| 1. |
- Kotte, Hari Babu, 1979-
(författare)
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High Frequency (MHz) Resonant Converters using GaN HEMTs and Novel Planar Transformer Technology
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increased power consumption and power density demands of moderntechnologies have increased the technical requirements of DC/DC and AC/DC powersupplies. In this regard, the primary objective of the power supply researcher/engineeris to build energy efficient, high power density converters by reducing the losses andincreasing the switching frequency of converters respectively. Operating the convertercircuits at higher switching frequencies reduces the size of the passive componentssuch as transformers, inductors, and capacitors, which results in a compact size,weight, and increased power density of the converter. Therefore, the thesis work isfocussed on the design, analysis and evaluation of isolated converters operating in the1 - 5MHz frequency region with the assistance of the latest semi conductor devices,both coreless and core based planar power transformers designed in Mid SwedenUniversity and which are suitable for consumer applications of varying power levelsranging from 1 – 60W.In high frequency converter circuits, since the MOSFET gate driver plays a prominentrole, different commercially available MOSFET gate drivers were evaluated in thefrequency range of 1 - 5MHz in terms of gate drive power consumption, rise/fall timesand electromagnetic interference (EMI) and a suitable driver was proposed.Initially, the research was focused on the design and evaluation of a quasi resonantflyback converter using a multilayered coreless PCB step down transformer in thefrequency range of 2.7 – 4MHz up to the power level of 10W. The energy efficiency ofthis converter is found to be 72 - 84% under zero voltage switching conditions (ZVS).In order to further improve the energy efficiency of the converter in the MHzfrequency region, the new material device GaN HEMT was considered. Thecomparisons were made on a quasi resonant flyback DC-DC converter using both theSi and GaN technology and it was found that an energy efficiency improvement of 8 –10% was obtained with the GaN device in the frequency range of 3.2 – 5MHz. In orderto minimize the gate drive power consumption, switching losses and to increase thefrequency of the converter in some applications such as laptop adapters, set top box(STB) etc., a cascode flyback converter using a low voltage GaN HEMT and a highvoltage Si MOSFET was designed and evaluated using a multi-layered coreless PCBtransformer in the MHz frequency region. Both the simulation and experimentalresults have shown that, with the assistance of the cascode flyback converter, theswitching speeds of the converter can be increased with the benefit of obtaining asignificant improvement in the energy efficiency as compared to that for the singleswitch flyback converter.In order to further maximize the utilization of the transformer, to reduce the voltagestress on MOSFETs and to obtain the maximum power density from the convertercircuit, double ended topologies were considered. Due to the lack of high voltage highside gate drivers in the MHz frequency region, a gate drive circuitry utilizing themulti-layered coreless PCB signal transformer was designed and evaluated in both ahalf-bridge and series resonant converter (SRC). It was found that the gate drive powerconsumption using this transformer was around 0.66W for the frequency range of 1.5 -v3.75 MHz. In addition, by using this gate drive circuitry, the maximum energyefficiency of the SRC using multilayered coreless PCB power transformer was found tobe 86.5% with an output power of 36.5W in the switching frequency range of 2 –3MHz.In order to further enhance the energy efficiency of the converter to more than 90%,investigations were carried out by using the multiresonant converter topology (LCCand LLC), novel hybrid core high frequency planar power transformer and the GaNHEMTs. The simulated and experimental results of the designed LCC resonantconverter show that it is feasible to obtain higher energy efficiency isolated DC/DCconverters in the MHz frequency region. The peak energy efficiency of the LCCconverter at 3.5MHz is reported to be 92% using synchronous rectification. Differentmodulation techniques were implemented to regulate the converter for both line andload variations using a digital controller.In order to realize an AC/DC converter suitable for a laptop adapter application,consideration was given to the low line of the universal input voltage range due to theGaN switch limitation. The energy efficiency of the regulated converter operating inthe frequency range of 2.8 – 3.5MHz is reported to be more than 90% with a loadpower of 45W and an output voltage of 22Vdc. In order to determine an efficient powerprocessing method on the secondary side of the converter, a comparison was madebetween diode rectification and synchronous rectification and optimal rectification wasproposed for the converters operating in the MHz frequency range for a given powertransfer application. In order to maintain high energy efficiency for a wide load rangeand to maintain the narrow switching frequency range for the given input voltagespecifications, the LLC resonant converter has been designed and evaluated for theadapter application. From the observed results, the energy efficiency of the LLCresonant converter is maintained at a high level for a wide load range as compared tothat for the LCC resonant converter.Investigations were also carried out on isolated class E resonant DC-DC converter withthe assistance of GaN HEMT and a high performance planar power transformer at theswitching frequency of 5MHz. The simulated energy efficiency of the converter for theoutput power level of 16W is obtained as 88.5% which makes it feasible to utilize thedesigned isolated converter for various applications that require light weight and lowprofile converters.In conclusion, the research in this dissertation has addressed various issues related tohigh frequency isolated converters and has proposed solution by designing highlyenergy efficient converters to meet the current industrial trends by using coreless andcore based planar transformer technologies along with the assistance of GaN HEMTs.With the provided solution, in the near future, it is feasible to realize low profile, highpower density DC/DC and AC/DC converters operating in MHz frequency regionsuitable for various applications.
