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2010 | Buch

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Coordination Models and Languages

12th International Conference, COORDINATION 2010, Amsterdam, The Netherlands, June 7-9, 2010. Proceedings

herausgegeben von: Dave Clarke, Gul Agha

Verlag: Springer Berlin Heidelberg

Buchreihe : Lecture Notes in Computer Science

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Inhaltsverzeichnis

Frontmatter

Observables for Mobile and Wireless Broadcasting Systems

Abstract

We discuss the presence of localities in observables for process calculi for mobile and wireless broadcasting systems in the context of weak barbed congruences and demonstrate that observability of the locality of a broadcasting node may be unsuitable when abstracting from node mobility, a natural abstraction current calculi agree upon. The discussion is carried out through a calculus bAπ, a conservative extension of the Applied π-calculus and a contribution of its own. Through examples we demonstrate the applicability of bAπ and its weak reduction congruence, where the locality of a broadcasting node is not observable, and we prove our bisimulation equivalence to be a sound and complete co-inductive characterization of the weak reduction congruence.

Jens Chr. Godskesen

Behavioural Contracts with Request-Response Operations

Abstract

In the context of service-oriented computing, behavioural contracts are abstract descriptions of the message-passing behaviour of services. They can be used to check properties of service compositions such as, for instance, client-service compliance. Previous formal models for contracts consider unidirectional send and receive operations. In this paper, we present two models for contracts with bidirectional request-response operations, in the presence of unboundedly many instances of both clients and servers. The first model takes inspiration from the abstract service interface language WSCL, the second one is inspired by Abstract WS-BPEL. We prove that client-service compliance is decidable in the former while it is undecidable in the latter, thus showing an interesting expressiveness gap between the modeling of request-response operations in WSCL and in Abstract WS-BPEL.

Lucia Acciai, Michele Boreale, Gianluigi Zavattaro

NOW: A Workflow Language for Orchestration in Nomadic Networks

Abstract

Existing workflow languages for nomadic or mobile ad hoc networks do not offer adequate support for dealing with the volatile connections inherent to these environments. Services residing on mobile devices are exposed to (temporary) network failures, which should be considered the rule rather than the exception. This paper proposes a nomadic workflow language built on top of an ambient-oriented programming language which supports dynamic service discovery and communication primitives resilient to network failures. Our proposed language provides high level workflow abstractions for control flow and supports rich network and service failure detection and handling through compensating actions. Moreover, we introduce a powerful variable binding mechanism which enables dynamic data flow between services in a nomadic environment. By adding this extra layer of abstraction on top of an ambient-oriented programming language, the application programmer is offered a flexible way to develop applications for nomadic networks.

Eline Philips, Ragnhild Van Der Straeten, Viviane Jonckers

A Calculus for Boxes and Traits in a Java-Like Setting

Abstract

The box model is a component model for the object-oriented paradigm, that defines components (the boxes) with clear encapsulation boundaries. Having well-defined boundaries is crucial in component-based software development, because it enables to argue about the interference and interaction between a component and its context. In general, boxes contain several objects and inner boxes, of which some are local to the box and cannot be accessed from other boxes and some can be accessible by other boxes. A trait is a set of methods divorced from any class hierarchy. Traits can be composed together to form classes or other traits. We present a calculus for boxes and traits. Traits are units of fine-grained reuse, whereas boxes can be seen as units of coarse-grained reuse. The calculus is equipped with an ownership type system and allows us to combine coarse- and fine-grained reuse of code by maintaining encapsulation of components.

Lorenzo Bettini, Ferruccio Damiani, Marco De Luca, Kathrin Geilmann, Jan Schäfer

JErlang: Erlang with Joins

Abstract

Erlang is an industrially successful functional language that uses the Actor model for concurrency. It supports the message-passing paradigm by providing pattern-matching over received messages. Unfortunately coding synchronisation between multiple processes is not straightforward. To overcome this limitation we designed and implemented JErlang, a Join-Calculus inspired extension to Erlang. We provide a rich set of language features with our joins. We present implementation details of our two alternative solutions, a library and an altered VM. Our optimisations provide JErlang with good performance.

Hubert Plociniczak, Susan Eisenbach

A Hybrid Visual Dataflow Language for Coordination in Mobile Ad Hoc Networks

Abstract

Because of the dynamic nature of mobile ad hoc networks and the applications running on top of them, these applications have to be conceived as event-driven architectures. Such architectures are hard to program because coordination between concurrent and distributed mobile components has to be expressed by means of event handlers or callbacks. Applications consisting of disjoint event handlers that are independently triggered (possibly by their environment) exhibit a very implicit control flow that is hard to grasp. This paper presents a visual dataflow language tailored towards mobile applications to express the interaction between mobile components that operate on data streams. By using a visual dataflow language as a separate coordination language, the coarse grained control flow of a mobile application can be specified visually and separately from the fine grained control flow. In its turn, this allows a very explicit view on the control flow of the entire mobile application.

Andoni Lombide Carreton, Theo D’Hondt

Compositional Construction of Real-Time Dataflow Networks

Abstract

Increasing sizes of present-day distributed software systems call for coordination models which are both modular and scalable. Precise modelling of real-life applications further requires the notion of real-time.

In this paper, we present a modular formal development of a compositional model for real-time coordination in dataflow networks. While real-time dataflow networks are typically asynchronous, our approach includes coordination patterns which combine, but are not limited to, synchrony and asynchrony. We define a constraint- and SAT-based encoding, which allows us to benefit from high-end constraint solving techniques when inspecting valid interactions of the system.

