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Faculty Publications

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Articles 631 - 660 of 3294

Full-Text Articles in Engineering

Managing Aquifer Recharge To Overcome Overdraft In The Lower American River, California, Usa, Mahesh L. Maskey, Mustafa S. Dogan, Angel Santiago Fernandez-Bou, Liying Li, Alexander Guzman, Wyatt Arnold, Erfan Goharian, Jay R. Lund, Josue Medellin-Azuara Mar 2022

Managing Aquifer Recharge To Overcome Overdraft In The Lower American River, California, Usa, Mahesh L. Maskey, Mustafa S. Dogan, Angel Santiago Fernandez-Bou, Liying Li, Alexander Guzman, Wyatt Arnold, Erfan Goharian, Jay R. Lund, Josue Medellin-Azuara

Faculty Publications

Frequent and prolonged droughts challenge groundwater sustainability in California but managing aquifer recharge can help to partially offset groundwater overdraft. Here, we use managed aquifer recharge (MAR) to examine potential benefits of adding an artificial recharge facility downstream from California’s Lower American River Basin, in part to prepare for drought. We use a statewide hydroeconomic model, CALVIN, which integrates hydrology, the economics of water scarcity cost and operations, environmental flow requirements, and other operational constraints, and allocates water monthly to minimize total scarcity and operating costs. This study considers a recharge facility with unconstrained and constrained flows. The results show …

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Intermediate Temperature Solid Oxide Cell With A Barrier Layer Free Oxygen Electrode And Phase Inversion Derived Hydrogen Electrode, Yongliang Zhang, Nansheng Xu, Qiming Tang, Kevin Huang Mar 2022

Intermediate Temperature Solid Oxide Cell With A Barrier Layer Free Oxygen Electrode And Phase Inversion Derived Hydrogen Electrode, Yongliang Zhang, Nansheng Xu, Qiming Tang, Kevin Huang

Faculty Publications

High-temperature solid oxide cells (SOCs) have fundamental advantages in efficiency and product rate over their low-temperature counterparts. However, the commercial development of SOCs is hindered by cost and reliability. To solve the issues, lowering the operating temperature of SOCs is deemed the best solution. Here we report on our effort toward intermediate temperature (IT) SOCs by developing a barrier layer free high-performance oxygen electrode and open structured hydrogen electrode. The results show that the new oxygen electrode provides reasonably good oxygen electrocatalytic activity at IT range for oxygen reduction and evolution reactions and the open structured hydrogen electrode provides low …

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A Statistical Principal Component Regression-Based Approach To Modeling The Degradative Effects Of Local Climate And Traffic On Airfield Pavement Performance, Evan M. Fortney, Steven J. Schuldt, Sarah L. Brown, James P. Allen, Justin D. Delorit Mar 2022

A Statistical Principal Component Regression-Based Approach To Modeling The Degradative Effects Of Local Climate And Traffic On Airfield Pavement Performance, Evan M. Fortney, Steven J. Schuldt, Sarah L. Brown, James P. Allen, Justin D. Delorit

Faculty Publications

Airfield pavement systems support the global economy, passenger travel, and national defense. Accurate pavement degradation predictions are critical inputs for maintenance and repair decisions, and when skillful, they may reduce the need for time-intensive, costly physical inspections that disrupt airfield operations. Existing airport pavement management systems (APMS) compute expected degradation as a function of pavement type and age, but they do not account for local climate and traffic conditions and they are not built to adapt to future changes in either mode of variability. This paper implements a bias-reduced statistical model that reveals the effects of local conditions using observed …

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Electron Mobility And Velocity In Ai 0.45 Ga 0.55 N-Channel Ultra-Wide Bandgap Hemts At High Temperatures For Rf Power Applications, Hansheng Ye, Mikhail Gaevski, Grigory Simin, Asif Khan, Patrick Fay Mar 2022

