Matching Items (159)
Description
Nonlinear dispersive equations model nonlinear waves in a wide range of physical and mathematics contexts. They reinforce or dissipate effects of linear dispersion and nonlinear interactions, and thus, may be of a focusing or defocusing nature. The nonlinear Schrödinger equation or NLS is an example of such equations. It appears as a model in hydrodynamics, nonlinear optics, quantum condensates, heat pulses in solids and various other nonlinear instability phenomena. In mathematics, one of the interests is to look at the wave interaction: waves propagation with different speeds and/or different directions produces either small perturbations comparable with linear behavior, or creates solitary waves, or even leads to singular solutions. This dissertation studies the global behavior of finite energy solutions to the $d$-dimensional focusing NLS equation, $i partial _t u+Delta u+ |u|^{p-1}u=0, $ with initial data $u_0in H^1,; x in Rn$; the nonlinearity power $p$ and the dimension $d$ are chosen so that the scaling index $s=frac{d}{2}-frac{2}{p-1}$ is between 0 and 1, thus, the NLS is mass-supercritical $(s>0)$ and energy-subcritical $(s<1).$ For solutions with $ME[u_0]<1$ ($ME[u_0]$ stands for an invariant and conserved quantity in terms of the mass and energy of $u_0$), a sharp threshold for scattering and blowup is given. Namely, if the renormalized gradient $g_u$ of a solution $u$ to NLS is initially less than 1, i.e., $g_u(0)<1,$ then the solution exists globally in time and scatters in $H^1$ (approaches some linear Schr"odinger evolution as $ttopminfty$); if the renormalized gradient $g_u(0)>1,$ then the solution exhibits a blowup behavior, that is, either a finite time blowup occurs, or there is a divergence of $H^1$ norm in infinite time. This work generalizes the results for the 3d cubic NLS obtained in a series of papers by Holmer-Roudenko and Duyckaerts-Holmer-Roudenko with the key ingredients, the concentration compactness and localized variance, developed in the context of the energy-critical NLS and Nonlinear Wave equations by Kenig and Merle. One of the difficulties is fractional powers of nonlinearities which are overcome by considering Besov-Strichartz estimates and various fractional differentiation rules.
ContributorsGuevara, Cristi Darley (Author) / Roudenko, Svetlana (Thesis advisor) / Castillo_Chavez, Carlos (Committee member) / Jones, Donald (Committee member) / Mahalov, Alex (Committee member) / Suslov, Sergei (Committee member) / Arizona State University (Publisher)
Created2011
Description
This thesis outlines the development of a vector retrieval technique, based on data assimilation, for a coherent Doppler LIDAR (Light Detection and Ranging). A detailed analysis of the Optimal Interpolation (OI) technique for vector retrieval is presented. Through several modifications to the OI technique, it is shown that the modified technique results in significant improvement in velocity retrieval accuracy. These modifications include changes to innovation covariance portioning, covariance binning, and analysis increment calculation. It is observed that the modified technique is able to make retrievals with better accuracy, preserves local information better, and compares well with tower measurements. In order to study the error of representativeness and vector retrieval error, a lidar simulator was constructed. Using the lidar simulator a thorough sensitivity analysis of the lidar measurement process and vector retrieval is carried out. The error of representativeness as a function of scales of motion and sensitivity of vector retrieval to look angle is quantified. Using the modified OI technique, study of nocturnal flow in Owens' Valley, CA was carried out to identify and understand uncharacteristic events on the night of March 27th 2006. Observations from 1030 UTC to 1230 UTC (0230 hr local time to 0430 hr local time) on March 27 2006 are presented. Lidar observations show complex and uncharacteristic flows such as sudden bursts of westerly cross-valley wind mixing with the dominant up-valley wind. Model results from Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS®) and other in-situ instrumentations are used to corroborate and complement these observations. The modified OI technique is used to identify uncharacteristic and extreme flow events at a wind development site. Estimates of turbulence and shear from this technique are compared to tower measurements. A formulation for equivalent wind speed in the presence of variations in wind speed and direction, combined with shear is developed and used to determine wind energy content in presence of turbulence.
