Digital Commons Network^™

Bulk Power System Low Frequency Oscillation Suppression By Facts/Ess, Li Zhang, Y. Liu, Michael R. Ingram, Dale T. Bradshaw, Steve Eckroad, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Low frequency oscillations in the interconnected power systems are observed all around the world. In this paper, the authors studied the inter-area mode low frequency oscillations by analyzing the phenomena in Nashville area of the Tennessee Valley Authority (TVA) system. Our study revealed 4 dynamic groups of generators in this area. Within each group, generators swing together and have the same dynamic trend. Generators from different dynamic groups swing against each other. The authors studied the possibility of using a FACTS/ESS controller to damp the low frequency oscillations in Nashville area. The active power is controlled to damp the low …

Optical Filter Elements And Methods Of Making And Using Same, Michael A. Scobey, Lucien P. Ghislain, Dennis J. Derickson, Loren F. Stokes

Electrical Engineering

Optical filter elements and optical systems comprise optically mismatched etalons and optically mismatched stacked, optically coupled etalons that are directly optically coupled, at least one of the etalons or stacked, optically coupled etalons comprising first and second selectively transparent thin film mirror coatings on opposite surfaces of a bulk optic. The optically mismatched etalons can be configured to selectively pass single passbands. The disclosed optical systems optionally comprise other devices optically coupled to the optically mismatched etalons and optionally mismatched stacked, optically coupled etalons.

Integrated Vlsi Potentiostat For Cyclic Voltammetry In Electrolytic Reactions, Harpreet S. Narula, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes a CMOS integrated potentiostatic control circuit. The design maintains a constant bias potential between the reference and working electrodes for an amperometric chemical sensor. A technique of converting input currents into time for amperometric measurements is proposed. Redox currents ranging from IpA to 200nA can be measured with a maximum non-linearity of ±0.1% over this range. The design can be used to generate a cyclic voltammogram for an electrochemical reaction by sweeping the voltages across the range specified by the user. Analog inputs are processed, and digital outputs are generated without requiring a power-hungry A/D converter. A …

Establishing A Cyber Warrior Force, Scott D. Tobin

Theses and Dissertations

Cyber Warfare is widely touted to be the next generation of warfare. As America's reliance on automated systems and information technology increases, so too does the potential vulnerability to cyber attack. Nation and non-nation states are developing the capability to wage cyber warfare. Historically, the Air Force and DoD have concentrated their efforts toward defensive network operations. However, a shift in doctrine has shown both the Air Force and DoD acknowledging the potential for Information Warfare. What appears to be lacking is the trained and educated cyber warrior force that will carry out the information operations if needed. This research …

Volume Holographic Recording And Readout For 90-Deg Geometry, Partha P. Banerjee, Monish Ranjan Chatterjee, Nickolai Kukhtarev, Tatiana Kukhtareva

Electrical and Computer Engineering Faculty Publications

When a prerecorded cross-beam hologram is reconstructed (so-called edge-lit readout) with a uniform plane wave and a point source, the resulting exact solutions reveal Bessel-function-type diffracted beam profiles, which are fundamentally modified under weak propagational diffraction. The case of a profiled beam readout with propagational diffraction may be analyzed using a transfer function approach based on 2-D Laplace transforms. In a second series of investigations, dynamic readout from a cross-beam volume hologram recorded with two orthogonal uniform plane waves is considered for various dependences of the refractive index modulation with intensity. Typically, refractive index profiles that are proportional to the …

Map Estimation For Hyperspectral Image Resolution Enhancement Using An Auxiliary Sensor, Russell C. Hardie, Michael T. Eismann, Gregory L. Wilson

Electrical and Computer Engineering Faculty Publications

This paper presents a novel maximum a posteriori (MAP) estimator for enhancing the spatial resolution of an image using co-registered high spatial-resolution imagery from an auxiliary sensor. Here we focus on the use of high-resolution panchomatic data to enhance hyperspectral imagery. However, the estimation framework developed allows for any number of spectral bands in the primary and auxiliary image. The proposed technique is suitable for applications where some correlation, either localized or global, exists between the auxiliary image and the image being enhanced. To exploit localized correlations, a spatially varying statistical model, based on vector quantization, is used. Another important …

