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2011

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Articles 4771 - 4800 of 5801

Full-Text Articles in Engineering

Evaluation Of The Orientation Of 90⁰ And 180⁰ Reinforcing Bar Hooks, Nichole Lynn Podhorsky Jan 2011

Evaluation Of The Orientation Of 90⁰ And 180⁰ Reinforcing Bar Hooks, Nichole Lynn Podhorsky

Masters Theses

"This thesis describes test results of a study initiated to evaluate the potential influence of hook tilt angle of standard reinforcing hooks on the bond strength of concrete. The topic of the evaluation of the orientation of 90 and 180 degree reinforcing bar hooks in concrete members was identified by the Concrete Reinforcing Steel Institute (CRSI) as high-priority for the reinforcing steel industry. In this test program, a series of single bar and multiple bar specimens were designed and tested to examine bar behavior and potential group effects that may exist in wide flexural members with multiple bars, such as …

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Impact Effects Of Explosively Formed Projectiles On Normal And High Strength Concrete, Laurin Ashley Bookout Jan 2011

Impact Effects Of Explosively Formed Projectiles On Normal And High Strength Concrete, Laurin Ashley Bookout

Masters Theses

"The ability to quickly estimate the damage that a projectile will do to a structure is highly desired for structures that will be required to resist threats of this nature. There are several formulas for concrete penetration due to projectile impact that are based on empirical data. However, there is a lack of publicly available data for projectile impacts with striking velocities that exceed 1 km/s and have weights greater than a few grams. This research is intended to expand the available data on explosively formed projectile impacts and determine which, if any, of the existing equations can be used …

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Trait Approach To Leadership In Campus Organizations: The Hogan Personality Inventory As A Predictor, Christyn Nicolle Collum Jan 2011

Trait Approach To Leadership In Campus Organizations: The Hogan Personality Inventory As A Predictor, Christyn Nicolle Collum

Masters Theses

"The trait approach to leadership has been researched extensively and applied to several fields. This study examined whether or not student leadership in registered student organizations is related to personality traits on the Missouri University of Science and Technology campus from spring semesters 2008, 2009, and 2010. It also explored whether or not traits are related to students joining organizations, during these same semesters. The students' personalities were evaluated using the Hogan Personality Inventory (HPJ), which entering freshmen voluntarily completed. The seven scales of the HPJ are Adjustment, Ambition, Sociability, Interpersonal Sensitivity, Prudence, Inquisitiveness, and Learning Approach. Personality results were …

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Microcontroller-Based Multiple-Input Multiple-Output Transmitter Systems, Balaji Madapuci Kanday Jan 2011

Microcontroller-Based Multiple-Input Multiple-Output Transmitter Systems, Balaji Madapuci Kanday

Masters Theses

"Multiple-Input Multiple_output (MIMO) Systems use multiple antennas at both the transmitter and receiver to increase data throughput and/or system reliability. An MIMO transmitter can be implemented using a variety of approaches. This work describes some of the approaches that can be used to generate the transmitted waveforms, and discuss the features and limitation of each. In particular, it shows haw a microcontroller-based system can be used for applications which require low power consumption. This thesis also describes the high-level design of a microcontroller-based MIMO transmitter. The computational speed of the microcontroller, as compared to Field-programmable Gate Array (FPGA) and Digital …

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Characterizing Formation Dredgeability For Clamshell Dredge, Bismark Osei Jan 2011

Characterizing Formation Dredgeability For Clamshell Dredge, Bismark Osei

Masters Theses

"The lack of metrics to assess clamshell dredge formation dredgeability limits the ability of engineers to predict the dredgeability of compact material and increases the risks associated with clamshell selection. Research is, therefore, necessary to increase our understanding of clamshell dredgeability assessment by evaluating possible metrics that will allow the operator to select the optimal clamshell for the operation. Work done and motor energy are possible dredgeability metrics that can be estimated using micro-processor based machine monitoring. The objective of this work is to test the hypotheses that: (i) work done by the pistons during dredging, by a hydraulically actuated …