Electron Mobility And Velocity In Ai 0.45 Ga 0.55 N-Channel Ultra-Wide Bandgap Hemts At High Temperatures For Rf Power Applications, Hansheng Ye, Mikhail Gaevski, Grigory Simin, Asif Khan, Patrick Fay

Faculty Publications

Ultra-wide bandgap AlGaN has attracted recent attention as a promising channel material for next-generation high electron mobility transistors (HEMTs) for RF power due to its high critical field, excellent transport properties, and potential for operation in extreme environments. However, the effects of temperature on the transport properties are not fully understood. Here, Al0.62Ga0.38N/Al0.45Ga0.55N HEMTs have been fabricated and characterized up to 150 °C at DC and RF to evaluate the effect of temperature on electron mobility and carrier velocity. Measured results indicate that both mobility and carrier velocity exhibit modest dependence on …

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Behavior Of One-Way Reinforced Concrete Slabs With Polystyrene Embedded Arched Blocks, Ali Hussein Ali Al-Ahmed, Falah Hasan Ibrahim, Abbas Abdulmajeed Allawi, Ayman El-Zohairy Mar 2022

Behavior Of One-Way Reinforced Concrete Slabs With Polystyrene Embedded Arched Blocks, Ali Hussein Ali Al-Ahmed, Falah Hasan Ibrahim, Abbas Abdulmajeed Allawi, Ayman El-Zohairy

Faculty Publications

This study presents experimental and numerical investigations on seven one-way, reinforced concrete (RC) labs with a new technique of slab weight reduction using polystyrene-embedded arched blocks (PEABs). All slabs had the same dimensions, steel reinforcement, and concrete compressive strength. One of these slabs was a solid slab, which was taken as a control slab, while the other six slabs were cast with PEABs. The main variables were the ratio of the length of the PEABs to the length of the slab (lp/L) and the ratio of the height of the PEABs to the total slab depth (hP/H). The minimum decrease …

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Considerations For Radio Frequency Fingerprinting Across Multiple Frequency Channels, Jose A. Gutierrez Del Arroyo, Brett J. Borghetti, Michael A. Temple Mar 2022

Considerations For Radio Frequency Fingerprinting Across Multiple Frequency Channels, Jose A. Gutierrez Del Arroyo, Brett J. Borghetti, Michael A. Temple

Faculty Publications

Radio Frequency Fingerprinting (RFF) is often proposed as an authentication mechanism for wireless device security, but application of existing techniques in multi-channel scenarios is limited because prior models were created and evaluated using bursts from a single frequency channel without considering the effects of multi-channel operation. Our research evaluated the multi-channel performance of four single-channel models with increasing complexity, to include a simple discriminant analysis model and three neural networks. Performance characterization using the multi-class Matthews Correlation Coefficient (MCC) revealed that using frequency channels other than those used to train the models can lead to a deterioration in performance from …

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Madfam: Microarchitectural Data Framework And Methodology, Tor J. Langehaug, Scott R. Graham, Christine M. Schubert Kabban, Brett J. Borghetti Mar 2022

Madfam: Microarchitectural Data Framework And Methodology, Tor J. Langehaug, Scott R. Graham, Christine M. Schubert Kabban, Brett J. Borghetti

Faculty Publications

In the aftermath of Spectre and Meltdown researchers have proposed a variety of attack detection solutions by applying machine learning to data collected from hardware performance monitoring units. Although many microarchitectural attack detection systems provide high-accuracy detection results, the behavior of the underlying data collection mechanisms is not well described or understood. This research introduces the MicroArchitectural Data Framework And Methodology (MADFAM) to prescribe a systematic approach to collecting and preserving the information available in sequences of microarchitectural data. The proposed framework focuses on hardware performance counters (HPCs) as the primary data source. HPC configuration is complex, which makes it …

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Fourth-Order Adjoint Sensitivity And Uncertainty Analysis Of An Oecd/Nea Reactor Physics Benchmark: Ii. Computed Response Uncertainties, Ruixian Fang, Dan Gabriel Cacuci Mar 2022

