Electrical and Computer Engineering Commons^™

The Self-Heating Effects Of Bipolar Juction Transistors On The Functionality Of A Current Feedback Amplifier, Xuesong Xie

Electrical Engineering Dissertations - Archive

Self-heating effects strongly affect the performance of modern silicon-on-insulator (SOI) bipolar junction transistors. This research work does an extensive analysis of self-heating effects on large-signal behavior, small-signal behavior and transient operation of bipolar junction transistors. The two mechanisms in which device temperature affects large-signal behavior of a BJT transistor are investigated, i.e. the common-emitter (CE) configuration is to be driven by a constant base-emitter voltage and a constant base current. It is shown that the output characteristic of a BJT transistor is less sensitive to self-heating under a fixed base current than a fixed base-emitter voltage. A simple method of …

High Detectivity Pyroelectric Infrared Detector, Annand Balasubramaniyam

Electrical Engineering Theses - Archive

The sensors which measure physical quantities by sensing them as thermal quantities and then converting the thermal signals into electrical signals are called thermal sensors. One such type of thermal sensor is a pyroelectric infrared sensor. Thermal sensors are not popular mainly because they are slow devices, and they have low sensitivity when compared to photon detectors. One major advantage of thermal detectors over photon detectors is that they can operate at room temperature. This is one of the main motivations for this research. The aim of the thesis is to design an uncooled, high detectivity pyroelectric infrared detector. The …

Charge Pump Circuit, Paras Shah

Electrical Engineering Theses - Archive

The sole aim of this work is to show how to generate higher voltages greater than the power supply voltage. This idea is implemented using transistors and capacitors on silicon and is called a charge pump circuit. A charge pump circuit is implemented as a voltage doubler circuit in this work using 0.25um gate length technology. A 6-stage Dickson charge pump circuit was designed to produce a 15 V output from a 5 V supply using two phase non-overlapping clock signals that drive the charge pump. It also describes the advanced architectures with complex circuit design and dynamic techniques for …

Passive Rf Sensors And Wireless Sensor Interrogation, Srikar Deshmukh

Electrical Engineering Theses - Archive

Recently, a new type of passive sensor called the antenna sensor has been developed. The antenna sensor incorporates a patch antenna as the sensing element as well as the data transmitting element. Physical factors such as strain and ground plane crack cause the patch antenna resonant frequency to change. By measuring the change in patch antenna resonant frequency these physical factors can be quantified.Conventional resonant frequency measurement methods require a wired connection to the antenna sensor. The wireless interrogation technique eliminates this requirement while offering all the advantages that a wireless sensor interface offers over a wired sensor interface. In …

A High Fill Factor Cmos Image Sensor For Ir Camera Applications, Daniel Mcbride

Electrical Engineering Theses - Archive

In this thesis, a unit cell for high-SNR applications is presented. The proposed circuit is significantly smaller than other circuits that perform dark current subtraction because less circuitry is used inside the unit cell. The proposed circuit uses only two transistors and one resistor inside each unit cell to suppress the dark current. The size of the circuit in the layout is 25 um x 25 µm. With this new unit cell and routing approach, the size of the unit cell was reduced by 300% compared to other circuits which also suppress dark current.

Implementation Of Security Within Gen2 Protocol, Shesh Kumar Jagannatha

Electrical Engineering Theses - Archive

In this thesis, I propose and evaluate several methods to integrate security within the identification process and memory access processes of the ISO 18000-6C (or GEN2) passive UHF radio frequency identification (RFID) protocol. The RFID Tags are promiscuous and they emit their unique identifiers in clear upon interrogation from the Reader. They do not have a mutual authentication process to validate the Readers and Tags, this allows eavesdropping, illicit reading from a malicious Reader and counterfeit Tags. GEN2 Tags are being integrated into driver's licenses and being used for border crossing identities; thus, there is a need to secure both …

