Engineering Commons^™

Control Design And Filtering For Wireless Networked Systems, Xiao Ma

Doctoral Dissertations

This dissertation is concerned with estimation and control over wireless networked systems. Several problems are addressed, including estimator design over packet loss links, control and estimation over cognitive radio systems, modeling and prediction of wireless sensor networks (WSNs), and localization with the Theater Positioning System (TPS). The first problem addressed is the state estimation of a discrete-time system through a packet loss link modeled by a Bernoulli random variable. The optimal filter is derived by employing exact hybrid filtering. The performance of the optimal filter is illustrated by numerical simulations. Next, we consider the problem of estimation and control over …

A Low-Power, Highly Stabilized Three-Electrode Potentiostat Using Subthreshold Techniques, Melika Roknsharifi

Doctoral Dissertations

Implantable micro- and nano- sensors and implantable microdevices (IMDs) have demonstrated potential for monitoring various physiological parameters such as glucose, lactate, CO₂ [carbon dioxide], pH, etc. Potentiostats are essential components of electrochemical sensors such as glucose monitoring devices for diabetic patients. Diabetes is a metabolic disorder associated with insufficient production or inefficient utilization of insulin. The most important role of this enzyme is to regulate the metabolic breakdown of glucose generating the necessary energy for human activities. Diabetic patients typically monitor their blood glucose levels by pricking a fingertip with a lancing device and applying the blood to a …

Techniques For Wireless Channel Modeling In Harsh Environments, Phani Teja Kuruganti

Doctoral Dissertations

With the rapid growth in the networked environments for different industrial, scientific and defense applications, there is a vital need to assure the user or application a certain level of Quality of Service (QoS). Environments like the industrial environment are particularly harsh with interference from metal structures (as found in the manufacturing sector), interference generated during wireless propagation, and multipath fading of the radio frequency (RF) signal all invite novel mitigation techniques. The challenge of achieving the benefits like improved energy efficiency using wireless is closely coupled with maintaining network QoS requirements. Assessment and management of QoS needs to occur, …

A Highly Integrated Gate Driver With 100% Duty Cycle Capability And High Output Current Drive For Wide-Bandgap Power Switches In Extreme Environments, Robert Lee Greenwell

Doctoral Dissertations

High-temperature integrated circuits fill a need in applications where there are obvious benefits to reduced thermal management or where circuitry is placed away from temperature extremes. Examples of these applications include aerospace, automotive, power generation, and well-logging. This work focuses on the automotive applications, in which the growing demand for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fuel cell vehicles (FCVs) has increased the need for high-temperature electronics that can operate at the extreme ambient temperatures that exist under the hood, which can be in excess of 150°C. Silicon carbide (SiC) and other wide-bandgap power switches that …

Optimization And Learning In Energy Efficient Cognitive Radio System, Kun Zheng

Doctoral Dissertations

Energy efficiency and spectrum efficiency are two biggest concerns for wireless communication. The constrained power supply is always a bottleneck to the modern mobility communication system. Meanwhile, spectrum resource is extremely limited but seriously underutilized.

Cognitive radio (CR) as a promising approach could alleviate the spectrum underutilization and increase the quality of service. In contrast to traditional wireless communication systems, a distinguishing feature of cognitive radio systems is that the cognitive radios, which are typically equipped with powerful computation machinery, are capable of sensing the spectrum environment and making intelligent decisions. Moreover, the cognitive radio systems differ from traditional wireless …

A Charge-Recycling Scheme And Ultra Low Voltage Self-Startup Charge Pump For Highly Energy Efficient Mixed Signal Systems-On-A-Chip, Chandradevi Ulaganathan

Doctoral Dissertations

The advent of battery operated sensor-based electronic systems has provided a pressing need to design energy-efficient, ultra-low power integrated circuits as a means to improve the battery lifetime. This dissertation describes a scheme to lower the power requirement of a digital circuit through the use of charge-recycling and dynamic supply-voltage scaling techniques. The novel charge-recycling scheme proposed in this research demonstrates the feasibility of operating digital circuits using the charge scavenged from the leakage and dynamic load currents inherent to digital design. The proposed scheme efficiently gathers the “ground-bound” charge into storage capacitor banks. This reclaimed charge is then subsequently …

