Digital Commons Network^™

Simulation Of Activity Rhythms In The Hamster, Paul Qassis

Theses

In this research, an effort was made to better understand light-dark cycles which influence the physiological and psychological rhythms, circadian rhythms and their behavior. The research concentrated on mathematically modeling circadian rhythms (specifically hamsters' circadian activity rhythms) and establishing a physical correlation and creating a meaningful relationship between the mathematical model's parameters and the real biological oscillators which are responsible for these rhythms. The internal nature of the circadian rhythms is unclear. There is insufficient information and empirical data that describe them. Indirect means have to be employed for the description and exploration of such rhythms. Extensive real data analysis …

Multilevel Block Coded 8-Psk Modulations Using Unequal Error Protection Codes For The Rayleigh Fading Channel, Robert H. Morelos-Zaragoza, Tadeo Kamasi, Shu Lin

Faculty Publications

This paper introduces new block coded 8-PSK modulations with unequal error protection (UEP) capabilities for Rayleigh fading channels. The design of efficient block coded modulations (BCM) over 8-PSK signal sets, for the specific purpose of UEP, over Rayleigh fading channels is considered. UEP is desirable in communications systems where part of the source information is more important, or error sensitive, such as the transmission of coded speech and data broadcasting. The proposed block modulation codes are based on the multilevel construction of Imai and Hirakawa (1977). It is shown that the use of binary linear UEP (LUEP) codes as component …

Qpsk Block-Modulation Codes For Unequal Error Protection, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

Unequal error protection (UEP) codes find applications in broadcast channels, as well as in other digital communication systems, where messages have different degrees of importance. Binary linear UEP (LUEP) codes combined with a Gray mapped QPSK signal set are used to obtain new efficient QPSK block-modulation codes for unequal error protection. Several examples of QPSK modulation codes that have the same minimum squared Euclidean distance as the best QPSK modulation codes, of the same rate and length, are given. In the new constructions of QPSK block-modulation codes, even-length binary LUEP codes are used. Good even-length binary LUEP codes are obtained …

Design And Construction Of An Active Alignment Demonstrator For A Free-Space Optical Interconnect, G. C. Boisset, B. Robertson, Harvard Scott Hinton

Electrical and Computer Engineering Faculty Publications

An x-y active alignment system based on Risley beam steerers is described. The demonstrator features a quadrant detector which detects the misalignment error between the center of a spot of light and the center of the quadrant detector. This misalignment error is then used by a new algorithm to calculate the rotational displacement required for the two Risley beam steerers to steer the spot of light to the center of the quadrant detector. The experimental results indicate that any spot misaligned by up to 160 μm on the quadrant detector will be systematically centered by the demonstrator system.

Finite Impulse Response Utilizing The Principles Of Superposition, Scott Edward Carter

Retrospective Theses and Dissertations

Window functions have been greatly utilized in the synthesis of finite impulse response (FIR) filters implemented using surface acoustic wave (SAW) devices. The critical parameter in any FIR design in the impulse response length, which must be optimized for the given design specifications in order to reduce the size of each device. To this end, many design algorithms have been introduced such as Remez exchange, linear programming, and least mean squares. A new algorithm has been derived which is efficient and accurate for the design of arbitrary filter specifications requiring less computations than the current algorithms. The FIR design is …

Enhanced 911 Service In A Private Branch Exchange Using Uswest Ps/Ali Service

ACUTA: Other Publications

In This Issue

Author

Introduction

EP11 Operation Overview

US West Communications E911 Private Switch/Automatic Location

Identification Feature

Implementation of E911 with PS/ALI At Colorado State University

Overview

Planning ALI Database Input

SL- 100 PBX Database and Trunking

Pre-Testing

Other Issues and Difficulties

Cost

Conclusion

Addendum A

Addendum B

Using Matlab To Illustrate The 'Phenomenon Of Aliasing', Sol Neeman, Ph.D.

Engineering Studies Faculty Publications and Creative Works

The phenomenon of aliasing is important when sampling analog signals. In cases where the signal is bandlimited, one can avoid aliasing by ensuring that the sampling rate is higher than the Nyquist rate . But in cases where the signal is not bandlimited , aliasing is unavoidable if the signal is not filtered before it is sampled. It is then crucial to understand the phenomenon in order to estimate the distortion generated when the signal is reconstructed from its samples. Using the software package MATLAB by MathWorks, Inc ., two examples are presented. The first is a pure sinusoid which …

A Silicon Knife Design And Fabrication, Mingli Wang

Theses

In this thesis, the design and fabrication of a silicon knife is described. The device design is based on the principle of oxidation sharpening.

