Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Missouri University of Science and Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 12271 - 12300 of 21751

Full-Text Articles in Engineering

A Method Of Including Switching Loss In Electro-Thermal Simulations, Jonathan W. Kimball Aug 2004

A Method Of Including Switching Loss In Electro-Thermal Simulations, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

Often, power electronics systems are simulated with ideal switching elements, perhaps augmented with conduction loss models. A behavioral model is proposed that also includes switching loss and is independent of switching frequency. Therefore, it is suitable for variable frequency control methods, including hysteresis, delta modulation, and random PWM. Models have been realized in Dymola using voltage-controlled voltage sources, current sources, logic, and additional ideal switches. Thermal ports are included to facilitate electro-thermal simulation. A method for parameter extraction is demonstrated using experimental data from standard PWM.

Go to article

A Study On The Correspondence Of Common-Mode Current In Electromagnetic Radiation From A Pcb With A Guard-Band, Yoshiki Kayano, Motoshi Tanaka, Hiroshi Inoue, James L. Drewniak Aug 2004

A Study On The Correspondence Of Common-Mode Current In Electromagnetic Radiation From A Pcb With A Guard-Band, Yoshiki Kayano, Motoshi Tanaka, Hiroshi Inoue, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A PCB, in which the ground plane has a finite width and the trace has unbalanced positioning, can result in common-mode (CM) radiation. So far, CM current which is generated by the unbalance of a trace and ground plane has been investigated by experiment and numerical method. It was clarified that CM current is well explained the radiation from PCB up to a few hundred megahertz, and addition of a guard band geometry, which is well connected to the ground plane, can be effective in suppressing the CM current. But it is seemed to be insufficient description for the phenomena …

Go to article

Effects Of Open Stubs Associated With Plated Through-Hole Vias In Backpanel Designs, Shaowei Deng, Jingkun Mao, Todd H. Hubing, James L. Drewniak, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander, Chen Wang Aug 2004

Effects Of Open Stubs Associated With Plated Through-Hole Vias In Backpanel Designs, Shaowei Deng, Jingkun Mao, Todd H. Hubing, James L. Drewniak, Jun Fan, James L. Knighten, Norman W. Smith, Ray Alexander, Chen Wang

Electrical and Computer Engineering Faculty Research & Creative Works

Plated through-hole (PTH) vias are commonly used in printed circuit boards. They usually leave open stubs if the signal(s) does not transition the entire depth of the board. These open stubs can have a negative impact on signal transmission. This summary reports the investigation of the impact of the open via stubs in a typical backpanel design.

Go to article

Expert System Algorithms For Identifying Radiated Emission Problems In Printed Circuit Boards, Hwan-Woo Shim, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff, James L. Drewniak, David Pommerenke, R. Kaires Aug 2004

Expert System Algorithms For Identifying Radiated Emission Problems In Printed Circuit Boards, Hwan-Woo Shim, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff, James L. Drewniak, David Pommerenke, R. Kaires

Electrical and Computer Engineering Faculty Research & Creative Works

Radiated emission algorithms for a printed circuit board EMC expert system are described. The expert system mimics the thinking processes that human EMC engineers would use to analyze circuit boards and make design recommendations. Working with limited information about the enclosure, cables or the exact nature of the signals, the expert system evaluates different structures on the printed circuit board looking for potentially strong radiated emission sources. Results obtained from the analysis of a sample printed circuit board are provided to demonstrate how the expert system quickly identifies problems that would otherwise be difficult to locate.

