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Title: Blockchain inspired product authentication for supply chain security
Creator: Nitya Kriti, Fnu Nitya
Date: 2019
Collection: Electronic Theses & Dissertations
Description: In today's technologically advanced world, the prevalence of counterfeit products in the market is a major challenge. In every industry from pharmaceutical to the food industry, counterfeit products have a destructive impact on the health of the consumers as well as loss of jobs and lives of millions across the globe. This calls for a better system of product traceability to impede the introduction of counterfeit products in the market. This work proposes a method in which a blockchain...
Show moreIn today's technologically advanced world, the prevalence of counterfeit products in the market is a major challenge. In every industry from pharmaceutical to the food industry, counterfeit products have a destructive impact on the health of the consumers as well as loss of jobs and lives of millions across the globe. This calls for a better system of product traceability to impede the introduction of counterfeit products in the market. This work proposes a method in which a blockchain inspired system is implemented with the combination of the digital chain of information to the physical tag on the products. The physical tag has DNA of a known source to be privy to only select nodes and connected to the central database. The proposed method includes the use of magnetic stripe cards as product labels. This label is made to contain digital information, which is then coupled with the modified blockchain system. Pertaining to the high information density property of the magnetic stripe cards, partial DNA sequence information can be easily concatenated with the serial number of the product. This can also be re-programmed to track the route of the product along the supply chain. The main feature of the proposed method is the coupling of the re-programmability of the magnetic card labels with the physical DNA tag information contained on the label. The tag can be easily verified even after the product leaves the digital chain. Whilst, within the network coverage, the blockchain inspired tracking system can help track the route taken by the product. This mechanism of merging the physical information with the Internet of Things (IOT) shall address the situation of counterfeit products to an advanced degree of accuracy and reliability.
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Title: AN INTEGRATED OF CONTROL AND PROTECTION SCHEME FOR AC MICROGRIDS
Creator: AlZahrani, Saad Atitullah
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Numerous advances have occurred in the area of microgrids (MGs) in the last two decades. Protection is one of the most significant challenges facing the deployment of MGs. With the utilization of renewable energy resources (RES) to reduce emissions and costs, short circuit levels have drooped in comparison to those produced by conventional generating sources. Therefore, traditional protection schemes that apply to distribution system are no longer effective in protecting the microgrid against...
Show moreNumerous advances have occurred in the area of microgrids (MGs) in the last two decades. Protection is one of the most significant challenges facing the deployment of MGs. With the utilization of renewable energy resources (RES) to reduce emissions and costs, short circuit levels have drooped in comparison to those produced by conventional generating sources. Therefore, traditional protection schemes that apply to distribution system are no longer effective in protecting the microgrid against fault currents, either in grid–connected or islanded mode. In microgrid framework, distributed generation (DG) based RES require an interface of power electronic converters to regulate their output voltage, current, and frequency as well as to share the generated power properly. Mitigation the impacts of fault currents in microgrid system is an important aspect of restricting the output current of converters from exceeding their rated value, preventing power discontinuity, enhancing reliability of protection system and improving the stability of the network.For microgrid control and protection challenges, several approaches have been proposed in the last decade. However, the need for efficient and reliable protection schemes of islanded microgrid system still exists. This research thesis develops and synthesizes an adaptive integration of control and protection framework for MGs. The proposed strategy is based on detecting the faults and limiting the fault currents for short periods until the protection devices make a proper decision. A single state observer has been developed to detect the faults that occur within protection zones. Moreover, fault current limiter (FCL) devices have been utilized to achieve rapid switching with instant reduction of fault current contribution. The adaptive integrated protection proposed in this research is achievable using either centralized or decentralized control in MGs. The proposed framework has been applied to islanded microgrid configuration and is demonstrated to be an effective means to protect the system and maintain the voltage and frequency within acceptable range with the capability of power continuity during both transient and persistent faults.