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| 2. |
- Cole, Tomas, 1983-
(författare)
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Possessed Earth : Ownership and Power in the Salween Peace Park of Southeast Myanmar
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the wake of seven decades of protracted revolution and armed conflict in Southeast Myanmar, an ensemble of indigenous peoples and transnational activists have begun formulating a radical alternative vision of how peace and conservation might be achieved in practice. Through translating and rescaling indigenous modes of possessing the earth, this ensemble is working to transform 5,000 km2 of highly contested terrain in the highlands along the Salween River into a conservation zone they call the Salween Peace Park.In this study I explore what indigenous practices and cosmologies, and the ways they are being translated and rescaled into the Salween Peace Park, might teach us about ownership, sovereignty, and politics at large.The first half of this study focuses on the highlands along the Salween River, to explore how people residing here commonly treat their landscapes as already possessed, in the dual and entangled senses of being both occupied or haunted by spectral more-than-human presences, and controlled and owned by them. In these Possessed Landscapes human ownership of land is always ephemeral, ultimately nesting in the encompassing ownership of spectral presences (who I describe as persons). Humans can only borrow land by constantly negotiating with and propitiating its spectral owners. A corollary of these indigenous modes of possessing the earth is that these highlands were not so much anarchic as in sense of “no ruler”, but rather, power and sovereignty is nesting in the hands of the spectral owners of the earth. I describe this as an alternative mode of politics that I name Spectral Sovereignty. In the second half I take a small step back to shuttle between the residents of these highlands and networks of activists based in Chiang Mai in Thailand. Here I focus on both growing new forms of dispossession and counterinsurgency that have accompanied the cooling of armed conflict, and efforts by ensembles of indigenous peoples, activists, armed groups, and conservationists to attempt to push back and re-territorialise and re-possess the earth. I go on to explore how this ensemble is subtly translating and rescaling possessed landscapes and spectral sovereignty into land laws and conservation policy as a way to transform these former war zones into a protected area, the Salween Peace Park. I then show how, in the process of establishing this protected area, these activists are continuing the revolutionary movements to attain greater autonomy for the indigenous people residing here. I then close this thesis by exploring what is happening as the Salween Peace Park is coming into contact and being negotiated on the ground in these highlands. Here we find revolutionary politics and spectral sovereignty are becoming entwined into a form of Alter-Politics that is unsettling established notions of sovereignty and politics. However, beyond unsettling, it also gestures towards alternative ways of understanding the shifting entanglements between people, politics, spectres, and other unseen more-than-humans, and radical alternatives to conservation and armed conflict in Myanmar, and beyond.
