Physical Sciences and Mathematics Commons^™

Evaluating Rhizodegradation Of Petroleum Hydrocarbons And Polycyclic Aromatic Hydrocarbons In Wetland Sediments Containing Spartina Patens, Robert J. Lippencott

Dissertations

Biodegradation of petroleum hydrocarbons (PHC) and 16 polycyclic aromatic hydrocarbon (PAH) compounds was evaluated in sediments from a stormwater basin that was a former salt marsh at an active oil refinery. Spartina patens were grown in basin sediments during a field study and a greenhouse study over three consecutive growing seasons. Ninety percent (90%) survival was observed in field study plots containing sediments with <12% PHC. In the greenhouse study, planted and bulk sediments were monitored for PHC, PAH, microbial density, nutrients, pH, redox and root biomass at 2.5 and 7.5 cm in sediments with <12% PHC. The sediments contained on average 6.5% to 9.5% PHC and 56 to 124 parts per million (ppm) total PAH. The plants exhibited a 95% survival rate and added from 1% to 2% root biomass to the sediment. Microbial densities in planted sediments were significantly higher than in bulk sediments (p<0.05). Oxidizing conditions were prevalent in all treatments at both depths; however, reducing conditions developed in the planted sediments at 7.5 cm. PHC was 35% to 37% lower in the planted sediments vs. bulk sediment at the end of the study. Planted sediment PAH concentrations were generally lower than in bulk sediments. Low MW PAHs (2 and 3-Rings) were either absent or at relatively low concentrations in all treatments. Phenanthrene concentrations in bulk sediments did not change, but were reduced by 95% in planted sediments (p<0.01), with half-life estimates of 141 to 165 days at 2.5 cm. Temporal changes in high MW PAHs ( 4-Rings) were not observed over the greenhouse study period. Differences in PAH concentrations between planted and bulk sediments exhibited a decreasing trend with PAH molecular weight. Evaluation of differences in planted and bulk sediment PAH concentrations suggests that lower MW PAHs degrade better under oxidizing conditions, and higher MW PAHs under reducing conditions in the planted sediments. Comparison of planted and bulk sediment PAH concentrations links depth and redox conditions to decreases in PAH as a function of PAH MW. Therefore, it was concluded that spatio-temporal variations and cycling of redox conditions should be considered to properly evaluate biodegradation of PAH.

Theory And Algorithms For Swept Manifold Intersections, Yuriy Mileyko

Dissertations

Recent developments in such fields as computer aided geometric design, geometric modeling, and computational topology have generated a spate of interest towards geometric objects called swept volumes. Besides their great applicability in various practical areas, the mere geometry and topology of these entities make them a perfect testbed for novel approaches aimed at analyzing and representing geometric objects. The structure of swept volumes reveals that it is also important to focus on a little simpler, although a very similar type of objects - swept manifolds. In particular, effective computability of swept manifold intersections is of major concern.

The main goal …

Scheduling Policies For Disks And Disk Arrays, Chang Liu

Dissertations

Recent rapid advances of magnetic recording technology have enabled substantial increases in disk capacity. There has been less than 10% improvement annually in the random access time to small data blocks on the disk. Such accesses are very common in OLTP applications, which tend to have stringent response time requirements. Scheduling of disk requests is intended to improve their response time, reduce disk service time, and increase disk access bandwidth with respect to the default FCFS scheduling policy.

Shortest Access Time First policy has been shown to outperform other classical disk scheduling policies in numerous studies. Before verifying this conclusion, …

Image Watermarking, Steganography, And Morphological Processing, Yi-Ta Wu

Dissertations

With the fast development of computer technology, research in the fields of multimedia security, image processing, and robot vision have recently become popular. Image watermarking, steganogrphic system, morphological processing and shortest path planning are important subjects among them. In this dissertation, the fundamental techniques are reviewed first followed by the presentation of novel algorithms and theorems for these three subjects.

