Engineering Commons^™

Algorithms For The Njit Turbonet Parallel Computer, Nitin J. Lad

Theses

Element selection for arrays, array merging, and sorting are very frequent operations in many of today's important applications. These operations are of interest to scientific, as well as other applications where high-speed database search, merge, and sort operations are necessary and frequent. Therefore, their efficient implementation on parallel computers should be a worthwhile objective. Parallel algorithms are presented in this thesis for the implementation of these operations on the NET TurboNet system, an in-house built experimental parallel computer with TMS320C40 Digital Signal Processors interconnected in a 3-D hypercube structure. The first algorithm considered is selection. It involves finding the k-th …

Reverse Osmosis As A Pretreatment Of Ion Exchange Equipment At Pse & G'S Hudson Generation Station, Steven Leon

Theses

Public Service Electric and Gas Company's Hudson Generating Station has historically had problems providing sufficient high quality water for its two once through, supercritical design boilers. The station requires over 60 million gallons annually to compensate for system losses.

The stations' ion exchange demineralizers proved to be costly to operate and overall inefficient in performance. Drawbacks include: short service cycles, periodic contamination of storage tanks due to premature breakthrough, prohibitively high chemical regenerant costs, excessive labor requirements, frequent resin replacement, and overall unreliable plant operations.

A reverse osmosis unit was installed as a pretreatment to the demineralizers to offset these …

Performance Evaluation Of Specialized Hardware For Fast Global Operations On Distributed Memory Multicomputers, Rajesh Madukkarumukumana Sankaran

Dissertations and Theses

Workstation cluster multicomputers are increasingly being applied for solving scientific problems that require massive computing power. Parallel Virtual Machine (PVM) is a popular message-passing model used to program these clusters. One of the major performance limiting factors for cluster multicomputers is their inefficiency in performing parallel program operations involving collective communications. These operations include synchronization, global reduction, broadcast/multicast operations and orderly access to shared global variables. Hall has demonstrated that a .secondary network with wide tree topology and centralized coordination processors (COP) could improve the performance of global operations on a variety of distributed architectures [Hall94a]. My hypothesis was that …

Diagnostics And Analysis Of Incident And Vapor Shield Plasmas In Pladis I, An Iter Relevant Tokamak Disruption Simulator, Joseph Thomas Bradley Iii

Electrical and Computer Engineering ETDs

The International Thermonuclear Experimental Reactor program (ITER) is a world wide collaboration to design and build the first new large scale tokamak fusion reactor of the 21st century. Under certain operating conditions the highly energetic plasma contained within a tokamak can become unstable and result in a loss of magnetic confinement, allowing the plasma to strike the interior of the vacuum chamber and cause damage. This event is known as a disruption. Plasma Facing Component (PFC) materials protect the interior of the tokamak from damage in the event of a disruption. Complex scaling laws have been used to estimate the …

Performance Analysis Of A Banyan Based Atm Switching Fabric With Packet Priority, Zhaohui Yan

Dissertations and Theses

Since the emergence of the Asynchronous Transfer Mode ( A TM ) concept, various switching architectures have been proposed. The multistage interconnection networks have been proposed for the switching architecture under the A TM environment. In this thesis, we propose a new model for the performance analysis of an A TM switching fabric based on single-buffered Banyan network. In this model, we use a three-state, i.e., "empty", "new" and "blocked" Markov chain model to describe the behavior of the buffer within a switching element. In addition to traditional statistical analysis including throughput and delay, we also examine the delay variation. …

Shear Strength And Fatigue Crack Propagation In Concrete By Energy Method, Wei Wang

Dissertations

The limit analysis methods have been commonly used to predict the ultimate flexure strength of reinforced concrete members over 50 years. However, current design formulas for shear in structural concrete are mostly empirical. In part one of this dissertation, attempts are made to apply the theory of plasticity to predict the shear strengths of reinforced concrete structures.

