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Ανάλυση συνιστωσών σήματος σε ηλεκτροεγκεφαλογράφημαΓκρούμας, Γεώργιος 13 January 2015 (has links)
Στην παρούσα διπλωματική εργασία γίνεται μελέτη της μεθόδου ανάλυσης ανεξάρτητων συνιστωσών στο ηλεκτροοεγκεφαλογράφημα. Αφού εξετάσουμε το κομμάτι της φυσιολογίας του εγκεφάλου θα δοθεί ένα μαθηματικό υπόβαθρο της ανάλυσης ανεξάρτητων συνιστωσών. Στη συνέχεια θα γίνει μια βιβλιογραφική έρευνα στη σύγκριση αλγορίθμων της ανάλυσης ανεξάρτητων συνιστωσών όταν εφαρμόζονται σε ηλεκτροεγκεφαλογραφήματα με στόχο την βέλτιστη εξαγωγή παρασίτων. Στο τέλος θα γίνει εφαρμογή της μεθόδου της ανάλυσης ανεξάρτητων συνιστωσών σε πραγματικά δεδομένα ηλεκτροεγκεφαλογραφήματος 64 καναλιών μέσω του περιβάλλοντος του Matlab. Στόχος της εφαρμογής αυτής είναι ο διαχωρισμός των ανεξάρτητων συνιστωσών μη-εγκεφαλικής προέλευσης και η αφαίρεση τους από τα αρχικά δεδομένα. / This thesis is a study of the independent componenet analysis in electroencephalogram. After looking at the piece of brain physiology we will give a mathematical framework of independent component analysis. Then it will become a literature search in the comparison algorithms of Independent Component Analysis in EEGs when applied with a view to optimal extraction of artifacts. At the end will be the method of independent component analysis to real EEG data 64 channels through the environment of Matlab. The aim of this application is the separation of independent components of non brain activity and removing them from the original data.
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Surface Electromyography of the Pelvic Floor Musculature: Reliability and Validity of a Novel Electrode DesignKeshwani, Nadia 07 February 2011 (has links)
Purpose: Intravaginal probes used for recording electromyography (EMG) from the pelvic floor muscles (PFMs) likely record activity from nearby muscles (crosstalk), and move during functional tasks, causing motion artifact data contamination, threatening the validity of results obtained. This study investigated the test-retest reliability and validity of surface EMG recordings from the PFMs using a novel, theoretically superior electrode in comparison to a commercially available intravaginal probe, the FemiscanTM. Methods: Healthy subjects (n=20) performed tasks with each vaginal electrode in situ: i) PFM maximal voluntary contractions (MVC), ii) coughs, iii) unilateral hip adductor/external rotator contractions at 25%MVC, 50%MVC, and MVC while keeping the PFMs relaxed or maximally contracted, and iv) transversus abdominis contractions (TrA; recorded using fine-wires) at 25%MVC, 50%MVC, MVC.
Analyses: i) Intraclass correlation coefficients (ICC), ii) t-tests of proportions (α=0.05), iii) repeated measures ANOVAs and Tukey’s post-hoc testing (α=0.05) and iv) cross-correlation functions between peaks of transversus abdominis and PFM activity were used to determine the between-trial and between-day reliability of each vaginal electrode, a difference in prevalence of motion artifact contamination between electrodes, and the presence of crosstalk from the hip and TrA, respectively.
Results: Between-trial reliability of both vaginal electrodes was excellent (ICC(3,1)=0.943-0.974). Between-day reliability was less consistent (ICC(3,1)=0.788-0.924 and 0.648-0.715 for the FemiscanTM and novel electrode, respectively). No significant difference in the proportion of files contaminated with motion artifact using each electrode existed. At submaximal intensities of hip muscle contractions, the FemiscanTM recorded significantly higher EMG amplitudes compared to what it recorded when the hip was relaxed, whereas the novel electrode did not, indicating that the FemiscanTM recorded crosstalk from the hip musculature. Low cross-correlation coefficients (<0.90) and large time delays (≥ 0.5 milliseconds) between peaks of PFM and TrA activity indicated that neither vaginal electrode recorded crosstalk from the TrA.
