Engineering Commons^™

Stability And Static Noise Margin Analysis Of Static Random Access Memory, Rajasekhar Keerthi

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The transistor mismatch can be described as two closely placed identical transistors have important differences in their electrical parameters as threshold voltage, body factor and current factor and make integrated circuit design and fabrication less predictable and controllable. Stability of a static random access memory (SRAM) is defined through its ability to retain the data at low-VDD. It is seriously affected by increased variability of transistor mismatch and decreased supply voltage and therefore becomes a major limitation of overall performance of low-voltage SRAM in nanometer CMOS process. The stability limitation is addressed through the design of a seven-transistor (7T) SRAM …

An Analog Evolvable Hardware Device For Active Control, Saranyan A. Vigraham

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The field of Evolvable Hardware (EH) has recently gained a lot of interest due to the novel methodology it offers for designing electrical circuits and machines. EH techniques involve configuring a reconfigurable hardware platform with the aid of learning engines such as evolutionary algorithms. The EH devices normally act as closed loop controllers with the capability of learning necessary control laws adaptively. Current EH practices have several shortcomings, which have restricted their use as reliable controllers. This dissertation will present an improved EH device based on behavioral reconfigurability that addresses the current open challenges in the field of analog Evolvable …

Design Of A Controller To Control Light Level In A Commercial Office, Saeid Javidbakht

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Proper amount of light in a business office is important for health and productivity of the employees. On a sunny day, there may be more than enough light entering the office from outside to carry out the necessary tasks. Presently, the main source of light in most offices is the fluorescent lamp. Thus, It is possible to save energy by dimming the fluorescent lamp. Dimming of the fluorescent lamp is possible by changing the frequency of the sinusoidal voltage or current. Hence, there is a need of a control system to adjust the light from the fixtures based on the …

Functional Interplay Between Subthreshold Ion Channels In Preautonomic Neurons Of The Hypothalamic Paraventricular Nucleus In Health And Disease Conditions, Patrick M. Sonner

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Under normal conditions, blood pressure is tightly regulated through autonomic tonic and reflex mechanisms. However, when the set-point for blood pressure is chronically elevated, hypertension occurs. Hypertension if untreated can lead to further complications including heart failure, stroke and kidney failure. Elevated sympathetic outflow is known to contribute to the development and/or maintenance of hypertension, and while the hypothalamic paraventricular nucleus (PVN), a preautonomic center, has been implicated in the elevation of sympathetic activity during hypertension, the precise pathophysiological mechanisms underlying sympathoexcitation remain unclear. Subthreshold ion channels, including the A-type K ⁺(I _A) and the T-type Ca ^{2+ …}

Non-Cooperative Modulation Recognition Via Exploitation Of Cyclic Statistics, Eric C. Like

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This research proposes and evaluates a feature based modulation classification system designed to discriminate between AM, BFSK, OFDM, DS-CDMA, 4-ASK, 8-ASK, BPSK, QPSK, 8-PSK, 16- PSK, 16-QAM, and 64-QAM signals without a priori knowledge of critical signal parameters, including carrier frequency, symbol rate, or phase offset, among others. The classifier is based on the principles of cyclostationarity and leverages cyclic statistics to make its classification decision. The classification process is performed in a hierarchical process in order to exploit the lower variance of lower order cyclic statistics before making use of the higher order cyclic statistics. The initial classification is …

Fabrication And Testing Of Scaffolds For Cell Growth From Ionic Liquid Solubilized Fibroin, Maneesh Kumar Gupta

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The advent of tissue engineering has spurred research into developing materials to act as scaffolds for tissue growth. These scaffolds require materials capable of mimicking the in vivo conditions so that tissues can be grown effectively in vitro. Silk is an attractive biomaterial for use in tissue engineering applications because of its slow degradation, excellent mechanical properties, and biocompatibility. The major objective of the research in this thesis is to demonstrate a simple method to cast films directly from silk fibroin dissolved in an ionic liquid. The films cast from the silk ionic liquid solution were found to support normal …

Particle Based Plasma Simulation For An Ion Engine Discharge Chamber, Sudhakar Mahalingam

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Design of the next generation of ion engines can benefit from detailed computer simulations of the plasma in the discharge chamber. In this work a complete particle based approach has been taken to model the discharge chamber plasma.This is the first time that simplifying continuum assumptions on the particle motion have not been made in a discharge chamber model. Because of the long mean free paths of the particles in the discharge chamber continuum models are questionable. The PIC-MCC model developed in this work tracks following particles: neutrals, singly charged ions, doubly charged ions, secondary electrons, and primary electrons. The …