Data Mining And Machine Learning Applications Of Wide-Area Measurement Data In Electric Power Systems, Penn Norris Markham

Doctoral Dissertations

Wide-area measurement systems (WAMS) are quickly becoming an important part of modern power system operation. By utilizing the Global Positioning System, WAMS offer highly accurate time-synchronized measurements that can reveal previously unobtainable insights into the grid’s status. An example WAMS is the Frequency Monitoring Network (FNET), which utilizes a large number of Internet-connected low-cost Frequency Disturbance Recorders (FDRs) that are installed at the distribution level.

The large amounts of data collected by FNET and other WAMS present unique opportunities for data mining and machine learning applications, yet these techniques have only recently been applied in this domain. The research presented …

Low Power Data Acquisition For Microimplant Biometric Monitoring Of Tremors, Tania Khanna '01

Doctoral Dissertations

In recent years, trends in the medical industry have created a growing demand for implantable medical devices. In particular, the need to provide doctors a means to continuously monitor biometrics over long time scales with increased precision is paramount to efficient healthcare. To make medical implants more attractive, there is a need to reduce their size and power consumption. Small medical implants would allow for less invasive procedures, greater comfort for patients, and increased patient compliance. Reductions in power consumption translate to longer battery life. The two primary limitations to the size of small medical implants are the batteries that …

Prognostic Approaches Using Transient Monitoring Methods, Michael Eric Sharp

Doctoral Dissertations

The utilization of steady state monitoring techniques has become an established means of providing diagnostic and prognostic information regarding both systems and equipment. However, steady state data is not the only, or in some cases, even the best source of information regarding the health and state of a system. Transient data has largely been overlooked as a source of system information due to the additional complexity in analyzing these types of signals. The development for algorithms and techniques to quickly, and intuitively develop generic quantification of deviations a transient signal towards the goal of prognostic predictions has until now, largely …

Characterization And Implementation Of An Injection Locked Frequency Divider Based On Relaxation Oscillator, Kai Zhu

Doctoral Dissertations

There has been a dramatic increase in wireless awareness among the user community in the past few years. As the wireless communication devices require more integration in terms of both hardware and software, the low-power integrated circuit (IC) solution has gained higher dedication and will dominate in the future radio-frequency IC (RFIC) design. Complementary Metal-Oxide Semiconductor (CMOS) process is extremely attractive for such applications because of its low cost and the possibility to integrate baseband and high frequency circuits on the same chip. The transceiver is often the most power-hungry block in a wireless communication system. The frequency divider (prescaler) …

A Nanostructured Fabry-Perot Interferometer For Label-Free Biodetection, Tianhua Zhang

Doctoral Dissertations

A polymer nanostructured Fabry-Perot interferometer (FPI) based biosensor has been developed, fabricated, and tested. Different from a conventional FPI, this nanostructured FPI has a layer of Au-coated nanopores inside its cavity. The Au-coated nanostructure layer offers significant enhancement of optical transducing signals due to the localized surface Plasmon resonance (L-SPR) effect. Compared to a traditional FPI for label-free biosensing applications, the polymer nanostructured FPI based biosensor offers increased sensing surface area, extended penetration depth of the excitation light, and amplification of optical transducing signals. Using a nanostructured FPI, measurements taken had great improvements in free spectral range (FSR), finesse, and …

Nanowire Giant Magnetoresistance Thin Films For Magnetic Sensors, Bryan Cox

Doctoral Dissertations

This dissertation details a novel method to fabricate magnetic sensors using nanowire giant magnetoresistance (GMR) thin films. In 1988, Albert Fert and Peter Grünberg both independently discovered a new physical phenomenon called GMR. GMR is a quantum mechanical effect found in thin film materials that are composed of alternating nanoscale ferromagnetic and non-magnetic conductive layers. When a GMR material is in the presence of a magnetic field, a change in electrical resistance is observed. The GMR effect has been utilized to produce magnetic sensors that have been used in a variety of applications, such as computer hard drive read heads, …

