Extension et analyse des schémas de Boltzmann sur réseau

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (899 download)

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Book Synopsis Extension et analyse des schémas de Boltzmann sur réseau by : Tony Février

Download or read book Extension et analyse des schémas de Boltzmann sur réseau written by Tony Février and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse introduit et étudie une nouvelle classe de schémas de Boltzmann sur réseau appelés schémas à vitesse relative. Les schémas de Boltzmann sur réseau visent à approcher des problèmes de nature macroscopique en mimant la dynamique microscopique d'équations cinétiques du type Boltzmann. L'algorithme calcule des distributions de particules évoluant au travers de deux phases de transport et de relaxation, les particules se déplaçant en les noeuds d'un réseau cartésien en espace. Les schémas de Boltzmann à plusieurs temps de relaxation (ou schéma MRT de d'Humières), dont la relaxation im- plique un ensemble de moments combinaison linéaire polynomiale des distributions, constituent le cadre initial de la thèse. Les schémas à vitesse relative sont une extension de ces schémas de d'Humières. Ils sont inspirés du schéma cascade de Geier apportant davantage de stabilité que les schémas de d'Hu- mières pour des régimes peu visqueux des équations de Navier-Stokes. La différence avec ces schémas se situe au niveau de la relaxation : elle utilise un ensemble de moments relatifs à un paramètre champ de vitesse fonction du temps et de l'espace. Cette différence se matérialise par une matrice de tran- sition des moments fixes (les schémas de d'Humières correspondent à un paramètre champ de vitesse nul) aux moments mobiles. La structure algébrique de cette matrice est étudiée. Le schéma cascade est ensuite traduit comme un schéma à vitesse relative pour un nouvel ensemble de polynômes définissant les moments. L'étude de la consistance des schémas à vitesse relative par la méthode des équations équivalentes est un point central de la thèse. Les équations limites pour un nombre arbitraire de dimen- sions et de vitesses sont dérivées et illustrées sur des exemples tels que le D2Q9 pour les équations de Navier-Stokes. Ces équations équivalentes sont également un outil pour prédire la stabilité des schémas grâce à l'analyse des termes de diffusion et dispersion. La dernière partie traite de la stabilité suivant le choix du paramètre champ de vitesse. Nous sommes particulièrement intéressés en les deux choix de paramètre nul (d'Humières) et la vitesse du fluide (cascade). Le schéma D2Q9 pour les équations de Navier-Stokes est étudié numériquement par une méthode de Von Neumann puis appuyé sur des cas tests non linéaires. La stabilité des schémas relatifs à la vitesse du fluide est dépendante du choix des polynômes définissant les moments. L'amélioration la plus notable se produit si les polynômes du schéma cascade sont choisis. Nous étudions enfin les stabilités théorique et numérique d'un schéma bidimensionnel minimal. Le contexte physique est la simulation d'une équation d'advection diffusion linéaire. Le choix de la vitesse d'advection comme paramètre champ de vitesse annule certains termes de dispersion des équations équivalentes contrairement aux schémas de d'Humières. Ceci se traduit par un meilleur comportement en termes de stabilité pour de grandes vitesses, appuyé théoriquement à l'aide d'une notion de stabilité à poids.

Identification de modèles et de paramètres pour la méthode de Boltzmann sur réseau

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ISBN 13 :
Total Pages : 147 pages
Book Rating : 4.:/5 (494 download)

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Book Synopsis Identification de modèles et de paramètres pour la méthode de Boltzmann sur réseau by : Mohamed-Mahdi Tekitek

Download or read book Identification de modèles et de paramètres pour la méthode de Boltzmann sur réseau written by Mohamed-Mahdi Tekitek and published by . This book was released on 2007 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse comporte trois parties: étude du schéma de Boltzmann sur réseau, schéma adjoint de Boltzmann sur réseau pour l'identification de paramètres et construction d'une couche parfaitement absorbante pour ce schéma. La première partie introduit et analyse la méthode. La deuxième partie décrit une approche variationnelle pour l'assimilation de paramètres relatifs à la méthode du gaz de Boltzmann sur réseau. Une méthode adjointe discrète en temps est développée. L'algorithme est d'abord testé sur un écoulement de type Poiseuille linéaire (problème de Stokes), puis il est appliqué à un problème non linéaire. Des résultats encourageants sont obtenus pour un et deux paramètres inconnus. Finalement la troisième partie décrit une adaptation des couches absorbantes de Bérenger. Il en résulte un modèle d'automate de Boltzmann à neuf vitesses discrètes. Une analyse des ondes réfléchies est ensuite réalisée entre deux milieux de Boltzmann à une dimension, ce qui permet d'obtenir un équivalent des formules de Fresnel pour les schémas de Boltzmann et de proposer des modifications du schéma à l'interface pour annuler les ondes réfléchies. En deux dimensions, la même analyse d'ondes réfléchies met en évidence l'apparition de modes de Knudsen et des ondes transverses qui rendent l'analyse complexe.

