Digital Commons Network^™

Reverberation Reduction In A Room For Multiple Positions, Raghavendra Ravikumar

Masters Theses

"Reverberation in a room occurs when the direct path sound from a sound source undergoes multiple reflections from the walls of the room before reaching the listener. An impulse response of the room can be measured called the room impulse response (RIR) which captures the effects of the room. This can be represented digitally on a computer. A filter is designed to cancel the effects of the room using the information in the room impulse response. This filter is called an equalization filter and is usually placed between the source signal and loudspeaker to perform the equalization. The RIR changes …

Quantification Of Uncertainty In Aerodynamic Heating Of A Reentry Vehicle Due To Uncertain Wall And Freestream Conditions, Benjamin R. Bettis

Masters Theses

"The primary focus of this study is to demonstrate an efficient approach for uncertainty quantification of surface heat flux to the spherical non-ablating heatshield of a generic reentry vehicle due to epistemic and aleatory uncertainties that may exist in various parameters used in the numerical solution of hypersonic, viscous, laminar blunt-body flows with thermo-chemical non-equilibrium. Two main uncertainty sources were treated in the computational fluid dynamics (CFD) simulations: (1) aleatory uncertainty in the freestream velocity and (2) epistemic uncertainty in the recombination efficiency for a partially catalytic wall boundary condition. The Second-Order Probability utilizing a stochastic response surface obtained with …

Strategic Process Integration Of Energy And Environmental Systems In Wastewater Treatment Plants, Bharath Kumar Gangichetty

Masters Theses

"Green environmental practices are increasingly important in combating serious global energy and environmental issues. Most wastewater treatment facilities were built when energy costs were not a concern; however, an increasing demand for energy, changing climatic conditions, and constrained energy supplies have resulted in the need to apply more energy-conscious choices in the maintenance or upgrade of existing wastewater treatment facilities. A detailed analysis of the majority of water and wastewater treatment services shows that most facilities operate far below the efficiency levels needed for effective energy use. Failure to comply with regulated environmental standards is also a problem. Although standards …

Strategic Criteria For Evaluating Inland Freight Hub Locations, Robert Tyler Lipscomb

Masters Theses

"The aim of this thesis is to develop criteria that can be used to evaluate the current capabilities and sustainability of inland freight hubs. A review of the literature highlights the need for a more efficient freight distribution system to combat supply chain deficiencies and the important role that inland freight hubs play in creating this system. Also in the literature is a call for a more comprehensive approach to hub development decisions and the use of multi-criteria decision analysis. The decision to devote resources to logistics developments in a specific region must consider many factors that are both quantitative …

A Value Model For Product Development Process Using Lean Principles, Salik Yadav

Masters Theses

"This research presents a value quantification model for multi-stage product development Process (PDP) using lean value principles. The PDP stages considered in this research include conceptual development, systems design, detailed design and prototyping stages. The value at any of the PDP stages is formulated as a function of six factors: (a) importance of customer requirements, (b) cost of customer's ownership, (c) parts/service availability, (d) weighted average cost of capital, (e) information evolution, and (f) risk reduction. Factors (a)-(d) are adequately addressed in the literature. This study focuses on information evolution and risk reduction factors. These two factors are defined by …

The Mitigation Effects Of A Barrier Wall On Blast Wave Pressures, Nathan Thomas Rouse

Masters Theses

"The study examined the mitigating effects of a blast barrier wall. This area of blast mitigation is of interest due to the many different applications involved in protecting a specific target from an explosive attack. The research follows a 1:50 scale layout using 73 gram, hemisphere-shaped, Composition-4 charges detonated at combinations of three standoff distances from a blast barrier wall set at three different heights. This project used 45 data points for each combination of standoff distance and wall height. This project expanded prior research conducted by the United States Army Corps of Engineers (USACE) by increasing the database of …

