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Articles 2641 - 2670 of 2820

Full-Text Articles in Engineering

Instantaneously Trained Neural Networks With Complex Inputs, Pritam Rajagopal Jan 2003

Instantaneously Trained Neural Networks With Complex Inputs, Pritam Rajagopal

LSU Master's Theses

Neural network architectures that can handle complex inputs, such as backpropagation networks, perceptrons or generalized Hopfield networks, require a large amount of time and resources for the training process. This thesis adapts the time-efficient corner classification approach to train feedforward neural networks to handle complex inputs using prescriptive learning, where the network weights are assigned simply upon examining the inputs. At first a straightforward generalization of the CC4 corner classification algorithm is presented to highlight issues in training complex neural networks. This algorithm performs poorly in a pattern classification experiment and for it to perform well some inputs have to …

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Analysis Of Laboratory And Field Pull-Out Tests Of Geosynthetics In Clayey Soils, Ather Mohiuddin Jan 2003

Analysis Of Laboratory And Field Pull-Out Tests Of Geosynthetics In Clayey Soils, Ather Mohiuddin

LSU Master's Theses

Soil reinforcement interaction is a key issue in the design of reinforced soil structures. Therefore, it is important to analyze the pull-out mechanism, and to evaluate the interaction between the soil and geosynthetic reinforcement. Majority of pull-out tests performed to date were in granular soils, and very few tests were reported in cohesive soils. The shortage of in-situ granular materials and the availability of cohesive soils in Louisiana have initiated a growing interest in using the marginal soils as backfill material. To investigate the soil-geosynthetic interaction parameters, series of laboratory and field pull-out tests were conducted using various geosynthetics (geogrids: …

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Axis-Switching In Square Coaxial Jets, Victor Piffaut Jan 2003

Axis-Switching In Square Coaxial Jets, Victor Piffaut

LSU Master's Theses

Airflow from single and coaxial contoured nozzles with a square cross section is studied using constant temperature anemometry. The inner to outer jet velocity ratio is 1.5. The Reynolds number of the outer jet based on the hydraulic diameter of the outer nozzle exit is 15,300. Results are compared to previous data obtained with circular nozzles under the same conditions. Properties of the jets and their shear layers such as turbulence shear layer thicknesses and growth rates were derived from the velocity record. The mixing between the jets and with the external flow was found to be enhanced by passive …

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Effect Of Jet Hole Arrays Arrangement On Impingement Heat Transfer, Lujia Gao Jan 2003

Effect Of Jet Hole Arrays Arrangement On Impingement Heat Transfer, Lujia Gao

LSU Master's Theses

A comprehensive investigation on impingement heat transfer of different jet array arrangements is presented. Experiments on the inline jet arrays and the linearly stretched arrays are performed using transient liquid crystal technique. Three experimented basic inline jet arrays are configurations 4X4, 8X4 and 8X8. Two experimented cases for the linearly stretched arrays are the uniform diameter case and the varying diameter case. For the inline jet arrays, three jet heights Z/D=1, 3 and 5 and three Reynolds numbers Re=5000, 10000 and 15000 are investigated. For linearly stretched arrays, the same three jet heights and Re=2000, 6000 and 10000 are investigated. …

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Denoising Techniques - A Comparison, Sarita Veera Dangeti Jan 2003

Denoising Techniques - A Comparison, Sarita Veera Dangeti

LSU Master's Theses

Visual information transmitted in the form of digital images is becoming a major method of communication in the modern age, but the image obtained after transmission is often corrupted with noise. The received image needs processing before it can be used in applications. Image denoising involves the manipulation of the image data to produce a visually high quality image. This thesis reviews the existing denoising algorithms, such as filtering approach, wavelet based approach, and multifractal approach, and performs their comparative study. Different noise models including additive and multiplicative types are used. They include Gaussian noise, salt and pepper noise, speckle …

