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Articles 1 - 30 of 16573

Full-Text Articles in Engineering

Automotive Intrusion Detection Based On Constant Can Message Frequencies Across Vehicle Driving Modes, Clinton Young, Habeeb Olufowobi, Gedare Bloom, Joseph Zambreno Mar 2019

Automotive Intrusion Detection Based On Constant Can Message Frequencies Across Vehicle Driving Modes, Clinton Young, Habeeb Olufowobi, Gedare Bloom, Joseph Zambreno

Electrical and Computer Engineering Conference Papers, Posters and Presentations

The modern automobile relies on numerous electronic control units communicating over the de facto standard of the controller area network (CAN) bus. This communication network was not developed with cybersecurity in mind. Many methods based on constant time intervals between messages have been proposed to address this lack of security issue with the CAN bus. However, these existing methods may struggle to handle variable time intervals between messages during transitions of vehicle driving modes. This paper proposes a simple and cost-effective method to ensure the security of the CAN bus that is based on constant message frequencies across vehicle driving ...


Anomaly Detection Approach Using Adaptive Cumulative Sum Algorithm For Controller Area Network, Habeeb Olufowobi, Uchenna Ezeobi, Eric Muhati, Gaylon Robinson, Clinton Young, Joseph Zambreno, Gedare Bloom Mar 2019

Anomaly Detection Approach Using Adaptive Cumulative Sum Algorithm For Controller Area Network, Habeeb Olufowobi, Uchenna Ezeobi, Eric Muhati, Gaylon Robinson, Clinton Young, Joseph Zambreno, Gedare Bloom

Electrical and Computer Engineering Conference Papers, Posters and Presentations

The modern vehicle has transformed from a purely mechanical system to a system that embeds several electronic devices. These devices communicate through the in-vehicle network for enhanced safety and comfort but are vulnerable to cyber-physical risks and attacks. A well-known technique of detecting these attacks and unusual events is by using intrusion detection systems. Anomalies in the network occur at unknown points and produce abrupt changes in the statistical features of the message stream. In this paper, we propose an anomaly-based intrusion detection approach using the cumulative sum (CUSUM) change-point detection algorithm to detect data injection attacks on the controller ...


Motion-Based Design Approach For A Novel Variable Friction Cladding Connection Used In Wind Hazard Mitigation, Yongqiang Gong, Liang Cao, Simon Laflamme, James Ricles, Spencer Quiel, Douglas Taylor Feb 2019

Motion-Based Design Approach For A Novel Variable Friction Cladding Connection Used In Wind Hazard Mitigation, Yongqiang Gong, Liang Cao, Simon Laflamme, James Ricles, Spencer Quiel, Douglas Taylor

Civil, Construction and Environmental Engineering Publications

Cladding systems typically serve architectural purposes and protect occupants against the external environment. It is possible to leverage these systems to enhance structural resiliency. A common application is the use of blast resistant panels for enhanced protection against man-made hazards, whereas energy is dissipated through sacrificial elements. However, because these protection systems are passive, their mitigation capabilities are bandwidth limited, therefore targeting single types of hazards. The authors have recently proposed a novel variable friction cladding connection (VFCC), which enables the leveraging of cladding inertia for mitigating blast, wind, and seismic hazards. The variation in the friction force is generated ...


Analyzing Drug Release Kinetics From Water-Soluble Polymers, Sean M. Kelly, Arun K. Upadhyay, Akash Mitra, Balaji Narasimhan Feb 2019

Analyzing Drug Release Kinetics From Water-Soluble Polymers, Sean M. Kelly, Arun K. Upadhyay, Akash Mitra, Balaji Narasimhan

Chemical and Biological Engineering Publications

The ability to develop predictive mathematical models of therapeutic release from pharmaceutical formulations has enormous potential to enhance our understanding of such systems and improve the controlled release of the payload. The current work describes the development and testing of a one-dimensional model of drug transport from amorphous, swelling/dissolving polymers. Model parameters such as the diffusivities of water and drug, the initial loading of the drug, the polymer dissolution rate, drug-polymer interactions, and the tablet thickness were varied, demonstrating the ability to tune the release to be controlled by either drug diffusion or polymer chain disentanglement. In addition, predictions ...


