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DESIGN, CONSTRUCTION, AND CHARACTERIZATION OF THE YSGR MINIMAL CODON FAB LIBRARY FOR CHAPERONE-ASSISTED RNA CRYSTALLOGRAPHY
Title
DESIGN, CONSTRUCTION, AND CHARACTERIZATION OF THE YSGR MINIMAL CODON FAB LIBRARY FOR CHAPERONE-ASSISTED RNA CRYSTALLOGRAPHY.
Creator
Holmes, Sean, Ye, Jingdong, University of Central Florida
Abstract / Description
Of the entire human genome, 90% of all genetic information is transcribed but only a fraction of that subsequent RNA is translated into proteins. RNAs which are not translated into proteins are deemed non-coding RNAs. Little is known about this large category of noncoding RNAs, although they perform a variety of functions within the cell. RNA crystallography is used to study RNA tertiary structure, which gives insight to the function of these non-coding RNAs. However, complications associated...
Show moreOf the entire human genome, 90% of all genetic information is transcribed but only a fraction of that subsequent RNA is translated into proteins. RNAs which are not translated into proteins are deemed non-coding RNAs. Little is known about this large category of noncoding RNAs, although they perform a variety of functions within the cell. RNA crystallography is used to study RNA tertiary structure, which gives insight to the function of these non-coding RNAs. However, complications associated with RNA crystallography arise due to RNA's lack of surface functional group diversity, flexible tertiary structure, and conformational heterogeneity. A novel technique, Chaperone-assisted RNA crystallography (CARC), can greatly improve the success in crystallization of RNA. With this technique, synthetic antibodies called Antigen Binding Fragments (Fabs) are employed as crystallization chaperones to promote the structure elucidation of certain target RNAs. To identify Fabs that complex with RNA molecules of interest, we constructed a randomized library of synthetic antibodies enriched in ligand binding regions with tyrosine, serine, glycine, and arginine residues. This Fab protein library was constructed with a minimal codon design, and then screened against a variety of RNA targets. Several Fabs have been identified and isolated through phage display selection against three RNA targets. These Fabs were expressed and biochemically characterized for their binding affinities and specificities. To date, five Fabs have been identified and they have outstanding capabilities in binding their specific RNA antigen.
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Date Issued
2012
Identifier
CFH0004167, ucf:44856
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004167
GAUSS-NEWTON BASED LEARNING FOR FULLY RECURRENT NEURAL NETWORKS
Title
GAUSS-NEWTON BASED LEARNING FOR FULLY RECURRENT NEURAL NETWORKS.
Creator
Vartak, Aniket Arun, Georgiopoulos, Michael, University of Central Florida
Abstract / Description
The thesis discusses a novel off-line and on-line learning approach for Fully Recurrent Neural Networks (FRNNs). The most popular algorithm for training FRNNs, the Real Time Recurrent Learning (RTRL) algorithm, employs the gradient descent technique for finding the optimum weight vectors in the recurrent neural network. Within the framework of the research presented, a new off-line and on-line variation of RTRL is presented, that is based on the Gauss-Newton method. The method itself is an...
Show moreThe thesis discusses a novel off-line and on-line learning approach for Fully Recurrent Neural Networks (FRNNs). The most popular algorithm for training FRNNs, the Real Time Recurrent Learning (RTRL) algorithm, employs the gradient descent technique for finding the optimum weight vectors in the recurrent neural network. Within the framework of the research presented, a new off-line and on-line variation of RTRL is presented, that is based on the Gauss-Newton method. The method itself is an approximate Newton's method tailored to the specific optimization problem, (non-linear least squares), which aims to speed up the process of FRNN training. The new approach stands as a robust and effective compromise between the original gradient-based RTRL (low computational complexity, slow convergence) and Newton-based variants of RTRL (high computational complexity, fast convergence). By gathering information over time in order to form Gauss-Newton search vectors, the new learning algorithm, GN-RTRL, is capable of converging faster to a better quality solution than the original algorithm. Experimental results reflect these qualities of GN-RTRL, as well as the fact that GN-RTRL may have in practice lower computational cost in comparison, again, to the original RTRL.
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Date Issued
2004
Identifier
CFE0000091, ucf:46065
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0000091
ON SATURATION NUMBERS OF RAMSEY-MINIMAL GRAPHS
Title
ON SATURATION NUMBERS OF RAMSEY-MINIMAL GRAPHS.
