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Articles 1 - 30 of 30
Full-Text Articles in Engineering
Development Of A Grond-Based High-Resolution 3d-Sar System For Studying The Microwave Scattering Characteristics Of Trees, Justin Frank Penner
Development Of A Grond-Based High-Resolution 3d-Sar System For Studying The Microwave Scattering Characteristics Of Trees, Justin Frank Penner
Theses and Dissertations
This thesis presents the development of a high-resolution ground-based 3D-SAR system and investigates its application to microwave-vegetation studies. The development process of the system is detailed including an enumeration of high-level requirements, discussions on key design issues, and detailed descriptions of the system down to a component level. The system operates on a 5.4 GHz (C-band) signal, provides a synthetic aperture area of 1.7 m x 1.7 m, and offers resolution of 0.75 m x 0.3 m x 0.3 m (range x azimuth x elevation). The system is employed on several trees with varying physical characteristics. The resulting imagery demonstrates …
Improved Stereo Vision Methods For Fpga-Based Computing Platforms, Wade S. Fife
Improved Stereo Vision Methods For Fpga-Based Computing Platforms, Wade S. Fife
Theses and Dissertations
Stereo vision is a very useful, yet challenging technology for a wide variety of applications. One of the greatest challenges is meeting the computational demands of stereo vision applications that require real-time performance. The FPGA (Field Programmable Gate Array) is a readily-available technology that allows many stereo vision methods to be implemented while meeting the strict real-time performance requirements of some applications. Some of the best results have been obtained using non-parametric stereo correlation methods, such as the rank and census transform. Yet relatively little work has been done to study these methods or to propose new algorithms based on …
Bonding Of Polydimethylsiloxane Microfluidics To Silicon-Based Sensors, Long-Fang Tsai, William C. Dahlquist, Seunghyun Kim, Gregory P. Nordin
Bonding Of Polydimethylsiloxane Microfluidics To Silicon-Based Sensors, Long-Fang Tsai, William C. Dahlquist, Seunghyun Kim, Gregory P. Nordin
Faculty Publications
We investigate bonding polydimethylsiloxane (PDMS) to silicon using a thin (~2μm) intermediate adhesive layer stamped onto a PDMS piece prior to bonding. In particular, we compare as adhesive layers Sylgard 184 and 182 curing agents and a UV curable adhesive (NOA 75). We examine the effect of both curing temperature and duration on curing agent bond strength. Bond strengths for the different adhesives are determined by measuring the average burst pressure at a PDMS-silicon interface using a PDMS test design. We find that Sylgard 184 curing agent gives the highest bond strength with burst pressure of 700 kPa or more …
Bearing-Only Cooperative-Localization And Path-Planning Of Ground And Aerial Robots, Rajnikant Sharma
Bearing-Only Cooperative-Localization And Path-Planning Of Ground And Aerial Robots, Rajnikant Sharma
Theses and Dissertations
In this dissertation, we focus on two fundamental problems related to the navigation of ground robots and small Unmanned Aerial Vehicle (UAVs): cooperative localization and path planning. The theme running through in all of the work is the use of bearing only sensors, with a focus on monocular video cameras mounted on ground robots and UAVs. To begin with, we derive the conditions for the complete observability of the bearing-only cooperative localization problem. The key element of this analysis is the Relative Position Measurement Graph (RPMG). The nodes of an RPMG represent vehicle states and the edges represent bearing measurements …
Fpga Bootstrapping Using Partial Reconfiguration, Patrick Sutton Ostler
Fpga Bootstrapping Using Partial Reconfiguration, Patrick Sutton Ostler
Theses and Dissertations
Partial reconfiguration (PR) is the process of configuring a subset of resources on a Field Programmable Gate Array (FPGA) while the remainder of the device continues to operate. PR extends the usability of FPGAs and makes it possible to perform design bootstrapping. Just like bootstrapping in PCs, bootstrapping in FPGAs consists of using a small application to initialize basic services and load a larger, more complex application to the device. Bootstrapping allows for unique design applications that can be used to maintain communication services, increase design security, reduce initial configuration time, and reduce nonvolatile configuration memory storage. This thesis presents …
The Pulled-Macro-Dataflow Model: An Execution Model For Multicore Shared-Memory Computers, Daniel Joseph Richins
The Pulled-Macro-Dataflow Model: An Execution Model For Multicore Shared-Memory Computers, Daniel Joseph Richins
Theses and Dissertations
The macro-dataflow model of execution has been used in scheduling heuristics for directed acyclic graphs. Since this model was developed for the scheduling of parallel applications on distributed computing systems, it is inadequate when applied to the multicore shared-memory computers prevalent in the market today. The pulled-macro-dataflow model is put forth as an alternative to the macro-dataflow model, having been designed specifically to accurately describe the memory bandwidth limitations and request-driven nature of communications characteristic of today's machines. The performance of the common scheduling heuristics DSC and CASS-II are evaluated under the pulled-macro-dataflow model and it is shown that their …
