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2012

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Articles 5971 - 6000 of 6303

Full-Text Articles in Engineering

Model System Using Controlled Receptor Expression For Molecular Ultrasound Imaging Applications, Reshu Saini Jan 2012

Model System Using Controlled Receptor Expression For Molecular Ultrasound Imaging Applications, Reshu Saini

All ETDs from UAB

Ultrasound is a noninvasive, inexpensive imaging modality used to characterize biological tissues. Targeted contrast-enhanced ultrasound imaging is an emerging preclinical strategy which uses contrast agents for characterization of biological processes on a molecular level. These microbubble agents are lipid shelled micron-sized particles that have the capability to be coated with ligands such as antibodies or small peptides in order to bind to their target receptors. Molecular ultrasound imaging, using these targeted contrast agents, allows for a quantitative assessment of molecular targets with a high sensitivity. Although this technique is in preclinical research, further advances in contrast agent design and potential …

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Mechanical Analysis Of Bacterial Nanocellulose For Biomedical Applications, Joseph Mathias Schwertz Jan 2012

Mechanical Analysis Of Bacterial Nanocellulose For Biomedical Applications, Joseph Mathias Schwertz

All ETDs from UAB

Bacterial nanocellulose (BNC) is a biopolymer that has been used in a variety of applications ranging from speaker diaphragms to biomedical products. Created by micro-organisms like Gluconacetobacter xylinus, BNC is composed of long cellulose fibers in a highly crystalline hydrogel. Recent interest in BNC based materials has led to the discov-ery of several cultivation and post-processing treatments that have enabled researchers to control the mechanical and structural properties of the hydrogel. Three BNC treatments were mechanically evaluated through tensile testing. Ten-sile tests were conducted using dogbone shape test strips and a video extensometer. Phys-ical compression of a BNC hydrogels not …

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Construction Of Polynomials And Linear Weight Calculation For Weno Schemes, Jacob Alan Nelson Jan 2012

Construction Of Polynomials And Linear Weight Calculation For Weno Schemes, Jacob Alan Nelson

All ETDs from UAB

Many applications of computational fluid dynamics (CFD) require higher order spatial accuracy to resolve the flow field. A few examples of these complex flows include heat transfer problems associated with hypersonic flows, flapping wing simulations, turbo-machineries, rotorcrafts, aero-acoustic problems, and transition to turbulence. Methods being used within the CFD community to achieve higher order spatial accuracy include discontinuous Galerkin schemes, weighted essentially non-oscillatory schemes (WENO), and spectral volume (SV) schemes. Complex flow problems involving complex geometries may necessitate the use of generalized grids for the discretization of the domain. Generalized grids contain elements of multiple types and allow for a …

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Electrospun Carbon Nanofibers Decorated With Various Amounts Of Electrochemically-Inert Nickel Nanoparticles For Use As High-Performance Energy Storage Materials, Liwen Ji, Zhan Lin, Mataz Alcoutlabi, Ozan Toprakci, Yingfang Yao, Guanjie Xu, Shuli Li, Xiangwu Zhang Jan 2012

Electrospun Carbon Nanofibers Decorated With Various Amounts Of Electrochemically-Inert Nickel Nanoparticles For Use As High-Performance Energy Storage Materials, Liwen Ji, Zhan Lin, Mataz Alcoutlabi, Ozan Toprakci, Yingfang Yao, Guanjie Xu, Shuli Li, Xiangwu Zhang

Mechanical Engineering Faculty Publications

Carbon nanofibers decorated with various amounts of electrochemically-inert metallic nickel nanoparticles are synthesized through electrospinning and carbonization processes. The morphology and composition of Ni nanoparticles in carbon nanofibers are controlled by preparing different nanofiber precursors. The lithium-ion battery performance evaluations indicated that the content of electrochemically-inert Ni nanoparticles in carbon nanofibers has a great influence on the final electrochemical performance. For example, at certain Ni contents, these composite nanofibers display excellent electrochemical performance, such as high reversible capacities, good capacity retention, and excellent rate performance, when directly used as binder-free anodes for rechargeable lithium-ion batteries. However, when the Ni content …

