Tomas Vitvar

A qos-aware selection model for semantic web services

Automating Service Oriented Architectures by augmenting them with semantics will form the basis of the next generation of computing. Selection of service still is an important challenge, especially, when a set of services fulfilling users capabilities requirements have been discovered, among these services which one will be eventually invoked by user is very critical, generally depending on a combined evaluation of qualities of services (Qos). This paper proposes a QoS-based selection of services. Initially we specify a QoS ontology and its vocabulary using the Web Services Modeling Ontology (WSMO) for annotating service descriptions with QoS data. We continue by defining quality attributes and their respective measurements along with a QoS selection model. Finally, we present a fair and dynamic selection mechanism, using an optimum normalization algorithm.

WSMO-PA: Formal Specification of Public Administration Service Model on Semantic Web Service Ontology

In this paper we define a formal model for a public administration service on the basis of the Web service modeling ontology (WSMO). For this purpose we employ the generic public service object model of the governance enterprise architecture (GEA) providing a PA domain specific semantics. We investigate conceptual mappings between PA entities and WSMO elements, and on the real-world use case present the detailed formal PA service model based on the WSMO service model

WSMX: a semantic service oriented middleware for b2b integration

In this paper we present a B2B integration scenario building on the principles of Semantic Web services. For this scenario we show the benefits of semantic descriptions used within the integration process to enable conversation between systems with data and process mediation of services. We illustrate our approach on the WSMX – a middleware platform built specifically to enact semantic service oriented architectures.

Dynamic Service Discovery Through Meta-interactions with Service Providers

Dynamic discovery based on semantic description of services is an essential aspect of the Semantic Web services integration process. Since not all data required for service discovery can always be included in service descriptions, some data needs to be obtained during run-time. In this paper we define a model for service interface allowing required data to be fetched from the service provider during discovery process. We also provide a specification of such interface for WSMO and demonstrate the model on a case scenario from the SWS Challenge implemented using WSMX --- a middleware platform built specifically to enact semantic service oriented architectures.

Semantic SOA to Promote Integration of Heterogeneous B2B Services

Modeling the semantics of business services and their corresponding messages using ontologies enables flexible integration that is more adaptive to business-driven change. In this paper we demonstrate our approach building upon an established semantic Web service framework (WSMX) to facilitate a conversation between heterogeneous services that support both the RosettaNet standard and proprietary information models.

Towards Optimized Data Fetching for Service Discovery

The advent of Service Oriented Architecture makes services the most flexible, platform-independent choice for exposing and integrating business functionality across a network. However, the lack of service discovery mechanisms, that go beyond simple keyword search to enable automated late-binding of service requesters to providers, remains a major problem. Realistic late-binding involves matchmaking of client requests with service descriptions, based on frequently changing fine-grained client requests, and dynamically changing service functionality. The intricacies of service functionality cannot be specified by generic static descriptions since the functionality offered by the service may depend on the client at hand, their specific request and the services current capabilities. In this paper, we propose a semantic framework supporting dynamic data fetching from services during the discovery phase on service instance level entailing a communication overhead which we aim to minimize.

Semantic web services enabled b2b integration

The use of Semantic Web Service (SWS) technologies have been suggested to enable more dynamic B2B integration of heterogeneous systems and partners. We present our approach to accomplish dynamic B2B integrations based on the WSMX SWS environment. We particularly show how WSMX can be made to support the RosettaNet e-business framework and how it can add dynamics to B2B interactions by automating mediation of heterogeneous messages. This is illustrated through a purchasing scenario. The benefits of applying SWS technologies include more flexibility in accepting heterogeneity in B2B integrations and easing back-end integrations. This allows for example to introduce more competition into the purchasing process within e-business frameworks.

Handling heterogeneity in RosettaNet messages

We present a semantic B2B gateway based on the WSMX semantic Service-Oriented Architecture to tackle heterogeneities in RosettaNet messages. We develop a rich RosettaNet ontology and use the axiomatised knowledge and rules to resolve data heterogeneities and to unify unit conversions. We use adaptive executable choreography definitions to easily integrate new sellers into existing RosettaNet collaborations.

Building Application Ontologies from Descriptions of Semantic Web Services

Different ontologies used in semantic web services fields raise numerous interoperation and communication problems with respect to service discovery, composition, and execution. The current approaches for ontology mediation often failed due to their lack of sufficient semantic expressiveness and reasoning capability. In this paper1, we present a novel approach allowing ontologies to provide self-contained semantics for service applications. We show how desired application ontologies can be generated using a new merging algorithm for service ontologies. We also show some experimental results and compare them to the output of the PROMPT ontology merging tool.

Semantic web services selection improved by application ontology with multiple concept relations

Being able to determine and quantify the semantic similarity between ontological concepts is a key requirement for the discovery, selection, and composition of semantic web services. Especially concept similarity is calculated between different service ontologies, it is still a problem. In this paper, we propose an ontology-based approach for semantic service selection which takes into account the heterogeneity of service descriptions. The approach is based on an application ontology (AO), which is merged by different service ontologies and constructed as a semantic net with multiple concept relations. Empirically the proposed method is shown to improve the quality of service selection.