NC State Theses and Dissertations
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- A 1 Mbps Underwater Communication System Using a 405 nm Laser Diode and Photomultiplier Tube(2008-12-07) Cox, William Charles, Jr.; Dr. Brian Hughes, Committee Member; Dr. John Muth, Committee Chair; Dr. Robert Kolbas, Committee MemberRadio frequency communications in seawater are impractical due to high conductivity of seawater limiting the propagation of electromagnetic waves. Current methods, such as acoustic communication, are limited in bandwidth, and the use of cables, such as fiber optic, are expensive and not practical for autonomous vehicles. Underwater tethered communication systems are also very costly to repair if damaged. Optical wireless communications that exploit the blue/green transparency window of seawater potentially offer high bandwidth, although short range, communications. The goal of this Masters thesis was to build sufficient infrastructure to experimentally validate the performance of underwater optical communication systems under laboratory, but hopefully realistic, water conditions. An optical transmitter based on a 405nm blue laser diode was constructed. The transmitter is capable of sourcing 200mA of current to a blue laser diode at speeds of up to 200MHz. The receiver was based on a photomultiplier tube. The high gain and blue/green sensitivity of a photomultiplier tube make it ideal for underwater optical communications. Finally, a 1,200 gallon water tank was constructed that allows the water conditions to be appropriately controlled to simulate an ocean environment Experiments were conducted to validate the design and construction of the receiver, transmitter and water tank. An underwater optical data link was demonstrated that was capable of transmitting data at 500kpbs in return-to-zero format, or 1Mpbs in non-return-tozero format. The transmitted signal could then be optically detected, digitized and stored on a PC for later signal processing.
- A 1 Mbps Underwater Communications System using LEDs and Photodiodes with Signal Processing Capability(2008-12-07) Simpson, Jim Anto; Dr. Brian Hughes, Committee Member; Dr. Leda Lunardi, Committee Member; Dr. John F. Muth, Committee ChairThe inability of radio frequency electromagnetic waves to propagate without attenuation in seawater has traditionally limited underwater communications to acoustics or tethered systems. High bandwidth optical communication systems have been demonstrated for terrestrial and space applications. There is growing interest to see if short range high bandwidth optical wireless systems can be made for the underwater environment. In this thesis we demonstrate a 1 Mbps optical wireless system using LEDs and PIN photodiodes that also incorporates capabilities for signal processing of the received data to be performed. Lasers and Photomultiplier tubes offer high performance, and are generally used in most underwater optical communication systems. However, these components are relatively expensive and can have large form factors. As an alternative solution the much cheaper and more compact LEDs and photodiodes are used as transmitters and receiver components. However, compared to a laser and PMT based system, such a system would be strongly disadvantaged in photon limited environments. If one assumes that photons actually reach the receiver, using signal processing techniques, optimized modulation formats, and error-correction coding, one expects that the range of the system can be extended. The development of a prototype system for the experimentation and verification of this proposition is the main motivation of this thesis. Small, compact transmitters using High Power LEDs and receivers using Si Photodiodes where the data can be digitally sampled such that signal processing techniques can be applied were constructed and demonstrated using a 12 foot, 1200 gallon tank that was also constructed for the project. It was shown that the LED and photodiode based system works well for short ranges, and that advantages can be obtained using digital signal processing. The applicability of this strategy to use digital signal processing techniques can be easily extended to higher performance Laser/PMT based systems.