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Microfabrication Of Conductive Polymer Nanocomposite For Sensor Applications, Chaoxuan Liu Jan 2012

Microfabrication Of Conductive Polymer Nanocomposite For Sensor Applications, Chaoxuan Liu

LSU Doctoral Dissertations

This dissertation developed novel microfabrication techniques of conductive polymer nanocomposite and utilized this material as a functional element for various physical sensor applications. Microstructures of nanocomposite were realized through novel microcontact printing and laser ablation assisted micropatterning processes. Prototype devices including large-strain strain sensor and highly-sensitive pressure sensor were demonstrated showing distinct advantages over existing technologies. The polymer nanocomposite used in this work comprised elastomer poly(dimexylsiloxane) (PDMS) as polymer matrix and multi-walled carbon nananotubes (MWCNTs) as a conductive nanofiller. To achieve uniform distribution of carbon nanotubes within the polymer, an optimized dispersion process was developed, featuring a strong organic solvent—chloroform, …

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A Thermodynamic Framework For The Modeling And Optimization Of Crystallization Processes, David John Widenski Jan 2012

A Thermodynamic Framework For The Modeling And Optimization Of Crystallization Processes, David John Widenski

LSU Doctoral Dissertations

Crystallization is a widely used chemical engineering separation unit operation process. Since this technique can produce high purity products it is used for the industrial production of many chemical compounds, such as pharmaceuticals, agrochemicals, and fine chemicals. The production of these products is a multi-million dollar industry. Any methods to improve the production of these products would be highly valued. Thus, the main objective of this work is to target model-based optimal strategies for crystallization operations specifically targeting crystal size and crystal size distribution (CSD). In particular, take the knowledge gained and translate it into an economically and practically feasible …

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Thermal Field Investigations And Applications To Integral Abutment Bridges With Frp Panels, Bo Kong Jan 2012

Thermal Field Investigations And Applications To Integral Abutment Bridges With Frp Panels, Bo Kong

LSU Doctoral Dissertations

Expansion joints are often considered as one of the most vulnerable elements affecting the sustainability of traditional jointed bridges. Over the past several decades, a new type of integral abutment bridge (IAB) has been proposed, where the joints are eliminated at the abutments and/or along the length of the bridges. Although with wide acceptances, the IABs have not been largely applied in practice. Many arguments are unsettled and there are no national design guidelines currently. Among all, the thermal behavior is one of the most concerned issues, and that, to a large extent, limits the maximum length of IABs that …

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Thermal Stress Analysis Of Jointed Plain Concrete Pavements Containing Fly Ash And Slag, Yoonseok Chung Jan 2012

Thermal Stress Analysis Of Jointed Plain Concrete Pavements Containing Fly Ash And Slag, Yoonseok Chung

LSU Doctoral Dissertations

With the current demand for Portland cement concrete (PCC) sustainability, supplementary cementitious materials (SCMs) are used in concrete mixtures. The SCMs positively impact the environmental and economic aspects of concrete mixtures and improve the mixture properties in both fresh and hardened concrete. In this research, one control and twenty-four ternary mixtures, with various combinations of fly ashes (Class C and F), slags (Grade 100 and 120), and Portland cement were fabricated. The thermal properties (coefficient of thermal expansion (CTE), thermal conductivity, and heat capacity) and mechanical properties of the selected ternary mixtures were measured at various ages. Temperature gradients were …

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System Of Systems Perspective On Risk: Towards A Unified Concept, C. Ariel Pinto, Michael K. Mcshane, Ipek Bozkurt Jan 2012

System Of Systems Perspective On Risk: Towards A Unified Concept, C. Ariel Pinto, Michael K. Mcshane, Ipek Bozkurt

