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Articles 1201 - 1230 of 3180

Full-Text Articles in Engineering

Naturally-Derived Extracellular Matrix Materials For Meniscus Repair And Regeneration, Jinglei Wu Aug 2017

Naturally-Derived Extracellular Matrix Materials For Meniscus Repair And Regeneration, Jinglei Wu

Bioengineering Dissertations - Archive

Human meniscus plays critical roles in a knee joint by transmitting weight-bearing force, absorbing shock, and stabilizing the knee joint capsule. Meniscal injuries are mainly caused by sports-related activities and age-related degeneration, which significantly reduce the life quality of patients. The injured meniscus has a very limited self-healing capability due to its poorly vascularized nature, specifically in the inner area. Surgical interventions are required to treat the injured meniscus, but the current treatments are not satisfactory because the post-surgery complications are frequently observed. Therefore, tissue regeneration approaches are developed to repair and functionally restore injured menisci. In this thesis, we …

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Techniques To Improve Ultrasound-Switchable Fluorescence Imaging, Jayanth Kandukuri Aug 2017

Techniques To Improve Ultrasound-Switchable Fluorescence Imaging, Jayanth Kandukuri

Bioengineering Dissertations - Archive

Novel approaches to the improvement of ultrasound-switchable fluorescence (USF) imaging—a relatively new imaging modality that combines ultrasound and optical imaging techniques—have been proposed for early cancer detection. In USF, a high-intensity focused ultrasound (HIFU) beam is used to induce temperature rise within its acoustic focal region due to which a thermo-sensitive USF contrast agent undergoes a switch in its state by increasing the output of fluorescence photons. By using an increase in fluorescence, one can isolate and quantify the fluorescence properties within the ultrasonic focal area. Therefore, USF is able to provide fluorescence contrast while maintaining ultrasound resolution in tissue. …

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Conditional Bias-Penalized Kalman Filter For Improved Estimation And Prediction Of Extremes, Miah Mohammad Saifuddin Aug 2017

Conditional Bias-Penalized Kalman Filter For Improved Estimation And Prediction Of Extremes, Miah Mohammad Saifuddin

Civil Engineering Theses - Archive

Kalman filter (KF) and its variants are widely used for real-time updating of model states and prediction in environmental sciences and engineering. Whereas in many applications the most important performance criteria may be the fraction of the times when the filter performs satisfactorily under different conditions, in many other applications the performance for estimation and prediction of extremes, such as floods, droughts, algal blooms, etc., may be of primary importance. Because KF is essentially a least squares solution, it is subject to conditional biases (CB) which arise from the error-in-variable, attenuation, effects when the model dynamics are highly uncertain, the …

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Hydrocarbon Pool Fire Performance Of Reinforced Elastomeric Bearing Pads, Shashank Malal Aug 2017

Hydrocarbon Pool Fire Performance Of Reinforced Elastomeric Bearing Pads, Shashank Malal

Civil Engineering Theses - Archive

Bearing pads are used as support for bridge girders to transfer the reaction forces to the substructure. They are designed to accommodate high axial loads from girder, shear deformations due to lateral thermal expansion of girder, and rotational deformation. Apart from these deformations bearing pads may also be subjected to thermal stresses due to daily temperature variations and extreme events like fire hazard. Current design methods do not account for these thermally induced stresses in elastomeric bearing pads. The objective of this research is to study the hydrocarbon pool fire performance of elastomeric bearing pad. This research has three parts. …

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Experimental And Computational Study Of Multi-Level Cooling Systems At Elevated Coolant Temperatures In Data Centers, Manasa Sahini Aug 2017

Experimental And Computational Study Of Multi-Level Cooling Systems At Elevated Coolant Temperatures In Data Centers, Manasa Sahini

Mechanical and Aerospace Engineering Dissertations - Archive

Data centers house a variety of compute, storage, network IT hardware where equipment reliability is of utmost importance. Heat generated by the IT equipment can substantially reduce its service life if T_(J,Max), maximum temperature that the microelectronic device tolerates to guarantee reliable operation, is exceeded. Hence, data center rooms are bound to maintain continuous conditioning of the cooling medium. This approach often results in over-provisioned cooling systems. In 2014, U.S. Data center electricity consumption is about 1.8% of the total electrical energy in the country. Hence, data center power and cooling have become significant issues facing the IT industry. The …