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Traffic Engineering In Multiprotocol Label Switching Networks, Chung-Yu Wei Jan 2003

Traffic Engineering In Multiprotocol Label Switching Networks, Chung-Yu Wei

LSU Master's Theses

The goal of Traffic Engineering is to optimize the resource utilization and increase the network performance. Constraint-based routing has been proposed as an networks effective approach to implement traffic engineering in Multiprotocol Label Switching. In this thesis, we review several algorithms on constraint-based routing from the literature and point out their advantages and disadvantages. We then propose several algorithms to overcome some of the shortcomings of these approaches. Our algorithms are specifically suitable for large densely connected networks supporting both Quality of Service traffic and the Best Effort traffic. In large networks the size of the MPLS label space in …

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Evaluation Of Mechanical Fitness For Service Of High Temperature Hydrogen Attacked Steels, Brent Matthew Saba Jan 2003

Evaluation Of Mechanical Fitness For Service Of High Temperature Hydrogen Attacked Steels, Brent Matthew Saba

LSU Master's Theses

A novel approach is introduced in evaluating one of industry’s most complex corrosion phenomena, high temperature hydrogen attack (HTHA). Limited efforts have been made by industry to address this degradation mechanism and even less data are available to properly utilize their evaluation techniques. The predominant fracture mechanics based analysis of HTHA relies on Charpy V-Notch (CVN) impact test data. In the face of limited CVN test data, accurate results are shaky at best. The HTHA evaluation set forth in this paper combines the analysis tools of plastic collapse and both static and dynamic fracture mechanics. The first condition addresses plastic …

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Effect Of Unsteady Wake, Free Stream Turbulence, Tip Geometry On Blade Tip Flow And Heat Transfer, Vikrant Saxena Jan 2003

Effect Of Unsteady Wake, Free Stream Turbulence, Tip Geometry On Blade Tip Flow And Heat Transfer, Vikrant Saxena

LSU Master's Theses

A comprehensive investigation of the effect of various tip sealing geometries is presented on the blade tip leakage flow and associated heat transfer. The linear cascade is made of four blades scaled up HPT turbine in a low speed wind tunnel facility with the two corner blades acting as guides. The tip section of a HPT first stage rotor blade is used to fabricate the 2-D blade. The wind tunnel accommodates an 116 degree turn in the flow through the blade cascade. The mainstream Reynolds number based on the axial chord length at cascade exit is 4.83e5. The center blade …

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Adsorption Of Aromatic Hydrocarbons At Gas-Water Interface, Suresh Raja Jan 2003

Adsorption Of Aromatic Hydrocarbons At Gas-Water Interface, Suresh Raja

LSU Master's Theses

Adsorption of organic vapors at a gas-water interface has several physical applications with respect to natural processes in the environment. Understanding the adsorption processes is critical in development of risk assessment and modeling of transport and fate of various chemical species that are abundantly present in the environment. Evidences from the works of several researchers point out deviations in gas-liquid partitioning as predicted by Henry’s law. In view of several theories that describe these deviations, adsorption process is hypothesized to be significant in gas-liquid partitioning, in addition to temperature and presence of organic matter, particularly on liquid surfaces with high …

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An Experimental Study Of The Applicability Of Flooding Phenomena To The Dynamic Lubrication Method Of Well Control, Rishi R. Ramtahal Jan 2003

An Experimental Study Of The Applicability Of Flooding Phenomena To The Dynamic Lubrication Method Of Well Control, Rishi R. Ramtahal

LSU Master's Theses

This research investigates the feasibility of the dynamic lubrication method of well control as an alternative to conventional stepwise lubrication. The applicability of flooding phenomena to dynamic lubrication and its use in an optimization method to maximize pumping rates was also investigated. An experimental approach was taken in which experiments were conducted in a 13’ long laboratory apparatus designed to emulate the geometry in a wellhead and also in a full-scale research well. The laboratory experiments were conducted to visually investigate the mechanism of flooding and derive a flooding correlation applicable to this type of system. The full-scale experiments were …

