Engineering Commons^™

A Product Architecture-Based Conceptual Dfa Technique, Robert B. Stone, Daniel A. Mcadams, Varghese J. Kayyalethekkel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A conceptual design for assembly (DFA) method is introduced in this paper. The method incorporates DFA analysis into the conceptual design phase. Current DFA methods, essentially all of which are post-design DFA analyses, are reviewed with emphasis on the popular Boothroyd and Dewhurst method. The product architecture-based conceptual DFA method developed and presented in this article uses two relatively new concepts: the functional basis and the method of module heuristics. The functional basis is used to derive a functional model of a product in a standard language and the module heuristics are applied to the functional model to identify a …

Definition Of A Robustness Metric For 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 of this paper are (1) a mathematical description of a metric for the robustness of a resource allocation with respect to desired system performance features against perturbations in system and environmental conditions, and (2) a procedure for deriving a robustness metric …

Spectrum Visualization And Measurement Of Power Parameters Of Microwave Wideband 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 envelope in a wide frequency range (several octaves), measuring of its power parameters, and detection of a narrowband 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.

Experimental Studies Assessing The Repeatability Of A Functional Modeling Derivation Method, Mark A. Kurfman, Michael E. Stock, Robert B. Stone, Jagan Rajan, Kristin L. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents the results of research attempts to substantiate repeatability and uniqueness claims of a functional model derivation method following a hypothesis generation and testing procedure outlined in design research literature. Three experiments are constructed and carried out with a participant pool that possesses a range of engineering design skill levels. the experiments test the utility of a functional model derivation method to produce repeatable functional models for a given product among different designers. in addition to this, uniqueness of the functional models produced by the participants is examined. Results indicate the method enhances repeatability and leads designers toward …

Mapping Function To Failure Mode During Component Development, Irem Y. Tumer, Robert B. Stone

Mechanical and Aerospace Engineering Faculty Research & Creative Works

When designing aerospace systems, it is essential to provide crucial failure information for failure prevention. Failure modes and effect types of analyses and prior engineering knowledge and experience are commonly used to determine the potential modes of failures a product might encounter during its lifetime. When new products are being considered and designed, this knowledge and information is expanded upon to help designers extrapolate based on their similarity with existing products and the potential design tradeoffs. in this work, we aim to enhance this process by providing design-aid tools which derive similarities between functionality and failure modes. Specifically, this paper …

Proper Orthogonal Decomposition Based Modeling And Experimental Implementation Of A Neurocontroller For A Heat Diffusion System, Prashant Prabhat, S. N. Balakrishnan, Dwight C. Look, Radhakant Padhi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Experimental implementation of a dual neural network based optimal controller for a heat diffusion system is presented. Using the technique of proper orthogonal decomposition (POD), a set of problem-oriented basis functions are designed taking the experimental data as snap shot solutions. Using these basis functions in Galerkin projection, a reduced-order analogous lumped parameter model of the distributed parameter system is developed. This model is then used in an analogous lumped parameter problem. A dual neural network structure called adaptive critics is used to obtain optimal neurocontrollers for this system. In this structure, one set of neural networks captures the relationship …

How To Establish Successful Cooperative Student Learning Centers For Stem Courses, Ronald James Bieniek, Douglas R. Carroll, Cesar Mendoza, Oran Allan Pringle, Ekkehard Sinn, Kai-Tak Wan, Donald C. Wunsch

Physics Faculty Research & Creative Works

Students learn more if they are actively involved in the learning process, particularly in a cooperative manner. Several UMR faculty have operated course-based learning centers (LCs) as part of the campus-wide Learning Enhancement Across Disciplines (LEAD) Program of student learning assistance and enhancement. LCs are designed to assist large numbers of students in a cost- and time-efficient manner that promotes student engagement without requiring undue amounts of faculty time. Course instructors spend time in the open learning environment of the LC, in lieu of office hours, guiding students to master course material and skills in their evolution from novice to …

Dynamics Of Bulk And Adsorbed Poly(Vinyl Acetate), Frank D. Blum, Robert D. O'Connor

Materials Science and Engineering Faculty Research & Creative Works

We have recently completed a series of experiments on methyl-labeled poly(vinyl acetate)-d3, (PVAc-d3)1 and poly(methyl acrylate)-d3 (PMA-d3).234 the systems have been studied as a function of the adsorbed amount, molecular weight, and presence of a protonated overlayer. Using deuterium line shape analysis, we have found that around the glass transition temperature, the adsorbed polymers show the presence of a motional gradient. Polymer segments near the silica-polymer interface have less mobility than the bulk polymer and those near the polymer-air interface are more mobile than those of the bulk polymer. A schematic representation of the motional gradient is shown in Figure …