Finance Faculty Publications

Many systems and projects that concern systems engineers, engineering managers, and business managers today can be defined as system of systems (SoS), which are described as ambiguous, uncertain and dynamic, among others. In addition to the traditional view on risk identification, analysis and management, the concept of risk should be considered with respect to these systems of systems. The purpose of this paper is to analyse both fundamental concepts and recent publications in system of systems, business and engineering management, as well as risk analysis, modelling, and management for the purpose of better describing the concept of risk with respect …

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Material Characterization Of Zinc Oxide In Bulk And Nanowire Form At Terahertz Frequencies, Forest Emerson Kernan Jan 2012

Material Characterization Of Zinc Oxide In Bulk And Nanowire Form At Terahertz Frequencies, Forest Emerson Kernan

Dissertations and Theses

Many new applications are being proposed and developed for use in the terahertz (THz) frequency region. Similarly, many new materials are being characterized for possible use in this area. Nanostructured forms are of particular interest since they may yield desirable properties, but they remain especially challenging to characterize. This work focuses on the characterization of zinc oxide (ZnO) in bulk and nanowire form. A method for characterizing nanostructures at THz by use of a parallel-plate waveguide (PPWG) is presented. This method is novel in that it is simple, both in theory and practice, and does not require the use of …

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Scale Invariant Object Recognition Using Cortical Computational Models And A Robotic Platform, Danny Voils Jan 2012

Scale Invariant Object Recognition Using Cortical Computational Models And A Robotic Platform, Danny Voils

Dissertations and Theses

This paper proposes an end-to-end, scale invariant, visual object recognition system, composed of computational components that mimic the cortex in the brain. The system uses a two stage process. The first stage is a filter that extracts scale invariant features from the visual field. The second stage uses inference based spacio-temporal analysis of these features to identify objects in the visual field. The proposed model combines Numenta's Hierarchical Temporal Memory (HTM), with HMAX developed by MIT's Brain and Cognitive Science Department. While these two biologically inspired paradigms are based on what is known about the visual cortex, HTM and HMAX …

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An Empirical Study Of Particulate Matter Exposure For Transit Users At Bus Stop Shelters, Adam Moore Jan 2012

An Empirical Study Of Particulate Matter Exposure For Transit Users At Bus Stop Shelters, Adam Moore

Dissertations and Theses

Congested traffic corridors in dense urban areas are key contributors to the degradation of urban air quality. While waiting at bus stops, transit patrons may be exposed to greater amounts of vehicle-based pollution, including particulate matter, due to their proximity to the roadway. Current guidelines for the location and design of bus stops do not take into account air quality or exposure considerations. This thesis provides a unique contribution to roadside air quality studies and presents an innovative method for the consideration of bus shelter placement. Exposure to roadside pollutants is estimated for transit riders waiting at three-sided bus stop …

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Distributed Solar Photovoltaic Grid Integration System : A Case Study For Performance, Ming Shen Jan 2012

Distributed Solar Photovoltaic Grid Integration System : A Case Study For Performance, Ming Shen

Dissertations and Theses

The needs to the sustainable development of electricity, energy efficiency improvement, and environment pollution reduction have favored the development of distributed generation (DG). But the problems come with increasing DG penetration in distribution networks. This thesis presents the Solar Energy Grid Integration System (SEGIS) Stage III project done by Portland General Electric (PGE), Advanced Energy, Sandia National Lab on a PGE selected distribution feeder. The feeder has six monitored commercial solar PV systems connected. The total power output from the PV systems has the potential to reach 30% of the feeder load. The author analyzes the performance of the solar …

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Digital Fabric, Sudheer Goshi Jan 2012

Digital Fabric, Sudheer Goshi

Dissertations and Theses

Continuing advances with VLSI have enabled engineers to build high performance computer systems to solve complex problems. The real-world problems and tasks like pattern recognition, speech recognition, etc. still remain elusive to the most advanced computer systems today. Many advances in the science of computer design and technology are coming together to enable the creation of the next-generation computing machines to solve real-world problems, which the human brain does with ease. One such engineering advance is the field of neuromorphic engineering, which tries to establish closer links to biology and help us investigate the problem of designing better computing machines. …

