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Item Turning Visual Noise Into Hardware Efficiency: Systems of Viewer and Content Aware Power-Quality Scalable Embedded Memories With ECC-Adaptation for Big Videos and Deep Learning(North Dakota State University, 2021) Haidous, Ali AhmadMobile devices, such as smart phones, are being increasingly utilized for watching videos. Video processing requires frequent memory access that consume a significant amount of power due to large data size and intensive computational requirements. This limits battery life and frustrates users. Memory designers are focused on hardware-level power-optimization techniques without consideration of how hardware performance influences viewers' actual experience. The human visual system is limited in its ability to detect subtle degradations in image quality. For example, under conditions of high ambient illumination – such as outdoors in direct sunlight – the veiling luminance (i.e., glare) on the screen of a mobile device can effectively mask imperfections in the image. Under these circumstances, a video can be rendered in lower than full quality without the viewer being able to detect any difference in quality. As a result, the isolation between hardware design and viewer experience significantly increases hardware implementation overhead and power consumption due to overly pessimistic design margins, while integrating the two would have the opposite effect. In this dissertation, viewer-awareness, content-awareness, and hardware adaptation are integrated to achieve power optimization without degrading video quality, as perceived by users. Specifically, this dissertation will (i) experimentally and mathematically connect viewer experience, ambient illuminance, and memory performance; (ii) develop energy-quality adaptive hardware that can adjust memory usage based on ambient luminance to reduce power usage without impacting viewer experience; (iii) design various mobile video systems to fully evaluate the effectiveness of the developed methodologies; and (iv) provide an overview of bleeding edge related area research then push the boundary further using the novel techniques discussed to achieve optimized quality, silicone area overhead, and power reduction in video memory.Item A New Method of Dynamic Reliability Management for Chip Multi-Processors(North Dakota State University, 2014) Yamamoto, Alexandre YasuoThis work presents a new dynamic reliability management controller which successfully extends the expected lifetime of Chip Multi-Processors (CMPs). This is achieved by migrating tasks within the CMP, effectively reducing core wear and temperature. While this does decrease performance, results obtained show that the performance penalty is below 10% while lifetime expectancy increases are above 30%. The estimation of lifetime is done by using a full system simulator to obtain execution, power and temperature traces, and then feeding this data to the REliability eSTimation (REST) tool. REST uses a Monte Carlo based algorithm to estimate the Mean Time To Failure (MTTF) of the CMP according to aging mechanisms which affect the transistors.Item FPGA-Based Simulation and Implementation of Induction Motor Torque Control Systems Based on Direct Torque Control (DTC)(North Dakota State University, 2014) Abdollahzadeh Zare, MohammadElectric drives for induction machines are of great importance because of the popularity of this machine type. To design, simulate and implement such drives, fast, reliable digital signal processors are needed. Recently Field Programmable Gate Array (FPGA) has been used in electric drive applications. This is mostly because of higher flexibility of hardware solutions compared to software solutions. In this thesis, FPGA-based simulation and implementation of direct torque control (DTC) of induction motors are studied. DTC is simulated on an FPGA as well as a personal computer. Results prove the FPGA-based simulation to be 12 times faster. Also an experimental setup of DTC is implemented using both FPGA and dSPACE. The FPGA-based design provides a potential sampling frequency of 800 kHz. This is a breakthrough knowing that a low ripple DTC is highly dependent on high sampling frequencies. Finally, a configurable torque/speed control system is designed and implemented on dSPACE.Item High-Power, High-Efficiency, Multi-Functional CMOS Radio Frequency Integrated Circuit for Wireless Communication of Unmanned Aircraft System(North Dakota State University, 2017) Roy, PalashRecently the Unmanned Aircraft System (UAS) has become very popular due to its current and projected opportunities in diversified applications from surveillance to security to militry. The Federal Aviation Administration (FAA) has mandated for all UASs to be equipped with an Automatic Dependent Surveillance Broadcast (ADS-B) transmitter