Engineering Commons^™

Quality Of Experience Aware Spectrum Efficiency And Energy Efficiency Over Wireless Heterogeneous Networks, Yiran Xu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Propelled by the explosive increases in mobile data traffic volume, existing wireless technologies are stretched to their capacity limits. There is a tremendous need for an expansion in system capacity and an improvement on energy efficiency. In addition, wireless network will support more and more multimedia services and applications, in which user experience has been always an important factor in evaluating the overall network performance. In order to keep pace with this explosion of data traffic and to meet the emerging quality of experience needs, wireless heterogeneous networks have been introduced as a promising network architecture evolution of the traditional …

Evapotranspiration Estimation: A Study Of Methods In The Western United States, Clayton S. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Theoretical water use of well-watered vegetation in the western United States was investigated by comparing a gridded dataset developed from satellite and ground instruments to weather stations representative of irrigated agricultural conditions. Since wetter environments are cooler and therefore subject to lower levels of evaporation than the same scenario with warmer temperatures, models derived from dryland and often populated areas overestimate potential plant needs in semi-arid or arid conditions. Evaluation of the model revealed an acceptable fit for air temperatures and solar radiation but with less confidence in humidity and wind speeds. Ultimately, the last two parameters were minor components …

Investigating The Effect Of Carbon Nanotube Functionalization In A Polydimethylsiloxane Composite Through Use Of A Stepped Bar Apparatus, Matthew I. Ralphs

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thermal interface materials (TIMs) are used in transporting heat away from a circuit or electronic module. Composite materials are a popular research area for TIMs because they allow the desired properties to be joined in a composite to take advantage of the best properties from all the constituents involved. The composite selected for this study uses carbon nanotubes (CNT) as the filler and an elastomeric polymer for the matrix, specifically a multiwalled carbon nanotube (MWCNT) / polydimethylsiloxane (PDMS) composite. This study looks at chemical modification (functionalization) of the CNTin an effort to produce a better bond between the CNT and …

An Arithmetic-Based Deterministic Centroid Initialization Method For The K-Means Clustering Algorithm, Matthew Michael Mayo

Theses and Dissertations

One of the greatest challenges in k-means clustering is positioning the initial cluster centers, or centroids, as close to optimal as possible, and doing so in an amount of time deemed reasonable. Traditional fc-means utilizes a randomization process for initializing these centroids, and poor initialization can lead to increased numbers of required clustering iterations to reach convergence, and a greater overall runtime. This research proposes a simple, arithmetic-based deterministic centroid initialization method which is much faster than randomized initialization. Preliminary experiments suggest that this collection of methods, referred to herein as the sharding centroid initialization algorithm family, often outperforms random …

An Exploration Of Rule Clustering In Cellular Automata Rule Spaces, Jordon Huffman

Theses and Dissertations

The study of complex systems examines the global behavior of a system and how the individual parts of the system affect that behavior [1]. The study of complex systems spans across many fields of science like biology, physics, engineering, and computer science. One area of complex systems that has not been fully explored is cellular automata. Since its discovery by John von Neumann, there have been no consistent ways of categorizing similarities between cellular automata rules or collecting similar rules for observation. This thesis introduces an approach to identifying clusters of similar rules and extracting rules from that cluster. Several …

Simultaneous Optimization And Sampling Of Agent Trajectories Over A Network, Hala Mostafa, Akshat Kumar, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We study the problem of optimizing the trajectories of agents moving over a network given their preferences over which nodes to visit subject to operational constraints on the network. In our running example, a theme park manager optimizes which attractions to include in a day-pass to maximize the pass’s appeal to visitors while keeping operational costs within budget. The first challenge in this combinatorial optimization problem is that it involves quantities (expected visit frequencies of each attraction) that cannot be expressed analytically, for which we use the Sample Average Approximation. The second challenge is that while sampling is typically done …

Approximate Inference Using Dc Programming For Collective Graphical Models, Duc Thien Nguyen, Akshat Kumar, Hoong Chuin Lau, Daniel Sheldon

Research Collection School Of Computing and Information Systems

Collective graphical models (CGMs) provide a framework for reasoning about a population of independent and identically distributed individuals when only noisy and aggregate observations are given. Previous approaches for inference in CGMs work on a junction-tree representation, thereby highly limiting their scalability. To remedy this, we show how the Bethe entropy approximation naturally arises for the inference problem in CGMs. We reformulate the resulting optimization problem as a difference-of-convex functions program that can capture different types of CGM noise models. Using the concave-convex procedure, we then develop a scalable message-passing algorithm. Empirically, our approach is highly scalable and accurate for …

