ECE Department Calendar

May
6
Tue
Defense: Schlitt
May 6 @ 9:00 pm – 11:00 pm

UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT

THESIS DEFENSE FOR THE DEGREE OF
MASTER OF SCIENCE

by

Lawrence Schlitt
Advisor: Priyank Kalla

THERMAL CHARACTERIZATION ABSTRACTION FOR INTEGRATED OPTOELECTRONICS

Advances in Silicon Photonics are enabling hybrid integration of optoelectronic circuits alongside current CMOS technologies. To fully exploit the capability of this integration, it is important to explore the effects of thermal gradients on optoelectronic devices. The sensitivity of optical components to temperature variation gives rise to design issues in SOI optoelectronic technology. The thermo-electric effect becomes problematic with the integration of hybrid optoelectronic systems, where heat is generated from electrical components. Through the thermo-optic effect the optical signals are in turn effected and compensation is necessary. To improve the capability of optical SOI designs, optical-wave-simulation models and the characteristic thermal operating environment need to be integrated to ensure proper operation.

In order to exploit the potential for compensation by virtue of resynthesis, temperature characterization on a system level is required. Thermal characterization within the flow of physical design automation tools for hybrid optoelectronic technology enables device resynthesis and validation at a system level. Additionally, thermally-aware routing and placement would be possible. A simplified abstraction will help in the active design process, with the contemporary CAD flow when designing optoelectronic features.

This thesis investigates an abstraction model to characterize the effect of a temperature gradient on optoelectronic circuit operation. To make the approach scalable, reduced order computations are desired the effectively model the effect of temperature on an optoelectronic layout, this is achieved using an electrical analogy to heat flow. Given an optoelectronic circuit and using a thermal resistance network to abstract thermal flow, we compute the temperature distribution throughout the layout. Subsequently, we show how this thermal distribution across the optoelectronic system layout can be integrated with optoelectronic device and system level analysis tools. Validation of the model is performed by comparing the abstract computation to that of full-scale simulations.


Tuesday, May 6, 2014
3:00 p.m.
ECE Conference Room
3235 MEB

The public is invited

Jun
2
Mon
Defense: H. Pourzand
Jun 2 @ 12:00 pm – 2:00 pm

UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT

THESIS DEFENSE FOR THE DEGREE OF
MASTER OF SCIENCE

by

Hoorad Pourzand
Advisor: Massood Tabib-Azar


Microelectromechanical gyroscopes are readily used in cars and cell phones. Tactical gyroscopes are readily available inexpensively and they offer 0.01 to 0. 1 percent scale factor in accuracy. On the other hand, strategic gyroscopes with much better performance are 100,000 more expensive. The main objective of this work is to explore the possibility of developing in-expensive strategic grades gyroscopes using MEMS.

Most of the available gyroscopes are surface micro machined due to fabrication issues and misalignment problems that are involved in multistep fabrication processes necessary to use the bulk of the wafer as the proof mass in the MEMS gyroscope. It can be shown that the sensitivity of the gyroscope is inversely proportional to the natural frequency; so if bulk micromachining technique is used it is possible to decrease the natural frequency further than current limits in order to increase sensitivity. This thesis is focused on proposing a way to use bulk of the silicon wafer in the gyroscope to decrease the natural frequency to very low levels such as sub kilohertz regime that cannot be achieved by single mask surface micromachining processes and then proposing a solution for solving the misalignment problem caused by using multiple fabrication steps and masks instead of using only one mask in surface micro machined gyroscopes.

In our design discrete proofmasses are linked together around a circle by compliant structures to insure highest effective mass and lowest effective spring constant. By using a proposed double sided fabrication technology the effect of misalignments on frequency mismatch can be reduced. ANSYS simulations show that 20 µm misalignment between the masks causes a frequency shift equal to 0.3% of the natural frequency, that can be compensated using electrostatic frequency tuning. Acceleration parasitic effects can also be a major problem in a low natural frequency gyroscope. In our design a multiple sensing electrode configuration is used that cancels the acceleration effects completely. The sensitivity of the gyroscope with 3126 Hz natural frequency is simulated to be 574 mV/(Deg/sec) or about four times higher than 132 mV/(Deg/sec) , which was used as a benchmark for a sensitive gyroscope.


