Automating Web Service Composition

2011

Abstract. The aim of Web service composition is to arrange multiple services into workflows supplying complex user needs. Due to the huge amount of Web services and the need to supply dynamically varying user goals, it is necessary to perform the composition automatically. The objective of this article is to overview the issues of automatic dynamic Web service composition. We discuss the issues related to the semantics of services, which is important for automatic Web service composition.

Proceedings of the Fourth International Conference on Web Information Systems and Technologies, 2008

Web services are software components that were designed to improve interoperability and integration of applications developed on different platforms. Web Service composition offers the facility to create new services out of the existing services satisfying a complex functionality. This paper presents HARMONY, a framework for automatic Web service composition. Our approach for automatic Web service composition is based on the GraphPlan algorithm. In HARMONY we use ontologies for the semantic annotation of Web services, so that the automatic service discovery, composition and execution can be realized based on ontology inference.

Electronics and Electrical Engineering, 2013

OWLS , one of the most significant Semantic web service ontologies , provides Web Service providers with a core ontological framework and guidelines for describing the properties and capabilities of their web Services in unambiguous, computer interpretable form. In this work we present a translation-based approach for modelling the semantic Web services described in the OWLS language. This approach employs Petri net as the fundamental means of modelling and defines a set of translation rules to map OWLS elements into equivalent Petri net representations. They capture the main aspect of service invocations and the control flow of the service model. A case study based on a real-world OWLS example is also conducted to examine the effectiveness of the translation-based model.

Lecture Notes in Computer Science, 2009

One of the key ideas underlying Web services is that of allowing the combination of existing services published on the Web into a new service that achieves some higher-level functionality and satisfies some business goals. As the manual development of the new composite service is recognized as a difficult and error-prone task, the automated synthesis of the composition is considered one of the key challenges in the field of Web services. In this paper, we will present a survey of existing approaches for the synthesis of Web service compositions. We will then focus on a specific approach, the ASTRO approach, which has been shown to support complex composition requirements and to be applicable in real domains. In the paper, we will present the formal framework behind the ASTRO approach; we will present the implementation of the framework and its integration within a commercial toolkit for developing Web services; we will finally evaluate the approach on a real-world composition domain. A wide variety of approach has been proposed in the scientific literature for addressing the problem of Web service composition-we will provide a survey in this paper. Here we will focus on a specific approach to Web service composition, namely the ASTRO approach (see http://www.astroproject.org). This approach starts from the observation that, in most real-life scenarios, services are stateful and realize complex protocols (e.g., a multi-phase booking procedure includes search, selection, and checkout tasks); their behaviour may be non-deterministic (the search may provide no result, checkout may fail), and they may exchange messages asynchronously. The synthesis of a Web service composition in this setting consists in understanding how to orchestrate the interactions among the component services, so that their protocols are respected, all non-deterministic outcomes are covered, and the composition requirement is achieved. More precisely, in this paper we present a formal framework for the automated composition of Web services that is able to cope with complex control and data flows, i.e., with Web services exposing complex protocols and exchanging structured data, and with composition requirements expressing constraints not only on the service interactions but also on the exchanged data. The framework is based on a model for Web services that is able to overcome the limitations of the existing approaches and to capture the complex protocols and data structures of services in real domains. For what concerns the specification of composition requirements, the framework provides advanced formal languages for specifying constraints both on the control flow and on the data flow. The framework is implemented and integrated in a toolkit that allows for automatically composing Web services. In the paper, we will also describe the toolkit and its application on a on real-world composition domains. The structure of the paper is as follows. Section 2 provides a survey of the existing approaches for the composition of Web services. Section 3 illustrates the problem of synthesising the composition of stateful Web services through a simple example based on a Virtual Travel Agency. Section 4 introduces the formal model for Web service compositions; this model allows for specifying stateful component services, as well as composition requirements on the control-flow and on the data-flow. Section 5 shows how the synthesis of the service composition can be achieved by exploiting an existing approach for planning in asynchronous domains. Section 6 introduces a tool for Web service composition which implements the model and the automated synthesis approach described in the previous sections. Section 7 evaluates the approach on a real problem of service composition, which is based on the Amazon shopping services and the payment services of an Italian bank. Finally, Section 8 ends the paper with some concluding remarks. 2 Composing Web Services Service composition [44] is one of the most promising ideas underlying Web services: composite Web services perform new functionalities by interacting with pre-existing services, called component Web services. Service composition has the potential to reduce development time and effort for new applications by re-using published services, thus allowing reusabilty and extensibility. In general, "service composition" can be de

