186 research outputs found

    Spaces in-between: a transitional inquiry into transitionality

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    Working between the philosophy of Deleuze and Guattari and the psychoanalysis of Winnicott, through stories and creative writing, I create new concepts and understandings of the notion of assemblages. This thesis is a playful exploration of experiences, thinking with theory, making a creative-relational inquiry. Moving between the refrain and the transitional object, I work with the idea of a transitional inquiry: between the internal and external, between the conscious and unconscious, producing something-in-the-world. Even though it is personal, this type of inquiry de-centres the notion of the subject to include objects, machines, and the creation of territories as fundamental aspects to understand human processes. One of the main contributions of working with Deleuze, Guattari, and Winnicott is to think the transitional object together with the refrain and propose a holding-machine to help other machines develop and process assemblages. This concept emerges while working with stories of trauma, understanding them as moments where the subject cannot process events and affects. This exploration is about spaces in-between, spaces that are not entirely what they are, as they move between the created and the discovered, between the intensities and extensions, fantasy, and reality

    INNOVATIVE DIGITAL START-UPS AND THEIR VENTURE CREATION PROCESS WITH ENABLING DIGITAL PLATFORMS

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    Start-ups have gained media attention since Google, Facebook and Amazon were launched in the 1990s. The book Lean Start-up, published in 2011, was another important milestone for digital start-up literature. As unicorn companies emerge around the world, topics highlighted in the news include the vast amount of capital that digital start-ups are raising, the ways in which these digital ventures are disrupting industries, and their global impact on digital economy. However, digital start-ups, digital venture ideas, and their venture creation process lack a unified venture creation model, as there is a gap in the re-search on entrepreneurial processes in a digital context. This research is an explorative study of the venture creation process of innovative digital start-ups that examines what is missing from entrepreneurial process models in a digital technology context and investi-gates how early stage digital start-ups conduct the venture creation process, starting with the pre-phase of antecedents and ending with the launch and scaling of the venture. The research proposes a novel process model of innovative digital start-up venture crea-tion and describes the nature and patterns of the process. A conceptual model was devel-oped based on the entrepreneurship, information systems, and digital innovation litera-ture and empirically assessed with a multi-method qualitative research design. The data collected from semi-structured interviews, internet sources, and observation field notes covered 34 innovative digital start-ups and their founders. Interviews were conducted in-ternationally in high-ranking start-up ecosystems, and the data were analysed with the-matic analysis and fact-checked by triangulating internet data sources. The contribution to entrepreneurship theory is a new illustrative model of the venture creation process of innovative digital start-ups, including the emergent outcome of the process having a digi-tal artefact at its core (e.g., mobile apps, web-based solutions, digital platforms, software solutions, and digital ecosystems). Digital platforms and their multiple roles in the process are presented, as well as the role of critical events as moderators of the process which trigger new development cycles. During the venture creation process, the recombining of digital technologies, modules, and components enabled by digital infrastructures, plat-forms, and ecosystem partners represent digital technology affordances. This recombina-tion provides opportunities for asset-free development of digital venture ideas

    Distributed Control and State Estimation of DC Microgrids Based on Constrained Communication Networks.

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    PhD ThesesThe intermittent nature of renewable energy sources (RES) such as wind turbines and photovoltaic panels, requires advanced control systems to provide the balance between energy supply and demand in any power system. For better management of power quality and security issues, energy storage systems (ESSs) are deployed to compensate for the temporary mismatch of supply and demand. Furthermore, in rural areas with no connection to the main grid, ESSs such as batteries are deployed in large quantities as a solution for temporary power stabilization during RES unavailability. However, the control complexity of the power system increases as more ESSs are getting installed due to the need for coordination of the power transfer among them. This thesis undertakes a thorough analysis of distributed control and state estimation designs for direct current (DC) microgrids with ESSs based on constrained communication networks. The developed distributed control and estimation strategies are designed for operation over constrained communication networks. They don't require a central coordinator for synchronization of the control tasks between the ESSs. This forms a multi-agent environment where the controllers cooperatively achieve the DC microgrid objectives, i.e. voltage stabilization, proportional power-sharing, and balancing of ESSs' energy level. To overcome the communication network constraints, event-based controllers and estimators are designed, which e ectively reduce the network tra c and as a result, provide higher throughput with reduced delays for the real-time control loops of the DC microgrids. The controllers are designed to be distributed, leading to use cases such as autonomous islanded microgrids, smart villages, and plug-and-play mobile microgrids. The feasibility and performance of the proposed control and estimation strategies are con rmed in several experimental test benches by showing the higher reliability and robustness in the delivered power quality. The results have shown considerable reduction in the network tra c, meanwhile the control system provided high performance in terms of stability, robustness, power quality and endurabilit

