Engineering Commons^™

Fracture Detection In Traumatic Pelvic Ct Images, Jie Wu, Pavani Davuluri, Kevin R. Ward, Charles Cockrell, Rosalyn H. Hargraves, Kayvan Najarian

Computer Science Publications

Fracture detection in pelvic bones is vital for patient diagnostic decisions and treatment planning in traumatic pelvic injuries. Manual detection of bone fracture from computed tomography (CT) images is very challenging due to low resolution of the images and the complex pelvic structures. Automated fracture detection from segmented bones can significantly help physicians analyze pelvic CT images and detect the severity of injuries in a very short period. This paper presents an automated hierarchical algorithm for bone fracture detection in pelvic CT scans using adaptive windowing, boundary tracing, and wavelet transform while incorporating anatomical information. Fracture detection is performed on …

An Automated Optimal Engagement And Attention Detection System Using Electrocardiogram, Ashwin Belle, Rosalyn H. Hargraves, Kayvan Najarian

Computer Science Publications

This research proposes to develop a monitoring system which uses Electrocardiograph (ECG) as a fundamental physiological signal, to analyze and predict the presence or lack of cognitive attention in individuals during a task execution. The primary focus of this study is to identify the correlation between fluctuating level of attention and its implications on the cardiac rhythm recorded in the ECG. Furthermore, Electroencephalograph (EEG) signals are also analyzed and classified for use as a benchmark for comparison with ECG analysis. Several advanced signal processing techniques have been implemented and investigated to derive multiple clandestine and informative features from both these …

Mineralization Potential Of Electrospun Pdo-Hydroxyapatite-Fibrinogen Blended Scaffolds, Isaac Rodriguez, Parthasarathy A. Madurantakam, Jennifer M. Mccool, Scott A. Sell, Hu Yang, Peter C. Moon, Gary L. Bowlin

Biomedical Engineering Publications

The current bone autograft procedure for cleft palate repair presents several disadvantages such as limited availability, additional invasive surgery, and donor site morbidity. The present preliminary study evaluates the mineralization potential of electrospun polydioxanone:nano-hydroxyapatite : fibrinogen (PDO : nHA : Fg) blended scaffolds in different simulated body fluids (SBF). Scaffolds were fabricated by blending PDO : nHA : Fg in the following percent by weight ratios: 100 : 0 : 0, 50 : 25 : 25, 50 : 50 : 0, 50 : 0 : 50, 0 : 0 : 100, and 0 : 50 : 50. Samples were immersed …

A Preliminary Study On The Potential Of Manuka Honey And Platelet-Rich Plasma In Wound Healing, Scott A. Sell, Patricia Wolfe, Andrew J. Spence, Isaac Rodriguez, Jennifer M. Mccool, Rebecca L. Petrella, Koyal Garg, Jeffery J. Ericksen, Gary L. Bowlin

Biomedical Engineering Publications

Aim. The purpose of this study was to determine the in vitro response of cells critical to the wound healing process in culture media supplemented with a lyophilized preparation rich in growth factors (PRGF) and Manuka honey. Materials and Methods. This study utilized cell culture media supplemented with PRGF, as well as whole Manuka honey and the medical-grade Medihoney (MH), a Manuka honey product. The response of human fibroblasts (hDF), macrophages, and endothelial cells (hPMEC) was evaluated, with respect to cell proliferation, chemotaxis, collagen matrix production, and angiogenic potential, when subjected to culture with media containing PRGF, MH, Manuka honey, …

Information Processing With Electron Spins, Supriyo Bandyopadhyay

Electrical and Computer Engineering Publications

Information processors process information in a variety of ways. The human brain processes information through a highly interconnected system of neurons and synapses, while a digital computer processes information by having a binary switch toggle on and off in response to a stream of binary bits. The “switch” is the most primitive unit of the modern computer. The better it is (faster, more energy efficient, more reliable, etc.), the more advanced is the computer hardware. Energy efficiency, however, is more important than any other attribute, not so much because energy is costly, but because too much energy dissipation prevents increasing …

