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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

An Application Of Cybernetic Principles To The Modeling And Optimization Of Bioreactors

Mandli, Aravinda Reddy 02 1900 (has links) (PDF)
The word cybernetics has its roots in the Greek word \kybernetes" or \steers-man" and was coined by Norbert Wiener in 1948 to describe \the science of control and communication, in the animal and the machine". The discipline focuses on the way various complex systems (animals/machines) steer towards/maintain their goals utilizing information, models and control actions in the face of various disturbances. For a given animal/machine, cybernetics considers all the possible behaviors that the animal/machine can exhibit and then enquires about the constraints that result in a particular behavior. The thesis focuses on the application of principles of cybernetics to the modeling and optimization of bioreactors and lies at the interface of systems engineering and biology. Specifically, it lies at the interface of control theory and the growth behavior exhibited by microorganisms. The hypothesis of the present work is that the principles and tools of control theory can give novel insights into the growth behavior of microorganisms and that the growth behavior exhibited by microorganisms can in turn provide insights for the development of principles and tools of control theory. Mathematical models for the growth of microorganisms such as stoichiometric, optimal and cybernetic assume that microorganisms have evolved to become optimal with respect to certain cellular goals or objectives. Typical cellular goals used in the literature are the maximization of instantaneous/short term objectives such biomass yield, instantaneous growth rate, instantaneous ATP production rate etc. Since microorganisms live in a dynamic world, it is expected that the microorganisms have evolved towards maximizing long term goals. In the literature, it is often assumed that the maximization of a short term cellular goal results in the maximization of the long term cellular goal. However, in the systems engineering literature, it has long been recognized that the maximization of a short term goal does not necessarily result in the maximization of the long term goal. For example, maximization of product production in a fed-batch bioreactor involves two separate phases: a first phase in which the growth of microorganisms is maximized and a second phase in which the production of product is maximized. An analogous situation arises when the bacterium E. coli passes through the digestive tract of mammals wherein it first encounters the sugar lactose in the proximal portions and the sugar maltose in the distal portions. Mitchell et al. (2009) have experimentally shown that when E. coli encounters the sugar lactose, it expresses the genes of maltose operons anticipatorily which reduces its growth rate on lactose. This regulatory strategy of E. coli has been termed asymmetric anticipatory regulation (AAR) and is shown to be beneficial for long term cellular fitness by Mitchell et al. (2009). The cybernetic modeling framework for the growth of microorganisms, developed by Ramakrishna and co-workers, is extended in the present thesis for modeling the AAR strategy of E. coli. The developed model accurately captures the experimental observations of the AAR phenomenon, reveals the inherent advantages of the cybernetic modeling framework over other frameworks in explaining the AAR phenomenon, while at the same time suggesting a scope for the generalization of the cybernetic framework. As cybernetics is interested in all the possible behaviors that a machine (which is, in the present case, microorganism) can exhibit, a rigorous analysis of the optimal dynamic growth behavior of microorganisms under various constraints is carried out next using the methods of optimal control theory. An optimal control problem is formulated using a generalized version of the unstructured Monod model with the objective of maximization of cellular concentration at a fixed final time. Optimal control analysis of the above problem reveals that the long term objective of maximization of cellular concentration at a final time is equivalent to maximization of instantaneous growth rate for the growth of microorganisms under various constraints in a two substrate batch environment. In addition, reformulation of the above optimal control problem together with its necessary conditions of optimality reveals the existence of generalized governing dynamic equations of the structured cybernetic modeling framework. The dynamic behavior of the generalized equations of the cybernetic modeling framework is analyzed further to gain insights into the growth of microorganisms. For growth of microorganisms on a single growth limiting carbon substrate, the analysis reveals that the cybernetic model exhibits linear growth behavior, similar to that of the unstructured Contois model at high cellular concentrations, under appropriate constraints. During the growth of microorganisms on multiple substitutable substrates, the analysis reveals the existence of simple correlations that quantitatively predict the mixed substrate maximum specific growth rate from single substrate maximum specific growth rates during simultaneous consumption of the substrates in several cases. Further analysis of the cybernetic model of the growth of S. cerevisiae on the mixture of glucose and galactose reveals that S. cerevisiae exhibits sub-optimal dynamic growth with a long diauxic lag phase and suggests the possibility for S. cerevisiae to grow optimally with a significantly reduced diauxic lag period. Since cybernetics is interested in understanding the constraints under which a particular machine (microorganism) exhibits a particular behavior, a methodology is then developed for inferring the internal constraints experienced by the microorganisms from experimental data. The methodology is used for inferring the internal constraints experienced by E. coli during its growth on the mixture of glycerol and lactose. An interesting question in the study of the growth behavior of microorganisms concerns the objective that the microorganisms optimize. Several studies aim to determine these cellular objectives experimentally. A similar question that is relevant to the optimization of fed-batch bioreactors is \what are the objectives that are to be optimized by the feed flow rate in various time intervals for the optimization of a final objective?" It was mentioned previously that the maximization of product production in a fed-batch bioreactor involves maximization of growth of microorganisms first and the maximization of product production later. However, such guidelines can only be stated for relatively simple bioreactor optimization problems and no such guidelines exist for sufficiently complex problems. For complex problems, the answer to the above question requires the formulation and solution of a genetic programming problem which can be quite challenging. An alternative numerical solution methodology is developed in the present thesis to address the above question. The solution methodology involves the specification of bioreactor objectives in terms of the bioreactor trajectory in the state space of substrate concentration-volume. The equivalent control law of the sliding mode control technique is used for finding the inlet feed ow rate that tracks the bioreactor trajectory accurately. The search for the best bioreactor trajectory is carried out using the stochastic search technique genetic algorithm. The effectiveness of the developed solution methodology in determining the optimal bioreactor trajectory is demonstrated using three challenging bioreactor optimization problems.
222