    THE MANY WAYS OF WAKING UP FROM SLEEP - MOVING FORWARD THE ANALYSIS OF SLEEP MICROARCHITECTURE

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    One of the defining characteristics of sleep is that it is readily reversible towards wakefulness. This is exemplified in the common daily experience of waking up in the morning. My thesis studies sleep-wake transitions that are equally common and frequent, yet often not consciously perceived and neglected as random sleep perturbations of minor significance. Using mice as an experimental species, I find that healthy non-rapid-eye-movement sleep (NREMS), also named deep restorative sleep, is a dynamic brain state showing defined, periodically recurring moments of fragility. During these, diverse types of brief arousal-like events with various combinations of physiological correlates appear, including global or local cortical activation, muscle activity, and heart rate changes. Using a mice model of chronic neuropathic pain, I find that the rules I have identified in healthy sleep serve to identify previously unrecognized sleep disruptions that could contribute to sleep complaints of chronic pain patients. The experimental and analytical methods I have developed in these studies also helped in the identification of the neuronal basis of the fragility periods of NREM sleep. Together, my studies offer novel insights and analytical tools for the study of sleep-wake transitions and their perturbance in pathological conditions linked to sensory discomfort. More specifically, my work departed from recent findings that NREMS in mice is divided in recurring periods of sleep fragility at frequencies ~0.02 Hz, characterized by heightened arousability. Through analyzing the temporal distribution of brief arousal events termed microarousals, I hypothesized that these fragility periods could serve a time raster for the probing of spontaneous sleep perturbations. Motivated by the question of how sensory discomfort caused by pain affects sleep, I have used the spared nerve injury (SNI) model, which consists in the injury of two of the 3 branches of the sciatic nerve. I found that the role of fragility periods in timing spontaneous arousals is highly useful to identify sleep disruptions not commonly detected with standard polysomnographic measures. Thus, by scrutinizing the fragility periods of NREMS in the SNI mice, I discovered an overrepresentation of a novel form of local perturbation within the hindlimb primary somatosensory cortex (S1HL), accompanied by heart rate increases. In addition, I showed that SNI animals woke up more frequently facing external stimuli, using closed-loop methods targeting specifically the fragility or continuity periods. These findings led me to propose that chronic pain-related sleep complaints may arise primarily from a perturbed arousability. The closed-loop techniques to probe arousability could be transferred to interrogate neuronal mechanisms underlying NREMS fragility, leading to the recognition that intrusion of wake-related activity into NREMS is a previously underappreciated mechanism controlling sleep fragility and architecture. Overall, I present my thesis to advance the view on NREMS as a dynamic heterogeneous state of which insights into its neuronal mechanisms, and its physio- and pathophysiological manifestations in animal models should be key to formulate testable hypotheses aimed to cure the suffering of sleep disorder in human. -- Une des caractĂ©ristiques qui dĂ©finit le sommeil, est que l’on peut rapidement retourner Ă  un Ă©tat d’éveil. De fait, nous l’expĂ©rimentons chaque matin au rĂ©veil. Ma thĂšse Ă©tudie les transitions sommeil-Ă©veil qui, bien que frĂ©quentes, sont souvent non consciemment perçues et traitĂ©es comme des perturbations sans importance et