Stephanie Kemper

Coordinating Resource Usage through Adaptive Service Provisioning in Wireless Sensor Networks

Abstract

Wireless sensor networks (WSNs) exhibit high levels of network dynamics and consist of devices with limited energy. This results in the need to coordinate applications not only at the functional level, as is traditionally done, but also in terms of resource utilization. In this paper, we present a middleware that does this using adaptive service provisioning. Novel service binding strategies automatically adapt application behavior when opportunities for energy savings surface, and switch providers when the network topology changes. The former is accomplished by providing limited information about the energy consumption associated with using various services, systematically exploiting opportunities for sharing service invocations, and exploiting the broadcast nature of wireless communication in WSNs. The middleware has been implemented and evaluated on two disparate WSN platforms, the TelosB and Imote2. Empirical results show that adaptive service provisioning can enable energy-aware service binding decisions that result in increased energy efficiency and significantly increase service availability, while imposing minimal additional burden on the application, service, and device developers. Two applications, medical patient monitoring and structural health monitoring, demonstrate the middleware’s efficacy.

Chien-Liang Fok, Gruia-Catalin Roman, Chenyang Lu

Simulation and Analysis of Distributed Systems in Klaim

Abstract

Network and distributed systems typically consists of a large number of actors that act and interact with each other in a highly dynamic environment. Due to the number of involved actors and their strong dependence on mobility and interaction, performance and dependability issues are of utmost importance for this class of systems. StoKlaim is a stochastic extension of Klaim specifically thought to facilitate the incorporation of random phenomena in models for network-aware computing. In this paper we show how StoKlaim can be used to specify and verify quantitative properties of distributed systems. To support the analysis an automatic tool is introduced and used.

Francesco Calzolai, Michele Loreti

Modelling Railway Interlocking Tables Using Coloured Petri Nets

Abstract

Interlocking tables are the functional specification defining the routes, on which the passage of the train is allowed. Associated with the route, the states and actions of all related signalling equipment are also specified. This paper formally models the interlocking tables using Coloured Petri Nets (CPN). The CPN model comprises two parts: Signaling Layout and Interlocking Control. The Signaling Layout part is used to simulate the passage of the train. It stores geographic information of the signalling layout in tokens. The Interlocking Control part models actions of the controller according to the functions specified in the interlocking tables. The arc inscriptions in the model represent the content of the interlocking tables. Following our modelling approach we can reuse the same CPN net structure to model any new or modified interlocking system regardless of its size. Experimental results are presented to provide increased confidence in the model correctness.

Somsak Vanit-Anunchai

Efficient Session Type Guided Distributed Interaction

Abstract

Recently, there has been much interest in multi-party session types (MPSTs) as a means of rigorously specifying protocols for interaction among multiple distributed participants. By capturing distributed interaction as series of typed interactions, MPSTs allow for the static verification of compliance of corresponding distributed object programs. We observe that explicit control flow information manifested by MPST opens intriguing avenues also for performance enhancements. In this paper, we present a session type assisted performance enhancement framework for distributed object interaction in Java. Experimental evaluation within our distributed runtime infrastructure illustrates the costs and benefits of our composable enhancement strategies.

K. C. Sivaramakrishnan, Karthik Nagaraj, Lukasz Ziarek, Patrick Eugster

Scalable Efficient Composite Event Detection

Abstract

Composite event detection (CED) is the task of identifying combinations of events which are meaningful with respect to program-defined patterns. Recent research in event-based programming has focused on language design (in different paradigms), leading to a wealth of prototype programming models and languages. However, implementing CED in an efficient and scalable manner remains an under-addressed problem. In fact, the lack of scalable algorithms is the main roadblock to incorporating support for more expressive event patterns into prominent event-based programming languages. This lack of scalable algorithms is a particularly acute problem in event stream processing, where event patterns can additionally be specified over time windows. In this paper we describe GenTrie, a deterministic trie-based algorithm for CED. We describe how complex event patterns are split, how each sub-pattern maps to a node in the trie, and demonstrate through empirical evaluation that GenTrie has higher throughput than current implementations of related languages.

K. R. Jayaram, Patrick Eugster

Backmatter

Titel: Coordination Models and Languages
herausgegeben von: Dave Clarke
Gul Agha
Verlag: Springer Berlin Heidelberg
Electronic ISBN: 978-3-642-13414-2
Print ISBN: 978-3-642-13413-5
DOI: https://doi.org/10.1007/978-3-642-13414-2

Springer Professional

Inhaltsverzeichnis

Frontmatter

Observables for Mobile and Wireless Broadcasting Systems

Behavioural Contracts with Request-Response Operations

NOW: A Workflow Language for Orchestration in Nomadic Networks

A Calculus for Boxes and Traits in a Java-Like Setting

JErlang: Erlang with Joins

A Hybrid Visual Dataflow Language for Coordination in Mobile Ad Hoc Networks

Compositional Construction of Real-Time Dataflow Networks

Coordinating Resource Usage through Adaptive Service Provisioning in Wireless Sensor Networks

Simulation and Analysis of Distributed Systems in Klaim

Modelling Railway Interlocking Tables Using Coloured Petri Nets

Efficient Session Type Guided Distributed Interaction

Scalable Efficient Composite Event Detection

Backmatter

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