ContributorsChoukulkar, Aditya (Author) / Calhoun, Ronald (Thesis advisor) / Mahalov, Alex (Committee member) / Kostelich, Eric (Committee member) / Huang, Huei-Ping (Committee member) / Phelan, Patrick (Committee member) / Arizona State University (Publisher)
Created2013
Description
It is possible in a properly controlled environment, such as industrial metrology, to make significant headway into the non-industrial constraints on image-based position measurement using the techniques of image registration and achieve repeatable feature measurements on the order of 0.3% of a pixel, or about an order of magnitude improvement on conventional real-world performance. These measurements are then used as inputs for a model optimal, model agnostic, smoothing for calibration of a laser scribe and online tracking of velocimeter using video input. Using appropriate smooth interpolation to increase effective sample density can reduce uncertainty and improve estimates. Use of the proper negative offset of the template function has the result of creating a convolution with higher local curvature than either template of target function which allows improved center-finding. Using the Akaike Information Criterion with a smoothing spline function it is possible to perform a model-optimal smooth on scalar measurements without knowing the underlying model and to determine the function describing the uncertainty in that optimal smooth. An example of empiric derivation of the parameters for a rudimentary Kalman Filter from this is then provided, and tested. Using the techniques of Exploratory Data Analysis and the "Formulize" genetic algorithm tool to convert the spline models into more accessible analytic forms resulted in stable, properly generalized, KF with performance and simplicity that exceeds "textbook" implementations thereof. Validation of the measurement includes that, in analytic case, it led to arbitrary precision in measurement of feature; in reasonable test case using the methods proposed, a reasonable and consistent maximum error of around 0.3% the length of a pixel was achieved and in practice using pixels that were 700nm in size feature position was located to within ± 2 nm. Robust applicability is demonstrated by the measurement of indicator position for a King model 2-32-G-042 rotameter.
ContributorsMunroe, Michael R (Author) / Phelan, Patrick (Thesis advisor) / Kostelich, Eric (Committee member) / Mahalov, Alex (Committee member) / Arizona State University (Publisher)
Created2012
Description
Leadership styles in the U.S. have gone through great changes in the past decades. New leadership styles have proven to be more effective than those of the past. There are certain characteristics that leaders today must have in order to effectively motivate their employees intrinsically. This report explains how certain leadership characteristics can lead to desirable or undesirable behaviors from employees. The information provided in this report was retrieved from a study I conducted with Peter Hom, Professor of Management of Arizona State University, and articles on servant leadership written by two extremely knowledgeable individuals on this topic, Adam Grant, Professor of Management at the University of Pennsylvania, and Robert Liden, Professor of Management at the University of Illinois at Chicago. Several other articles from credible sources were also used to provide support for this report. The report also includes numerous diagrams that help interpret the information provided.
The report is divided into several sections:
• Traditional Leadership style and rewards
• Existing literature on job relational design
• Servant leadership
• Surveys
• Data analysis
• Conclusion
From this research, it can be concluded that certain leadership qualities can contribute to an increase in intrinsic motivation to subordinates. Also, there are certain traits that allow managers to have a positive impact on subordinates. This study also provides leaders with suggestions on how to increase subordinates’ concerns for customers, which will translate into more productive work from employees.
The report is divided into several sections:
• Traditional Leadership style and rewards
• Existing literature on job relational design
• Servant leadership
• Surveys
• Data analysis
• Conclusion
From this research, it can be concluded that certain leadership qualities can contribute to an increase in intrinsic motivation to subordinates. Also, there are certain traits that allow managers to have a positive impact on subordinates. This study also provides leaders with suggestions on how to increase subordinates’ concerns for customers, which will translate into more productive work from employees.