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Virtual Surveyor Based Object Extraction From Airborne Lidar Data, Md Ahsan Habib Aug 2017

Virtual Surveyor Based Object Extraction From Airborne Lidar Data, Md Ahsan Habib

Electrical Engineering Dissertations - Archive

Topographic feature detection of land cover from LiDAR data is important in various fields - city planning, disaster response and prevention, soil conservation, infrastructure or forestry. In recent years, feature classification, compliant with Object-Based Image Analysis (OBIA) methodology has been gaining traction in remote sensing and geographic information science (GIS). In OBIA, the LiDAR image is first divided into meaningful segments called object candidates. This results, in addition to spectral values, in a plethora of new information such as aggregated spectral pixel values, morphology, texture, context as well as topology. Traditional nonparametric segmentation methods rely on segmentations at different scales …

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Change Of Brain Network Connectivity Among Different Human Vigilance States Investigated By Eeg, Yudhajit Das Aug 2017

Change Of Brain Network Connectivity Among Different Human Vigilance States Investigated By Eeg, Yudhajit Das

Bioengineering Theses - Archive

Understanding the brain network connectivity associated with human vigilance states, to investigate the basic neural processes that underlie complex higher-order cognitive operations and functional domains, has become an important topic in biological science research. Also, there is growing concern about the prevalence and effects of sleep deprivation. Given the increasingly fast-paced nature of our society, the focus of the researchers is not only to identify the changes occurring within the brain during sleeping stages, but also to extract meaningful psycho-behavioral reason behind such change patterns which can lead to an improved understanding of brain activity during sleep which may further …

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Prediction Of Process-Induced Defects By Ply-Drops In The Design Optimization Of A Complex Composite Laminate, Sitanshu Pandya Aug 2017

Prediction Of Process-Induced Defects By Ply-Drops In The Design Optimization Of A Complex Composite Laminate, Sitanshu Pandya

Mechanical and Aerospace Engineering Theses - Archive

The objective of this work is to characterize manufacturing process-induced warping defects due to ply drops in composite laminates to guide composite laminate design. Composite laminate optimization seeks weight efficient models, but the process can also generate complex ply geometry, which compounds the challenges of the already rigorous composite laminate manufacturing process. Increased design complexity enhances the likelihood of manufacturing process-induced defects like warping; therefore, it is important to predict such defects in the design phase to make the product more efficient yet producible and thereby avoid such defects. This work study is manufacturing process induced warpage in complex composite …

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Investigation And Proposed Remedy Of Vibration Problem In Industrial Crane System Due To Human Operation, Dustin C. Lorance Aug 2017

Investigation And Proposed Remedy Of Vibration Problem In Industrial Crane System Due To Human Operation, Dustin C. Lorance

Civil Engineering Theses - Archive

A recent investigation of a crane system began when a facilities manager reported a runway beam under-going torsional vibration during operations. The investigation revealed the runway beam’s twisting was caused by resonance vibration due to “inching” of the crane hoist. A Fourier spectrum analysis revealed that one of the harmonic frequencies of this rhythmical motion coincided very close to the natural frequency of the crane system. The runway beam, although met strength requirements, failed to meet serviceability criteria due to the resonance vibration. Resonance vibration issues due to human activity in crane operation (inching, sway, etc.) is often encountered by …

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Performance Of Lime- And Cement- Based Treatments Of Sulfate-Rich Soil Via Rc Testing, Azadeh Asghariastaneh Aug 2017

Performance Of Lime- And Cement- Based Treatments Of Sulfate-Rich Soil Via Rc Testing, Azadeh Asghariastaneh

Civil Engineering Theses - Archive

Chemical treatment of expansive sulfate-rich soils, particularly lime- and cement-based methods, had been rather popular due to their relatively low cost and ready availability. However, over the last few decades, extensively documented pavement failures, mainly caused by excessive heaving and/or shrinkage of lime- and cement-treated subgrades with moderate-to-high sulfate content, have led to thorough investigations to assess the actual feasibility and effectiveness of calcium based stabilizers in sulfate-rich soils. Studies have concluded, with solid experimental evidence, that the calcium present in the chemical stabilizers react with the sulfate and alumina of the treated soil to form Ettringite, an expansive mineral …

