Dynamical Systems Theory (DST) (De Bot, Lowie, & Vespoor 2007; Larsen-Freeman 1997, 2007; Larsen-Freeman & Cameron 2008; Dörnyei 2009; and van Lier 2000) represents a scientific paradigm shift derived from the fields of physics, engineering and theoretical mathematics that attempts to solve real-world scenarios that do not respond to scientific reductionism, otherwise known as ‘analysis’. The purpose of this dissertation is to (re)frame foreign language learning/use as a dynamical process that that involves interplay among what Dörnyei (2009) terms the language, the agent and the environment. More specifically, this dissertation presents a quasi-experimental, psycholinguistic study that looks at the interface between language (in this case the talk that resulted from NS-NNS interactions) and agent (as defined by a set of personal traits, or Individual Differences [IDs], including motivation, attitudes, personality and aptitude) in order to answer the research question: Do IDs vary in conjunction with language learning/use, and if so, how? Eight tutored Spanish learners were followed over the course of 16 weeks during which time they participated in 8 chat sessions with a native Spanish-speaker. Their ID profiles were measured immediately before and after each session and sessions with significant pre- to post-session ID shifts were analyzed to determine to what extent such shifts correlated with certain types of talk and/or think-aloud sequences. Results indicated that all participants’ pre- and post-interactional ID profiles fluctuated measurably and significantly, even within the span of a single interaction. Moreover, those sessions with significantly positive ID shifts were qualitatively different in terms of language-related episodes (LREs), conversation management/pragmatic markers, and metacognition from those with significantly negative ID shifts. Other unexpected findings revealed, for example, that LREs (especially NS-initiated LREs) negatively impacted motivations and attitudes and, therefore, the language-learning process itself. Taken together, the results of this study indicate that the agent’s IDs and their (inter)language co-emerge; that is to say, they evolve simultaneously and in response to one another. Moreover, this study suggests that DST can indeed be quasi-experimentally applied to the study of SLA, thus necessitating further development in DST-oriented methodologies and research questions. / text

abstract: In response to the recent publication and media coverage of several books that support educating boys and girls separately, more public schools in the United States are beginning to offer same-sex schooling options. Indeed, students may be more comfortable interacting solely with same-sex peers, as boys and girls often have difficulty in their interactions with each other; however, given that boys and girls often interact beyond the classroom, researchers must discover why boys and girls suffer difficult other-sex interactions and determine what can be done to improve them. We present two studies aimed at examining such processes. Both studies were conducted from a dynamical systems perspective that highlights the role of variability in dyadic social interactions to capture temporal changes in interpersonal coordination. The first focused on the utility of applying dynamics to the study of same- and mixed-sex interactions and examined the relation of the quality of those interactions to participants' perceptions of their interaction partners. The second study was an extension of the first, examining how dynamical dyadic coordination affected students' self-perceived abilities and beliefs in science, with the intention of examining social predictors of girls' and women's under-representation in science, technology, engineering, and mathematics. / Dissertation/Thesis / Ph.D. Family and Human Development 2012

Orientador: Luiz Antonio Barreira San Martin / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Científica / Made available in DSpace on 2018-08-08T04:52:24Z (GMT). No. of bitstreams: 1 Alves_LucianaAparecida_M.pdf: 720915 bytes, checksum: 31e0287aff59267244e774856c7d82af (MD5) Previous issue date: 2007 / Resumo: O principal objetivo desta dissertação é fornecer condições para garantirmos a existencia dos expoentes de Lyapunov. Inicialmente, introduzimos o conceito de expoente de Lyapunov associado a sistemas de equaçoes diferenciais lineares não autonomas e discutimos algumas propriedades que surgem com a introduçao deste conceito. Em seguida, damos duas versoes para a demonstraçao do Teorema Ergodico Multiplicativo de Oseledec para fluxos em tempo discreto associados a cociclos definidos sobre fibrados vetoriais triviais. A partir disto, estendemos este teorema para sistemas em tempo continuo, usando a extensao do Teorema Ergodico Subaditivo de Kingman. Finalmente, apresentamos uma noçao de fluxos em fibrados mais gerais do que fibrados triviais e obtemos, sob determinadas condiçoes, um caso particular do Teorema de Oseledec em cada fibra de um fibrado vetorial nao-trivial / Abstract: The main result of this work provides conditions to assure the existence of Lyapunov exponents. First of all, we introduce the concept of Lyapunov exponents associated to nonautonomous linear differential equations and we discuss some properties which appear with the introduction of this concept. We give two versions for the proof of Oseledec¿s Multiplicative Ergodic Theorem for discrete time flows associated to cocycles which are defined in trivial vector bundles. From this, we extend this theorem for continuos time systems, using an extension of Kingman¿s Subadditive Ergodic Theorem. Finally, we present a notion of flows in fiber bundles more general than the trivial vector bundles and we obtain, given some conditions, a particular case of the Oseledec¿s Theorem in each fiber of a non trivial vector bundle / Mestrado / Sistemas Dinamicos / Mestre em Matemática

No description available.

