Interoperability is one of the most challenging problems in modern cross-organizational information systems, which rely on heterogeneous information and process models. Interoperability becomes very important for e-Government information systems that support cross-organizational communication especially in a cross-border setting. The main goal in this context is to seamlessly provide integrated services to the user (citizen). In this paper we focus on Pan European e-Services and issues related with their integration. Our analysis uses basic concepts of the generic public service model of the Governance Enterprise Architecture (GEA) and of the Web Service Modeling Ontology (WSMO), to express the semantic description of the e-services. Based on the above, we present a mediation infrastructure capable of resolving semantic interoperability conflicts at a pan-European level. We provide several examples to illustrate both the need to solve such semantic conflicts and the actual solutions we propose.
The Web has been continuously growing in the past decade and its growth conveyed to wide use of information systems based on modern Web technologies (e.g. Web services). The distributed nature of the Web challenged the ability of communication amongst independent information systems based on different technologies and heterogeneous data models. To achieve this communication, integration efforts are required, which usually trigger various types of problems. These problems are often referred to as interoperability conflicts and significant effort has been spent on finding the silver bullet to solve them. One of the most promising solutions, that opens new opportunities and at the same time new challenges, is the use of semantic technologies (Fensel, D., Lausen, H., Polleres, A., de Bruijn, J., Stollberg, M., Roman, D., & Domingue, J., 2006; Yanosy, J., 2005).
Nowadays, Public Administrations (PA), especially in the European Union context, have to integrate their technological infrastructure and the underlying data models in order to provide high quality national and cross-border services to the European citizens (Tambouris, E., & Tarabanis, K., 2004; Tambouris, E., Manouselis, N., & Costopoulou, C., 2007). The European Union is currently advancing in this direction by supporting the research on solutions for solving interoperability issues among cross-border e-services, through a number of public financed projects. Such projects (e.g. SemanticGov, SEEMP, eGovBus, R4eGov2) have been targeting the so called, Pan-European eGovernment Services (PEGS).
This article presents a mediation infrastructure developed in the context of the SemanticGov3 project. This infrastructure is able to solve PEGS interoperability conflicts based on the conceptual model of the Web Service Modeling Ontology (WSMO) (Fensel, D., et al., 2006) and semantic technologies. The identification of the interoperability conflicts to be addressed is based on a well-known work by Park and Ram (2004). We adopt their framework and instantiate it in the PA domain by using a generic PA service model as proposed by the Governance Enterprise Architecture (GEA).
In particular, we analyze a comprehensive set of semantic interoperability conflicts and we present here the SemanticGov technical solutions to solve them. The technical solutions are based on alignments between heterogeneous data models and ontologies. Additionally, we give an overview of the infrastructure needed to semi-automatically derive these alignments, such as the human user can interactively create and validate mappings and mapping rules by using a graphical interface. Once such alignments are created, they are ready to be used whenever at run-time heterogeneous data has to be exchanged and mediation is required. The novelty of our work lies on the fact that we propose a comprehensive framework for semantic conflicts analysis and resolution applicable in a Pan-European context, which builds on emerging technologies for semantic-driven data mediation.