Engineering Commons^™

Evolutionary Algorithms, Markov Decision Processes, Adaptive Critic Designs, And Clustering: Commonalities, Hybridization And Performance, Donald C. Wunsch, Samuel A. Mulder

Electrical and Computer Engineering Faculty Research & Creative Works

We briefly review and compare the mathematical formulation of Markov decision processes (MDP) and evolutionary algorithms (EA). In so doing, we observe that the adaptive critic design (ACD) approach to MDP can be viewed as a special form of EA. This leads us to pose pertinent questions about possible expansions of the methodology of ACD. This expansive view of EA is not limited to ACD. We discuss how it is possible to consider the powerful chained Lin Kernighan (chained LK) algorithm for the traveling salesman problem (TSP) as a degenerate case of EA. Finally, we review some recent TSP results, …

Using Near-Field Scanning To Predict Radiated Fields, Jin Shi, Michael A. Cracraft, Jianmin Zhang, Richard E. Dubroff, Kevin P. Slattery, Masahiro Yamaguchi

Electrical and Computer Engineering Faculty Research & Creative Works

Near-field scanning has often been used to measure and characterize magnetic fields surrounding individual integrated circuits (IC) and high speed digital electronic circuits. The paper describes the use of near-field scanning data, performed in a typical laboratory bench top environment, to predict radiated electromagnetic interference (EMI) in a typical product environment. The product environment may include enclosures and apertures. The approach begins by acquiring sufficient near-field scanning data to allow representation of an unintentional radiating source by an equivalent surface current distribution. The equivalent current distribution is used as a source in numerical full wave modeling. The agreement between direct …

Spectrum Visualization And Measurement Of Power Parameters Of Microwave Wide-Band Noise, Marina Koledintseva, Alexander A. Kitaytsev, V. A. Konkin, V. Radchenko

Electrical and Computer Engineering Faculty Research & Creative Works

A method for an adequate visualization of a microwave intense noise spectrum envelope in a wide frequency range (several octaves), measurement of its power parameters, and detection of a narrow-band signal with unknown frequency and power against the noise background is presented. This method is based on an application of a nonheterodyne principle of microwave frequency (and power) conversion using a gyromagnetic converter, which operates in two regimes in turn: the resonance detection and the cross-multiplication. A block scheme and an operation of a two-channel measuring device combining the mentioned functions are discussed.

Optimal Beaver Population Management Using Reduced Order Distributed Parameter Model And Single Network Adaptive Critics, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using a distributed parameter model for beaver population that accounts for their spatial and temporal behavior, an optimal control for a desired distribution of the animals is presented. Optimal solutions are obtained through a "single network adaptive critic" (SNAC) neural network architecture. The objective of this research is to design an "optimal" beaver harvesting scheme for a region of interest.

A Preliminary Study Of Maximum System-Level Crosstalk At High Frequencies For Coupled Transmission Lines, H. Weng, Daryl G. Beetner, Todd H. Hubing, R. Wiese, J. Mccallum, Xiaopeng Dong

Electrical and Computer Engineering Faculty Research & Creative Works

Simple formulas were derived to quickly estimate maximum crosstalk between wires in a harness at high frequencies, where the length of circuits is comparable with or greater than the wavelength of the signals of interest. Formulas were derived from multi-conductor transmission line theory. When the source and load resistances are either both large or both small compared to the characteristic impedance of the transmission line, maximum coupling is shown to be given by approximately X_MAX = C_m / (C₂₂ + C_m). A similar equation was found for the case where the load impedances are matched. …

Characterization Of Human Metal Esd Reference Discharge Event And Correlation Of Generator Parameters To Failure Levels-Part Ii: Correlation Of Generator Parameters To Failure Levels, Kai Wang, David Pommerenke, Ramachandran Chundru, Thomas Van Doren, Jiu Sheng Huang, Federico Centola