Coulomb forces acting between close flying charged spacecraft provide near zero propellant relative motion control, albeit with added nonlinear coupling and limited controllability. This novel concept has numerous potential applications, but also many technical challenges. In this dissertation, two- and three-craft Coulomb formations near GEO are investigated, using a rotating Hill frame dynamical model, that includes Debye shielding and differential gravity. Aspects of dynamical systems theory and optimization are applied, for insights regarding stability, and how inherent nonlinear complexities may be beneficially exploited to maintain and maneuver these electrostatic formations. Periodic relative orbits of two spacecraft, enabled by open-loop charge functions, are derived for the first time. These represent a desired extension to more substantially studied, constant charge, static Coulomb formations. An integral of motion is derived for the Hill frame model, and then applied in eliminating otherwise plausible periodic solutions. Stability of orbit families are evaluated using Floquet theory, and asymptotic stability is shown unattainable analytically. Weak stability boundary dynamics arise upon adding Coulomb forces to the relative motion problem, and therefore invariant manifolds are considered, in part, to more efficiently realize formation shape changes. A methodology to formulate and solve two-craft static Coulomb formation reconfigurations, as parameter optimization problems with minimum inertial thrust, is demonstrated. Manifolds are sought to achieve discontinuous transfers, which are then differentially corrected using charge variations and impulsive thrusting. Two nonlinear programming algorithms, gradient and stochastic, are employed as solvers and their performances are compared. Necessary and sufficient existence criteria are derived for three-craft collinear Coulomb formations, and a stability analysis is performed for the resulting discrete equilibrium cases. Each specified configuration is enabled by non-unique charge values, and so a method to compute minimum power solutions is outlined. Certain equilibrium cases are proven maintainable using only charge control, and feedback stabilized simulations demonstrate this. Practical scenarios for extending the optimal reconfiguration method are also discussed. Lastly, particular Hill frame model trajectories are integrated in an inertial frame with primary perturbations and interpolated Debye length variations. This validates qualitative stability properties, reveals particular periodic solutions to exhibit nonlinear boundedness, and illustrates higher-fidelity solution accuracies. / text

Orientadores: Mário Jorge Dias Carneiro, Marco Antonio Teixeira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-19T10:54:43Z (GMT). No. of bitstreams: 1 Damasceno_JosueGeraldo_D.pdf: 1045427 bytes, checksum: 2cb1e5f51924e8667d69ad7267aeaa4e (MD5) Previous issue date: 2011 / Resumo: Descrevemos algumas propriedades dinâmicas de uma família de aplicações bilhares sobre curvas convexas (ovais) as quais são deformadas pelo fluxo de curvatura. Quando a mesa se deforma, a razão entre as curvaturas mínima e máxima converge a 1 e por um resultado clássico de Gage e Hamilton, depois de uma normalização, as curvas tendem a um círculo. Como conseqüência, a região de Lazutkin, isto é, a região que contém cáusticas convexas, cresce gradualmente. Descreveremos algumas bifurcações dinâmicas nesse processo, em particular, descreveremos o que acontece com a família de órbitas de período dois e as órbitas "zig-zag" / Abstract: We describe some dynamical properties of one parameter families of billiards on convex curves (ovals) which are deformed by the curvature flow. As the billiard table deforms, the ratio between minimal and maximal curvature converges to 1 and by a classical result of Gage and Hamilton [GH], after a normalization, the curves tend to a circle. As a consequence, the Lazutkin region, i.e. the region that contains convex caustics, gradually increases. We describe some dynamical bifurcations in this process, in particular, we describe what happens with the family of period two orbits and the "zig-zag"orbits / Doutorado / Matematica / Doutor em Matemática