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Title: When virtual reality meets IoT in the gym : enabling immersive and interactive machine exercise
Creator: Rabbi, Md. Fazlay
Date: 2016
Collection: Electronic Theses & Dissertations
Description: "The advent of head mounted displays (HMDs) such as Oculus Rift, Samsung Gear VR, and Microsoft HoloLens are turning immersive virtual reality (VR) into reality. As one of its most compelling applications, we envision that VR will revolutionize the personal fitness experience in our daily lives. Towards this vision, we present JARVIS, a novel immersive exercise tracking applications enabled by miniature IoT sensing devices combined with a mobile HMD device. By attaching IoT sensing devices on...
Show more"The advent of head mounted displays (HMDs) such as Oculus Rift, Samsung Gear VR, and Microsoft HoloLens are turning immersive virtual reality (VR) into reality. As one of its most compelling applications, we envision that VR will revolutionize the personal fitness experience in our daily lives. Towards this vision, we present JARVIS, a novel immersive exercise tracking applications enabled by miniature IoT sensing devices combined with a mobile HMD device. By attaching IoT sensing devices on any gym machines, JARVIS continuously tracks exercise progress and assesses exercise quality in real-time, enabling effective interaction with machines. By converting the captured exercise progress and quality information to VR inputs, it creates an immersive exercise experience with a virtual avatar to guide machine exercises. We have conducted extensive experiments to validate the performance of JARVIS. It achieves 97.96% of repetition segmentation accuracy without knowing the current exercise type, as well as 99.08% of exercise type recognition accuracy in 1.22 repetitions on average. We have also conducted a real-world deployment study to examine the efficacy of the proposed platform. By analyzing muscle activities using high-fidelity clinical surface Electromyography (sEMG) sensors, our results indicate that our VR/IoT-based platform could provide an engaging and effective guidance to exercisers for their strength training."--Page ii.
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Title: Simulations and silicon wafer compatibility of a voltage-controlled optical switch using ITO/NbOx
Creator: Burghardt, Kevin
Date: 2017
Collection: Electronic Theses & Dissertations
Description: The story of optics and processing has always been on of silicon devices making strides faster and cheaper than optics. The idea of creating optical switches has been generally relegated to academic exercises or niche markets. This research takes a view of optical processing that is complimentary to silicon. Silicon wafers produce extremely dense, high quality devices but producing truly 3D integrated circuits has been a challenge. It would be advantageous to not need to bond wafers to create...
Show moreThe story of optics and processing has always been on of silicon devices making strides faster and cheaper than optics. The idea of creating optical switches has been generally relegated to academic exercises or niche markets. This research takes a view of optical processing that is complimentary to silicon. Silicon wafers produce extremely dense, high quality devices but producing truly 3D integrated circuits has been a challenge. It would be advantageous to not need to bond wafers to create a 3D active structure. An argument for an optical switch that has a simple structure and uses industry established fabrication methods is given. The proposed switch uses the material indium tin oxide nanoparticles in niobum oxide glass (ITO/NbOx) as the active layer. The transmittance through this material is proportional to the electric field applied to it meaning the structure of a capacitor could be used to control it. It uses a metal for one plate of the capacitor and the ITO/NbOx as the other plate with the light running through ITO/NbOx plate. Each of the plates are separated from one another and surrounded by a dielectric material. Simulations show that silicon dioxide (SiO2) can be used effectively to turn the ITO/NbOx into a light guide with a transmittance controllable using an applied voltage and that the proposed structure can be created using industry established wafer fabrication processes.
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Title: Gaining value from smart meter data : power quality and outage event analysis
Creator: Johnson, Valdama E.
Date: 2016
Collection: Electronic Theses & Dissertations
Description: "Electric utility companies are making significant investments in smart grid technologies to improve the way power is generated and delivered to customers. Investments such as the replacement of electromechanical meters with smart meters has provided several benefits including more accurate electricity bills and the ability to remotely connect or disconnect service. In addition to these benefits, smart meters can also be used to address the lack of visibility into the electric distribution...