Conclusion: The novel electrode is a promising tool to record EMG from the PFMs, as it records less crosstalk from the hip musculature than current technology while maintaining a high degree of reliability when comparing results collected within the same session; however, this electrode should not be used to compare one’s muscle activity between days. / Thesis (Master, Rehabilitation Science) -- Queen's University, 2011-02-07 14:46:30.811
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Characterization of Evoked Potentials During Deep Brain Stimulation in the ThalamusKent, Alexander Rafael January 2013 (has links)
<p>Deep brain stimulation (DBS) is an established surgical therapy for movement disorders. The mechanisms of action of DBS remain unclear, and selection of stimulation parameters is a clinical challenge and can result in sub-optimal outcomes. Closed-loop DBS systems would use a feedback control signal for automatic adjustment of DBS parameters and improved therapeutic effectiveness. We hypothesized that evoked compound action potentials (ECAPs), generated by activated neurons in the vicinity of the stimulating electrode, would reveal the type and spatial extent of neural activation, as well as provide signatures of clinical effectiveness. The objective of this dissertation was to record and characterize the ECAP during DBS to determine its suitability as a feedback signal in closed-loop systems. The ECAP was investigated using computer simulation and <italic>in vivo</italic> experiments, including the first preclinical and clinical ECAP recordings made from the same DBS electrode implanted for stimulation. </p><p>First, we developed DBS-ECAP recording instrumentation to reduce the stimulus artifact and enable high fidelity measurements of the ECAP at short latency. <italic>In vitro</italic> and <italic>in vivo</italic> validation experiments demonstrated the capability of the instrumentation to suppress the stimulus artifact, increase amplifier gain, and reduce distortion of short latency ECAP signals.</p><p>Second, we characterized ECAPs measured during thalamic DBS across stimulation parameters in anesthetized cats, and determined the neural origin of the ECAP using pharmacological interventions and a computer-based biophysical model of a thalamic network. This model simulated the ECAP response generated by a population of thalamic neurons, calculated ECAPs similar to experimental recordings, and indicated the relative contribution from different types of neural elements to the composite ECAP. Signal energy of the ECAP increased with DBS amplitude or pulse width, reflecting an increased extent of activation. Shorter latency, primary ECAP phases were generated by direct excitation of neural elements, whereas longer latency, secondary phases were generated by post-synaptic activation.</p><p>Third, intraoperative studies were conducted in human subjects with thalamic DBS for tremor, and the ECAP and tremor responses were measured across stimulation parameters. ECAP recording was technically challenging due to the presence of a wide range of stimulus artifact magnitudes across subjects, and an electrical circuit equivalent model and finite element method model both suggested that glial encapsulation around the DBS electrode increased the artifact size. Nevertheless, high fidelity ECAPs were recorded from acutely and chronically implanted DBS electrodes, and the energy of ECAP phases was correlated with changes in tremor. </p><p>Fourth, we used a computational model to understand how electrode design parameters influenced neural recording. Reducing the diameter or length of recording contacts increased the magnitude of single-unit responses, led to greater spatial sensitivity, and changed the relative contribution from local cells or passing axons. The effect of diameter or contact length varied across phases of population ECAPs, but ECAP signal energy increased with greater contact spacing, due to changes in the spatial sensitivity of the contacts. In addition, the signal increased with glial encapsulation in the peri-electrode space, decreased with local edema, and was unaffected by the physical presence of the highly conductive recording contacts.</p><p>It is feasible to record ECAP signals during DBS, and the correlation between ECAP characteristics and tremor suggests that this signal could be used in closed-loop DBS. This was demonstrated by implementation in simulation of a closed-loop system, in which a proportional-integral-derivative (PID) controller automatically adjusted DBS parameters to obtain a target ECAP energy value, and modified parameters in response to disturbances. The ECAP also provided insight into neural activation during DBS, with the dominant contribution to clinical ECAPs derived from excited cerebellothalamic fibers, suggesting that activation of these fibers is critical for DBS therapy.</p> / Dissertation
