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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.
341

Effectiveness of grouping middle school students based on learning modality preferences on vibrato acquisition

Varga, Anthony Carman 12 March 2016 (has links)
The purpose of this study was to examine the effectiveness of grouping middle school students by learning modality preferences on vibrato acquisition. Traditional approaches to teaching vibrato synthesize reading and listening to elicit an appropriate tactile response, however, Ornstein (1995) identified this approach as a narrow scope suited to a "hypothetical average student" (p.105). Keefe (1985) proposed learning styles as a reliable lens for understanding the individuality of learning. Music education research has a pronounced lack of pedagogical studies addressing technical development particularly regarding stringed instruments. A majority of vibrato research in particular has been regulated to diagnostic studies of the behavior of its inherent acoustic properties. Of the several tutorial vibrato studies that exist, namely those by Gillespie (1997), and Shepherd (2004), few examined beyond two of the primary sensory (e.g., visual and auditory) learning modes identified by Swassing and Barbe (1979). This study challenged traditional approaches by accommodating individual sensory preferences as the most promising path to learning vibrato. Dominant learning preferences of 60 middle school orchestra students were identified using VARK (Fleming, 2001), an instrument whose name is derived from an acronym for Visual, Auditory, Read/Write, and Kinesthetic. Based on VARK (Fleming, 2001), results, four groups were created corresponding to three learning preferences and a control group. Pretest recordings were made to evaluate existent vibrato abilities and all subjects participated in six weeks of intervention vibrato lessons where teaching was deliberately matched to each group's learning preference. The control group was taught using a traditional class method book. Following the intervention period, posttest recordings were made as an exit assessment. All recordings were evaluated by a panel of qualified string educators using Gillespie's (1993) vibrato evaluation instrument and three data sets were constructed corresponding to means of the pretest, posttest, and a means of difference between the two. Analysis included measures of central tendency, Kruskal-Wallis H test and frequency distributions. Descriptive statistics were computed for grade, gender, and instrument to examine latent peripheral relationships and no significant differences were found between learning preference groups and the control group compelling the researcher to accept the null hypothesis.
342

Homogeneity in supergravity

Hustler, Noel January 2016 (has links)
This thesis is divided into three main parts. In the first of these (comprising chapters 1 and 2) we present the physical context of the research and cover the basic geometric background we will need to use throughout the rest of this thesis. In the second part (comprising chapters 3 to 5) we motivate and develop the strong homogeneity theorem for supergravity backgrounds. We go on to prove it directly for a number of top-dimensional Poincaré supergravities and furthermore demonstrate how it also generically applies to dimensional reductions of those theories. In the third part (comprising chapters 6 and 7) we show how further specialising to the case of symmetric backgrounds allows us to compute complete classifications of such backgrounds. We demonstrate this by classifying all symmetric type IIB supergravity backgrounds. Next we apply an algorithm for computing the supersymmetry of symmetric backgrounds and use this to classify all supersymmetric symmetric M-theory backgrounds.
343

Evaluation of Test Data Generation Techniques for String Inputs

Li, Junyang, Xing, Xueer January 2017 (has links)
Context. The effective generation of test data is regarded as very important in the software testing. However, mature and effective techniques for generating string test data have seldom been explored due to the complexity and flexibility in the expression form of the string comparing to other data types. Objectives. Based on this problem, this study is to investigate strengths and limitations of existing string test data generation techniques to support future work for exploring an effective technique to generate string test data. This main goal was achieved via two objectives. First is investigating existing techniques for string test data generation; as well as finding out criteria and Classes-Under-Test (CUTs) used for evaluating the ability of string test generation. Second is to assess representative techniques through comparing effectiveness and efficiency. Methods. For the first objective, we used a systematic mapping study to collect data about existing techniques, criteria, and CUTs. With respect to the second objective, a comparison study was conducted to compare representative techniques selected from the results of systematic mapping study. The data from comparison study was analysed in a quantitative way by using statistical methods. Results. The existing techniques, criteria and CUTs which are related to string test generation were identified. A multidimensional categorisation was proposed to classify existing string test data generation techniques. We selected representative techniques from the search-based method, symbolic execution method, and random generation method of categorisation. Meanwhile, corresponding automated test generation tools including EvoSuite, Symbolic PathFinder (SPF), and Randoop, which achieved representative techniques, were selected to assess through comparing effectiveness and efficiency when applied to 21 CUTs. Conclusions. We concluded that: search-based method has the highest effectiveness and efficiency in three selected solution methods; random generation method has a low efficiency, but has a high fault-detecting ability for some specific CUTs; symbolic execution solution achieved by SPF cannot support string test generation well currently due to possibly incomplete string constraint solver or string generator.
344

