Digital Commons Network^™

Locating Current Paths Via Time Synchronized Measurements In A Multiphase Dcdc Buck Converter And A High Frequency Analytical Model For The Common-Mode Impedance Of A Ferrite Choke, Peng Shao

Masters Theses

"In the first section, it introduces a novel method to localize current from multiple sources. The identification of return current paths is often a key element in understanding the root cause of a product's radiated emissions. In a complex system, multiple sources can contribute to the current at the same location and frequency. The source of the current can be identified by correlating the current to different sources. However, the multiphase buck converter phases do not switch at the same time. Thus, synchronizing to a specific phase makes it possible to determine how the current from a specific phase spreads …

Unified Knowledge Model For Stability Analysis In Cyber Physical Systems, Tamal Paul

Masters Theses

"The amalgamation and coordination between computational processes and physical components represent the very basis of cyber-physical systems. A diverse range of CPS challenges had been addressed through numerous workshops and conferences over the past decade. Finding a common semantic among these diverse components which promotes system synthesis, verification and monitoring is a significant challenge in the cyber-physical research domain. Computational correctness, network timing and frequency response are system aspects that conspire to impede design, verification and monitoring. The objective of cyber-physical research is to unify these diverse aspects by developing common semantics that span each aspect of a CPS. The …

3d Spatio-Temporal Analysis For Compressive Sensing In Magnetic Resonance Imaging Of The Murine Cardiac Cycle, Brice Aaron Hirst

Masters Theses

"This thesis consists of two major contributions, each of which has been prepared in a conference paper. These papers will be submitted for publication in the SPIE 2013 Medical Imaging Conference and the ASEE 2013 Annual Conference.

The first paper explores a three-dimensional compressive sensing (CS) technique for reducing measurement time in MR imaging of the murine (mouse) cardiac cycle. By randomly undersampling a single 2D slice of a mouse heart at regular time intervals as it expands and contracts through the stages of a heartbeat, a CS reconstruction algorithm can be made to exploit transform sparsity in time as …

Implementation And Evaluation Of Spatial Audio Recording And Rendering Techniques, Jayasecha Raghavendra Nimmala

Masters Theses

"The thesis is divided into two main sections. First half describes the implementation of different adaptive beamforming techniques. Adaptive beamforming techniques are widely used in many real world applications like teleconferencing, speech recognition, devices for the hearing impaired, radar, sonar, etc. The beamformer is an array of sensors which can be electronically steered to any particular direction to enhance the signal in the direction of interest while at the same time suppressing interference or jammers coming from other directions.

In our experiment, we implement both the regularized minimum variance distortionless receiver (MVDR) and the generalized sidelobe canceller (GSC). The beamforming …

Optical Coherence Tomography For Biomedical Imaging, Edward Henry Pienkowski

Masters Theses

"Two projects are presented in this thesis; 1) a hollow core, concentrically symmetric beam splitting Michelson interferometric probe for optical coherence tomography and 2) the imaging of bioactive ceramic scaffolds using swept source optical coherence tomography. The key component of the interferometer is a compact, small diameter probe composed of a collimating lens, hollow core beam splitting tube, and a focusing lens intended to be used for endoscopic imaging. The beam splitting tube was created by sputter coating the distal endface of a finely polished thick wall capillary tube with a highly reflective gold layer. Part of the light travels …

Field Coupled Electrostatic Discharge Sensitivity Database, Zhen Li

Masters Theses

"Electrostatic Discharge (ESD) can disrupt the performance of an electronic system, like an MP3 player either by injected currents or by transient fields. It is possible to predict at least the approximate transient field levels inside a system, but it is difficult to determine the response of ICs subjected to these fields, as no IC specific data is available, and as it is often too involved to measure the sensitivity of every IC possibly used in a product. As deterministic solutions are difficult to achieve, a statistical approach has been selected in this research. The goal of this database for …

