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Full-Text Articles in Engineering

Sparse And Low Rank Signal Recovery With Partial Knowledge, Jinchun Zhan Jan 2015

Sparse And Low Rank Signal Recovery With Partial Knowledge, Jinchun Zhan

Graduate Theses and Dissertations

In the first part of this work, we study sparse recovery problem in the presence of bounded noise. We obtain performance guarantees for modified-CS and for its improved version, modified-CS-Add-LS-Del, for recursive reconstruction of a time sequence of sparse signals from a reduced set of noisy measurements available at each time. Under mild assumptions, we show that the support recovery error and reconstruction error of both algorithms are bounded by a time-invariant and small value at all times.

In the second part of this work, we study batch sparse recovery problem in the presence of large and low rank noise ...


Device Physics Of Organic And Perovskite Solar Cells, Mehran Samiee Esfahani Jan 2015

Device Physics Of Organic And Perovskite Solar Cells, Mehran Samiee Esfahani

Graduate Theses and Dissertations

We report on fundamental electronic properties of the PTB7:PCBM70 bulk heterojunction solar cells: Sub-gap quantum efficiency measurements determine the Urbach energy of tail states (33 meV) and D/A interfacial bandgap (1.34 eV). Density of deep defects is determined by capacitance spectroscopy, and is ~1016 cm-3.eV-1. By photo-current spectroscopy, we assess surface recombination velocity at D/A interface, which translates to a capture cross-section of ~10-16 cm2 for deep defects. These properties are then used in our analytical modeling. Using a multiple-level trap model, we compute recombination rates in the cells. The model can predict dark saturation ...


Multilevel Sequence Detection For Dynamic Mode Atomic Force Microscopy, Yan Ren Jan 2015

Multilevel Sequence Detection For Dynamic Mode Atomic Force Microscopy, Yan Ren

Graduate Theses and Dissertations

The atomic force microscope is an instrument that is widely used in fields such as biology, chemistry and medicine for imaging at the atomic level. In this work, we consider a specific mode of AFM usage, known as the dynamic mode where the AFM cantilever probe is forced sinusoidally. In the absence of interaction with the sample being imaged, the cantilever follows a predictable sinusoidal trajectory. The deflection of the cantilever probe changes when it interacts with the sample being imaged and imaging is performed by interpreting these changes.

In this work, we present a sequence detection based algorithm that ...


Mems-Compatible Processes For Fabricating Nanostructures And Their Applications, Yuan He Jan 2015

Mems-Compatible Processes For Fabricating Nanostructures And Their Applications, Yuan He

Graduate Theses and Dissertations

During the past decades, many different nanostructures have been successfully synthesized and developed. Due to their nanoscale dimensions, the nanostructures (i.e., nanostructured film, nanotubes, quantum dots) usually exhibit unique optical, electronic, or mechanical properties, which differ from those of the same bulk material. This dissertation focuses on the development and applications of two types of nanostructures: high aspect ratio (HAR) silicon nanostructures and anodic aluminum oxide (AAO) nanopores.

(i) High aspect ratio (HAR) silicon nanostructures, including nanopillars, nanoforest and nanotubes, have attracted enormous attention in the fields of energy harvesting and storage, biomedical sensing, drug delivery, and template-based nanofabrication ...


Switched-Compensation Technique In Switched-Capacitor Circuits For Achieving Fast Settling Performance, Jiaming Liu Jan 2015

Switched-Compensation Technique In Switched-Capacitor Circuits For Achieving Fast Settling Performance, Jiaming Liu

Graduate Theses and Dissertations

Resolving stability issue is one of the major challenges in designing a perfect op-amp, the most widely used analog circuit block. Many compensation techniques have been proposed to improve the stability performance of op amps, but virtually all these techniques were developed for continuous-time applications and subsequently applied to discrete-time applications (e.g., switched-capacitor circuits). Since the early 1980s, an increasing number of op-amps have been used in switched-capacitor circuits with no special compensation method applied. Consequently, there remains a need to explore the possibility of designing a unique compensation method specifically for switched-capacitor use.