Vision-Based Path Planning, Collision Avoidance, And Target Tracking For Unmanned Air And Ground Vehicles In Urban Environments, Huili Yu
Theses and Dissertations
Unmanned vehicle systems, specifically Unmanned Air Vehicles (UAVs) and Unmanned Ground Vehicles (UGVs) have found potential use in both military and civilian applications. For many applications, unmanned vehicle systems are required to navigate in urban environments where obstacles with various types and sizes exist. The main contribution of this research is to offer vision-based path planning, collision avoidance, and target tracking strategies for Unmanned Air and Ground vehicles operating in urban environments. Two vision-based local-level frame mapping and planning techniques are first developed for Miniature Air Vehicles (MAVs). The techniques build maps and plan paths in the local-level frame of …
Active Impedance Matching And Sensitivity Optimized Phased Array Feed Design For Radio Astronomy, David E. Carter
Active Impedance Matching And Sensitivity Optimized Phased Array Feed Design For Radio Astronomy, David E. Carter
Theses and Dissertations
One of the many challenges in radio astronomy is the ability to make accurate measurements quickly. In recent years engineers and astronomers have begun implementing phased array feeds (PAFs) as a way to negate the long observation times required by single antenna feeds. Unfortunately, large mutual coupling and other loss terms result in low sensitivity, restricting PAF usefulness in on dish observation. This thesis addresses several ways to reduce mutual coupling and maximize sensitivity for PAFs in radio astronomy. Antenna design of this magnitude requires accurate modeling capabilities. To this end, electromagnetic software models and low loss component designs are …
Tailoring The Spectral Transmission Of Optofluidic Waveguides, Brian S. Phillips
Tailoring The Spectral Transmission Of Optofluidic Waveguides, Brian S. Phillips
Theses and Dissertations
Optofluidics is a relatively new and exciting field that includes the integration of optical waveguides into microfluidic platforms. The purpose of this field of study is to miniaturize previously developed optical systems used for biological and chemical analysis with the end goal of placing bench-top optics into microscopic packages. Mundane optical alignment and sample manipulation procedures would then be intrinsic to the platform and allow measurements to be completed quickly and with reduced human interaction. Biosensors based on AntiResonant Reflecting Optical Waveguides (ARROWs) consist of hollow-core waveguides used for fluid sample manipulation and analysis, as well as solid-core waveguides used …
Automated Fixed-Point Analysis And Bit Width Selection In Digital Signal Processing Circuits Using Ptolemy, Derrick S. Gibelyou
Automated Fixed-Point Analysis And Bit Width Selection In Digital Signal Processing Circuits Using Ptolemy, Derrick S. Gibelyou
Theses and Dissertations
When designing custom hardware to implement signal processing algorithms, it is important to select bitwidths that meet the minimum error requirements while minimizing implementation area. Larger bitwidths reduce error, but increase area, while selecting smaller bitwidths does the opposite. Finding the set of bitwidths that produces the smallest area that still meets the error requirements has been shown to be NP-hard. To address this problem, many heuristics have been developed. Unfortunately, they are not always well documented and do not have available source code. It is also di cult to know which algorithm to try to use. This thesis addresses …
Development Of An Experimental Phased-Array Feed System And Algorithms For Radio Astronomy, Jonathan Charles Landon
Development Of An Experimental Phased-Array Feed System And Algorithms For Radio Astronomy, Jonathan Charles Landon
Theses and Dissertations
Phased array feeds (PAFs) are a promising new technology for astronomical radio telescopes. While PAFs have been used in other fields, the demanding sensitivity and calibration requirements in astronomy present unique new challenges. This dissertation presents some of the first astronomical PAF results demonstrating the lowest noise temperature and highest sensitivity at the time (66 Kelvin and 3.3 m^2/K, respectively), obtained using a narrowband (425 kHz bandwidth) prototype array of 19 linear co-polarized L-band dipoles mounted at the focus of the Green Bank 20 Meter Telescope at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia. Results include …
Robust Signaling, Scheduling And Authentication In The Multi-User Multiple-Input-Multiple-Output Channel, Yan Shi
Theses and Dissertations