Go to article

Extracting R, L, G, C Parameters Of Dispersive Planar Transmission Lines From Measured S-Parameters Using A Genetic Algorithm, Jianmin Zhang, Marina Koledintseva, James L. Drewniak, Giulio Antonini, Antonio Orlandi, Konstantin Rozanov Aug 2004

Extracting R, L, G, C Parameters Of Dispersive Planar Transmission Lines From Measured S-Parameters Using A Genetic Algorithm, Jianmin Zhang, Marina Koledintseva, James L. Drewniak, Giulio Antonini, Antonio Orlandi, Konstantin Rozanov

Electrical and Computer Engineering Faculty Research & Creative Works

Signal integrity (SI) analysis of printed circuit boards for high-speed digital design requires information on the perunit-length R, L, G, C parameters of the transmission lines. However, these are not always available when the property of the dielectric medium used in the board is unknown. A method to extract R, L, G, and C parameters from parallel-plate and strip transmission line geometries is proposed. It is based on measured scattering parameters and analytical modeling. A genetic algorithm (GA) is used to optimize the extraction by minimizing the frequency domain discrepancy between an objective function, which is the measured scattering matrix …

Go to article

Feedback Linearization Based Power System Stabilizer Design With Control Limits, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Jagannathan Sarangapani Aug 2004

Feedback Linearization Based Power System Stabilizer Design With Control Limits, Wenxin Liu, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

In power system controls, simplified analytical models are used to represent the dynamics of power system and controller designs are not rigorous with no stability analysis. One reason is because the power systems are complex nonlinear systems which pose difficulty for analysis. This paper presents a feedback linearization based power system stabilizer design for a single machine infinite bus power system. Since practical operating conditions require the magnitude of control signal to be within certain limits, the stability of the control system under control limits is also analyzed. Simulation results under different kinds of operating conditions show that the controller …

Go to article

Microwave Reflection Properties Of Concrete Periodically Exposed To Chloride Solution Of 3% Salinity And Compression Force, Joseph Toby Case, Shanup Peer, Eric Gallaher, R. Zoughi Aug 2004

Microwave Reflection Properties Of Concrete Periodically Exposed To Chloride Solution Of 3% Salinity And Compression Force, Joseph Toby Case, Shanup Peer, Eric Gallaher, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Corrosion of steel rebar in a concrete structure compromises its structural integrity and hence its performance. Chloride intrusion into concrete can lead to depassivation of the steel and initiation of corrosion. Methods exist to detect chlorides in concrete, but the practical use of many of these may be problematic because they are destructive and time consuming, and cannot be used to analyze large structures. Microwave nondestructive evaluation techniques applied to mortar have proven successful for detecting mixture constituents, chloride ingress, and cure-state monitoring. In this paper several concrete samples are cyclically soaked in distilled water and saltwater while also experiencing …

Go to article

A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak Aug 2004

A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A three-dimensional subgridding algorithm for the finite difference time domain (FDTD) method is proposed in this paper. The method is based on interpolation of electric and magnetic current densities. The coarse-fine mesh ratio can be either 1:2 or 1:3. Results of a test model utilizing a lossless cavity excited with a dipole show no tendency of instability after 500000 time steps. The reflection in time domain at the subgridding interface was calculated to test the accuracy of the subgridding algorithm.

Go to article

An Extrapolation Procedure To Shorten Time Domain Simulations, Giuseppe Selli, James L. Drewniak, David Pommerenke Aug 2004

An Extrapolation Procedure To Shorten Time Domain Simulations, Giuseppe Selli, James L. Drewniak, David Pommerenke

Electrical and Computer Engineering Faculty Research & Creative Works

Time-domain simulation algorithms are widely used in the anaylsis and design of electromagnetic systems. Many of them are characterized by high Q's. Thus, the simulations have to employ many time steps in order to achieve a complete characterization of these systems. This time-consuming computational effort can be avoided if the late instants of time are extrapolated by applying a parametric estimation algorithm. An optimized implementation of a time-domain extrapolation method and a stop criterion are discussed in this paper. The latter criterion is based upon a normalized squared difference between the waveforms extrapolated from two different sets of initial data …

Go to article

Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen Aug 2004

Anticipating Emi And On-Board Interference In Automotive Platforms, Shishuang Sun, Geping Liu, David Pommerenke, James L. Drewniak, Richard W. Kautz, Chingchi Chen

