Engineering Commons^™

What Time Is It? Deep Learning Approaches For Circadian Rhythms, Forest Agostinelli, Nicholas Ceglia, Babak Shahbaba, Paolo Sassone-Corsi, Pierre Baldi

Faculty Publications

Motivation: Circadian rhythms date back to the origins of life, are found in virtually every species and every cell, and play fundamental roles in functions ranging from metabolism to cognition. Modern high-throughput technologies allow the measurement of concentrations of transcripts, metabolites and other species along the circadian cycle creating novel computational challenges and opportunities, including the problems of inferring whether a given species oscillate in circadian fashion or not, and inferring the time at which a set of measurements was taken.

Results: We first curate several large synthetic and biological time series datasets containing labels for both periodic and aperiodic …

Multi-Sensor Robust Relative Estimation Framework For Gps-Denied Multirotor Aircraft, Tim Mclain, Daniel P. Koch, Kevin M. Brink

Faculty Publications

An estimation framework is presented that improves the robustness of GPS-denied state estimation to changing environmental conditions by fusing updates from multiple view-based odometry algorithms. This allows the vehicle to utilize a suite of complementary exteroceptive sensors or sensing modalities. By estimating the vehicle states relative to a local coordinate frame collocated with an odometry keyframe, observability of the relative state is maintained. A description of the general framework is given, as well as the specific equations for a multiplicative extended Kalman filter with a multirotor vehicle. Experimental results are presented that demonstrate the ability of the proposed algorithm to …

Assessment Of A Writing Workshop Model For First-Year Engineering Students, Patricia Backer

Faculty Publications

This paper will report on a multi-year project to improve the writing skills of engineering freshmen at XXX University. For the last ten years, the college has offered an optional class to students who are not proficient in writing. Students can enroll in a one-unit lab class as many semesters as they wish to get practice in writing. The goal is to provide students with weekly writing activities that include: instruction in basic grammar, proofreading, and editing. In addition to study and practice exercises, students in this writing workshop have writing assignments, which provide practice in using correct grammar, spelling, …

Uav Path-Planning Using Bézier Curves And A Receding Horizon Approach, Bryce Ingersoll, Kyle Ingersoll, Patrick Defranco, Andrew Ning

Faculty Publications

Unmanned aerial vehicles (UAVs) are used in an increasing number of applications. Such applications may include navigating through heavy traffic and highly congested airways, where numerous static and dynamic obstacles impinge upon a UAV's flight. It is imperative that a UAV successfully avoids these obstacles, while improving its planned flight path according to certain criteria. We have modeled UAV path planning as a single objective optimization problem that utilizes a receding horizon approach, where the path is constrained to avoid obstacle collision and to account for flight aerodynamic constraints. The proposed method is gradient based, allowing for quick and robust …

High Density 3d Printed Microfluidic Valves, Pumps, And Multiplexers, Hua Gong, Adam T. Woolley, Gregory P. Nordin

Faculty Publications

In this paper we demonstrate that 3D printing with a Digital Light Processor stereolithographic (DLP-SLA) 3D printer can be used to create high density microfluidic devices with active components such as valves and pumps. Leveraging our previous work on optical formulation of inexpensive resins (RSC Adv. 5, 106621, 2015), we demonstrate valves with only 10% of the volume of our original 3D printed valves (Biomicrofluidics 9, 016501, 2015), which were already the smallest that have been reported. Moreover, we show that inclusion of a thermal initiator in the resin formulation along with a post-print bake can dramatically improve the durability …

Relative Navigation In Gps Degraded Environments, Timothy Mclain, David Wheeler, Paul W. Nyholm, Daniel P. Koch, Gary J. Ellingson, Benjamin J. Lewis, Randall W. Beard

Faculty Publications

For unmanned aircraft systems to become fully integrated into society, safe and reliable methods for estimation and control are required even when global measurements such as GPS are degraded or unavailable. In these situations, estimating the vehicle's global state directly leads to inaccuracy and inconsistency. The relative navigation framework avoids these issues by estimating the vehicle's state with respect to a current local coordinate frame associated with a visual odometry algorithm. A globally consistent and localized pose-graph map is produced by compounding these local estimates and opportunistically incorporating additional constraints such as GPS measurements and loop closures. This architecture increases …

Unequal A Priori Probability Multiple Hypothesis Testing In Space Domain Awareness With The Space Surveillance Telescope, Tyler J. Hardy, Stephen C. Cain, Travis F. Blake

