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Since wireless sensor network applications are ever growing in scale and complexity, managers require strong formal guarantees that any changes done to the system can be enacted safely. This paper presents the formalisation and analysis of the semantics of policies, tiny software artefacts used to orchestrate wireless sensor network applications. The(More)
—In software product line (SPL) engineering, formal modelling and verification are critical for managing the inherent complexity of systems with a high degree of variability. The number of products in an SPL can be exponential in the number of features. Therefore, the challenge when modelling SPL lies in analysing and verifying large, complex models(More)
Reo Connector colouring a b s t r a c t Coordination in Reo emerges from the composition of the behavioural constraints of primitives, such as channels, in a component connector. Understanding and implementing Reo, however, has been challenging due to the interaction of the channel metaphor, which is an inherently local notion, and the non-local nature of(More)
Synchronous coordination systems, such as <i>Reo</i>, exchange data via indivisible actions, while distributed systems are typically asynchronous and assume that messages can be delayed or get lost. To combine these seemingly contradictory notions, we introduce the Dreams framework. Coordination patterns in Dreams are described using a synchronous model(More)
Modern software systems must support a high degree of variability to accommodate a wide range of requirements and operating conditions. This paper introduces the Abstract Behavioural Specification (ABS) language and tool suite, a comprehensive platform for developing and analysing highly adaptable distributed concurrent software systems. The ABS language(More)
Synchronous coordination systems allow the exchange of data by logically indivisible actions involving all coordinated entities. This paper introduces behavioural automata, a logically synchronous coordination model based on the Reo coordination language, which focuses on relevant aspects for the concurrent evolution of these systems. We show how our(More)
Reo is a language for coordinating autonomous components in distributed environments. Coordination in Reo is performed by circuit-like connectors, which are constructed from primitive, mobile channels with well-defined behaviour. While the structure of a connector can be modeled as a graph, its behaviour is com-positionally defined using that of its(More)
The primary objective of this study is to assess whether systematic differences in inefficiency are associated with hospital membership in different types of systems. We employed the Battese/Coelli simultaneous stochastic frontier analysis (SFA) technique to estimate hospital cost inefficiency. Mean estimated inefficiency was 8.42%. Membership in different(More)
Orc and Reo are two complementary approaches to the problem of coordinating components or services. On one hand, Orc is highly asynchronous, naturally dynamic, and based on ephemeral connections to services. On the other hand, Reo is based on the interplay between synchronization and mutual exclusion, is more static, and establishes more continuous(More)