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Articles 100021 - 100050 of 198032

Full-Text Articles in Engineering

Recent Advances In Optical Spectroscopic And Imaging Methods For Medicine And Biology, Yu Shang, Zhiyu Qian, Rickson C. Mesquita, Mathieu Dehaes Jan 2016

Recent Advances In Optical Spectroscopic And Imaging Methods For Medicine And Biology, Yu Shang, Zhiyu Qian, Rickson C. Mesquita, Mathieu Dehaes

Biomedical Engineering Faculty Publications

No abstract provided.

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An Autoencoder-Based Image Descriptor For Image Matching And Retrieval, Chenyang Zhao Jan 2016

An Autoencoder-Based Image Descriptor For Image Matching And Retrieval, Chenyang Zhao

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Local image features are used in many computer vision applications. Many point detectors and descriptors have been proposed in recent years; however, creation of effective descriptors is still a topic of research. The Scale Invariant Feature Transform (SIFT) developed by David Lowe is widely used in image matching and image retrieval. SIFT detects interest points in an image based on Scale-Space analysis, which is invariant to change in image scale. A SIFT descriptor contains gradient information about an image patch centered at a point of interest. SIFT is found to provide a high matching rate, is robust to image transformations; …

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Use Of Eeg To Understand Brain Intensity In Engineering Students Using A Stem Educational Mobile Application, Kevin Hatcher Jan 2016

Use Of Eeg To Understand Brain Intensity In Engineering Students Using A Stem Educational Mobile Application, Kevin Hatcher

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In the first two years of undergraduate work in engineering, students are taught concepts such as physics, electronics, and most importantly calculus. It is especially important for students to get a better grasp on foundational math concepts, such as calculus in the beginning or they will be overwhelmed by the workload to come. The focus of this research was to understand how students learning calculus, could benefit from an augmented-educational mobile application. In the study students were measured with electroencephalography (EEG) measurements utilized by the Emotive EPOC® as they attempted to solve different limit themed problems in order to determine …

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Locally Optimized Covariance Kriging For Non-Stationary System Responses, Daniel Lee Clark Jr. Jan 2016

Locally Optimized Covariance Kriging For Non-Stationary System Responses, Daniel Lee Clark Jr.

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In this thesis, the Locally-Optimized Covariance (LOC) Kriging method is developed. This method represents a flexible surrogate modeling approach for approximating a non-stationary Kriging covariance structures for deterministic responses. The non-stationary covariance structure is approximated by aggregating multiple stationary localities. The aforementioned localities are determined to be statistically significant utilizing the Non-Stationary Identification Test. This methodology is applied to various demonstration problems including simple one and two-dimensional analytical cases, a deterministic fatigue and creep life model, and a five-dimensional fluid-structural interaction problem. The practical significance of LOC-Kriging is discussed in detail and is directly compared to stationary Kriging considering computational …

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Analyzing Cognitive Workload Through Eye-Related Measurements: A Meta-Analysis, Melissa Patricia Coral Jan 2016

Analyzing Cognitive Workload Through Eye-Related Measurements: A Meta-Analysis, Melissa Patricia Coral

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Understanding cognitive workload has become a vital topic for researchers in developing future systems. Existing research has investigated the use of physiological measurements of the eye with cognitive workload, though a quantitative synthesis has yet to be performed. A meta-analysis was conducted to examine the effects of cognitive workload on eye-related measurements. The objective of this meta-analysis is not to determine a difference between the levels of workload, but to identify reliable measurements. Measurements through blinks, saccades, pupils, and fixations were examined. Twenty-two studies, contributing to a total of sixty entries, met the appropriate inclusion criteria for the meta-analysis. Findings …

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Extension Of Multivariate Analyses To The Field Of Microbial Ecology, Vijay Shankar Jan 2016

Extension Of Multivariate Analyses To The Field Of Microbial Ecology, Vijay Shankar