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A Fault-Tolerant Alternative To Lockstep Triple Modular Redundancy, Andrew Lockett Baldwin Jan 2012

A Fault-Tolerant Alternative To Lockstep Triple Modular Redundancy, Andrew Lockett Baldwin

Dissertations and Theses

Semiconductor manufacturing defects adversely affect yield and reliability. Manufacturers expend vast resources to reduce defects within their processes. As the minimum feature size get smaller, defects become increasingly difficult to prevent. Defects can change the behavior of a logic circuit resulting in a fault. Manufacturers and designers may improve yield, reliability, and profitability by using design techniques that make products robust even in the presence of faults. Triple modular redundancy (TMR) is a fault tolerant technique commonly used to mask faults using voting outcomes from three processing elements (PE). TMR is effective at masking errors as long as no more …

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Evolved Design Of A Nonlinear Proportional Integral Derivative (Npid) Controller, Shubham Chopra Jan 2012

Evolved Design Of A Nonlinear Proportional Integral Derivative (Npid) Controller, Shubham Chopra

Dissertations and Theses

This research presents a solution to the problem of tuning a PID controller for a nonlinear system. Many systems in industrial applications use a PID controller to control a plant or the process. Conventional PID controllers work in linear systems but are less effective when the plant or the process is nonlinear because PID controllers cannot adapt the gain parameters as needed. In this research we design a Nonlinear PID (NPID) controller using a fuzzy logic system based on the Mamdani type Fuzzy Inference System to control three different DC motor systems. This fuzzy system is responsible for adapting the …

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Silk Cryogels For Microfluidics, Christopher David Hinojosa Jan 2012

Silk Cryogels For Microfluidics, Christopher David Hinojosa

Dissertations and Theses

Silk fibroin from silkworm cocoons is found in numerous applications ranging from textiles to medical implants. Its recent adoption as a biomaterial is due to the material's strength, biocompatibility, self-assembling behavior, programmable degradability, optical clarity, and its ability to be functionalized with antibodies and proteins. In the field of bioengineering it has been utilized as a tissue scaffolding, drug delivery system, biosensor, and implantable electrode. This work suggests a new application for porous silk in a microscale chromatography column. We demonstrate in situ cryotropic polymerization of highly porous structures in microscale geometries by freezing aqueous silk with a solvent. The …

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Passive Acoustic Vessel Localization, Pasang Sherpa Suwal Jan 2012

Passive Acoustic Vessel Localization, Pasang Sherpa Suwal

Dissertations and Theses

This thesis investigates the development of a low-cost passive acoustic system for localizing moving vessels to monitor areas where human activities such as fishing, snorkeling and poaching are restricted. The system uses several off-the-shelf sensors with unsynchronized clocks where the Time Difference of Arrival (TDOA) or time delay is extracted by cross-correlation of the signal between paired sensors. The cross-correlation function uses phase correlation or Phase Transform (PHAT) which whitens the cross-spectrum in order to de-emphasize dominant frequency components. Using the locations of pairs of sensors as foci, hyperbolic equations can be defined using the time delay between them. With …

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Memristor-Based Reservoir Computing, Manjari S. Kulkarni Jan 2012

Memristor-Based Reservoir Computing, Manjari S. Kulkarni

Dissertations and Theses

In today's nanoscale era, scaling down to even smaller feature sizes poses a significant challenge in the device fabrication, the circuit, and the system design and integration. On the other hand, nanoscale technology has also led to novel materials and devices with unique properties. The memristor is one such emergent nanoscale device that exhibits non-linear current-voltage characteristics and has an inherent memory property, i.e., its current state depends on the past. Both the non-linear and the memory property of memristors have the potential to enable solving spatial and temporal pattern recognition tasks in radically different ways from traditional binary transistor-based …