Volume Holographic Optical Elements, Ching-Cherng Sun, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

The final two papers are concerned with the analysis of novel holograms. Banerjee et al. investigate holographic recording and reconstruction for edge-lit holograms recorded in a 90-degree geometry. Various cases of recording and readout that incorporate propagational diffraction have been modeled. It is shown that the 90-degree geometry can result in beam shaping, as evidenced through preliminary experimental results with photorefractive lithium niobate. Nguyen et al. propose a new approach for designing computer-generated holograms. An artificial neural network is used to initiate the genetic algorithm so that the high computation cost of genetic algorithms for synthesizing holograms is significantly reduced …

Power-Stepped Protocol: Enhancing Spatial Utilization In A Clustered Mobile Ad Hoc Network, Chansu Yu, Kang G. Shin, Ben Lee

Electrical and Computer Engineering Faculty Publications

While most previous studies on mobile ad hoc networks (MANETs) rely on the assumption that nodes are randomly distributed in the network coverage area, this assumption is unlikely to hold, as nodes tend to be cluttered around hot spots like the site of an accident or disaster. We refer to this as a clustered layout. Intuitively, a MANET with the clustered layout may suffer from serious performance degradation due to the excessive collisions in congested hot spots and space underutilization of sparse areas. In this paper, we propose a power-controlled network protocol, called the power-stepped protocol (PSP), that maximizes the …

Evaluation Of Power Costs In Applying Tmr To Fpga Designs, Nathaniel Rollins, Michael J. Wirthlin, Paul S. Graham

Faculty Publications

Sponsorship: Los Alamos National Laboratory. Triple modular redundancy (TMR) is a technique commonly used to mitigate against design failures caused by single event upsets (SEUs). The SEU immunity that TMR provides comes at the cost of increased design area and decreased speed. Additionally, the cost of increased power due to TMR must be considered. This paper evaluates the power costs of TMR and validates the evaluations with actual measurements. Sensitivity to design placement is another important part of this study. Power consumption costs due to TMR are also evaluated in different FPGA architectures. This study shows that power consumption rises …

Network Anomaly Detection Using Management Information Base (Mib) Network Traffic Variables, Jun Li

Dissertations

In this dissertation, a hierarchical, multi-tier, multiple-observation-window, network anomaly detection system (NADS) is introduced, namely, the MIB Anomaly Detection (MAD) system, which is capable of detecting and diagnosing network anomalies (including network faults and Denial of Service computer network attacks) proactively and adaptively. The MAD system utilizes statistical models and neural network classifier to detect network anomalies through monitoring the subtle changes of network traffic patterns. The process of measuring network traffic pattern is achieved by monitoring the Management Information Base (Mifi) II variables, supplied by the Simple Network Management Protocol (SNMP) LI. The MAD system then converted each monitored …

Detection Of Denial Of Service Attacks Using Database Queries, Dmytro Zakhalyavko

Theses

In the current intrusion detection world, most intrusion detection systems output data into flat files. This project was conducted in order to improve intrusion detection data and alerts by writing them into a database system and analyzing them with SQL. A database plug-in was developed that helps to transition the data from an intrusion detection system to a database. Storing, analyzing, categorizing, and accessing data are major advantages and reasons for using databases in intrusion detection. Security analysts have to constantly perform the difficult task of sorting through a haystack of attack alerts, many of which turn out to be …

Spectrum Control And Iterative Coding For High Capacity Multiband Ofdm, Divaydeep Sikri

Theses

The emergence of Multiband Orthogonal Frequency Division Modulation (MB-OFDM) as an ultra-wideband (UWB) technology injected new optimism in the market through realistic commercial implementation, while keeping promise of high data rates intact. However, it has also brought with it host of issues, some of which are addressed in this thesis.