A Heuristic Dynamic Programming Based Power System Stabilizer For A Turbogenerator In A Single Machine Power System, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp the low frequency power system oscillations. To overcome the drawbacks of conventional PSS (CPSS), numerous techniques have been proposed in the literature. Based on the analysis of existing techniques, a novel design of power system stabilizer (PSS) based on heuristic dynamic programming (HDP) is proposed in this paper. HDP combining the concepts of dynamic programming and reinforcement learning is used in the design of a nonlinear optimal power system stabilizer. The proposed HDP based PSS is evaluated against the conventional power …

A Novel Dual Heuristic Programming Based Optimal Control Of A Series Compensator In The Electric Power Transmission System, Jung-Wook Park, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the dual heuristic programming (DHP) optimization algorithm is used for the design of a nonlinear optimal neurocontroller that replaces the proportional-integral (PI) based conventional linear controller (CONVC) in the internal control of a power electronic converter based series compensator in the electric power transmission system. The performance of the proposed DHP based neurocontroller is compared with that of the CONVC with respect to damping low frequency oscillations. Simulation results using the PSCAD/EMTDC software package are presented.

Electrochemical And Hydrodynamic Interferences On The Performance Of An Oxygen Microsensor With Built-In Electrochemical Microactuator, Chang-Soo Kim, Chae-Hyang Lee

Electrical and Computer Engineering Faculty Research & Creative Works

An in situ self-diagnostic technique for a dissolved oxygen microsensor is proposed in an effort to devise an intelligent microsensor system with an integrated electro-chemical actuation electrode. With a built-in platinum microelectrode that surrounds the microsensor, two kinds of microenvironments (oxygen-saturated or oxygen-depleted phases) can be created by water electrolysis depending on the polarity. The functionality of the microsensor can be checked during these microenvironment phases. The polarographic oxygen microsensor is fabricated on a flexible polyimide substrate (Kapton/sup ©/) and the influences of electrochemical and hydrodynamic conditions on the sensor responses have been investigated.

Fdtd Data Extrapolation Using Multilayer Perceptron (Mlp), H. Goksu, David Pommerenke, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

This work compares MLP with the matrix pencil method, a linear eigenanalysis-based extrapolator, in terms of their effectiveness in finite difference time domain (FDTD) data extrapolation. Matrix pencil method considers the signal as superposed complex exponentials while MLP considers each time step to be a nonlinear function of previous time steps.

Measurement Of Mode Patterns In A High-Power Microwave Cavity, Sergey Kharkovsky, U. C. Hasar

Electrical and Computer Engineering Faculty Research & Creative Works

A wet thermal paper method for measuring of mode patterns and heat distributions in a high-power microwave multimode cavity is developed. The exposure time of the paper is evaluated. It is shown that this method allows measuring and recording mode patterns in the loaded and unloaded cavity, and the heat distribution inside the cavity with a load movement. The mode patterns and heat distributions along horizontal and vertical planes of the cavity are presented. Possible applications of the method in medicine and biology are discussed, and a calibration protocol of a microwave oven for microwave radiation exposure on cell cultures …

Probabilistic Neural Networks For Multi-Class Tissue Discrimination With Gene Expression Data, Rui Xu, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

With the emergence and rapid advancement of DNA microarray technologies, construction of gene expression profiles for different cancer types has already become a promising means for cancer diagnosis and treatment. Most previous research has focused on binary classification. Here, we use a probabilistic neural network (PNN) for multi-classification of cancer data. The experimental results demonstrate the effectiveness of the PNN in addressing gene expression data.