Creator
Davenport, Hunter M, Song, Zi-Xia, University of Central Florida
Abstract / Description
Dating back to the 1930's, Ramsey theory still intrigues many who study combinatorics. Roughly put, it makes the profound assertion that complete disorder is impossible. One view of this problem is in edge-colorings of complete graphs. For forbidden graphs H1,...,Hk and a graph G, we write G "arrows" (H1,...,Hk) if every k-edge-coloring of G contains a monochromatic copy of Hi in color i for some i=1,2,...,k. If c is a (red, blue)-edge-coloring of G, we say c is a bad coloring if G contains...
Show moreDating back to the 1930's, Ramsey theory still intrigues many who study combinatorics. Roughly put, it makes the profound assertion that complete disorder is impossible. One view of this problem is in edge-colorings of complete graphs. For forbidden graphs H1,...,Hk and a graph G, we write G "arrows" (H1,...,Hk) if every k-edge-coloring of G contains a monochromatic copy of Hi in color i for some i=1,2,...,k. If c is a (red, blue)-edge-coloring of G, we say c is a bad coloring if G contains no red K3or blue K1,t under c. A graph G is (H1,...,Hk)-Ramsey-minimal if G arrows (H1,...,Hk) but no proper subgraph of G has this property. Given a family F of graphs, we say that a graph G is F-saturated if no member of F is a subgraph of G, but for any edge xy not in E(G), G + xy contains a member of F as a subgraph. Letting Rmin(K3, K1,t) be the family of (K3,K1,t)-Ramsey minimal graphs, we study the saturation number, denoted sat(n,Rmin(K3,K1,t)), which is the minimum number of edges among all Rmin(K3,K1,t)-saturated graphs on n vertices. We believe the methods and constructions developed in this thesis will be useful in studying the saturation numbers of (K4,K1,t)-saturated graphs.
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Date Issued
2018
Identifier
CFH2000291, ucf:45881
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000291
Taming Wild Faces: Web-Scale, Open-Universe Face Identification in Still and Video Imagery
Title
Taming Wild Faces: Web-Scale, Open-Universe Face Identification in Still and Video Imagery.
Creator
Ortiz, Enrique, Shah, Mubarak, Sukthankar, Rahul, Da Vitoria Lobo, Niels, Wang, Jun, Li, Xin, University of Central Florida
Abstract / Description
With the increasing pervasiveness of digital cameras, the Internet, and social networking, there is a growing need to catalog and analyze large collections of photos and videos. In this dissertation, we explore unconstrained still-image and video-based face recognition in real-world scenarios, e.g. social photo sharing and movie trailers, where people of interest are recognized and all others are ignored. In such a scenario, we must obtain high precision in recognizing the known identities,...
Show moreWith the increasing pervasiveness of digital cameras, the Internet, and social networking, there is a growing need to catalog and analyze large collections of photos and videos. In this dissertation, we explore unconstrained still-image and video-based face recognition in real-world scenarios, e.g. social photo sharing and movie trailers, where people of interest are recognized and all others are ignored. In such a scenario, we must obtain high precision in recognizing the known identities, while accurately rejecting those of no interest.Recent advancements in face recognition research has seen Sparse Representation-based Classification (SRC) advance to the forefront of competing methods. However, its drawbacks, slow speed and sensitivity to variations in pose, illumination, and occlusion, have hindered its wide-spread applicability. The contributions of this dissertation are three-fold: 1. For still-image data, we propose a novel Linearly Approximated Sparse Representation-based Classification (LASRC) algorithm that uses linear regression to perform sample selection for l1-minimization, thus harnessing the speed of least-squares and the robustness of SRC. On our large dataset collected from Facebook, LASRC performs equally to standard SRC with a speedup of 100-250x.2. For video, applying the popular l1-minimization for face recognition on a frame-by-frame basis is prohibitively expensive computationally, so we propose a new algorithm Mean Sequence SRC (MSSRC) that performs video face recognition using a joint optimization leveraging all of the available video data and employing the knowledge that the face track frames belong to the same individual. Employing MSSRC results in a speedup of 5x on average over SRC on a frame-by-frame basis.3. Finally, we make the observation that MSSRC sometimes assigns inconsistent identities to the same individual in a scene that could be corrected based on their visual similarity. Therefore, we construct a probabilistic affinity graph combining appearance and co-occurrence similarities to model the relationship between face tracks in a video. Using this relationship graph, we employ random walk analysis to propagate strong class predictions among similar face tracks, while dampening weak predictions. Our method results in a performance gain of 15.8% in average precision over using MSSRC alone.
