The Experts below are selected from a list of 31434 Experts worldwide ranked by ideXlab platform

Maria Bielikova - One of the best experts on this subject based on the ideXlab platform.

  • qos aware semantic web Service composition approach considering pre postconditions
    International Conference on Web Services, 2010
    Co-Authors: Peter Bartalos, Maria Bielikova
    Abstract:

    Web Service composition is a topic bringing several issues to be resolved. Our work deals with the effectiveness and scalability of Service composition. During composition we consider QoS and pre-/post-conditions of single Services to create a Composite Service satisfying the user needs the best. Regarding pre-/post-conditions we propose an approach to fast determination of which Services produce results expected by the user, i.e. the post-condition of which Services implicates the desired condition defined in the user goal. This paper proposes also an approach to restriction on the Service space which provided a dramatic improvement in terms of composition time.

  • semantic web Service composition framework based on parallel processing
    Congress on Evolutionary Computation, 2009
    Co-Authors: Peter Bartalos, Maria Bielikova
    Abstract:

    The process of semantic web Service composition arranges several web Services into one Composite Service to realize complex workflows with an exploitation of semantics. This paper proposes a framework to automatic semantic web Service composition. Its advantage is that a huge amount of computation is performed during preprocessing and the composition approach is designed to exploit the parallel execution of processes which is nowadays supported in multiprocessor platforms. The framework is built to suit the WS Challenge competition requirements.

  • fast and scalable semantic web Service composition approach considering complex pre postconditions
    IEEE Congress on Services, 2009
    Co-Authors: Peter Bartalos, Maria Bielikova
    Abstract:

    The process of semantic web Service composition arranges several web Services into one Composite Service to realize complex workflows with an exploitation of semantics. This paper proposes an approach to automatic semantic web Service composition. Its advantage is good scalability regarding the complexity of user constraints and pre/post conditions. Based on these conditions it propagates the value restrictions constraint from the user goal through the overall Composite Service. The resulting plan depicts all the possible branches of the workflow leading to a goal. This includes the automatic generation of the conditions deciding which branch will be chosen during the execution. Finally, our approach exploits available data which can be used as input parameters for web Services. If these are not offered, it searches for a web Service producing them.

Peter Bartalos - One of the best experts on this subject based on the ideXlab platform.

  • qos aware semantic web Service composition approach considering pre postconditions
    International Conference on Web Services, 2010
    Co-Authors: Peter Bartalos, Maria Bielikova
    Abstract:

    Web Service composition is a topic bringing several issues to be resolved. Our work deals with the effectiveness and scalability of Service composition. During composition we consider QoS and pre-/post-conditions of single Services to create a Composite Service satisfying the user needs the best. Regarding pre-/post-conditions we propose an approach to fast determination of which Services produce results expected by the user, i.e. the post-condition of which Services implicates the desired condition defined in the user goal. This paper proposes also an approach to restriction on the Service space which provided a dramatic improvement in terms of composition time.

  • semantic web Service composition framework based on parallel processing
    Congress on Evolutionary Computation, 2009
    Co-Authors: Peter Bartalos, Maria Bielikova
    Abstract:

    The process of semantic web Service composition arranges several web Services into one Composite Service to realize complex workflows with an exploitation of semantics. This paper proposes a framework to automatic semantic web Service composition. Its advantage is that a huge amount of computation is performed during preprocessing and the composition approach is designed to exploit the parallel execution of processes which is nowadays supported in multiprocessor platforms. The framework is built to suit the WS Challenge competition requirements.

  • fast and scalable semantic web Service composition approach considering complex pre postconditions
    IEEE Congress on Services, 2009
    Co-Authors: Peter Bartalos, Maria Bielikova
    Abstract:

    The process of semantic web Service composition arranges several web Services into one Composite Service to realize complex workflows with an exploitation of semantics. This paper proposes an approach to automatic semantic web Service composition. Its advantage is good scalability regarding the complexity of user constraints and pre/post conditions. Based on these conditions it propagates the value restrictions constraint from the user goal through the overall Composite Service. The resulting plan depicts all the possible branches of the workflow leading to a goal. This includes the automatic generation of the conditions deciding which branch will be chosen during the execution. Finally, our approach exploits available data which can be used as input parameters for web Services. If these are not offered, it searches for a web Service producing them.

