Digital Commons Network^™

Unified Architecture Of Mobile Ad Hoc Network Security (Mans) System, Li Ling

Dissertations

In this dissertation, a unified architecture of Mobile Ad-hoc Network Security (MANS) system is proposed, under which IDS agent, authentication, recovery policy and other policies can be defined formally and explicitly, and are enforced by a uniform architecture. A new authentication model for high-value transactions in cluster-based MANET is also designed in MANS system. This model is motivated by previous works but try to use their beauties and avoid their shortcomings, by using threshold sharing of the certificate signing key within each cluster to distribute the certificate services, and using certificate chain and certificate repository to achieve better scalability, less …

Automatic Modulation Classification Of Communication Signals, Zaihe Yu

Dissertations

The automatic modulation recognition (AMR) plays an important role in various civilian and military applications. Most of the existing AMR algorithms assume that the input signal is only of analog modulation or is only of digital modulation. In blind environments, however, it is impossible to know in advance if the received communication signal is analogue modulated or digitally modulated. Furthermore, it is noted that the applications of the currently existing AMR algorithms designed for handling both analog and digital communication signals are rather restricted in practice. Motivated by this, an AMR algorithm that is able to discriminate between analog communication …

Fabrication And Characterization Of Back Illuminated Cmos Photodiode Array, Amitra Banerjee

Theses

With the rapid development in low-cost CMOS technology, silicon photodiodes are currently recognized as promising choice for the imager core. In this research, the arrays of back illuminated photodiodes were designed, fabricated and demonstrated with CMOS imager fabrication process on silicon wafers. The main purpose of this work was to improve the contribution of these arrays on the imaging systems before committing their design on the chips.

In this CMOS process, first the n-well, p-well, n+and p+ regions were simulated and fabricated by several implantation processes. The n-well region was implanted by phosphorus at an energy of 170 keV and …

Active Fpga Security Through Decoy Circuits, Bradley D. Christiansen

Theses and Dissertations

Field Programmable Gate Arrays (FPGAs) based on Static Random Access Memory (SRAM) are vulnerable to tampering attacks such as readback and cloning attacks. Such attacks enable the reverse engineering of the design programmed into an FPGA. To counter such attacks, measures that protect the design with low performance penalties should be employed. This research proposes a method which employs the addition of active decoy circuits to protect SRAM FPGAs from reverse engineering. The effects of the protection method on security, execution time, power consumption, and FPGA resource usage are quantified. The method significantly increases the security of the design with …

Advanced Methods In Automatic Modulation Classification For Emerging Technologies, Hong Li

Dissertations

Modulation classification (MC) is of large importance in both military and commercial communication applications. It is a challenging problem, especially in non-cooperative wireless environments, where channel fading and no prior knowledge on the incoming signal are major factors that deteriorate the reception performance. Although the average likelihood ratio test method can provide an optimal solution to the MC problem with unknown parameters, it suffers from high computational complexity and in some cases mathematical intractability. Instead, in this research, an array-based quasi-hybrid likelihood ratio test (qHLRT) algorithm is proposed, which depicts two major advantages. First, it is simple yet accurate enough …

Medium Access Control Design For All-Ip And Ad Hoc Wireless Network, Zaihan Jiang

Dissertations

Medium Access Control (MAC) protocol in a wireless network controls the access of wireless medium by mobile terminals, in order to achieve its fair and efficient sharing. It plays an important role in resource management and QoS support for applications. All-IP wireless WAN is fully IP protocol-based and it is a strong candidate beyond 3G (Third Generation Wireless Network). Ad hoc wireless network has recently been the topic of extensive research due to its ability to work properly without fixed infrastructure.

This dissertation is composed of two main parts. The first part pursues a Prioritized Parallel Transmission MAC (PPTM) design …

Dynamic Bandwidth Management With Service Differentiation Over Ethernet Passive Optical Networks, Yuanqiu Luo

Dissertations

Ethernet passive optical networks (EPONs) address the first mile of the communication infrastructure between the service provider central offices and the customer sites. As a low-cost, high speed technology, EPONs are deemed as the solution to the bottleneck problem of the broadband access network.