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Date Issued
2014
Identifier
CFE0005536, ucf:50313
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005536
Two Ramsey-related Problems
Title
Two Ramsey-related Problems.
Creator
Zhang, Jingmei, Song, Zixia, Zhao, Yue, Martin, Heath, Turgut, Damla, University of Central Florida
Abstract / Description
Extremal combinatorics is one of the central branches of discrete mathematics and has experienced an impressive growth during the last few decades. It deals with the problem of determining or estimating the maximum or minimum possible size of a combinatorial structure which satisfies certain requirements. In this dissertation, we focus on studying the minimum number of edges of certain co-critical graphs. Given an integer r \geq 1 and graphs G, H_1, . . . , H_r, we write G \rightarrow (H_1, ....
Show moreExtremal combinatorics is one of the central branches of discrete mathematics and has experienced an impressive growth during the last few decades. It deals with the problem of determining or estimating the maximum or minimum possible size of a combinatorial structure which satisfies certain requirements. In this dissertation, we focus on studying the minimum number of edges of certain co-critical graphs. Given an integer r \geq 1 and graphs G, H_1, . . . , H_r, we write G \rightarrow (H_1, . . . , H_r) if every r-coloring of the edges of G contains a monochromatic copy of H_i in color i for some i \in {1, . . . , r}. A graph G is (H_1, . . . , H_r)-co-critical if G \nrightarrow (H_1, . . . , H_r), but G+uv \rightarrow (H_1, . . . , H_r) for every pair of non-adjacent vertices u, v in G. Motivated in part by Hanson and Toft's conjecture from 1987, we study the minimum number of edges over all (K_t,\mathcal{T}_k)-co-critical graphs on n vertices, where \mathcal{T}_k denotes the family of all trees on k vertices. We apply graph bootstrap percolation on a not necessarily K_t-saturated graph to prove that for all t \geq 4 and k \geq max{6, t}, there exists a constant c(t,k) such that, for all n \geq (t-1)(k-1)+1, if G is a (K_t,\mathcal{T}_k)-co-critical graph on n vertices, then e(G) \geq ((4t-9)/2+\lceil k/2 \rceil /2)n-c(t,k). We then show that this is asymptotically best possible for all sufficiently large n when t \in {4, 5} and k \geq 6. The method we developed may shed some light on solving Hanson and Toft's conjecture, which is wide open.We also study Ramsey numbers of even cycles and paths under Gallai colorings, where a Gallai coloring is a coloring of the edges of a complete graph without rainbow triangles, and a Gallai k-coloring is a Gallai coloring that uses at most k colors. Given an integer k \geq 1 and graphs H_1, . . . , H_k, the Gallai-Ramsey number GR(H_1, . . . , H_k) is the least integer n such that every Gallai k-coloring of the complete graph K_n contains a monochromatic copy of H_i in color i for some i \in {1, . . . , k}. We completely determine the exact values of GR(H_1, . . . , H_k) for all k \geq 2 when each H_i is a path or an even cycle on at most 13 vertices.
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Date Issued
2019
Identifier
CFE0007745, ucf:52404
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007745
A study of Compressive Sensing for application to Structural Health Monitoring
Title
A study of Compressive Sensing for application to Structural Health Monitoring.
Creator
Ganesan, Vaahini, Das, Tuhin, Kauffman, Jeffrey, Raghavan, Seetha, University of Central Florida
Abstract / Description
One of the key areas that have attracted attention in the construction industry today is Structural Health Monitoring, more commonly known as SHM. It is a concept developed to monitor the quality and longevity of various engineering structures. The incorporation of such a system would help to continuously track health of the structure, indicate the occurrence/presence of any damage in real time and give us an idea of the number of useful years for the same. Being a recently conceived idea,...