Kybernetika a informační gramotnost / Cybernetics and information literacy

Procházková, Petra January 2012 (has links)
Diploma thesis focuses on cybernetics and information literacy with emphasis on the human element in these topics. The first part describes cybernetics with its two basic terms, which are information and management, as a theoretical resource for subsequent detection of information, resp. internet literacy among students of high scholls and universities. The practical part includes creation of questionnaire, articulation of hypotheses for factual and perceived level of information literacy and subsequent interpretation results of the questionnaire. Addressing the respondents was held by deputy director of one prague high school, through social networks and also by direct addressing. This part reports the information about the level of information literacy with sense of constraints that results contains. Explanatory power of the results of the questionnaire survey is mentioned in the conclusion of this thesis.
223

Imagining information: the uses of storytelling

Higgins, Stefan 13 January 2021 (has links)
This thesis investigates a cultural logic of information. In a world saturated with information, how is representation defined, and what kinds of boundaries does it consequently set up for establishing what can be known? I argue that a cultural logic of information articulates a common cultural definition for representation: information is understood as either a “true” representation of reality, or a substitute for reality itself. As a result, information comes to be conflated with knowledge. But, in contrast to calls (scholarly and otherwise) to police the boundaries of information, I argue 1) that information is exceedingly difficult to separate, in kind, from storytelling, because 2) the provision of information almost always entails scrambles for narrative representation, which 3) are always staged in the terms of genre. The function of these conclusions is the constant undermining of this cultural logic. I examine the intersection of a variety of cultural and theoretical objects, including: Fox News and “Make America Great Again”; scientific modelling of climate change; Claude Shannon’s mathematical theory of communication; Karl Ove Knausgaard’s My Struggle; YouTube “lifestyle” communities; and the documentary “The Act of Killing.” I suggest that a methodology that accounts for the imbrication of information and storytelling better accounts for the vicissitudes of, and ideological struggles over, these cultural phenomena. It does so, in particular, by engaging with the subjective experience of information, and assessing how subjects imagine their relations to information and to networks. The purpose of this argument is to intervene in conversations about the articulation of life in control societies. / Graduate / 2021-06-20
224