Laboratory Implementations Of Pmsm Drive In Hybrid Electric Vehicles Applications, Amir E. Saad

Masters Theses

"Field Programmable Gate Arrays (FPGAs) are one of the today's most successful technologies for developing systems that require real time operation and providing additional flexibility to the designer. This research is focused on developing a control board for a permanent magnet synchronous machine (PMSM) using an FPGA module. The board is configured for individual use of an FPGA, digital signal processor (DSP) or in combination to control the PMSM by generating the required Pulse Width Modulator (PWM) to the inverter in order to drive and control the speed of the PMSM. Since, the exact rotor position and speed are required …

Sapphire Fiber Numerical Aperture Measurement And Sensor Fabrication, Xia Fang

Masters Theses

"A sapphire fiber is made of single crystal aluminum oxide with hexagonal crystal structure. It is attractive for high temperature application for its chemical resistance and high melting point of 2053⁰C. It is good for infrared transmission with a small attenuation of 0.13dB per meter at the wavelength of 2.94µm, and it can also deliver very high optical energy. However, a typical sapphire fiber has a rough surface and a nonperfect crystalline structure. Also, a sapphire fiber cannot be grown in a core-clad structure. The un-cladded waveguide imposes a number of undesirable characteristics on sensing applications, e.g., unpredictable light loss …

Electromagnetic Compatibility Of Integrated Circuit Clock Design, Vijay Kanagachalam

Masters Theses

"With advancements in technology, transistor sizes are shrinking resulting in reduced power supply voltage and thereby reduced noise margin which makes the devices susceptible to electromagnetic noises. The trend of integrating more circuits on a single die at ever growing operating frequency increases interference among circuits and with the outside world. In order to make circuits electromagnetically compatible, it is essential to reduce emissions from the circuit and understand the causes of failure due to interference of noise from other sources coupling into the circuit so that a robust design can be created.

Two topics are explored in this thesis. …

Spiking Neural Networks Encoding And Decoding Algorithms For Time Series Estimation And System Identification, Sinchan Roychowdhury

Masters Theses

"Artificial Neural networks (ANNs) have increasingly been applied to different system identification, pattern recognition and function approximation problems. The predominantly used neural network architectures are the feedforward and feedback networks. Multilayer perceptrons and radial basis function networks are among the most commonly used feed-forward architecture neural networks and the Elman and Jordan networks are the most widely used recurrent neural networks. These networks are also called as second generation ANNs.

This thesis focuses on the third generation ANNs which are biologically inspired and operate on the same principles as the living neurons. These are also known as biologically inspired artificial …

Automatic Detection Of Annular-Granular Patterns In Melanoma In Situ Dermoscopy Images, Parivash Hajiyani

Masters Theses

"Early detection of malignant melanoma greatly benefits patients, as the overall success is dependent on finding these melanomas before they reach the invasive stage. Dermoscopy is a non-invasive skin imaging technique that studies have shown can improve the diagnostic accuracy of dermatologists by as much as 30% over clinical examination. In this project machine vision and image analysis techniques are used to detect annular granular areas in dermoscopy images automatically. The proposed algorithm utilizes the luminance ratio between annular and granular areas within the darkest 30% of the lesion. All points whose luminance value are less than 30% of the …

Coaxial Cable Bragg Grating, Jie Huang

Masters Theses

"In order to ensure the continued safe and reliable operation of various civil structures, such as dams, bridges, and buildings, in situ strain monitoring is of great importance, especially for structures that may experience large strains. A new coaxial cable Bragg grating (CCBG) is developed as a strain sensor and the sensor's capacity for large range strain measurement is demonstrated for the first time. The sensor device is comprised of regularly spaced periodic discontinuities along a coaxial cable. The discontinuities are fabricated using a computer numerical controlled (CNC) machine to drill holes in the cable. Each discontinuity generates a weak …

Experimental Feasibility Study Of A Passive Radio Frequency Identification-Based Distributed Beamforming Framework And Radio Frequency Tag Design For Achieving Dynamic Beamforming, Pratim Shah

Masters Theses

"Passive UHF RFID tags works on the principle of backscattering mechanism. In realistic environment, there are multiple objects and tags that create complex, multipath propagation scenarios with numerous null-points, reduced read range and read rate.