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Risk-Sensitive Preventive Maintenance Policies Using Semivariance, Venkata Manojramam Tirumalasetty Jan 2011

Risk-Sensitive Preventive Maintenance Policies Using Semivariance, Venkata Manojramam Tirumalasetty

Masters Theses

"Preventive maintenance is an important tool that increases the reliability of the production system by reducing downtime due to failures. In the literature, maintenance and replacement policies for productions systems have been widely studied and modeled. Traditionally preventive maintenance has focused only on minimizing expected costs without considering variability in costs. Cost variability is also commonly known as risk. In a 2003 paper, Chen and Jin used variance of costs as a measure of risk for formulating preventive maintenance policies. The variance criterion that they used ignored the probability of costs exceeding monthly or yearly budgets provided to managers. The …

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Integrated Reliable And Robust Design, Gowrishankar Ravichandran Jan 2011

Integrated Reliable And Robust Design, Gowrishankar Ravichandran

Masters Theses

"The objective of this research is to develop an integrated design methodology for reliability and robustness. Reliability-based design (RBD) and robust design (RD) are important to obtain optimal design characterized by low probability of failure and minimum performance variations respectively. But performing both RBD and RD in a product design may be conflicting and time consuming. An integrated design model is needed to achieve both reliability and robustness simultaneously. The purpose of this thesis is to integrate reliability and robustness. To achieve this objective, we first study the general relationship between reliability and robustness. Then we perform a numerical study …

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Design Of A Conditioner For Smoothing Wind Turbine Output Power, Murali Bottu Jan 2011

Design Of A Conditioner For Smoothing Wind Turbine Output Power, Murali Bottu

Masters Theses

"As a result of wind speed intermittency, wind turbine output power can be highly variable. The large variability in output power can adversely impact local loads that are sensitive to pulsating power. To mitigate large swings in power, the wind turbine output power can be smoothed by using a small energy buffer. A power conditioner is proposed to smooth the wind power output by utilizing the energy of an ultracapacitor. The conditioner is based on a single phase voltage source inverter (VSI) connected between the grid interconnection point and the ultracapacitor. The shunt VSI injects or absorbs active power from …

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Multiple-Input Multiple-Output System Simulation For Spinning Vehicles, Samuel James Petersen Jan 2011

Multiple-Input Multiple-Output System Simulation For Spinning Vehicles, Samuel James Petersen

Masters Theses

"This paper investigates the performance of a multiple-input multiple-output (MIMO) wireless communication system, when the transmitter is located on a spinning vehicle. In particular, a 2x2 MIMO system is used, with Alamouti coding at the transmitter. Both Rayleigh and Rician statistical models are considered in this paper and are combined with a deterministic spinning model to simulate the channel. The spinning of the transmitting vehicle, relative to the stationary receive antennas causes additional signal fading, and complicates the decoding and channel estimation. The simulated bit error rate is the primary performance metric used. A 4x2 asymmetric Alamouti coding scheme is …

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Ozone Uptake Rates And Secondary Product Emissions Of Green Building Materials, Seth Paul Lamble Jan 2011

Ozone Uptake Rates And Secondary Product Emissions Of Green Building Materials, Seth Paul Lamble

Masters Theses

"Building materials considered "green" were tested for their ability to remove ozone and their potential to generate undesirable byproducts such as aldehydes. Three types of ceiling tile were tested, along with seven flooring materials and eight wall materials. These materials were selected based on "green" criteria. For several this means they were recycled or produced from renewable resources. Others were designed to be low emitting, or due to their composition were likely to be low emitting. Ozone deposition velocities ranged from 0.25 m h-1 for a type of resilient linoleum type flooring to 8.23 m h-1 for a clay based …

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Installation And Performance Evaluation Of Coaxial Cable Sensors For Crack And Corrosion Detection, Iana Muchaidze Jan 2011

Installation And Performance Evaluation Of Coaxial Cable Sensors For Crack And Corrosion Detection, Iana Muchaidze