Urban Planning & Governance in the Age of AI : A Study of the Potential Benefits and Risks / Stadsplanering och styrning i AI-tidsåldern : En studie om potentiella fördelar och risker

Gummesson, Jonas January 2023 (has links)
Artificial intelligence (AI) is a rapidly developing technology which in this project refers to software that given objectives generate content, predictions, recommendations, or decisions influencing their environment. Using literature reviews and semi-structured interviews, the current and future uses, sentiments, regulations, and risks of AI in urban planning and governance are gathered. While current uses are few, the potential capabilities range from highly complex and large-scale, to small-scale and routine tasks. These tasks include smart resource management, predictive analysis, digital personal assistance, intelligent data processing, and visualization and recommendation. The general goal is to better reinvest human time and effort, for instance in providing meaningful citizen interactions. A lack of good governance and regulation of AI could permit profit-driven technology companies to control the discourse, possibly contributing to issues of public trust, lack of transparency and accountability, inequality, and public participation. Organisations and nations including the UN, EU, and Sweden have formulated strategies for AI, and the EU is currently developing the first regulatory framework for AI facilitating the protection of good operation, design, inclusivity, and privacy of the systems. Further research and debate on this topic is needed to ensure that AI is developed, implemented, and used ethically and responsibly. / Artificiell intelligens (AI) är en snabbt utvecklande teknologi som i detta projekt avser programvara som med givna mål genererar innehåll, förutsägelser, rekommendationer eller beslut som påverkar dess omgivning. Genom litteraturöversikter och semistrukturerade intervjuer har de aktuella och framtida användningsområdena, åsikterna, regleringarna och riskerna med AI inom stadsplanering och styrning samlats in. Trots att de nuvarande användningsområdena är få sträcker sig de potentiella förmågorna från mycket komplexa och storskaliga till småskaliga rutinuppgifter. Dessa uppgifter inkluderar smart resurshantering, prediktiv analys, digital personlig assistans, intelligent databehandling samt visualisering och rekommendation. Det övergripande målet är att investera mänsklig tid och ansträngning på ett bättre sätt, exempelvis genom att erbjuda meningsfulla interaktioner med medborgare. En brist på god styrning och reglering av AI skulle kunna tillåta vinstdrivna teknikföretag att kontrollera diskursen, vilket kan leda till problem med allmänhetens förtroende, brist på transparens och ansvar, ojämlikhet och offentlig delaktighet. Organisationer och nationer inklusive FN, EU och Sverige har formulerat strategier för AI, och EU utvecklar för närvarande det första regelverket för AI för att underlätta god drift, utformning, inkludering och integritet hos systemen. Ytterligare forskning och debatt om detta ämne behövs för att säkerställa att AI utvecklas, implementeras och används på ett etiskt och ansvarsfullt sätt
225

The Politics of Conspiracy Theory and Control: Cybernetic Governmentality and the Scripted Political