Population Control In Evolutionary Algorithms, Jason Edward Cook

Masters Theses

"Traditional evolutionary algorithms (EAs) are powerful robust problem solvers that have several fixed parameters which require prior specification. Having to determine good values for any of these parameters can be problematic, as the performance of EAs is generally very sensitive to these parameters, requiring expert knowledge to set optimally without extensive use of trial and error. Parameter control is a promising approach to achieving this automation and has the added potential of increasing EA performance based on both theoretical and empirical evidence that the optimal values of EA strategy parameters change during the course of executing an evolutionary run. While …

Data Aggregation In Wireless Sensor Networks, Priya Kasirajan

Masters Theses

"Energy efficiency is an important metric in resource constrained wireless sensor networks (WSN). Multiple approaches such as duty cycling, energy optimal scheduling, energy aware routing and data aggregation can be availed to reduce energy consumption throughout the network. This thesis addresses the data aggregation during routing since the energy expended in transmitting a single data bit is several orders of magnitude higher than it is required for a single 32 bit computation. Therefore, in the first paper, a novel nonlinear adaptive pulse coded modulation-based compression (NADPCMC) scheme is proposed for data aggregation. A rigorous analytical development of the proposed scheme …

Multi Axis Slicing For Rapid Prototyping, Divya Kanakanala

Masters Theses

"With multi-axis capability, direct laser deposition process can produce a metal part without the usage of support structures. In order to fully utilize such a capability, a slicing method for multi-axis metal deposition process is discussed. Using the geometry information of adjacent layers, the slicing direction and layer thickness can be changed as needed. A hierarchy structure is designed to manage the topological information which is used to determine the slicing sequence. The parallel slicing process is studied to build hollow type structure. With such a character, the hole like feature can be deposited directly to save the required machining …

Inverse Limits With Upper Semi-Continuous Set Valued Bonding Functions: An Example, Christopher David Jacobsen

Masters Theses

"While there is a wealth of information pertaining to inverse limits with single valued bonding maps, comparatively little is known about inverse limits with upper semi-continuous set valued bonding functions. In order to add somewhat to the communal knowledge on the subject, this paper provides an example of an inverse limit with a single upper semi-continuous set valued bonding function. It is then shown that the space is a continuum, and its structure is examined via its arc components and through various of its properties, such as dimension and decomposability"--Abstract, page iii.

Contribution-Based Priority Assessment In A Web-Based Intelligent Argumentation Network For Collaborative Software Development, Maithili Satyavolu

Masters Theses

"Decision making is an important aspect of the collaborative software development process which usually involves complex process of conflict resolution. Stakeholders approach decision making process from multiple perspectives and their priorities play a vital role in it. The priority assessment methods used in the argumentation process so far are usually static. Priorities remain constant throughout the decision making process. In order to make the collaborative system more closely replicate real-world scenarios, this work incorporates dynamic priority assessment into a web-based collaborative system which is based on intelligent computational argumentation. It evaluates priorities dynamically for each cycle of decision process based …

Corrosion Resistance Of Enamel-Coated Steel Reinforcement For Concrete, Charles Robert Werner

Masters Theses

"Originally developed to enhance the bond between concrete and steel, reactive enamel coatings have shown great promise in protecting steel from corrosive environments. However, the corrosion resistance of the material has not yet been tested beyond 40 days. Moreover, when the material was tested, it was applied to smooth steel pins, not deformed steel bars which are commonly used in reinforced concrete structures. Therefore, this study focused on the corrosion resistance of three different enamel coatings, along with a standard epoxy coating, each of which were applied to both smooth and deformed steel bars and included both short-term and long-term …

Adaptive Resource Allocation For Cognitive Wireless Ad Hoc Networks, Behdis Eslamnour

Doctoral Dissertations

"Widespread use of resource constrained wireless ad hoc networks requires careful management of the network resources in order to maximize the utilization. In cognitive wireless networks, resources such as spectrum, energy, communication links/paths, time, space, modulation scheme, have to be managed to maintain quality of service (QoS). Therefore in the first paper, a distributed dynamic channel allocation scheme is proposed for multi-channel wireless ad hoc networks with single-radio nodes. The proposed learning scheme adapts the probabilities of selecting each channel as a function of the error in the performance index at each step.