Masters Theses

"Even under service loads, reinforced concrete (RC) structures can develop cracks that result in excessive deflection of the structures and provide passages for moisture to corrode steel reinforcement. It is thus critical to develop a simple, cost-effective tool for real-time crack monitoring and associated corrosion detection that may affect the engineering maintenance of RC structures. The objectives of this study include: (1) to develop a die-cut manufacturing process of coaxial cables with spiral outer conductors, (2) to quantify the sensing properties of a miniaturized topology-based crack sensor, (3) to investigate the effectiveness of various sensor installation procedures in RC applications, …

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Bond Strength Of High-Volume Fly Ash Concrete, Michael Hayse Wolfe Jan 2011

Bond Strength Of High-Volume Fly Ash Concrete, Michael Hayse Wolfe

Masters Theses

"Concrete is the most consumed man-made material in the world. Unfortunately, due to the production of cement, concrete has a large carbon footprint. Replacement of cement with fly ash, an industrial waste product, offers a sustainable alternative. The goal of this research was to explore the feasibility of using high-volume fly ash (HVFA) concrete for structural applications by testing the material's reinforcement bond properties. A series of pull-out tests and beam splice tests were performed on specimens with a 70 percent fly ash replacement of cement and then compared to identical tests performed on control specimens cast from a 100 …

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Impact Of Combustion Phasing On Energy And Availability Distributions Of An Internal Combustion Engine, Shawn Nicholas Wildhaber Jan 2011

Impact Of Combustion Phasing On Energy And Availability Distributions Of An Internal Combustion Engine, Shawn Nicholas Wildhaber

Masters Theses

"High fuel efficiency has become an extremely desirable trait for internal combustion engines. This motivation has driven extensive research on methods to improve fuel efficiency on engines of various sizes. Many of these methods involve changes to the properties of the combustion process. One way to induce these property changes is through varying the phasing of combustion. Combustion phasing can be defined as the time in the engine cycle, specifically the compression and expansion strokes, where combustion occurs. A change in combustion phasing causes a change in combustion duration. The duration of combustion impacts how the energy and work potential …

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Simulation Of The Field Electron Emission Characteristics Of A Flat Panel X-Ray Source, Chrystian Mauricio Posada ArbeláEz Jan 2011

Simulation Of The Field Electron Emission Characteristics Of A Flat Panel X-Ray Source, Chrystian Mauricio Posada ArbeláEz

Masters Theses

"A distributed flat panel x-ray source is designed as an alternative for medical and industrial imaging fields. The distributed x-ray source corresponds to a two dimensional array of micro (~100μm) x-ray cells similar in format to a field emission display. In this paper the electron field emission characteristics of a single of the proposed micro-sized x-ray cells are simulated. The field electron emission from the CNTs-based cathode is simulated using the Particle-In-Cell code OOPIC Pro. The electron source is simulated as a triode structure, composed of an emitting cathode, extracting grid and anode. The possibility of using focusing lenses to …

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Towards On-Line Voltage Stability Assessment Using Synchrophasors, Himanshu Subandhu Hirlekar Jan 2011

Towards On-Line Voltage Stability Assessment Using Synchrophasors, Himanshu Subandhu Hirlekar

Masters Theses

"Voltage instability has become a growing concern in the operation of power systems in recent years. The reason is that power systems all over are being operated with reduced margins because of increased demand exacerbated by a general reluctance to invest in improvement of the electric grid infrastructure. Until recently it was difficult to predict voltage instability in the on-line environment. However, advances in technology has made possible the on-line monitoring and assessment of voltage stability. Synchrophasors is a relatively new technology in the field of power systems which allows system operators to monitor the system conditions at specific measurement …

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Uncertainty Quantification Integrated To Computational Fluid Dynamic Modeling Of Synthetic Jet Actuators, Srikanth Adya Jan 2011

Uncertainty Quantification Integrated To Computational Fluid Dynamic Modeling Of Synthetic Jet Actuators, Srikanth Adya

