Electrical and Electronics Commons^™

Micro Electromechanical Relays And Their Application In Variable Inductor Networks, Shifang Zhou

Dissertations

A family of microrelay devices together with integrated inductor networks has been designed, simulated, fabricated and experimental characterized. These switched networks utilize microelectromechanical systems (MEMS) as a fabrication technology and take advantage of the economies of semiconductor cleanroom batch-processing.

A new type of microrelay has been developed using a suspended TaSi₂/SiO₂ bimorph cantilever beam, gold-to-gold electrical contact, aluminum as sacrificial layer, and a combined thermal and electrostatic means of actuation. For the first time a micro variable inductor network which is digitally controlled by microrelays has been demonstrated. A test structure for electrical micro contact characterization has …

Investigation Of Optical Properties Of Inp, Ain And Sapphire For Applications In Non-Contact Semiconductor Process Monitoring, Rajasekhar Velagapudi

Theses

The objective of this thesis was to develop a reliable multi-wavelength pyrometer for simultaneous measurement of the wafer temperature and its optical properties in the wavelength range of 1 to 20 microns and temperature range of 30 to 1500° C. The spectral emissometer has been utilized for measurement of the temperature dependent optical properties of InP, AlN and Sapphire. The experimental results presented in this thesis showed that the measurement of high temperature optical properties could be performed reliably with a novel approach using the spectral ernissometer. The temperature determination capability of the emissometer was tested and verified using a …

Performance Enhancement Of Linear Robotic Workcell Using Dsp Based Control, Kedar Arvind Godbole

Theses

Robotic Controllers have for the major part been computer implementations of PID or similar controllers. In this thesis DSP based control of a Robotic Workcell is presented. The control algorithms used with the DSP based controller are Input Shaping and also State Feedback. Input Shaping is a Feed Forward strategy for eliminating vibration under certain conditions. In this thesis Input Shaping is applied to the performance enhancement of a linear robot system. Although feedback control strategies offer higher accuracy and are much more robust, feedforward strategies offer possibilities for improving the response time. Input Shaping is successfully applied to the …

A Design-For Retirement Rating Model For Environmentally Conscious Products, Xin He

Theses

Design-For-Retirement is a concept that allows one to design a product such that its retirement time and post-life treatment are optimized to lead to the minimum environmental impact and maximum financial gain. Retired product parts or subassemblies face three primary multi-lifecycle engineering treatments. The first one is to recondition them for reuse in the next lifecycle. The second one is to convert their post life parts into a material form for recycling back into new parts. The last is to dump or landfill them. Each option has a significantly different environmental cost-benefit ratio. Another important concern is the dismantling process …

Signal Processing Topics In Multicarrier Modulation : Frequency Offset Correction For Ofdm And Multiuser Interference Cancellation For Mc-Cdma, Pingping Zong

Theses

Orthogonal frequency division multiplexing (OFDM) is discussed as a special form of multi-carrier modulation (MCM). One major problem of the OFDM system is the sensitivity to an unknown frequency offset at the receiver. To improve the performance of the OFDM system, correction of the frequency offset is required before decision making. An adaptive method of frequency offset correction is presented. The adaptation algorithm used here is based on the LMS and the estimation is proven unbiased. A multiuser communications system having similar signal structure to the OFDM system, termed as multi-carrier code division multiple access (MC-CDMA), is discussed. The MC-CDMA …

Microstrip Zero-Sum Antenna; Cad And Experimental Study, Tuan H. Lam

Theses

A microstrip antenna array consisting of two elements combined with a stripline hybrid (rat-race) ring coupler is used to implement a zero-sum antenna. Numerical optimization of individual antenna elements in terms of feed location and patch size was achieved using IE3D (Zeland Software Inc., Fremont, CA), a fullwave 3-D planar electromagnetic simulation software. Further, design of a hybrid (rat-race) ring coupler in a stripline environment was carried out, yielding the sum and difference functions as 0.5 dB and 40 dB, respectively. A combination of a two-element antenna array and a hybrid (rat-race) ring coupler as a zero sum antenna has …