Stomatal Conductance Measurement For Toxicity Assessment In Zero-Effluent Constructed Wetlands: Effects Of Landfill Leachate On Hydrophytes, Andrzej Białowiec, Jacek A. Koziel, Piotr Manczarski Feb 2019

Stomatal Conductance Measurement For Toxicity Assessment In Zero-Effluent Constructed Wetlands: Effects Of Landfill Leachate On Hydrophytes, Andrzej Białowiec, Jacek A. Koziel, Piotr Manczarski

Agricultural and Biosystems Engineering Publications

In this research, we explore for the first time the use of leaf stomatal conductance (gs) for phytotoxicity assessment. Plants respond to stress by regulating transpiration. Transpiration can be correlated with stomatal conductance when the water vapor pressure gradient for transpiration is constant. Thus, our working hypothesis was that the gs measurement could be a useful indicator of the effect of toxic compounds on plants. This lab-scale study aimed to test the measurement of gs as a phytotoxicity indicator. Our model plants were two common hydrophytes used in zero-effluent constructed wetlands for treating landfill leachate. The toxic influence of two ...


Pentablock Copolymer Micelle Nanoadjuvants Enhance Cytosolic Delivery Of Antigen And Improve Vaccine Efficacy While Inducing Low Inflammation, Sujata Senapati, Ross J. Darling, Darren Loh, Ian C. Schneider, Michael J. Wannemeuhler, Balaji Narasimhan, Surya K. Mallapragada Feb 2019

Pentablock Copolymer Micelle Nanoadjuvants Enhance Cytosolic Delivery Of Antigen And Improve Vaccine Efficacy While Inducing Low Inflammation, Sujata Senapati, Ross J. Darling, Darren Loh, Ian C. Schneider, Michael J. Wannemeuhler, Balaji Narasimhan, Surya K. Mallapragada

Chemistry Publications

As the focus has shifted from traditional killed or live, attenuated vaccines towards subunit vaccines, improvements in vaccine safety have been confronted with low immunogenicity of protein antigens. This issue has been addressed by synthesizing and designing a wide variety of antigen carriers and adjuvants, such as Toll-like receptor agonists (e.g., MPLA, CpG). Studies have focused on optimizing adjuvants for improved cellular trafficking, cytosolic availability, and improved antigen presentation. In this work, we describe the design of novel amphiphilic pentablock copolymer (PBC) adjuvants that exhibit high biocompatibility and reversible pH- and temperature-sensitive micelle formation. We demonstrate improved humoral immunity ...


Slip Of Shuffle Screw Dislocations Through Tilt Grain Boundaries In Silicon, Hao Chen, Valery Levitas, Liming Xiong Feb 2019

Slip Of Shuffle Screw Dislocations Through Tilt Grain Boundaries In Silicon, Hao Chen, Valery Levitas, Liming Xiong

Aerospace Engineering Publications

In this paper, molecular dynamics (MD) simulations of the interaction between tilt grain boundaries (GBs) and a shuffle screw dislocation in silicon are performed. Results show that dislocations transmit into the neighboring grain for all GBs in silicon. For Σ3, Σ9 and Σ19 GBs, when a dislocation interacts with a heptagon site, it transmits the GB directly. In contrast, when interacting with a pentagon site, it first cross slips to a plane on the heptagon site and then transmits the GB. The energy barrier is also quantified using the climbing image nudged elastic band (CINEB) method. Results show that Σ3 ...


