2,442 Works

Multivariate Functional Data Analysis and Visualization

Zhuo Qu
As a branch of statistics, functional data analysis (FDA) studies observations regarded as curves, surfaces, or other objects evolving over a continuum. Although one has seen a flourishing of methods and theories on FDA, two issues are observed. Firstly, the functional data are sampled from common time grids; secondly, methods developed only for univariate functional data are challenging to be applied to multivariate functional data. After exploring model-based fitting for regularly observed multivariate functional data,...

Comprehensive Kinetic Study of Oxidative Coupling of Methane (OCM) over La2O3-based catalysts

Haoyi Wang
Oxidative coupling of methane (OCM) represents a potentially viable method to convert methane directly into more desirable products such as ethane, and ethylene. In this dissertation, a comprehensive kinetic study of oxidative coupling of methane was performed over La2O3-based catalysts. An accurate and reliable gas-phase model is critical for the entire mechanism. The gas-phase kinetics was first studied using a jet-stirred reactor without catalyst. Both experiments and simulations were conducted under various operating conditions using...

Multivariate Functional Data Analysis and Visualization

Zhuo Qu
As a branch of statistics, functional data analysis (FDA) studies observations regarded as curves, surfaces, or other objects evolving over a continuum. Although one has seen a flourishing of methods and theories on FDA, two issues are observed. Firstly, the functional data are sampled from common time grids; secondly, methods developed only for univariate functional data are challenging to be applied to multivariate functional data. After exploring model-based fitting for regularly observed multivariate functional data,...

Pulse Shaped Waveform Characterization using the Schrödinger Operator’s Spectrum

Peihao Li
Pulse-shaped signals require a tool that can accurately analyse and identify the peak characteristics in the spectrum. One recently developed tool available to analyse non-stationary pulse-shaped waveforms with a suitable peak reconstruction is semiclassical signal analysis (SCSA). SCSA is a signal representation method that decomposes a real positive signal y(t) into a set of squared eigenfunctions through the discrete spectrum of the Schr¨odinger operator. In this study, we apply SCSA in two directions. First, we...

Pulse Shaped Waveform Characterization using the Schrödinger Operator’s Spectrum

Peihao Li
Pulse-shaped signals require a tool that can accurately analyse and identify the peak characteristics in the spectrum. One recently developed tool available to analyse non-stationary pulse-shaped waveforms with a suitable peak reconstruction is semiclassical signal analysis (SCSA). SCSA is a signal representation method that decomposes a real positive signal y(t) into a set of squared eigenfunctions through the discrete spectrum of the Schr¨odinger operator. In this study, we apply SCSA in two directions. First, we...

Flexible Extremal Dependence Models for Multivariate and Spatial Extremes

Zhongwei Zhang
Classical models for multivariate or spatial extremes are mainly based upon the asymptotically justified max-stable or generalized Pareto processes. These models are suitable when asymptotic dependence is present. However, recent environmental data applications suggest that asymptotic independence is equally important. Therefore, development of flexible subasymptotic models is in pressing need. This dissertation consists of four major contributions to subasymptotic modeling of multivariate and spatial extremes. Firstly, the dissertation proposes a new spatial copula model for...

New tools for the description of intra/inter laminar coupling in laminates: experimental evidence and modeling approaches

Ping Hu
Carbon fiber reinforced polymers (CFRP) are widely used in advanced industry, like aerospace, modern sports, and automobile. Compared to traditional metals, CFRP laminates have a higher strength to weight ratio and better corrosion resistance. Because of the heterogeneous and anisotropic behavior of CFRP laminates, their damage mechanisms include fiber/matrix debonding, diffuse matrix damage, matrix cracking, fiber breakage, and delamination. These damage mechanisms develop in different length scales and are deeply coupled with each other, especially...

Flexible Extremal Dependence Models for Multivariate and Spatial Extremes

Zhongwei Zhang
Classical models for multivariate or spatial extremes are mainly based upon the asymptotically justified max-stable or generalized Pareto processes. These models are suitable when asymptotic dependence is present. However, recent environmental data applications suggest that asymptotic independence is equally important. Therefore, development of flexible subasymptotic models is in pressing need. This dissertation consists of four major contributions to subasymptotic modeling of multivariate and spatial extremes. Firstly, the dissertation proposes a new spatial copula model for...

Flexible Extremal Dependence Models for Multivariate and Spatial Extremes

Zhongwei Zhang
Classical models for multivariate or spatial extremes are mainly based upon the asymptotically justified max-stable or generalized Pareto processes. These models are suitable when asymptotic dependence is present. However, recent environmental data applications suggest that asymptotic independence is equally important. Therefore, development of flexible subasymptotic models is in pressing need. This dissertation consists of four major contributions to subasymptotic modeling of multivariate and spatial extremes. Firstly, the dissertation proposes a new spatial copula model for...