Metastable State In A Shape-Anisotropic Single-Domain Nanomagnet Subjected To Spin-Transfer-Torque, Kuntal Roy, Supriyo Bandyopadhyay, Jayasimha Atulasimha

Electrical and Computer Engineering Publications

We predict the existence of a metastable magnetization state in a single-domain nanomagnet with uniaxial shape anisotropy. It emerges when a spin-polarized current, which delivers a spin-transfer-torque possessing a field-like component, is injected into the nanomagnet. At a metastable state, the internal torque due to nanomagnet's shape anisotropy cancels the externally applied spin-transfer-torque and hence the nettorque acting on the magnetization becomes zero. Therefore, it prevents spin-transfer-torque from switching the magnetization from one stable state along the easy axis to the other, even in the presence of room-temperature thermal fluctuations.

Degradation And Phase Noise Of Inaln/Aln/Gan Heterojunction Field Effect Transistors: Implications For Hot Electron/Phonon Effects, C. Y. Zhu, M. Wu, C. Kayis, F. Zhang, X. Li, R. A. Ferreyra, A. Matulionis, Vitaliy Avrutin, Umit Ozgur, Hadis Morkoc

Electrical and Computer Engineering Publications

In_15.7%Al_84.3%N/AlN/GaN heterojunctionfield effect transistors have been electrically stressed under four different bias conditions: on-state-low-field stress, reverse-gate-bias stress, off-state-high-field stress, and on-state-high-field stress, in an effort to elaborate on hot electron/phonon and thermal effects. DC current and phase noise have been measured before and after the stress. The possible locations of the failures as well as their influence on the electrical properties have been identified. The reverse-gate-bias stress causes trap generation around the gate area near the surface which has indirect influence on the channel. The off-state-high-field stress and the on-state-high-field stress induce deterioration of the channel, …

Optical And Structural Studies Of Homoepitaxially Grown M-Plane Gan, S. Khromov, B. Monemar, Vitaliy Avrutin, Xing Li, Hadis Morkoç, L. Hultman, G. Pozina

Electrical and Computer Engineering Publications

Cathodoluminescence(CL) and transmission electron microscopy studies of homoepitaxiallygrownm-plane Mg-doped GaN layers are reported. Layers contain basal plane and prismatic stacking faults (SFs) with ∼10⁶cm⁻¹ density. Broad emission peaks commonly ascribed to SFs were found to be insignificant in these samples. A set of quite strong, sharp lines were detected in the same spectral region of 3.36–3.42 eV. The observed peaks are tentatively explained as excitons bound to some impurity defects, which can also be related to SFs. Donor-acceptor pair (DAP) recombination involving Si or O and Mg was ruled out by fitting DAP energies and …

Anisotropy Of Free-Carrier Absorption And Diffusivity In M-Plane Gan, P. Ščajev, K. Jarašiūnas, U. Ozgur, Hadis Morkoç, J. Leach, T. Paskova

Electrical and Computer Engineering Publications

Polarization-dependent free-carrier absorption (FCA) in bulk m-plane GaN at 1053 nm revealed approximately 6 times stronger hole-related absorption for E⊥c than for E||c probe polarization both at low and high carrier injection levels. In contrast, FCA at 527 nm was found isotropic at low injection levels due to electron resonant transitions between the upper and lower conduction bands, whereas the anisotropic impact of holes was present only at high injection levels by temporarily blocking electron transitions. Carrier transport was also found to be anisotropic under two-photon excitation, with a ratio of 1.17 for diffusivity perpendicular and parallel to the c-axis.

