A Specification Language for the WIDE Workflow Model

This paper presents a workflow specification language developed in the WIDE project. The language provides a rich organisation model, an information model including presentation details, and a sophisticated process model. Workflow application developers should find the language a useful and compact means to capture and investigate design details. Workflow system developers would discover the language a good vehicle to study the interaction between different features as well as facilitate the development of more advanced features. Others would attain a better understanding of the workflow paradigm and could use the language ms a basis of evaluation for the functionality of workflow systems

CiAN: A Language and Middleware for Collaboration in Ad hoc Networks

Designing software that supports collaboration among multiple users in mobile ad hoc networks is challenging due to the dynamic network topology and inherent unpredictability of the environment. However, as we increasingly migrate to using mobile computing platforms, there is a pertinent need for software that can support a wide range of collaborative activities anywhere and at any time without relying on any external infrastructure. In this paper, we adopt the workflow model to represent the structure of an activity that involves multiple tasks being performed in a structured, collaborative fashion by multiple users. Using the workflow model as a base, we developed an XML based specification language called CiAN that can be used to build workflows that can be fragmented and distributed across the hosts of participating users so that the collaborative activity is executed in a distributed manner. The tasks specified in the CiAN language are executed by our Java based CiAN middleware, which runs on mobile hosts. Communication of task results between hosts occurs via a novel protocol that uses the workflow structure to make routing decisions on data packets. Complete implementation details and an evaluation of our approach are also presented

A Dataflow Language for Decentralised Orchestration of Web Service Workflows

Orchestrating centralised service-oriented workflows presents significant scalability challenges that include: the consumption of network bandwidth, degradation of performance, and single points of failure. This paper presents a high-level dataflow specification language that attempts to address these scalability challenges. This language provides simple abstractions for orchestrating large-scale web service workflows, and separates between the workflow logic and its execution. It is based on a data-driven model that permits parallelism to improve the workflow performance. We provide a decentralised architecture that allows the computation logic to be moved "closer" to services involved in the workflow. This is achieved through partitioning the workflow specification into smaller fragments that may be sent to remote orchestration services for execution. The orchestration services rely on proxies that exploit connectivity to services in the workflow. These proxies perform service invocations and compositions on behalf of the orchestration services, and carry out data collection, retrieval, and mediation tasks. The evaluation of our architecture implementation concludes that our decentralised approach reduces the execution time of workflows, and scales accordingly with the increasing size of data sets.Comment: To appear in Proceedings of the IEEE 2013 7th International Workshop on Scientific Workflows, in conjunction with IEEE SERVICES 201

E-BioFlow: Different Perspectives on Scientific Workflows

We introduce a new type of workflow design system called\ud e-BioFlow and illustrate it by means of a simple sequence alignment workflow. E-BioFlow, intended to model advanced scientific workflows, enables the user to model a workflow from three different but strongly coupled perspectives: the control flow perspective, the data flow perspective, and the resource perspective. All three perspectives are of\ud equal importance, but workflow designers from different domains prefer different perspectives as entry points for their design, and a single workflow designer may prefer different perspectives in different stages of workflow design. Each perspective provides its own type of information, visualisation and support for validation. Combining these three perspectives in a single application provides a new and flexible way of modelling workflows

A Constrained Object Model for Configuration Based Workflow Composition

Automatic or assisted workflow composition is a field of intense research for applications to the world wide web or to business process modeling. Workflow composition is traditionally addressed in various ways, generally via theorem proving techniques. Recent research observed that building a composite workflow bears strong relationships with finite model search, and that some workflow languages can be defined as constrained object metamodels . This lead to consider the viability of applying configuration techniques to this problem, which was proven feasible. Constrained based configuration expects a constrained object model as input. The purpose of this document is to formally specify the constrained object model involved in ongoing experiments and research using the Z specification language.Comment: This is an extended version of the article published at BPM'05, Third International Conference on Business Process Management, Nancy Franc

A Taxonomy of Workflow Management Systems for Grid Computing

With the advent of Grid and application technologies, scientists and engineers are building more and more complex applications to manage and process large data sets, and execute scientific experiments on distributed resources. Such application scenarios require means for composing and executing complex workflows. Therefore, many efforts have been made towards the development of workflow management systems for Grid computing. In this paper, we propose a taxonomy that characterizes and classifies various approaches for building and executing workflows on Grids. We also survey several representative Grid workflow systems developed by various projects world-wide to demonstrate the comprehensiveness of the taxonomy. The taxonomy not only highlights the design and engineering similarities and differences of state-of-the-art in Grid workflow systems, but also identifies the areas that need further research.Comment: 29 pages, 15 figure

WIDE - A Distributed Architecture for Workflow Management

This paper presents the distributed architecture of the WIDE workflow management system. We show how distribution and scalability are obtained by the use of a distributed object model, a client/server architecture, and a distributed workflow server architecture. Specific attention is paid to the extended transaction support and active rule support subarchitectures

Fluent Logic Workflow Analyser: A Tool for The Verification of Workflow Properties

In this paper we present the design and implementation, as well as a use case, of a tool for workflow analysis. The tool provides an assistant for the specification of properties of a workflow model. The specification language for property description is Fluent Linear Time Temporal Logic. Fluents provide an adequate flexibility for capturing properties of workflows. Both the model and the properties are encoded, in an automated way, as Labelled Transition Systems, and the analysis is reduced to model checking.Comment: In Proceedings LAFM 2013, arXiv:1401.056