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Description
Digital sound synthesis allows the creation of a great variety of sounds. Focusing on interesting or ecologically valid sounds for music, simulation, aesthetics, or other purposes limits the otherwise vast digital audio palette. Tools for creating such sounds vary from arbitrary methods of altering recordings to precise simulations of vibrating

Digital sound synthesis allows the creation of a great variety of sounds. Focusing on interesting or ecologically valid sounds for music, simulation, aesthetics, or other purposes limits the otherwise vast digital audio palette. Tools for creating such sounds vary from arbitrary methods of altering recordings to precise simulations of vibrating objects. In this work, methods of sound synthesis by re-sonification are considered. Re-sonification, herein, refers to the general process of analyzing, possibly transforming, and resynthesizing or reusing recorded sounds in meaningful ways, to convey information. Applied to soundscapes, re-sonification is presented as a means of conveying activity within an environment. Applied to the sounds of objects, this work examines modeling the perception of objects as well as their physical properties and the ability to simulate interactive events with such objects. To create soundscapes to re-sonify geographic environments, a method of automated soundscape design is presented. Using recorded sounds that are classified based on acoustic, social, semantic, and geographic information, this method produces stochastically generated soundscapes to re-sonify selected geographic areas. Drawing on prior knowledge, local sounds and those deemed similar comprise a locale's soundscape. In the context of re-sonifying events, this work examines processes for modeling and estimating the excitations of sounding objects. These include plucking, striking, rubbing, and any interaction that imparts energy into a system, affecting the resultant sound. A method of estimating a linear system's input, constrained to a signal-subspace, is presented and applied toward improving the estimation of percussive excitations for re-sonification. To work toward robust recording-based modeling and re-sonification of objects, new implementations of banded waveguide (BWG) models are proposed for object modeling and sound synthesis. Previous implementations of BWGs use arbitrary model parameters and may produce a range of simulations that do not match digital waveguide or modal models of the same design. Subject to linear excitations, some models proposed here behave identically to other equivalently designed physical models. Under nonlinear interactions, such as bowing, many of the proposed implementations exhibit improvements in the attack characteristics of synthesized sounds.
ContributorsFink, Alex M (Author) / Spanias, Andreas S (Thesis advisor) / Cook, Perry R. (Committee member) / Turaga, Pavan (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created2013
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Description
The processing power and storage capacity of portable devices have improved considerably over the past decade. This has motivated the implementation of sophisticated audio and other signal processing algorithms on such mobile devices. Of particular interest in this thesis is audio/speech processing based on perceptual criteria. Specifically, estimation of parameters

The processing power and storage capacity of portable devices have improved considerably over the past decade. This has motivated the implementation of sophisticated audio and other signal processing algorithms on such mobile devices. Of particular interest in this thesis is audio/speech processing based on perceptual criteria. Specifically, estimation of parameters from human auditory models, such as auditory patterns and loudness, involves computationally intensive operations which can strain device resources. Hence, strategies for implementing computationally efficient human auditory models for loudness estimation have been studied in this thesis. Existing algorithms for reducing computations in auditory pattern and loudness estimation have been examined and improved algorithms have been proposed to overcome limitations of these methods. In addition, real-time applications such as perceptual loudness estimation and loudness equalization using auditory models have also been implemented. A software implementation of loudness estimation on iOS devices is also reported in this thesis. In addition to the loudness estimation algorithms and software, in this thesis project we also created new illustrations of speech and audio processing concepts for research and education. As a result, a new suite of speech/audio DSP functions was developed and integrated as part of the award-winning educational iOS App 'iJDSP." These functions are described in detail in this thesis. Several enhancements in the architecture of the application have also been introduced for providing the supporting framework for speech/audio processing. Frame-by-frame processing and visualization functionalities have been developed to facilitate speech/audio processing. In addition, facilities for easy sound recording, processing and audio rendering have also been developed to provide students, practitioners and researchers with an enriched DSP simulation tool. Simulations and assessments have been also developed for use in classes and training of practitioners and students.
ContributorsKalyanasundaram, Girish (Author) / Spanias, Andreas S (Thesis advisor) / Tepedelenlioğlu, Cihan (Committee member) / Berisha, Visar (Committee member) / Arizona State University (Publisher)
Created2013
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Description
ABSTRACT The D flip flop acts as a sequencing element while designing any pipelined system. Radiation Hardening by Design (RHBD) allows hardened circuits to be fabricated on commercially available CMOS manufacturing process. Recently, single event transients (SET's) have become as important as single event upset (SEU) in radiation hardened high