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Ground-breaking advancements in molecular and analytical techniques in the past decade have enabled researchers to accumulate data at an extraordinary rate. Especially in the field of microbial ecology, the introduction of technologies such as high-throughput sequencing, quantitative microarrays, nuclear magnetic resonance and mass spectrometry has led to the interrogation of diverse and previously unexplored microbial communities at unparalleled depth. Analysis and interpretation of patterns within datasets acquired with such high-throughput methods require powerful statistical approaches. A class of such techniques called multivariate statistical analyses is an excellent choice for analysis of complex microbiota-related datasets. This field of statistics is constantly …

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Thermoelectric Transport And Energy Conversion Using Novel 2d Materials, Luke J. Wirth Jan 2016

Thermoelectric Transport And Energy Conversion Using Novel 2d Materials, Luke J. Wirth

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Nanomaterials hold great promise for applications in thermal management and thermoelectric power generation. Defects in these are important as they are generally inevitably introduced during fabrication or intentionally engineered to control the properties of the nanomaterials. Here, we investigate how phonon-contributed thermal conductance in narrow graphene, boron nitride (BN), and silicene nanoribbons (NRs), responds to the presence of a vacancy defect and the corresponding geometric distortion, from first principles using the non-equilibrium Green's function method. Analyses are made of the geometries, phonon conductance coefficients, and local densities of states (LDOS) of pristine and defected nanoribbons. It is found that hydrogen …

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Intelligent Caching To Mitigate The Impact Of Web Robots On Web Servers, Howard Nathan Rude Jan 2016

Intelligent Caching To Mitigate The Impact Of Web Robots On Web Servers, Howard Nathan Rude

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With an ever increasing amount of data that is shared and posted on the Web, the desire and necessity to automatically glean this information has led to an increase in the sophistication and volume of software agents called web robots or crawlers. Recent measurements, including our own across the entire logs of Wright State University Web servers over the past two years, suggest that at least 60\% of all requests originate from robots rather than humans. Web robots display different statistical and behavioral patterns in their traffic compared to humans, yet present Web server optimizations presume that traffic exhibits predominantly …

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Performance Evaluation And Improvement Of Wireless Amplify-And-Forward Cooperative-Based Systems Under Nodes Mobility And Imperfect Csi Estimation Impacts, Yazid Khattabi Jan 2016

Performance Evaluation And Improvement Of Wireless Amplify-And-Forward Cooperative-Based Systems Under Nodes Mobility And Imperfect Csi Estimation Impacts, Yazid Khattabi

Electronic Theses and Dissertations

Cooperative communication techniques have been introduced in wireless networks to achieve spacial diversity-gain via the readiness of multiple users (via relays) to assist a source forwarding its data to a final destination. Cooperative communication techniques have shown their capability in improving system reliability and extending coverage area, and hence, it is believable that they will act as a promising technology for the coming fifth-generation (5G). Nevertheless, most existing work reported in literature on performance studies of wireless cooperative-based systems are based on the assumptions that the multipath fading channels among systems cooperating nodes are quasi-static (i.e., fading channels coefficients are …

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Using Case-Based Reasoning For Simulation Modeling In Healthcare, Khaled Alshareef Jan 2016

Using Case-Based Reasoning For Simulation Modeling In Healthcare, Khaled Alshareef

Electronic Theses and Dissertations

The healthcare system is always defined as a complex system. At its core, it is a system composed of people and processes and requires performance of different tasks and duties. This complexity means that the healthcare system has many stakeholders with different interests, resulting in the emergence of many problems such as increasing healthcare costs, limited resources and low utilization, limited facilities and workforce, and poor quality of services. The use of simulation techniques to aid in solving healthcare problems is not new, but it has increased in recent years. This application faces many challenges, including a lack of real …

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Smart Grid Demonstration: Distributed Active And Reactive Power Control, Siddarth Vellakovil Rajamani Jan 2016

Smart Grid Demonstration: Distributed Active And Reactive Power Control, Siddarth Vellakovil Rajamani

