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Full-Text Articles in Engineering

Is Geology Accreditation Needed? It Is Already Here!, Laurie C. Anderson, John S. Gierke, Jeffrey B. Connelly Feb 2024

Is Geology Accreditation Needed? It Is Already Here!, Laurie C. Anderson, John S. Gierke, Jeffrey B. Connelly

Michigan Tech Publications

No abstract provided.


Pilot Study On Improving Crash Data Accuracy In Kentucky Through University Collaboration, Michael A. Fields, Eric Green, Robert Kluger, Xu Zhang, Kirolos Haleem Feb 2024

Pilot Study On Improving Crash Data Accuracy In Kentucky Through University Collaboration, Michael A. Fields, Eric Green, Robert Kluger, Xu Zhang, Kirolos Haleem

Kentucky Transportation Center Research Report

Without high-quality crash data and robust interpretive/analytical tools to analyze these data, transportation agencies will struggle to develop evidence-based strategies for improving road safety. Crash narratives are one element of crash reports that pose especially acute interpretive challenges. These narratives supplement coded data and give an account of incidents authored by responding law enforcement officers. Despite their value, conducting manual reviews of the 150,000+ crash reports and narratives issued in Kentucky each year is not feasible. To address this challenge, reviewers examined approximately 8,000 crash narratives from calendar year 2020 using a proprietary web-based quality control tool to identify discrepancies …


Advancing Universal Id Through Demonstration Of Enabling Technologies, Joseph Crabtree, Andrew Martin, Jeeyen Koo, Brian Beaven Feb 2024

Advancing Universal Id Through Demonstration Of Enabling Technologies, Joseph Crabtree, Andrew Martin, Jeeyen Koo, Brian Beaven

Kentucky Transportation Center Research Report

The purpose of this project was to install, demonstrate, and evaluate two candidate technologies that could be used to achieve “Universal ID” (i.e., having a unique, electronically readable identifier on every commercial motor vehicle in the United States). The two technologies selected for this demonstration represent (1) a potential low-cost near-term solution (simple RFID tags and roadside readers) and (2) a potential future solution that leverages technology that is anticipated to be installed on all future vehicles to support a variety of connected-vehicle (CV) applications. For this demonstration project, both types of roadside reader technology were installed at three existing …


Quaternary Ammonia Compounds In Disinfectant Products: Evaluating The Potential For Promoting Antibiotic Resistance And Disrupting Wastewater Treatment Plant Performance, Zihao Lu, Anna K. Mahony, William A. Arnold, Christopher Marshall, Patrick J. Mcnamara Feb 2024

Quaternary Ammonia Compounds In Disinfectant Products: Evaluating The Potential For Promoting Antibiotic Resistance And Disrupting Wastewater Treatment Plant Performance, Zihao Lu, Anna K. Mahony, William A. Arnold, Christopher Marshall, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Quaternary ammonium compounds (QACs) are a class of compounds that were widely used as disinfectants during the COVID-19 pandemic and continue to be used as disinfecting agents. After consumer usage, QAC concentrations are diluted in wastewater as they enter wastewater treatment plants. At sub-inhibitory concentrations, QACs may have unintended repercussions, including increased antibiotic resistance and inhibition of process performance in wastewater treatment plants. This review first summarizes how QACs inhibit bacteria and then highlights the mechanisms by which QACs can promote antibiotic resistance in general. Reported environmental concentrations of QACs are compared to concentrations that are suspected to impact antibiotic …


Inhibited Surface Diffusion In Nanoporous Multi-Principal Element Alloy Thin Films Prepared By Vacuum Thermal Dealloying, Tibra Das Gupta, Thomas John Balk Feb 2024

Inhibited Surface Diffusion In Nanoporous Multi-Principal Element Alloy Thin Films Prepared By Vacuum Thermal Dealloying, Tibra Das Gupta, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