The research on multimedia security consists of two parts, image watermarking and steganographic system. In image watermarking, several algorithms are developed to achieve different goals as shown below. In order to embed more watermarks and to minimize distortion of watermarked …

Collaborative Examinations In Asyncronous Learning Networks : Field Experiments On Collaborative Learning Through Online Assessments, Jia Shen

Dissertations

With the proliferation of computer networks and the emergence of virtual teams, learning and knowledge sharing in the online environment has become an increasingly important topic. Applying constructivism and collaborative learning theories to assessment, the collaborative online exam is designed featuring students' active participation in various phases of the exam process through small group activities online. A participatory online exam process is designed featuring similar procedures except that students' involvement in each phase of the exam is individual. The collaborative online exam and the participatory online exam are investigated regarding student exam study strategies, group process, exam outcomes, faculty satisfaction, …

Electromagnetic And Acoustic Propagation In Strip Lines And Porous Media, Lin Zhou

Dissertations

Wave propagation in two physical structures is described and analyzed in this dissertation. In the first problem, the propagation of a normally incident plane acoustic wave through a three dimensional rigid slab with periodically placed holes is modeled and analyzed. The spacing of the holes A and B, the wavelength λ and the thickness of the slab L are order one parameters compared to the characteristic size D of the holes, which is a small quantity. Scattering matrix techniques are used to derive expressions for the transmission and reflection coefficients of the lowest mode. These expressions depend only on the …

Algorithms And Complexity Analyses For Some Combinational Optimization Problems, Hairong Zhao

Dissertations

The main focus of this dissertation is on classical combinatorial optimization problems in two important areas: scheduling and network design.

In the area of scheduling, the main interest is in problems in the master-slave model. In this model, each machine is either a master machine or a slave machine. Each job is associated with a preprocessing task, a slave task and a postprocessing task that must be executed in this order. Each slave task has a dedicated slave machine. All the preprocessing and postprocessing tasks share a single master machine or the same set of master machines. A job may …

Just-In-Time Hypermedia, Li Zhang

Dissertations

Many analytical applications, especially legacy systems, create documents and display screens in response to user queries "dynamically" or in real time . These documents and displays do not exist in advance, and thus hypermedia must be generated 'just in time" -automatically and dynamically.

This dissertation details the idea of 'just-in-time" hypermedia and discusses challenges encountered in this research area. A fully detailed literature review about the research issues and related research work is given. A framework for the 'just-in-time" hypermedia compares virtual documents with static documents, as well as dynamic with static hypermedia functionality. Conceptual 'just-in-time" hypermedia architecture is proposed …

High-Dimensional Indexing Methods Utilizing Clustering And Dimensionality Reduction, Lijuan Zhang

Dissertations

The emergence of novel database applications has resulted in the prevalence of a new paradigm for similarity search. These applications include multimedia databases, medical imaging databases, time series databases, DNA and protein sequence databases, and many others. Features of data objects are extracted and transformed into high-dimensional data points. Searching for objects becomes a search on points in the high-dimensional feature space. The dissimilarity between two objects is determined by the distance between two feature vectors. Similarity search is usually implemented as nearest neighbor search in feature vector spaces. The cost of processing k-nearest neighbor (k-NN) queries via a sequential …

Improving Document Representation By Accumulating Relevance Feedback : The Relevance Feedback Accumulation (Rfa) Algorithm, Razvan Stefan Bot

Dissertations

Document representation (indexing) techniques are dominated by variants of the term-frequency analysis approach, based on the assumption that the more occurrences a term has throughout a document the more important the term is in that document. Inherent drawbacks associated with this approach include: poor index quality, high document representation size and the word mismatch problem. To tackle these drawbacks, a document representation improvement method called the Relevance Feedback Accumulation (RFA) algorithm is presented. The algorithm provides a mechanism to continuously accumulate relevance assessments over time and across users. It also provides a document representation modification function, or document representation learning …

The Control Of Frequency Of A Conditional Oscillator Simultaneously Subjected To Multiple Oscillatory Inputs, Christina L. Ambrosio

