Nikolaos Loutas

Towards a Reference Architecture for Semantically Interoperable Clouds

This paper focuses on the emerging problem of semantic interoperability between heterogeneous cooperating Cloud platforms. We try to pave the way towards a Reference Architecture for Semantically Interoperable Clouds (RASIC). To this end, three fundamental and complementary computing paradigms, namely Cloud computing, Service Oriented Architectures (SOA) and lightweight semantics are used as the main building blocks. The open, generic Reference Architecture for Semantically Interoperable Clouds introduces a scalable, reusable and transferable approach for facilitating the design, deployment and execution of resource intensive SOA services on top of semantically interlinked Clouds. In order to support the development of semantically interoperable Cloud systems based on RASIC, the model of a common Cloud API is also specified.

Cloud Computing Interoperability: The State of Play

Cloud computing is a promising IT paradigm which enables the Internet¢s evolution into a global market of collaborating services. Cloud computing semantic interoperability plays a key role in making this a reality. Towards this direction, a comprehensive and systematic survey of Cloud computing interoperability efforts by standardization groups, industry and research community is carried out. The main objective of this survey is to derive an initial set of semantic interoperability requirements to be supported by existing as well as next generation Cloud systems. Ôhe survey motivates and encourages the Cloud community to adopt a common Cloud computing interoperability framework with core dimensions the creation of a common data model and a standardized Cloud interface (API), which will constitute the base for the development of a semantically interoperable Cloud environment.

A Semantic Interoperability Framework for Cloud Platform as a Service

Given the rapid uptake and the great diversity of PaaS offerings, understanding semantic interoperability at the PaaS level is essential for supporting inter-Cloud cooperation, seamless information exchange and application and data portability. In this vein, this paper introduces a PaaS semantic interoperability framework (PSIF). PSIF studies, models and tries to resolve semantic interoperability conflicts raised during the deployment or the migration of an application by defining the following dimensions: Fundamental PaaS Entities, Types of Semantics, and Levels of Semantic Conflicts. In the context of this paper, the development of common PaaS models and standardized management interfaces are raised as primary requirements in this context. PaaS architectures can then be augmented with a semantic layer that would host the common models and would be the link between heterogeneous PaaS offerings.

Cloud4SOA: A Semantic-Interoperability PaaS Solution for Multi-cloud Platform Management and Portability

Cloud Platform as a Service (PaaS) is a novel, rapidly growing segment in the Cloud computing market. However, the diversity and heterogeneity of today’s existing PaaS offerings raises several interoperability challenges. This introduces adoption barriers due to the lock-in issues that prevent the portability of data and applications from one PaaS to another, “locking” software developers to the first provider they use. This paper introduces the Cloud4SOA solution, a scalable approach to semantically interconnect heterogeneous PaaS offerings across different Cloud providers that share the same technology. The design of the Cloud4SOA solution, extensively presented in this work, comprises of a set of interlinked collaborating software components and models to provide developers and platform providers with a number of core capabilities: matchmaking, management, monitoring and migration of applications. The paper concludes with the presentation of a proof-of-concept implementation of the Cloud4SOA system based on real-life business scenarios.

Public Administration Domain Ontology for a Semantic Web Services EGovernment Framework

In this paper we present a generic public administration (PA) domain ontology. 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 PA domain specific semantics. We describe the ontology using the Web service modeling language (WSML). This domain ontology is implemented in order to be used in semantic Web services architecture for e-government.

Towards a reference service model for the Web of Services

This paper introduces a reference service model (RSM) that closes the gap between two phenomenically contradictory service annotation paradigms: traditional semantic service frameworks and the emerging social annotation of services. RSM aims to (i) facilitate the semantic interlinking between services annotated using different semantic models and (ii) accommodate the bottom-up social annotation of services. RSM was developed following the design science research methodology. To develop RSM, existing semantic service models and SOA service models were reviewed in the light of the six service contracts and examined whether and using which elements each of the models supports in each of the contracts. The identified elements were then fed to a multiphase abstraction exercise. RSM comprises of the following concepts: Service, Service Input, Service Output, Service Context and Service Logic, Service Provider, Service Client and Service Feedback. The paper also maps the concepts of RSM to those of existing semantic service models and positions RSM with respect to related SOA service models. Finally, an implementation of RSM in OWL and two pilot developments that highlight different aspects of RSM are discussed.

Solving Semantic Interoperability Conflicts in Cross-Border E-Government Services

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.

A conceptual analysis of semantic conflicts in pan-European e-government services

This paper presents research in Pan-European Public Services (PEPS) and Pan-European E-Government Services (PEGS). We examine different types of semantic interoperability issues that may arise when actors, information and services from different Member States (MS) need to cooperate and/or interoperate during the public service provision process. The semantic conflict types that arise in these cases are identified and classified according to a typology that is based on the combination of a known classification for semantic conflicts and domain specific concepts from the Governance Enterprise Architecture object model. This conceptual modelling describes and organizes the problem space, documents the requirements and can thus provide the basis for engineering solutions to resolve the identified conflicts.

Inform-consult-empower: a three-tiered approach to eParticipation

While most existing eParticipation projects have embraced the need for citizen engagement to achieve effective democracy, as of yet only limited success has been achieved. This lack of success stems from many challenges and barriers: in some cases, it is a lack of interest in policy issues and low levels of trust in politicians; in others, it is a lack of vision or awareness about the benefits of citizens participation inside the policy-modelling process. This paper describes a three-tiered approach to eParticipation based on a multi-stream policymaking model with three levels of participation: Inform, Consult, Empower. This approach focuses on the level of participation by the user: what are the goals of participation at each of these levels and how do each of these levels of participation relate to current policy-modelling practices. The Puzzled by Policy project will adopt and implement the Inform-Consult-Empower approach, which shows how the social complexity barriers, political culture barriers, technological barriers and organizational structure barriers can be reduced in order to provide effective participation. A use case of how this model will be used to engage Spanish citizens with immigration policy is presented.

Facilitating the Semantic Discovery of eGovernment Services: The SemanticGov Portal

In this paper we propose a way to facilitate the issue of discovering the eGovernment services that address a citizens need. This approach is implemented in an application, which we call a semantic portal. The semantic portal is part of our SemanticGov project architecture. The portals components and its architecture are presented and explained. The portals conceptual modeling is based on the generic public service object model of governance enterprise architecture (GEA) while Web service modeling ontology (WSMO) is used as the semantic Web services framework for application implementation. . We describe the ontologies required using the Web service modeling language (WSML). The reasoning tasks are performed accordingly using a WSML reasoner. Goals are WSMO elements that describe aspects related to user desires. The input to the application consists of information regarding the users profile, i.e. age, marital status etc., while the output is a concrete WSMO Goal that expresses the citizens need. This Goal is forwarded to the discovery engine, which has to discover all the services that address this Goal and return them to the citizen.