ABSTRACT The D flip flop acts as a sequencing element while designing any pipelined system. Radiation Hardening by Design (RHBD) allows hardened circuits to be fabricated on commercially available CMOS manufacturing process. Recently, single event transients (SET's) have become as important as single event upset (SEU) in radiation hardened high speed digital designs. A novel temporal pulse based RHBD flip-flop design is presented. Temporally delayed pulses produced by a radiation hardened pulse generator design samples the data in three redundant pulse latches. The proposed RHBD flip-flop has been statistically designed and fabricated on 90 nm TSMC LP process. Detailed simulations of the flip-flop operation in both normal and radiation environments are presented. Spatial separation of critical nodes for the physical design of the flip-flop is carried out for mitigating multi-node charge collection upsets. The proposed flip-flop is also used in commercial CAD flows for high performance chip designs. The proposed flip-flop is used in the design and auto-place-route (APR) of an advanced encryption system and the metrics analyzed.
ContributorsKumar, Sushil (Author) / Clark, Lawrence (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Ogras, Umit Y. (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Switch mode DC/DC converters are suited for battery powered applications, due to their high efficiency, which help in conserving the battery lifetime. Fixed Frequency PWM based converters, which are generally used for these applications offer good voltage regulation, low ripple and excellent efficiency at high load currents. However at light

Switch mode DC/DC converters are suited for battery powered applications, due to their high efficiency, which help in conserving the battery lifetime. Fixed Frequency PWM based converters, which are generally used for these applications offer good voltage regulation, low ripple and excellent efficiency at high load currents. However at light load currents, fixed frequency PWM converters suffer from poor efficiencies The PFM control offers higher efficiency at light loads at the cost of a higher ripple. The PWM has a poor efficiency at light loads but good voltage ripple characteristics, due to a high switching frequency. To get the best of both control modes, both loops are used together with the control switched from one loop to another based on the load current. Such architectures are referred to as hybrid converters. While transition from PFM to PWM loop can be made by estimating the average load current, transition from PFM to PWM requires voltage or peak current sensing. This theses implements a hysteretic PFM solution for a synchronous buck converter with external MOSFET's, to achieve efficiencies of about 80% at light loads. As the PFM loop operates independently of the PWM loop, a transition circuit for automatically transitioning from PFM to PWM is implemented. The transition circuit is implemented digitally without needing any external voltage or current sensing circuit.
ContributorsVivek, Parasuram (Author) / Bakkaloglu, Bertan (Thesis advisor) / Ogras, Umit Y. (Committee member) / Song, Hongjiang (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Super-Resolution (SR) techniques are widely developed to increase image resolution by fusing several Low-Resolution (LR) images of the same scene to overcome sensor hardware limitations and reduce media impairments in a cost-effective manner. When choosing a solution for the SR problem, there is always a trade-off between computational efficiency and

Super-Resolution (SR) techniques are widely developed to increase image resolution by fusing several Low-Resolution (LR) images of the same scene to overcome sensor hardware limitations and reduce media impairments in a cost-effective manner. When choosing a solution for the SR problem, there is always a trade-off between computational efficiency and High-Resolution (HR) image quality. Existing SR approaches suffer from extremely high computational requirements due to the high number of unknowns to be estimated in the solution of the SR inverse problem. This thesis proposes efficient iterative SR techniques based on Visual Attention (VA) and perceptual modeling of the human visual system. In the first part of this thesis, an efficient ATtentive-SELective Perceptual-based (AT-SELP) SR framework is presented, where only a subset of perceptually significant active pixels is selected for processing by the SR algorithm based on a local contrast sensitivity threshold model and a proposed low complexity saliency detector. The proposed saliency detector utilizes a probability of detection rule inspired by concepts of luminance masking and visual attention. The second part of this thesis further enhances on the efficiency of selective SR approaches by presenting an ATtentive (AT) SR framework that is completely driven by VA region detectors. Additionally, different VA techniques that combine several low-level features, such as center-surround differences in intensity and orientation, patch luminance and contrast, bandpass outputs of patch luminance and contrast, and difference of Gaussians of luminance intensity are integrated and analyzed to illustrate the effectiveness of the proposed selective SR frameworks. The proposed AT-SELP SR and AT-SR frameworks proved to be flexible by integrating a Maximum A Posteriori (MAP)-based SR algorithm as well as a fast two-stage Fusion-Restoration (FR) SR estimator. By adopting the proposed selective SR frameworks, simulation results show significant reduction on average in computational complexity with comparable visual quality in terms of quantitative metrics such as PSNR, SNR or MAE gains, and subjective assessment. The third part of this thesis proposes a Perceptually Weighted (WP) SR technique that incorporates unequal weighting parameters in the cost function of iterative SR problems. The proposed approach is inspired by the unequal processing of the Human Visual System (HVS) to different local image features in an image. Simulation results show an enhanced reconstruction quality and faster convergence rates when applied to the MAP-based and FR-based SR schemes.
ContributorsSadaka, Nabil (Author) / Karam, Lina J (Thesis advisor) / Spanias, Andreas S (Committee member) / Papandreou-Suppappola, Antonia (Committee member) / Abousleman, Glen P (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2011
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Description
Deep neural networks (DNNs), as a main-stream algorithm for various AI tasks, achieve higher accuracy at the cost of increased computational complexity and model size, posing great challenges to hardware platforms. This dissertation first tackles the design challenges of resistive random-access-memory (RRAM) based in-memory computing (IMC) architectures. A new metric,

