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Full-Text Articles in Engineering

Unsteady Effects Of A Pulsed Blowing System On An Endwall Vortex, Molly Hope Donovan Jan 2019

Unsteady Effects Of A Pulsed Blowing System On An Endwall Vortex, Molly Hope Donovan

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The low-pressure turbine is an important component of a gas turbine engine, powering the low-pressure spool which provides the bulk of the thrust in medium- and high-bypass engines. It is also a significant fraction of the engine weight and complexity as it can comprise up to a third of the total engine weight. One way to drastically reduce the weight of the low-pressure turbine is to utilize high lift blades. To advance high-lift technology, the Air Force Research Laboratory (AFRL) designed the L2F blade profile, which was implemented in the linear cascade at AFRL/RQT’s low speed wind tunnel facility. The …


Multi-Sensor Approach To Determine The Effect Of Geometry On Microstructure In Additive Manufacturing, Joseph R. Walker Jan 2019

Multi-Sensor Approach To Determine The Effect Of Geometry On Microstructure In Additive Manufacturing, Joseph R. Walker

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Laser powder bed fusion (LPBF) is an additive manufacturing technique used for making complex parts through a layer-by-layer process with fine feature resolution. However, the layer-by-layer process, with complex scanning patterns within each layer, introduces variability in thermal behavior leading to inconsistent microstructure and defects. The in- situ process monitoring approach in this work uses sensors including a high-speed visible camera, thermal camera, and spectrometer to evaluate each location in the LPBF process. Each sensor focuses on a different process phenomenon such as the melt pool or thermal behavior. An experimental study, using metallographic analysis and collection of sensor data, …


Software Implementations And Applications Of Elliptic Curve Cryptography, Kirill Kultinov Jan 2019

Software Implementations And Applications Of Elliptic Curve Cryptography, Kirill Kultinov

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Elliptic Curve Cryptography (ECC) is a public-key cryptography system. Elliptic Curve Cryptography (ECC) can achieve the same level of security as the public-key cryptography system, RSA, with a much smaller key size. It is a promising public key cryptography system with regard to time efficiency and resource utilization. This thesis focuses on the software implementations of ECC over finite field GF(p) with two distinct implementations of the Big Integer classes using character arrays, and bit sets in C++ programming language. Our implementation works on the ECC curves of the form y^2 = x^3 + ax + b (mod p). The …


Biomarker-Performance Associations During Nutritional And Exercise Intervention In Air Force Personnel, Jennifer Jurcsisn Jan 2019

Biomarker-Performance Associations During Nutritional And Exercise Intervention In Air Force Personnel, Jennifer Jurcsisn

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This study evaluated the combined effects of an exercise intervention and nutritional supplement on biomarkers of stress and resilience, and the relationships of those markers with physical and cognitive performance. 130 healthy Active-Duty Air Force (AF) personnel were recruited to participate in a double-blind, placebo controlled 12-week exercise and nutritional intervention. Serum was collected at basal and high stress conditions pre- and post-intervention to track the following biomarkers: cortisol, dehydroepiandrosterone-sulfate (DHEA-S), norepinephrine (NE), neuropeptide Y (NPY), and serotonin. The exercise intervention significantly attenuated the cortisol response and peak stress cortisol levels. The nutritional intervention decreased peak stress NE. The selected …


Rules With Right Hand Existential Or Disjunction With Rowltab, Sri Jitendra Satpathy Jan 2019

Rules With Right Hand Existential Or Disjunction With Rowltab, Sri Jitendra Satpathy

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One hotly debated research topic is, “What is the best approach for modeling ontologies?”. In the earlier stages of modeling ontologies, researchers have favored the usage of description logic to capture knowledge. One such choice is the Web Ontology Language (OWL) that is based on description logic. Many tools were designed around this principle and are still widely being used to model and explore ontologies. However, not all users find description logic to be intuitive, at least not without an extensive background in formal logics. Due to this, researchers have tried to explore other ways that will enable such users …


Computational Simulation Of A Femoral Nail Fracture, Stephen Charles Whatley Jan 2019

Computational Simulation Of A Femoral Nail Fracture, Stephen Charles Whatley

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Every year in the United States roughly 300,000 people over the age of 65 suffer from a hip fracture. Ninety five percent of which are the result from a fall. The resulting hip fracture can be classified into several categories of fracture. Depending on the damage the patient could be implanted with a femoral nail device to assist in their recovery. These devices can, however, have complications during recovery. In some cases, these nails can have a failure rate as high as 10%. When failure occurs, extensive investigations are needed to determine the causes of failure. These investigations involve physical …