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Multi-Objective Two-Stage Stochastic Programming For Adaptive Interdisciplinary Pain Management With Piece-Wise Linear Network Transition Models, Gazi Md Daud Iqbal Aug 2017

Multi-Objective Two-Stage Stochastic Programming For Adaptive Interdisciplinary Pain Management With Piece-Wise Linear Network Transition Models, Gazi Md Daud Iqbal

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Pain is the most common symptom when a patient visits a physician. People experience pain throughout their lifetime at different degrees. If short term pain is not treated properly, then it can become long term pain, which is also known as chronic pain. The Eugene McDermott Center for pain management at UT Southwestern Medical Center conducts a two-stage pain management program for chronic pain. This research uses a two-stage stochastic programming approach to optimize personal adaptive treatment strategies for pain management. The goal is to generate adaptive treatment strategies using statistics based optimization approaches that can be used by physicians …

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A Supervised Approach For Training Gaussian Mixture Model Classifiers, Vineet Dilip Gundecha Aug 2017

A Supervised Approach For Training Gaussian Mixture Model Classifiers, Vineet Dilip Gundecha

Electrical Engineering Theses - Archive

A new method for training Gaussian Mixture Model (GMM) classifiers is presented. First, an objective function is defined in terms of the number of clusters, K, per class, the mean vectors, the inverse covariance matrices for each class, and the prior probabilities for each class. For each increment in K, gradients of the objective function improve upon the prior probabilities, mean vectors, and inverse covariance matrices. Improvement in accuracy for different data-sets are shown and results are compared with the EM algorithm.

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Multi-Source Uav-Based Object Classification Using Cnn’S And Data Acquisition System For Robotic Skin, Raghavendra Sriram Margasahayam Subrahamanyam Aug 2017

Multi-Source Uav-Based Object Classification Using Cnn’S And Data Acquisition System For Robotic Skin, Raghavendra Sriram Margasahayam Subrahamanyam

Electrical Engineering Theses - Archive

Autonomous robots are intelligent systems capable of performing tasks in the world by themselves, without explicit human control. Examples range from autonomous helicopters to Roomba, the robot vacuum cleaner to robotic manipulators. The numerous sensors onboard gather data related to the desired actions and this poses several challenges and design constraints in terms of computation and hardware design that can prove to be extremely difficult and expensive to avoid. The objective of this research is to study, develop and implement various Intelligent solutions to help solve several real-world problems with respect to multi agent configurations of unmanned systems. We shall …

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Making Public Health Performance Measures For Transportation Accessible To Practitioners, Ziaur Rahman Aug 2017

Making Public Health Performance Measures For Transportation Accessible To Practitioners, Ziaur Rahman

Civil Engineering Dissertations - Archive

Pollutants emitted into the atmosphere from static and mobile sources pose a threat to human health. The detrimental impact associated with air pollution varies by the type of pollutant, the magnitude, frequency and duration of exposure, and the associated toxicity. While stationary sources play an important role in air pollution, motor vehicle exhaust emissions represent the single largest source of regional air pollution in urban areas. Moreover, outdoor physical activity requires an increased oxygen level with an increase in exercise intensity. Research has shown that both the ventilation and deposition fractions increase significantly during outdoor activities, which may lead to …

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Integrated Modeling Of Storm Drain And Natural Channel Networks For Real-Time Flash Flood Forecasting And Stormwater Planning And Management In Large Urban Areas, Hamideh Habibi Aug 2017

Integrated Modeling Of Storm Drain And Natural Channel Networks For Real-Time Flash Flood Forecasting And Stormwater Planning And Management In Large Urban Areas, Hamideh Habibi

