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Multileaf Collimator Positional Reproducibility Evaluated With A Two-Dimensional Diode Array, Kara King Ferachi Jan 2003

Multileaf Collimator Positional Reproducibility Evaluated With A Two-Dimensional Diode Array, Kara King Ferachi

LSU Master's Theses

When delivering the total dose via a sequence of small fields shaped by a multileaf collimator, it is important to consider leaf positional reproducibility. A small error in the leaf position can result in large dose errors to the entire field. This is true for both dynamic multileaf collimation and step and shoot delivery. The goal of this research project is to design a method of quality assurance that is easily reproducible, sensitive to small changes in leaf position, and requires minimal time on the part of the medical physicist to carry out. This paper describes a system of measurements …


Economic Analysis Of The Best Management Practices (Bmps) In Louisiana Sugarcane Production, Ying Zhong Jan 2003

Economic Analysis Of The Best Management Practices (Bmps) In Louisiana Sugarcane Production, Ying Zhong

LSU Master's Theses

Agriculture has been identified as one of the major sources of nonpoint water pollution due to discharges running off farmland. This study assessed the current adoption of Best Management Practices (BMPs) in the Louisiana sugarcane industry and provided policy recommendations based on the empirical results. Fifteen BMPs recommended by Louisiana State University Agricultural Center were examined in three categories: Soil Erosion and Sediment Control, Nutrient Management, and Pesticide Management. Based on neoclassical economic principles of individual’s utility maximization, this study evaluated seven multivariate probit models using primary data collected from a mail survey of Louisiana’s sugarcane producers. The results indicated …


An Investigation Of A Salt-Dome Environment At South Timbalier 54, Gulf Of Mexico, Robert E. Little, Jr Jan 2003

An Investigation Of A Salt-Dome Environment At South Timbalier 54, Gulf Of Mexico, Robert E. Little, Jr

LSU Master's Theses

Salt domes have been studied in the Gulf Coast region to look at how, why, and where saline waters are located within these field areas. Fluid flow model and pathway studies can be helpful to the research of saline water migration because it can be correlated to hydrocarbon migration in petroleum exploration. The South Timbalier 54 field occurs over a salt dome that sits at approximately 3,048 meters beneath the seafloor. Two major faults were found originating from the salt dome up into the shallow section of the field. The sands were deposited in fluvial, deltaic, or marine environments. The …


Using Functional Distance Measures When Calibrating Journey-To-Crime Distance Decay Algorithms, Joshua David Kent Jan 2003

Using Functional Distance Measures When Calibrating Journey-To-Crime Distance Decay Algorithms, Joshua David Kent

LSU Master's Theses

Spatial analysis has long been a valuable tool used within the criminal investigative process. This is especially true for serial offence cases where criminologists apply geographic profiling to model offender mobility and crime distribution patterns in order to estimate a criminal’s likely residence. Yet, traditional analytical methodologies have avoided the utilization of functional distance measures when modeling an offender’s journey-to-crime within an anisotropic landscape. By substituting straight-line Euclidean distances with travel path functional distance measures, the predictive utility and technological prerequisites associated with geographically profiling a localized serial offender was assessed using mathematically calibrated distance decay models. Both the travel-path …


Blind Fault Detection Using Spectral Signatures, Pallavi Chethan Jan 2003

Blind Fault Detection Using Spectral Signatures, Pallavi Chethan

LSU Master's Theses

This work studies a blind fault detection method, which only analyses a system's output signal for any change in the characteristics from pre-fault to post-fault to identify the occurrence of faults. In our case the fault considered to develop the procedure is change in time constant of an aircraft's aileron-actuator system and its simplified version - a position servo system. The method is studied as an alternative to conventional fault detection and identification methods. The output signal is passed through a filter bank to enhance the effect of a fault. The Short time Fourier transform is performed on the enhanced …


Effect Of Temperature On Efficiency Of In Situ Bioremediation Technology: A Laboratory Microcosm And Field Study, Javed Iqbal Jan 2003

Effect Of Temperature On Efficiency Of In Situ Bioremediation Technology: A Laboratory Microcosm And Field Study, Javed Iqbal