The modified Coulomb-Mohr failure criterion is used as the constitutive law of concrete, and the plastic flow is assumed to be associated with this failure criterion. A generalized formulation for energy dissipation in accordance with the failure criterion and associated flow rule is …

A Nondestructive Method For The Determination Of Fracture Energy In Concrete Structures, Been-Jyh Yu

Dissertations

It is generally believed that linear elastic fracture mechanics concepts can not be employed in determining fracture parameters in concrete, and therefore most of the current research effort has focused on applying the principles in yielding fracture mechanics. Despite all these efforts, comparison of results reported by many investigators indicate wide variations in fracture toughness values even for essentially similar materials. The main source of discrepancy in the observed results is the existence of a large process zone at the crack tip. Hence, the amount of energy consumed in advancing the crack will depend on the size of the process …

The Evolution And Testing Of An Aerovalve Pulsejet Engine, Gregory V. Meholic

Master's Theses - Daytona Beach

The goal of this project was to develop and test a self-aspirating aerovalve pulsejet and measure its operating characteristics. An investigation of pulsejets developed by previous experimenters revealed design trends associated with the engine geometry. These trends were followed in the development of an aerovalve pulsejet engine entitled the Astra. The engine employed variable fuel injection methods, ignition location and exhaust pipe length to show that certain combinations of geometry relations and fuel injection methods were more conducive to pulse combustion. Even though the engine pulsed with forced inlet air, the Astra did not self-aspirate as did the engines …

A Computer-Aided Software Engineering (Case) Approach To Business Process Reengineering (Bpr), Faiza I. Khan

Master's Theses - Daytona Beach

This thesis addresses the problem of lack of procedures by which managers can identify business processes that would benefit from reengineering and which could be used to guide the BPR activity to its successful conclusion. The purpose of this study is to analyze various Software Engineering (SE) principles to determine whether they could be used to support Business Process Reengineering (BPR) activities either directly or with some modification, and if so, whether available Computer-Aided Software Engineering (CASE) tools might be applied to BPR in support of managers who wish to implement it. The principles of SE and BPR are discussed …

An Experimental Investigation Of Wall Cooling Effects On Hypersonic Boundary Layer Stability In A Quiet Wind Tunnel, Alan E. Blanchard

Mechanical & Aerospace Engineering Theses & Dissertations

One of the primary reasons for developing quiet tunnels is for the investigation of high-speed boundary-layer stability and transition phenomena without the transition-promoting effects of acoustic radiation from tunnel walls. In this experiment, a flared-cone model under adiabatic- and cooled-wall conditions was placed in a calibrated, 'quiet' Mach 6 flow and the stability of the boundary layer was investigated using a prototype constant-voltage anemometer. The results were compared with linear-stability theory predictions and good agreement was found in the prediction of second-mode frequencies and growth. In addition, the same 'N=10' criterion used to predict boundary-layer transition in subsonic, transonic, and …

Buckling Analysis And Optimum Design Of Multidirectionally Stiffened Composite Curved Panel, Navin R. R. Jaunky

Mechanical & Aerospace Engineering Theses & Dissertations

Continuous filament grid-stiffened structure is a stiffening concept that combines structural efficiency and damage tolerance. However, buckle resistant design optimization of such structures using a finite element method is expensive and time consuming due to the number of design parameters that can be varied. An analytical optimization procedure which is simple, efficient and supports the preliminary design of grid-stiffened structures for application to combined loading cases is needed.

An analytical model for a general grid-stiffened curved panel is developed using an improved smeared theory with a first-order, shear-deformation theory to account for transverse shear flexibilities and local skin-stiffener interaction effects. …

System Dynamic Modeling Of Activity And Flow Relationships In Plant Layout Problems, Gary Allen Weaver

Engineering Management & Systems Engineering Theses & Dissertations

The problem of determining an optimal plant layout involves the distribution of machinery, service areas, and storage spaces. The solution is usually determined for a specific period of time and static in nature. Planning for the plant layout is normally performed at the onset of new construction, or major refurbishment of an existing facility. In addition, plant layouts are renewed when a significant productivity decrease is experienced over long periods of time and linked to material flow problems, and when an expanding company plans for major capital expenditures in equipment and space. Due to the dynamic nature of business the …