Fourth-Order Adjoint Sensitivity And Uncertainty Analysis Of An Oecd/Nea Reactor Physics Benchmark: Ii. Computed Response Uncertainties, Ruixian Fang, Dan Gabriel Cacuci

Faculty Publications

This work quantifies the impact of the most important 4th-order sensitivities of the leakage response of a polyethylene-reflected plutonium (PERP) reactor physics benchmark with respect to the benchmark’s 180 group-averaged microscopic total cross sections, on the expected value, variance and skewness of the benchmark’s leakage response. This work shows that, as the standard deviations of the cross sections increase, the contributions of the 4th-order sensitivities to the response’s expected value and variance become significantly larger than the corresponding contributions stemming from the 1st-, 2nd- and 3rd-order sensitivities. Considering a uniform 5% relative standard deviation for all microscopic total cross sections, …

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Kinetic And Thermodynamic Analyses For Pyrolysis Of Hemp Hurds Using Discrete Distributed Activation Energy Model, Panuphong Mankeed, Thossaporn Onsree, Salman Raza Naqvi, Sirivatch Shimpalee, Nakorn Tippayawong Mar 2022

Kinetic And Thermodynamic Analyses For Pyrolysis Of Hemp Hurds Using Discrete Distributed Activation Energy Model, Panuphong Mankeed, Thossaporn Onsree, Salman Raza Naqvi, Sirivatch Shimpalee, Nakorn Tippayawong

Faculty Publications

In many counties, hemp is becoming a high-valued economic crop. Post-processing, more than 65% w/w of its starting material becomes waste. Herein, pyrolysis of hemp hurds/residues was investigated under low (10-50 degrees C/min) and intermediate (100-150 degrees C/min) heating rates using a discrete distributed activation energy model (DAEM). Thermochemical decomposition of hemp hurds occurred in three stages: drying, active pyrolysis, and char formation, accounting for 70-80% w/w overall weight loss. With the discrete DAEM, the model can be utilized for predicting pyrolysis behaviors of hemp hurds accurately with correlation coefficient of over 0.99. Different reaction mechanisms appeared between the low …

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Infrastructure Decision-Making Under Climate Change Uncertainty: Case Study Of Centralized Heating At Wright-Patterson Afb, Ohio, Tyler A. Ferry, Justin D. Delorit, Christopher M. Chini Mar 2022

Infrastructure Decision-Making Under Climate Change Uncertainty: Case Study Of Centralized Heating At Wright-Patterson Afb, Ohio, Tyler A. Ferry, Justin D. Delorit, Christopher M. Chini

Faculty Publications

Increased prevalence, lower cost, and reduced environmental impacts have granted natural gas status as a bridge fuel over the past decade in place of coal-fired heat and power generation across the United States. As a result, some coal facilities are retrofitting their systems to combust natural gas for heating and power. However, data and economic criteria surrounding these decisions are not widely available. Wright-Patterson Air Force Base (WPAFB) invested approximately $25 million, from 2014 to 2016, to retrofit two coal-fired steam-heat-generating plants with natural gas equipment. Economic analyses used to inform these long-term infrastructure decisions rarely consider the uncertainty of …

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Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz Mar 2022

Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz

Faculty Publications

Structural optimization is a methodology used to generate novel structures within a design space by finding a maximum or minimum point within a set of constraints. Topology optimization, as a subset of structural optimization, is often used as a means for light-weighting a structure while maintaining mechanical performance. This article presents the mathematical basis for topology optimization, focused primarily on the Bi-directional Evolutionary Structural Optimization (BESO) and Solid Isotropic Material with Penalization (SIMP) methodologies, then applying the SIMP methodology to a case study of additively manufactured lattice cells. Three lattice designs were used: the Diamond, I-WP, and Primitive cells. These …