Stabilité linéaire et non linéaire des schémas de Boltzmann sur réseau simulant des écoulements visqueux compressibles

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (98 download)

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Book Synopsis Stabilité linéaire et non linéaire des schémas de Boltzmann sur réseau simulant des écoulements visqueux compressibles by : Louis-Marie Cleon

Download or read book Stabilité linéaire et non linéaire des schémas de Boltzmann sur réseau simulant des écoulements visqueux compressibles written by Louis-Marie Cleon and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'étude de stabilité des systèmes différentiels issus des équations de Navier-Stokes consiste à analyser la réponse du système linéarisé à une perturbation en onde plane. Elle ne peut pas rendre compte de tous les mécanismes possibles d'instabilité non linéaire. De telles analyses de stabilité non linéaire ont été abordées pour des discrétisations en différences finies de l'équation scalaire non visqueuse de Burgers. Elles sont basées sur l'analyse en ondes résonantes, en considérant un ensemble d'ondes qui forment un groupe fermé pour l'équation discrétisée. Une conclusion importante de ces travaux est que quelques mécanismes non linéaires instables existent qui échappent à l'analyse linéaire, comme le mécanisme de focalisation étudié et expliqué à l'aide des modes de side band, introduits pour amorcer les instabilités. Cette approche d'ondes résonantes est étendue à l'analyse non linéaire de stabilité pour les méthodes LBM (Lattice Boltzmann Method). Nous présentons pour la première fois une équation vectorielle à la place de l' équation scalaire de Burgers, car la méthode LBM considère une fonction de distribution par vitesses discrètes. L'application du principe des ondes résonantes aux équations de Boltzmann sur réseau pour un écoulement monodimensionnel, compressible et isotherme dans un schéma D1Q3 donne des cartes d'instabilité, dans le cas de 1 ou plusieurs modes résonants, très dépendantes des conditions initiales. Le phénomène de focalisation n'a pas été obtenu dans la formulation LBM. Des croissances transitoires dues à la non-normalité des opérateurs peuvent exister. Elles sont calculées par une méthode d'optimisation Lagrangienne utilisant les équations adjointes de LBM. L'application du principe des ondes résonantes est étendue à un modèle 2D. On montre que les instabilités deviennent prépondérantes.

Vortex Methods

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Publisher : Cambridge University Press
ISBN 13 : 9780521061704
Total Pages : 0 pages
Book Rating : 4.0/5 (617 download)

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Book Synopsis Vortex Methods by : Georges-Henri Cottet

Download or read book Vortex Methods written by Georges-Henri Cottet and published by Cambridge University Press. This book was released on 2008-04-24 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex methods have matured in recent years, offering an interesting alternative to finite difference and spectral methods for high resolution numerical solutions of the Navier Stokes equations. In the past three decades, research into the numerical analysis aspects of vortex methods has provided a solid mathematical background for understanding the accuracy and stability of the method. At the same time vortex methods retain their appealing physical character, which was the motivation for their introduction. This book presents and analyzes vortex methods as a tool for the direct numerical simulation of impressible viscous flows. It will interest graduate students and researchers in numerical analysis and fluid mechanics and also serve as an ideal textbook for courses in fluid dynamics.

The Constitution of Algorithms

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Publisher : MIT Press
ISBN 13 : 0262542145
Total Pages : 401 pages
Book Rating : 4.2/5 (625 download)

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Book Synopsis The Constitution of Algorithms by : Florian Jaton

Download or read book The Constitution of Algorithms written by Florian Jaton and published by MIT Press. This book was released on 2021-04-27 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: A laboratory study that investigates how algorithms come into existence. Algorithms--often associated with the terms big data, machine learning, or artificial intelligence--underlie the technologies we use every day, and disputes over the consequences, actual or potential, of new algorithms arise regularly. In this book, Florian Jaton offers a new way to study computerized methods, providing an account of where algorithms come from and how they are constituted, investigating the practical activities by which algorithms are progressively assembled rather than what they may suggest or require once they are assembled.