Reinforcement Learning Framework For Modeling Spatial Sequential Decisions Under Uncertainty: (Extended Abstract), Truc Viet Le, Siyuan Liu, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We consider the problem of trajectory prediction, where a trajectory is an ordered sequence of location visits and corresponding timestamps. The problem arises when an agent makes sequential decisions to visit a set of spatial locations of interest. Each location bears a stochastic utility and the agent has a limited budget to spend. Given the agent's observed partial trajectory, our goal is to predict the remaining trajectory. We propose a solution framework to the problem considering both the uncertainty of utility and the budget constraint. We use reinforcement learning (RL) to model the underlying decision processes and inverse RL to …

Robust Influence Maximization, Meghna Lowalekar, Pradeep Varakantham, Akshat Kumar

Research Collection School Of Computing and Information Systems

Influence Maximization is the problem of finding a fixed size set of nodes, which will maximize the expected number of influenced nodes in a social network. The number of influenced nodes is dependent on the influence strength of edges that can be very noisy. The noise in the influence strengths can be modeled using a random noise or adversarial noise model. It has been shown that all random processes that independently affect edges of the graph can be absorbed into the activation probabilities themselves and hence random noise can be captured within the independent cascade model. On the other hand, …

Efspredictor: Predicting Configuration Bugs With Ensemble Feature Selection, Bowen Xu, David Lo, Xin Xia, Ashish Sureka, Shanping Li

Research Collection School Of Computing and Information Systems

The configuration of a system determines the system behavior and wrong configuration settings can adversely impact system's availability, performance, and correctness. We refer to these wrong configuration settings as configuration bugs. The importance of configuration bugs has prompted many researchers to study it, and past studies can be grouped into three categories: detection, localization, and fixing of configuration bugs. In the work, we focus on the detection of configuration bugs, in particular, we follow the line-of-work that tries to predict if a bug report is caused by a wrong configuration setting. Automatically prediction of whether a bug is a configuration …

Experimental, Numerical, And Analytical Slosh Dynamics Of Water And Liquid Nitrogen In A Spherical Tank, Jedediah Morse Storey

Theses and Dissertations

Understanding, predicting, and controlling fluid slosh dynamics is critical to safety and improving performance of space missions when a significant percentage of the spacecraft’s mass is a liquid. Computational fluid dynamics simulations can be used to predict the dynamics of slosh, but these programs require extensive validation. Many experimental and numerical studies of water slosh have been conducted. However, slosh data for cryogenic liquids is lacking. Water and cryogenic liquid nitrogen are used in various ground-based tests with a spherical tank to characterize damping, slosh mode frequencies, and slosh forces. A single ring baffle is installed in the tank for …

A Method To Enhance The Heat Transfer Mechanism In Metal Particle Porous Beds With Applicability To Paramagnetic Materials For Hydrogen Storage, Shahin Shafiee

Theses and Dissertations

This research introduces a heat transfer enhancement method for porous beds of either ferromagnetic and paramagnetic materials. Throughout this work, it is shown that applying magnetic fields, not only enhances the heat transfer rate in particle beds but also improves hydrogenation properties of lanthanum nickel. The first section of the work is focused on heat transfer in iron oxide beds under magnetism. This stage studies effect of different magnetic field configurations and intensities on conduction improvement. The second phase of the work, studies the effect of utilizing magnetic fields on hydriding properties of a selected metal hydride. Experimentation has proven …

Microalgae Cell Quantification Using Electrical Parameters, Leena Osama Fahmi Saqer

Theses

Electrical properties of living cells have been proven to play a significant role in understanding and characterizing the different biological activities of the cell. The objective of this work is to develop an electrical based technique for determining and estimating the number of microalgae cells in a suspension without the need for any sample treatments or pre-processing.

The proposed technique is based on the direct use of electrical capacitive model. The basic premise behind this idea is the electrical polarization of microalgae particles that get charged due to the application of an electric field. This wouldn’t cause any distortion or …

Behavior Of Expansive Concrete-Filled Steel Tubular (Ecfst) Columns Under Axial Loadings, Abdulaziz Lazkani

Theses

Concrete-filled steel tubes (CFST) have been introduced in high-rise buildings in order to expedite construction and increase the confinement of concrete by the steel tube, and hence increase the capacity of the column cross-section. More recently, expansive additives (EAs) that counteract the shrinkage of concrete have been used in CFST to improve the bond between the concrete and steel tube. Although changing the confinement level exerted by the steel tube on concrete will have an impact on the behavior of CFSTs, little information is available regarding the influence of EAs on the mechanical characteristics of expansive concrete-filled steel tubular (ECFST) …

Recycling Ceramic Waste Powder And Its Usage As An Alternative Ingredient In Concrete, Dima Mamoun Kanaan