Development And Experimental Analysis Of Wireless High Accuracy Ultra-Wideband Localization Systems For Indoor Medical Applications, Michael Joseph Kuhn

Doctoral Dissertations

This dissertation addresses several interesting and relevant problems in the field of wireless technologies applied to medical applications and specifically problems related to ultra-wideband high accuracy localization for use in the operating room. This research is cross disciplinary in nature and fundamentally builds upon microwave engineering, software engineering, systems engineering, and biomedical engineering. A good portion of this work has been published in peer reviewed microwave engineering and biomedical engineering conferences and journals. Wireless technologies in medicine are discussed with focus on ultra-wideband positioning in orthopedic surgical navigation. Characterization of the operating room as a medium for ultra-wideband signal transmission …

Real-Time Selective Harmonic Minimization For Multilevel Inverters Using Genetic Algorithm And Artificial Neural Network Angle Generation, Faete Jacques Teixeira Filho

Doctoral Dissertations

This work approximates the selective harmonic elimination problem using Artificial Neural Networks (ANN) to generate the switching angles in an 11-level full bridge cascade inverter powered by five varying DC input sources. Each of the five full bridges of the cascade inverter was connected to a separate 195W solar panel. The angles were chosen such that the fundamental was kept constant and the low order harmonics were minimized or eliminated. A non-deterministic method is used to solve the system for the angles and to obtain the data set for the ANN training. The method also provides a set of acceptable …

Uwb Pulse Radar For Human Imaging And Doppler Detection Applications, Yazhou Wang

Doctoral Dissertations

We were motivated to develop new technologies capable of identifying human life through walls. Our goal is to pinpoint multiple people at a time, which could pay dividends during military operations, disaster rescue efforts, or assisted-living. Such system requires the combination of two features in one platform: seeing-through wall localization and vital signs Doppler detection.

Ultra-wideband (UWB) radar technology has been used due to its distinct advantages, such as ultra-low power, fine imaging resolution, good penetrating through wall characteristics, and high performance in noisy environment. Not only being widely used in imaging systems and ground penetrating detection, UWB radar also …

Low-Voltage Bulk-Driven Amplifier Design And Its Application In Implantable Biomedical Sensors, Liang Zuo

Doctoral Dissertations

The powering unit usually represents a significant component of the implantable biomedical sensor system since the integrated circuits (ICs) inside for monitoring different physiological functions consume a great amount of power. One method to reduce the volume of the powering unit is to minimize the power supply voltage of the entire system. On the other hand, with the development of the deep sub-micron CMOS technologies, the minimum channel length for a single transistor has been scaled down aggressively which facilitates the reduction of the chip area as well. Unfortunately, as an inevitable part of analytic systems, analog circuits such as …

Numerical Simulation Of Nanopulse Penetration Of Biological Matter Using The Adi-Fdtd Method, Fei Zhu

Doctoral Dissertations

Nanopulses are ultra-wide-band (UWB) electromagnetic pulses with pulse duration of only a few nanoseconds and electric field amplitudes greater than 105 V/m. They have been widely used in the development of new technologies in the field of medicine. Therefore, the study of the nanopulse bioeffects is important to ensure the appropriate application with nanopulses in biomedical and biotechnological settings. The conventional finite-difference time-domain (FDTD) method for solving Maxwell's equations has been proven to be an effective method to solve the problems related to electromagnetism. However, its application is restricted by the Courant, Friedrichs, and Lewy (CFL) stability condition that confines …

Fabrication And Characterization Of Hybrid Energy Harvesting Microdevices, Zhongcheng Gong

Doctoral Dissertations

In this dissertation, a hybrid energy harvesting system based on a lead zirconate titanate (PZT) and carbon nanotube film (CNF) cantilever structure has been designed, fabricated and studied. It has the ability to harvest light and thermal radiation energy from ambient energy and convert them to electricity.

