Digital Commons Network^™

Learning To Learn-Concepts In A First Power Engineering Course, Badrul H. Chowdhury

Electrical and Computer Engineering Faculty Research & Creative Works

Three well-known and widely accepted concepts in educational psychology are revisited. These are "inventory of learning styles," "taxonomy of educational objectives," and "metacognition." Relationships among these concepts are highlighted. Often, a student can develop his (or her) own learning style by the process of metacognition. Ideas are borrowed from these concepts for use in a first-level power systems course. It is beyond a doubt that both cognitive and metacognitive skills are necessary for students to succeed in any course. While a semester-long power systems course leaves little time for critical thinking and passive reflection for students, certain activities may very …

Neural Network Controller For Manipulation Of Micro-Scale Objects, Vijayakumar Janardhan, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement learning-based neural network (RLNN) controller is presented for the manipulation and handling of micro-scale objects in a microelectromechanical system (MEMS). In MEMS, adhesive, surface tension, friction and van der Waals forces are dominant. Moreover, these forces are typically unknown. The RLNN controller consists of an action NN for compensating the unkoown system dynamics, and a critic NN to tune the weights of the action NN. Using the Lyapunov approach, the uniformly ultimate houndedness (UUB) of the closed-loop tracking error and weight estimates are shown by using a novel weight updates. Simulation results are presented to substantiate the …

Optimal Diversity Combining Based On Noisy Channel Estimation, Jingxian Wu, Chengshan Xiao, N. C. Beaulieu

Electrical and Computer Engineering Faculty Research & Creative Works

The performances of coherent diversity receivers with noisy channel estimation are examined. Fading channel gain estimates are modeled as sums of the true fading channel gain values plus independent Gaussian distributed estimation errors. The optimal diversity receiver for coherent reception with noisy channel state information and independent and identically distributed fading channels is derived. Exact expressions for the average error probability of optimal diversity MPSK with noisy channel estimation are derived for Rayleigh and Ricean fading channels; closed-form expressions are obtained for some special cases. Some interesting observations regarding practical diversity receiver design for higher-order modulation formats are drawn.

Comprehensive Evaluation Of Animated Instructional Software For Mechanics Of Materials, Timothy A. Philpot, Richard H. Hall

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

During the past three years, the Basic Engineering Department at the University of Missouri--Rolla has been developing a second-generation suite of instructional software called MecMovies for the mechanics of materials course. In the Fall 2003 semester, MecMovies was integrated into assignments throughout the entire semester for one of the six UMR mechanics of materials sections. This paper presents a comparison of student performance in the experimental section with student performance in five control sections along with discussion of student qualitative ratings and comments.

Ultraviolet Photonic Crystal Laser, Alexey Yamilov, Hui Cao, Robert P. H. Chang, Xiaohua Wu, Xang Liu, Shuyou Li, Vinayak P. Dravid

Physics Faculty Research & Creative Works

We fabricated two-dimensional photonic crystal structures in zinc oxide films with focused-ion-beam etching. Lasing is realized in the near-ultraviolet frequency at room temperature under optical pumping. From the measurement of lasing frequency and spatial profile of the lasing modes, as well as the photonic band structure calculation, we conclude that lasing occurs in the strongly localized defect modes near the edges of photonic band gap. These defect modes originate from the structure disorder unintentionally introduced during the fabrication process. ©2004 American Institute of Physics

Variational Considerations In The Study Of Carrier Transport In Organic Crystals, V. M. Kenkre, Paul Ernest Parris

Physics Faculty Research & Creative Works

A variational approach is used to investigate consequences of electron-phonon interactions between a charge carrier and multiple (specifically two) phonon branches. Phase diagrams are obtained and the nature of the transition from undressed to dressed phases of the carrier is studied with their help. No sharp transition between singly dressed and doubly dressed phases occurs. The effective carrier bandwidth, reduced by strong coupling to the high-frequency branch is found to be stable with respect to small to intermediate values of additional coupling to the low-frequency branch. This finding lends support to transport calculations based on the idea that carriers in …