Navier-Stokes-Fourier Equations

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Publisher : Springer Science & Business Media
ISBN 13 : 3642207456
Total Pages : 283 pages
Book Rating : 4.6/5 (422 download)

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Book Synopsis Navier-Stokes-Fourier Equations by : Radyadour Kh. Zeytounian

Download or read book Navier-Stokes-Fourier Equations written by Radyadour Kh. Zeytounian and published by Springer Science & Business Media. This book was released on 2012-01-26 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research monograph deals with a modeling theory of the system of Navier-Stokes-Fourier equations for a Newtonian fluid governing a compressible viscous and heat conducting flows. The main objective is threefold. First , to 'deconstruct' this Navier-Stokes-Fourier system in order to unify the puzzle of the various partial simplified approximate models used in Newtonian Classical Fluid Dynamics and this, first facet, have obviously a challenging approach and a very important pedagogic impact on the university education. The second facet of the main objective is to outline a rational consistent asymptotic/mathematical theory of the of fluid flows modeling on the basis of a typical Navier-Stokes-Fourier initial and boundary value problem. The third facet is devoted to an illustration of our rational asymptotic/mathematical modeling theory for various technological and geophysical stiff problems from: aerodynamics, thermal and thermocapillary convections and also meteofluid dynamics.

The Neganthropocene

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Publisher : Saint Philip Street Press
ISBN 13 : 9781013290596
Total Pages : 344 pages
Book Rating : 4.2/5 (95 download)

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Book Synopsis The Neganthropocene by : Daniel Ross

Download or read book The Neganthropocene written by Daniel Ross and published by Saint Philip Street Press. This book was released on 2020-10-09 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the essays and lectures here titled Neganthropocene, Stiegler opens an entirely new front moving beyond the dead-end "banality" of the Anthropocene. Stiegler stakes out a battleplan to proceed beyond, indeed shrugging off, the fulfillment of nihilism that the era of climate chaos ushers in. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.

Science and Empires

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Publisher : Springer Science & Business Media
ISBN 13 : 9401125945
Total Pages : 419 pages
Book Rating : 4.4/5 (11 download)

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Book Synopsis Science and Empires by : P. Petitjean

Download or read book Science and Empires written by P. Petitjean and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: SCIENCE AND EMPIRES: FROM THE INTERNATIONAL COLLOQUIUM TO THE BOOK Patrick PETITJEAN, Catherine JAMI and Anne Marie MOULIN The International Colloquium "Science and Empires - Historical Studies about Scientific De velopment and European Expansion" is the product of an International Colloquium, "Sciences and Empires - A Comparative History of Scien tific Exchanges: European Expansion and Scientific Development in Asian, African, American and Oceanian Countries". Organized by the REHSEIS group (Research on Epistemology and History of Exact Sciences and Scientific Institutions) of CNRS (National Center for Scientific Research), the colloquium was held from 3 to 6 April 1990 in the UNESCO building in Paris. This colloquium was an idea of Professor Roshdi Rashed who initiated this field of studies in France some years ago, and proposed "Sciences and Empires" as one of the main research programmes for the The project to organize such a colloquium was a bit REHSEIS group. of a gamble. Its subject, reflected in the title "Sciences and Empires", is not a currently-accepted sub-discipline of the history of science; rather, it refers to a set of questions which found autonomy only recently. The terminology was strongly debated by the participants and, as is frequently suggested in this book, awaits fuller clarification.

Networking for Digital Preservation

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Publisher : Walter de Gruyter
ISBN 13 : 9783598218477
Total Pages : 280 pages
Book Rating : 4.2/5 (184 download)

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Book Synopsis Networking for Digital Preservation by : Ingeborg Verheul

Download or read book Networking for Digital Preservation written by Ingeborg Verheul and published by Walter de Gruyter. This book was released on 2006 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: General Analysis; Digital Repository; Preservation Strategies; Current Activities; Conclusion.