Improved Quantum Efficiency In Ingan Light Emitting Diodes With Multi-Double-Heterostructure Active Regions, X. Li, Serdal Okur, F. Zhang, S. A. Hafiz, Vitaliy Avrutin, Umit Ozgur, Hadis Morkoç, K. Jarašiūnas

Electrical and Computer Engineering Publications

InGaN light emitting diodes(LEDs) with multiple thin double-heterostrucutre (DH) active regions separated by thin and low energy barriers were investigated to shed light on processes affecting the quantum efficiency and means to improve it. With increasing number of 3 nm-thick DH active layers up to four, the electroluminescence efficiency scaled nearly linearly with the active region thickness owing to reduced carrier overflow with increasing total thickness, showing almost no discernible efficiency degradation at high injection levels up to the measured current density of 500 A/cm². Comparison of the resonant excitation dependent photoluminescence measurements at 10 K and room …

Impurity Distribution And Microstructure Of Ga-Doped Zno Films Grown By Molecular Beam Epitaxy, A. V. Kvit, A. B. Yankovich, V. Avrutin, H. Liu, N. Izyumskaya, Ü. H. Özgür, H. Morkoç, P. M. Voyles

Electrical and Computer Engineering Publications

We report microstructural characterization of heavily Ga-doped ZnO (GZO) thin films on GaN and sapphire by aberration-corrected scanning transmission electron microscopy. Growth under oxygen-rich and metal-rich growth conditions leads to changes in the GZO polarity and different extended defects. For GZO layers on sapphire, the primary extended defects are voids, inversion domain boundaries, and low-angle grain boundaries. Ga doping of ZnO grown under metal-rich conditions causes a switch from pure oxygen polarity to mixed oxygen and zinc polarity in small domains. Electron energy loss spectroscopy and energy dispersive spectroscopy spectrum imaging show that Ga is homogeneous, but other residual impurities …

Donor Behavior Of Sb In Zno, H. Y. Liu, N. Izyumskaya, Vitaliy Avrutin, Ü. Özgür, A. B. Yankovich, A. V. Kvit, P. M. Voyles, H. Morkoç

Electrical and Computer Engineering Publications

Electrical behavior of Sb in ZnO:Sb layers doped in a wide concentration range was studied using temperature dependent Hall effect measurements. The layers were grown by plasma-enhanced molecular beam epitaxy, and the Sb concentration was changed by varying the Sb flux, resulting in electron concentrations in the range of 10¹⁶ to nearly 10²⁰ cm⁻³. Upon annealing, the electron concentration increased slightly and more notable was that the electron mobility significantly improved, reaching a room-temperature value of 110 cm²/V s and a low-temperature value of 145 cm²/V s, close to the maximum of …

Energy Dissipation And Switching Delay In Stress-Induced Switching Of Multiferroic Nanomagnets In The Presence Of Thermal Fluctuations, Kuntal Roy, Supriyo Bandyopadhyay, Jayasimha Atulasimha

Electrical and Computer Engineering Publications

Switching the magnetization of a shape-anisotropic 2-phase multiferroic nanomagnet with voltage-generated stress is known to dissipate very little energy (<1 aJ for a switching time of ∼0.5 ns) at 0 K temperature. Here, we show by solving the stochastic Landau-Lifshitz-Gilbert equation that switching can be carried out with ∼100% probability in less than 1 ns while dissipating less than 1.5 aJ at room temperature. This makes nanomagnetic logic and memory systems, predicated on stress-induced magnetic reversal, one of the most energy-efficient computing hardware extant. We also study the dependence of energy dissipation, switching delay, and the critical stress needed to switch, on the rate at which stress on the nanomagnet is ramped up or down.