Development Of Gelatin And Graphene-Based Nerve Regeneration Conduits Using 3d Printing Strategies For Electrical Transdifferentiation Of Mesenchymal Stem Cells, Metin Uz, Maxsam Donta, Meryem Mededovic, Donald S. Sakaguchi, Surya Mallapragada Feb 2019

Development Of Gelatin And Graphene-Based Nerve Regeneration Conduits Using 3d Printing Strategies For Electrical Transdifferentiation Of Mesenchymal Stem Cells, Metin Uz, Maxsam Donta, Meryem Mededovic, Donald S. Sakaguchi, Surya Mallapragada

Chemical and Biological Engineering Publications

In this study, gelatin and graphene-based nerve regeneration conduits/scaffolds possessing tailored 3D microstructures and mechanical properties were fabricated using 3D printing. The effect of 3D conduit microstructure and mechanical properties along with the applied electrical stimuli on mesenchymal stem cell (MSCs) behavior and transdifferentiation into Schwann cell (SC)-like phenotypes were investigated. The results indicated that the gelatin conduits/scaffolds had favorable 3D microstructural and mechanical properties for MSC attachment and growth. Immunocytochemistry results demonstrated that the application of electrical stimuli through the conductive graphene within the gelatin-based 3D microstructure had a profound effect on the differentiation of MSCs ...


Critical Analysis Of Case Law: Are Partnering Charters Binding?, Milagros Pinto Nunez, Douglas D. Gransberg Feb 2019

Critical Analysis Of Case Law: Are Partnering Charters Binding?, Milagros Pinto Nunez, Douglas D. Gransberg

Civil, Construction and Environmental Engineering Publications

Construction project partnering in the United States has been used successfully for nearly 30 years in reducing disputes. Most partnered projects are characterized by the joint development of a nonbinding partnering charter between the owner and the contractor, which encapsulates the project’s goals and lays out the desired process for resolving issues at the lowest level. This paper explores the outcomes when partnered projects fail and the parties involved must turn to the courts to settle their disputes. The paper evaluates the case law for 16 partnered projects through content analysis and cross-case comparison. The paper explores the question ...


Data Evidencing Slow Anaerobic Digestion In Emergency Treatment And Disposal Of Infectious Animal Carcasses, Jacek A. Koziel, Heekwon Ahn, Thomas D. Glanville, Timothy S. Frana, J. (Hans) Van Leeuwen, Lam T. Nguyen Feb 2019

Data Evidencing Slow Anaerobic Digestion In Emergency Treatment And Disposal Of Infectious Animal Carcasses, Jacek A. Koziel, Heekwon Ahn, Thomas D. Glanville, Timothy S. Frana, J. (Hans) Van Leeuwen, Lam T. Nguyen

Agricultural and Biosystems Engineering Publications

Burial of infectious and potentially infectious livestock and poultry animals is the most common response to an emergency situation. The data set summarizes 22-week-long experiment that simulates the environment found within conventional burial trenches for emergency disposal of animal carcasses, worldwide, sometimes with a topical application of quicklime as it is required in the Republic of Korea. This data set shows the rarely presented evidence of the extremely slow decay of animal carcasses. Besides visual evidence of no visible breakdown of carcass material, i.e., carcass (or carcass quarters and coarse cuts) still resembled the initial material at the end ...


Modeling Solid-Phase Microextraction Of Volatile Organic Compounds By Porous Coatings Using Finite Element Analysis, Bulat Kenessov, Miras Derbissalin, Jacek A. Koziel, Dmitry S. Kosyakov Jan 2019

Modeling Solid-Phase Microextraction Of Volatile Organic Compounds By Porous Coatings Using Finite Element Analysis, Bulat Kenessov, Miras Derbissalin, Jacek A. Koziel, Dmitry S. Kosyakov

Agricultural and Biosystems Engineering Publications

Experimental optimization of analytical methods based on solid-phase microextraction (SPME) is a complex and labor-intensive process associated with uncertainties. Using theoretical basics of SPME and finite element analysis software for the optimization proved to be an efficient alternative. In this study, an improved finite element analysis-based model for SPME of volatile organic compounds (VOCs) by porous coatings was developed mainly focussing on the mass transport in coatings. Benzene and the Carboxen/polydimethylsiloxane (Car/PDMS) coating were used as the model VOC and a porous SPME coating, respectively. It has been established that in the coating, volumetric fractions of Carboxen, PDMS ...