FPGA Implementations of Neural Networks

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Publisher : Springer Science & Business Media
ISBN 13 : 0387284877
Total Pages : 365 pages
Book Rating : 4.3/5 (872 download)

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Book Synopsis FPGA Implementations of Neural Networks by : Amos R. Omondi

Download or read book FPGA Implementations of Neural Networks written by Amos R. Omondi and published by Springer Science & Business Media. This book was released on 2006-10-04 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the 1980s and early 1990s there was signi?cant work in the design and implementation of hardware neurocomputers. Nevertheless, most of these efforts may be judged to have been unsuccessful: at no time have have ha- ware neurocomputers been in wide use. This lack of success may be largely attributed to the fact that earlier work was almost entirely aimed at developing custom neurocomputers, based on ASIC technology, but for such niche - eas this technology was never suf?ciently developed or competitive enough to justify large-scale adoption. On the other hand, gate-arrays of the period m- tioned were never large enough nor fast enough for serious arti?cial-neur- network (ANN) applications. But technology has now improved: the capacity and performance of current FPGAs are such that they present a much more realistic alternative. Consequently neurocomputers based on FPGAs are now a much more practical proposition than they have been in the past. This book summarizes some work towards this goal and consists of 12 papers that were selected, after review, from a number of submissions. The book is nominally divided into three parts: Chapters 1 through 4 deal with foundational issues; Chapters 5 through 11 deal with a variety of implementations; and Chapter 12 looks at the lessons learned from a large-scale project and also reconsiders design issues in light of current and future technology.

Micropolar Fluids

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Publisher : Springer Science & Business Media
ISBN 13 : 1461206413
Total Pages : 262 pages
Book Rating : 4.4/5 (612 download)

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Book Synopsis Micropolar Fluids by : Grzegorz Lukaszewicz

Download or read book Micropolar Fluids written by Grzegorz Lukaszewicz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micropolar fluids are fluids with microstructure. They belong to a class of fluids with nonsymmetric stress tensor that we shall call polar fluids, and include, as a special case, the well-established Navier-Stokes model of classical fluids that we shall call ordinary fluids. Physically, micropolar fluids may represent fluids consisting of rigid, randomly oriented (or spherical) particles suspended in a viscous medium, where the deformation of fluid particles is ignored. The model of micropolar fluids introduced in [65] by C. A. Eringen is worth studying as a very well balanced one. First, it is a well-founded and significant generalization of the classical Navier-Stokes model, covering, both in theory and applications, many more phenomena than the classical one. Moreover, it is elegant and not too complicated, in other words, man ageable to both mathematicians who study its theory and physicists and engineers who apply it. The main aim of this book is to present the theory of micropolar fluids, in particular its mathematical theory, to a wide range of readers. The book also presents two applications of micropolar fluids, one in the theory of lubrication and the other in the theory of porous media, as well as several exact solutions of particular problems and a numerical method. We took pains to make the presentation both clear and uniform.

Basic Concepts for Simple and Complex Liquids

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Publisher : Cambridge University Press
ISBN 13 : 9780521789530
Total Pages : 410 pages
Book Rating : 4.7/5 (895 download)

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Book Synopsis Basic Concepts for Simple and Complex Liquids by : Jean-Louis Barrat

Download or read book Basic Concepts for Simple and Complex Liquids written by Jean-Louis Barrat and published by Cambridge University Press. This book was released on 2003-03-27 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presenting a unified approach, this book focusses on the concepts and theoretical methods that are necessary for an understanding of the physics and chemistry of the fluid state. The authors do not attempt to cover the whole field in an encyclopedic manner. Instead, important ideas are presented in a concise and rigorous style, and illustrated with examples from both simple molecular liquids and more complex soft condensed matter systems such as polymers, colloids, and liquid crystals.

Discharge in Long Air Gaps

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Publisher : IOP Publishing Limited
ISBN 13 : 9780750312370
Total Pages : 0 pages
Book Rating : 4.3/5 (123 download)

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Book Synopsis Discharge in Long Air Gaps by : Abderrahmane Beroual

Download or read book Discharge in Long Air Gaps written by Abderrahmane Beroual and published by IOP Publishing Limited. This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Discharge in Long Air Gaps' presents self-consistent predictive dynamic models of positive and negative discharges in long air gaps. Equivalent models are also derived to predict lightning parameters based on the similarities between long air gap discharges and lightning flashes. Comparisons between computed and experimental results for various test configurations are presented and discussed.