LSU Master's Theses

Laboratory microcosm experiment and parallel ex situ bioremediation studies were conducted to study the effect of temperature on in situ bioremediation systems installed at Superfund site in southeast Georgia. Laboratory microcosms, inoculated with PAHs/phenols specific microorganisms, at high temperatures (42±2°C; 107±3°F) demonstrated a significant reduction of residual polycyclic aromatic hydrocarbons (PAHs) and selected phenols from 4927±1356ng/g dry weight soil to 1158±530ng/g with a kinetic rate of 76.1±16.8ng/g/day (84% reduction; p≤0.01) in 49days. High temperature non-inoculated microcosms were reduced of residual PAHs and phenols from 1117±436ng/g to 341±116ng/g with a kinetic rate of 15.8±6.5ng/g/day (65% reduction; p≤0.01) in 49days. Low temperature …


A Comparison Of Finfish Assemblages On Subtidal Oyster Shell (Cultched Oyster Lease) And Mud Bottom In Barataria Bay, Louisiana, John Plunket Jan 2003

A Comparison Of Finfish Assemblages On Subtidal Oyster Shell (Cultched Oyster Lease) And Mud Bottom In Barataria Bay, Louisiana, John Plunket

LSU Master's Theses

Recent research suggests that oyster reefs provide unique three-dimensional hard bottom habitat for many fish species. Along the northern shore of the Gulf of Mexico, oyster shell bottoms are predominantly flat, subtidal and cultched, lacking the vertical relief and spatial heterogeneity provided by natural reefs. This study compared finfish assemblages, gut contents, and macroinvertebrate assemblages at subtidal oyster shell (cultched oyster lease) and mud bottoms in Barataria Bay, Louisiana. Three mud and three shell sites were sampled on seven dates from October 2001 to October 2002, using gill nets and substrate trays. Data from the gill nets were used to …


The Use Of The Bang-3 Polymer Gel To Quantify The Three-Dimensional Dose Distribution Of Imrt, Paul Anthony Bruce Jan 2003

The Use Of The Bang-3 Polymer Gel To Quantify The Three-Dimensional Dose Distribution Of Imrt, Paul Anthony Bruce

LSU Master's Theses

The sophistication of radiation therapy delivery techniques at Mary Bird Perkins Cancer Center (MBPCC) creates the need for an advanced dosimetric system that can quantify and verify the dose distributions in three-dimensions. Current dosimetric systems perform this dose analysis in only one or two dimensions. This paper evaluates the application of BANG-3™ polymer gel dosimetry to quantify the 3-D dose distribution of Intensity-Modulated Radiation Therapy (IMRT) using a "step and shoot" approach. The gel was irradiated by 10 MV photons at a dose rate of 400 MU/min. Relaxation rate maps were computed from proton density and T2-weighted magnetic …


Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi Jan 2003

Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi

LSU Master's Theses

In this study, heat transfer coefficient and film effectiveness distributions are investigated for a film cooling hole configuration that has inclined holes discharging into a tangential slot before interactions with the mainstream. The cylindrical holes are inclined 35° along the mainstream direction. The effect of coolant-to-mainstream blowing ratio is examined for M=0.5 and M=1.0. Different slot width to hole ratios and also the effect of hole exit condition (square edge and triangular edge) is considered. The mainstream velocity and free-stream turbulence intensity in the low speed wind tunnel are 9 m/s and 7% respectively and the mainstream Reynolds number based …


Transmission Of Electromagnetic Power Through A Biological Medium, Ripan Das Jan 2003

Transmission Of Electromagnetic Power Through A Biological Medium, Ripan Das

LSU Master's Theses

Primary goal of this work is to study transmission of EM power through a multilayered biological medium. For a particular case study, EM power transmission from an external transmitter to a coupled receiver implanted inside a biological medium simulating a human body is studied to find solutions for factors such as optimum transmission frequency and excitation current. Different aspects of interaction of EM waves with biological bodies and tissues are discussed. Two major factors that may affect transmission of EM power through a biological body are absorption and reflection of EM waves. A simulation in which exact Maxwell's equations are …


Exploring Geometric, Kinematic And Behavioral Scalability Of Microscopic Traffic Simulation Systems, Srikanth Chakravarthy Jan 2003