An Integral Form Of The Variational Nodal Method, M. A. Smith, G. Palmiotti, E. E. Lewis, Nicholas Tsoulfanidis

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

An integral form of the variational nodal method is formulated, implemented, and tested. the method combines an integral transport treatment of the even-parity flux within the spatial node with an odd-parity spherical harmonics expansion of the Lagrange multipliers at the node interfaces. the response matrices that result from this formulation are compatible with those in the VARIANT code at Argonne National Laboratory. Spatial discretization within each node allows for accurate treatment of homogeneous or heterogeneous node geometries. the integral method is implemented in Cartesian x-y geometry and applied to three benchmark problems. the method's accuracy is compared to that of …

Adaptive Force-Balancing Control Of Mems Gyroscope With Actuator Limits, Mohammed Hameed, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

This work presents an adaptive force-balancing control (AFBC) scheme with actuator limits for a MEMS Z-axis gyroscope. The purpose of the adaptive force-balancing control is to identify major fabrication imperfections so that they are properly compensated unlike the case of conventional force-balancing controlled gyroscope. The proposed AFBC scheme controls the vibratory modes of the proof mass while ensuring that the control input satisfies the magnitude constraints and the performance of the gyroscope is enhanced in the presence of fabrication uncertainties. Consequently, commonly reported problems of MEMS gyroscope such as quadrature compensation, drive and sense axes frequency tuning are not needed …

An Engineering Primer For Outreach To K-4 Education, Theresa M. Swift, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

Student motivation for and proficiency in science and mathematics begin in the early grades. Level-appropriate resources and professional outreach activities are as beneficial for teachers and students at elementary levels as for higher levels. Engineering applications can be effective vehicles for giving students hands-on exposure to technical concepts and for showing students how these concepts relate to everyday life. To improve the technical literacy of society and to promote STEM-related careers, engineers should be engaged in active outreach. However, engineers who seek these types of projects have some learning to do themselves. They must understand the unique elementary education environment …

Boost Integrated Push-Pull Rectifier With Power Factor Correction And Output Voltage Regulation Using A New Digital Control Technique, Zhong Nie, Mehdi Ferdowsi, Ali Emadi

Electrical and Computer Engineering Faculty Research & Creative Works

An integrated converter is a synthesized converter based on the overall system integration, which is simplified by the system objective and can implement the system functions similar to the discrete converters. An integrated converter consists of converter sets; each converter set has a special function defined by the designer. A family of DC/DC Boost based integrated rectifiers with two active switches can be derived by the integration concept. In this paper, Boost + Push-Pull integrated converter is introduced and derived. To regulate the output voltage and shape the input current, a new simple digital control method is applied. In contrast …

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

Electrical and Computer Engineering Faculty Research & Creative Works

Electrostatic discharge (ESD) generators are used for testing the robustness of electronics toward ESD. Most generators are built in accordance with the IEC 61000-4-2 specifications. Using only a few parameters, this standard specifies the peak current, the rise time and the falling edge. Lacking a transient field specification, test results vary depending on which generator is used, even if the currents are quite similar. Such a specification is needed to improve the test repeatability. As for the current, the specification should be based on a reference human metal ESD event. While keeping the presently set peak current and rise time …

Decentralized Neural Network Control Of A Class Of Large-Scale Systems With Unknown Interconnection, Wenxin Liu, Jagannathan Sarangapani, Donald C. Wunsch, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

A novel decentralized neural network (DNN) controller is proposed for a class of large-scale nonlinear systems with unknown interconnections. The objective is to design a DNN for a class of large-scale systems which do not satisfy the matching condition requirement. The NNs are used to approximate the unknown subsystem dynamics and the interconnections. The DNN is designed using the back stepping methodology with only local signals for feedback. All of the signals in the closed loop (system states and weights estimation errors) are guaranteed to be uniformly ultimately bounded and eventually converge to a compact set.