Comparative Microarray Data Mining, Shihong Mao

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As a revolutionary technology, microarrays have great potential to provide genome-wide patterns of gene expression, to make accurate medical diagnosis, and to explore genetic causes underlying diseases. It is commonly believed that suitable analysis of microarray datasets can lead to achieve the above goals. While much has been done in microarray data mining, few previous studies, if any, focused on multiple datasets at the comparative level. This dissertation aims to fill this gap by developing tools and methods for set-based comparative microarray data mining. Specifically, we mine highly differentiative gene groups (HDGGs) from given datasets/classes, evaluate the concordance of datasets …

A Hybrid Approach To Retrieving Web Documents And Semantic Web Data, Trivikram Immaneni

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The Semantic Web has been evolving into a property-linked web of RDF data, conceptually divorced from (but physically housed in) the World Wide Web of hyperlinked documents. Data Retrieval techniques are typically used to retrieve data from the Semantic Web while Information Retrieval techniques are used to retrieve documents from the Hypertext Web. Conceptually unifying the two webs enables the exploitation of their interconnections resulting in benefits to both data and document retrieval. Towards this end, we present the Unified Web model that integrates the two webs and formalizes the structure and the semantics of their interconnections. We present a …

Bibliography Tools In The Context Of Www And Latex, Munushree Thummala

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Preparation of academic papers involves not only the creative processes but also the more mechanical tasks such as adjusting the form and style to suit the demands of the publishing journal or conference. Among several packages that help in these rather tedious mechanical tasks, the TEX + LATEX + BibTEX combination is extremely popular. This thesis is about tools that help in the necessary task of citing related work accurately. It focuses on three aspects of this larger bibliography frame work: (i) a survey of existing bibliography formats and tools, (ii) a database view of BibTEX files and functionality that …

Manipulation Of Polystyrene Microparticles On A Microchannel Glass, Ravi Mamillapalli, Henry D. Young

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Bulk quantities of spherical microbeads have various applications in research and industrial fields. Simple techniques are required to be developed in order to manipulate and modify large numbers of these beads simultaneously. In our experiment, a microchannel glass-based microfluidic device is used to actuate large numbers of microbeads in parallel. The microchannel glass used in these experiments contains channels 4.1 μm in diameter. The microbeads are polystyrene beads which are superparamagnetic in nature and 5-6 μm in diameter. An aqueous suspension of microbeads is injected into a 2-chamber fluid cell that contains a separator, microchannel glass. The beads are reversibly …

Multi-Attribute Optimization Based On Conjoint Analysis, Hemanth K. Amarchinta

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Over the last thirty years, there were tremendous advances in multidisciplinary design optimization in reducing computational cost, developing algorithms for efficient sensitivity analysis in reaching an optimum. Most of these efforts assumed a single objective (attribute) function and a multitude of constraints. Very little work has been done in including the designer's preferences as part of the optimization scheme and in addressing the ability to handle multiple attributes simultaneously. This need to develop a systematic method for including designer's preferences is the main focus of this research work. The concept of modeling preferences among multi-attribute alternatives is prevalent in consumer …

Cognitively-Engineered Multisensor Data Fusion Systems For Military Applications, Amanda Christine Muller

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The fusion of imagery from multiple sensors is a field of research that has been gaining prominence in the scientific community in recent years. The technical aspects of combining multisensory information have been and are currently being studied extensively. However, the cognitive aspects of multisensor data fusion have not received so much attention. Prior research in the field of cognitive engineering has shown that the cognitive aspects of any human-machine system should be taken into consideration in order to achieve systems that are both safe and useful. The goal of this research was to model how humans interpret multisensory data, …

Simulation And Analysis Of Rfid Localization Algorithms, Zubin Shah

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Radio frequency identification (RFID) based localization systems provide a unique approach to localize mobile entities equipped with RFID readers or tagged with RFID tags. UHF RFID systems using passive tags are a good choice considering their cost, reading range, and reliability. With global acceptance and deployment of UHF RFID systems using passive tags for tracking and identification, virtually everything around us can be tagged with small and low-cost passive RFID tags. This thesis describes a Monte Carlo Localization based algorithm to localize a mobile RFID reader within a tagged environment. A software tool is developed to validate this localization process, …

Flexible Sigma Delta Time-Interleaved Bandpass Analog-To-Digital Converter, Ryan Edward Mcginnis

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Conversion of analog signals to their digital equivalent earlier in a circuit’s topology facilitates faster and more efficient exploitation of the information contained within. Analog-to-digital converters (ADCs) form the link between the analog and digital realms. In high frequency circuits ADCs must often be implemented further downstream after several stages of down-conversion, or through the use of more expensive technologies such as Bi-polar Junction Transistors or Gallium Arsenide. This thesis presents a technique to utilize Complimentary Metal Oxide Semiconductor technology in a parallel time-interleaved architecture. This will reduce circuit complexity and allow the ADC to be placed further upstream reducing …