Show moreOne of the key areas that have attracted attention in the construction industry today is Structural Health Monitoring, more commonly known as SHM. It is a concept developed to monitor the quality and longevity of various engineering structures. The incorporation of such a system would help to continuously track health of the structure, indicate the occurrence/presence of any damage in real time and give us an idea of the number of useful years for the same. Being a recently conceived idea, the state of the art technique in the field is straight forward - populating a given structure with sensors and extracting information from them. In this regard, instrumenting with too many sensors may be inefficient as this could lead to superfluous data that is expensive to capture and process.This research aims to explore an alternate SHM technique that optimizes the data acquisition process by eliminating the amount of redundant data that is sensed and uses this sufficient data to detect and locate the fault present in the structure. Efficient data acquisition requires a mechanism that senses just the necessary amount of data for detection and location of fault. For this reason Compressive Sensing (CS) is explored as a plausible idea. CS claims that signals can be reconstructed from what was previously believed to be incomplete information by Shannon's theorem, taking only a small amount of random and linear non - adaptive measurements. As responses of many physical systems contain a finite basis, CS exploits this feature and determines the sparse solution instead of the traditional least - squares type solution. As a first step, CS is demonstrated by successfully recovering the frequency components of a simple sinusoid. Next, the question of how CS compares with the conventional Fourier transform is analyzed. For this, recovery of temporal frequencies and signal reconstruction is performed using the same number of samples for both the approaches and the errors are compared. On the other hand, the FT error is gradually minimized to match that of CS by increasing the number of regularly placed samples. Once the advantages are established, feasibility of using CS to detect damage in a single degree of freedom system is tested under unforced and forced conditions. In the former scenario, damage is indicated when there is a change in natural frequency of vibration of the system after an impact. In the latter, the system is excited harmonically and damage is detected by a change in amplitude of the system's vibration. As systems in real world applications are predominantly multi-DOF, CS is tested on a 2-DOF system excited with a harmonic forcing. Here again, damage detection is achieved by observing the change in the amplitude of vibration of the system. In order to employ CS for detecting either a change in frequency or amplitude of vibration of a structure subjected to realistic forcing conditions, it would be prudent to explore the reconstruction of a signal which contains multiple frequencies. This is accomplished using CS on a chirp signal.Damage detection is clearly a spatio-temporal problem. Hence it is important to additionally explore the extension of CS to spatial reconstruction. For this reason, mode shape reconstruction of a beam with standard boundary conditions is performed and validated with standard/analytical results from literature. As the final step, the operation deflection shapes (ODS) are reconstructed for a simply supported beam using CS to establish that it is indeed a plausible approach for a less expensive SHM. While experimenting with the idea of spatio-temporal domain, the mode shape as well as the ODS of the given beam are examined under two conditions - undamaged and damaged. Damage in the beam is simulated as a decrease in the stiffness coefficient over a certain number of elements. Although the range of modes to be examined heavily depends on the structure in question, literature suggests that for most practical applications, lower modes are more dominant in indicating damage. For ODS on the other hand, damage is indicated by observing the shift in the recovered spatial frequencies and it is confirmed by the reconstructed response.
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Date Issued
2014
Identifier
CFE0005334, ucf:50520
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005334
A Crack in Everything
Title
A Crack in Everything.
Creator
Hoffman, Jeffrey, Isenhour, David, Poindexter, Carla, Kim, Joo, University of Central Florida
Abstract / Description
Contained herein is a close examination of self-awareness and self-portraiture as it applies to the works of artist Jeffrey Hoffman. Water, frozen into various forms and combined with natural elements of wood, slowly melt over an indeterminable amount of time, each droplet documented as the process transforms the elements. Through this process, we see change. We see time. We see truth. This documentation of change and time through natural elements is where the artwork comes full circle....
Show moreContained herein is a close examination of self-awareness and self-portraiture as it applies to the works of artist Jeffrey Hoffman. Water, frozen into various forms and combined with natural elements of wood, slowly melt over an indeterminable amount of time, each droplet documented as the process transforms the elements. Through this process, we see change. We see time. We see truth. This documentation of change and time through natural elements is where the artwork comes full circle. Working with new media to explore man's interconnectivity to life, energy, and the cosmos, he produces time based installations, photographs, videos, and sculptures that serve as both existential metaphors and Tantric symbols. With the use of digital cameras and video, a record is created by which the disintegration which occurs from the unseen forces of gravity, heat and time upon sculptures made from natural elements and ice is examined. In its sculptural form, his work can be categorized as Installation art and Performance art due to its evolving nature. Each piece is intended to either change over time or to have that change halted by another temporal force like that of flowing electricity. The possibility of allowing varying levels of self-awareness to emerge through self portraiture is also examined. The existential, as well as the metaphysical, can be present in a physical form when the form is imbued with evidence of an evolutionary process. In many ways, the work serves as a self portrait. It is a means for Hoffman to examine his own existentialism as a student of the modern western world and life.
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Date Issued
2012
Identifier
CFE0004242, ucf:49518
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004242
Structural and Functional Studies of Glycine Riboswitches and Development of Fab Chaperone Assisted RNA Crystallography
Title
Structural and Functional Studies of Glycine Riboswitches and Development of Fab Chaperone Assisted RNA Crystallography.
