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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.
1

The development of resilience - a model

Maginness, Alison January 2007 (has links)
The impetus for this study grew from observations in clinical practice that many individuals survived all sorts of hardships with minimal distress, or with the ability to tolerate their distress, and move on with their lives in a positive manner. A review of the literature led to the conclusions that the research investigating resilience was making minimal inroads into understanding what made these people different, and that the richness of who they were was being lost in the scientific process. This dissatisfaction led to the decision to explore the construct from a phenomenological framework, and to try and discover the essential elements of resilience through analysis of the subjective experience of resilience. A qualitative study involving thirteen participants identified by their peers as resilient was undertaken and the underlying themes of their stories were analysed. This led to the development of a model of resilience that attempted to balance the need for parsimony with that of explanatory breadth, and which had the potential to tolerate the complexity and instability of the construct itself. The model developed identified three core elements that embraced the construct of resilience. These included the physiological capacity to be resilient, and from this basis the ability to be adaptive and the ability to maintain well-being emerge. Factors identified with these elements include individual reactivity to and recovery from adverse events, the ability to be effective and efficient in the management of adverse events, and the beliefs about the world and the self that promote well-being when exposed to adverse events. The model has a basis within neurobiology and is framed within the context of Dynamic Systems Theory. The theory itself is a culmination of clinical observations with what is known from within the current literature and the results of this study.
2

Closing the developmental loop on the behavioral and neural dynamics of flexible rule-use

Buss, Aaron Thomas 01 December 2013 (has links)
Executive function (EF) is a central aspect of cognition that undergoes significant changes in early childhood. Changes in EF in early childhood are robustly predictive of academic achievement and general quality of life measures later in adulthood. I develop a dynamic neural field (DNF) model which provides a process-based account of behavior and developmental change in a key task used to probe the early development of executive function--the Dimensional Change Card Sort (DCCS) task. In the DCCS, children must flexibly switch from sorting cards either by shape or color to sorting by the other dimension. Typically, 3-year-olds, but not 5-year-olds, lack the flexibility to do so and perseverate on the first set of rules when instructed to switch. In Study 1, I use the DNF model to integrate behavioral and neural processes by simulating hemodynamics associated with the early emergence of flexible rule-use. I then test predictions of the model using near-infrared spectroscopy. In Study 2, I develop a DCCS that can be used with adults that sheds light on key aspects of the task as they have been revealed with children. Using fMRI, a pattern of behavioral and neural effects shed light on the central processes involved in flexible rule-use. These two studies demonstrate that performance emerges as a property of system-wide interactions and that common neurocognitive effects .can be found between childhood and adulthood.
3

The development of resilience - a model

Maginness, Alison January 2007 (has links)
The impetus for this study grew from observations in clinical practice that many individuals survived all sorts of hardships with minimal distress, or with the ability to tolerate their distress, and move on with their lives in a positive manner. A review of the literature led to the conclusions that the research investigating resilience was making minimal inroads into understanding what made these people different, and that the richness of who they were was being lost in the scientific process. This dissatisfaction led to the decision to explore the construct from a phenomenological framework, and to try and discover the essential elements of resilience through analysis of the subjective experience of resilience. A qualitative study involving thirteen participants identified by their peers as resilient was undertaken and the underlying themes of their stories were analysed. This led to the development of a model of resilience that attempted to balance the need for parsimony with that of explanatory breadth, and which had the potential to tolerate the complexity and instability of the construct itself. The model developed identified three core elements that embraced the construct of resilience. These included the physiological capacity to be resilient, and from this basis the ability to be adaptive and the ability to maintain well-being emerge. Factors identified with these elements include individual reactivity to and recovery from adverse events, the ability to be effective and efficient in the management of adverse events, and the beliefs about the world and the self that promote well-being when exposed to adverse events. The model has a basis within neurobiology and is framed within the context of Dynamic Systems Theory. The theory itself is a culmination of clinical observations with what is known from within the current literature and the results of this study.
4