\"Branas em supergravidade\" / Branes in supergravity

Leandro Ibiapina Bevilaqua 04 May 2006 (has links)
Este trabalho tem o objetivo de rever a obtenção das soluções do tipo brana em supergravidade e contém uma dedução detalhada das soluções extrema e negra. A fim de motivar algumas escolhas feitas ao longo do cálculo, o trabalho inclui uma breve revisão dos conceitos advindos da teoria de cordas e supersimetria. Esta revisão nos permitirá ainda relacionar as soluções da supergravidade com as branas da teoria de cordas e tecer considerações sobre o papel desta relação na dualidade entre teoria de calibre e gravitação. / This work intends to review the brane solutions of supergravity and contains a datailed deduction of the extremal and black solutions. In order to provide some motivations to the choices through the calculation, this work includes a brief review of some concepts from string theory and supersymmetry. This review will enable us to relate the supergravity solutions to string theory\'s branes and to make considerations about the role of this relationship in the duality between gauge and gravity theories.
345

Teoria de cordas, invariância conforme e simetria BRST / String theory, Conformal invariance and BRST symmetry

Hector Arturo Benitez Del Aguila 31 October 2013 (has links)
O principal objetivo deste trabalho é estudar a quantização covariante da corda bosônica e da supercorda RNS, explorando as simetrias envolvidas, ou seja, as simetrias BRST e conforme no caso da corda bosônica e as generalizações correspondentes para a corda fermiônica. Em particular, discutimos alguns aspectos perturbativos da teoria bosônica e a construção de operadores de vértice da corda fermiônica. / The main goal of this work is to study the covariant quantization of the bosonic and RNS string theories by exploiting the involved symmetries, namely, the BRST and conformal invariance for the bosonic string and the corresponding supersymmetric generalizations for the fermionic case. In particular, we discuss some perturbative aspects of the bosonic theory and the construction of vertex operators for the fermionic string.
346

Uma introdução a supercordas em plano e AdS 5 XS 5 background / An introduction to the superstring in flat and AdS5 X S5 backgrounds

René Negrón Huamán 10 May 2013 (has links)
Apresentamos uma revisão dos elementos básicos do estudo da teoria clássica das supercordas em backgrounds planos e curvos, dando ênfase ao caso importante em que o background e a variedade AdS5 S5. Nós inclumos um estudo da corda bosonica para revisarmos alguns conceitos básicos da teoria de campos conforme em duas dimensões. Em seguida estudamos a teoria das supercordas em um espaço plano onde apresentamos uma introdução pedagógica ao formalismo de espinores puros. A ultima parte e dedicada a generalização da ação de Green-Schwarz para o caso de AdS5 S5 e uma apresentação do modelo sigma do formalismo de espinores puros no mesmo background. / We present a review of the basic elements of the study of classical superstring theory in at and curved backgrounds, giving emphasis to the very important case of the AdS5S5 background. We include a study of the bosonic string to review some basic concepts of two dimensional conformal eld theory. We then move on to the superstring in at space where we present a pedagogical introduction to the pure spinor formalism of superstrings. The last part is devoted to the generalization of the Green-Schwarz action to AdS5 S5 and a presentation of the pure spinor sigma model in the same background.
347

Design and Implementation of a Name Matching Algorithm for Persian Language

Momeninasab, Leila January 2013 (has links)
Name matching plays a vital and crucial role in many applications. They are for example used in information retrieval or deduplication systems to do comparisons among names to match them together or to find the names that refer to identical objects, persons, or companies. Since names in each application are subject to variations and errors that are unavoidable in any system and because of the importance of name matching, so far many algorithms have been developed to handle matching of names. These algorithms consider the name variations that may happen because of spelling, pattern or phonetic modifications. However most existing methods were developed for use with the English language and so cover the characteristics of this language. Up to now no specific one has been designed and implemented for the Persian language. The purpose of this thesis is to present a name matching algorithm for Persian. In this project, after consideration of all major algorithms in this area, we selected one of the basic methods for name matching that we then expanded to make it work particularly well for Persian names. This proposed algorithm, called Persian Edit Distance Algorithm or shortly PEDA, was built based on the characteristics of the Persian language and it compares Persian names with each other on three levels: phonetic similarity, character form similarity and keyboard distance, in order to give more accurate results for Persian names. The algorithm gets Persian names as its input and determines their similarity as a percentage in the output. In this thesis three series of experiments have been accomplished in order to evaluate the proposed algorithm. The f-measure average shows a value of 0.86 for the first series and a value of 0.80 for the second series results. The first series of experiments have been repeated with Levenshtein as well, and have 33.9% false negatives on average while PEDA has a false negative average of 6.4%. The third series of experiments shows that PEDA works well for one edit, two edits and three edits with true positive average values of 99%, 81%, and 69% respectively.
348

Branes and geometry in string and M-theory

Sehmbi, Gurdeep Singh January 2012 (has links)
This thesis is based on two papers by the author and consists of two parts. We review the recent developments in the theory of multiple M2-branes and 3-algebras leading to multiple D2-brane theories. The inclusion of flux terms for the supersymmetric BLG and ABJM theories of closed M2-branes is discussed and then generalised to open M2-branes. Here the boundary condition is derived and different BPS configurations are examined where we find a mass deformed Basu-Harvey equation for the M2-M5 system. The Lorentzian 3-algebra is then employed for obtaining a theory of D2-branes in a flux background, we then obtain the new fuzzy funnel solution of the system of D2-D4 branes in a flux. Matrix theories and their compactifications as well as noncommutative geometry and noncommutative gauge theories are reviewed with a discussion of their generalisations to three dimensions to be used to describe the M-theory three form potential. A new feature of string theory is then obtained called the quantum Nambu geometry (QNG). It is found by considering the action for D1-strings in a RR flux background and we demonstrate that there is a large flux double scaling limit where the action is dominated by a Chern-Simons-Myers coupling term. A classical solution to this is the quantised spacetime known as the quantum Nambu geometry. Various matrix models are obtained from this action, these are the large flux dominated terms of the full actions for the corresponding matrix models. The QNG gives rise to an expansion of D1-strings to D4-branes in the IIA theory, so we obtain an action for the large flux terms for this action which is verified by a dimensional reduction of the PST action describing M5-branes. We make a generalisation of the D4-brane action to describe M5-branes using a duality. We are describing the 3-form self-dual field strength of a non-abelian generalisation of the PST action.
349

Phase Transitions in the Early Universe: The Cosmology of Non-minimal Scalar Sectors

Kost, Jeffrey David, Kost, Jeffrey David January 2017 (has links)
Light scalar fields such as axions and string moduli can play an important role in early-universe cosmology. However, many factors can significantly impact their late-time cosmological abundances. For example, in cases where the potentials for these fields are generated dynamically --- such as during cosmological mass-generating phase transitions --- the duration of the time interval required for these potentials to fully develop can have significant repercussions. Likewise, in scenarios with multiple scalars, mixing amongst the fields can also give rise to an effective timescale that modifies the resulting late-time abundances. Previous studies have focused on the effects of either the first or the second timescale in isolation. In this thesis, by contrast, we examine the new features that arise from the interplay between these two timescales when both mixing and time-dependent phase transitions are introduced together. First, we find that the effects of these timescales can conspire to alter not only the total late-time abundance of the system --- often by many orders of magnitude --- but also its distribution across the different fields. Second, we find that these effects can produce large parametric resonances which render the energy densities of the fields highly sensitive to the degree of mixing as well as the duration of the time interval over which the phase transition unfolds. Finally, we find that these effects can even give rise to a "re-overdamping" phenomenon which causes the total energy density of the system to behave in novel ways that differ from those exhibited by pure dark matter or vacuum energy. All of these features therefore give rise to new possibilities for early-universe phenomenology and cosmological evolution. They also highlight the importance of taking into account the time dependence associated with phase transitions in cosmological settings. In the second part of this thesis, we proceed to study the early-universe cosmology of a Kaluza-Klein (KK) tower of scalar fields in the presence of a mass-generating phase transition, focusing on the time-development of the total tower energy density (or relic abundance) as well as its distribution across the different KK modes. We find that both of these features are extremely sensitive to the details of the phase transition and can behave in a variety of ways significant for late-time cosmology. In particular, we find that the interplay between the temporal properties of the phase transition and the mixing it generates are responsible for both enhancements and suppressions in the late-time abundances, sometimes by many orders of magnitude. We map out the complete model parameter space and determine where traditional analytical approximations are valid and where they fail. In the latter cases we also provide new analytical approximations which successfully model our results. Finally, we apply this machinery to the example of an axion-like field in the bulk, mapping these phenomena over an enlarged axion parameter space that extends beyond those accessible to standard treatments. An important by-product of our analysis is the development of an alternate "UV-based" effective truncation of KK theories which has a number of interesting theoretical properties that distinguish it from the more traditional "IR-based" truncation typically used in the literature.
350

A portfolio of original compositions with a commentary

Nkuna, Musa January 2000 (has links)
This portfolio consists of four diverse original compositions written in 1999 : a string quartet, a cello suite and a set of two choral pieces.

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