Engineering Commons^™

Wide-Gain Range Bridgeless Pfc Modified Sepic Rectifier, Ahmed Mohammed Ahmed Al Gabri

Theses

With the increasing demand for power from the ac line and more strict limits for power quality, power factor correction has gained great attention in recent years. AII basic power converter topologies, such as Boost, Buck, Buck-Boost, and their variations, can be used to realize active PFC techniques. In this research, a new bridge less rectifier that operates with high power factor and high efficiency is investigated targeting LED and battery charging applications. The new topology is a high-power-factor rectifier, which is suitable for universal line base on a modified version of the single-ended primary inductance converter (SEPIC) operating in …

Crystallographic Orientation Of The Ε → Α' Martensitic (Athermal) Transformation In A Femnalsi Steel, S. T. Pisarik, D. C. Van Aken

Materials Science and Engineering Faculty Research & Creative Works

The presence of a thermal ε- and α-martensite (α') in the as-cast structure of a Fe-_0.08C-_1.95Si-_15.1Mn-_1.4Al-_0.017N alloy has been revealed by electron backscattered diffraction analysis. The alloy exhibited two a thermal martensitic transformation described by γ → α' and γ → ε → α'. The Shoji-Nishiyama orientation relationship was observed between γ-austenite and ε-martensite, while α-martensite nucleated from γ-austenite exhibited a Kurdjumov-Sachs orientation relationship. Six crystallographic variants of α-martensite consisting of three twin-related variant pairs were observed in ε-bands. A planar parallelism of {0001}ε || {110}α' and a directional relation …

Multipacting Optimization Of A 750 Mhz Rf Dipole, A. Castilla, J. R. Delayen

Physics Faculty Publications

Crab crossing schemes have been proposed to re-instate luminosity degradation due to crossing angles at the interaction points in next generation colliders to avoid the use of sharp bending magnets and their resulting large synchrotron radiation generation, highly undesirable in the detector region. The rf dipole has been considered for a different set of applications in several machines, both rings and linear colliders. We present in this paper a study of the effects on the multipacting levels and location depending on geometrical variations on the design for a crabbing/deflecting application in a high current (3/0.5 A), high repetition (750 MHz) …

Cryogenic Testing Of High-Velocity Spoke Cavities, C. S. Hopper, Hyekyoung Park, J. R. Delayen

Physics Faculty Publications

Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, β0 = 0.82 single-spoke cavity and a 500 MHz, β0 = 1 double-spoke cavity.

Ieee Cibcb 2014-Computational Intelligence In Bioinformatics And Computational Biology [Conference Reports], Steven Corns

Engineering Management and Systems Engineering Faculty Research & Creative Works

The 2014 Conference on Computational Intelligence in Bioinformatics and Computational Biology (CIBCB) was held at the Hilton Hawaiian Village, Honolulu, from May 21-25. The papers presented at the conference covered the full range of computational intelligence techniques and applications. James Hughes from Brock University received the best student paper award from General Chair Steven Corns for his paper titled, 'Recentering and Restarting Genetic Algorithms Variations for DNA Fragment Assembly.' The best overall paper was awarded to Jennifer Hallinan, Owen Gilfellon, Goksel Misirli and Anil Wipat, all of Newcastle University, for their work 'Tuning Receiver Characteristics in Bacterial Quorum Communication: An …

Part Viii: Health Care Analytics: Preface, Cilan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

No abstract provided.

A Study Of The Effect Of Basic Network Characteristics On System-Of-System Failure Propagation, Charles O. Adler, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Real life examples of large system level failures in complex networked system are fairly common, with national and regional level power grids providing numerous cases where local failures have resulted in broad systemic failures. As large networked systems-of-systems are increasingly common, their susceptibility to large scale failures is of significant interest. This paper presents the results of a study using a simple model to investigate the impacts of basic architecture characteristics on the spread of failures through a system-of-system after an initial failure occurs. The study reported here uses a non-symmetric inter-grid only failure model to investigate the sensitivity of …

A Hybrid Neuro-Fuzzy Model To Forecast Inflation, David Lee Enke, Nijat Mehdiyev

Engineering Management and Systems Engineering Faculty Research & Creative Works

One of the key issues in constructing monetary policy is accurate prediction of the inflation level. The complex behavior and non-linear nature of the financial markets makes it hard to forecast the inflation rate precisely. This paper introduces a hybrid model that attempts to forecast the inflation rate with a combination of a subtractive clustering technique and a fuzzy inference neural network to overcome the shortcomings of the individual methodologies. Selected macroeconomic factors were used to predict the historical CPI data from the US Markets. The results of the proposed hybrid model are measured in RMSE.