Deep neural networks (DNNs), as a main-stream algorithm for various AI tasks, achieve higher accuracy at the cost of increased computational complexity and model size, posing great challenges to hardware platforms. This dissertation first tackles the design challenges of resistive random-access-memory (RRAM) based in-memory computing (IMC) architectures. A new metric, model stability from the loss landscape, is proposed to help shed light on accuracy under variations and model compression and guide a novel variation-aware training (VAT) solution. The proposed method effectively improves post-mapping accuracy of multiple datasets. Next, a hybrid RRAM/SRAM IMC DNN inference accelerator is developed, that integrates an RRAM-based IMC macro, a reconfigurable SRAM-based multiply-accumulate (MAC) macro, and a programmable shifter. The hybrid IMC accelerator fully recovers the inference accuracy post the mapping. Furthermore, this dissertation researches on architectural optimizations for high IMC utilization, low on-chip communication cost, and low energy-delay product (EDP), including on-chip interconnect design, PE array utilization, and tile-to-router mapping and scheduling. The optimal choice of on-chip interconnect results in up to 6x improvement in energy-delay-area product for RRAM IMC architectures. Furthermore, the PE and NoC optimizations show up to 62% improvement in PE utilization, 78% reduction in area, and 78% lower energy-area product for a wide range of modern DNNs. Finally, this dissertation proposes a novel chiplet-based IMC benchmarking simulator, SIAM, and a heterogeneous chiplet IMC architecture to address the limitations of a monolithic DNN accelerator. SIAM utilizes model-based and cycle-accurate simulation to provide a scalable and flexible architecture. SIAM is calibrated against a published silicon result, SIMBA, from Nvidia. The heterogeneous architecture utilizes a custom mapping with a bank of big and little chiplets, and a hybrid network-on-package (NoP) to optimize the utilization, interconnect bandwidth, and energy efficiency. The proposed big-little chiplet-based RRAM IMC architecture significantly improves energy efficiency at lower area, compared to conventional GPUs. In summary, this dissertation comprehensively investigates novel methods that encompass device, circuits, architecture, packaging, and algorithm to design scalable high-performance and energy-efficient IMC architectures.
ContributorsKrishnan, Gokul (Author) / Cao, Yu (Thesis advisor) / Seo, Jae-Sun (Committee member) / Chakrabarti, Chaitali (Committee member) / Ogras, Umit Y. (Committee member) / Arizona State University (Publisher)
Created2022
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Description
Flexible hybrid electronics (FHE) is emerging as a promising solution to combine the benefits of printed electronics and silicon technology. FHE has many high-impact potential areas, such as wearable applications, health monitoring, and soft robotics, due to its physical advantages, which include light weight, low cost and the ability conform

Flexible hybrid electronics (FHE) is emerging as a promising solution to combine the benefits of printed electronics and silicon technology. FHE has many high-impact potential areas, such as wearable applications, health monitoring, and soft robotics, due to its physical advantages, which include light weight, low cost and the ability conform to different shapes. However, physical deformations that can occur in the field lead to significant testing and validation challenges. For example, designers have to ensure that FHE devices continue to meet specs even when the components experience stress due to bending. Hence, physical deformation, which is hard to emulate, has to be part of the test procedures developed for FHE devices. This paper is the first to analyze stress experience at different parts of FHE devices under different bending conditions. Then develop a novel methodology to maximize the test coverage with minimum number of text vectors with the help of a mixed integer linear programming formulation.
ContributorsGao, Hang (Author) / Ozev, Sule (Thesis advisor) / Ogras, Umit Y. (Committee member) / Christen, Jennifer Blain (Committee member) / Arizona State University (Publisher)
Created2018
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Description
Medical ultrasound imaging is widely used today because of it being non-invasive and cost-effective. Flow estimation helps in accurate diagnosis of vascular diseases and adds an important dimension to medical ultrasound imaging. Traditionally flow estimation is done using Doppler-based methods which only estimate velocity in the beam direction. Thus