Designing Computer Agents With Facial Personality To Improve Human-Machine Collaboration, Brian Esley Tidball

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The development of computer agents to enhance human-computer interfaces is an evolving field of study. This study examined whether people perceive personality in static digital faces that portray expressions of emotion, and if the digital faces would influence human performance on a simple human-machine collaborative task. The first experiment measured user-perception of personality, based on the emotional expression in two sets of five static digital faces. The results from this first phase revealed that participants provided different ratings, of the Big-Five personality model sub-traits, based on the emotional expression of a static digital face. This indicates a perception of personality …

Digital Channelized Wide Band Receiver Implemented With A Systolic Array Of Multi-Rate Fir Filters, David M. Rodney

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This thesis proposes the use of a Systolic Array of Multi-Rate FIR Filters to improve performance by eliminating the requirement of the FFT and De-Multiplexer associated with the conventional receiver while achieving the same functionality. The FFT is a major bottle neck for improving system performance for the conventional DCWBR because many complex multiplications and additions are required. The proposed new architecture is designed and evaluated in MATLAB to illustrate its viability. Two approaches for improved channel arbitration are accessed in MATLAB, namely, channel bin’s rms comparison and parallelism of the Systolic Array Multi-Rate FIR Filters. The FIR filters (high-pass …

Fpga Frequency Domain Based Gps Coarse Acquisition Processor Using Fft, Cyprian D. Sajabi

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The Global Positioning System or GPS is a satellite based technology that has gained widespread use worldwide in civilian and military applications. Direct Sequence Spread spectrum (DSSS) is the method whereby the data transmitted by the satellite and received by user is kept secure, low power and relatively noise-immune. The first step required in the GPS operation is to perform a lock on the incoming signal, both with respect to time synchronization and frequency resolution. Because of the need for reduced time to lock and also reduced hardware, algorithms based in the frequency domain have been developed. These algorithms take …

Human-Centered Time-Pressured Decision Making In Dynamic Complex Systems, Subhashini Ganapathy

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Many real-world applications are complex, dynamic, and uncertain. Human operators play an important role in ensuring the safety and in achieving operational effectiveness in such systems. During task performance, both humans and computerized processes bring in varying strengths and limitations. Research on human-centered automation in aviation, satellite ground control, and nuclear power plant control has resulted in broad guidelines on system design involving human and computerized processes in supervisory control. However, problems such as increased human error, lack of situational awareness, and opacity from poorly automated systems remain, particularly in scenarios where human operators must make decisions in time-pressured planning. …

Dissipated Energy At A Bimaterial Crack Tip Under Cyclic Loading, Jeremy S. Daily

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A new theory of fatigue crack growth in ductile solids has recently been proposed based on the total plastic energy dissipation per cycle ahead of the crack. This, and previous energy-based approaches in the literature, suggest that the total plastic dissipation per cycle can be closely correlated with fatigue crack growth rates under mode I loading. The goal of the current research is to extend the dissipated energy approach to steady-state crack growth under mixed-mode I/II loading conditions, with application to cyclic delamination of ductile bimaterial interfaces. Such systems can occur in brazing, soldering, welding, and a variety of layered …

Design And Evaluation Of A Discrete Wavelet Transform Based Multi-Signal Receiver, Tony Chiang

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General purpose receivers of today are designed with a broad bandwidth so that the receiver can accept a wide range of signal frequencies. These receivers usually accept one signal along with any interference that is included. To increase the signal detection capabilities of the wideband receiver, a design for a receiver that can detect two signals is needed. One of the requirements for this receiver is that the second weak signal needs to be processed in a timely manner so that the receiver can recognize it. To remedy the problem, a module was developed using wavelet-based techniques to remove spurs …

Fabrication Of Oxide Superconducting Thin Films Using Colloid Of Nanoparticles As Precursor, Vamsee K. Chintamaneni

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This thesis reports the development of a new approach for the fabrication of superconducting thin films. Among the liquid phase methods of fabricating high temperature superconductors having critical current density about 1 MA/cm², metalorganic deposition using metal trifluoroacetates (TFA-MOD) is the best known method. In this project, detailed spectroscopic and microscopic analysis was performed at every stage of the TFA-MOD process to understand the evolution of crystalline superconducting film. It was observed that the TFA-MOD has some inherent disadvantages such as long process time, evolution of HF gas and results porosity in films. A new liquid phase process …

Implementation Of A Multi-Layered Fuzzy Controller On An Fpga, Ajit Paal Singh Khatra

