Engineering Commons^™

Implementing Ray Tracing Algorithm In Parallel Environment, Tjah Jadi

Dissertations and Theses

Ray tracing is a very popular rendering algorithm in the field of computer graphics because it can generate highly-realistic images from three-dimensional models. Unfortunately, the computational cost is very expensive. To speed up the rendering process we present both static and dynamic scheduling (balancing) strategies for a multiprocessor system. Hence, the load balancing among the processors is the most important problem in parallel processing. The implementation of the algorithm is based on a modified octree structure.

A Cmos Circuit Generator Using Differential Pass Transistors For Implementing Boolean Functions, Rabe'eh Mahooti

Dissertations and Theses

This study uses differential pass transistor methodology for implementing and evaluating Boolean functions. The main goal is investigation of CMOS and nMOS approaches in pass transistor logic design. Pass-transistor logic is most effective in the implementation of Boolean functions when the vectors are in the same format. It has been demonstrated that nMOS pass transistor logic driven by a control signal voltage above the V_dd level offers a significant improvement in speed. nMOS pass transistorsalso offer less area consumption in comparison to the CMOS approach.

The philosophy developed here has been used in the design of a program for …

A Volume Integral Formulation For Electromagnetic Scattering From Homogeneous Dielectric Bodies, Mark Joseph Povinelli

Electrical Engineering and Computer Science – Theses

In recent years, printed circuit antennas have become very useful in conformal and planar phased array antenna systems. Of particular interest is the radiation and scattering performance of stripline and microstrip printed circuit antenna array-elements used in these systems. These ele­ments are generally made up of a complex three-dimensional distribution of dielectrics and con­ductors, which can include microstrip or stripline feed circuitry on a dielectric substrate. Figure 1 shows the geometry of a typical multilayer printed circuit stripline-fed flared slot antenna, used as an array-element in a multioctave planar phased array antenna. This antenna element design also incorporates a stripline …

Assessment Of Autonomic Regulation Of Heart Rate Variability, Shaw-Jyh Shin

Dissertations

Complex demodulation, accompanied by the techniques of interpolation, detrending and zero-phase-shift lowpass filtering were used to examine the effect of both divisions of the autonomic nervous system (sympathetic and parasympathetic) on heart rate by analyzing the heart rate variability signal from dogs under two different classical conditionings: CS+ and CS-, which cause different dynamic pattern changes in the autonomic nervous system to regulate the heart rate.

Unlike power spectral analysis, complex demodulation gives results in the time domain and shows the variation of amplitude and phase over time at a given frequency. The variation of phase indicates the frequency deviation …

A Silicon Photodiode Array For Soft X-Ray Sensing, Chih-Te Hu

Theses

An array of 30 x 30 sensing cells including logic within each cell and a self-scan address circuit are described. A unique scintillation technique is used to increase the threshold sensitivity 60dB for X-ray photon sensing beyond that obtainable with conventional photodiode sensors. Simulations for the sensing cell and some additional logic elements are based on SPICE version 2G5 and HILO 3. Worst case analysis includes variations in threshold voltage V_TP and V_TN for the CMOS circuit components. The final CMOS chip dimension using MOSIS 1.2 micron rules is 10mm x 10mm base on the 80 …

On Conventional And Harmonic Load Flow Analysis, Ranjit B. Pradhan

Theses

In conventional power flow analysis, simultaneous linear equations numbering in thousands must be solved repeatedly and in many instances on-line. Luckily the matrix of coefficients of these equations is sparse with a few elements in each row. Therefore for a faster solution and to save computer memory, sparsity must be exploited and an optimal ordering of the equations must be sought. When considering harmonics, the number of the simultaneous equations to be solved is multiplied and therefore, considering sparsity and optimal ordering is doubly important.

In this thesis a software package for optimizing computation time and memory requirements through exploitation …

System Performance Criteria In Cdma Networks Using Gold Codes, Yong H. Kim

Theses

First, we have presented the autocorrelation and crosscorrelation properties for periodic and aperiodic binary sequences. The generation of binary sequences using shift registers with feedback was reviewed. We have also included correlation properties for the Gold codes.

Next, we discussed Gold code generation for the balanced and unbalanced Gold codes.

Thirdly, we investigated the number of simultaneous users in a CDMA system using Gold codes for the worst case and the average case of mutual interference.