Volatility Forecasting Using A Hybrid Gjr-Garch Neural Network Model, Soheil Almasi Monfared, David Lee Enke

Engineering Management and Systems Engineering Faculty Research & Creative Works

Volatility forecasting in the financial markets, along with the development of financial models, is important in the areas of risk management and asset pricing, among others. Previous testing has shown that asymmetric GARCH models outperform other GARCH family models with regard to volatility prediction. Utilizing this information, three popular Neural Network models (Feed-Forward with Back Propagation, Generalized Regression, and Radial Basis Function) are implemented to help improve the performance of the GJR (1,1) method for estimating volatility over the next forty-four trading days. During training and testing, four different economic cycles have been considered between 1997-2011 to represent real and …

Joint Decisions On Inventory Replenishment And Emission Reduction Investment Under Different Emission Regulations, Ayşegül Toptal, Haşim Özlü, Dinçer Konur

Engineering Management and Systems Engineering Faculty Research & Creative Works

Carbon emission regulation policies have emerged as mechanisms to control firms' carbon emissions. To meet regulatory requirements, firms can make changes in their production planning decisions or invest in green technologies. In this study, we analyze a retailer's joint decisions on inventory replenishment and carbon emission reduction investment under three carbon emission regulation policies. Particularly, we extend the economic order quantity model to consider carbon emissions reduction investment availability under carbon cap, tax and cap-and-trade policies. We analytically show that carbon emission reduction investment opportunities, additional to reducing emissions as per regulations, further reduce carbon emissions while reducing costs. We …

Multi-Agent Based Architecture For Acknowledged System Of Systems, Siddhartha Agarwal, Lou E. Pape, Nil Kilicay-Ergin, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

Negotiation and collaboration issues in large organizations, with centralized control, across the globe, are becoming more complex with each passing day. The Acknowledged System of Systems (SoS) is a new approach that addresses some of these issues in a systematic, efficient manner. This paper proposes a hierarchical architectural framework to support Acknowledged SoS architecting and analysis for a Department of Defense (DoD) Acquisition process. A major challenge of the successful planning and evolution of an Acknowledged SoS is the lack of understanding of the impact of presence or absence of a system and its interface with another constituent system on …

Rmse-Elm: Recursive Model Based Selective Ensemble Of Extreme Learning Machines For Robustness Improvement, Bo Han, Bo He, Mengmeng Ma, Tingting Sun, Tianhong Yan, Amaury Lendasse

Engineering Management and Systems Engineering Faculty Research & Creative Works

For Blended Data, the Robustness of Extreme Learning Machine (Elm) is So Weak Because the Coefficients (Weights and Biases) of Hidden Nodes Are Set Randomly and the Noisy Data Exert a Negative Effect. to Solve This Problem, a New Framework Called "RMSE-ELM" is Proposed in This Paper. It is a Two-Layer Recursive Model. in the First Layer, the Framework Trains Lots of Elms in Different Ensemble Groups Concurrently and Then Employs Selective Ensemble Approach to Pick Out an Optimal Set of Elms in Each Group, Which Can Be Merged into a Large Group of Elms Called Candidate Pool. in the …

Thermotropic Phase Boundaries In Classic Ferroelectrics, Tom T. A. Lummen, Yijia Gu, Jianjun Wang

Materials Science and Engineering Faculty Research & Creative Works

High-performance piezoelectrics are lead-based solid solutions that exhibit a so-called morphotropic phase boundary, which separates two competing phases as a function of chemical composition; as a consequence, an intermediate low-symmetry phase with a strong piezoelectric effect arises. In search for environmentally sustainable lead-free alternatives that exhibit analogous characteristics, we use a network of competing domains to create similar conditions across thermal inter-ferroelectric transitions in simple, lead-free ferroelectrics such as BaTiO₃ and KNbO₃. Here we report the experimental observation of thermotropic phase boundaries in these classic ferroelectrics, through direct imaging of low-symmetry intermediate phases that exhibit large enhancements …