Dissertations

A conditional oscillator is one that requires input to oscillate. An example of such is the gastric mill network of the stomatogastric ganglion of the crab Cancer borealis which requires modulatory input from outside the stomatogastric ganglion and fast input from the pyloric network of the animal in order to become active. This dissertation studies how the frequency of the gastric mill network is determined when it is simultaneously subjected to two different rhythmic inputs whose timing may be mismatched. We derive a mathematical model of the gastric mill network and deduce that the difference in timing between the pyloric …

Order Scheduling In Dedicated And Flexible Machine Environments, Haibing Li

Dissertations

Order scheduling models are relatively new in the field of scheduling. Consider a facility with m parallel machines that can process k different products (job types). Each machine can process a given subset of different product types. There are n orders from n different clients. Each order requests specific quantities of the various different products that can be produced concurrently on their given subsets of machines; it may have a release date, a weight and a due date. Preemptions may be allowed. An order can not be shipped until the processing of all the products for the order has been …

Flash Animation Project: Written Report, Peter Dee

Dissertations

A written report about a Flash animation project to include the 3 headings of Animation Techniques, Story Telling and Audio along with a critique and an appendix. The Flash animation project is based upon one of Aesop's fables entitled 'The King's Son & the Painted Lion'.

Structure Preserving Algorithms For Computing The Symplectic Singular Value Decom Position, Archara Chaiyakarn

Dissertations

In this thesis we develop two types of structure preserving Jacobi algorithms for com puting the symplectic singular value decomposition of real symplectic matrices and complex symplectic matrices. Unlike general purpose algorithms, these algorithms produce symplectic structure in all factors of the singular value decomposition.

Our first algorithm uses the relation between the singular value decomposition and the polar decomposition to reduce the problem of finding the symplectic singular value decomposition to th a t of calculating the structured spectral decomposition of a doubly structured m atrix. A Jacobi-like m ethod is developed to compute this doubly structured spectral decomposition. …

Global Optimality Conditions In Mathematical Programming And Optimal Control, Pariwat Pacheenburawaa

Dissertations

We derive new first-order necessary and sufficient optimality conditions characterizing global minimizers in mathematical programming and optimal controlproblems. These conditions are based on level sets of an objective functional and they do not assume special structure of a problem (convexity, linearity, etc.). For a mathematical programming problem of minimization of a smooth functional on some compact convex set with equality nonlinear constraints, we derive first-order optimality conditions in the form of a generalized Lagrange multiplier rule. This rule should hold for any point from the level set of the objective functional corresponding to a global minimizer. We demonstrate that these …

Stratification And Domination In Graphs And Digraphs, Ralucca M. Gera

Dissertations

In this thesis we combine the idea of stratification with the one of domination in graphs and digraphs, respectively.

A graph is 2-stratified if its vertex set is partitioned into two classes, where the vertices in one class are colored red and those in the other class are colored blue. Let F be a 2-stratified graph rooted at some blue vertex v . An F -coloring of a graph G is a red-blue coloring of the vertices of G in which every blue vertexu belongs to a copy of F rooted at u . The F -domination number γ …

Hybrid Explicit-Implicit Fdtd-Fem Time-Domain Solver For Electromagnetic Problems, Kakhkhor Abdijalilov

Dissertations

The Finite-Difference Time-Domain (FDTD) method and Finite-Element (FEM) method are numerical techniques used for solving Maxwell's electromagnetic equations. FDTD-FEM hybrid methods opt for combining the advantages of both FDTD and FEM. In this dissertation, signal processing techniques were used to analyze the FDTD stability condition. A procedure, which reduces time-sampling error yet preserves the stability of algorithm is proposed. Both explicit and implicit time-stepping schemes were treated in the framework of the developed method. An improved version of the implicit-explicit FEM-FDTD hybrid method was developed. The new method minimizes reflection from the interface between different types of grids. A class …

Characteristics Of Nanocomposites And Semiconductor Heterostructure Wafers Using Thz Spectroscopy, Hakan Altan

Dissertations

All optical, THz-Time Domain Spectroscopic (THz-TDS) methods were employed towards determining the electrical characteristics of Single Walled Carbon Nanotubes, Ion Implanted Si nanoclusters and Si_1-xGe_x HFO₂, SiO₂ on p-type Si wafers.