Assessment Of High-Order Serendipity And Lagrangian Quadrilateral Membrane Elements, Timothy Scott Davis

Mechanical & Aerospace Engineering Theses & Dissertations

The development and implementation of high-order Lagrangian and serendipity quadrilateral elements including a biquartic Lagrangian element, a 16-node serendipity element, and a 17-node serendipity element are presented and assessed. This assessment includes an evaluation of the patch test, an element eigenvalue test to detect any zero-energy modes, and selected plane stress problems. The effects of using both full and reduced numerical integration procedures and optimum locations for stress recovery are discussed. All elements evaluated represent the three rigid-body modes without inducing strains, exhibit geometric isotropy, and pass the membrane patch test. The most promising high-order quadrilateral element proved to be …

Atomic Broadcast In Heterogeneous Distributed Systems, Osman Zeineldine

Computer Science Theses & Dissertations

Communication services have long been recognized as possessing a dominant effect on both performance and robustness of distributed systems. Distributed applications rely on a multitude of protocols for the support of these services. Of crucial importance are multicast protocols. Reliable multicast protocols enhance the efficiency and robustness of distributed systems. Numerous reliable multicast protocols have been proposed, each differing in the set of assumptions adopted, especially for the communication network. These assumptions make each protocol suitable for a specific environment. The presence of different distributed applications that run on different LANs and single distributed applications that span different LANs mandate …

Experimental Investigation Of The Inlet Deflector Configuration Variation In The Flow Field At Mach 1.9, Kyu C. Hwang

Mechanical & Aerospace Engineering Theses & Dissertations

In recent years, active research has been conducted to study the technological feasibility of supersonic laminar flow control on the wing of the High Speed Civil Transport (HSCT). For this study, the F-16XL has been chosen due to its highly swept crank wing planform that closely resembles the HSCT configurations. During flights, it is discovered that the shock wave generated from the aircraft inlet introduces disturbances on the wing where the data acquisition is conducted. The flow field about a supersonic inlet is characterized by a complex three-dimensional pattern of shock waves generated by the geometrical configuration of a deflector …

Text Independent Speaker Verification Using Binary-Pair Partitioned Neural Networks, Claude A. Norton Iii

Electrical & Computer Engineering Theses & Dissertations

A method is presented for the application of binary-pair partitioned neural networks to the task of speaker verification. This technique is based on a previously developed neural network classifier for speaker identification.

The main focus of this research was the development and testing of the algorithms necessary to extend the binary-pair partitioning approach from speaker identification to speaker verification. The method is based on the development of a user profile which is obtained from discriminative data provided by the binary-pair partitioned neural networks.

Experimental results are provided which demonstrate the viability of this approach, using the TIMIT speech corpus for …

Finite Element Formulation Of A Three-Node Spatially Curved And Twisted Beam, Umesh Vishnu Padhye

Mechanical & Aerospace Engineering Theses & Dissertations

A three-node curved and twisted beam element is developed for linear analysis of structures modeled with curved and pre-twisted beams. A set of governing equations consisting of kinematic relations, constitutive relations, and equilibrium equations is derived. The beam element has three rotational and three displacement degrees of freedom at each node. The differential equations of kinematics are solved exactly for linearly varying longitudinal strains, constant transverse shear strains, linearly varying twist, and quadratically varying curvature changes to obtain the description of rotation and displacement modes. These rotation and displacement modes are then used as the basis functions for development of …

Job Satisfaction And Dissatisfaction Factors Of Airport Security Screeners: National Survey Results, Francis X. Goeddeke Jr.