Finally, we simulated the probability of interference exceeding a threshold value, and the average crosscorrelation value caused by interference in a CDMA network which …

Modeling And Simulation Of Robot Arms With Flexible Links, John G. Danis

Theses

The design of lightweight robot arms introduces a degree of flexiblity in the individual links which renders the arm difficult to control. Solution of the control problem requires accurate and detailed mathematical models of the arm dynamics. A comprehensive survey of the current literature in this area has shown that although many such models exist, there is a great diversity in their structure, function, and applicability. The different objectives and techniques of model development which lead to this diversity are examined and summarized in this thesis. Bases for classification of the mathematical models and techniques of development are established, and …

An Investigation Of Electrical And Optical Properties Of Reactively Sputtered Silicon Nitride And Amorphous Hydrogenated Silicon Thin Films, Tae Hoon Kim

Theses

Thin films of silicon nitride and amorphous hydrogenated silicon were prepared by radio frequency reactive sputter deposition and their properties optimized for their use as low temperature passivation coatings for optoelectronic devices. The effect of various sputter deposition parameters on the conduction and optical properties were studied. Infrared spectrophotometry and ellipsometry were used to determined the optical properties of the films whereas the electrical properties were determined from current-voltage measurements of MIS capacitors.

Typical parameters of a sputter deposition run for the best Si₃N₄ films were: base pressure, 1-2x10^-6 torr; sputtering pressure, 5 mtorr; nitrogen partial …

Investigation Of Different Cmos Dram Sense Amplifier Configurations In Vlsi, Bihju Chiu

Theses

Sense amplifiers are particularly difficult circuits to design. In this work, only CMOS sense amplifiers are considered. There are typically two configurations of CMOS sense amplifiers: the cross-connected flip flop configuration and the current-mirror configuration. They are widely used nowadays with various modifications. These improved configurations are simulated and optimized with SPICE package, and their relative performances are also compared in this thesis.

Design Of A Fiber Optic Oxygen Sensor Based On Immobilized Hemoglobin, Mendu Govind Raj

Theses

The fiber optic Oxygen sensor consists of a thin layer of immobilized deoxyhemoglobin at the common end of a bifurcated fiber. Immobilization is done using the alginate gel procedure. The immobilized reagent is separated from the standard oxygen sample by the gel with or without semi-permeable membrane, and the entire configuration is enclosed in an oxygen free sample cell. Light from a tungsten-halogen lamp, filtered through a 405nm filter is passed through one arm of a bifurcated fiber to the sample cell. The reflected intensity (a highly polished aluminum foil or a plate is placed at the bottom of the …

Dc-Excited Cw Co₂ Metal Waveguide Laser, Fahad Saleh Al-Mashaabi

Dissertations and Theses

A novel design for a DC excited cw CO₂ metal waveguide laser has been developed in which a slotted hollow-cathode in a transverse discharge also doubles as a metal waveguide. This design has been implemented in a compact design that produces up to 1 watt of cw, 10.6 μm radiation. The discharge characteristics, laser gain and laser output has been studied as functions of various discharge parameters. The advantages of the new transverse discharge of the slotted hollow cathode geometry include low voltage, positive impedence and high optical gain. Overall efficiency is comparable with those of conventional longitudinal CO …

Electromagnetic Field Variations In The Activation Of Bone Cell Synthesis, Gary Ketcherside

Loma Linda University Electronic Theses, Dissertations & Projects

[Abstract Not Included]

Uniform Energy Discharge For Pulsed Lasers, Eric Calvin Koschmann

Retrospective Theses and Dissertations

The art of achieving a large energy discharge in a controlled manner with relative ease is to use a pulse forming network. Historically the design of such networks generally used a single inductor and capacitor. Although easy to design and implement, this practice does not provide optimum performance in all cases. In particular, most laser welding requires a uniform energy discharge in a pulse to produce a high quality weld. Analysis has shown that when the pulse forming network approximates a lumped constant transmission line a maximum flat pulse is produced with minimal degradation of the pulse rise time. This …

A Modified Extended Kalman Filter As A Parameter Estimator For Linear Discrete-Time Systems, Bruno Johannes Schnekenburger

Theses

This thesis presents the derivation and implementation of a modified Extended Kalman Filter used for Joint state and parameter estimation of linear discrete-time systems operating in a, stochastic Gaussian environment. A novel derivation for the discrete-time Extended Kalman Filter is also presented. In order to eliminate the main deficiencies of the Extended Kalman Filter, which are divergence and biasedness of its estimates, the filter algorithm has been modified. The primary modifications are due to Ljung, who stated global convergence properties for the modified Extended Kalman Filter, when used as a parameter estimator for linear systems.