A new switched-compensation technique (SCT ...


New Developments In Magneto-Optic Interferometric Switching, John William Pritchard Jan 2015

New Developments In Magneto-Optic Interferometric Switching, John William Pritchard

Graduate Theses and Dissertations

In the next few decades, it is likely that high bandwidth wireless and optical technologies will be placed in the spotlight as the dominant avenues for communication all over the world. It is arguable that this is currently the case, and that the expectation for higher data transfer speeds, more secure and reliable transmission, and longer communication range is on an exponential rise. Thus, much effort and emphasis is being put on these technologies to advance as quickly as possible.

For optical systems, the majority of research has been focused on the realization of all-optical transmission, that is, transmission such ...


Assessment Of Vlsi Resources Requirement For A Sliced Trusted Platform Module, Hala Mohammad Hamadeh Jan 2015

Assessment Of Vlsi Resources Requirement For A Sliced Trusted Platform Module, Hala Mohammad Hamadeh

Graduate Theses and Dissertations

Recent increases in cybercrime suggest questions such as: How can one trust a secure system? How can one protect private information from being stolen and maintain security? Trust in any system requires a foundation or root of trust. A root of trust is necessary to establish confidence that a machine is clean and that a software execution environment is secure. A root of trust can be implemented using the Trusted Platform Module (TPM), which is promising for enhancing security of general-purpose computing systems.

In cloud computing, one of the proposed approaches is to use homomorphic encryption to create k program ...


Hardware Trojan Vulnerability, Xing Cao Jan 2015

Hardware Trojan Vulnerability, Xing Cao

Graduate Theses and Dissertations

Many basic analog blocks and structures, which contain positive feedback loops, are vulnerable to the presence of one or more undesired stable equilibrium points. The phenomena of multiple equilibrium points is investigated with emphasis on using a temperature-domain representation to identify equilibrium points in some circuits that have a single positive feedback loop. By example, it is shown that the presence of multiple equilibrium points can often be observed as hysteresis in a plot of an output circuit electrical variable versus temperature obtained from a bidirectional temperature sweep over a temperature interval [T_1,T_2] of interest. The hysteresis can be ...


Detection Of Sub-Surface Stresses In Ferromagnetic Materials Using A New Barkhausen Noise Method, Orfeas Kypris Jan 2015

Detection Of Sub-Surface Stresses In Ferromagnetic Materials Using A New Barkhausen Noise Method, Orfeas Kypris

Graduate Theses and Dissertations

In this work, a new, non-destructive method for obtaining stress-depth gradients in ferromagnetic structures was developed, using the information contained within magnetic Barkhausen emissions. A depth- and stress-dependent model for the frequency spectrum of Barkhausen emissions was derived and fitted to measured data obtained from steel samples with controlled stress-depth gradients. To achieve this, a library of signal processing and optimization algorithms was developed, which allowed the analysis of large datasets. To validate experimental procedures, a number of solid mechanics finite element simulations were carried out. Proof of concept is demonstrated by assuming linear stress-depth gradients and successfully calculating the ...


Defect Characterization Of 4h-Sic By Deep Level Transient Spectroscopy (Dlts) And Influence Of Defects On Device Performance, Mohammad Abdul Mannan Jan 2015

Defect Characterization Of 4h-Sic By Deep Level Transient Spectroscopy (Dlts) And Influence Of Defects On Device Performance, Mohammad Abdul Mannan

Theses and Dissertations

Silicon carbide (SiC) is one of the key materials for high power opto-electronic devices due to its superior material properties over conventional semiconductors (e.g., Si, Ge, GaAs, etc). SiC is also very stable and a highly suitable material for radiation detection at room temperature and above. The availability of detector grade single crystalline bulk SiC is limited by the existing crystal growth techniques which introduce extended and microscopic crystallographic defects during the growth process. Recently, SiC based high-resolution semiconductor detectors for ionizing radiation have attracted world-wide attention due to the availability of high resistive, highly crystalline epitaxial layers with ...