alĂ©atoires du sommeil. En utilisant la souris comme modĂšle expĂ©rimental, je montre que le sommeil sans mouvements rapides des yeux (NREMS), Ă©galement appelĂ© le sommeil profond et rĂ©parateur, est un Ă©tat cĂ©rĂ©bral dynamique composĂ© de pĂ©riodes discrĂštes et rĂ©currentes de fragilitĂ© face Ă  des stimuli externe. Pendant celles-ci, plusieurs types d’évĂšnements associĂ©s Ă  des Ă©veils brefs apparaissent, combinant activation corticale, activitĂ© musculaire et/ou une hausse des battements cardiaques. Je dĂ©montre que la comprĂ©hension des transitions sommeil-Ă©veil physiologiques s’avĂšre utile pour Ă©tudier le sommeil de souris souffrant de douleurs neuropathiques chroniques. Ces souris prĂ©sentent un nouveau type de perturbations locales lors du sommeil, qui pourraient possiblement expliquer une partie des plaintes de mauvais sommeil exprimĂ©es par les patients souffrant de douleurs chroniques. Les mĂ©thodes analytiques et expĂ©rimentales que j’ai dĂ©veloppĂ©es dans ces Ă©tudes ont aussi aidĂ© Ă  l’identification des bases neuronales de la genĂšse des pĂ©riodes de fragilitĂ©s du sommeil NREM. En somme, mes Ă©tudes offrent des connaissances inĂ©dites et des mĂ©thodes d’analyses pour l’étude des transitions sommeil-Ă©veil et de leurs perturbations en conditions pathologiques. Une Ă©tude rĂ©cente du laboratoire a montrĂ© que le sommeil NREM est divisĂ© en pĂ©riodes de fragilitĂ© alternant avec des pĂ©riodes de non-fragilitĂ© (continuitĂ©), environ toutes les 50 secondes ce qui donne une frĂ©quence de 0.02 Hz. Les pĂ©riodes de fragilitĂ© sont caractĂ©risĂ©es par une hausse de « l’éveillabilitĂ© » ou propension Ă  s’éveiller. Ma premiĂšre observation est que les Ă©veils brefs, couramment appelĂ©s micro-rĂ©veils, prĂ©sentent une distribution temporelle hautement restreinte aux pĂ©riodes de fragilitĂ©. Ainsi, j’ai Ă©mis l’hypothĂšse que ces pĂ©riodes pourraient servir de moments spĂ©cialement choisis par le cerveau pour la mesure de potentielles perturbations spontanĂ©es. MotivĂ© par la question de comment les douleurs chroniques perturbent le sommeil, je l’ai analysĂ© chez un modĂšle de souris de douleurs neuropathique, le modĂšle de d’épargne du nerf sural (SNI). Le rĂŽle des pĂ©riodes de fragilitĂ© Ă  restreindre les micro- rĂ©veils s’est avĂ©rĂ© trĂšs utile pour dĂ©tecter de nouvelles formes de rĂ©action Ă  des perturbations qui ne sont pas Ă©videntes par des analyses classiques du sommeil. En effet, spĂ©cifiquement pendant ces pĂ©riodes de fragilitĂ©, j’ai dĂ©couvert une sur-reprĂ©sentation d’un nouveau type d’éveil local confinĂ© au cortex somatosensoriel primaire et accompagnĂ© d’une hausse du rythme cardiaque. De plus, en utilisant de nouvelles mĂ©thodes basĂ©es sur des boucles-fermĂ©es, j’ai dĂ©montrĂ© que les souris SNI se rĂ©veillaient plus frĂ©quemment que leurs contrĂŽles en faisant face Ă  des stimuli externes. Sur la base de ces dĂ©couvertes, je propose que les plaintes de mauvais sommeil chez les patients souffrant de douleurs chroniques puissent prendre leur source dans une Ă©veillabilitĂ© perturbĂ©e. Les mĂ©thodes de boucles-fermĂ©es pour analyser l’éveillabilitĂ© a aussi pu ĂȘtre transfĂ©rĂ©e pour l’étude optogĂ©nĂ©tique des mĂ©canismes neuronaux Ă  la base de la fragilitĂ© du sommeil NREM. Cela a menĂ© Ă  la reconnaissance que l’intrusion d’activitĂ© normalement associĂ©e Ă  l’éveil dans le sommeil est un mĂ©canisme de contrĂŽle de sa fragilitĂ© et de son architecture souvent ignorĂ© dans le domaine. En somme, ma thĂšse permet une avancĂ©e de notre vision du sommeil NREM comme Ă©tant un Ă©tat dynamique et hĂ©tĂ©rogĂšne dont les mĂ©canismes neuronaux sous-jacent, en conditions normales et pathogĂ©niques, sont clefs pour la formulation d’hypothĂšses testables visant Ă  la guĂ©rison des patients souffrant de troubles du sommeil