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Experimental Study Of Fault Cones And Fault Aliasing, Vedanth Bilagi Jan 2012

Experimental Study Of Fault Cones And Fault Aliasing, Vedanth Bilagi

Dissertations and Theses

The test of digital integrated circuits compares the test pattern results for the device under test (DUT) to the expected test pattern results of a standard reference. The standard response is typically obtained from simulations. The test pattern and response are created and evaluated assuming ideal test conditions. The standard response is normally stored within automated test equipment (ATE). However the use of ATE is the major contributor to the test cost. This thesis explores an alternative strategy to the standard response. As an alternative to the stored standard response, the response is estimated by fault tolerant technique. The purpose …

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An Introduction To Climate Change, Geoffrey Swan Jan 2012

An Introduction To Climate Change, Geoffrey Swan

Research outputs 2012

A lecture presentation has been developed that introduces physics students to the science of climate change and its impact in society. Student feedback indicates a high level of satisfaction with the presentation.

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Low-Cost Educational Optical Coherence Tomography System For Thickness Measurmentstomography System For Thickness Measurments, Joshua Barr, Paul V. Jansz, Steven Hinckley, Graham Wild Jan 2012

Low-Cost Educational Optical Coherence Tomography System For Thickness Measurmentstomography System For Thickness Measurments, Joshua Barr, Paul V. Jansz, Steven Hinckley, Graham Wild

Research outputs 2012

We have developed an inexpensive rudimentary low coherence interferometer that can be used to measure sample thickness in the micron to mm range, and for exploring educational aspects of interferometry and optical coherence tomography.

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Developing An Educational Video For Utilising An Oscilloscope In First Year Physics, Daniel Oswald, Graham Wild, Steven Hinckley Jan 2012

Developing An Educational Video For Utilising An Oscilloscope In First Year Physics, Daniel Oswald, Graham Wild, Steven Hinckley

Research outputs 2012

We report the development of a multimedia resource designed to aid undergraduate engineering and physics students in learning the operation and functions of a Digital Storage Oscilloscope.

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Gamma Irradiation In Fibre Bragg Gratings, Desmond Baccini, Steven Hinckley, Graham Wild, Connie Banos, Justin B. Davies Jan 2012

Gamma Irradiation In Fibre Bragg Gratings, Desmond Baccini, Steven Hinckley, Graham Wild, Connie Banos, Justin B. Davies

Research outputs 2012

We report a preliminary study of gamma radiation effects on the current generation of optical fibre Bragg grating sensors, and the effects of relaxation after gamma irradiation, as a function of dose.

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Wavelength Division Multiplexing Of A Fibre Bragg Grating Sensor Using Transmit-Reflect Detection System, Gary Allwood, Graham Wild, Steven Hinckley Jan 2012

Wavelength Division Multiplexing Of A Fibre Bragg Grating Sensor Using Transmit-Reflect Detection System, Gary Allwood, Graham Wild, Steven Hinckley

Research outputs 2012

Here we have performed dense wavelength division multiplexing of a single fibre Bragg grating (FBG) sensor interrogated using a transmit-reflect detection system. The FBG was used to sense an applied ultrasonic signal.

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Optimisation Of Power Detection Interrogation Methods For Fibre Bragg Grating Sensors, Graham Wild, Steven Richardson Jan 2012

Optimisation Of Power Detection Interrogation Methods For Fibre Bragg Grating Sensors, Graham Wild, Steven Richardson

Research outputs 2012

We present a method to optimise the performance of power detection interrogation systems for fibre Bragg grating sensors. The performance of the different systems can be optimised in terms of their sensitivity and/or dynamic range.

