Abstract. This paper presents Synapse, a scalable protocol for information retrieval over the inter-connection of heterogeneous overlay networks. Applications on top of Synapse see those intra-overlay networks as a unique inter-overlay network. Scalability in Synapse is achieved via co-located nodes, i.e. nodes that are part of multiple overlay networks at the same time. Co-located nodes, playing the role of neural synapses and connected to several overlay networks, allow a larger search area and provide alternative routing. Synapse can either work with "open" overlays adapting their protocol to synapse interconnection requirements, or with "closed" overlays that will not accept any change to their protocol. Results from simulation and experiments show that Synapse is scalable, with a communication and state overhead scaling similarly as the networks interconnected. Thanks to alternate routing paths, Synapse also gives a practical solution to network partitions. We precisely capture the behavior of traditional metrics of overlay networks within Synapse and present results from simulations as well as some actual experiments of a client prototype on the Grid'5000 platform. The prototype developed implements the Synapse protocol in the particular case of the interconnection of many Chord overlay networks.
Nowadays, executions of composite Web services are typically conducted by heavyweight centralized workflow engines. This represents a potential processing and communication bottleneck as well as a single point of failure. In addition to this, centralization induces higher deployment costs, such as a computing infrastructure to support the workflow engine, which is not affordable for a large number of small businesses and end-users. Last but not least, a central workflow engine might expose some security risks such as the business process discovery. More decentralized and dynamic interaction schemes are thus required.In this paper, we propose a decentralized alternative system for the execution of composite Web services based on an unconventional programming paradigm that relies on the chemical metaphor. It provides a high-level execution model that allows executing composite services in a fully decentralized manner. Our architecture is composed of nodes communicating through a persistent and fault-tolerant shared space containing both control and data flows, allowing to distribute the composition among nodes without the need for any centralized coordination.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.