Electronic Theses and Dissertations

The present infrastructure of energy delivery was designed over 60 years ago with the goal to be centralized. However, it is aging and is under-utilized, which will potentially limit the world's ability to achieve its energy objective. The lack of vibrant control on the grid makes it difficult to stop cascading power failure, and to achieve high penetration of renewable energy resources, such as wind and solar thus resulting in grid instability. A decentralized and distributed control mechanism implemented with a definite communication protocol solves the issues mentioned above. The electric power grid going into the future is expected to …

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Fundamental Understanding Of Interactions Among Flow, Turbulence, And Heat Transfer In Jet Impingement Cooling, Md. Jahed Hossain Jan 2016

Fundamental Understanding Of Interactions Among Flow, Turbulence, And Heat Transfer In Jet Impingement Cooling, Md. Jahed Hossain

Electronic Theses and Dissertations

The flow physics of impinging jet is very complex and is not fully understood yet. The flow field in an impingement problem comprised of three different distinct regions: a free jet with a potential core, a stagnation region where the velocity goes to zero as the jet impinges onto the wall and a creation of wall jet region where the boundary layer grows radially outward after impinging. Since impingement itself is a broad topic, effort is being made in the current study to narrow down on three particular geometric configurations (a narrow wall, an array impingement configuration and a curved …

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Transformation Model With Constraints For High Accuracy Of 2d-3d Building Registration In Aerial Imagery, Guoqing Zhou, Qingli Luo, Wenhan Xie, Tao Yue, Jingjin Huang, Yuzhong Shen Jan 2016

Transformation Model With Constraints For High Accuracy Of 2d-3d Building Registration In Aerial Imagery, Guoqing Zhou, Qingli Luo, Wenhan Xie, Tao Yue, Jingjin Huang, Yuzhong Shen

Computational Modeling & Simulation Engineering Faculty Publications

This paper proposes a novel rigorous transformation model for 2D-3D registration to address the difficult problem of obtaining a sufficient number of well-distributed ground control points (GCPs) in urban areas with tall buildings. The proposed model applies two types of geometric constraints, co-planarity and perpendicularity, to the conventional photogrammetric collinearity model. Both types of geometric information are directly obtained from geometric building structures, with which the geometric constraints are automatically created and combined into the conventional transformation model. A test field located in downtown Denver, Colorado, is used to evaluate the accuracy and reliability of the proposed method. The comparison …

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A Microfluidic-Based Tactile Sensor For Palpating Mice Tumor Tissues, Yichao Yang, Garett Johnson, Dean Krusienski, Siqi Guo, Cheng Lin, Zhili Hao Jan 2016

A Microfluidic-Based Tactile Sensor For Palpating Mice Tumor Tissues, Yichao Yang, Garett Johnson, Dean Krusienski, Siqi Guo, Cheng Lin, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

In light of the need of tissue palpation for Robotics-assisted Minimally Invasive Surgery (RMIS), this paper presents a microfluidic-based tactile sensor for palpating mice tissues for tumor localization. The core of the sensor is a 3x3 sensing-plate/transducer array built into a single polydimethylsiloxane (PDMS) microstructure, with a transducer spacing of 3.75mmx1.5mm. Mounted on a robot, the sensor is pressed against a tissue region with a pre-defined indentation depth pattern, and consequently the stiffness distribution across the tissue region translates to the deflection distribution of the sensing-plate array and is captured by the transducer array underneath as resistance changes. Thus, the …

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Forced Convection Cooling Of Electric Motors Using Enhanced Surfaces, Mohammed Almaghrabi Jan 2016

Forced Convection Cooling Of Electric Motors Using Enhanced Surfaces, Mohammed Almaghrabi

Electronic Theses and Dissertations

Electric motors are extensively engaged in industrial and commercial applications such as electrical cars, energy-conversion systems, elevators, and actuators for aircrafts. Due to the significant internal heat generation, it is usually a challenge to design and manufacture high power density, high reliability, and low cost electric motors with superior performance. One of the efficient ways to dissipate the heat generated in the electrical motor is by using extended surfaces (i.e. heat sinks). These surfaces are extruded from the motor casing and air is forced though them by a cooling fan. This cooling approach is simple to be implemented and has …