Electrical and Computer Engineering Faculty Research & Creative Works

A dual-step MTL / FDTD strategy is proposed for anticipating full-vehicle level EMI. In the first step, the current distribution along a cable bundle connecting to electronic modules an an automotive platform is calculated using multi-conductor transmission-line (MTL) models. In order to account for common-mode discontinuities on the vehicle chassis, e.g., slots, 3D full-wave modeling (FDTD) is used to determine radiation impedances, which are thereafter incorporated in the MTL models for compensating the radiation power loss. In the second step, the obtained currents are implemented as impressed current sources in full-vehicle full-wave modeling using an FDTD multi-wire subcelluar algorithm. Thus, …

Go to article

Series-Parallel Approaches And Clamp Methods For Extreme Dynamic Response With Advanced Digital Loads, Philip T. Krein, Jonathan W. Kimball Aug 2004

Series-Parallel Approaches And Clamp Methods For Extreme Dynamic Response With Advanced Digital Loads, Philip T. Krein, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

The series-input parallel-output dc-dc converter combination provides inherent sharing among the converters. With conventional controls, however, this sharing is unstable. Recent literature work proposes complicated feedback loops to correct the problem, at the cost of dynamic performance. This paper shows that a simple sensorless current mode control stabilizes sharing with fast dynamics suitable for advanced digital loads. With this control in place, a "super-matched" current sharing control emerges. Sharing occurs through transients, limited only by the energy limits of the converters. The control approach has considerable promise for high-performance voltage regulator modules. For even faster response, clamping techniques are proposed.

Go to article

Investigation Into The Ultrasonic Setting Of Glass Ionomer Cements : Part Ii Setting Times And Compressive Strengths, E. Twomey, Mark R. Towler, C. M. Crowley, J. Doyle, S. Hampshire Jul 2004

Investigation Into The Ultrasonic Setting Of Glass Ionomer Cements : Part Ii Setting Times And Compressive Strengths, E. Twomey, Mark R. Towler, C. M. Crowley, J. Doyle, S. Hampshire

Chemical and Biochemical Engineering Faculty Research & Creative Works

The ultrasonic setting of glass ionomer cements (GIC) was discussed. It was observed that the ultrasonic setting resulted in improvements of compressive strength. An increase in the PAA molecular weight from PAA50 to PAA200 resulted in an increase in the strength, but with a further increase in the PAA molecular weight to PAA450, there was a reduction in the strength. Results show that the strength of the ultrasonically set materials after 1 day were close to the values for the 7 days chemically set samples.

Go to article

A Framework For Trajectory Based Visual Event Retrieval, Ilker Ersoy, Filiz Bunyak, S. R. Subramanya Jul 2004

A Framework For Trajectory Based Visual Event Retrieval, Ilker Ersoy, Filiz Bunyak, S. R. Subramanya

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a framework of a system for the query and retrieval of video data based on video events in huge video repositories. the events are formulated using domain-independent event primitives which are represented by spatio-temporal relationships between objects in the video scenes. Complex events are expressible as combinations of simpler events. This facilitates support of event queries from a variety of points of view. in addition, the framework is expected to provide adaptability of the framework to multiple domains.

Go to article

Performance Evaluation Of Block-Based Motion Estimation Algorithms And Distortion Measures, S. R. Subramanya, Hiral Patel, Ilker Ersoy Jul 2004

Performance Evaluation Of Block-Based Motion Estimation Algorithms And Distortion Measures, S. R. Subramanya, Hiral Patel, Ilker Ersoy

Electrical and Computer Engineering Faculty Research & Creative Works

Motion estimation is an important component in video compression schemes which impacts the encoder performance and the quality of the reconstructed video sequence. Block-Based techniques are the most popular among the several motion estimation techniques used in practice due to their simplicity allowing efficient hardware implementations. the quality of motion predicted frame and the speed of motion vector computation are the primary measures of performance of motion estimation schemes. the video compression standards only specify the syntax of the bitstream and not any specifics of the motion estimation techniques. Thus, the knowledge of the workings and performance of commonly used …