Impact Of Active Layer Design On Ingan Radiative Recombination Coefficient And Led Performance, X. Li, S. Okur, F. Zhang, V. Avrutin, Ü. Özgür, H. Morkoç, S. M. Hong, S. H. Yen, T. C. Hsu, A. Matulionis

Electrical and Computer Engineering Publications

The relative roles of radiative and nonradiative processes and the polarization field on the light emission from blue (∼425 nm) InGaN light emitting diodes (LEDs) have been studied. Single and multiple double heterostructure (DH) designs have been investigated with multiple DH structures showing improved efficiencies. Experimental results supported by numerical simulations of injection dependent electron and hole wavefunction overlap and the corresponding radiative recombination coefficients suggest that increasing the effective active region thickness by employing multiple InGaN DH structures separated by thin and low barriers is promising for LEDs with high efficiency retention at high injection. The use of thin …

Hexagonal-Based Pyramid Void Defects In Gan And Ingan, A. B. Yankovich, A. V. Kvit, X. Li, F. Zhang, V. Avrutin, H. Y. Liu, N. Izyumskaya, Ü. Özgür, H. Morkoç, P. M. Voyles

Electrical and Computer Engineering Publications

We report a void defect in gallium nitride (GaN) and InGaN, revealed by aberration-corrected scanning transmission electron microscopy (STEM). The voids are pyramids with symmetric hexagonal {0001} base facets and {101¯1} side facets. Each pyramid void has a dislocation at the peak of the pyramid, which continues up along the [0001] growth direction to the surface. Some of the dislocations are hexagonal open core screw dislocations with {101¯0} side facets, varying lateral widths, and varying degrees of hexagonal symmetry. STEM electron energy loss spectroscopy spectrum imaging showed a large C concentration inside the void and on the void surfaces. There …

Carrier Dynamics In Bulk Gan, Patrick Ščajev, Kęstutis Jarašiūnas, Serdal Okur, Ümit Özgür, Hadis Morkoç

Electrical and Computer Engineering Publications

Carrier dynamics in hydride vapor phase epitaxy grown bulk GaN with very low density of dislocations, 5–8 × 10⁵ cm⁻², have been investigated by time-resolved photoluminescence (PL), free carrier absorption, and light-induced transient grating techniques in the carrier density range of 10¹⁵ to ∼10¹⁹ cm⁻³ under single and two photon excitation. For two-photon carrier injection to the bulk (527 nm excitation), diffusivity dependence on the excess carrier density revealed a transfer from minority to ambipolar carrier transport with the ambipolar diffusion coefficient D _a saturating at 1.6 cm²/s at room temperature. An …

Electron Scattering Mechanisms In Gzo Films Grown On A-Sapphire Substrates By Plasma-Enhanced Molecular Beam Epitaxy, H. Y. Liu, V. Avrutin, N. Izyumskaya, Ü. Özgür, A. B. Yankovich, A. V. Kvit, P. M. Voyles, H. Morkoç

Electrical and Computer Engineering Publications

We report on the mechanisms governing electron transport using a comprehensive set of ZnO layers heavily doped with Ga (GZO) grown by plasma-enhanced molecular-beam epitaxy on a-plane sapphire substrates with varying oxygen-to-metal ratios and Ga fluxes. The analyses were conducted by temperature dependent Hall measurements which were supported by microstructural investigations as well. Highly degenerate GZO layers with n > 5 × 10²⁰ cm⁻³ grown under metal-rich conditions (reactive oxygen-to-metal ratio c-direction. For highly conductive GZO layers, ionized-impurity scattering with almost no compensation is the dominant mechanism limiting the mobility in the temperature range from 15 to 330 K …

Structural And Optical Quality Of Gan Grown On Sc2o3/Y2o3/Si(111), L. Tarnawska, P. Zaumseil, M. A. Schubert, S. Okur, U. Ozgur, H. Morkoç, R. Paszkiewicz, P. Storck, T. Schroeder

Electrical and Computer Engineering Publications

Thick (∼900 nm) GaN layers were grown by molecular beam epitaxy on cost-effective Sc₂O₃/Y₂O₃/Si(111) substrates and characterized by x-ray diffraction and photoluminescence. Samples grown in Ga-rich condition show superior structural and optical quality with reduced density of cubic GaN inclusions within the hexagonal matrix and a relatively strong photoluminescence emission at 3.45 eV at 10 K. Cubic inclusions are formed in the initial growth stage and their concentration is reduced with increasing film thickness and after rapid thermal annealing.