- 1.9A Crystal Structure of the Rap1a GTPase Bound to its Natural Ligand, GTP(2007-01-21) Miller, Christopher Michael; Carla Mattos, Committee Chair; Clay Clark, Committee Member; Robert Rose, Committee MemberRap1a is a small GTPase in the Ras superfamily whose most well known function is to antagonize the Ras. Rap1a and Ras share common effectors which allow Rap1a to either unproductively bind Ras' effectors forming an inactive complex or sequester Ras' effectors away from the plasma membrane where Ras is inserted by C-terminal post-translational modifications. To date, a 2.2Å crystal structure of Rap1a bound to the non-hydrolyzable GTP analogue, GMPPNP, and one of its effectors, Raf-1, has been solved. This thesis presents the 1.9Å monomeric form of Rap1a bound to its natural ligand, GTP. Comparisons made between the previously published Rap—Raf structure, Rap2a, H-Ras, and RalA shed some light on the functions for conserved areas of Rap1a. The presence of a unique salt bridge at the Rap⁄Raf interface, a new conformation of threonine 61, a possible link for switch the II residue phenylalanine 64 with GAP-induced GTPase activity, and a suggested role for α helix 4 contribute to the Rap1a story.
- The 1/k-Eulerian Polynomials.(2012-03-26) Viswanathan, Gopal; Carla Savage, Chair; Jon Doyle, Member; Steffen Heber, Member
- A 100 Motor Study: Investigating pre-EPAct Motors as a Subset of the Industrial Motor Population with Regards to the Economics of Motor Repair and Replace Decisions(2005-04-05) Kaufman, Nicole Marie; Alexander O. Hobbs, Committee Member; James W. Leach, Committee Member; Richard R. Johnson, Committee ChairIn the absence of hard data, the engineering world tends to be overly conservative in estimating benefits of change. The hypothesis herein discussed is that with hard data, the economics of motor repair/replace decisions could change significantly. If true, this could appreciably boost the efficiency of the industrial motor population by affecting the penetration of high-efficiency motors, such as NEMA Premiums. The energy savings from motor replacement depend on the difference between the efficiency of the new motor and the old motor. There has been a great deal of work investigating new motor efficiency and very little work investigating the actual running efficiency of older motors in the field. Motors that have operated for years experiencing failures and repairs may operate below their original nameplate or assumed efficiency. This study is a preliminary investigation of the efficiency of motors in industrial settings with the purpose of updating currently available motor analysis software tools to reflect more accurately the economic benefits of utilizing high-efficiency industrial induction motors.
- 17b-Estradiol is Abundant in Skin and Regulates the Hair Follicle Cycle and Mirex Tumor Promotion(2002-01-07) Porter, Karen; Robert C. Smart, Chair; C. Lee Robinette, Co-chair; Ronald Baynes, member; Gerald A. LeBlanc, memberSkin is a complex, hormone responsive tissue that functions as a barrier against water loss and infection. Estrogens have been shown to influence dermal thickness, vasodilatation and hair growth in skin. Remarkably, cutaneous E2 levels and capacity for E2 synthesis have not been fully assessed. We have determined that cutaneous17b-estradiol (E2) levels average nine times greater than serum E2 levels in female mice and that skin E2 is independent of serum E2. Additionally, we determined that estrogens are a major metabolite of testosterone in mouse skin explants, indicating that skin is a major site of extraglandular estrogen biosynthesis. Earlier studies have shown that castration accelerates hair growth in mice, and we have determined that castration induces a greatly diminished telogen phase, of the hair cycle. Previously our laboratory has shown that E2 blocks telogen to anagen transition of the hair cycle. We observed that only twice weekly 1 nmol E2 treatment reversed the effects of castration while daily treatment with 100 nmol testosterone or 25 nmol DHT was required, indicating that E2 is up to 100 times more potent than androgens. Previous studies have shown that mirex, a non-phorbol ester skin tumor promoter, promotes three times more tumors in female mice than OVX mice. E2 implants were able to restore 80% of the intact female mirex promotion response to OVX mice, indicating that E2 is the primary ovarian hormone that regulates mirex promotion. Since mirex promotes three times more tumors in female mice than in male mice, we conducted a tumor promotion study on intact and castrate mice given empty or E2 containing implants, and found that intact mice develop three times more tumors than castrated mice and that E2 implants fully restore intact male response to castrate mice, indicating that E2 also regulates mirex tumor promotion sensitivity in male mice. Collectively, these data indicate that skin is an important extraglandular source of E2 and skin E2 influences the hair cycle and chemical carcinogenesis.
