Digital Commons Network^™

Noise Reduction With Microphone Arrays For Speaker Identification, Zachary Gideon Cohen

Master's Theses

The presence of acoustic noise in audio recordings is an ongoing issue that plagues many applications. This ambient background noise is difficult to reduce due to its unpredictable nature. Many single channel noise reduction techniques exist but are limited in that they may distort the desired speech signal due to overlapping spectral content of the speech and noise. It is therefore of interest to investigate the use of multichannel noise reduction algorithms to further attenuate noise while attempting to preserve the speech signal of interest.

Specifically, this thesis looks to investigate the use of microphone arrays in conjunction with multichannel …

Smart Wall Plug Design For The Dc House Project, Edward Constant Sibal

Master's Theses

The DC House project at Cal Poly State University faces a challenge of supplying DC voltage to household appliances. Each appliance in the DC House constitutes a DC load that has a unique voltage and power rating, hence the need to develop a smart DC wall plug that will automatically adjust to the operating voltage required by any DC load. This thesis entails a proof of concept design of the smart DC wall plug which can automatically detect an appliance’s voltage rating. The design employs a dc-dc converter in conjunction with a microcontroller to sense load current to properly adjust …

Early Forest Fire Detection Using Texture, Blob Threshold, And Motion Analysis Of Principal Components, Georges Fouad Moussa

Master's Theses

Forest fires constantly threaten ecological systems, infrastructure and human lives. The purpose behind this study is minimizing the devastating damage caused by forest fires. Since it is impossible to completely avoid their occurrences, it is essential to accomplish a fast and appropriate intervention to minimize their destructive consequences. The most traditional method for detecting forest fires is human based surveillance through lookout towers. However, this study presents a more modern technique. It utilizes land-based real-time multispectral video processing to identify and determine the possibility of fire occurring within the camera’s field of view. The temporal, spectral, and spatial signatures of …

Radio Direction Finding Network Receiver Design For Low-Cost Public Service Applications, Marcel Colman Eric Stieber

Master's Theses

A low-cost radio direction finding (RDF) VHF receiver has been investigated for development into a radio direction finding network (RDFN) with a particular focus towards public service and commercial asset tracking applications. The primary design criteria were reproducibility, low-cost, and simplicity such that public service and volunteer organizations can benefit from the technology. Two receiver designs were built and tested to allow for comparison of practicality, cost, and accuracy. A pseudo-Doppler RDF and a time difference of arrival (TDOA) receiver were built as proof-of-concept for a system design based on commercial off-the-shelf (COTS) components. The pseudo-Doppler system is a less …

Constant Conduction Angle Biasing For Class C Monolithic Rf Power Amplifiers, Gursewak Singh Rai

Master's Theses

In modern wireless communication systems, a base station typically serves a few hundred users within its cell coverage. To combat the near-far problem – the situation where a nearby user’s strong cellular signal masks the cellular signal of a faraway user – base stations continually enforce power control. That is, nearby users must lower their transmit power. In CDMA technology, power control can be as large as 70-80dB. At low power outputs, this greatly impacts the performance of the RF power amplifier (PA) in the cellular device. For small RF drives, the magnitude of the output RF current approaches the …

A Resistance Based Structural Health Monitoring System For Composite Structure Applications, Dennis N. Boettcher

Master's Theses

This research effort explored the possibility of using interwoven conductive and nonconductive fibers in a composite laminate for structural health monitoring (SHM). Traditional SHM systems utilize fiber optics, piezoelectrics, or detect defects by nondestructive test methods by use of sonar graphs or x-rays. However, these approaches are often expensive, time consuming and complicated.

The primary objective of this research was to apply a resistance based method of structural health monitoring to a composite structure to determine structural integrity and presence of defects.

The conductive properties of fiber such as carbon, copper, or constantan - a copper-nickel alloy - can be …

Touchspice Vs. Reactive-Spice: A Human-Computer Interaction Perspective, Joshua Martin O'Hara

Master's Theses

Traditional SPICE simulation tools and applications of circuit theory lack real-time interaction and feedback. The goal of this thesis was to create an interactive physical environment to allow the manipulation and simulation of discrete electrical components in near-real-time while optimizing and streamlining the human-computer interaction (HCI) elements to make the user experience as positive and transparent as possible. This type of HCI and near-real-time simulation feedback would allow for the instant realization of how the parameters of each discrete component or hardware module affect the overall simulation and response of the circuit.

