Digital Commons Network^™

Neural Network Control Of Robot Formations Using Rise Feedback, Jagannathan Sarangapani, Travis Alan Dierks

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a combined kinematic/torque control law is developed for leader-follower based formation control using backstepping in order to accommodate the dynamics of the robots and the formation in contrast with kinematic-based formation controllers that are widely reported in the literature. A neural network (NN) is introduced along with robust integral of the sign of the error (RISE) feedback to approximate the dynamics of the follower as well as its leader using online weight tuning. It is shown using Lyapunov theory that the errors for the entire formation are asymptotically stable and the NN weights are bounded as opposed …

Irradiation And Metal-Containing Conjugated-Polymer Nanocomposites, Frank D. Blum, Zhe-Fei Li, Sunil K. Pillalamarri, Massimo F. Bertino

Chemistry Faculty Research & Creative Works

In recent years, there has been considerable interest in inorganic/organic hybrid materials that combine the desirable properties of both classes. These composite materials may find significant application in a variety of applications such as sensors, memory and energy conversion, to name just a few. In our laboratories, we have recently made a series of studies on the production of polymer nanofibers and their composites with nanometals. Much of this work has focused on the production of polyaniline (PANI) nanofibers that have been made from one-pot syntheses in aqueous solutions where the polymerization was influenced by -radiation1 or UV-radiation.2 in the …

Online Reinforcement Learning Control Of Unknown Nonaffine Nonlinear Discrete Time Systems, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel neural network (NN) based online reinforcement learning controller is designed for nonaffine nonlinear discrete-time systems with bounded disturbances. The nonaffine systems are represented by nonlinear auto regressive moving average with exogenous input (NARMAX) model with unknown nonlinear functions. An equivalent affine-like representation for the tracking error dynamics is developed first from the original nonaffine system. Subsequently, a reinforcement learning-based neural network (NN) controller is proposed for the affine-like nonlinear error dynamic system. The control scheme consists of two NNs. One NN is designated as the critic, which approximates a predefined long-term cost function, whereas an …

Optimal Neuro-Fuzzy External Controller For A Statcom In The 12-Bus Benchmark Power System, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

An optimal neuro-fuzzy external controller is designed in this paper for a static compensator (STATCOM) in the 12-bus benchmark power system. The controller provides an auxiliary reference signal for the STATCOM in such a way that it improves the damping of the rotor speed deviations of its neighboring generators. A Mamdani fuzzy rule base constitutes the core of the controller. A heuristic dynamic programming-based approach is used to further train the controller and enable it to provide nonlinear optimal control at different operating conditions of the power system. Simulation results are provided that indicate the proposed neuro-fuzzy external controller is …

Optimal Wide Area Controller And State Predictor For A Power System, Salman Mohagheghi, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

An optimal wide area controller is designed in this paper for a 12-bus power system together with a Static Compensator (STATCOM). The controller provides auxiliary reference signals for the automatic voltage regulators (AVR) of the generators as well as the line voltage controller of the STATCOM in such a way that it improves the damping of the rotor speed deviations of the synchronous machines. Adaptive critic designs theory is used to implement the controller and enable it to provide nonlinear optimal control over the infinite horizon time of the problem and at different operating conditions of the power system. Simulation …

Dynamic Simulations Of Cascading Failures, Hong Tao Ma, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Steady state analysis cannot provide the details of how system evolves in cascading failure. Dynamic response of generator plays an important role in power system operation and blackout events. In this paper, classical generator and detail generator models are integrated into system model for cascading dynamic simulations.. The cascading scenarios are compared using both steady state and dynamic simulations. Classical models are simpler; however, the detailed generator model is more accurate. Generator performance of speed deviation and angle deviations as well as the bus voltage profile are investigated for various scenarios. The IEEE 118-bus, 20-generator test case is used as …

Frequency-Domain Channel Estimation And Equalization For Single Carrier Underwater Acoustic Communications, Y. Rosa Zheng, Chengshan Xiao, T. C. Yang, Wen-Bin Yang