Comprehensive Kinetic Study of Oxidative Coupling of Methane (OCM) over La2O3-based catalysts

Haoyi Wang
Oxidative coupling of methane (OCM) represents a potentially viable method to convert methane directly into more desirable products such as ethane, and ethylene. In this dissertation, a comprehensive kinetic study of oxidative coupling of methane was performed over La2O3-based catalysts. An accurate and reliable gas-phase model is critical for the entire mechanism. The gas-phase kinetics was first studied using a jet-stirred reactor without catalyst. Both experiments and simulations were conducted under various operating conditions using...

Multivariate Functional Data Analysis and Visualization

Zhuo Qu
As a branch of statistics, functional data analysis (FDA) studies observations regarded as curves, surfaces, or other objects evolving over a continuum. Although one has seen a flourishing of methods and theories on FDA, two issues are observed. Firstly, the functional data are sampled from common time grids; secondly, methods developed only for univariate functional data are challenging to be applied to multivariate functional data. After exploring model-based fitting for regularly observed multivariate functional data,...

Pulse Shaped Waveform Characterization using the Schrödinger Operator’s Spectrum

Peihao Li
Pulse-shaped signals require a tool that can accurately analyse and identify the peak characteristics in the spectrum. One recently developed tool available to analyse non-stationary pulse-shaped waveforms with a suitable peak reconstruction is semiclassical signal analysis (SCSA). SCSA is a signal representation method that decomposes a real positive signal y(t) into a set of squared eigenfunctions through the discrete spectrum of the Schr¨odinger operator. In this study, we apply SCSA in two directions. First, we...

Numerical Approximations of Mean-Field-Games

Serikbolsyn Duisembay
In this thesis, we present three projects. First, we investigate the numerical approximation of Hamilton-Jacobi equations with the Caputo time-fractional derivative. We introduce an explicit in time discretization of the Caputo derivative and a finite-difference scheme for the approximation of the Hamiltonian. We show that the approximation scheme so obtained is stable under an appropriate condition on the discretization parameters and converges to the unique viscosity solution of the Hamilton-Jacobi equation. Also, we study the...

Perovskite/Silicon tandem solar cells: the trilogy of properties, performance, and stability

Rawan S. Jalmood
With the rapid increase in energy demand and the rise of CO2 levels due to traditional energy production from fossil fuels, it is critical to the transition to a sustainable and renewable energy sources. Recently, photovoltaic technology has been raised as a promising alternative to fossil fuel energy production. Solar cells, predominately crystalline silicon technology, are currently 3.6% of electricity production. To maintain this progress, coupling the perovskite and silicon in tandem devices has enormous...

Simulation and Calibration of Uncertain Space Fractional Diffusion Equations

Hasnaa H. Alzahrani
Fractional diffusion equations have played an increasingly important role in ex- plaining long-range interactions, nonlocal dynamics and anomalous diffusion, pro- viding effective means of describing the memory and hereditary properties of such processes. This dissertation explores the uncertainty propagation in space fractional diffusion equations in one and multiple dimensions with variable diffusivity and order parameters. This is achieved by:(i) deploying accurate numerical schemes of the forward problem, and (ii) employing uncertainty quantifications tools that accelerate...

Evaluating the regulation of signaling pathways downstream of CD44 antibody treatment in AML

Arwa Alghuneim
Acute myeloid leukemia (AML) is a subset of leukemia that is characterized by the clonal expansion of cytogenetically and molecularly abnormal myeloid blasts. These blasts are highly proliferative accumulating in bone marrow and blood which leads to severe infections, anemia, and bone marrow failure. The poor prognosis of AML patients caused by the low tolerance to intensive chemotherapy has encouraged the pursuit of alternative therapeutic approaches. Differentiation therapy which involves the use of agents that...

Interactive Exploration of Objective Vortex Structures in Unsteady Flow using Observer Fields

Ghofran H. Shaker
Successful characterization of vortex structures in unsteady flow fields depend crucially upon an adequate choice of a reference frame. Vortex detection approaches in flow visualization aspire to be objective, i.e., invariant under time-dependent rotations and translations of the input reference frame. However, objectivity by itself does not guarantee good results as different specific approaches lead to different results. Moreover, recent more generic approaches to objectivity still require parameters to be specified beforehand which can significantly...