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| 3. |
- De Lima, Wenderson, 1981-
(författare)
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Modern Missionaries : An Ethnography of Social Entrepreneurs and Entrepreneurial Legitimation in the Humanitarian Field
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In nearly six decades of international interventions, the question of how to promote societal progress in African societies is still the subject of lively debates. The persistence of wars, famine, political instability and economic underdevelopment on the continent continues to fuel spirited discussions about how to organize aid most efficiently and whether old forms of international assistance still work. In this scenario, modern missionaries appear bearing promises to solve poverty related problems. Some of these people call themselves: ‘social entrepreneurs’. These entrepreneurs have during the last decade gained increased space in the humanitarian field. Based on the premise that business and self-interest may in fact be the most effective way to assist the ‘extreme poor’ in the Global South, entrepreneurs and social entrepreneurs have increasingly begun to gain recognition as innovative humanitarian players. By applying business principles and practices to the humanitarian field, social entrepreneurs are constructed as challengers of previously institutionalized forms of organizing aid, such as charities and NGOs. The aim of this dissertation is to create a greater understanding of how social entrepreneurs gain legitimacy in the humanitarian field. Drawing on ethnographic methods, I address this aim by exploring the realities of social entrepreneurs creating organizations in Kenya’s largest urban slum Kibera, in Nairobi. I argue that, to gain legitimacy in the humanitarian field, social entrepreneurs depend on the interplay between social, cultural, symbolic and economic capital. Furthermore, I emphasize the symbolic power of places in the processes by which entrepreneurs gain social acceptance and support for their interventions. While seemingly fostering social transformation and entrepreneurship in the Global South, social entrepreneurs may informally create and support an economy which justifies the existence of NGOs in Kibera. Within this economy local actors create several mechanisms for profiting from foreign led organizations. This phenomenon I call ‘unexpected entrepreneurship’: activities that emerge as reactions to processes of development and the delivery of humanitarian services and products as well as the implementation of policies. Although often commercial and informal in nature, this form of entrepreneurship influences how social entrepreneurs gain access to local settings. Unexpected entrepreneurship also changes how social entrepreneurs design and deliver their solutions.
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| 4. |
- Engström, Annica, 1967-
(författare)
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Dimmornas bro : En berättelse om konstruktionen och iscensättandet av kliniska adjunkter
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation is a study of a relatively new teacher function in nurse education, a teacher function that can be called clinical teacher, link lecturer, link teacher or lecturer involved in practice. The study departs from a constructivist perspective and the aim is to study the introduction, performance and regulation of this teacher function. The material consists of internationally and nationally published research 1978-2009, reports from the authorities, job ads for clinical teachers, job descriptions and contracts, archive material, evaluation studies, professional journals, texts on the Internet and 15 interviews with clinical teachers in Sweden. Using discourse analysis this material is studied in terms of interpretive repertoires, subject positions and ideological dilemmas. The primary focus of this dissertation concerns what problems the new teacher function is supposed to solve, how the problem should be solved, the effects of the chosen solutions and what´s staged, challenged and reproduced. Secondly, this dissertation highlights what categories of teachers are required and in demand for the new teacher function, how the teachers themselves manage their function and how the teacher function is maintained and challenged. The analysis identifies and highlights current interpretive repertoire, teachers possible subject positions and ideological dilemmas and how they are governed and challenged in the teaching function.
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| 5. |
- Mitchell, Andrew, 1975-
(författare)
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Tracing Wolves : Materiality, Effect and Difference
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As wolves are seldom seen in Scandinavia, Tracing Wolves utilises the ‘trace’ as both a theoretical and methodological tool to aid comprehension of what a wolf is and what a wolf does. Consequently, this enquiry examines human-wolf practices, such as tracking, genetic analysis, GPS tracking, hunting, and wolf necropsies, via which Scandinavian wolves in Sweden manifest. It is in this respect, through the traces wolves leave – like tracks in the snow, a steaming scat, the remains of a recent kill, GPS data or genetic material – that humans come to know wolves. Furthermore, this study also employs the ‘trace’ as a way to navigate through the complexities of material-semiotics and post-human approaches to method and theory, and contemplates rather more traditional approaches to anthropological knowledge. Accordingly, by considering the materiality of human-wolf encounters and how effects are comprehended and differences emerge, this analysis highlights that some of theses practices, aided by empathy and embodiment, facilitate a sociality that operates across species boundaries.
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| 6. |
- Rodineliussen, Rasmus, 1990-
(författare)
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Underwater Worlds : An Ethnography of Waste, Pollution, and Marine Life
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this dissertation, I investigate relations between humans, waste, pollution, and marine life. I introduce the concept of Aquabiopolitics as a means to understand how humans govern life in water in order to enrich human life on land. The study focuses on the Baltic Sea and Lake Mälaren, using Stockholm, the capital of Sweden, as the connection point. Throughout the dissertation, I explore how human practices over time have had devastating effects on marine life and continue to have so today. The dissertation engages with the marine world through underwater ethnography to provide a perspective on water from below the surface. In this endeavor, I employ the assistance of marine scientists and trash scuba divers who are jointly invested in tracking human maltreatment of water and finding solutions for treating water differently in the future. We will follow the scientists on expeditions at sea and to their laboratories in order to learn about their methods and relations to underwater worlds. Together with the trash scuba divers, we will dive into the dark murky waters around Stockholm—experiencing what it is like to move below water, among sharp and toxic waste, without any visibility. The work of creating a knowing and caring relationship between humans and water is of key importance to both scientists and divers. Therefore, one of the main parts of this dissertation is to analyze how, and if, this relationship can be created: via social media, images, installations, or other means. For as the divers often say: Water is Life. Make it Important!
