On Dead Path Elimination in Decentralized Process Executions

There has been a great deal of interest in recent years in the use of service oriented approach and relevant standards to implement business processes. Following the concepts of workflow-based process management, the major focus has been on service composition. Not surprisingly, this default composition approach suffers from the limitations of centralized workflow management. It is well recognized that a decentralized execution setting where composed services can establish P2P interactions, is central to a wide range of ubiquitous, mobile, large-scale and secure business process management. A natural way to enable the decentralized execution is to implement the relevant distributed cooperating processes of a centralized process on composed services. In this way, composed services can establish P2P interactions following the semantics of their processes. In this report, we present a generic approach that enables decentralized executions with such cooperating processes. Precisely, we present our method that derives the latter. We focus on the sophisticated control/data flow, conversationional aspects and especially Dead Path Elimination that run counter to naive intuition, most of which, we explain using deeper analysis of the algorithms and data structures that we employed

CHOReOS perspective on the Future Internet and initial conceptual model (D1.2)

The D1.2 deliverable outlines the CHOReOS perspective on the Future Internet and its conceptualization. In particular, the deliverable focuses on: - Definition of the Future Internet and related Future Internet of Services and (Smart) Things, as considered within CHOReOS, further stressing the many dimensions underpinning the Ultra-Large Scale of the Future Internet; - Definition of the initial conceptual model of the CHOReOS Service-Oriented Architecture (SOA) for the Future Internet, identifying the impact of the ULS dimensions upon the traditional SOA paradigms and associated infrastructure

On the construction of decentralised service-oriented orchestration systems

Modern science relies on workflow technology to capture, process, and analyse data obtained from scientific instruments. Scientific workflows are precise descriptions of experiments in which multiple computational tasks are coordinated based on the dataflows between them. Orchestrating scientific workflows presents a significant research challenge: they are typically executed in a manner such that all data pass through a centralised computer server known as the engine, which causes unnecessary network traffic that leads to a performance bottleneck. These workflows are commonly composed of services that perform computation over geographically distributed resources, and involve the management of dataflows between them. Centralised orchestration is clearly not a scalable approach for coordinating services dispersed across distant geographical locations. This thesis presents a scalable decentralised service-oriented orchestration system that relies on a high-level data coordination language for the specification and execution of workflows. This system’s architecture consists of distributed engines, each of which is responsible for executing part of the overall workflow. It exploits parallelism in the workflow by decomposing it into smaller sub-workflows, and determines the most appropriate engines to execute them using computation placement analysis. This permits the workflow logic to be distributed closer to the services providing the data for execution, which reduces the overall data transfer in the workflow and improves its execution time. This thesis provides an evaluation of the presented system which concludes that decentralised orchestration provides scalability benefits over centralised orchestration, and improves the overall performance of executing a service-oriented workflow

Towards Decentralized Service Orchestrations

http://portal.acm.org/International audienceThere are several independent motivations for the implementation of decentralized execution settings for business processes that subject service compositions. This paper reports a new approach to truly decentralized orchestration of service compositions. Precisely, we provide an efficient process transformation technique that converts a process conceived for centralized execution to a set of nested processes to be deployed on dynamically bound services. Following the motivation that services are invokable with relevant processes, our proposition enables services to establish direct interconnections as analogous to P2P computing