Nanoporous structures with 3D interconnected networks are traditionally made by dealloy- ing a binary precursor. Certain approaches for fabricating these materials have been applied to refrac- tory multi-principal element alloys (RMPEAs), which can be suitable candidates for high-temperature applications. In this study, nanoporous refractory multi-principal element alloys (np-RMPEAs) were fabricated from magnesium-based thin films (VMoNbTaMg) that had been prepared by magnetron sputtering. Vacuum thermal dealloying (VTD), which involves sublimation of a higher vapor pres- sure element, is a novel technique for synthesizing nanoporous refractory elements that are prone to oxidation. When VMoNbTaMg was heated under vacuum, a nanoporous structure was …


The Roles Of Carbonaceous Wastes For Catalysis, Energy, And Environmental Remediation, Chi Huey Ng, Mohd Aizzan Mistoh, Siow Hwa Teo, Andrea Galassi, Hin Taufiq-Yap, Nancy Julius Siambun, Jurry Foo, Coswald Stephen Sipaut, Jeffrey Seay, Jidon Janaun Feb 2024

The Roles Of Carbonaceous Wastes For Catalysis, Energy, And Environmental Remediation, Chi Huey Ng, Mohd Aizzan Mistoh, Siow Hwa Teo, Andrea Galassi, Hin Taufiq-Yap, Nancy Julius Siambun, Jurry Foo, Coswald Stephen Sipaut, Jeffrey Seay, Jidon Janaun

Chemical and Materials Engineering Faculty Publications

This article reviews recent studies about various generations of the carbon materials for their applications in energy and environmental remediation. The synthesis routes of the carbon materials including the condition parameters, interaction of precursors, dopants and carbon materials, as well as their physical/chemical properties are explicated first. Then, the application and mechanism of metal-free/metal-doped/non-metal-doped carbon materials are discussed in detail. Lastly, this review is ended with a summary and invigorating perspectives on the challenges and future directions at the forefront of the catalysis platform to take a step further for real application.


Characterizing Linearizable Qaps By The Level-1 Reformulation-Linearization Technique, Lucas Waddell, Warren Adams Feb 2024

Characterizing Linearizable Qaps By The Level-1 Reformulation-Linearization Technique, Lucas Waddell, Warren Adams

Faculty Journal Articles

The quadratic assignment problem (QAP) is an extremely challenging NP-hard combinatorial optimization program. Due to its difficulty, a research emphasis has been to identify special cases that are polynomially solvable. Included within this emphasis are instances which are linearizable; that is, which can be rewritten as a linear assignment problem having the property that the objective function value is preserved at all feasible solutions. Various known sufficient conditions for identifying linearizable instances have been explained in terms of the continuous relaxation of a weakened version of the level-1 reformulation-linearization-technique (RLT) form that does not enforce nonnegativity on a subset …


Life Cycle Assessment Of Hydrothermal Carbonization: A Review Of Product Valorization Pathways, Andrea Ogunleye, Joseph Flora, Nicole Berge Feb 2024

Life Cycle Assessment Of Hydrothermal Carbonization: A Review Of Product Valorization Pathways, Andrea Ogunleye, Joseph Flora, Nicole Berge

Faculty Publications

Hydrothermal carbonization (HTC) has the potential to be a sustainable and environmentally beneficial approach for organic waste treatment. It is likely that HTC product use will dictate the viability of large-scale HTC facilities; therefore, understanding the viability and environmental implications associated with HTC product valorization pathways is critical. The overall goal of this review is to gain an understanding of how HTC product valorization is currently being modeled in life cycle assessment studies, and to use such information to assess current research and/or data needs associated with product valorization. To accomplish this, a review of existing HTC literature was conducted …


Us Public Opinion About The Safety Of Gene Editing In The Agriculture And Medical Fields And The Amount Of Evidence Needed To Improve Opinions, Brandon R. Mcfadden, Joy N. Rumble, Kathryn A. Stofer, Kevin M. Folta Feb 2024

Us Public Opinion About The Safety Of Gene Editing In The Agriculture And Medical Fields And The Amount Of Evidence Needed To Improve Opinions, Brandon R. Mcfadden, Joy N. Rumble, Kathryn A. Stofer, Kevin M. Folta

Agricultural Economics and Agribusiness Faculty Publications and Presentations

Introduction: Implementation of gene editing in agriculture and medicine hinges on public acceptance. The objectives of this study were to explore U.S. public opinion about gene editing in agricultural and medical fields and to provide more insight into the relationship between opinions about the safety of gene editing and the potential impact of evidence to improve opinions about safety.

