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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.
21

Ephemeral Architectures: towards a process architecture

Anderson, Charles Nicholas, charles.anderson@rmit.edu.au January 2009 (has links)
This PhD responds to a two fold problem with the philosophy of design and the practice of design. The philosophical problem is stated as the discrepancy between a dominant philosophical framework that orders the world according to eternal essences and the actual conditions of the world in which we exist: the conditions of becoming and of flux. Commencing with a critique of the western metaphysical tradition of statics this research project proposes that we need to find a way of describing an evolutionary model of practice, and by so doing to provide a revitalised narration of process. Consequently, the PhD explores the meanings of process through a critical examination of an ensemble of projects created by the author. Within this framework, a number of questions are posed in order to explore the proposition of a process practice. These questions are: What is process? How does one think process? Indeed, how do we get to grasp change? What are the consequences of process thinking on the practices of design, their fields of operation, and their productions? And, how can the thematising of process contribute to the design of the constructed environment, as well as reconfigure the practices of design? This thematising of process is argued to involve a necessary address to the constitutive and interrelated characteristics of process: space/time, movement, change, form and matter. Such an address is also seen to problematise the status of the object, the paradigms of representation, the modes of creation, the economies of exchange, and the structures of community, and to offer a modality of practice which would re-imagine the forms of social exchange to offer an ethical alternative to the tyranny of supply and demand, and thereby reconfigure the potential for dwelling. Making an overview of the discourses and practices engaging with theories of becoming, this thesis argues that almost all of these re-inscribe statics and that consequently the practice of design seems to drag behind our understanding of the world. Through a meditation on dis/appearance, in which the dynamics of being and becoming and the restless ambiguity of the gap are examined, the work establishes a process vocabulary, and makes clear through a material practice, the domains of process thinking, its inclinations, and the kinds of operations and procedures that flourish there. Foregrounding the fertile character of process practice, the PhD then proceeds to introduce notions of the movement-form, the duration-form, the transformational-form, the geometry of encounter, and to argue for physical form as an in-movement poise. Advocating new modes of approach and of attentiveness, and demonstrating new generative methods, this PhD argues that process thinking is not simply an operational stance, but an ethical position that identifies a field of care, and that consequently the design practices be expanded by taking seriously the relationship between process thinking and place making. Thus, this thesis concludes by advocating a mode of place making which, rather than reproduce planned environments as systems of control, configures place as the discursive contested place of encounter and exchange.
22

Consensus under communication delays

Seuret, Alexandre, Dimarogonas, Dimos V., Johansson, Karl Henrik January 2008 (has links)
This paper deals with the consensus problem under communication network inducing delays. It is well-known that introducing a delay leads in general to a reduction of the performance or to instability due to the fact that timedelay systems are infinite dimensional. For instance, the set of initial conditions of a time-delay system is not a vector but a function taken in an interval. Therefore, investigating the effect of time-delays in the consensus problem is an important issue. In the present paper, we assume that each agent receives instantaneously its own state information but receives the state information from its neighbors after a constant delay. Two stability criteria are provided based on the frequency approach and on Lyapunov-Krasovskii techniques given in terms of LMI. An analytic expression of the consensus equilibrium which depends on the delay and on the initial conditions taken in an interval is derived. The efficiency of the method is tested for different network communication schemes. / <p>QC 20110120</p>
23

Stroj času jako kulečník / Billiard time machine

Dolanský, Jindřich January 2011 (has links)
Title: Billiard time machine Author: Jindřich Dolanský Department: Institute of Theoretical Physics Supervisor: doc. RNDr. Jiří Langer, CSc. Supervisor's e-mail address: Jiri.Langer@mff.cuni.cz Abstract: In this work we investigate a simple interacting system of an elastic particle in the non-relativistic spacetime with a nontrivial causal structure realized by a worm- hole with a time shift. We require that standard local physical laws hold, and search for their globally consistent solutions, i.e, we assume the validity of the principle of self-consistency. If there were nontrivial set of initial conditions which would violate this principle, the system would be logically inconsistent. We show that the investigated system is not inconsistent in this sense, i.e., that all standard initial conditions have a globally consistent evolution. Even for the so called dangerous initial conditions which threaten to result into the paradoxical situation a consistent solution exists. In this case, the paradoxical collision-free trajectory is superseded by a special consistent self-colliding trajectory. Moreover, we demonstrate that more than one globally consistent evolution exists for a wide class of initial conditions. Thus, the evolution of the described system is not unique due to the nontrivial causal structure...

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