ContributorsPulley, Travon Larnell (Author) / Hom, Peter (Thesis director) / Adelheid, Thieme (Committee member) / Barrett, The Honors College (Contributor) / Department of Marketing (Contributor) / W. P. Carey School of Business (Contributor) / Department of Management (Contributor)
Created2014-05
Description
Mathematical epidemiology, one of the oldest and richest areas in mathematical biology, has significantly enhanced our understanding of how pathogens emerge, evolve, and spread. Classical epidemiological models, the standard for predicting and managing the spread of infectious disease, assume that contacts between susceptible and infectious individuals depend on their relative frequency in the population. The behavioral factors that underpin contact rates are not generally addressed. There is, however, an emerging a class of models that addresses the feedbacks between infectious disease dynamics and the behavioral decisions driving host contact. Referred to as “economic epidemiology” or “epidemiological economics,” the approach explores the determinants of decisions about the number and type of contacts made by individuals, using insights and methods from economics. We show how the approach has the potential both to improve predictions of the course of infectious disease, and to support development of novel approaches to infectious disease management.
ContributorsPerrings, Charles (Author) / Castillo-Chavez, Carlos (Author) / Chowell-Puente, Gerardo (Author) / Daszak, Peter (Author) / Fenichel, Eli P. (Author) / Finnoff, David (Author) / Horan, Richard D. (Author) / Kilpatrick, A. Marm (Author) / Kinzig, Ann (Author) / Kuminoff, Nicolai (Author) / Levin, Simon (Author) / Morin, Benjamin (Author) / Smith, Katherine F. (Author) / Springborn, Michael (Author) / Simon M. Levin Mathematical, Computational and Modeling Sciences Center (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / W.P. Carey School of Business (Contributor) / Economics (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor)
Created2015-12-01
Description
The Community Assistant position at Arizona State University is dealing with an issue of poor year-to-year retention. Currently, a large number of Community Assistants who could return for another year are choosing not to, which is further exacerbated by the fact that graduating Community Assistants cannot stay even if they wanted to because the position must be held by active students. Through research, interviews, and testimony, this paper constructs what the Community Assistant role entails and the priorities that the role instills in current Community Assistants at ASU. It then seeks to answer the question of why low levels of year-to-year retention matter and why so many are choosing to move to different positions after their first year has ended. By building from the information provided by current Community Assistants and various management theories from a variety of sources, this paper offers actionable recommendations for Arizona State University Housing to increase retention and motivation within the Community Assistant position.
ContributorsKnauer, Remington (Author) / Arrfelt, Mathias (Thesis director) / Hom, Peter (Committee member) / Department of Management and Entrepreneurship (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Differences between cultures have been (and continue to be) examined by researchers all over the world. Prominent studies performed by organizations such as GLOBE and Hofstede have created a foundation for our understanding of how culture affects business in different countries. They also inspired our study, which investigates how employment benefits vary in different cultures. We examined the difference in employee benefit preference of Austria and Germany compared to America and how that affects their perception of the organization. Specifically, we studied how employees in those countries would react to an increase in wage or an increase in vacation time. Each participant read a hypothetical scenario in which they received one of the two benefits. The alternative benefit was not disclosed to them. After reading about the reward, they were asked various questions about the company. These questions gauged their belief in the ability of the organization, their benevolence toward the organization, their perception of the integrity of the organization, their trust in the organization, their turnover intentions, and their obligation felt towards the organization.
Two of the six variables tested yielded statistically significant results after we performed a univariate analysis of variance test on each of the variables. The two variables that yielded statistically significant results were belief in the integrity of the organization and benevolence toward the organization. Americans expressed more benevolence and belief in the integrity of their organization when they received more vacation time, while Europeans exhibited the opposite reaction (to a lesser degree). These results could provide insight to companies that are looking to strengthen company culture or increase motivation of employees. The variables with non-significant results could be attributed to globalization, limitations of our study, or the concept of scarcity.
Two of the six variables tested yielded statistically significant results after we performed a univariate analysis of variance test on each of the variables. The two variables that yielded statistically significant results were belief in the integrity of the organization and benevolence toward the organization. Americans expressed more benevolence and belief in the integrity of their organization when they received more vacation time, while Europeans exhibited the opposite reaction (to a lesser degree). These results could provide insight to companies that are looking to strengthen company culture or increase motivation of employees. The variables with non-significant results could be attributed to globalization, limitations of our study, or the concept of scarcity.