<div>Over the past twenty years, ridesharing opportunities for smallsats, i.e., secondary payloads, has increased with the introduction of Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) rings. However, the orbits available for these secondary payloads is limited to Low Earth Orbits (LEO) or Geostationary Orbits (GEO). By incorporating a propulsion system, propulsive ESPA rings offer the capability to transport a secondary payload, or a collection of payloads, to regions beyond GEO. In this investigation, the ridesharing scenario includes a secondary payload in a dropped-off Geosynchronous Transfer Orbit (GTO) and the region of interest is the vicinity near the Sun-Earth Lagrange points. However, mission design for secondary payloads faces certain challenges. A significant mission constraint for a secondary payload is the drop-off orbit orientation, as it is dependent on the primary mission. To address this mission constraint, strategies leveraging dynamical structures within the Circular Restricted Three-Body Problem (CRTBP) are implemented to construct efficient and flexible transfers from GTO to orbits near Sun-Earth Lagrange points. First, single-maneuver ballistic transfers are constructed from a range of GTO departure orientations. The ballistic transfer utilize trajectories within the stable manifold structure associated with periodic and quasi-periodic orbits near the Sun-Earth L1 and L2 points. Numerical differential corrections and continuation methods are leveraged to create families of ballistic transfers. A collection of direct ballistic transfers are generated that correspond to a region of GTO departure locations. Additional communications constraints, based on the Solar Exclusion Zone and the Earth’s penumbra shadow region, are included in the catalog of ballistic transfers. An integral-type path condition is derived and included throughout the differential corrections process to maintain transfers outside the required communications restrictions. The ballistic transfers computed in the CRTBP are easily transitioned to the higher-fidelity ephemeris model and validated, i.e., their geometries persist in the ephemeris model. To construct transfers to specific orbits near Sun-Earth L1 or L2, families of two-maneuver transfers are generated over a range of GTO departure locations. The two-maneuver transfers consist of a maneuver at the GTO departure location and a Deep Space Maneuver (DSM) along the trajectory. Families of two-maneuver transfers are created via a multiple- shooting differential corrections method and a continuation process. The generated families of transfers aid in the rapid generation of initial guesses for optimized transfer solutions over a range of GTO departure locations. Optimized multiple-maneuver transfers into halo and Lissajous orbits near Sun-Earth L1 and L2 are included in this analysis in both the CRTBP model and the higher-fidelity ephemeris model. Furthermore, the two-maneuver transfer strategy employed in this analysis are easily extended to other Three-Body systems. </div>

Esta pesquisa de doutorado investiga a transição do balbucio às primeiras palavras, tendo como intuito verificar se há continuidade entre os dois tipos de produção e identificar os templates. A perspectiva teórica assumida é a dos Sistemas Dinâmicos (THELEN; SMITH, 1994), que prevê mudança, instabilidade, variabilidade e não linearidade, ao longo do desenvolvimento. O termo sistemas dinâmicos, na forma mais genérica, significa sistemas de elementos que mudam ao longo do tempo (THELEN; SMITH, 2006, p. 258). A proposta fonológica da Whole-Word/Templatic Phonology é assumida na análise dos dados infantis. O aspecto inovador desta tese está na discussão a respeito da (des)continuidade ao analisar dados de transição para identificação de templates, isto é, a emergência de padrões sistemáticos que facilitam a expansão do léxico (VIHMAN; VELLEMAN, 2000). Além disso, é também inovador o uso do método quantitativo para a identificação de templates ao longo do desenvolvimento fonológico, pois a literatura tem realizado até o momento estudos qualitativos (VIHMAN; VELLEMAN, 2002; VIHMAN; CROFT, 2007; KEREN-PORTNOY et al., 2008; WAUQUIER; YAMAGUCHI; 2012; KHATTAB; AL-TAMINI, 2012; SZREDER, 2012, entre outros). Assim, o presente trabalho contribui para os estudos a respeito do desenvolvimento fonológico, pois apresenta um estudo quantitativo para identificação de templates, busca a relação entre a emergência deles e a transição do balbucio às primeiras palavras, mapeando a ordem e uso de templates ao