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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.
421

Mesoscale activated states gate spiking in the awake brain

Talei Franzesi, Giovanni January 2016 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 109-118). / Neuronal action potentials ('spikes') are thought to be the fundamental units of information in the brain, hence the ability to record them and to understand their genesis is crucial to our comprehension of the biological underpinnings of our thoughts, memories, and feelings. Over the past several decades an extensive body of work has focused on the mechanisms and timescales over which neurons integrate inputs toward spike threshold. However, most of the work has been carried out in vitro or in silico, and our understanding of what underlies the generation of spike patterns in the awake brain has remained limited. Current models emphasize either seconds-scale global states shared by most neurons in a network, or the fast input integration occurring in single neurons over the few milliseconds preceding spiking, but it's not known whether these represent just the extremes of a continuum. Combining a virtual reality environment with an optimized robotic system for intracellular recordings we therefore analyzed the subthreshold dynamics leading to spiking in a variety of network and behavioral states in the hippocampus, a region known to be involved in spatial navigation, learning and memory, as well as in a model neocortical region, the primary somatosensory cortex. We discovered that the majority of spikes are in fact preceded not only by a fast, monotonic rise in voltage over a few milliseconds, consistent with fast input integration within a neuron, but also by a prolonged, gradual (tens to hundreds of ms) depolarization from baseline, which appeared to exert a gating function on subsequent inputs. Unlike the fast voltage rises, these gradual voltage rises are shared across some, but not all, neurons in the network. We propose that the gradual rises in membrane voltage constitute a novel form of activated state, intermediate both in timescale and in what proportion of neurons participate. By gating a neuron's ability to respond to subsequent inputs, these network-mediated intermediate, or mesoscale, activated states could play a key role in phenomena such as cell ensemble formation, gain modulation and selective attention. / by Giovanni Talei Franzesi. / Ph. D.
422

Sartorial robotics

Whiton, Adam (Adam M.) January 2014 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, February 2014. / No formal thesis title-page. Title from abstract page. "September 23, 2013." Cataloged from PDF version of thesis. / Includes bibliographical references (pages 113-119). / Sartorial Robotics is a method of merging fashion theory and robotics through the design and development of robotic systems. These systems facilitate interaction and play as well as mimic the materiality, aesthetics, and construction techniques of textiles, apparel and fashion. This will enhance the social aspects of human-robotic interaction and assist in how we situate robotics in our lives and cultures. Building upon a history of robot aesthetics and a formulaic approach to analyze and understand fashion, a series of design principles for Sartorial Robotics were established and applied in the research and development of robotic systems that utilize the human-centric system of clothing to create robotics for human-robot social interaction. The Group Identity Surface is a soft-architecture system utilizing thermochromic textiles and computer vision to facilitate human-machine teammate building. Zipperbot, a robotic continuous closure for fabric edge joining, was developed to explore autonomous control of a sartorial gesture and performed as a wearable robot which was evaluated through social interactions. Clothing is a uniquely human pursuit and is nearly universal in its adoption and use. It plays a prominent role in our individual cultures transmitting a mixture of social signals and meanings through the semiotics of fashion. It is through this performance of assemblage of fabric surfaces we reconfigure ourselves and our identities. Merging robotics and fashion within the practice of Sartorial Robotics will enhance the explorations of identities for both humans and robots. / Adam Whiton. / Ph. D.
423

SpendView : a platform for democratizing access to government budget and expenditure data / Spend View : a platform for democratizing access to government budget and expenditure data / Platform for democratizing access to government budget and expenditure data

Aristarán, Manuel January 2016 (has links)
Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 76-77). / Budgeting and expenditure data is the clearest expression of a government's priorities. Despite its importance, making it available to the public imposes hard challenges that not every administration is ready to undertake. The lack of IT capabilities and constrained resources of government agencies -regardless of size or budget- make it difficult for them to respond to the demands of information from their constituencies, transparency advocates, the press and central governments. Moreover, these administrations don't usually have access to analysis tools that help them view how the resources are being used and to detect potential risks of misspending -a critical need of elected officials, who are under everyday scrutiny. Responding to these needs, I propose the design, implementation, impact and usability studies of a software platform for analysis and visualization of government budget and expenditure data. / by Manuel Aristarán. / S.M.
424

Reengineering Education : systems engineering and the LearningGraph as a means to develop a coherent learning data architecture / Systems engineering and the LearningGraph as a means to develop a coherent learning data architecture

