James Scicluna

Combining Scalability and Expressivity in the Automatic Composition of Semantic Web Services

Automatic Web service composition (WSC) is a key component of flexible SOAs. We address WSC at the profile/capability level, where preconditions and effects of services are described in an ontology. In its most expressive formulation, WSC has two sources of complexity: (A) a combinatorial explosion of the services composition space, and (B) worst-case exponential reasoning is needed to determine whether the underlying ontology implies that a particular composition is a solution. Any WSC technology must hence choose a trade-off between scalability and expressivity. We devise new methods for finding better trade-offs. We address (A) by techniques for the automatic generation of heuristic functions. We address (B) by approximate reasoning techniques for the fully expressive case, and by identifying a sub-class where the required reasoning is tractable. We show empirically that our approach scales gracefully to large pools of pre-discovered services, in several test cases.

Semantic annotation and composition of business processes with Maestro

One of the main problems when creating execution-level process models is finding implementations for process activities. Carrying out this activity manually can be time consuming, since it involves searching in large service repositories. We present Maestro for BPMN, a tool that allows to annotate and automatically compose activities within business processes. We explain the main assumptions and algorithms underlying the tool, and we overview what will be demonstrated at ESWC.

A semantically enabled service oriented architecture

The researchers in DERI Innsbruck have been building an execution infrastructure for the Semantic Web Services (SWS) based on the Services Oriented Architecture (SOA) paradigm of loosely coupled components. While SOA is widely acknowledged for its potential to revolutionize the world of computing, that success depends on resolving several fundamental challenges, and especially in the case of open SOA environment the existing specifications do not address several issues. We aim in DERI Innsbruck to define a skeleton of the SWS system and implement the overall infrastructure with the aim of automating service discovery, negotiation, adaptation, composition, invocation, and monitoring as well as service interaction requiring data, protocol, and process mediation. We call this infrastructure a Semantically Enabled Service oriented Architecture (SESA). While there are already several specifications in the space for Web Services there are still elements missing, for example there is no specification describing how the particular components/services of the SWS infrastructure would work together. That work is carried out by DERI researchers in standardization bodies such as OASIS and W3C. In the near future a service-oriented world will consist of an uncountable number of services. Computation will involve services searching for services based on functional and non-functional requirements and an interoperating with those that they select. Services will not be able to interact automatically and SOAs will not scale without signification mechanization of a fixed set of components/services. Hence, machine processable semantics are critical for the next generation of computing, services and SOAs, to reach their full potential. The contribution of DERI Innsbruck is to define and implement the fixed set of services of an infrastructure that must be provided to enable a dynamic discovery, selection, mediation, invocation and inter-operation of the Semantic Web Services to facilitate the SOA revolution towards open environments. We recognize in DERI Innsburck that SOA outside of tightly controlled environment cannot succeed until/unless the semantics issues are addressed. Only with semantics can critical subtasks can be automated leaving humans to focus on higher level problems.

Supporting Execution-Level Business Process Modeling with Semantic Technologies

When creating execution-level process models from conceptual to-be process models, challenges are to find implementations for process activities and to use these implementations correctly. Carrying out these activities manually can be time consuming, since it involves searching in large service repositories and cycles of testing and re-designing. We present Maestro for BPMN , a tool that allows to annotate and automatically compose activities within business processes, and to verify the consistency of an annotated process.

Polynomial-Time Reasoning for Semantic Web Service Composition

Automatic composition of semantic Web services should make use of the ontology in which the services are specified. While the approaches can strongly benefit from doing so, they have to deal with the frame and ramification problems, necessitating worst-case exponential reasoning even to determine the outcome of applying a single Web service. The existing approaches to composition either ignore the background ontology, matching Web services based on concept names and hence removing the need for reasoning; or they employ full-scale reasoning and suffer from the unavoidable performance deficiencies. In our work, we instead look for interesting classes of ontologies where the required reasoning is polynomial. We define a formalism for semantic Web service composition. We present polynomial-time methods for dealing with several of the most commonly used ontology modelling constructs; further extensions are possible. We prove that our methods are correct. We are currently developing an implementation of our techniques.

Service Bundling with seekda! Dynamic Shop

The e-Tourism industry has brought incredible benefits to the consumer. A large — and still growing —umber of holiday and business travels are today booked via the Internet. With the e-Tourism market becoming larger, consumers are looking beyond the usual travel services like hotel room and flight booking. They are increasingly searching for third party services that fit to their journey (e.g. travel insurances, excursions, renting of equipment). This is however not an easy task as the consumers are obliged to surf through many different websites in order to find and book those services. This paper presents a solution to this problem in form of the seekda! dynamic shop. It provides consumers with a single stop-point, e.g., the hotel’s website, where they can semi-automatically aggregate hotelier and third party services for their specific travel. The dynamic shop automatically suggests desired services to the consumers that then only need to choose the ones they prefer.

Modelling e-Tourism Services and Bundles

One of the main challenges in the e-Tourism industry is to present a potential traveller (or travellers) with exciting holiday possibilities during the booking process in order to deliver her/him a memorable experience. Such an experience is not only bound to services offered by a hotel, but also to extra (mostly third-party) services that can be combined together in order to offer a complete and customised holiday package. The diverse nature of such services make it very hard to integrate them together and to achieve this objective. The scope of this paper is to address this problem by defining and describing a set of requirements and data-models that are able to capture different aspects of such services and also a combination thereof.