445 research outputs found
Declarative Choreographies and Liveness
Part 1: Full PapersInternational audienceWe provide the first formal model for declarative choreographies, which is able to express general omega-regular liveness properties. We use the Dynamic Condition Response (DCR) graphs notation for both choreographies and end-points. We define end-point projection as a restriction of DCR graphs and derive the condition for end-point projectability from the causal relationships of the graph. We illustrate the results with a running example of a Buyer-Seller-Shipper protocol. All the examples are available for simulation in the online DCR workbench at http://dcr.tools/forte19
A Logic for Choreographies
We explore logical reasoning for the global calculus, a coordination model
based on the notion of choreography, with the aim to provide a methodology for
specification and verification of structured communications. Starting with an
extension of Hennessy-Milner logic, we present the global logic (GL), a modal
logic describing possible interactions among participants in a choreography. We
illustrate its use by giving examples of properties on service specifications.
Finally, we show that, despite GL is undecidable, there is a significant
decidable fragment which we provide with a sound and complete proof system for
checking validity of formulae.Comment: In Proceedings PLACES 2010, arXiv:1110.385
Bigraphical Refinement
We propose a mechanism for the vertical refinement of bigraphical reactive
systems, based upon a mechanism for limiting observations and utilising the
underlying categorical structure of bigraphs. We present a motivating example
to demonstrate that the proposed notion of refinement is sensible with respect
to the theory of bigraphical reactive systems; and we propose a sufficient
condition for guaranteeing the existence of a safety-preserving vertical
refinement. We postulate the existence of a complimentary notion of horizontal
refinement for bigraphical agents, and finally we discuss the connection of
this work to the general refinement of Reeves and Streader.Comment: In Proceedings Refine 2011, arXiv:1106.348
Dark Matter and Baryons in the Most X-ray Luminous and Merging Galaxy Cluster RX J1347.5-1145
The galaxy cluster RX J1347-1145 is one of the most X-ray luminous and most
massive clusters known. Its extreme mass makes it a prime target for studying
issues addressing cluster formation and cosmology. In this paper we present new
high-resolution HST/ACS and Chandra X-ray data. The high resolution and
sensitivity of ACS enabled us to detect and quantify several new multiply
imaged sources, we now use a total of eight for the strong lensing analysis.
Combining this information with shape measurements of weak lensing sources in
the central regions of the cluster, we derive a high-resolution,
absolutely-calibrated mass map. This map provides the best available
quantification of the total mass of the central part of the cluster to date. We
compare the reconstructed mass with that inferred from the new Chandra X-ray
data, and conclude that both mass estimates agree extremely well in the
observed region, namely within 400 / h_70 kpc of the cluster center. In
addition we study the major baryonic components (gas and stars) and hence
derive the dark matter distribution in the center of the cluster. We find that
the dark matter and baryons are both centered on the BCG within the
uncertainties (alignment is better than <10 kpc). We measure the corresponding
1-D profiles and find that dark matter distribution is consistent with both NFW
and cored profiles, indicating that a more extended radial analysis is needed
to pinpoint the concentration parameter, and hence the inner slope of the dark
matter profile.Comment: 12 pages, Accepted for publication in ApJ, full-res version
http://www.physics.ucsb.edu/~marusa/RXJ1347.pd
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