Interferometric Detection Of Pinned Interactions In Bismuth-Substituted Iron Garnet, L. Bauer, Neelam G. Prabhu Gaunkar, Mani Mina, J. W. Pritchard Jan 2019

Interferometric Detection Of Pinned Interactions In Bismuth-Substituted Iron Garnet, L. Bauer, Neelam G. Prabhu Gaunkar, Mani Mina, J. W. Pritchard

Industrial Design Publications

The utilization of a bismuth-substituted iron garnet as a magnetooptic Faraday rotator (MOFR) has been reported for all-optical networking purposes as well as for other applications. Our measurements and observations demonstrate that the MOFR saturates once a significantly large magnetic field (>225 G) is applied. After the applied magnetic field enters the saturation region, the material's magnetic domains can become pinned at intermediate levels of magnetization. Pinning in this form has not been reported nor well studied for this application. In this paper, a method to detect and describe anomalous pinning in terms of Faraday rotation is presented. Measurements ...


Pre-Methylation Of Lignin To Improve Storage Stability Of Oil Produced By Solvent Liquefaction, Jae-Young Kim, Parinaz Hafezi-Sefat, Sarah D. Cady, Ryan G. Smith, Robert C. Brown Jan 2019

Pre-Methylation Of Lignin To Improve Storage Stability Of Oil Produced By Solvent Liquefaction, Jae-Young Kim, Parinaz Hafezi-Sefat, Sarah D. Cady, Ryan G. Smith, Robert C. Brown

Mechanical Engineering Publications

In this study, we methylated hydroxyl groups (phenolic hydroxyl: Phe-OH and aliphatic hydroxyl: Aliph-OH) in soda lignin (SL) prior to solvent liquefaction to improve storage stability of the resulting oil. We investigated two methylating reagents, dimethyl sulfate (DMS) and dimethyl carbonate (DMC), for selective Phe-OH and total hydroxyl group (Phe-OH and Aliph-OH) blocking. Samples of SL, DMS-SL, and DMC-SL were depolymerized into oils under supercritical ethanol (350 °C). Both methylated lignins produced higher amounts of oils and smaller amounts of char compared to untreated SL due to suppressed charring reactions. Oil produced from SL had relatively higher functional group contents ...


On The Role Of Composition And Processing Parameters On The Microstructure Evolution Of Ti-Xmo Alloys, Michael Y. Mendoza, Peyman Samimi, David A. Brice, Iman Ghamarian, Matt Rolchigo, Richard Lesar, Peter Collins Jan 2019

On The Role Of Composition And Processing Parameters On The Microstructure Evolution Of Ti-Xmo Alloys, Michael Y. Mendoza, Peyman Samimi, David A. Brice, Iman Ghamarian, Matt Rolchigo, Richard Lesar, Peter Collins

Materials Science and Engineering Publications

Laser Engineered Net Shaping (LENS™) was used to produce a compositionally graded Ti-xMo (0 ≤ x ≤ 12 wt %) specimen and nine Ti-15Mo (fixed composition) specimens at different energy densities to understand the composition–processing–microstructure relationships operating using additive manufacturing. The gradient was used to evaluate the effect of composition on the prior-beta grain size. The specimens deposited using different energy densities were used to assess the processing parameters influence the microstructure evolutions. The gradient specimen did not show beta grain size reduction with the Mo content. The analysis from the perspective of the two grain refinement mechanisms based on a ...