Space-Time Fading Correlation Functions Of A 3-D Mimo Channel Model, Sang-Yick Leong, Y. Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

Space-time correlation functions between the links of MIMO Rayleigh fading channels are derived using a new three-dimensional (3-D) cylinder scattering model. Closed form, mathematically tractable formulas are obtained for the space-time correlation functions for general MIMO systems where the base station and mobile station antennas may be arranged in 3-D space. It is shown that the correlation functions computed by the 3-D cylinder model are of significant difference than those of the conventional 2-D Clarke''s isotropic scattering model for vertically placed antennas. The general formulas of the correlation functions includes the 2-D Clarke''s model and the 3-D SIMO, MISO models …

Temperature Considerations In Solar Arrays, Steve Eugene Watkins, Min-Jung Wu, E. J. Timpson

Electrical and Computer Engineering Faculty Research & Creative Works

Temperature is an important consideration in the operation of photovoltaic (PV) arrays. In particular, daily and seasonal temperature variations are a limitation on the application of solar power to homes. At lower temperatures, PV systems produce more power. For higher temperatures, optimum operation requires modification of electrical load and removal of excess heat. Several technologies and approaches are available. To pursue this system optimization, PV cells were investigated at different temperatures. These investigations are compared with simulated theoretical results to draw more specific conclusions that can be applied to a solar house. A temperature reduction of 60⁰C improved the power …

Adaptive Load Frequency Control Of Nigerian Hydrothermal System Using Unsupervised And Supervised Learning Neural Networks, Ganesh K. Venayagamoorthy, U. O. Aliyu, S. Y. Musa

Electrical and Computer Engineering Faculty Research & Creative Works

This work presents a novel load frequency control design approach for a two-area power system that relies on unsupervised and supervised learning neural network structure. Central to this approach is the prediction of the load disturbance of each area at every minute interval that is uniquely assigned to a cluster via unsupervised learning process. The controller feedback gains corresponding to each cluster center are determined using modal control technique. Thereafter, supervised learning neural network (SLNN) is employed to learn the mapping between each cluster center and its feedback gains. A real time load disturbance in either or both areas activates …

Educational Change Process: A Case Study Of A Rural School District's Reading Reform, Barbara M. Havel Bohach

Dissertations and Theses @ UNI

Beginning reading instruction is the subject of much debate in educational fields as well as in the political arena. The product of such debates is often a push to reform reading programs and teachers are targeted as the ones to carry out these reforms. If reading educators have been actively involved in a reading change process, what are their concerns about change and the influence of mandated legislation?

The purpose of this qualitative research study was to examine how teachers and administrators initiated and implemented a balanced reading innovation. It also investigated how the Concerns-Based Adoption Model identified teachers' concerns …

Building A Comprehensive Energy Model For Off-Highway Vehicles With Emphasis On Vehicle Thermal Control Systems, Ayhan Zora

Dissertations and Theses @ UNI

Utilizing machine and thermal system simulations (vehicle energy models) can be very helpful for vehicle manufacturing companies to develop a machine with acceptable component temperatures, less heat loads to the vehicle cooling systems, and reduced emissions that will also reduce overall product development cycle.

Energy models of vehicles were developed mostly in the automotive industry, and most of these studies were based on partial energy models.

The aim of this research study was to create a comprehensive energy model for agricultural machinery, which will be a basis for future work on similar products. A tractor model from a Midwest off-road …

Application Of Case Study Methodology In The Context Of Undergraduate Critical Care Nursing Education, James A. Hauschildt

Dissertations and Theses @ UNI

This study represented an initial effort to investigate how a case study methodology could be used in the context of critical care nursing education. The study hoped to improve students' content specific knowledge of critical care nursing and facilitate critical thinking processes vital to clinical decision making. The study describes the transformation of a critical care-nursing course from a traditional lecture-based approach to a case study approach.