A major feature of EPONs is the utility of a shared upstream channel among the end users. Only a single optical network unit (GNU) may transmit during a timeslot to avoid data collisions. In order to provide diverse quality of service (QoS), the bandwidth management of the upstream channel is essential for the successful implementation of …

H-Simd Machine : Configurable Parallel Computing For Data-Intensive Applications, Xizhen Xu

Dissertations

This dissertation presents a hierarchical single-instruction multiple-data (H-SLMD) configurable computing architecture to facilitate the efficient execution of data-intensive applications on field-programmable gate arrays (FPGAs). H-SIMD targets data-intensive applications for FPGA-based system designs. The H-SIMD machine is associated with a hierarchical instruction set architecture (HISA) which is developed for each application. The main objectives of this work are to facilitate ease of program development and high performance through ease of scheduling operations and overlapping communications with computations.

The H-SIMD machine is composed of the host, FPGA and nano-processor layers. They execute host SIMD instructions (HSIs), FPGA SIMD instructions (FSIs) and nano-processor …

Cross-Layer Design For Wireless Sensor Relay Networks, Lichuan Liu

Dissertations

In recent years, the idea of wireless sensor networks has gathered a great deal of attention. A distributed wireless sensor network may have hundreds of small sensor nodes. Each individual sensor contains both processing and communication elements and is designed in some degree to monitor the environmental events specified by the end user of the network. Information about the environment is gathered by sensors and delivered to a remote collector.

This research conducts an investigation with respect to the energy efficiency and the cross-layer design in wireless sensor networks. Motivated by the multipath utilization and transmit diversity capability of space-time …

Performance Analysis Of Collaborative Hybrid-Arq Protocols Over Fading Channels, Igor Stanojev

Theses

Impairments due to multipath signal propagation on the performance of wireless communications systems can be efficiently mitigated with time, frequency or spatial diversity. To exploit spatial diversity, multiple-antenna technology has been thoroughly investigated and emerged as one of the most mature communications areas. However, the need for smaller user terminals, which results in insufficient spacing for antenna collocation, tends to limit the practical implementation of this technology. Without compromising terminal dimensions, future wireless networks will therefore have to exploit their broadcast nature and rely on collaboration between single-antenna terminals for exploiting spatial diversity.

Among cooperative schemes, Collaborative ARQ transmission protocols, …

Investigating The Use Of Intelligent Transportation System Applications To Mitigate The Effects Of Terrorism In Marine Transportation, Kenneth Brown

Theses (Pre-2016)

Contrary to popular belief marine transportation is probably the most vulnerable and the most critical sector of transportation. The Marine Transportation System (MTS) is comprised of ships, tugs, barges, ports, rail and trucking all operating in a highly integrated system. The vulnerability of the MTS to the effects of possible terrorist attacks would not only pose a great threat to the safety of the local community but also our U.S. economy. In other modes of transportation such as surface, air, and mass transit, security and safety issues have been addressed through Technological improvements. Many of these Technological improvements fall under …

Analysis Of Photoconductive Properties In Ge2Sb2Te5 (Gst) Chalcogenide Films For Applications In Novel Electronics, John R. V. Chezem

Theses and Dissertations

This thesis investigated the thermal phase-change properties in Ge₂Sb₂Te₅ (GST) chalcogenide-based films and determined the feasibility of coupling the GST with photosensitive DNA material for novel optical device applications. Modeling and testing of GST were researched with the approach that GST would react as a resistive mechanism through thermal manipulation. A test structure was fabricated with a 2-micronmeter MEMS fabrication process. GST material was deposited (by RF sputtering) on the surface of the test structures. The GST was analyzed primarily in the amorphous to crystalline transition states due to more distinct changes in the resistance …

A Minimum Effort Control Approach To Guided Munition Path Planning, Jeffrey M. Borkowski