Masters Theses

"The Point Collocation Non-Intrusive Polynomial Chaos (NIPC) method was applied to a stochastic synthetic jet actuator problem to demonstrate the integration of computationally efficient uncertainty quantification to the high-fidelity CFD modeling of Synthetic Jet Actuators. The uncertainty quantification approach was first implemented in two stochastic model problem cases for the prediction of peak exit plane velocity using a Fluid Dynamic Based analytical model of the Synthetic Jet Actuator, which is computationally less expensive than CFD simulations. The NIPC results were compared with direct Monte Carlo sampling results. To demonstrate the efficient uncertainty quantification in CFD modeling of synthetic jet actuators, …

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Thermomechanics Of Curves In Space, Pavan Krishna Kanchi Jan 2011

Thermomechanics Of Curves In Space, Pavan Krishna Kanchi

Masters Theses

"Several biological molecules are known to form helices and coiled structures, such as DNA, collagen, bacterial flagella, and proteins. The backbones of such molecules may be modeled as a curve in three dimensions. A variational problem for the functional of the total free energy required to perturb moving curves in space is considered. The total energy of a curve in three dimensions is minimized y with a general intensive energy, which is a function of position, and the invariants, curvature and torsion. Three types of moduli are identified: stretching, bending and torsional moduli. As a result, three independent force balances …

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Optimal Control Of A Helicopter Unmanned Aerial Vehicle (Uav), David John Nodland Jan 2011

Optimal Control Of A Helicopter Unmanned Aerial Vehicle (Uav), David John Nodland

Masters Theses

"This thesis addresses optimal control of a helicopter unmanned aerial vehicle (UAV). Helicopter UAVs may be widely used for both military and civilian operations. Because these helicopters are underactuated nonlinear mechanical systems, high-performance controller design for them presents a challenge. This thesis presents an optimal controller design via both state and output feedback for trajectory tracking of a helicopter UAV using a neural network (NN). The state and output-feedback control system utilizes the backstepping methodology, employing kinematic and dynamic controllers while the output feedback approach uses an observer in addition to these controllers. The online approximator-based dynamic controller learns the …

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Phytoforensic Tools: Directional Uptake Of Chlorinated Solvents, Matthew Alan Limmer Jan 2011

Phytoforensic Tools: Directional Uptake Of Chlorinated Solvents, Matthew Alan Limmer

Masters Theses

"Trees have been used to locate contaminated soil and groundwater, augmenting traditional methods, such as well drilling, that are time-consuming and expensive. In the past decade, plant sampling has gained acceptance as a reliable method for site screening. In this new field of phytoforensics, research efforts focus on developing quicker, more accurate and more informative sampling and analysis methods for measuring contaminant concentrations in trees. These phytoforensic tools are a novel approach to site assessments, potentially reducing cost while more effectively locating contaminated groundwater. This thesis evolved from field data suggesting azimuthal concentrations in tree trunks may reflect the corresponding …

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A Numerical Study Of Novel Drag Reduction Techniques For Blunt Bodies In Hypersonic Flows, Christopher Marley Jan 2011

A Numerical Study Of Novel Drag Reduction Techniques For Blunt Bodies In Hypersonic Flows, Christopher Marley

Masters Theses

"Numerical simulations of a full three-dimensional hemispherical body in hypersonic flow are conducted and innovative techniques involving forward injection of gas from the stagnation point of the sphere are investigated; techniques include annular (ring) and swirled injection both with and without upstream energy deposition. Objectives of the analysis are the assessment of 1) drag reductions achieved on the blunt body (including the detrimental drag effect caused by the forward-facing injection itself) and 2) stability characteristics of the jet. Studies are conducted at free-stream Mach numbers of 10 and 6.5 at standard atmospheric conditions corresponding to 30 km altitude. While centered …

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Effects Of A Nickel Reactor Liner And Other Reaction Variables During Supercritical Water Reformation Of Glycerin, Michael S. Stever Jan 2011