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Thermo-Fluidic Transport Process In A Novel M-Shaped Cavity Packed With Non-Darcian Porous Medium And Hybrid Nanofluid: Application Of Artificial Neural Network (Ann), Dipak Kumar Mandal, Nirmalendu Biswas, Nirmal K. Manna, Dilip Kumar Gayen, Rama S. R. Gorla, Ali J. Chamkha Mar 2022

Thermo-Fluidic Transport Process In A Novel M-Shaped Cavity Packed With Non-Darcian Porous Medium And Hybrid Nanofluid: Application Of Artificial Neural Network (Ann), Dipak Kumar Mandal, Nirmalendu Biswas, Nirmal K. Manna, Dilip Kumar Gayen, Rama S. R. Gorla, Ali J. Chamkha

Faculty Publications

In this work, an attempt has been made to explore numerically the thermo-fluidic transport process in a novel M-shaped enclosure filled with permeable material along with Al2O3-Cu hybrid nanoparticles suspended in water under the influence of a horizontal magnetizing field. To exercise the influence of geometric parameters, a classical trapezoidal cavity is modified with an inverted triangle at the top to construct an M-shaped cavity. The cavity is heated isothermally from the bottom and cooled from the top, whereas the inclined sidewalls are insulated. The role of geometric parameters on the thermal performance is scrutinized thoroughly …

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Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi Feb 2022

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

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Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi Feb 2022

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

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Ph-Responsive Nanocarriers In Cancer Therapy, Nour M. Alsawaftah, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini Feb 2022

Ph-Responsive Nanocarriers In Cancer Therapy, Nour M. Alsawaftah, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini

Faculty Publications

A number of promising nano-sized particles (nanoparticles) have been developed to conquer the limitations of conventional chemotherapy. One of the most promising methods is stimuli-responsive nanoparticles because they enable the safe delivery of the drugs while controlling their release at the tumor sites. Different intrinsic and extrinsic stimuli can be used to trigger drug release such as temperature, redox, ultrasound, magnetic field, and pH. The intracellular pH of solid tumors is maintained below the extracellular pH. Thus, pH-sensitive nanoparticles are highly efficient in delivering drugs to tumors compared to conventional nanoparticles. This review provides a survey of the different strategies …

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Thermosensitive Polymers And Thermo-Responsive Liposomal Drug Delivery Systems, Waad H. Abuwatfa, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini Feb 2022

Thermosensitive Polymers And Thermo-Responsive Liposomal Drug Delivery Systems, Waad H. Abuwatfa, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini

Faculty Publications

Temperature excursions within a biological milieu can be effectively used to induce drug release from thermosensitive drug-encapsulating nanoparticles. Oncological hyperthermia is of particular interest, as it is proven to synergistically act to arrest tumor growth when combined with optimally-designed smart drug delivery systems (DDSs). Thermoresponsive DDSs aid in making the drugs more bioavailable, enhance the therapeutic index and pharmacokinetic trends, and provide the spatial placement and temporal delivery of the drug into localized anatomical sites. This paper reviews the fundamentals of thermosensitive polymers, with a particular focus on thermoresponsive liposomal-based drug delivery systems.

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Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci Feb 2022

Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work presents the fourth-order comprehensive sensitivity analysis methodology for nonlinear systems (abbreviated as “4th-CASAM-N”) for exactly and efficiently computing the first-, second-, third-, and fourth-order functional derivatives (customarily called “sensitivities”) of physical system responses (i.e., “system performance parameters”) to the system’s (or model) parameters. The qualifier “comprehensive” indicates that the 4th-CASAM-N methodology enables the exact and efficient computation not only of response sensitivities with respect to the customary model parameters (including computational input data, correlations, initial and/or boundary conditions) but also with respect to imprecisely known material boundaries, caused by manufacturing tolerances, of the system under consideration. The 4th-CASAM-N …

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Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu Feb 2022

Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu

Faculty Publications

Driven by the big data science, material informatics has attracted enormous research interests recently along with many recognized achievements. To acquire knowledge of materials by previous experience, both feature descriptors and databases are essential for training machine learning (ML) models with high accuracy. In this regard, the electronic charge density ρ(r), which in principle determines the properties of materials at their ground state, can be considered as one of the most appropriate descriptors. However, the systematic electronic charge density ρ(r) database of inorganic materials is still in its infancy due to the difficulties in …

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Strong Laser Polarization Control Of Coherent Phonon Excitation In Van Der Waals Material Fe3Gete2, Yu Gong, Ming Hu, Nico Harris, Zhonghua Yang, Ti Xie, Alem Teklu, Narayanan Kuthirummal, Jacob Koenemann, Xianghan Xu, Sang-Wook Cheong, Will Mcloud, Cheng Gong Feb 2022

Strong Laser Polarization Control Of Coherent Phonon Excitation In Van Der Waals Material Fe3Gete2, Yu Gong, Ming Hu, Nico Harris, Zhonghua Yang, Ti Xie, Alem Teklu, Narayanan Kuthirummal, Jacob Koenemann, Xianghan Xu, Sang-Wook Cheong, Will Mcloud, Cheng Gong

Faculty Publications

Optical manipulation of coherent phonon frequency in two-dimensional (2D) materials could advance the development of ultrafast phononics in atomic-thin platforms. However, conventional approaches for such control are limited to doping, strain, structural or thermal engineering. Here, we report the experimental observation of strong laser-polarization control of coherent phonon frequency through time-resolved pump-probe spectroscopic study of van der Waals (vdW) materials Fe3GeTe2. When the polarization of the pumping laser with tilted incidence is swept between in-plane and out-of-plane orientations, the frequencies of excited phonons can be monotonically tuned by as large as 3% (~100 GHz). Our first-principles …

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Hippocampal Ensembles Represent Sequential Relationships Among An Extended Sequence Of Nonspatial Events, Babak Shahbaba, Lingge Li, Forest Agostinelli, Mansi Saraf, Keiland W. Cooper, Derenik Haghverdian, Gabriel A. Elias, Pierre Baldi, Norbert J. Fortin Feb 2022

Hippocampal Ensembles Represent Sequential Relationships Among An Extended Sequence Of Nonspatial Events, Babak Shahbaba, Lingge Li, Forest Agostinelli, Mansi Saraf, Keiland W. Cooper, Derenik Haghverdian, Gabriel A. Elias, Pierre Baldi, Norbert J. Fortin

Faculty Publications

The hippocampus is critical to the temporal organization of our experiences. Although this fundamental capacity is conserved across modalities and species, its underlying neuronal mechanisms remain unclear. Here we recorded hippocampal activity as rats remembered an extended sequence of nonspatial events unfolding over several seconds, as in daily life episodes in humans. We then developed statistical machine learning methods to analyze the ensemble activity and discovered forms of sequential organization and coding important for order memory judgments. Specifically, we found that hippocampal ensembles provide significant temporal coding throughout nonspatial event sequences, differentiate distinct types of task-critical information sequentially within events, …

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Concurrent Identification And Characterization Of Protein Structure And Continuous Internal Dynamics With Redcraft, Hanin Omar, Aaron Hein, Casey A. Cole, Homayoun Valafar Feb 2022

Concurrent Identification And Characterization Of Protein Structure And Continuous Internal Dynamics With Redcraft, Hanin Omar, Aaron Hein, Casey A. Cole, Homayoun Valafar

Faculty Publications

Internal dynamics of proteins can play a critical role in the biological function of some proteins. Several well documented instances have been reported such as MBP, DHFR, hTS, DGCR8, and NSP1 of the SARS-CoV family of viruses. Despite the importance of internal dynamics of proteins, there currently are very few approaches that allow for meaningful separation of internal dynamics from structural aspects using experimental data. Here we present a computational approach named REDCRAFT that allows for concurrent characterization of protein structure and dynamics. Here, we have subjected DHFR (PDB-ID 1RX2), a 159-residue protein, to a fictitious, mixed mode model of …