The scope of this thesis is to research, …

Fabrication And Characterization Of Torsional Micro-Hinge Structures, Mike Madrid Marrujo

Master's Theses

ABSTRACT

Fabrication and Characterization of Torsional Micro-Hinge Structures

Mike Marrujo

There are many electronic devices that operate on the micrometer-scale such as Digital Micro-Mirror Devices (DMD). Micro actuators are a common type of DMD that employ a diaphragm supported by torsional hinges, which deform during actuation and are critical for the devices to have high stability and reliability. The stress developed within the hinge during actuation controls how the actuator will respond to the actuating force. Electrostatically driven micro actuators observe to have a fully recoverable non-linear viscoelastic response. The device consists of a micro-hinge which is suspended by two …

The Effect Of Polarization And Ingan Quantum Well Shape In Multiple Quantum Well Light Emitting Diode Heterostructures, Patrick M. Mcbride

Master's Theses

Previous research in InGaN/GaN light emitting diodes (LEDs) employing semi-classical drift-diffusion models has used reduced polarization constants without much physical explanantion. This paper investigates possible physical explanations for this effective polarization reduction in InGaN LEDs through the use of the simulation software SiLENSe. One major problem of current LED simulations is the assumption of perfectly discrete transitions between the quantum well (QW) and blocking layers when experiments have shown this to not be the case. The In concentration profile within InGaN multiple quantum well (MQW) devices shows much smoother and delayed transitions indicative of indium diffusion and drift during …

Spectral Shape Division Multiplexing (Ssdm): Apparatus, Transmitter, Receiver And Detection, Fausto Daniel Holguín-Sánchez

Master's Theses

Wireless communication companies require to use the frequency spectrum to operate. Both frequency licenses and infrastructure to reuse frequencies are costly resources subject to increasing demand. This work introduces a novel multiplexing method that saves spectrum called Spectral Shape Division Multiplexing (SSDM). Under certain configurations, SSDM displays higher flexibility and throughput than other spectrally efficient methods.

SSDM defines the structure of a wireless multi-carrier by software. It is similar to Orthogonal Frequency Division Multiplexing (OFDM) in that both use overlapped sub-carriers to make efficient use of allocated spectrum. However, SSDM has several advantages. Where OFDM organizes sub-carriers orthogonally, SSDM allows …

A Proposed Control Solution For The Cal Poly Wind Energy Capture System, Kent R. Burnett

Master's Theses

The focus of this thesis is to research, analyze, and design a reliable and economical control system for the Cal Poly Wind Energy Capture System (WECS). A dynamic permanent magnet generator model is adopted from [1] and [2] and combined with an existing wind turbine model to create a non-linear time varying model in MATLAB. The model is then used to analyze potentially harmful electrical disturbances, and to define safe operating limits for the WECS. An optimal operating point controller utilizing a PID speed loop is designed with combined optimization criteria and the final controller design …

Light Extraction Enhancement Of Gan Based Leds Using Top Gratings, Patterned Sapphire Substrates, And Reflective Surfaces, Greg Chavoor

Master's Theses

In the last 15 years, an immense amount of research has gone into developing high efficiency Gallium Nitride based light emitting diodes (LED). These devices have become increasingly popular in LED displays and solid state lighting. Due to the large difference in refractive index between GaN and Air, a significant amount of light reflects at the boundary and does not escape the device. This drawback decreases external quantum efficiency (EQE) by minimizing light extraction. Scientists and engineers continue to develop creative solutions to enhance light extraction. Some solutions include surface roughening, patterned sapphire substrates, and reflective layers.

This study proposes …

Reliable Software Updates For On-Orbit Cubesat Satellites, Sean Fitzsimmons

Master's Theses

CubeSat satellites have redefined the standard solution for conducting missions in space due to their unique form factor and cost. The harsh environment of space necessitates examining features that improve satellite robustness and ultimately extend lifetime, which is typical and vital for mission success. The CubeSat development team at Cal Poly, PolySat, has recently redefined its standard avionics platform to support more complex mission capabilities with this robustness in mind. A significant addition was the integration of the Linux operating system, which provides the flexibility to develop much more elaborate protection mechanisms within software, such as support for remote on-orbit …

Linear Power-Efficient Rf Amplifier With Partial Positive Feedback, Matthew E. King