Medical ultrasound imaging is widely used today because of it being non-invasive and cost-effective. Flow estimation helps in accurate diagnosis of vascular diseases and adds an important dimension to medical ultrasound imaging. Traditionally flow estimation is done using Doppler-based methods which only estimate velocity in the beam direction. Thus when blood vessels are close to being orthogonal to the beam direction, there are large errors in the estimation results. In this dissertation, a low cost blood flow estimation method that does not have the angle dependency of Doppler-based methods, is presented.

First, a velocity estimator based on speckle tracking and synthetic lateral phase is proposed for clutter-free blood flow.

Speckle tracking is based on kernel matching and does not have any angle dependency. While velocity estimation in axial dimension is accurate, lateral velocity estimation is challenging due to reduced resolution and lack of phase information. This work presents a two tiered method which estimates the pixel level movement using sum-of-absolute difference, and then estimates the sub-pixel level using synthetic phase information in the lateral dimension. Such a method achieves highly accurate velocity estimation with reduced complexity compared to a cross correlation based method. The average bias of the proposed estimation method is less than 2% for plug flow and less than 7% for parabolic flow.

Blood is always accompanied by clutter which originates from vessel wall and surrounding tissues. As magnitude of the blood signal is usually 40-60 dB lower than magnitude of the clutter signal, clutter filtering is necessary before blood flow estimation. Clutter filters utilize the high magnitude and low frequency features of clutter signal to effectively remove them from the compound (blood + clutter) signal. Instead of low complexity FIR filter or high complexity SVD-based filters, here a power/subspace iteration based method is proposed for clutter filtering. Excellent clutter filtering performance is achieved for both slow and fast moving clutters with lower complexity compared to SVD-based filters. For instance, use of the proposed method results in the bias being less than 8% and standard deviation being less than 12% for fast moving clutter when the beam-to-flow-angle is $90^o$.

Third, a flow rate estimation method based on kernel power weighting is proposed. As the velocity estimator is a kernel-based method, the estimation accuracy degrades near the vessel boundary. In order to account for kernels that are not fully inside the vessel, fractional weights are given to these kernels based on their signal power. The proposed method achieves excellent flow rate estimation results with less than 8% bias for both slow and fast moving clutters.

The performance of the velocity estimator is also evaluated for challenging models. A 2D version of our two-tiered method is able to accurately estimate velocity vectors in a spinning disk as well as in a carotid bifurcation model, both of which are part of the synthetic aperture vector flow imaging (SA-VFI) challenge of 2018. In fact, the proposed method ranked 3rd in the challenge for testing dataset with carotid bifurcation. The flow estimation method is also evaluated for blood flow in vessels with stenosis. Simulation results show that the proposed method is able to estimate the flow rate with less than 9% bias.
ContributorsWei, Siyuan (Author) / Chakrabarti, Chaitali (Thesis advisor) / Papandreou-Suppappola, Antonia (Committee member) / Ogras, Umit Y. (Committee member) / Wenisch, Thomas F. (Committee member) / Arizona State University (Publisher)
Created2018
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Description
This dissertation proposes and presents two different passive sigma-delta

modulator zoom Analog to Digital Converter (ADC) architectures. The first ADC is fullydifferential, synthesizable zoom-ADC architecture with a passive loop filter for lowfrequency Built in Self-Test (BIST) applications. The detailed ADC architecture and a step

by step process designing the zoom-ADC along with

This dissertation proposes and presents two different passive sigma-delta

modulator zoom Analog to Digital Converter (ADC) architectures. The first ADC is fullydifferential, synthesizable zoom-ADC architecture with a passive loop filter for lowfrequency Built in Self-Test (BIST) applications. The detailed ADC architecture and a step

by step process designing the zoom-ADC along with a synthesis tool that can target various

design specifications are presented. The design flow does not rely on extensive knowledge

of an experienced ADC designer. Two example set of BIST ADCs have been synthesized

with different performance requirements in 65nm CMOS process. The first ADC achieves

90.4dB Signal to Noise Ratio (SNR) in 512µs measurement time and consumes 17µW

power. Another example achieves 78.2dB SNR in 31.25µs measurement time and

consumes 63µW power. The second ADC architecture is a multi-mode, dynamically

zooming passive sigma-delta modulator. The architecture is based on a 5b interpolating

flash ADC as the zooming unit, and a passive discrete time sigma delta modulator as the

fine conversion unit. The proposed ADC provides an Oversampling Ratio (OSR)-

independent, dynamic zooming technique, employing an interpolating zooming front-end.

