, cellulose and sugar beet. These materials do have the disadvantage
of having
poor mechanical performance compared to non-bio based materials and their
effect on quality and shelf life of some produce is unknown.
This research studied the effect of three bio-based materials on quality
and self life of celery. Materials consist of biopolymer films and LDPE
film. The variable materials were: Polylactic Acid (PLA), a versatile
biodegradable aliphatic polyester derived from 100% renewable resources,
Ecoflex, a biodegradable aliphatic-aromatic copolyester, …

Go to article

Survey Of Concurrent Engineering Environments And The Application Of Best Practices Towards The Development Of A Multiple Industry, Multiple Domain Environment, Jonathan Osborn Aug 2009

Survey Of Concurrent Engineering Environments And The Application Of Best Practices Towards The Development Of A Multiple Industry, Multiple Domain Environment, Jonathan Osborn

All Theses

This thesis investigates the best practices of fifteen existing Concurrent Engineering Environments (CEE). A CEE is defined as any environment, from physical to virtual, designed to facilitate concurrent engineering with multiple domain experts real time. All existing environments surveyed have been focused on the aerospace industry showing significant reductions in design time and cost. I have identified hardware, software, and peopleware as three major classifications as well as sixteen subcategories with which to compare the different CEEs. The success in reducing time and cost of designs seen in the aerospace industry with the introduction of CEEs can and should be …

Go to article

Hydraulic Modeling To Inform Stream Maintenance Practices In South Carolina, Kelly Owens Aug 2009

Hydraulic Modeling To Inform Stream Maintenance Practices In South Carolina, Kelly Owens

All Theses

The Crabtree Canal located in Horry County, SC is the main conveyor of stormwater in a watershed that has undergone considerable urbanization in the last few decades. Evidence of bank instability and inchannel erosion is widely seen in the Crabtree Canal system. Principal sediment inputs are landscape sources and in-channel sources. A study was initiated to provide a working management tool to determine hydrodynamic conditions on the watershed driven by a hypothetical storm event and alternative channel configurations. The management tool comprised of a one-dimensional HEC-RAS model of the Crabtree Canal and was developed to aid the Horry County stormwater …

Go to article

Operation Assessment Of Reservoirs In The Savannah River Basin, Travis Yates Aug 2009

Operation Assessment Of Reservoirs In The Savannah River Basin, Travis Yates

All Theses

Hydropower is generated from three reservoirs in the United States Army Corps of Engineer's Savannah District. These reservoirs include J. Strom Thurmond, Richard B. Russell, and Hartwell. Currently, a contract in place specifies that certain amount of energy must be provided to the region. The contract for the hydropower was based upon the critical hydrologic year of 1981. Historically, this was the most severe drought on record and assumed to provide the lowest net inflows for the three reservoirs, thus providing an attainable or reliable energy amount for the system, which suggests a dependable energy yield.
Reevaluating the contract amount …

Go to article

Non-Rigid Multi-Modal Object Tracking Using Gaussian Mixture Models, Prakash Chockalingam Aug 2009

Non-Rigid Multi-Modal Object Tracking Using Gaussian Mixture Models, Prakash Chockalingam

All Theses

This work presents an approach to visual tracking based on dividing a target into multiple regions, or fragments. The target is represented by a Gaussian mixture model in a joint feature-spatial space, with each ellipsoid corresponding to a different fragment. The fragment set and its cardinality are automatically adapted to the image data using an efficient region-growing procedure and updated according to a weighted average of the past and present image statistics. The fragment modeling is used to generate a strength map indicating the probability of each pixel belonging to the foreground. The strength map provides vital information about new …

Go to article

Accurate Tracking Of Objects Using Level Sets, Nalin Senthamil Aug 2009

Accurate Tracking Of Objects Using Level Sets, Nalin Senthamil

All Theses

Our current work presents an approach to tackle the challenging task of tracking objects in Internet videos taken from large web repositories such as YouTube. Such videos more often than not, are captured by users using their personal hand-held cameras and cellphones and hence suffer from problems such as poor quality, camera jitter and unconstrained lighting and environmental settings. Also, it has been observed that events being recorded by such videos usually contain objects moving in an unconstrained fashion. Hence, tracking objects in Internet videos is a very challenging task in the field of computer vision since there is no …

Go to article

Phenomenological Investigation Of The Effectiveness Of A Cooperative Problem-Based Laboratory And A Metacognitive Problem-Solving Exercise, Todd Gatlin Aug 2009

Phenomenological Investigation Of The Effectiveness Of A Cooperative Problem-Based Laboratory And A Metacognitive Problem-Solving Exercise, Todd Gatlin

All Theses

Problem-solving has been described by many as the most important goal of chemistry teaching and learning. Solving real problems requires not only cognitive abilities but also a regulation of those abilities-metacognition. In fact, metacognition is recognized as having considerable impact on problem-solving success and learning. Recent research focused on the development of interventions designed to enhance the use of metacognition. The main objective of this study was to determine 'how' and 'why' two interventions were effective in increasing students' metacognitive use, and problem-solving abilities. Therefore, this study represents the qualitative portion of a sequential explanatory mixed-methods study; Qualitative evidence was …

Go to article

First Prev Next Last