Scalable Clustering For Immune Repertoire Sequence Analysis, Prem Bhusal Jan 2019

Scalable Clustering For Immune Repertoire Sequence Analysis, Prem Bhusal

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The development of the next-generation sequencing technology has enabled systems immunology researchers to conduct detailed immune repertoire analysis at the molecule level. Large sequence datasets (e.g., millions of sequences) are being collected to comprehensively understand how the immune system of a patient evolves over different stages of disease development. A recent study has shown that the hierarchical clustering (HC) algorithm gives the best results for B-cell clones analysis - an important type of immune repertoire sequencing (IR-Seq) analysis. However, due to the inherent complexity, the classical hierarchical clustering algorithm does not scale well to large sequence datasets. Surprisingly, no algorithms …


A Model To Optimize Major Trauma Network Considering Patient Safety, Monit D. Vaishnav Jan 2019

A Model To Optimize Major Trauma Network Considering Patient Safety, Monit D. Vaishnav

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Trauma is any physical injury that has the potential to cause prolonged disability and death if the appropriate level of care is not administered in a timely fashion. Existing approaches in the literature and by the American College of Surgeons (ACS) to optimize the network of trauma centers are limiting. To address this challenge, we introduce the Trauma Network Design Problem, a bi-objective mathematical model that aims at determining the optimal trauma network by minimizing the weighted sum of mistriages. We use the trauma network data from 2012 for the state of Ohio to illustrate the use of our approach …


Development Of A Computer Program For Transient Heat Transfer Coefficient Studies, Sri Prithvi Samrat Samayamantula Jan 2019

Development Of A Computer Program For Transient Heat Transfer Coefficient Studies, Sri Prithvi Samrat Samayamantula

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At the present time, the magnitude of transient convective heat transfer is approximated using heat transfer coefficient correlations developed for steady state conditions. This is done by necessity, as transient heat transfer correlations are not readily available. There is a rare transient heat transfer correlation found in the literature, but the number of correlations available can be counted on one hand. In addition, the literature does provide some plots of Nusselt numbers for specific cases of transient convective heat transfer, but these are limited to the specific case for which they were developed. The work presented in this thesis is …


Characterization Of In-Vivo Damage In Implantable Cardiac Devices And The Lead Residual Properties, Anmar Mahdi Salih Jan 2019

Characterization Of In-Vivo Damage In Implantable Cardiac Devices And The Lead Residual Properties, Anmar Mahdi Salih

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Approximately, 92.1 million patients in the US suffer from cardiovascular diseases with an estimated healthcare cost of over $300 billion; out of which at least one million patients have Cardiac Implantable Electronics Devices (CIED). CIED represented by pacemakers, Implantable Cardioversion Defibrillator (ICD), and Cardiac Resynchronization Therapy (CRT) are exposed to in-vivo damage. These damages are complex and composed on multiple levels and present challenges while assessing their combined extent. Since 2004, more than one hundred recalls were reported for cardiac devices. ICD devices had the majority with 40.8% recalls, pacemaker recall percentage was 14.5%, CRT recall percentage was12.7%, leads recalls …


Growth Of Two-Dimensional Molybdenum Disulfide Via Chemical Vapor Deposition, Zachary Durnell Ganger Jan 2019

Growth Of Two-Dimensional Molybdenum Disulfide Via Chemical Vapor Deposition, Zachary Durnell Ganger

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Graphene has successfully been a 2D material applied in various fields, but it is not the most appropriate candidate for many electronic devices unless its bandgap structure is tuned through functionalization. Among all other 2D material families, transition metal dichalcogenides (TMDs), represented by molybdenum disulfide (MoS2), are promising and emerging in power electronics due to their large direct bandgap and other electronic properties. 2D MoS2 has been fabricated through different approaches such as mechanical exfoliation, chemical etching, and chemical vapor deposition (CVD). The current major challenge in fabricating 2D MoS2 films is to produce a high-quality large-area monolayer film at …


Two Player Zero Sum Multi-Stage Game Analysis Using Coevolutionary Algorithm, Sumedh Sopan Nagrale Jan 2019

Two Player Zero Sum Multi-Stage Game Analysis Using Coevolutionary Algorithm, Sumedh Sopan Nagrale