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The Impact of Environment on Building IT Technical CompetencyWierwille, Benjamin Joseph 01 May 2012 (has links)
Information Technology Technical Competency is critical for the optimal functioning of any organization. IT personnel need to be competent in their technical skills. Studying how IT personnel build their technical competencies is a critical but under-studied area of research. To date, very little research has been done on how to build IT Technical Competencies, and virtually none of this research begins with qualitative data or uses IT personnel as key respondents. Initially, we evoke a revealed causal map that shows four concepts in the IT Environment construct: the Technical Environment, the People Environment, the Business Environment, and the Job Environment. Our model first proposes a relationship between the IT Environment and IT Technical Competency. An original survey based on the qualitative data was developed for this study. Data was collected at four research sites: a manufacturing organization, a healthcare organization, a government organization, and an education organization. All together 101 respondent's survey answers were analyzed. We tested the proposed model of IT Technical Competency using the method of path analysis with linear regression. Our results indicated that the Technical and Business Environments are viewed as one, so we end up with a three environment concept model of IT Technical Competency. Our model achieved a R-squared value of above 0.5, meaning that the environment surrounding IT personnel, the IT Environment, is 50% related to IT Technical Competency. This is the first model to this author's knowledge that holistically looks at environment in relation to technical competency. Future research will continue look more in-depth at each of the concepts in this environment individually.
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"Using Design to Make the Home Whole": Meaning and the Model Home-Arizona in the 1950sJanuary 2013 (has links)
abstract: Scholars have written much about home and meaning, yet they have said little about the professionally furnished model home viewed as a cultural artifact. Nor is there literature addressing how the home building industry uses these spaces to promote images of family life to increase sales. This research notes that not only do the structure, design, and layout of the model home formulate cultural identity but also the furnishings and materials within. Together, the model home and carefully selected artifacts placed therein help to express specific chosen lifestyles as that the home builder determines. This thesis considers the model home as constructed as well as builder's publications, descriptions, and advertisements. The research recognizes the many facets of merchandising, consumerism, and commercialism influencing the design and architecture of the suburban home. Historians of visual and cultural studies often investigate these issues as separate components. By contrast, this thesis offers an integrated framework of inquiry, drawing upon such disciplines as cultural history, anthropology, and material culture. The research methodology employs two forms of content analysis - image and text. The study analyzes 36 model homes built in Phoenix, Arizona, during the period 1955-1956. The thesis explores how the builder sends a message, i.e. images, ideals, and aspirations, to the potential home buyer through the design and decoration of the model home. It then speculates how the home buyer responds to those messages. The symbiotic relationship between the sender and receiver, together, tells a story about the Phoenix lifestyle and the domestic ideals of the 1950s. Builders sent messages surrounding convenience, spaciousness, added luxury, and indoor-outdoor living to a growing and discriminating home buying market. / Dissertation/Thesis / M.S.D. Design 2013
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A invisível luz que projeta a sombra do agora: gênero, artefato e epistemologias na arte contemporânea brasileira de autoria negra / The invisible art that projects the shadow of now: genre, artifact and epistemologies in the contemporary brazilian art of black authorshipJanaina Barros Silva Viana 23 August 2018 (has links)