Show more"Electric utility companies are making significant investments in smart grid technologies to improve the way power is generated and delivered to customers. Investments such as the replacement of electromechanical meters with smart meters has provided several benefits including more accurate electricity bills and the ability to remotely connect or disconnect service. In addition to these benefits, smart meters can also be used to address the lack of visibility into the electric distribution system. While many utilities have visibility at substations through supervisory control and data acquisition systems, much of the distribution system beyond the substation remains unmonitored. The objective of this thesis is to show how utilities can gain more visibility into the distribution system by analyzing smart meter data. Smart meter outage events, when integrated into outage management systems, can help utilities locate outages faster and restore power to customers. In this thesis, smart meter outage events are compared with historical outage incidents from an outage management system. The results of the comparison show that there are several challenges to overcome before these events can be integrated into outage management systems. These challenges include processing momentary smart meter outages and ensuring that the electric model is correct. Smart meters can also be used to identify power quality issues such as drastic changes in voltage levels. An average voltage over a five-day period was obtained for 700,000 smart meters and roughly 1% had a voltage above the acceptable tolerance range. Many of these issues were caused by the failure of a distribution transformer or voltage regulator. By analyzing smart meter outage and voltage data, utilities can be more proactive in addressing customer and system issues."--Page ii.
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Title: Technology Assisted Smart Solar-System (TASS
Creator: Alforidi, Ahmad Fudy
Date: 2016
Collection: Electronic Theses & Dissertations
Description: This thesis focuses on the design, fabrications and testing of a Technology Assisted Smart Solar-System (TASS) that uses a solar panel both as an energy source and a sensor for tracking. A microcontroller, interfaced to a mini solar-cell array, was used to control and test the systems efficacy to track the light source employing (a) a motorized solar panel and (b) a robotic platform. The TASS packaging and printed circuit boards were designed and fabricated using 3-D inkjet printing. A roof...
Show moreThis thesis focuses on the design, fabrications and testing of a Technology Assisted Smart Solar-System (TASS) that uses a solar panel both as an energy source and a sensor for tracking. A microcontroller, interfaced to a mini solar-cell array, was used to control and test the systems efficacy to track the light source employing (a) a motorized solar panel and (b) a robotic platform. The TASS packaging and printed circuit boards were designed and fabricated using 3-D inkjet printing. A roof-top TASS was built to demonstrate an in- expensive application. The TASS developed in this work is also applicable to a light-tracking flowerpot for a smart home.
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Title: Fabrication of flexible micro-lens array for optical neural stimulation
Creator: Bi, Xiaopeng
Date: 2014
Collection: Electronic Theses & Dissertations
Description: Optogenetics is a fast growing neuromodulation technique which can remotely manipulate the specific activities of targeted neurons with irradiation of light. It benefits exploration of neuron network dynamics and also clinical studies such as retinal prosthesis. Light emitting diode (LED) offers a great option as the light source for optogenetics because it is small, reliable and easy to control. Especially, arrays of LEDs have been developed to enable multisite stimulation. A major drawback...
Show moreOptogenetics is a fast growing neuromodulation technique which can remotely manipulate the specific activities of targeted neurons with irradiation of light. It benefits exploration of neuron network dynamics and also clinical studies such as retinal prosthesis. Light emitting diode (LED) offers a great option as the light source for optogenetics because it is small, reliable and easy to control. Especially, arrays of LEDs have been developed to enable multisite stimulation. A major drawback of LED is its intrinsically low out-coupling efficiency of light as a result of a large emitting angle around 90° to 120°. In this thesis, the employment of μ-lens array has been proposed to couple with LED and target the improvement of light out-coupling efficiency, which will lead to a higher spatial resolution for optical neural stimulation. A number of techniques, including surface tension modification, soft lithography, thermal reflow, and self-organized dewetting, have been studied to fabricate the array of μ-lenses on a flexible polymer substrate. Surface morphology of such μ-lens array has been analyzed both experimentally and theoretically. Experiment in the medium of gelatin has been carried out to mimic the light irradiation property in the natural tissue.
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Title: 3D printed antennas : metalized plastic
Creator: Mohd Ghazali, Mohd Ifwat
Date: 2014
Collection: Electronic Theses & Dissertations
Description: This thesis introduces the use of 3D printed plastic structures for the fabrication of antenna structures. Use of 3D printing technology allows for a simple fabrication technique that is faster and low cost compared with traditional microfabrication approaches. Two Vivaldi antenna designs are studied first: i) a simple notch antenna with a radiating slot line cavity and ii) a corrugated Vivaldi with a partially covered cavity. The corrugations help increase the bandwidth and gain of the...
