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Articles 691 - 720 of 1369
Full-Text Articles in Engineering
Software Defined Secure Ad Hoc Wireless Networks, Maha Alqallaf
Software Defined Secure Ad Hoc Wireless Networks, Maha Alqallaf
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Software defined networking (SDN), a new networking paradigm that separates the network data plane from the control plane, has been considered as a flexible, layered, modular, and efficient approach to managing and controlling networks ranging from wired, infrastructure-based wireless (e.g., cellular wireless networks, WiFi, wireless mesh net- works), to infrastructure-less wireless networks (e.g. mobile ad-hoc networks, vehicular ad-hoc networks) as well as to offering new types of services and to evolving the Internet architecture. Most work has focused on the SDN application in traditional and wired and/or infrastructure based networks. Wireless networks have become increasingly more heterogeneous. Secure and collab- …
Multi-Carrier Radar For Target Detection And Communications, John David Ellinger
Multi-Carrier Radar For Target Detection And Communications, John David Ellinger
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This dissertation considers the optimization of radar performance within the structure imposed by a coded Orthogonal Frequency Division Multiplexing (OFDM) format required to achieve an acceptable communication link. The dual goal of achieving both satisfactory radar and communication performance raises challenges that can be substantively addressed by combining phase coding and modulation techniques to provide the temporal and spectral structure necessary to implement simultaneous radar and communication operations. In particular, the specific techniques, as introduced within this dissertation, of using the Multi-Frequency Complementary Phase Coded (MCPC) sequences, as prescribed by Levanon and Mozeson, for simultaneous radar and wireless communication operations …
The Effect Of Laser Power And Scan Speed On Melt Pool Characteristics Of Pure Titanium And Ti-6al-4v Alloy For Selective Laser Melting, Chandrakanth Kusuma
The Effect Of Laser Power And Scan Speed On Melt Pool Characteristics Of Pure Titanium And Ti-6al-4v Alloy For Selective Laser Melting, Chandrakanth Kusuma
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Selective Laser Melting (SLM) is an additive manufacturing (AM) technique that creates complex parts by selectively melting metal powder layer-by-layer. In SLM, the process parameters decide the quality of the fabricated component. In this study, single beads of commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy are melted on a substrate of the same material as powder using an in-house built SLM machine. Multiple combinations of laser power and scan speed are used for single bead fabrication while the laser beam diameter and powder layer thickness are kept constant. This experimental study investigates the influence of laser power, scan speed and …
Knowledge-Empowered Probabilistic Graphical Models For Physical-Cyber-Social Systems, Pramod Anantharam
Knowledge-Empowered Probabilistic Graphical Models For Physical-Cyber-Social Systems, Pramod Anantharam
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There is a rapid intertwining of sensors and mobile devices into the fabric of our lives. This has resulted in unprecedented growth in the number of observations from the physical and social worlds reported in the cyber world. Sensing and computational components embedded in the physical world constitute a Cyber-Physical System (CPS). Current science of CPS is yet to effectively integrate citizen observations in CPS analysis. We demonstrate the role of citizen observations in CPS and propose a novel approach to perform a holistic analysis of machine and citizen sensor observations. Specifically, we demonstrate the complementary, corroborative, and timely aspects …
Fault Diagnosis And Fault-Tolerant Control Of Quadrotor Uavs, Remus C. Avram
Fault Diagnosis And Fault-Tolerant Control Of Quadrotor Uavs, Remus C. Avram
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Quadrotors represent a special class of Unmanned Aerial Vehicles (UAVs) and have attracted significant attention in recent years due to their potential in various military and civilian applications. However, due to their intrinsic fabrication process and component damage, quadrotors are prone to various type of faults. This dissertation presents the design, analysis, and experimental implementation of fault diagnosis, fault-tolerant control, and controller verification methods to achieve safety assurance and trusted autonomy of quadrotor UAVs. First, the issue of sensor faults is investigated under two different scenarios: (1) the case when all Euler angles are available for measurement; (2) the case …