Stochastic Block Model Dynamics

Nithish Kumar Kumar (10725294) 29 April 2021 (has links)
<div>The past few years have seen an increasing focus on fairness and the long-term impact of algorithmic decision making in the context of Machine learning, Artificial Intelligence and other disciplines. In this thesis, we model hiring processes in enterprises and organizations using dynamic mechanism design. Using a stochastic block model to simulate the workings of a hiring process, we study fairness and long-term evolution in the system. </div><div> </div><div> We first present multiple results on a deterministic variant of our model including convergence and an accurate approximate solution describing the state of the deterministic variant after any time period has elapsed. Using the differential equation method, it can be shown that this deterministic variant is in turn an accurate approximation of the evolution of our stochastic block model with high probability.</div><div> </div><div> Finally, we derive upper and lower bounds on the expected state at each time step, and further show that in the limiting case of the long-term, these upper and lower bounds themselves converge to the state evolution of the deterministic system. These results offer conclusions on the long-term behavior of our model, thereby allowing reasoning on how fairness in organizations could be achieved. We conclude that without sufficient, systematic incentives, under-represented groups will wane out from organizations over time.</div>
5

The Meaning of Life: A Merleau-Pontian Investigation of How Living Bodies Make Sense

Moss Brender, Noah January 2012 (has links)
Thesis advisor: Jeffrey Bloechl / This dissertation takes up Maurice Merleau-Ponty's unfinished project of developing an ontology of nature whose concepts are drawn from the phenomenon of life, rather than from human techne. I argue that the question of life has been hopelessly obscured by the collapse, in the Modern era, of the distinction between nature and artifice. We cannot hope to understand the difference between life and non-life until we understand the difference between the living body and the machine. Merleau-Ponty's constant aim was to show that the living body is not a blind mechanism, and that the body has its own endogenous sense which is not projected onto it by a disembodied consciousness. Central to these efforts were the phenomena of learning and development, and the concept of form or Gestalt. Development is what distinguishes the living body, which is an open-ended process of becoming, from the machine, whose possibilities are determined in advance by its creator. In order to conceptualize the phenomenon of development, Merleau-Ponty appropriated from psychology the concept of form (Gestalt): a dynamic, self-organizing whole that cannot be decomposed into independent parts. Where the conception of nature as mechanism implies that everything is determined in advance, Merleau-Ponty's conception of nature as Gestalt allows for the genesis of genuinely new phenomena through nature's own self- organizing movement. We would thus be able to understand the genesis of sense in nature as a process of morphogenesis--the genesis of form. However, Merleau-Ponty struggled to clarify the ontological status of form. He lacked the conceptual resources to explain form in its own terms, rather than by contrast with the decomposable wholes of human artifice. This dissertation attempts to locate these conceptual resources in the science of complexity that has emerged since Merleau- Ponty's death, and whose descriptions of complex systems are uncannily anticipated in Merleau-Ponty's writings. I take from this new science the conception of form as asymmetry or difference, and of morphogenesis as symmetry-breaking or self-differentiation. In order to investigate how meaning emerges out of form, I turn to recent work in biology and psychology that applies the concept of symmetry-breaking to the phenomena of anatomical growth and motor development. By studying the development of the living body and its behavior, I show how nature articulates itself into perceiver and perceived. In the movement of the living body, form folds back upon itself, giving rise to a new kind of meaning: a pre-reflective, motor significance that is neither mechanism nor mental representation. In Chapter One, I distinguish the living body from a machine or artifact by distinguishing between manufacturing and growth. This distinction, which seemed obvious to the Ancients, has been obscured by Modern science's pivotal decision to treat nature as if it were a product of human artifice. This decision has committed us to an atomistic ontology, which takes nature to be a synthetic whole composed of mutually indifferent parts. However, this ontology faces a basic problem, which I call the problem of form: how to explain the synthesis of indifferent atoms into the complex, harmonious wholes we observe in nature, without appealing to an intelligent designer. Nowhere is this problem more acute than in the phenomenon of anatomical development or embryogenesis. I argue that biology has been unable to explain this phenomenon in mechanical or atomistic terms: the Neo-Darwinist view of the living body as a synthetic whole determined in advance by a genetic blueprint or program has succeeded not by explaining development, but rather by ignoring it. In Chapter Two, I argue that the problem of form--and of living form in particular--can only be resolved by abandoning our atomistic ontology, and with it our synthetic understanding of form as a shape imposed on an indifferent material. Recent developments in the science of complexity have yielded a new definition of form as asymmetry or difference. On this view, the genesis of form in nature is not the synthesis of wholes out of pre-existing parts, but the self-differentiation of wholes into parts through symmetry-breaking. In order to understand how natural wholes become less symmetrical over time, I introduce three further concepts from the science of complexity: nonlinearity, stability, and instability. With these concepts in hand, I return to the problem of embryogenesis, in order to show how complex living forms can develop reliably and robustly without being determined in advance by a design or program. In Chapter Three, I turn from anatomical development to the development of behavior, in order to see how the genesis of form becomes a genesis of sense. I begin by criticizing three mechanistic theories of behavior--Behaviorism, Cognitivism, and Connectionism--which suffer from the same problem of form that plagues mechanistic theories of anatomical development. Behavior grows like an organ: by symmetry-breaking, not by synthesis. Learning is not a matter of association, but of differentiation: the perception of increasingly subtle asymmetries in the body's environment through increasingly asymmetrical movements. It is the world that teaches the organism how to move--but a world that is only revealed to the organism by its own movements. Thus the living body and its world grow together dialectically, each driving the other to become more determinate through its own increasing determinacy. / Thesis (PhD) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Philosophy.
6