Design, Simulation, Fabrication And Testing Of Microprobes For A New Mems Wafer Probe Card, Yanwei Zhang

Dissertations

A new type of MEMS cantilever wafer probe card consists of an array of microcantilevers individually actuated by bimorph heating to make contact with the test chip was designed and fabricated. This probe card is called the CHIPP (Conformable, High-Pin count, Programmable ) card and can be designed to contact up to 800 I/O pads along the perimeter of a 1 cm² chip with a microprobe repeat distance of ~50 µm. Each microcantilever had an internal heater and a separate electrode carrying the signal under test and contained four separate layers plus a fifth material for the contact tip …

Design Fabrication And Characterization Of High Performance In Gaas/Inp Focal Plane Array In The 1-2.6 Μm Wavelength Region, Krishna R. Linga

Dissertations

This research thesis describes a new In_xGa_1-xAs/InA_ysP_1-y/InP technology for long wavelength photodetectors and photodetector arrays. A unique and novel detector structure was designed and fabricated using Hydride Vapor Phase Epitaxy, for low leakage current photodetector arrays in the 1-2.6 µm wavelength region. Potential applications of InGaAs focal plane arrays include near-infrared spectroscopy, fluorescence, remote sensing, environmental sensing, space and astronomical applications. The unique design concepts included the step grading of InAsP layers, lower lattice mismatch between the two InAsP graded layers, lattice matched InAsP cap layer and InGaAs absorption layer, sulphur doping …

The Design And Fabrication Of A Thermal Microprobe Integrated On An Atomic Force Microscope Probe Tip, Yongxia Zhang

Dissertations

A thermal microprobe has been designed and built for high resolution temperature sensing. The thermal microprobe consists of a very-thin-film thermocouple junction confined to the very end of a low mass Atomic Force Microscope (AFM) probe tip. Essential to high resolution temperature sensing is the confinement of the thermocouple junction to a short distance at the AFM tip. This confinement is achieved by controlled photoresist coating.

Experimental prototypes have been made with the junction confined to within 0.3 µm of the tip. The couple is made of Au/Pd, and the two metals are electrically separated elsewhere by a thin insulating …

Adaptive Space-Time Processing For Digital Mobile Radio Communication Systems, Amit Shah

Dissertations

The performance of digital mobile radio communication systems is primarily limited by cochannel interference and multipath fading. Antenna arrays, with optimum combining (OC), have been shown to combat multipath fading of the desired signal and are capable of reducing the power of interfering signals at the receiver through spatial filtering. With OC, the signals received by several antenna elements are weighted and combined to maximize the output signal-to-interference-plus-noise ratio (SLNR). We derive new closed-form expressions for (1) the probability density function (PDF) of the SINR at the output of the optimum combiner, (2) the average probability of bit error rate …

Multi-Wavelength Pyrometric Systems For Emissivity-Independent Non-Contact Temperature Sensing, Michael B. Kaplinsky

Dissertations

A Multi-Wavelength Imaging Pyrometer (M-WIP) for real-time remote sensing of temperature profiles of targets with unknown emissivity was developed and demonstrated. To measure the spectral radiance of a target at several distinct wavelengths an M-WIP system was implemented based on an 320x122-element PtSi IR-CCD imager with an assembly of 7 narrow-band 1k filters in the range from 1790nm to 4536nm. A real-time algorithm for simultaneous estimation of the temperature and model parameters of the target emissivity from the least-squares fit of the theoretical model of 1k camera output signal to the experimental spectral measurements was developed and implemented. This rea1-time …

Development Of A Mathematical Model Of Gait Dynamics, Tae Ho Choi

Dissertations

There exists hypothesis that gait selection is strongly correlated with mechanical energy efficiency in normal subjects. The hypothesis is experimentally proven, and intuitively taken for granted. However, it is not mathematically proven that the minimum energy consumption hypothesis is the underlying principle for the normal human gait. To prove the hypothesis we have developed a mathematical model of human walking, in which it is possible to predict an optimal gait at any given speed of walking based on the principle of minimum mechanical energy consumption.