longo do desenvolvimento fonológico das crianças. Na análise da transição do balbucio às primeiras palavras, são analisados dados do português brasileiro (PB) de três crianças (M, A e G), no período compreendido entre 9 meses e 2 anos. Na análise, são identificados momentos de instabilidade, o que está de acordo com o que é defendido pelos estudos dinâmicos (THELEN; SMITH, 1994; KELSO, 1995), os quais enfatizam o caráter não linear e instável do desenvolvimento. No que se refere à discussão a 8 respeito da (des)continuidade entre os dois tipos de produção, a comparação da análise fonológica conduzida nos dois períodos traz complicações para a hipótese da continuidade. Embora se observe a sobreposição entre os dois tipos de produção, são identificadas mais diferenças do que semelhanças entre as produções balbuciadas e de palavras. Conclui-se que é equivocado defender uma visão a favor da continuidade assumindo que um módulo fonológico age independentemente do fonético. A continuidade só pode ser atestada se for assumida uma perspectiva que defenda a integração dos dois módulos, como, por exemplo, a Fonologia Articulatória/Gestual (BROWMAN; GOLDSTEIN, 1986; ALBANO, 2001) ou a Fonologia de Uso/Teoria dos Exemplares (CRISTÓFARO-SILVA, 2003). Os resultados mostram que, embora as crianças caminhem para pontos comuns da fonologia da língua-alvo, por exemplo, tamanho de palavra, estrutura silábica, entre outros, diferenças são encontradas no que se refere à transição, às estratégias usadas para expansão do léxico, isto é, uso de diferentes templates, e à ordem de uso e desuso de tais estratégias. Em suma, os momentos de auto-organização do sistema fonológico de cada criança tendem a diferir. / This thesis investigates the transition from babble to first words in order to verify if there is continuity between the periods and identify templates. This work follows the theoretical approach to the study of development Dynamic Systems Theory (THELEN; SMITH, 1994; Kelso, 1995) and its view that the development is characterized by change, instability, variability and non linearity. The term dynamical systems, in its most generic form, means systems of elements that change over time (THELEN; SMITH, 2006, p. 258). The Whole- Word/Templatic Phonology approach is followed in the analysis of child data (VIHMAN; VELLEMAN, 2002; VIHMAN; CROFT, 2007; KEREN-PORTNOY et al., 2008). The innovative aspect of this thesis is that it relates the (des)continuity in the transition from babble to words to templates, i.e., systematic shapes that facilitate expansion of the lexicon (VIHMAN; VELLEMAN, 2000). Furthermore, this research uses quantitative method for the identification of templates. The previous literature used only qualitative methods of data collection (VIHMAN; VELLEMAN, 2002; VIHMAN; CROFT, 2007; KEREN-PORTNOY et al., 2008; WAUQUIER; YAMAGUCHI; 2012; KHATTAB; AL-TAMINI, 2012; SZREDER, 2012, among others). Thus, this research contributes by presenting a quantitative study and by observing templates behaviour through early phonological development. Data from three children aged 9 24 months are analysed. In the analysis, non linearity and instability are observed in the phonological development. In regard to the discussion on (des)continuity, the results do not present many evidences in favour of continuity. Although babble and words are produced in the same session, the two types of production show more phonological differences than similarities. The conclusion is that continuity between babble and words cannot be verified if it is assumed that phonological and phonetic aspects work independently from one another. The continuity can 10 be verified if these two modules are integrated as Articulatory /Gestural Phonology (BROWMAN; GOLDSTEIN, 1986; ALBANO, 2001) and Usage- Based Phonology/Exemplar Theory (CRISTÓFARO-SILVA, 2003) propose. The results show that different children produce similar phonological structures in their phonological development, e.g., word length, syllable structure, among others; which follow the characteristics of the target language. However, differences are found in the transition from babble to words in relation to the strategies used for lexical expansion, i.e., the use of different templates as the order of use and disuse of templates. This study observes that moments of self-organization tend to vary from child to child in the development of phonology.

