Matching Items (7)
Filtering by

Clear all filters

152200-Thumbnail Image.png
Description
Magnetic Resonance Imaging using spiral trajectories has many advantages in speed, efficiency in data-acquistion and robustness to motion and flow related artifacts. The increase in sampling speed, however, requires high performance of the gradient system. Hardware inaccuracies from system delays and eddy currents can cause spatial and temporal distortions in

Magnetic Resonance Imaging using spiral trajectories has many advantages in speed, efficiency in data-acquistion and robustness to motion and flow related artifacts. The increase in sampling speed, however, requires high performance of the gradient system. Hardware inaccuracies from system delays and eddy currents can cause spatial and temporal distortions in the encoding gradient waveforms. This causes sampling discrepancies between the actual and the ideal k-space trajectory. Reconstruction assuming an ideal trajectory can result in shading and blurring artifacts in spiral images. Current methods to estimate such hardware errors require many modifications to the pulse sequence, phantom measurements or specialized hardware. This work presents a new method to estimate time-varying system delays for spiral-based trajectories. It requires a minor modification of a conventional stack-of-spirals sequence and analyzes data collected on three orthogonal cylinders. The method is fast, robust to off-resonance effects, requires no phantom measurements or specialized hardware and estimate variable system delays for the three gradient channels over the data-sampling period. The initial results are presented for acquired phantom and in-vivo data, which show a substantial reduction in the artifacts and improvement in the image quality.
ContributorsBhavsar, Payal (Author) / Pipe, James G (Thesis advisor) / Frakes, David (Committee member) / Kodibagkar, Vikram (Committee member) / Arizona State University (Publisher)
Created2013
155837-Thumbnail Image.png
Description
With the advent of GPGPU, many applications are being accelerated by using CUDA programing paradigm. We are able to achieve around 10x -100x speedups by simply porting the application on to the GPU and running the parallel chunk of code on its multi cored SIMT (Single instruction multiple thread) architecture.

With the advent of GPGPU, many applications are being accelerated by using CUDA programing paradigm. We are able to achieve around 10x -100x speedups by simply porting the application on to the GPU and running the parallel chunk of code on its multi cored SIMT (Single instruction multiple thread) architecture. But for optimal performance it is necessary to make sure that all the GPU resources are efficiently used, and the latencies in the application are minimized. For this, it is essential to monitor the Hardware usage of the algorithm and thus diagnose the compute and memory bottlenecks in the implementation. In the following thesis, we will be analyzing the mapping of CUDA implementation of BLIINDS-II algorithm on the underlying GPU hardware, and come up with a Kepler architecture specific solution of using shuffle instruction via CUB library to tackle the two major bottlenecks in the algorithm. Experiments were conducted to convey the advantage of using shuffle instru3ction in algorithm over only using shared memory as a buffer to global memory. With the new implementation of BLIINDS-II algorithm using CUB library, a speedup of around 13.7% was achieved.
ContributorsWadekar, Ameya (Author) / Sohoni, Sohum (Thesis advisor) / Aukes, Daniel (Committee member) / Redkar, Sangram (Committee member) / Arizona State University (Publisher)
Created2017
164468-Thumbnail Image.png
ContributorsKwan, Anson (Author) / Aukes, Daniel (Thesis director) / Marvi, Hamidreza (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2022-05
164469-Thumbnail Image.jpg
ContributorsKwan, Anson (Author) / Aukes, Daniel (Thesis director) / Marvi, Hamidreza (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2022-05
164470-Thumbnail Image.jpg
ContributorsKwan, Anson (Author) / Aukes, Daniel (Thesis director) / Marvi, Hamidreza (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2022-05
164471-Thumbnail Image.jpg
ContributorsKwan, Anson (Author) / Aukes, Daniel (Thesis director) / Marvi, Hamidreza (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2022-05
Description

In this paper, we discuss the methods and requirements to simulate a soft bodied beam using traditional rigid body kinematics to produce motion inspired by eels. Eels produce a form of undulatory locomotion called anguilliform locomotion that propagates waves throughout the entire body. The system that we are analyzing is

In this paper, we discuss the methods and requirements to simulate a soft bodied beam using traditional rigid body kinematics to produce motion inspired by eels. Eels produce a form of undulatory locomotion called anguilliform locomotion that propagates waves throughout the entire body. The system that we are analyzing is a flexible 3D printed beam being actively driven by a servo motor. Using the simulation, we also analyze different parameters for these spines to maximize the linear speed of the system.

ContributorsKwan, Anson (Author) / Aukes, Daniel (Thesis director) / Marvi, Hamidreza (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2022-05