- 19Ne Excited States and Resonances in the 18F(p,α)15O Reaction in Classical Novae.(2022-02-16) Portillo Chaves, Federico Exeario; Richard Longland, Chair; Albert Young, Member; James Kneller, Member; Robert Janssens, Inter-Institutional; Ethan Hyland, Graduate School Representative
- 2013 Climate Change Attitudes of Southeast Forestry Professionals: Implications for Outreach.(2014-01-27) Morris, Hilary Lynn Cole; Mark Megalos, Chair; Rua Mordecai, Member; Markus Peterson, Member
- 2016 Archaeological Survey of the Lake Phelps Northern Shoreline.(2017-03-20) Jordan, Robert Andrew; John Millhauser, Chair; Daniel Case, Member; Nora Haenn, Member; John Mintz, External
- 20th Century Texts-19th Century Narratives: Literary Convention in Paul Muldoon's Madoc: A Mystery and Ishmael Reed's Flight to Canada.(2007-04-06) Mullins, Matthew; Mary Helen Thuente, Committee Member; Tom Lisk, Committee Chair; Michael Grimwood, Committee MemberThis thesis explores how Paul Muldoon and Ishmael Reed use literary and historical conventions to comment on the value of literary conventions in the context of contemporary literature and culture. Muldoon uses poetic conventions in Madoc: A Mystery, while Reed uses slave narrative conventions in Flight to Canada. The value of reexamining these conventions in a contemporary context is to see their persisting importance and influence in literature and culture, and also to see where, perhaps, they may have fallen short as is the case with some of the slave narrative conventions appropriated by Reed. No previous research has placed Madoc and Flight to Canada side by side. By placing these two texts side by side, we can get a better idea of the irreducible complexity of language. Both Muldoon and Reed use language that can only be reduced to a lowest common denominator that is, in itself, complex. Both authors also offer a revisionist history that questions capital "T" truth, and the concepts of time and history in general. And, in both texts, America is critiqued for falling short of its once-ripe New World aspirations. By appropriating literary conventions, Muldoon and Reed pull two hundred years into the span of a few hundred pages, and use convention to challenge convention while learning from convention in the process.
- 2D Human Pose Estimation by Integrating Convolutional Neural Networks and Structural Information.(2019-11-06) Dong, Liang; Tianfu Wu, Co-Chair; Min Chi, Co-Chair; Edgar Lobaton, Member; Christopher Healey, Member
- 3-D Computed Tomography Using Diffraction Enhanced Imaging Modality(2003-04-17) Horiba, Hironobu; Sarah A. Rajala, Committee Member; Dale E. Sayers, Committee Co-Chair; Kuruvilla Verghese, Committee Co-ChairAtomic and nuclear radiation has been used to develop a large variety of medical imaging modalities for the benefit of humankind over the past fifty years. Diffraction Enhanced Imaging (DEI) is a new x-ray radiographic imaging modality using monochromatic x-rays to produce very clear digital radiographs of objects by virtually eliminating the detection of scattered photons and exploiting the refraction properties of the object. Being free of scatter DEI images have shown dramatically improved contrast over standard radiographs of the same object. The main objective of this work was to apply DEI to computed tomography (CT) and obtain three-dimensional tomographic images. Two sets of experiments on Lucite phantoms were performed at the X15A beamline of National Synchrotron Light Source. The first experiment was performed to evaluate previous work related to this work. The second experiment was performed to obtain threedimensional CT data. Three-dimensional images were successfully obtained and the apparent absorption and refraction images obtained from DEI showed information unavailable in conventional radiograph in computed tomography. There are two interesting findings in this research. One is that subtraction method for calculating refraction images which we suggested is found to be relatively free from contamination from the absorption component. The other is that the procedural orders of manipulation of taking logarithm and subtraction/addition seriously affect the quality of image. If one mixes this order, the result shows a hump-like artifact in both the absorption and refraction images. For further improvements, an experimental method for preventing drifting of the rocking curve during the data acquisition and for fully separating the absorption and refraction components of the DEI data need further study. Also, it is recommended that an algorithm for automatically correcting for the off-axis rotation should be developed.