This improved model, which includes the double-support phase of walking as well as the swing …

Performance Optimization Of Very High Frame Rate Ccd Burst-Image Sensors, Zeynep M. Pektas

Dissertations

The primary objective of this work was to demonstrate the feasibility of an image sensor that is capable of capturing images at 10⁷ frames per second. Such high frame rate operation is based on storage of a certain (N) number of frames into the BCCD memory registers and readout at a slower rate at the end of the frame collection period. To accommodate an optical frame time of 100ns, a high-speed virtual-gate photodetector with six multiple n-type implants was proposed and a novel design strategy was developed. The feasibility of this design was demonstrated by simulating the entire photodetector …

Analysis And Comparison Of Resistive, Ferroelectric And Pyroelectric Uncooled Bolometers For Electronic Imaging Systems, Mo-Huang Li

Theses

The performance parameters (responsivity (R_v). detectivity (D*), total noise and response time) of resistive, pyroelectric and ferroelectric bolometer detectors are dependent on a large number of key variables including chopping frequercy, the input impedance and voltage noise of the readout circuitry, the structure dependent parameters (particularly thermal conductance and thermal capacitance), and material properties such as dielectric constant, pyroelectric coefficient, loss tangent and thin film thickness. The interrelationship between the key variables and their influence on performance is often complex and not easily discerned for the three major types of thermal detectors: resistive, pyroelectric and ferroelectric bolometers.

In …

Analysis Of 320x240 Uncooled Microbolometer Focal Plane Array And Design Of Thermoelectric Cooler Controller, Takayoshi Fukaya

Theses

Uncooled microbolometer focal plane array is one of the promising method used in uncooled infrared imaging projects. The array's advantages over the conventional cooled imagers are its ability to operate without cryogenic cooler or dewar and its low cost. For the past several years, the ULTRA (Uncooled, Low cost, Technology Reinvestment Alliance) Consortium has been developing uncooled microbolometer imaging system.

This thesis investigates the technology behind the ULTRA camera system. The theoretical as well as the operation of the uncooled microbolometer focal plane array and the processing hardware and software is analyzed and explained.

Thermoelectric cooler controller for the microbolometer …

Low Frequency Characterization Of A Loop Antenna, Irene Koukhta

Theses

The conventional solution of an integral equation for the loop antenna in free space can be expressed analytically using Fourier Series. However, the solutions based on delta gap feed model yield divergent input susceptance.

To overcome such diverging results, alternative solution using equivalent magnetic frill current feed models were implemented. Although low frequency models for delta gap feeds were suggested, no generalized low frequency expansions for the input admittance have been reported previously. In this work, such generalized low frequency expansion are developed for both delta-gap and magnetic frill feeds of loop antennas. Validity of such expansion have been investigated …

Petri Net Modeling And Performance Analysis Of Z39.50 Search And Retrieval Protocol, Roopali Paranjpe

Theses

Z39.50 is an American Standard for information retrieval. The standard depicts a client-server model of computing. With reference to the Open System Interconnection (COSI)) model developed by International Standards Organization (ISO); Z39.50 is an application layer protocol. A Z39.50 client performs searching, querying and requesting functions and a Z39.50 server interfaces with the database in the remote system and responds to client requests by providing a set of records for the search query.