Show moreThis thesis introduces the use of 3D printed plastic structures for the fabrication of antenna structures. Use of 3D printing technology allows for a simple fabrication technique that is faster and low cost compared with traditional microfabrication approaches. Two Vivaldi antenna designs are studied first: i) a simple notch antenna with a radiating slot line cavity and ii) a corrugated Vivaldi with a partially covered cavity. The corrugations help increase the bandwidth and gain of the Vivaldi antenna. The antennas show an extremely wide bandwidth of approximately 13 GHz and have a gain maximum of approximately 12dB. Further modifications were made by adding bilateral pieces and dielectric focal lens at the radiating end. A larger bandwidth and higher gain was attained. The dielectric guiding structure in the aperture helps to further improve the gain both at the lower frequency and higher frequency regions. The integration of dielectrics in the antenna design is readily achieved using 3D printing. Apart from the above Vivaldi antenna designs, three other antenna designs were also studied. This includes a dielectric loaded monopole antenna, a patch antenna and a reconfigurable Lego-like antenna. Complex 3D antenna structures and novel antenna designs that use a combination of dielectric and metal regions are studied and these structures can readily be fabricated using 3D printing.
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Title: Defense against primary user emulation attacks in cognitive radio networks using advanced encryption standard
Creator: Alahmadi, Ahmed Salah
Date: 2014
Collection: Electronic Theses & Dissertations
Description: This thesis considers primary user emulation attacks (PUEA) in cognitive radio networks operating in the white spaces of the digital TV (DTV) band. We propose a reliable AES-assisted DTV scheme, in which an AES-encrypted reference signal is generated at the TV transmitter and used as the sync bits of the DTV data frames. By allowing a shared secret between the transmitter and the receiver, the reference signal can be regenerated at the receiver and used to achieve accurate identification of...
Show moreThis thesis considers primary user emulation attacks (PUEA) in cognitive radio networks operating in the white spaces of the digital TV (DTV) band. We propose a reliable AES-assisted DTV scheme, in which an AES-encrypted reference signal is generated at the TV transmitter and used as the sync bits of the DTV data frames. By allowing a shared secret between the transmitter and the receiver, the reference signal can be regenerated at the receiver and used to achieve accurate identification of the authorized primary users. Moreover, when combined with the analysis on the auto-correlation of the received signal, the presence of the malicious user can be detected accurately no matter the primary user is present or not. We analyze the effectiveness of the proposed approach through both theoretical analysis and simulation examples. It is shown that with the AES-assisted DTV scheme, the primary user, as well as malicious user, can be detected with high accuracy under primary user emulation attacks. It should be emphasized that the proposed scheme requires no changes in hardware or system structure except of a plug-in AES chip. Potentially, it can be applied directly to today's DTV system under primary user emulation attacks for more efficient spectrum sharing.
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Title: Accurate torque pulsation estimation and reduction of ipmsms valid for any operating point and current waveform
Creator: Ruekamnuaychok, Tiraruek
Date: 2019
Collection: Electronic Theses & Dissertations
Description: In this thesis, a method to estimate the torque pulsation of IPMSMs is proposed. The method is based on an analytical torque equation of IPMSMs derived by using the concepts of energy and co-energy of a magnetic circuit. This method is valid and accurate for any operating point, including that under heavy magnetic saturation, and for any arbitrary current waveform. Also, by using the proposed equation, a method to reduce the torque pulsation is proposed. Simulation and experimental results...
Show moreIn this thesis, a method to estimate the torque pulsation of IPMSMs is proposed. The method is based on an analytical torque equation of IPMSMs derived by using the concepts of energy and co-energy of a magnetic circuit. This method is valid and accurate for any operating point, including that under heavy magnetic saturation, and for any arbitrary current waveform. Also, by using the proposed equation, a method to reduce the torque pulsation is proposed. Simulation and experimental results show that the proposed methods, for both estimation and reduction, are valid, accurate and effective.
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Title: A comparison between PMSM rotor designs suitable for using ferrite magnets
Creator: Montalvo-Ortiz, Eduardo E.