Nanocrystalline Rare Earth Phosphates From Glass Dissolution And Precipitation Reactions, Jaime George, Colin Ryan, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

A novel method is employed for the formation of rare earth phosphate solid solution compounds with unique mesoscopic structures. Europium- And lanthanum-doped sodium borate glass microspheres and particles, ranging in sizes from 50 to 300 μm, were reacted in 0.25 M K₂HPO₄ solution to form hollow spheres of nanocrystalline rare earth phosphate compounds by dissolution-precipitation reactions. The initially X-ray amorphous precipitated rare earth phosphate materials were heat-treated at 700°C for 2 h to form nanocrystalline compounds. Differential thermal analysis (DTA) experiments yield an average activation energy for crystallization of 394 ± 26 kJ/mol. X-ray diffraction (XRD) data …

A Preliminary Study Of Deformation Behavior Of Friction Stir Welded Ti-6al-4v, Jiye Wang, Jianqing Su, Rajiv S. Mishra, Ray Xu, John A. Baumann

Materials Science and Engineering Faculty Research & Creative Works

A preliminary study of deformation behavior of friction stir welded (FSW) Ti-6Al-4V was performed using two different tools with cylindrical and stepped spiral pin design for the welding process. The nugget regions experienced temperature above β transus and the matrix transformed to fine acicular α during cooling of the nugget. By using stepped spiral pin design, a local region with much refined grain structure and significant tool debris particles were observed. Room temperature tensile test showed increased strength and decreased ductility in the material from this region. Fractographic analysis revealed that tool debris particles served as void nucleation sites. Tensile …

An Evaluation Of Creep Behaviour In Friction Stir Welded Ma754 Alloy, Jiye Wang, Wei Yuan, Rajiv S. Mishra, Indrajit Charit

Materials Science and Engineering Faculty Research & Creative Works

Effect of friction stir welding (FSW) on microstructure and creep properties of oxide dispersion strengthened (ODS) alloy MA754 were investigated. Fine-grained microstructure developed in the weld zone. TEM results showed some degree of particle agglomeration as a result of intense material flow. Creep tests of the FSW material were carried out at 973 and 1073 K. Power law creep behavior was observed with stress exponent values of 6.9 and 6.3 at 973 and 1073 K, respectively. The results were compared to those of the as-received material. Creep resistance of FSW material was lower than that of as-received material associated with …

Spinel-Based Refractories For Improved Performance In Coal Gasification Environments, James G. Hemrick, Beth Armstrong, Angela Rodrigues-Schroer, Dominick Colavito, Jeffrey D. Smith

Materials Science and Engineering Faculty Research & Creative Works

Oak Ridge National Laboratory, in collaboration with Minteq International, Inc., Missouri University of Science and Technology and refractory end users, has developed novel refractory systems and techniques to reduce energy consumption of refractory lined vessels. The objective of this U.S. DOE funded project was to address the need for innovative refractory compositions by developing MgO-Al₂O₃ spinel gunnable refractory compositions utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. Materials have been developed specifically for coal gasification environments and work has been performed to develop and apply low cost coatings using a colloidal approach for …

Role Of Surface Chemistry In Nanoscale Electrokinetic Transport, Secuk Atalay

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation work presents the efforts to study the electrofluidics phenomena, with a focus on surface charge properties in nanoscale systems with the potential applications in imaging, energy conversion, ultrafiltration, DNA analysis/sequencing, DNA and protein transport, drug delivery, biological/chemical agent detection and micro/nano chip sensors.

Since the ion or molecular or particle transport and also liquid confinement in nano-structures are strongly dominated by the surface charge properties, in regards of the fundamental understanding of electrofluidics at nanoscale, we have used surface charge chemistry properties based on 2-pK charging mechanism. Using this mechanism, we theoretically and analytically showed the surface charge …

Electric-Field Induced Ferromagnetic Phase In Paraelectric Antiferromagnets, Maya D. Glinchuk, Eugene A. Eliseev, Yijia Gu, Long-Qing Chen, Venkatraman Gopalan, Anna N. Morozovska