Use Of Flexible Sensor To Characterize Biomechanics Of Canine Skin, Austin R. J. Downey, Jin Yan, Eric M. Zellner, Karl H. Kraus, Iris V. Rivero, Simon Laflamme Jan 2019

Use Of Flexible Sensor To Characterize Biomechanics Of Canine Skin, Austin R. J. Downey, Jin Yan, Eric M. Zellner, Karl H. Kraus, Iris V. Rivero, Simon Laflamme

Civil, Construction and Environmental Engineering Publications

Background: Suture materials and techniques are frequently evaluated in ex vivo studies by comparing tensile strengths. However, the direct measurement techniques to obtain the tensile forces in canine skin are not available, and, therefore, the conditions suture lines undergo is unknown. A soft elastomeric capacitor is used to monitor deformation in the skin over time by sensing strain. This sensor was applied to a sample of canine skin to evaluate its capacity to sense strain in the sample while loaded in a dynamic material testing machine. The measured strain of the sensor was compared with the strain measured by the ...


Development Of Time-Weighted Average Sampling Of Odorous Volatile Organic Compounds In Air With Solid-Phase Microextraction Fiber Housed Inside A Gc Glass Liner: Proof Of Concept, Madina Tursumbayeva, Jacek A. Koziel, Devin L. Maurer, Bulat Kenessov, Somchai Rice Jan 2019

Development Of Time-Weighted Average Sampling Of Odorous Volatile Organic Compounds In Air With Solid-Phase Microextraction Fiber Housed Inside A Gc Glass Liner: Proof Of Concept, Madina Tursumbayeva, Jacek A. Koziel, Devin L. Maurer, Bulat Kenessov, Somchai Rice

Agricultural and Biosystems Engineering Publications

Finding farm-proven, robust sampling technologies for measurement of odorous volatile organic compounds (VOCs) and evaluating the mitigation of nuisance emissions continues to be a challenge. The objective of this research was to develop a new method for quantification of odorous VOCs in air using time-weighted average (TWA) sampling. The main goal was to transform a fragile lab-based technology (i.e., solid-phase microextraction, SPME) into a rugged sampler that can be deployed for longer periods in remote locations. The developed method addresses the need to improve conventional TWA SPME that suffers from the influence of the metallic SPME needle on the ...


Enhancing The Co-Utilization Of Biomass-Derived Mixed Sugars By Yeasts, Meirong Gao, Deon Ploessl, Zengyi Shao Jan 2019

Enhancing The Co-Utilization Of Biomass-Derived Mixed Sugars By Yeasts, Meirong Gao, Deon Ploessl, Zengyi Shao

Chemical and Biological Engineering Publications

Plant biomass is a promising carbon source for producing value-added chemicals, including transportation biofuels, polymer precursors, and various additives. Most engineered microbial hosts and a select group of wild-type species can metabolize mixed sugars including oligosaccharides, hexoses, and pentoses that are hydrolyzed from plant biomass. However, most of these microorganisms consume glucose preferentially to non-glucose sugars through mechanisms generally defined as carbon catabolite repression. The current lack of simultaneous mixed-sugar utilization limits achievable titers, yields, and productivities. Therefore, the development of microbial platforms capable of fermenting mixed sugars simultaneously from biomass hydrolysates is essential for economical industry-scale production, particularly for ...


Investigating The Role Of Coil Designs And Anatomical Variations In Cerebellar Tms, Xiaojing Zhong, Priyam Rastogi, Yifei Wang, Erik G. Lee, David C. Jiles Jan 2019

Investigating The Role Of Coil Designs And Anatomical Variations In Cerebellar Tms, Xiaojing Zhong, Priyam Rastogi, Yifei Wang, Erik G. Lee, David C. Jiles

Electrical and Computer Engineering Publications

Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique that is used for treating various neurological disorders such as major depressive disorder. TMS has been gaining popularity in the field of neurostimulation of the cerebellum, since the cerebellum is a complex structure connected with almost the entire central nervous system and TMS has promise for non-invasively probing cerebellar function. Recent studies have discovered that the cerebellum plays an important role not only in motor planning and behavior but also in the cognitive domain. However, few studies have explored how different coil designs and anatomical variations affect the effectiveness of cerebellar ...