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A New Two player zero sum multistage simultaneous Game has been developed from a real-life situation of dispute between two individual. Research identifies a multistage game as a multi-objective optimization problem and solves it using Coevolutionary algorithm which converges to a solution from pareto optimal solution. A comparison is done between individual stage behaviour and multistage behaviour. Further, simulations over a range for Crossover rate, Mutation rate and Number of interaction is done to narrow down the range for a range with optimal computation speed. A relationship has been observed which identifies a relationship between population size, number of interactions, …


Processing And Properties Of Multifunctional Two-Dimensional Nanocomposite Based On Single Wall Carbon Nanotubes, Ali M. Al Mafarage Jan 2019

Processing And Properties Of Multifunctional Two-Dimensional Nanocomposite Based On Single Wall Carbon Nanotubes, Ali M. Al Mafarage

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Truly single layer (monolayer) films of unmodified zigzag single-walled carbon nanotubes by using the Langmuir-Blodgett (LB) technique have been processed successfully. Measurements of their mechanical and optoelectric properties were achieved. Different theoretical equations were used based on the results obtained from the experimental part to study the properties and structures of the produced material and their composite. The produced films were highly oriented as determined by polarized Raman spectroscopy and as shown by scanning tunneling microscopy (STM). The films have a significant amount of flexibility which makes their behavior similar to rubbery materials. They can also be deposited on different …


Power/Thermal Interaction Within An Adaptive Turbine Engine, Andrew K. Desomma Jan 2019

Power/Thermal Interaction Within An Adaptive Turbine Engine, Andrew K. Desomma

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Usually power take off (PTO) with a two-spool turbofan engine has been accomplished via the high pressure (HP) shaft and bleed air from the high-pressure compressor (HPC). The PTO is used to run various aircraft components such as generators and hydraulic pumps, which also produce waste heat. To better understand the coupled transient nature of balancing engine thrust, power take off and thermal management, a transient variable cycle three stream turbofan engine model has been developed to investigate the integrated behavior. The model incorporates many dynamic features including a third-stream heat exchanger as a heat sink for thermal management and …


System Identification And Model-Based Control Of Quadcopter Uavs, Andrew P. Szabo Jan 2019

System Identification And Model-Based Control Of Quadcopter Uavs, Andrew P. Szabo

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As control systems become more sophisticated, more accurate system models are needed for control law design and simulation. In this research, a nonlinear dynamic model of a quadcopter UAV is presented and model parameters are estimated off-line using in-flight experimental data. In addition, a model-based classical control law for the quadcopter UAV is designed, simulated, and then deployed in UAV flight tests. The intent of this research is to identify a model which may be simple enough to easily use for control law design, and accurate enough for simulation. In addition, a model-based classical control law is designed to for …


Abusive And Hate Speech Tweets Detection With Text Generation, Abhishek Nalamothu Jan 2019

Abusive And Hate Speech Tweets Detection With Text Generation, Abhishek Nalamothu

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According to a Pew Research study, 41% of Americans have personally experienced online harassment and two-thirds of Americans have witnessed harassment in 2017. Hence, online harassment detection is vital for securing and sustaining the popularity and viability of online social networks. Machine learning techniques play a crucial role in automatic harassment detection. One of the challenges of using supervised approaches is training data imbalance. Existing text generation techniques can help augment the training data, but they are still inadequate and ineffective. This research explores the role of domain-specific knowledge to complement the limited training data available for training a text …


Strategic Decision Facilitation: An Exploration Of Alternative Anchoring And Scale Distortion Optimization In Multi-Attribute Group Decision Making, Joseph Patrick Kristbaum Jan 2019

Strategic Decision Facilitation: An Exploration Of Alternative Anchoring And Scale Distortion Optimization In Multi-Attribute Group Decision Making, Joseph Patrick Kristbaum

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Choosing between alternatives, regardless of the decision context in an organizational group setting is a difficult task. The integrity of the decision is under constant scrutiny and rarely are we ever able to characterize the magnitude of that with which we are consciously or subconsciously concerned: personal bias. This leads to long, drawn out timelines and loosely trusted decisions. This dissertation research focuses on using a traditionally, negatively viewed anchoring bias strategically in a series of experiments with a hypothesis that it can be used to positively reduce personal biases such as preference bias and judgement rooted in ambiguous or …


Automated Vehicle Electronic Control Unit (Ecu) Sensor Location Using Feature-Vector Based Comparisons, Gregory S. Buthker Jan 2019

Automated Vehicle Electronic Control Unit (Ecu) Sensor Location Using Feature-Vector Based Comparisons, Gregory S. Buthker