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Predictions For Multi-Scale Shock Heating Of A Granular Energetic Material, Venugopal Jogi Jan 2003

Predictions For Multi-Scale Shock Heating Of A Granular Energetic Material, Venugopal Jogi

LSU Master's Theses

This thesis addresses the multi scale heating of a granular energetic solid due to shock loading. To this end, an existing mathematical model that has been used to predict low pressure bulk and localized heating of the granular high-explosive HMX ([CH2NNO2]4) is extended to account for compressibility and melting of the pure phase solid. Dense granular HMX has a heterogeneous structure composed of randomly packed small grains (average size ~ 100 µm) having a free-pour density that is approximately 65% of the pure phase solid density. The shock loading response of this material is …

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Application Of Mechanistic Models In Predicting Flow Behavior In Deviated Wells Under Ubd Conditions, Faisal Abdullah Aladwani Jan 2003

Application Of Mechanistic Models In Predicting Flow Behavior In Deviated Wells Under Ubd Conditions, Faisal Abdullah Aladwani

LSU Master's Theses

Underbalanced drilling (UBD) has increased in recent years because of the many advantages associated with it. These include increase in the rate of penetration and reduction of lost circulation and formation damage. Drilling of deviated and horizontal wells also increased since recovery can be improved from a horizontal or a deviated well. The drilling of deviated wells using UBD method will reduce several drilling related problems such as hole cleaning and formation damage. Prediction of flow and pressure profiles while drilling underbalanced in such wells will help in designing and planning of the well. The main aim of this research …

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Efficient Embedding Of Virtual Hypercubes In Irregular Wdm Optical Networks, Guru Prasad P. Kithlanagamangala Jan 2003

Efficient Embedding Of Virtual Hypercubes In Irregular Wdm Optical Networks, Guru Prasad P. Kithlanagamangala

LSU Master's Theses

This thesis addresses one of the important issues in designing future WDM optical networks. Such networks are expected to employ an all-optical control plane for dissemination of network state information. It has recently been suggested that an efficient control plane will require non-blocking communication infrastructure and routing techniques. However, the irregular nature of most WDM networks does not lend itself to efficient non-blocking communications. It has been recently shown that hypercubes offer some very efficient non-blocking solutions for, all-to-all broadcast operations, which would be very attractive for control plane implementation. Such results can be utilized by embedding virtual structures in …

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Arithmetic Logic Unit (Alu) Design Using Reconfigurable Cmos Logic, Chandra Srinivasan Jan 2003

Arithmetic Logic Unit (Alu) Design Using Reconfigurable Cmos Logic, Chandra Srinivasan

LSU Master's Theses

Using the reconfigurable logic of multi-input floating gate MOSFETs, a 4-bit ALU has been designed for 3V operation. The ALU can perform four arithmetic and four logical operations. Multi- input floating gate (MIFG) transistors have been promising in realizing increased functionality on a chip. A multi- input floating gate MOS transistor accepts multiple inputs signals, calculates the weighted sum of all input signals and then controls the ON and OFF states of the transistor. This enhances the transistor function to more than just switching. This changes the way a logic function can be realized. Implementing a design using multi-input floating …

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Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi Jan 2003

Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi

LSU Master's Theses

In this study, heat transfer coefficient and film effectiveness distributions are investigated for a film cooling hole configuration that has inclined holes discharging into a tangential slot before interactions with the mainstream. The cylindrical holes are inclined 35° along the mainstream direction. The effect of coolant-to-mainstream blowing ratio is examined for M=0.5 and M=1.0. Different slot width to hole ratios and also the effect of hole exit condition (square edge and triangular edge) is considered. The mainstream velocity and free-stream turbulence intensity in the low speed wind tunnel are 9 m/s and 7% respectively and the mainstream Reynolds number based …