Design And Evaluation Of A Fiber Optic Shape Tracker For Use As A Navigational Aid In Endovascular Guidewires And Catheters, Benjamin Stewart Rinehart
Design And Evaluation Of A Fiber Optic Shape Tracker For Use As A Navigational Aid In Endovascular Guidewires And Catheters, Benjamin Stewart Rinehart
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Endovascular intervention is the current gold-standard for screening and treating aortic aneurysms and complications caused by peripheral vascular disease (PAD). A typical endovascular procedure begins with inserting an endovascular guidewire into the femoral artery via incision. A catheter is then threaded over the guidewire and both tools are then navigated to the treatment site. The navigation is guided solely by fluoroscopy (x-ray) imagery that is performed throughout the duration of the procedure. Not only does this method provide limited 2-D guidance, but also exposes the patient and medical staff to high levels of radiation. This thesis research focuses on the …
Fpga Realization Of Low Register Systolic All One-Polynomial Multipliers Over Gf (2M) And Their Applications In Trinomial Multipliers, Pingxiuqi Chen
Fpga Realization Of Low Register Systolic All One-Polynomial Multipliers Over Gf (2M) And Their Applications In Trinomial Multipliers, Pingxiuqi Chen
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All-one-polynomial (AOP)-based systolic multipliers over GF (2m) are usually not con-sidered for practical implementation of cryptosystems such as elliptic curve cryptography (ECC) due to security reasons. Besides that, systolic AOP multipliers usually suer from the problem of high register-complexity, especially in field-programmable gate array (FPGA) platforms where the register resources are not that abundant. In this thesis, however, we have shown that the AOP-based systolic multipliers can easily achieve low register-complexity implementations and the proposed architectures can be employed as computation cores to derive ecient implementations of systolic Montgomery multipli-ers based on trinomials, which are recommended by the National Institute …
A Theoretical Framework For Evaluating Mental Workload Resources In Human Systems Design For Manufacturing Operations, Sharon Claxton Bommer
A Theoretical Framework For Evaluating Mental Workload Resources In Human Systems Design For Manufacturing Operations, Sharon Claxton Bommer
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Manufacturing is a human-driven process that applies energy and manpower to produce consumer goods. In repetitive task processes like manufacturing systems, optimal performance is extremely important for the production employee and the company. In the general fast pace of manufacturing operations, there is the potential for operator errors, which correlates to possible safety issues and loss of revenue. This research explores the influence of cognitive resources on operator performance in manufacturing operations using the Multiple Resource Theory (MRT) and mental workload measures. Computer simulation models and mathematical modeling with Improved Performance Research Integration Tool (IMPRINT) were used to assess mental …
Growth And Characterization Of Molybdenum Disulfide Thin Films, Carl Morris Gross Iii
Growth And Characterization Of Molybdenum Disulfide Thin Films, Carl Morris Gross Iii
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Two-dimensional materials, or materials that are only one atomic layer thick, have seen much research in recent years because of their interesting electrical properties. The first of these materials, graphene, was found to have incredible electrical properties but lacked a bandgap in intrinsic films. Without a bandgap, graphene cannot create transistors that can be shut off. Molybdenum disulfide, however, is a two-dimensional semiconductor with a large bandgap. The main issue of molybdenum disulfide is that synthesized films are a much lower quality than their exfoliated counterparts. For molybdenum disulfide to be able to be used practically, a method of synthesis …
Performance Prediction Of Constrained Waveform Design For Adaptive Radar, Aaron M. Jones
Performance Prediction Of Constrained Waveform Design For Adaptive Radar, Aaron M. Jones