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Increasing concerns over costs and supply of rare earth magnets have introduced more attention to Permanent Magnet Synchronous Machine (PMSM) designs that can work with ferrite magnets. Ferrite magnets have a major disadvantage in that they don't produce as much flux density as rare earth magnets do, which leads to lower torque density and thus less power in PMSMs. Several approaches have been taken in design of PMSMs in order to tackle this problem. Two of these designs are presented and...
Show moreIncreasing concerns over costs and supply of rare earth magnets have introduced more attention to Permanent Magnet Synchronous Machine (PMSM) designs that can work with ferrite magnets. Ferrite magnets have a major disadvantage in that they don't produce as much flux density as rare earth magnets do, which leads to lower torque density and thus less power in PMSMs. Several approaches have been taken in design of PMSMs in order to tackle this problem. Two of these designs are presented and compared in this work. The first design is the spoke-type (or Flux squeeze) PMSM which places the magnets radially in the rotor to increase the magnetic flux density in the airgap. The second design is the Permanent Magnet Assisted Synchronous Reluctance Machine (PMASynRM) which produces the majority of its torque from saliency and uses permanent magnets to produce an additional magnet torque component. The main metrics used to evaluate the performance of each design are: maximum torque, operating range, torque ripple, magnet material required, and efficiency. Finite Element Analysis (FEA) is used to simulate and analyze both designs. Experimental characterization results are shown for the spoke-type PMSM and are compared to the same results obtained with FEA in order to have a guideline as to how accurate the FEA results are. A prototype of the PMASynRM design was constructed in the laboratory and some experimental results are presented.
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Title: Power transfer between non-sinusoidal source and load across impedance network
Creator: Alshaabani, Abdulrhman
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Renewable energy sources are of immense interest as increasing their use is a potential method for climate change mitigation. Therefore, it is important to consider ways to improve the applications of renewable energies. In this thesis, the fundamentals of contactless power transformers are presented and discussed. The power transfer between a non-sinusoidal source and a non-sinusoidal load across an inductive network is a new model that can transfer different ranges of power without cables....
Show moreRenewable energy sources are of immense interest as increasing their use is a potential method for climate change mitigation. Therefore, it is important to consider ways to improve the applications of renewable energies. In this thesis, the fundamentals of contactless power transformers are presented and discussed. The power transfer between a non-sinusoidal source and a non-sinusoidal load across an inductive network is a new model that can transfer different ranges of power without cables. The main advantage of this new model of transferring power is that the reluctance transformer value is included when it is applied with compensation capacitors. In this thesis, the calculation of the resonant compensated capacitors' values includes the whole value of self-inductance with its reluctance. The power transfer system is applied to the high-power wind electric energy system. Consequently, the efficiency of transferring a high level of power is improved by applying the compensation capacitors. The MATHCAD software is used for calculating the analytical equations while the power transfer system simulation is carried out by the SABER software. -- Abstract.
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Title: Node localization via analyzing multi-path signals in ultrasonic sensor networks
Creator: Tomlinson, William J., Jr.
Date: 2013
Collection: Electronic Theses & Dissertations
Description: This thesis proposes a novel signal analysis based node localization strategy for sensor networks used in structural health monitoring (SHM) applications. The key idea is to analyze location-dependent multipath signal patterns in inter-node ultrasonic signals, and use machine-learning mechanisms to detect such patterns for accurate node localization on metal substrates on target structures. Majority of the traditional mechanisms rely on radio based Time Delay of Arrival (TDOA), coupled with...
Show moreThis thesis proposes a novel signal analysis based node localization strategy for sensor networks used in structural health monitoring (SHM) applications. The key idea is to analyze location-dependent multipath signal patterns in inter-node ultrasonic signals, and use machine-learning mechanisms to detect such patterns for accurate node localization on metal substrates on target structures. Majority of the traditional mechanisms rely on radio based Time Delay of Arrival (TDOA), coupled with multilateration, and multiple reference nodes. The proposed mechanism attempts to solve the localization problem in an ultrasonic sensor network (USN), avoiding the use of multiple reference beacon nodes. Instead, it relies on signal analysis and multipath signature classification from a single reference node that periodically transmits ultrasonic localization beacons. The approach relies on a key observation that the ultrasonic signal received at any point on the structure from the reference node, is a superposition of the signals received on the direct path and through all possible multi-paths. It is hypothesized that if the location of the reference node and the substrate properties are known a-priori, it should be possible to train a receiver (source node), to identify its own location by observing the exact signature of the received signal. To validate this hypothesis, steps were taken to develop a TI MSP430 based module for implementing a run-time system from a proposed architecture. Through extensive experimentation within an USN on the 2024 Aluminum substrate, it was demonstrated that localization accuracies up to 92% were achieved in the presence of varying spatial resolutions.