Civil Engineering Dissertations - Archive

Urban flash flooding is a serious problem in large highly populated areas such as the Dallas–Fort Worth metroplex (DFW). Being able to monitor and predict flash flooding at a high spatiotemporal resolution is critical to mitigating its threats and for cost effective emergency management. In this reserach, a high-resolution flash flood forecast system which operates in real time is developed for DFW using a gridded distributed hydrologic model and high-resolution quantitative precipitation estimates from the DFW Demostration Network of the Collaborative Adaptive Sensing of the Atmosphere (CASA) Program high-resolution X band radars and the National Weather Service (NWS) NEXRAD radar. …

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Theory And Applications Of Absorbing Guided-Mode Resonant Devices In Sensing, Communications, And Display, Alexander Leighton Fannin Aug 2017

Theory And Applications Of Absorbing Guided-Mode Resonant Devices In Sensing, Communications, And Display, Alexander Leighton Fannin

Electrical Engineering Dissertations - Archive

Guided-mode resonant (GMR) technology is incorporated into lossy dielectric materials to assist in the absorption of incident light for various applications. Varying topologies and methodologies are explored. A series of devices taking advantage of narrow band, coherent interferometry is found to work as a serviceable coherent perfect absorber (CPA) whereby the total transmittance through the device is tunable based upon the relative phase of two or more beams. The differing beams are shown to be exciting the same mode in the device enabling the interferometric function. A similar, active topology for use in electronically interrogable interfacing is explored. Multiple hybrid …

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Adaptive Optimal Tracking Of Uncertain Discrete-Time Systems, Bahare Kiumarsi Khomartash Aug 2017

Adaptive Optimal Tracking Of Uncertain Discrete-Time Systems, Bahare Kiumarsi Khomartash

Electrical Engineering Dissertations - Archive

Optimal feedback control design has been responsible for much of the successful performance of engineered systems in aerospace, manufacturing, industrial processes, vehicles, ships, robotics, and elsewhere. Although most control design methods concern only about the stability of the controlled systems, the stability is a bare minimum requirement and it is desired to design a controller by optimizing some predefined performance criteria. However, the classical optimal control methods rely on offline solutions to complicated Hamilton-Jacobi-Bellman (HJB) equations which require complete knowledge about the system dynamics. Therefore, they are not able to cope with uncertainties and changes in dynamics. This research presents …

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On Feature Extraction From Large Scale Linear Lidar Data, Partha Pratim Acharjee Aug 2017

On Feature Extraction From Large Scale Linear Lidar Data, Partha Pratim Acharjee

Electrical Engineering Dissertations - Archive

Airborne light detection and ranging (LiDAR) can generate co-registered elevation and intensity map over large terrain. The co-registered 3D map and intensity information can be used efficiently for different feature extraction application. In this dissertation, we developed two algorithms for feature extraction, and usages of features for practical applications. One of the developed algorithms can map still and flowing waterbody features, and another one can extract building feature and estimate solar potential on rooftops and facades. Remote sensing capabilities, distinguishing characteristics of laser returns from water surface and specific data collection procedures provide LiDAR data an edge in this application …

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Communication-Cognizant Control Of Microgrids, Fnu Shankar Abhinav Aug 2017

Communication-Cognizant Control Of Microgrids, Fnu Shankar Abhinav

Electrical Engineering Dissertations - Archive

The increased integration of power electronic devices, advanced software-based controllers, and communication networks has transformed the microgrid from a simple physical system into a cyber-physical system. In this work, advanced distributed control algorithms and communication network are leveraged to provide a robust control structure for AC and DC microgrids. Introduction of distributed control and communication networks in microgrids presents its own unique challenges, which has not been considered in existing literature. A noise-resilient distributed controller is proposed for synchronization of frequency and voltage in AC microgrids. Synchronization in AC microgrids is cast as an optimization problem, and solved using Alternating …

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Investigation Of The Plasma Electrolytic Oxidation Mechanism Of Titanium, Golsa Mortazavi Aug 2017

Investigation Of The Plasma Electrolytic Oxidation Mechanism Of Titanium, Golsa Mortazavi

Material Science and Engineering Dissertations - Archive

Plasma electrolytic oxidation (PEO) is an environmentally friendly technology capable of forming coatings with excellent adhesion strength at high deposition rates. The PEO process is particularly attractive for forming desirable oxide-based coatings in transition metals (Al, Ti, Mg) to improve their surface sensitive properties. At present, the PEO mechanism is not fully understood since the process includes complex processes that are difficult to study. However, understanding the PEO mechanism is essential to produce coatings with desirable characteristics for a variety of new applications. One critical PEO process parameter is the applied total current to the workpiece. The total applied current …

