Partially distributed coordination with Reo and constraint automata

Algorithms and the Foundations of Software technolog

A Reo model of Software Defined Networks

Reo is a compositional coordination language for component connectors with a formal semantics based on automata. In this paper, we propose a formal model of software defined networks (SDNs) based on Reo where declarative constructs comprising of basic Reo primitives compose to specify descriptive models of both data and control planes of SDNs. We first describe the model of an SDN switch which can be compactly represented as a single state constraint automaton with a memory storing its flow table. A full network can then be compositionally constructed by composing the switches with basic communication channels. The reactive and proactive behaviour of the controllers in the control plane of an SDN can also be modelled by Reo connectors, which can compose the connectors representing data plane. The resulting model is suitable for testing, simulation, visualization, verification, and ultimately compilation into SDN switch code using the standard tools already available for Reo

Algebraic service composition for user-centric IoT applications

The Internet of Things (IoT) requires a shift in our way of building applications, as it is aimed at providing many services to society in general. Non-developer people require increasingly complex IoT applications and support for their ever changing run-time requirements. Although service composition allows the combination of functionality into more complex behaviours, current approaches provide support for dealing with one IoT scenario at a time, as they allow the definition of only one workflow. In this paper, we present DX-MAN, an algebraic model for static service composition that allows the definition of composite services that encompass multiple workflows for run-time scenarios. We evaluate our proposal on an example in the domain of smart homes

The genomic landscape of balanced cytogenetic abnormalities associated with human congenital anomalies

Despite the clinical significance of balanced chromosomal abnormalities (BCAs), their characterization has largely been restricted to cytogenetic resolution. We explored the landscape of BCAs at nucleotide resolution in 273 subjects with a spectrum of congenital anomalies. Whole-genome sequencing revised 93% of karyotypes and demonstrated complexity that was cryptic to karyotyping in 21% of BCAs, highlighting the limitations of conventional cytogenetic approaches. At least 33.9% of BCAs resulted in gene disruption that likely contributed to the developmental phenotype, 5.2% were associated with pathogenic genomic imbalances, and 7.3% disrupted topologically associated domains (TADs) encompassing known syndromic loci. Remarkably, BCA breakpoints in eight subjects altered a single TAD encompassing MEF2C, a known driver of 5q14.3 microdeletion syndrome, resulting in decreased MEF2C expression. We propose that sequence-level resolution dramatically improves prediction of clinical outcomes for balanced rearrangements and provides insight into new pathogenic mechanisms, such as altered regulation due to changes in chromosome topology

Data Dryad

Microsatellite data (10 loci) from Glionnetia sericea adults, seedlings and seeds

Branching pomsets:Design, expressiveness and applications to choreographies

Choreographic languages describe possible sequences of interactions among a set of agents. Typical models are based on languages or automata over sending and receiving actions. Pomsets provide a more compact alternative by using a partial order to explicitly represent causality and concurrency between these actions. However, pomsets offer no representation of choices, thus a set of pomsets is required to represent branching behaviour. For example, if an agent Alice can send one of two possible messages to Bob three times, one would need a set of 2 x 2 x 2 distinct pomsets to represent all possible branches of Alice's behaviour. This paper proposes an extension of pomsets, named branching pomsets, with a branching structure that can represent Alice's behaviour using 2 + 2 + 2 ordered actions. We compare the expressiveness of branching pomsets with that of several forms of event structures from the literature. We encode choreographies as branching pomsets and show that the pomset semantics of the encoded choreographies are bisimilar to their operational semantics. Furthermore, we define well-formedness conditions on branching pomsets, inspired by multiparty session types, and we prove that the well-formedness of a branching pomset is a sufficient condition for the realisability of the represented communication protocol. Finally, we present a prototype tool that implements our theory of branching pomsets, focusing on its applications to choreographies.</div

Agreeing on role adoption in open organisations

The organisational specification of a multi-agent system supports agents’ effectiveness in attaining their purpose, or prevent certain undesired behaviour from occurring. This requires that agents are able to find out about the organisational purpose and description and decide on its appropriateness for their own objectives. Organisational modeling languages are used to specify an agent system in terms of its roles, organizational structure, norms, etc. Agents take part in organisations by playing one or more of the specified roles for which they have the necessary capabilities. In this paper, we investigate the process of role adoption in the context of the well-known OperA organisational modelling language. In OperA, each organisation has a gatekeeper role responsible for admitting agents to the organisation. Agents playing the role of gatekeeper can interact with agents that want to enter the organisation in order to come to agreement on role adoption. That is, negotiate which roles they will play and under which conditions they will play them. This is possible by evaluating capability requirements for roles. We extend OperA to allow for the specification of role capabilities. This approach will be illustrated using the Blocks World for Teams (BW4T) domain.Infrastructures, Systems and ServicesTechnology, Policy and Managemen