Electrical and Computer Engineering Faculty Research & Creative Works

Most electrostatic discharge (ESD) generators are built in accordance with the IEC 61000-4-2 specifications. It is shown, that the voltage induced in a small loop correlates with the failure level observed in an ESD failure test on the systems comprised of fast CMOS devices, while rise time and derivative of the discharge current did not correlate well. The electric parameters of typical ESD generators and ESD generators that have been modified to reflect the current and field parameters of the human metal reference event are compared and the effect on the failure level of fast CMOS electronics is investigated. The …

Distributed Power Control Of Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel distributed power control (DPC) scheme for cellular networks in the presence of radio channel uncertainties such as path loss shadowing, and Rayleigh fading is presented. Since these uncertainties can attenuate the received signal strength and can cause variations in the received Signal-to-lnterference ratio (SIR), the proposed DPC scheme maintains a target SIR at the receiver provided the uncertainty is slowly varying with time. The DPC estimates the time varying nature of the channel quickly and uses the information to arrive at a suitable transmitter power value . Further, the standard assumption of a constant interference during a link's …

Dynamic Optimization Of A Multimachine Power System With A Facts Device Using Identification And Control Objectnets, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This work presents a novel technique for dynamic optimization of the electric power grid using brain-like stochastic identifiers and controllers called ObjectNets based on neural network architectures with recurrence. ObjectNets are neural network architectures developed to identify/control a particular object with a specific objective in hand. The IEEE 14 bus multimachine power system with a FACTS device is considered in this paper. The paper focuses on the combined minimization of the terminal voltage deviations and speed deviations at the generator terminals and the bus voltage deviation at the point of contact of the FACTS device to the power network. Simulation …

Ergodic Capacity Of Doubly Selective Rayleigh Fading Mimo Channels, Chengshan Xiao, Y. Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

The ergodic capacity is investigated for doubly selective (frequency selective and time varying) MIMO Rayleigh fading channels. A closed form formula is derived that quantifies the effect of the ISI fading on the ergodic capacity into an ISI degradation factor. It is discovered that, in general frequency selective MIMO channels, the inter-tap correlations of the ISI fading will reduce the ergodic capacity comparing to the frequency flat fading channel. Only in the special case when the ISI fading does not have inter-tap correlations will the ergodic capacity be the same as that of the frequency flat channel. This new formula …

Optical Characterization Of Ceramic Thin Films: Applications In Low-Temperature Solid Oxide Fuel-Cell Materials Research, B. P. Gorman, V. Petrovsky, Harlan U. Anderson, T. Petrovsky

Materials Science and Engineering Faculty Research & Creative Works

Characterization of thin film solid oxide fuel-cell materials can be difficult due to the range of porosities in electrodes and electrolytes as well as the nano-sized pores and particles. in this study, optical characterization techniques such as ultraviolet-visible transmission and reflection spectrophotometry are illustrated as methods for achieving information about the film density from the film refractive index as well as the film thickness. These techniques were used to investigate the sintering process of colloidal CeO₂ on sapphire substrates and polymeric precursor-derived ZrO₂:16%Y (YSZ) thin films on silicon over the temperature range 400-1000 °C, and the results …

Prediction Of Rotor Position At Standstill And Flying Shaft Conditions In Switched Reluctance Machines, M. Krishnamurthy, C. S. Edrington, Babak Fahimi

Electrical and Computer Engineering Faculty Research & Creative Works

Development of a reliable, smooth, and precise position sensor less startup routine is an integral part of the Switched Reluctance Machine (SRM) control. the proposed sensor less startup method presented in this paper represents high grade performance and does not require additional hardware or memory. Further, the proposed sensor less technique is extended to flying shaft conditions. These capabilities are highly demanded by automotive applications such as starter/alternator and electric power steering systems. an assessment of the impact of motor parameters and diagnostic signal measurement on the quality of the sensor less startup method is also included. This will help …

Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, P. He, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel neural network (NN) -Based output feedback controller with magnitude constraints is designed to deliver a desired tracking performance for a class of multi-input-multi-output (MIMO) discrete-time strict feedback nonlinear systems. Reinforcement learning in discrete time is proposed for the output feedback controller, which uses three NNs: 1) a NN observer to estimate the system states with the input-output data; 2) a critic NN to approximate certain strategic utility function; and 3) an action NN to minimize both the strategic utility function and the unknown dynamics estimation errors. the magnitude constraints are manifested as saturation nonlinearities in the output feedback …

Mixing Electromagnetic And Electrical Circuit Simulations, W. C. Chew, Y. H. Chu, L. (Lijun) J. Jiang, I. T. Chiang, Y. C. Pan, J. S. Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Airframe Noise Modeling Appropriate For Multidisciplinary Design And Optimization, Serhat Hosder, Bernard Grossman, Joseph A. Schetz, William H. Mason

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Trailing Edge Noise Metric has been developed for constructing response surfaces that may be used for optimization problems involving aerodynamic noise from a clean wing. The modeling approach includes a modified version of a theoretical trailing edge noise prediction and utilizes a high fidelity CFD (RANS) code with a two-equation turbulence model to obtain the characteristic velocity and length scales used in the noise model. The noise metric is not the absolute value of the noise intensity, but an accurate relative noise measure as shown in the validation studies. Parametric studies were performed to investigate the effect of the …

Analysis Of Jet-Wing Distributed Propulsion From Thick Wing Trailing Edges, Serhat Hosder, Joseph A. Schetz, Vance Dippold

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Conventional airliners use two to four engines in a Cayley-type arrangement to provide thrust, and the thrust is concentrated right behind the engine. Distributed propulsion is the idea of redistributing the thrust across most, or all, of the wingspan of an aircraft. This can be accomplished by using several large engines and using a duct to spread out the exhaust flow to form a jet-wing or by using many small engines spaced along the span of the wing. Jet-wing distributed propulsion was originally suggested as a way to improve propulsive efficiency. A previous study at Virginia Tech assessed the potential …

Characterization And Modeling Of Local Electromechanical Response In Stress-Biased Piezoelectric Actuators, N. Navapan-Traiphol, Robert W. Schwartz, Daniel S. Stutts, J. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Numerous investigators have explored the factors that contribute to the high electromechanical performance of stress-biased actuators with particular attention being given to the importance of the extrinsic (domain wall translation) response mechanism. Based on the variation in lateral stress through the thickness of the piezoelectric layer within these devices, it has been suggested that the piezoelectric coefficient varies as a function of position within the layer, though no direct evidence has been previously presented. In this study, the results of Moire interferometry investigations of local strains within these devices are reviewed. The technique permits effective depth-profiling of local deformations at …

Stationkeeping Of An L₂ Libration Point Satellite With Θ-D Technique, Ming Xin, S. N. Balakrishnan, Henry J. Pernicka, Michael W. Dancer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A new method for L₂ libration-point orbit stationkeeping is proposed in this paper using continuous thrust. The circular restricted three-body problem with Sun and Earth as the two primaries is considered. The unstable orbit about the L₂ libration-point requires stationkeeping maneuvers to maintain the nominal path. In this study, an approach, called the "θ-D technique," based on optimal control theory gives a closed-form suboptimal feedback solution to solve this nonlinear control problem. In this approach the Hamiltonian-Jacobi-Bellman (HJB) equation is solved approximately by adding some perturbations to the cost function. The controller is designed such that the actual …

Analysis Of Chip-Level Emi Using Near-Field Magnetic Scanning, Xiaopeng Dong, Shaowei Deng, Todd H. Hubing, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

Integrated circuits (ICs) are often a significant source of radiated energy from electronic systems. Well designed ICs maintain good control of the currents that they generate. However, poorly designed ICs can drive high-frequency noise currents onto nominally low-frequency input and output pins. These currents can excite unintentional radiating structures on the printed circuit board, resulting in radiated emissions that are difficult or expensive to control. The paper discusses the use of magnetic near-field scanning techniques to measure the current distribution in IC packages. This technique is applied to common ICs, including a clock driver, a memory module and a field …

Architecting Design Repositories To Support Design Knowledge Storage, Reuse And Design Tool Generation, Matt R. Bohm

Masters Theses

"This collection of works describes the transformation of an existing set of heterogeneous product knowledge into a coherent design repository that supports product information archival, storage, reuse and design tool generation.

