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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Numerical modelling of non-linear wave-induced nearshore circulation

MacDonald, Neil Joseph January 1998 (has links)
No description available.
32

The use of habit-change strategies in demarketing: reducing excessive discretionary consumption

Gallagher, Katherine 05 1900 (has links)
According to the Bruntland Commission, sustainable development requires consumers in industrialized nations to reduce significantly their consumption of resources. This research brings a new perspective to the reduction of discretionary consumption, using both theoretical and empirical approaches. Demarketing programs have often been unable to achieve sustained reductions in consumption. It is argued here that they have incorrectly treated demand reduction as a variation on the usual marketing problem of building demand, when it is (1) more complex than typical marketing problems, and (2) essentially similar to clinical habit change problems. The dissertation reviews the literature on habits and automated processes, introduces the concept of “habit-like” behavior, and argues that reducing discretionary consumption can often be framed as a habit-change problem. The Prochaska and DiClemente (1984) Revolving Door Model of Behavior Change (RDM) describes how people change habitual behaviors in clinical situations. Study 1, an energy conservation (cold water laundry washing) survey (n=340), using a decisional balance framework, indicated that the RDM generalizes to demarketing situations and that it is consumers’ perceptions of the importance of disadvantages, not advantages, that influence consumption reductions. The research develops new theory to explain habit-like behavior changes. Based on previous theory and findings on automated processes, it is proposed that changing habit-like behavior proceeds in three steps: de-automation, volitional behavior change, and consolidation. Study 2 was a laboratory experiment (n= 117) in which two demarketing approaches (the traditional approach and the habit-change approach) competed in two situations (when the consumption behavior targeted for change was under volitional control, and when it was habit-like). Contrary to expectations, a persuasive message supplemented by limited practice of the new behavior was more effective when the old behavior was volitional than when it was habit-like, suggesting that the disadvantages of changing are more evident to people whose behavior is habit-like. There are two important practical implications: that (1) segmentation based on the RDM stages of change may be more powerful than other approaches; and (2) it is more important to address disadvantages of reducing consumption than to emphasize advantages. / Business, Sauder School of / Graduate
33

Strong dynamics and lattice gauge theory

Schaich, David January 2012 (has links)
Thesis (Ph.D.)--Boston University / In this dissertation I use lattice gauge theory to study models of electroweak symmetry breaking that involve new strong dynamics. Electroweak symmetry breaking (EWSB) is the process by which elementary particles acquire mass. First proposed in the 1960s, this process has been clearly established by experiments, and can now be considered a law of nature. However, the physics underlying EWSB is still unknown, and understanding it remains a central challenge in particle physics today. A natural possibility is that EWSB is driven by the dynamics of some new, strongly-interacting force. Strong interactions invalidate the standard analytical approach of perturbation theory, making these models difficult to study. Lattice gauge theory is the premier method for obtaining quantitatively-reliable, nonperturbative predictions from strongly-interacting theories. In this approach, we replace spacetime by a regular, finite grid of discrete sites connected by links. The fields and interactions described by the theory are likewise discretized, and defined on the lattice so that we recover the original theory in continuous spacetime on an infinitely large lattice with sites infinitesimally close together. The finite number of degrees of freedom in the discretized system lets us simulate the lattice theory using high-performance computing. Lattice gauge theory has long been applied to quantum chromodynamics, the theory of strong nuclear interactions. Using lattice gauge theory to study dynamical EWSB, as I do in this dissertation, is a new and exciting application of these methods. Of particular interest is non-perturbative lattice calculation of the electroweak S parameter. Experimentally S ~ -0.15(10), which tightly constrains dynamical EWSB. On the lattice, I extract S from the momentum-dependence of vector and axial-vector current correlators. I created and applied computer programs to calculate these correlators and analyze them to determine S. I also calculated the masses and other properties of the new particles predicted by these theories. I find S > 0.1 in the specific theories I study. Although this result still disagrees with experiment, it is much closer to the experimental value than is the conventional wisdom S > 0.3. These results encourage further lattice studies to search for experimentally viable strongly-interacting theories of EWSB.
34

Groups, Graphs, and Symmetry-Breaking

Potanka, Karen Sue 28 April 1998 (has links)
A labeling of a graph G is said to be r-distinguishing if no automorphism of G preserves all of the vertex labels. The smallest such number r for which there is an r-distinguishing labeling on G is called the distinguishing number of G. The distinguishing set of a group Gamma, D(Gamma), is the set of distinguishing numbers of graphs G in which Aut(G) = Gamma. It is shown that D(Gamma) is non-empty for any finite group Gamma. In particular, D(D<sub>n</sub>) is found where D<sub>n</sub> is the dihedral group with 2n elements. From there, the generalized Petersen graphs, GP(n,k), are defined and the automorphism groups and distinguishing numbers of such graphs are given. / Master of Science
35