Faculty Publications

This paper investigates the ability to improve Space Domain Awareness (SDA) by increasing the number of detectable Resident Space Objects (RSOs) from space surveillance sensors. With matched filter based techniques, the expected impulse response, or Point Spread Function (PSF), is compared against the received data. In the situation where the images are spatially undersampled, the modeled PSF may not match the received data if the RSO does not fall in the center of the pixel. This aliasing can be accounted for with a Multiple Hypothesis Test (MHT). Previously, proposed MHTs have implemented a test with an equal a priori prior …

Highly Conductive In-Sno2/Rgo Nano-Heterostructures With Improved Lithium-Ion Battery Performance, Ying Liu, Alessandro Palmieri, Junkai He, Yongtao Meng, Nicole Beauregard, Steven L. Suib, William E. Mustain

Faculty Publications

The increasing demand of emerging technologies for high energy density electrochemical storage has led many researchers to look for alternative anode materials to graphite. The most promising conversion and alloying materials do not yet possess acceptable cycle life or rate capability. In this work, we use tin oxide, SnO2, as a representative anode material to explore the influence of graphene incorporation and In-doping to increase the electronic conductivity and concomitantly improve capacity retention and cycle life. It was found that the incorporation of In into SnO2 reduces the charge transfer resistance during cycling, prolonging life. It is also hypothesized that …

Order Reduction Of Dae Models, John Hedengren, Thomas F. Edgar

Faculty Publications

This report outlines a technique for the order reduction of differential algebraic equations (DAEs). The order reduction is accomplished in two steps. First, algebraic states are partitioned into successive implicit sets of variables and equations by reconstructing the sparsity pattern into lower triangular block form. Second, proper orthogonal decomposition (POD) is used to reduce the number of differential states. As a test case for the theory, a dynamic binary distillation column model is analyzed with the generalized approach. The index 1 DAE model of 52 differential and 178 algebraic states is reduced to an ODE model of 26 differential states.

Maximization Of The Annual Energy Production Of Wind Power Plants By Optimization Of Layout And Yaw-Based Wake Control, Pieter Gebraad, Jared Thomas, Andrew Ning, Paul Fleming, Katherine Dykes

Faculty Publications

This paper presents a wind plant modeling and optimization tool that enables the maximization of wind plant annual energy production (AEP) using yaw-based wake steering control and layout changes. In order to make predictions of wind plant AEP, necessary extensions of the original wind plant wake interaction model include the coupling with a detailed rotor model and a control policy for turbine blade pitch and rotor speed. This coupling allows the prediction of power production with wake effects throughout a range of wind speeds. Results of an optimization study on a wind plant based on the Princess Amalia Wind Park …

Investigation Of 186Re Via Radiative Thermal-Neutron Capture On 185Re, David A. Matters, Andrew G. Lerch, A. M. Hurst, L. Szentmiklosi, J. J. Carroll, B. Detwiler, Zs. Revay, John W. Mcclory, Stephen R. Mchale, R. B. Firestone, B. W. Sleaford, M. Krticka, T. Belgya

Faculty Publications

Partial ��-ray production cross sections and the total radiative thermal-neutron capture cross section for the ¹⁸⁵Re(n,��)¹⁸⁶Re reaction were measured using the Prompt Gamma Activation Analysis facility at the Budapest Research Reactor with an enriched ¹⁸⁵Re target. The ¹⁸⁶Re cross sections were standardized using well-known ³⁵Cl(n,��)³⁶Cl cross sections from irradiation of a stoichiometric ^natReCl₃ target. The resulting cross sections for transitions feeding the ¹⁸⁶Re ground state from low-lying levels below a cutoff energy of E_c=746keV were combined with a modeled probability of ground-state feeding from levels above E …

The Impact Of Learning Curve Model Selection And Criteria For Cost Estimation Accuracy In The Dod, Candace Honious, Brandon Johnson, John J. Elshaw, A. B. Badiru

Faculty Publications

The first part of this manuscript examines the impact of configuration changes to the learning curve when implemented during production. This research is a study on the impact to the learning curve slope when production is continuous but a configuration change occurs. Analysis discovered the learning curve slope after a configuration change is different from the stable learning curve slope pre-configuration change. The newly configured units were statistically different from previous units. This supports that the new configuration should be estimated with a new learning curve equation. The research also discovered the post-configuration slope is always steeper than the stable …