The modulator covers between 0.1 MHz and 10 MHz signal bandwidth which makes it

suitable for cellular applications including 4G radio systems. By reconfiguring the OSR,

bias current, and component parameters, optimal power consumption can be achieved for

every mode. The ADC is implemented in 0.13 µm CMOS technology and it achieves an

SNDR of 82.2/77.1/74.2/68 dB for 0.1/1.92/5/10MHz bandwidth with 1.3/5.7/9.6/11.9mW

power consumption from a 1.2 V supply.
ContributorsEROL, OSMAN EMIR (Author) / Ozev, Sule (Thesis advisor) / Kitchen, Jennifer (Committee member) / Ogras, Umit Y. (Committee member) / Blain-Christen, Jennifer (Committee member) / Arizona State University (Publisher)
Created2018
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Description
As integrated technologies are scaling down, there is an increasing trend in the

process,voltage and temperature (PVT) variations of highly integrated RF systems.

Accounting for these variations during the design phase requires tremendous amount

of time for prediction of RF performance and optimizing it accordingly. Thus, there

is an increasing gap between the need

As integrated technologies are scaling down, there is an increasing trend in the

process,voltage and temperature (PVT) variations of highly integrated RF systems.

Accounting for these variations during the design phase requires tremendous amount

of time for prediction of RF performance and optimizing it accordingly. Thus, there

is an increasing gap between the need to relax the RF performance requirements at

the design phase for rapid development and the need to provide high performance

and low cost RF circuits that function with PVT variations. No matter how care-

fully designed, RF integrated circuits (ICs) manufactured with advanced technology

nodes necessitate lengthy post-production calibration and test cycles with expensive

RF test instruments. Hence design-for-test (DFT) is proposed for low-cost and fast

measurement of performance parameters during both post-production and in-eld op-

eration. For example, built-in self-test (BIST) is a DFT solution for low-cost on-chip

measurement of RF performance parameters. In this dissertation, three aspects of

automated test and calibration, including DFT mathematical model, BIST hardware

and built-in calibration are covered for RF front-end blocks.

First, the theoretical foundation of a post-production test of RF integrated phased

array antennas is proposed by developing the mathematical model to measure gain

and phase mismatches between antenna elements without any electrical contact. The

proposed technique is fast, cost-efficient and uses near-field measurement of radiated

power from antennas hence, it requires single test setup, it has easy implementation

and it is short in time which makes it viable for industrialized high volume integrated

IC production test.

Second, a BIST model intended for the characterization of I/Q offset, gain and

phase mismatch of IQ transmitters without relying on external equipment is intro-

duced. The proposed BIST method is based on on-chip amplitude measurement as

in prior works however,here the variations in the BIST circuit do not affect the target

parameter estimation accuracy since measurements are designed to be relative. The

BIST circuit is implemented in 130nm technology and can be used for post-production

and in-field calibration.

Third, a programmable low noise amplifier (LNA) is proposed which is adaptable

to different application scenarios depending on the specification requirements. Its

performance is optimized with regards to required specifications e.g. distance, power

consumption, BER, data rate, etc.The statistical modeling is used to capture the

correlations among measured performance parameters and calibration modes for fast

adaptation. Machine learning technique is used to capture these non-linear correlations and build the probability distribution of a target parameter based on measurement results of the correlated parameters. The proposed concept is demonstrated by

embedding built-in tuning knobs in LNA design in 130nm technology. The tuning

knobs are carefully designed to provide independent combinations of important per-

formance parameters such as gain and linearity. Minimum number of switches are

used to provide the desired tuning range without a need for an external analog input.
ContributorsShafiee, Maryam (Author) / Ozev, Sule (Thesis advisor) / Diaz, Rodolfo (Committee member) / Ogras, Umit Y. (Committee member) / Bakkaloglu, Bertan (Committee member) / Arizona State University (Publisher)
Created2018