Exploring Geometric, Kinematic And Behavioral Scalability Of Microscopic Traffic Simulation Systems, Srikanth Chakravarthy

LSU Master's Theses

Even with today's remarkable advancement in computing power, microscopic simulation modeling remains a computationally intensive process that imposes limitations on its potential use for modeling large-scale transportation networks. Research and practice have repeatedly demonstrated that microscopic simulation runs can be excessively time-consuming, depending on the network size, the number of simulated entities (vehicles), and the computational resources available. While microscopic features of a simulated system collectively define the overall system characteristics, it is argued that the microscopic simulation process itself is not necessarily free of redundancy, which if reduced, could substantially improve the computational efficiency of simulation systems without compromising …


A Risk-Averse Strategy For Blackjack Using Fractional Dynamic Programming, Ryan A. Dutsch Jan 2003

A Risk-Averse Strategy For Blackjack Using Fractional Dynamic Programming, Ryan A. Dutsch

LSU Master's Theses

We present how blackjack is related to a discrete-time control problem, rather than a zero-sum game. Using the compiler Visual C++, we write a program for a strategy for blackjack, but instead of maximizing the expected value, we use a risk-averse approach. We briefly describe how this risk-averse strategy is solved by using a special type of dynamic programming called fractional dynamic programming.


Modeling A Mississippi River Diversion Into A Louisiana Wetland, Stephan Alexander Capps Jan 2003

Modeling A Mississippi River Diversion Into A Louisiana Wetland, Stephan Alexander Capps

LSU Master's Theses

Wetland loss has significant impacts. Numerous loss mechanisms have been hypothesized, and a greater number of solutions have been proposed. One proposed solution is to divert river water into a degraded area with the intent of increasing sedimentation, introducing nutrients, and/or decreasing salinity within the wetland. However, wetland hydraulics and hydrology are complex processes and any hydrologic modification may result in unintended consequences. Predicting these consequences can be problematic due to the complexity and difficulty associated with proper modeling of the hydraulics and topography. The primary objective of this study is to evaluate the suitability of established one- and two-dimensional …


Correlation Of Core Characteristics To Outcrop Upper Jackfork Group Turbidites, Degray Lake, Arkansas, Daniel James Golob Jan 2003

Correlation Of Core Characteristics To Outcrop Upper Jackfork Group Turbidites, Degray Lake, Arkansas, Daniel James Golob

LSU Master's Theses

Pennsylvanian age Jackfork Group cores from the DeGray Lake Dam and outcrop from the east wall of the DeGray Lake Spillway, Arkansas, provide an opportunity for a detailed study on the transport and depositional characteristics of a fine-grained, deep-water depositional system. Two phases of resedimentation processes are responsible for deposition of the sediments in the cores and the outcrop. Primary resedimentation processes transport terrigenous sediments from the shelf or basin edge into the middle fan environment, while secondary resedimentation alter the sediments after they are initially deposited in the environment. Debris flows, slurry flows, and high and low density turbidity …


Numerical Solution Of Ocular Fluid Dynamics, Satish Kumar Jan 2003

Numerical Solution Of Ocular Fluid Dynamics, Satish Kumar

LSU Master's Theses

Numerical calculations of the aqueous humor dynamics in the anterior chamber of both the rabbit and the human eye are presented to delineate the basic flow and transport mechanisms. The calculations are based on a geometrical model of the eye, which represents the Trabecular mesh (TM) as a multi-layered porous zone of specified pore sizes and void fraction. Buoyancy is observed to be the dominant driving mechanism for the convective motion in both orientations (horizontal and vertical) of the eye. Reducing the TM pore size does not appear to have a significant influence on the intra-ocular pressure (IOP) until the …


Optimal Batch Quantity Models For A Lean Production System With Rework And Scrap, Pablo Biswas Jan 2003

Optimal Batch Quantity Models For A Lean Production System With Rework And Scrap, Pablo Biswas