The traditional approach addressed the content through abundant teacher centered lecture, but did not require students to actively engage in discourse or apply critical thinking skills to real nursing problems. The case study …

Modeling And Measuring The Dispersion Of Odors From Hog Confinements, François Béra

Dissertations and Theses @ UNI

A comparison was made between predicted and measured odor concentration downwind of two hog finishing confinements. Two Gaussian dispersion models, STINKBAK and AERMOD, were used. The experimental cases examined odor emanating from a mechanically-ventilated facility and a curtain-sided facility during summer 2003. A field olfactometer was used to measure odor concentration. The odor concentrations served as input to STINKBAK, which then estimated the odor emission rate from the confinement. AERMOD used this emission rate and other meteorological data to predict the peak concentration of odor around the confinement over the sampling hour.

The calculated odor emission rates are slightly higher …

Mapping Wetlands And Potential Wetland Restoration Areas In Black Hawk County, Iowa Using Object-Oriented Classification And A Gis-Based Model, James Harken

Dissertations and Theses @ UNI

Wetlands are transitional lands between terrestrial and aquatic systems that provide many benefits, including: floodwater retention, non-point pollution treatment, wildlife habitat, and soil-erosion control. Wetlands in Iowa have decreased over 95% in the last 200 years. Therefore, there is a need to map and monitor these resources, as well as to determine potential sites for wetland restoration. In Black Hawk County, wetland maps are outdated, and ground surveys have proved to be too time-consuming and expensive. Traditional pixel-based automated classifiers of remotely-sensed imagery have also proven to be inaccurate in classifying wetlands because of spectral confusion. This study tests multispectral …

Optimisation Of John The Ripper In A Clustered Linux Environment, Christian Frichot

Theses : Honours

To aid system administrators in enforcing strict password policies, the use of password cracking tools such as Cisilia (C.I.S.I.ar, 2003) and John the Ripper (Solar Designer, 2002), have been employed as software utilities to look for "weak" passwords. John the Ripper (JtR) attempts to crack the passwords by using a dictionary, brute-force or "other" mode of attack. The computational intensity of cracking passwords has led to the utilisation of parallel-processing environments to increase the speed of the password-cracking task. Parallel-processing environments can consist of either single systems with multiple processors, or a collection of separate computers working together as a …

Natural Regeneration Of Native Vegetation On Abandoned Agricultural Land In The Fitzgerald Biosphere, Nerilee Boshammer

Theses : Honours

Much of the natural landscape in the south-west of Western Australia has been severely modified as a result of past and current agricultural activity. One of the most conspicuous changes has been the large scale clearing of native vegetation, The evidence of the negative impacts of this vegetation removal on the natural environment is now extensive, particularly in the south-west region of the State. In order to prevent further degradation of the landscape of the south-west and subsequent loss of endemic species, strategic revegetation within the agricultural landscape is required. Native vegetation corridors can be established, linking areas of remnant …

Financial Statement Analysis, Steelman Library

Syllabus Repository

No abstract provided.

Predicting Dynamics Of Aggregate Loafing Behavior In Glaucous-Winged Gulls (Larus Glaucescens) At A Washington Colony, Shandelle M. Henson, James L. Hayward, Christina M. Burden, Clara J. Logan, Joseph G. Galusha

Faculty Publications

Seabirds move throughout the day in changing, patchy environments as they engage in various behaviors. We studied the diurnal abundance dynamics of Glaucous-winged Gulls (Larus glaucescens) in a habitat patch dedicated to loafing in the Strait of Juan de Fuca, Washington. We constructed three differential equation models as alternative hypotheses and then used model selection techniques to choose the one that most accurately described the system. We validated the model on an independent data set, made a priori model predictions, and conducted a field test of the predictions. Clear dynamic patterns emerged in the abundance of loafing gulls, even though …

A Physics-Based Analytical Model Of An Algan/Gan High Electron Mobility Transistor, Jonathan Sippel

