Mourad Kmimech

Event-B Based Approach for Verifying Dynamic Composite Service Transactional Behavior

Verifying Web service composition in a dynamic environment remains one of the most difficult tasks despite the efforts and the previous proposed research works because new services can be composed during the execution step and others can automatically appear, disappear, or be updated. To achieve the Web service composition specification and verification, we introduce a new concept, called dynamic pattern. A dynamic pattern is an extension of a static one. Then, we propose to formalize dynamic Web Service composition in Event-B using dynamic patterns. The resulting model is progressively verified using proofs. We use animator of model (ProB) to detect a variety of problems, such as deadlocks or other unexpected behavior of a model.

Verifying Composite Service Transactional Behavior with EVENT-B

A key challenge of Web Service (WS) composition is how to ensure reliable execution. Due to their inherent autonomy and heterogeneity, it is difficult to reason about the behavior of service compositions especially in case of failures. Therefore, there is a growing interest for verification techniques which help to prevent service composition execution failures. In this paper, we present a proof and refinement based approach for the formal representation, verification and validation of Web Services transactional compositions using the Event-B method.

Towards an approach of formal verification of mediation protocol based on web services

SOA (Service Oriented Architecture) defines a new Web services cooperation paradigm in order to develop distributed applications using reusable services. The handling of such collaboration has different problems that lead to many research efforts. In this paper, we address the problem of Web service composition. Indeed, various heterogeneities can arise during the composition. The resolution of these heterogeneities, called mediation, is needed to achieve a service composition. In this paper, we propose a sound approach to formalize Web services composition mediation with the ADL (Architecture Description Language) ACME. To do so, we first model the meta model of composite service manager and mediation. Then we specify semi formal properties associated with this meta model using OCL (Object Constraint Language). Afterwards, we formalize the mediation protocol using Armani, which provides a powerful predicate language in order to ensure service execution reliability.

Towards an approach of formal verification of mediation protocol based on web services of MDE type

Purpose – The purpose of this paper is to formally verify the composition of web services to reduce inconsistencies in software architectures.Design/methodology/approach – In order to check the web services composition, the authors use a model‐driven engineering (MDE)‐based approach and to achieve the formalization of web service composition in ACME and check the consistency of this composition, the authors introduce the pattern mediation to formalize web services composition with the ADL ACME, using the concept of architectural style of ACME. Subsequently, a scenario shows how this style can be used in ACMEStudio to detect inconsistencies. The example shows a web travel organization application.Findings – The authors ensure reliability defined through non‐functional properties. To do so, use ACME was used to check assembling consistency of web service composition. In a second part, a SWC2ACME tool was designed and implemented to check if the web services meta‐model conforms to ACME model.Originality/valu...

Checking Component Assembly in Acme: An Approach Applied on UML 2.0 Components Model

The components based approach aims at the re-use by an easy components assembly. Vis-a-vis to the objects based approach, the component based approach moves the complexity of a graph of classes (hierarchy of classes and client relationship) to connection points of between the components. The principal lock of the components based approach is the difficulty of deduction of the components assembly properties from the components themselves taken individually. In this paper, we present an MDE (Model driven Engineering) checking approach of component assembly based on the ADL (Architecture Description language) Acme/Armani. The proposed approach can be applied on several component models such as UML 2.0. We aim to check the structural and non-functional properties on a component assembly. Thereafter, we apply the proposed checking approach to the UML 2.0 component model.

Verifying composite service transactional behavior with EVENT-B

A key challenge of Web Service (WS) composition is how to ensure reliable execution. Due to their inherent autonomy and heterogeneity, it is difficult to reason about the behavior of service compositions especially in case of failures. Therefore, there is a growing interest for verification techniques which help to prevent service composition execution failures. In this paper, we present a proof and refinement based approach for the formal representation, verification and validation of Web Services transactional compositions using the Event-B method.

Towards a Practical Approach to Check Service Component Architecture

The components based approach aims at the re-use by an easy components assembly. A coherent components assembly requires the verification of properties related to the consistency of interface, semantics, synchronization, and the non-functional. We aim at the checking of the structural and non-functional properties of a SCA (Service Component Architecture assembly) endowed with the non-functional properties described in a CQML type language. Our approach, which is based on an assembly by contracts established between components assembly. We propose to use the Acme/Armani ADL as contract definition language.

A Formal Approach for Verifying QoS Variability in Web Services Composition Using EVENT-B

The main issues for the fulfillment service level agreements (SLA) are concerned with problem of variability of QoS properties (vQoS). Indeed, the QoS properties may evolve frequently either because of internal changes or because of workload fluctuations. To solve the vQoS problem, we first introduced three variability operators: replicate, delete and replace. These operators will be used to reconfigure CWS when the SLA contract is violated. The first two operators are used to add and remove Web service instances, while the last one is used to substitute some faulty Web services. Then, we proposed an incremental approach for modeling and verifying the composites services (CWSs) reconfiguration using Event-B. We start by abstractly specifying the main requirements and then we refine them through several steps to model CWSs. The consistency of each model and the relationship between an abstract model and its refinements are obtained by formal proofs. Finally, we used ProB model-checker to trace possible design errors. We have exploited the LTL for dynamic reconfigurations to characterize the correct behavior of CWSs reconfiguration.

Modeling and Verifying the Transactional and QoS-aware Services Composition Using Event-B

Composite applications leveraging the functionalities offered by Web services are today the underpinnings of enterprise computing. However, current Web services composition systems make only use of functional requirements in the selection process of component Web services, while the transactional consistency and quality of service (QoS) are crucial parameters of most business applications. In this paper, we propose a novel approach for Web services selection and composition based on transactional requirements and QoS constraints. The transactional requirements are defined by the engineers using the acceptable termination states concept. We give a formalization of our approach in Event-B. We incrementally combine the modeling and verification activities related to formal development process supported by Event-B method. The verification activity is based on the proof and model-checking.

ATL Transformation for the Generation of SCA Model

Service Component Architecture specification (SCA) is an emerging and promising technology for the development, deployment and integration of Internet applications. This technology supports the management of dynamic availability and treats the heterogeneity between the components of distributed applications. However, this technology is not able to solve all problems. Currently, software systems are evolving. This factor makes development and maintenance of systems more complex than before. One solution to remedy this was the use of the Model Driven Engineering (MDE) approach in the development process. The aim of this paper is to apply an MDE automation type ensuring the passage from an UML 2.0 model to SCA model. To achieve this, we study two metamodels: the UML 2.0 component metamodel and the SCA meta-model. To ensure trace ability between these two meta-models, we have defined transformation rules in ATL language.