An Empirical Study of API Breaking Changes in Bioconductor

Chowdhury, Hemayet Ahmed 10 January 2023 (has links)
Bioconductor is the second largest R software package repository that is primarily used for the analysis of genomic and biological data. With downloads exceeding millions in recent years, the widespread growth of the repository's adoption can be attributed to it's diverse selection of community-created packages, written in the programming language R, that allow statistical methodologies for analysis and modelling of data. However, as these packages evolve, their APIs go through changes that can break existing user code. Fixing these API breaking changes whenever a package is updated can be frustrating and time-consuming, especially since a large fraction of the user community are researchers who do not necessarily have software engineering background. In that context, we first present a tool that can detect syntactic API breaking changes between two released versions of a library written in R through static analysis of the package source code. This tool can be of utility to R package developers, so that they can more comprehensively report or handle the breaking changes in their releases, and to R package users, who want to be aware of the API differences that may exist between two releases before upgrading the libraries in their code. Through the use of this tool and manual inspection, we also conducted an empirical study of the breaking changes and backward incompatibility in Bioconductor packages. We studied the 100 most downloaded packages in the repository and found that 28% of all packages releases are backward incompatible. We also found that 55% of these breaking changes go undocumented and developers don't maintain semantic versioning for 22% of the releases. Finally, we manually inspected 10 library releases that consisted of breaking changes and found 2% of the API-s to affect 31 client projects. / Master of Science / Bioconductor is a software repository that consists of over 2000 software libraries. These libraries can provide users with reusable functions, or APIs, to perform statistical and graphical data analysis. The developers of these libraries will generally make timely updates to the library source code and the functions for various maintainability purposes. However, when clients install these library updates in their existing code, their code might not compile, run or behave the same way it used to anymore due to the changes made in the APIs of the libraries. Such a library release that consists of changes that can potentially break older code is considered to be backward incompatible. Without proper documentation from the library developer's side, fixing these issues can be time consuming as the client might have to manually look at the changes made in the library's source code. In order to tackle this issue, we first present a tool that can analyse two versions of a library and identify a subset of the breaking changes in the API. This can be helpful for both the users and the developers of the libraries to be aware of any breaking changes that exist in a new release. Afterwards, we conduct a study on the Bioconductor ecosystem to see how serious the problem of backward incompatibility really is by studying the top 100 most downloaded packages from the repository. We see that 28% of the releases across these 100 packages are backward incompatible. Since clients are likely to be using multiple libraries at once, this figure can potentially cause frequent issues in client code. We then go on to check how often developers maintain the correct release protocols when updating their libraries. These include versioning the releases in correct ways, so as to let the users be aware of what releases may be backward incompatible and documenting any breaking changes that occur in a NEWS file that users have access to. In that aspect, we find that 22% of the releases are not versioned correctly and roughly 55% of the breaking changes in the API are not documented. Finally, we investigate how frequently these breaking changes can actually affect client code. Here, we manually inspect 10 releases with a high number of a subset of the breaking changes and find 31 projects that implement these APIs, which would break upon a library update.
36

Simulation of breaking wave by SPH method coupled with k-¿ model / Simulation des vagues déferlantes par la méthode SPH couplée à un modèle k-¿

Shao, Songdong January 2006 (has links)
The paper employs a Reynolds-averaged Navier¿Stokes (RANS) approach to investigate the time-dependent wave breaking processes. The numerical model is the smoothed particle hydrodynamic (SPH) method. It is a mesh-free particle approach which is capable of tracking the free surfaces of large deformation in an easy and accurate way. The widely used two-equation k¿¿ model is chosen as the turbulence model to couple with the incompressible SPH scheme. The numerical model is employed to reproduce cnoidal wave breaking on a slope under two different breaking conditions¿spilling and plunging. The computed free surface displacements, turbulence intensities and undertow profiles are in good agreement with the experimental data and other numerical results. According to the computations, the breaking wave characteristics are presented and discussed. It is shown that the SPH method provides a useful tool to investigate the surf zone dynamics.
37

An Analysis of The Effect of 3-D Groove Insert Design on Chip Breaking Chart

Avanessian, Alfred 25 January 2005 (has links)
Abstract Prediction of chip-breaking in machining is an important task for automated manufacturing. There are chip-breaking limits in machining chip-breaking chart, which determine the chip-breaking range. This thesis presents a study of the effect of 3-D groove insert parameters on chip breaking chart. Based on the chip-breaking criteria, the critical feed rate is formulated through an analysis of up-curl chip formation for 3-D grooves. Also in order to predict chip-breaking limits, for protruded insert grooves in finish machining, analytical models are established. In the analytical models, minimum and maximum depth of cut are identified for using different chip breaking models. As well insert nose radius effects on chip thickness for small depth of cut are studied. In the end, the analytical critical feed rate model is extended to finish machining with 3-D chipbreaking grooves.
38

Study of the Characteristics of Breaking Wave and the Impulse due to Breaking Wave on Gentle Slope Bottom