Existing product information was analyzed and compared against desired outputs to ascertain what information management structure was needed to produce design resources pertinent to the design process. Methods of incorporating non-conventional functional representations of artifacts are explored, incorporated and standardized along side conventional functional representations. A review of automatic design model generation addresses shortcomings in product representations by comparing standard hand generated design tools to computer-generated design tools. By …

Cost Allocation For Transmission Investment Using Agent-Based Game Theory, Jakapun Mepokee, David Lee Enke, Badrul H. Chowdhury

Engineering Management and Systems Engineering Faculty Research & Creative Works

Due to electrical power restructuring, a dramatic change has been made to the generation and transmission sectors of the power industry. Rules and legislation are continuously changing. To promote more competition, transmission has to be expanded or upgraded to remove congestion and market power. The cost allocation of new investment in transmission has to be recalculated. The socialization methods of the past have been shown to be unfair to some market and network participants. The decentralization of cost allocation must be considered. The proposed paper provides a comparison between traditional cost allocation methods and a new cost allocation method based …

Forecasting Series-Based Stock Price Data Using Direct Reinforcement Learning, H. Li, Cihan H. Dagli, David Lee Enke

Engineering Management and Systems Engineering Faculty Research & Creative Works

A significant amount of work has been done in the area of price series forecasting using soft computing techniques, most of which are based upon supervised learning. Unfortunately, there has been evidence that such models suffer from fundamental drawbacks. Given that the short-term performance of the financial forecasting architecture can be immediately measured, it is possible to integrate reinforcement learning into such applications. In this paper, we present the novel hybrid view for a financial series and critic adaptation stock price forecasting architecture using direct reinforcement. A new utility function called policies-matching ratio is also proposed. The need for the …

Thermal Efficiency Of Steel Melting, Kent D. Peaslee, Semen Naumovich Lekakh, Bradley Randall

Materials Science and Engineering Faculty Research & Creative Works

This paper presents the results of energy consumption measurements at steel foundries using induction and/or electric arc furnace melting. Statistical methods, infrared thermography, and numerical investigations were used for analysis of heat losses. The influence of different melting practices on energy losses was examined. Industrial experiments in isothermal holding of liquid steel in induction furnaces under different power inputs were used for evaluation of the real values of heat losses by radiation from liquid steel and conductivity through lining. Average values and statistical distributions of energy consumptions for melting steel are presented in this article.

Measuring The Robustness Of A Resource Allocation, Shoukat Ali, A. A. Maciejewski, Howard Jay Siegel, Jong-Kook Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Parallel and distributed systems may operate in an environment that undergoes unpredictable changes causing certain system performance features to degrade. Such systems need robustness to guarantee limited degradation despite fluctuations in the behavior of its component parts or environment. This research investigates the robustness of an allocation of resources to tasks in parallel and distributed systems. The main contributions are 1) a mathematical description of a metric for the robustness of a resource allocation with respect to desired system performance features against multiple perturbations in multiple system and environmental conditions, and 2) a procedure for deriving a robustness metric for …

Power Flow And Stability Models For Induction Generators Used In Wind Turbines, Kiran K. Nandigam, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Model initialization of the induction generator for the wind power generation is investigated. Incorrect initialization may lead to numerical instability problems, not to mention erroneous result from dynamic simulation. The machine model is studied from the perspective of slip and reactive power calculation and tested for various cases. The dynamic reactive power calculation in well-know software package is discussed and the deviation of dynamic reactive power from the steady state reactive power is highlighted.