by 2020. ADS-B is a next generation aircraft communication system, operating with two frequencies, 978 MHZ and 1090 MHz, which will transmit the information of identification, and precise position of an airplane to the nearby airplanes and ground station. At present, the ADS-B transmitter is fabricated with hybrid integrated circuits (HICs) in three different modules: a Phase Locked Loop (PLL) module, an Up-converter (modulator) module and a Power Amplifier (PA) module [8-10] which makes the system very large in size and expensive. In this work, for the first time an ADS-B transmitter as a part of Universal Access Transceievr (UAT) and Universal Beacon Radio (UBR) has beeen developed in a fully integrated single chip using the Complementary Metal Oxide Semiconductor (CMOS) process which is capable of operating both at 978 MHz UAT and 1090 MHz Extended Squitter (ES) modes. The chip provides the modulated output power of 23 dBm which is sufficient for the UAS to operate below class-A airspace. If the UAS needs to operate above this range or needs to operate for a manned aircraft system, this single chip ADS-B transmitter can be interfaced to drive an off-chip high-power PA, and, thus, it will reduce the burden of the input power and the gain of the off-chip PA. The chip supports both single tone and modulated baseband signals. In addition, this chip is capable of operating a part of new datalinks (960 MHz to 1164 MHz) and DME bands for UAS.Item Metamaterial-Inspired Reconfigurable Series-Fed Arrays(North Dakota State University, 2014) Ijaz, BilalOne of the biggest challenges in modern day wireless communication systems is to attain agility and provide more degrees of freedom in parameters such as frequency, radiation pattern and polarization. Existing phased array antenna technology has limitations in frequency bandwidth and scan angle. So it is important to design frequency reconfigurable antenna arrays which can provide two different frequency bandwidths with a broadside radiation pattern having a lower sidelobe and reduced frequency scanning. The reconfigurable antenna array inspired by the properties of metamaterials presented here provides a solution to attain frequency agility in a wireless communication system. The adaptive change in operating frequency is attained by using RF p-i-n diodes on the antenna array. The artificially made materials having properties of negative permeability and negative permittivity have antiparallel group and phase velocities, and, in consequence of that, they support backward wave propagation. The key idea of this work is to demonstrate that the properties of metamaterial non-radiating phase shifting transmission lines can be utilized to design a series-fed antenna array to operate at two different frequency bands with a broadside radiation pattern in both configurations. In this research, first, a design of a series-fed microstrip array with composite right/left-handed transmission lines (CRLH-TLs) is proposed. To ensure that each element in the array is driven with the same voltage phase, dual-band CRLH-TLs are adopted instead of meander-line microstrip lines to provide a compact interconnect with a zero phase-constant at the frequency of operation. Next, the work is extended to design a reconfigurable series-fed antenna array with reconfigurable metamaterial interconnects, and the expressions for array factor are derived for both switching bands.Item An Active Power Supply Filter with Ultra Wide Bandwidth(North Dakota State University, 2016) Booth, BrianAn active transformerless common mode filter is designed for use with switching mode power supplies with a switching frequency greater than 1MHz. The filter utilizes an amplifier in a voltage sensing current adjusting architecture to cancel out common mode noise generated by the switching power supply. The filter is analyzed using a transfer function, simulation, and measurements. Several possible feedback configurations are examined and benefits of different configurations are explained. The active filter is shown to have superior performance to only passive components at frequencies up to 20MHz. Spectral domain, time domain, and S21 measurements are given to show the filter’s effectiveness.Item Dummy TSV-Based Timing Optimization for 3D On-Chip Memory(North Dakota State University, 2016) Pourbakhsh, Seyed AlirezaDesign and fabrication of three-dimensional (3D) ICs is one the newest and hottest trends in semiconductor manufacturing industry. In 3D ICs, multiple 2D silicon dies are stacked vertically, and through silicon vias (TSVs) are used to transfer power and signals between different dies. The electrical characteristic of TSVs can be modeled with equivalent circuits consisted of passive elements. In this thesis, we use “dummy” TSVs as electrical delay units in 3D SRAMs. Our results prove that dummy