Master's Theses - Daytona Beach

The purpose of this study is to accurately and reliably determine what factors are most important to airport security screeners that effect job satisfaction and excessive employee turnover. Using survey items generating in a previous study, job satisfaction and job dissatisfaction survey scales for this population were developed and validated. A modified version of the Rensis Likert Scale of Organizational Climate was also developed. These surveys, including a demographic questionnaire, were administered to a large nationwide sample of airport security screeners. The results were analyzed using chi-square contingency tables, one-way analysis of variance tests, and the Fisher post-hoc procedure. Post-hoc …

Full Envelope Control Of Nonlinear Plants With Parameter Uncertainty By Fuzzy Controller Scheduling, Thomas J. Kobylarz

Theses and Dissertations

A full envelope controller synthesis technique is developed for multiple-input single-output (MISO) nonlinear systems with structured parameter uncertainty. The technique maximizes the controller's valid region of operation, while guaranteeing pre-specified transient performance. The resulting controller does not require on-line adaptation, estimation, prediction or model identification. Fuzzy Logic (FL) is used to smoothly schedule independently designed point controllers over the operational envelope and parameter space of the system's model. These point controllers are synthesized using techniques chosen by the designer, thus allowing an unprecedented amount of design freedom. By using established control theory for the point controllers, the resulting nonlinear dynamic …

An Empirical Investigation Of The Integrated Weapon System Management Concept Of Seamless Processes, Timothy H. Surabian

Theses and Dissertations

This research investigated the way four Air Force Materiel Command (AFMC) single manager organizations operationalized the Integrated Weapon System Management (IWSM) concept of "seamless processes." In this thesis, the IWSM concept of "seamless processes" refers to the degree of integration between acquisition and sustainment organizations. Four SPO organizations were involved in six case studies. This research focused on the way "seamless processes" affect the shifting of the organizational "center of gravity" within or between single manager organizations. An interview questionnaire was administered to 13 Product Center managers and 6 Logistics Center managers. The interview questions focused on IWSM in general, …

A Model For Forecasting Pollution Prevention Life Cycle Costs For Air Force Major Weapon Systems, Mark E. Garner, Jennifer S. Kirchoffer

Theses and Dissertations

This research effort developed a modification to the HAZMAT program so that the program could provide the user with the capability to generate an estimate during the concept exploration and design phases for the total costs associated with hazardous materials usage in a major weapon system. Using the HAZMAT database, a spreadsheet was developed which projects a cost for a weapon system based on its total surface area and the number of aircraft to be produced by performing an analogy with a similar weapon system. The modification uses algorithm which are based on the hazardous material substances rather than processes …

Optical Characterization Of Indium Arsenide Antimonide Semiconductors Grown By Molecular Beam Epitaxy, Michael A. Marciniak

Theses and Dissertations

The material parameters and crystalline quality of undoped, MBE-grown InAs_1-xSb_x nearly lattice-matched to (100) GaSb (-0.617% ≤ Δ a-a ≤ +0.708%) similar to material used for mid-infrared semiconductor lasers were determined by optical characterization. Absorption measurements at temperatures between 6-295 K determined the energy gap and wavelength-dependent absorption coefficient for each sample. The compositional dependence of the energy gap was anomalous when compared to previously reported data, suggesting phase separation existed in the material. The samples were also studied by temperature- and excitation-dependent photoluminescence (PL), which, for the majority of cases, showed only a single band-edge peak, …

Non-Imaging Infrared Spectral Target Detection, Matthew R. Whiteley

Theses and Dissertations

Automatic detection of time-critical mobile targets using spectral-only infrared radiance data is explored. A quantification of the probability of detection, false alarm rate, and total error rate associated with this detection process is provided. A set of classification features is developed for the spectral data, and these features are utilized in a Bayesian classifier singly and in combination to provide target detection. The results of this processing are presented and sensitivity of the class separability to target set, target configuration, diurnal variations, mean contrast, and ambient temperature estimation errors is explored. This work introduces the concept of atmospheric normalization of …

Optimal Inputs For System Identification, James M. Brown Ii

Theses and Dissertations

The derivation of the power spectral density of the optimal input for system identification is addressed in this research. Optimality is defined in information theoretic terms, with entropy quantifying the parameter information content of the input and output measurement sequences pertaining to a discrete time plant. The maximization of entropy is performed in the context of three different scenarios. First, the case in which the average output power of the plant is constrained is considered. Second, input average power is constrained. Finally, the optimization is carried out unconstrained, but with penalties applied to both the input and output powers. Although …