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The uses of Autonomous Mobile robots range from the teleoperated Sojourner on the Mars Pathfinder mission to cleaning robots in the Paris Metro. They have overtaken tasks which are too difficult or dangerous to perform or require the repetition of the same procedure over and over again and can become dull for a human to perform. The objective of this thesis is to develop and implement a multilayered fuzzy controller on an FPGA for the navigational control of an autonomous mobile robot (AMR). The navigational algorithm assists the robot in navigating through complex environments of passages and hallways. The FPGA …

Direct Digital Frequency Synthesizer Implementation Using A High Speed Rom Alternative In Ibm 0.13u Technology, Matthew R. Gerald

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The direct digital synthesizer is a method of signal generation with many benefits. DDS designs are able to switch frequencies very quickly and also tune precisely to many different frequencies with the use of a constant operating frequency. There is a need for a low power, high speed DDS in the form an ASIC design. One major bottleneck in common DDS systems is the slow access time of a ROM. There is also a need for a high speed ROM alternative. This thesis delivers a high speed ASIC Direct Digital Synthesizer which operates at a 1 GHz operating frequency. This …

Design Of A High-Power, High-Efficiency, Low-Distortion Direct From Digital Amplifier, Weston R. Earick

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For the process of converting low-power digital signals into their high-power analog counterparts, the functions of digital-to-analog conversion (at low power) and analog power amplification are separately implemented. This thesis proposes a new “STAC-DAC” circuit topology which directly realizes high-power analog output from low-power digital input signals. The ability to achieve a “direct from digital” high-power analog output in a single high-efficient, low-distortion design has significant potential in audio reproduction, and flexible signal generation applications. In this thesis, the “STAC-DAC” is described and its implementation via MATLAB and LTSpice is discussed. The results of simulations are used to prove the …

A Comparison Of Agent-Based Optimization Approaches Applied To The Weapons To Targets Assignment Planning Problem, Hitesh Deepak Soneji

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Real-world complex optimization problems are difficult to solve. Agent-based optimization approaches have proved useful in solving a wide variety of problems including optimization problems. Agent-based techniques can be used in military planning for solving allocation problems such as the weapons to targets assignment problem. Classical methods like linear programming (LP) have been used for solving weapons to targets assignment problems. LP approaches provide optimal solutions quickly, but in real-time planning when there are minor changes to input, LP exhibits widely varied solutions. This can be a problem in practice. This research study considers two agent-based optimization approaches, the Stable Marriage …

Regulation Of Dna Replication Initiation By Histone Acetylation And The Dna Unwinding Element Binding Protein Due-B, Michael George Kemp

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Duplication of the genome during S phase of the mitotic cell cycle begins at thousands of sites along chromosomes termed origins of replication. Although many of the essential protein components catalyzing events at these sites are known and are conserved throughout eukaryotes, the likelihood or efficiency of initiation of DNA synthesis at any given genomic site is expected to be influenced by other novel factors, including aspects of chromatin and DNA structure.

Here I show that increased histone H4 acetylation at replication origin loci occurs after treatment with the histone deacetylase inhibitor TSA and coincides with a loss of specific …

A Study Of The Impact Of Hardware Design Choices On The System Impulse Response Of A Signal-Level Radar Simulation, Kelly Renee Feirstine

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The main goal of this research is to study the effect of hardware design choices at the signal-level of an end-to-end radar system. An implementation of waveform diversity concepts, or the use of various waveforms in both transmit and receive is employed. An end-to-end Matlab simulation is developed such that the system impulse response to hardware imperfections and waveform parameters such as bandwidth and frequency channel spacing can be analyzed. Multiple frequency channels as well as multiple pulses are also considered in the research.

All hardware components are nonlinear to some degree. The nonlinearities of the hardware give rise to …

Characterizing Battlefield Human Decision Making With Value Focused Thinking And Reliability Modeling, Fawaz Al-Karaeen

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Military officers and soldiers in combat are faced with complex, time-critical decision problems. The battlefield, or combat, environment involves decisive operations under unpredictable and rapidly changing conditions. Decisions in battlefields take place under uncertain, time constrained conditions and in a tactical environment. A battlefield decision maker encounters a dynamic information environment. During combat, individuals gather and consider information from a variety of sources to determine what information is reliable and useful, and what information is not. There is a clear correlation between the decision making process and the value of information feeding that process. This research examines a decision making …

Robust Shape Design Techniques For Steady-State Metal Forming Processes, Jalaja Repalle

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Metal forming is a process that transforms a simple shape of a workpiece into a predetermined complex shape through the application of compressive/tensile forces exerted by dies. In the design of a forming process, the only factors that are known are the final component shape and the material with which it is to be made. Then the engineer has to design a process to make defect-free product, subject to limitations of shape, material properties, cost, time, and other such factors. The design cycle can be enhanced if performance sensitivity information is available that could be used with any commercially available …