Electrical and Computer Engineering Faculty Research & Creative Works

A new frequency-domain channel estimation and equalization (FDE) scheme is proposed for single carrier (SC) underwater acoustic communications. The proposed SC-FDE employs a small training signal block for initial channel estimation in the frequency domain and converts the estimated transfer function to a desired DFT (discrete Fourier transform) size for channel equalization of the data blocks. The frequency domain equalizer is designed using the linear minimum mean square error criterion. A new phase coherent detection scheme is also proposed and deployed to combat the phase drift due to the instantaneous Doppler in the underwater channels. The channel transfer functions and …

Evaluation Of Time Independent Rheological Models Applicable To Fresh Self-Compacting Concrete, Dimitri Feys, Ronny Verhoeven, Geert De Schutter

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-Compacting Concrete is a New Type of Concrete Which is More Liquid Compared to Traditional Concrete and Which Does Not Need Any Form of External Compaction. as a Result, This Type of Concrete is Suitable for a New Placing Technique: Pumping SCC from the Bottom in the Formwork and Letting It Rise in the Formwork Due to the Applied Pressure. in Order to Understand the Phenomena Occurring during Pumping Operations, the Rheological Properties of SCC Must Be Investigated and Controlled. Tests Have Been Performed with Two Different Rheometers, Which Are Described in This Paper. for the Tattersall MIk-II Rheometer, a …

Implementation Of A Converter In Sequence Domain To Counter Voltage Imbalances, Murali M. Baggu, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

This paper demonstrates the basic problem of the conventional d-axis and q-axis control applied to a voltage source converter (VSC) during a system imbalance. The specific imbalances studied are a balanced fault and an unbalanced fault at the terminals of the converter. The dc link voltage of the VSC is disturbed during the unbalanced fault due to negative sequence components in the system. The sequence characteristics of the system during an imbalance are further analyzed. A novel controller in the sequence domain is proposed. The positive sequence components of the control are implemented in the positive synchronous reference frame and …

Mobile Speed Estimation For Broadband Wireless Communications, Y. Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a new algorithm is proposed to estimate mobile speed for broadband wireless communications, which often encounter large number of fading channel taps causing severe intersymbol interference. Theoretical analysis is first derived and practical algorithm is proposed based on the analytical results. The algorithm employs a modified auto-covariance of received signal power to estimate the speed of mobiles. The algorithm is based on the received signals which contain unknown transmitted data, unknown frequency selective multipaths possibly including line-of-sight (LOS) component, and random receiver noise. The algorithm works well for frequency selective Rayleigh and Rician channels. The algorithm is …

Near Optimal Neural Network-Based Output Feedback Control Of Affine Nonlinear Discrete-Time Systems, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel online reinforcement learning neural network (NN)-based optimal output feedback controller, referred to as adaptive critic controller, is proposed for affine nonlinear discrete-time systems, to deliver a desired tracking performance. The adaptive critic design consist of three entities, an observer to estimate the system states, an action network that produces optimal control input and a critic that evaluates the performance of the action network. The critic is termed adaptive as it adapts itself to output the optimal cost-to-go function which is based on the standard Bellman equation. By using the Lyapunov approach, the uniformly ultimate boundedness …

Neural Network Controller Development And Implementation For Spark Ignition Engines With High Egr Levels, Jonathan B. Vance, Atmika Singh, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

Past research has shown substantial reductions in the oxides of nitrogen (NOx) concentrations by using 10% -25% exhaust gas recirculation (EGR) in spark ignition (SI) engines (see Dudek and Sain, 1989). However, under high EGR levels, the engine exhibits strong cyclic dispersion in heat release which may lead to instability and unsatisfactory performance preventing commercial engines to operate with high EGR levels. A neural network (NN)-based output feedback controller is developed to reduce cyclic variation in the heat release under high levels of EGR even when the engine dynamics are unknown by using fuel as the control input. A separate …