Theses and Dissertations

An advance in the development of smart munitions entails autonomously modifying target selection during flight to maximize the value of the target being destroyed. Target identification and classification provides a basis for target value, which is used in conjunction with multi-target tracks to determine an optimal aim point for the munition. A unique guidance law can be constructed that exploits attribute and kinematic data from an onboard video sensor. This thesis develops an innovative path planning algorithm that provides an obstacle avoidance function while navigating the munition toward the highest value target. The foundation of this path planning method is …

A Platform For Antenna Optimization With Numerical Electromagnetics Code Incorporated With Genetic Algorithms, Timothy L. Pitzer

Theses and Dissertations

This thesis investigation presents a unique incorporation of the Method of Moments (MoM) with a Genetic Algorithm (GA). A GA is used in accord with the Numerical Electromagnetics Code, Version 4 (NEC4) to create and optimize typical wire antenna designs, including single elements and arrays. Design parameters for the antenna are defined and encoded into a chromosome composed of a series of numbers. The cost function associated with the specific antenna of interest is what quantifies improvement and, eventually, optimization. This cost function is created and used by the GA to evaluate the performance of a population of antenna designs. …

Comparison Of Ray Tracing Through Ionospheric Models, Shayne C. Aune

Theses and Dissertations

A comparison of ray tracing predictions for transionospheric electromagnetic wave refraction and group delays through ionospheric models is presented. Impacted applications include over-the-horizon RADAR, high frequency communications, direction finding, and satellite communications. The ionospheric models used are version 2.1 of Utah State University's Global Assimilation of Ionospheric Measurements (USU GAIM) model and the 2001 version of the International Reference Ionosphere (IRI) model. In order to provide ray tracing results applicable to satellite communications for satellites at geosynchronous orbit (GEO), a third ionospheric model is used to extend the sub-2000-km USU GAIM and IRI ionospheric specifications to 36540 km in altitude. …

Doppler-Only Multistatic Radar, Dustin G. Mixon

Theses and Dissertations

In order to estimate the position and velocity of a target, most multistatic radar systems require multiple independent target measurements, such as angle-of-arrival, time-of-arrival, and Doppler information. Though inexpensive and reliable, Doppler-only systems have not been widely implemented due to the inherent nonlinear problem of determining a target’s position and velocity from their measurements. We solve this problem. In particular, we first establish the lack of observability in the Doppler-only bistatic system, thereby demonstrating the need for multiple transmitters and/or receivers. Next, for a multistatic system with a sufficient number of transmitter-receiver pairs, we invoke classical optimization techniques, such as …

Design And Characterization Of A Radiation Tolerant Triple Mode Redundant Sense Amplifier Flip-Flop For Space Applications, Mark E. Martin

Theses and Dissertations

One of the more recently proposed flip-flop designs has been the sense amplifier flip-flop. It has gained acceptance in the commercial realm because of its power consumption, speed, setup time, clock line loading, and data line loading characteristics. In this thesis, a recently designed RADHARD version of D sense amplifier flip-flop was taken and a triple mode redundant version for space and radiation environment use was created. The design was created with valuable options to increase radiation hardness and to give end users greater flexibility in realizing their own radiation hardened version of flip-flop. In addition, a methodology for using …

Multi-Dimensional Wave Front Sensing Algorithms For Embedded Tracking And Adaptive Optics Applications, Christopher C. Wood

Theses and Dissertations

Current tracking and adaptive optics techniques cannot compensate for fast-moving extended objects, which is important for ground-based telescopes providing space situational awareness. To fill this need, a vector-projection maximum-likelihood wave-front sensing algorithm development and testing follows for this application. A derivation and simplification of the Cramer-Rao Lower Bound for wavefront sensing using a laser guide star bounds the performance of these systems and guides implementation of a vastly optimized maximum-likelihood search algorithm. A complete analysis of the bias, mean square error, and variance of the algorithm demonstrates exceptional performance of the new sensor. A proof of concept implementation shows feasibility …

An Airborne Radar Model For Non-Uniformly Spaced Antenna Arrays, Matthew V. Young

