33,723 research outputs found
Serious Games in Cultural Heritage
Although the widespread use of gaming for leisure purposes has been well documented, the use of games to support cultural heritage purposes, such as historical teaching and learning, or for enhancing museum visits, has been less well considered. The state-of-the-art in serious game technology is identical to that of the state-of-the-art in entertainment games technology. As a result the field of serious heritage games concerns itself with recent advances in computer games, real-time computer graphics, virtual and augmented reality and artificial intelligence. On the other hand, the main strengths of serious gaming applications may be generalised as being in the areas of communication, visual expression of information, collaboration mechanisms, interactivity and entertainment. In this report, we will focus on the state-of-the-art with respect to the theories, methods and technologies used in serious heritage games. We provide an overview of existing literature of relevance to the domain, discuss the strengths and weaknesses of the described methods and point out unsolved problems and challenges. In addition, several case studies illustrating the application of methods and technologies used in cultural heritage are presented
Recurrent shell infall events in a B0.5e star: HD 58978 1979-1988
Infall from the circumstellar envelope onto the bright B0.5 IVe star, HD 58978 was studied. The IUE data indicate that the star was surrounded by a low and moderately ionized circumstellar shell at least 12 times between 1979 and 1988. During 6 of these episodes, the signatures of cool circumstellar material were redshifted with respect to the photosphere by 20 to 80 km/sec. The data indicate that the transition from infall to minimal shell absorption can occur in under 10 days, and are consistent either with infall phases lasting up to 6 months, or with infall episodes shorter than 10 to 15 days. The long term behavior of the shell episodes is compared with variability in the stellar wind
Study of Beam Losses at Injection in the CERN Proton Synchrotron
The maximum intensity the CERN PS has to deliver is continuously increasing. In particular, during the next years, one of the most intense beams ever produced in the PS, with up to 3000 1010 proton per pulse, should be delivered on a regular basis for the CNGS physics program. It is now known that the existing radiation shielding of the PS in some places is too weak and constitutes a major limitation due to large beam losses in specific locations of the machine. This is the case for the injection region: losses appear on the injection septum when the beam is injected in the ring and during the first turn, due to an optical mismatch between the injection line and the PS. This paper presents the experimental studies and the simulations which have been made to understand the loss pattern in the injection region. Possible solutions to reduce the beam losses will be described, including the computation of a new injection optics
Constructing Real-Time Systems from Temporal I/O Automata
A new class of communicating automata called Temporal Input/Output Automata (TAi/os) is introduced. A TAi/o is a predicate automaton used to specify real-time systems. The specification provided by a TAi/o includes state predicates with proof expressions and abstract program syntax as attributes. An abstract program is extracted during a constructive proof of the specification using the proof expressions. A TAi/o specification also includes hard, real-time constraints on program behavior. The predictability of deterministic, temporally complete TAi/o is investigated. The formulation of real-time system transductions and transduction rules for TAi/os in explicit clock temporal logic is given. An illustration of the use of TAi/os in specifying light-controlled vehicles is presented. To illustrate the methodology in constructive reasoning about a TAi/o, a proof which derives a partial abstract program is given
Explicit Clock Temporal Logic in Timing Constraints for Real-Time Systems
A form of explicit clock temporal logic (called TLrt) useful in specifying timing constraints on controller actions, a real-time database (rtdb) items, and constraints in a real-time constraint base (rtcb), is presented. Timing as well as other forms of constraints are stored in the rtcb. A knowledge-based approach to ensure the integrity of information in an rtdb is given. The rtcb is realized as a logic program called Constrainer, which is a historyless integrity checker for a real-time database. The consistency and integrity issues for an rtcb and rtdb are investigated. The formal bases for a temporally complete rtdb and knowledgeably complete controller are presented. A partial TLrt specification of a knowledgeable controller for a Gas Burner is given. An illustration of a rtdb and rtcb in the context of the sample real-time system is also given
Computing approximate stationary distributions for discrete Markov processes with banded infinitesimal generators
We develop an algorithm for computing approximations to the stationary distribution of a discrete birth-and-death process, provided that the infinitesimal generator is a banded matrix. We begin by computing stationary distributions for processes whose infinitesimal generators are Hessenberg. Our derivation in this special case is different from the classical case but it leads to the same result. We then show how to extend these ideas to processes where the infinitesimal generator is banded (or half-banded) and to quasi-birth-death processes. Finally, we give an example of the application of this method to a nearly completely decomposable Markov chain to demonstrate the general applicability of the technique
Dynamical aspects of inextensible chains
In the present work the dynamics of a continuous inextensible chain is
studied. The chain is regarded as a system of small particles subjected to
constraints on their reciprocal distances. It is proposed a treatment of
systems of this kind based on a set Langevin equations in which the noise is
characterized by a non-gaussian probability distribution. The method is
explained in the case of a freely hinged chain. In particular, the generating
functional of the correlation functions of the relevant degrees of freedom
which describe the conformations of this chain is derived. It is shown that in
the continuous limit this generating functional coincides with a model of an
inextensible chain previously discussed by one of the authors of this work.
Next, the approach developed here is applied to a inextensible chain, called
the freely jointed bar chain, in which the basic units are small extended
objects. The generating functional of the freely jointed bar chain is
constructed. It is shown that it differs profoundly from that of the freely
hinged chain. Despite the differences, it is verified that in the continuous
limit both generating functionals coincide as it is expected.Comment: 15 pages, LaTeX 2e + various packages, 3 figures. The title has been
changed and three references have been added. A large part of the manuscript
has been rewritten to improve readability. Chapter 4 has been added. It
contains the construction of the generating functional without the
shish-kebab approximation and a new derivation of the continuous limit of the
freely jointed bar chai
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