Digital Commons Network^™

Proof Of Concept Design And Analysis Of Active Flow Control Of A Supersonic Micro-Nozzle, Christopher J. Szachta

Theses

Low Reynolds number supersonic nozzles have been studied for several years due to their significance in applications in micro-spacecraft. As satellite design reduces in mass and size, smaller more versatile propulsion systems will be required. In response to the need, a conical nozzle (expansion ratio of 25 and 20° half-angle of divergence) with throat dimensions of 600µm x 300µm has been designed and fabricated with capabilities in thrust magnitude control. The device utilizes the expansion of a silicone membrane, located on the upper surface of the supersonic micro-nozzle throat, as a mechanism to reduce the throat cross sectional area, and …

Data Limitations Can Be Overcome To Move Toward Effective Business System Integration, Paul G. Ruganis

Theses

Investigation indicates that data quality and consistency issues will continue to be overwhelming impediments to the complete integration of all information systems in the current Information Technology (IT) environment. However, there is evidence that businesses can still move toward an effective "Digital Business Design" (DBD) by focusing on a relatively small number of critical success factors. The possible approaches to integration available in the current IT environment were reviewed to gain insight into candidate design bases available. The DBD implementations of sample firms were examined to explore what aspects of integration they considered in their implementations and whether or not …

Hcc Architecture - Hormonal Communications And Control Architecture, Paul R. Thompson

Theses

This thesis aims to provide a novel framework for a multiagent system implementation. The major feature of the proposed architecture is the introduction of the biological concept of hormones. The hormones are passed via the communication network to convey limited global system state knowledge. The agents' response to a hormone is interpreted depending on its own local agent state. The primary focus of this thesis is the development of the particulars of the architecture. Prior work of multiagent systems research is reviewed and studied for contributions. Biological studies of hormones are employed to draw out interaction rules and analyze control …

Mainstream Media Vs. Alternative Media : An Analysis, Daidre Moberg

Undergraduate Theses and Senior Projects

No abstract provided.

Mystery, Wonder, And Awe : The True Nature Of Science, Katie E. Rau

Undergraduate Theses and Senior Projects

No abstract provided.

Laser Vaporization Synthesis Of Single Wall Carbon Nanotubes, Jeffrey M. Elich

Theses

The effects of five experimental parameters in pulsed laser vaporization (PLV) synthesis of single wall carbon nanotubes (SWNTs) were examined. Parameters investigated include the laser beam raster pattern, reactor chamber temperature, graphite particle size in the target, reactor chamber configuration, and incident laser beam power density. The type and quality of resultant SWNTs synthesized were strongly influenced by altering these experimental conditions. This information can then be utilized to allow the experimentalist to exhibit a considerable degree of control over the physical and chemical properties of the as-produced SWNT materials. Characterization of the SWNT products was achieved using a combination …

Experimental Study Of Flow Patterns, Heat Transfer, Pressure Drop And Gravitational Orientation During Flow Boiling In Minichannels, Prabhu Balasubramanian

Theses

Microchannels and Minichannels are being used in electronic cooling, fuel cells, automotive heat exchangers, micro refrigeration systems. They are also being considered for high heat flux applications under microgravity environment in space missions. Research laboratories and industries throughout the world are trying to explore and tap the potential uses of these small diameter channels in various products and applications. Before stepping in to any of the product design phase, fundamental issues related to their performance have to be studied and resolved. This thesis work focuses on resolving some of these fundamental issues related to flow boiling in small diameter channels …

Feasibility Analysis Of Correlation Based Prefetching Using Digital Signal Processing, David L. Morse

Theses

As the gap between processor performance and memory performance continues to broaden with time, techniques to hide memory latency such as correlation based prefetching become exceedingly important. When a memory reference issued by the processor misses the level one cache, the request propagates down the memory hierarchy until it finally finds the requested datum. With each layer traversed, the latency grows exponentially. Prefetching is a technique used to hide this latency by attempting to predict which memory references will be requested in the near future, and then load them into cache before they are needed. This work investigates the use …

Evaluation Of The Playstation 2 As A Cluster Computing Node, Christopher R. Nigro

Theses

Cluster computing is currently a popular, cost-effective solution to the increasing computational demands of many applications in scientific computing and image processing. A cluster computer is comprised of several networked computers known as nodes. Since the goal of cluster computing is to provide a cost-effective means to processing computationally demanding applications, nodes that can be obtained at a low price with minimal performance tradeoff are always attractive. Presently, the most common cluster computers are comprised of networks of workstations constructed from commodity components. Recent trends have shown that computers being developed and deployed for purposes other than traditional personal computers …

Data Hiding In Images Based On Fractal Modulation And Diversity Combining, Sarat B. Atluri