Groff, Jen January 2018 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018. / Cataloged from PDF version of thesis. Vita. / Includes bibliographical references (pages 179-201). / Today's educational systems are complex, political, sociotechnical ecosystems that struggle to meet the needs of most learners and societal demands-and most critically, struggle to change. Yet, learners globally need access to high quality learning environments and coherent learning pathways that support them to thrive in our complex world. Fundamental to every learning technology, environment, and system, is a learning data model and architecture that helps to organize the learner's experience. To date, in traditional educational systems, this has largely been dominated by public policy curriculum standards, which have tremendous limitations and shortcomings on classroom practice and their ability to support complex learning technologies. At the same time, over the past several decades significant advances have been made in the learning sciences, learning analytics, and learning technologies that have greatly expanded our ability to model learning and provide immersive and adaptive learning environments. Yet each of these communities rarely coordinates and aligns these data models. The disjointedness of these structures leaves their architecture in a messy, challenging state, unable to successfully carry us into an advanced future of learning technologies and effective learning ecosystems. This dissertation explores the use of Systems Engineering as a means to reengineering this critical infrastructure of the system, through the LearningGraph-a research initiative that used this methodology to create a unified data structure for modeling learning constructs in a coherent learning data architecture. The aim of the project is to ultimately inform a new infrastructure to support learning development across learning technologies and environments. In doing so, we create the foundation for closing significant gaps in the current system: between learning sciences research and practice; curriculum and assessment design; the design of learning technologies and all the aforementioned components; and between and across education systems globally. Moreover, it creates the potential for the foundation of a very different future for learning ecosystems. / by Jennifer Sterling Groff. / Ph. D.
425

.art : situating Internet art in the traditional institution for contemporary art / Situating Internet art in the traditional institution for contemporary art

Verschooren, Karen A. (Karen Annemie) January 2007 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Comparative Media Studies, 2007. / Includes bibliographical references (p. 187-202). / This thesis provides a critical analysis of the relation between Internet art and the traditional institution for contemporary art in the North American and West-European regions. Thirteen years after its inception as an art form, the Internet art world finds itself in a developmental stage and its relation to the traditional institution for contemporary art is accordingly. Through an elaborate discussion of the key players, institutions and discourses on aesthetics, economics and exhibition methodologies, this sociological analysis of the past and current situation hopes to offer a solid ground for extrapolation and predictions for Internet art's future as an art world in its relation to the traditional art institutions. / by Karen A. Verschooren. / S.M.
426

Shape changing composite material design for interactions

Yao, Lining January 2017 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 258-274). / This thesis is about designing shape change composite material for interactions. Interaction has gone beyond computer screens and electronics to enter the realm of physical materials. Shape changes at the micro level will cause shape changes and other physical property changes at the macro level. A design strategy for bioinspired shape-changing composite materials includes two development steps: a shape-changing material unit (SCMUnit), followed by a shape-changing matrix composite (SCMC). SCMC contains the matrix phase and the dispersion phase, one of which is composed of SCMUnits. In addition, SCMC can be hierarchical, while SCMC and SCMUnits have a relationship of recursive embodiment. Two major projects exemplify how water-responsive shape-changing material can be used to design interactions based on the outlined design strategy. bioLogic is about hygromorphic bacteria-based SCMC, while Transformative Appetite is about water-driven edible SCMC material. Programmable transformations, multilayer composites and sequential-foldings were engineered with these materials. A customized fabrication strategy, combining wet lab processes and additive manufacturing, was introduced, while applications were presented to exemplify various interaction scenarios. In addition, the SCMC design strategy has been adapted to develop shape-changing materials beyond water responses. Stimuli and responsive behaviors are used to categorize these materials. A design space for nature-inspired responsive material design for shape-changing interfaces was outlined from two aspects: the technical aspects and the conceptual aspects. The technical aspects are identified with the interplays of three features of nature: natural structural mechanisms, natural stimuli and natural transformation mechanisms. The conceptual aspects is summarized in two conceptual spaces: microscale shape changes for macroscale shape changes, and microscale shape changes for macroscale material property changes. / by Lining Yao. / Ph. D.
427

A ceaseless becoming : narratives of adolescence across media

Grigsby, Neal A. (Neal Alan) January 2007 (has links)
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Comparative Media Studies, 2007. / Includes bibliographical references (p. 97-105). / Thesis explores the broad appeal of narratives with adolescent protagonists across a variety of media, including literature, film, and video games. An analysis of key texts within their historical contexts reveals affinities between disparate genres and strong connections between fiction and the discourse of adolescence in psychology, anthropology, and sociology. Adolescence narratives illuminate both the transgressive boundaries of a given culture and the normative center, and make explicit what is usually considered natural or implicit. To discover the roots of contemporary adolescence narratives, prototypes for the picaresque novel, the school story, and the Bildungsroman are examined, and each are shown to contain narrative conventions that survive in recent works. A contemporary case study looks at the trilogy of female coming of age films by Sofia Coppola to show how they embody the ambiguities and contradictions of third wave feminism. Finally, the author explores the affinity between video games and adolescence, the implications of translating literary genres into an interactive medium, and uses examples from both science fiction literature and recent games to theorize how games might better address the themes of adolescence in both story and play mechanics. / by Neal A. Grigsby. / S.M.
428