Due to frequent changes in topology and …

Intelligent Power System Operation In An Uncertain Environment, Yusuf Yare

Doctoral Dissertations

"This dissertation presents some challenging problems in power system operations. The efficacy of a heuristic method, namely, modified discrete particle swarm optimization (MDPSO) algorithm is illustrated and compared with other methods by solving the reliability based generator maintenance scheduling (GMS) optimization problem of a practical hydrothermal power system. The concept of multiple swarms is incorporated into the MDPSO algorithm to form a robust multiple swarms-modified particle swarm optimization (MS-MDPSO) algorithm and applied to solving the GMS problem on two power systems. Heuristic methods are proposed to circumvent the problems of imposed non-smooth assumptions common with the classical approaches in solving …

Spatial And Temporal Patterns In Nitrous Oxide Flux From Agricultural Soil In Southern Ontario, Michelle E. Zurbrigg

Theses and Dissertations (Comprehensive)

This research examines spatial and temporal variations in N₂O flux from agricultural clay loam in corn-wheat and corn-oat rotations in southern Ontario. Gas samples are collected by the chamber method following significant precipitation events, thaw events, fertilization events, and otherwise every two weeks over a two-year period. Crop type appears to influence the magnitude of N₂O emisions, whereas N₂O fluxes do not otherwise seem to vary by landscape position. The seasonal pattern of in situ N₂O flux at Strawberry Creek (SC) indicates that the highest N₂O emissions are occuring during …

Computational And Theoretical Aspects Of N-E.C. Graphs, Alexandru Costea

Theses and Dissertations (Comprehensive)

We consider graphs with the n-existentially closed adjacency property. For a positive integer n, a graph is n-existentially closed (or n-e.c.) if for all disjoint sets of vertices A and B with \A∪ B\ = n (one of A or B can be empty), there is a vertex 2 not in A∪B joined to each vertex of A and no vertex of B. Although the n-e.c. property is straightforward to define, it is not obvious from the definition that graphs with the property exist. In 1963, Erdos and Rényi gave …

Financial Securities Under Nonlinear Diffusion Asset Pricing Model, Andrey Vasilyev

Theses and Dissertations (Comprehensive)

In this thesis we investigate two pricing models for valuing financial derivatives. Both models are diffusion processes with a linear drift and nonlinear diffusion coefficient. The forward price process of these models is a martingale under an assumed risk-neutral measure and the transition probability densities are given in analytically closed form. Specifically, we study and calibrate two different families of models that are constructed based on a so-called diffusion canonical transformation. One family follows from the Ornstein-Uhlenbeck diffusion (the UOU family) and the other—from the Cox-Ingersoll-Ross process (the Confluent-U family).

The first part of the thesis considers single-asset and multi-asset …

Isolation And Characterization Of Ligands For The Goldfish Testicular Androgen Receptor From Kraft Mill Chemical Recovery Condensates, Philip David Scott

Theses and Dissertations (Comprehensive)

An investigation of cause was started in the 1990s at a bleached Kraft mill (BKM), located in Saint John NB, Canada. The 5th effect chemical recovery condensates waste stream (derived from wastewater generated during the pulping process) was identified as having the greatest potential for affecting mummichog (Fundulus heteroclitus), compared to the rest of the inmill waste streams. A solid phase extraction (SPE) protocol was utilized to isolate the causative chemicals in the condensate stream. Goldfish testicular androgen receptors (ARs) were exposed to five extracts: filter paper non-polar/polar, solid phase extraction nonpolar/polar, and residual condensates. The filter paper …

Microporous Organic Polymers: Synthesis And Post Synthetic Modifications, Phillip Andrew Kerneghan

Theses and Dissertations (Comprehensive)

Microporous solids are an important class of materials that have been studied extensively. Newer to this field are Microporous Organic Polymers (MOPs) which are networks constructed from smaller organic building blocks and exhibit large surface areas, small pore sizes and low densities. It is due to these characteristics that MOPs have attracted attention because of their potential use in applications such as catalysis, chemical separations and gas storage.