Monday, June 2, 2014
12:00 p.m.
2610 SMBB

The public is invited

Jun
3
Tue
Defense: Seyedhosseini
Jun 3 @ 10:00 am – 12:00 pm

UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT

DISSERTATION DEFENSE FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

by

Mojtaba Seyedhosseini
Advisor: Tolga Tasdizen

Scene Labeling with Supervised Contextual Models

Scene labeling is the problem of assigning an object label to each pixel of a given image. It is the primary step towards image understanding and unifies object recognition and image segmentation in a single framework. A perfect scene labeling framework detects and densely labels every region and every object that exists in an image. This task is of substantial importance in a wide range of applications in computer vision. Contextual information plays an important role in scene labeling frameworks. A contextual model utilizes the relationships among the objects in a scene to facilitate object detection and image segmentation. Using contextual information in an effective way is one of the main questions that should be answered in any scene labeling framework.

In this dissertation, we develop two scene labeling frameworks that rely heavily on contextual information to improve the performance over state-of-the-art methods. The first model, called the multi-class multi-scale contextual model (MCMS), uses contextual information from multiple objects and at different scales for learning discriminative models in a supervised setting. The MCMS model incorporates cross-object and interobject information into one probabilistic framework and thus is able to capture geometrical relationships and dependencies among multiple objects in addition to local information from each single object present in an image. The second model, called the contextual hierarchical model (CHM), learns contextual information in a hierarchy for scene labeling. At each level of the hierarchy, a classifier is trained based on downsampled input images and outputs of previous levels. The CHM then incorporates the resulting multi-resolution contextual information into a classifier to segment the input image at original resolution. This training strategy allows for optimization of a joint posterior probability at multiple resolutions through the hierarchy. We demonstrate the performance of CHM on different challenging tasks such as outdoor scene labeling and edge detection in natural images and membrane detection in electron microscopy images.

We also introduce two novel classification methods. WNS-AdaBoost speeds up the training of AdaBoost by providing a compact representation of a training set. Disjunctive normal random forest (DNRF) is an ensemble method that is able to learn complex decision boundaries and achieves low generalization error by optimizing a single objective function for each weak classifier in the ensemble.

Finally, a segmentation framework is introduced that exploits both shape information and regional statistics to segment irregularly shaped intracellular structures such as mitochondria in electron microscopy images.

Tuesday, June 3, 2014
10:00 a.m.
Evans Conference Room
3780 WEB (3rd floor)

The public is invited

Jun
4
Wed
ECE Seminar – Control and Diagnosis of Discrete Event Systems: Some Recent Trends @ Warnock (WEB) 1250
Jun 4 @ 3:00 pm – 4:00 pm
ECE Seminar - Control and Diagnosis of Discrete Event Systems:  Some Recent Trends @ Warnock (WEB) 1250

Stephane Lafortune

University of Michigan-Ann Arbor

When: Wednesday, June 4, 2014 at 3:00 p.m.
Where: Warnock 1250

Abstract

We will present an overview of recent research trends in control and diagnosis of Discrete Event Systems (DES) that are motivated by challenges arising in cyber-physical systems.

In the first part of the talk, we will review the basic theory of supervisory control of DES, discuss its connection with reactive synthesis in computer science, and present results on its application to the problem of collision avoidance in vehicular networks. In this application, the continuous dynamics of the vehicles are abstracted in a discrete-event model, where uncontrollable events capture unmodeled dynamics and unobservable events capture measurement uncertainty.

In the second part of the talk, we will review the basic theory of fault diagnosis in partially-observed DES and then discuss recent work on enforcement of opacity, a class of properties studied in computer security. Opacity is essentially the dual of diagnosability. We will discuss how opacity enforcement techniques can be used to protect users’ privacy in location-based services.

Speaker Biographies

Stéphane Lafortune is a Professor in the Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor. He obtained his degrees from Ecole Polytechnique de Montréal (B.Eng), McGill University (M.Eng), and the University of California at Berkeley (PhD), all in electrical engineering. Dr. Lafortune is a Fellow of the IEEE (1999). His research interests are in discrete event systems and include multiple problem domains: modeling, diagnosis, control, optimization, and applications to computer systems. He co-authored, with C. Cassandras, the textbook Introduction to Discrete Event Systems (2nd Edition, Springer, 2008). He is co-developer of the software packages DESUMA and UMDES.

