Engineering Commons^™

Novel Mobile Computation Offloading Framework For Android Devices, Meng Wang

McKelvey School of Engineering Theses & Dissertations

The thesis implements an offloading framework for GoogleTM AndroidTM based on mobile devices. Today, the full potential for smartphones may be constrained by certain technical limits such as battery endurance and computational performance. Modern mobile applications own more powerful functions but need larger computation and faster frame rate, which consume more battery energy. Using the proposed offloading framework, mobile devices can offload computational intensive workload to servers to save battery energy consumption and reduce the execution time. The framework can also enable software developers to easily build and deploy services on the servers to support mobile devices to run computationally …

Real-Time Temperature Imaging Using Ultrasonic Change In Backscattered Energy, Weiyuan Zhao

McKelvey School of Engineering Theses & Dissertations

Thermal therapy from low-temperature cryosurgery to high-temperature ablation of tumors and unwanted electrical pathways has gained increased attention. Temperature imaging (TI) from magnetic resonance studies is the de facto standard for volumetric estimation of temperature. Ultrasound has the advantages of being cheap, portable, non-invasive and non-ionizing. Our group showed in predictions for single scatterers, simulations of scatterer populations and measurements in 1D, 2D and 3D, that CBE changed monotonically with temperature with 1^oC accuracy. An obstacle to clinical application of CBE TI is estimation of temperature in real time, which is limited by time for motion compensation (MC). …

Ultrasound-Mediated Optical Imaging And Focusing In Scattering Media, Yuta Suzuki

McKelvey School of Engineering Theses & Dissertations

Because of its non-ionizing and molecular sensing nature, light has been an attractive tool in biomedicine. Scanning an optical focus allows not only high-resolution imaging but also manipulation and therapy. However, due to multiple photon scattering events, conventional optical focusing using an ordinary lens is limited to shallow depths of one transport mean free path (lt'), which corresponds to approximately 1 mm in human tissue.

To overcome this limitation, ultrasonic modulation (or encoding) of diffuse light inside scattering media has enabled us to develop both deep-tissue optical imaging and focusing techniques, namely, ultrasound-modulated optical tomography (UOT) and time-reversed ultrasonically encoded …

Contextualized Robot Navigation, David Vincent Lu

McKelvey School of Engineering Theses & Dissertations

In order to improve the interaction between humans and robots, robots need to be able to move about in a way that is appropriate to the complex environments around them. One way to investigate how the robots should move is through the lens of theatre, which provides us with ways to analyze the robot's movements and the motivations for moving in particular ways. In particular, this has proven useful for improving robot navigation. By altering the costmaps used for path planning, robots can navigate around their environment in ways that incorporate additional contexts. Experimental results with user studies have shown …

Real-Time And Energy-Efficient Routing For Industrial Wireless Sensor-Actuator Networks, Chengjie Wu

McKelvey School of Engineering Theses & Dissertations

With the emergence of industrial standards such as WirelessHART, process industries are adopting Wireless Sensor-Actuator Networks (WSANs) that enable sensors and actuators to communicate through low-power wireless mesh networks. Industrial monitoring and control applications require real-time communication among sensors, controllers and actuators within end-to-end deadlines. Deadline misses may lead to production inefficiency, equipment destruction to irreparable financial and environmental impacts. Moreover, due to the large geographic area and harsh conditions of many industrial plants, it is labor-intensive or dan- gerous to change batteries of field devices. It is therefore important to achieve long network lifetime with battery-powered devices.

This dissertation …

Accelerating Heuristic Search For Ai Planning, You Xu

McKelvey School of Engineering Theses & Dissertations

AI Planning is an important research field. Heuristic search is the most commonly used method in solving planning problems. Despite recent advances in improving the quality of heuristics and devising better search strategies, the high computational cost of heuristic search remains a barrier that severely limits its application to real world problems. In this dissertation, we propose theories, algorithms and systems to accelerate heuristic search for AI planning.