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A Generalized Version Of An Ivantsov-Based Dendrite Growth Model Incorporating A Facility For Solute Measurement Ahead Of The Tip, Shaun Mcfadden, David Browne Jan 2012

A Generalized Version Of An Ivantsov-Based Dendrite Growth Model Incorporating A Facility For Solute Measurement Ahead Of The Tip, Shaun Mcfadden, David Browne

Articles

Extensions to the Ivantsov dendrite growth model are presented, which allow for increased solute levels in the field ahead of the dendrite tip. This model is intended for use with video-microscopy experimental results taken from synchrotron radiography sources. Ideally, the composition and composition gradient at the solid-liquid interface would be measured. However, due to the spatial resolution limitations, it is difficult to accurately measure the composition at the interface. This paper sets out an extended description of the theory where measurements ahead of the tip determine the operating conditions at the tip. This extended model of dendritic growth may be …

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Object Retrieval From Secure Unknown Interior Spaces Using Autonomous Unmanned Aerial Vehicles, John Levous, Julie Hoven, Victor Habgood, Abdulrahman Alotaibi, Brandon Ordway, Garibe Mohammed-Jones, Haole Guo, Filip Cuckov, Chung-Hao Chen Jan 2012

Object Retrieval From Secure Unknown Interior Spaces Using Autonomous Unmanned Aerial Vehicles, John Levous, Julie Hoven, Victor Habgood, Abdulrahman Alotaibi, Brandon Ordway, Garibe Mohammed-Jones, Haole Guo, Filip Cuckov, Chung-Hao Chen

Electrical & Computer Engineering Faculty Publications

This paper describes an autonomous unmanned aerial vehicle (UAV) designed to participate in the 23rd annual International Aerial Robotics Competition. The UAV is equipped with onboard sensors and a Harvard architecture 8-bit RISC microcontroller to monitor and locally control its flight telemetry. Additional sensors (and an additional microcontroller) are used for detecting and mapping of structural and environmental objects while the UAV is in flight. The microcontrollers are interfaced with wireless communication modules for transmitting flight telemetry and structural/environmental data to a ground control station that sends the UAV command and control signals required for the mission objectives. The UAV …

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Evacuee Route Choice Decisions In A Dynamic Hurricane Evacuation Context, R. Michael Robinson, Asad Khattak Jan 2012

Evacuee Route Choice Decisions In A Dynamic Hurricane Evacuation Context, R. Michael Robinson, Asad Khattak

VMASC Publications

Very high traffic volumes may lead to extensive congestion during hurricane evacuations. Evacuation planners reduce this congestion by careful planning for multiple hurricane scenarios and assignment of evacuation routes and timing. This planning may be for naught if obstructions block key roadways. An advanced traveler information system (ATIS) may be used to guide evacuees to alternate routes, but how effective will that guidance be? Should the use of alternate routes be encouraged? How are drivers likely to respond to delays and information? Will information shorten or improve the reliability of travel times in emergency conditions? Integration of a dynamic evacuation …

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Model Individualization For Real-Time Operator Functional State Assessment, Guangfan Zhang, Roger Xu, Wei Wang, Aaron A. Pepe, Feng Li, Jiang Li, Frederick Mckenzie, Tom Schnell, Nick Anderson, Dean Heitkamp Jan 2012

Model Individualization For Real-Time Operator Functional State Assessment, Guangfan Zhang, Roger Xu, Wei Wang, Aaron A. Pepe, Feng Li, Jiang Li, Frederick Mckenzie, Tom Schnell, Nick Anderson, Dean Heitkamp

Electrical & Computer Engineering Faculty Publications

Proper assessment of Operator Functional State (OFS) and appropriate workload modulation offer the potential to improve mission effectiveness and aviation safety in both overload and under-load conditions. Although a wide range of research has been devoted to building OFS assessment models, most of the models are based on group statistics and little or no research has been directed towards model individualization, i.e., tuning the group statistics based model for individual pilots. Moreover, little emphasis has been placed on monitoring whether the pilot is disengaged during low workload conditions. The primary focus of this research is to provide a real-time engagement …

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