Theses

The current work provides a new data-embedding infrastructure based on fractal modulation. The embedding problem is tackled from a communications point of view. The data to be embedded becomes the signal to be transmitted through a watermark channel. The channel could be the image itself or some manipulation of the image. The image self noise and noise due to attacks are the two sources of noise in this paradigm. At the receiver, the image self noise has to be suppressed, while noise due to the attacks may sometimes be predicted and inverted. The concepts of fractal modulation and deterministic self-similar …

Forecasting Hospital Bed Availability Using Computer Simulation And Neural Networks, Matthew J. Daniels

Theses

The success of hospitals in treating patients and staying in business relies on their efficient use of resources. In particular, the utilization of hospital beds is a critical concern, since over-crowding will result in delays or transfers of patients, and under-utilization will result in lost opportunity to treat patients and generate profit. To this end, hospital decision makers must have reliable forecasts of patient demand and bed availability. The objective of this thesis was to create a general method to forecast the availability of hospital beds in the short term, up to 2 days into the future. Specifically, this thesis …

Tangerine Sours, Gisèle N. Couturier

Theses

My thesis work will explore the use of the ceramic object as metaphor for the self. Due to my strong background and interest in science and mathematics, I have a tendency to process my surroundings through logical order and pattern. I am continuously searching for this order and trying to classify and organize data so that it makes sense to me. Finding this order within chaos, particularly in the natural world, is fascinating. My intention is to reference these biological elements in a form that has a clear delineation between interior and exterior. The dialogue between the two is where …

Enhanced Closed Loop Performance Using Non-Dimensional Analysis, Michael H. Wilson

Theses

This paper investigates the benefits of using non-dimension analysis to develop a control law for a flexible electro-mechanical system. The system that is analyzed consists of a DC motor connected to a load inertia through a set of gears. A state space system model is derived using LaGrange's equation and then non-dimensionalized using a linear transformation. The resulting system model reveals the system character more clearly through the resulting dimensionless parameters. The parameters highlight the interaction between system properties and motor constants and demonstrate the benefits of a concurrent mechatronics design process. Open-loop behavior is analyzed and an optimal value …

Color Quality - A Visual Comparison Between Iq Colour And Icc Based Color Management, Anirban Dutta

Theses

Color management has become central to achieving greater color quality and consistency and has become an integral part of a printing workflow. The contemporary printer is faced with the challenge of achieving high print and color quality in conjunction with low production cost to remain competitive. This thesis focuses on the subject of comparing the color quality obtained by implementing the IQ colour profiling system with respect to ICC profiling. The basis of this study is that the ultimate judge for color quality in the Graphic Arts industry is the print buyer and color quality should really be a function …

An Analysis Of The Consistency Of Brand Color Reproduction In Print Packaging And Magazine Advertising, Seunga Kang Ha

Theses

Brand color is one way to represent the identity of the corporation and for the company to advertise itself. The purpose of brand color is to make customers perceive the color, recognize the brand, and ultimately buy products manufactured by the corporation. However, it is not easy to produce the same color through different print media applications because of different processes of color reproduction technology. In the print industry, corporations have controlled brand color tolerance to insure its consistency. However, there is some question as to how the print industry actually performs in maintaining this tolerance through reproduction. The goal …

Dynamically Loaded Self-Aligning Journal Bearings: A Mobility Method Approach, Nathan Mayer

Theses

Journal bearings are a fundamental component in many pieces of machinery. A properly designed bearing is capable of supporting large loads in rotating systems with minimal frictional energy losses and virtually no wear even after years of services. These benefits make an understanding of dynamic behavior of these devices very valuable. In applications where journal bearings are subject to misalignment (conditions where the journal and sleeve axes are not parallel), it has long been understood that bearing performance can be compromised. To eliminate this problem, self-aligning bearings have been designed. The sleeves of these bearings are capable of moving freely …

A Convex Optimization Approach To The Design Of Multiobjective Discrete Time Systems, Anirudh Oberoi

Theses

One of the most important contributions of robust control theory has been the devel opment of a new framework for the design and analysis of feedback systems satisfying mixed time-frequency specifications. This framework is given by the Linear Matrix Inequality (LMI) approach where design and analysis problems are posed as convex optimization problems subject to affine matrix constraints. Most of the focus in this area has been on continuous-time systems design with very few results for discretetime systems. One of the main contributions of this work is the development and implementation of a MATLAB toolbox for discrete-time controller design using …

Visual Design Systems For Music Education, Andrew D. Baker

Theses

Not Included

Melting Multimedia: A Study Of Methods And Processes For Developing Small-Scale Dynamic Multimedia Systems That Can Be Easily Updated By The Client, Paul Martin

Theses

This report reviews the process and practices involved in creating a multimedia proj ect with an efficient work flow and content that can be edited by the client using a Web browser. Construction methods are reviewed and explained.