Dynamic intertextuality and emergent second language microdevelopment in digital space

Deifell, Elizabeth Dryman 01 August 2018 (has links)
This naturalistic exploratory multiple case study of the academic writing activity of L2 writers enrolled in an introductory Spanish literature course reveals the complex dynamicity of intertextual activity and L2 development. The writing tasks, designed for communicative practice rather than for mastery of a genre, required students to upload Microsoft Word documents to the learning management software’s dropbox, thus necessitating their engagement with multiple digitally mediated resources. Participants completed the assignment outside of class in a computer lab, where data were collected, including observational field notes, screen recordings, and stimulated recall, and semi-structured interviews about the participants’ use and perception of digital resources. Findings show that these students employed many strategies with a variety of resources, including online dictionaries, translators, and original and translated texts, when experiencing a lexical gap while writing. A close examination of second language writers’ intertextual engagement with the affordances provided by these digitally mediated resources through an analytical frame informed by dynamic systems theory (Larsen-Freeman & Cameron, 2008a) reveals idiosyncratic use and evidence of emergent word and strategy learning. Pedagogical implications, including the need to start where students are, are discussed.
7

Embodying Social Practice: Dynamically Co-Constituting Social Agency

Dunst, Brian W. 01 January 2013 (has links)
Theories of cognition and theories of social practices and institutions have often each separately acknowledged the relevance of the other; but seldom have there been consistent and sustained attempts to synthesize these two areas within one explanatory framework. This is precisely what my dissertation aims to remedy. I propose that certain recent developments and themes in philosophy of mind and cognitive science, when understood in the right way, can explain the emergence and dynamics of social practices and institutions. Likewise, the view I construct explains how social practices and institutions shape the character of cognition of their constituent agents. Moreover, I explain both cognitive and social agency under the single explanatory framework provided by Dynamic Systems Theory. Drawing upon the phenomenological tradition, "embodied, "extended", "embedded", "enactive", and "ecological" approaches to cognition, as well as the conceptual resources of Dynamic Systems Theory, I construct a theory of agency that sees cognitive and social agents as far-from-equilibrium, open, recursively self-maintenant dynamic systems. Depending on the specifics of concrete circumstances, such systems, which I call "Dynamic Embodied Agents" (or DEAs), may develop and possess emergent capacities for error-detection, flexible learning, normative behavior, representation, self-reflection, various modes of pattern-recognition, a temporal sense of self, and even moral responsibility. Some such systems are also sensitive to perceived social influences (practices and institutions); while reciprocally constituting and causally affecting them.
8

