Digital Commons Network^™

Effective Use Of Process Capability Indices For Supplier Management, Elizabeth A. Cudney, David Drain

Engineering Management and Systems Engineering Faculty Research & Creative Works

Process capability indices were originally invented to enable an organization to make economically sound decisions for process management. Process capability is a comparison of the voice of the process with the voice of the customer. Current practice is to use Cp and Cpk regardless of the validity of the underlying assumptions necessary for their use. Even if all necessary assumptions are satisfied, important problems can be missed if these indices are the sole process evaluation examined. Customer-supplier axioms are introduced to motivate more useful process evaluations and foster long-term harmonious relationships. This paper explores the alternative capability indices Cpm, Cpmk, …

Quantification Of Steroid Sex Hormones Using Solid-Phase Extraction Followed By Liquid Chromatography-Mass Spectrometry, Youssef Filali-Meknassi, Muriel Auriol, Craig D. Adams, Rao Y. Surampalli

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, the occurrence of trace amounts of natural and synthetic steroid estrogens in the aquatic environment was studied using liquid chromatography coupled with electrospray mass spectrometry, following solid-phase extraction (SPE). the SPE was performed with C18 and NH2 cartridges. the first objective was to develop a reliable method for analyzing steroid estrogens (resulting from human and animal excretions) in different matrices. the method developed was then applied to quantify the occurrence of natural and synthetic hormones (estrone [E1], 17β-estradiol [βE2], 17α-estradiol [αE2], estriol [E3], and 17α-ethinylestradiol [EE2]) in environmental samples in surface water and wastewater treatment plant (WWTP) …

Error Performance Of Double Space Time Transmit Diversity Systems, Jingxian Wu, Y. Rosa Zheng, Ashwin Gumaste, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

The theoretical error performance of double space time transmit diversity (DSTTD) system with optimum combining receiver is analyzed in this paper. by employing both spatial multiplexing and transmit diversity in one system, DSTTD provides practical tradeoff between system spectral efficiency and diversity gain. We derive exact analytical expressions to describe the symbol error rate for DSTTD systems. The effects of both diversity gain and antenna interference introduced by spatial multiplexing are quantified in the results. In addition, the performance of DSTTD system with successive interference cancellation is also investigated. Simulation results are in excellent agreement with the theoretical results obtained …

A Comparison Of Techniques To Forecast Consumer Satisfaction For Vehicle Ride, Elizabeth A. Cudney, David Drain, Kenneth M. Ragsdell, Kioumars Paryani

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper presents a comparison of methods for the identification of a reduced set of useful variables using a multidimensional system. the Mahalanobis-Taguchi System and a standard statistical technique are used reduce the dimensionality of vehicle ride based on consumer satisfaction ratings. the Mahalanobis-Taguchi System and cluster analysis are applied to vehicle ride. the research considers 67 vehicle data sets for the 6 vehicle ride parameters. This paper applies the Mahalanobis-Taguchi System to forecast consumer satisfaction and provides a comparison of results with those obtained from a standard statistical approach to the problem. Copyright © 2007 SAE International.

Incorporating The Effects Of Magnetic Saturation In A Coupled-Circuit Model Of A Claw-Pole Alternator, Hua Bai, Steven Pekarek, Jerry L. Tichenor, Walter Eversman, Duane J. Buening, Gregory R. Holbrook, Ronald J. Krefta

Electrical and Computer Engineering Faculty Research & Creative Works

A method of representing the effects of magnetic saturation in a coupled-circuit model of a claw-pole alternator is presented. In the approach considered, the airgap flux density produced by each winding is expressed as a function of magnetic operating point. A challenge in the implementation is that the airgap flux densities consist of several significant harmonics, each of which changes at a distinct rate as iron saturates. Despite this complication, it is shown that relatively simple measurements can be used to determine model parameters. The model is implemented in the analysis of several alternator/rectifier systems using a commercial state-model-based circuit …

Crosslinking 3d Assemblies Of Silica Nanoparticles (Aerogels) By Surface-Initiated Free Radical Polymerization Of Styrene And Methylmethacrylate, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik

Chemistry Faculty Research & Creative Works

Quasi-stable, ultra-low density, three-dimensional assemblies of nanoparticles are referred to as aerogels. Aerogels are open-cell foams derived from supercritical fluid (SCF) drying of wet gels. Their large internal void space is responsible for low dielectric constants, low thermal conductivities and high acoustic impedance. At the same time though those materials are fragile and impractical for high load applications. The fragility problem has been addressed by casting a thin conformal polymer coating over the entire internal porous surface of the nanostructure.1 That process is referred to as crosslinking. The coating connects chemically skeletal nanoparticles and renders interparticle necks wider. Thus, the …

A Mössbauer Spectral Study Of The Gdco₄₋ₓfeₓb Compounds, Fernande Grandjean, Raphäel P. Hermann, Eustachy S. Popiel, Gary J. Long

Chemistry Faculty Research & Creative Works

The iron-57 Mössbauer spectra of the GdCo_4-xFe_xB compounds, where x is 0.10, 0.15, 0.20, 0.25, 1, 2, 2.5, and 2.6, have been measured at room temperature and reveal relatively small iron hyperfine fields of approximately 12-18 T, relatively large quadrupole interactions of approximately +0.9 and -1 mm/s, and three very different types of spectra for x=0.10 and 0.15, x=0.25, 1, and 2, and x=2.5 and 2.6. The differences result from both the different easy magnetization directions in these compounds and the different cobalt and/or iron occupancies of the crystallographic 2c and 6i sites. The spectra have …

Near Optimal Output-Feedback Control Of Nonlinear Discrete-Time Systems In Nonstrict Feedback Form With Application To Engines, Peter Shih, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

A novel reinforcement-learning based output-adaptive neural network (NN) controller, also referred as the adaptive-critic NN controller, is developed to track a desired trajectory for a class of complex nonlinear discrete-time systems in the presence of bounded and unknown disturbances. The controller includes an observer for estimating states and the outputs, critic, and two action NNs for generating virtual, and actual control inputs. The critic approximates certain strategic utility function and the action NNs are used to minimize both the strategic utility function and their outputs. All NN weights adapt online towards minimization of a performance index, utilizing gradient-descent based rule. …

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 …

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 …

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.

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 …

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

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 …

Identifying Behavioral Characteristics Of High School Principals Providing Leadership In Reforming Iowa High Schools, Nadene E. Davidson

Dissertations and Theses @ UNI

Technological advances and the changing world have created new challenges in preparing our youth to lead satisfying lives in the twenty-first century. Current literature supports the case that change is needed in our high schools to move from the factory preparation model to become more personalized learning communities preparing students for life in a global community. This reinvented high school will require reinvented leadership to guide the process of high school reform. The purpose of this study was to identify behavioral characteristics of high school principals providing leadership in reforming Iowa high schools.

Interviews were conducted with educators from two …

Product Family Design Knowledge Representation, Aggregation, Reuse, And Analysis, Jyotirmaya Nanda, Henri Thevenot, Timothy W. Simpson, Robert B. Stone, Matt R. Bohm, Steven B. Shooter

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A flexible information model for systematic development and deployment of product families during all phases of the product realization process is crucial for product-oriented organizations. In current practice, information captured while designing products in a family is often incomplete, unstructured, and is mostly proprietary in nature, making it difficult to index, search, refine, reuse, distribute, browse, aggregate, and analyze knowledge across heterogeneous organizational information systems. To this end, we propose a flexible knowledge management framework to capture, reorganize, and convert both linguistic and parametric product family design information into a unified network, which is called a networked bill of material …

Robust/Optimal Temperature Profile Control Of A High-Speed Aerospace Vehicle Using Neural Networks, Vivek Yadav, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An approximate dynamic programming (ADP)-based suboptimal neurocontroller to obtain desired temperature for a high-speed aerospace vehicle is synthesized in this paper. a 1-D distributed parameter model of a fin is developed from basic thermal physics principles. ldquoSnapshotrdquo solutions of the dynamics are generated with a simple dynamic inversion-based feedback controller. Empirical basis functions are designed using the ldquoproper orthogonal decompositionrdquo (POD) technique and the snapshot solutions. a low-order nonlinear lumped parameter system to characterize the infinite dimensional system is obtained by carrying out a Galerkin projection. an ADP-based neurocontroller with a dual heuristic programming (DHP) formulation is obtained with a …