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A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen Feb 2022

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

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A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen Feb 2022

A Survey Of Blind Modulation Classification Techniques For Ofdm Signals, Anand Kumar, Sudhan Majhi, Guan Gui, Hsiao-Chun Wu, Chau Yuen

Faculty Publications

Blind modulation classification (MC) is an integral part of designing an adaptive or intelligent transceiver for future wireless communications. Blind MC has several applications in the adaptive and automated systems of sixth generation (6G) communications to improve spectral efficiency and power efficiency, and reduce latency. It will become a integral part of intelligent software-defined radios (SDR) for future communication. In this paper, we provide various MC techniques for orthogonal frequency division multiplexing (OFDM) signals in a systematic way. We focus on the most widely used statistical and machine learning (ML) models and emphasize their advantages and limitations. The statistical-based blind …

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An Artificial Intelligence Approach To Fatigue Crack Length Estimation From Acoustic Emission Waves In Thin Metallic Plates, Joseph Chandler Garrett, Hanfei Mei, Victor Giurgiutiu Jan 2022

An Artificial Intelligence Approach To Fatigue Crack Length Estimation From Acoustic Emission Waves In Thin Metallic Plates, Joseph Chandler Garrett, Hanfei Mei, Victor Giurgiutiu

Faculty Publications

The acoustic emission (AE) technique has become a well-established method of monitoring structural health over recent years. The sensing and analysis of elastic AE waves, which have involved piezoelectric wafer active sensors (PWAS) and time domain and frequency domain analysis, has proven to be effective in yielding fatigue crack-related information. However, not much research has been performed regarding (i) the correlation between the fatigue crack length and AE signal signatures and (ii) artificial intelligence (AI) methodologies to automate the AE waveform analysis. In this paper, this crack length correlation is investigated along with the development of a novel AE signal …

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A Comparison Of Sporadic-E Occurrence Rates Using Gps Radio Occultation And Ionosonde Measurements, Rodney Carmona, Omar A. Nava, Eugene V. Dao, Daniel J. Emmons Jan 2022

A Comparison Of Sporadic-E Occurrence Rates Using Gps Radio Occultation And Ionosonde Measurements, Rodney Carmona, Omar A. Nava, Eugene V. Dao, Daniel J. Emmons

Faculty Publications

Sporadic-E (Es) occurrence rates from Global Position Satellite radio occultation (GPS-RO) measurements have shown to vary by a factor of five between studies, motivating the need for a comparison with ground-based measurements. In an attempt to find accurate GPS-RO techniques for detecting Es formation, occurrence rates derived using five previously developed GPS-RO techniques are compared to ionosonde measurements over an eight-year period from 2010–2017. GPS-RO measurements within 170 km of a ionosonde site are used to calculate Es occurrence rates and compared to the ground-truth ionosonde measurements. The techniques are compared individually for each ionosonde site …

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Robust Error Estimation Based On Factor-Graph Models For Non-Line-Of-Sight Localization, O. Arda Vanli, Clark N. Taylor Jan 2022

Robust Error Estimation Based On Factor-Graph Models For Non-Line-Of-Sight Localization, O. Arda Vanli, Clark N. Taylor

Faculty Publications

This paper presents a method to estimate the covariances of the inputs in a factor-graph formulation for localization under non-line-of-sight conditions. A general solution based on covariance estimation and M-estimators in linear regression problems, is presented that is shown to give unbiased estimators of multiple variances and are robust against outliers. An iteratively re-weighted least squares algorithm is proposed to jointly compute the proposed variance estimators and the state estimates for the nonlinear factor graph optimization. The efficacy of the method is illustrated in a simulation study using a robot localization problem under various process and measurement models and measurement …

