NOW: A Workflow Language for Orchestration in Nomadic Networks

Philips, Eline; Straeten, Ragnhild Van Der; Jonckers, Viviane

doi:10.1007/978-3-642-13414-2_3

Cited by 4 publications

(5 citation statements)

References 16 publications

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“…Broker-based designs employ a single coordinator that centrally binds and invokes services [8], [9]. A broker synchronises parallel service flows naturally without additional effort because it executes the composition logic locally.…”

Section: Related Workmentioning

confidence: 99%

Synchronising Service Compositions in Dynamic Ad Hoc Environments

Groba

Clarke

2012

2012 IEEE First International Conference on Mobile Services

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Abstract-Service compositions in dynamic ad hoc environments face frequent changes in the network and service topology. Late service binding is a way to adapt to runtime changes but requires additional communication over error-prone and energy-constrained networks. In particular, synchronising parallel service flows relies on steady message exchange when mutually unknown service providers have to agree on a common merge node. Binding the merge node early through a single entity reduces the need for coordination. However, it compromises flexibility and may nonetheless increase communication as the decision entity has only partial view of the system. This paper proposes a multi-party late binding protocol as a solution for flexible, communication-aware service composition in dynamic ad hoc environments. The protocol integrates the discovery of unknown synchronisation partners with the exchange of binding suggestions to reduce communication. We embed this protocol in our model for opportunistic service composition and evaluate it against an early binding approach. Simulation results show that while being overall equally successful, late service binding outperforms early binding with respect to communication overhead and response time.

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Section: Related Workmentioning

confidence: 99%

Synchronising Service Compositions in Dynamic Ad Hoc Environments

Groba

Clarke

2012

2012 IEEE First International Conference on Mobile Services

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“…The group join pattern allows managing how control flow and data flow are merged. The default merging strategy used to merge the data environments of all instances is "accumulating all values for each variable", one of the merging strategies proposed in [5]. However, it is often wanted to specify another merging strategy.…”

Section: Fig 4 Synchronisation: the Barrier Patternmentioning

confidence: 99%

“…NOW [5] is a workflow language sculpted for nomadic networks [1]. These networks consist of a fixed infrastructure and mobile devices that try to maintain a connection with that infrastructure.…”

Section: Small Introduction To Nowmentioning

confidence: 99%

“…In case of fork patterns (like parallel split), this data environment is conceptually copied and when a join occurs (like a synchronization pattern), these incoming data environments are merged using a merging strategy (like choosing the one with a maximum value for a certain variable). For more detailed information we refer the interested reader to [5] and [6].…”

Section: Small Introduction To Nowmentioning

confidence: 99%

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Group Orchestration in a Mobile Environment

Philips

Vallejos

Straeten

et al. 2012

Lecture Notes in Computer Science

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Abstract. The increasing popularity of mobile devices fosters the omnipresence of services in mobile environments. Software systems in a mobile environment often want to manage a set of services that form a logical group and orchestrate the execution of a particular process for all its members. To orchestrate a group of services, abstractions are required which allow control over the execution in a way that transcends the individual process of a single member. Currently, existing languages do not offer adequate abstractions to perform said group orchestration in a reliable way. In this paper we present high-level abstractions for group orchestration as a new set of workflow patterns. We show how these patterns are integrated in an existing workflow language for nomadic networks, i.e. NOW. The workflow language NOW handles network and service failures at the core of the language. By extending this fault tolerance to the new group abstractions, we show how to conduct these in a reliable way.

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“…Centralised solutions employ a single coordinator that may be fixed or dynamically elected to allocate and invoke required services. A fixed coordinator [4] can cause long expensive routes, if it is not in vicinity of the mobile service providers. A dynamically appointed coordinator or broker [2] is more flexible because it is assigned afresh for each new request and selected based on how well it connects to required services.…”

Section: Progress Beyond the State-of-the-artmentioning

confidence: 99%

Towards Opportunistic Service Composition in Dynamic Ad Hoc Environments

Groba

2012

Service-Oriented Computing

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Service composition in pervasive computing envisions the collaboration of services provided by mobile and embedded devices to achieve complex application requirements. Although some research has investigated the composition of services in dynamic ad hoc settings, it is not clear how service composites manage the conflict between application layer complexities and network unreliability that may cause them to fail repeatedly. This paper outlines investigations on opportunistic service composition as a solution for managing complex service requests in mobile infrastructure-less environments. Opportunistic service composition dynamically transfers control among service providers to bind and execute services in a decentralised way. Unlike existing fragmentation and broker-based designs, it interleaves provider allocation with service execution to counteract mobility in a flexible manner. Early simulation results suggest that this approach reduces the failure probability and communication overhead of complex service requests. This illustrates that opportunistic service composition may be feasible to manage collaboration in dynamic ad hoc environments.Partially supported by Science Foundation Ireland grant 03/CE2/I303 1 to Lerothe Irish Software Engineering Research Centre (http://www.lero.ie).

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NOW: A Workflow Language for Orchestration in Nomadic Networks

Cited by 4 publications

References 16 publications

Synchronising Service Compositions in Dynamic Ad Hoc Environments

Synchronising Service Compositions in Dynamic Ad Hoc Environments

Group Orchestration in a Mobile Environment

Towards Opportunistic Service Composition in Dynamic Ad Hoc Environments

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