Modular engineering of neuromuscular gait simulators

Furtney, Matthew D January 2016 (has links)
Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 72-73). / In this thesis we present a novel approach to the computer simulation of forward dynamic gait models and the optimization of parameters that must be tuned for such models. This methodology is not limited to gait simulation, and could be useful for any situation in which a complex Simulink model requires variables to be tuned via machine learning to optimize all heuristic that can only be evaluated via simulation. Through the lens of Biomechatronic engineering research, we combine the fundamentals of software engineering with a refinement of the best practices of Matlab and Simulink programming and a working knowledge of inherent Matlab and Simulink constraints to construct a framework for rapid model development. Key features of this methodology include: the use of Simulink as an environment for rapidly prototyped models, the use of and construction of custom Simulink libraries, and use of the Matlab Optimization Toolbox. This methodology uses parallel evaluation of rapid acceleration Simulink executables to minimize optimization time, and allow research teams to take advantage of parallel processing and cloud computing. This methodology was applied to a bouncing gait model developed by Hartmut Geyer for evaluation. We demonstrate its effectiveness by simulating this model using a custom library of model components, such as ground contact model, Stateflow control, heuristic computation, and body segments. / by Matthew D. Furtney. / S.M.
429

Digital pregnancy through domestic objects : creation of debate around the topic of surrogacy through creation of speculative domestic objects / Creation of debate around the topic of surrogacy through creation of speculative domestic objects

Chen, Dan (Dan Kun-yi) January 2016 (has links)
Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 57-58). / Pregnancy or career - that's a question many women face as they progress with their professional careers. In the high tech industry, driven female professionals often choose to pursue their careers in lieu of having children. For many of them, strategies of surrogacy or freezing eggs are popular options not only because of available technological advancements but also because of shifts in cultural perspective enabled by a new biotechnical regime. The dichotomy that forces an "either-or" divide between motherhood and careership can be seen as a modern form of regulatory control on women. The question of reproduction becomes a matter of our bio-techno-capitalist society as a confine of women's options, voices, and freedom. Companies such as Facebook and Apple have recently offered to pay female employees to freeze their eggs so they can continue with their careers, without interrupting their dreams of having children. In addition, companies in India offer outsourced surrogacy services for U.S. couples who can afford to pay, services that are contingent upon the poverty class that needs additional income. The female employees who are now freezing their eggs in Silicon Valley may very well be choosing this surrogacy option fifteen years down the line. However, there still remains many ethical, social and political dilemmas which exist with surrogacy, questions that must be posed to the public. My thesis intends to inspire those discussions through critical speculative design. Women who choose to delay reproduction to stay in the American capitalistic workforce is an obvious economic advantage for the corporate machine, but are women - both the employees and surrogates - being unethically exploited in this capitalistic arrangement? / by Dan Chen. / S.M.
430

Hybrid body craft

Kao, Hsin-Liu (Hsin-Liu Cindy) January 2018 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 209-223). / Sensor device miniaturization and breakthroughs in novel materials are allowing for the placement of technology increasingly close to our physical bodies. However, unlike all other media, the human body is not simply another surface for enhancement - it is the substance of life, one that encompasses the complexity of individual and social identity. The human body is inseparable from the cultural, the social, and the political, yet technologies for placement on the body have often been developed separately from these considerations, with an emphasis on engineering breakthroughs. This dissertation investigates opportunities for cultural interventions in the development of technologies that move beyond wearable clothing and accessories, and that are purposefully designed to be placed directly on the skin surface. How can we design emerging on-body interfaces to reflect existing cultural practices of decorating the body, with the intent to expand the agency of self-expression? This dissertation looks at this question through the development of a series of research artifacts, and the contextualization of a design space for culturally sensitive design. In this dissertation, Body Craft is defined as existing cultural, historical, and fashion-driven practices and rituals associated with body decoration, ornamentation, and modification. As its name implies, Hybrid Body Craft (HBC) is an attempt to hybridize technology with body craft materials, form factors, and application rituals, with the intention of integrating existing cultural practices with new technological functions that have no prior relationships with the human body. With this grounding, HBC seeks to support the generation of future technologized customs in which technology is integrated into culturally meaningful body adornments. The artifacts in this dissertation encompass the integration of technologies such as flexible electronics, chemical processes, and bio-compatible materials into existing Body Craft customs. These artifacts contribute novel, culturally inspired form factors, and introduce unprecedented interaction modalities for on-body technologies. A design space is created in which to examine shifts in the communicative qualities of these Body Crafts due to the integration of technology, as well as new forms of self-expression that have emerged. This dissertation contributes a culturally sensitive lens to the design of on-body technologies. The intention is to expand their lifetimes and purposes beyond mere novelty and into the realms of cultural customs and traditions. / by Hsin-Liu (Cindy) Kao. / Ph. D.

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