Methods: Data were from two samples of U.S. respondents: 1,442 respondents in 2021 and 3,125 respondents in 2022. Survey respondents provided their opinions about the safety of gene editing in the agricultural and medical fields and answered questions about the number …


Two-Scale Data-Driven Design For Heat Manipulation, Daicong Da, Wei Chen Feb 2024

Two-Scale Data-Driven Design For Heat Manipulation, Daicong Da, Wei Chen

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Data-driven methods have gained increasing attention in computational mechanics and design. This study investigates a two-scale data-driven design for thermal metamaterials with various functionalities. To address the complexity of multiscale design, the design variables are chosen as the components of the homogenized thermal conductivity matrix originating from the lower scale unit cells. Multiple macroscopic functionalities including thermal cloak, thermal concentrator, thermal rotator/inverter, and their combinations, are achieved using the developed approach. Sensitivity analysis is performed to determine the effect of each design variable on the desired functionalities, which is then incorporated into topology optimization. Geometric extraction demonstrates an excellent matching …


Evolvement Of Excusable Delay Clauses In Government Contracts Since The Covid-19 Pandemic, Jung Hyun Lee, Yunping Liang, Seyed Mohammad Ehsan Tabatabaee, Bryce Riccitelli Feb 2024

Evolvement Of Excusable Delay Clauses In Government Contracts Since The Covid-19 Pandemic, Jung Hyun Lee, Yunping Liang, Seyed Mohammad Ehsan Tabatabaee, Bryce Riccitelli

Durham School of Architectural Engineering and Construction: Faculty Publications

Excusable delay clauses in government construction contracts, often considered boilerplate with minimal modifications, have increased in attention since the outbreak of COVID-19. Despite the studies enumerating triggering events of the clause in the background of the pandemic, it is necessary to capture insights into how the unprecedented event is systematically accommodated by contract languages. The overarching goal of this study is to identify changes in contract languages over the pre-and post-pandemic eras by state departments of transportation (DOTs), focusing on excusable delay clauses. This study conducts a content analysis and a comparative analysis of state DOT construction contract documents, including …


Investigating The Structure And Performance Of Electrodes Made By Dry And Wet Slurry Processes, Kubra Uzun, Bhamiti Sharma, Bradley R. Frieberg, Ming Wang, Jiazhi Hu, Anita Li, Xiaosong Huang, Yang-Tse Cheng Feb 2024

Investigating The Structure And Performance Of Electrodes Made By Dry And Wet Slurry Processes, Kubra Uzun, Bhamiti Sharma, Bradley R. Frieberg, Ming Wang, Jiazhi Hu, Anita Li, Xiaosong Huang, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Performance, cost, and safety are vital factors in producing and handling lithium-ion batteries. Using a dry process reduces the cost and environmental impact of producing large-scale lithium-ion battery electrodes significantly as solvents are eliminated. Thus, in this study, solvent-free dry electrostatic spray deposition (ESD) and conventional slurry processes were compared to uncover the influence of the manufacturing process on thick LiNi 0.8Mn0.1Co 0.1O 2 (NMC 811) positive electrodes. More pressure during calendering was found necessary for the dry-made (dry) electrodes to have the same porosity, leading to more cracks within the NMC particles and better adhesion. At slower discharge rates, …


Experimental Investigation Of A Heat Pump Tumble Dryer With A Zeotropic Refrigerant Mixture, Melanie Cop, Riley Barta, Christiane Thomas, Ulrich Hesse Feb 2024