The thesis primarily focuses on the two issues of spectrum control and user capacity for the system currently proposed by the Multiband OFDM Alliance (MBOA). By showing that line spectra are still an issue for new modulation scheme (MB-OFDM), it proposes a mechanism of scrambling the data with an increased …

Optimal Sampling For Single-Tone Frequency Estimation, Travis E. Oliphant

Faculty Publications

Single-tone frequency estimation from irregularly spaced samples is analyzed. The ratio of the Cramr-Rao Bound (CRB) for regularly spaced samples to the bound for irregularly spaced samples is presented and shown to be a globally convex function. It's minima and maxima over the domain of interest are identified which reveals that improvements in the CRB can be obtained using non-equally-spaced samples. For a given sampling density, the best estimates of frequency are obtained when half of the samples are taken at one end of the total available interval and the remaining samples are taken at the other end.

Fabrication Of Solid Oxide Fuel Cells And Analysis Of Their Structure And Performance, Nai-Tao Yang, Bo Meng, Ru-Jun Yu, Xiao-Yao Tan

Journal of Electrochemistry

An intermediate temperature solid oxide fuel cell (IT-SOFC) was fabricated by co-copressing-sintering methods, and the electrolyte of Ce_0.8Gd_0.2O_1.9 (CGO) and cathode materials of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-α (LSCF) were prepared by sol-gel method. The effect of preparation methods on the microstructure of the prepared fuel cells was analyzed by SEM . It shows that the cells prepared by the co-pressing/co-sintering method possess a dense electrolyte layer and a compact interface between electrolyte and anode but a curved configuration, while those prepared by the colloidal technique have a flat configuration …

Preparation And Electrochemical Performance Of New Composite Seperators For Lithium-Ion Batteries, Hu Cheng, Hong-Yan Du, Yong Yang

Journal of Electrochemistry

New composite seperators for lithium ion batteries were prepared by coating PEO mixed with nanosize SiO₂ onto microporous polypropylene(PP) seperators. Highly conductive electrolytes were prepared by soaking them in an electrolyte solution. With these composite separators, the lithium ion cell consisting of Li anode and LiNi_0.8Co_0.2O₂ cathode were assembled. The high initial discharge capacity and good capacity retention were obtained through the cell.

Synthesis And Electrochemical Behavior Of Layered-Structure Limn1-XCrXO2, Jie Xiao, Hui Zhan, Yun-Hong Zhou

Journal of Electrochemistry

The Layered-structure LiMn_1-xCr_xO₂(x=0, 0.15) solid solution has been prepared by the rheological phase method. From the XRD results, undoped LiMnO₂ crystallized almost entirely in the orthorhombic phase while the structure of LiMn_0.85Cr_0.15O₂ belongs to monoclinic phase. TEM investigation shows that the final powder product consists of ultrafine spherical particles which are distributed homogeneously, with the average diameter ranging from 60 to 300nm. The initial discharge capacity of LiMn_0.85Cr_0.15O is much higher than that of undoped LiMnO₂. After 40 cycles, the capacity retention …

Electromagnetic Crosstalk Penalty In Serial Fiber Optic Modules, Xiaomin Jin, Keith D. Lystad, Musoke H. Sendaula

Electrical Engineering

Electromagnetic crosstalk poses a serious problem within today S advanced serial communication modules. A major detrimental effect is the degradation of receiver sensitivity in the presence of crosstalk noise. The mitigation of crosstalk penalty becomes increasingly more challenging as data rates increase for higher throughput and as module sizes shrink for increased port density. This paper is a study of the primary sources of crosstalk penalty in a 2.5 GB/s serial fiber optic transceiver and a 10Gb/s serial fiber optic transponder. A novel method for quantifying crosstalk penalty by observing a receiver’s bit-error-ratio (BER) versus transmitter to receiver signal phase …

Single And Multiple Surface Scatterings From Rough Surfaces, Chin-Yuan Hsieh, Shun-Hsyung Chang