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| 7. |
- Angelov, Angel G., 1983-
(författare)
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Methods for interval-censored data and testing for stochastic dominance
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis includes four papers: the first three of them are concerned with methods for interval-censored data, while the forth paper is devoted to testing for stochastic dominance.In many studies, the variable of interest is observed to lie within an interval instead of being observed exactly, i.e., each observation is an interval and not a single value. This type of data is known as interval-censored. It may arise in questionnaire-based studies when the respondent gives an answer in the form of an interval without having pre-specified ranges. Such data are called self-selected interval data. In this context, the assumption of noninformative censoring is not fulfilled, and therefore the existing methods for interval-censored data are not necessarily applicable.A problem of interest is to estimate the underlying distribution function. There are two main approaches to this problem: (i) parametric estimation, which assumes a particular functional form of the distribution, and (ii) nonparametric estimation, which does not rely on any distributional assumptions. In Paper A, a nonparametric maximum likelihood estimator for self-selected interval data is proposed and its consistency is shown. Paper B suggests a parametric maximum likelihood estimator. The consistency and asymptotic normality of the estimator are proven.Another interesting problem is to infer whether two samples arise from identical distributions. In Paper C, nonparametric two-sample tests suitable for self-selected interval data are suggested and their properties are investigated through simulations.Paper D concerns testing for stochastic dominance with uncensored data. The paper explores a testing problem which involves four hypotheses, that is, based on observations of two random variables X and Y, one wants to discriminate between four possibilities: identical survival functions, stochastic dominance of X over Y, stochastic dominance of Y over X, or crossing survival functions. Permutation-based tests suitable for two independent samples and for paired samples are proposed. The tests are applied to data from an experiment concerning the individual's willingness to pay for a given environmental improvement.
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| 8. |
- Enqvist, Johan, 1982-
(författare)
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Stewardship in an urban world : Civic engagement and human–nature relations in the Anthropocene
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Never before have humans wielded a greater ability to alter and disrupt planetary processes. Our impact is becoming so noticeable that a new geological epoch has been proposed – the Anthropocene – in which Earth systems might no longer maintain the stable and predictable conditions of the past 12 millennia. This is particularly evident in the rapid expansion of urban areas, where a majority of humans now live and where environmental changes such as rising temperatures and habitat loss are happening faster than elsewhere. In light of this, questions have been raised about what a more responsible relationship between humans and the rest of the planet might look like. Scholars in sustainability science employ the concept of ‘stewardship’ in searching for an answer; however, with multiple different applications and definitions, there is a need to better understand what stewardship is or what novelty it might add to sustainability research. This thesis investigates stewardship empirically through two case studies of civic engagement for protecting nature in cities – Bengaluru, India and New York City, USA. Further, the thesis also proposes a conceptual framework for how to understand stewardship as a relation between humans and the rest of nature, based on three dimensions: care, knowledge and agency. This investigation into stewardship in the urban context uses a social–ecological systems approach to guide the use of mixed theory and methods from social and natural sciences. The thesis is organized in five papers. Paper I reviews defining challenges in managing urban social–ecological systems and proposes that these can more effectively be addressed by collaborative networks where public, civic, other actors contribute unique skills and abilities. Paper II and Paper III study water resource governance in Bengaluru, a city that has become dependent on external sources while its own water bodies become degraded and depleted.Paper II analyzes how locally based ‘lake groups’ are able to affect change through co-management arrangements, reversing decades of centralization and neglect of lakes’ role in Bengaluru’s water supply.Paper III uses social–ecological network analysis to analyze how patterns in lake groups’ engagements and collaborations show better fit with ecological connectivity of lakes.Paper IV employs sense of place methods to explore how personal bonds to a site shapes motivation and goals in waterfront stewardship in New York City. Finally,Paper V reviews literature on stewardship and proposes a conceptual framework to understand and relate different uses and underlying epistemological approaches in the field. In summary, this thesis presents an empirically grounded contribution to how stewardship can be understood as a human–nature relation emergent from a deep sense ofcare and responsibility, knowledge and learning about how to understand social–ecological dynamics, and theagency and skills needed to influence these dynamics in a way that benefits a greater community of humans as others. Here, the care dimension is particularly important as an underappreciated aspect of social–ecological relations, and asset for addressing spatial and temporal misalignment between management institutions and ecosystem. This thesis shows that care for nature does not erode just because green spaces are degraded by human activities – which may be crucial for promoting stewardship in the Anthropocene.