Go to article

Artificial Neural Network Modeling Of Rf Mems Resonators, Yongjae Lee, Yonghwa Park, Feng Niu, Bonnie Bachman, K. C. Gupta, Dejan Filipovic Jul 2004

Artificial Neural Network Modeling Of Rf Mems Resonators, Yongjae Lee, Yonghwa Park, Feng Niu, Bonnie Bachman, K. C. Gupta, Dejan Filipovic

Economics Faculty Research & Creative Works

In this article, a novel and efficient approach for modeling radio‐frequency microelectromechanical system (RF MEMS) resonators by using artificial neural network (ANN) modeling is presented. In the proposed methodology, the relationship between physical‐input parameters and corresponding electrical‐output parameters is obtained by combined circuit/full‐wave/ANN modeling. More specifically, in order to predict the electrical responses from a resonator, an analytical representation of the electrical equivalent‐network model (EENM) is developed from the well‐known electromechanical analogs. Then, the reduced‐order, nonlinear, dynamic macromodels from 3D finite‐element method (FEM) simulations are generated to provide training, validating, and testing datasets for the ANN model. The developed ANN …

Go to article

Multilevel Inverters With Equal Or Unequal Sources For Dual-Frequency Induction Heating, B. Diong, S. Basireddy, Keith Corzine, Yakov L. Familiant Jul 2004

Multilevel Inverters With Equal Or Unequal Sources For Dual-Frequency Induction Heating, B. Diong, S. Basireddy, Keith Corzine, Yakov L. Familiant

Electrical and Computer Engineering Faculty Research & Creative Works

Most existing power supplies for induction heating equipment produce voltage at a single (adjustable) frequency. Recently, however, induction heating power supplies that produce voltage at two (adjustable) frequencies have been researched and even commercialized. Dual-frequency power supplies are a significant development for heat-treating workpieces with uneven geometries, such as gears, since different portions of such workpieces are heated dissimilarly at a single frequency and so require a two step process using a single-frequency power supply. On the other hand, a dual-frequency power supply can achieve the desired result for such workpieces in a one step process. This paper proposes the …

Go to article

Estimation Of Heart-Surface Potentials Using Regularized Multipole Sources, Daryl G. Beetner, R. Martin Arthur Jul 2004

Estimation Of Heart-Surface Potentials Using Regularized Multipole Sources, Daryl G. Beetner, R. Martin Arthur

Electrical and Computer Engineering Faculty Research & Creative Works

Direct inference of heart-surface potentials from body-surface potentials has been the goal of most recent work on electrocardiographic inverse solutions. We developed and tested indirect methods for inferring heart-surface potentials based on estimation of regularized multipole sources. Regularization was done using Tikhonov, constrained-least-squares, and multipole-truncation techniques. These multipole-equivalent methods (MEMs) were compared to the conventional mixed boundary-value method (BVM) in a realistic torso model with up to 20% noise added to body-surface potentials and ±1 cm error in heart position and size. Optimal regularization was used for all inverse solutions. The relative error of inferred heart-surface potentials of the MEM …

Go to article

Neural Network Stabilizing Control Of Single Machine Power System With Control Limits, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow Jul 2004

Neural Network Stabilizing Control Of Single Machine Power System With Control Limits, Wenxin Liu, Jagannathan Sarangapani, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Power system stabilizers are widely used to generate supplementary control signals for the excitation system in order to damp out the low frequency oscillations. This paper proposes a stable neural network (NN) controller for the stabilization of a single machine infinite bus power system. In the power system control literature, simplified analytical models are used to represent the power system and the controller designs are not based on rigorous stability analysis. This work overcomes the two major problems by using an accurate analytical model for controller development and presents the closed-loop stability analysis. The NN is used to approximate the …

