Theses and Dissertations

Fall 2017

Yuan, Yuan

reconcile the data. Among various approaches for optimization with uncertainty, chance constraint problem is a natural way to quantify the reliability of the solutions by setting a restriction on the level of the probability that the constraints are satisfied. In the case that multiple constraints should be

satisfied simultaneously, joint chance constraint is appropriate to model the uncertainties. However, joint chance constraint problem is generally intractable and a variety of methods are available to approximate it into tractable forms. Robust optimization with the distribution-free property is an approach

models. This thesis develops a novel robust optimization framework to consider the uncertain nonlinear optimization problems. The thesis provides practical applications as well. An economic optimization problem is investigated for steam generation and water distribution for SAGD (steam-assisted-gravity

Fall 2022

Mehranfar, Mahyar

longitudinal direction. The second objective was to test the performance of the new technique on a variety of pipeline dents. The developed method is based on the three-dimensional mathematical model proposed by Okoloekwe et al. In the original model proposed by Okoloekwe et al, it was assumed that the

the pipeline can cause lower pressure capacity. Analytical and numerical models, such as the finite element method (FEA), can predict this issue. The traditional way for recognizing the seriousness of the dent is to test the dent depth. But unfortunately, this method cannot predict the probability of

failure accurately. Based on previous research, there are two ways to assess the seriousness of the dents. The first method is to model the pipe by finite element method. While very accurate, the finite element method is very computationally demanding and time consuming. The second method utilizes the

Fall 2009

Avila-Flores, Rafael

. Although increased isolation may reduce the probability of occurrence at a given site, highly isolated locations may support high population densities. Contrary to my original predictions, I did not detect significant impacts of human-related factors on BTPD distribution and abundance.

decline with the occurrence of most intense drought suggests a prominent role of drought in the population collapse. Overall, patterns of BTPD occurrence and abundance in Chihuahua are greatly influenced by spatial and temporal variation in forage cover. Although BTPDs were more likely to occur in open

areas with short vegetation, increased forage cover positively predicted occurrence. High levels of forage cover during the dry season were positively related with BTPD density, juvenile production and population rate of change, but forage cover during the preceding rainy season was a negative

Spring 2018

Ma, Zhiwei

these trained models are shown to be both reliable and satisfactory. Next, a series of synthetic SAGD models based on typical Athabasca oil reservoir properties and operating conditions is constructed. Heterogeneities are modeled by randomly sampling distribution, volume, and orientation of shale

barriers and lean zones from several probability distributions inferred from field data, and are superposed to the base homogenous models. Many parameterization schemes are investigated to extract input and output parameters from production time-series data and heterogeneous configurations, respectively

is of great interest to propose a feasible SAGD analysis alternative that is capable of utilizing these field data for production analysis and heterogeneities characterization. Data-driven modeling techniques, which involve data analytics and implementation of artificial intelligence (AI) methods for

Spring 2019

Wei, Ziling

maximize the average throughput of the network, an optimal stopping strategy with threshold-based structure is derived in this scheme. To obtain the threshold, a low complexity algorithm is proposed to derive the stationary probability distribution of the energy level of each relay, and then, the threshold

challenges, with four research components.The first research component focuses on the optimal slot length configuration in cognitive radio networks. A slot length configuration scheme with imperfect spectrum sensing is proposed in this research. In the proposed scheme, the spectrum sensing result is

With the fast growth of mobile data traffic, spectrum scarcity has become a serious problem to the development of wireless networks. Due to the limited available spectrum resources, it is critical to improve the spectrum efficiency. Cognitive radio, opportunistic scheduling, and non-orthogonal

Fall 2017

Qu, Yuanzhuo

identical distributions, and the third design compensates for the probability inaccuracy caused by the variations using a two-step switching process. All three designs can generate high-quality random sequences without using complicated post-processing or real-time feedback circuits. Moreover, general

the variation challenges, three variation-resilient TRNG designs based on STT-MTJs are proposed in this thesis work. The first design utilizes a parallel structure with multiple devices to minimize the variation effects, the second design leverages the symmetry of an MTJ pair to take advantage of two

In the Internet of Things (IoT) era, security has increasingly become a challenge, so encryption has been widely used to protect data. Random number generators (RNGs), as an essential part of cryptographic systems, are implemented in connected devices for information security. However, inadequate

Fall 2017

Neilson, Eric W

The degree to which predator and prey distributions overlap in space influences the probability of encounters between predator and prey, kills of prey, and consequently, how each species’ abundance varies in time and in space. Predator and prey attempt to increase or decrease overlap respectively

for moose was available due to human disturbance. Further, I found that a higher proportion of moose were killed as the distance to oil sands mines decreased. I also found that wolves selected to move on linear features associated with oil extraction and such selection facilitated faster movement

through movement and habitat selection, processes that are sensitive to habitat heterogeneity. If predator and prey respond differently to novel habitat heterogeneity such as a zone of influence in and around human disturbance, it may provide prey with a refuge or facilitate predator hunting efficiency

Fall 2013

Ball, Jeffrey R

spatial distribution or probability of nest predation by the majority of nest predators was strongly affected by edge proximity. Of all the predators monitored, only bears and deer mice were more common near edges but they depredated few nests. I also did not find strong support for a negative edge

Nest predation is a major source of reproductive failure for many species of songbirds. Habitat fragmentation by human land use creates edge habitat that can alter predator-prey dynamics, create ecological traps, and reduce the amount of high quality habitat available for sustaining bird

effect of linear features on songbird nest fate (n = 571 nests) relative to forest interiors. Ground nest survival was marginally higher near edges and ground and shrub nest survival was marginally higher where squirrels were absent. In contrast, the survival of canopy nests was higher away from the edge

Fall 2015

D'Amours, Réal

the papers constitutes a distinct scientific study, as a group, they are unified by their collective focus on transport within and exchange between the atmospheric layers. After a brief overview of the three main layers that account for most of the atmosphere's mass, and of their interfaces, the

describing the time evolution of the probability density distribution of those particles in phase-space. The Lagrangian transport models developed and used operationally at the Canadian Meteorological Centre (CMC) of Environment Canada are presented, and the various simulated physical processes are also

troposphere and the planetary boundary layer are examined in detail with the aid of a simple diagnostic model developed to estimate the turbulent kinetic energy and the turbulent velocity variances. This model produces plausible profiles of the vertical velocity variance σw2, and of the vertical distribution

Spring 2020

Yusuf, Yishak

production. The flow contraction caused by the presence of these slots leads to significant pressure loss in the flow increasing the probability of well failure due to plugging. Scrutinizing the underlying physics reveals a flow convergence phenomenon in the incoming flow of produced oil which is

rectangular orifice. The research first investigates the flow through an open slot to model the pressure loss as a function of AR and the flow Reynolds number. A semi-empirical model is developed for the pressure loss coefficient as a function of AR and flow convergence. The analytical modeling is based on

the 1 dimensional Navier-Stokes equation and an asymptotic velocity transition model for a Gaussian velocity distribution. The loss coefficient decreased for increasing AR as per the model, agreeing with the hypothesized relationship regarding the streamline curvature and AR. A large scale flow