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Today's radars face an ever increasingly complex operational environment, intensified by the numerous types of mission/modes, number and type of targets, non-homogenous clutter and active interferers in the scene. Thus, the ability to adapt ones transmit waveform, to optimally suit the needs for a particular radar tasking and environment, becomes mandatory. This requirement brings with it a host of challenges to implement including the basic decision of what to transmit. In this dissertation, we discuss six original contributions, including the development of performance prediction models for constrained radar waveforms, that aid in the decision making process of an adaptive radar …
Refining A Post-Stroke Pharmacological And Physical Treatment To Reduce Infarct Volume Or Improve Functional Recovery, Using Gene Expression Changes In The Peri-Infarct Region To Examine Potential Mechanisms In Male And Female Rats, Moner A. Ragas
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Stroke, a life-threatening medical condition, is the fifth-leading cause of death in the United States with an estimated annual cost of treatments above $70 billion. A combination of innovative approaches was used in our lab to optimize the pre-clinical stroke research design by choosing the most appropriate animal model and methodologies to increase the translational capability of the stroke research. The first study, modeled after ongoing clinical trials using fluoxetine, refined the appropriate timing of fluoxetine and ascorbic acid delivery if a rat was on simvastatin for 7 days pre-stroke and throughout the remainder of the study. Administration of fluoxetine …
Co-Transplantation Of Endothelial Progenitor Cells And Neural Progenitor Cells For Treating Ischemic Stroke In A Mouse Model, Jinju Wang
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Ischemic stroke (IS) is a major cause of death and disability with limited and less effective therapeutics. Transplantation of stem cells, such as neuronal progenitor cells (NPCs) and endothelial progenitor cells (EPCs), is promising for treating IS. It is well known that neurogenesis and angiogenesis are critical for cerebral repair following ischemic injury. However, whether co-transplantation of EPCs and NPCs has synergistic effects remains unclarified. In addition, the PI3K/Akt pathway participates in modulating a widely range of cellular functions such as anti-apoptotic and anti-oxidant. The signal pathways responsible for the effects of grafted NPCs and EPCs are also waiting for …
Modular Multi-Signal Tracking Pulse Descriptor Word (Pdw) Generator With Field Programmable Gate Array (Fpga) Implementation, Justin Darrell Pelan
Modular Multi-Signal Tracking Pulse Descriptor Word (Pdw) Generator With Field Programmable Gate Array (Fpga) Implementation, Justin Darrell Pelan
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As signal spectra become dense, the task of tracking and identifying radars becomes increasingly cumbersome. The variety of radars in modern theaters of war compound the task due to simultaneous operation. Real-time processing of large data sets prove difficult for sequential systems, and the parallelism of Field Programmable Gate Arrays (FPGAs) becomes an attractive option. To mitigate the increasing complexity of this task, this design proposes an FPGA architecture to produce pulse descriptor words (PDW) for up to eight independent radio frequency signals that can be used in near-real-time processing. Focusing on digital hardware techniques and modular design allow for …
Knowledge-Driven Implicit Information Extraction, Pathirage Dinindu Perera
Knowledge-Driven Implicit Information Extraction, Pathirage Dinindu Perera
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Natural language is a powerful tool developed by humans over hundreds of thousands of years. The extensive usage, flexibility of the language, creativity of the human beings, and social, cultural, and economic changes that have taken place in daily life have added new constructs, styles, and features to the language. One such feature of the language is its ability to express ideas, opinions, and facts in an implicit manner. This is a feature that is used extensively in day to day communications in situations such as: 1) expressing sarcasm, 2) when trying to recall forgotten things, 3) when required to …
Probabilistic Svm For Open Set Automatic Target Recognition On High Range Resolution Radar Data, Jason Daniel Roos
Probabilistic Svm For Open Set Automatic Target Recognition On High Range Resolution Radar Data, Jason Daniel Roos