The knife is made from a silicon wafer and can be made to be any chosen length up to 150 mm. It was made with the same basic procedures used in semiconductor chip manufacturing. This type of processing/manufacturing results in a knife with a high degree of sharpness and smoothness compared with existing knife technology.

The knife fabrication plan combines IC processing, techniques including anisotropic and isotropic etching of silicon, plasma dry etching and chemical etching …

Calculating Cross Slot Flux Losses In High Voltage Stator Coils, John D. Amos

Retrospective Theses and Dissertations

At present there are several methods for calculating temperature for inner-cooled stator coils for large electric generators. Determining the highest temperature in a stator coil is very important and is a major limiting factor for the maximum capability of steam turbine synchronous generators.

The load current in the stator winding causes losses in the conductor resistance. That same current excites leakage fluxes that link contours inside the conductors causing non-uniform current distribution and additional losses. these additional losses are caused by eddy currents induced inside the stator coils. These eddy losses are grouped as radial flux losses, cross slot flux …

Analysis And Extension Of Model-Based Software Executives, Keith E. Lewis

Theses and Dissertations

This research developed a comprehensive description of the simulation environment of Architect, a domain-oriented application composition system being developed at the Air Force Institute of Technology to explore new software engineering technologies. The description combines information from several previous research efforts and Architect's source code into a single, comprehensive document. A critical evaluation of the simulation environment was also performed, identifying improvements and modifications that enhance Architecture's application execution capabilities by reducing complexity and execution time. The analysis was then taken one step further and presented extensions to the current simulation environment. The extensions included investigating the feasibility of mixed-mode …

On The Carrier Mobility In Forward-Biased Semiconductor Barriers, Mark S. Lundstrom, Shin'ichi Tanaka

Department of Electrical and Computer Engineering Faculty Publications

A simple one-speed solution to the Boltzmann equation is used to evaluate the mobility and diffusion coefficient for carriers in forward-biased semiconductor barriers. The analysis shows that although the average kinetic energy of carriers remains near thermal equilibrium, the mobility and diffusion coefficient are strongly reduced by the built-in field. Conventional macroscopic transport equations, which treat the carrier mobility and diffusion coefficient as single valued functions of the kinetic energy will improperly treat transport in forward-biased barriers. The results are important for the careful analysis of metal–semiconductor and heterojunction diodes.

On The Carrier Mobility In Forward-Biased Semiconductor Barriers, Mark S. Lundstrom, S. I. Tanaka

Department of Electrical and Computer Engineering Faculty Publications

A simple one-speed solution to the Boltzmann equation is used to evaluate the mobility and diffusion coefficient for carriers in forward-biased semiconductor barriers. The analysis shows that although the average kinetic energy of carriers remains near thermal equilibrium, the mobility and diffusion coefficient are strongly reduced by the built-in field. Conventional macroscopic transport equations, which treat the carrier mobility and diffusion coefficient as single valued functions of the kinetic energy will improperly treat transport in forward-biased barriers. The results are important for the careful analysis of metal-semiconductor and heterojunction diodes.© 1995 American Institute of Physics.

Transition Matrix Approach For Monte Carlo Simulation Of Coupled Electron/Phonon/Photon Dynamics, Muhammad A. Alam, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

A new approach for simulating the dynamics of electrons, phonons, and photons is described. The technique provides a Monte Carlo simulation of particle dynamics without the statistical noise associated with direct Monte Carlo simulation, treats physical phenomena with a wide range of time scales, and has a good computational efficiency. A transition matrix is first precomputed by direct Monte Carlo simulation. Particle populations are then updated at regular time steps by simple matrix multiplication while correcting for nonlinear effects such as carrier–carrier scattering, band filling, hot phonons, etc. The technique is well suited to studies of quantum well laser devices …

Temperature Dependence Of Minority And Majority Carrier Mobilities In Degenerately Doped Gaas, Michael L. Lovejoy, Michael R. Melloch, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Measured minority and majority carrier mobility temperature dependencies in heavily doped n- and p-GaAs are compared. Majority carrier mobilities in heavily doped GaAs are essentially temperature ~T! independent while minority carrier mobilities exhibit a roughly 1/T dependence. Majority carrier freezeout, which reduces both majority–minority carrier and ionized impurity scattering, is shown not to be responsible for the 1/T minority carrier mobility dependence. The difference in minority and majority carrier mobility T dependencies is explained in terms of the increased degree of degeneracy of majority carriers with decreased temperature, which decreases majority–minority carrier scattering.