We make four major contributions in this dissertation. First, we propose a state-space reduction method called Stratified Planning to accelerate heuristic search. Stratified Planning can be combined with any heuristic search to …

Approximation And Relaxation Approaches For Parallel And Distributed Machine Learning, Stephen Tyree

McKelvey School of Engineering Theses & Dissertations

Large scale machine learning requires tradeoffs. Commonly this tradeoff has led practitioners to choose simpler, less powerful models, e.g. linear models, in order to process more training examples in a limited time. In this work, we introduce parallelism to the training of non-linear models by leveraging a different tradeoff--approximation. We demonstrate various techniques by which non-linear models can be made amenable to larger data sets and significantly more training parallelism by strategically introducing approximation in certain optimization steps.

For gradient boosted regression tree ensembles, we replace precise selection of tree splits with a coarse-grained, approximate split selection, yielding both faster …

Toward Improved Computational Tools For Electronic Transport Analysis And Their Use In The Development Of Materials For Energy Applications, Maria Stoica

McKelvey School of Engineering Theses & Dissertations

With the rapid rise in computational speed and capacity of massively parallel computing clusters in recent years, theoretical screening of large, previously unexplored sets of complex compounds to find materials with a given set of desired properties is quickly becoming a reality. In order to maximize the predictive ability of these large-scale computations, it is desirable to develop accurate post-processing algorithms that can efficiently manipulate electronic structure data to produce theoretical predictions of experimentally observable quantities. To address this need, the work of this dissertation has been to expand existing \textit{ab initio} methods for determining electronic properties of bulk complex …

Joint Representation Of Translational And Rotational Components Of Self-Motion In The Parietal Cortex, Adhira Sunkara

McKelvey School of Engineering Theses & Dissertations

Navigating through the world involves processing complex visual inputs to extract information about self-motion relative to one's surroundings. When translations (T) and rotations (R) are present together, the velocity patterns projected onto the retina (optic flow) are a combination of the two. Since navigational tasks can be extremely varied, such as deciphering heading or tracking moving prey or estimating one's motion trajectory, it is imperative that the visual system represent both the T and R components. Despite the importance of such joint representations, most previous studies have only focused on the representation of translations. Moreover, these studies emphasized the role …

The Synchronized Filtering Dataflow, Peng Li

McKelvey School of Engineering Theses & Dissertations

In the past decade, the world has seen the rise of big data, which calls for a paradigm shift in data processing. Streaming processing, where data are processed in their spatial or temporal order, is increasingly common. Meanwhile, parallel computing has become a household term in the computing world. The combination of streaming processing and parallel computing, streaming computing, has been playing an important role in data processing.

A streaming computing system is a network of nodes connected by unidirectional first-in first-out (FIFO) data channels. When a node has multiple input channels, to ensure the deterministic behavior of the whole …

A Four-Dimensional Image Reconstruction Framework For Pet Under Arbitrary Geometries, Aswin John Mathews

McKelvey School of Engineering Theses & Dissertations

Positron Emission Tomography (PET) is a functional imaging modality with applications ranging from the treatment of cancer, studying neurological diseases and disease models. Virtual-Pinhole PET technology improves the image quality in terms of resolution and contrast recovery. The technology calls for having a detector with smaller crystals placed near a region of interest in a conventional whole-body PET scanner. The improvement is from the higher spatial sampling of the imaging area near the detector. A prototype half-ring PET insert built to study head-and-neck cancer imaging was extended to breast cancer imaging. We have built a prototype half-ring PET insert for …

Aerosol Techniques For Deposition And Characterization Of Biological And Biomimetic Sensitizers For Solar Devices, Vivek B. Shah

McKelvey School of Engineering Theses & Dissertations

Nano-structured columnar films synthesized by the aerosol chemical vapor deposition (ACVD) system are unique, and have proved to be useful for fabricating solar cells and in other applications. The film formation by ACVD process involves three main phenomenon - aerosol formation and growth, deposition, and restructuring. In this work, thin film formation by the ACVD process is simulated by combining three models - (A) particle formation in gas phase by atrimodal model, (B) particle deposition onto heated substrate by a Brownian dynamics model and (C) sintering on the heated substrate by a multi-particle geometric sintering model (MPGSM). Modelling and simulation …