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Structural Health Monitoring Of Composite Overwrapped Pressure Vessels, Luca Letizia Jan 2016

Structural Health Monitoring Of Composite Overwrapped Pressure Vessels, Luca Letizia

Honors Undergraduate Theses

This work is focusing to study the structural behavior of Composite Overwrapped Pressure Vessels (COPVs). These COPVs are found in many engineering applications. In the aerospace field, they are installed onto spaceships and aid the reorientation of the spacecraft in very far and airless, therefore frictionless, orbits to save energy and fuel. The intent of this research is to analyze the difference in performance of both perfectly intact and purposely damaged tanks. Understanding both the source and location of a structural fault will help NASA engineers predict the performance of COPVs subject to similar conditions, which could prevent failures of …

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Smart Material Actuation And Morphing For Unmanned Aircraft Systems, Caio H. Da Silva Lima Jan 2016

Smart Material Actuation And Morphing For Unmanned Aircraft Systems, Caio H. Da Silva Lima

Honors Undergraduate Theses

The intent of this thesis is to outline the design, analysis, and characterization of an axially compressed piezocomposite actuator and, in particular, to determine the correlation and accuracy of two models used to predict deflection of an axially compressed piezocomposite bimorph. Restrictions in material properties lead to vehicle inefficiencies caused by the discontinuous geometry of deflected control surfaces in unmanned aircraft systems. This performance disadvantage in discrete control surfaces is caused in part by the sharp edges that are formed when the surface is pivoted. Flow continuity over the body of a vehicle is important in minimizing the effects of …

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An Experimental Investigation Of Heat Transfer For Arrays Of Impingement Jets Onto The Featured Surfaces With Cylindrical And Elliptical Raised Surfaces, Marc A. Medina Jan 2016

An Experimental Investigation Of Heat Transfer For Arrays Of Impingement Jets Onto The Featured Surfaces With Cylindrical And Elliptical Raised Surfaces, Marc A. Medina

Honors Undergraduate Theses

This study focuses on multi-jet impingement for gas turbine geometries in which the objective is to understand the influence of the roughness elements on a target surface to the heat transfer. Current work has proven that implementing roughness elements for multi-jet impingement target surfaces has increased heat transfer ranging anywhere from 10-30%. This study has chosen to investigate three different roughness elements, elliptical in cross-section, to compare to smooth surface geometries for multi-jet impingement. An experimental was taken for this study to extend the current knowledge of multi-jet impingement geometries and to further understand the heat transfer performance. A temperature …

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Conjugate Heat Transfer Analysis Of Combined Regenerative And Discrete Film Cooling In A Rocket Nozzle, Charlotte M. Pearce Jan 2016

Conjugate Heat Transfer Analysis Of Combined Regenerative And Discrete Film Cooling In A Rocket Nozzle, Charlotte M. Pearce

Honors Undergraduate Theses

Conjugate heat transfer analysis has been carried out on an 89kN thrust chamber in order to evaluate whether combined discrete film cooling and regenerative cooling in a rocket nozzle is feasible. Several cooling configurations were tested against a baseline design of regenerative cooling only. New designs include combined cooling channels with one row of discrete film cooling holes near the throat of the nozzle, and turbulated cooling channels combined with a row of discrete film cooling holes. Blowing ratio and channel mass flow rate were both varied for each design. The effectiveness of each configuration was measured via the maximum …

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Characterization Of Dispersion And Residual Stress In Nanoparticle Reinforced Hybrid Carbon Fiber Composites, Alex Selimov Jan 2016

Characterization Of Dispersion And Residual Stress In Nanoparticle Reinforced Hybrid Carbon Fiber Composites, Alex Selimov

Honors Undergraduate Theses

Hybrid carbon fiber reinforced composites are a new breed of materials that are currently being explored and characterized for next generation aerospace applications. Through the introduction of secondary reinforcements, such as alumina nanoparticles, hybrid properties including improved mechanical properties and stress sensing capabilities can be achieved. In order to maximize these properties, it is necessary to achieve a homogeneous dispersion of particulate filler. Utilizing the photoluminescent properties of alumina, it is possible to compare local levels of particle concentration through emission intensities as a way to determine the effectiveness of the tested manufacturing parameters in increasing material homogeneity. Parameters of …

