149,220 research outputs found
The concept of strong and weak virtual reality
We approach the virtual reality phenomenon by studying its relationship to
set theory, and we investigate the case where this is done using the
wellfoundedness property of sets. Our hypothesis is that non-wellfounded sets
(hypersets) give rise to a different quality of virtual reality than do
familiar wellfounded sets. We initially provide an alternative approach to
virtual reality based on Sommerhoff's idea of first and second order
self-awareness; both categories of self-awareness are considered as necessary
conditions for consciousness in terms of higher cognitive functions. We then
introduce a representation of first and second order self-awareness through
sets, and assume that these sets, which we call events, originally form a
collection of wellfounded sets. Strong virtual reality characterizes virtual
reality environments which have the limited capacity to create only events
associated with wellfounded sets. In contrast, the more general concept of weak
virtual reality characterizes collections of virtual reality mediated events
altogether forming an entirety larger than any collection of wellfounded sets.
By giving reference to Aczel's hyperset theory we indicate that this definition
is not empty, because hypersets encompass wellfounded sets already. Moreover,
we argue that weak virtual reality could be realized in human history through
continued progress in computer technology. Finally, we reformulate our
characterization into a more general framework, and use Baltag's Structural
Theory of Sets (STS) to show that within this general hyperset theory
Sommerhoff's first and second order self-awareness as well as both concepts of
virtual reality admit a consistent mathematical representation.Comment: 17 pages; several edits in v
Formal verification of coupling properties for an automotive software integration across XilL
Virtualization and desktop testing of an integrated system without inclusion
of a physical hardware is a well-established concept due to today’s abundant computing power
availability. However, only few aspects of reality are introduced in steps into these virtual
environments. The aspects of reality like hard-real time deadlines, timing events, coupling
frequency and data synchronization between two subsystems in a system offer complexity
without fair estimation of its consequence on the system behavior. In this paper, we
describe the abovementioned complexity as the coupling properties detailed for a combustion engine
example along with its controller. We formally verify the timing, safety, liveness and deadlock
properties of the coupling by modeling them as timed transition systems. The example is
verified for the idle speed control, smooth mode switching and for injection cutoff control where
the interaction between the subsystems is very critical. The paper highlights a very important
perspective of strong and weak subsystem coupling while transiting from Model-in-the-loop (MiL) to
Software-in-the-Loop (SiL) and finally to Hardware-in-the-Loop (HiL). In conclusion, the
input-output behavior of the coupled
subsystems is also presented for a realistic observation of the control loop
Asymptotic Freedom: From Paradox to Paradigm
Asymptotic freedom was developed as a response to two paradoxes: the
weirdness of quarks, and in particular their failure to radiate copiously when
struck; and the coexistence of special relativity and quantum theory, despite
the apparent singularity of quantum field theory. It resolved these paradoxes,
and catalyzed the development of several modern paradigms: the hard reality of
quarks and gluons, the origin of mass from energy, the simplicity of the early
universe, and the power of symmetry as a guide to physical law.Comment: 26 pages, 10 figures. Lecture on receipt of the 2004 Nobel Prize. v2:
typo (in Ohm's law) correcte
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Use of creative tools, technologies, processes and practices in the sectors of Art, Media, and Architecture: State-of the-Art and desired future scenarios
The aim of the paper is to analyse and present the preliminary findings of the EU FP7 funded CRe-AM project for the Art, Media, and Architecture sectors. This project bridges communities of technology providers and innovators with the creative industries, with the aim to build sector-specific dynamic roadmaps for the future of the European creative industries by examining the current state-of-the-art tools, technologies, processes, and practices supporting the creative process against the future scenarios envisioned by stakeholders in these sectors.This work was carried out as part of CRe-AM project, which is supported by European Commission (grant agreement n°612451)
Quantum Field Theory
I discuss the general principles underlying quantum field theory, and attempt
to identify its most profound consequences. The deepest of these consequences
result from the infinite number of degrees of freedom invoked to implement
locality. I mention a few of its most striking successes, both achieved and
prospective. Possible limitations of quantum field theory are viewed in the
light of its history.Comment: LaTeX, 12 pages, 3 figures. Will appear in Centenary issue of Rev. of
Mod. Phys., March 1999. Incorporated minor corrections suggested by edito
Fast Magnetic Reconnection and Spontaneous Stochasticity
Magnetic field-lines in astrophysical plasmas are expected to be frozen-in at
scales larger than the ion gyroradius. The rapid reconnection of magnetic flux
structures with dimensions vastly larger than the gyroradius requires a
breakdown in the standard Alfv\'en flux-freezing law. We attribute this
breakdown to ubiquitous MHD plasma turbulence with power-law scaling ranges of
velocity and magnetic energy spectra. Lagrangian particle trajectories in such
environments become "spontaneously stochastic", so that infinitely-many
magnetic field-lines are advected to each point and must be averaged to obtain
the resultant magnetic field. The relative distance between initial magnetic
field lines which arrive to the same final point depends upon the properties of
two-particle turbulent dispersion. We develop predictions based on the
phenomenological Goldreich & Sridhar theory of strong MHD turbulence and on
weak MHD turbulence theory. We recover the predictions of the Lazarian &
Vishniac theory for the reconnection rate of large-scale magnetic structures.
Lazarian & Vishniac also invoked "spontaneous stochasticity", but of the
field-lines rather than of the Lagrangian trajectories. More recent theories of
fast magnetic reconnection appeal to microscopic plasma processes that lead to
additional terms in the generalized Ohm's law, such as the collisionless Hall
term. We estimate quantitatively the effect of such processes on the
inertial-range turbulence dynamics and find them to be negligible in most
astrophysical environments. For example, the predictions of the
Lazarian-Vishniac theory are unchanged in Hall MHD turbulence with an extended
inertial range, whenever the ion skin depth is much smaller than the
turbulent integral length or injection-scale Comment: 31 pages, 5 figure
Using Frustration in the Design of Adaptive Videogames
In efforts to attract a wider audience, videogames are beginning to incorporate adaptive gameplay mechanics. Unlike the more traditional videogame, adaptive games can cater the gaming experience to the individual user and not just a particular group of users as with the former. Affective videogames, games that respond to the user's emotional state, may hold the key to creating such gameplay mechanics. In this paper we discus how the emotion frustration may be used in the design of adaptive videogames and the ongoing research into its detection and measurement
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