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Title: Contactless human activity recognition
Creator: Harrington, Brandon Lamont
Date: 2020
Collection: Electronic Theses & Dissertations
Description: The objective of this thesis is to design passive measurement and classification systems to recognize various human activities. Human Activity Recognition (HAR) can enhance a diverse range of human-centric applications in health care, smart homes, and security. Traditional solutions are based on wearable sensors and vision-based technologies; however, these solutions suffer from considerable limitations. The need for users to wear sensors for activity recognition is inconvenient and...
Show moreThe objective of this thesis is to design passive measurement and classification systems to recognize various human activities. Human Activity Recognition (HAR) can enhance a diverse range of human-centric applications in health care, smart homes, and security. Traditional solutions are based on wearable sensors and vision-based technologies; however, these solutions suffer from considerable limitations. The need for users to wear sensors for activity recognition is inconvenient and impractical for long periods of time. Contactless HAR systems have increased the abilities, practicality, and convenience of sensor based HAR systems. It allows for unobtrusive measurement and classification of sedentary behaviors in the workplace such as time spent sitting at desk, to intense physical activities such as at home exercises. This thesis provides contributions to contactless HAR methods and techniques using different sensing modalities. While activity recognition can be achieved with low cost ultrasound sensors, we show the beneficial impact of adopting radio frequency as a technological means of recognizing human activity. Specifically, WiFi signal analysis enables both macro and micro level activity classification. The ubiquity of WiFi infrastructures in home, university, work, and even outdoor environments makes WiFi the most convenient technology to produce valuable contributions in human activity recognition. The primary contributions of this work are: 1) Development of prototype hardware system, Echolocation Activity Detector (EAD), that achieves contactless activity recognition in office setting. 2) A low-cost system that employs WiFi monitoring of packets to provide a student engagement measure, and 3) Design of a non-invasive system that recognizes exercise activity and provides fine-grained repetition counting information of each exercise set using WiFi channel state information. Each of the contributions passively detects and classifies human activity in a contactless fashion without the need of wearable sensors.
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Title: Optimizing message to virtual link assignment in Avionics Full-Duplex Switched Ethernet networks
Creator: Klonowski, Joseph
Date: 2019
Collection: Electronic Theses & Dissertations
Description: "Avionics Full-Duplex Switched Ethernet (AFDX) is an Ethernet-based data network that provides deterministic performance, high reliability, and lower costs and development time by utilizing commercial off-the-shelf networking components. As AFDX networks have become of the network are continually being evaluated. There are two main types of solutions to improving network performance: changes to the physical layer and changes to the logical layer. Because the physical network is setup prior to...
Show more"Avionics Full-Duplex Switched Ethernet (AFDX) is an Ethernet-based data network that provides deterministic performance, high reliability, and lower costs and development time by utilizing commercial off-the-shelf networking components. As AFDX networks have become of the network are continually being evaluated. There are two main types of solutions to improving network performance: changes to the physical layer and changes to the logical layer. Because the physical network is setup prior to defining the data that is transferred on the network, logical layer optimization becomes important and is often the only viable solution. Previous research has explored optimization of different aspects of the logical solution for a given target (whether it be latency or bandwidth), however, an approach for a customizable target using optimization techniques has not been attempted. In this work, we provide an overview of AFDX networks and discuss factors engineers consider while optimizing the network. Previously researched solutions are evaluated for effectiveness. We identify the need for an optimization solution that allows for a customizable objective to account for both message latency and bandwidth. To fill this gap, we consider the problem of assigning messages to virtual links, which are configurable, logical unidirectional links from publishing end systems to one or more subscribing end systems. We propose a flexible framework based on particle swarm optimization (PSO) that performs message to virtual link assignment in AFDX networks to optimize a user-defined objective. We discuss and provide results on PSO optimization for a range of hyperparameters. Finally, results for a sample swarm are presented to prove the feasibility and usefulness of the proposed approach."--Page ii.