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The application of Automatic Target Recognition (ATR) on High Range Resolution (HRR) radar data in a scenario that contains unknown targets is of great interest for military and civilian applications. HRR radar data provides greater resolution of a target as well as the ability to perform ATR on a moving target, which gives it an advantage over other imaging systems. With the added resolution of HRR comes the disadvantage that a change in the aspect angle or orientation results in greater changes in the collected data, making classical ATR more difficult. Closed set ATR on HRR radar data is defined …
The Effects Of Micro-Dimple Texture On The Friction And Thermal Behavior Of A Point Contact, Utsav Kamleshbhai Parmar
The Effects Of Micro-Dimple Texture On The Friction And Thermal Behavior Of A Point Contact, Utsav Kamleshbhai Parmar
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This study investigates the effects of the micro-dimple texture on the friction and surface temperature performances of a ball-on-disk contact, operating under the speed and load ranges that cover typical gearing applications. Circular shaped micro-dimple arrays with different dimple center distances and dimple depths are implemented on the ball surface to quantify the impacts of these two parameters on the friction coefficient and the maximum ball surface temperature. In addition, the contacts of three surface texture combinations, namely micro-dimpled and polished ball surface versus polished disk surface, polished ball surface versus polished disk surface and ground ball surface versus ground …
Nonreciprocal Magnetostatic Surface Wave In Thin Ferromagnetic Film, Kumar Vishal
Nonreciprocal Magnetostatic Surface Wave In Thin Ferromagnetic Film, Kumar Vishal
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Interest in the nonreciprocal property of waves inside the magnetic material starts with its current advancement in the field of passive devices. In current technology passive devices without magnetic cores are realized on a silicon chip, usually these devices are lossy and bigger in size. Passive devices constructed with magnetic core material such as isolators, circulators, phase shifters, and gyrators; gives us the chance to minimize such losses. Nonreciprocity in magnetic material is due to the anisotropic property of permeability, it is complex in nature and represent in 3×3 matrix form. We can control the wave flow inside the nonreciprocal …
Retail Facility Design Considering Product Exposure, Corinne H. Mowrey
Retail Facility Design Considering Product Exposure, Corinne H. Mowrey
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Retail store's layout affects a shopper's visual experience and correspondingly the time spent in the store, navigation through the aisles, and allocation of attention and money across departments and categories. We contend that alternate rack layouts allow for more of a rack's facing to appear in the shopper's visual field. In this work we focus on the following two questions: (i) what impact does a given rack layout have on how much of a rack display is exposed to a shopper? (ii) what rack layouts maximize exposure to a shopper? To address the first question, we introduce a set of …
A Fractal-Based Mathematical Model For Cancellous Bone Growth Considering The Hierarchical Nature Of Bone, Stephanie Marie Suhr
A Fractal-Based Mathematical Model For Cancellous Bone Growth Considering The Hierarchical Nature Of Bone, Stephanie Marie Suhr
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The hierarchical structure of bone alone is not comprehensive enough to provide morphological explanation of how the size and arrangement of the trabeculae within cancellous bone affect load distribution, particularly concerning deterioration of bone in elderly patients. The collagen network and hydroxyapatite play a large role in defining the shape of trabeculae in cancellous bone despite that the arrangement and size is seemingly random. The growth of plates and rods in cancellous bone is mainly due to loading and stress lines within the bone, but mathematical predictive models can be developed using fractal analysis to show how bone may grow …
Elucidating The Role Of Microstructure, Texture, And Microtexture On The Dwell Fatigue Response Of Ti-6al-4v, Alec Mitchell Blankenship
Elucidating The Role Of Microstructure, Texture, And Microtexture On The Dwell Fatigue Response Of Ti-6al-4v, Alec Mitchell Blankenship
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Ambient temperature dwell sensitivity is known to be deleterious to the fatigue response of near-alpha titanium alloys. Dwell fatigue refers to the presence of a sustained hold at peak stress as opposed to the continuous variation of normal cyclic fatigue loading. This reduction in failure life-times from dwell loading is attributed to early crack nucleation and faster crack propagation. The degradation is the result of plastic anisotropy on the microstructural scale along with tendency of titanium alloys to creep at low temperatures at stresses well below the 0.2% offset yield strength. Despite being the most widely used titanium alloy, Ti-6Al-4V …