Experimental Investigation Of A Heat Pump Tumble Dryer With A Zeotropic Refrigerant Mixture, Melanie Cop, Riley Barta, Christiane Thomas, Ulrich Hesse

School of Mechanical Engineering Faculty Publications

Due to their high global warming potential (GWP), fluorinated refrigerants are being replaced in many heat pump and refrigeration systems. Especially in small systems such as heat pump tumble dryers (HPTD), the replacement of the globally used working fluid in this application, R134a, appears to be manageable. One established alternative is the use of hydrocarbon refrigerants. Within this research project, new zeotropic refrigerant blends of hydrocarbons are theoretically evaluated as retrofit substitutes for R134a in heat pump tumble dryers. The aim is to use the temperature glide inherent to zeotropic mixtures during phase change to increase the heat transfer efficiency …


Low Shear In Short-Term Impacts Endothelial Cell Traction And Alignment In Long-Term, Mohanish Chandurkar, Nikhil Mittal, Shaina P. Royer-Weeden, Steven D. Lehmann, Yeonwoo Rho, Sangyoon J. Han Feb 2024

Low Shear In Short-Term Impacts Endothelial Cell Traction And Alignment In Long-Term, Mohanish Chandurkar, Nikhil Mittal, Shaina P. Royer-Weeden, Steven D. Lehmann, Yeonwoo Rho, Sangyoon J. Han

Michigan Tech Publications

Within the vascular system, endothelial cells (ECs) are exposed to fluid shear stress (FSS), a mechanical force exerted by blood flow that is critical for regulating cellular tension and maintaining vascular homeostasis. The way ECs react to FSS varies significantly; while high, laminar FSS supports vasodilation and suppresses inflammation, low or disturbed FSS can lead to endothelial dysfunction and increase the risk of cardiovascular diseases. Yet, the adaptation of ECs to dynamically varying FSS remains poorly understood. This study focuses on the dynamic responses of ECs to brief periods of low FSS, examining its impact on endothelial traction-a measure of …


Analysis Of Wind Turbine Wake Dynamics By A Gaussian-Core Vortex Lattice Technique, Apurva Baruah, Fernando L. Ponta Feb 2024

Analysis Of Wind Turbine Wake Dynamics By A Gaussian-Core Vortex Lattice Technique, Apurva Baruah, Fernando L. Ponta

Michigan Tech Publications

The development and deployment of the next generation of wind energy systems calls for simulation tools that model the entire wind farm while balancing accuracy and computational cost. A full-system wind farm simulation must consider the atmospheric inflow, the wakes and consequent response of the multiple turbines, and the implementation of the appropriate farm-collective control strategies that optimize the entire wind farm’s output. In this article, we present a novel vortex lattice model that enables the effective representation of the complex vortex wake dynamics of the turbines in a farm subject to transient inflow conditions. This work extends the capabilities …


Low Shear In Short-Term Impacts Endothelial Cell Traction And Alignment In Long-Term, Mohanish K. Chandurkar, Nikhil Mittal, Shaina P. Royer-Weeden, Steven D. Lehmann, Yeonwoo Rho, Sangyoon J. Han Feb 2024

Low Shear In Short-Term Impacts Endothelial Cell Traction And Alignment In Long-Term, Mohanish K. Chandurkar, Nikhil Mittal, Shaina P. Royer-Weeden, Steven D. Lehmann, Yeonwoo Rho, Sangyoon J. Han

Michigan Tech Publications

Within the vascular system, endothelial cells (ECs) are exposed to fluid shear stress (FSS), a mechanical force exerted by blood flow that is critical for regulating cellular tension and maintaining vascular homeostasis. The way ECs react to FSS varies significantly; while high, laminar FSS supports vasodilation and suppresses inflammation, low or disturbed FSS can lead to endothelial dysfunction and increase the risk of cardiovascular diseases. Yet, the adaptation of ECs to dynamically varying FSS remains poorly understood. This study focuses on the dynamic responses of ECs to brief periods of low FSS, examining its impact on endothelial traction—a measure of …