Theses

Green environment is a challenging concern to accomplish in today’s world. This could be accomplished through an effective and beneficial recycling system through reusing solid waste materials. The study and exploration of alternative ingredients for concrete-making industry started more than five decades ago. Concrete that contains solid waste is referred to as “Green” concrete. Ceramic tiles are widely used in most structures; its production creates waste powder. Using ceramic waste powder (CWP) as an ingredient to partially replace cement in concrete will have a positive and progressive environmental impact in addition will help reserve natural resources. In this study, CWP …

Carbon Dioxide Capture By Steel-Making Residues In A Fluidized Bed Reacto, Suhaib Mohammad Hameedi

Theses

Global warming is one of the most challenging problems facing societies these days, and it is known to be caused by the increasing emissions of Green House Gases (GHG's), mainly CO₂, from various human activities. To solve such a problem, or at least minimize its effects, several actions have been considered. One of these actions is carbon capture, which has many different options and techniques. This research focuses on the capture of CO₂ through reactions with steel-making residues, an alkaline solid by-product of the steel-making process. The aim is to sequester CO₂ and form carbonates, which …

Bbq Grill Temperature Uniformity Study, Monty Dodge Jr, Samuel Melo

Mechanical Engineering

Bull Outdoor Products, Incorporated, a barbeque grill and outdoor kitchen manufacturer, sponsored this project with the intent of improving the temperature uniformity across the surface of their barbecue grills. For this project, the Cal Poly team of mechanical engineering students, Monty Dodge Jr. and Samuel Melo, used the Brahma grill head model with setups for both natural gas and propane. In order to determine exactly what the uniformity across the grill surface was, the student team designed a testing apparatus which would measure a grid of temperature locations one inch apart spanning an area 16 by 36 inches. Developing a …

Material Evaluation Of A Lightweight, Automated Canned Pet Food Dispenser, Kathryn Marie Carr

Honors Capstones

No abstract provided.

Ultra Short Mr Relaxometry And Histological Image Processing For Validation Of Diffusion Mri, Amin Nazaran

Theses and Dissertations

Magnetic Resonance Imaging (MRI) is an imaging modality that acquires an image with little to no damage to the tissue. MRI does not introduce foreign particles or high energy radiation into the body, making it one of the least invasive medical imaging modalities. MRI can achieve excellent soft tissue contrast and is therefore useful for diagnosis of a wide variety of diseases. While there are a wide variety of available techniques for generating contrast in MRI, there are still many open areas for research. For example, many tissues in the human body exhibit such rapid signal decay that they are …

Xhab Microgravity Food Growth Chamber, Nathan I. Stacey

Undergraduate Honors Capstone Projects

NASA and other organizations are preparing to send humans deeper into space, including a NASA manned mission to Mars in the 2030s, in order to learn more about our universe and the origin of life and to ensure the survival of the human race. Long journeys in space require efficient, dependable, and sustainable methods to provide for astronauts' metabolic needs such as oxygen, water, and food. In order for microgravity plant growth chambers to become a viable solution, several challenges encountered by past growth chambers must be resolved.

One problem with existing space food growth chambers is hypoxia, or lack …

Analysis Of Large Scale Pv Systems With Energy Storage To A Utility Grid, Joseph M. Lavalliere

All Theses

With electric distribution network operators experiencing an exponential increase in distributed energy resource connections to the power grid, operational challenges arise attributable to the traditional methods of building distribution feeders. Photovoltaic (PV) solar systems are the major contributor due to recent technological advancements. Though this renewable energy resource is beneficial to human society, unfavorable electrical conditions can arise from the inherit variability of solar energy. Extreme variability of power injection can force excessive operations of voltage regulation equipment and potentially degrade customer voltage quality. If managed and controlled properly, battery energy storage systems installed on a distribution feeder have the …

Fabrication And Characterization Of An Extracellular Matrix Hydrogel For Aortic Valve Applications, Brady Culbreth

All Theses

With an estimated 5 million people suffering from valve disease in the United, valve disease is currently the leading cause of cardiovascular disease. Each year, between 80,000 and 85,000 aortic valve replacements are performed in order to treat the stenotic heart valves. Despite this being a worldwide epidemic, the current valve replacement options that are on the market have distinct limitations. Furthermore, a viable alternative does not exist for the patients that are not candidates for the current treatment methods. Our proposed solution to this epidemic is to create a highly viable injectable scaffold that would allow for the minimally …

Heart Beat Monitor, Ivan Mireles, Sneha Pottian

Mechatronics Final Projects

This project is used to detect the number of heartbeats per minute from the fingertip of a patient. It is also meant to display how a heart beats based off the signal it picks up from the pulse through an analog counter. Once the user turns on the power button, they will be instructed to place their finger on the sensing tip (ref. To Fig. 1). Once the user has placed their finger on the pulse sensor, the system will require that the start button be pressed to start counting up the heart beats. As the heart beats are sensed …