Implementation of this filter is …

A New General Purpose Systolic Array For Matrix Computations, Hai Van Dinh Le

Dissertations and Theses

In this thesis, we propose a new systolic architecture which is based on the Faddeev's algorithm. Because Faddeev's algorithm is inherently general purpose, our architecture is able to perform a wide class of matrix computations. And since the architecture is systolic based, it brings massive parallelism to all of its computations. As a result, many matrix operations including addition, multiplication, inversion, LU-decomposition, transpose, and solutions to linear systems of equations can now be performed extremely fast. In addition, our design introduces several concepts which are new to systolic architectures:

- It can be re-configured during run time to perform different …

Logic Design Using Programmable Logic Devices, Loc Bao Nguyen

Dissertations and Theses

The Programmable Logic Devices, PLO, have caused a major impact in logic design of digital systems in this decade. For instance, a twenty pin PLO device can replace from three hundreds to six hundreds Transistor Transistor Logic gates, which people have designed with since the 60s. Therefore, by using PLD devices, designers can squeeze more features, reduce chip counts, reduce power consumption, and enhance the reliability of the digital systems.

This thesis covers the most important aspects of logic design using PLD devices. They are Logic Minimization and State Assignment. In addition, the thesis also covers a seldomly used but …

Voltage Controlled Resistance Model For Mos Transistors, Joey Zong-Yi Jia

Dissertations and Theses

The voltage controlled resistance model is developed for a reliable MOS transistor resistance mapping. The model includes both system and local parameters, and incorporates the effect of rise and fall time variations on the gate delay. MOS transistor resistance mapping is applied in logic simulation and timing verification. Also, it can be used in automatic transistor sizing and critical path analysis.

Finite Impulse Response Filter Design Using Cosine Series Functions, Carlton Delos Bishop

Retrospective Theses and Dissertations

Window functions have been extensively used for the design of SAW filters. The classical truncated cosine series functions, such as the Hamming and Blackmann functions, are only a few of an infinite set of such functions. The derivation of this set of functions from orthonormal basis sets and the criteria for obtaining the constant coefficients of the functions are presented. These functions are very useful because of the closed-form expressions and their easily recognizable Fourier transform. Another approach to the design of Gaussian shaped filters having a desired sidelobe level using a 40 term cosine series will be presented as …

Design Of A Bandpass Oculometer, Karin Brandauer

Retrospective Theses and Dissertations

A passive oculometer is a device that measures the position of the eye by utilizing the corneo-retinal potential (CRP) generated by the eye. In this thesis, the Bandpass Oculometer replaces the joystick of a personal computer, allowing the viewer to use a computer simply by moving his eyes. Low frequency noise, present in all electronic circuits, produces an offset from the reference point, the center of the screen. In previous lowpass oculometry studies at University of Central Florida, this offset caused the cursor to drift toward the edge of the field of view within a period of 30 seconds, decreasing …

Phase Noise Analysis And Basic Measuring Techniques, James A. Ferrell

Retrospective Theses and Dissertations

Oscillators are important elements of RF and microwave communications systems. The increased use of the electromagnetic spectrum requires the use of better and cleaner oscillators. Local oscillators in RF to IF converters play a big role in the overall performance of the receiver systems because phase noise in the local oscillator can drastically reduce the signal to noise ratio at the output of the receiver, especially if the converter is at the front end. Phase noise is the parameter used to describe oscillator stability. The analysis and basic measurement techniques of phase noise are performed in this report.

This research …

Rise Time To Frequency Correlation Of Crosstalk In Coupled Microstrip Lines, Charles Michael Fletcher Jr.

Retrospective Theses and Dissertations

An examination of forward crosstalk in microstrip transmission lines is presented through a computer simulation using SPICE. A non-resistive lumped L-C transmission line model is modified to include capacitive and inductive coupling from adjacent lines. Two adjacent microstrip transmission lines are modeled, and simulation results in both the time and frequency domains are shown. The time domain or transient analysis looks at the effect of rise times on crosstalk. Rise times in the range of 100 to 1000 nanoseconds (ns) are considered. The frequency analysis shows the crosstalk frequency response over the range of 100 to 1600 kilohertz (kHz). The …