1st International Conference on …, 2003

With the growing number of Web services, importance of composing existing Web Services into more complex services in order to achieve new and more useful solutions is increasing. However, in order to automatically compose new services, existing services need to be encoded in a machine understandable form. The semantics of a service can be described by annotating it with respect to service ontologies. The goals of automatic composition include reducing the complexity of creating composite services as well as choosing an optimal composition among possible options. This paper describes the Interface-Matching Automatic Composition technique that aims for generation of complex Web Services automatically by capturing user's expected outcomes when a set of inputs are provided; the result is a sequence of services whose combined execution achieves the user goals.

2010 Workshops on Database and Expert Systems Applications, 2010

Service Oriented Computing (SOC) is a computing paradigm for the agile development of software based on the orchestration of loosely-coupled services. Services perform functions from the solution of simple atomic requests to execution of complex business processes. Nowadays, new services are created from the manual composition of basic Web Services. It is an arduous and susceptible to errors task. To avoid this problem, it is necessary the existence of discovery and automatic composition mechanisms.This paper presents the specification of a architecture and implementation of a prototype for the automatic composition of Web Services using Artificial Intelligence planning techniques and the WSMO ontological model. Moreover, the paper contains a discussion about design and implementation choices and further improvements.

Proceedings of the eleventh international conference on World Wide Web - WWW '02, 2002

Web services-Web-accessible programs and devices-are a key application area for the Semantic Web. With the proliferation of Web services and the evolution towards the Semantic Web comes the opportunity to automate various Web services tasks. Our objective is to enable markup and automated reasoning technology to describe, simulate, compose, test, and verify compositions of Web services. We take as our starting point the DAML-S DAML+OIL ontology for describing the capabilities of Web services. We define the semantics for a relevant subset of DAML-S in terms of a first-order logical language. With the semantics in hand, we encode our service descriptions in a Petri Net formalism and provide decision procedures for Web service simulation, verification and composition. We also provide an analysis of the complexity of these tasks under different restrictions to the DAML-S composite services we can describe. Finally, we present an implementation of our analysis techniques. This implementation takes as input a DAML-S description of a Web service, automatically generates a Petri Net and performs the desired analysis. Such a tool has broad applicability both as a back end to existing manual Web service composition tools, and as a stand-alone tool for Web service developers.

Web service composition has quickly become an important area of research in the services oriented architecture community. One of the challenges in composition is the existence of heterogeneities between independently created and autonomously managed Web service requesters and Web service providers. Most of the previous work in this area either involve too much human effort or overlook the problem of data heterogeneities, thus cannot automatically generate executable workflow for real-world problems. In this paper ...

Service Oriented Computing and Applications, 2014

With the increasing popularity of Web Services and Service-Oriented Architecture, we need infrastructure to discover and compose Web services. In this paper, we present a generalized semantics-based technique for automatic service composition that combines the rigor of processoriented composition with the descriptiveness of semantics. Our generalized approach presented in this paper introduces the use of a conditional directed acyclic graph where complex interactions, containing control flow, information flow, and pre-/post-conditions are effectively represented. Composition solution obtained is represented semantically as OWLS documents. Web service composition will gain wider acceptance only when users know that the solutions obtained are comprised of trustworthy services. We present a framework that not only uses functional and non-functional attributes provided by the Web service description document but also filters and ranks solutions based on their trust rating that is computed using Centrality Measure of Social Networks. Our contributions are applied for automatic workflow generation in context of the currently important bioinformatics domain. We evaluate our engine for automatic workflow generation of a phylogenetic inference task. We also evaluate our engine