Web Service Workflow Research Articles

Business process verification – finally a reality!

PurposeThe purpose of this paper is to demonstrate that process verification has matured to a level where it can be used in practice. This paper reports on new verification techniques that can be used to assess the correctness of real‐life models.Design/methodology/approachThe proposed approach relies on using formal methods to determine the correctness of business processes with cancellation and OR‐joins. The paper also demonstrates how reduction rules can be used to improve the efficiency. These techniques are presented in the context of the workflow language yet another workflow language (YAWL) that provides direct support for 20 most frequently used patterns found today (including cancellation and OR‐joins). But the results also apply to other languages with these features (e.g. BPMN, EPCs, UML activity diagrams, etc.). An editor has been developed that provides diagnostic information based on the techniques presented in this paper.FindingsThe paper proposes four properties for business processes with cancellation and OR‐joins, namely: soundness, weak soundness, irreducible cancellation regions and immutable OR‐joins and develop new techniques to verify these properties. Reduction rules have been used as a means of improving the efficiency of the algorithm. The paper demonstrates the feasibility of this verification approach using a realistic and complex business process, the visa application process for general skilled migration to Australia, modelled as a YAWL workflow with cancellation regions and OR‐joins.Originality/valueBusiness processes sometimes require complex execution interdependencies to properly complete a process. For instance, it is possible that certain activities need to be cancelled mid‐way though the process. Some parallel activities may require complex “wait and see” style synchronisation depending on a given context. These types of business processes can be found in various domains, such as application integration, B2B commerce, web service composition and workflow systems. Even though cancellation and sophisticated join structures are present in many business processes, existing verification techniques are unable to deal with such processes. Hence, this paper plays an important role in making process verification a reality.

SOFTWARE ENGINEERING FOR WEB SERVICES WORKFLOW SYSTEMS

Service-oriented computing (SOC) suggests that many open, network-accessible services will be available over the Internet for organizations to incorporate into their own processes. Developing new software systems by composing an organization's local services and externally-available web services is conceptually different from system development supported by traditional software engineering lifecycles. Consumer organizations typically have no control over the quality and/or consistency of the external services that they incorporate, thus top-down software development lifecycles are impractical. Software architects and designers will require agile, lightweight processes to evaluate tradeoffs in system design based on the "estimated" responsiveness of external services coupled with known performance of local services. We introduce a model-driven software engineering approach for designing systems (i.e. workflows of web services) under these circumstances and a corresponding simulation-based evaluation tool.

UCLPv2: a network virtualization framework built on web services [web services in telecommunications, part II

User controlled LightPaths version 2 provides a network virtualization framework upon which communities of users can build their own services or applications without dealing with the complexities of the underlying network technologies and still can maintain the functionality that the network provides. The system has been designed as a service-oriented architecture where Web services and Web services workflows are the basic building blocks. Articulated private networks are presented as the first services built upon the UCLPv2 network virtualization middleware. APNs can be considered as a next generation VPN where a user can create a complex, multi-domain network topology by binding together network resources, computers, time slices, and virtual or real routing and/or switching nodes. A first implementation of the UCLPv2 software was deployed on CAnet 4, Canada's research and education network, and currently, it is being used by Environment Canada, a federal government department, to enable an APN that links its research facilities across the country.

Web service workflow selection using system and network QoS constraints

Web services serve as a leading technology platform for web-based data-centric environments providing flexibility of loose coupling, message-based communication. Interest in more efficient web services selection strategies is rather requisite especially from the business process workflow perspective. We present several strategies to efficiently select a set of web services performing a workflow, fulfilling quality specifications at all workflow steps. The focus is on finding the best performing web service given a history of the execution times and current measured variation in operating system and network resource consumption. To assess their efficiency, we experimentally evaluate them and present comparative results, which strongly indicate that they can effectively reduce the overall workflow execution time in a web service-based workflow with QoS constraints. Approaches are presented for a number of workflows depending on their particular characteristics.

A Multiagent Approach for Configuring and Explaining Workflow of Semantic Web Services

In this article, we describe a multiagent application that configures Semantic Web services following a design problem solving method. For that, a propose-and-revise strategy was modeled and implemented in OWL-S. The other contribution of this method is the extension of OWL-S for recording the service execution flow followed by the agent. The trace of the agent’s reasoning is stored in node sets represented in a proof markup language, which make up a framework for explanations on the Web. The proposed approach is shown to be useful in the context of e-business where the workflow definition of services is automatically performed by the agents in order to configure a computer from a customer order.