Master's Theses

Over the last decade, the number of mobile wireless devices on the market has increased substantially. New “multi-carrier” modulation schemes, such as OFDM, WCDMA, and WiMAX, have been developed to accommodate the increasing number of wireless subscribers and the demand for faster data rates within the limited commercial frequency spectrum. These complex modulation schemes create signals with high peak-to-average power ratios (PAPR), exhibiting rapid changes in the signal magnitude. To accommodate these high-PAPR signals, RF power amplifiers in mobile devices must operate under backed-off gain conditions, resulting in poor power efficiency. Various efficiency-enhancement solutions have been realized for backed-off devices …

3d Electromagnetic Simulation Tool Exposure For Undergraduate Electrical Engineers: Incorporation Into An Analog Filters Course, Bobby B. Pheng

Master's Theses

With the growth of wireless communications, comes the need for engineers knowledgeable in 3D electromagnetic (EM) simulation of high-frequency circuits. To give electrical engineering students a better understanding of the behavior of electromagnetic fields, experiments including the use of 3D EM simulation software were proposed. Most students get lost in differential equations, curls, and divergences; this thesis aims to remedy that by exposing them to 3D EM simulation, which may motivate them toward further study in electromagnetics. Also, experience using EMPro is very beneficial for future RF/microwave/antenna engineers, as use of 3D EM simulation is becoming a requirement for this …

Design Of Dc Light Bulb For The Dc House Project, Kent Chin Liang

Master's Theses

This thesis focuses on the design and implementation of an economical and energy efficient DC Light Bulb for the DC House Project. For the DC lighting system, emphasis is on the DC-DC LED driver, dimmer circuit, LED lighting array, and physical packing design. In this paper, a DC Light Bulb is designed, simulated, and tested to operate at a wide input voltage ranging from 24 VDC to 72 VDC, to be fully dimmable using pulse-width modulation technique, and to produce lumination intensities equivalent to a standard 100 W A19 incandescent light bulb at one-tenth the total power consumption. The DC …

Evaluation Of A Novel Axial Flux Variable Reluctance Machine, Derek Braden Hines

Master's Theses

The objective of this thesis is to determine the feasibility of a novel axial flux variable reluctance machine design. The design aims to compete with prevalent rare-earth permanent magnet machines while also implementing an innovative torque ripple minimization strategy. Given the fundamental operating principles, a selection of dimensions, materials, and excitations are prepared for the machine. Special attention is given to the rotor profile which is crucial to operation. Finite element analysis software is used to evaluate a three-dimensional model in terms of inductance and torque. The ultimate potential of the machine is discussed and recommendations for improvement are proposed.

Energy Harvesting From Elliptical Machines: Dc-Dc Converter Design Using Sepic Topology, Martin Kou

Master's Theses

Cal Poly’s ongoing Energy Harvesting from Exercise Machines (EHFEM) project is a very convenient and cost-effective way for generating DC power from physical exercise and sending it back to the electrical grid as AC power, providing a renewable energy source for the future. The EHFEM project consists of numerous subprojects involving converting different types of exercise machines for power generation. This project is a continuation of one of the previous subprojects, specifically involving an elliptical machine, and focuses on improving system functionality at different machine settings without altering the elliptical user’s experience by selecting a new DC-DC converter design, while …

Touchspice: Physical-Virtual Circuit Emulator, Kevin Christopher Peters

Master's Theses

This thesis involves the creation of a system of embedded touchscreen devices called touchSPICE to aid in the learning of basic circuits. Traditionally, circuit theory is taught to students in two different methods, lectures and laboratory exercises. Lectures focus on auditory and visual learning and are largely passive learning. Lab experiments allow students to physically interact with the circuits, and learn visually through viewing output waveforms from simulators or on measurement devices. The goal of the touchSPICE project is to develop a physical system for virtual, real-time SPICE simulation that mimics the laboratory experience. In touchSPICE, touchscreen devices act as …

Uniting The Nation's Power Grids: Opening Markets To Integrate Large Scale Renewable Power, Jeffrey Kenneth Wilkinson

Master's Theses

As renewable energy becomes increasingly cost competitive and Renewable Portfolio Standards (RPS) push states to produce more and more of their steadily growing power demands from renewable sources, the need to solve the problems associated with renewable penetration becomes a priority. The intermittent nature of solar and wind power generation require additional cost that inhibit their implementation as penetration levels grow. Reliability remains power utilities' top priority while they struggle to upgrade their systems. Old generation facilities will be decommissioned, renewable energy projects will come on line and transmission upgrades become inevitable. Variability on the grid is currently mitigated through …