Emergence of comprehension of Spanish second language requests

Sauveur, Robert Paul 23 October 2013 (has links)
This dissertation examines the developmental trajectory of online processing toward second language (L2) pragmatic comprehension. This goal stems from two shortcomings of previous research: (1) approaching L2 pragmatics as the acquisition of discrete phenomena through progressive stages (see Kasper, 2009), and (2) focusing narrowly on production. Building upon previous L2 pragmatic comprehension work (Carrell, 1981; P. García, 2004; Taguchi, 2005, 2007, 2008a, 2008b, 2011a, 2011b; Takahashi & Roitblat, 1994), the current study investigates the development of L2 Spanish request speech act comprehension by native English-speaking adult learners. The analysis involves accuracy, comprehension speed and the relationship between the two dimensions across three levels of directness over a 13-week period. Previous research was informed by skill acquisition theories (Anderson & Lebiere, 1998) to account for increased accuracy and decreased speed over time. Here, further analysis is based on Complexity Theory / Dynamic Systems Theory (CT/DST) (Larsen-Freeman, 1997; Larsen-Freeman & Cameron, 2008a; de Bot, Lowie, & Verspoor, 2007; Ellis, et al., 2009; Verspoor, de Bot, & Lowie, 2011) to account for the seemingly chaotic results often found in L2 research. The findings of the current study show significant overall improvement in accuracy and speed of Spanish request identification, and a moderate relationship between the two measures. However, the association between slower responses and higher accuracy in the current data contradicts skill acquisition theories. Rather, the theoretical framework of CT/DST provides a more authentic account of development. As such, the results indicate that the levels of request directness develop along distinct trajectories and timescales. Direct requests reflect higher accuracy and faster interpretation. While the most indirect level of requests shows the largest improvement in accuracy, the responses for these items are no faster at the end of the study than at the beginning. The development of conventionally indirect requests occupies a middle ground in terms of accuracy similar to direct requests and comprehension speed like implied items. Further findings reflect L2 pragmatic comprehension as a complex, dynamic system that emerges through the differential effects of predictor variables across measures and within sub-groups of participants based on proficiency improvement, motivation and response strategy. / text
9

<b>FEEDING DEVELOPMENT IN THE CONTEXT OF INFANT VOCALIZATIONS & CAREGIVER FEEDING RESPONSIVENESS</b>

Rachel Hahn Arkenberg (14058693), Georgia A Malandraki (13552066), Amanda Seidl (14322469), Katherine C. Hustad (10233005), Kameron Moding (11647538), Amy L. Delaney (11609163), Allison J. Schaser (9317679) 17 April 2024 (has links)
<p dir="ltr">The development of feeding skills is essential for infant health, growth, and family well-being. Despite the importance of this skill, relatively little is known about the development of independent solid feeding skills relative to other body systems – like vocalizations – or external factors including caregivers or the feeding environment. The purpose of this preliminary study was to examine the relationship between feeding skills, vocalizations, and caregiver feeding responsiveness at the same point in 6-8-month-old infants. We conducted this study remotely in order to obtain the most accurate assessment of infant skills and include diverse infant feeding experiences within their own home environments. Twenty-five typically developing – low-risk – infants and a pilot group of ten infants at increased risk for feeding and communication disorders completed the study, along with their caregivers. Infants were categorized as “at-risk” if they spent time in the Neonatal Intensive Care Unit. We collected feeding data through caregiver-recorded videos of typical mealtimes, vocalization measures from daylong audio recordings, and responsiveness assessments from video-conferencing interviews with caregivers and the mealtime feeding videos. In our sample, it was feasible to use these remote data collection methods, and we obtained high inter- and intra-rater reliability for all measures (> 90%). In our preliminary study, we found that infants in the low- and at-risk groups demonstrated different oral motor feeding skills. In hierarchical regression models, the interaction between risk group and utterance duration was the most significant predictor of oral motor feeding skills, while neither vocalization measure was strongly related to eating efficiency. In the opposite direction, feeding skills were not predictive of either normalized child vocalization count or utterance duration. Relative to caregiver feeding responsiveness, we found that caregiver feeding responsivity alone did not predict feeding or vocalization measures. Responsivity in combination with weeks of feeding experience and medical risk group was related to oral motor feeding skill but not related to vocalization measures. Overall, this study provided initial evidence that feeding skills develop as a dynamic system, influenced by multiple within-child and external factors, and future research is warranted on the influence of these factors on feeding and communication skill development.</p>
10

Design Strategies for Low Thrust Transfers in the Earth-Moon System

Liam Vincent Fahey (20284386) 18 November 2024 (has links)
<p dir="ltr">The increased interest in deep space missions is creating an increased interest in cislunar space. The need for fast and efficient methods of traversing the lunar vicinity in creases as more spacecraft enter the region. This investigation discusses methods of low thrust transfer design in order to create low cost and low time of flight transfers. Indirect optimization is employed to compute minimum energy and minimum fuel transfers in the circular restricted three body problem. Sigmoid smoothing techniques are leveraged to ap proximate the optimal bang-coast-bang solution with continuous functions. The minimum fuel solution is employed as an initial guess to target an inertially fixed thrust direction transfer. This process is applied to a variety of cislunar orbital transfer problems. Transfers are constructed between orbits in the L1 halo, L2 halo, distant retrograde, and L4 short period orbit families. The resulting trajectories are compared to impulsive and free transfers from the literature based on the required propellant mass and time of flight.</p>

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