Nesta pesquisa propõe-se o debate sobre aspectos da experimentação em artes visuais pautado no papel do autor e nos discursos traçados pelas relações de identidade e alteridade na arte contemporânea. O retorno à ideia do artista como autor e a individualização dos critérios artísticos ao longo do século XX e XXI tornam-se fundamentais para discutir visualidades em busca de redefinições a respeito das formas de protagonismos no cenário artístico como é o caso de produções associadas diretamente ao epíteto arte afro-brasileira, no sentido em que se refere a produções múltiplas em temas, linguagens, discursos e estratégias de leituras. Traça-se um breve panorama sobre uma cena de autoria negra e seus trânsitos em espaços institucionais nas últimas décadas. Além de apresentar um recorte que considera a leitura da própria pesquisa poética visual. Tem-se como interesse, refletir sobre a construção de epistemologias a partir do debate de gênero e artefato na arte contemporânea. Assim, destacam-se nesta discussão os trabalhos de Rosana Paulino, Sonia Gomes e Lidia Lisboa. O artefato aparece nesta escrita como performance e método: escrita contranarrativa, memória e gesto político. Apresenta a problemática nos lugares de fricção em relação às terminologias instauradas, às condutas poéticas e éticas na arte contemporânea e suas epistemologias. Qual a relevância em sinalizar a origem étnica de uma autoria numa dada forma poética dentro de um contexto histórico e político? Quais movimentos na confuguração de um discurso visual implicam na construção de uma leitura sobre gênero? Quais gestos operativos sinalizam essa condição? De qual maneira nós construímos os nossos olhares e nossas perspectivas nesta encruzilhada sobre a ideia de histórias pessoais e universalidades, microestruturas e macroestruturas? Quando estas autorias falam por si? Qual o lugar possível de legitimidade delas? Quais são as estratégias possíveis de reescritas de contranarrativas? / In this research is proposed a discussion about aspects of experimentation in the visual arts based on the role of the author and in the discourses traced by the relations of identity and otherness in contemporary art. The return to the idea of the artist as na author and the individualization of the artistic criteria along the XX and XXI century become fundamental to discuss the visualities in search of redefinitions about the forms of prominences in the artistic scene as is the case of the productions associated directly to the epithet Afro-Brazilian art, referring to a multiple authorship and its transits in institutional spaces in the last decades is presented. Besides to presenting a clipping that considers the Reading of the own poetic visual research. We have as na interest, to reflect on the construction of epistemologies from the debate of genre and artifact in contemporary art. Thus, the work of Rosana Paulino, Sonia Gomes and Lidia Lisboa stands out in this discussion. The artifact appears in this writing as a performance and method: the counternarrative writing, memory and political motion. It presentes the problematic in the places of epistemologies. What is the relevance of signal the ethnic origino f na author in a certain poetic form within a historical and political contexto? Which movements in the configuration of a visual discourse imply in the construction of a Reading abourt genre? What operative gestures signal this condition? How do we constructo our views and our perspectives at this crossroads about the idea of personal histories and universals, microstructures and macro-structures? When do these authors speak for themselves? What is their possible place of legitimacy? What are the possible rewriting strategies of conter-narratives?
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Joalheria, arte ou design?VIDELA, Ana Neuza Botelho 08 April 2016 (has links)
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Previous issue date: 2016-04-08 / A proposta do estudo visou comparar duas formas de fazer joalheria, uma mais próxima dos paradigmas da arte e outra com um viés mais comercial para, dessa
forma, entender os processos que condicionam a atuação dos produtores das duas categorias. Neste sentido, o objetivo da pesquisa foi identificar em quais
circunstâncias a joalheria é considerada arte, por ser uma categoria orientada para a produção de trabalhos mais experimentais, os quais podem ter a intenção de
problematizar a ornamentação corporal ou a linguagem da joalheria ou, ao contrário, em que contexto é compreendido como uma atividade fruto do processo de design,
adotando, porém, os pressupostos da joalheria para atender ao mercado. Do ponto de vista metodológico, distinguir as características dos produtos gerados a partir da
influência dos dois campos de atuação implicou no acompanhamento das práticas de produção, comercialização, eventos de divulgação dos segmentos e lançamentos
de coleções, tanto das joias produzidas por designers de joias, quanto das joias produzidas por artistas joalheiros. A construção teórica da pesquisa objetivou
abarcar o ponto de vista do sujeito e seu contexto, além da agência do objeto resultante da formação de coletivos produtores de joias. O estudo também abarcou
a reflexão sobre corpo artefatual, não só em referência a um corpo fabricado, mas no intuito de entender o corpo como feito por artefatos. Neste sentido, a obra de