Computational Modelling Of A Triaxial Vibrating Sample Magnetometer, Leo Rodriguez, Arjun Sapkota, Jonathan Alvarado, Jitendra S. Tate, Wilhelmus J. Geerts Feb 2024

Computational Modelling Of A Triaxial Vibrating Sample Magnetometer, Leo Rodriguez, Arjun Sapkota, Jonathan Alvarado, Jitendra S. Tate, Wilhelmus J. Geerts

Mechanical Engineering Faculty Publications

Magnetic Field Assisted Additive Manufacturing (MFAAM) enables 3D printing of magnetic materials of various shapes which exhibit a complex anisotropy energy surface containing contributions generated from different origins such as sample, particle, and agglomerate shape anisotropy, flow and field induced anisotropy, and particle crystal anisotropy. These novel magnet shapes require the need to measure the x, y, and z components of the magnetic dipole moment simultaneously to fully understand the magnetic reversal mechanism and unravel the complex magnetic anisotropy energy surface of 3D printed magnetic composites. This work aims to develop a triaxial vibrating sample magnetometer (VSM) by adding a …


High Temperatures And Low Soil Moisture Synergistically Reduce Switchgrass Yields From Marginal Field Sites And Inhibit Fermentation, Sarvada Chipkar, Kevin Kahmark, Sven Bohm, Mir Zaman Hussain, Leela Joshi, Karleigh M. Krieg, Jacob Aguado, Jasmine Cassidy, Pablo Lozano, Kevin Garland, Andrea Senyk, Derek J. Debrauske, Elizabeth Whelan, Morgan Davies, Paul Urban, G. Philip Robertson, Trey K. Sato, Stephen K. Hamilton, Kurt D. Thelen, Rebecca Ong Feb 2024

High Temperatures And Low Soil Moisture Synergistically Reduce Switchgrass Yields From Marginal Field Sites And Inhibit Fermentation, Sarvada Chipkar, Kevin Kahmark, Sven Bohm, Mir Zaman Hussain, Leela Joshi, Karleigh M. Krieg, Jacob Aguado, Jasmine Cassidy, Pablo Lozano, Kevin Garland, Andrea Senyk, Derek J. Debrauske, Elizabeth Whelan, Morgan Davies, Paul Urban, G. Philip Robertson, Trey K. Sato, Stephen K. Hamilton, Kurt D. Thelen, Rebecca Ong

Michigan Tech Publications

‘Marginal lands’ are low productivity sites abandoned from agriculture for reasons such as low or high soil water content, challenging topography, or nutrient deficiency. To avoid competition with crop production, cellulosic bioenergy crops have been proposed for cultivation on marginal lands, however on these sites they may be more strongly affected by environmental stresses such as low soil water content. In this study we used rainout shelters to induce low soil moisture on marginal lands and determine the effect of soil water stress on switchgrass growth and the subsequent production of bioethanol. Five marginal land sites that span a latitudinal …


In Vitro Assessment Of Protamine Toxicity With Neural Cells, Its Therapeutic Potential To Counter Chondroitin Sulfate Mediated Neuron Inhibition, And Its Effects On Reactive Astrocytes, Derek W. Nelson, Jessica L. Funnell, Conrad H. Cheung, Geraldine B. Quinones, Christina S. Mendoza, Marvin Bentley, Ryan J. Gilbert Feb 2024