ContributorsMackey, Henry Aloysius (Author) / Baer, Mike (Thesis director) / Hom, Peter (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Department of Management and Entrepreneurship (Contributor) / Department of Information Systems (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
This thesis analyzes the importance of positive relationships between managers and their
employees. It attempts to define what a positive work relationship is and how it can influence the
work environment. Through information found from case studies and surveys it is clear that a
good manager, as defined in this work, has a large impact on employee job satisfaction,
motivation and perceived retention rate. Using popular theories and studies I will show the
support I have for the analysis of my results as well as studies which prove my results to be
flawed.
employees. It attempts to define what a positive work relationship is and how it can influence the
work environment. Through information found from case studies and surveys it is clear that a
good manager, as defined in this work, has a large impact on employee job satisfaction,
motivation and perceived retention rate. Using popular theories and studies I will show the
support I have for the analysis of my results as well as studies which prove my results to be
flawed.
ContributorsAmmons, Karilee Rose (Author) / Hom, Peter (Thesis director) / Eric, Knott (Committee member) / Department of Management and Entrepreneurship (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
While non-invasive breast cancer treatments may be considered less costly in the short-term, over the course of a lifetime, a more aggressive treatment can be overall less costly, especially with recurrence cases; however, these more aggressive treatments are not necessarily covered by insurance and are difficult to discuss in the short amount of time in physician consultations. This analysis studied data from 982 women diagnosed with breast cancer over a five-year period to evaluate monetary costs associated with treatment options and incorporated five in-depth interviews to understand experiences and non-monetary costs. Data showed the most expensive option was a unilateral mastectomy with radiation therapy and the least costly option was breast conserving surgery. Interviews determined each woman evaluated the monetary costs with each treatment but most heavily focused on personal values, biases and recommended opinions when deciding on a treatment. The use of prompt sheets before physician appointments and consultations, along with the addition of financial counselor meeting with each patient can improve patient satisfaction and alleviate stress by simplifying a woman's choice in deciding a treatment. In addition, increased insurance coverage to include every treatment chosen by women (rather than on a case-by-case basis), specifically contralateral prophylactic mastectomy and additional screening options, could decrease long term costs \u2014 both monetarily and in quality of life for patients.
ContributorsOsumi, Alana (Author) / LaRosa, Julia (Thesis director) / Sivanantham, Jai (Committee member) / Barrett, The Honors College (Contributor) / W.P. Carey School of Business (Contributor)
Created2018-12
Description
In 2016, in the United States alone, the cosmetics industry made an estimated 62.46 billion dollars in revenue (Revenue of the Cosmetic Industry in the U.S. 2002-2016 | Forecast). With a consistent increase in sales in the last several years, the industry has reached continued success even during times of hardship, such as the Great Recession of 2008. The use of Corporate Social Responsibility (CSR), external campaigns, and thoughtful packaging and ingredients resonates with targeted consumers. This has served as an effective strategy to maintain growth in the industry. Cosmetic companies promote their brand image using these sustainability tactics, but there seems to be a lack of transparency in this unregulated industry. The purpose of this thesis is to determine if the cosmetics industry is a good steward of the sustainability movement. Important terms and concepts relating to the industry will be discussed, then an analysis of sustainability focused cosmetic brands will be provided, which highlights the extent to which these brands engage in activities that promote sustainability. This is followed by an application of findings to a company that could benefit from using such practices. Overall, the analysis of the different brands proved to be shocking and disappointing. This is due to the sheer amount that scored very poorly based on the sustainability criteria developed. The cosmetics industry is too inconsistent and too unregulated to truly act as a good steward for sustainability. Though some companies in the industry succeed, these accomplishments are not consistent across all cosmetic companies. Hence, the cosmetics industry as a good steward for sustainability can only be as strong as its weakest link.
ContributorsMamus, Sydney Wasescha (Author) / Ostrom, Amy (Thesis director) / Kristofferson, Kirk (Committee member) / Department of Marketing (Contributor) / W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05