Theses

Popular semiconductors currently being used for RF applications include GaAs and InP. The operating frequencies for HEMTs built with these semiconductors covers the range from 800 MHz to 100 GHz. Although high-speed operation is attainable using GaAs or InP, product performance is limited when considering high-power applications, where a high breakdown field and thermal conductivity is needed. Proposed about fifteen years ago as a solution to this problem, GaN has emerged as a viable candidate to challenge, and perhaps overtake, GaAs and InP as the dominant semiconductor in RF products, particularly power amplifiers. This is due to its high breakdown …

Experimental Study Of Flow Patterns, Heat Transfer, Pressure Drop And Gravitational Orientation During Flow Boiling In Minichannels, Prabhu Balasubramanian

Theses

Microchannels and Minichannels are being used in electronic cooling, fuel cells, automotive heat exchangers, micro refrigeration systems. They are also being considered for high heat flux applications under microgravity environment in space missions. Research laboratories and industries throughout the world are trying to explore and tap the potential uses of these small diameter channels in various products and applications. Before stepping in to any of the product design phase, fundamental issues related to their performance have to be studied and resolved. This thesis work focuses on resolving some of these fundamental issues related to flow boiling in small diameter channels …

Analytical And Numerical Modeling To Address Signal Integrity Issues In Mixed Signal Applications, Jeffrey D. Mcfiggins

Theses

Signal integrity issues are a major concern in highly integrated and compact mixed signal IC's. This work presents a numerical and analytical method for analyzing and assessing signal integrity issues relating to discontinuities, interconnects, and irregularly shaped power planes through the development of two independent methods. To address the coupling issue the finite difference time domain (FDTD) technique has been used, which is an accurate and robust algorithm capable of analyzing an arbitrary geometry in both the frequency and time domains. The analysis of signal integrity issues is carried out using examples such as transmission lines placed in close proximity, …

High-Q2 Neutral Current Cross Sections In E+ P Deep Inelastic Scattering At √S = 318 Gev, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli

Faculty Publications

Cross sections for e+ p neutral current deep inelastic scattering have been measured at a center-of-mass energy of √s = 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 63.2 pb -1. The double-differential cross section, d2σ/ dxdQ2, is presented for 200 GeV2 < Q2 < 30 000 GeV2 and for 0.005 < x < 0.65. The single-differential cross sections dσ/dQ2, dσ/dx and dσ/dy are presented for Q2 > 200 GeV2. The effect of Z-boson-exchange is seen in dσ/dx measured for Q2 > 10 000 GeV2. The data presented here were combined with ZEUS e+ p neutral current data taken at √s = 300 GeV and the structure function F2em was extracted. All results agree well with the predictions of the Standard Model.

Observation Of KS0KS0 Resonances In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli, A. Zichichi

Faculty Publications

Inclusive Ks0Ks0 production in deep inelastic ep scattering at HERA has been studied with the ZEUS detector using an integrated luminosity of 120 pb-1. Two states are observed at masses of 1537-8-9 MeV and 1726 ± 7 MeV, as well as an enhancement around 1300 MeV. The state at 1537 MeV is consistent with the well established f′2(1525). The state at 1726 MeV may be the glueball candidate f0(1710). However, it's width of 38 -14-20 MeV is narrower than 125 ± 10 MeV observed by previous experiments for the f0(1710). © 2003 Elsevier B.V. All rights reserved.

Anatomy Of A Chaotic Attractor: Subtle Model-Predicted Patterns Revealed In Population Data, Aaron A. King, R. F. Costantino, J. M. Cushing, Shandelle M. Henson, Robert A. Desharnais, Brian Dennis

Faculty Publications

Mathematically, chaotic dynamics are not devoid of order but display episodes of near-cyclic temporal patterns. This is illustrated, in interesting ways, in the case of chaotic biological populations. Despite the individual nature of organisms and the noisy nature of biological time series, subtle temporal patterns have been detected. By using data drawn from chaotic insect populations, we show quantitatively that chaos manifests itself as a tapestry of identifiable and predictable patterns woven together by stochasticity. We show too that the mixture of patterns an experimentalist can expect to see depends on the scale of the system under study.