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Title: Terahertz photonic crystal microfluidic sensors
Creator: Acosta Silveira, Laura Cecilia
Date: 2014
Collection: Electronic Theses & Dissertations
Description: ABSTRACTTERAHERTZ PHOTONIC CRYSTAL MICROFLUIDIC SENSORSByLaura Cecilia Acosta SilveiraChallenges associated with meeting needs in the pharmaceutical industry, environment monitoring and food safety are in the interrogation of small volumes of samples with high sensitivity and specificity. The use of terahertz (THz) sensors is of significant interest due to its rich spectral content. The key focus of this research is to demonstrate THz microfluidic sensors for use in continuous...
Show moreABSTRACTTERAHERTZ PHOTONIC CRYSTAL MICROFLUIDIC SENSORSByLaura Cecilia Acosta SilveiraChallenges associated with meeting needs in the pharmaceutical industry, environment monitoring and food safety are in the interrogation of small volumes of samples with high sensitivity and specificity. The use of terahertz (THz) sensors is of significant interest due to its rich spectral content. The key focus of this research is to demonstrate THz microfluidic sensors for use in continuous flow monitoring that provide high sensitivity while using small volumes of samples. In order to achieve high sensitivity, photonic crystal (PC) based structures operating at the THz spectral region, are examined. One dimension (1D) PC devices with and without defect layers are designed for continuous flow characterization of liquids and vapors. For further improvement of the sensing capabilities a 3D PC sensor is also examined. The devices are built using alternating high and low permittivity materials with characteristics (material properties and thicknesses) that regulate the THz wave through transmission. When the air region is filled with a higher permittivity sample such as a liquid or vapor, the THz wave transmission through the PC is altered. In contrast to conventional sample holders, the use of PC enhances the change in transmitted signal due to the sample being loaded into the air gaps in the PC. This sensing configuration allows for high sensitivity while using a small volume of samples. A material characterization method is developed for 1D PC based sensor in order to extract the corresponding samples dielectric properties. Details of design, fabrication and characterization of photonic crystal terahertz microfluidic sensors are presented in this thesis.
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Title: Tracking single-units in chronic neural recordings for brain machine interface applications
Creator: Eleryan, Ahmed Ibrahim
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Ensemble recording of multiple single-unit activity has been used to study the mechanisms of neural population coding over prolonged periods of time, and to perform reliable neural decoding in neuroprosthetic motor control applications. However, there are still many challenges towards achieving reliable stable single-units recordings. One primary challenge is the variability in spike waveform features and firing characteristics of single units recorded using chronically implanted...
Show moreEnsemble recording of multiple single-unit activity has been used to study the mechanisms of neural population coding over prolonged periods of time, and to perform reliable neural decoding in neuroprosthetic motor control applications. However, there are still many challenges towards achieving reliable stable single-units recordings. One primary challenge is the variability in spike waveform features and firing characteristics of single units recorded using chronically implanted microelectrodes, making it challenging to ascertain the identity of the recorded neurons across days. In this study, I present a fast and efficient algorithm that tracks multiple single-units recorded in non-human primates performing brain control of a robotic limb, based on features extracted from units' average waveforms and interspike intervals histograms. The algorithm requires a relatively short recording duration to perform the analysis and can be applied at the start of each recording session without requiring the subject to be engaged in a behavioral task. The algorithm achieves a classification accuracy of up to 90% compared to manual tracking. I also explore using the algorithm to develop an automated technique for unit selection to perform reliable decoding of movement parameters from neural activity.
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Title: Segmented nano-force sensor
Creator: Dharuman, Gautham
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Nanoscale force sensors are finding widespread applications in atomic and biological force sensing where forces involved range from zeptonewtons to several nanonewtons. Different methods of nanoscale force sensing based on optical, electrical or purely mechanical schemes have been reported. However, each technique is limited by factors such as large size, low resolution, slow response, force range and alignment issues. In this research, a new device structure which could overcome the above...