LSU Master's Theses

In an imperfect manufacturing process, the defective items are produced with finished goods. Rework process is necessary to convert those defectives into finished goods. As the system is not perfect, some scrap is produced during this process of rework. In this research, inventory models for a single-stage production process are developed where defective items are produced and reworked, where scrap is produced, detected and discarded during the rework. Two policies of rework processes are considered (a) First policy: rework is done within the cycle, and (b) Second policy: rework is done after N cycles of normal production. Also, three types …


Middle Miocene Grounding Events On The Ross Sea Outer Continental Shelf, Antarctica, Juan Manuel Chow Jan 2003

Middle Miocene Grounding Events On The Ross Sea Outer Continental Shelf, Antarctica, Juan Manuel Chow

LSU Master's Theses

The middle Miocene δ18O enrichments from deep-sea data and eustatic sea level falls are traditionally attributed to expansion of the East Antarctic Ice Sheet. Interpretations of such data have led many to conclude that the West Antarctic Ice Sheet (WAIS) was not well-developed until the late Miocene. In such a scenario, middle Miocene glaciation on the Ross Sea shelf would have had to be minimal, perhaps in the form of ice caps, to be consistent with proxy data. New seismic-stratigraphic analysis of the Ross Sea outer continental shelf suggests that at least five grounding events (ice sheet advances …


A Parametrization Approach For Solving The Hamilton-Jacobi-Equation And Application To The A2 Toda Lattice, Mohammad Dikko Aliyu Jan 2003

A Parametrization Approach For Solving The Hamilton-Jacobi-Equation And Application To The A2 Toda Lattice, Mohammad Dikko Aliyu

LSU Master's Theses

Hamilton-Jacobi (HJ)-theory is an extension of Lagrangian mechanics and concerns itself with a directed search for a coordinate transformation in which the equations of motion can be easily integrated. The equations of motion of a given mechanical system can often be simplified considerably by a suitable transformation of variables such that all the new position and momemtum coordinates are constants. A particular type of transformation is chosen in such a way that the new equations of motion retain the same form as in the former coordinates; such a transformation is called canonical or contact and can greatly simplify the solution …


Computer Assisted Eye Fungal Infection Diagnosis, Madhusudhanan Balasubramanian Jan 2003

Computer Assisted Eye Fungal Infection Diagnosis, Madhusudhanan Balasubramanian

LSU Master's Theses

In this thesis, an attempt has been made to assist the diagnosis of Fungal Keratitis, a fungal infection that occurs in the corneal layers of the eye, by identifying the region of infection in the corneal images using fractal-based features. Three features related to the fractal dimension of the surface of the image, when represented in a 3D using the pixel intensity measure, are used to identify these regions in the image. To reduce the computation complexity, Fisher linear discriminant (FLD) is used to reduce the 3D raw feature to 1D feature, while preserving feature values. Using the adaptive mixtures …


Factors Affecting Participation In City Recycling Programs, Stacy Marie Lockhart Jan 2003

Factors Affecting Participation In City Recycling Programs, Stacy Marie Lockhart

LSU Master's Theses

Recycling consists of diverting or recovering materials from the solid waste stream that would otherwise end up returning to the environment as a potential source of pollution. These collected materials are then used as raw materials in the manufacture or assembly of a new product or package. Over the years the amount of municipal solid waste being generated per person has steadily increased. Waste disposal costs are also increasing, making recycling even more important. To address this issue cities are developing recycling policies or plans. The type of plan varies according to the area; as of this time there are …


Low Salinity Waters In Deep Sedimentary Basins, David Scott Szalkowski Jan 2003

Low Salinity Waters In Deep Sedimentary Basins, David Scott Szalkowski

LSU Master's Theses

While the composition and origin of brines in deep sedimentary basins has been extensively discussed, the composition and origin of low salinity waters is not as well documented. Since the 1960s, the presence of deep, low-salinity waters has been observed in some sedimentary basins and is commonly present in overpressured sections. The episodic release of low salinity, overpressured fluids upward into sediments containing high salinity formation waters likely occurs at <100-year intervals. Because there is a growing body of evidence that suggests mixing formation waters of varying salinity could induce the dissolution and precipitation of minerals, it is important to have detailed information about chemical compositions of both end-member fluids to adequately predict such mixing results. This study concludes that low salinity waters (<35 g/l) are generally not unique in major solute composition when compared to high salinity waters (>35 g/l). On log-log plots, monovalent cations plot along 1:1 slopes with respect to salinity and total anionic charge, while divalent cations plot along 2:1 slopes. However, this study concludes …