On The Error Performance Of Wireless Systems With Frequency Selective Fading And Receiver Timing Phase Offset, Jingxian Wu, Y. Rosa Zheng, Khaled Ben Letaief, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Online Reinforcement Learning Neural Network Controller Design For Nanomanipulation, Qinmin Yang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a novel reinforcement learning neural network (NN)-based controller, referred to adaptive critic controller, is proposed for affine nonlinear discrete-time systems with applications to nanomanipulation. In the online NN reinforcement learning method, one NN is designated as the critic NN, which approximates the long-term cost function by assuming that the states of the nonlinear systems is available for measurement. An action NN is employed to derive an optimal control signal to track a desired system trajectory while minimizing the cost function. Online updating weight tuning schemes for these two NNs are also derived. By using the Lyapunov approach, …

Visual Traffic Movement Counts At Intersection For Origin-Destination (O-D) Trip Table Estimation, S. Lee, Hojong Baik, J. Park

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Origin-destination (O-D) trip table is necessary information for transportation planning and traffic impact study. However, current O-D estimations rely on estimated directional traffic counts at intersections, which obviously diminish reliability in the table. A video-based vehicle tracking system that utilizes wide view-angle lenses has been studied [26] to provide accurate direction traffic counts. The system expands the area covered by a single camera and uses a particle filtering method to handle environmental changes as well as geometric distortion caused by those lenses. This paper shows tracking capability of the system and also shows how to incorporate the directional traffic counts …

Heat Transfer Coefficients In A High-Pressure Bubble Column, Chengtian Wu, Muthanna H. Al-Dahhan, Anand Prakash

Chemical and Biochemical Engineering Faculty Research & Creative Works

Time-Averaged Local Heat Transfer Coefficients Were Studied in a 0.16 M Inner Diameter High-Pressure Air-Water Bubble Column. the Effects of the Superficial Gas Velocity (Up to 0.30 M/s), Pressure (Up to 10 Bar), Probe Position, and Probe Orientation Were Investigated. the Heat Transfer Coefficients Increased with Superficial Gas Velocity, and the Values in the Center of the Column Were 9-16% Greater Than Those Near the Wall Region under Atmospheric Pressure (1 Bar). with the Increase in Pressure, the Heat Transfer Coefficients Decreased Due to Combined Effects of Bubble Size Decreasing, Gas Holdup Increasing, and Bubble Number Increasing. the Heat Transfer …

Gas-Liquid Mass Transfer In A High Pressure Bubble Column Reactor With Different Sparger Designs, Lu Han, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Gas-Liquid Mass Transfer in a 0.162 M High-Pressure Stainless-Steel Bubble Column Was Investigated using Three Different Gas Sparger Designs. an Oxygen-Enriched-Air Dynamic Method and an Optical Oxygen Probe Technique Were Implemented to Measure K1 a Values in the Bubble Column Reactor. using the Interfacial Area (A) Values Measured by a Four-Point Optical Probe Technique at Similar Conditions (Xue, 2004), the K1 Values Were Estimated. Axial Dispersion Model (ADM) and Continuous Stirred Tank Reactor (CSTR) Model Were Used to Calculate K1 a as a Fitted Parameter with the Measured Data. the ADM Gave Better Fits to the Experimental Data Than …

Adaptive Power Control Protocol With Hardware Implementation For Wireless Sensor And Rfid Reader Networks, Kainan Cha, Jagannathan Sarangapani, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

The development and deployment of radio frequency identification (RFID) systems render a novel distributed sensor network which enhances visibility into manufacturing processes. In RFID systems, the detection range and read rates will suffer from interference among high-power reading devices. This problem grows severely and degrades system performance in dense RFID networks. Consequently, medium access protocols (MAC) protocols are needed for such networks to assess and provide access to the channel so that tags can be read accurately. In this paper, we investigate a suite of feasible power control schemes to ensure overall coverage area of the system while maintaining a …

Comparison Of Nonuniform Optimal Quantizer Designs For Speech Coding With Adaptive Critics And Particle Swarm, Ganesh K. Venayagamoorthy, Wenwei Zha

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a companding nonuniform optimal scalar quantizer for speech coding. The quantizer is designed using two neural networks to perform the nonlinear transformation. These neural networks are used in the front and back ends of a uniform quantizer. Two approaches are presented in this paper namely adaptive critic designs and particle swarm optimization, aiming to maximize the signal-to-noise ratio. The comparison of these optimal quantizer designs over a bit-rate range of 3-6 is presented. The perceptual quality of the coding is evaluated by the International Telecommunication Union's Perceptual Evaluation of Speech Quality standard

