A Semantical Framework To Engineering WSBPEL Processes

International audienceWeb services promise the interoperability of various applications running on heterogeneous platforms over the Internet, and are gaining more and more attention. Web service composition refers to the process of combining Web services to provide value-added services, which has received much interest in supporting enterprize application integration. Industry standards for Web Service composition, such as WSBPEL, provide the notation and additional control mechanisms for the execution of business processes in Web service collaborations. However, these standards do not provide support for checking interesting properties related to Web Service and process behavior. In an attempt to fill this gap, we describe a formalization of WSBPEL business processes, that adds communications semantics to the specifications of interacting Web services, and uses a formal logic to model their dynamic behavior, which enables their formal analysis and the inference of relevant properties of the systems being built

Web Service Mining and Verification of Properties: An approach based on Event Calculus

http://www.springerlink.com/Web services are becoming more and more complex, involving numerous interacting business objects within complex distributed processes. In order to fully explore Web service business opportunities, while ensuring a correct and reliable execution, analyzing and tracking Web services interactions will enable them to be well understood and controlled. The work described in this paper is a contribution to these issues for Web services based process applications. This article describes a novel way of applying process mining techniques to Web services logs in order to enable ''Web service intelligence''. Our work attempts to apply Web service log-based analysis and process mining techniques in order to provide semantical knowledge about the context of and the reasons for discrepancies between process models and related instances

Towards Formal Verification of Web Service Composition

http://www.springerlink.com/Web services composition is an emerging paradigm for enabling application integration within and across organizational boundaries. Current Web services composition proposals, such as BPML, WSBPEL, WSCI, and OWL-S, provide solutions for describing the control and data flows in Web service composition. However, such proposals remain at the descriptive level, without providing any kind of mechanisms or tool support for analysis and verification. Therefore, there is a growing interest for the verification techniques which enable designers to test and repair design errors even before actual running of the service, or allow designers to detect erroneous properties and formally verify whether the service process design does have certain desired properties. In this paper, we propose to verify Web services composition using an event driven approach. We assume Web services that are coordinated by a composition process expressed in WSBPEL and we use Event Calculus to specify the properties and requirements to be monitored

An Event Based Model for Web Service Coordination

The promise of Web services is centered around standard and interoperable means for integrating loosely coupled Web based components that expose well-defined interfaces, while abstracting the implementation and platform specific details. The current and more mature core Web services standards SOAP, WSDL and UDDI provide a solid foundation to accomplish this. However, these specifications primarily enable development of simple Web services whereas the ultimate goal of Web services is to facilitate and automate business process collaborations both inside and outside enterprize boundaries. Useful business applications of Web services in B2B, B2C, and enterprize application integration environments will require the ability to compose complex and distributed Web services and the ability to formally describe the relationships between the constituent low-level services. This paper advocates an event-based approach for Web services coordination. We focused on reasoning about events to capture the semantics of complex Web service combinations. Then we present a formal language to specifying composite events for managing complex interactions amongst services, and detecting inconsistencies that may arise at run-time

Analysis of Composite Web Services using Logging Facilities

Web services are becoming more and more complex, involving numerous interacting business objects within considerable processes. In order to fully explore Web service business opportunities while ensuring a correct and reliable modelling and execution, analyzing and tracking Web services interactions will enable them to be well understood and controlled. Then, given the resulting event log we want to verify certain specified properties, to provide knowledge about the context of and the reasons for discrepancies between services'behaviours and related instances. This paper advocates a novel technique to log composite Web services and a formal approach, based on an algeabric specification of the discrete event calculus language DEC, to check behavioural properties of composite Web services regarding their execution log. An automated induction-based theorem prover SPIKE is used as verification back-end