Show moreNanoscale force sensors are finding widespread applications in atomic and biological force sensing where forces involved range from zeptonewtons to several nanonewtons. Different methods of nanoscale force sensing based on optical, electrical or purely mechanical schemes have been reported. However, each technique is limited by factors such as large size, low resolution, slow response, force range and alignment issues. In this research, a new device structure which could overcome the above mentioned constraints is studied theoretically and experimentally for the possibility of its application in nano-scale force sensing.
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Title: Reliability-based optimization of distribution system protection
Creator: Tian, Yuting
Date: 2014
Collection: Electronic Theses & Dissertations
Description: The power system is one of the most complex systems in existence. In any complex system, it is impossible to avoid abnormal operations. In order to reduce the impact of abnormal operations and to restore the system more quickly to normal states, many control and protection mechanisms are established. Protection systems consist of sensing and isolation devices that operate in the event of a fault to disconnect the part of the power system that is affected by the fault. However, malfunctions...
Show moreThe power system is one of the most complex systems in existence. In any complex system, it is impossible to avoid abnormal operations. In order to reduce the impact of abnormal operations and to restore the system more quickly to normal states, many control and protection mechanisms are established. Protection systems consist of sensing and isolation devices that operate in the event of a fault to disconnect the part of the power system that is affected by the fault. However, malfunctions can also occur within the protection system. Therefore, one objective of this thesis is to develop approaches for analyzing and modeling the reliability of power systems when the malfunctions of protection systems are considered. A methodology of evaluating reliability of distribution systems are presented. This method uses matrices to represent the relationship of devices in distribution systems and loads. Reliability indices such as SAIFI and SAIDI of the distribution system of IEEE-RBTS bus 2 are calculated using the proposed methodology. Since power utilities are aim to provide reliable electric power with low cost to customers, the investment of protective devices need to be taken into consideration. In this thesis, an optimization problem is presented. The objective in this optimization problem is the cost of disconnects and the constraint is the reliability indice, SAIDI. This reliability-based optimization problem is solved for RBTS distribution system by Genetic Algorithm (GA).
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Title: Fairness in AI-based recruitment and career pathway optimization
Creator: Mujtaba, Dena Freshta
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Work has long been a source of human livelihood, financial security, mental and physical well-being, dignity, and meaning. However, advances in computing, big data, artificial intelligence (AI), robotics, and related technologies are expected to usher in unprecedented and widespread changes in the economy and society. It is estimated that by 2030 up to 14% of the global workforce may need to change occupational categories as the world of work is disrupted by technological advances. Many...
Show moreWork has long been a source of human livelihood, financial security, mental and physical well-being, dignity, and meaning. However, advances in computing, big data, artificial intelligence (AI), robotics, and related technologies are expected to usher in unprecedented and widespread changes in the economy and society. It is estimated that by 2030 up to 14% of the global workforce may need to change occupational categories as the world of work is disrupted by technological advances. Many current and future workers that will enter the workforce lack skills that in-demand and future jobs require. In short, the landscape of work is poised for a major and unprecedentedly rapid transformation and this calls for a variety of strategies to meet the needs of workers, employers, the economy, and broader society.Motivated by these concerns, we investigate two key problems faced by organizations and workers in the future of work. As AI has expanded into human resource applications, organizations are increasingly using AI-based recruitment for sourcing, screening, and selecting talent. We explain how this can lead to biases in decisions and how this bias can be measured, review tools available for bias mitigation, and discuss future challenges for fairness in machine learning specific to recruitment applications. Alongside this, workers are affected not only by biased recruitment, but by the growing automation of tasks in occupations, which will increasingly require job and task transitions. To help workers navigate these transitions effectively, we propose a genetic-algorithm-based optimization engine to search for a worker's optimal career pathway in a network of occupations, given their current knowledge, skills, abilities, and other work-related characteristics. Overall, this thesis presents strategies for organizations to mitigate bias in AI-based recruitment and for workers to plan their career pathway in the face of unprecedented changes in the world of work.
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