Ubisol-Q10 Prevents Glutamate-Induced Cell Death By Blocking Mitochondrial Fragmentation And Permeability Transition Pore Opening, Santosh Kumari, Suresh L. Mehta, Gaolin Z. Milledge, Xinyu Huang, P Andy Li

Faculty Publications

Mitochondrial dysfunction and oxidative stress are the major events that lead to the formation of mitochondrial permeability transition pore (mPTP) during glutamate-induced cytotoxicity and cell death. Coenzyme Q10 (CoQ10) has widely been used for the treatment of mitochondrial disorders and neurodegenerative diseases. Comparing to traditional lipid-soluble CoQ10, water soluble CoQ10 (Ubisol-Q10) has high intracellular and intra-mitochondrial distribution. The aims of the present study are to determine the neuroprotective effects of Ubisol-Q10 on glutamate-induced cell death and to explore its functional mechanisms. HT22 neuronal cells were exposed to glutamate. Cell viability was measured and mitochondrial fragmentation was assessed by mitochondrial imaging. …

Moving Horizon Estimation For An Industrial Gas Phase Polymerization Reactor, Jasmeer Ramhal, Kenneth V. Allsford, John Hedengren

Faculty Publications

A large-scale set of differential and algebraic equations (DAEs) is used to model and control an industrial gas phase polymerization reactor. Moving horizon estimation, preceding the nonlinear control optimization, provides an estimate of the current states and unmeasured disturbances. MHE is compared to Implicit Dynamic Feedback (IDF^TM)^*. With MHE, there is improved estimation of unmodeled disturbances in the UNIPOL^TM** polyethylene plant. The polymerization model is converted to algebraic equations by orthogonal collocation and solved with the MHE objective function in a simultaneous optimization. NOVA^TM, an active-set sparse NLP solver, is used to converge …

Protein Synthesis Directly From Pcr: Progress And Applications Of Cell-Free Protein Synthesis With Linear Dna, Song-Min Schinn, Andrew Broadbent, William T. Bradley, Bradley Charles Bundy

Faculty Publications

A rapid, versatile method of protein expression and screening can greatly facilitate the future development of therapeutic biologics, proteomic drug targets and biocatalysts. An attractive candidate is cell-free protein synthesis (CFPS), a cell-lysate-based in vitro expression system, which can utilize linear DNA as expression templates, bypassing time-consuming cloning steps of plasmid-based methods. Traditionally, such linear DNA expression templates (LET) have been vulnerable to degradation by nucleases present in the cell lysate, leading to lower yields. This challenge has been significantly addressed in the recent past, propelling LET-based CFPS as a useful tool for studying, screening and engineering proteins in a …

Identification Of The Zinc-Oxygen Divacancy In Zno Crystals, Maurio S. Holston, Eric M. Golden, Brant E. Kananen, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton

Faculty Publications

An electron paramagnetic resonance (EPR) spectrum in neutron-irradiated ZnO crystals is assigned to the zinc-oxygen divacancy. These divacancies are observed in the bulk of both hydrothermally grown and seeded-chemical-vapor-transport-grown crystals after irradiations with fast neutrons. Neutral nonparamagnetic complexes consisting of adjacent zinc and oxygen vacancies are formed during the irradiation. Subsequent illumination below ∼150 K with 442 nm laser light converts these (V²⁻_Zn − V²⁺_O)⁰ defects to their EPR-active state (V⁻_Zn − V²⁺_O)⁺ as electrons are transferred to donors. The resulting photoinduced S = 1/2 spectrum of the …

Data Quality Challenges In Distributed Live-Virtual-Constructive Test Environments, Jeremy R. Millar, Douglas D. Hodson, Gilbert L. Peterson, Darryl K. Ahner

Faculty Publications

Live-Virtual-Constructive (LVC) simulations are complex systems comprising a combination of live (real people operating real equipment), virtual (real people operating simulated equipment or vice versa), and constructive (wholly simulated) entities. Nodes in the system support the simulation of one or more entities and are often geographically distributed to leverage unique assets (e.g., physical test range space or high-fidelity full motion simulators). Abstract excerpt © ACM

Ray-Based Statistical Propagation Modeling For Indoor Corridor Scenarios At 15 Ghz, Qi Wang, Bo Ai, David W. Matolak, Ruisi He, Xin Zhou

Faculty Publications

According to the demands for fifth-generation (5G) communication systems, high frequency bands (above 6 GHz) need to be adopted to provide additional spectrum. This paper investigates the characteristics of indoor corridor channels at 15 GHz. Channel measurements with a vector network analyzer in two corridors were conducted. Based on a ray-optical approach, a deterministic channel model covering both antenna and propagation characteristic is presented. The channel model is evaluated by comparing simulated results of received power and root mean square delay spread with the corresponding measurements. By removing the impact of directional antennas from the transmitter and receiver, a path …

