Boualem Benatallah

QoS-aware middleware for Web services composition

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

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.

The Self-Serv environment for Web services composition

Self-Serv aims to enable the declarative composition of new services from existing ones, the multiattribute dynamic selection of services within a composition, and peer-to-peer orchestration of composite service executions. Self-Serv adopts the principle that every service, whether elementary or composite, should provide a programmatic interface based on SOAP and the Web Service Definition Language. This does not exclude the possibility of integrating legacy applications, such as those written in CORBA, into the services business logic. To integrate such applications, however, first requires the development of appropriate adapters. The paper considers how the mechanism for composing services in Self-Serv is based on two major concepts: the composite service and the service container.

Declarative composition and peer-to-peer provisioning of dynamic Web services

The development of new services through the integration of existing ones has gained a considerable momentum as a means to create and streamline business-to-business collaborations. Unfortunately, as Web services are often autonomous and heterogeneous entities, connecting and coordinating them in order to build integrated services is a delicate and time-consuming task. In this paper, we describe the design and implementation of a system through which existing Web services can be declaratively composed, and the resulting composite services can be executed following a peer-to-peer paradigm, within a dynamic environment. This system provides tools for specifying composite services through. statecharts, data conversion rules, and provider selection, policies. These specifications are then translated into XML documents that can be interpreted by peer-to-peer inter-connected software components, in order to provision the composite service without requiring a central authority.

Business-to-business interactions: issues and enabling technologies

Abstract. Business-to-Business (B2B) technologies pre-date the Web. They have existed for at least as long as the Internet. B2B applications were among the first to take advantage of advances in computer networking. The Electronic Data Interchange (EDI) business standard is an illustration of such an early adoption of the advances in computer networking. The ubiquity and the affordability of the Web has made it possible for the masses of businesses to automate their B2B interactions. However, several issues related to scale, content exchange, autonomy, heterogeneity, and other issues still need to be addressed. In this paper, we survey the main techniques, systems, products, and standards for B2B interactions. We propose a set of criteria for assessing the different B2B interaction techniques, standards, and products.

Understanding Mashup Development

Web mashups are Web applications developed using contents and services available online. Despite rapidly increasing interest in mashups, comprehensive development tools and frameworks are lacking, and in most cases mashing up a new application implies a significant manual programming effort. This article overviews current tools, frameworks, and trends that aim to facilitate mashup development. The authors use a set of characteristic dimensions to highlight the strengths and weaknesses of some representative approaches.

Developing adapters for web services integration

The push toward business process automation has generated the need for integrating different enterprise applications involved in such processes. The typical approach to integration and to process automation is based on the use of adapters and message brokers. The need for adapters in Web services mainly comes from two sources: one is the heterogeneity at the higher levels of the interoperability stack, and the other is the high number of clients, each of which can support different interfaces and protocols, thereby generating the need for providing multiple interfaces to the same service. In this paper, we characterize the problem of adaptation of web services by identifying and classifying different kinds of adaptation requirements. Then, we focus on business protocol adapters, and we classify the different ways in which two protocols may differ. Next, we propose a methodology for developing adapters in Web services, based on the use of mismatch patterns and service composition technologies.

