Made available in DSpace on 2014-06-12T18:08:23Z (GMT). No. of bitstreams: 2 arquivo9473_1.pdf: 920450 bytes, checksum: 8de41a22d93f1f66a4f3481b45626f98 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2012 / Devido a maior oferta de petróleos pesados e alto grau de contaminantes que os derivados deste possuem, os processos de hidrorrefino têm recebido atenção especial ao longo dos últimos por possibilitar a remoção de contaminantes e melhorar a margem de lucro das refinarias por tonar possível a obtenção de derivados de maior valor agregado. Entre esses o processo de hidrotratamento (HDT), no qual ocorre uma série de reações que utilizam o gás hidrogênio como reagente, foi o foco de estudo deste trabalho. Ao ser aplicado em correntes de Diesel o HDT realiza a remoção de contaminantes como enxofre e nitrogênio, aumentando a qualidade do mesmo. A unidade de HDT tem como principal equipamento o reator, que consiste em um leito com partículas sólidas, onde gás e líquido escoam em fluxo co-corrente ou em contracorrente. Apesar deste processo já ser maduro, o crescente aumento nas exigências de mercado demandam por melhorias no mesmo, a fim de atingir uma rentabilidade cada vez maior. Desta forma o uso de inferenciadores na estimação das variáveis tornaria possível o melhor acompanhamento do processo como também a implementação de novas estratégias de controle. Visto a relevância desse tema o presente trabalho abordou o desenvolvimento de observadores de estado para o reator do processo de HDT, para isto foi necessário a aquisição de dados do processo, o que foi conseguido através de um modelo matemático do reator, o qual foi denominado como planta virtual. Esta forneceu os dados para treinamento e validação dos inferenciadores aqui estudados: as redes neuronais e a neuro-fuzzy. No decorrer do trabalho foi definido o tempo de amostragem e o período de excitação do sinal através da menor constante de tempo. Para treinamento dos inferenciadores foi utilizado dois bancos de dados distintos, um com tempo de amostragem de 50s, onde este foi obtido pelo método da constante de tempo, e outro com amostragem de 10 minutos, em que as seguintes variáveis foram inferenciadas: concentração de compostos sulfurados, nitrogenados e olefinas na saída do reator. Dessas o melhor resultado foi obtido na inferência da concentração de compostos sulfurados realizada através da Rede Neuronal. Foi escolhida esta rede neuronal na implementação de um controlador PID e como modelo interno de um controlador NNMPC. O controlador PID cuja variável de controle foi à concentração de sulfurados foi chamado de controlador PID inferencial e os resultados deste se mostraram melhores do que os resultados obtidos pelo controlador NNMPC

Robots should offer a human-like level of dexterity when handling objects if humans are to be replaced in dangerous and uncertain working environments. This level of dexterity for human-like manipulation must come from both the hardware, and the control. Exact replication of human-like degrees of freedom in mobility for anthropomorphic robotic hands are seen in bulky, costly, fully actuated solutions, while machine learning to apply some level of human-like dexterity in underacted solutions is unable to be applied to a various array of objects. This thesis presents experimental and theoretical contributions of a novel neuro-fuzzy control method for dextrous human grasping based on grasp synergies using a Human Computer Interface glove and upgraded haptic-enabled anthropomorphic Ring Ada dexterous robotic hand. Experimental results proved the efficiency of the proposed Adaptive Neuro-Fuzzy Inference Systems to grasp objects with high levels of accuracy.