Method For Sizing Mos Transistors For Vlsi, Matthew J. Amatangelo

Retrospective Theses and Dissertations

Determining the device width to length ratios has typically been an iterative process for the custom IC digital design engineer. After the logic design phase is complete for a particular circuit, the designer would make an educated guess at the device sizes. Then by trial and error, using SPICE or another circuit simulator, suitable sizes would be determined. Unfortunately, this approach is time consuming and the resulting sizes are often a good bit larger than they need to be to maintain a certain speed because of the lack of a rigorous sizing methodology. This paper describes a method for reducing …

A Piezoelectric Actuated Scanning Mirror System Utilizing A Type One Control Loop, David Gibbs

Retrospective Theses and Dissertations

The purpose of this thesis is to design and build an improved control loop for a piezoelectric actuated scanning mirror system. A control system has been built having zero steady state position error and an 80 Hertz bandwidth. This was achieved by placing the piezoelectric actuator in the feedback path of an operational amplifier and placing series cascaded notch filters and lead compensators in the forward path of the control loop. A prototype system, including compensation and feedback, is developed. Its performance compares favorably with that of the system model. It is capable of plus and minus 1.7 degrees of …

Laser Induced Darkening Semiconductor Dope Glasses, Jayant Malhotra

Retrospective Theses and Dissertations

No abstract provided.

A System For Measuring The Phase Difference Between Two Points Of A Propagating Laser Beam, Jefferson E. Odhner

Retrospective Theses and Dissertations

An optical system has been designed, analyzed, implemented, and calibrated which measures the phase difference between two points of a propagating laser beam. The system is a quadrature interferometer whose detector outputs are processed by a computer. This quadrature interferometer measures both the phase and amplitude variations between two points of a laser beam after the beam passes through turbulence . These measurements are in turn processed by a computer to isolate the phase variations from the amplitude variations. Further statistical analysis which can be performed on these phase variations should provide an understanding of the phase fluctuations of propagating …

Analysis Of Phase Noise In Phase Lock Loop, Diane Marie Pavik

Retrospective Theses and Dissertations

This research report presents an introduction into phase lock loops (PLL) with a major emphasis on calculating phase noise in frequency synthesizers. A PLL model that incorporates the major sources of noise is presented for the purpose of design analysis. The model can be used to analyze second and fifth order PLLs which allows the accurate calculation of phase noise as a function of independent variable design parameters. The stability of PLLs is also analyzed to show the effects of a marginally stable system on the resultant phase noise. Developing an accurate PLL model which accounts for the major sources …

A New Method For Broadband Surface Acoustic Wave Diffraction Analysis, Jacqueline Hanvey Hines

Retrospective Theses and Dissertations

This thesis describes an innovative technique for determining the impulse response of a SAW device including the effects of diffraction on both isotropic and anisotropic substrates. The approach presented is unique in that it determines the point-to-point impulse response for the isotropic case using the two-dimensional wave equation, and utilizes a double integral reduction technique to determine the tap-to-tap response, thereby significantly reducing the complexity of the calculations involved. An extension is then made to describe the impulse response of two cascaded transducers of arbitrary geometry, along with some simplifying cases. Previous attempts to model diffraction effects generally utilized either …

Uniformity Correction For A Scanned Long Wavelength Infrared Focal Plane Array, George C. Heinold

Retrospective Theses and Dissertations

This paper presents an alternative approach in providing uniformity correction for an infrared focal plane array by utilizing analog MOSFET circuitry. This technology is compatible with modern VLSI production and is capable of enhanced operation at cryogenic temperatures. The method presented here is a potential contribution to the growing list of special analog circuit configurations which may be incorporated for on-chip signal processing, inside the cryogenic dewar assembly. Electronic packaging of current thermal systems could be significantly reduced in size and weight by trading some of the cumbersome digital algorithms and complex post-processing circuitry for implementation in VLSI form.

The …

Applications Of Lattice Filters To Quadrature Mirror Filter Banks, Gregory R. Jaspers

Retrospective Theses and Dissertations

Presented is a method for designing and implementing lattice filters to be used in Quadrature Mirror Filter (QMF) Banks. Quadrature Mirror Filter Banks find use in applications where a signal must be spilt into subbands operated on then reconstructed in the output. Because of their structure, lattice filters do this very well and allow perfect reconstruction, even when the lattice coefficients must be quantized. In this paper QMF's and Lattice Filters are derived and analyzed. Application of the lattice filter is presented along with a design program and example of its use to implement a QMF. The computer aided design …