In general, the RF frontend of tags could be controlled such that the negative effects of multipath propagation are reduced or even inverted thus implementing a virtual beamforming. The theoretical framework of beamforming in RFID system, using additional tags as virtual antenna arrays, has been discussed before. The presented study evaluates the feasibility of such beamforming in passive RFID systems. Moreover, it synthesizes an appropriate …

A Decentralized Fault Diagnosis And Prognosis Scheme For Nonlinear Interconnected Systems, Deepthi Shreeya Lathamaheswari Raja

Masters Theses

"Today's systems are getting more complex with a significant number of variables to be monitored for information processing to aid in fault diagnosis and prognosis. Centralized diagnosis and prognosis schemes are not preferred for such complex systems as they lead to delayed or missed alarms and possibly catastropic [sic] failures. Instead, this thesis addresses a decentralized fault diagnosis and prognosis scheme both in continuous and discrete-time for nonlinear complex systems which can be divided into smaller subsystems. Such complex systems are referred to as a large-scale interconnected nonlinear system. This thesis is presented in the form of two papers first …

Experimental Investigation Of Rf Fading Channels And Receiver Detection, Saurav Kumar Subedi

Masters Theses

"This thesis includes experimental investigation of Multiple Input Multiple Output (MIMO) Radio Frequency (RF) fading channels and detection of superregenerative receivers. Details of experiment design and hardware implementation, data acquisition and analysis, and results for both studies are chronicled into two papers. The first paper investigates the validity of the discrete time triply selective fading channel model for fixed mobile-to-mobile MIMO channels. A 2x2 MIMO-OFDM testbed using the Altera Stratix III EP3SL150F field programmable gate array (FPGA) DSP development kit is used for acquiring experimental data. Subsequent offline signal processing and analysis are done in MATLAB. The Channel Impulse Response …

A Digitally Implemented Practical Photovoltaic Simulator With A Double Current Mode Controller, Jie Ang Zhao

Masters Theses

"This thesis presents a microcontroller- and DC-DC converter-based photovoltaic (PV) simulator which emulates the output characteristic of a PV module. The current-voltage (IV) characteristic of a PV module is implemented as a look-up-table that generates an output reference current based on a measured output voltage. The control mechanism is based on a double current mode controller that consists of a predictive current mode controller and a proportional-integral (PI) controller arranged in an inner loop and outer loop configuration. The PI controller is designed based on classical phase margin and gain margin criteria to ensure system stability. The performance of the …

Statistical And Predictive Modeling Of Automated Meter Reading System Outages, Prasad Prabhakar Shinde

Masters Theses

"An Automated Meter Reading (AMR) system is a metering technology that enables power utility companies to receive customers' energy usage data centrally over a communication network. The installed automated meters also provide a daily log of outage events for each customer. A utility company can greatly benefit by using this information for outage management and to improve reliability. However, outage data is frequently corrupted and the outage flags registered by the customers' meters do not necessarily reflect true outages. This thesis focuses on developing methods to analyze outage data and building a model to identify good data versus spurious indications. …

Path Planning For General Mazes, Grant Gilbert Arthur Rivera

Masters Theses

Path planning is used in, but not limited to robotics, telemetry, aerospace, and medical applications. The goal of the path planning is to identify a route from an origination point to a destination point while avoiding obstacles. This path might not always be the shortest in distance as time, terrain, speed limits, and many other factors can affect the optimality of the path. However, in this thesis, the length, computational time, and the smoothness of the path are the only constraints that will be considered with the length of the path being the most important. There are a variety of …