Lawrence Baron. Projecting The Holocaust Into The Present: The Changing Focus Of Contemporary Holocaust Cinema (Book Review), Kathrin M. Bower

Languages, Literatures, and Cultures Faculty Publications

Projecting the Holocaust is a valuable addition to extant scholarship on Holocaust cinema and offers a refreshingly inclusive and positive take on how feature films contribute to our understanding of history. In contrast to other surveys of Holocaust cinema, Baron includes films that focus on stories of perpetrators, non-Jewish victims, the experiences of the second generation, and neo-Nazi groups. This inclusivity is also evident in Baron's position that the Holocaust is not the property of specific countries or peoples and that its representation speaks to universal concerns about human civilization as well as to particular questions about national identities.

Design Of An Fpga Logic Element For Implementing Asynchronous Null Convention Logic Circuits, Scott C. Smith

Electrical and Computer Engineering Faculty Research & Creative Works

Two versions of a reconfigurable logic element are developed for use in constructing afield-programmable gate array NULL convention logic (NCL) field-programmable gate array (FPGA): one with extra embedded registration capability, which requires additional area, and one without. Both versions can be configured as any of the 27 fundamental NCL gates, including resettable and inverting variations, and both can utilize embedded registration for gates with three or fewer inputs; however, only the version with the additional embedded registration capability can utilize embedded registration with four-input gates. These two approaches are compared with each other and with an existing approach, showing that …

Doppler Spread Estimation For Broadband Wireless Ofdm Systems, Jun Tao, Jingxian Wu, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, we present a new Doppler spread estimation algorithm for broadband wireless orthogonal frequency division multiplexing (OFDM) systems with time-varying and frequency-selective Rayleigh fading. The algorithm is developed by analyzing the statistical properties of the power of received signals in the time domain, thus it excludes the influence of inter- carrier interference introduced by channel variation within one OFDM symbol. The operation of the algorithm doesn't require the knowledge of fading coefficients, transmitted data symbols, or signal-to-noise ratio (SNR). It works well under time-selective and frequency-selective Rayleigh fading channel with SNR as low as 0 dB. Moreover, unlike …

Route Aware Predictive Congestion Control Protocol For Wireless Sensor Networks, Carl Larsen, Maciej Jan Zawodniok, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

Congestion in wireless sensor networks (WSN) may lead to packet losses or delayed delivery of important information rendering the WSN-based monitoring or control system useless. In this paper a routing-aware predictive congestion control (RPCC) yet decentralized scheme for WSN is presented that uses a combination of a hop by hop congestion control mechanism to maintain desired level of buffer occupancy, and a dynamic routing scheme that works in concert with the congestion control mechanism to forward the packets through less congested nodes. The proposed adaptive approach restricts the incoming traffic thus preventing buffer overflow while maintaining the rate through an …

Averaging Of The Electron Effective Mass In Multicomponent Transparent Conducting Oxides, Julia E. Medvedeva

Physics Faculty Research & Creative Works

We find that layered materials composed of various oxides of cations with s² electronic configuration, XY₂O₄, X = in or Sc, Y = Ga, Zn, Al, Cd and/or Mg, exhibit isotropic electron effective mass which can be obtained via averaging over those of the corresponding single-cation oxide constituents. This effect is due to a hybrid nature of the conduction band formed from the s-states of all cations and the oxygen p-states. Moreover, the observed insensitivity of the electron effective mass to the oxygen coordination and to the distortions in the cation-oxygen chains suggests that a …

Quantum-Theory Based Event Generator For The Analysis Of Kinematically Complete Experiments, M. Dürr, B. Najjari, Michael Schulz, A. Dorn, R. Moshammer, J. Ullrich

Physics Faculty Research & Creative Works

The 'reaction microscope', an electron-ion coincidence momentum imaging spectrometer, represents a unique technique to measure multiply differential ionization cross sections for ionic projectiles. Observed discrepancies with theory for singly ionizing collision of 3.6 MeV/u Au53+ and 100 MeV/u C6+ ions severely challenge theoretical models. We present a method based on event-generators, which allows to consistently incorporate instrumental effects into theory. The result of the convolution procedure suggests, that the observed discrepancies are not a result of the experimental resolution, but are of true physical nature.