In this thesis is described the synthesis of two novel MOPs, the first of which being a network based on benzenediboronic acid and triptycene building blocks linked together by boronate esters. This …

Plant Isotopes As Indicators Of N Cycling Processes In Agricultural Fields, Eric Thuss

Theses and Dissertations (Comprehensive)

When nitrogen (N) availability exceeds biological demand, excess N, especially nitrate (NO₃), may subsequently pollute ground and surface water. Agricultural practices in Southern Ontario typically supplement soils with organic and inorganic nutrients to aid in crop development, and employ various management techniques to limit nutrient loss. Excess N has several potential fates, which are controlled by the net effects of numerous N cycling reactions in the soil that are often difficult to measure directly. N cycling in soils is controlled in large part by soil moisture, as it affects microbial activity and soil redox conditions. Stable isotope geochemistry …

Carbon Dioxide Exchange In A Permafrost-Dominated Boreal Wetland In The Northwest Territories, Canada, Andrea J. Kenward

Theses and Dissertations (Comprehensive)

Northern boreal wetland complexes are substantial reservoirs for carbon and play a crucial role in both regional and global carbon budgets but they are showing significant signs of impact by climate change. This study examined the carbon dioxide flux of a high boreal wetland during the snowmelt and growing season of 2008 in Scotty Creek Basin, located near Fort Simpson (61°18'N, 121°18'W), Northwest Territories. This basin is not only responding to shifts in atmospheric temperatures, but it is also under additional pressure from increasing permafrost degradation. A dynamic closed-system chamber was used to monitor and quantify mid-day total respiration (R …

Mathematical Modeling And Control Of Nonlinear Oscillators With Shape Memory Alloys, Mohamed Bendame

Theses and Dissertations (Comprehensive)

Shape memory alloys (SMAs) belong to an interesting type of materials that have attracted the attention of scientists and engineers over the last few decades. They have some interesting properties that made them the subject of extensive research to find the best ways to utilize them in different engineering, biomedical, and scientific applications. In this thesis, we develop a mathematical model and analyze the behavior of SMAs by considering a one degree of freedom nonlinear oscillator consisting of a mass connected to a fixed frame through a viscous damping and a shape memory alloy device. Due to the nonlinear and …

Insights Into Genome Functional Organisation Through The Analysis Of Interaction Networks, Andre Masella

Theses and Dissertations (Comprehensive)

Using computational techniques to identify orthology and operon structure, it is possible to find functional interactions between genes, which, together, define the genetic interactome. These large networks contain information about the relationships between phenotypes in organisms as genes responsible for related abilities are often co-regulated and reasserting of these genes can be detected in the operon structure. However, these networks are too large to analyse by hand In order to practically analyse the networks, a computational tool, gisql, was developed and, using this tool, the connectivity patterns in the genetic interactome can be analysed to understand high-level organisation of …

Water Analysis For Emerging Environmental Contaminants, Xiaoliang Cheng

Masters Theses

"The presence of emerging environmental contaminants in water bodies used either as drinking water or for recreational purpose has received considerable attention in the recent years. The emerging environmental contaminants can be defined as a wide range of chemicals that have been determined in the environment which may present serious health risks for humans. The occurrence of these contaminants indicate that both household and industrial chemicals have been introduced to water resources, a wide variety of chemicals, such as disinfection byproducts, pharmaceutical and personal care products and so on, have been detected at cetiain levels in either water bodies or …

Automation Of Cad Model Based Assembly Simulations Using Motion Capture, Anup Madhav Vader