Variations in reef-associated fish communities in response to different benthic states in the east central Red Sea

George Short
Coral reefs are priority habitats which are vulnerable to natural and anthropogenic disturbances. These can cause phase shifts from coral habitat to degraded algal-dominated states – and consequent changes in the distribution, abundance and activity of associated fish species. In the eastern Red Sea, human-induced reef degradation is likely to increase with planned development of the Saudi Arabian coast and the changing climate. The present study therefore investigates the ecological effects of coral-algal phase shifts...

Study of ultraviolet AlGaN nanowires light-emitting diodes

Davide Priante
Ultraviolet (UV) group III-Nitride-based light emitters have been used in various applications such as water purification, medicine, lighting and chemical detection. Despite attractive properties such as bandgap tunability in the whole UV range (UV-C to UV-A), high chemical stability and relative low cost, the low quantum efficiency hamper the full utilization. In fact, external quantum efficiencies of UV devices are below 10 % for emission wavelength shorter than 350 nm. This thesis aims to show...

Skeletonization of Data for Seismic Inversion, Seismic Imaging and GPS Marker Detection

Shihang Feng
This thesis develops four skeletonization methods for seismic inversion, seismic imaging, and GPS marker detection to improve both their computational efficiency and accuracy. The first two improve the accuracy of the final inverted images by novel skeletonized inversion methods. The third one improves the quality of seismic imaging by employing skeletonized preconditional operators. The fourth one uses skeletonized data for machine learning (ML) identification of GPS markers in drone photos. Three papers are published in...

Optimizing a Selective Whole Genome Amplification (SWGA) Strategy for Clinical Malaria Infections

Mariah Alawi
Plasmodium is a genus well known for causing malaria, a life-threatening infection for many people where malaria is endemic. The blood-borne disease is transmitted by the female Anopheles mosquito. Till date, eight parasite species have been reported to cause malaria in humans that include P. falciparum, P. vivax, P. malariae, P. ovale curtisi, P. ovale wallikeri, P. cynomolgi, P. knowlesi and more recently P. simium. Amongst them, the most genetically understood species is P. falciparum,...

Asynchronous Task-Based Parallelism in Seismic Imaging and Reservoir Modeling Simulations

Amani AlOnazi
The components of high-performance systems continue to become more complex on the road to exascale. This complexity is exposed at the level of: multi/many-core CPUs, accelerators (GPUs), interconnects (horizontal communication), and memory hierarchies (vertical communication). A crucial task is designing an algorithm and a programming model that scale to the same order of the HPC system size at multiple levels. This trend in HPC architecture more critically affects memory-intensive appli- cations than compute-bound applications. Accomplishing...

New Approaches in Bayesian Estimation of Earthquake Fault Model Parameters from InSAR and GPS

Rishabh Dutta
InSAR and GPS observations of Earth’s surface displacements are used to infer earthquake source parameters. Bayesian estimation of the source parameters produces the probability densities of the plausible parameters that are consistent with the observations. This facilitates analysis of the model parameters uncertainties and trade-offs regardless of the complexities (e.g., non-linearity, non-uniqueness, under- or over- parametrization, etc.) of the problem. In this thesis, I show various approaches, e.g., use of a priori information and innovative...

Fingerprinting Marine Macrophytes in Blue Carbon Habitats

Alejandra Ortega
Seagrass, mangrove, saltmarshes and macroalgae - the coastal vegetated habitats, offer a promising nature-based solution to climate change mitigation, as they sequester carbon in their living biomass and in marine sediments. Estimation of the macrophyte organic carbon contribution to coastal sediments is key for understanding the sources of blue carbon sequestration, and for establishing adequate conservation strategies. Nevertheless,identification of marine macrophytes has been challenging and current estimations are uncertain. In this dissertation, time- and cost-efficient...

Predictive Micro- and Meso-Mechanics Damage Models for Continuous Fiber-Reinforced Thermoplastic Composites

Ditho Ardiansyah Pulungan
Environmental issues enforce transportation sectors to limit their carbon dioxide emissions in various ways. Automotive manufacturers attempt to reduce carbon dioxide emission by seeking various strategies, e.g., increasing aerodynamic efficiency, using more fuel-efficient engines, reducing friction and wear of transmission systems, and, most importantly, by using lightweight materials and structures. This dissertation is a contribution toward a lightweight design of structures by proposing numerical models suitable for damage prediction of thermoplastic composite materials. In this...

Registration Year

  • 2023
    12
  • 2022
    580
  • 2021
    252
  • 2020
    225
  • 2019
    240
  • 2018
    1,133

Resource Types

  • Dissertation
    2,374
  • Dataset
    48
  • Other
    15
  • Software
    5

Affiliations

  • King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
    2,382