A Reinforcement-Learning Framework For Interpreting Trial-By-Trial Motor Adaptation To Novel Haptic Environments, Ranjan Patrick Khan

McKelvey School of Engineering Theses & Dissertations

Motor adaptation is often considered to occur under the influence of sensory signals, which is usually readily available for humans performing most motor tasks. However, humans can also use reward or other qualitative feedback to reinforce previous actions and perform adaptation. In these experiments, we introduce reward feedback to a traditional motor adaptation experiment: reach adaptation to a velocity-dependent force field. Drawing from the literature of computer science and machine learning, we use a reinforcement-learning framework to interpret the pattern of force generation and reward-prediction errors and observe the effects of concurrent and isolated reward and sensory feedback.

It is …

Modeling Algorithm Performance On Highly-Threaded Many-Core Architectures, Lin Ma

McKelvey School of Engineering Theses & Dissertations

The rapid growth of data processing required in various arenas of computation over the past decades necessitates extensive use of parallel computing engines. Among those, highly-threaded many-core machines, such as GPUs have become increasingly popular for accelerating a diverse range of data-intensive applications. They feature a large number of hardware threads with low-overhead context switches to hide the memory access latencies and therefore provide high computational throughput. However, understanding and harnessing such machines places great challenges on algorithm designers and performance tuners due to the complex interaction of threads and hierarchical memory subsystems of these machines. The achieved performance jointly …

Metabolic Engineering Of Cyanobacteria For Photosynthetic Production Of Drop-In Liquid Fuels, Bertram Michael Berla

McKelvey School of Engineering Theses & Dissertations

Cyanobacteria are oxygenic phototrophs with great potential as hosts for renewable fuel and chemical production. They grow very quickly (compared with plants) and can use sunlight for energy and CO2 as a carbon source (unlike yeast or E. coli). While cyanobacteria have been engineered to make many chemicals that are native and non-native parts of their metabolism, this work is concerned with the production of heptadecane in Synechocystis sp. PCC 6803. Heptadecane is in a class of natural products produced by all cyanobacteria, but in quantities insufficient for industrialization. Towards this future goal, we have built enabling systems for the …

Restoring Upper Extremity Mobility Through Functional Neuromuscular Stimulation Using Macro Sieve Electrodes, Erik R. Zellmer

All Theses and Dissertations (ETDs)

The last decade has seen the advent of brain computer interfaces able to extract precise motor intentions from cortical activity of human subjects. It is possible to convert captured motor intentions into movement through coordinated, artificially induced, neuromuscular stimulation using peripheral nerve interfaces. Our lab has developed and tested a new type of peripheral nerve electrode called the Macro-Sieve electrode which exhibits excellent chronic stability and recruitment selectivity. Work presented in this thesis uses computational modeling to study the interaction between Macro-Sieve electrodes and regenerated peripheral nerves. It provides a detailed understanding of how regenerated fibers, both on an individual …

Image Reconstruction In Photoacoustic Computed Tomography With Acoustically Heterogeneous Media, Chao Huang

All Theses and Dissertations (ETDs)

Photoacoustic computed tomography (PACT), also known as optoacoustic or thermoacoustic tomography, is a rapidly emerging hybrid imaging modality that combines optical image contrast with ultrasound detection. The majority of currently available PACT image reconstruction algorithms are based on idealized imaging models that assume a lossless and acoustically homogeneous medium. However, in many applications of PACT these assumptions are violated and the induced photoacoustic (PA) wavefields are scattered and absorbed as they propagate to the receiving transducers. In those applications of PACT, the reconstructed images can contain significant distortions and artifacts if the inhomogeneous acoustic properties of the object are not …

Engineering Biosensors For Short-Chain Alcohols, Yu Xia

McKelvey School of Engineering Theses & Dissertations

Biofuel is a promising substitute for fossil fuel and the research of biofuel production has been extensively conducted during the recent years. Great efforts have been made to create many types of the fuel production hosts. However, effective approaches for high specificity and high throughput screening of the fuel production strains are still lacking. The cellular stress response is one universal defense mechanism when a microbial cell is exposed to an unfavorable substance or environment. It triggers a series of downstream responses when a cell senses certain chemicals. Transcriptional factors are widely used in living organisms to regulate gene expression. …