Reliability Evaluation Of Distribution Systems Containing Renewable Distributed Generations, Abdulaziz Abddullah Alkuhayli

Masters Theses

Reliability evaluation of distribution networks, including islanded microgrid cases, is presented. The Monte Carlo simulation algorithm is applied to a test network. The network includes three types of distributed energy resources solar photovoltaic (PV), wind turbine (WT) and gas turbine (GT). These distributed generators contribute to supply part of the load during grid-connected mode, but supply the entire load during islanded microgrid operation. PV and WT stochastic models have been used to simulate the randomness of these resources. This study shows that the implementation of distributed generations can improve the reliability of the distribution networks.

Stochastic Model For Solar Sensor Array Data, Faris Alfaris

Masters Theses

Statistical approaches are often used in time series analysis, for example, to predict the future trend of a time series. Trend forecasting can be applied in many time related parameters such as: solar radiation, generation of electricity and other variables related to time series to improve the efficiency and to set the design requirements. Since the design of any solar energy system requires knowledge of the availability of solar radiation data at the location of interest. Therefore, this research seeks the application of a statistical model to fit the solar radiation time series and predict the future values. There are …

Maximum Power Point Tracking Control Of Hydrokinetic Turbine And Low-Speed High-Thrust Permanent Magnet Generator Design, Hailong Zhou

Masters Theses

"River-based hydrokinetic turbine power generation systems have been studied to introduce an effective energy flow control method. Hydrokinetic turbine systems share a lot of similarities with wind turbine systems in terms of physical principles of operation, electrical hardware, and variable speed capability for optimal energy extraction. A multipole permanent magnet synchronous generator is used to generate electric power because of its ability to reach high power density and high thrust at low speed. A 3-phase diode rectifier is used to convert AC power from the generator into DC power and a boost converter is used to implement energy flow control. …

Multiple-Input Multiple-Output System On A Spinning Vehicle With Unknown Channel State Information, Aditya Muralidhar

Masters Theses

"This thesis work presents the investigations into the performance of a multiple-input multiple-output (MIMO) system with its transmitters on a spinning vehicle and no available channel state information (CSI) at the transmitter or the receiver. The linear least squares approach is used to estimate the channel and the estimation error is measured. The spinning is simulated based on a sample radiation pattern of a patch antenna. The antenna gains at different angles are obtained from this pattern and are used to model spinning. Spinning gives rise to a periodic component in the channel which can be estimated based on the …

Control And Operation Of Multiple Distributed Generators In A Microgrid, Shyam Naren Bhaskara

Masters Theses

"Small sized synchronous generator based distributed generators (DG) often have low start-up times, and can serve as dispatchable generators in a microgrid environment. The advantage is that it allows the power network to operate in a true smart grid environment. The disadvantage is that such DGs typically tend to have low inertia and the prime movers driving these resources need to be controlled in real time for them to operate effectively in islanded, grid-connected modes and during transition from grid-connected mode to islanded mode and vice versa. When multiple DGs are present in the microgrid, the overall control can become …

A Study Of Wavelet-Based Noise Reduction Techniques In Mammograms, Varun Shah

Masters Theses

"Breast cancer is one of the most common cancers and claims over one thousand lives every day. Breast cancer turns fatal only when diagnosed in late stages, but can be cured when diagnosed in its early stages. Over the last two decades, Digital Mammography has served the diagnosis of breast cancer. It is a very powerful aid for early detection of breast cancer. However, the images produced by mammography typically contain a great amount noise from the inherent characteristics of the imaging system and the radiation involved. Shot noise or quantum noise is the most significant noise which emerges as …

Laminate Dielectric And Foil Characterization For Signal Integrity On Printed Circuit Board, Aleksandr Yakubovich Gafarov

Masters Theses

"Accurate characterization of laminate dielectrics as substrates of printed circuit boards (PCB) over a wide frequency range (from tens megahertz to tens gigahertz) is important from a signal integrity (SI) point of view. Accurate knowledge of dielectric constants (DK) and dissipation factors (DF), or loss tangents, of laminate dielectrics, as well as loss in conductors, as functions of frequency over a wide frequency range, are needed to the designers of high-speed digital electronics.