Bruno Latour serviu como ferramenta para se pensar o corpo como constitutivamente sendo feito a partir da composição dos atores humano e atores
não-humanos. Assim, um dos aspectos que se discute são as redes entre sujeitos e seus objetos. Como resultados, observamos que os joalheiros, por se situarem entre
os dois campos de práticas, parecem se encontrar em um espaço liminar. De um lado, afirmam que o que os diferenciam das outras formas de produzir joalheria é a
exploração ou experimentação do objeto associado ao corpo, o qual é dotado de intencionalidade, ao manifestar o pensamento de quem o fez. De outro lado, têm-se
os produtores que se identificam com o campo do design, para quem todos os aspectos do comércio joalheiro devem estar cuidadosamente em consonância com a
proposta do produto. / The purpose of the study was to compare two ways to make jewelry, one closer of art paradigms and the other with a more commercial bias to thus understand the
processes that affect the way producers of the two categories act. In this sense, the objective of the research was to identify under what circumstances jewelry is
considered art for being a category targeted on production of more experimental works, which may be intended to problematize the body ornamentation or the jewelry
language or, otherwise, in which context is understood as a result of an activity design process, adopting, however, the jewelry assumptions to meet the market.
From a methodological point of view, distinguishing the characteristics of products generated by the influence of the two fields of activity, involved the monitoring of
production practices, marketing, dissemination events of the segments and collections launches of both the jewelry produced by jewelry designers, as the
jewelry produced by artists jewelers. The theoretical construction of the research aimed to encompass the subject's point of view and its context, in addition to the
object's agency resulting of the formation of jewelry producers collectives. The study also encompassed reflection on artifactual body, not only in reference to a
manufactured body, but in order to understand the body as made by artifacts. n this sense, the work of Bruno Latour served as a tool for thinking about the body as
constitutively made from the composition of human actors and non-human actors. Thus, one of the aspects discussed are the networks between subjects and their
objects. As results, we noticed that jewelers, because they are located between the two camps practices, seem to find themselves in a liminal space. On one hand, they
claim that what differentiate them from other forms of producing jewelry is the exploration or experimentation of the object associated with the body, which is
endowed with intentionality, to express the thought of who did it. On the other hand, there are the producers who identify themselves with the design field, for whom all
aspects of the jewelry trade must be carefully in line with the proposal of the product.
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Porto do Sal: um espaço híbrido entre Belém e a paisagem insular amazônica / Porto do Sal: a hybrid space between Belém and the insular amazonian landscapeElisa Arruda Kunz 11 September 2017 (has links)
Nesta dissertação ocorre a investigação sobre o espaço Porto do Sal (Belém/PA) e a paisagem material encontrada no lugar. Há a suposição de uma interferência do espaço insular amazônico sobre o Porto do Sal, devido aos acessos frequentes a este espaço estimulados pela atividade econômica do Porto, por meio de barcos. A pergunta fundamental se refere a descobrir quais elementos construtivos encontrados na paisagem do Porto revelam indícios de uma interferência do ambiente insular. O objetivo geral é a aproximação com o Porto do Sol, a ponto de obter um panorama amplo do seu modo de construir, que se desdobra desde a arquitetura das habitações até os artefatos. De modo específico está a busca pelo conhecimento do ambiente insular, seja por entradas presenciais nesse espaço, seja pelo amparo em autores que o investigaram; realizar aproximação etnográfica no Porto do Sal, para entendimento dos motivos que se revelam na ação construtiva deste lugar; analisar um grupo de autores que discutam os assuntos relacionados ao estudo, sendo eles: ARRUDA (2014), ISABELLE (2011), SANTOS (1996), JACQUES (2007), CERTEAU (2014), TUAN (1983), LOUREIRO (1995), dentre outros. Para o registro da paisagem do Porto do Sal, foram utilizados o diário de campo e fotografia da paisagem. Estão presentes no lugar elementos peculiares ao espaço insular amazônico - hábitos, modos de agir, falar, vestir, construir, habitar - e isto é demonstrado nos capítulos de discussão teórica e também por meio da organização de um panorama visual presente no \'Percurso imagético entre a