Sensory Characteristics Of Flavored Milk Candies, Noemi Raquel Pavon Jan 2003

Sensory Characteristics Of Flavored Milk Candies, Noemi Raquel Pavon

LSU Master's Theses

A natural milk candy, composed mainly of milk powder, has not been commercially sold in the U. S. market. The milk candy we developed contains calcium and other essential nutrients, which make it a potential food supplement for adults and children. This thesis research was designed to characterize sensory properties of flavored milk candies and to determine the consumer sensory profile driving product acceptance and purchase intent. A descriptive trained panel (n=12) developed a lexicon and evaluated 3 milk candies (plain, chocolate, and coffee) in triplicate using a 15-cm line scale. 335 adult consumers evaluated acceptability of appearance, size/shape, texture, …


Evaluation Of Repeated Removal Of Mammalian Predators On Waterfowl Nest Success And Density, Kristen Dawn Chodachek Jan 2003

Evaluation Of Repeated Removal Of Mammalian Predators On Waterfowl Nest Success And Density, Kristen Dawn Chodachek

LSU Master's Theses

Low levels of nest success in the prairie pothole region are mainly attributed to changes in predator community and abundance. Removal of predators from large sites (≥ 4144 ha) has been an effective strategy for increasing nest success; however, trapping small sites (< 301 ha) is considered ineffective. I examined the effects of removing predators from 10, 259 ha sites in northeastern North Dakota during 2001-2002. Overall nest success for both years was greater on trapped sites (53.4%) than non-trapped sites (28.7%). Furthermore, daily survival rate was greater on removal sites, and was positively correlated with total predators removed. Differences in nest density were apparent between treatments with an increased nest density on trapped sites, however year had no effect. Pair densities did not differ between treatments, but a 2-fold increase for both trapped and non-trapped sites was found in spring 2002. Cost to produce one fledged duckling, combining all species ranged from $16-20. Overall, the results of this study indicate that repeated removal of predators on small sites is an effective strategy for increasing waterfowl production; however, feasibility will ultimately depend on the user group, budget limitations, landowner objectives, and public acceptance.


Abundance Trends And Environmental Habitat Usage Patterns Of Bottlenose Dolphins (Tursiops Truncatus) In Lower Barataria And Caminada Bays, Louisiana, Cara Edina Miller Jan 2003

Abundance Trends And Environmental Habitat Usage Patterns Of Bottlenose Dolphins (Tursiops Truncatus) In Lower Barataria And Caminada Bays, Louisiana, Cara Edina Miller

LSU Doctoral Dissertations

The paucity of research into the environmental requirements, stock membership, abundance and residency patterns of bottlenose dolphins (Tursiops truncatus) in coastal Louisiana creates difficulty in understanding how local ecosystems and threats (such as fishery interactions, habitat degradation and pollution) affect populations. This study combined fine-scale environmental measurements and photo-identification techniques to describe patterns of habitat usage and abundance of bottlenose dolphins in lower Barataria Basin from June 1999 to May 2002. In addition I investigated the validity and limitations of using mark-recapture models to estimate abundance from cetacean photo-identification data. Bottlenose dolphins were present year-round in a wide range of …


Gauss' Method Of Least Squares: An Historically-Based Introduction, Belinda B. Brand Jan 2003

Gauss' Method Of Least Squares: An Historically-Based Introduction, Belinda B. Brand

LSU Master's Theses

This work presents Gauss' justification of the method of least squares, following the treatment given by Gauss himself in "Theoria Combinationis Observationum Erroribus Minimis Obnoxiae," where the main idea is to show that the least squares estimate is the unbiased linear estimate of minimum variance. (Actually, we present Gauss' argument both in his terminology and translated into matrix terminology.) We show how this contrasts with Gauss' earlier justfication in "Theoria Motus Corporum Coelestium" which was based on the assumption of a normal distribution of errors, and yielded the estimate of maximum likelihood. We present as a background the development from …