TSVs based delay units are as effective as conventional delay cells in performance, increase the operational frequency of SRAM up to 110%, reduce the usage of silicon area up to 88%, induce negligible power overhead, and improve robustness against voltage supply variation and fluctuation.Item A Variable High Gain and High Dynamics Range CMOS Phase Shifter for Phased Array Antenna Applications(North Dakota State University, 2016) Mitra, DipankarPhase shifters can adjust phases electronically and hence is very popular for phased array antenna applications where radiation angle can be scanned electronically avoiding bulky mechanical rotation arrangement. In this research a variable gain phase shifter was investigated, capable of controlling precisely both phase and gain simultaneously. The phase shifter was fabricated using 0.18um CMOS process and the measured results showed continuous phase shift of 3030 with 9-dB variable gain at 3.5 GHz. Based on the measured results, a modified phase shifter was proposed and designed which can achieve continuous phase rotation of 3600 with small 22.50 steps, a low RMS phase error of 20 providing high resolution, a very high conversion gain of 14.2 dB with dynamic gain control range of 20 dB. These performances will create a potential future for smart communication radar applications where both beamforming and nulling can be achieved.Item Utilizing Recommender Systems as an Analysis Tool for Measuring Network Dynamics(North Dakota State University, 2015) Usman Shahid Khan, MuhammadRecommender systems apply numerous knowledge discovery techniques to suggest the preferred products, information, or service on contextual data. In our study, we utilize the recommender system for analyzing and measuring the network dynamics. The dynamic factors such as change in network shape or data size affect the performance of the networks and make it harder for the optimization techniques to be used for finding the optimum solution. In our research, we focused on the monitoring and analyzing the dynamic factors involved in two networks: (a) body area networks and (b) road networks; and based on the study proposed the efficient solution for mitigating the negative effects of the dynamic factors involved using recommender systems. In body area networks, we monitored the dynamically changing body area sensors data and studied the correlation between the sensors’ location and activity recognition. We proposed a cloud based framework that has employed a feature descriptor called Local Energy-based Shape Histogram (LESH) to preserve the maximum information of local energy. We have also used the Wearable Action Recognition Database (WARD) dataset to perform the experiments. Based on our study we proposed the best combination of sensors for various activities recognition. In road networks, we monitored the congestion during large-scale emergency evacuation and proposed efficient route recommendation service that helps in fast and safe evacuation. To respond to emergencies in a fast and an effective manner, it is of critical importance to have efficient evacuation plans that lead to minimum road congestion. The existing approaches, mostly based on multi-objective optimizations, are not scalable enough when involve numerous time varying parameters, such as traffic volume, safety status, and weather conditions. In this study, we propose a new scalable emergency evacuation service that recommends the evacuees with the most preferred routes towards safe locations during a disaster. The evacuees are directed towards those routes that are safe and have least congestion resulting in decreased evacuation time. The results indicated the improved efficiency of our service for average evacuation times and evacuation delays.Item The Capacity Region of the Gaussian Z-Interference Channel with Gaussian Input and Weak Interference(North Dakota State University, 2016) Sarkar, AvikWe consider a wireless communication scenario with two transmit-receive pairs where each of the transmitters has a message for its corresponding receiver and only one of the receivers face interference from the undesired transmitter. In our research, we focused on devising optimal ways to manage this undesired interference and characterize the best communication rates for both transmit-receive pairs. Currently, this problem of interference is dealt with by restricting the two communications in di erent frequency or time bands. We explore the possibility of achieving better rates by allowing them to operate in the same band. Such channels were identi ed about 4 decades ago, but the maximum rate of communication when the transmitters have a power constraint is still unknown. In this work, we characterize the best rates for this channel under a reasonable practical constraint of using Gaussian signals at both the transmitters.