Theses and Dissertations

This thesis presents an airborne radar model for non-uniformly spaced antenna arrays. Non-uniform arrays potentially possess advantages unobtainable by uniformly spaced arrays. An element position matrix is defined to accommodate arbitrary element locations. The new element position matrix affects the time/phase delay to each element, spatial frequencies, steering vectors, space-time snapshots, and covariance matrices. The joint domain localized and factored time-space-time adaptive processing algorithms are also updated so they are compatible with the new model. The non-uniformly spaced array radar model is verified with previous models presented by Jaffer, Ward, and Hale. The model for non-uniform arrays is used to …

Lqg/Ltr Tilt And Tip Control For The Starfire Optical Range 3.5-Meter Telescope's Adaptive Optics System, Neil D. Paris

Theses and Dissertations

The Air Force Research Laboratory has sponsored research on the tracking control loop portion of the adaptive optics system in the Starfire Optical Range 3.5-meter telescope at Kirtland Air Force Base. The control loop includes two steering mirrors (Coarse Steering Mirror and Fine Steering Mirror) used to remove wavefront tilt and tip phase distortion from light entering the telescope. The objective of this research is to design a single Linear Quadratic Gaussian controller to control both steering mirrors in order to eliminate wavefront tilt and tip distortions induced by the earth's atmosphere, and to evaluate the stability robustness and performance …

Mobile Ad Hoc Networks For Intelligent Systems, Zhigang Wang

Dissertations

Advances in wireless technology and portable computing along with demands for high user mobility have provided a major promotion toward the development of ad hoc networks. Mobile ad hoc networks feature dynamic topology, self-organization, limited bandwidth and battery power of a node. They do not rely on specialized routers for path discovery and traffic routing. Research on ad hoc networks has been extensively investigated in the past few years and related work has focused on many of the layers of the communications architecture.

This research intends to investigate applications of MANET for intelligent systems, including intelligent transportation system (ITS), sensor …

Flow-Oriented Anomaly-Based Detection Of Denial Of Service Attacks With Flow-Control-Assisted Mitigation, Sui Song

Dissertations

Flooding-based distributed denial-of-service (DDoS) attacks present a serious and major threat to the targeted enterprises and hosts. Current protection technologies are still largely inadequate in mitigating such attacks, especially if they are large-scale. In this doctoral dissertation, the Computer Network Management and Control System (CNMCS) is proposed and investigated; it consists of the Flow-based Network Intrusion Detection System (FNIDS), the Flow-based Congestion Control (FCC) System, and the Server Bandwidth Management System (SBMS). These components form a composite defense system intended to protect against DDoS flooding attacks. The system as a whole adopts a flow-oriented and anomaly-based approach to the detection …

Network Level Performance Of Differentiated Services (Diffserv) Networks, Li Zhu

Dissertations

The Differentiated Services (DiffServ) architecture is a promising means of providing Quality of Service (QoS) in Internet. In DiffServ networks, three service classes, or Per-hop Behaviors (PHBs), have been defined: Expedited Forwarding (EF), Assured Forwarding (AF) and Best Effort (BE).

In this dissertation, the performance of DiffServ networks at the network level, such as end-to-end QoS, network stability, and fairness of bandwidth allocation over the entire network have been extensively investigated.

It has been shown in literature that the end-to-end delay of EF traffic can go to infinity even in an over-provisioned network. In this dissertation, a simple scalable aggregate …

A Study Of Steganography And Steganalysis, Nisant Nalla

Theses

Steganography is the art of hiding the fact that communication is taking place, by hiding information in other information. Steganalysis is the study of methods to detect the presence of hidden messages. The Steganography and Steganalysis are very much interdependent. The people in the Steganography domain try to develop stronger methods to hide data in different media. This spurs the discovery of new steganalysis methods which can break these Steganography methods. This is vital for the development of these fields. The internet has been growing by leaps and bounds. There is an increasing need for information security. It has been …

Demarcation Of Coding And Non-Coding Regions Of Dna Using Linear Transforms, Krithika Venkat