Evidence Of Dynamical Spin Shielding In Ce From Spin-Resolved Photoelectron Spectroscopy, James G. Tobin, S. W. Yu, Takashi Komesu, B. W. Chung, Simon A. Morton, George Daniel Waddill

Physics Faculty Research & Creative Works

Using Fano effect measurements upon polycrystalline Ce, we have observed a phase reversal between the spectral structure at the Fermi edge and the other 4f derived feature near a binding energy of 2 eV. The Fano effect is the observation of spin polarized photoelectron emission from nonmagnetic materials, under chirally selective excitation, such as circularly polarized photons. The observation of phase reversal between the two peaks is a direct experimental proof of Kondo shielding in Ce, confirming the predictions of Gunnarsson and Shoenhammer, albeit with a small modification.

What Happens When Veteran And Beginner Teachers' Life Histories Intersect With High-Stakes Testing And What Does It Mean For Learners And Teaching Practice: The Making Of A Culture Of Fear, Shelly L. Counsell

Dissertations and Theses @ UNI

This qualitative study explored the phenomenon of what happened as Florida's high-stakes accountability system intersected with a beginning and veteran teachers' life histories and different stocks of lifeworldly knowledge at demographically different lifeworld communities. Habermas' (1987) theory of communicative action was used as the theoretical framework to explore what the teachers' responses meant for learners and teaching practice. The research purpose of this study (emphasizing an interpretive approach) sought to gain insights and understandings regarding the phenomenon specifically. The practical purpose (according to critical theory) was to then use the insights gained (enlightenment) in order to contemplate the kinds of …

A Study Of Elementary Instructors' Teaching Of Forearm Passing As A Part Of Volleyball Instruction, Tsui-Feng Tiffany Yeh

Dissertations and Theses @ UNI

The purpose of this study was to investigate the teaching of forearm passing as a key component of volleyball game performance. More specifically, this study investigated teachers' content knowledge and teaching knowledge (pedagogical content knowledge) related to forearm passing as described by the teachers and manifested in teaching practices in the teaching environment.

Six elementary physical education instructors participated in this study. Several methods were used for gathering different information about forearm passing research including systematic observation, videotaping, field notes, and formal and informal interviews.

The findings revealed that (a) teachers' teaching philosophy significantly influenced their teaching and designing volleyball …

The Effects Of Facial Attractiveness, Weight, And Immediacy On Social Influence: A Test Of Dynamic Social Impact, Melinda Bullock

Dissertations and Theses @ UNI

Social impact theory (Latane, 1981) explains social influence as a multiplicative function of strength, immediacy, and number. Dynamic social impact theory (Latane, 1996a) states that four phenomena occur as a result of social influence: a) clustering (those living close together have similar attitudes), b) correlation (once unrelated attitudes become associated), c) consolidation (reduction in overall attitude variance), and d) continuing diversity (in spite of social influence attitudes diversity persists). This study used these two theories to examine how facial attractiveness, weight, and immediacy affect social influence. It. was expected that clustering, correlation, and consolidation would occur to a greater extent …

Performance Analysis Of Wireless Systems With Doubly Selective Rayleigh Fading, Jingxian Wu, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Theoretical error performances of wireless communication systems suffering from both doubly selective (time varying and frequency selective) Rayleigh fading and sampler timing offset are analyzed in this paper. Single-input-single-output systems with doubly selective fading channels are equivalently represented as discrete-time single-input-multiple-output (SIMO) systems with correlated frequency-flat fading channels, with the correlation information being determined by the combined effects of sampler timing phase, maximum Doppler spread, and power delay profile of the physical fading. Based on the equivalent SIMO system representation, closed-form error-probability expressions are derived as tight lower bounds for linearly modulated systems with fractionally spaced equalizers. The information on …