Service-Oriented Computing - ICSOC 2005

Vision Papers.- Autonomic Web Processes.- The (Service) Bus: Services Penetrate Everyday Life.- Service Oriented Architectures for Science Gateways on Grid Systems.- Service Specification and Modelling.- Toward a Programming Model for Service-Oriented Computing.- Speaking a Common Language: A Conceptual Model for Describing Service-Oriented Systems.- A Rule Driven Approach for Developing Adaptive Service Oriented Business Collaboration.- Service Design and Validation.- Pattern-Based Specification and Validation of Web Services Interaction Properties.- Using Test Cases as Contract to Ensure Service Compliance Across Releases.- Towards a Classification of Web Service Feature Interactions.- Service Selection and Discovery.- A High-Level Functional Matching for Semantic Web Services.- Service Selection Algorithms for Composing Complex Services with Multiple QoS Constraints.- On Service Discovery Process Types.- SPiDeR: P2P-Based Web Service Discovery.- An Approach to Temporal-Aware Procurement of Web Services.- Service Composition and Aggregation.- Approaching Web Service Coordination and Composition by Means of Petri Nets. The Case of the Nets-Within-Nets Paradigm.- Modeling and Analyzing Context-Aware Composition of Services.- Towards Semi-automated Workflow-Based Aggregation of Web Services.- Choreography and Orchestration: A Synergic Approach for System Design.- Service Monitoring.- PerfSONAR: A Service Oriented Architecture for Multi-domain Network Monitoring.- DySOA: Making Service Systems Self-adaptive.- Towards Dynamic Monitoring of WS-BPEL Processes.- Service Management.- Template-Based Automated Service Provisioning - Supporting the Agreement-Driven Service Life-Cycle.- Proactive Management of Service Instance Pools for Meeting Service Level Agreements.- Adaptive Component Management Service in ScudWare Middleware for Smart Vehicle Space.- Semantic Web and Grid Services.- Semantic Caching for Web Services.- ODEGSG Framework, Knowledge-Based Annotation and Design of Grid Services.- Implicit Service Calls in ActiveXML Through OWL-S.- Semantic Tuplespace.- Security, Exception Handling, and SLAs.- Trust-Based Secure Workflow Path Construction.- Reputation-Based Service Level Agreements for Web Services.- Handling Faults in Decentralized Orchestration of Composite Web Services.- Whats in an Agreement?An Analysis and an Extension of WS-Agreement.- Industrial and Application Papers.- SOA in the Real World - Experiences.- Service-Oriented Design: The Roots.- A Service Oriented Architecture for Deploying and Managing Network Services.- Demo Papers.- Dynamo: Dynamic Monitoring of WS-BPEL Processes.- WofBPEL: A Tool for Automated Analysis of BPEL Processes.- OpenWS-Transaction: Enabling Reliable Web Service Transactions.- ASTRO: Supporting Composition and Execution of Web Services.- Demonstrating Dynamic Configuration and Execution of Web Processes.- Short Papers.- Programming and Compiling Web Services in GPSL.- Semantic Management of Web Services.- Composition of Services with Nondeterministic Observable Behavior.- Efficient and Transparent Web-Services Selection.- An Approach to Parameterizing Web Service Flows.- Dynamic Policy Management on Business Performance Management Architecture.- A Lightweight Formal Framework for Service-Oriented Applications Design.- A MDE Approach for Power Distribution Service Development.- Semantic Web Services for Activity-Based Computing.- The Price of Services.- Managing End-to-End Lifecycle of Global Service Policies.- Applying a Web Engineering Method to Design Web Services.- An Architecture for Unifying Web Services Authentication and Authorization.- Specifying Web Service Compositions on the Basis of Natural Language Requests.

ContextUML: a UML-based modeling language for model-driven development of context-aware Web services

Context-aware Web services are emerging as a promising technology for the electronic businesses in mobile and pervasive environments. Unfortunately, complex context-aware services are still hard to build. In this paper, we present a modeling language for the model-driven development of context-aware Web services based on the Unified Modeling Language (UML). Specifically, we show how UML can be used to specify information related to the design of context-aware services. We present the abstract syntax and notation of the language and illustrate its usage using an example service. Our language offers significant design flexibility that considerably simplifies the development of context-aware Web services.

On automating Web services discovery

Abstract.One of the challenging problems that Web service technology faces is the ability to effectively discover services based on their capabilities. We present an approach to tackling this problem in the context of description logics (DLs). We formalize service discovery as a new instance of the problem of rewriting concepts using terminologies. We call this new instance the best covering problem. We provide a formalization of the best covering problem in the framework of DL-based ontologies and propose a hypergraph-based algorithm to effectively compute best covers of a given request. We propose a novel matchmaking algorithm that takes as input a service request (or query) Q and an ontology