Implementation Of Logic Fault Tolerance On A Dynamically Reconfigurable Fpga, Kiran Jayarama
Implementation Of Logic Fault Tolerance On A Dynamically Reconfigurable Fpga, Kiran Jayarama
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Relative to integrated circuit (IC) systems, on-chip fault detection entails determi- nation of whether or not a fault exists. The cause of the fault could be some faulty logic resource or some faulty interconnect (wiring) resource, but typically, fault detection only determines if a fault exists, not what exactly is faulty. Beyond pure fault detection some work has been done relative to on-chip fault analysis to fur- ther determine not only if a fault exists, but exactly what is faulty. Even less work has been done to actually tolerate faulty resources once they have been found. For this work, we …
Early Assessment Of Burn Severity In Human Tissue With Multi-Wavelength Spatial Frequency Domain Imaging, Chien Sing Poon
Early Assessment Of Burn Severity In Human Tissue With Multi-Wavelength Spatial Frequency Domain Imaging, Chien Sing Poon
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Burn injuries such as thermal burns, which are caused by contact with flames, hot liquids, hot surfaces, and other sources of high heat as well as chemical burns and electrical burns, affects at least 500,000 people in the United States, to which 45,000 of them require medical treatment and 3,500 of them result in death. It has also been reported that in the United States alone, fire results in a death approximately every three hours and an injury every 33 minutes. Early knowledge about burn severity can lead to improved outcome for patients. In this study, the changes in optical …
On The Experimental Evaluation Of Loss Production And Reduction In A Highly Loaded Low Pressure Turbine Cascade, Philip Steven Bear
On The Experimental Evaluation Of Loss Production And Reduction In A Highly Loaded Low Pressure Turbine Cascade, Philip Steven Bear
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Improvements in turbine design methods have resulted in the development of blade profiles with both high lift and good Reynolds lapse characteristics. An increase in aerodynamic loading of blades in the low pressure turbine section of aircraft gas turbine engines has the potential to reduce engine weight or increase power extraction. Increased blade loading means larger pressure gradients and increased secondary losses near the endwall. Prior work has emphasized the importance of reducing these losses if highly loaded blades are to be utilized. The present study analyzes the secondary flow field of the front-loaded low-pressure turbine blade designated L2F with …
Optical Redox Imaging Of Metabolic Activity, Syed Anwar Hyder Zaidi
Optical Redox Imaging Of Metabolic Activity, Syed Anwar Hyder Zaidi
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Fluorescence imaging can be used to determine tissue metabolism, which is an indication of the cellular functionality. Metabolic contrast is useful for the early detection of several medical conditions such as cancer, diabetes, lung diseases etc. This study aims to use fluorescence imaging to quantify NADH and FAD, which are cellular metabolic indicators. A parameter known as Redox ratio, can be used to study metabolic state of several tissue types and disease states. To quantify the Redox ratio, three fluorescence imaging systems were optimized to measure the fluorescence signal from NADH and FAD. The first system was a camera based …
Distributed Rule-Based Ontology Reasoning, Raghava Mutharaju
Distributed Rule-Based Ontology Reasoning, Raghava Mutharaju
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The vision of the Semantic Web is to provide structure and meaning to the data on the Web. Knowledge representation and reasoning play a crucial role in accomplishing this vision. OWL (Web Ontology Language), a W3C standard, is used for representing knowledge. Reasoning over the ontologies is used to derive logical consequences. A fixed set of rules are run on an ontology iteratively until no new logical consequences can be derived. All existing reasoners run on a single machine, possibly using multiple cores. Ontologies (sometimes loosely referred to as knowledge bases) that are automatically constructed can be very large. Single …
Customizable 3-D Virtual Gi Tract Systems For Locating, Mapping, And Navigation Inside Human Gastrointestinal Tract, Megha Dattatrey Dalvi