Go to article

The Structure Of The High-Energy Spin Excitations In A High-Transition-Temperature Superconductor, S. M. Hayden, H. A. Mook, Pengcheng Dal, T. G. Perring, F. Doǧan Jun 2004

The Structure Of The High-Energy Spin Excitations In A High-Transition-Temperature Superconductor, S. M. Hayden, H. A. Mook, Pengcheng Dal, T. G. Perring, F. Doǧan

Materials Science and Engineering Faculty Research & Creative Works

In conventional superconductors, lattice vibrations (phonons) mediate the attraction between electrons that is responsible for superconductivity. The high transition temperatures (high-Tc) of the copper oxide superconductors has led to collective spin excitations being proposed as the mediating excitations in these materials. The mediating excitations must be strongly coupled to the conduction electrons, have energy greater than the pairing energy, and be present at Tc. The most obvious feature in the magnetic excitations of high-Tc superconductors such as YBa 2Cu3O6+x is the so-called 'resonance'. Although the resonance may be strongly coupled to the superconductivity, it is unlikely to be the main …

Go to article

Small Local Dynamic Fuzzy Logical Models For Large-Scale Power Systems, Jianjun Guo, Levent Acar, Badrul H. Chowdhury, Mariesa Crow Jun 2004

Small Local Dynamic Fuzzy Logical Models For Large-Scale Power Systems, Jianjun Guo, Levent Acar, Badrul H. Chowdhury, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

In the power system stability problems the primary actors in the mathematical system model are the differential equations defining the dynamic state variables of generation and load. These differential equations are coupled together by load flow equations. Mathematically the load flow equations are nonlinear algebraic equations. These differential equations and nonlinear algebraic equations form the mathematical Differential Algebraic Equations (DAE) model for the power system. The fuzzy set theory is commonly used in analysis of dynamical nonlinear systems. In this paper, we build a set of local dynamical fuzzy logic models for the differential equations, thus transforming the differential equations …

Go to article

Ascertaining The Importance Of Neurons To Develop Better Brain-Machine Interfaces, Justin C. Sanchez, Jose M. Carmena, Mikhail A. Lebedev, Miguel A.L. Nicolelis, John G. Harris, Jose C. Principe Jun 2004

Ascertaining The Importance Of Neurons To Develop Better Brain-Machine Interfaces, Justin C. Sanchez, Jose M. Carmena, Mikhail A. Lebedev, Miguel A.L. Nicolelis, John G. Harris, Jose C. Principe

Electrical and Computer Engineering Faculty Research & Creative Works

In the design of brain-machine interface (BMI) algorithms, the activity of hundreds of chronically recorded neurons is used to reconstruct a variety of kinematic variables. A significant problem introduced with the use of neural ensemble inputs for model building is the explosion in the number of free parameters. Large models not only affect model generalization but also put a computational burden on computing an optimal solution especially when the goal is to implement the BMI in low-power, portable hardware. In this paper, three methods are presented to quantitatively rate the importance of neurons in neural to motor mapping, using single …

Go to article

Successfully Blending Distance Students Into The On-Campus Classroom, Susan L. Murray, David Lee Enke, Sreeram Ramakrishnan Jun 2004

Successfully Blending Distance Students Into The On-Campus Classroom, Susan L. Murray, David Lee Enke, Sreeram Ramakrishnan

Engineering Management and Systems Engineering Faculty Research & Creative Works

As universities are increasingly embracing distance education technology, it is useful to examine the challenges and opportunities of technology in the classroom. This is especially true when the course contains on-campus local students in addition to students learning at a distance. A significant challenge commonly faced is how to remain flexible in presenting course materials while still having notes and other handouts in electronic format available before the lecture. Other challenges include creating and using lecture material that can be viewed at low resolution and low bandwidth, and getting distance students to interact with the instructor, on-campus students, and fellow …