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Dechlorination Of 1,2,3,4-Tetrachlorobenzene In Organic Matter- And Mineral-Dominated Soils And Effects Of Typha Latifolia Roots, Lizhu Lin Jan 2003

Dechlorination Of 1,2,3,4-Tetrachlorobenzene In Organic Matter- And Mineral-Dominated Soils And Effects Of Typha Latifolia Roots, Lizhu Lin

LSU Master's Theses

A variety of environments are contaminated with chlorinated benzenes. Therefore, investigating the biodegradation of chlorobenzenes in different types of soils is useful in assessing the feasibility of bioremediation. One mineral-dominated soil: PPI (Petro Processors Inc. site) soil, and three organic matter-dominated soils (natural wetland soil, constructed wetland soil (a mixture of peat, compost and sand), and river sediment) were used to investigate anaerobic biodegradation of 1,2,3,4-Tetrachlorobenzene (1,2,3,4-TeCB) using laboratory microcosms. To determine whether methanogens were directly responsible for dechlorination, a comparative study using 2-bromoethanesulfonic acid (BES) for inhibition of methanogenesis was conducted. Hydrogen and methane concentrations, and microbial diversities were …

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Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta Jan 2003

Synthesis, Structure And Properties Of Nanolayered Dlc/Dlc Films, Pankaj Gupta

LSU Master's Theses

Diamondlike carbon (DLC) films have been explored extensively in the past due to their highly attractive properties. However, the high level of internal stress developed during growth prevents deposition of thick films. Synthesis of DLC/DLC multilayers (DDM) presents a venue to overcome this drawback. In the present study, DLC films and DDM were deposited on Si substrate using dc plasma of CH4 and Ar gas mixture. FTIR was used to analyze the structure of the DLC films. Mechanical properties of the films were characterized by microhardness testing and nanoindentation. The tribological properties were studied by conducting pin-on-disc experiments in …

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High Strain Rate Properties Of Polymer Matrix Composites, Amol Jadhav Jan 2003

High Strain Rate Properties Of Polymer Matrix Composites, Amol Jadhav

LSU Master's Theses

The vast differences in strength, ultimate strain and modulus during high strain rate (HSR) deformation of materials have been a very long-standing subject of engineering interest. This thesis deals with characterization of mechanical properties of two composite materials, balanced angle-ply graphite epoxy laminates (fibrous composite) and syntactic foams (particulate composite). The focus of this study is to compare the mechanical properties of these composite materials at high strain rates and quasi-static conditions and to find out the effects of failure modes on HSR mechanical properties of these materials. Split Hopkinson Pressure Bar (SHPB) apparatus is used for the HSR testing …

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Exploring Geometric, Kinematic And Behavioral Scalability Of Microscopic Traffic Simulation Systems, Srikanth Chakravarthy Jan 2003

Exploring Geometric, Kinematic And Behavioral Scalability Of Microscopic Traffic Simulation Systems, Srikanth Chakravarthy

LSU Master's Theses

Even with today's remarkable advancement in computing power, microscopic simulation modeling remains a computationally intensive process that imposes limitations on its potential use for modeling large-scale transportation networks. Research and practice have repeatedly demonstrated that microscopic simulation runs can be excessively time-consuming, depending on the network size, the number of simulated entities (vehicles), and the computational resources available. While microscopic features of a simulated system collectively define the overall system characteristics, it is argued that the microscopic simulation process itself is not necessarily free of redundancy, which if reduced, could substantially improve the computational efficiency of simulation systems without compromising …

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Transmission Of Electromagnetic Power Through A Biological Medium, Ripan Das Jan 2003

Transmission Of Electromagnetic Power Through A Biological Medium, Ripan Das

LSU Master's Theses

Primary goal of this work is to study transmission of EM power through a multilayered biological medium. For a particular case study, EM power transmission from an external transmitter to a coupled receiver implanted inside a biological medium simulating a human body is studied to find solutions for factors such as optimum transmission frequency and excitation current. Different aspects of interaction of EM waves with biological bodies and tissues are discussed. Two major factors that may affect transmission of EM power through a biological body are absorption and reflection of EM waves. A simulation in which exact Maxwell's equations are …