DataBiNS: a BioMoby-based data-mining workflow for biological pathways and non-synonymous SNPs

DataBiNS is a custom-designed BioMoby Web Service workflow that integrates non-synonymous coding single nucleotide polymorphisms (nsSNPs) data with structure/function and pathway data for the relevant protein. A KEGG Pathway Identifier representing a specific human biological pathway initializes the DataBiNS workflow. The workflow retrieves a list of publications, gene ontology annotations and nsSNP information for each gene involved in the biological pathway. Manual inspection of output data from several trial runs confirms that all expected information is appropriately retrieved by the workflow services. The use of an automated BioMoby workflow, rather than manual 'surfing', to retrieve the necessary data, significantly reduces the effort required for functional interpretation of SNP data, and thus encourages more speculative investigation. Moreover, the modular nature of the individual BioMoby Services enables fine-grained reusing of each service in other workflows, thus reducing the effort required to achieve similar investigations in the future. The workflow is freely available as a Taverna SCUFL XML document at the iCAPTURE Centre web site, http://www.mrl.ubc.ca/who/who_bios_scott_tebbutt.shtml.

An Approach to Constructing Web Service Workflow Based on Business Spanning Graph

Based on the fact that Web service dynamically changes and rapidly increases in the Internet, a user-oriented service workflow constructing model is proposed. The same or similar function services are accumulated into a kind of service set in this model, which is organized by the spanning tree, and the business spanning graph is formed according to workflow's business logic relation. At the same time, on the basis of redefining the position, velocity, addition, subtraction and multiplication of particle swarm algorithm, combining with the cross and mutation operations in genetic algorithm, the QoS (quality of service)scheduling algorithm based on hybrid particle swarm optimization algorithm (HPSOA) is designed to satisfy different multi-QoS demands when Web service rapidly increases. Experimental results demonstrate that the constructing model could effectively shield the physical varieties and differences of Web service, and preferably combine the Web service resource in the Internet. It is suitable for the application demands in the virtual computing environment.

A high performance grid-web service framework for the identification of ‘conserved sequence tags’

The continuous increasing of computing power in biological research places a threshold to the single host use and suggests an approach based on distributed computing. An emerging solution is grid technology, which allows organization to make better use of existing computing resources by providing them with a single, transparent, aggregated source of computing power. Equally, bioinformatics analysis often involves many web services, allowing shared access to information and helping the biologist to design, describe, record complex experiments. A new generation of grid infrastructure, where web services are building blocks, allow managent of a web services workflow. This work shows a tool for the identification and functional annotation of ‘Conserved Sequence Tags’ (CSTs) through cross-species genome comparisons, deployed on a Grid System Architecture, based on Web Services concepts and technologies.

An agent-based Web service workflow model for inter-enterprise collaboration

Abstract The service-orientated computing paradigm is transforming traditional workflow management from a close and centralized control system into a worldwide dynamic business process. A complete workflow serving inter-enterprise collaboration should include both internal processes and ad hoc external processes. This paper presents an agent-based workflow model to address this challenge. In the proposed model, agent-based technology provides the workflow coordination at both inter- and intra-enterprise levels while Web service-based technology provides infrastructures for messaging, service description and workflow enactment. A proof-of-concept prototype system simulating the order entry, partner search and selection, and contracting in a virtual enterprise creation scenario is implemented to demonstrate the dynamic workflow definition and execution for inter-enterprise collaboration.

Discovering web service workflows using web services interaction mining

Recovering and analysis of workflows executed in Service-Oriented Systems (SOS) can be expected to gain more and more relevance in service-oriented information technology in the not so distant future. Our work attempts to perform workflow mining in logs provided by service-oriented architectures. Firstly, we introduce the idea of Web Services Interaction Mining (WSIM) and give an overview of related fields of research. Secondly, we propose a classification of SOS according to the log information they provide and analyse mining opportunities in the respective classes. To illustrate the potential of WSIM, we describe a complete workflow mining cycle in a SOS of very rich log information. Since such rich logs are often not available, we then direct our attention to mining in limited logs. We present our first steps towards a workflow mining algorithm, specifically tailored to Web Services (WS). We conclude with a discussion of open issues and future work.