The focus of this thesis was to measure the intracellular voltage of a living neural cell using a silicon transistor. The coupling of neurological tissues with silicon devices is of interest to the fields of neurology, neuroscience, electrophysiology and cellular biology. In previous work by Peter Fromherz, single neurons were successfully coupled to transistors [1]. This thesis aims to show proof of concept of the fabrication of a simple neuro-silicon interface using wafer processing methods currently available at Cal Poly. The types of transistors and cells used, the methods for dissecting and preparing the cells, the electrophysiology methods for validating the experiments, and portions of the design of the junction were based on Fromherz’s 1991 work. Other aspects were revised to be compatible with technologies available at Cal Poly. Leech Retzius cells were isolated and cultured from Hirudo Medicinalis and joined to the gate oxide of a P-channel field effect transistor using SU-8 photoresist wells treated with poly-l-lysine. Transistors were operated in strong inversion and source-drain currentfluctuations were observed that correlated with action potentials of the current clamped Retzius cell. Further work is needed to develop better junctions that can reliably couple action potentials. This work lays a foundation for neuro-silicon interface fabrication at Cal Poly.

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This dissertation investigates the turn of the century fascination with synesthesia and efforts by Modernist artists and writers to produce cross-modal works that attempt to defy sensory boundaries. Works of impossible art are artistic and literary experiments with style and form that develop out of the realism and naturalism of the nineteenth century, to be sure; they are also conceived of by their creators as scientific experiments that test what is possible at the limits of perception. Accordingly, while my work is situated within the field of aesthetics, I take a neuroscientific approach to aid in understanding the modes of perception these works are attempting to explore. My project applies the findings of recent neuroscientific studies into clinical synesthesia as a guide for thinking about these Modernist works. The methodology of neuro-aesthetics allows me to develop a theory of sensory mimesis. Sensory mimesis is a holistic approach to explaining phenomenological experience that depends on a sensory semantics, more fundamental and more comprehensive than a linguistic semantics, that I propose filters our access to the world. What we ultimately learn from impossible art is that the range of neurodiversity in humans is broader than we tend acknowledge or appreciate. The notoriously indefinable and uncategorizable character of queer theory is an applicable framework to match the innumerable neurocognitive possibilities that are actually available. To this end, my dissertation suggests that a shift to a neuro-queer-aesthetic paradigm would not only expand human perceptive possibilities, but also enable compassionate engagement within and among our diverse communities. / English

No description available.

Les mesures de plasticité synaptique ont historiquement impliqué l'utilisation de méthodes d'électrophysiologie qui, en intégrant les nombreux influx synaptiques, offrent une très grande sensibilité de détection de changements de forces synaptiques. Cette grande sensibilité se fait cependant aux dépens d'une information spatiale quant à la localisation des synapses subissant une plasticité. Sachant que la plasticité synaptique est un phénomène qui peut être indépendant d'une synapse à l'autre, il devient important d'avoir la possibilité de mesurer, à l'échelle synaptique, les changements moléculaires associés à cette plasticité. De nouveaux outils fluorescents développés dans les dernières décennies permettent maintenant de visualiser directement l'activité synaptique, la signalisation et le remodelage à l'échelle synaptique. Durant ma maîtrise en biophotonique, j'ai mesuré optiquement l'activité calcique résultant d'une libération spontanée de neurotransmetteurs à l'aide d'un nouveau senseur de calcium (Ca2+) génétiquement encodé, GCaMP6f. Pour ce faire, j'ai imagé par vidéo-microscopie des neurones d'hippocampes de rats en culture perfusés avec une solution sans Mg2+ contenant de la Tetrodotoxine (0Mg/TTX). J'ai observé, dans des compartiments dendritiques et dans des épines, des oscillations transitoires et localisées du Ca2+ intracellulaire, nommées influx synaptiques miniatures de Ca2+ (MSCTs). Afin de tester la possibilité de potentialiser les MSCTs, je les ai enregistrés avant et après un protocole de stimulation de 5 minutes reconnu pour induire une plasticité synaptique dans les neurones en culture (0Mg2+/Glycine/Bicuculline, cLTP). J'ai observé qu'une augmentation de la fréquence et de l'amplitude des MSCTs, pouvant persister parfois jusqu'à une heure, est induite par le protocole de stimulation. J'ai donc tenté d'identifier les mécanismes moléculaires de cette plasticité. Les MSCTs sont principalement générés par l'ouverture des récepteurs NMDA, car ils sont presque totalement bloqués par l'addition d'AP5, un antagoniste sélectif au récepteur. De plus, l'ajout d'AP5 durant le protocole de stimulation bloque la plasticité. Il semble donc que les MSCTs et leur plasticité sont dépendants des récepteurs NMDA. Fait intéressant, ni les MSCTs ni leur plasticité ne sont bloqués par le NBQX, un antagoniste des récepteurs AMPA, ce qui laisse supposer que la plasticité résulte possiblement de changements dans la quantité et la composition des récepteurs NMDA, en plus des modifications dans la signalisation du Ca2+ et dans la régulation de la libération de neurotransmetteurs. Également, alors que nous avons observé que l'activité enzymatique de la CaMKII n'est pas essentielle pour l'induction et l'expression de la plasticité, certains résultats préliminaires démontrent un possible rôle de la PKA. Afin de tester mes diverses hypothèses, j'ai également combiné l'imagerie de Ca2+ avec l'imagerie d'autres composants pré et postsynaptiques, afin d'identifier les mécanismes moléculaires responsables de la plasticité des MSCTs. Dans l'ensemble, cette nouvelle mesure de la plasticité synaptique présente le potentiel de fournir de nouvelles connaissances sur la diversité des processus moléculaires qui régissent la potentialisation synaptique. / Classical measurements of synaptic plasticity have involved electrophysiological methods which provide high sensitivity for detecting small changes in synaptic strength. However, this approach does not provide much information about the location of the synapses that undergo plastic changes. Because synaptic plasticity can be synapse-specific, having the ability to monitor changes in synaptic strength at individual synapses is important in order to enable simultaneously monitoring of local molecular mechanisms associated with the plasticity. New fluorescent tools developed in the last decades allow to directly visualize synaptic activity, signaling, and remodeling at individual synapses. During my Master studies, I used optical imaging of a genetically-encoded calcium (Ca2+) sensor, GCaMP6f, to record miniature synaptic Ca2+ transients (MSCTs) in cultured rat hippocampal neurons. For these experiments, I performed video-microscopy on neurons perfused with external solution lacking Mg2+ and containing Tetrodotoxin (0Mg2+/TTX). I have observed highly localized and transient increases of intracellular Ca2+ in dendritic compartments and spines. To test whether these MSCTs can be potentiated, I have measured them before and after a 5 min stimulation known to induce plasticity in cultured neurons (0Mg2+/Glycine/Bicuculline, cLTP). A lasting increase in the frequency and amplitude of MSCTs, for at least an hour, arose from this stimulation protocol. I have thus investigated the molecular mechanisms of this plasticity. The MSCTs are mostly mediated by NMDA receptors, since they are almost totally blocked by the selective antagonist to the receptor, AP5. Moreover, addition of AP5 only during the cLTP stimulation blocks the MSCT plasticity. It thus appears that both the MSCTs and their plasticity are NMDA receptor-dependent. Interestingly, the MSCTs and their plasticity are not blocked by the AMPA receptor antagonists NBQX, pointing to possible changes in NMDA receptor content, postsynaptic Ca2+ signaling, or presynaptic neurotransmitter release. Also, while we found that CaMKII signaling is non-essential for the induction of the plasticity, preliminary data are showing a plausible PKA-dependency of the plasticity. To test these hypotheses, I have also tried to combine Ca2+ imaging with imaging of other pre and postsynaptic components, to identify the molecular mechanisms responsible for the MSCT plasticity. Overall, this new approach presented in this thesis might provide new knowledge on the diversity of molecular processes that support synaptic potentiation.