Effects Of A Nickel Reactor Liner And Other Reaction Variables During Supercritical Water Reformation Of Glycerin, Michael S. Stever

Masters Theses

"The non-catalytic reformation of glycerin using supercritical water was conducted in a 400-mL tubular reactor constructed of Haynesʼ Alloy 230. The evaluated parameters for this thesis include water-to-glycerin molar ratios ranging from 3 to 24 and reactor temperatures ranging from 500⁰C to 700⁰C. In addition, experiments were performed using the Haynes' Alloy 230 reactor both without a liner and with a Nickel 201 liner. Space time was maintained at approximately 100 seconds and the reactor pressure was kept constant at 24.1 MPa. The resultant effect on product gas composition and carbon gasification was determined. The product gases consisted of a …

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Characterization Of Shielding Effectiveness For Metallic Enclosures, Nicholas Bennett Mentesana Jan 2011

Characterization Of Shielding Effectiveness For Metallic Enclosures, Nicholas Bennett Mentesana

Masters Theses

"This topic discusses and verifies an equation for estimating the shielding effectiveness of metallic enclosures through the use of numerical simulations. Using ideas from Bethe's "Theory of Diffraction by Small Holes", a previous student from the Missouri S&T Electromagnetic Compatibility Laboratory developed an equation that would yield an envelope prediction for the worst-case EMI from an aperture array backed by an over-moded cavity. Min Li (PhDEE '99) used results from measurements, simulations, and physics-based equations to formulate a simple equation that would predict these EMI levels. The main purpose of this thesis is to revisit this work and determine when …

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Mutual Attraction Guided Search: A Novel Solution Method To The Traveling Salesman Problem With Vehicle Dynamics, Jared Adam Nisbett Jan 2011

Mutual Attraction Guided Search: A Novel Solution Method To The Traveling Salesman Problem With Vehicle Dynamics, Jared Adam Nisbett

Masters Theses

"Traveling Salesman Problem (TSP) solution techniques are often used for route planning for automated vehicles. Most TSP solution methods focus on path length as the fitness reference, however in many cases, traversal time is of more practical importance. Mutual Attraction Guided Search (MAGS) is a novel solution method that uses an iterative process to simultaneously optimize both angle of travel through each target as well as the ordering of the targets in order to optimize path traversal time. MAGS deterministically locates a locally optimum solution quickly and can optimize for the acceleration limits of a specific vehicle rather than requiring …

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Computational Investigation Of Plasma Actuator As An Active Flow Control Strategy Of Laminar Separation Bubbles, Justin Roger Aholt Jan 2011

Computational Investigation Of Plasma Actuator As An Active Flow Control Strategy Of Laminar Separation Bubbles, Justin Roger Aholt

Masters Theses

"A parametric computational study designed to examine the plausibility of an external body force generated by active means, such as a plasma actuator, as a means of controlling a Laminar Separation Bubble (LSB) over an airfoil at low Reynolds numbers was conducted. Computational Fluid Dynamics (CFD) was employed to characterize the effect that a body force, localized to a small region tangent to the airfoil surface, might have on an LSB. In this study, the effects of altering the strength and location of the "actuator" on the size and location of the LSB and on the aerodynamic performance of the …

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Managing A Solar Sensor Array Project: Analyzing Insolation & Motivation, Beth A. Yount Jan 2011

Managing A Solar Sensor Array Project: Analyzing Insolation & Motivation, Beth A. Yount

Masters Theses

"The renewable power industry is rapidly growing today and is in need of much data to augment the advancement of the field. Photovoltaic technology, while making substantial improvement over the last 60 years, still has some significant hurdles to overcome. When shading, dust, or damaged cells reduce the power output of one panel, the traditional series-parallel configurations make it so every panel in series with that lower current panel, will also have its current lowered; this lowers the overall power output of the array significantly. Advancements in configurations and converters could change this phenomenon and dramatically increase a solar array's …

