Digital Commons Network^™

Performance Evaluation Of Spread Spectrum System With Cochannel Interference Through A Nonlinear Channel, Yong H. Kim

Dissertations

This thesis deals with the problem of more than one subscriber transmitting data signals through a common satellite repeater using code division multiplexing to separate the signals. We are concerned with the problem of amplifying two DS spread spectrum signals, both QPSK or BPSK modulated, in a common device in which limiting occurs. One signal is considered the signal we desire to receive, and the other, having the same nominal carrier frequency with a small random offset, is considered to be a cochannel interferer. The case of a cochannel interferer on the uplink and downlink in QPSK signalling and BPSK …

Process Technology And Characterization For Field Emission Devices, Jong Min Kim

Dissertations

Vacuum microelectronics is a new research field which applies semiconductor process technology to the fabrication of micron-dimensioned electron devices. Vacuum microelectronics is made possible by advances in microstructures and nanofabrication technology. Vacuum microelectronic devices are further characterized by a wide operating temperature range, nuclear radiation immunity, higher emission current density potential, and lower power consumption than that of thermionic emitters. The low mass of the electron provides a higher carrier mobility than GaAs or any solid state device. These features offer the potentials for wide variety of applications.

In this dissertation. electron field emission structures applicable to a variety of …

Investigation Of Epitaxial Lift-Off Gaas And Langmuir-Blodgett Films For Optoelectronic Device Applications, Divyang M. Shah

Dissertations

Epitaxial lift-off (ELO), a technique of removing an epitaxially grown GaAs layer from its growth substrate by selective etching of an AlAs sacrificial layer, is described for field-effect transistor fabrication independent of the GaAs growth substrate. Metal Semiconductor Field-Effect Transistors (MESFETs) and High Electron Mobility Transistors (HEMTs) fabricated on silicon and sapphire substrates using ELO are investigated. A 0.1 μm gate length depletion mode MESFET made on silicon exhibited a unity current gain frequency f_t = 34 GHz. Excellent device isolation with subpicoampere leakage currents is obtained. A high input impedance amplifier has been implemented on silicon substrate using …

Modeling And Performance Of Token Bus Lan With Petri Nets, Zhenggang Pan

Theses

A token bus local area network (LAN) is analyzed by Generalized Stochastic Petri Nets (GSPN). The GSPN models of both a single station and LAN for four types of service schemes are obtained and their liveness property is proved. The network performance parameters comprise throughput and delay. The performance analysis for both symmetric and asymmetric single-service systems is conducted for varying load. In order to analyze a token bus LAN with a large number of stations, an approximation method is developed to resolve the .state space explosion problem. A token bus LAN with twenty-one stations is used to show the …

Comparing Techniques Of Mapping Pyramid Algorithms Onto The Hypercube : A Case Study For The Connection Machine, Muhammad Ali Siddiqui

Theses

The pyramid structure is most widely used for low-level and intermediate-level image processing and computer vision because of its efficient support of both local and global operations. However, the cost of pyramid computers (PC) may be very high. They also do not support the efficient implementation of the majority of the scientific algorithms. In contrast, the hypercube network has widely been used in the field of parallel processing because it offers a high degree of fault tolerance, a small diameter and rich interconnection structure that permits fast communication at a reasonable cost. Thus, several algorithms have been developed for the …

A New Method To Optimize The Satellite Broadcasting Schedules Using The Mean Field Annealing Of A Neural Network, Youyi Yu

Theses

This thesis reports a new method for optimizing satellite broadcasting schedules based on the Hopfield neural model in combination with the mean field annealing theory. A clamping technique is used with an associative matrix, thus reducing the dimensions of the solution space. A formula for estimating the critical temperature for the mean field annealing procedure is derived, hence enabling the updating of the mean field theory equations to be more economical. Several factors on the numerical implementation of the mean field equations using a straightforward iteration method that may cause divergence are discussed; methods to avoid this kind of divergence …

An Embedded Controller-Based Fiber Optic Sensor For Use In Fresh Concrete, Zhaowu Zhang