Characterization Of Photon Recycling In Thin Crystalline Gaas Light Emitting Diodes, M. P. Patkar, M. S. Lundstrom, Michael R. Melloch

Department of Electrical and Computer Engineering Faculty Publications

Gallium arsenide light emitting diodes (LEDs) were fabricated using molecular beam epitaxial films on GaAs substrates and removed by epitaxial lift-off (ELO). Lifted off devices were then mounted on a Si wafer using a Pd/Au/Cr contact layer, which also served as a back surface reflector. Devices were characterized by electrical and optical measurements, and the results for devices on the GaAs substrate were compared to those for EL0 devices. EL0 LEDs coated with a ZnS/MgF2 antireflection coating exhibited an optical output that was up to six times that of LEDs on GaAs substrates. At the same time, the measured current-voltage …

Beam Modes Of Lasers With Misaligned Complex Optical Elements, Anthony A. Tovar

Dissertations and Theses

A recurring theme in my research is that mathematical matrix methods may be used in a wide variety of physics and engineering applications. Transfer matrix techniques are conceptually and mathematically simple, and they encourage a systems approach. Once one is familiar with one transfer matrix method, it is straightforward to learn another, even if it is from a completely different branch of science. Thus it is useful to overview these methods, and this has been done here. Of special interest are the applications of these methods to laser optics, and matrix theorems concerning multipass optical systems and periodic optical systems …

Maximum Rate Of Change Of The Differential Reflection Phase Shift With Respect To The Angle Of Incidence For Light Reflection At The Surface Of An Absorbing Medium: Èrratum, R. M.A. Azzam, A. M. El-Saba

Electrical Engineering Faculty Publications

No abstract provided.

Applying Neural Networks To Find The Minimum-Cost Coverage Of A Boolean Function, Pong P. Chu

Electrical and Computer Engineering Faculty Publications

To find a minimal expression of a boolean function includes a step to select the minimum cost cover from a set of implicants. Since the selection process is an NP-complete problem, to find an optimal solution is impractical for large input data size. Neural network approach is used to solve this problem. We first formalize the problem, and then define an ''energy function'' and map it to a modified Hopfield network, which will automatically search for the minima. Simulation of simple examples shows the proposed neural network can obtain good solutions most of the time.

Learning To Ignore: Psychophysics And Computational Modeling Of Fast Learning Of Direction In Noisy Motion Stimuli, Lucia M. Vaina, V. Sundareswaran, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

The effects of practice on the discrimination of direction of motion in briefly presented noisy dynamic random dot patterns are investigated in several forced-choice psychophysical tasks. We found that the percentage of correct responses on any specific task increases linearly with repetition of trials within roughly 200 trials from about chance to a performance of 90% or better. The level of performance remained constant or improved over several days, and in most instances, it did not transfer when stimulus parameters changed. We used a modified Radial Basis Function (RBF) representation to model the psychophysical tasks. The performance of the model …

The Performance Of Reed-Solomon Codes On A Bursty-Noise Channel, William J. Ebel, William H. Tranter

Electrical and Computer Engineering Faculty Research & Creative Works

The performance of a Reed-Solomon coded binary communication system on a bursty-noise channel is considered. Bursty noise is defined to be background Gaussian noise plus burst noise, where burst noise is defined to be a series of finite-duration Gaussian-noise pulses with fixed duration and Poisson occurrence times. Using the noise model, along with ideal symbol interleaving, decoded bit-error probability bounds are derived for the case where the noise bursts are long with respect to the channel symbol rate. Specific performance results are presented for the (31,15,8) Reed-Solomon Joint Tactical Distribution System (JTIDS) code with a Binary Phase Shift Keyed (BPSK) …

Remote Detection Of Acoustic Boundaries Using Radiation Imaging Operators, Richard E. Dubroff, Md. Ishfaqur Raza, Thomas J. Herrick

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we present an acoustic imaging operator. This operator is based upon combining the material boundary conditions at an acoustic boundary and the radiation boundary conditions associated with one way wave propagation. Numerical examples, using the second-order imaging operator, are presented in order to demonstrate the applicability of this method to the detection of two-dimensional boundaries.

Hardware Assists For High Performance Computing Using A Mathematics Of Arrays, Hardy J. Pottinger, W. Eatherton, J. Kelly, T. Schiefelbein, Lenore Mullin, R. Ziegler

Electrical and Computer Engineering Faculty Research & Creative Works

Work in progress at the University of Missouri-Rolla on hardware assists for high performance computing is presented. This research consists of a novel field programmable gate array (FPGA) based reconfigurable coprocessor board (the Chameleon Coprocessor) being used to evaluate hardware architectures for speedup of array computation algorithms. These algorithms are developed using a Mathematics of Arrays (MOA). They provide a means to generate addresses for data transfers that require less data movement than more traditional algorithms. In this manner, the address generation algorithms are acting as an intelligent data prefetching mechanism or special purpose cache controller. Software implementations have been …

A Universal Power Converter For Emergency Charging Of Electric Vehicle Batteries, Norman R. Cox

Electrical and Computer Engineering Faculty Research & Creative Works

An on-board electric vehicle battery charger capable of accepting AC or DC inputs in the range of 12 to 260 volts is described. The charger provides near-unity power factor and high efficiency for routine charging from AC sources, but can also be used to tap other sources of power in the event of an emergency.