Evaluation Of An Intelligent Team Tutoring System For A Collaborative Two-Person Problem: Surveillance, Alec Ostrander, Desmond Bonner, Jamiahus Walton, Anna Slavina, Kaitlyn M. Ouverson, Adam Kohl, Stephen Gilbert, Michael Dorneich, Anne Sinatra, Eliot H. Winer Jan 2019

Evaluation Of An Intelligent Team Tutoring System For A Collaborative Two-Person Problem: Surveillance, Alec Ostrander, Desmond Bonner, Jamiahus Walton, Anna Slavina, Kaitlyn M. Ouverson, Adam Kohl, Stephen Gilbert, Michael Dorneich, Anne Sinatra, Eliot H. Winer

Industrial and Manufacturing Systems Engineering Publications

This paper describes the development and evaluation of an Intelligent Team Tutoring System (ITTS) for pairs of learners working collaboratively to monitor an area. In the Surveillance Team Tutor (STT), learners performed a surveillance task in a virtual environment, communicating to track hostile moving soldiers. This collaborative problem solving task required significant communication to achieve the common goal of perfect surveillance. In a pilot evaluation, 16 two-person teams performed the task within one of three feedback conditions (Individual, Team, or None) across four trials each. The STT used a unique approach to filtering feedback so that teams in both individual ...


High Throughput, Automated Prediction Of Focusing Patterns For Inertial Microfluidics, Aditya Kommajosula, Jeong-Ah Kim, Wonhee Lee, Baskar Ganapathysubramanian Jan 2019

High Throughput, Automated Prediction Of Focusing Patterns For Inertial Microfluidics, Aditya Kommajosula, Jeong-Ah Kim, Wonhee Lee, Baskar Ganapathysubramanian

Mechanical Engineering Publications

Visual inspections for identifying focusing points in inertial microfluidic flows are prone to misinterpreting stable locations and focusing shifts in the case of non-trivial focusing patterns. We develop and deploy an approach for automating the calculation of focusing patterns for a general channel geometry, and thereby reduce the dependence on empirical/visual procedures to confirm the presence of stable locations. We utilize concepts from interpolation theory (to represent continuous force-fields using discrete points), and stability theory to identify "basins of attraction" and quantitatively identify stable equilibrium points. Our computational experiments reveal that predicting equilibrium points accurately requires upto ×10-20 times ...


Notes On The Gridlab-D Household Equivalent Thermal Parameter Model, Leigh Tesfatsion, Swathi Battula Jan 2019

Notes On The Gridlab-D Household Equivalent Thermal Parameter Model, Leigh Tesfatsion, Swathi Battula

Economics Working Papers

GridLab-D (GLD) is an agent-based platform, developed by researchers at Pacific Northwest National Laboratory, that permits users to accurately simulate the state dynamics of power distribution systems at time scales ranging from sub-seconds to years. The purpose of this study is to present, in careful comprehensive form, a complete analytical state-space control representation for a version of the GLD Household Equivalent Thermal Parameter Model as support documentation for model users. This model is a physically-based implementation of a household with multiple price-responsive and conventional appliances whose thermal dynamics are determined over successive days by resident appliance usage and external weather ...


Effects Of Harvest Time On The Aroma Of White Wines Made From Cold-Hardy Brianna And Frontenac Gris Grapes Using Headspace Solid-Phase Microextraction And Gas Chromatography-Mass Spectrometry-Olfactometry, Somchai Rice, Madina Tursumbayeva, Matthew Clark, David Greenlee, Murlidhar Dharmadhikari, Anne Fennell, Jacek A. Koziel Jan 2019

Effects Of Harvest Time On The Aroma Of White Wines Made From Cold-Hardy Brianna And Frontenac Gris Grapes Using Headspace Solid-Phase Microextraction And Gas Chromatography-Mass Spectrometry-Olfactometry, Somchai Rice, Madina Tursumbayeva, Matthew Clark, David Greenlee, Murlidhar Dharmadhikari, Anne Fennell, Jacek A. Koziel

Agricultural and Biosystems Engineering Publications

The Midwest wine industry has shown a marked increase in growers, hectares planted, wineries, and wine production. This growth coincides with the release of cold-hardy cultivars such as Brianna and Frontenac gris, in 2001 and 2003, respectively. These white grape varieties account for one-third of the total area grown in the state of Iowa. It is generally accepted that the wine aroma profile plays a crucial role in developing a local, sustainable brand. However, the identity of Brianna/Frontenac Gris-based wine aromas and their link to the grape berry chemistry at harvest is unknown. This study aims to preliminarily characterize ...