Theses

The principle of refraction and reflection of light in optical fibers is applied to detection of air bubbles in a previous thesis. In the earlier work, a microcomputer was employed in acquisition and processing of air bubble data. In the present thesis, an embedded controller system is interfaced and programmed in order to replace the microcomputer. In this way, the system can be more easily integrated into field construction operations. Reflected light intensity signals are detected and analyzed by a microcontroller. The entrained percentage of air in concrete is displayed immediately. The signal can be transferred through a UART (Universal …

Processor Allocation Strategies For Modified Hypercubes, Nagasimha G. Haravu

Theses

Parallel processing has been widely accepted to be the future in high speed computing. Among the various parallel architectures proposed/implemented, the hypercube has shown a lot of promise because of its poweful properties, like regular topology, fault tolerance, low diameter, simple routing, and ability to efficiently emulate other architectures. The major drawback of the hypercube network is that it can not be expanded in practice because the number of communication ports for each processor grows as the logarithm of the total number of processors in the system. Therefore, once a hypercube supercomputer of a certain dimensionality has been built, any …

Design Of A Material Handling System For The Automatic Assembly Of A Shower Head, Irshad Meherally

Theses

The design of a Material Handling System for the Shower Head assembly is proposed. The working principle of complete automation and individual workstation is presented using "I-DEAS" software. Alternative equipments and their usage in the automation of the assembly is also proposed. Custom made fixtures, workcarriers, orienters, magazines, part feeders are designed for the assembly. Analysis of design for assembly in terms of cost and efficiency is performed by generating a Coding System Technique.

Clustering Algorithm For Local Area Network Design In A Cim Environment, A. C. Manjunath

Theses

Communication systems have come to be regarded as being one of the most important aspects in manufacturing enterprises in recent years. It continues to offer enormous potential for improving the efficiency of manufacturing enterprises through Computer Integrated Manufacturing (CIM). It is true however that this potential cannot be realized by developments on the communications front alone. Strategic and economic considerations in installing a communications system in a manufacturing environment is of vital significance.

This thesis, at the outset attempts to bring out some of the issues in the area of communications (research), specifically in relation to CIM. A perception of …

A Computer Implementation Of A Multi-Neuron Expandable Network, Mary Ellen Ellen Aleksza

Theses

The primary goal of this thesis is to develop a small, expandable neural network that oscillates when presented with an appropriate stimulus. This model will be used in the future as a base to create larger networks. Future studies of these larger networks may be used in the simulation of neuronal activity such biological oscillators.

This thesis encompasses a study of neuron activity, neural networks, neuron models and biological oscillators. The focus of the thesis is the modification and expansion of a single neuron simulation into a simulation of an interconnected multi-neuron oscillatory network.

A single neuron model based on …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 8, Number 5, May 1992, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A six page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Acuta Enews May 1992, Vol. 21, No. 5

ACUTA Newsletters

In This Issue

Nominations for officers sought

President's column

AT&T opens development site

Northeast regional meeting

Review: 'Optical Fiber Communications' (2nd Edition), By Gerd Keiser, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

If first impressions are worth anything (and they usually are), I would have to admit that my first impression of the second edition of Gerd Keiser's now popular text Optical Fiber Communications was quite good. My compliments are hereby extended to the publisher for choosing a rather handsome cover and dust jacket. It stands in strong contrast to the text's first edition, which still ranks as probably the ugliest book I own, with color choices ranging from dull cream and "baby" blue to pale pink! I am now happy to say that this older version has been discretely·retired to the …

A Survey Of Electronic Environmental Controllers, Richard S. Gates, Douglas G. Overhults, Larry W. Turner

Biosystems and Agricultural Engineering Faculty Publications

Sixteen commercially available electronic environmental controllers were evaluated. The units were classified according to enclosure type, analog versus microprocessor based control, power supply, sensors, alarms, control relays and triac output, interval timers, outside temperature feedback, and retail price. An assessment of these controllers indicated several critical limitations in the application of this technology.