The proposed micro-scale energy harvesting device consists of a composite cantilever beam (SU-8/CNF/Pt/PZT/Pt) which is fixed on a silicon based anchor and two electrode pads for wire bonding. The CNF acts as an antenna to receive radiation energy and convert it to heat energy and then transfer to the whole cantilever structure. The …

Basic Capillary Microfluidic Chip And Highly Sensitive Optical Detector For Point Of Care Application, Mingjin Yao

Doctoral Dissertations

A cost-effective and highly sensitive portable diagnostic device is needed to enable much more widespread monitoring of health conditions in disease prevention, detection, and control. Miniaturized and easy-to-operate devices can reduce the inherent costs and inefficiencies associated with healthcare testing in central laboratories. Hence, clinicians are beginning to use point of care (POC) testing and flexible clinical chemistry testing devices which are beneficial for the patient.

In our work, a low-cost and simple autonomous microfluidic device for biochemical detection was developed. The pumpless capillary system with capillary stop valves and trigger valves is fabricated on a silicon (Si) wafer and …

Impact Of Plug-In Hybrid Electric Vehicles On The Power Grid In A Smart Environment, Zahra Darabi

Doctoral Dissertations

This dissertation focuses on the interactions between plug-in hybrid electric vehicles (PHEVs) and the power grid. This study has used the data available through the national household travel survey (NHTS) to obtain realistic information such as the arrival time of vehicles, miles driven, and vehicles types. After data manipulation, the aggregated PHEV charging load profiles (PCLP) have been developed. The results show that the peak of PCLP overlaps with the domestic load peak. In order to alleviate this issue, several charging policies have been developed and their impacts on PCLP have been investigated. As a next contribution, the data obtained …

Design And Experimental Study Of Turbo Equalization For Multiple Antenna Systems, Amirhossein Rafati

Doctoral Dissertations

"Multiple-input multiple-output (MIMO) wireless communication systems have attracted a lot of interest in the past decade due to their capability in delivering high spectral efficiency as well as their robust performance against fading. In MIMO inter-symbol interference (lSI) channels, a severe interference problem occurs due to the lSI and co-channel interference. Thus, the error propagation problem becomes more serious, and its mitigation has to be considered when designing the receiver. In this regard, a turbo equalizer which exchanges soft information between the equalizer and the decoder has been shown to be an effective method to combat the lSI caused by …

Investigation Of Different Approaches To Combine Cable Information And Near-Field Scan Data For Radiated-Field Estimation, Keong W. Kam

Doctoral Dissertations

"Near-field scanning is often used to solve EMC problems. Aside from the purpose of visualization of near-fields, measured near-field data can be used to estimate far-field. One of many challenges associated with using near-field to far-field transform (NFFFT) technique for EMC application is the handling of attached cables. The objective of this investigation is to evaluate different methods to add cable information to the near-field data for far-field estimation. The investigation is carried out using numerical experiments in EMCoS EMC studio, which is a commercial MoM (Method of Moment) tool for EM simulation. Measurement results from a test structure are …

Identification And Visualization Of Electromagnetic Coupling Paths & Nonlinear Capacitors For Esd Protection, Hongyu Li

Doctoral Dissertations

"The first topic of this dissertation focuses on developing methods to identify and visualize electromagnetic coupling paths. The basis of the approach is to utilize an analogy between electromagnetic energy flow and fluid flow. This allows one to apply the theories and algorithms of fluid dynamics to electromagnetics and thereby to visualize the electromagnetic energy flow. This in turn can be utilized to identify the electromagnetic coupling path.

The second topic of this dissertation investigates the nonlinearity of capacitors and suggests improved trade-off between electrostatic discharge (ESD) protection and data bandwidth by using the antiferroelectric (AFE) capacitors as ESD protection. …

Low-Complexity Soft-Decision Feedback Turbo Equalization For Multilevel Modulations, Huang Lou

Doctoral Dissertations

"This dissertation proposes two new decision feedback equalization schemes suitable for multilevel modulation systems employing turbo equalization. One is soft-decision feedback equalization (SDFE) that takes into account the reliability of both soft a priori information and soft decisions of the data symbols. The proposed SDFE exhibits lower signal to noise ratio (SNR) threshold that is required for "water fall" bit error rate (BER) and much faster convergence than the near-optimal exact minimum mean square error linear equalizer (Exact-MMSE-LE) for high-order constellation modulations. The proposed SDFE also offers a low computational complexity compared to the Exact-MMSE-LE. The drawback of the SDFE …