Journal of Marine Science and Technology–Taiwan

The objective of this paper is to study the contributions of multiple scattering and compare it with those of the single scattering from randomly rough surfaces. The existing Kirchhoff, small perturbation and IEM scattering model cannot be used to predict the multiple scattering along the azimuth angle. In this paper we modify the IEM model by adding the phase terms in Green’s function and its derivative for multiple scattering. The function of phase term is significant to investigate the contribution of multiple scattering in the upward and downward directions. The contribution by multiple scattering is mainly based on the normalized …

An Examination Into The Statistics Of The Singular Vectors For The Multi-User Mimo Wireless Channel, Scott Nathan Gunyan

Theses and Dissertations

Many capacity and near-capacity achieving methods in multiple-input-multipleoutput (MIMO) wireless channels make use of the singular value decomposition (SVD) of the channel matrix. For the multi-user case, the SVD of the channel matrix for each user may result in right and left singular vectors that are similar between users. This proposes another descriptive characterization of the multi-user MIMO channel. Closely aligned singular vectors between any two users could reduce the achievable signaling rates of signal processing communication methods as one user would be more difficult to resolve in space-time from another. An examination into how this alignment can be described …

Electromagnetic Interference Of System On Package, Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI …

A New Calibration Method For Current Probes, Ramachandran Chundru, David Pommerenke, Sunitha Chandra

Electrical and Computer Engineering Faculty Research & Creative Works

EMC engineers often use current probes to detect common mode currents. It is necessary to characterize the probes up to Giga Hertz frequencies. Existing calibration methods for current clamps suffer from the problem of not directly measuring the current within the current clamp. Instead they either reconstruct the current from measurements at other locations or they use assumptions regarding the geometry which allows them to use a current that is measured at a different location without applying a mathematical correction. The proposed method overcomes these disadvantages by directly measuring the current at the center of the current clamp. This paper …

Static And Quasi-Dynamic Load Balancing In Parallel Fdtd Codes For Signal Integrity, Power Integrity, And Packaging Applications, Sarah A. Seguin, Michael A. Cracraft, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The Finite-Difference Time-Domain (FDTD) method is a robust technique for calculating electromagnetic fields, but practical problems, involving complex or large geometries, can require a long time to calculate on any one single-processor computer. One computer with many processors or many single-processor computers can reduce the computation time. However, some FDTD cell types, e.g., PML cells, require more computation time than others. Thus, the size and shape of the individual process allocations can significantly influence the computation time. This paper addresses these load balancing issues with static and quasi-dynamic approaches. The Message-Passing Interface (MPI) library is applied to a three-dimensional (3D) …

Unitary Space-Time Transmit Diversity For Multiple Antenna Self-Interference Suppression, Adam Lane Anderson

Theses and Dissertations

A common practice for government defense agencies and commercial aeronautical companies is to use dual antennas on test flight air vehicles in order to overcome occlusion issues during high-speed telemetric maneuvers. The dual antennas, though never being masked at the same time, unfortunately lead to a drastic increase in nulls in the signal pattern. The result of this interference pattern can be compared to the effect of fading in a multiple-input multiple-output (MIMO) multi-path scattering environment. Confidence in this comparison leads to the use of unitary space-time MIMO codes to overcome the signal self-interference. The possibility and performance of several …

A Ray-Based Investigation Of The Statistical Characteristics And Efficient Representation Of Multi-Antenna Communication Channels, Gus Ryan German

Theses and Dissertations

Multi-antenna communication systems are attracting research interest as a means to increase the information capacity, reliability, and spectral efficiency of wireless information transfer. Ray-tracing methods predict the behavior of wireless channels using a model of the propagation environment and are a low-cost alternative to direct measurements. We use ray tracing simulations to validate the statistical time and angle of arrival characteristics of an indoor multipath channel and compare model parameter estimates with estimates derived from channel sounding measurements. Ray tracing predicts the time and angle clustering of multipaths observed in the measurements and provides model parameter estimates which are closely …

Architectures For Symbol Timing Synchronization In Mimo Communications, Kejing Liu