Multiple-input multiple-output (MIMO) networks are known to be able to achieve throughput performance superior to that available from single-input single-output (SISO) systems. However, when applying MIMO in multi-user networks, achieving this throughput advantage requires efficient precoding and optimal network scheduling. Furthermore, MIMO radios can help ensure security in a multi-user network. Previous work has proposed various precoding techniques for the MIMO broadcast channel, based either on channel state information (CSI) or channel distribution information (CDI), which achieve optimal or near- optimal MIMO channel throughput. The performance of these techniques largely depends on the availability of the channel information at the …
Fpga Communication Framework For Communication, Debugging, Testing, And Rapid Prototyping, Peter Andrew Lieber
Fpga Communication Framework For Communication, Debugging, Testing, And Rapid Prototyping, Peter Andrew Lieber
Theses and Dissertations
FPGA-CF is an open-source, portable, extensible communications framework that consists of a small hardware core (less than 600 slices) and a software library/API (Java and C++). It enables a host PC to transmit data at 120 Mb/s to Xilinx-based FPGA boards via Ethernet using standard inter-networking protocols (UDP/IP). A custom lightweight connection-oriented protocol guarantees reliability. The hardware core is directly connected to the Xilinx internal configuration port (ICAP) and supports all ICAP functionality. The core also provides an extensible user-channel interface and provides up to 15, 8-bit user-data channels that can be connected to user circuitry (configurable by the user). …
Magnetic Field Sensing With Slab Coupled Optical Fiber Sensors, Bryson J. Shreeve
Magnetic Field Sensing With Slab Coupled Optical Fiber Sensors, Bryson J. Shreeve
Theses and Dissertations
This thesis reports an in-fiber magnetic field sensor that is able to detect magnetic fields as low as 2 A/m at a spatial resolution of 1 mm. The small sensor consists of a magneto-optic slab waveguide, bismuth-doped rare earth iron garnet (Bi-RIG) that is coupled to an optical fiber. By coupling light from the fiber to the slab waveguide, it becomes an in-fiber magnetic field sensor. This is due to the Magneto-Optic Kerr effect; a change in refractive index is proportional to the applied magnetic field. When an AC field is applied, an AC component in the output power can …
Integration Of Micropore And Nanopore Features With Optofluidic Waveguides For Single Particle Sensing, Matthew R. Holmes
Integration Of Micropore And Nanopore Features With Optofluidic Waveguides For Single Particle Sensing, Matthew R. Holmes
Theses and Dissertations
This dissertation outlines the research and development of ground-breaking nanometer sized openings (nanopores) integrated with an on-chip optofluidic platform. This platform represents a significant advancement for single nanoparticle sensing. In this work specifically, the integrated optofluidic platform has been used to electrically and optically filter and detect single nanoparticles using ionic current blockade and fluorescence experiments. The correlation of electrical and optical signal has provided the highest sensitivity single nanoparticle measurements ever taken with integrated optofluidic platforms. The particular optofluidic platform used for this work is an antiresonant reflecting optical waveguide (ARROW). ARROW hollow and solid core waveguides are interference …
A Wideband Precision Quadrature Phase Shifter, Steve T. Noall
A Wideband Precision Quadrature Phase Shifter, Steve T. Noall
Theses and Dissertations
A new circuit is proposed that uses an RC-CR filter in a feedback configuration to achieve a wideband precision quadrature phase shift with constant amplitude response. Such a circuit can be used to perform image rejection in a low IF receiver using the Hartley method. Simulation results show that the circuit can achieve an average image rejection ratio of 50 dB over a 16 MHz bandwidth. The feedback loop enables the circuit to maintain high accuracy over process and temperature.
Multi-Year Arctic Sea Ice Classification Using Quikscat, Aaron M. Swan
Multi-Year Arctic Sea Ice Classification Using Quikscat, Aaron M. Swan
Theses and Dissertations
Long term trends in Arctic sea ice are of particular interest with regard to global temperature, climate change, and industry. This thesis uses microwave scatterometer data from QuikSCAT and radiometer data to analyze intra- and interannual trends in first-year and multi-year Arctic sea ice. It develops a sea ice type classification method. The backscatter of first-year and multi-year sea ice are clearly identifiable and are observed to vary seasonally. Using an average of the annual backscatter trends obtained from QuikSCAT, a classification of multi-year ice is obtained which is dependent on the day of the year (DOY). Validation of the …
Byu Indoor Flight System Circa June 2011, John C. Macdonald, Robert Leishman
Byu Indoor Flight System Circa June 2011, John C. Macdonald, Robert Leishman
Faculty Publications
This report documents the state of our indoor flight platform as of June 2011, the time of its first flight without a human in the loop. The report is intended to give enough detail that someone might have a reasonable hope of replicating our work from scratch.