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| 9. |
- Grönberg Eskel, Marit, 1971-
(författare)
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Från slutna institutioner till institutionaliserat omhändertagande
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, a number of reforms have been made regarding the provision of care to people experiencing psychiatric disabilities. The aim of these reforms was to enable these people to participate in society and to ”live as others”. This political ambition, as well as research on recovery, stands to a certain extent in contrast to the message conveyed in the media, where the mentally ill/disabled to a great extent are represented as dangerous and incurable. The aim of the thesis is to analyse if, and how a group of people experiencing psychiatric disabilities create a sense of being like others, and to relate the analysis to the historical emergence of the contemporary conception of mental illness/psychiatric disability. This thesis employs the method of interviews.I highlight the informants encounter with the historically based stereotype that defines the persons as unreasonable, irrational and incapable of taking care of themselves. When the informants face the stereotype, they act to reduce the negative consequences. The informants’ actions can be interpreted in terms of approaches and in this perspective the informants appear as strong actors, who, contrary to the stereotype, are capable of take care of themselves. Three approaches are described: expertise, adaptation, and distancing. In situations where the stereotype is not present, the informants can create a feeling of being like anyone else. Their stories show that the feeling of being like others is individual. The development taking place in the field is “path-dependent”, meaning that the initial activity, the differentiation of persons with mental illness and the subsequent events is a development following a pattern which could explain the failure of the good political intentions. It has progressed from closed institutions to an institutionalized care service.
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| 10. |
- Karlsson, Roger
(författare)
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Reflective-functioning during the process and in relation to outcome in cognitive-behavioral therapy, interpersonal psychotherapy and brief psychodynamic
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this work was to investigate reflective-functioning (RF) as a measure of process in two independent studies that included three types of brief psychotherapy. RF is defined as the ability to recognize the existence and nature of mental processes taking place in the self and in others (e.g., intentions, beliefs, desires, and wishes). Theorists have suggested the ability for RF is crucial for predicting social causality and low RF has been found related to mental disorders. It has recently been suggested in the literature that improved ability for RF might be an important component of successful psychotherapy outcome, especially with respect to achieving structuralchange. RF was in this work investigated during the process through discourse analysis of the patients’ narratives of self-other interactions in the treatment sessions. The Psychotherapy Process Q-set (PQS) was implemented in order to isolate specific components of the process (process correlates) that identified high and low RF and to investigate the links between the process correlates and outcome. The first study investigated 29 cases of cognitive-behavioral therapy(CBT) and 35 cases of interpersonal psychotherapy (IPT) with an average treatment length of 16.2 sessions in a sample from the National Institute of Mental Health (NIMH) randomized clinical trial Treatment of Depression Collaborative Research Program (TDCRP). The sample in the first study consisted of 128 sessions in total, were one session from the early part (on average the 4th session) and one session in the later part of the treatment (on average the 12th session) were rated for RF. The second study investigated a sample of 30 cases of brief psychodynamic psychotherapy (BPDT) with an average treatment length of 15.8 sessions in a naturalistic designand obtained from the Mount Zion Psychotherapy Research Group. In total, the second study included 90 sessions of BPDT, and RF was assessed during the 1st, the 5th, and the 14th session of each treatment. The results from these two studies suggested that the patients’ ability for RF, as measured through the discourse from therapy sessions, is stable (in CBT and BPDT) or decreased(IPT) during the treatments. Furthermore, the process correlates defining high RF had a relation with good outcome, and process correlates defining low RF had a relation with poor outcome.The process correlates identified during the PQS-analysis suggested that both high and low RF was linked with personality characteristics in the patients. For example, high RF was linked to patients’ ability for introspection, expression of negative emotions, and commitment to treatment.Low RF was linked to patients’ expression of passivity, defensiveness, and suspiciousness. This work supported theorists’ suggestions that brief treatments are supportive in their nature and therefore do not promote structural changes (e.g., changes in RF). It is suggested that the abilityfor RF as assessed pre-treatment might be a useful predictor for success in brief psychotherapy and could therefore be used as a patient inclusion criteria for such treatments.
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