In Vitro Assessment Of Protamine Toxicity With Neural Cells, Its Therapeutic Potential To Counter Chondroitin Sulfate Mediated Neuron Inhibition, And Its Effects On Reactive Astrocytes, Derek W. Nelson, Jessica L. Funnell, Conrad H. Cheung, Geraldine B. Quinones, Christina S. Mendoza, Marvin Bentley, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Multiple therapies have been studied to ameliorate the neuroinhibitory cues present after traumatic injury to the central nervous system. Two previous in vitro studies have demonstrated the efficacy of the Food and Drug Administration-approved cardiovascular therapeutic, protamine (PRM), to overcome neuroinhibitory cues presented by chondroitin sulfates; however, the effect of a wide range of PRM concentrations on neuronal and glial cells has not been evaluated. In this study, we investigate the therapeutic efficacy of PRM with primary cortical neurons, hippocampal neurons, mixed glial cultures, and astrocytes. The threshold for PRM toxicity is shown to be at or above 10 µg …


Measurements Of The Effective Stress Coefficient For Elastic Moduli Of Sandstone In Quasi-Static Regime Using Semiconductor Strain Gauges, Vassily Mikhaltsevitch, Maxim Lebedev Feb 2024

Measurements Of The Effective Stress Coefficient For Elastic Moduli Of Sandstone In Quasi-Static Regime Using Semiconductor Strain Gauges, Vassily Mikhaltsevitch, Maxim Lebedev

Research outputs 2022 to 2026

Numerous experimental and theoretical studies undertaken to determine the effective stress coefficient for seismic velocities in rocks stem from the importance of this geomechanical parameter both for monitoring changes in rock saturation and pore pressure distribution in connection with reservoir production, and for overpressure prediction in reservoirs and formations from seismic data. The present work pursues a task to determine, in the framework of a low-frequency laboratory study, the dependence of the elastic moduli of n-decane-saturated sandstone on the relationship between pore and confining pressures. The study was conducted on a sandstone sample with high quartz and notable clay content …


Computational Discovery Of Microstructured Composites With Optimal Stiffness-Toughness Trade-Offs, Beichen Li, Bolei Deng, Wan Shou, Tae-Hyun Oh, Yuanming Hu, Yiyue Luo, Liang Shi, Wojciech Matusik Feb 2024

Computational Discovery Of Microstructured Composites With Optimal Stiffness-Toughness Trade-Offs, Beichen Li, Bolei Deng, Wan Shou, Tae-Hyun Oh, Yuanming Hu, Yiyue Luo, Liang Shi, Wojciech Matusik

Mechanical Engineering Faculty Publications and Presentations

The conflict between stiffness and toughness is a fundamental problem in engineering materials design. However, the systematic discovery of microstructured composites with optimal stiffness-toughness trade-offs has never been demonstrated, hindered by the discrepancies between simulation and reality and the lack of data-efficient exploration of the entire Pareto front. We introduce a generalizable pipeline that integrates physical experiments, numerical simulations, and artificial neural networks to address both challenges. Without any prescribed expert knowledge of material design, our approach implements a nested-loop proposal-validation workflow to bridge the simulation-to-reality gap and find microstructured composites that are stiff and tough with high sample efficiency. …


Automating Selective Area Electron Diffraction Phase Identification Using Machine Learning, Nathaniel Tomczak, Jennifer Carter Feb 2024

Automating Selective Area Electron Diffraction Phase Identification Using Machine Learning, Nathaniel Tomczak, Jennifer Carter

Faculty Scholarship

Selective area electron diffraction (SAED) patterns can provide valuable insight into the structure of a material. However, the manual identification of collected patterns can be a significant bottleneck in the overall phase classification workflow. In this work, we utilize the recent advances in computer vision and machine learning (ML) to automate the indexing of SAED patterns. The performance of six different ML algorithms is demonstrated using metallic plutonium-zirconium alloys. The most successful approach trained a neural network (NN) to make a classification of the phase and zone axis, and then utilized a second NN to synthesize multiple independent predictions of …


Investigating The Effects Of Alcohol Consumption On Manual And Automated Driving: A Systematic Review, Miaomiao Dong, Yuni Lee, Jackie Cha, Gaojian Huang Feb 2024

Investigating The Effects Of Alcohol Consumption On Manual And Automated Driving: A Systematic Review, Miaomiao Dong, Yuni Lee, Jackie Cha, Gaojian Huang