Modeling And Design Of Multi-Port Dc/Dc Converters, Zhijun Qian

Electronic Theses and Dissertations

In this dissertation, a new satellite platform power architecture based on paralleled three-port DC/DC converters is proposed to reduce the total satellite power system mass. Moreover, a fourport DC/DC converter is proposed for renewable energy applications where several renewable sources are employed. Compared to the traditional two-port converter, three-port or four-port converters are classified as multi-port converters. Multi-port converters have less component count and less conversion stage than the traditional power processing solution which adopts several independent two-port converters. Due to their advantages multi-port converters recently have attracted much attention in academia, resulting in many topologies for various applications. But …

High-Density And High-Efficiency Soft Switching Modular Bi-Directional Dc-Dc Converter For Hybrid Electric Vehicles, John Elmes

Electronic Theses and Dissertations

This dissertation1 presents the design of a high-density and high-efficiency soft-switching bi-directional DC-DC converter for hybrid-electric vehicles. The converter operates in a new bidirectional interleaved variable-frequency quasi-square-wave (QSW) mode, which enables high efficiency, high switching frequency, and high power-density. The converter presented utilizes a new variable frequency interleaving approach which allows for each module to operate in an interleaved position while allowing for tolerance in inductance and snubber capacitor values. The variable frequency interleaved soft-switching operation paired with a high-density nanocrystalline inductor and high-density system structure results in a very high performance converter, well exceeding that of the current technology. …

Robust Dialog Management Through A Context-Centric Architecture, Victor C. Hung

Electronic Theses and Dissertations

This dissertation presents and evaluates a method of managing spoken dialog interactions with a robust attention to fulfilling the human user’s goals in the presence of speech recognition limitations. Assistive speech-based embodied conversation agents are computer-based entities that interact with humans to help accomplish a certain task or communicate information via spoken input and output. A challenging aspect of this task involves open dialog, where the user is free to converse in an unstructured manner. With this style of input, the machine’s ability to communicate may be hindered by poor reception of utterances, caused by a user’s inadequate command of …

Query Processing In Location-Based Services, Fuyu Liu

Electronic Theses and Dissertations

With the advances in wireless communication technology and advanced positioning systems, a variety of Location-Based Services (LBS) become available to the public. Mobile users can issue location-based queries to probe their surrounding environments. One important type of query in LBS is moving monitoring queries over mobile objects. Due to the high frequency in location updates and the expensive cost of continuous query processing, server computation capacity and wireless communication bandwidth are the two limiting factors for large-scale deployment of moving object database systems. To address both of the scalability factors, distributed computing has been considered. These schemes enable moving objects …

Extreme Ultraviolet Spectral Streak Camera, John Michael Szilagyi

Electronic Theses and Dissertations

The recent development of extreme ultraviolet (EUV) sources has increased the need for diagnostic tools, and has opened up a previously limited portion of the spectrum. With ultrafast laser systems and spectroscopy moving into shorter timescales and wavelengths, the need for nanosecond scale imaging of EUV is increasing. EUV’s high absorption has limited the number of imaging options due to the many atomic resonances in this spectrum. Currently EUV is imaged with photodiodes and X-ray CCDs. However photodiodes are limited in that they can only resolve intensity with respect to time and X-ray CCDs are limited to temporal resolution in …

Design Of A Wideband Dual-Polarized Cavity Backed Slot Antenna, Rajesh Paryani

Electronic Theses and Dissertations

A new technique for designing wideband dual-polarized cavity-backed slot antennas is presented. The structure is in the form of a double-resonant, dual-polarized slot antenna backed by a shallow substrate integrated cavity with a depth of approximately one tenth the free space wavelength. The presence of the cavity behind the slot enhances the antenna's directivity and reduces the possibility of surface wave propagation in the antenna substrate when the element is used in an array environment. Moreover, the dual-polarized nature of this radiating element may be exploited to synthesize any desired polarization (vertical, horizontal, RHCP, or LHCP). The double-resonant behavior observed …

The Pdf Of Irradiance For A Free-Space Optical Communications Channel: A Physics Based Model, David Wayne