Observability Analysis Of Cooperative Localization Using Graph Theory And Lie Derivatives, Rajnikant Sharma
Observability Analysis Of Cooperative Localization Using Graph Theory And Lie Derivatives, Rajnikant Sharma
Faculty Publications
In this report we derive the observability matrix for an edge between two robots and an edge between a robot and a landmark.
Advancements In The Solid-State Impact-Ionization Multiplier (Sim) Through Theory, Simulation And Design, Michael S. Johnson
Advancements In The Solid-State Impact-Ionization Multiplier (Sim) Through Theory, Simulation And Design, Michael S. Johnson
Theses and Dissertations
This dissertation outlines the study and development of a Solid-state Impact-ionization Multiplier (SIM). The SIM is a stand-alone current amplifier designed with optical detection systems in mind. The SIM amplifies signals utilizing impact ionization as a source of gain. The SIM is fabricated on silicon in order to take advantage of its favorable impact ionization coefficients. Utilizing silicon in impact ionization based gain devices makes low noise and high gains attainable. Because it is a stand-alone device, it can be wired to an arbitrary current source making it capable of receiving an input from photodiodes of any material. This makes …
Fm Demodulators In Software-Defined Radio Using Fpgas With Rapid Prototyping, Marc Anthony Padilla
Fm Demodulators In Software-Defined Radio Using Fpgas With Rapid Prototyping, Marc Anthony Padilla
Theses and Dissertations
With the advent of software-defined radio, many radio applications have and are currently being designed for FPGAs, due to their high performance and reconfigurability. Invariably, "legacy" waveforms, such as FM, will need to be supported in such systems. A challenge that comes with programming FPGAs is the increased design and implementation time over conventional software programming. In this thesis, three FM demodulator techniques are implemented and compared in an FPGA. Two techniques are found to have similar SNR performance while having very different FPGA implementation characteristics. Library based design is explored for demodulators to increase FPGA design productivity. A block …
Development Of Single-Chip Silicon Photonic Microcantilever Arrays For Sensing Applications, Weisheng Hu
Development Of Single-Chip Silicon Photonic Microcantilever Arrays For Sensing Applications, Weisheng Hu
Theses and Dissertations
Microcantilever arrays have been shown to be promising label-free nanomechanical sensing devices with high sensitivity. Two factors that affect the usefulness of microcantilevers in sensing scenarios are the sensitivity of the transduction method for measuring changes in microcantilever properties and the ability to create large compact arrays of microcantilevers. In this dissertation, we demonstrate that microcantilevers with an in-plane photonic transduction method are attractive because they maintain the sensitivity of the traditional laser beam reflection method while being scalable to simultaneous readout of large microcantilever arrays. First I demonstrate the integration of a compact waveguide splitter network with in-plane photonic …
Increasing Design Productivity For Fpgas Through Ip Reuse And Meta-Data Encapsulation, Adam T. Arnesen
Increasing Design Productivity For Fpgas Through Ip Reuse And Meta-Data Encapsulation, Adam T. Arnesen
Theses and Dissertations
As Moore's law continues to progress, it is becoming increasingly difficult for hardware designers to fully utilize the increasing number of transistors available semiconductor devices including FPGAs. This design productivity gap must be addressed to allow designs to take full advantage of the increased logic density that results from rising transistor density. The reuse of previously developed and verified intellectual property (IP) is one approach that has claimed to narrow the design productivity gap. Reuse, however, has proved difficult to realize in practice because of the complexity of IP and the reluctance of designers to reuse IP that they do …
Fiber Optic Sensor Interrogation Advancements For Research And Industrial Use, Wesley Mont Kunzler
Fiber Optic Sensor Interrogation Advancements For Research And Industrial Use, Wesley Mont Kunzler
Theses and Dissertations
Spectrally-based fiber optic sensors are a rapidly maturing technology capable of sensing several environmental parameters in environments that are unfitting to electrical sensors. However, the sensor interrogation systems for this type of sensors are not yet fit to replace conventional sensor systems. They lack the speed, compact size, and usability necessary to move into mainstream test and measurement. The Fiber Sensor Integrated Monitor (FSIM) technology leverages rapid optical components and parallel hardware architecture to move these sensors across the research threshold into greater mainstream use. By dramatically increasing speed, shrinking size, and targeting an interface that can be used in …
A High-Gain, Low-Power Cmos Operational Amplifier Using Composite Cascode Stage In The Subthreshold Region, Rishi Pratap Singh
A High-Gain, Low-Power Cmos Operational Amplifier Using Composite Cascode Stage In The Subthreshold Region, Rishi Pratap Singh
Theses and Dissertations
This thesis demonstrates that the composite cascode differential stage, operating in the subthreshold region, can form the basis of a high gain (113 dB) and low-power op amp (28.1 µW). The circuit can be fabricated without adding a compensation capacitance. The advantages of this architecture include high voltage gain, low bandwidth, low harmonic distortion, low quiescent current and power, and small chip area. These advantages suggest that this design might be well-suited for biomedical applications where low power, low noise bio-signal amplifiers capable of amplifying signals in the millihertz-to-kilohertz range is required.