Jul
17
Thu
Defense: Bhola
Jul 17 @ 2:00 pm – 4:00 pm

UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT

THESIS DEFENSE FOR THE DEGREE OF
MASTER OF SCIENCE

by

Vishal Bhola
Advisor: Prashant Tathireddy

 

Inkjet Printing of Smart Hydrogels and their Response Characterization

Hydrogels find extensive applications in biomedical research, process control in bioreactors and metabolite monitoring in human/ animal research. However, for commercial success of hydrogel based products there needs to be an easy technique or process to dispense pre-polymerized hydrogel in a precise location, in precise microliter volumes. Moreover, the process should be inexpensive as well as repeatable. Dispensing microliter volumes is important because smaller the volume the faster the sensor response. There exists no technique at present that can produce these hydrogels with micro-scale precision commercially for these applications. In this project, we present the use of inkjet printing process for inexpensive, highly repeatable micro-scale patterning for synthesis of smart hydrogel arrays for various applications with a potential for commercial scale synthesis.

Thursday, July 17, 2014
2:00 p.m.
4100 SMBB

The public is invited

Jul
18
Fri
Defense: Paulsen
Jul 18 @ 1:00 pm – 3:00 pm

UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT

DISSERTATION DEFENSE FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

by

Andrew Paulsen
Advisor: Ajay Nahata

Design Techniques for Terahertz Plasmonic Filters

Wireless communication systems in the terahertz (THz) frequency range promise to dramatically increase available bandwidth in the electromagnetic spectrum. These wireless systems will require filtering techniques capable of operating in this relatively unused part of the spectrum. In pushing towards more advanced filtering techniques, we demonstrate a terahertz filter design methodology based upon k-space that shows more complex filters; such as band-pass, comb-pass and polarization dependent filters. Using this design flow we demonstrate: setting the center frequency and bandwidth in THz band-pass filters, controlling the individual magnitudes of each resonant peak in a comb filter, adjusting the transmittance of a filter at two different frequencies by spatially rotating the filter, and varying the transmittance at a single frequency by changing the polarization angle of incoming radiation. We believe this new k-space filter design methodology will help to create more complex filters that will find application in wireless THz communication systems.


Friday, July 18, 2014
1:00 p.m.
ECE Conference Room
3235 MEB

The public is invited

Aug
6
Wed
Defense: Novak
Aug 6 @ 9:00 am – 11:00 am

UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT

DISSERTATION DEFENSE FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

by

Ondrej Novak
Advisor: Richard Brown

RF-Powered Mixed-Signal Microcontroller with Wireless Ultra Wideband Transmitter for Electrochemistry and Bio-Sensing

Miniature electronic microsystems have become a powerful enabling tool for advanced biomedical research. The diversity of biomedical research dictates that microsystems must be developed and customized specifically for each new application. For advanced long-term experiments on animals, a custom designed system-on-chip (SoC) is usually necessary to meet desired specifications. Custom SoCs, however, are often prohibitively expensive, preventing many new ideas from being explored.

We have developed a single-chip integrated microsystem that offers the most commonly used sensor interfaces, high computational power, and which requires minimum external components to operate. Included peripherals can also drive electrolysis or redox reactions. The SoC is highly modular and well suited for prototyping in- and ex-vivo experimental devices, eliminating the high cost of SoC development for each new application.

Additionally, the system includes a wireless ultra-wide band (UWB) transmitter. An investigation of the suitability of the UWB technology for neural recording systems is presented. Experimental data capturing the UWB signal transmission through an animal head is presented and a statistical model for large-scale signal fading is developed.

Wednesday, August 6, 2014
9:00 a.m.
Eccles Boardroom
Warnock Engineering Bldg (WEB)

The public is invited

Aug
13
Wed
Defense-Abu Saleh Imtiaz @ Sorenson Molecular Biotechnology Building (SMBB) room 2660
Aug 13 @ 2:15 pm – 3:30 pm

Title: Piezoelectric micro-resonators on Si for inductor free embedded (on-chip) power converters in PV powered autonomous micro-systems