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Generalized Cost-Effectiveness Of Residential Wind Mitigation Strategies For Wood-Frame, Single Family House In The Usa, Fatemeh Orooji, Carol J. Friedland, Rose Dominic Savio, Arash Taghinezhad, Carol C. Massarra, Nazla Bushra, Robert V. Rohli Jan 2022

Generalized Cost-Effectiveness Of Residential Wind Mitigation Strategies For Wood-Frame, Single Family House In The Usa, Fatemeh Orooji, Carol J. Friedland, Rose Dominic Savio, Arash Taghinezhad, Carol C. Massarra, Nazla Bushra, Robert V. Rohli

Faculty Publications

Wind is one of the deadliest and most expensive hazards in the United States. Wind hazards cause significant damage to buildings and economic losses to homeowners. Economic losses average approximately $3.8 billion annually from hurricane winds and are not decreasing, even despite enhanced construction practices to reduce wind damage. Thus, the effectiveness of mitigation strategies should be evaluated in order to lower the cost incurred by this hazard. Several studies have suggested building code improvements to mitigate the wind hazard, this additional comprehensive research provides selecting economically beneficial mitigation strategies to consider in building code revisions. In a step toward …

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Surface Acoustic Wave (Saw) Sensors: Physics, Materials, And Applications, Debdyuti Mandal, Sourav Banerjee Jan 2022

Surface Acoustic Wave (Saw) Sensors: Physics, Materials, And Applications, Debdyuti Mandal, Sourav Banerjee

Faculty Publications

Surface acoustic waves (SAWs) are the guided waves that propagate along the top surface of a material with wave vectors orthogonal to the normal direction to the surface. Based on these waves, SAW sensors are conceptualized by employing piezoelectric crystals where the guided elastodynamic waves are generated through an electromechanical coupling. Electromechanical coupling in both active and passive modes is achieved by integrating interdigitated electrode transducers (IDT) with the piezoelectric crystals. Innovative meta-designs of the periodic IDTs define the functionality and application of SAW sensors. This review article presents the physics of guided surface acoustic waves and the piezoelectric materials …

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Effect Of Defects Part I: Degradation Of Constitutive Coefficients As An Input To The Composite Failure Model With Microvoids And Porosity, Vahid Tavaf, Sourav Banerjee Jan 2022

Effect Of Defects Part I: Degradation Of Constitutive Coefficients As An Input To The Composite Failure Model With Microvoids And Porosity, Vahid Tavaf, Sourav Banerjee

Faculty Publications

It is always challenging to provide appropriate material properties for a composite progressive failure model. The nonstandard percentage reduction method that is commonly used to degrade the material constants with micro-scale defects generates tremendous uncertainty in failure prediction. The constitutive matrix is composed of multiple material constants. It is not necessary that all constants degrade either equally or linearly due to a certain state of material defects. With this very concern in mind, this article presents a guideline for using a quantified perturbation for each coefficient appropriately. It also presents distribution of effective material properties (EMPs) in unidirectional composite materials …

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Gibbs–Duhem Relation For Phase-Field Models Of Polymeric Mixtures, Rami Alhasan, Douglas R. Tree Jan 2022

Gibbs–Duhem Relation For Phase-Field Models Of Polymeric Mixtures, Rami Alhasan, Douglas R. Tree

Faculty Publications

Phase-field models are relatively inexpensive field-based models capable of capturing the nonequilibrium multiphase behavior of polymers and other soft materials. With their rise in popularity over the past several years, questions have arisen concerning the thermodynamic consistency of some model formulations. In doing so, researchers have employed several different forms of the Gibbs–Duhem equation─a classical thermodynamic relationship used to assess consistency─leading to questions about the correct form of this expression for inhomogeneous mixtures. In this paper, we derive a generalized Gibbs–Duhem relation that is valid for phase-field models. The key to the derivation is the recognition that the functional derivatives …

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