Customizable 3-D Virtual Gi Tract Systems For Locating, Mapping, And Navigation Inside Human Gastrointestinal Tract, Megha Dattatrey Dalvi
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One of the critical challenges of wireless capsule endoscopy examination is to find the exact position of the capsule in the Gastrointestinal Tract (GI) tract so as to correctly and accurately spot the position of the intestinal diseases. Creating a 3D virtual GI tract system could significantly improve the capsule endoscopy operations. The virtual human model, such as the BioDigital Human, has been credited as Google Earth for the human body, which provides us medically accurate virtual body and organ structures. However, it only assembles a “Standard” human body. The problem is: there is only one earth, but billions of …
Augment Hololens’ Body Recognition And Tracking Capabilities Using Kinect, Krishna Chaithanya Mathi
Augment Hololens’ Body Recognition And Tracking Capabilities Using Kinect, Krishna Chaithanya Mathi
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In this thesis, we are primarily interested in exploring the HoloLens technologies for medical practices. Particularly, we will address the limitation of HoloLens’ capability in human body sensing, recognition and tracking. We will then introduce and demonstrate the use of Kinect to augment HoloLens’ sensory and processing capabilities in order to produce time and space-synchronized immersive environment with both virtual body and real body of the same patient for supporting distributed medical collaborations. Specifically, we are looking at a distributed solution in which we are collecting the patient body data from Kinect, followed by body recognition and position/motion tracking processing …
Novel Cost And Space Efficient Range Of Motion And Gait Analysis Systems, Rutvik Bharatkumar Patel
Novel Cost And Space Efficient Range Of Motion And Gait Analysis Systems, Rutvik Bharatkumar Patel
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In this thesis, we have explored the use of the latest motion tracking technologies, as evident by Microsoft Xbox Kinect’s motion tracking capabilities, in combination with 3D digital human modeling and animation, multi-modality image capturing and processing, and fusion, to design a new generation of low-cost range of motion and gait analysis solutions that overcome the limitation of existing tools. The proposed solutions and our prototype systems have demonstrated accurate measurements and reliable analysis outcome compared to current clinic practices, with significantly reduced complexity and cost. Furthermore, it eliminates the need for expensive effort for pre- and post- processing of …
Adaptive Power Analog-To-Digital Interface For Digital Systems, Todd S. Grimes
Adaptive Power Analog-To-Digital Interface For Digital Systems, Todd S. Grimes
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Today many consumer, industrial, and military electronic systems are digital in nature and are utilized for multiple applications. Many of these systems were designed to be portable and generally have limited capabilities because of size, weight, and power requirements. The last several decades have seen the push for more power efficient electronics. Thus, researchers and scientists investigated advanced process technologies and more power efficient circuit implementations. This research is concerned with classes of applications intended to operate over long periods of time with a low duty cycle, but are subject to bursts of information, requiring high processing capabilities. Specifically, this …
Measuring Pulse Rate Variability During Motion Artifact With A Non-Contact, Multi-Imager Photoplethysmography System, Zachary Adam Kiehl
Measuring Pulse Rate Variability During Motion Artifact With A Non-Contact, Multi-Imager Photoplethysmography System, Zachary Adam Kiehl
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Non-contact imaging photoplethysmography is an exciting new field based on the principles of traditional photoplethysmography where viable signals can now be acquired without the use of contact equipment. Recent advances regarding non-contact imaging photoplethysmography have permitted a wide range of new possibilities focused on sensing the cardiopulmonary system. Physiological metrics such as pulse rate, respiration rate, and pulse rate variability can be obtained by current photoplethysmographic imaging methods. Although previous systems were challenged by head-motion artifacts, the mitigation of rigid head-motion artifacts has been demonstrated with a multi-imager design. This study investigated the feasibility and accuracy of pulse rate variability …