Creator
Sherman, Eileen, Ye, Jingdong, Kolpashchikov, Dmitry, Koculi, Eda, Harper, James, Self, William, University of Central Florida
Abstract / Description
The glycine riboswitch is a structured RNA found upstream of genes in mRNA transcripts in many bacteria, functioning as a biofeedback gene regulator. Upon binding glycine, a complete RNA transcript including gene sequences is transcribed, effectively turning on gene expression. In an effort to understand the intricacies of its functioning, many mutants of the riboswitch were made and characterized during Ph. D. work, resulting in discovery of a P0 duplex/kink-turn motif involving a few...
Show moreThe glycine riboswitch is a structured RNA found upstream of genes in mRNA transcripts in many bacteria, functioning as a biofeedback gene regulator. Upon binding glycine, a complete RNA transcript including gene sequences is transcribed, effectively turning on gene expression. In an effort to understand the intricacies of its functioning, many mutants of the riboswitch were made and characterized during Ph. D. work, resulting in discovery of a P0 duplex/kink-turn motif involving a few nucleotides upstream of the established glycine riboswitch sequence which changed its ligand binding characteristics (Chapter 1). Previously, the two aptamers of the riboswitch were thought to cooperatively bind glycine, but with the inclusion of this leader sequence which forms a kink turn motif with the linker between the two aptamers, glycine binding in one aptamer no longer requires glycine binding in the other. Furthermore, the Kd from three species tested are now a similar, lower value of about 5 (&)#181;M, indicating authenticity of this new consensus sequence. Glycine binding and interaptamer interaction both enhanced one another in trans aptamer assays. Another discovery from this was a shortened construct including all of aptamer II but only part of aptamer I in which a few specific nucleotides prevented glycine binding in aptamer II (Chapter 2). This may provide insight into the nature of interaptamer interactions in the full switch; addition of an oligonucleotide complimentary to these nucleotides restored glycine binding ability to aptamer II. With future development, this could also be a useful molecular biology tool, using two signals, glycine and an oligonucleotide, to allow gene expression.To precisely understand how any macromolecule functions, a 3D structure, obtainable by x-ray crystallography, is vital. A new technique to accomplish that for RNA, precedented in the protein world, is Fab chaperoned crystallography, which has advantages compared to RNA alone. A phage displayed library of Fabs with reduced codon diversity designed for RNA was created, the YSGR Min library (Chapter 3). Its Fabs had specificities and affinities equal to or greater than previous libraries which were originally created for phage displayed selection against proteins. Fab chaperoned RNA crystallography is currently in progress for the glycine riboswitch; the best resolution thus far is 5.3 (&)#197; (Chapter 4). In addition to providing molecular insight into its gene regulation mechanism, a structure of the glycine riboswitch could be applied for use in structure based drug design of novel antibiotics targeting the riboswitch to disrupt important downstream carbon cycle genes in pathogenic bacteria.
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Date Issued
2014
Identifier
CFE0005549, ucf:50285
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005549
OPTIMAL DETOUR PLANNING AROUND BLOCKED CONSTRUCTION ZONES
Title
OPTIMAL DETOUR PLANNING AROUND BLOCKED CONSTRUCTION ZONES.
Creator
Jardaneh , Mutasem, Khalafallah, Ahmed, University of Central Florida
Abstract / Description
Construction zones are traffic way areas where construction, maintenance or utility work is identified by warning signs, signals and indicators, including those on transport devices that mark the beginning and end of construction zones. Construction zones are among the most dangerous work areas, with workers facing workplace safety challenges that often lead to catastrophic injuries or fatalities. In addition, daily commuters are also impacted by construction zone detours that affect their...
Show moreConstruction zones are traffic way areas where construction, maintenance or utility work is identified by warning signs, signals and indicators, including those on transport devices that mark the beginning and end of construction zones. Construction zones are among the most dangerous work areas, with workers facing workplace safety challenges that often lead to catastrophic injuries or fatalities. In addition, daily commuters are also impacted by construction zone detours that affect their safety and daily commute time. These problems represent major challenges to construction planners as they are required to plan vehicle routes around construction zones in such a way that maximizes the safety of construction workers and reduces the impact on daily commuters. This research aims at developing a framework for optimizing the planning of construction detours. The main objectives of the research are to first identify all the decision variables that affect the planning of construction detours and secondly, implement a model based on shortest path formulation to identify the optimal alternatives for construction detours. The ultimate goal of this research is to offer construction planners with the essential guidelines to improve construction safety and reduce construction zone hazards as well as a robust tool for selecting and optimizing construction zone detours.