Esta pesquisa de doutorado investiga a transição do balbucio às primeiras palavras, tendo como intuito verificar se há continuidade entre os dois tipos de produção e identificar os templates. A perspectiva teórica assumida é a dos Sistemas Dinâmicos (THELEN; SMITH, 1994), que prevê mudança, instabilidade, variabilidade e não linearidade, ao longo do desenvolvimento. O termo sistemas dinâmicos, na forma mais genérica, significa sistemas de elementos que mudam ao longo do tempo (THELEN; SMITH, 2006, p. 258). A proposta fonológica da Whole-Word/Templatic Phonology é assumida na análise dos dados infantis. O aspecto inovador desta tese está na discussão a respeito da (des)continuidade ao analisar dados de transição para identificação de templates, isto é, a emergência de padrões sistemáticos que facilitam a expansão do léxico (VIHMAN; VELLEMAN, 2000). Além disso, é também inovador o uso do método quantitativo para a identificação de templates ao longo do desenvolvimento fonológico, pois a literatura tem realizado até o momento estudos qualitativos (VIHMAN; VELLEMAN, 2002; VIHMAN; CROFT, 2007; KEREN-PORTNOY et al., 2008; WAUQUIER; YAMAGUCHI; 2012; KHATTAB; AL-TAMINI, 2012; SZREDER, 2012, entre outros). Assim, o presente trabalho contribui para os estudos a respeito do desenvolvimento fonológico, pois apresenta um estudo quantitativo para identificação de templates, busca a relação entre a emergência deles e a transição do balbucio às primeiras palavras, mapeando a ordem e uso de templates ao longo do desenvolvimento fonológico das crianças. Na análise da transição do balbucio às primeiras palavras, são analisados dados do português brasileiro (PB) de três crianças (M, A e G), no período compreendido entre 9 meses e 2 anos. Na análise, são identificados momentos de instabilidade, o que está de acordo com o que é defendido pelos estudos dinâmicos (THELEN; SMITH, 1994; KELSO, 1995), os quais enfatizam o caráter não linear e instável do desenvolvimento. No que se refere à discussão a 8 respeito da (des)continuidade entre os dois tipos de produção, a comparação da análise fonológica conduzida nos dois períodos traz complicações para a hipótese da continuidade. Embora se observe a sobreposição entre os dois tipos de produção, são identificadas mais diferenças do que semelhanças entre as produções balbuciadas e de palavras. Conclui-se que é equivocado defender uma visão a favor da continuidade assumindo que um módulo fonológico age independentemente do fonético. A continuidade só pode ser atestada se for assumida uma perspectiva que defenda a integração dos dois módulos, como, por exemplo, a Fonologia Articulatória/Gestual (BROWMAN; GOLDSTEIN, 1986; ALBANO, 2001) ou a Fonologia de Uso/Teoria dos Exemplares (CRISTÓFARO-SILVA, 2003). Os resultados mostram que, embora as crianças caminhem para pontos comuns da fonologia da língua-alvo, por exemplo, tamanho de palavra, estrutura silábica, entre outros, diferenças são encontradas no que se refere à transição, às estratégias usadas para expansão do léxico, isto é, uso de diferentes templates, e à ordem de uso e desuso de tais estratégias. Em suma, os momentos de auto-organização do sistema fonológico de cada criança tendem a diferir. / This thesis investigates the transition from babble to first words in order to verify if there is continuity between the periods and identify templates. This work follows the theoretical approach to the study of development Dynamic Systems Theory (THELEN; SMITH, 1994; Kelso, 1995) and its view that the development is characterized by change, instability, variability and non linearity. The term dynamical systems, in its most generic form, means systems of elements that change over time (THELEN; SMITH, 2006, p. 258). The Whole- Word/Templatic Phonology approach is followed in the analysis of child data (VIHMAN; VELLEMAN, 2002; VIHMAN; CROFT, 2007; KEREN-PORTNOY et al., 2008). The innovative aspect of this thesis is that it relates the (des)continuity in the transition from babble to words to templates, i.e., systematic shapes that facilitate expansion of the lexicon (VIHMAN; VELLEMAN, 2000). Furthermore, this research uses