Lyapunov Based Optimal Control Of A Class Of Nonlinear Systems, Hassan Zargarzadeh

Doctoral Dissertations

"Optimal control of nonlinear systems is in fact difficult since it requires the solution to the Hamilton-Jacobi-Bellman (HJB) equation which has no closed-form solution. In contrast to offline and/or online iterative schemes for optimal control, this dissertation in the form of five papers focuses on the design of iteration free, online optimal adaptive controllers for nonlinear discrete and continuous-time systems whose dynamics are completely or partially unknown even when the states not measurable. Thus, in Paper I, motivated by homogeneous charge compression ignition (HCCI) engine dynamics, a neural network-based infinite horizon robust optimal controller is introduced for uncertain nonaffine nonlinear …

Stochastic Optimal Adaptive Controller And Communication Protocol Design For Networked Control Systems, Hao Xu

Doctoral Dissertations

"Networked Control System (NCS) is a recent topic of research wherein the feedback control loops are closed through a real-time communication network. Many design challenges surface in such systems due to network imperfections such as random delays, packet losses, quantization effects and so on. Since existing control techniques are unsuitable for such systems, in this dissertation, a suite of novel stochastic optimal adaptive design methodologies is undertaken for both linear and nonlinear NCS in presence of uncertain system dynamics and unknown network imperfections such as network-induced delays and packet losses. The design is introduced in five papers.

In Paper 1, …

Modeling Aperture Radiation For Rf Interference Applications, Liehui Ren

Doctoral Dissertations

"The first topic proposes a rigorous method of moments(MoM) solution to evaluate the shielding effectiveness of a metallic enclosure with apertures on top wall by formulating a pair of coupled mixed potential integral equations (MPIEs). Application of Ewald transform to the computation of Green's function in the cavity yields fast convergence of series summation. Good agreements with a commercial tool, EMC studio, have proved the effectiveness of the proposed approach.

The second topic deals with prediction of electromagnetic interference radiation from components or interconnects in a printed circuit board by using convolution of the half-space Green's functions and the equivalent …

Modeling Multi-Layer Via Structure Using Peec Method, Hanfeng Wang

Doctoral Dissertations

"In this dissertation, a new integral equation formulation for via structures is developed for the capacitance extraction between vias and planes. The proposed method can be used to calculate the shared-antipad via structure which is widely used in highspeed differential signal interconnects. In addition, we use the image theory to handle inhomogeneous media. Further, a new technique is given to reduce computational resources for via-to-plane structures based on properties of the matrix coefficient. The extracted capacitance is also incorporated into the physics-based circuit model to characterize the overall performance of the via transition. In the second paper, a rigorous modeling …

Data Fusion By Using Machine Learning And Computational Intelligence Techniques For Medical Image Analysis And Classification, Beibei Cheng

Doctoral Dissertations

"Data fusion is the process of integrating information from multiple sources to produce specific, comprehensive, unified data about an entity. Data fusion is categorized as low level, feature level and decision level. This research is focused on both investigating and developing feature- and decision-level data fusion for automated image analysis and classification. The common procedure for solving these problems can be described as: 1) process image for region of interest' detection, 2) extract features from the region of interest and 3) create learning model based on the feature data. Image processing techniques were performed using edge detection, a histogram threshold …

Addressing Control And Capacitor Voltage Regulation Challenges In Multilevel Power Electronic Converters, Hossein Sepahvand

Doctoral Dissertations

Multilevel power electronic converters are the current industry solutions for applications that demand medium voltage, reasonable efficiency, and high power quality. The proper operation of these types of power converters requires special control, modulation methods, and capacitor voltage regulation techniques. Both developing capacitor voltage regulation methods and addressing their associated issues with such fall within the primary focus of this dissertation. In this dissertation an investigation was conducted on the capacitor voltage regulation constraints in cascaded H-bridge multilevel converters with a staircase output voltage waveform. In the proposed method, the harmonic elimination technique is used to determine the switching angles. …