Preparing Engineers For Service, Mike Foster, Gary Spivey

Faculty Publications - Department of Electrical Engineering and Computer Science

George Fox University has a strong service mentality. As the result of the university’s “Serve Day” at the Oregon School for the Blind, faculty members developed a passion to connect engineering students with service opportunities that require a technical solution. In the spring of 2010, the engineering department initiated a course sequence required for all engineering students. The program affiliated with the EPICS program (started at Purdue University) and utilized much of their course material for documenting the design process.

Students’ initial excitement for the course waned as they began to feel burdened by the large documentation requirements; the instructors …

Defining, Teaching, And Assessing Engineering Design Skills, Nikos J. Mourtos

Faculty Publications

The paper discusses a systematic approach for defining, teaching, and assessing engineering design skills. Although the examples presented in the paper are from the field of aerospace engineering, the principles apply to engineering design in general. What makes the teaching of engineering design particularly challenging is that the necessary skills and attributes are both technical and non-technical and come from the cognitive as well as the affective domains. Each set of skills requires a different approach to teach and assess. Implementing a variety of approaches for a number of years at SJSU has shown that it is just as necessary …

Influence Of Personality On A Senior Project Combining Innovation And Entrepreneurship, Jinny Rhee, David W. Parent, Clifton M. Oyamot

Faculty Publications

No abstract provided.

A New Framework For Distributed Detection With Conditionally Dependent Observations, Hao Chen, Biao Chen, Pramod Varshney

Electrical Engineering and Computer Science - All Scholarship

Distributed detection with conditionally dependent observations is known to be a challenging problem in decentralized inference. This paper attempts to make progress on this problem by proposing a new framework for distributed detection that builds on a hierarchical conditional independence model. Through the introduction of a hidden variable that induces conditional independence among the sensor observations, the proposed model unifies distributed detection with dependent or independent observations. This new framework allows us to identify several classes of distributed detection problems with dependent observations whose optimal decision rules resemble the ones for the independent case. The new framework induces a decoupling …

Comprehensive Solution To Scattering By Bianisotropic Objects Of Arbitrary Shape, Chong Mei, Moamer Hasanovic, Jay K. Lee, E. Arvas

Electrical Engineering and Computer Science - All Scholarship

This paper presents a method of moments (MoM) solution for the problems of electromagnetic scattering by inhomogeneous three- dimensional bianisotropic scatterers of any shape. The electromagnetic response of bianisotropy has been described by the constitutive relations of the most general form composed of four 3 £ 3 matrices or tensors. The volume equivalence principle is used to obtain a set of mixed potential formulations for a proper description of the original scattering problem. Here, the total ¯elds are separated into the incident ¯elds and the scattered ¯elds. The scattered ¯elds are related to the electric and magnetic potentials which are …

Sensing As A Service: A Cloud Computing System For Mobile Phone Sensing, Xiang Xiang Sheng, Xuejie Xiao, Jian Tang, Guoliang Xue

Electrical Engineering and Computer Science - All Scholarship

Sensors on (or attached to) mobile phones can enable attractive sensing applications in different domains such as environmental monitoring, social networking, healthcare, etc. We introduce a new concept, Sensing-as-a-Service (S2aaS), i.e., providing sensing services using mobile phones via a cloud computing system. An S2aaS cloud should meet the following requirements:

1) It must be able to support various mobile phone sensing applications on different smartphone platforms.