Z39.50 state tables describe a complex set of concurrent and serial events. A Petri net model is prepared for the entire system comprising the protocol. A Petri …

Adaptive Distributed Detection With Applications To Cellular Cdma, Jian-Guo Chen

Dissertations

Chair and Varshney have derived an optimal rule for fusing decisions based on the Bayesian criterion. To implement the rule, probabilities of detection P_D and false alarm P_F for each detector must be known, which is not readily available in practice. This dissertation presents an adaptive fusion model which estimates the P_D and P_F adaptively by a simple counting process. Since reference signals are not given, the decision of a local detector is arbitrated by the fused decision of all the other local detectors. Adaptive algorithms for both equal probable and unequal probable sources, for independent …

Synthesis And Characterization Of Lpcvd Sic Films Using Novel Precursors, Mahalingam Bhaskaran

Dissertations

A unique low pressure chemical vapor deposition (LPCVD) process has been developed to synthesize amorphous and crystalline SiC films using environmentally benign chemicals. The interrelationships governing the process variables, compositions and select properties of the resulting films were established. Such films can be used to produce high quality mask membrane for x-ray lithography. These films can also be used in fabricating high power electrical devices, and hetrojunction devices in conjunction with silicon.

Amorphous SiC films were synthesized using a single precursor, ditertiarybutylsilane, at temperatures below 850°C. Compositional analysis performed on these deposits revealed that, in the deposition temperature range of …

Bilinear Time-Frequency Representations Of Heart Rate Variability And Respiration During Stress, Rindala Saliba

Dissertations

Recently, joint time-frequency signal representation has received considerable attention as a powerful tool for analyzing a variety of signals and systems. In particular, if the frequency content is time varying as in signals of biological origin which often do not comply with the stationarity assumptions, then this approach is quite attractive. In this dissertation, we explore the possibility of better representation of two particular biological signals, namely heart rate variability (HRV) and respiration. We propose the use of time-frequency analysis as a new and innovative approach to examine the physical and mental exertion attributed to exercise. Two studies are used …

Two Dimensional Agonistic Control, Daqing Yang

Dissertations

The conventional method of precise multiple-axis motion control entails use of a multiple axis positioning system with each axis carrying not only the workpiece but also the positioning system of the remaining axes. The resultant structure is heavy, sluggish, and expensive. An alternative positioning technique is being investigated in which the motion of the workpiece is controlled by pulling it with tendons, each of which has its own actuator. Since the actuators can be mounted on the base of the structure instead of being carried by motion system of the other axes, they can be relatively large and powerful without …

Counterpulsation Cardiac Assist Device Controller Defection Filter Simulation And Canine Experiments, Carl Edward Werner

Dissertations

Electronic control systems for counterpulsation Cardiac Assist Devices (CADs) are an essential part of cardiac assistance. Synchronization of the counterpulsation CAD controller with the cardiac cycle is critical to the efficacy of the CAD. The robustness of counterpulsation CAD controllers varies with the ability of the CAD controller to properly trigger on aortic pressure (Pa) and electrocardiogram (ECG) signals for sinusoid rhythms, non-sinusoid rhythms and non-ideal signals resulting from surgical intervention. An analog-to-digital converter and digital-to-analog converter based CAD controller development platform was devised on a 33Mhz PC-AT.

Counterpulsation Pa systolic rise and dicrotic notch detectors were demonstrated with a …

Tcp/Ip Traffic Over Atm Network With Abr Flow And Congestion Control, Liping An

Theses

Most traffics over the existing ATM network are generated by applications running over TCP/IP protocol stack. In the near future, the success of ATM technology will depend largely on how well it supports the huge legacy of existing TCP/IP applications.

In this thesis, we study and compare the performance of TCP/IP traffic running on different rate based ABR flow control algorithms such as EFCI, ERICA and FMMRA by extensive simulations. Infinite source-end traffic behavior is chosen to represent, FTP application running on TCP/IP. Background VBR traffic with different ON-OFF frequency is introduced to produce transient network states as well as …

Performance Evaluation Of Cebus Power Line Communication In The Presence Of X-10 Module Signaling, Nashwa F. Kamel