Go to article

Testing Layered Interconnection Networks, Bin Liu, Fabrizio Lombardi, Nohpill Park, Minsu Choi Jun 2004

Testing Layered Interconnection Networks, Bin Liu, Fabrizio Lombardi, Nohpill Park, Minsu Choi

Electrical and Computer Engineering Faculty Research & Creative Works

We present an approach for fault detection in layered interconnection networks (LINs). An LIN is a generalized multistage interconnection network commonly used in reconfigurable systems; the nets (links) are arranged in sets (referred to as layers) of different size. Switching elements (made of simple switches such as transmission-gate-like devices) are arranged in a cascade to connect pairs of layers. The switching elements of an LIN have the same number of switches, but the switching patterns may not be uniform. A comprehensive fault model for the nets and switches is assumed at physical and behavioral levels. Testing requires configuring the LIN …

Go to article

Structural And Magnetic Properties Of Mrsr₂Y₁.₅Ce₀.₅Cu₂Oz (M-1222) Compounds With M = Fe And Co, V. P. S. Awana, Anurag Gupta, H. Kishan, Satish K. Malik, William B. Yelon, J. Lindén, M. Karppinen, H. Yamauchi, Darshan C. Kundaliya Jun 2004

Structural And Magnetic Properties Of Mrsr₂Y₁.₅Ce₀.₅Cu₂Oz (M-1222) Compounds With M = Fe And Co, V. P. S. Awana, Anurag Gupta, H. Kishan, Satish K. Malik, William B. Yelon, J. Lindén, M. Karppinen, H. Yamauchi, Darshan C. Kundaliya

Physics Faculty Research & Creative Works

The MSr2Y1.5Ce0.5Cu2Oz (M-1222) compounds, with M = Fe and Co, have been synthesized through a solid-state reaction route. Both compounds crystallize in a tetragonal structure (space group 14/mmm). A Rietveld structural refinement of the room-temperature neutron diffraction data for Fe-1222 reveals that nearly half the Fe remains at the M site, while the other half goes to the Cu site in the CuO2 planes. Existence of Fe at two different lattice sites is also confirmed by 57Fe Mössbauer spectroscopy from which it is inferred that ~50% of the total Fe occupies the Cu site in the CuO2 planes as Fe3+, …

Go to article

Pulse Regulation Control Technique For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Curtis Davis Jun 2004

Pulse Regulation Control Technique For Bifred Converter, Mehdi Ferdowsi, Ali Emadi, Mark Telefus, Curtis Davis

Electrical and Computer Engineering Faculty Research & Creative Works

Pulse Regulation control scheme is presented and applied to BIFRED converter operating in discontinuous conduction mode (DCM). In contrast to the conventional control techniques, the principal idea of Pulse Regulation is to regulate the output voltage using a series of high and low power pulses generated by the current of the input inductor. In this paper, analysis of BIFRED converter operating in DCM is presented. The basic idea of Pulse Regulation as well as the estimation of the output voltage ripple is introduced. Experimental results on a prototype converter are also demonstrated.

Go to article

Issues With Low-Input-Voltage Boost Converter Design, Jonathan W. Kimball, Theresa L. Flowers, Patrick L. Chapman Jun 2004

Issues With Low-Input-Voltage Boost Converter Design, Jonathan W. Kimball, Theresa L. Flowers, Patrick L. Chapman

Electrical and Computer Engineering Faculty Research & Creative Works

This paper addresses boost converter circuits that are built for very low input voltages, i.e. less than 1 V. Such circuits can be useful for single-cell solar and fuel cell power supplies. Important issues are physical size, high conversion ratio, efficiency, and startup. Several experimental studies show the impact of these issues. A startup technique is proposed that works for arbitrarily low input voltages.

