150 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
Towards an Entropy-based Analysis of Log Variability
Rules, decisions, and workflows are intertwined components depicting the overall process. So far imperative workflow modelling languages have played the major role for the description and analysis of business processes. Despite their undoubted efficacy in representing sequential executions, they hide circumstantial information leading to the enactment of activities, and obscure the rationale behind the verification of requirements, dependencies, and goals. This workshop aimed at providing a platform for the discussion and introduction of new ideas related to the development of a holistic approach that encompasses all those aspects. The objective was to extend the reach of the business process management audience towards the decisions and rules community and increase the integration between different imperative, declarative and hybrid modelling perspectives. Out of the high-quality submitted manuscripts, three papers were accepted for publication, with an acceptance rate of 50%. They contributed to foster a fruitful discussion among the participants about the respective impact and the interplay of decision perspective and the process perspective
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
High resolution measurements of carbon monoxide along a late Holocene Greenland ice core: evidence for in situ production
We present high-resolution measurements of carbon monoxide (CO)
concentrations from a shallow ice core of the North Greenland Eemian Ice
Drilling project (NEEM-2011-S1). An optical-feedback cavity-enhanced
absorption spectrometer (OF-CEAS) coupled to a continuous melter system
performed continuous, online analysis during a four-week measurement campaign.
This analytical setup generated stable measurements of CO concentrations
with an external precision of 7.8 ppbv (1σ), based on repeated
analyses of equivalent ice core sections. However, this first application of
this measurement technique suffered from a poorly constrained procedural
blank of 48 ± 25 ppbv and poor accuracy because an absolute
calibration was not possible. The NEEM-2011-S1 CO record spans 1800 yr and
the long-term trends within the most recent section of this record
(i.e., post 1700 AD) resemble the existing discrete CO measurements from the
Eurocore ice core. However, the CO concentration is highly variable (75–1327 ppbv
range) throughout the ice core with high frequency (annual scale), high
amplitude spikes characterizing the record. These CO signals are too abrupt
and rapid to reflect atmospheric variability and their prevalence largely
prevents interpretation of the record in terms of atmospheric CO variation.
The abrupt CO spikes are likely the result of in situ production occurring
within the ice itself, although the unlikely possibility of CO production
driven by non-photolytic, fast kinetic processes within the continuous
melter system cannot be excluded. We observe that 68% of the CO spikes
are observed in ice layers enriched with pyrogenic aerosols. Such aerosols,
originating from boreal biomass burning emissions, contain organic
compounds, which may be oxidized or photodissociated to produce CO within
the ice. However, the NEEM-2011-S1 record displays an increase of
~0.05 ppbv yr<sup>−1</sup> in baseline CO level prior to 1700 AD (129 m
depth) and the concentration remains elevated, even for ice layers depleted
in dissolved organic carbon (DOC). Thus, the processes driving the likely
in situ production of CO within the NEEM ice may involve multiple, complex
chemical pathways not all related to past fire history and require further investigation
In Situ Analysis of Bacterial Lipopeptide Antibiotics by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging
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