For the nanoscale composite materials, Visible Pump/THz Probe spectroscopy measurements were performed after observing that the samples were not sensitive to the THz radiation alone. The results suggest that the photoexcited nanotubes exhibit localized transport due to Lorentz-type photo-induced localized states from 0.2 to 0.7THz. The THz transmission is modeled through the photoexcited layer with an effective dielectric constant described by a Drude …

Negotiation Of Software Requirements In An Asynchronous Collaborative Environment, Catherine Lowry Campbell

Dissertations

The effect of task structure and negotiation sequence on collaborative software requirements negotiation is investigated. This work began with an extensive literature review that focused on current research in collaborative software engineering and, in particular, on the negotiation of software requirements and the requisite collaboration for the development of such requirements. A formal detailed experiment was then conducted to evaluate the effects of negotiation sequence and task structure in an asynchronous group meeting environment. The experiment tested the impact of these structures on groups negotiating the requirements for an emergency response information system. The results reported here show that these …

Characterizing The Evolution Of Operating Systems, Yi Peng

Dissertations

Examining the development and trends in software engineering technology is a huge undertaking. It is constantly evolving and affected by a large number of factors, which are themselves driven by a wide range of sub-factors. This dissertation is part of a long term project intended to analyze software engineering technology trends and how they evolve. This project is intended to analyze operating system trends and what are the factors that drive how they evolve. Basically, the following questions will be answered: "How to watch, predict, adapt to, and affect operating system's evolution trends?"

In previous research, YF Chen used statistical …

Live, Virtual, And Constructive Environments For Performance Support, John Michael Lacontora

Dissertations

As military systems become more complex, the operation and support of these systems becomes intrinsically more difficult. The U.S. Army's current procurement process relies on industry to provide embedded training and performance support tools for the systems they produce. These tools are relatively new and in the early stages of development. As yet, they have failed to meet the needs of the technicians that are required to support these complex systems. Current efforts to provide enabling technologies that enhance the capabilities of automotive maintenance technicians are concentrated in three professional communities. First is the Performance Improvement community where work is …

Pattern Discovery In Structural Databases With Applications To Bioinformatics, Sen Zhang

Dissertations

Frequent structure mining (FSM) aims to discover and extract patterns frequently occurring in structural data such as trees and graphs. FSM finds many applications in bioinformatics, XML processing, Web log analysis, and so on. In this thesis, two new FSM techniques are proposed for finding patterns in unordered labeled trees. Such trees can be used to model evolutionary histories of different species, among others.

The first FSM technique finds cousin pairs in the trees. A cousin pair is a pair of nodes sharing the same parent, the same grandparent, or the same great-grandparent, etc. Given a tree T, our …

The Testing Of Semiconductor-Based Adsorption Modified Photosensitive Sensors For Their Response To A Volatile Organic Compound, Oxygen, Humidity, And Heating, Roberta Rosty

Dissertations

Two thin-film sensors, composed of different thicknesses (approximately 0.5 microns and 4.5 microns) of a cadmium sulfide layer coated with Rhodamine B fluorescent dye on a glass substrate, were tested for change in photoconductivity due to exposure to different concentrations of gaseous organic molecules in the parts-per-million (ppm) range.

It was theorized that the gaseous organic molecules would adsorb to the dyed semiconductor surface and that some energy would be transferred to the adsorbed analyte rather than to the cadmium sulfide semiconductor layer through the dye, thereby decreasing the photoconductivity of the surface in an amount proportional to the analyte …

Scattering Matrix Analysis Of Photonic Crystals, Valeriy Lukyanov

Dissertations

Using a scattering matrix approach we analyze and study the scattering and transmission of waves through a two-dimensional photonic crystal which consists of a periodic array of parallel rods with circular cross sections. Without making any assumptions about normal incidence, single mode propagation, and sufficient inter-scatter separation in the direction of propagation, we show how to compute the transmission and reflection coefficients of these periodic structures. The method is based on the computation of a generalized scattering matrix for one column of the periodic structure.