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Upgrade And Simulation Of The Subcritical Assembly At Missouri University Of Science And Technology, Lucas Powelson Tucker Jan 2011

Upgrade And Simulation Of The Subcritical Assembly At Missouri University Of Science And Technology, Lucas Powelson Tucker

Masters Theses

"The Missouri University of Science and Technology Subcritical Assembly (S&TSub) was brought back into service and upgraded with a new neutron detection system and internet access. Before the upgrade neutron counting was only possible in one location. Using a movable detection system housed in acrylic tubes measurements can now be taken in any empty fuel location and at any height within the tube, making three dimensional flux mapping a possibility. By connecting the new detection system to a Canberra Lynx Digital Signal Analyzer, remote users can have limited data collecting capabilities. To further enhance the potential of the facility, an …

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Numerical Comparison Of Thermal And Kinetic Modification Of Hydrogen And Oxygen, John Benjamin Gaither Jan 2011

Numerical Comparison Of Thermal And Kinetic Modification Of Hydrogen And Oxygen, John Benjamin Gaither

Masters Theses

"This document describes a new modeling technique used to compare thermal and kinetic modification of hydrogen and oxygen gas. The thermal model uses an equilibrium thermodynamic analysis to determine the heat required for given mole fractions of molecular and dissociated products. A kinetic model is developed for a mono-energetic electron beam and a Maxwellian energy distribution. The kinetic model uses electron impact cross sections for excitation, dissociation, and ionization tabulated from available source data between 0-1000 eV. Cross sections are used to calculate forward reaction rates, electron penetration depths, and associated product concentrations for excited, dissociated, and ionized species. The …

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3-Dimensional Computational Fluid Dynamics Modeling Of Solid Oxide Fuel Cell Using Different Fuels, Sachin Laxman Puthran Jan 2011

3-Dimensional Computational Fluid Dynamics Modeling Of Solid Oxide Fuel Cell Using Different Fuels, Sachin Laxman Puthran

Masters Theses

"Solid oxide fuel cell (SOFC) technology has been of great interest over many years due to its flexibility in using different fuels for operation; including the fundamental fuel i.e. Hydrogen. Various computational and numerical models have been developed along with experimental work to evaluate the performance as well as to identify and overcome the problems faced in the development of SOFC's. In an attempt to achieve efficient operation with respect to design and combined thermal and electrochemical perspective, the main objective of the proposed study is to present a three-dimensional computational model, which will serve as a framework for the …

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Analysis And Modeling Of Depth-Of-Cut During End Milling Of Deposited Material, Haythem Gaja Jan 2011

Analysis And Modeling Of Depth-Of-Cut During End Milling Of Deposited Material, Haythem Gaja

Masters Theses

"This study addresses depth-of-cut detection and tool-workpiece engagement using an acoustic emission monitoring system during milling machining for a deposited material. Online detection of depth-of-cut presents many technical difficulties. Researchers have used various types of sensors and methods to assess the depth-of-cut and surface errors. Due to the strong correlation between acoustic emission and cutting depth during the depth end milling process, it is useful to forecast the depth-of-cut from the acoustic emission signal. This work used regression analysis to model and detect the depth-of-cut. The experiments were carried out on a Fadal vertical 5-Axis computer numerical control machine using …

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Quantifying Model Uncertainty Using Measurement Uncertainty Standards, Harsheel Rajesh Shah Jan 2011

Quantifying Model Uncertainty Using Measurement Uncertainty Standards, Harsheel Rajesh Shah

Masters Theses

"Model uncertainty quantification is mainly concerned with the problem of determining whether the observed data is consistent with the model prediction. In real world, there is always a disagreement between a simulation model prediction and the reality that the model intends to represent. Our increased dependence on computer models emphasizes on model uncertainty which is present due to uncertainties in model parameters, lack of appropriate knowledge, assumptions and simplification of processes. In addition, when models predict multi-variate data, the experimental observation and model predictions are highly correlated. Thus, quantifying the uncertainty has a basic requirement of comparison between observation and …

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