No abstract

Abstract. Service orientation is a promising paradigm for offering and consuming functionalities within and across organizations. Ever increasing acceptance of service oriented architectures in combination with the acceptance of the Web as a platform for carrying out electronic business triggers a need for automated methods to find appropriate Web services.Various formalisms for discovery of semantically described services with varying expressivity and complexity have been proposed in the past. However, they are difficult to use since they apply the same formalisms to service descriptions and requests. Furthermore, an intersection-based matchmaking is insufficient to ensure applicability of Web services for a given request. In this paper we show that, although most of prior approaches provide a formal semantics, their pragmatics to describe requests is improper since it differs from the user intention. We introduce distinct formalisms to describe functionalities and service requests. We also provide the formal underpinning and implementation of a matching algorithm.

Service ranking has been long-acknowledged to play a fundamental role in helping users to select the best offerings among services retrieved from a search request. There exist many ranking mechanisms, each one providing ad hoc preference models that offer different levels of expressiveness. Consequently, applying a single mechanism to a particular scenario constrains the user to define preferences based on that mechanism's facilities. Furthermore, a more flexible solution that uses several independent mechanisms will face interoperability issues because of the differences between preference models provided by each ranking mechanism. In order to overcome these issues, we propose a Preferencebased Universal Ranking Integration (PURI) framework that enables the combination of several ranking mechanisms using a common, holistic preference model. Using PURI, different ranking mechanisms are seamlessly and transparently integrated, offering a single façade to define preferences using highly expressive facilities that are not only decoupled from the concrete mechanisms that perform the ranking process, but also allow to exploit synergies from the combination of integrated mechanisms. We also thoroughly present a particular application scenario in the SOA4All EU project and evaluate the benefits and applicability of PURI in further domains.

No abstract

Today's wiki engines are not interoperable. This is an unfortunate consequence of the lack of rigorously specified standards. This technical report presents a complete and validated EBNF-based grammar for Wiki Creole, a community standard for wiki markup. Wiki Creole is also the only standard currently available. Wiki Creole is being specified using prose, leading to inconsistencies and ambiguities. Our grammar uncovered those ambiguities which we fed back into the specification process. The Wiki Creole grammar presented in this report makes the creation of Wiki Creole parsers simple using parser generators, ANTLR in our case. Using a precise specification of wiki markup lets us decouple wiki editors from wiki storage from further wiki processing tools. Based on this decoupling layer we expect innovation on these different parts to proceed independently and at a faster pace than before.