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Laboratory Evaluation Of In-Situ Tests As Potential Quality Control/Quality Assurance Tools, Ekrem Seyman Jan 2003

Laboratory Evaluation Of In-Situ Tests As Potential Quality Control/Quality Assurance Tools, Ekrem Seyman

LSU Master's Theses

There are new in-situ test devices such as the Geogauge, Light Falling Weight Deflectometer (LFWD) and Dynamic Cone Penetrometer (DCP). Unlike the nuclear density gauge, the new methods provide measurements based on the engineering properties (strength/stiffness) of soil instead of physical properties like field density and moisture content. However the geogauge, LFWD and the DCP are not yet proven to be reliable and the correlations of these tests with standard tests are limited. An extensive laboratory investigation was carried out to evaluate the Geogauge, LFWD and DCP as potential tests to measure in-situ stiffness of highway materials and embankments. In …

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Wind Loads On Multiple Cylinders Arranged In Tandem With Effects Of Turbulence And Surface Roughness, Xianzhi Liu Jan 2003

Wind Loads On Multiple Cylinders Arranged In Tandem With Effects Of Turbulence And Surface Roughness, Xianzhi Liu

LSU Master's Theses

The goal of this study is to investigate the characteristics of mean drag and lift forces for a series of cylinders arranged in tandem with varying flow turbulence and surface roughness. This goal was fulfilled by building a wind tunnel test section capable of generating both smooth flow and turbulent flow, and by adopting cylinder models with certain types of surface roughness as well as the smooth surface. In both smooth flow and grid-turbulence flow conditions, single cylinders as well as multiple cylinders were tested. The tested Reynolds number ranged from 2.7×104 to 8.6×104. For multiple-cylinder tests, a majority of …

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Computational Model For Heat Transfer In The Human Eye Using The Finite Element Method, Umit Cicekli Jan 2003

Computational Model For Heat Transfer In The Human Eye Using The Finite Element Method, Umit Cicekli

LSU Master's Theses

In this work a finite element model for the human eye presented. Thermal analysis was done in order to capture the temperature variation in the human eye. The model was created using advance finite element program ABAQUS. In the model each of the eye's component (cornea, sclera, lens, iris, aqueous and vitreous humor) has own material property. Specific boundary conditions were used for the model. The model incorporates the interaction between eyes components. The Comparisons were done with the available experimental results. The results show that there is a temperature variation in the human eye components with the increasing the …

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Numerical Solution Of Ocular Fluid Dynamics, Satish Kumar Jan 2003

Numerical Solution Of Ocular Fluid Dynamics, Satish Kumar

LSU Master's Theses

Numerical calculations of the aqueous humor dynamics in the anterior chamber of both the rabbit and the human eye are presented to delineate the basic flow and transport mechanisms. The calculations are based on a geometrical model of the eye, which represents the Trabecular mesh (TM) as a multi-layered porous zone of specified pore sizes and void fraction. Buoyancy is observed to be the dominant driving mechanism for the convective motion in both orientations (horizontal and vertical) of the eye. Reducing the TM pore size does not appear to have a significant influence on the intra-ocular pressure (IOP) until the …

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Iddq Testing Of A Cmos 10-Bit Charge Scaling Digital-To-Analog Converter, Srinivas Rao Aluri Jan 2003

Iddq Testing Of A Cmos 10-Bit Charge Scaling Digital-To-Analog Converter, Srinivas Rao Aluri

LSU Master's Theses

This work presents an effective built-in current sensor (BICS), which has a very small impact on the performance of the circuit under test (CUT). The proposed BICS works in two-modes the normal mode and the test mode. In the normal mode the BICS is isolated from the CUT due to which there is no performance degradation of the CUT. In the testing mode, our BICS detects the abnormal current caused by permanent manufacturing defects. Further more our BICS can also distinguish the type of defect induced (Gate-source short, source-drain short and drain-gate short). Our BICS requires neither an external voltage …