Conservative Thirty Calendar Day Stock Prediction Using A Probabilistic Neural Network, H. Tan, Donald C. Wunsch, Danil V. Prokhorov

Electrical and Computer Engineering Faculty Research & Creative Works

We describe a system that predicts significant short-term price movement in a single stock utilizing conservative strategies. We use preprocessing techniques, then train a probabilistic neural network to predict only price gains large enough to create a significant profit opportunity. Our primary objective is to limit false predictions (known in the pattern recognition literature as false alarms). False alarms are more significant than missed opportunities, because false alarms acted upon lead to losses. We can achieve false alarm rates as low as 5.7% with the correct system design and parameterization.

Performance Of Ai Methods In Detecting Melanoma, Arve Kjoelen, M. J. Thompson, Scott E. Umbaugh, Randy Hays Moss, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

This research has shown that features extracted from color skin tumor images by computer vision methods can be reliable discriminators of malignant tumors from benign ones. Reliability was demonstrated by the monotonically increasing success ratios with increasing training set size and by the small standard deviations from the mean success rates. An average success rate of 70 percent in diagnosing melanoma was attained for a training set size of 60 percent. The presence or absence of atypical moles in the training and test sets was shown to have a dramatic impact on the effectiveness of the generated classification rules. This …

Least Squares Order-Recursive Lattice Smoothers, Jenq Tay Yuan, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

Conventional Least Squares Order-Recursive Lattice (LSORL) Filters Use Present and Past Data Values to Estimate the Present Value of a Signal. This Paper Introduces LSORL Smoothers Which Use Past, Present and Future Data for that Purpose. Except for an overall Delay Needed for Physical Realization, LSORL Smoothers Can Substantially Outperform LSORL Filters While Retaining All the Advantages of an Order-Recursive Structure. © 1995 IEEE

Cossap Simulation Model Of Ds-Cdma Indoor Microwave Atm Lan, Keng T. Tan

Theses : Honours

This thesis presents an original work in the area of designing and implementing a simulation testbed for modelling a high speed spread spectrum Asynchronous Transfer Mode (ATM) Local Area Network (LAN). The spread spectrum technique used in this LAN model is Direct Sequence Code Division Multiple Access (DS-CDMA). The simulation model includes at least a physical layer of such a LAN, embedded into the COSSAP¹ simulation environment, and has been fully tested. All the newly developed building blocks are comprised of standard blocks from the COSSAP libraries or compatible user-built primitive blocks (only where it is absolutely necessary), and …

Application Of Improved Pressure Transducers For Pressure Measurements, P Mtui

Tanzania Journal of Engineering and Technology (TJET)

Substantial improvement of low sensitivity pressure transducers aiming at obtaining a more realistic output signal is discussed. The output signal direct from these transducers has deficiencies of amplitude attenuation and phase lag, thus the measured values are not necessarily the true in- stantaneous values. In order to correct for such shortcomings the unit step response of these transducers is also studied experimentally. A math- ematical model is established based on the experimental results to build up a compensation circuit which is then included in the instrumentation setup to eliminate these deficiencies. The effectiveness of the compensated transducer is demonstrated by …

Survey And Implementation Of Commercial Manual Controllers For A Generic Telerobotics Architecture, Thomas E. Deeter

Theses and Dissertations

The purpose of this study is to determine an input device for the Air Force's generic telerobotics architecture for large aircraft maintenance and repair. One area of concern is the human to machine interface, more specifically, which manual controller should be used for the specified tasks in this architecture. We mailed a survey to 68 companies in order to compile a list of possible input devices that the telerobotics architecture could use. 32 companies responded which gave me enough data to generate a list that described the physical traits of the input devices. We then divided the required tasks into …

Instability In Self-Pulsation In Laser Diodes And Its Effect On All-Optical Synchonization, Jonathan Hyland, Gerald Farrell

Articles

The effect of short- and long-term frequency instability in self pulsation on all-optical synchronization using a twin-section laser diode is experimentally investigated. Short-term frequency instability broadens the unlocked full width at half maximum (FWHM) of the fundamental of the rf spectrum of the self-pulsating laser diode. We show experimentally that the value of the unlocked FWHM, and thus the level of short-term instability, has a direct effect on the optical power required to maintain synchronization. A novel means of reducing the FWHM is presented based on a reflective transmission line stub connected to the absorber of the twin-section self-pulsating laser …