Tseng, Wen-Jer 13 June 2007 (has links)
The major purpose of this study is focused on the characteristics of the breaker and the impulse caused by wave breaking. Two-dimensional surface regular gravity water waves propagating on a gentle sloping bottom are considered and the consecutively temporal-spatial evolution of wave traveling form deep water to shallow water is also investigated. Two perturbation parameters, bottom slope and the deep water wave amplitude , proposed by Chen et al.(1992~2005), are introduced in this problem. Also, two different systems in fluid mechanics are used and the theoretical results are corrected to order , including nonlinear quantities, in both of Eulerian and Lagrangian systems. Considering the point of view that the horizontal velocity of a specified fluid particle is equal to the wave celerity while the wave begins to break, some important physical phenomena, such as the evolution of wave profile, the trajectory of fluid particle, and the water wave pressure, are described in this analytical analysis. Furthermore, the wave length, wave height, water depth and wave steepness of breaking wave are solved. To modify the insufficiency of former semi-empirical formula for the impulse due to wave breaking, a theoretical formula is proposed by integrating the resulting water wave pressure form mean still water level to free surface. Previous experimental studies are employed to verify the theoretical results. For wave for a further verification on the characteristics of wave breaking, some measurements on the movement of fluid particle, wave force and impulse wave conducted. Reasonable agreements can be found from the comparisons. It is concluded that consideration of wave nonlinearity is necessary while dealing with wave breaking problem.
39

Os Caminhos do mal – uma análise semiótica de Breaking Bad

Oliveira, Luiza Monteiro de Barros 25 April 2017 (has links)
Submitted by Fabiano Vassallo (fabianovassallo2127@gmail.com) on 2017-04-20T19:09:12Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTACAO-LuizaMonteiro.pdf: 3560286 bytes, checksum: ad8c0fa7a9b1fc3a2a2d5137f21a3174 (MD5) / Approved for entry into archive by Josimara Dias Brumatti (bcgdigital@ndc.uff.br) on 2017-04-25T14:52:26Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTACAO-LuizaMonteiro.pdf: 3560286 bytes, checksum: ad8c0fa7a9b1fc3a2a2d5137f21a3174 (MD5) / Made available in DSpace on 2017-04-25T14:52:26Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) DISSERTACAO-LuizaMonteiro.pdf: 3560286 bytes, checksum: ad8c0fa7a9b1fc3a2a2d5137f21a3174 (MD5) / A presente dissertação de mestrado propõe-se a analisar, por meio do aparato da semiótica francesa, a série de televisão Breaking bad, transmitida entre 2008 e 2013 pelo canal norte-americano AMC. Parte da chamada nova “era de ouro” da televisão americana, a série criada por Vince Gilligan apresenta uma narrativa inventiva que conquistou tanto público quanto crítica, sobretudo pelo apelo de seu protagonista, Walter White. A partir do percurso gerativo de sentido de Algirdas Greimas, a análise concentrase nos níveis narrativos e discursivos para acompanhar quais estratégias são empregadas nesta obra audiovisual. Em especial, propomos um estudo sobre as paixões do protagonista e os valores que são postos em jogo por meio da articulação entre recursos verbais e visuais / This work uses french semiotics to analyse the TV series Breaking bad, transmited between 2008 and 2013 on AMC channel in the United States. Identified as part of the so called new american TV “Golden age”, the series created by Vince Gilligan features an inventive narrative that was equally accepted by the audience and TV critics, with its protagonist, Walter White, as the greatest cause of its success. In this work, the narrative and discoursive levels of Algirdas Greimas’ generative meaning trajectory are used to follow which strategies are used in this audiovisual work. In special, we propose a study about the protagonist’s passions and the values that are displayed through the articulation between verbal and visual recourses
40

One-Dimensional Mass-Spring Chains Supporting Elastic Waves with Non-Conventional Topology

Deymier, Pierre, Runge, Keith 16 April 2016 (has links)
There are two classes of phononic structures that can support elastic waves with non-conventional topology, namely intrinsic and extrinsic systems. The non-conventional topology of elastic wave results from breaking time reversal symmetry (T-symmetry) of wave propagation. In extrinsic systems, energy is injected into the phononic structure to break T-symmetry. In intrinsic systems symmetry is broken through the medium microstructure that may lead to internal resonances. Mass-spring composite structures are introduced as metaphors for more complex phononic crystals with non-conventional topology. The elastic wave equation of motion of an intrinsic phononic structure composed of two coupled one-dimensional (1D) harmonic chains can be factored into a Dirac-like equation, leading to antisymmetric modes that have spinor character and therefore non-conventional topology in wave number space. The topology of the elastic waves can be further modified by subjecting phononic structures to externally-induced spatio-temporal modulation of their elastic properties. Such modulations can be actuated through photo-elastic effects, magneto-elastic effects, piezo-electric effects or external mechanical effects. We also uncover an analogy between a combined intrinsic-extrinsic systems composed of a simple one-dimensional harmonic chain coupled to a rigid substrate subjected to a spatio-temporal modulation of the side spring stiffness and the Dirac equation in the presence of an electromagnetic field. The modulation is shown to be able to tune the spinor part of the elastic wave function and therefore its topology. This analogy between classical mechanics and quantum phenomena offers new modalities for developing more complex functions of phononic crystals and acoustic metamaterials.

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