Materials Science and Engineering Faculty Research & Creative Works

The phase diagram of a quantum paraelectric antiferromagnet EuTiO₃3 under an external electric field is calculated using Landau-Ginzburg-Devonshire theory. The application of an electric field E in the absence of strain leads to the appearance of a ferromagnetic (FM) phase due to the magnetoelectric (ME) coupling. At an electric field greater than a critical field, E_cr, the antiferromagnetic (AFM) phase disappears for all considered temperatures, and FM becomes the only stable magnetic phase. The calculated value of the critical field is close to the values reported recently by Ryan et al. [Nat. Commun. 4, 1334 (2013)10.1038/ncomms2329] …

Hybrid-Cascade Coupled-Line Phasers For High-Resolution Radio-Analog Signal Processing, Thomas Paradis, Shulabh Gupta, Qingfeng Zhang, Li (Lijun) J. Jiang, Christophe Caloz

Electrical and Computer Engineering Faculty Research & Creative Works

A hybrid-cascade (HC) coupled-line phaser configuration is presented to synthesize enhanced group delay responses for high-resolution radio-analog signal processing. Using exact analytical transfer functions, the superiority of HC coupled-line phasers over conventional transversally cascaded C-section phasers is demonstrated and verified using full-wave simulations. © 2014 Wiley Periodicals, Inc.

A Kalman Filter With Individual Control Factors For Echo Cancellation, Constantin Paleologu, Jacob Benesty, Silviu Ciochinǎ, Steven L. Grant

Electrical and Computer Engineering Faculty Research & Creative Works

In echo cancellation, the main goal is to recover the near-end signal from the error signal of the adaptive filter, which identifies the echo path. In this context, the Kalman filter represents a very appealing choice, since its basic criterion follows the minimization of the system misalignment (instead of the usual error-based cost function). In this paper, we propose a Kalman filter with individual control factors, in terms of using a different level of uncertainty for each coefficient of the filter. As compared to the basic Kalman filter (which imposes the same uncertainty for all the coefficients of the impulse …

On The Deployment Of On-Chip Noise Sensors, Tao Wang, Chun Zhang, Jinjun Xiong, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Runtime noise management systems can enforce power integrity without significantly increasing design margins. These systems typically respond to on-chip noise sensors to accurately capture voltage emergencies. Unfortunately, it remains an open problem in the literature how to optimally place a given number of noise sensors for best voltage emergency detection, or how to best set the threshold voltage for these sensors. In this paper, we formally define the problem of noise sensor placement along with a novel sensing quality metric to be maximized. We then put forward an efficient algorithm to solve it, which is proven to attain the best …

Critical Path Monitor Enabled Dynamic Voltage Scaling For Graceful Degradation In Sub-Threshold Designs, Yu Guang Chen, Tao Wang, Kuan Yu Lai, Wan Yu Wen, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

Sub-threshold designs play an important role in energy constrained applications. In those designs, path delays depend exponentially on threshold voltage/temperature. As such, dynamic configurations at runtime are desired for best trade-off between operating power and performance. Unfortunately, most existing works only consider either process or temperature variations but not both, resulting in sub-optimal configurations or even functional failures. Moreover, little study has been performed on the graceful degradation of sub-threshold designs, which is important in the presence of drastic delay variations. Towards this, we present a novel critical path monitor based dynamic voltage scaling scheme. Considering both process and temperature …

An Accurate Frame Error Rate Approximation Of Coded Diversity Systems With Non-Identical Diversity Branches, Gang Wang, Jingxian Wu, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an accurate approximation of the frame error rate (FER) of coded wireless communication systems with receiver diversity, such as single-input multiple-output (SIMO) systems with maximum ratio combining (MRC) or hybrid automatic repeat request (HARQ) systems with Chase combining. The signals at different diversity branches experience independent but non-identically distributed Rayleigh fading. The FER approximation is obtained with a threshold-based method. Specifically, the threshold value, which is critical to the FER approximation accuracy, is modeled as a linear function of the frame length in the log-domain, with the slope and intercept of the linear function determined by the …