- 3-D Microstructure Creation Using Elliptical Vibration-Assisted Machining (EVAM).(2014-06-26) Brehl, David Edward; Thomas Dow, Chair; Ronald Scattergood, Member; Paul Ro, Member; Gregory Buckner, Member
- 3-D Prismatic Packaging Methodologies for Wide Band Gap Power electronics Modules(2017-09-15) Ke, Haotao; Douglas Hopkins, Chair; Subhashish Bhattacharya, Member; B. Baliga, Member; Ola Lars Harrysson, Member
- 3-tier Service Level Agreement with Automatic Class Upgrades(2006-04-12) Haddad, Reda Nassif; Yannis Viniotis, Committee ChairTremendous efforts have been spent on devising mechanisms that would provide Quality of Service (QoS) needed by various applications, and network operators have spent a lot of resources trying to fit their networks with differentiated services capabilities. One of the Service Level Agreements (SLA) promising to sell these QoS services is the "triple play" SLA, bundling 3 classes of services targeting voice, data and video. In particular, circuit switched network operators envision the triple play SLA as essential to revenue maintenance, customer retention, and growth. It is their way, through the IP Multimedia Subsystem (IMS) standardization for example, to move all non-IP current and future services, such as voice, onto IP. In this thesis, we propose a "3-tier SLA with automatic class upgrades", an enhancement to the triple play SLA, in that it automatically upgrades lower classes' packets to fill gaps or unused bandwidth in the upper classes. The proposed SLA incorporates a scalable solution to the reordering problem, caused by upgrading lower class-packets to upper classes; the solution does not require per flow state information. We provide a thorough analysis of the QoS performance in terms of goodput, losses and delay of both UDP and TCP sources and show that the proposed SLA maximizes the customer's utilization of the reserved and paid-for bandwidth by maximizing the utilization of the most expensive, better service, upper QoS classes, and provides much greater throughput than the proposed "triple play" model.
- 3D Apparel Visualization Technology Customization for Pants Based on Three Body Types.(2020-03-25) Hartis, Peyton Leanne; Cynthia Istook, Chair; Jane Porterfield, Member; Traci Lamar, Member
- 3D face recognition from range images(2010-05-03) Miao, Shun; Griff Bilbro, Committee Member; Wesley Snyder, Committee Member; Hamid Krim, Committee ChairIn this thesis, we explore the statistical and geometrical behavior of uncontrolled parameters of human face, including both rigid transform caused by head pose and non-rigid transform caused by facial expression. We focus on developing 3D facial recognition schemes that can be robust for these uncontrolled parameters. This thesis presents a novel 3D face recognition method by means of the evolution of iso-geodesic distance curves. Specifically, the proposed method compares two neighboring iso-geodesic distance curves, and formalizes the evolution between them as a one-dimensional function, named evolution angle function, which is Euclidean invariant. The novelty of this paper consists in formalizing 3D face by an evolution angle functions, and in computing the distance between two faces by that of two functions. Experiments on Face Recognition Grand Challenge (FRGC) ver2.0 shows that our approach works very well on neutral faces. By introducing a weight function, we also show a promising result on non-neutral face database. A 3D surface segmentation scheme is developed to detect the partial similarity between facial images. The proposed algorithm is based on iterative closest point (ICP) algorithm, which uses mean square distance as the cost function and is not able to detect partial similarities. The presented thesis make an improvement of ICP algorithm by iteratively removing points contributing largest error, and the remaining area of surface can be shown to be the partial similarity between two surface