Amazônia insular e o Porto do Sal - livro-relato da paisagem em estudo\', que encerra o volume. O sujeito amazônico, seus hábitos e as manifestações culturais que o envolvem são discutidos e mostrados ao longo do estudo, assim como o rebatimento desse contexto no Porto do Sal, que configura este lugar como o ponto de encontro entre as ilhas amazônicas e Belém, um reservatório da expressão do ambiente insular diluído pela cidade grande em contato. / In this dissertation we investigate the space of Porto do Sal (Belém/PA) and the material landscape found there. There is the assumption of an interference of the Amazonian insular space over Porto do Sal, dueto the frequent accesses to this space stimulated by the economic activity ofthe port, by means ofboats. The fundamental issue is related to the discovery of which constructive elements found in the landscape of Porto do Sal reveal evidences of an interference from the insular environment. The general objective is to promote an approximation with Porto do Sal, in order to obtain a wide panorama of its construction, which unfolds from the architecture of the dwellings to the artifacts. Specifically, the knowledge of the insular environment is sought, either by presence in that space or by the support of authors who investigated it; as well as performing an ethnographic approach with Porto do Sal, in order to understand the reasons that are revealed in the constructive action ofthis place; and analyzing a group of authors that discuss the subjects related to the study, such as: ARRUDA (2014), ISABELLE (2011), SANTOS (1996), JACQUES (2007), CERTEAU (2014), TUAN (1983), LOUREIRO (1995), among others. To record the landscape of Porto do Sal, the field diary and landscape photography were used. The elements peculiar to the Amazonian island space present in this place - habits, ways of acting, talking, dressing, building, inhabiting - are demonstrated in the theoretical discussion chapters and also through the organization of a visual panorama present in \'Percurso imagético entre a Amazônia insular e o Porto do Sal - livro-relato da paisagem em estudo\', which closes the volume. The amazonian subject, his habits and the cultural manifestations that surround him are discussed and shown throughout the study, as well as the projection of this context in Porto do Sal, which configures this place, like a meeting point between the Amazonian islands and Belém, as a reservoir of the expression of the insular environment diluted by the big city in contact.
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”Out of sight, out of mind” : En studie av svenska bokbloggares inställningar till e-boken / ”Out of sight, out of mind” : A study of Swedish book bloggers attitudes towards the ebookZaar, Oskar, Sörlin, Anton January 2014 (has links)
There are experiential products that through a digital transformation wholly or partially have taken new place in our everyday lives. Just a few years ago, we had music on CDs, movies on tape and books in bookshelves. In Sweden, we are now facing a transformation when the e-book begins to take place alongside the printed book. This paper focuses on what values play a role in the attitude towards ebooks among a selected group of Swedish book bloggers. A qualitative content analysis was performed on blog posts concerning the ebook from twelve different Swedish book blogs. The posts were then coded into categories and values. We found five broad categories in which value was displayed; Ownership, Availability, Price, Ergonomics and Environment. These could in turn be linked to two basic ways to give value to ebooks and reading, through its Utilitarian and Experiential value. The findings suggest that Availability was the one most important to the bloggers. We also found that most posts took place within two discourses - Technology Dissatisfaction and Technology Fear. Technology Dissatisfaction was more frequent and strongly linked to the construction of the e-book and the technical systems that are available today.
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Reverse Architecting / Reverse ArchitectingSun, Gang January 2005 (has links)
Architecture is a key factor to the success of the software product, but at least the state of art is not the state of practice. The connection between the completed system and the architecture has often been damaged after the original implementation. Reverse architecting is a method to recover the software architecture by analyzing the artifact. Since reverse architecting is not mature yet, the paper studies methods, tools, and major issues which hinder the person performing reverse architecting all together from knowing whether the reverse architecting method is repeatable and possible to apply on the different releases of the same product.
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