An Evaluation Of Cost Metrics Used Within Aeronautical Systems Center, Kevin M. Byrne

Theses and Dissertations

Aeronautical Systems Center (ASC) system program offices rely on cost metrics to acquire information on program effectiveness and organizational improvement. This study was an attempt to determine the effectiveness of ASC’s cost metrics. The effectiveness of the metrics were determined by the desirability of the behaviors which are exhibited when individuals utilize the specific metrics. Using an expert panel to evaluate the metrics, data was collected using the Group Research Laboratory for Logistics located in Armstrong Laboratory at Wright Patterson AFB, OH. Metric diagnostic charts were utilized to arrange the data into a format which would provide effectiveness information. The …

Aggregating Organizational Performance Metrics Using The Analytic Hierarchy Process, Bret L. Indermill

Theses and Dissertations

Measurement provides factual information which is necessary for effective control of business processes. Implementing a Total Quality Management (TQM) philosophy is a common process in many organizations today. The United States Air Force is using the Malcolm Baldrige National Quality Award criteria to measure organizational performance in implementing the Quality Air Force (QAF) initiative. Unfortunately, the Baldrige-based unit self-assessment (USA) process is an inconsistent measure due to its subjectivity, and is also time consuming to use. This study determined that a new USA method based on the analytic hierarchy process (AHP) was not a significant improvement over the existing QAF-USA …

An Investigation Into Aircraft Availability, Michael S. Kapitzke

Theses and Dissertations

The Air Force currently uses an expected value model in the Aircraft Availability Model (AAM) to calculate aircraft availability. However, even with the application of Lean Logistics, the failure-demand rate and the depot repair time are not fixed and the mean value is still used in the model. This research looks at the effect of the magnitude of the variance of the distributions of failure-demand rate and depot repair time. Also, this research evaluates the effect of variable mean failure-demand rates on the variability of aircraft availability. A simulation model was developed which applied the variable failure-demand rates and depot …

Assisting Defense Conversion Technology Transfer Efforts. A Case Study Of Ohio's Miami Valley, Marissa C. Salvador

Theses and Dissertations

Major changes in the geopolitical environment and the social and economic needs of the United States have resulted in resources being shifted away from national defense. Although the expected decrease in defense spending should not be harmful in macroeconomic terms, it can be devastating locally. To mitigate the effects of the drawdown, individual states and local communities must search for ways to bolster their local economies. One avenue that can be pursued to enhance future economic growth is the transferring of technologies to the commercial sector. Intermediary organizations have emerged to facilitate the process of technology transfer by serving as …

The Process Of Technology Transfer: A Case Study Of The National Aero-Space Plane Program, Brett T. Smith

Theses and Dissertations

Due to reduced funding levels and increased pressure towards cooperation with industry, government research and development (R&D) organizations are becoming increasingly involved in the transfer of technology to the commercial sector. However, the process of technology transfer is complex, and transfer activities are being applied inconsistently across the Department of Defense. This research explores the approaches, processes and mechanisms to accomplish technology transfer. A comprehensive literature review documents many of the transfer concepts that have been proposed or are currently in use. A detailed case study then examines the technology transfer efforts of an advanced government research organization: the National …

A Comparison Of Consistent Versus Inconsistent Scheduling Rules In A Flow Shop Environment, Nicola Gismondi

Theses and Dissertations

A consistent scheduling rule is one which will ensure a job's priority (relative to all other job's) will remain constant as it moves from queue to queue in a production system. Previous research concerning flow shop priority scheduling rules focused on comparison of either consistent or inconsistent rules. Conversely, this study sought to provide additional insight by comprising consistent and inconsistent rules in a flow shop environment The Air Force uses both types of rules in maintenance and logistics scheduling. Time and money can be saved if the scheduling managers can better understand the effect of consistency on a system. …