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The Mechanical Response And Parametric Optimization Of Ankle-Foot Devices, Kevin Smith Jan 2016

The Mechanical Response And Parametric Optimization Of Ankle-Foot Devices, Kevin Smith

Electronic Theses and Dissertations

To improve the mobility of lower limb amputees, many modern prosthetic ankle-foot devices utilize a so called energy storing and return (ESAR) design. This allows for elastically stored energy to be returned to the gait cycle as forward propulsion. While ESAR type feet have been well accepted by the prosthetic community, the design and selection of a prosthetic device for a specific individual is often based on clinical feedback rather than engineering design. This is due to an incomplete understanding of the role of prosthetic design characteristics (e.g. stiffness, roll-over shape, etc.) have on the gait pattern of an individual. …

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Intrinsic Modulation Response Modeling And Analysis For Lithographic Vertical-Cavity Surface-Emitting Lasers, Mingxin Li Jan 2016

Intrinsic Modulation Response Modeling And Analysis For Lithographic Vertical-Cavity Surface-Emitting Lasers, Mingxin Li

Electronic Theses and Dissertations

Vertical-cavity surface-emitting lasers (VCSELs) have been greatly improved and successfully commercialized over the past few decades owing to their ability to provide both mode and current confinement that enables low energy consumption, high efficiency and high modulation speed. However, further improvement of oxide VCSELs is limited by the nature of the oxide aperture because of self-heating, internal strain and difficulties in precise size control. In this dissertation, VCSELs using lithographic approach are demonstrated to overcome the limitations of oxide VCSELs, in which an intra-cavity phase shifting mesa is applied to define the device size and provide optical mode and electrical …

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The Woz Recognizer: A Tool For Understanding User Perceptions Of Sketch-Based Interfaces, Jared Bott Jan 2016

The Woz Recognizer: A Tool For Understanding User Perceptions Of Sketch-Based Interfaces, Jared Bott

Electronic Theses and Dissertations

Sketch recognition has the potential to be an important input method for computers in the coming years; however, designing and building an accurate and sophisticated sketch recognition system is a time consuming and daunting task. Since sketch recognition is still at a level where mistakes are common, it is important to understand how users perceive and tolerate recognition errors and other user interface elements with these imperfect systems. A problem in performing this type of research is that we cannot easily control aspects of recognition in order to rigorously study the systems. We performed a study examining user perceptions of …

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Broad Bandwidth Optical Frequency Combs From Low Noise, High Repetition Rate Semiconductor Mode-Locked Lasers, Anthony Klee Jan 2016

Broad Bandwidth Optical Frequency Combs From Low Noise, High Repetition Rate Semiconductor Mode-Locked Lasers, Anthony Klee

Electronic Theses and Dissertations

Mode-locked lasers have numerous applications in the areas of communications, spectroscopy, and frequency metrology. Harmonically mode-locked semiconductor lasers with external ring cavities offer a unique combination of benefits in that they can produce high repetition rate pulse trains with low timing jitter, achieve narrow axial mode linewidths, have the potential for entire monolithic integration on-chip, feature high wall-plug efficiency due to direct electrical pumping, and can be engineered to operate in different wavelength bands of interest. However, lasers based on InP/InGaAsP quantum well devices which operate in the important telecom C-band have thus far been relatively limited in bandwidth as …

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Advanced Blue Phase Liquid Crystal Displays, Daming Xu Jan 2016

Advanced Blue Phase Liquid Crystal Displays, Daming Xu

Electronic Theses and Dissertations

Thin-film transistor (TFT) liquid crystal displays (LCDs) have become indispensable in our daily lives. Their widespread applications range from smartphones, laptops, TVs to navigational devices, data projectors and wearable displays. Over past decades, massive efforts have been invested in device development, material characterization and manufacturing technology. As a result, the performance of LCDs, such as viewing angle, contrast ratio, color gamut and resolution, have been improved significantly. Nonetheless, there are still urgent needs for fast response time and low power consumption. Fast response time helps reduce motion image blurs and enable color sequential displays. The latter is particularly attractive since …