Annotation, composition and invocation of semantic web services

The way that web services are currently being developed places them beside rather than within the existing World Wide Web. In this paper, we present an approach that combines the strength of the World Wide Web, viz. interlinked HTML pages for presentation and human consumption, with the strength of semantic web services, viz. support for semi-automatic composition and invocation of web services that have semantically heterogeneous descriptions. The objective we aim at eventually is that a human user e.g. a consultant or an administrator can seamlessly browse the existing World Wide Web and the emerging web services and that he can easily compose and invoke Web services on the fly. This paper presents our framework, OntoMat-Service, which trades off between having a reasonably easy to use interface for web services and the complexity of web service workflows. It is not our objective that everybody can produce arbitrarily complex workflows of web services with our tool, the OntoMat-Service-Browser. However, OntoMat-Service aims at a service web, where simple service flows are easily possible—even for the persons with not much technical background, while still allowing for difficult flows for the expert engineer.

Web Services Workflows—Composition, Co-Ordination, and Transactions in Service-Oriented Computing

Web services can be seen as a newly emerging research area for Service-oriented Computing and their implementation in Service-oriented Architectures. Web services are self-contained, self-describing modular applications or components providing services. Web services may be dynamically aggregated, composed, and enacted as Web services Workflows. This requires frameworks and interaction protocols for their co-ordination and transaction support. In a Service-oriented Computing setting, transactions are more complex, involve multiple parties (roles), span many organizations, and may be long-running, consisting of a highly decentralized service partner and performed by autonomous entities. A Service-oriented Transaction Model has to provide comprehensive support for long-running propositions including negotiations, conversations, commitments, contracts, tracking, payments, and exception handling. Current transaction models and mechanisms including their protocols and primitives do not sufficiently cater for quality-aware and long running transactions comprising loosely-coupled (federated) service partners and resources. Web services transactions require co-ordination behavior provided by a traditional transaction mechanism to control the operations and outcome of an application. Furthermore, Web services transactions require the capability to handle the co-ordination of processing outcomes or results from multiple services in a more flexible manner. This requires more relaxed forms of transactions—those that do not strictly have to abide by the ACID properties—such as loosely-coupled collaboration and workflows. Furthermore, there is a need to group Web services into applications that require some form of correlation, but do not necessarily require transactional behavior. The purpose of this paper is to provide a state-of-the-art review and overview of some proposed standards surrounding Web services composition, co-ordination, and transaction. In particular the Business Process Execution Language for Web services (BPEL4WS), its co-ordination, and transaction frameworks (WS-Co-ordination and WS-Transaction) are discussed.

Annotation, Composition and Invocation of Semantic Web Services

The way that web services are currently being developed places them beside rather than within the existing World Wide Web. In this paper, we present an approach that combines the strength of the World Wide Web, viz. interlinked HTML pages for presentation and human consumption, with the strength of semantic web services, viz. support for semi-automatic composition and invocation of web services that have semantically heterogeneous descriptions. The objective we aim at eventually is that a human user e.g. a consultant or an administrator can seamlessly browse the existing World Wide Web and the emerging web services and that he can easily compose and invoke Web services on the fly. This paper presents our framework, OntoMat-Service, which trades off between having a reasonably easy to use interface for web services and the complexity of web service workflows. It is not our objective that everybody can produce arbitrarily complex workflows of web services with our tool, the OntoMat-Service-Browser. However, OntoMat-Service aims at a service web, where simple service flows are easily possible–even for the persons with not much technical background, while still allowing for difficult flows for the expert engineer.

Development of Middle Agents Mediating Ubiquitous Environment and Web Services

According to the widespread use of Web Services, composition of multiple services is becoming a main issue. BPEL was proposed as a Web Services workflow language in this context. Then, in many cases we need much interactions between a service requester and a BPEL process execution engine. However for the end user under the ubiquitous environment where the service is executed with a cellular phone or PDA, the interaction means simply a burden. The reason is: (1)it is hard to carry out the operation manually, (2)a network connection is unstable, (3)a connection charge is relatively high. In this paper, we propose middle agents between ubiquitous users and Web Services. The agents analyze BPEL, extract the interaction which the ubiquitous users would need, then produce action operators. It makes a plan in order to achieve a service request from the user. Here the planning agent can reduce operations of the user by collecting the necessary information at the beginning which will be inputted during the IP execution. We show the architecture of the agents and an example regarding ATM service, then evaluate the number of inputs, the performance, and the quantity of data transmitted on network. Finally, we consider adaptability of this approach to generic BPEL flow.