2) It must be energy-efficient. 3) It must have effective incentive mechanisms that can be used to attract mobile users to participate in sensing activities. In this paper, we identify unique challenges of designing …

Model-Based Approach To Account For Rhe Variation Of Primary Voc Emissions Over Time In The Identification Of Indoor Voc Sources, Kwanghoon Han, Jensen S. Zhang, Pawel Wargocki, Henrik N. Knudsen, Pramod K. Varshney, Bing Guo

Mechanical and Aerospace Engineering - All Scholarship

The study objectives were to improve the understanding of the long-term variation of VOC emission chromatograms of building materials and to develop a method to account for this variation in the identification of individual sources of VOC emissions. This is of importance for the application of the source identification method since materials age over time in real indoor environments. The method is based on the mixed air sample measurements containing pollutants from multiple aged materials and the emission signatures of individual new materials determined by PTR-MS. Three emission decay source models were employed and evaluated for their ability to track …

A Threshold-Based Approach To Calorimetry In Helium Droplets: Measurement Of Binding Energies Of Water Clusters, William K. Lewis, Barbara A. Harruff-Miller, Michael A. Gord, Joseph R. Gord, Elena A. Guliants, Christopher E. Bunker

Electrical and Computer Engineering Faculty Publications

Helium dropletbeam methods have emerged as a versatile technique that can be used to assemble a wide variety of atomic and molecular clusters. We have developed a method to measure the binding energies of clusters assembled in helium droplets by determining the minimum droplet sizes required to assemble and detect selected clusters in the spectrum of the dopeddropletbeam. The differences in the droplet sizes required between the various multimers are then used to estimate the incremental binding energies. We have applied this method to measure the binding energies of cyclic waterclusters from the dimer to the tetramer. We obtain measured …

Mid-Lake Plateau 2012 Data, Grand Valley State University

Data

Data set concerning the 2012 season with the buoy located at the Mid-Lake Plateau about 35 miles west of Muskegon, MI.

Non-Isothermal Cool Flames In Unstirred Static Reactors: A Compressible Model With Global Kinetics, Michael R. Foster, Howard Pearlman

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

A compressible model is developed with kinetics based on the Wang–Mou five-step global kinetic scheme and used to evaluate the temperature, concentration, and velocity fields characteristic of low temperature combustion in unstirred static reactors. This work relaxes the assumption of small exothermicity that enabled prior studies to employ the Boussinesq approximation, valid for cases where BT << 1, i.e., slow reactions and cool flames. In this study, the range of validity of the model is extended to cases with large temperature excursions, including multi-stage ignition. For the weakly exothermic cases considered, including modes of slow reaction and cool flames, the Boussinesq approximation is completely adequate. However, it overpredicts the density change and underpredicts the ignition delay time for high-temperature ignitions. Qualitative comparison with experimental results acquired at microgravity conditions are also discussed.

Quantification Of Collagen Organization Using Fractal Dimensions And Fourier Transforms, Kayt E. Frisch, Sarah E. Duenwald-Kuehl, Hirohito Kobayashi, Connie S. Chamberlain, Roderic S. Lakes, Ray Vanderby Jr.

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Collagen fibers and fibrils that comprise tendons and ligaments are disrupted or damaged during injury. Fibrillogenesis during healing produces a matrix that is initially quite disorganized, but remodels over time to resemble, but not replicate, the original roughly parallel microstructure. Quantification of these changes is traditionally a laborious and subjective task. In this work we applied two automated techniques, fast Fourier transformation (FFT) and fractal dimension analysis (FA) to quantify the organization of collagen fibers or fibrils. Using multi-photon images of collagen fibers obtained from rat ligament we showed that for healing ligaments, FA differentiates more clearly between the different …

Encyclopedia Of Mathematics And Society: 'Engineering Design', Kimberly Edginton Bigelow

Mechanical and Aerospace Engineering Faculty Publications

Engineers design everything from automobiles and bridges to prosthetic limbs and sporting equipment. Designing is different from simply building in that it requires the adherence to a very systematic, yet iterative, process known as the “engineering design process.” This process is to engineers what the scientific method is to scientists-guiding steps that help ensure that the end result is the best it can be. When a new product is created without following the steps of the engineering design process, there is a higher likelihood that the product designed will lack some important aspect: the end product may not appropriately account …