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Life Cycle Assessment And Cost-Benefit Analysis Of Landfill Mining At The City Of Denton Landfill, Umme Zakira Aug 2017

Life Cycle Assessment And Cost-Benefit Analysis Of Landfill Mining At The City Of Denton Landfill, Umme Zakira

Civil Engineering Theses - Archive

The concept of landfill mining has evolved the way of transforming the existing landfills from a final waste disposal site to a temporary storage location for the potentially valuable resources. The convergence of the sustainable material management and environmental protection issues have emerged the demand for the feasibility study of the landfill mining both in environmental and economic aspects considering the scope of potential resource recovery. Few studies have been conducted either on the environmental impacts on waste management (especially incineration) and operational options or generalized cost-benefit estimation for landfill mining project. Therefore, the present study aims to evaluate both …

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Using Approximate Dynamic Programming To Control An Electric Vehicle Charging Station System, Ying Chen Aug 2017

Using Approximate Dynamic Programming To Control An Electric Vehicle Charging Station System, Ying Chen

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Dynamic programming (DP) as a mathematical programming approach to optimize a system evolving over time has been applied to solve the multi-stage optimization problems in a lot of areas such as manufacturing systems and environmental engineering. Due to the “curses of dimensionality”, traditional DP method is only able to solve a low dimensional problem or problems under very limiting restrictions, In order to employ DP to solve high-dimensional practical complex systems, approximate dynamic programming (ADP) is proposed. Several versions of ADP has been introduced in the literature and for this study, the author takes advantage of design and analysis of …

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Reconfigurable All-Optical De-Multiplexing Via Spatial-Selective Frequency-Up-Conversion In Kai(2) Multimode Waveguide, Young Bong Kwon May 2017

Reconfigurable All-Optical De-Multiplexing Via Spatial-Selective Frequency-Up-Conversion In Kai(2) Multimode Waveguide, Young Bong Kwon

Electrical Engineering Dissertations - Archive

We investigate spatial-mode-selective frequency up-converters in ?(2) multimode waveguides for classical and quantum communication. For the classical application, our method works as spatial-mode de-multiplexer for mode-division-multiplexing (MDM) communication system. For the quantum application, mode-selective quantum frequency conversion (QFC) enables multidimensional quantum encoding (qudits rather than qubits) which could eventually contribute to higher capacity of quantum communication links (higher QKD rates). First, we numerically investigate mode-selective up-conversion in a slab waveguide (2D free space) and periodically-polled KTP (PPKTP) waveguide. A 2D slab waveguide model is proposed based on non-collinear sum frequency generation (SFG). This model enables the calculation of conversion efficiencies …

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Sparse Array For Wireless Sensor Networks And Wireless Communications, Hao Liang May 2017

Sparse Array For Wireless Sensor Networks And Wireless Communications, Hao Liang

Electrical Engineering Dissertations - Archive

Underwater target detection and recognition has been widely used nowadays. In this dissertation, we show that the 3-D nested-array system can provide O(N^2) degree of freedom by using only N physical sensors when the second order statistics of the received data is used, which means we can use less sensors to get a better performance. We propose a maximum likelihood (ML) estimation algorithm for underwater target size detection. Theoretical analysis illustrates that our underwater sensor network can tremendously reduce the variance of target estimation. We show that our ML estimator is unbiased and the variance of parameter estimation matches the …

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Lung Nodule Detection And Segmentation Using A Patch-Based Multi-Atlas Method, Mustafa Alam May 2017

Lung Nodule Detection And Segmentation Using A Patch-Based Multi-Atlas Method, Mustafa Alam

Electrical Engineering Dissertations - Archive

CT image based lung nodule detection is the most widely used and accepted method for detecting lung cancer. Most CT image based methods rely on supervised learning, which has a high number of false positives and need a large amount of pre-segmented training samples. These problems can be solved if an optimally small number of training sample images can be created, where each sample has lung nodules of similar size and shape as the target image of the actual patient. Based on this hypothesis, two algorithms are proposed for 2D CT images and 3D CT images respectively. Both algorithms use …