Theses and Dissertations

Maximum likelihood symbol timing estimation for communication over a frequency non-selective MIMO fading channel is developed. The cases of known data (data-aided estimation) and unknown data (non-data-aided estimation) together with known channel and unknown channel are considered. The analysis shows that the log-likelihood functions and their approximations can be interpreted as SISO log-likelihood functions operating on each of the receive antennas. Previously published symbol timing estimators are shown to be special cases of the more general framework presented. Architectures based on both block processing and sequential processing using a discrete-time phase-locked loop are summarized. Performance examples over a MIMO channel …

Wideband Channel Characterization For Mimo Scenario, Justin T. Holzer

Theses and Dissertations

Because broadband wireless systems benefit from accurate channel characterization, there is growing interest in broadband wireless multiple-input multiple-output (MIMO) channel models. This thesis verifies the suitability of the Saleh Valenzuela with Angle (SVA) model for wideband MIMO communication models. While recent wideband MIMO measurements have been obtained by switching a single transmit/receive pair over all possible antenna pair combinations, a simultaneous probing system is superior because of the time required for the antenna-switching channel measurements. This work provides two different wideband channel estimation algorithms based on simultaneous transmission from and reception on all antennas. Simulated data from an electromagnetic ray …

Consensus Seeking, Formation Keeping, And Trajectory Tracking In Multiple Vehicle Cooperative Control, Wei Ren

Theses and Dissertations

Cooperative control problems for multiple vehicle systems can be categorized as either formation control problems with applications to mobile robots, unmanned air vehicles, autonomous underwater vehicles, satellites, aircraft, spacecraft, and automated highway systems, or non-formation control problems such as task assignment, cooperative transport, cooperative role assignment, air traffic control, cooperative timing, and cooperative search. The cooperative control of multiple vehicle systems poses significant theoretical and practical challenges. For cooperative control strategies to be successful, numerous issues must be addressed. We consider three important and correlated issues: consensus seeking, formation keeping, and trajectory tracking. For consensus seeking, we investigate algorithms and …

A Framework For Trajectory Based Visual Event Retrieval, Ilker Ersoy, Filiz Bunyak, S. R. Subramanya

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a framework of a system for the query and retrieval of video data based on video events in huge video repositories. the events are formulated using domain-independent event primitives which are represented by spatio-temporal relationships between objects in the video scenes. Complex events are expressible as combinations of simpler events. This facilitates support of event queries from a variety of points of view. in addition, the framework is expected to provide adaptability of the framework to multiple domains.

Performance Evaluation Of Block-Based Motion Estimation Algorithms And Distortion Measures, S. R. Subramanya, Hiral Patel, Ilker Ersoy

Electrical and Computer Engineering Faculty Research & Creative Works

Motion estimation is an important component in video compression schemes which impacts the encoder performance and the quality of the reconstructed video sequence. Block-Based techniques are the most popular among the several motion estimation techniques used in practice due to their simplicity allowing efficient hardware implementations. the quality of motion predicted frame and the speed of motion vector computation are the primary measures of performance of motion estimation schemes. the video compression standards only specify the syntax of the bitstream and not any specifics of the motion estimation techniques. Thus, the knowledge of the workings and performance of commonly used …

A Suite Of Secure Multi-Party Computation Algorithms For Solving Distributed Constraint Satisfaction And Optimization Problems, Marius C. Silaghi

Electrical Engineering and Computer Science Faculty Publications

Privacy requirements can be modeled within the distributed constraint satisfaction framework, where the constraints are secrets of the participants. In [20] we introduced a first technique allowing agents to solve distributed constraint problems (DisCSPs), without revealing anything and without trusting each other or some server. The first technique we propose now, MPC-DisCSP2, is a dm times improvement for m variables of domain size d. A second technique we propose, MPC-DisCSP3, has a similar complexity as MPD-DisCSP2, a little slower in the worst case, but guarantees that the returned solutions are picked according to a uniform distribution over the total set …