Abstract:
Microelectromechanical systems (MEMS) resonators on Si have the potential to replace the discrete passive components in a power converter. The main intention of this dissertation is to present a ring-shaped aluminum nitride (AlN) piezoelectric micro-resonator that can be used as an energy-transferring device to replace inductors/capacitors in low power resonant converters for biomedical applications in Autonomous Microsystems. The zero voltage switching (ZVS) condition for a series resonant converter incorporating the proposed MEMS resonator has been presented analytically and verified through experiment. This ZVS condition can be found in terms of the equivalent circuit parameters of the resonator. To the best of my knowledge, a ZVS model for thin film devices has not yet been reported in the literature. A CMOS-compatible fabrication process has been proposed and implemented. In addition, the fabricated devices have been characterized and experimental results are included. The first contour mode AlN MEMS resonator with moderately low resonant frequency and motional resistance is reported in this dissertation with measured resonant frequency and motional resistance of 87.28 MHz and 36.728 Ω respectively.
First part of this dissertation discusses the feasibility of PV powered autonomous micro-system. The reliability, efficiency and controllability of PV power systems can be increased by embedding the components of a typical power converter on the same Si substrate of a PV cell. In order to achieve more insight of the macro or surface electronics, a novel fabrication process along with experimental results have been presented in this dissertation demonstrating the integration of PV cells and major components needed to build a power converter on the same substrate/wafer. Because of the cell level power conversion, PV panels constructed from these cells are likely to be immune to partial shading and hot-spot effects. The effect of light exposure on converter switches has been analyzed to understand the converter behavior at various illumination levels. Simulation and experimental results have been provided to support this analysis. In addition to the process-related challenges and issues, this work explains the justification of this integration by achieving higher reliability, portability and complete modular construction for PV-based energy harvesting units for autonomous micro-systems.

Aug
25
Mon
Graduate Seminar – “Welcome and Introduction” @ Warnock (WEB 1250)
Aug 25 @ 3:00 pm – 4:00 pm
Graduate Seminar - "Welcome and Introduction" @ Warnock (WEB 1250)

Dr. Gianluca Lazzi

University of Utah Electrical & Computer Engineering Department

When: Monday, August 25, 2014 at 3:05 p.m.
Where: Warnock 1250

During this first Graduate Seminar of Fall 2014, Dr. Lazzi will welcome students to the 2014-2015 academic year and go over the format for Graduate Seminar for the remainder of the semester.

Aug
27
Wed
Mohamed Othman Defense @ Chemical Engineering Conference Room MEB 3291
Aug 27 @ 9:00 am – 11:00 am

UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT

DISSERTATION DEFENSE FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

by

Mohamed Abou Bakr Othman
Advisor: Behrouz Farhang

Detection of Nondeterministic Linear Chirps in non-Gaussian Noise Background


Chirp signals arise in many applications of digital signal processing. In this dissertation, we address the problem of detection of chirp signals that are encountered in a bistatic radar which we are developing for remote sensing of cosmic ray induced air showers. The received echoes from the air showers are characterized by their large Doppler shift (several tens of MHz), and very short sweep period (~10s). This makes our astrophysical problem a challenging one, since a very short sweep period is equivalent to a very low energy chirp signal. Furthermore, the related parameters of the received echoes are nondeterministic since they are tied to the physical parameters of the air showers that are stochastic in nature. In addition, our problem is characterized by the rarity of the expected chirp-echoes to be received, few events per week, and thus, background noise reception is the case most of the time. The primary focus of this research is to address these challenges and find an optimized detection approach under the existing receiver environment which contains non-Gaussian noise and characterized by low signal-to-noise ratio (SNR).

Matched filters are commonly used in radar systems when the chirp signal is known. In our first method, we revisit this context and use a “matched-filter” as a basis of building a rake-like receiver which consists of a set of filters matched to quantized chirp rates, logarithmically distributed within the chirp-rate interval of interest. We examine the detection capability of the proposed structure through extensive theoretical and numerical analysis. Theoretical analysis and simulation results prove that the proposed detector has high detection capability for a range of chirp slopes in a low SNR environment.

A major source of false-alarms found to be due to sudden noise spikes that cover wide frequency bands. These transient signals have high amplitudes and occur at random time instants. This leads to erroneous detection decision. We study the influence of amplitude limiting the noisy signal on reducing the received false alarms and enhancing the detection performance of the proposed rake-like receiver.

In our second method, we use Hough transform (HT), which is widely used in the area of image processing for the purpose of finding parameterized patterns, as a basis of building a robust detection technique. We examine the detection capability of the proposed structure through theoretical and numerical analysis. Our results prove that the proposed detector has high detection capability for a range of chirp slopes in a low SNR environment.

The introduced detection algorithms are implemented over a Virtex-5 FPGA. National Instruments modules are used as a high-performance custom hardware. Due to rarity of received echoes, we emulate the expected radar echoes to evaluate the system performance. The detection performance of the emulated echoes is examined using the implemented receiver at the field. Also, we compare the performance of both detectors.

 

Wednesday, August 27, 2014
9:00 a.m.
Chemical Engineering Conference Room
Merrill Engineering Building (MEB) Room 3291

The public is invited