Comparison Between Single Band And Concurrent Multi-Band Linear Power Amplifiers, Zhen Zhang Jan 2015

Comparison Between Single Band And Concurrent Multi-Band Linear Power Amplifiers, Zhen Zhang

Graduate Theses and Dissertations

Currently the multiple wireless data transmission technologies have been commercially implemented, such as long-term evolution (LTE), Wi-Fi, and Bluetooth. There is a keen requirement to combine the power amplifiers for those technologies into a single one which can amplifies concurrent multi-band signals. On the physically layer, there are two popular architectures, namely parallel single-band power amplifiers and concurrent multi-band power amplifiers.

In this thesis, quantitative comparison between parallel single-band power amplifiers and concurrent multi-band power amplifiers has been presented theoretically in the aspects of area, drain efficiency and linearity. Methods of calculating drain efficiency is derived for concurrent multi-band PAs ...


Dual-Frequency Single-Inductor Multiple-Output (Df-Simo) Power Converter Topology For Soc Applications, Chih-Wei Chen Jan 2015

Dual-Frequency Single-Inductor Multiple-Output (Df-Simo) Power Converter Topology For Soc Applications, Chih-Wei Chen

Graduate Theses and Dissertations

Modern mixed-signal SoCs integrate a large number of sub-systems in a single nanometer CMOS chip. Each sub-system typically requires its own independent and well-isolated power supply. However, to build these power supplies requires many large off-chip passive components, and thus the bill of material, the package pin count, and the printed circuit board area and complexity increase dramatically, leading to higher overall cost. Conventional (single-frequency) Single-Inductor Multiple-Output (SIMO) power converter topology can be employed to reduce the burden of off-chip inductors while producing a large number of outputs. However, this strategy requires even larger off-chip output capacitors than single-output converters ...


New Ancillary Service Market Design To Improve Mw-Frequency Performance: Reserve Adequacy And Resource Flexibility, Guangyuan Zhang Jan 2015

New Ancillary Service Market Design To Improve Mw-Frequency Performance: Reserve Adequacy And Resource Flexibility, Guangyuan Zhang

Graduate Theses and Dissertations

With the high penetration of renewable energy resources such as wind and solar, the power system is facing the degradation of frequency response. The major reasons for the degradation of frequency performance can be summarized as following reasons: first, the cheap and clean renewable energy is displacing the conventional thermal generator. While the wind turbine is connecting with the bulk power grid with AC-DC-AC converter and the solar panel is connected to the grid via the DC-AC inverter. The power electronic device isolates the wind or solar unit from the synchronous bulk power grid, therefore, the wind and solar is ...


A Graphical Method For Determining The Uniqueness Of Operating Points In Self-Biasing Circuits, Shiya Liu Jan 2015

A Graphical Method For Determining The Uniqueness Of Operating Points In Self-Biasing Circuits, Shiya Liu

Graduate Theses and Dissertations

In self-biasing circuits, designers often use feedbacks to reduce the power-supply sensitivity and minimize the effects of process and temperature variations. Many self-stabilized circuits are used in SOC circuits even when the SOC has a small amount of AMS content. It is well-known that these self-stabilized circuits are vulnerable to not "starting-up" correctly so start-up circuits are often included to prevent the circuit from getting stuck in an undesired stable operating point. Determining the uniqueness of an operating point in a circuit is challenging since circuit simulators only give a single operating point rather than all operating points. Moreover, this ...


Droplet Actuator System For Molecular Diagnostic Applications, Riley Brien Jan 2015

Droplet Actuator System For Molecular Diagnostic Applications, Riley Brien

Graduate Theses and Dissertations

In biological research, routine liquid handling operations require considerable human effort and manual labor. For this reason, experiments in clinical laboratories are time-consuming and thus expensive. Recently, advances in point-of-care “lab-on-a-chip” systems have allowed more efficient ways of sample handling and analysis. Such systems often operate by automated manipulation of discrete liquid droplets, and are increasing sought to improve experimental throughput. Various techniques have been developed to manipulate discrete droplets, such as digital microfluidics, surface acoustic waves, and texture ratchets. In this thesis, a novel droplet actuation system is presented that can be applied for molecular diagnostic tests. The system ...