Speaking And Writing Proficiency Of International Graduate Students In Elective, Mentoring Environments, Steve Eugene Watkins, Randy Green

Electrical and Computer Engineering Faculty Research & Creative Works

Technical communication skills are critical for non-native speakers who must study and interact in English-only professional settings. Often, formal instruction to pass admission thresholds and other minimum requirements are not sufficient to attain proficiency. This paper describes elective, long-term programs that provide systematic opportunities for both speaking and writing development. These programs are tailored to international students through the key features of individualized activities, applied task-oriented practice, and social interaction. The elective programs attract and retain participants with interest and need for high-level language proficiency. Program evaluations show that participating graduate students give primary credit for their growing fluency to …

Adaptive Critic Neural Network-Based Controller For Nonlinear Systems With Input Constraints, Pingan He, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel adaptive critic-Based multilayer neural network (NN) controller in discrete-time is designed to deliver a desired tracking performance for a class of nonlinear systems in the presence of magnitude constraints on the input. Reinforcement learning scheme in discrete time is proposed for the NN controller, where the action generating NN learning is performed based on a certain performance measure, which is supplied from a critic. using the Lyapunov approach and with a novel weight update, the uniform ultimately boundedness (UUB) of the closed loop tracking error and weight estimates are shown. the adaptive critic NN does not require an …

A Simplified Two Dimensional Soil Model For The New Madrid Seismic Zone, Wei Zheng, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The New Madrid Seismic Zone (NMSZ) is one of the most seismically susceptible areas in United States. Deep alluvial soil deposit of the Mississippi Embayment overlies the NMSZ, which remains a major uncertainty for site response analysis. based on the experiment data, a simple constitutive soil model is developed to take into account the influence of the effective confining pressure on the shear modulus degradation and the viscous damping development in soil, and also the shear strain and the plasticity index. This model is implemented into a two-dimensional finite element code in the time domain. the Rayleigh viscous damping scheme …

Missile Longitudinal Autopilot Design Using A New Suboptimal Nonlinear Control Method, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A missile longitudinal autopilot is designed using a new nonlinear control synthesis technique called the θ-D approximation. The particular θ-D methodology used is referred to as the θ-D H2 design. The technique can achieve suboptimal closed-form solutions to a class of nonlinear optimal control problems in the sense that it solves the Hamilton-Jacobi-Bellman equation approximately by adding perturbations to the cost function. An interesting feature of this method is that the expansion terms in the expression for suboptimal control are nothing but solutions to the state-dependent Riccati equations associated with this class of problems. The θ-D H2 design has the …

Vibration Analysis Via Neural Network Inverse Models To Determine Aircraft Engine Unbalance Condition, Xiao Hu, J. L. Vian, Donald C. Wunsch, J. R. Slepski

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes the use of artificial neural networks (ANNs) with the vibration data from real flight tests for detecting engine health condition - mass imbalance herein. Order-tracking data, calculated from time series is used as the input to the neural networks to determine the amount and location of mass imbalance on aircraft engines. Several neural network methods, including multilayer perceptron (MLP), extended Kalman filter (EKF) and support vector machines (SVMs) are used in the neural network inverse model for the performance comparison. The promising performances are presented at the end.

Output Feedback Force Control For A Parallel Turning Operation, Raghusimha Sudhakara, Robert G. Landers

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Parallel machine tools (i.e., machine tools capable of cutting a part with multiple tools simultaneously but independently) are being utilized more and more to increase operation productivity, decrease setups, and reduce floor space. Process control is the utilization of real-time process sensor information to automatically adjust process parameters (e.g., feed, spindle speed) to increase operation productivity and quality. To date, however, these two technologies have not been combined. This paper describes the design of an output feedback controller for a parallel turning operation that accounts for the inherent nonlinearities in the force process. An analysis of the process equilibriums explains …

A Unique Fault-Tolerant Design For Flying Capacitor Multilevel Inverters, X. 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 scarifying power converting quality. This paper also discusses the capacitor balancing approach under fault-conditions, which is an essential part of controlling flying capacitor type multilevel inverters. Suggested fault diagnosing methods are also discussed in this paper. …

Printed Circuit Board Emi Source Mechanisms, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

This tutorial paper reviews the basic mechanisms by which signal voltages and currents on a printed circuit board produce unintentional radiated emissions.

Application Of A Finite Element Model Update Technique To Detect Damage In A Beam Structure, Madhu Kumar Vattipulusu

Masters Theses

"The interest in the ability to monitor a structure and detect damage at the earliest possible stage is pervasive throughout the civil, mechanical and aerospace engineering communities. The thesis focuses on the application of a finite element model updating technique to monitor and detect damage in beams. A Sensitivity Based Element-by- Element (SBEBE) methodology is chosen as the finite element model updating technique. In this method, damage is detected by updating a finite element model with test data obtained from "healthy" and "damaged" structures and observing the relative changes in the updated finite element models. The performance, efficiency and sensitivity …

Numerical Modeling Of Focused Remediation Using A Groundwater Circulation Well, Gretchen R. Miller

Masters Theses

"Groundwater circulation wells (GCWs) allow for the in situ treatment of contaminated water resources. Focused remediation with a GCW could be used to treat groundwater before it enters an existing domestic well already in use. GCWs have been installed at the former Nebraska Ordnance Plant; the model originally developed for these was slightly modified and used to perform a feasibility study of a focused remediation system.