Metabolic Engineering For Biocatalyst Robustness To Organic Inhibitors, Liam Royce, Laura R. Jarboe Jan 2019

Metabolic Engineering For Biocatalyst Robustness To Organic Inhibitors, Liam Royce, Laura R. Jarboe

Chemical and Biological Engineering Publications

Microbial production of biorenewable fuels and chemicals is often limited by inhibition of the biocatalyst, either by increasing concentrations of the product compound or by contaminant compounds in the biomass‐derived sugars. This inhibition can interfere with economically viable production. Here we discuss typical mechanisms of inhibition and methods for improving biocatalyst robustness. Inhibition often takes the form of inhibition of enzyme activity, depletion of cofactor pools, and membrane damage; methods are discussed for mitigating each of these types of inhibition. Various evolutionary schemes have been developed and implemented on a variety of inhibitory compounds, including butanol, acetic acid, furfural ...


Effect Of (Poly)Electrolytes On The Interfacial Assembly Of Peg Functionalized Gold Nanoparticles, Srikanth Nayak, Max Fieg, Wenjie Wang, Wei Bu, Surya Mallapragada, David Vaknin Jan 2019

Effect Of (Poly)Electrolytes On The Interfacial Assembly Of Peg Functionalized Gold Nanoparticles, Srikanth Nayak, Max Fieg, Wenjie Wang, Wei Bu, Surya Mallapragada, David Vaknin

Chemical and Biological Engineering Publications

We report on the effect of interpolymer complexes (IPCs) of poly(acrylic acid) (PAA) with poly(ethylene glycol) functionalized Au nanoparticles (PEG-AuNPs) as they assemble at the vapor-liquid interface, using surface sensitive synchrotron X-ray scattering techniques. Depending on the suspension pH, PAA functions both as a weak polyelectrolyte and a hydrogen bond donor, and these two roles affect the interfacial assembly of PEG-AuNPs differently. Above its isoelectric point, we find that PAA leads to the formation of a PEG-AuNPs monolayer at the interface with hexagonal structure. In the presence of high concentration of HCl (i.e., below the isoelectric point ...


Thin-Film Sensor For Fatigue Crack Sensing And Monitoring In Steel Bridges Under Varying Crack Propagation Rates And Random Traffic Loads, Xiangxiong Kong, Jian Li, Caroline Bennett, William Collins, Simon Laflamme, Hongki Jo Jan 2019

Thin-Film Sensor For Fatigue Crack Sensing And Monitoring In Steel Bridges Under Varying Crack Propagation Rates And Random Traffic Loads, Xiangxiong Kong, Jian Li, Caroline Bennett, William Collins, Simon Laflamme, Hongki Jo

Civil, Construction and Environmental Engineering Publications

Fatigue cracks are critical structural concerns for steel highway bridges, and fatigue initiation and propagation activity continues undetected between physical bridge inspections. Monitoring fatigue crack activity between physical inspections can provide far greater reliability in structural performance and can be used to prevent excessive damage and repair costs. In this paper, a thin-film strain sensor, called a soft elastomeric capacitor (SEC) sensor, is evaluated for sensing and monitoring fatigue cracks in steel bridges. The SEC is a flexible and mechanically robust strain sensor, capable of monitoring strain over large structural surfaces. By deploying multiple SECs in the form of dense ...