Electronic Theses and Dissertations

An accurate PDF of irradiance for a FSO channel is important when designing a laser radar, active laser imaging, or a communications system to operate over the channel. Parameters such as detector threshold level, probability of detection, mean fade time, number of fades, BER, and SNR are derived from the PDF and determine the design constraints of the receiver, transmitter, and corresponding electronics. Current PDF models of irradiance, such as the Gamma-Gamma, do not fully capture the effect of aperture averaging; a reduction in scintillation as the diameter of the collecting optic is increased. The Gamma-Gamma PDF of irradiance is …

Hurricane Wind Speed And Rain Rate Measurements Using The Airborne Hurricane Imaging Radiometer (Hirad), Ruba Amarin

Electronic Theses and Dissertations

This dissertation presents results for an end-to-end computer simulation of a new airborne microwave remote sensor, the Hurricane Imaging Radiometer, HIRAD, which will provide improved hurricane surveillance. The emphasis of this research is the retrieval of hurricane-force wind speeds in the presence of intense rain and over long atmospheric slant path lengths that are encountered across its wide swath. Brightness temperature (Tb) simulations are performed using a forward microwave radiative transfer model (RTM) that includes an ocean surface emissivity model at high wind speeds developed especially for HIRAD high incidence angle measurements and a rain model for the hurricane environment. …

Conventional And Zvt Synchronous Buck Converter Design, Analysis, And Measurement, Mark Cory

Electronic Theses and Dissertations

The role played by power converting circuits is extremely important to almost any electronic system built today. Circuits that use converters of any type depend on power that is consistent in form and reliable in order to properly function. In addition, today's demands require more efficient use of energy, from large stationary systems such as power plants all the way down to small mobile devices such as laptops and cell phones. This places a need to reduce any losses to a minimum. The power conversion circuitry in a system is a very good place to reduce a large amount of …

Single Channel Vocal Separation Using Median Filtering And Factorisation Techniques, Derry Fitzgerald, Mikel Gainza

Articles

This paper deals with the problem of the extraction of vocals from single channel audio signals containing both vocals and other instruments, including both pitched instruments and percussion instruments. A novel median filtering-based approach for the extraction of vocal tracks is described, which is simple and efficient to implement. Further improvements in separation quality are then obtained by the application of tensor factorisation techniques to further extract residual instruments from the vocal mix. Finally, a novel use of non-negative partial matrix cofactorisation is demonstrated as a means of further improving separation quality. Here the original single channel mixture is partially …

The Fractal Market Hypothesis: Applications To Financial Forecasting, Jonathan Blackledge

Books/Book chapters

No abstract provided.

Connecting Micro-Generators In Parallel To The Low Voltage Distribution Network Utilising Standard En50438 In The Republic Of Ireland, Liam Murphy

Other resources

The green agenda has been much to the fore internationally and has particularly had an influence in Republic of Ireland (ROI) where there are ‘green’ ministers in Government. Mr. Eamon Ryan who is the Minister for Communications, Energy and Natural Resources has particularly championed the idea of self generation. The author’s interest in the subject matter is to investigate the up-take of micro-generation and determine the likely short term future along with the grid tie standard i.e. EN50438.

Issues surrounding micro-generation are considered from the international and national perspective and from a customer and generation utility point of view. The …

Blind Single Channel Sound Source Separation, Mark Leddy

Masters

In recent years source separation has become an increasingly popular area of research in the signal processing community. The subject has found applications in a variety of fields such as medical imaging, sound and audio, econometrics and geophysics. This document will discuss the application of source separation techniques to the area of audio. Sound source separation is the process of observing a mixture signal made up of a number of sources, and from this mixture estimating the individual source signals. Audio source separation techniques may be crudely split into the following areas; techniques that utilise attributes of the sources, and …

Long Cavity Quantum Dot Laser Diode And Monolithic Passively Mode-Locked Operation, K Shavitranuruk

Electronic Theses and Dissertations

Advantage of the single QD active layer is its potential for very low threshold current density, which in turn can produce low internal optical loss. The low threshold current density and low internal loss thus enable a significant increase in laser diode cavity length. Because of the importance of the threshold current density in heatsinking, future technology of broad-area monolithic laser diodes can be implemented. The dissertation describes the development and the unique characteristics of single QD active layer laser with long cavity. The data are presented on single layer QD laser diodes that reach threshold current densities values of …