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In the growing world of cybersecurity, being able to map and analyze how software and hardware interact is key to understanding and protecting critical embedded systems like the Engine Control Unit (ECU). The aim of our research is to use our understanding of the ECU's control flow attained through manual analysis to automatically map and identify sensor functions found within the ECU. We seek to do this by generating unique sets of feature vectors for every function within the binary file of a car ECU, and then using those feature sets to locate functions within each binary similar to their …


Recognition Of Incomplete Objects Based On Synthesis Of Views Using A Geometric Based Local-Global Graphs, Michael Christopher Robbeloth Jan 2019

Recognition Of Incomplete Objects Based On Synthesis Of Views Using A Geometric Based Local-Global Graphs, Michael Christopher Robbeloth

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The recognition of single objects is an old research field with many techniques and robust results. The probabilistic recognition of incomplete objects, however, remains an active field with challenging issues associated to shadows, illumination and other visual characteristics. With object incompleteness, we mean missing parts of a known object and not low-resolution images of that object. The employment of various single machine-learning methodologies for accurate classification of the incomplete objects did not provide a robust answer to the challenging problem. In this dissertation, we present a suite of high-level, model-based computer vision techniques encompassing both geometric and machine learning approaches …


Knowledge Graph Reasoning Over Unseen Rdf Data, Bhargavacharan Reddy Kaithi Jan 2019

Knowledge Graph Reasoning Over Unseen Rdf Data, Bhargavacharan Reddy Kaithi

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In recent years, the research in deep learning and knowledge engineering has made a wide impact on the data and knowledge representations. The research in knowledge engineering has frequently focused on modeling the high level human cognitive abilities, such as reasoning, making inferences, and validation. Semantic Web Technologies and Deep Learning have an interest in creating intelligent artifacts. Deep learning is a set of machine learning algorithms that attempt to model data representations through many layers of non-linear transformations. Deep learning is in- creasingly employed to analyze various knowledge representations mentioned in Semantic Web and provides better results for Semantic …


Knowledge-Enabled Entity Extraction, Hussein S. Al-Olimat Jan 2019

Knowledge-Enabled Entity Extraction, Hussein S. Al-Olimat

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Information Extraction (IE) techniques are developed to extract entities, relationships, and other detailed information from unstructured text. The majority of the methods in the literature focus on designing supervised machine learning techniques, which are not very practical due to the high cost of obtaining annotations and the difficulty in creating high quality (in terms of reliability and coverage) gold standard. Therefore, semi-supervised and distantly-supervised techniques are getting more traction lately to overcome some of the challenges, such as bootstrapping the learning quickly. This dissertation focuses on information extraction, and in particular entities, i.e., Named Entity Recognition (NER), from multiple domains, …


Design Of An Ultra-Wideband Microstrip Antenna Array With Low Size, Weight And Power, Paul Staffan Jan 2019

Design Of An Ultra-Wideband Microstrip Antenna Array With Low Size, Weight And Power, Paul Staffan

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This study focuses on the use of microstrip antenna technology for designing an ultra-wideband antenna to meet low size, weight and power requirements. Based on the recent literature for such antennas, a quasi-log periodic microstrip antenna array is designed to operate from 8 to 40 GHz (radar bands X, Ku, K and Ka). The array consists of 33 co-linear, inset-fed, square patches on a Roger’s Duroid substrate, and is modeled using the Advanced Design System software from Keysight. The simulated results show the antenna has pass-band gains greater than 5 dB, a half-power beamwidth of 30 degrees, and linear polarization …


Monitoring Cerebral Functional Response Using Scmos-Based High Density Near Infrared Spectroscopic Imaging, Dharminder Singh Langri Jan 2019

Monitoring Cerebral Functional Response Using Scmos-Based High Density Near Infrared Spectroscopic Imaging, Dharminder Singh Langri

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Neurovascular coupling is an important concept that indicates the direct link between neuronal electrical firing with the vascular hemodynamic changes. Functional Near Infrared Spectroscopy (fNIRS) can measure changes in cerebral vascular parameters of oxy-hemoglobin and deoxyhemoglobin concentrations and thus can provide neuronal activity through neurovascular coupling. Currently many commercial fNIRS devices are available, but they are limited by the number of channels (usually having only 8 detectors), which can limit the sensitivity, contrast, and resolution of imaging. High-density imaging can improve sensitivity, contrast, and resolution by providing many measurements and averaging the signals originating from the target cerebral focus area …