In the past decade, reinforcement learning (RL) has achieved breakthroughs across various domains, from surpassing human performance in strategy games to enhancing the training of large language models (LLMs) with human feedback. However, RL has yet to gain widespread adoption in mission-critical fields such as healthcare and autonomous vehicles. This is primarily attributed to the inherent lack of trust, explainability, and generalizability of neural networks in deep reinforcement learning (DRL) agents. While neural DRL agents leverage the power of neural networks to solve specific tasks robustly and efficiently, this often comes at the cost of explainability and generalizability. In contrast, pure symbolic agents maintain explainability and trust but often underperform in high-dimensional data. In this work, we developed a method to distill explainable and trustworthy agents using neuro-symbolic AI. Neuro-symbolic distillation combines the strengths of symbolic reasoning and neural networks, creating a hybrid framework that leverages the structured knowledge representation of symbolic systems alongside the learning capabilities of neural networks. The key steps of neuro-symbolic distillation involve training traditional DRL agents, followed by extracting, selecting, and distilling their learned policies into symbolic forms using symbolic regression and tree-based models. These symbolic representations are then employed instead of the neural agents to make interpretable decisions with comparable accuracy. The approach is validated through experiments on Lunar Lander and Pong, demonstrating that symbolic representations can effectively replace neural agents while enhancing transparency and trustworthiness. Our findings suggest that this approach mitigates the black-box nature of neural networks, providing a pathway toward more transparent and trustworthy AI systems. The implications of this research are significant for fields requiring both high performance and explainability, such as autonomous systems, healthcare, and financial modeling.

Titre de l'écran-titre (visionné le 31 octobre 2023) / L'imagerie par résonance magnétique fonctionnelle (IRMf) est une technique d'imagerie non invasive. Celle-ci utilise les champs magnétiques afin de mesurer les changements hémodynamiques induits par le mécanisme du couplage neurovasculaire dans une région du cerveau donnant une mesure indirecte de l'activité neuronale. La réalisation d'études IRMf sur des souris éveillées pose diverses difficultés et défis techniques nécessitant l'utilisation de sédatifs ou d'anesthésiques. Or, certains facteurs comme le stress et l'état d'anesthésie sont reconnus pour altérer la fonction cérébrale affectant simultanément la fidélité des résultats recueillis. Le but de ce projet est ainsi d'étudier la faisabilité de l'imagerie par résonance magnétique fonctionnelle à 1 tesla chez la souris éveillée. D'abord, une méthode de fixation a été développée afin de restreindre les mouvements d'une souris permettant de l'imagerie anatomique et fonctionnelle in vivo. Un paradigme en bloc alternant une période de repos et une période de stimulation a été élaboré en utilisant un mélange gazeux de dioxyde de carbone et d'oxygène à titre de stimulation. Le tout, afin d'induire des changements sanguins comparables à ceux provoqués par le couplage neurovasculaire. Ensuite, une analyse statistique, sur les images fonctionnelles, a permis d'obtenir deux cartes d'activation en comparant les deux différents blocs avec stimulation et au repos. Finalement, les résultats obtenus à l'IRMf sont comparés avec la technique d'imagerie optique intrinsèque pour vérifier la concordance des réponses mesurées par diverses méthodes d'imagerie. Ainsi, l'obtention de ces cartes montre qu'une étude IRMf sur une IRM 1T avec souris éveillée est possible. / Functional magnetic resonance imaging (fMRI) is a non-invasive imaging technique that uses magnetic fields to measure hemodynamic changes induced by the mechanism of neurovascular coupling in a region of the brain giving an indirect measure of neuronal activity. Performing fMRI studies on awake mice poses various technical difficulties and challenges requiring the use of sedatives or anesthetics. However, certain factors such as stress and the state of anesthesia are known to alter brain function, simultaneously affecting the fidelity of the collected results. The aim of this project is to study the feasibility of functional magnetic resonance imaging at 1 tesla in awake mice. First, a mouse holder was developed to restrict the movements of a mouse's head allowing for anatomical and functional imaging in vivo. A block paradigm of alternating a period of rest and a period of stimulation was developed using a gaseous mixture of carbon dioxide and oxygen as stimulation in order to induce blood changes comparable to those caused by neurovascular coupling. Then, a statistical analysis on those functionals images made it possible to obtain two activation maps by comparing the two different blocks of stimulation and at rest. Finally, the results obtained by fMRI are compared with the intrinsic optical imaging technique to verify the concordance of the responses through different imaging methods. Thus, obtaining these maps shows that an fMRI study on a 1T MRI with awake mice is possible.