The use of integrated controllers for animal production has the potential for substantial improvements in production efficiencies. If the limitations observed in the present controller technology, as represented by this sample, are addressed, industry acceptance of the technology can be accelerated. A uniform standard to address this …

Identifying Quality Function Deployment's Variables, Outcomes, Their Relationships, And Guidelines For Practitioners In The American Automotive Industry, Geoffrey Paul Gilmore

Dissertations and Theses

American industry is about nine to 12 years behind in utilizing a new product development and introduction process known as Quality Function Deployment (Q.F.D.). American industry must learn to compete internationally; the American automotive industry alone directly and indirectly employs millions of workers and has billions of dollars in annual sales and profits at stake.

With the cooperation of one American automotive company research has been conducted on Q.F.D. The research objectives were to identify: what variables affect Q.F.D., what are the outcomes from Q.F.D., what relationships exist between Q.F.D. variables and outcomes, and what guidelines may be offered to …

Computer Software Control Of A Three-Joint Model Robot, John W. Fierke

Opportunities for Undergraduate Research Experience Program (OURE)

The general scope of the computer program to control a three-joint model robot is presented. Several existing and potential sources of difficulty are also mentioned. For all specific explanations the reader is referred to the thesis papers of Richard Wainwright and Eric Stelzer. This presentation merely adheres to the description of the software to control the robot using the existing information contained in these two papers.

Microcomputer Control Of A Model Robot System, David N. Ilges

Opportunities for Undergraduate Research Experience Program (OURE)

The project involved creating an interface board that would allow an I.B.M.- AT computer to control a model robotic system already in existence. The I.B.M.- AT computer was then to be programmed in Pascal such that the model robotic system could perform various path movements and functions. The interface board involved taking various digital outputs from the computer and converting them to analog control signals or use them to turn devices off and on. The interface board also would collect inputs from the robotic system and convert these analog values back to digital words.

Behavior Of Composites For The Nasp Project, Robert B. Stone

Opportunities for Undergraduate Research Experience Program (OURE)

It is well known that ceramics are strong, highly heat resistant, refractory materials. Unfortunately, they are brittle and fail catastrophically. However, the strength as well as fracture toughness of ceramics can be greatly improved with the addition of continuous fibers, thus obtaining ceramic matrix composites (CMC). Normally the addition of aligned continuous fibers to a matrix degrades the transverse (the direction 90° to the fiber axes) properties while greatly improving the longitudinal properties. It has been shown that the addition of whiskers to a continuous fiber CMC will improve moduli and strength properties in both the transverse and longitudinal directions. …

Robotics Development And Design: Optical And Computer Controls, David E. Brown

Opportunities for Undergraduate Research Experience Program (OURE)

In industry today, the use of robotic systems is growing. They can be found in many diverse applications including washing dishes, assembling automobiles and carrying explosives. With such a wide range of applications, robotic systems are a very important division of engineering.

Designing such systems requires an interaction between different disciplines of engineering. In the work world, engineers are required to interrelate with other engineers of differing disciplines and backgrounds. This research was designed to implement this type of partnership and develop a project that required the knowledge of an electrical, a mechanical and a computer science engineer.

Using the …

Solution Of Divertor Magnetohydrodynamic Equilibria For The Study Of Alpha Particle Edge Transport In Fusion Plasmas, J. W. Schumer

Opportunities for Undergraduate Research Experience Program (OURE)

Removal of thermalized alpha particles from deuterium- tritium (D-T) fusion plasmas can be accomplished through the use of divertor magnetic fields if the magnetohydrodynamic (MHD) equilibria is well understood [1]. Modifying a MHD variational energy principle for poloidal flux surfaces described by �� = ��(ρ, θ) results in an inverse Fourier representation of the three-dimensional (3-D) equilibria solution. Application of the �� = ��(ρ, θ) flux profile allows transformation of the magnetic field into a non-singular coordinate system along the divertor separatrix [2] and therefore, analysis of different divertor schemes. Derivation of the coupled, non-linear differential equations follows [5] except …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 8, Number 4, April 1992, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Acuta Enews April 1992, Vol. 21, No. 4

ACUTA Newsletters

In This Issue

Call for Award nominations

President's column

Managing Telecom review

Creighton opens access, ends fraud

Membership Service Coordinator

San Francisco registration form

Santa Clara Magazine, Volume 34 Number 3, Spring 1992, Santa Clara University

Santa Clara Magazine

12 - EAST L.A. STORY Jesuit-run Dolores Mission Alternative School is a last chance for East L.A.'s troubled teen-agers, many of whom are members of violent Latino gangs. By Rene Romo '86