If the focused remediation system works properly, the capture zone of the domestic well should be within the recharge zone of the GCW. Deterministic modeling with capture zone analysis indicated that a GCW installed …

Performance & Project Spirit Of Student Design Competition Teams, Bradley Marcus Davis

Masters Theses

"Student design competition teams present a valuable research possibility in the field of work group research. They are widely available and present greater learning opportunities than do class project groups. This study intended to create an instrument to measure the level of project spirit and team performance in order to establish a link between these two concepts. In the present study, nine student design competition teams from the University of Missouri - Rolla (UMR) campus (n = 186) were surveyed. The results indicate a strong correlation of the project spirit variables (project culture, project commitment, project citizenship, and project satisfaction) …

Common- And Differential-Mode Signaling And Filtering, Zhe Li

Masters Theses

"Common-mode chokes are widely used as suppression filters against interference of common-mode noise in high-speed differential signaling. This thesis focuses on investigating the characteristics of common-mode chokes. Mixed-mode S-parameters are presented as a useful concept for explaining the modal operation of differential circuits.

Three methods for measuring common-mode and differentia-mode S-parameters of common-mode chokes are demonstrated. The three methods involve (1) ABCD chain matrix, 2) using hybrid couplers and 3) modal decomposition. Each measurement method provides a specific level of accuracy. The modal decomposition method can work up to 10GHz.

SPICE equivalent circuit model of common-mode chokes and the extraction …

Emergence And Artificial Life, Nil H. Kilicay, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper focuses on emergent phenomena and the utilization of computer simulations, basically agent-based modeling to understand emergent phenomena. Agent-based simulation models have a promising future in the social sciences, from management to economies, political science, sociology and anthropology. This paper attempts to realize their full scientific potential by reviewing recent applications in engineering management and addresses the set of challenges confronted by this method. Common methodology for constructing an agent-based model is also discussed with the aim of highlighting how artificial life and management can be brought together to develop decision making aid tools.

An Enhanced Least-Squares Approach For Reinforcement Learning, Hailin Li, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper presents an enhanced least-squares approach for solving reinforcement learning control problems. Model-free least-squares policy iteration (LSPI) method has been successfully used for this learning domain. Although LSPI is a promising algorithm that uses linear approximator architecture to achieve policy optimization in the spirit of Q-learning, it faces challenging issues in terms of the selection of basis functions and training samples. Inspired by orthogonal least-squares regression (OLSR) method for selecting the centers of RBF neural network, we propose a new hybrid learning method. The suggested approach combines LSPI algorithm with OLSR strategy and uses simulation as a tool to …

Mechanical Property Characterization Of Mouse Zona Pellucida, Yu Sun, Kai-Tak Wan, K. P. Roberts, J. C. Bischof, B. J. Nelson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Previous intracytoplasmic sperm injection (ICSI) studies have indicated significant variation in ICSI success rates among different species. In mouse ICSI, the zona pellucida (ZP) undergoes a "hardening" process at fertilization in order to prevent subsequent sperm from penetrating. There have been few studies investigating changes in the mechanical properties of mouse ZP post fertilization. To characterize mouse ZP mechanical properties and quantitate the mechanical property differences of the ZP before and after fertilization, a microelectromechanical systems-based multiaxis cellular force sensor has been developed. A microrobotic cell manipulation system employing the multiaxis cellular force sensor is used to conduct mouse ZP …

Nonlinear H Infinity Missile Longitudinal Autopilot Design With Θ-D Method, Ming Xin, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a new nonlinear control synthesis technique, the theta- D method, is employed to design a missile longitudinal autopilot. The θ-D technique yields suboptimal solutions to nonlinear optimal control problems in the sense that it provides approximate solution to the Hamilton-Jacobi-Bellman (HJB) equation. Semi-global asymptotic stability can be achieved by manipulating the perturbation terms which are added to the cost function in developing a series solution. Furthermore, this method can be used to provide an approximate closed-form solution to the state dependent Riccati equation. The particular θ-D methodology adopted in this paper is referred to as θ-D H …