A Physics-Based Model Of Sic-Based Mesfets, Sankha Mukherjee

Theses

Silicon Carbide (SiC) has been investigated as an alternative material to Silicon (Si) for enhancing the power-handling capability of semiconductor devices for simultaneous high-temperature and high frequency applications. Its high thermal conductivity, high bandgap, low permittivity, high saturation velocity, moderate mobility, material hardness and chemical inertness make it a prime candidate for power electronics, heat and light sensors, and MEMS applications. The MESFET is the most viable power transistor based on SiC. The performance of SiC MESFETs is limited by trapping and thermal effects. A physics-based analytical model of the SiC MESFET incorporating trapping and thermal effects is reported. The …

A Physics-Based Analytical Model Of An Algan/Gan High Electron Mobility Transistor, Jonathan Sippel

Theses

Popular semiconductors currently being used for RF applications include GaAs and InP. The operating frequencies for HEMTs built with these semiconductors covers the range from 800 MHz to 100 GHz. Although high-speed operation is attainable using GaAs or InP, product performance is limited when considering high-power applications, where a high breakdown field and thermal conductivity is needed. Proposed about fifteen years ago as a solution to this problem, GaN has emerged as a viable candidate to challenge, and perhaps overtake, GaAs and InP as the dominant semiconductor in RF products, particularly power amplifiers. This is due to its high breakdown …

Vibration Of Hollow Cylindrical Shells With Partial Constrained Layer Damping, Nathan E. Smith

Theses

A theoretical analysis is presented for determining the natural frequencies and damping factors for isotropic circular cylindrical shell type structures. Equations of motion for a cylindrical shell and a three-layer cylindrical shell fully and partially treated, with a viscoelastic core, are derived from equilibrium. The assumed mode method or Galerkin method are used to find the equivalent mass and stiffness matrices from which the natural frequencies can then be obtained. The effects on the natural frequency and damping factor due to various viscoelastic core thicknesses, viscoelastic shear moduli, constraining layer thickness, constraining layer Young's moduli, and viscoelastic coverage length are …

Multi-Timeline Randomized Story Based Web Animation, Jonathan Fahnestock

Theses

Multi-Timeline Randomized Story Based Web Animation is the investigation of the use of randomness as a creative element and production tool for animations produced for the internet using Macromedia FlashTM. It discusses the process of utilizing Actionscript to create animations more efficiently, production techniques for animating with Flash, writing for randomized animations, directing voice talent, optimization for web output, and advantages and limitations of the application. The application discussed, titled "Random Life," is an animation which incorporates randomness while remaining coherent by adhering to a traditional story line format.

Modeling Of Probe-And-Drogue Part Of An In-Flight Refueling System, Jie Yan

Theses

In this work, a finite element model of an in-flight aircraft refueling system is developed. The model is a first attempt to describe the dynamics of a probe-and-drogue refueling system commonly used by Navy aircraft. The purpose of this work is to develop a model of the drogue system to be able to study control and sensor system requirements for an autonomous refueling system. This work is intended as a first introduction to an automated in-flight refueling system with special concentration on the modeling of a probe-and-drogue in-flight refueling system for aircrafts. An understanding of what is an in-flight refueling …

A Use-Case Model For A Knowledge Management System To Facilitate Disaster Relief Operations, Eileen Eudy

CCAC Theses and Dissertations

There are numerous disaster relief agencies poised to respond to disasters; however, coordinating the activities of these diverse and dispersed entities and capitalizing on their knowledge assets can be a challenge. All of these agencies are dedicated to serving survivors of disasters, but they at times lack the coordination necessary to respond efficiently. The Virginia Voluntary Organizations Active in Disaster (VOAD) is an umbrella organization of existing agencies dedicated to working closely with other organizations to improve service and minimize duplication during disaster operations. To better cope with disasters, the Virginia VOAD needs to develop knowledge management strategies to coordinate …

Why Am I My Brother's Keeper?, Donald H. Regan

Book Chapters

I want to cast doubt on a proposition which many people would regard as the first axiom of moral theory. Joseph Raz has stated the proposition thus: 'Morality is ... concerned with the advancement of the well-being of individuals.' Actually, Raz includes a qualifier-the full quote says that morality 'is thought to be concerned with' advancing the well-being of individuals. But the whole tenor of his ensuing discussion suggests that Raz generally shares this view of what morality is about.

As I say, I want to cast doubt on this axiom, but I shall not take issue with any particular …