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Dynamic Modeling Of Autorotation For Simultaneous Lift And Wind Energy Extraction, Sadaf Mackertich Jan 2016

Dynamic Modeling Of Autorotation For Simultaneous Lift And Wind Energy Extraction, Sadaf Mackertich

Electronic Theses and Dissertations

The goal of this thesis is to develop a multi-body dynamics model of autorotation with the objective of studying its application in energy harvesting. A rotor undergoing autorotation is termed an Autogyro. In the autorotation mode, the rotor is unpowered and its interaction with the wind causes an upward thrust force. The theory of an autorotating rotorcraft was originally studied for achieving safe flight at low speeds and later used for safe descent of helicopters under engine failure. The concept can potentially be used as a means to collect high-altitude wind energy. Autorotation is inherently a dynamic process and requires …

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A Holistic Framework For Effective Engineering Leadership Development Using 3d Virtual World Simulation, Hamed Almalki Jan 2016

A Holistic Framework For Effective Engineering Leadership Development Using 3d Virtual World Simulation, Hamed Almalki

Electronic Theses and Dissertations

Problems associated with the limited success of traditional engineering leadership development are the absence of embedded real-life industry case studies in leadership development and incorrect applications of leadership strategies in the various contexts. Though recommended programs for enhancing leadership development exist, they lack an examined framework, especially when it comes to leadership development of undergraduate engineering students. In this research effort, the impact of a framework using 3D virtual world simulation and the 4-D Leadership System to enhance the leadership abilities of undergraduate engineering students at the individual and team levels based on industrial leadership case studies was investigated. The …

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Multi-Purpose Device For Analyzing And Measuring Ultra-Short Pulses, Naman Anilkumar Mehta Jan 2016

Multi-Purpose Device For Analyzing And Measuring Ultra-Short Pulses, Naman Anilkumar Mehta

Electronic Theses and Dissertations

Intensity auto correlator is device to measure pulse widths of ultrashort pulses on the order of picoseconds and femtoseconds. I have built an in-house, compact, portable, industry standard intensity auto correlator for measuring ultrashort pulse-widths. My device is suitable for pulse-widths from 500 ps to 50 fs. The impetus for developing this instrument stemmed from our development of a multicore-fiber laser for high power laser applications, which also produces very short pulses that cannot be measured with an oscilloscope. As techniques for measuring short pulse-widths have been well studied, what made my journey exciting was the process of taking an …

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Web Tools: Keeping Learners On Pace, Mickey Kosloski Jan 2016

Web Tools: Keeping Learners On Pace, Mickey Kosloski

STEMPS Faculty Publications

One of the greatest challenges in teaching technology and engineering is pacing. Some students grasp new technological concepts quickly, while others need repetition and may struggle to keep pace. This poses an obstacle for the technology and engineering teacher, and is particularly true when teaching students to build a website. However, there are a plethora of online tools available that can assist learners in building a website. This article identifies some of the tools that may be used in the classroom and for classroom-oriented, teacher-hosted websites. While specific examples are provided, Web search terms are denoted at the end of …

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Spatial-Temporal Stochasticity Of Electric Vehicles In Integrated Traffic And Power System, Sadhana Shrestha Jan 2016

Spatial-Temporal Stochasticity Of Electric Vehicles In Integrated Traffic And Power System, Sadhana Shrestha

Electronic Theses and Dissertations

A penetration of a large number of electric vehicles for charging their batteries in the grid can have a negative impact to the grid. To prevent a negative effect to the grid, the behavior of electric vehicles must be accurately modeled and their charging schedules must be coordinated. Therefore, it is necessary to determine where and how much charge is available in electric vehicles in the distribution system. In this thesis, a state transition algorithm is designed to determine a stochastic model of electric vehicles to simulate electric vehicle movement in an integrated traffic and power network. Dijkstra’s algorithm is …

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