Mineta Transportation Institute

There are direct correlations between drunk driving and car-related injuries, disabilities, and death. Autonomous vehicles (AVs) may provide useful driver support systems to prevent or reduce road accidents. However, AVs are not yet fully automated and require human drivers to take over the vehicle at times. Therefore, understanding how alcohol affects driving performance in both manual and automated driving is important because manual drives may offer insights into the takeover process in AVs. A systematic review of 53 articles from eight databases was conducted. Findings were categorized based on the human information processing model, which can be extended to the …


Beneath I-280: Excavating A Neighborhood Lost To San José Freeways, Leila Ullmann, Gordon Douglas Feb 2024

Beneath I-280: Excavating A Neighborhood Lost To San José Freeways, Leila Ullmann, Gordon Douglas

Mineta Transportation Institute

Throughout the 1960s and 1970s, thousands of people in San José, California were displaced from their homes as the state used eminent domain to purchase land and uproot neighborhoods for the construction of Interstate freeways. This report presents a multifaceted research and public knowledge effort that uncovers some of the communities buried beneath these freeways, in the area where I-280 and CA-87 meet today near downtown San José. The project builds primarily from previously unprocessed California Department of Transportation (CalTrans) archival documents, which this project studies for the first time. The records are rich in detail about valuation and sale …


Dl-Drl: A Double-Level Deep Reinforcement Learning Approach For Large-Scale Task Scheduling Of Multi-Uav, Xiao Mao, Guohua Wu, Mingfeng Fan, Zhiguang Cao, Witold Pedrycz Feb 2024

Dl-Drl: A Double-Level Deep Reinforcement Learning Approach For Large-Scale Task Scheduling Of Multi-Uav, Xiao Mao, Guohua Wu, Mingfeng Fan, Zhiguang Cao, Witold Pedrycz

Research Collection School Of Computing and Information Systems

Exploiting unmanned aerial vehicles (UAVs) to execute tasks is gaining growing popularity recently. To address the underlying task scheduling problem, conventional exact and heuristic algorithms encounter challenges such as rapidly increasing computation time and heavy reliance on domain knowledge, particularly when dealing with large-scale problems. The deep reinforcement learning (DRL) based methods that learn useful patterns from massive data demonstrate notable advantages. However, their decision space will become prohibitively huge as the problem scales up, thus deteriorating the computation efficiency. To alleviate this issue, we propose a double-level deep reinforcement learning (DL-DRL) approach based on a divide and conquer framework …


Glop: Learning Global Partition And Local Construction For Solving Large-Scale Routing Problems In Real-Time, Haoran Ye, Jiarui Wang, Helan Liang, Zhiguang Cao, Yong Li, Fanzhang Li Feb 2024

Glop: Learning Global Partition And Local Construction For Solving Large-Scale Routing Problems In Real-Time, Haoran Ye, Jiarui Wang, Helan Liang, Zhiguang Cao, Yong Li, Fanzhang Li

Research Collection School Of Computing and Information Systems

The recent end-to-end neural solvers have shown promise for small-scale routing problems but suffered from limited real-time scaling-up performance. This paper proposes GLOP (Global and Local Optimization Policies), a unified hierarchical framework that efficiently scales toward large-scale routing problems. GLOP partitions large routing problems into Travelling Salesman Problems (TSPs) and TSPs into Shortest Hamiltonian Path Problems. For the first time, we hybridize non-autoregressive neural heuristics for coarse-grained problem partitions and autoregressive neural heuristics for fine-grained route constructions, leveraging the scalability of the former and the meticulousness of the latter. Experimental results show that GLOP achieves competitive and state-of-the-art real-time performance …


Semantic Segmentation Of Longitudinal Thermal Images For Identification Of Hot And Cool Spots In Urban Areas, Vasantha Ramani, Pandarasamy Arjunan, Kameshwar Poolla, Clayton Miller Feb 2024