An Overview Of Current Applications, Challenges, And Future Trends In Distributed Process-Based Models In Hydrology, Simone Fatichi, Enrique R. Vivoni, Fred L. Ogden, Valeriy Y. Ivanov, Benjamin Mirus, David Gochis, Charles W. Downer, Matteo Camporese, Jason H. Davidson, Brian Ebel, Norm Jones, Jongho Kim, Giuseppe Mascaro, Richard Niswonger, Pedro Restrepo, Riccardo Rigon, Chaopeng Shen, Mauro Sulis, David Tarboton

Faculty Publications

Process-based hydrological models have a long history dating back to the 1960s. Criticized by some as over-parameterized, overly complex, and difficult to use, a more nuanced view is that these tools are necessary in many situations and, in a certain class of problems, they are the most appropriate type of hydrological model. This is especially the case in situations where knowledge of flow paths or distributed state variables and/or preservation of physical constraints is important. Examples of this include: spatiotemporal variability of soil moisture, groundwater flow and runoff generation, sediment and contaminant transport, or when feedbacks among various Earth’s system …

A Continuous Formulation For Logical Decisions In Differential Algebraic Systems Using Mathematical Programs With Complementarity Constraints, Kody M. Powell, Ammon N. Eaton, John Hedengren, Thomas F. Edgar

Faculty Publications

This work presents a methodology to represent logical decisions in differential algebraic equation simulation and constrained optimization problems using a set of continuous algebraic equations. The formulations may be used when state variables trigger a change in process dynamics, and introduces a pseudo-binary decision variable, which is continuous, but should only have valid solutions at values of either zero or one within a finite time horizon. This formulation enables dynamic optimization problems with logical disjunctions to be solved by simultaneous solution methods without using methods such as mixed integer programming. Several case studies are given to illustrate the value of …

A Continuous Formulation For Logical Decisions In Differential Algebraic Systems Using Mathematical Programs Of Complementarity Constraints, Kody Powell, Ammon N. Eaton, John Hedengren, Thomas F. Edgar

Faculty Publications

This work presents a methodology to represent logical decisions in differential algebraic equation simulation and constrained optimization problems using a set of continuous algebraic equations. The formulations may be used when state variables trigger a change in process dynamics, and introduces a pseudo-binary decision variable, which is continuous, but should only have valid solutions at values of either zero or one within a finite time horizon. This formulation enables dynamic optimization problems with logical disjunctions to be solved by simultaneous solution methods without using methods such as mixed integer programming. Several case studies are given to illustrate the value of …

Materials Design On The Origin Of Gap States In A High-Κ/Gaas Interface, Weichao Wang, Cheng Gong, Ka Xiong, Santosh Kc, Robert Wallace, Kyeongjae Cho

Faculty Publications

Given the demand for constantly scaling microelectronic devices to ever smaller dimensions, a SiO2 gate dielectric was substituted with a higher dielectric-constant material, Hf(Zr)O2, in order to minimize current leakage through dielectric thin film. However, upon interfacing with high dielectric constant (high-κ) dielectrics, the electron mobility in the conventional Si channel degrades due to Coulomb scattering, surface-roughness scattering, remote-phonon scattering, and dielectric-charge trapping. III-V and Ge are two promising candidates with superior mobility over Si. Nevertheless, Hf(Zr)O2/III-V(Ge) has much more complicated interface bonding than Si-based interfaces. Successful fabrication of a high-quality device critically depends on understanding and engineering the bonding …

A Recommendation System For Meta-Modeling: A Meta-Learning Based Approach, Can Cui, Mengqi Hu, Jeffery D. Weir, Teresa Wu

Faculty Publications

Various meta-modeling techniques have been developed to replace computationally expensive simulation models. The performance of these meta-modeling techniques on different models is varied which makes existing model selection/recommendation approaches (e.g., trial-and-error, ensemble) problematic. To address these research gaps, we propose a general meta-modeling recommendation system using meta-learning which can automate the meta-modeling recommendation process by intelligently adapting the learning bias to problem characterizations. The proposed intelligent recommendation system includes four modules: (1) problem module, (2) meta-feature module which includes a comprehensive set of meta-features to characterize the geometrical properties of problems, (3) meta-learner module which compares the performance of instance-based …