Campus Cruiser, Mikey Robison, Todd Edwards

Mechatronics Final Projects

Throughout the course of this semester we designed and built an electronic control unit for a gas-powered go-kart. The goal for our project was to design and install an electronic control unit that would incorporate: an electronic throttle, an electronic kill switch, two tachometers – one to measure vehicle speed and one to measure engine shaft speed – with LCDs to display the speed and RPM values. The control unit, displays, and controls were mounted on steering wheel and dashboard housings that included two LEDs to display the status of the engine kill switch and a speaker which beeps to …

Understanding Pyrotechnic Shock Dynamics And Response Attenuation Over Distance, Richard J. Ott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Component requirements govern design and production in the aerospace industry. One such potential requirement for a component is the survival and continued function upon exposure to shock environments. A shock event is a high amplitude, short duration traveling wave that induces large loads on components in its path that can cause degradation of electronic components, cracks and fractures in brittle materials, local plastic deformation, and materials to experience accelerated fatigue life. In defining these environments for new structures, industry experts rely mainly on empirical data. Measurements from similar structures are scaled and enveloped to create a predicted bounding case. This …

Pedicle Lengthening Spacer, David S. Wood

Undergraduate Honors Capstone Projects

In the lumbar region of the spine, the spinal cord travels through a small hole in your vertebrae called the spinal canal. There is a medical condition where the spinal canal becomes restricted. This condition is called stenosis. There are several reasons for this pinching of the spinal column. These include the growth of bone spurs, the accumulation of ligaments in the canal, or a genetic trait. When these occur in the lower five vertebrae (the lumbar region), it is called lumbar stenosis. The symptoms of Lumbar Stenosis are shooting pain through the legs, especially during activity, and feelings of …

Microwire Regenerative Peripheral Nerve Interfaces With Wireless Recording And Stimulation Capabilities, Ali Ajam

Theses and Dissertations

A scalable microwire peripheral nerve interface was developed, which interacted with regenerated peripheral nerves in microchannel scaffolds. Neural interface technologies are envisioned to facilitate direct connections between the nervous system and external technologies such as limb prosthetics or data acquisition systems for further processing. Presented here is an animal study using a handcrafted microwire regenerative peripheral nerve interface, a novel neural interface device for communicating with peripheral nerves. The neural interface studies using animal models are crucial in the evaluation of efficacy and safety of implantable medical devices before their use in clinical studies.16-electrode microwire microchannel scaffolds were developed for …

Predicting The Market Share Of A New Airport In Multi-Airport Cities: The Case Of Lagos, Samson Oladele Fatokun

Doctoral Dissertations and Master's Theses

The primary objective of the study was to develop an empirical model that combines the contingent valuation method (CVM) with the isochrone analysis to predict the market shares of new airports in multi-airport cities and to apply the model to the case of Lekki International Airport (LIA), the proposed second airport in Lagos, Nigeria. In addition to predicting the market share that LIA could attain, the study also identified and analyzed the catchment areas as well as the willingness to pay (WTP) of would-be LIA passengers. Furthermore, the research identified the determinants of airport choice in the Nigerian market. The …

Safte-Vat Functionality Effects On Flight Instructors' Situation Awareness And Instrument Student Pilots' Performance During Ftd Training, Rafael E. Abreu Vega

Doctoral Dissertations and Master's Theses

SAFTE-VAT is a virtual air traffic control systems that adds the capability to integrate automated air traffic control functionality and generate semiautonomous and autonomous air traffic to the Frasca 172S level 6 plus FTD to improve behavioral fidelity and to facilitate flight instructors the capacity to focus more on instructing student pilots instead of role-playing ATC duties. While SAFTE-VAT may offer a more realistic ATC interaction experience onboard the FTD that may result in a positive transfer of training increase, the effects on flight instructors’ situation awareness and overall student pilot performance are uncertain. In this small study, flight instructors …

An Experimental Study Of Momentum-Driven Unsteady Jets, Sravan Kumar Artham

Doctoral Dissertations and Master's Theses

Jets are seen commonly in nature and engineering and can be broadly classified into steady and unsteady jets. The study of unsteady jets has received little attention when compared to its steady counterpart. A type of unsteady jet is the turbulent puff which is a momentum driven jet in which fluid is ejected from a jet orifice intermittently. Common examples of turbulent puff like jets are coughs and volcanoes. The studies on momentum driven unsteady jets have primarily focused on single ejection events (single puffs) where an instantaneous supply of momentum drives the source fluid downstream of a nozzle. This …