Masters Theses

"The manufacturing industry often uses text and video as a supplement for worker training procedures. Unfortunately, text is often difficult to follow and video lends itself to occlusion issues. CAD based animations of assembly operations can overcome these shortcomings while offering greater potential for operations analysis and simulation flexibility. However, creating such CAD based training simulations manually is a time intensive task and many a times fail to reveal the practical assembly issues faced in the real world. Thus, it is highly beneficial to be able to automate these simulations using motion capture from a physical environment. This thesis research …

Developing A Model For Evaluating Software Tools In Education, Vedant Jain

Masters Theses

"This thesis proposes a research model to evaluate computer-mediated learning technology, user acceptance of the technology, and the effect of the technology on learning outcomes. This thesis also introduces two innovative research techniques for such evaluations, that is, eye-tracking and the think aloud protocol. Think aloud protocol allows us to understand a user's state of mind while he/she is interacting with the system. Eye-tracking provides additional insights into a user's cognitive state while using the system and can help triangulate the results. We demonstrated the application of the research model and research techniques in evaluating visualization software designed in a …

Palynology Of The Middle To Upper Eocene Esmeraldas Formation In The Nuevo Mundo Syncline Area, Middle Magdalena Valley Basin, Colombia, Guillermo Rodriguez-Forero

Masters Theses

"The palynology of the Eocene Esmeraldas Formation in the Middle Magdalena Valley Basin, Colombia was analyzed in order to constrain the age of the unit. This formation is a very important oil reservoir in the Middle Magdalena Valley Basin, which is a product of a fragmentation of a Cenozoic foreland basin by the Northern Andes. It created structural complexities and syntectonic deposition. The lateral continuity of the formation, as well as its correlations with lithostratigraphic units is adjacent basins, are not clearly understood. The Los Corros Fossil Horizon, a mollusk horizon in the upper part of the Esmeraldas Formation, is …

An Artificial Life Approach To Evolutionary Computation: From Mobile Cellular Algorithms To Artificial Ecosystems, Shivakar Vulli

Masters Theses

"This thesis presents a new class of evolutionary algorithms called mobile cellular evolutionary algorithms (mcEAs). These algorithms are characterized by individuals moving around on a spatial population structure. As a primary objective, this thesis aims to show that by controlling the population density and mobility in mcEAs, it is possible to achieve much better control over the rate of convergence than what is already possible in existing cellular EAs. Using the observations and results from this investigation into selection pressure in mcEAs, a general architecture for developing agent-based evolutionary algorithms called Artificial Ecosystems (AES) is presented. A simple agent-based EA …

Detection And Estimation Of Image Blur, Harish Narayanan Ramakrishnan

Masters Theses

"The airborne imagery consisting of infrared (IR) and multispectral (MSI) images collected in 2009 under airborne mine and minefield detection program by Night Vision and Electronic Sensors Directorate (NVESD) was found to be severely blurred due to relative motion between the camera and the object and some of them with defocus blurs due to various reasons. Automated detection of blur due to motion and defocus blurs and the estimation of blur like point spread function for severely degraded images is an important task for processing and detection in such airborne imagery. Although several full reference and reduced reference methods are …

Zinc Iron Phosphate Glasses For Enameling Applications, Sagnik Saha

Masters Theses

"New compositions of low temperature black glasses were developed that are suitable as frits for enameling soda-lime silicate (S-L-S) glass substrates. Zinc iron phosphate glasses are of interest for this application because they possess dilatometric low softening points (under 600ºC) and have coefficients of thermal expansion that are compatible with S-L-S glass (in the range 90-110x10⁻⁷/ºC). The development of compositions with excellent chemical durability, particularly in acidic conditions, is also desired. Compositional modification were made to the (Na₂O+K₂O)·ZnO·MnO·Fe₂O₃·P₂O₅ glass system using design of experiments. The compositional boundaries used in the design were based on earlier work at Missouri S&T. The …