Semantic Segmentation Of Longitudinal Thermal Images For Identification Of Hot And Cool Spots In Urban Areas, Vasantha Ramani, Pandarasamy Arjunan, Kameshwar Poolla, Clayton Miller

Research Collection College of Integrative Studies

This work presents the analysis of semantically segmented, longitudinally, and spatially rich thermal images collected at the neighborhood scale to identify hot and cool spots in urban areas. An infrared observatory was operated over a few months to collect thermal images of different types of buildings on the educational campus of the National University of Singapore. A subset of the thermal image dataset was used to train state-of-the-art deep learning models to segment various urban features such as buildings, vegetation, sky, and roads. It was observed that the U-Net segmentation model with ‘resnet34’ CNN backbone has the highest mIoU score …


Residual Optical Absorption From Native Defects In Cdsip2 Crystals, Timothy D. Gustafson, Nancy C. Giles, Elizabeth M. Scherrer, Kevin T. Zawilski, Peter G. Schunemann, Kent L. Averett, Jonathan E. Slagle, Larry E. Halliburton Feb 2024

Residual Optical Absorption From Native Defects In Cdsip2 Crystals, Timothy D. Gustafson, Nancy C. Giles, Elizabeth M. Scherrer, Kevin T. Zawilski, Peter G. Schunemann, Kent L. Averett, Jonathan E. Slagle, Larry E. Halliburton

Faculty Publications

CdSiP2 crystals are used in optical parametric oscillators to produce tunable output in the mid-infrared. As expected, the performance of the OPOs is adversely affected by residual optical absorption from native defects that are unintentionally present in the crystals. Electron paramagnetic resonance (EPR) identifies these native defects. Singly ionized silicon vacancies (V-Si) are responsible for broad optical absorption bands peaking near 800, 1033, and 1907 nm. A fourth absorption band, peaking near 630 nm, does not involve silicon vacancies. Exposure to 1064 nm light when the temperature of the CdSiP2 crystal is near 80K converts …


Fibrous Finite Element Modeling Of The Optic Nerve Head Region, Mohammad R. Islam, Fengting Ji, Manik Bansal, Yi Hua, Ian A. Sigal Feb 2024

Fibrous Finite Element Modeling Of The Optic Nerve Head Region, Mohammad R. Islam, Fengting Ji, Manik Bansal, Yi Hua, Ian A. Sigal

Mechanical Engineering Faculty Publications

The optic nerve head (ONH) region at the posterior pole of the eye is supported by a fibrous structure of collagen fiber bundles. Discerning how the fibrous structure determines the region biomechanics is crucial to understand normal physiology, and the roles of biomechanics on vision loss. The fiber bundles within the ONH structure exhibit complex three-dimensional (3D) organization and continuity across the various tissue components. Computational models of the ONH, however, usually represent collagen fibers in a homogenized fashion without accounting for their continuity across tissues, fibers interacting with each other and other fiber-specific effects in a fibrous structure. We …


Identification Of Early Opportunities For Simultaneous H2 Separation And Co2 Storage Using Depleted Coal Seams, Masoud Aslannezhad, Mohammad Sayyafzadeh, Stefan Iglauer, Alireza Keshavarz Feb 2024

Identification Of Early Opportunities For Simultaneous H2 Separation And Co2 Storage Using Depleted Coal Seams, Masoud Aslannezhad, Mohammad Sayyafzadeh, Stefan Iglauer, Alireza Keshavarz

Research outputs 2022 to 2026

Hydrogen (H2) production by steam methane reforming (SMR) is an economically viable technique on a commercial scale. However, this process produces large amounts of carbon dioxide (CO2), which eventually negates the benefits of employing H2 as an industrial input and clean energy carrier. This issue has led to increasing interest in capturing CO2 emissions from SMR to produce H2. This study proposes and investigates the use of coalbed methane (CBM) resources for separating the mixture of H2 and CO2 gases. The competitive adsorption mechanism in CBM not only can separate the H2 gas from the mixture but also results into …