Study Of Statistical And Computational Intelligence Methods Of Detecting Temporal Signature Of Forest Fire Heat Plume From Single-Band Ground-Based Infrared Video, Daniel G. Kohler

Master's Theses

This thesis will analyze video from land-based, cooled mid-wave infrared cameras to identify temporal features indicative of a heat plume from a forest fire. Desirable features and methods will show an ability to distinguish between heat plume movement and other movements, such as foliage, vehicles, humans, and birds in flight. Features will be constructed primarily using combinations of statistics and principal component analysis (PCA) with intent to detect key characteristics of fire and heat plume: persistence and growth. Several classification systems will combine and filter the features in an attempt to classify pixels as either heat or non-heat. The classification …

Cascaded High Voltage Converter With Variable Control For Pulsed Electric Field Applications, Emmanuel Loza

Master's Theses

Living a sustainable lifestyle while facing increasing population and decreasing natural resources has become one of humanity’s largest challenges. Locating fossil fuels is becoming more difficult while the demand for them to power our societies is ever increasing. Instead of finding more efficient methods of extracting fossil fuels, developing technologies that create renewable substitutes for fossil fuels is now the strategy. Algae biofuel matches fossil fuel performance while also meeting the criteria for renewable energy. The focus now shifts to finding methods for commercially producing algae biofuel. Therefore, the objective of this thesis is to develop a system that provides …

Real-Time Musical Analysis Of Polyphonic Guitar Audio, John E. Hartquist

Master's Theses

In this thesis, we analyze the audio signal of a guitar to extract musical data in real-time. Specifically, the pitch and octave of notes and chords are displayed over time. Previous work has shown that non-negative matrix factorization is an effective method for classifying the pitches of simultaneous notes. We explore the effect of window size, hop length, and other parameters to maximize the resolution and accuracy of the output.

Other groups have required prerecorded note samples to build a library of note templates to search for. We automate this step and compute the library at run-time, tuning it specifically …

Modeling And Analysis Of A Photovoltaic System With A Distributed Energy Storage System, Anthony Winston Ma

Master's Theses

As California continues to integrate more renewable energy into its electrical system, the state has experienced a corresponding rise in photovoltaic system installations. PV arrays are a unique source of power generation in that they are affected by the location of the sun, shading, and temperature changes. These characteristics make solar one of the most highly variable forms of renewable energy. In order to improve solar power’s consistency, PV systems require a supplemental source of power. The primary focus of this paper is to determine if distributed energy storage systems can be used to reduce the effect of solar intermittency. …

Multi-Circle Detections For An Automatic Medical Diagnosis System, Dingran Lu

Master's Theses

Real-time multi-circle detection has been a challenging problem in the field of biomedical image processing, due to the variable sizes and non-ideal shapes of cells in microscopic images. In this study, two new multi-circle detection algorithms are developed to facilitate an automatic bladder cancer diagnosis system: one is a modified circular Hough Transform algorithm integrated with edge gradient information; and the other one is a stochastic search approach based on real valued artificial immune systems. Computer simulation results show both algorithms outperform traditional methods such as the Hough Transform and the geometric feature based method, in terms of both precision …

Efficiency Performance Improvement Using Parallel Dc-Dc Converters With A Digital Controller, Daniel Forbes

Master's Theses

A system to improve efficiency performance of a DC-DC converter is simulated and built. The proposed system combines multiple DC-DC converters in parallel and implements a digital control scheme and load-share controller. A model of the system is developed in MATLAB Simulink and the model demonstrates the improved converter’s efficiency particularly at low load conditions. This simulation is then designed into a hardware system running three DC-DC converters in parallel, controlled by a microcontroller and a load-share controller. The hardware also confirms the simulation results, although some hardware refinements are evident as simulation results are superior. The system is designed …

Polar Field Oriented Control With 3rd Harmonic Injection, Martin Todd Hess

Master's Theses

Abstract

POLAR FIELD-ORIENTED CONTROL

with

3^RD HARMONIC INJECTION

Martin Todd Hess

Field Oriented Control (FOC), also known as vector control, is a widely used and well documented method for controlling Permanent-Magnet Synchronous Motors (PMSM) and induction motors. Almost invariably the orientation of the stator and rotor (field) fluxes are described in rectangular coordinates. In this thesis we explore the practicality of using polar coordinates.

Third harmonic injection is also a well-known technique that allows full utilization of the bus (DC-link), thus allowing the motor to run to full base speed without the use of field weakening. This technique potentially …