Matching Items (4)
Description
Negative bias temperature instability (NBTI) and channel hot carrier (CHC) are important reliability issues impacting analog circuit performance and lifetime. Compact reliability models and efficient simulation methods are essential for circuit level reliability prediction. This work proposes a set of compact models of NBTI and CHC effects for analog and mixed-signal circuit, and a direct prediction method which is different from conventional simulation methods. This method is applied in circuit benchmarks and evaluated. This work helps with improving efficiency and accuracy of circuit aging prediction.
ContributorsZheng, Rui (Author) / Cao, Yu (Thesis advisor) / Yu, Hongyu (Committee member) / Bakkaloglu, Bertan (Committee member) / Arizona State University (Publisher)
Created2011
Description
Bipolar commercial-off-the-shelf (COTS) circuits are increasingly used in spacemissions due to the low cost per part. In space environments these devices are exposed to
ionizing radiation that degrades their performance. Testing to evaluate the performance of
these devices is a costly and lengthy process. As such methods that can help predict a
COTS part’s performance help alleviate these downsides. A modeling software for
predicting total ionizing dose (TID), enhanced low dose rate sensitivity (ELDRS), and
hydrogen gas on bipolar parts is introduced and expanded upon. The model is then
developed in several key ways that expand it’s features and usability in this field. A
physics based methodology of simulating interface traps (NIT) to expand the previously
experimental only database is detailed. This new methodology is also compared to
experimental data and used to establish a link between hydrogen concentration in the
oxide and packaged hydrogen gas. Links are established between Technology Computer
Aided Design (TCAD), circuit simulation, and experimental data. These links are then
used to establish a better foundation for the model. New methodologies are added to the
modeling software so that it is possible to simulate transient based characteristics like
slew rate.
ContributorsRoark, Samuel (Author) / Barnaby, Hugh (Thesis advisor) / Sanchez Esqueda, Ivan (Committee member) / Bakkaloglu, Bertan (Committee member) / Arizona State University (Publisher)
Created2022
Description
In 1946 Felix Bloch first demonstrated the phenomenon of nuclear magnetic resonance using continuous-wave signal generation and acquisition. Shortly after in 1966, Richard R. Ernst demonstrated the breakthrough that nuclear magnetic resonance needed to develop into magnetic resonance imaging: the application of Fourier transforms for sensitive pulsed imaging. Upon this discovery, the world of research began to develop high power radio amplifiers and fast radio switches for pulsed experimentation. Consequently, continuous-wave imaging placed on the backburner.Although high power pulses are dominant in clinical imaging, there are unique advantages to low power, continuous-wave pulse sequences that transmit and receive signals simultaneously. Primarily, tissues or materials with short T2 time constants can be imaged and the peak radio power required is drastically reduced.
The fundamental problem with this lies in its nature; the transmitter leaks a strong leakage signal into the receiver, thus saturating the receiver and the intended nuclear magnetic resonance signal is lost noise.
Demonstrated in this dissertation is a multichannel standalone simultaneous transmit and receive (STAR) system with remote user-control that enables continuous- wave full-duplex imaging. STAR calibrates cancellation signals through vector modulators that match the leakage signal of each receiver in amplitude but opposite in phase, therefore destructively interfering the leakage signals. STAR does not require specific imaging coils or console inputs for calibration. It was designed to be general- purpose, therefore integrating into any imaging system. To begin, the user uses an Android tablet to tune STAR to match the Larmor frequency in the bore. Then, the user tells STAR to begin calibration. After self-calibrating, the user may fine-tune the calibration state of the system before enabling a low-power mode for system electronics and imaging may commence. STAR was demonstrated to isolate two receiver coils upwards of 70 dB from the transmit coil and is readily upgradable to enable the use of four receive coils.
Some primary concerns of STAR are the removal of transceivers for multichannel operation, digital circuit noise, external noise, calibration speed, upgradability, and the isolation introduced; all of which are addressed in the proceeding thesis.
ContributorsColwell, Zachary Allen (Author) / Sohn, Sung-Min (Thesis advisor) / Trichopoulos, Georgios (Thesis advisor) / Aberle, James (Committee member) / Sadleir, Rosalind (Committee member) / Arizona State University (Publisher)
Created2023
Description
Before the digital age, architectural representation in drawing resulted from two transformational processes: one happened with the author as they developed the drawing from an idea to material. The second happened with the viewer as they interpreted the drawing. In these processes, a particular medium, the frame, raises the status of ideas—the frame functions as an organizing principle that unifies the artist’s intentions and practice. Today digital drawing has mostly replaced annotated drawing, and in the exchange, the benefit of the frame is lost.This qualitative study utilizes a conceptual approach to observe the frame and propose a methodology to bring together the analog/physical frame and the digital/immersive frame. The study enters a dialog with the art theorist Rosalind Krauss who writes about the “Institution of the Frame,” and the art historian Svetlana Alpers who classifies two different modes of representing the world—the Albertian and the Keplerian. Following Krauss’ statement, the study argues that a frame is an act of excision. Inspired by Alpers’ classification, the study focuses on creating two modes of frames, the Alberti and the Brunelleschi. The Alberti mode considers the frame a veil—a two-dimensional surface. Brunelleschi mode observes the frame as a fold—a three-dimensional surface.
The study utilizes several analytical methods: descriptive writing, graphic diagramming, and the production of drawings that unite the analog and digital as physical spaces and cinematic screens. These methods develop from the work of Luke Winslow in Frame Analysis, which provides a three-step “meaning-making process” to dissect multiple materials as an interdisciplinary framework. The study examines eight cases studies to identify systematic and generalizable principles, distinguish the relationship between analog and digital frames, and illuminate a strategy to build a delay in the process of thinking about architectural design in the digital age. The conclusion offers an approach for interfacing analog and digital frames in architecture while reflecting on the results, the significance of the interdisciplinary research study, and a position statement—the very essence of the research.
ContributorsRocchi, Elena (Author) / Davids Scott, Jason (Thesis advisor) / Hedberg Olenina, Ana (Committee member) / Bernstein, Max (Committee member) / Arizona State University (Publisher)
Created2022