Les démences sont un enjeu majeur de santé. La dégénérescence lobaire fronto-temporale (DLFT), deuxième forme la plus prévalente de démence chez les personnes âgées de moins de 65 ans, inclut entre autres la variante sémantique de l’aphasie primaire progressive (svPPA), une maladie qui affecte particulièrement et initialement le langage. Anatomiquement, on sait déjà qu’on retrouve en svPPA une atrophie principalement marquée au niveau temporal, davantage à gauche et en antérieur. La connaissance des atteintes de la matière blanche est toutefois moins étoffée pour l’instant. Au niveau thérapeutique, il existe une controverse quant à l’approche à privilégier en DLFT : plusieurs molécules ont été étudiées, plusieurs sont prescrites et pourtant il n’y a ni consensus, ni recommandation à cet effet. Nos objectifs dans ce mémoire sont donc d’abord de mieux caractériser les atteintes cérébrales de la matière blanche et de la matière grise chez les patients atteints de svPPA, par une étude tractographique et volumétrique, et ensuite d’évaluer l’efficacité de la pharmacothérapie chez les patients avec DLFT en termes d’effet sur la cognition et sur des symptômes neuropsychiatriques, grâce à une revue systématique avec méta-analyse. En imagerie, notre étude a montré une diminution de la diffusion au niveau du fascicule longitudinal supérieur gauche, de la capsule externe gauche, du cingulum droit et du fascicule unciné bilatéralement et une atrophie plus marquée en temporal gauche, ainsi qu’au niveau de l’amygdale et des cortex fusiforme et entorhinal. En pharmacothérapie, aucune médication n’a démontré d’effet sur la cognition globale, mais certaines molécules ont montré un bénéfice potentiel sur le langage, l’impulsivité et la reconnaissance des émotions. Ce mémoire a ainsi permis des avancées au niveau de la caractérisation des atteintes cérébrales en svPPA et de faire le point sur l’état de la littérature en pharmacothérapie de la DLFT. / Dementia is a major health issue. Frontotemporal lobar degeneration (FTLD), the second most common dementia in individuals under 65 years of age, includes the semantic variant of primary progressive aphasia (svPPA), a disease affecting mainly and initially language. Anatomically, we know that svPPA patients show cortical atrophy, markedly in the temporal lobes, more in the left hemisphere and anteriorly. However, our knowledge of white matter damage is less developed. As for FTLD pharmacotherapies, there remains much controversy. Many molecules have been studied, some are currently prescribed, but there still is no consensus, nor any recommendation to this effect. Our objectives in this memoir were first to better characterize cerebral damage for white and grey matter in svPPA patients by means of a tractographic and volumetric study, and secondly to assess the effect on global cognition and specific neuropsychiatric symptoms of pharmacotherapy in FTLD patients, with a systematic review and meta-analysis. Imaging results show a diminution of fractional anisotropic diffusion in the left superior longitudinal fasciculus, external capsule, right cingulum and bilateral uncinate fasciculi. They also show atrophy, markedly in the left temporal lobe, amygdala, fusiform and entorhinal cortices. As for pharmacotherapy results, no medication was shown to have any beneficial effects on global cognition, but some drugs may improve language, impulsivity and emotion recognition. This memoir has indeed improved the characterization of cerebral damage in the svPPA and reviewed thoroughly the literature on pharmacotherapy in FLTD.