Evaluation Of The Performance Of Various Turbulence Models For Accurate Numerical Simulation Of A 2d Slot Nozzle Ejector, Colin Graham

McKelvey School of Engineering Theses & Dissertations

With the development over the last several decades, accurate Computational Fluid Dynamics (CFD) modeling has now become an essential part in the analysis and design of various industrial products where the fluid flow plays an important role. The goal of this thesis is to apply the CFD technology to the analysis of a 2D slot nozzle ejector which has application in Short Take-off and Landing (STOL) aircraft and other future aerospace vehicles. In the nozzle-ejector configuration, the high speed air flow from the nozzle entrains the ambient air into a mixing chamber (ejector) as a means to create additional thrust …

Single Cuo Nanowires Electrical Properties And Application On Photoelectrochemical Water Splitting, Junnan Wu

McKelvey School of Engineering Theses & Dissertations

Charge transport in single crystal, p type copper oxide (CuO) nanowires (NWs) was studied through temperature based (120 K – 400 K) current-voltage (I-V) measurements of 2-terminal single NW devices. Individual CuO NWs with an average diameter of 220 nm were attached to Au electrodes 2.5 µm apart, using a dielectrophoresis method. I-V curves showed a transition from linear behavior at low bias to strong power law dependence (I ~ V^a) at high bias, which can be attributed to space charge limited current (SCLC) mechanism. At low electrical fields (< 0.89 × 10³ V·cm^-1), the number of …

Shape Optimization Of Airfoils Without And With Ground Effect Using A Multi-Objective Genetic Algorithm, Yilei He

McKelvey School of Engineering Theses & Dissertations

The focus of this thesis is on shape optimization using a genetic algorithm. A multi-objective genetic algorithm (MOGA) is employed to optimize the shape of an airfoil to improve its lift and drag characteristics, in particular to achieve two objectives simultaneously that is to increase its lift as well as its lift to drag ratio. The commercially available software FLUENT is employed to calculate the flow field on an adaptive structured mesh, which is generated by the commercial mesh generating software ICEM. The flow field is calculated using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a two equation k-ω …

Optical Resonators And Fiber Tapers As Transducers For Detection Of Nanoparticles And Bio-Molecules, Huzeyfe Yilmaz

McKelvey School of Engineering Theses & Dissertations

In recent years, detection of biological interactions on single molecule level has aspired many researchers to investigate several optical, chemical, electrical and mechanical sensing tools. Among these tools, toroidal optical resonators lead the way in detection of the smallest particle/molecule with the real time measurements. In this work, bio-sensing capabilities of toroidal optical resonators are investigated. Bio-sensing is realized via measuring the analyte-antigen interaction while the antigen is immobilized through a novel functionalization method.

Not long ago, detection of single nanoparticles using optical resonators has been accomplished however the need for cost-effective and practical transducers demands simpler tools. A tapered …

Detection Of Parkinson Disease Rest Tremor, Matthew J. Johnson

McKelvey School of Engineering Theses & Dissertations

Parkinson Disease (PD) is a debilitating and progressive movement disorder that is estimated to affect over six million worldwide. One of the most characteristic symptoms of PD is resting tremor, which involves unintentional and rhythmic muscle oscillations of an afflicted extremity while the muscles of said extremity are relaxed. This study involved measuring the rest tremor of 10 PD subjects, 10 Essential Tremor subjects, and 10 healthy control subjects using two devices. One device was an FDA approved accelerometry system to measure human tremor known as the Tremorometer^TM and the other was a consumer three-dimensional camera known as the …

Modeling And Development Of Iterative Reconstruction Algorithms In Emerging X-Ray Imaging Technologies, Jiaofeng Xu

All Theses and Dissertations (ETDs)

