Fundamenta Informaticae - Volume 73, issue 4

Authors: Brogi, Antonio | Jacquet, Jean-Marie | Kok, Joost

Article Type: Other

Citation: Fundamenta Informaticae, vol. 73, no. 4, pp. i-ii, 2006

Authors: Brogi, Antonio | Jacquet, Jean-Marie | Linden, Isabelle

Article Type: Research Article

Abstract: The paper proposes a theoretical study of a coordination language embodying Linda's asynchronous communication primitives with a refined matching mechanism based on pairs composed of attribute names associated with their values. Computations in this language are described by means of an operational semantics, reporting the whole traces of executions. The non-compositionality of this intuitive operational semantics motivates the design of a compositional and fully abstract denotational semantics.

Keywords: Coordination language, semantics

Citation: Fundamenta Informaticae, vol. 73, no. 4, pp. 431-478, 2006

Authors: Gorrieri,, Roberto | Lucchi, Roberto | Zavattaro, Gianluigi

Article Type: Research Article

Abstract: In this paper we investigate security problems which occur when exploiting a Linda-like data driven coordination model in an open environment. In this scenario, there is no guarantee that all the agents accessing the shared tuple space are trusted. Starting from a formalization of some typical security properties in the standard Linda coordination model, we present a novel data-driven coordination model which provides mechanisms to support the considered security properties. The first of these mechanisms supports …logical partitions of the shared repository: in this way we can restrict the access to tuples stored inside a partition, simply by limiting the access to the partition itself. The second mechanism consists of adding to the tuples some extra information which permits to authenticate the producer of a tuple or to identify its reader/consumer. Finally, we support the possibility to define access control policies based on the kind of operations an agent performs on a tuple, thus discriminating between (destructive) input and (non-destructive) read permissions on each single tuple. Show more

Citation: Fundamenta Informaticae, vol. 73, no. 4, pp. 479-506, 2006

Authors: Viroli, Mirko | Omicini, Andrea

Article Type: Research Article

Abstract: Coordination models like LINDA were first conceived in the context of closed systems, like high-performance parallel applications. There, all coordinated entities were known once and for all at design time, and coordination media were conceptually part of the coordinated application. Correspondingly, traditional formalisations of coordination models – where both coordinated entities and coordination media are uniformly represented as terms of a process algebra – endorse the viewpoint of coordination as a language for …building concurrent systems. The complexity of today application scenarios calls for a new approach to the formalisation of coordination models. Open systems, typically hosting a multiplicity of applications working concurrently, require coordination to be imposed through powerful abstractions that (i) persist through the whole engineering process – from design to execution time – and (ii) provide coordination services to applications by a shared infrastructure in the form of coordination media. As a unifying framework for a number of existing works on the semantics of coordination media, in this paper we present a basic ontology and a formal framework endorsing the viewpoint of coordination as a service. By this framework, coordination media are characterised in terms of their interactive behaviour, and are seen as primary abstractions amenable of formal investigation, promoting their exploitation at every step of the engineering process. Show more

Citation: Fundamenta Informaticae, vol. 73, no. 4, pp. 507-534, 2006

Authors: Orzan, Simona | van de Pol, Jaco

Article Type: Research Article

Abstract: We study a simple software architecture, in which components are coordinated by writing into and reading from a global set. This simple architecture is inspired by the industrial software architecture Splice. We present two results. First, a distributed implementation of the architecture is given and proved correct formally. In the implementation, local sets are maintained and data items are exchanged between these local sets. Next we show that the architecture is sufficiently expressive in principle. In …particular, every global specification of a system's behaviour can be divided into components, which coordinate by read and write primitives on a global set only. We heavily rely on recent concepts and proof methods from process algebra. Show more

Citation: Fundamenta Informaticae, vol. 73, no. 4, pp. 535-559, 2006

Authors: Guillen-Scholten, Juan | Arbab, Farhad | de Boer, Frank | Bonsangue, Marcello

Article Type: Research Article

Abstract: In this paper we present a coordination model for component-based software systems based on the notion of mobile channels, define it in terms of a compositional trace-based semantics, and describe its implementation in the Java language. Channels allow anonymous, and point-to-point communication among components, while mobility allows dynamic reconfiguration of channel connections in a system. This model supports dynamic distributed systems where components can be mobile. It provides an efficient way of interaction among …components. Furthermore, our model provides a clear separation between the computational part and the coordination part of a system, allowing the development and description of the coordination structure of a system to be done in a transparent and exogenous manner. Our description of the Java implementation of this coordination model demonstrates that it is self-contained enough for developing component-based systems in object-oriented languages. However, if desired, our model can be used as a basis to extend other models that focus on other aspects of components that are less concerned with composition and coordination issues. Show more

Citation: Fundamenta Informaticae, vol. 73, no. 4, pp. 561-582, 2006

Authors: Vallecillo, Antonio | Vasconcelos, Vasco T. | Ravara, António

Article Type: Research Article

Abstract: This paper proposes the use of session types to extend with behavioural information the simple descriptions usually provided by software component interfaces. We show how session types allow not only high level specifications of complex interactions, but also the definition of powerful interoperability tests at the protocol level, namely compatibility and substitutability of components. We present a decidable proof system to verify these notions, which makes our approach of a pragmatic nature.

Citation: Fundamenta Informaticae, vol. 73, no. 4, pp. 583-598, 2006