Beckenhauer, Samuel Brian 13 May 2024 (has links)
This study analyzes the politics of contemporary conspiracy theory discourses in the United States. Departing from the predominant methodological individualism that characterizes many contemporary analyses of conspiracy theory, which take the individual subject as the unit to be explained and governed, this study situates the production and proliferation of conspiracy theory discourses in the context of cybernetics and related transformations in politics that have tended to reduce democratic representativeness and increase forms of economic and political inequality. Cybernetics, which is often defined as the science of command and control, offers a series of concepts that facilitate an understanding of how freedom and control have become aligned in the second half of the 20th and early 21st centuries in the United States. I utilize Michel Foucault's governmentality approach to formulate a cybernetic governmentality methodology, which analyzes the governance of subjectivity in and through cybernetic systems of communication. Cybernetics, which seeks to invite the individual subject to realize itself through 'choice' and by way of its imbrication into machinic systems, conceptualizes the subject as a consumer and processor of information. I put forth the notion of the scripted political to analyze a key tension within contemporary U.S. politics, as politics is becoming increasingly uncertain yet also often appears to be strongly controlled by political and economic elites. Conspiracy theory, as a speculative genre of thinking, aims to steer events towards certain political ends. Conspiratorial speculation has become a popular means to connect and reflect on a felt obsolescence or superfluity on the part of the individual subject. To substantiate these arguments, I specifically analyze the discourses of QAnon and Covid-19 conspiracy theories. These discourses express political fantasies that often privilege the idea of a liberal autonomous individual subject. The politics of contemporary conspiracy theory in the United States thus concerns the fact that these conspiratorial discourses seek to perform a form of liberal subjectivity. However, this performance of individual liberal subjectivity is always caught in cybernetic systems of communication, which seek to produce value, harvest data, and maximize the attention of their 'users', thus undermining the potential for any meaningful form of liberal subjectivity. / Doctor of Philosophy / This study analyzes the politics of contemporary conspiracy theory discourses in the United States. Whereas today many scholars approach conspiracy theory as concerning the beliefs of individual subjects, whose thoughts are considered deviant and potentially requiring reform or monitoring, this study engages with conspiracy theory discourses and their conditions of possibility. While many acknowledge that conspiracy theory is a response to a felt loss of control, this notion of control is understood to be only potentially true or valid. Cybernetics, which is often defined as the science of command and control, offers a series of concepts that facilitate an understanding of how freedom and control have become aligned in the second half of the 20th and early 21st centuries in the United States. Cybernetics, which seeks to invite the individual subject to realize itself through 'choice' and by way of its imbrication into machinic and technological systems, conceptualizes the individual subject as a consumer and processor of information. I develop a new notion that I call the scripted political to study a key tension within contemporary U.S. politics, as politics is becoming increasingly uncertain yet also often appears to be strongly controlled by political and economic elites. Conspiracy theory is a speculative genre of thinking that is well-suited to produce social and political meaning in a condition of information saturation characteristic of today's social domain. It does so, among other things, by providing explanations about the operations of what many conspiracy theorists consider to be concentrated forms of power and by attempting to steer events towards certain desirable political ends. However, as a way of producing social and political meaning, conspiracy theory often misses the mark. Yet, despite its frequent factual inconsistencies, conspiratorial discourses and speculations have become popular means to create social connections and to reflect on a sense of obsolescence or superfluity felt by many individual subjects. To support these arguments, I focus on the conspiratorial discourses of and about QAnon and about the Covid-19 pandemic. These discourses express political fantasies that often privilege the idea of a liberal autonomous individual subject. However, I show in this study that fantasies about a re-empowered mode of individual liberal subjectivity are often caught in cybernetic systems of communication, which are more interested in producing economic value, harvesting all sorts of data about individual subjects, and maximizing the attention of their 'users', thus undermining the potential for any return to a meaningful form of liberal subjectivity.
226

Ein Dialog zwischen Managementlehre und Alttestamenlicher Theologie: McGregors Theorien X und Y zur Führung im lichte alttestamentlicher Anthropologie

Kessler, Volker 30 September 2004 (has links)
Text in German / This dissertation is a contribution to cybernetics, a sub-discipline ofPractical Theology. It is a dialogue between theology and management science. The first part discusses whether such a dialogue is reasonable at all. There are a lot of parallels between wisdom theology in the Old Testament and modern management theory. We discuss the benefits and the limitations of wisdom, and the way Israel took advantage of wisdom knowledge of the surrounding peoples. Finally, we draw conclusions for the way how church leadership could integrate knowledge from management theory. The main part of this dissertation is on anthropology and leadership. McGregor invented 1957/60 the so-called theories X andY. He demonstrated that leadership styles of managers are affected by the way they look at their subordinates. Leaders who regard people as lazy (theory X) will try to movitate people by extrinsic factors. Theory Y assumes that human beings have intrinsic motives to work. This assumption is an implicit basis of modem leadership concepts. The background and influence of these theories are explained. Especially, we follow the way from the anthropology of the reformators to theory X and from theory X (Taylorism) to theory Y. Limitations of theory Y are also discussed. In the next step we describe various facets of Old Testament anthropology dealing with man's willingness and capacity to work. The significance of the imago dei in this context is discussed by and large. Finally, we compare these facets with the theories X and Y. Result: The reformators emphasized one-sidedly the undignity of human beings implying that many Protestants consider theory Y as too positive, too humanistic. Old Testament portrays both the dignity and the undignity of human beings. Old Testament anthropology correlates better with theory Y. Thus theory Y is not an antibiblical theory. / Practical Theology / D.Th (Practical Theology)
227