- 3D Integral Invariant Signatures And Their Application on Face Recognition(2007-09-17) Feng, Shuo; Hamid Krim, Committee Chair; Irina Kogan, Committee Member; Michael Escuti, Committee Member; Griff Bilbro, Committee MemberCurves are important features in computer vision and pattern recognition, and their classification under a variety of transformations, such as Euclidean, affine or projective, poses a great challenge. Invariant features of these curves turn out to be crucial to simplifying any classification procedure. This, as a result, has recently led to a renewed research interest in transformation invariants. In this thesis, new explicit formulae for integral invariants for curves in 3D with respect to the special and the full affine groups are presented.The development of the 3D integral invariant are based on an inductive approach in terms of Euclidean invariants. For the first time, a clear geometric interpretation of both 2D and 3D integral invariants is presented. Since integration attenuates the effects of noise, integral invariants have advantages in computer vision applications. We use integral invariants to construct global and local signatures that characterize curves up to the special affine transformations, subsequently extended to the full affine group. Global Signatures are independent of parameterization, and Local Signatures are independent of both parameterizationa and initial point selection. We analyze the robustness of these invariants in their application to the problem of classification of noisy spatial curves extracted as characteristics from a 3D object. Our investigation of 2D and 3D integral invariants and signatures, originally motivated by Biometrics applications, are successfully implemented and applied to face recognition to eliminate the effects of pose and facial expression. A high recognition performance rate of 95% is achieved in the test with a large face data set.
- 3D Nanofabrication Using AFM-Based Ultrasonic Vibration Assisted Nanomachining.(2017-07-18) Deng, Jia; Jingyan Dong, Co-Chair; Paul Cohen, Co-Chair; Chih-Hao Chang, Minor; Yuan-Shin Lee, Member; Consuelo Arellano, Graduate School Representative
- 3D Orthogonal Woven Glass Fiber Reinforced Polymeric Bridge Deck: Fabrication and Experimental Investigation(2004-10-27) Norton, Taylor Montgomery; Sami Rizkalla, Committee Chair; Amir Mirmiran, Committee Co-Chair; Jack Lesko, Committee Member; Emmett Sumner, Committee MemberRapid deterioration of civil infrastructure has created one of the major challenges facing the construction industry. In recent years, fiber reinforced polymers (FRP) have emerged as a potential solution to the tribulations associated with deficient bridge decks. The main objective of the proposed research is to adapt the 3-D orthogonal 3Weaving™ process to develop an innovative completely woven fiber reinforced polymeric bridge deck. The research accomplished fabricating a unique 3Weaving™ loom capable of weaving an E-glass preform which 'puffs out' into an open cell truss-like structure aimed to overcome each the weaknesses of its predecessors. The project succeeded in providing fiber reinforcement through the connection of the truss core components with the outer composite deck skins. The loom provided continuous fiber reinforcement through these top and bottom skins. And the innovative fiber architecture provided inplane fiber reinforcement in each of the structural components. Two 5' long by 15' wide deck preforms were produced: the first 1 ½ thick and the second 3' thick. In addition, a 2' long by 12' wide by 1 ½ thick non-truss composite deck was produced for comparison. The truss oriented decks utilized triangular cut shafts of Balsa as core inserts, and the non-truss deck maintained a rectangular block of Balsa core; each deck was infused with an epoxy resin; and concrete was cast atop. Each of the decks was tested for stiffness and strength in three-point bend. The stiffness tests comprised loading and unloading the deck in 2 kip increments up to 22 kips and using linear regression analysis to ascertain any degradation in stiffness. The strength tests consisted of loading the deck until failure. The testing exemplified the importance of the attachment of the core structural components to the outer composite deck skins and demonstrated a resistance of delamination of the core to the outer skins and the outer skins to themselves.