An "in situ" wideband traveling-wave technique based on measuring S-parameters of the PCB test vehicles with auxiliary "through-reflect-line" (TRL) calibration patterns has been developed. This technique has …

Cooperative Power Control Approaches Towards Fair Radio Resource Allocation For Wireless Network, Liuju Wu

Masters Theses

"Performance optimization in wireless networks is a complex problem due to variability and dynamics in network topology and density, traffic patterns, mutual interference, channel uncertainties, etc. Opportunistic or selfish approaches may result in unbalanced allocation of channel capacity where particular links are overshadowed. This degrades overall network fairness and hinders a multi-hop communication by creating bottlenecks. A desired approach should allocate channel capacity proportionally to traffic priority in a cooperative manner. This work consists of two chapters that address the fairness share problem in wireless ad hoc, peer-to-peer networks and resource allocation within Cognitive Radio network. In the first paper, …

Computation Of Power Plane Pair Inductance, Measurement Of Multiple Switching Current Components And Switching Current Measurement For Multiple Ics With An Island Structure, Liang Li

Masters Theses

"The first part of the thesis presents the computation of power / ground plane pair inductance based on Partial Element Equivalent Circuit (PEEC) method in power distribution network (PDN) design. An efficient approach for the inductance computation is investigated. Speed-up techniques are employed include using the faster decay of mutual coupling due to the "differential" currents (same magnitude but opposite directions) in the two planes. Also, an approximate rectangular mesh reduction method is introduced which allows a local increase in mesh density.

The second part presents a measurement-based data-processing approach to obtain parameters of multiple current components through a bulk …

Identification Of Starry Milia-Like Cysts In Seborrheic Keratoses And Malignant Melanomas Using Image Processing Techniques, Viswanaath Subramanian

Masters Theses

"Seborrheic keratoses are the most common benign tumors found in older individuals. Seborrheic keratoses are normally benign in nature, but sometimes in a large lesion area of seborrheic keratoses, secondary tumors, or squamous cell carcinoma in situ or malignant melanoma may occur. It has been found that seborrheic keratoses have a few features that distinguish them from melanomas. Milia-like cysts, comedo-like openings and network-like structures are the most prominent features found in seborrheic keratoses. Comedo-like openings are pigmented structures and are mostly oval yellowish, brown or black in appearance. They can also be observed in melanocytic lesions and melanomas. Milia-like …

Intelligent Energy Management And Demand-Response Control For A Photovoltaic-Battery System, Yang Liu

Masters Theses

"The work shown in this thesis is to develop an intelligent energy management and demand-response controller (IEMDC) for a photovoltaic-battery (PVB) system with a programmable load. Specifically, the research work related to this issue focuses on the modeling and real-time simulation of a microgrid with an emphasis on photovoltaic, battery and programmable load and the development of an energy management controller for optimally dispatching the power from the PVB system to the loads. The IEMDC is used for daytime grid-independent operation. The energy management controller is based on fuzzy logic controller (FLC) whose membership functions are optimized using mean-variance optimization …

Information Theoretic Analysis And Design Of Passive Wireless Backscatter Sensor Networks, Aditya V. Padaki

Masters Theses

"Passive, backscatter-based communication technology is increasingly employed in wireless sensing applications. It offers several advantages including small form factor, battery-less operation, increased system lifetime, small configurations, etc. The main focus of this work is to study the theoretical limits of the network performance in such passive sensor networks. In addition to the traditional direct communication between an active and several passive devices (like RFID), the information theoretic analysis considers two new communication frameworks: multi-hop and multipath passive networks. These new frameworks are demonstrated through theoretical and simulation results to improve the network performance and fairness over the traditional direct communication. …