6,367 research outputs found
Evaluating the performance of model transformation styles in Maude
Rule-based programming has been shown to be very successful in many application areas. Two prominent examples are the specification of model transformations in model driven development approaches and the definition of structured operational semantics of formal languages. General rewriting frameworks such as Maude are flexible enough to allow the programmer to adopt and mix various rule styles. The choice between styles can be biased by the programmer’s background. For instance, experts in visual formalisms might prefer graph-rewriting styles, while experts in semantics might prefer structurally inductive rules. This paper evaluates the performance of different rule styles on a significant benchmark taken from the literature on model transformation. Depending on the actual transformation being carried out, our results show that different rule styles can offer drastically different performances. We point out the situations from which each rule style benefits to offer a valuable set of hints for choosing one style over the other
Neurodegenerative diseases: complexity of clinical phenotypes in genetic models of alzheimer’s disease and frontotemporal dementia
Effect of Beam Dynamics Processes in the Low Energy Ring ThomX
As part of the R\&D for the 50 MeV ThomX Compton source project, we have
studied the effect of several beam dynamics processes on the evolution of the
beam in the ring. The processes studied include among others Compton
scattering, intrabeam scattering, coherent synchrotron radiation. We have
performed extensive simulations of a full injection/extraction cycle (400000
turns). We show how each of these processes degrades the flux of photons
produced and how a feedback system contributes to recovering most of the flux.Comment: Submitted to IPAC'14, WEPRO00
The Speciality Index as invariant indicator in the BKL Mixmaster Dynamics
The speciality index, which has been mainly used in Numerical Relativity for
studying gravitational waves phenomena as an indicator of the special or
non-special Petrov type character of a spacetime, is applied here in the
context of Mixmaster cosmology, using the Belinski-Khalatnikov-Lifshitz map.
Possible applications for the associated chaotic dynamics are discussed
Coordination of Dynamic Software Components with JavaBIP
JavaBIP allows the coordination of software components by clearly separating
the functional and coordination aspects of the system behavior. JavaBIP
implements the principles of the BIP component framework rooted in rigorous
operational semantics. Recent work both on BIP and JavaBIP allows the
coordination of static components defined prior to system deployment, i.e., the
architecture of the coordinated system is fixed in terms of its component
instances. Nevertheless, modern systems, often make use of components that can
register and deregister dynamically during system execution. In this paper, we
present an extension of JavaBIP that can handle this type of dynamicity. We use
first-order interaction logic to define synchronization constraints based on
component types. Additionally, we use directed graphs with edge coloring to
model dependencies among components that determine the validity of an online
system. We present the software architecture of our implementation, provide and
discuss performance evaluation results.Comment: Technical report that accompanies the paper accepted at the 14th
International Conference on Formal Aspects of Component Softwar
Electron Beam Dynamics in the 50 MeV ThomX Compact Storage Ring
International audienceThomX is a high flux compact X-ray source based on Compton back scattering between a relativistic electron beam and an intense laser pulse. To increase the repetition rate, the electron beam is stored in a ring. The main drawback of such a scheme is the low energy of the electrons regarding collective effects and intrabeam scattering. These effects tend to enlarge or even disrupt the stored bunch and they limit its charge, especially in a system where damping plays a negligible role. Thus such collective effects reduce the maximum X-ray flux and it is important to investigate them to predict the performance of this type of X-ray source. In addition, the Compton back scattering acts on the electron beam by increasing its energy spread. This presentation will show firstly the impact of collective effects on the electron beam, essentially during the first turns when they are the most harmful. Then, the reduction of the X-ray flux due to Compton back scattering and intrabeam scattering will be investigated on a longer time scale
Multidimensional evaluation in clinical diagnosis of Alzheimer’s disease: genetic risk in Alzheimer’s disease and neurodegenerative dementias
On the Asymptotic Stability of De-Sitter Spacetime: a non-linear perturbative approach
We derive evolution and constraint equations for second order perturbations
of flat dust homogeneous and isotropic solutions to the Einstein field
equations using all scalar, vector and tensor perturbation modes. We show that
the perturbations decay asymptotically in time and that the solutions converge
to the De-Sitter solution. By induction, this result is valid for perturbations
of arbitrary order. This is in agreement with the cosmic no-hair conjecture of
Gibbons and Hawking.Comment: 11 pages, 2 figure
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