quantitative method for the identification of templates. The previous literature used only qualitative methods of data collection (VIHMAN; VELLEMAN, 2002; VIHMAN; CROFT, 2007; KEREN-PORTNOY et al., 2008; WAUQUIER; YAMAGUCHI; 2012; KHATTAB; AL-TAMINI, 2012; SZREDER, 2012, among others). Thus, this research contributes by presenting a quantitative study and by observing templates behaviour through early phonological development. Data from three children aged 9 24 months are analysed. In the analysis, non linearity and instability are observed in the phonological development. In regard to the discussion on (des)continuity, the results do not present many evidences in favour of continuity. Although babble and words are produced in the same session, the two types of production show more phonological differences than similarities. The conclusion is that continuity between babble and words cannot be verified if it is assumed that phonological and phonetic aspects work independently from one another. The continuity can 10 be verified if these two modules are integrated as Articulatory /Gestural Phonology (BROWMAN; GOLDSTEIN, 1986; ALBANO, 2001) and Usage- Based Phonology/Exemplar Theory (CRISTÓFARO-SILVA, 2003) propose. The results show that different children produce similar phonological structures in their phonological development, e.g., word length, syllable structure, among others; which follow the characteristics of the target language. However, differences are found in the transition from babble to words in relation to the strategies used for lexical expansion, i.e., the use of different templates as the order of use and disuse of templates. This study observes that moments of self-organization tend to vary from child to child in the development of phonology.

Behavioural scientists argue that ‘social learning' provides the link between biological phenomena and cultural phenomena because of its role in the ‘cultural transmission' of knowledge among individuals within and across generations. However, leading authors within the social sciences have proposed alternative ways of thinking about social life not founded on the Modern oppositions including nature-culture, biology-culture, body-mind, and individual-society. Similarly, the distinction between a domain of nature and a domain of nurture has also been extensively criticized within biology. Finally, advocates of ‘radical embodied cognitive science' offer an alternative to the representational-computational view of the mind which supports the conventional notion of culture and cultural information. This thesis attempts to integrate developmental systems theory, radical embodied cognitive science, and relational thinking, with the goal to bring the field of social learning closer to these critical theoretical developments. In Chapter 2, I find no justification for the claim that the genome carries information in the sense of specification of biological form. Chapter 3 presents a view of ontogeny as a historical, relational, constructive and contingent process. Chapter 4 uses the notions of environmental information, abilities, affordances, and intentions to make sense of behaviour and learning. In Chapter 5, I argue that the notion of social learning can be understood in terms of relational histories of development rather than in terms of transmission of information. I then report empirical studies investigating behavioural coordination and social learning consistent with this theoretical framework. Chapter 6 presents evidence that dyads in a joint making activity synchronize their attention constrained by their changing situation and that coordination of attention is predictive of implicit and explicit learning. Chapter 7 presents evidence that joint attention does not require gaze following and that attentional coordination is predictive of learning a manual task. Together, these theoretical and empirical studies suggest a new way of thinking about how humans and other animals live and learn socially, one that is consistent with critical theoretical and philosophical developments that are currently neglected in the literature on social learning.