Integrable Systems

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Publisher : Springer Science & Business Media
ISBN 13 : 1461203155
Total Pages : 368 pages
Book Rating : 4.4/5 (612 download)

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Book Synopsis Integrable Systems by : V. Babelon

Download or read book Integrable Systems written by V. Babelon and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the proceedings of the International Conference on Integrable Systems in memory of J.-L. Verdier. It was held on July 1-5, 1991 at the Centre International de Recherches Mathematiques (C.I.R.M.) at Luminy, near Marseille (France). This collection of articles, covering many aspects of the theory of integrable Hamiltonian systems, both finite and infinite-dimensional, with an emphasis on the algebro-geometric meth ods, is published here as a tribute to Verdier who had planned this confer ence before his death in 1989 and whose active involvement with this topic brought integrable systems to the fore as a subject for active research in France. The death of Verdier and his wife on August 25, 1989, in a car accident near their country house, was a shock to all of us who were acquainted with them, and was very deeply felt in the mathematics community. We knew of no better way to honor Verdier's memory than to proceed with both the School on Integrable Systems at the C.I.M.P.A. (Centre International de Mathematiques Pures et Appliquees in Nice), and the Conference on the same theme that was to follow it, as he himself had planned them.

The Reality of the Unobservable

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Publisher : Springer Science & Business Media
ISBN 13 : 9401593914
Total Pages : 368 pages
Book Rating : 4.4/5 (15 download)

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Book Synopsis The Reality of the Unobservable by : E. Agazzi

Download or read book The Reality of the Unobservable written by E. Agazzi and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observability and Scientific Realism It is commonly thought that the birth of modern natural science was made possible by an intellectual shift from a mainly abstract and specuJative conception of the world to a carefully elaborated image based on observations. There is some grain of truth in this claim, but this grain depends very much on what one takes observation to be. In the philosophy of science of our century, observation has been practically equated with sense perception. This is understandable if we think of the attitude of radical empiricism that inspired Ernst Mach and the philosophers of the Vienna Circle, who powerfully influenced our century's philosophy of science. However, this was not the atti tude of the f ounders of modern science: Galileo, f or example, expressed in a f amous passage of the Assayer the conviction that perceptual features of the world are merely subjective, and are produced in the 'anima!' by the motion and impacts of unobservable particles that are endowed uniquely with mathematically expressible properties, and which are therefore the real features of the world. Moreover, on other occasions, when defending the Copernican theory, he explicitly remarked that in admitting that the Sun is static and the Earth turns on its own axis, 'reason must do violence to the sense' , and that it is thanks to this violence that one can know the tme constitution of the universe.

Nanjing Lectures (2016-2019)

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Publisher :
ISBN 13 : 9781013295379
Total Pages : 382 pages
Book Rating : 4.2/5 (953 download)

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Book Synopsis Nanjing Lectures (2016-2019) by : Daniel Ross

Download or read book Nanjing Lectures (2016-2019) written by Daniel Ross and published by . This book was released on 2020-10-09 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this series of lectures, delivered at Nanjing University from 2016 to 2019, Bernard Stiegler rethinks the so-called Anthropocene in relation to philosophy's failure to reckon with the manifold and indeed "cosmic" consequences of the entropic and thermodynamic revolution. Beginning with the Oxford Dictionaries' decision to make "post-truth" the 2016 word of the year, and taking this as an opportunity to understand the implications for Heidegger's "history of being", "history of truth" and Gestell, the first series of lectures enter into an original consideration of the relationship between Socrates and Plato (and of tragic Greece in general) and its meaning for the history of Western philosophy. The following year's lecture series traverse a path from Foucault's biopower to psychopower to neuropower, and then to a critique of neuroeconomics. Revising Husserl's account of retention to focus on the irreducible connection between human memory and technological memory, the lectures culminate in reflections on the significance of neurotechnology in platform capitalism. The concept of hyper-matter is introduced in the lectures of 2019 as requisite for an epistemology that escapes the trap of opposing the material and the ideal in order to respond to the need for a new critique of the notion of information and technological performativity (of which Moore's law both is and is not an example) in an age when the biosphere has become a technosphere. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.

UCRL.

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Publisher :
ISBN 13 :
Total Pages : 26 pages
Book Rating : 4.E/5 ( download)

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Book Synopsis UCRL. by : U.S. Atomic Energy Commission

Download or read book UCRL. written by U.S. Atomic Energy Commission and published by . This book was released on 19?? with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: