Engineering Commons^™

Automating Intensity Modulated Radiation Therapy Treatment Planning By Using Hierarchical Optimization, Paras Babu Tiwari

McKelvey School of Engineering Theses & Dissertations

The intensity modulated radiation therapy (IMRT) optimizes the beam’s intensity to deliver the prescribed dose to the target while minimizing the radiation exposure to normal structures. The IMRT optimization is a complex optimization problem because of the multiple conflicting objectives in it. Due to the complexity of the optimization, the IMRT treatment planning is still a trial and error process. Hierarchical optimization was proposed to automate the treatment planning process, but its potential has not been demonstrated in a clinical setting. Moreover, hierarchical optimization is slower than the traditional optimization. The dissertation studied a sampling algorithm to reduce the hierarchical …

Cfd Simulation And Shape Optimization Of Supersonic Ejectors For Refrigeration And Desalination Applications, Liju Su

McKelvey School of Engineering Theses & Dissertations

The aim of this thesis is to investigate the detailed flow field inside the supersonic ejector using numerical methods and to optimize the ejector’s mixing chamber wall shape to obtain a maximum entrainment ratio (ER) in order to obtain the highest possible efficiency that can be attained by the ejector. A steam ejector applied in the cooling industry is first studied to determine the most accurate turbulence model for its supersonic jet flow field simulation with mixing with the entrained steam in the mixing chamber. A commercial Computational Fluid Dynamics (CFD) package FLUENT 14.5 along with the meshing tool ICEM …

Optimization Of Blalock-Taussig Shunt And Anastomotic Geometry For Vascular Access Fistula Using A Genetic Algorithm, Guangyu Bao

McKelvey School of Engineering Theses & Dissertations

Blalock-Taussig (BT) shunts are used for defects that affect the flow of blood from the right ventricle, through the pulmonary artery, and to the lungs. Arteriovenous (AV) fistula is one type of vascular access which is a surgically created vein used to remove and return blood during hemodialysis. Plastic grafts used in the above two reconstructions may result in areas of non-physiologic flow in the grafts leading to risk of stenosis (blocked area) and thrombosis, which is the single major cause for access morbidity. The focus of this thesis is to study BT shunts and anastomoses models using Computational Fluid …

Integration Of Alignment And Phylogeny In The Whole-Genome Era, Hongtao Sun

McKelvey School of Engineering Theses & Dissertations

With the development of new sequencing techniques, whole genomes of many species have become available. This huge amount of data gives rise to new opportunities and challenges. These new sequences provide valuable information on relationships among species, e.g. genome recombination and conservation. One of the principal ways to investigate such information is multiple sequence alignment (MSA). Currently, there is large amount of MSA data on the internet, such as the UCSC genome database, but how to effectively use this information to solve classical and new problems is still an area lacking of exploration. In this thesis, we explored how to …

Application-Specific Memory Subsystems, Joseph George Wingbermuehle

McKelvey School of Engineering Theses & Dissertations

The disparity in performance between processors and main memories has

led computer architects to incorporate large cache hierarchies in

modern computers. These cache hierarchies are designed to be

general-purpose in that they strive to provide the best possible

performance across a wide range of applications. However, such a memory

subsystem does not necessarily provide the best possible performance for

a particular application.

Although general-purpose memory subsystems are desirable when the

work-load is unknown and the memory subsystem must remain fixed,

when this is not the case a custom memory subsystem may be beneficial.

For example, in an application-specific integrated circuit …