We also develop an analytical method to analyze and to study the scattering and transmission …

An Optic Fiber Sensor For Partial Discharge Acoustic Detection, Xiaodong Wang

Dissertations

Partial discharge (PD) is a very common problem in operating power transformers and is one of the factors that could lead to failure of power transformers, leading to power outage and expensive repairs. The acoustic wave induced by PD can be measured and used for monitoring, diagnosing, and locating potential failures in power transformers.

The effects of the temperature of the transformer and transformer oil are one of the very important parameters in PD and these effects are investigated in detail. The Fast Fourier Transform (FF1') is used to synthesize the measured data and results show that for periodic PD …

Two High School Teachers’ Initial Use Of Geometers Sketchpad: Issues Of Implementation, Kathryn G. Shafer

Dissertations

This study documents two teachers' instructional practices as they learn and incorporate Geometer's Sketchpad (GSP) activities into their curriculum. The researcher (as a mentor) worked closely with two high school geometry teachers following a case study methodology. As a secondary goal, this study examined the use of a mentor as a professional development model to assist classroom teachers in the learning and implementation of Geometer'sSketchpad. Data were gathered through interviews, surveys, observations, classroom videotape, participant journal entries, as well as researcher field notes.

Results are reported in the areas of goals of instruction, method of instruction, role of the teacher, …

Analysis Of Benzo(A)Pyrene-Induced Gene Expression Changes In Fisher 344 Rat Liver By Affymetrix Microarray And Quantitative Real-Time Pcr, Alhaji Umar N’Jai

Dissertations

No abstract provided.

The Glacial Geology Of Southern St. Joseph County, Michigan, Linda Nicks

Dissertations

The objective of the dissertation was to map the glacial geology in southern St. Joseph County, Michigan. The surficial geology was divided into three distinct land systems which are moraine, outwash and fan deposits. The Sturgis Moraine is the most prominent feature transecting the study area from east to west. The topography is further dissected by southwest-trending channels interpreted as tunnel channels.

Thick accumulations of sand and gravel in the study area indicate that glacial meltwater deposition played a dominant role in shaping the landscape. Based on the relative size of the channels and outwash deposits, the largest contribution from …

Origin Of The Central Kalamazoo River Valley, Southwestern Michigan, Usa, Andrew Kozlowski

Dissertations

Chapter I

Introduction

Southern Michigan's geomorphology is a testament to the glacial processes that buried and sculpted the landscape during the last glaciation. Many glacial landforms in southwestern Michigan, including the Kalamazoo River Valley, provide evidence that aids in understanding the chronology, ice dynamics and glacial processes that occurred in Michigan during the last ice age.

As the climate began to warm about 20,000 yr B.P. (Larson and Schaetzl, 2001) the extensive Laurentide Ice Sheet began to recede from its maximum southern position reached during the Late Wisconsinan (Figure 1). It was at this point that modem surficial drainage systems …

Phase Coherent Effects In The Speckle Correlation Of Light Scattered Fromvolume Disordered Media And Randomly Rough Surfaces, Bogdan Danila

Dissertations

We present a study of the statistics of the intensity patterns produced when coherent light is scattered by random media (volume disorder) or randomly rough surfaces. Such a random, granular interference pattern is called speckle. Particular emphasis is on the statistical correlations arising between thefluctuations of the intensities corresponding to distinct scattering paths; which are quantified by the speckle correlation function. In the first part, we present results for the correlation function computed for volume-disordered media by means of numerical simulation. Our focus is on the sensitivity of the correlationfunction to statistical parameters characterizing the volume distribution of the refraction …