A Unique Fault-Tolerant Design For Flying Capacitor Multilevel Inverter, Xiaomin Kou, Keith Corzine, Yakov L. Familiant

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a unique design for flying capacitor type multilevel inverters with fault-tolerant features. When a single-switch fault per phase occurs, the new design can still provide the same number of converting levels by shorting the fault power semiconductors and reconfiguring the gate controls. The most attractive point of the proposed design is that it can undertake the single-switch fault per phase without sacrificing power converting quality. Future more, if multiple faults occur in different phases and each phase have only one fault switch, the proposed design can still conditionally provide consistent voltage converting levels. This paper will also …

Transmission Line Pulser Construction And Magnetic Field Testing Of Timing Circuits, David James Carter

Masters Theses

"The ability to safely handle unexploded ordinance (UXO) is very important. The goal of the project, presented in this thesis, was to develop a test bed and testing procedures to evaluate the ability of specific UXO timing circuit to be reset through electromagnetic means. Two different platforms for testing were identified at the beginning of the research. One platform is used to expose the circuits to high electric field strengths inside of a TEM cell. The second platform will expose the circuits to high magnetic field strength inside of a Helmholtz coil. Particular specifications for the source of the electric …

Tool Management In Flexible Manufacturing Systems, Ahmet Soylemezoglu

Masters Theses

"In this study, impact of cutting tool life and tool slot size on tool management in Flexible Manufacturing Systems (FMS) is investigated. A conceptual tool management framework, which has been proposed by Buyurgan, Saygin, and Kilic (2003), is modified and implemented in a simulation environment in order to assess its performance. This model, namely LS Model (LS stands for Life and Size), makes decisions by considering both tool life and tool slot size. An alternative tool management model that makes decisions based only on tool life, namely LO Model (LO stands for Life Only), is developed in order to make …

The Dependence Of The Overall Drying Time And Product Quality Of A Lyophilization Process On The Relative Position Of Vials On A Tray With Tray Sides And Without Tray Sides For Different Heat Input Control Policies, Kian Hui Gan

Masters Theses

"The dynamic behavior of the primary and secondary drying stages of the lyophilization process were studied when (a) single vials located at different positions on the tray were individually being dried, and (b) the vials on the tray are arranged in clusters of square and hexagonal arrays and all the vials on the tray are simultaneously being dried. For both cases (a) and (b), fast drying times and relatively more uniform distributions of temperature and concentration of bound water at the end of the secondary drying stage are obtained by heat input control that runs the lyophilization process close to …

Discerning Attributes Which Stimulate Performance In Quality Improvement Teams, Dwan Lamar Prude

Masters Theses

"Total quality management (TQM) can be summed up as people and the way they work. One key element of the philosophies of TQM is the heavy emphasis on utilizing quality improvement teams (QITs) and quality tools to effectively create high performance organizations. Specifically, this investigation asks the following questions: 1) What are the key attributes that contribute to performance in QITs? 2) What is the relationship between team communication and QIT performance? 3) What is the relationship between the number of quality tools utilized in a team and QIT performance? Participants for this study were 101 students from the University …

Chemical Solution Deposition Of Electronic Oxide Films, Robert W. Schwartz, Theodor Schneller, Rainer Waser

Materials Science and Engineering Faculty Research & Creative Works

The chemical solution deposition (CSD) technique as a highly flexible method for the fabrication of electronic oxide thin films is reviewed. Various chemical aspects of different approaches are discussed, including sol-gel, hybrid, and metallo-organic decomposition (MOD) routes, which all have been successfully applied for the deposition of this class of materials. Principles of the selection and properties of the educts, the mechanism of film crystallization, and tailoring of microstructure through manipulation of deposition parameters are reported. the role of thermodynamics on the phase transformation process is also reviewed. Finally, some of the applications for chemical solution-derived thin films currently under …