System Identification, State Estimation, And Control Of Unmanned Aerial Robots, Caleb H. Chamberlain
System Identification, State Estimation, And Control Of Unmanned Aerial Robots, Caleb H. Chamberlain
Theses and Dissertations
This thesis describes work in a variety of topics related to aerial robotics, including system identification, state estimation, control, and path planning. The path planners described in this thesis are used to guide a fixed-wing UAV along paths that optimize the aircraft's ability to track a ground target. Existing path planners in the literature either ignore occlusions entirely, or they have limited capability to handle different types of paths. The planners described in this thesis are novel in that they specifically account for the effect of occlusions in urban environments, and they can produce a much richer set of paths …
Xdl-Based Hard Macro Generator, Subhrashankha Ghosh
Xdl-Based Hard Macro Generator, Subhrashankha Ghosh
Theses and Dissertations
In a conventional hardware design flow, the compilation process to create the physical circuit on the FPGA takes a long time. HMFlow is a design flow that reduces the compilation time by using pre-compiled modules called hard macros. HMFlow uses System Generator to create the designs, which are then converted to hard macros. The hard macro creation process takes a long time and a possible solution is a hard macro generator called XdlCoreGen, which is described in this thesis. XdlCoreGen can quickly create fully mapped and placed hard macros using XDL. XDL is a human readable design format that describes …
Analysis And Mitigation Of Seu-Induced Noise In Fpga-Based Dsp Systems, Brian Hogan Pratt
Analysis And Mitigation Of Seu-Induced Noise In Fpga-Based Dsp Systems, Brian Hogan Pratt
Theses and Dissertations
This dissertation studies the effects of radiation-induced single-event upsets (SEUs) on digital signal processing (DSP) systems designed for field-programmable gate arrays (FPGAs). It presents a novel method for evaluating the effects of radiation on DSP and digital communication systems. By using an application-specific measurement of performance in the presence of SEUs, this dissertation demonstrates that only 5-15% of SEUs affecting a communications receiver (i.e. 5-15% of sensitive SEUs) cause critical performance loss. It also reports that the most critical SEUs are those that affect the clock, global reset, and most significant bits (MSBs) of computation. This dissertation also demonstrates …
On-Orbit Fpga Seu Mitigation And Measurement Experiments On The Cibola Flight Experiment Satellite, William A. Howes
On-Orbit Fpga Seu Mitigation And Measurement Experiments On The Cibola Flight Experiment Satellite, William A. Howes
Theses and Dissertations
This work presents on-orbit experiments conducted to validate SEU mitigation and detection techniques on FPGA devices and to measure SEU rates in FPGAs and SDRAM. These experiments were designed for the Cibola Flight Experiment Satellite (CFESat), which is an operational technology pathfinder satellite built around 9 Xilinx Virtex FPGAs and developed at Los Alamos National Laboratory. The on-orbit validation experiments described in this work have operated for over four thousand FPGA device days and have validated a variety of SEU mitigation and detection techniques including triple modular redundancy, duplication with compare, reduced precision redundancy, and SDRAM and FPGA block memory …
A Correlation-Based Method To Detect Weak Dependence, Yabing Luo
A Correlation-Based Method To Detect Weak Dependence, Yabing Luo
Theses and Dissertations
The focus of this thesis is an investigation of ways to detect weak dependence between two random variables X and Y. Our approach is to design tests for correlation rather than testing for dependence directly, since X and Y are not independent if they are not uncorrelated. We examined the magnified Pearson correlation after the Box-Cox transformation to determine whether X and Y are dependent. The results indicated that our approach not only has the potential to detect and evaluate the weak dependence cases that have previously been intractable, but also is conceptually simple and easy to implement.