Towards Developing Product Applications Of Thick Origami Using The Offset Panel Technique, Michael R. Morgan, Robert J. Lang, Spencer P. Magleby, Larry L. Howell

Faculty Publications

Several methods have been developed to accommodate for the use of thick materials in origami models which preserve either the model’s full range of motion or its kinematics. The offset panel technique (OPT) preserves both the range of motion and the kinematics while allowing for a great deal of flexibility in design. This work explores new possibilities for origami-based product applications presented by the OPT. Examples are included to illustrate fundamental capabilities that can be realized with thick materials such as accommodation of various materials in a design and manipulation of panel geometry resulting in an increased stiffness and strength. …

Efficacy Of Physical Layer Preamble Manipulation For Ieee 802.11a/Ac, Benjamin W. Ramsey, Jonathan D. Fuller, Christopher W. Badenhop

Faculty Publications

Wireless physical layer manipulation is a recently discovered technique for selective packet obfuscation. This process exploits the unique and proprietary nature of transceiver designs rather than manufacturing imperfections. To date, preamble manipulation has only successfully been demonstrated on low data rate transceivers operating in the2.4 GHz band. This Letter investigates the effectiveness of preamble manipulation on common 5 GHz IEEE 802.11a and IEEE 802.11ac wireless transceivers for the first time. Herein it is demonstrated that the preamble short training sequence length can be manipulated to discern among the six transceiver designs under test with greater than 99% accuracy using fewer …

Dynamic Control Of Radiative Surface Properties With Origami-Inspired Design, Rydge B. Mulford, Matthew R. Jones, Brian D. Iverson

Faculty Publications

Thermal management systems for space equipment commonly use static solutions that do not adapt to environmental changes. Dynamic control of radiative surface properties is one way to respond to environmental changes and to increase the capabilities of spacecraft thermal management systems. This paper documents an investigation of the extent to which origami-inspired surfaces may be used to control the apparent absorptivity of a reflective material. Models relating the apparent absorptivity of a radiation shield to time-dependent surface temperatures are presented. Results show that the apparent absorptivity increases with increasing fold density and indicate that origami-inspired designs may be used to …

Improved Sensitivity Mems Cantilever Sensor For Terahertz Photoacoustic Spectroscopy, Ronald A. Coutu Jr., Ivan R. Medvedev, Douglas T. Petkie

Faculty Publications

In this paper, a microelectromechanical system (MEMS) cantilever sensor was designed, modeled and fabricated to measure the terahertz (THz) radiation induced photoacoustic (PA) response of gases under low vacuum conditions. This work vastly improves cantilever sensitivity over previous efforts, by reducing internal beam stresses, minimizing out of plane beam curvature and optimizing beam damping. In addition, fabrication yield was improved by approximately 50% by filleting the cantilever’s anchor and free end to help reduce high stress areas that occurred during device fabrication and processing. All of the cantilever sensors were fabricated using silicon-on-insulator (SOI) wafers and tested in a custom …

Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall

Faculty Publications

The thermal properties of carbon nanotube- (CNT-) sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an …

Lattice Flexures: Geometries For Stiffness Reduction Of Blade Flexures, Larry L. Howell, Ezekiel G. Merriam

Faculty Publications

Reducing the motion-direction stiffness of compliant mechanisms reduces their actuation effort and simplifies associated static balancing mechanisms. This work introduces a flexure type called lattice flexures and evaluates some of their fundamental properties. Lattice flexures have a reduced bending stiffness when compared to traditional rectangular-section blade flexures of similar size. The motion-direction bending stiffness of two lattice flexure types, called X-type and V-type, are analytically derived, corroborated with finite element analysis, and validated with measurements of physical prototypes. The lattice flexure has the potential to reduce the bending stiffness of some compliant mechanisms by 60-80%, as demonstrated in devices manufactured …

Wind Plant System Engineering Through Optimization Of Layout And Yaw Control, Paul Fleming, Andrew Ning, Pieter Gebraad, Katherine Dykes

Faculty Publications

Recent research has demonstrated exciting potential for wind plant control systems to improve the cost of energy of wind plants. Wind plant controls seek to improve global wind plant performance over control systems in which each turbine optimizes only its individual performance by accounting for the way wind turbines interact through their wakes. Although these technologies can be applied to existing wind plants, it is probable that the maximum benefit would be derived by designing wind plants with these capabilities in mind. In this paper, we use system engineering approaches to perform coupled wind plant controls and position layout optimizations …