A Markovian Influence Graph Formed From Utility Line Outage Data To Mitigate Cascading, Kai Zhou, Ian Dobson, Zhaoyu Wang, Alexander Roitershtein, Arka P. Ghosh Jan 2019

A Markovian Influence Graph Formed From Utility Line Outage Data To Mitigate Cascading, Kai Zhou, Ian Dobson, Zhaoyu Wang, Alexander Roitershtein, Arka P. Ghosh

Electrical and Computer Engineering Publications

We use observed transmission line outage data to make a Markov influence graph that describes the probabilities of transitions between generations of cascading line outages, where each generation of a cascade consists of a single line outage or multiple line outages. The new influence graph defines a Markov chain and generalizes previous influence graphs by including multiple line outages as Markov chain states. The generalized influence graph can reproduce the distribution of cascade size in the utility data. In particular, it can estimate the probabilities of small, medium and large cascades. The influence graph has the key advantage of allowing ...


Camr: Coded Aggregated Mapreduce, Konstantinos Konstantinidis, Aditya Ramamoorthy Jan 2019

Camr: Coded Aggregated Mapreduce, Konstantinos Konstantinidis, Aditya Ramamoorthy

Electrical and Computer Engineering Publications

Many big data algorithms executed on MapReduce-like systems have a shuffle phase that often dominates the overall job execution time. Recent work has demonstrated schemes where the communication load in the shuffle phase can be traded off for the computation load in the map phase. In this work, we focus on a class of distributed algorithms, broadly used in deep learning, where intermediate computations of the same task can be combined. Even though prior techniques reduce the communication load significantly, they require a number of jobs that grows exponentially in the system parameters. This limitation is crucial and may diminish ...


Data-Driven Nonlinear Stabilization Using Koopman Operator, Bowen Huang, Xu Ma, Umesh Vaidya Jan 2019

Data-Driven Nonlinear Stabilization Using Koopman Operator, Bowen Huang, Xu Ma, Umesh Vaidya

Electrical and Computer Engineering Publications

We propose the application of Koopman operator theory for the design of stabilizing feedback controller for a nonlinear control system. The proposed approach is data-driven and relies on the use of time-series data generated from the control dynamical system for the lifting of a nonlinear system in the Koopman eigenfunction coordinates. In particular, a finite-dimensional bilinear representation of a control-affine nonlinear dynamical system is constructed in the Koopman eigenfunction coordinates using time-series data. Sample complexity results are used to determine the data required to achieve the desired level of accuracy for the approximate bilinear representation of the nonlinear system in ...


Distributed Matrix-Vector Multiplication: A Convolutional Coding Approach, Anindya B. Das, Aditya Ramamoorthy Jan 2019

Distributed Matrix-Vector Multiplication: A Convolutional Coding Approach, Anindya B. Das, Aditya Ramamoorthy

Electrical and Computer Engineering Publications

Distributed computing systems are well-known to suffer from the problem of slow or failed nodes; these are referred to as stragglers. Straggler mitigation (for distributed matrix computations) has recently been investigated from the standpoint of erasure coding in several works. In this work we present a strategy for distributed matrix-vector multiplication based on convolutional coding. Our scheme can be decoded using a low-complexity peeling decoder. The recovery process enjoys excellent numerical stability as compared to Reed-Solomon coding based approaches (which exhibit significant problems owing their badly conditioned decoding matrices). Finally, our schemes are better matched to the practically important case ...


Universally Decodable Matrices For Distributed Matrix-Vector Multiplication, Aditya Ramamoorthy, Li Tang, Pascal O. Vontobel Jan 2019

Universally Decodable Matrices For Distributed Matrix-Vector Multiplication, Aditya Ramamoorthy, Li Tang, Pascal O. Vontobel

Electrical and Computer Engineering Publications

Coded computation is an emerging research area that leverages concepts from erasure coding to mitigate the effect of stragglers (slow nodes) in distributed computation clusters, especially for matrix computation problems. In this work, we present a class of distributed matrix-vector multiplication schemes that are based on codes in the Rosenbloom-Tsfasman metric and universally decodable matrices. Our schemes take into account the inherent computation order within a worker node. In particular, they allow us to effectively leverage partial computations performed by stragglers (a feature that many prior works lack). An additional main contribution of our work is a companion matrix-based embedding ...