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Multi-Object Detection And Tracking In Sensor Networks And Video Sequences, Guohua Ren May 2017

Multi-Object Detection And Tracking In Sensor Networks And Video Sequences, Guohua Ren

Electrical Engineering Dissertations - Archive

Firstly the problem of tracking multiple objects using observations acquired at spatially scattered sensors is considered here. Sensors are measuring a sort of signal attenuation from the present targets/sources. Multiple moving targets may die and be born at some point of the monitored period while the states of the sources, e.g. temperature of a fire source, CO/CO2 density of gas source, are also changing with time. In the case of targets tracking, radar signals sent out by sensors and later bounced back from the surface of the targets are measured at sensors, and the task is to find out the …

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Gain Scheduling Controller For Aircraft With Mass And Inertia Variation, Eunyoung Kim May 2017

Gain Scheduling Controller For Aircraft With Mass And Inertia Variation, Eunyoung Kim

Mechanical and Aerospace Engineering Dissertations - Archive

Robustness is one of the main control design requirements for aircraft control.Robustness is sought in the stability and performance of closed loop system against various factors such as disturbance, measurement error, modeling error or un-modeled dynamics. In aircraft control design, it is common to assume that the mass and inertia properties of aircraft are constant. Further, aircraft is assumed to have symmetry inits mass distribution relative to its mid-vertical plane. There are, however, cases where the aircraft mass changes rapidly, most notably in aerial refueling operation.The mass change also results in changes in the inertia matrix. An aircraft may also …

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On Space Program Planning: Quantifying The Effects Of Spacefaring Goals And Strategies On The Solution Space Of Feasible Programs, Mark Douglas Coley May 2017

On Space Program Planning: Quantifying The Effects Of Spacefaring Goals And Strategies On The Solution Space Of Feasible Programs, Mark Douglas Coley

Mechanical and Aerospace Engineering Dissertations - Archive

An organization's space program represents the coalescence of top-level goals and strategies with the specific, lower-level combinations of mission architectures, hardware, and technology. High costs and long lead times necessitate substantial planning and key decisions to be made years, possibly decades, in advance. Unfortunately, the methods and processes available for planning have historically been unable to provide decision-makers with objective, quantitative information from both the top and lower levels of the space program. Instead, decision-makers are forced to turn to top-level, qualitative assessments, disconnected from any of the fundamental, technical details, where inconsistent comparisons and secondary effects often become the …

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Studying Effects Of Adhesive Layer On Electrical Signals Of Piezoelectric Transducer Bonded With Structure, Md Mazharul Islam May 2017

Studying Effects Of Adhesive Layer On Electrical Signals Of Piezoelectric Transducer Bonded With Structure, Md Mazharul Islam

Mechanical and Aerospace Engineering Dissertations - Archive

Piezoelectric wafer active sensors (PWAS) are the most attractive transducers for guided-wave or ultrasound based structural health monitoring (SHM) because of their light weight and compact size. In order to excite guided waves in a structure, the PWASs are usually bonded on the surface of the structure by adhesive materials. The electrical signal applied to the surface bonded PWAS is converted to mechanical deformation of the PWAS which in turn is transferred to the structure through the adhesive layer. Thus, understanding the effects of the adhesive layer on the electrical response of the PWAS enables us to optimize the mechanical …

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Nonlinear Model Predictive Control For Cooperative Control And Estimation, Pengkai Ru May 2017

Nonlinear Model Predictive Control For Cooperative Control And Estimation, Pengkai Ru

Mechanical and Aerospace Engineering Dissertations - Archive

Recent advances in computational power have made it possible to do expensive online computations for control systems. It is becoming more realistic to perform computationally intensive optimization schemes online on systems that are not intrinsically stable and/or have very small time constants. Being one of the most important optimization based control approaches, model predictive control (MPC) has attracted a lot of interest from the research community due to its natural ability to incorporate constraints into its control formulation. Linear MPC has been well researched and its stability can be guaranteed in the majority of its application scenarios. However, one issue …

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