Communications semantics for WSBPEL Processes

ISBN : 978-0-7695-3310-0International audienceWSBPEL opens up the possibility of applying a range of formal techniques to the verification of Web service behaviors from two points of view: constraints between activities within the same process and dependencies between activities of different processes. In a previous work, we have described an approach for the verification of Web service compositions defined by a set of BPEL processes. The key aspect of such a verification task is the model adopted for representing the communications among the services participating to the composition. In this paper, we propose to extend this approach to handle dependencies between activities of different process orchestrations through message exchanges. Our aim is to enable supporting models of service choreography with multiple interacting Web services compositions, from the perspective of a collaborative distributed composition development environment. The process of behavior analysis moves from a single local process to that of modelling and analyzing the behavior of multiple processes across composition domains

Web Services Compositions Modelling and Choreographies Analysis

International audienceIn (Rouached, Godart and al. 2006; Rouached, Godart 2007), we have described the semantics of WSBPEL by way of mapping each of the WSBPEL (Arkin, Askary and al. 2004) constructs to the EC algebra and building a model of the process behaviour. With these mapping rules, we have described a modelling approach of a process defined for a single Web service composition. However, this modelling is limited to a local view and can only be used to model the behaviour of a single process. A series of compositions in Web service choreography need specific modelling activities that are not explicitly derived from an implementation. An elaboration of modelling is then required to represent the behaviour of interacting compositions across partnered processes. This elaboration provides a representation that enables us to perform analysis of service interaction for behaviour properties. The ability to perform verification and validation between execution and design, and within the process compositions themselves, is a key requirement of the Web services architecture specification. In this paper, we further the semantic mapping to include Web service composition interactions through modelling Web service conversations and their choreography. We describe this elaboration of models to support a view of interacting Web service compositions extending the mapping from WSBPEL to EC, and including Web service interfaces (WSDL) for use in modelling between services. The verification and validation techniques are also exposed. An automated induction-based theorem prover is used as verification back-end

A rigourous approach for engineering web services compositions

L'évolution de l'Internet comme support de communication entre les applications et les organisations a révolutionné les méthodes de coopération classiques. Les technologies réseaux actuelles, notamment les services Web, permettent le développement de nouveaux paradigmes de coopération. En effet, les entreprises peuvent dans un premier temps externaliser leurs procédés métiers comme des services Web pour former dans un deuxième temps ce qu'on appelle une entreprise virtuelle par compositions de services externalisés. Mais, comme souvent en informatique, ce qui est supposé apporter de la facilité apporte aussi son lot de complexité et de questions. Cela va de la pertinence des langages utilisés pour décrire les compositions de services, leur formalisation, leur vérification formelle avant et après l'exécution, au problème de maintenir une qualité de services constante. L'objectif de cette thèse est de proposer une approche rigoureuse pour la spécification, la modélisation, la vérification et la validation des compositions de services Web. Le travail effectué a permis la mise en place de techniques de preuves pour les services Web pour répondre à de nouveaux challenges liés essentiellement à la composition et la vérification. L'approche développée consiste en : (i)la définition d'un langage de spécification de la composition pour assurer sa vérification formelle, (ii) l'extension du langage de composition transformé pour prendre en compte les aspects de communication entre des compositions différentes, (iii) l'extraction et la spécification des propriétés à vérifier avant et après l'exécution de la composition, (iv) la vérification de la composition (vérification a priori et vérification a posteriori), et (v) l'utilisation des spécifications des déviations détectées pour découvrir des services qui peuvent tomber en panne ou devenir indisponibles en cours d'exécution.The proliferation of the Internet as a communication medium between applications and organizations has revolutionized the classic methods of cooperation. The current network technologies, including Web services, allow the development of new paradigms of cooperation. Indeed, enterprises can outsource their business processes as Web services to form what is called a virtual enterprise by compositions of outsourced services. However, as so often in computer science applications, which is supposed to bring the facility provides also its set of complexity and questions. This covers the relevance of the language used to describe the compositions of services, their formalizations, their formal verification before and after running the composition process, and the need of maintaining a constant quality of services. The aim of this dissertation is to develop a rigorous approach to specifying, modelling, verifying and validating the behaviour of Web service compositions with the goal of simplifying the task of designing coordinated distributed services and their interaction requirements. More precisely, we have proposed a semantic framework that provides a foundation for addressing the existing limitations in the context of Web services compositions by supporting the following functionalities: (i) to formally specify requirements for BPEL processes. The requirements specify behavioural properties of the composition process, or assumptions about the behaviour of the composition as a whole and its constituent services, (ii) to extend the approach to include models of service choreography with multiple interacting Web services compositions, from the perspective of a collaborative distributed composition development environment, (iii) to verify these requirements against process executions. The requirements verification can be done either a-priori, i.e., at design time, or a-posteriori, i.e., after runtime, (iv) to use the specifications of the violated requirements to generate queries for discovering services that could substitute for malfunctioning services or services that may become unavailable or fail to meet certain requirements