Many new promising X-ray-based biomedical imaging technologies have emerged over the last two decades. Five different novel X-ray based imaging technologies are discussed in this dissertation: differential phase-contrast tomography (DPCT), grating-based phase-contrast tomography (GB-PCT), spectral-CT (K-edge imaging), cone-beam computed tomography (CBCT), and in-line X-ray phase contrast (XPC) tomosynthesis. For each imaging modality, one or more specific problems prevent them being effectively or efficiently employed in clinical applications have been discussed. Firstly, to mitigate the long data-acquisition times and large radiation doses associated with use of analytic reconstruction methods in DPCT, we analyze the numerical and statistical properties of two classes …

Engineered Plasmonic Nanostructures For Nanomedicine, Christopher Matthew Portz

McKelvey School of Engineering Theses & Dissertations

No abstract provided.

Numerical Simulation And Optimization Of Carbon Dioxide Utilization And Storage In Enhanced Gas Recovery And Enhanced Geothermal Systems, James H. Biagi

McKelvey School of Engineering Theses & Dissertations

With rising concerns surrounding CO₂ emissions from fossil fuel power plants, there has been a strong emphasis on the development of safe and economical Carbon Capture Utilization and Storage (CCUS) technology. Two methods that show the most promise are Enhanced Gas Recovery (EGR) and Enhanced Geothermal Systems (EGS). In Enhanced Gas Recovery a depleted or depleting natural gas reservoir is re-energized with high pressure CO₂ to increase the recovery factor of the gas. As an additional benefit following the extraction of natural gas, the reservoir would serve as a long-term storage vessel for the captured carbon. CO_{2 …}

Global Edf Scheduling For Parallel Real-Time Tasks, Jing Li

McKelvey School of Engineering Theses & Dissertations

As multicore processors become ever more prevalent, it is important for real-time programs to take advantage of intra-task parallelism in order to support computation-intensive applications with tight deadlines. In this thesis, we consider the Global Earliest Deadline First (GEDF) scheduling policy for task sets consisting of parallel tasks. Each task can be represented by a directed acyclic graph (DAG) where nodes represent computational work and edges represent dependences between nodes. In this model, we prove that GEDF provides a capacity augmentation bound of 4-2/m and a resource augmentation bound of 2-1/m. The capacity augmentation bound acts as a linear-time schedulability …

A Study Of Sampling Strategies For Helical Ct, Daheng Li

McKelvey School of Engineering Theses & Dissertations

Two classes of subsampling strategies, partially inspired by ideas from compressed sensing (CS), are developed and tested using real medical x-ray CT data acquired with a helical geometry. A version of the Feldkamp algorithm for helical x-ray CT is described. An alternating minimization (AM) algorithm for finding the maximum-likelihood estimates of attenuation functions in transmission X-ray tomography, developed by O’Sullivan and Benac, is then introduced. The derivation of this AM algorithm is extended to include an optional regularization term, which makes it a MAP estimate. A Newton’s method with trust region modification is implemented for the regularization. In addition, the …

An Approach To Thermocouple Temperature Measurements That Reduces Uncertainties Associated With Radiative Corrections, Siddharth Krishnan

McKelvey School of Engineering Theses & Dissertations

Obtaining accurate temperature measurements in flame environments with thermocouples is extremely challenging due to the effects of radiative heat loss. These losses are difficult to quantify and often cannot be corrected for or minimized without sacrificing spatial resolution. In this work, a new experimental methodology is presented that has shown potential to minimize the temperature correction by both increasing and controlling the effects of convection. This is accomplished through high speed rotation of the thermocouple. The rotation yields a high and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship …

Real-Time Image Processing On An Fpga For An Intraoperative Goggle Device, Yiyi Zhang

McKelvey School of Engineering Theses & Dissertations

The emergence of near-infrared dyes for fluorescence imaging has had a tremendous impact in the medical field. In particular, indocyanin green (ICG) has been widely used for assessing tumor margins during intraoperative procedures. Typically, the dye is intravenously injected into the patient, and after 24 hours the dye is removed from the patient’s body, except where binding between the dye and tumor cells has occurred. This selective binding between ICG and cancerous tissue allows for easy and accurate detection of cancer margins as well as detection of metastasis throughout the patient’s body. In order to detect the binding sites, a …