Theses

Deoxyribonucleic Acid (DNA) strand carries genetic information in the cell. A strand of DNA consists of nitrogenous molecules called nucleotides. Nucleotides triplets, or the codons, code for amino acids. There are two distinct regions in DNA, the gene and the intergenic DNA, or the junk DNA. Two regions can be distinguished in the gene- the exons, or the regions that code for amino acid, and the introns, or the regions that do not code for amino acid. The main aim of the thesis is to study signal processing techniques that help distinguish between the regions of the exons and the …

Measuring Optical Turbulence Parameters With A Three-Aperture Receiver, David Wayne

Electronic Theses and Dissertations

This thesis discusses methods to measure several atmospheric parameters related to turbulence. Techniques used by two different scintillometers based on weak turbulence theory are discussed along with a method to estimate the inner scale developed by Hill. The theory and minimization algorithm used to infer the atmospheric parameters are discussed. The main focus is on the analysis and collection of experimental data with a three-aperture receiver system. Intensity fluctuations from a CW laser source are collected over a 1km path with three different receiving apertures. The scintillation index is found for each receiving aperture and recently developed theory for all …

Analyis Of Airborne Microwave Polarimetric Radiometer Measurements In The Presence Of Dynamic Platform Attitude Errors, Jean Yves Kabore

Electronic Theses and Dissertations

There are numerous applications for airborne imaging systems in remote sensing, and this thesis deals with a new microwave polarimetric radiometer technique for inferring ocean surface wind direction [3, 5, 7]. This technique is based upon the anisotropy of the polarized ocean blackbody emissions at microwave frequencies relative to the azimuth angle between the microwave radiometer antenna "look" direction and the direction of the wind. Because of the weak wind direction signature, it is important that all systematic brightness temperature (Tb) errors be eliminated, especially those that vary with the radiometer antenna scan position (look direction). This can be accomplished …

Demonstrating Reflectarray Behavior At Infrared, James Ginn

Electronic Theses and Dissertations

Reflectarrays are traditionally passive, planar microstrip antenna devices designed for reflected phase manipulation at each individual antenna element making up the array. By varying the phase response across the surface with the antenna elements, reflectarrays allows a planar surface to exhibit electromagnetically an arbitrary geometry, such as a spherical surface. Initially proposed as a low-cost replacement for bulky parabolic reflectors, reflectarrays have been successfully developed and utilized at both RF and millimeter-wave frequencies. From the standpoint of an optical systems designer, adapting low-frequency reflectarray technology to develop a sub-millimeter and infrared reflectarray (SMIR) would provide a highly desirable alternative to …

High Speed Turbo Tcm Ofdm For Uwb And Powerline System, Yanxia Wang

Electronic Theses and Dissertations

Turbo Trellis-Coded Modulation (TTCM) is an attractive scheme for higher data rate transmission, since it combines the impressive near Shannon limit error correcting ability of turbo codes with the high spectral efficiency property of TCM codes. We build a punctured parity-concatenated trellis codes in which a TCM code is used as the inner code and a simple parity-check code is used as the outer code. It can be constructed by simple repetition, interleavers, and TCM and functions as standard TTCM but with much lower complexity regarding real world implementation. An iterative bit MAP decoding algorithm is associated with the coding …

Design And Characterization Of Noveldevices For New Generation Of Electrostaticdischarge (Esd) Protection Structures, Javier Salcedo

Electronic Theses and Dissertations

The technology evolution and complexity of new circuit applications involve emerging reliability problems and even more sensitivity of integrated circuits (ICs) to electrostatic discharge (ESD)-induced damage. Regardless of the aggressive evolution in downscaling and subsequent improvement in applications' performance, ICs still should comply with minimum standards of ESD robustness in order to be commercially viable. Although the topic of ESD has received attention industry-wide, the design of robust protection structures and circuits remains challenging because ESD failure mechanisms continue to become more acute and design windows less flexible. The sensitivity of smaller devices, along with a limited understanding of the …