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Investigation Of Qualitative Methods For Diagnosis Of Poor Bit Performance Using Surface Drilling Parameters, Arash Aghassi Jan 2003

Investigation Of Qualitative Methods For Diagnosis Of Poor Bit Performance Using Surface Drilling Parameters, Arash Aghassi

LSU Master's Theses

Bit performance in deep shale when using water-based mud is typically poor. This study is part of a larger research project to improve that performance entitled "Automated Rig Controls for Improved Drilling Costs." The objective of the project is diagnosis of changes in drill bit performance to provide a logical basis for automating draw works control, maximizing bit performance, and reducing drilling costs. The specific goal of this study is a means to diagnose bit performance, specifically to identify bit balling and lithology changes, using real-time drilling data. The research began by identifying symptoms relating to specific causes of bit …

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Remote Power Delivery And Signal Amplification For Mems Applications, Sunitha Kopparthi Jan 2003

Remote Power Delivery And Signal Amplification For Mems Applications, Sunitha Kopparthi

LSU Master's Theses

Device such as remotely located sensors and bio-implanted devices such as gastric pacer require power for operation. The most commonly used energy source for such devices is a battery cell included in the receiver capsule. Wires can also be used with an external power source but in some applications have serious limitations. This work examines a wireless power transmitter and receiver system to provide power to a remotely located microsystem. Inductive power coupling is the method of choice. For gastric pacer application, external transmitter coil can be worn around the waist as a belt and the receiver coil can be …

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Blind Fault Detection Using Spectral Signatures, Pallavi Chethan Jan 2003

Blind Fault Detection Using Spectral Signatures, Pallavi Chethan

LSU Master's Theses

This work studies a blind fault detection method, which only analyses a system's output signal for any change in the characteristics from pre-fault to post-fault to identify the occurrence of faults. In our case the fault considered to develop the procedure is change in time constant of an aircraft's aileron-actuator system and its simplified version - a position servo system. The method is studied as an alternative to conventional fault detection and identification methods. The output signal is passed through a filter bank to enhance the effect of a fault. The Short time Fourier transform is performed on the enhanced …

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Tensile Strength And Bonding Characteristics Of Self-Compacting Concrete, Cristian Druta Jan 2003

Tensile Strength And Bonding Characteristics Of Self-Compacting Concrete, Cristian Druta

LSU Master's Theses

Self-compacting concrete, also referred to as self-consolidating concrete, is able to flow and consolidate under its own weight and is deaerated almost completely while flowing in the formwork. It is cohesive enough to fill the spaces of almost any size and shape without segregation or bleeding. This makes SCC particularly useful wherever placing is difficult, such as in heavily-reinforced concrete members or in complicated workforms. The objectives of this research were to compare the Splitting Tensile Strength and Compressive Strength values of self-compacting and normal concrete specimens and to examine the bonding between the coarse aggregate and the cement paste …

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The Transcendental Eigenvalue Problem And Its Application In System Identification, Kumar Vikram Singh Jan 2003

The Transcendental Eigenvalue Problem And Its Application In System Identification, Kumar Vikram Singh

LSU Doctoral Dissertations

An accurate mathematical model is needed to solve direct and inverse problems related to engineering analysis and design. Inverse problems of identifying the physical parameters of a non-uniform continuous system based on the spectral data are still unsolved. Traditional methods, for the system identification purpose, describe the continuous structure by a certain discrete model. In dynamic analysis, finite element or finite difference approximation methods are frequently used and they lead to an algebraic eigenvalue problem. The characteristic equation associated with the algebraic eigenvalue problem is a polynomial. Whereas, the spectral characteristic of a continuous system is represented by certain transcendental …

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