Theses

A power line of CEBus has great potential towards inexpensive home automation. Both PLBus and X-10 uses [sic] burst of 120KHz signals to transmit bits of information on the power line. However, these two systems are completely incompatible and can conflict with each other. This thesis presents the first performance evaluation of Power Line CEBus communication in the presence of X-10 module signaling. The evaluation included simulation experiments measuring packet delays, message delays, message throughput, channel throughput and the percentage of messages received in error verses [sic] different loads. Network performance has been confirmed to function well in terms of …

A Cost Model For Multi-Lifecycle Engineering Design, Bin Zhang

Theses

Design for Environment aims to yield a product whose aggregate environmental impact is as small as possible. This thesis characterizes a product recovery system and defines the concepts of product lifetime and part lifetime. A multi-lifecycle product recovery model is developed based on the concepts of product tree and disassembly path representation, four product recovery choices, time varying costs, cost comparison. The four product recovery choices of a part in the product tree are: Reconditioning, Part Remanufacturing, Material Recycling, and Landfill. This thesis focuses on how to improve the product design while minimizing environmental impact of the product and introduces …

Vibration Control Of Robotic Modules Using Input Shaping Algorithm, Murat Eren

Theses

In this thesis, vibration control using input shaping algorithm is studied. Vibration Control of flexible structures is an important problem and has been an active research area. Different approaches have been developed for vibration control which can be divided roughly into feedback and feedforward methods. Feedback methods need measurements and on-line calculation of the controller outputs. Although feedback methods are generally more robust and have a number of well known performance advantages, proper use of feedforward control can also significantly improve the speed of response of the system.

Input shaping is one of these feedforward methods. It has been successfully …

Motion Estimation And Video Coding, Xiaochun Xia

Dissertations

Over the last ten years. research on the analysis of visual motion has come to play a key role in the fields of data compression for visual communication as well as computer vision. Enormous efforts have been made on the design of various motion estimation algorithms.

One of the fundamental tasks in motion estimation is the accurate measurement of 2-D dense motion fields. For this purpose. we devise and present in this dissertation a multiattribute feedback computational framework. In this framework for each pixel in an image. instead of a single image intensity. multiple image attributes are computed as conservation …

Scheduling And Discrete Event Control Of Flexible Manufacturing Systems Based On Petri Nets, Huanxin Henry Xiong

Dissertations

A flexible manufacturing system (FMS) is a computerized production system that can simultaneously manufacture multiple types of products using various resources such as robots and multi-purpose machines. The central problems associated with design of flexible manufacturing systems are related to process planning, scheduling, coordination control, and monitoring. Many methods exist for scheduling and control of flexible manufacturing systems, although very few methods have addressed the complexity of whole FMS operations. This thesis presents a Petri net based method for deadlock-free scheduling and discrete event control of flexible manufacturing systems. A significant advantage of Petri net based methods is their powerful …

Real-Time Implementation Of An Adaptive Control System For A 3-Zone Rapid Thermal Processing Station, David Hur

Theses

In this thesis, the implementation details of a real time adaptive control system for a TI 3-zone RTP station, as well as the simulation and the experimental results are presented. Extensive simulation of the system is performed in order to ensure proper operation of the system. The experimental results are used to verify proper operation of the closed loop control system. Initial experiments were conducted using two thermocouples. Further experiments were conducted using one thermocouple for the purpose of testing the performance of the system using Extended Kalman Filter as the state estimator.

The implementation of the control system is …

Residual Stress Analysis Of Sputtered Tantalum Silicide Thin Film, Young Joo Song

Theses

The influence of different argon pressures on the residual stress, microstructure, and resisitivity of sputtered tantalum silicide thin films has been investigated. TaSi₂ films were deposited onto Si wafers by dc magnetron sputtering. The deposition temperature was assumed to be 300°C. The thickness was about 0.5 μm. The residual stresses in the films deposited at different argon pressures were determined by curvature measurement method. The compressive intrinsic stress of 1033.4MPa was measured at P_Ar = 0.5 mTorr. The intrinsic stress in the films seemed to change from compression to tension as P_Ar increased above 8mTorr. A maximum …