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A New Method of Dynamic Reliability Management for Chip Multi-Processors
(North Dakota State University, 2014) Yamamoto, Alexandre Yasuo
This 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.
FPGA-Based Simulation and Implementation of Induction Motor Torque Control Systems Based on Direct Torque Control (DTC)
(North Dakota State University, 2014) Abdollahzadeh Zare, Mohammad
Electric 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.
An Active Power Supply Filter with Ultra Wide Bandwidth
(North Dakota State University, 2016) Booth, Brian
An 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.
Dummy TSV-Based Timing Optimization for 3D On-Chip Memory
(North Dakota State University, 2016) Pourbakhsh, Seyed Alireza
Design 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.
A Variable High Gain and High Dynamics Range CMOS Phase Shifter for Phased Array Antenna Applications
(North Dakota State University, 2016) Mitra, Dipankar
Phase 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.
The Capacity Region of the Gaussian Z-Interference Channel with Gaussian Input and Weak Interference
(North Dakota State University, 2016) Sarkar, Avik
We 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.
Refinementbased Verification of Elastic Pipelined System with Early Evaluation
(North Dakota State University, 2010) Cai, Yangwei
This thesis presents a formal verification procedure to check correctness of the synchronous elastic pipelined system that incorporates early evaluation against its synchronous parent system. Note that the goal of the verification procedure is not to establish the correctness of the algorithm for synthesizing elastic circuits, but instead, to find bugs and formally prove the correctness of elasticized designs with early evaluation. Dataflow through elastic architectures is complicated by the insertion of any number of elastic buffers in any place in the design. Elastic token-flow diagrams are introduced, which are used to track the flow of data in elastic architectures. We provide a method to construct such diagrams. The thesis also develops a highly automated and systematic procedure based on elastic token-flow diagrams that compute functions that map states of elastic systems to states of the synchronous parent systems. Such functions, known as refinement maps, are used to compare behaviors of elastic and synchronous systems and hence prove their equivalence. The effectiveness of this method is demonstrated by verifying 8 synchronous elastic pipelined processor models with early evaluation.
Wireless Health Monitor Design
(North Dakota State University, 2012) Koziy, Kostyantyn V.
In this thesis, a Wireless Health Monitor system for novel spacesuit verification and tests is presented. This system monitors the operator's health-related vital parameters and incorporates data acquisition, collecting and processing, wireless transmission, data displaying and logging. Power-saving technics for battery-powered applications are incorporated. A proprietary communication protocol for multi-node wireless network is developed and integrated. An embedded web interface for system control and data monitoring is utilized to achieve platform independence and reliability. Calculations and simulation results for the algorithms developed for gas flow measurements are presented. Packaging for this system, sensor calibration procedures, final device characteristics, specifications and field test results are described. Finally, future work toward possible device operation, improvement, and additional features is considered.
Automating the design of deep learning models using neural architecture search for medical image classification
(North Dakota State University, 2024) Balamurugan, Ridhanya
Designing Deep Learning (DL) models for medical image classification tasks poses significant challenges, demanding substantial expertise owing to the intricate nature and critical importance of the undertaking. Creating a DL model tailored for such purposes entails iterative processes of designing, implementing, and fine-tuning algorithms to achieve optimal performance. To mitigate these difficulties, Neural Architecture Search (NAS) has risen as a key field to generate the most effective DL models automatically. However, much of the previous studies involving NAS focus on automating the design of DL models for well-established datasets such as CIFAR-10 and ImageNet. This technique should also be extended to medical image datasets where detecting crucial features accurately in medical images is essential to detect specific illnesses correctly. Therefore, in this study, we investigate NAS to autonomously design best performing DL models for skin lesion detection, thereby demonstrating its usefulness for additional medical image classification endeavours.
A New Generation of Particle-Based Radio Frequency (RF) Switches for Portable and High-Frequency Applications
(North Dakota State University, 2019) Soufizadeh Balaneji, Nasim
Reconfigurable and tunable designs which provide multi-functionality are highly desirable in wireless communication systems. Amongst different methodologies to design RF switching, a directly connected biasing circuitry is not required for Static Field Micro-Particle Components (SFM-PCs); therefore, not only power consumption is lowered but also these particle-based switches can be used in complex geometries. However, the traditional structure has low-frequency bandwidth for both ON and OFF states and fails to operate correctly when undergoing rotation, these result in difficulties in using them in portable higher band applications. To address these issues, here two new techniques to increase the frequency bandwidth of ON and OFF states were proposed. Furthermore, a novel 360-degree rotatable structure was developed. The efficacy of these structures were evaluated by embedding them into discontinuous microstrip transmission lines. Both HFSS simulations and measurements show the accuracy of the analysis and the efficacy of the proposed designs.

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