Une approche rigoureuse pour l'ingénierie de compositions de services Web

L'évolution de l'Internet comme support de communication entre les applications et les organisations a révolutionné les méthodes de coopération classiques. Les technologies réseaux actuelles, notamment les services Web, permettent le développement de nouveaux paradigmes de coopération. En effet, les entreprises peuvent dans un premier temps externaliser leurs procédés métiers comme des services Web pour former dans un deuxième temps ce qu'on appelle une entreprise virtuelle par compositions de services externalisés. Mais, comme souvent en informatique, ce qui est supposé apporter de la facilité apporte aussi son lot de complexité et de questions. Cela va de la pertinence des langages utilisés pour décrire les compositions de services, leur formalisation, leur vérification formelle avant et après l'exécution, au problème de maintenir une qualité de services constante. L'objectif de cette thèse est de proposer une approche rigoureuse pour la spécification, la modélisation, la vérification et la validation des compositions de services Web. Le travail effectué a permis la mise en place de techniques de preuves pour les services Web pour répondre à de nouveaux challenges liés essentiellement à la composition et la vérification. L'approche développée consiste en : (i)la définition d'un langage de spécification de la composition pour assurer sa vérification formelle, (ii) l'extension du langage de composition transformé pour prendre en compte les aspects de communication entre des compositions différentes, (iii) l'extraction et la spécification des propriétés à vérifier avant et après l'exécution de la composition, (iv) la vérification de la composition (vérification a priori et vérification a posteriori), et (v) l'utilisation des spécifications des déviations détectées pour découvrir des services qui peuvent tomber en panne ou devenir indisponibles en cours d'exécution.The proliferation of the Internet as a communication medium between applications and organizations has revolutionized the classic methods of cooperation. The current network technologies, including Web services, allow the development of new paradigms of cooperation. Indeed, enterprises can outsource their business processes as Web services to form what is called a virtual enterprise by compositions of outsourced services. However, as so often in computer science applications, which is supposed to bring the facility provides also its set of complexity and questions. This covers the relevance of the language used to describe the compositions of services, their formalizations, their formal verification before and after running the composition process, and the need of maintaining a constant quality of services. The aim of this dissertation is to develop a rigorous approach to specifying, modelling, verifying and validating the behaviour of Web service compositions with the goal of simplifying the task of designing coordinated distributed services and their interaction requirements. More precisely, we have proposed a semantic framework that provides a foundation for addressing the existing limitations in the context of Web services compositions by supporting the following functionalities: (i) to formally specify requirements for BPEL processes. The requirements specify behavioural properties of the composition process, or assumptions about the behaviour of the composition as a whole and its constituent services, (ii) to extend the approach to include models of service choreography with multiple interacting Web services compositions, from the perspective of a collaborative distributed composition development environment, (iii) to verify these requirements against process executions. The requirements verification can be done either a-priori, i.e., at design time, or a-posteriori, i.e., after runtime, (iv) to use the specifications of the violated requirements to generate queries for discovering services that could substitute for malfunctioning services or services that may become unavailable or fail to meet certain requirements.NANCY1-Bib. numérique (543959902) / SudocSudocFranceF