Mengchu Zhou - One of the best experts on this subject based on the ideXlab platform.

  • automatic web Service composition based on horn clauses and petri nets
    Expert Systems With Applications, 2011
    Co-Authors: Xianfei Tang, Changjun Jiang, Mengchu Zhou
    Abstract:

    This paper introduces an automatic Web Service composition method based on logical inference of Horn clauses and Petri nets. The Web Service composition problem is transformed into the logical inference problem of Horn clauses by exploring the dependency relations among Services. An algorithm is presented, to determine whether the Composite Service exists in time that is linear in the size of the knowledge base. It can also return the rule set necessary for the composition. Petri nets are chosen to model the rule set and its structural analysis techniques are used to obtain the Composite Service.

  • Automated web Service composition supporting conditional branch structures
    Enterprise Information Systems, 2011
    Co-Authors: Pengwei Wang, Ding Zhijun, Changjun Jiang, Mengchu Zhou
    Abstract:

    The creation of value-added Services by automatic composition of existing ones is gaining a significant momentum as the potential silver bullet in Service-oriented architecture. However, Service composition faces two aspects of difficulties. First, users' needs present such characteristics as diversity, uncertainty and personalisation; second, the existing Services run in a real-world environment that is highly complex and dynamically changing. These difficulties may cause the emergence of nondeterministic choices in the process of Service composition, which has gone beyond what the existing automated Service composition techniques can handle. According to most of the existing methods, the process model of Composite Service includes sequence constructs only. This article presents a method to introduce conditional branch structures into the process model of Composite Service when needed, in order to satisfy users' diverse and personalised needs and adapt to the dynamic changes of real-world environment. UML activity diagrams are used to represent dependencies in Composite Service. Two types of user preferences are considered in this article, which have been ignored by the previous work and a simple programming language style expression is adopted to describe them. Two different algorithms are presented to deal with different situations. A real-life case is provided to illustrate the proposed concepts and methods.

Mohsen Rouached - One of the best experts on this subject based on the ideXlab platform.

  • event based design and runtime verification of Composite Service transactional behavior
    IEEE Transactions on Services Computing, 2010
    Co-Authors: Walid Gaaloul, Sami Bhiri, Mohsen Rouached
    Abstract:

    Different from process components, Web Services are defined independently from any execution context. A key challenge of (Web) Service compositions 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 propose an event-driven approach to validate the transactional behavior of Service compositions. The transactional behavior verification is done either at design time to validate recovery mechanisms consistency, or after runtime to report execution deviations and repair design errors, and therefore, formally ensure Service execution reliability. By using the Event Calculus formalism to specify and check the transactional behavior consistency of Service composition, our approach provides a logical foundation to ensure Service execution reliability.

  • verifying Composite Service transactional behavior using event calculus
    International Conference on Move to Meaningful Internet Systems, 2007
    Co-Authors: Walid Gaaloul, Mohsen Rouached, Claude Godart, Manfred Hauswirth
    Abstract:

    A key challenge ofWeb Service (WS) composition is how to ensure reliable execution. The lack of techniques that support non-functional features such as execution reliability is widely recognized as a barrier preventing widespread adoption. Therefore, there is a growing interest for verification techniques which help to prevent WS composition execution failures. In this paper, we propose an event driven approach to validate the transactional behavior of WS compositions. Using the Event Calculus to formally specify and check the transactional behavior consistency of WS composition, our approach provides a logical foundation to ensure recovery mechanisms consistency at design time and report execution deviations after runtime.

Marlon Dumas - One of the best experts on this subject based on the ideXlab platform.

  • Heuristics for Composite Web Service decentralization
    Software & Systems Modeling, 2014
    Co-Authors: Walid Fdhila, Marlon Dumas, Claude Godart, Luciano García-bañuelos
    Abstract:

    A Composite Service is usually specified by means of a process model that captures control-flow and data-flow relations between activities that are bound to underlying component Services. In mainstream Service orchestration platforms, this process model is executed by a centralized orchestrator through which all interactions are channeled. This architecture is not optimal in terms of communication overhead and has the usual problems of a single point of failure. In previous work, we proposed a method for executing Composite Services in a decentralized manner. However, this and similar methods for decentralized Composite Service execution do not optimize the communication overhead between the Services participating in the composition. This paper studies the problem of optimizing the selection of Services assigned to activities in a decentralized Composite Service, both in terms of communication overhead and overall quality of Service, and taking into account collocation and separation constraints that may exist between activities in the Composite Service. This optimization problem is formulated as a quadratic assignment problem. The paper puts forward a greedy algorithm to compute an initial solution as well as a tabu search heuristic to identify improved solutions. An experimental evaluation shows that the tabu search heuristic achieves significant improvements over the initial greedy solution. It is also shown that the greedy algorithm combined with the tabu search heuristic scale up to models of realistic size.