A Hybrid Model-Based And Memory-Based Short-Term Traffic Prediction System, Ciprian Danut Alecsandru Jan 2003

A Hybrid Model-Based And Memory-Based Short-Term Traffic Prediction System, Ciprian Danut Alecsandru

LSU Master's Theses

Short-term traffic forecasting capabilities on freeways and major arterials have received special attention in the past decade due primarily to their vital role in supporting various travelers' trip decisions and traffic management functions. This research presents a hybrid model-based and memory-based methodology to improve freeway traffic prediction performance. The proposed methodology integrates both approaches to strengthen predictions under both recurrent and non-recurrent conditions. The model-based approach relies on a combination of static and dynamic neural network architectures to achieve optimal prediction performance under various input and traffic condition settings. Concurrently, the memory-based component is derived from the data archival system …


An Ecopath/Ecosim Analysis Of An Estuarine Food Web: Seasonal Energy Flow And Response To River-Flow Related Perturbations, Laura Lynette Althauser Jan 2003

An Ecopath/Ecosim Analysis Of An Estuarine Food Web: Seasonal Energy Flow And Response To River-Flow Related Perturbations, Laura Lynette Althauser

LSU Master's Theses

Estuaries are often the receiving basins for major river systems which makes them vulnerable to anthropogenic influences. I used Ecopath and Ecosim to investigate the structure of the Weeks Bay, Alabama, USA food web, and the responses of the food web to bottom-up perturbations. Four season-specific steady-state Ecopath models were developed and used to compare the production, biomass, consumption, biomass flows, and higher order indices of ecosystem functioning of the Weeks Bay food web under winter, spring, summer, and fall conditions. The season-specific Ecopath snapshots indicated that the structure of the Weeks Bay food web was resilient. Winter had the …


Regional Water Quality Models For The Prediction Of Eutrophication Endpoints, Anindita Das Jan 2003

Regional Water Quality Models For The Prediction Of Eutrophication Endpoints, Anindita Das

LSU Master's Theses

Eutrophication is a process by which a waterbody progresses from its origin to its extinction. During this period, there is a gradual accumulation of nutrients and organic biomass, accompanied by a decrease in average depth of the water due to sediment accumulation, and an increase in primary productivity, usually in the form of dense algal blooms. Cultural eutrophication occurs when humans, through their various activities, greatly accelerate this process. Eutrophication can cause loss in species diversity, fish kills, and decrease the aesthetic value of a waterbody. The EPA is trying to prevent cultural eutrophication by setting standards for water quality …


Orthogonal Frequency Division Multiplexing Modulation And Inter-Carrier Interference Cancellation, Yao Xiao Jan 2003

Orthogonal Frequency Division Multiplexing Modulation And Inter-Carrier Interference Cancellation, Yao Xiao

LSU Master's Theses

The Orthogonal Frequency Division Multiplexing (OFDM) technique, wireless channel models, and a pair of new intercarrier interference self-cancellation methods are investigated in this thesis. The first chapter addresses the history of OFDM, along with its principles and applications. Chapter two consists of three parts: the principal, the modern OFDM models, and the Peak to Average Power Ratio (PAPR) problem. Chapter two also summarizes possible PAPR solutions. Chapter three discusses a series of well-known wireless channel models, as well as the general formula for wireless channels. In Chapter four, ICI problem has been discussed, along with its existing solutions. Chapter five …


Scalable Parallel Molecular Dynamics Algorithms For Organic Systems, Satyavani Vemparala Jan 2003

Scalable Parallel Molecular Dynamics Algorithms For Organic Systems, Satyavani Vemparala

LSU Master's Theses

A scalable parallel algorithm, Macro-Molecular Dynamics (MMD), has been developed for large-scale molecular dynamics simulations of organic macromolecules, based on space-time multi-resolution techniques and dynamic management of distributed lists. The algorithm also includes the calculation of long range forces using Fast Multipole Method (FMM). FMM is based on the octree data structure, in which each parent cell is divided into 8 child cells and this division continues until the cell size is equal to the non-bonded interaction cutoff length. Due to constant number of operations performed at each stage of the octree, the FMM algorithm scales as O(N). Design and …