    Recent Development of Hybrid Renewable Energy Systems

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    Abstract: The use of renewable energies continues to increase. However, the energy obtained from renewable resources is variable over time. The amount of energy produced from the renewable energy sources (RES) over time depends on the meteorological conditions of the region chosen, the season, the relief, etc. So, variable power and nonguaranteed energy produced by renewable sources implies intermittence of the grid. The key lies in supply sources integrated to a hybrid system (HS)

    Leveraging Machine Learning Techniques towards Intelligent Networking Automation

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    In this thesis, we address some of the challenges that the Intelligent Networking Automation (INA) paradigm poses. Our goal is to design schemes leveraging Machine Learning (ML) techniques to cope with situations that involve hard decision-making actions. The proposed solutions are data-driven and consist of an agent that operates at network elements such as routers, switches, or network servers. The data are gathered from realistic scenarios, either actual network deployments or emulated environments. To evaluate the enhancements that the designed schemes provide, we compare our solutions to non-intelligent ones. Additionally, we assess the trade-off between the obtained improvements and the computational costs of implementing the proposed mechanisms. Accordingly, this thesis tackles the challenges that four specific research problems present. The first topic addresses the problem of balancing traffic in dense Internet of Things (IoT) network scenarios where the end devices and the Base Stations (BSs) form complex networks. By applying ML techniques to discover patterns in the association between the end devices and the BSs, the proposed scheme can balance the traffic load in a IoT network to increase the packet delivery ratio and reduce the energy cost of data delivery. The second research topic proposes an intelligent congestion control for internet connections at edge network elements. The design includes a congestion predictor based on an Artificial Neural Network (ANN) and an Active Queue Management (AQM) parameter tuner. Similarly, the third research topic includes an intelligent solution to the inter-domain congestion. Different from second topic, this problem considers the preservation of the private network data by means of Federated Learning (FL), since network elements of several organizations participate in the intelligent process. Finally, the fourth research topic refers to a framework to efficiently gathering network telemetry (NT) data. The proposed solution considers a traffic-aware approach so that the NT is intelligently collected and transmitted by the network elements. All the proposed schemes are evaluated through use cases considering standardized networking mechanisms. Therefore, we envision that the solutions of these specific problems encompass a set of methods that can be utilized in real-world scenarios towards the realization of the INA paradigm

    Contributing to the development of social pedagogy in the UK: a case study at 'Santiago 1' residential care home in Spain

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    In recent years there has been a growing interest in social pedagogy in the UK, much of which has focused on residential care for looked after children, a system that has been under scrutiny over recent decades. Research carried out in other European countries where social pedagogy is an established academic discipline and profession, alongside pilot programmes, training courses and practical initiatives in the UK, have shed light on what not that long ago was an unknown field in this country. These European studies suggest that social pedagogical approaches might potentially help to improve residential care in the UK. This research aims to contribute to the development of social pedagogy in the UK through the study of its practice in Spain, where there is a significant tradition in this field. In order to do it, I have carried out a case study in a residential care institution working to a social pedagogic approach named “Santiago 1”. In a time when the tendency is to provide small family-like homes for children in care, Santiago 1 offers an example of a big institution (around 100 residents in total) where education, both in its more formal and informal versions, is at the core of their intervention. Through this case study, I have sought to find how its practice can inform a conceptualisation of social pedagogy and the possible implications of this for the current residential care situation in the UK. I designed an inductive study, using qualitative ethnographic methods (participant observation and semi-structured interviews) for data collection, followed by a thematic data analysis. The findings arguably make such desired contribution. The findings confirm some of the notions and principles already existing in the academic body of knowledge in the field of social pedagogy. However, they also give insight into aspects that are frequently overlooked, such as creating an educative intervention that goes beyond the target group to have an impact on the community, and making use of group work and living as a cornerstone for the social pedagogic intervention. These perspectives lead to a discussion in which I point out the implications of trying to implement these social pedagogic ideas and practices in the UK and argue for the need for several changes in the current residential care system and the regulations that frame it that would be required in order to do so
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