Fixed Final-Time Near Optimal Regulation Of Nonlinear Discrete-Time Systems In Affine Form Using Output Feedback, Qiming Zhao, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the fixed final-time near optimal output regulation of affine nonlinear discrete-time systems with unknown system dynamics is considered. First, a neural network (NN)-based observer is proposed to reconstruct both the system state vector and control coefficient matrix. Next, actor-critic structure is utilized to approximate the time-varying solution of the Hamilton-Jacobi-Bellman (HJB) equation or value function. To satisfy the terminal constraint, a new error term is defined and incorporated in the NN update law so that the terminal constraint error is also minimized over time. A NN with constant weights and time-dependent activation function is employed to approximate …

Converting An Old Machines Lab Into A Functioning Power Network With A Microgrid For Education, Md Rasheduzzaman, Badrul H. Chowdhury, Shyam Bhaskara

Electrical and Computer Engineering Faculty Research & Creative Works

As colleges prepare or revise their power engineering courses to include discussions on the smart grid, the microgrid, distributed energy sources and renewable energy resources, the need for new material suitable for inclusion in a typical 4-year undergraduate engineering course has never been more obvious. Toward this effort, an old machines lab was remodeled and converted into a small power network that can be operated in both grid-connected and grid-islanded microgrid modes. The intent of this paper is to devise laboratory experiments to supplement a course in conventional power systems analysis at the undergraduate level. During the remodeling process, two …

Optimization Of Transmission Conditions In Waveform Relaxation Techniques For Rc Circuits, Mohammad D. Al-Khaleel, Martin J. Gander, Albert E. Ruehli

Electrical and Computer Engineering Faculty Research & Creative Works

Waveform relaxation techniques have become increasingly important with the wide availability of parallel computers with a large number of processors. A limiting factor for classical waveform relaxation, however, is the convergence speed for an important class of problems, especially if long time windows are considered. In contrast, the optimized waveform relaxation algorithm discussed in this paper is well suited to address this problem. Today several numerical analyses have shown that optimized waveform relaxation algorithms can overcome slow convergence over long time windows. However, the optimized waveform relaxation techniques require the determination of optimized parameters. In this paper, we present a …

Adaptive Neural Network-Based Optimal Control Of Nonlinear Continuous-Time Systems In Strict-Feedback Form, H. Zargarzadeh, T. Dierks, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper focuses on neural network (NN) based optimal control of nonlinear continuous-time systems in strict-feedback form when the system dynamics are known by using an adaptive backstepping approach. A single NN-based adaptive approach is designed to learn the solution of the infinite horizon continuous-time Hamilton-Jacobi-Bellman (HJB) equation while the corresponding optimal control input that minimizes the HJB equation is calculated in a forward-in-time manner without using value and policy iterations. First, the optimal control problem is solved for a generic multi-input and multi-output nonlinear system with a state feedback approach. Then the approach is extended to a single-input and …

Efficient Implementation Of Iterative Multi-Input-Multi-Output Orthogonal Frequency-Division Multiplexing Receiver Using Minimum-Mean-Square Error Interference Cancellation, Bing Han, Zengli Yang, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

An efficient hardware implementation scheme is proposed for iterative multi-input-multi-output orthogonal frequency division multiplexing receiver which includes an MMSE-IC (minimum-mean-square error interference cancellation) detector, a channel estimator, a low-density parity-check (LDPC) decoder and other supporting modules. The proposed implementation uses the QR decomposition (QRD) of the complex-valued matrices with four coordinate rotation digital computer (CORDIC) cores and a back substitution to solve the MMSE-IC equations while the existing systolic array architectures require 15-38 CORDIC cores to achieve a similar throughput. The proposed 4-CORDIC QRD architecture can be configured as a 16-matrix or a 64-matrix pipelining by using a different number …

An Online Outlier Identification And Removal Scheme For Improving Fault Detection Performance, Hasan Ferdowsi, Sarangapani Jagannathan, Maciej Jan Zawodniok

Electrical and Computer Engineering Faculty Research & Creative Works

Measured data or states for a nonlinear dynamic system is usually contaminated by outliers. Identifying and removing outliers will make the data (or system states) more trustworthy and reliable since outliers in the measured data (or states) can cause missed or false alarms during fault diagnosis. In addition, faults can make the system states nonstationary needing a novel analytical model-based fault detection (FD) framework. In this paper, an online outlier identification and removal (OIR) scheme is proposed for a nonlinear dynamic system. Since the dynamics of the system can experience unknown changes due to faults, traditional observer-based techniques cannot be …