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Date Issued
2011
Identifier
CFE0003586, ucf:48900
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003586
On Distributed Estimation for Resource Constrained Wireless Sensor Networks
Title
On Distributed Estimation for Resource Constrained Wireless Sensor Networks.
Creator
Sani, Alireza, Vosoughi, Azadeh, Rahnavard, Nazanin, Wei, Lei, Atia, George, Chatterjee, Mainak, University of Central Florida
Abstract / Description
We study Distributed Estimation (DES) problem, where several agents observe a noisy version of an underlying unknown physical phenomena (which is not directly observable), and transmit a compressed version of their observations to a Fusion Center (FC), where collective data is fused to reconstruct the unknown. One of the most important applications of Wireless Sensor Networks (WSNs) is performing DES in a field to estimate an unknown signal source. In a WSN battery powered geographically...
Show moreWe study Distributed Estimation (DES) problem, where several agents observe a noisy version of an underlying unknown physical phenomena (which is not directly observable), and transmit a compressed version of their observations to a Fusion Center (FC), where collective data is fused to reconstruct the unknown. One of the most important applications of Wireless Sensor Networks (WSNs) is performing DES in a field to estimate an unknown signal source. In a WSN battery powered geographically distributed tiny sensors are tasked with collecting data from the field. Each sensor locally processes its noisy observation (local processing can include compression,dimension reduction, quantization, etc) and transmits the processed observation over communication channels to the FC, where the received data is used to form a global estimate of the unknown source such that the Mean Square Error (MSE) of the DES is minimized. The accuracy of DES depends on many factors such as intensity of observation noises in sensors, quantization errors in sensors, available power and bandwidth of the network, quality of communication channels between sensors and the FC, and the choice of fusion rule in the FC. Taking into account all of these contributing factors and implementing a DES system which minimizes the MSE and satisfies all constraints is a challenging task. In order to probe into different aspects of this challenging task we identify and formulate the following three problems and address them accordingly:1- Consider an inhomogeneous WSN where the sensors' observations is modeled linear with additive Gaussian noise. The communication channels between sensors and FC are orthogonal power and bandwidth-constrained erroneous wireless fading channels. The unknown to be estimated is a Gaussian vector. Sensors employ uniform multi-bit quantizers and BPSK modulation. Given this setup, we ask: what is the best fusion rule in the FC? what is the best transmit power and quantization rate (measured in bits per sensor) allocation schemes that minimize the MSE? In order to answer these questions, we derive some upper bounds on global MSE and through minimizing those bounds, we propose various resource allocation schemes for the problem, through which we investigate the effect of contributing factors on the MSE.2- Consider an inhomogeneous WSN with an FC which is tasked with estimating a scalar Gaussian unknown. The sensors are equipped with uniform multi-bit quantizers and the communication channels are modeled as Binary Symmetric Channels (BSC). In contrast to former problem the sensors experience independent multiplicative noises (in addition to additive noise). The natural question in this scenario is: how does multiplicative noise affect the DES system performance? how does it affect the resource allocation for sensors, with respect to the case where there is no multiplicative noise? We propose a linear fusion rule in the FC and derive the associated MSE in closed-form. We propose several rate allocation schemes with different levels of complexity which minimize the MSE. Implementing the proposed schemes lets us study the effect of multiplicative noise on DES system performance and its dynamics. We also derive Bayesian Cramer-Rao Lower Bound (BCRLB) and compare the MSE performance of our porposed methods against the bound.As a dual problem we also answer the question: what is the minimum required bandwidth of thenetwork to satisfy a predetermined target MSE?3- Assuming the framework of Bayesian DES of a Gaussian unknown with additive and multiplicative Gaussian noises involved, we answer the following question: Can multiplicative noise improve the DES performance in any case/scenario? the answer is yes, and we call the phenomena as 'enhancement mode' of multiplicative noise. Through deriving different lower bounds, such as BCRLB,Weiss-Weinstein Bound (WWB), Hybrid CRLB (HCRLB), Nayak Bound (NB), Yatarcos Bound (YB) on MSE, we identify and characterize the scenarios that the enhancement happens. We investigate two situations where variance of multiplicative noise is known and unknown. Wealso compare the performance of well-known estimators with the derived bounds, to ensure practicability of the mentioned enhancement modes.
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Date Issued
2017
Identifier
CFE0006913, ucf:51698
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006913