  • generalized aggregate quality of Service computation for Composite Services
    Journal of Systems and Software, 2012
    Co-Authors: Yong Yang, Marlon Dumas, Luciano Garciabanuelos, Artem Polyvyanyy, Liang Zhang
    Abstract:

    This article addresses the problem of estimating the Quality of Service (QoS) of a Composite Service given the QoS of the Services participating in the composition. Previous solutions to this problem impose restrictions on the topology of the orchestration models, limiting their applicability to well-structured orchestration models for example. This article lifts these restrictions by proposing a method for aggregate QoS computation that deals with more general types of unstructured orchestration models. The applicability and scalability of the proposed method are validated using a collection of models from industrial practice.

  • aggregate quality of Service computation for Composite Services
    Science & Engineering Faculty, 2010
    Co-Authors: Marlon Dumas, Yong Yang, Luciano Garciabanuelos, Artem Polyvyanyy, Liang Zhang
    Abstract:

    This paper addresses the problem of computing the aggregate QoS of a Composite Service given the QoS of the Services participating in the composition. Previous solutions to this problem are restricted to Composite Services with well-structured orchestration models. Yet, in existing languages such as WS-BPEL and BPMN, orchestration models may be unstructured. This paper lifts this limitation by providing equations to compute the aggregate QoS for general types of irreducible unstructured regions in orchestration models. In conjunction with existing algorithms for decomposing business process models into single-entry-single-exit regions, these functions allow us to cover a larger set of orchestration models than existing QoS aggregation techniques.

  • QoS-aware middleware for Web Services composition
    IEEE Transactions on Software Engineering, 2004
    Co-Authors: Liangzhao Zeng, Bouallem Benatallah, Anne H.h. Ngu, Jayant Kalagnanam, Marlon Dumas, Henry Chang
    Abstract:

    The paradigmatic shift from a Web of manual interactions to a Web of programmatic interactions driven by Web Services is creating unprecedented opportunities for the formation of online business-to-business (B2B) collaborations. In particular, the creation of value-added Services by composition of existing ones is gaining a significant momentum. Since many available Web Services provide overlapping or identical functionality, albeit with different quality of Service (QoS), a choice needs to be made to determine which Services are to participate in a given Composite Service. This paper presents a middleware platform which addresses the issue of selecting Web Services for the purpose of their composition in a way that maximizes user satisfaction expressed as utility functions over QoS attributes, while satisfying the constraints set by the user and by the structure of the Composite Service. Two selection approaches are described and compared: one based on local (task-level) selection of Services and the other based on global allocation of tasks to Services using integer programming.

  • Quality driven web Services composition
    Proceedings of the twelfth international conference on World Wide Web WWW 03, 2003
    Co-Authors: Liangzhao Zeng, Bouallem Benatallah, Jr Votano, Jayant Kalagnanam, Mary Parham, Marlon Dumas, Quan Z Sheng, Lh Hall
    Abstract:

    The process-driven composition of Web Services is emerging as a promising approach to integrate business applications within and across organizational boundaries. In this approach, individual Web Services are federated into Composite Web Services whose business logic is expressed as a process model. The tasks of this process model are essentially invocations to functionalities offered by the underlying component Services. Usually, several component Services are able to execute a given task, although with different levels of pricing and quality. In this paper, we advocate that the selection of component Services should be carried out during the execution of a Composite Service, rather than at design-time. In addition, this selection should consider multiple criteria (e.g., price, duration, reliability), and it should take into account global constraints and preferences set by the user (e.g., budget constraints). Accordingly, the paper proposes a global planning approach to optimally select component Services during the execution of a Composite Service. Service selection is formulated as an optimization problem which can be solved using efficient linear programming methods. Experimental results show that this global planning approach outperforms approaches in which the component Services are selected individually for each task in a Composite Service.