Planning and Specifying the Composition of Web Services

As the Web services paradigm becomes popular and more and more applications are created and deployed as Web services, the need for developing new solutions tackling the composition of Web services becomes manifest. However, emerging web service standards and existing methods are not sufficient for realizing the goal of flexible and dynamic composition of Web services, although some preliminary work has been conducted in the area of services composition. This situation has raised the interesting research points for creating and developing new approaches for the Web services composition. In this paper we separate the design and implementation phases of the composite services, and concentrate on the research of the way a composite service is constructed in terms of its constituent services. We call this way the composition logic of a composite service. We firstly propose well-defined notions “composition structures” to represent the joints among the constituent services and generate the reliable structure of a composite service, and then we provide a specification mechanism to clearly specify the internal dependencies of a composite service in terms of the notification and dataflow dependencies. Our solutions for planning and specifying the composition of Web services can effectively support the properties of modularity, interoperability, dynamic reconfigure-ability and fault-tolerance for a composite software system in the dynamic Web environments of business applications, which are a organic part of our framework for tackling the challenges of Web service discovery and composition on which we are working

Synthesis of underspecified composite e

In this paper we study automatic composition synthesis of e-Services, based on automated reasoning. We represent the behavior of an e-Service in terms of a deterministic transition syst (or a finite state machine), in which for each action the role of the e-Service, either as initiator or as servant, is highlighted. In this setting we present an algorithm based on satisfiability in a variant of Propositional Dynamic Logic that solves the automatic composition probl. Specifically, given (i) a possibly incomplete specification of the sequences of actions that a client would like to realize, and (ii) a set of available e-Services, our technique synthesizes a composite e-Service that (i) uses only the available e-Services and (ii) interacts with the client "in accordance" to the given specification. We also study the computational complexity of the proposed algorithm

Ontology-based composition and matching for dynamic cloud service coordination

Recent cross-organisational software service offerings, such as cloud computing, create higher integration needs. In particular, services are combined through brokers and mediators, solutions to allow individual services to collaborate and their interaction to be coordinated are required. The need to address dynamic management - caused by cloud and on-demand environments - can be addressed through service coordination based on ontology-based composition and matching techniques. Our solution to composition and matching utilises a service coordination space that acts as a passive infrastructure for collaboration where users submit requests that are then selected and taken on by providers. We discuss the information models and the coordination principles of such a collaboration environment in terms of an ontology and its underlying description logics. We provide ontology-based solutions for structural composition of descriptions and matching between requested and provided services

Modal logics for reasoning about object-based component composition

Component-oriented development of software supports the adaptability and maintainability of large systems, in particular if requirements change over time and parts of a system have to be modified or replaced. The software architecture in such systems can be described by components and their composition. In order to describe larger architectures, the composition concept becomes crucial. We will present a formal framework for component composition for object-based software development. The deployment of modal logics for defining components and component composition will allow us to reason about and prove properties of components and compositions

Semantic model-driven development of web service architectures.

Building service-based architectures has become a major area of interest since the advent of Web services. Modelling these architectures is a central activity. Model-driven development is a recent approach to developing software systems based on the idea of making models the central artefacts for design representation, analysis, and code generation. We propose an ontology-based engineering methodology for semantic model-driven composition and transformation of Web service architectures. Ontology technology as a logic-based knowledge representation and reasoning framework can provide answers to the needs of sharable and reusable semantic models and descriptions needed for service engineering. Based on modelling, composition and code generation techniques for service architectures, our approach provides a methodological framework for ontology-based semantic service architecture

An ontology for software component matching

The Web is likely to be a central platform for software development in the future. We investigate how Semantic Web technologies, in particular ontologies, can be utilised to support software component development in a Web environment. We use description logics, which underlie Semantic Web ontology languages such as DAML+OIL, to develop an ontology for matching requested and provided components. A link between modal logic and description logics will prove invaluable for the provision of reasoning support for component and service behaviour

Specification and Verification of Context-dependent Services

Current approaches for the discovery, specification, and provision of services ignore the relationship between the service contract and the conditions in which the service can guarantee its contract. Moreover, they do not use formal methods for specifying services, contracts, and compositions. Without a formal basis it is not possible to justify through formal verification the correctness conditions for service compositions and the satisfaction of contractual obligations in service provisions. We remedy this situation in this paper. We present a formal definition of services with context-dependent contracts. We define a composition theory of services with context-dependent contracts taking into consideration functional, nonfunctional, legal and contextual information. Finally, we present a formal verification approach that transforms the formal specification of service composition into extended timed automata that can be verified using the model checking tool UPPAAL.Comment: In Proceedings WWV 2011, arXiv:1108.208