Quiet, Do Not Disturb: Prying Open The Door To Examine Our Worlds Of Testing And Assessment, Amma Akrofi, Carole Janisch, Mellinee Lesley, Robin Griffith, Xiaoming Liu

Essays in Education

Teacher educators recount their personal experiences related to testing and assessment. Through the examination of these experiences stemming from collegial conversations, the individuals have come to better understand the issues and challenges their university students, preservice and inservice teachers, will face in their classroom settings. Along with theory and research, the realities encountered by these individuals become “course capital.” The content of their current and future university literacy courses and assessment courses reflects their renewed emphasis on responsive and child-centered instruction as opposed to the untoward focus on testing.

The Socio-Economic Implications Of Teachers Supply Patterns On The Teaching Profession In Nigeria, S. V. Kobiowu

Essays in Education

Various scholars and researches have identified a number of traditions guiding the development of teacher education programmes. These include “the academic” tradition, “the social efficiency” tradition, “the developmentalist” tradition, otherwise referred to as the “personalist” or “humanist” tradition, and “the social reconstructionist” tradition. Education is the pivot of development in all countries, (Nigeria is no exception), and the availability of well-trained and highly qualified teachers is central to the supply of human capital needed to promote qualitative education. The training of teachers in Nigeria, which started in 1859 with the establishment of “The Training Institute”, at Abeokuta, has metamorphosed into …

Methane Potential Of Upper Fort Union Formation Sandstones, Campbell County, Wyoming, Michael J. Blackstone

Theses and Dissertations

Coalbed methane has been produced from the coalbeds of the Upper Fort Union Formation in the Powder River Basin for many years. The sandstones associated with these coals have also proven to be gas-charged, but industry has done little with the sandstones thus far. The purpose of this study is to determine the paleoenvironrnent responsible for the deposition of the coal and sandstone bodies in an attempt to locate gas-charged sandstone bodies in the Tongue River Member of the Fort Union Formation.

The 30-mile by 90-mile study area was chosen because of the presence of a decrease in thick coalbed …

Resolving Terrain Effects In Borehole Temperature Profiles, Shannon M. Heinle

Theses and Dissertations

The study of borehole paleoclimatology aids scientists in determining past climate changes and in understanding current climate trends. Accurate borehole temperature logs are necessary to obtain a useful temperature profile. However, as many climate workers have discovered, borehole temperature profiles can have many causes of inaccuracy. Uncertainties associated with borehole data include errors stemming from temperature measurement, depth measurement, thermophysical property measurements, and terrain effects. Terrain effects include topography, changes in land cover over time, direct and diffused sun radiation, and groundwater flow.

This study focused on specific terrain effects influencing borehole temperature profiles in the United States borehole dataset …

Dialogic Communication In Collaborative Problem Solving Groups, Robert B. Innes

International Journal for the Scholarship of Teaching & Learning

Discourse, especially dialogic communication between students in collaborative problem-solving groups, plays a central role in educational reforms informed by learning science. This study examined the quality of discourse in problem-based learning groups in a university course. The study found a low incidence of high quality dialogue (dialogic communication, elaboration and co-construction of ideas, productive disciplinary discourse) in 12 one-hour planning meetings. The most competent students took leadership in groups and made the majority of the conceptual contributions. Although there was a reasonable amount of time spent connecting theories to cases, there was little time spent in high-level analysis and very …

What Motivates Students To Provide Feedback To Teachers About Teaching And Learning? An Expectancy Theory Perspective, Johnette Caulfield

International Journal for the Scholarship of Teaching & Learning

The purpose of this empirical research study was to investigate what motivates students to provide formative anonymous feedback to teachers regarding their perceptions of the teaching and learning experience in order to improve student learning. Expectancy theory, specifically Vroom’s Model, was used as the conceptual framework for the study. Multiple regression analysis was employed to test both the valence and force equations. Statistically significant results indicated that students’ motivation was dependent upon the importance to them of improving the value of the class and of future classes, and the expectation that their formative feedback would lead to increased value for …