Go to article

Image Analysis Techniques For The Automated Evaluation Of Subaxial Subluxation In Cervical Spine X-Ray Images, R. Joe Stanley, Santosh Seetharaman, L. Rodney Long, Sameer K. Antani, George R. Thoma, Edward Downey Jun 2004

Image Analysis Techniques For The Automated Evaluation Of Subaxial Subluxation In Cervical Spine X-Ray Images, R. Joe Stanley, Santosh Seetharaman, L. Rodney Long, Sameer K. Antani, George R. Thoma, Edward Downey

Electrical and Computer Engineering Faculty Research & Creative Works

Rheumatoid arthritis is a chronic inflammatory disease affecting synovial joints of the body, especially the hands and feet, spine, knees and hips. For many patients, the cervical spine is associated with rheumatoid arthritis. Subluxation is the abnormal movement of one of the bones that comprise a joint. In this research, image analysis techniques have been investigated for the recognition of cervical spine x-ray images with one or more instances of subaxial subluxation. Receiver operating characteristic curve results are presented, showing potential for subaxial subluxation discrimination on an image-by-image basis.

Go to article

Autonomous Control Of A Scale Model Of A Trailer-Truck Using An Obstacle-Avoidance Path-Planning Hierarchy, Robert S. Woodley, Levent Acar Jun 2004

Autonomous Control Of A Scale Model Of A Trailer-Truck Using An Obstacle-Avoidance Path-Planning Hierarchy, Robert S. Woodley, Levent Acar

Electrical and Computer Engineering Faculty Research & Creative Works

A scale model of a tractor-trailer truck was developed as a testbed for control algorithms. The truck operates in autonomous or semi-autonomous modes. An on-board Pentium computer with a PC104 bus performs the computations and data collection. Various sensors and a wireless transceiver are on-board the truck. Our research focus has been in the autonomous control of vehicles using intelligent systems. For this document we have employed a multi-resolutional hierarchy to plan a path for the tractor-trailer truck. The hierarchy starts with a simple path then warps it around obstacles. The modular construction of the hierarchy allows more intelligent agents …

Go to article

The Influence Of Strontium Substitution In Fluorapatite Glasses And Glass-Ceramics, R. G. Hill, A. Stamboulis, R. V. Law, A. Clifford, Mark R. Towler, C. Crowley May 2004

The Influence Of Strontium Substitution In Fluorapatite Glasses And Glass-Ceramics, R. G. Hill, A. Stamboulis, R. V. Law, A. Clifford, Mark R. Towler, C. Crowley

Chemical and Biochemical Engineering Faculty Research & Creative Works

Strontium is often substituted for calcium in order to confer radio-opacity in glasses used for dental cements, Biocomposites and bio glass-ceramics. The present paper investigates the influence of substituting strontium for calcium in a glass of the following composition: 4.5SiO23Al2O 31.5P2O53CaO2CaF2, having a Ca:P ratio of 1.67 corresponding to calcium fluorapatite (Ca5(PO 4)3F). The glasses were characterized by magic angle spinning nuclear magnetic resonance (MAS-NMR), by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The 29Si, 27Al and 31P NMR spectra for the glasses with …

Go to article

Characterisation Of The Glass Fraction Of A Selection Of European Coal Fly Ashes, J. Henry, Mark R. Towler, K. T. Stanton, X. Querol, N. Moreno May 2004

Characterisation Of The Glass Fraction Of A Selection Of European Coal Fly Ashes, J. Henry, Mark R. Towler, K. T. Stanton, X. Querol, N. Moreno

Chemical and Biochemical Engineering Faculty Research & Creative Works

Fly ash largely consists of the inorganic content of coal that remains after combustion. The crystalline phases present in fly ash may form upon cooling of a molten alumino-silicate glass. This view is supported by the spherical shape of many fly ash particles, inferring that they have gone through a viscous fluid state. The amorphous content in fly ash is believed to dominate reactivity behaviour, under both alkaline and acid conditions, because glasses have a higher potential energy than the equivalent crystal structure and the variation of bond angles and distances in a glass makes the bond breakage easier. It …

Go to article

First Prev Next Last