The making of a champion : a constructed reality

Gaddie, Toni 08 1900 (has links)
This dissertation explores the construction and experience of the sports champion's reality. In studying reality and its construction, I became familiar with, the post-modern perspective of reality and with theories such as systems theory, cybernetics, radical constructivism and social constructionism, which fall under the post-modern epistemological umbrella. The dissertation gives an exposition of my journey through this maze of theories, from a position of "knowing" how champions are made towards a more complex position of uncertainty and possibility. This is followed by an account of the qualitative research that I undertook, within a social constructionist framework, in which I used thematic discourse analysis. Finally, I interpret the discourses emerging from the analysis in order to demonstrate their operation or effect in the construction of a champion's reality. / Psychology / M.A. (Clinical Psychology)
228

A symptom as part of a recursive process of interaction in a black family

Mashiane, Selema 03 1900 (has links)
This study is an endeavour to demonstrate the applicability of constructivist epistemology in different contexts. The black family is presented as one of such contexts. The study is further a demonstration of the role of a symptom as part of a recursive process of interaction in the context of a black family. It reflects an orientation rooted in cybernetics, ecology and systems theory. Therapy is presented as a context through which the therapist becomes incorporated and, therefore, adopting and speaking the language of the family's particular form of symptomatic communication in order to engender change. A literature study presenting a conceptual framework is presented. A case study presenting the research data is presented. Transcripts from video-taped sessions with the family are presented in the addendum. The implications of constructivist framework for the field of family therapy in the context of a black family are, therefore, outlined. / Social work / M.A. (Mental Health)
229

Delinquent gangs in context : towards an ecology of meaning

Venter, Anneri 03 1900 (has links)
Gangs exist as metaphors of the societies in which they are embedded and are powerful, hence the need is great for an ecologically powerful model and a collation of a picture about gangs and gang life as described by knowledgeable individuals. With so much literature and knowledgeable individuals at hand to provide insight into the problem, the rationale for this study comes forth in the form of taking all this knowledge and insight and creating a collation of a picture of gangs as it is understood by those who study them and by those who have been confronted with them. The theoretical framework is a social constructionist cybernetic epistemology. One-on-one interviews were conducted with knowledgeable sources and audio-visual material assisted in understanding the context of gangs better. A hermeneutic analysis was used. The interview transcripts from the participants were analysed and themed according to a thematic network analysis and linked with available literature. These themes were then used to represent a Time Cable of gangs. / Psychology / M.A. (Psychology)
230

Chronic headache : an ecosystemic exploration

Rawsthorne, Julie Karen 12 1900 (has links)
Chronic headache may be the most frequently reported somatic symptom, yet it puzzles health experts and poses a considerable treatment challenge. It was suggested that this is because conventional views of headache, adhering to a Newtonian-Cartesian epistemology, focus almost exclusively on intrapsychic factors ignoring the wider social context in which the problem is embedded. An overview of the existing body of knowledge on the most widely researched headache conditions was presented, and it was argued that a conceptual shift is required to achieve a more comprehensive understanding of the problem. This study was conducted within an holistic, ecosystemic epistemology. A qualitative approach employing a case study method was adopted to provide rich descriptions of the contexts in which two chronic headache sufferers' symptoms were embedded. The case study presentations also illustrated the attempts that were made to intervene into the headache contexts from a second-order cybernetics stance. / Psychology / M.A. (Clinical Psychology)

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