20 - ONE IS TOO MANY TWO ARE NOT ENOUGH A personal account of one woman's struggle with alcohol addiction. By Lisa Agrimonti '87

24 - UP CLOSE: WITOLD KRASSOWSKI After five years in the Polish Underground Army during WW II, the founder of SCU's Sociology Department came to America and discovered teaching. His 40-year commitment to students has never waivered. By Christine Spielberger '69

28 - WORKING …

Bulletin - Spring, 1992, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A twelve page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.

Effect Of Intruder Vertical Rate On Pilot Perception Of Separation On A Cockpit Traffic Display, Bryan H. Rooney

Master's Theses - Daytona Beach

The purpose of this study was to determine the effect of intruder vertical rate on pilots’ perception of aircraft separation as viewed on a cockpit traffic display. A group of 20 student pilots from Embry-Riddle Aeronautical University participated as subjects. SuperCard® software and a Macintosh II® personal computer were employed to generate the simulation of a cockpit display of traffic information. Each pilot monitored 84 scenarios in which they had to perceive how far away a single intruder would pass over or under their own aircraft. The pilots’ decision time, vertical and horizontal distance at decision time and percentage of …

A General Three Dimensional All Quadrilateral Surface Mesh Generation Algorithm, Roger Cass

Theses and Dissertations

Among the available all-quadrilateral mesh generation algorithms progressive-front offers the best quality and robustness. The paving algorithm is a progressive-front technique that generates a two dimensional mesh of all quadrilaterals on planar surfaces. The technique is particularly suited to meshing irregular boundaries with interior holes. This thesis presents an extension of the paving algorithm to generalized three dimensional surfaces. The major problems in three-dimensional surface mesh generation are projection of nodes, calculation of interior angles, and connection of mesh fronts. The solutions to these problems are presented. This work is part of the ongoing CUBIT project at Sandia Labs. The …

Determination Of The Parameter Limits For Artificial Non-Random Microwave Signal Detection, Irvin Lee Burough

Master's Theses - Daytona Beach

The Doppler shift of small bandwidth (several Hertz) microwave signals makes identification of spectral features difficult; the Doppler individual bandwidth shift can be a factor of hundreds or thousands of times greater than the bandwidth. A computer model supplied by the National Aeronautics and Space Administration's (NASA) Search for Extra-Terrestrial Intelligence (SETI) project, which can simulate radio frequency interference (RFI) and a buried ETI signal, will determine the limits of the signal-to-noise ratio (SNR) and false alarm threshold for identification of the signal after Doppler shifting. By running the model on a MicroVAX II computer, it will be possible to …

Using Computerized Cinematography To Develop A Predictive Model Relating Muscle Stress And Wrist Movement, Joseph M. Kaczmar

Honors Theses

Workers in many jobs are required to perform the same tasks day after day. As a result of this repetitious work, many employees are developing what is know as Cumulative Trauma Disorders (CTD). There has been much research done on ways to prevent these disorders. Cumulative Trauma Disorders involving the wrist are of special concern. Repetitive motions and awkward positions of the wrist are a major cause of CTD's in the wrist. One such factor dealing with the posture is the angle between the hand and the forearm. In order to help limit the affects of CTD's of the wrist, …

Formant Estimation From Dctc's Using A Feedforward Neural Network, Shubhangi U. Kelkar

Electrical & Computer Engineering Theses & Dissertations

Formants are the natural frequencies of the human vocal tract. Existing methods for estimating formants from speech signals are computationally complex and subject to errors for certain type of speech sounds. This thesis describes a method for estimating vowel formant frequencies from Discrete Cosine Transform Coefficients (DCTC's), a form of cepstral coefficients, using a feedforward neural network with back-propagation training. Experimental results are based on a large multispeaker data base. The results are obtained for both a linear transformation and a feedforward neural network with a nonlinear hidden layer. In general, the neural network transformation is superior to the linear …